Pressure measurement - Knowledge (XXG)

2982: 45: 3043: 2147:. During the last years this type of gauge became much more user friendly and easier to operate. In the past the instrument was famous for requiring some skill and knowledge to use correctly. For high accuracy measurements various corrections must be applied and the ball must be spun at a pressure well below the intended measurement pressure for five hours before using. It is most useful in calibration and research laboratories where high accuracy is required and qualified technicians are available. Insulation vacuum monitoring of cryogenic liquids is a well suited application for this system too. With the inexpensive and long term stable, weldable sensor, that can be separated from the more costly electronics, it is a perfect fit to all static vacuums. 2205:

induce errors in the results as the movement of the air pressure is trying to force the diaphragm to move in the opposite direction. The errors induced by this are small, but can be significant, and therefore it is always preferable to ensure that the more positive pressure is always applied to the positive (+ve) port and the lower pressure is applied to the negative (-ve) port, for normal 'gauge pressure' application. The same applies to measuring the difference between two vacuums, the larger vacuum should always be applied to the negative (-ve) port. The measurement of pressure via the Wheatstone Bridge looks something like this....

1360:: Force-balanced fused quartz Bourdon tubes use a spiral Bourdon tube to exert force on a pivoting armature containing a mirror, the reflection of a beam of light from the mirror senses the angular displacement and current is applied to electromagnets on the armature to balance the force from the tube and bring the angular displacement to zero, the current that is applied to the coils is used as the measurement. Due to the extremely stable and repeatable mechanical and thermal properties of fused quartz and the force balancing which eliminates most non-linear effects these sensors can be accurate to around 1 1322:: Strain gauge based pressure sensors also use a pressure sensitive element where metal strain gauges are glued on or thin-film gauges are applied on by sputtering. This measuring element can either be a diaphragm or for metal foil gauges measuring bodies in can-type can also be used. The big advantages of this monolithic can-type design are an improved rigidity and the capability to measure highest pressures of up to 15,000 bar. The electrical connection is normally done via a Wheatstone bridge, which allows for a good amplification of the signal and precise and constant measuring results. 1347: 1543: 37: 1816:, a diaphragm, a capsule, or a set of bellows, which will change shape in response to the pressure of the region in question. The deflection of the pressure sensing element may be read by a linkage connected to a needle, or it may be read by a secondary transducer. The most common secondary transducers in modern vacuum gauges measure a change in capacitance due to the mechanical deflection. Gauges that rely on a change in capacitance are often referred to as capacitance manometers. 1857: 1869:. The positioning of the indicator card behind the pointer, the initial pointer shaft position, the linkage length and initial position, all provide means to calibrate the pointer to indicate the desired range of pressure for variations in the behavior of the Bourdon tube itself. Differential pressure can be measured by gauges containing two different Bourdon tubes, with connecting linkages (but is more usually measured via diaphragms or bellows and a balance system). 3303: 4677: 4530: 132: 4576: 4489: 4477: 1134: 4588: 1392:. Generally, this technology is considered to provide very stable readings over time. The squeeze-film pressure sensor is a type of MEMS resonant pressure sensor that operates by a thin membrane that compresses a thin film of gas at high frequency. Since the compressibility and stiffness of the gas film are pressure dependent, the resonance frequency of the squeeze-film pressure sensor is used as a measure of the gas pressure. 1126: 4639: 4564: 4465: 3349:. A Casagrande piezometer will typically have a solid casing down to the depth of interest, and a slotted or screened casing within the zone where water pressure is being measured. The casing is sealed into the drillhole with clay, bentonite or concrete to prevent surface water from contaminating the groundwater supply. In an unconfined aquifer, the water level in the piezometer would not be exactly coincident with the 2217:

resistors. The excitation to the bridge is applied via a constant current. The low-level bridge output is at +O and -O, and the amplified span is set by the gain programming resistor (r). The electrical design is microprocessor controlled, which allows for calibration, the additional functions for the user, such as Scale Selection, Data Hold, Zero and Filter functions, the Record function that stores/displays MAX/MIN.

3295: 1960: 1142: 2473: 4612: 2209: 4665: 4653: 1825: 140: 4689: 4600: 4713: 4629: 4552: 1334:. This technology is employed in challenging applications where the measurement may be highly remote, under high temperature, or may benefit from technologies inherently immune to electromagnetic interference. Another analogous technique utilizes an elastic film constructed in layers that can change reflected wavelengths according to the applied pressure (strain). 4453: 1760: 2990:

Valves. PTC 19.2 provides instructions and guidance for the accurate determination of pressure values in support of the ASME Performance Test Codes. The choice of method, instruments, required calculations, and corrections to be applied depends on the purpose of the measurement, the allowable uncertainty, and the characteristics of the equipment being tested.

200:, fluid levels (by comparing the pressure above and below the liquid) or flow rates (by measuring the change in pressure across a restriction). Technically speaking, most pressure sensors are really differential pressure sensors; for example a gauge pressure sensor is merely a differential pressure sensor in which one side is open to the ambient atmosphere. A 1118: 4701: 4501: 2591: 2036:

atmosphere to measure gauge pressure, open to a second port to measure differential pressure, or can be sealed against a vacuum or other fixed reference pressure to measure absolute pressure. The deformation can be measured using mechanical, optical or capacitive techniques. Ceramic and metallic diaphragms are used. The useful range is above 10

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Additional wires at cathode potential in the line of sight between the ion collector and the grid prevent this effect. In the extraction type the ions are not attracted by a wire, but by an open cone. As the ions cannot decide which part of the cone to hit, they pass through the hole and form an ion beam. This ion beam can be passed on to a:

834: 235:, gauge pressure measurement prevails. Pressure instruments connected to the system will indicate pressures relative to the current atmospheric pressure. The situation changes when extreme vacuum pressures are measured, then absolute pressures are typically used instead and measuring instruments used will be different. 2194: 284:, where atmospheric pressure changes will have a negligible effect on the accuracy of the reading, so venting is not necessary. This also allows some manufacturers to provide secondary pressure containment as an extra precaution for pressure equipment safety if the burst pressure of the primary pressure sensing 2993:

The methods for pressure measurement and the protocols used for data transmission are also provided. Guidance is given for setting up the instrumentation and determining the uncertainty of the measurement. Information regarding the instrument type, design, applicable pressure range, accuracy, output,

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When fluid flows are not in equilibrium, local pressures may be higher or lower than the average pressure in a medium. These disturbances propagate from their source as longitudinal pressure variations along the path of propagation. This is also called sound. Sound pressure is the instantaneous local

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order of metres. In ambient air, suitable ion-pairs are ubiquitously formed by cosmic radiation; in a Penning gauge, design features are used to ease the set-up of a discharge path. For example, the electrode of a Penning gauge is usually finely tapered to facilitate the field emission of electrons.

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version, an electrically heated filament produces an electron beam. The electrons travel through the gauge and ionize gas molecules around them. The resulting ions are collected at a negative electrode. The current depends on the number of ions, which depends on the pressure in the gauge. Hot cathode

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Force-balanced fused quartz Bourdon tube sensors work on the same principle but uses the reflection of a beam of light from a mirror to sense the angular displacement and current is applied to electromagnets to balance the force of the tube and bring the angular displacement back to zero, the current

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In practice, a flattened thin-wall, closed-end tube is connected at the hollow end to a fixed pipe containing the fluid pressure to be measured. As the pressure increases, the closed end moves in an arc, and this motion is converted into the rotation of a (segment of a) gear by a connecting link that

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gauges are based on a metallic pressure-sensing element that flexes elastically under the effect of a pressure difference across the element. "Aneroid" means "without fluid", and the term originally distinguished these gauges from the hydrostatic gauges described above. However, aneroid gauges can be

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is too high. When measuring liquid pressure, a loop filled with gas or a light fluid can isolate the liquids to prevent them from mixing, but this can be unnecessary, for example, when mercury is used as the manometer fluid to measure differential pressure of a fluid such as water. Simple hydrostatic

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of full scale. Due to the extremely fine fused quartz structures which are made by hand and require expert skill to construct these sensors are generally limited to scientific and calibration purposes. Non force-balancing sensors have lower accuracy and reading the angular displacement cannot be done

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conducted experiments with mercury that allowed him to measure the presence of air. He would dip a glass tube, closed at one end, into a bowl of mercury and raise the closed end up out of it, keeping the open end submerged. The weight of the mercury would pull it down, leaving a partial vacuum at the

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is zero-referenced against ambient air pressure, so it is equal to absolute pressure minus atmospheric pressure. A tire pressure gauge is an example of gauge pressure measurement; when it indicates zero, then the pressure it is measuring is the same as the ambient pressure. Most sensors for measuring

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These methods are designed to assist in the evaluation of measurement uncertainty based on current technology and engineering knowledge, taking into account published instrumentation specifications and measurement and application techniques. This Supplement provides guidance in the use of methods to

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These gauges use the attraction of two magnets to translate differential pressure into motion of a dial pointer. As differential pressure increases, a magnet attached to either a piston or rubber diaphragm moves. A rotary magnet that is attached to a pointer then moves in unison. To create different

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Indicator needle axle. This has a spur gear that engages the sector gear (7) and extends through the face to drive the indicator needle. Due to the short distance between the lever arm link boss and the pivot pin and the difference between the effective radius of the sector gear and that of the spur

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in a sensing mechanism to measure stress, or changes in gas density, caused by applied pressure. This technology may be used in conjunction with a force collector, such as those in the category above. Alternatively, resonant technology may be employed by exposing the resonating element itself to the

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Likewise, cold-cathode gauges may be reluctant to start at very low pressures, in that the near-absence of a gas makes it difficult to establish an electrode current - in particular in Penning gauges, which use an axially symmetric magnetic field to create path lengths for electrons that are of the

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is inserted in the vacuum chamber directly, the pins being fed through a ceramic plate in the wall of the chamber. Hot-cathode gauges can be damaged or lose their calibration if they are exposed to atmospheric pressure or even low vacuum while hot. The measurements of a hot-cathode ionization gauge

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readings can be ambiguous without the proper context, as they may represent absolute pressure or gauge pressure without a negative sign. Thus a vacuum of 26 inHg gauge is equivalent to an absolute pressure of 4 inHg, calculated as 30 inHg (typical atmospheric pressure) − 26 inHg

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Piezometers in durable casings can be buried or pushed into the ground to measure the groundwater pressure at the point of installation. The pressure gauges (transducer) can be vibrating-wire, pneumatic, or strain-gauge in operation, converting pressure into an electrical signal. These piezometers

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Maintenance cycles of cold cathode gauges are, in general, measured in years, depending on the gas type and pressure that they are operated in. Using a cold cathode gauge in gases with substantial organic components, such as pump oil fractions, can result in the growth of delicate carbon films and

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The low-pressure sensitivity of hot-cathode gauges is limited by the photoelectric effect. Electrons hitting the grid produce x-rays that produce photoelectric noise in the ion collector. This limits the range of older hot-cathode gauges to 10 Torr and the Bayard–Alpert to about 10 Torr.

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to 10 Torr. Ionization gauge calibration is very sensitive to construction geometry, chemical composition of gases being measured, corrosion and surface deposits. Their calibration can be invalidated by activation at atmospheric pressure or low vacuum. The composition of gases at high vacuums

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The shape of the sensor is important because it is calibrated to work in the direction of air flow as shown by the RED arrows. This is normal operation for the pressure sensor, providing a positive reading on the display of the digital pressure meter. Applying pressure in the reverse direction can

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resistors. An additional laser-trimmed resistor is included to normalize pressure sensitivity variations by programming the gain of an external differential amplifier. This provides good sensitivity and long-term stability. The two ports of the sensor, apply pressure to the same single transducer,

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patented his gauge in France in 1849, and it was widely adopted because of its superior simplicity, linearity, and accuracy; Bourdon is now part of the Baumer group and still manufacture Bourdon tube gauges in France. Edward Ashcroft purchased Bourdon's American patent rights in 1852 and became a

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Liquid-column gauges consist of a column of liquid in a tube whose ends are exposed to different pressures. The column will rise or fall until its weight (a force applied due to gravity) is in equilibrium with the pressure differential between the two ends of the tube (a force applied due to fluid

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claimed that all things are made of air that is simply changed by varying levels of pressure. He could observe water evaporating, changing to a gas, and felt that this applied even to solid matter. More condensed air made colder, heavier objects, and expanded air made lighter, hotter objects. This

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are the most sensitive gauges for very low pressures (also referred to as hard or high vacuum). They sense pressure indirectly by measuring the electrical ions produced when the gas is bombarded with electrons. Fewer ions will be produced by lower density gases. The calibration of an ion gauge is

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that separates regions of different pressure. The amount of deflection is repeatable for known pressures so the pressure can be determined by using calibration. The deformation of a thin diaphragm is dependent on the difference in pressure between its two faces. The reference face can be open to

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If the fluid being measured is significantly dense, hydrostatic corrections may have to be made for the height between the moving surface of the manometer working fluid and the location where the pressure measurement is desired, except when measuring differential pressure of a fluid (for example,

892:(Hg) and water; water is nontoxic and readily available, while mercury's density allows for a shorter column (and so a smaller manometer) to measure a given pressure. The abbreviation "W.C." or the words "water column" are often printed on gauges and measurements that use water for the manometer. 254:

at sea level, but is variable with altitude and weather. If the absolute pressure of a fluid stays constant, the gauge pressure of the same fluid will vary as atmospheric pressure changes. For example, when a car drives up a mountain, the (gauge) tire pressure goes up because atmospheric pressure

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Barometric pressure sensors can have an altitude resolution of less than 1 meter, which is significantly better than GPS systems (about 20 meters altitude resolution). In navigation applications altimeters are used to distinguish between stacked road levels for car navigation and floor

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The American Society of Mechanical Engineers (ASME) has developed two separate and distinct standards on pressure measurement, B40.100 and PTC 19.2. B40.100 provides guidelines on Pressure Indicated Dial Type and Pressure Digital Indicating Gauges, Diaphragm Seals, Snubbers, and Pressure Limiter

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is proportional to the gaseous molecule density multiplied by the electron current emitted from the filament, and these ions pour into the collector to form an ion current. Since the gaseous molecule density is proportional to the pressure, the pressure is estimated by measuring the ion current.

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This is an over-simplified diagram, but you can see the fundamental design of the internal ports in the sensor. The important item here to note is the "diaphragm" as this is the sensor itself. Is it slightly convex in shape (highly exaggerated in the drawing); this is important as it affects the

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Differential pressures are commonly used in industrial process systems. Differential pressure gauges have two inlet ports, each connected to one of the volumes whose pressure is to be monitored. In effect, such a gauge performs the mathematical operation of subtraction through mechanical means,

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equals total vacuum). Most gauges measure pressure relative to atmospheric pressure as the zero point, so this form of reading is simply referred to as "gauge pressure". However, anything greater than total vacuum is technically a form of pressure. For very low pressures, a gauge that uses total

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The spinning-rotor gauge works by measuring how a rotating ball is slowed by the viscosity of the gas being measured. The ball is made of steel and is magnetically levitated inside a steel tube closed at one end and exposed to the gas to be measured at the other. The ball is brought up to speed

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at 59 °F" for measurements taken with mercury or water as the manometric fluid respectively. The word "gauge" or "vacuum" may be added to such a measurement to distinguish between a pressure above or below the atmospheric pressure. Both mm of mercury and inches of water are common pressure

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gauges (such as the mercury column manometer) compare pressure to the hydrostatic force per unit area at the base of a column of fluid. Hydrostatic gauge measurements are independent of the type of gas being measured, and can be designed to have a very linear calibration. They have poor dynamic

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Pressure sensors can vary drastically in technology, design, performance, application suitability and cost. A conservative estimate would be that there may be over 50 technologies and at least 300 companies making pressure sensors worldwide. There is also a category of pressure sensors that are

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is uniform in all directions, so pressure measurements are independent of direction in an immovable (static) fluid. Flow, however, applies additional pressure on surfaces perpendicular to the flow direction, while having little impact on surfaces parallel to the flow direction. This directional

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0.1 mPa is the lowest direct measurement of pressure that is possible with current technology. Other vacuum gauges can measure lower pressures, but only indirectly by measurement of other pressure-dependent properties. These indirect measurements must be calibrated to SI units by a direct

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to measure flow. Differential pressure is measured between two segments of a venturi tube that have a different aperture. The pressure difference between the two segments is directly proportional to the flow rate through the venturi tube. A low pressure sensor is almost always required as the

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Everyday pressure measurements, such as for vehicle tire pressure, are usually made relative to ambient air pressure. In other cases measurements are made relative to a vacuum or to some other specific reference. When distinguishing between these zero references, the following terms are used:

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The effective electrical model of the transducer, together with a basic signal conditioning circuit, is shown in the application schematic. The pressure sensor is a fully active Wheatstone bridge which has been temperature compensated and offset adjusted by means of thick film, laser trimmed

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A pressure sensor may also be used to calculate the level of a fluid. This technique is commonly employed to measure the depth of a submerged body (such as a diver or submarine), or level of contents in a tank (such as in a water tower). For most practical purposes, fluid level is directly

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major manufacturer of gauges. Also in 1849, Bernard Schaeffer in Magdeburg, Germany patented a successful diaphragm (see below) pressure gauge, which, together with the Bourdon gauge, revolutionized pressure measurement in industry. But in 1875 after Bourdon's patents expired, his company

873:(psi) is still in widespread use in the US and Canada, for measuring, for instance, tire pressure. A letter is often appended to the psi unit to indicate the measurement's zero reference; psia for absolute, psig for gauge, psid for differential, although this practice is discouraged by the 1269:: Uses a diaphragm and pressure cavity to create a variable capacitor to detect strain due to applied pressure, capacitance decreasing as pressure deforms the diaphragm. Common technologies use metal, ceramic, and silicon diaphragms. Capacitive pressure sensors are being integrated into 1313:

effect in certain materials such as quartz to measure the strain upon the sensing mechanism due to pressure. This technology is commonly employed for the measurement of highly dynamic pressures. As the basic principle is dynamic, no static pressures can be measured with piezoelectric

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While static gauge pressure is of primary importance to determining net loads on pipe walls, dynamic pressure is used to measure flow rates and airspeed. Dynamic pressure can be measured by taking the differential pressure between instruments parallel and perpendicular to the flow.

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A single-limb liquid-column manometer has a larger reservoir instead of one side of the U-tube and has a scale beside the narrower column. The column may be inclined to further amplify the liquid movement. Based on the use and structure, following types of manometers are used

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designed to measure in a dynamic mode for capturing very high speed changes in pressure. Example applications for this type of sensor would be in the measuring of combustion pressure in an engine cylinder or in a gas turbine. These sensors are commonly manufactured out of

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electrode known as the collector. The current in the collector is proportional to the rate of ionization, which is a function of the pressure in the system. Hence, measuring the collector current gives the gas pressure. There are several sub-types of ionization gauge.

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In the following illustrations of a compound gauge (vacuum and gauge pressure), the case and window has been removed to show only the dial, pointer and process connection. This particular gauge is a combination vacuum and pressure gauge used for automotive diagnosis:

3177:, up to 36,090 feet (11,000 m). Outside that range, an error will be introduced which can be calculated differently for each different pressure sensor. These error calculations will factor in the error introduced by the change in temperature as we go up. 1775:. The technique is very slow and unsuited to continual monitoring, but is capable of good accuracy. Unlike other manometer gauges, the McLeod gauge reading is dependent on the composition of the gas, since the interpretation relies on the sample compressing as an 1897:

that is applied to the coils is used as the measurement. Due to the extremely stable and repeatable mechanical and thermal properties of quartz and the force balancing which eliminates nearly all physical movement these sensors can be accurate to around 1

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This is useful in aircraft, rockets, satellites, weather balloons, and many other applications. All these applications make use of the relationship between changes in pressure relative to the altitude. This relationship is governed by the following equation:

1646:. When expressed as a pressure head, pressure is specified in units of length and the measurement fluid must be specified. When accuracy is critical, the temperature of the measurement fluid must likewise be specified, because liquid density is a function of 1917: 1097:, for example perform this measurement on airplanes to determine airspeed. The presence of the measuring instrument inevitably acts to divert flow and create turbulence, so its shape is critical to accuracy and the calibration curves are often non-linear. 3283:

A pressure sensor may be used to sense the decay of pressure due to a system leak. This is commonly done by either comparison to a known leak using differential pressure, or by means of utilizing the pressure sensor to measure pressure change over time.

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restriction in the connecting pipe is frequently used to avoid unnecessary wear on the gears and provide an average reading; when the whole gauge is subject to mechanical vibration, the case (including the pointer and dial) can be filled with an oil or

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Electrons emitted from the filament move several times in back-and-forth movements around the grid before finally entering the grid. During these movements, some electrons collide with a gaseous molecule to form a pair of an ion and an electron

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gauges in modern language. Aneroid gauges are not dependent on the type of gas being measured, unlike thermal and ionization gauges, and are less likely to contaminate the system than hydrostatic gauges. The pressure sensing element may be a

869:(N·m or kg·m·s). This special name for the unit was added in 1971; before that, pressure in SI was expressed in units such as N·m. When indicated, the zero reference is stated in parentheses following the unit, for example 101 kPa (abs). The 2067: 269:, for example, allows the outside air pressure to be exposed to the negative side of the pressure-sensing diaphragm, through a vented cable or a hole on the side of the device, so that it always measures the pressure referred to ambient 2143:/s), and the deceleration rate is measured after switching off the drive, by electromagnetic transducers. The range of the instrument is 5 to 10 Pa (10 Pa with less accuracy). It is accurate and stable enough to be used as a 1880:; vacuum is sensed as a reverse motion. Some aneroid barometers use Bourdon tubes closed at both ends (but most use diaphragms or capsules, see below). When the measured pressure is rapidly pulsing, such as when the gauge is near a 3705:

Lemme, Max C.; Wagner, Stefan; Lee, Kangho; Fan, Xuge; Verbiest, Gerard J.; Wittmann, Sebastian; Lukas, Sebastian; Dolleman, Robin J.; Niklaus, Frank; van der Zant, Herre S. J.; Duesberg, Georg S.; Steeneken, Peter G. (2020-07-20).

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Pressure range, sensitivity, dynamic response and cost all vary by several orders of magnitude from one instrument design to the next. The oldest type is the liquid column (a vertical tube filled with mercury) manometer invented by

163:, so it is equal to gauge pressure plus atmospheric pressure. Absolute pressure sensors are used in applications where a constant reference is required, like for example, high-performance industrial applications such as monitoring 3357:, the water level in the piezometer indicates the pressure in the aquifer, but not necessarily the water table. Piezometer wells can be much smaller in diameter than production wells, and a 5 cm diameter standpipe is common. 3171: 1145:

Front and back of a silicon pressure sensor chip. Note the etched depression in the front; the sensitive area is extremely thin. The back side shows the circuitry, and rectangular contact pads at top and bottom. Size: 4×4

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to detect strain due to an applied pressure, electrical resistance increasing as pressure deforms the material. Common technology types are silicon (monocrystalline), polysilicon thin film, bonded metal foil, thick film,

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In gauges intended to sense small pressures or pressure differences, or require that an absolute pressure be measured, the gear train and needle may be driven by an enclosed and sealed bellows chamber, called an

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without properly identifying the force units). Using the names kilogram, gram, kilogram-force, or gram-force (or their symbols) as a unit of force is prohibited in SI; the unit of force in SI is the newton (N).

1212:, which turn on or off at a particular pressure. For example, a water pump can be controlled by a pressure switch so that it starts when water is released from the system, reducing the pressure in a reservoir. 4325: 1234:

These types of electronic pressure sensors generally use a force collector (such a diaphragm, piston, Bourdon tube, or bellows) to measure strain (or deflection) due to applied force over an area (pressure).

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and relative cost is provided. Information is also provided on pressure-measuring devices that are used in field environments i.e., piston gauges, manometers, and low-absolute-pressure (vacuum) instruments.

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is similar to a gauge pressure sensor except that it measures pressure relative to some fixed pressure rather than the ambient atmospheric pressure (which varies according to the location and the weather).

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is generally glued (foil strain gauge) or deposited (thin-film strain gauge) onto a membrane. Membrane deflection due to pressure causes a resistance change in the strain gauge which can be electronically

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by a current flowing through it and cooled by the gas surrounding it. If the gas pressure is reduced, the cooling effect will decrease, hence the equilibrium temperature of the wire will increase. The

4352: 1893:. Typical high-quality modern gauges provide an accuracy of ±1% of span (Nominal diameter 100mm, Class 1 EN837-1), and a special high-accuracy gauge can be as accurate as 0.1% of full scale. 368:

went further, having his brother-in-law try the experiment at different altitudes on a mountain, and finding indeed that the farther down in the ocean of atmosphere, the higher the pressure.

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Using atmospheric pressure as reference is usually signified by a "g" for gauge after the pressure unit, e.g. 70 psig, which means that the pressure measured is the total pressure minus

1779:. Due to the compression process, the McLeod gauge completely ignores partial pressures from non-ideal vapors that condense, such as pump oils, mercury, and even water if compressed enough. 1537: 2311:(RTD) can then be used to measure the temperature of the filament. This temperature is dependent on the rate at which the filament loses heat to the surrounding gas, and therefore on the 1844:

of the material of the tube is magnified by forming the tube into a C shape or even a helix, such that the entire tube tends to straighten out or uncoil elastically as it is pressurized.

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Fluid density and local gravity can vary from one reading to another depending on local factors, so the height of a fluid column does not define pressure precisely. So measurements in "

309:, the manufacturer seals a high vacuum behind the sensing diaphragm. If the process-pressure connection of an absolute-pressure transmitter is open to the air, it will read the actual 280:

A sealed gauge reference is very similar, except that atmospheric pressure is sealed on the negative side of the diaphragm. This is usually adopted on high pressure ranges, such as

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circuit to maximize the output of the sensor and to reduce sensitivity to errors. This is the most commonly employed sensing technology for general purpose pressure measurement.

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Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure sensor usually acts as a

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used to measure the pressure of a liquid as well as a gas, and they are not the only type of gauge that can operate without fluid. For this reason, they are often called

1710:). Liquid-column pressure gauges have a highly linear calibration. They have poor dynamic response because the fluid in the column may react slowly to a pressure change. 880:

Because pressure was once commonly measured by its ability to displace a column of liquid in a manometer, pressures are often expressed as a depth of a particular fluid (

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media, whereby the resonant frequency is dependent upon the density of the media. Sensors have been made out of vibrating wire, vibrating cylinders, quartz, and silicon

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Receiver block. This joins the inlet pipe to the fixed end of the Bourdon tube (1) and secures the chassis plate (B). The two holes receive screws that secure the case.

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of full scale. Due to the extremely fine fused quartz structures which must be made by hand these sensors are generally limited to scientific and calibration purposes.

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by not being pointed into the fluid flow. Observation wells give some information on the water level in a formation, but must be read manually. Electrical pressure

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silicon pressure sensor chosen for its excellent performance and long-term stability. Integral temperature compensation is provided over a range of 0–50°C using

1416:: Measures the flow of charged gas particles (ions) which varies due to density changes to measure pressure. Common examples are the Hot and Cold Cathode gauges. 295:

on the reverse side of the sensing diaphragm. Then the output signal is offset, so the pressure sensor reads close to zero when measuring atmospheric pressure.

102:(vacuum & pressure). The widely used Bourdon gauge is a mechanical device, which both measures and indicates and is probably the best known type of gauge. 1439:

waves from the bottom of the open ocean. It has a pressure resolution of approximately 1mm of water when measuring pressure at a depth of several kilometers.

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up to 50 bar are manufactured in this way, since otherwise the atmospheric pressure fluctuation (weather) is reflected as an error in the measurement result.

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or a vacuum) is applied to the other. The difference in liquid levels represents the applied pressure. The pressure exerted by a column of fluid of height

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For much of human history, the pressure of gases like air was ignored, denied, or taken for granted, but as early as the 6th century BC, Greek philosopher

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The Bourdon pressure gauge uses the principle that a flattened tube tends to straighten or regain its circular form in cross-section when pressurized. (A

1698:) even under a strong vacuum. For low pressure differences, light oil or water are commonly used (the latter giving rise to units of measurement such as 1694:

the glass, though under exceptionally clean circumstances, the mercury will stick to glass and the barometer may become stuck (the mercury can sustain a

1330:: Techniques include the use of the physical change of an optical fiber to detect strain due to applied pressure. A common example of this type utilizes 3318:

in a system by measuring the height to which a column of the liquid rises against gravity, or a device which measures the pressure (more precisely, the

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per unit area. This is useful in weather instrumentation, aircraft, automobiles, and any other machinery that has pressure functionality implemented.

2113:. These devices use the sealed chamber as a reference pressure and are driven by the external pressure. Other sensitive aircraft instruments such as 2965:

of the instantaneous sound pressure over a given interval of time. Sound pressures are normally small and are often expressed in units of microbar.

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far end. This validated his belief that air/gas has mass, creating pressure on things around it. Previously, the more popular conclusion, even for

192:

is the difference in pressure between two points. Differential pressure sensors are used to measure many properties, such as pressure drops across

2508:. The filament voltage to ground is usually at a potential of 30 volts, while the grid voltage at 180–210 volts DC, unless there is an optional 4394: 1611:. In other words, the pressure on either end of the liquid (shown in blue in the figure) must be balanced (since the liquid is static), and so 4247: 3791: 3563: 350:, was that air was weightless and it is vacuum that provided force, as in a siphon. The discovery helped bring Torricelli to the conclusion: 1553:

pressure). A very simple version is a U-shaped tube half-full of liquid, one side of which is connected to the region of interest while the

1061: 2519:, with a small ion collector inside the grid. A glass envelope with an opening to the vacuum can surround the electrodes, but usually the 2455:

version is the same, except that electrons are produced in the discharge of a high voltage. Cold cathode gauges are accurate from 10

1106: 2012:

gear, any motion of the Bourdon tube is greatly amplified. A small motion of the tube results in a large motion of the indicator needle.

2650:

shards within the gauge that eventually either short-circuit the electrodes of the gauge or impede the generation of a discharge path.

1365:

with the same precision as a force-balancing measurement, although easier to construct due to the larger size these are no longer used.

1046: 117:

Other methods of pressure measurement involve sensors that can transmit the pressure reading to a remote indicator or control system (

4419: 4387: 4291: 4220: 4085: 3666:

Nagata, Tomio; Terabe, Hiroaki; Kuwahara, Sirou; Sakurai, Shizuki; Tabata, Osamu; Sugiyama, Susumu; Esashi, Masayoshi (1992-08-01).

984:(one atmosphere), which gives one fsw equal to about 0.445 psi. The msw and fsw are the conventional units for measurement of 3872:

Dolleman, Robin J.; Davidovikj, Dejan; Cartamil-Bueno, Santiago J.; van der Zant, Herre S. J.; Steeneken, Peter G. (2016-01-13).

1018:) are most commonly used. Torr and micron usually indicates an absolute pressure, while inHg usually indicates a gauge pressure. 1860:

An original 19th century Eugene Bourdon compound gauge, reading pressure both below and above atmospheric with great sensitivity

2044:). For absolute measurements, welded pressure capsules with diaphragms on either side are often used. Membrane shapes include: 1081:. An instrument facing the flow direction measures the sum of the static and dynamic pressures; this measurement is called the 302:

will never read exactly zero because atmospheric pressure is always changing and the reference in this case is fixed at 1 bar.

4157: 2414:

unstable and dependent on the nature of the gases being measured, which is not always known. They can be calibrated against a

2319:, which uses a single platinum filament as both the heated element and RTD. These gauges are accurate from 10 Torr to 10 4198: 4177: 1389: 1089:. Since dynamic pressure is referenced to static pressure, it is neither gauge nor absolute; it is a differential pressure. 239:

obviating the need for an operator or control system to watch two separate gauges and determine the difference in readings.

5069: 4950: 4492: 4058: 2481: 2447: 2429: 354:

We live submerged at the bottom of an ocean of the element air, which by unquestioned experiments is known to have weight.

3016:

EN 837-3 : Pressure gauges. Diaphragm and capsule pressure gauges. Dimensions, metrology, requirements, and testing.

3588: 3586: 1373:

These types of electronic pressure sensors use other properties (such as density) to infer pressure of a gas, or liquid.

1350:

A force-balanced fused quartz Bourdon tube pressure sensor. The mirror that should be mounted to the armature is absent.

392: 3217:

proportional to pressure. In the case of fresh water where the contents are under atmospheric pressure, 1psi = 27.7 inH

1865:

is usually adjustable. A small-diameter pinion gear is on the pointer shaft, so the motion is magnified further by the

5382: 4009: 3469: 3459: 3365:

or portable readout units, allowing faster or more frequent reading than is possible with open standpipe piezometers.

2550: 1945: 208:

The zero reference in use is usually implied by context, and these words are added only when clarification is needed.

1675:

or venturi), in which case the density ρ should be corrected by subtracting the density of the fluid being measured.

1482: 1021:

Atmospheric pressures are usually stated using hectopascal (hPa), kilopascal (kPa), millibar (mbar) or atmospheres (

4982: 4427: 4023: 3494: 2370:

flowing through it, the resistance (and so the gas pressure) can be determined. This type of gauge was invented by

958:

and a sea-water density of 64 lb/ft. According to the US Navy Diving Manual, one fsw equals 0.30643 msw,

424: 359: 2094:.) This bellows configuration is used in aneroid barometers (barometers with an indicating needle and dial card), 1542: 5285: 4680: 3617:(IMCA D 022 August 2016, Rev. 1 ed.). London, UK: International Marine Contractors' Association. p. 3. 5532: 5361: 5351: 5223: 5213: 5043: 4781: 4579: 4410: 3338: 3228: 3010:

EN 837-1 : Pressure gauges. Bourdon tube pressure gauges. Dimensions, metrology, requirements and testing.

2562: 2556: 2028: 1703: 1346: 306: 4480: 5201: 5176: 5116: 4796: 4737: 4591: 4262: 2953:

pressure deviation from the average pressure caused by a sound wave. Sound pressure can be measured using a

2260:

effect in certain materials such as quartz to measure the strain upon the sensing mechanism due to pressure.

2193: 1850: 1841: 1546: 1082: 929: 385: 4567: 2382:

In two-wire gauges, one wire coil is used as a heater, and the other is used to measure temperature due to

36: 5464: 5275: 5089: 4925: 4900: 4821: 4751: 4730: 4622: 2308: 2121:) have connections both to the internal part of the aneroid chamber and to an external enclosing chamber. 1217: 1194: 976: 902: 896: 870: 842: 434: 342: 4072:

Beckwith, Thomas G.; Marangoni, Roy D. & Lienhard V, John H. (1993). "Measurement of Low Pressures".

1342:: Uses the motion of a wiper along a resistive mechanism to detect the strain caused by applied pressure. 5151: 4960: 4468: 4120: 2359: 2355: 1772: 1479:

The difference in fluid height in a liquid-column manometer is proportional to the pressure difference:

1011: 330: 4374: 2272:

Uses the motion of a wiper along a resistive mechanism to detect the strain caused by applied pressure.

1836:

illustrates this principle.) This change in cross-section may be hardly noticeable, involving moderate

1771:

isolates a sample of gas and compresses it in a modified mercury manometer until the pressure is a few

4615: 2690: 909:" can be converted to SI units as long as attention is paid to the local factors of fluid density and 5504: 5356: 5313: 5206: 5131: 4668: 4514: 4006:

Methods for the Measurement of Fluid Flow in Pipes, Part 1. Orifice Plates, Nozzles and Venturi Tubes

3895: 3719: 3449: 2607: 2509: 2312: 1558: 1401: 989: 419: 266: 259: 217: 106: 3668:"Digital compensated capacitive pressure sensor using CMOS technology for low-pressure measurements" 1856: 5280: 5270: 4811: 4771: 4744: 4519: 4509: 4053: 3504: 3499: 3326:

at a specific point. A piezometer is designed to measure static pressures, and thus differs from a

2580: 2529: 2493: 2421: 2300: 2032: 1785:: from around 10 Torr (roughly 10 Pa) to vacuums as high as 10 Torr (0.1 mPa), 1460: 1331: 1254: 1086: 936:

are still common, as in settings for CPAP machines. Natural gas pipeline pressures are measured in

933: 310: 299: 270: 209: 80: 4555: 114:

vacuum as the zero point reference must be used, giving pressure reading as an absolute pressure.

5231: 4940: 4723: 4642: 3927: 3885: 3430: 3400: 3079: 2279: 2144: 2114: 1990:

Stationary end of Bourdon tube. This communicates with the inlet pipe through the receiver block.

1937: 1881: 1837: 1384: 1221: 997: 913:. Temperature fluctuations change the value of fluid density, while location can affect gravity. 3946: 3013:

EN 837-2 : Pressure gauges. Selection and installation recommendations for pressure gauges.

2985:

Dead-weight tester. This uses known calibrated weights on a piston to generate a known pressure.

2282:

in a sensing mechanism to measure stress, or changes in gas density, caused by applied pressure.

277:

should always read zero pressure when the process pressure connection is held open to the air.

5328: 5074: 4965: 4786: 4287: 4243: 4216: 4194: 4173: 4081: 3919: 3911: 3854: 3787: 3745: 3687: 3559: 3385: 2851: 2461: 2323:, but their calibration is sensitive to the chemical composition of the gases being measured. 2087: 1949: 1898: 1877: 1845: 1798: 1687: 1679: 1464: 1361: 1258: 1022: 985: 943: 889: 17: 3526: 2568: 262:. There are two types of gauge reference pressure: vented gauge (vg) and sealed gauge (sg). 109:, which is set as the zero point, in negative values (for instance, −1 bar or −760 5378: 5265: 5156: 5121: 5096: 4955: 4776: 4100: 3903: 3846: 3815: 3735: 3727: 3679: 3489: 3425: 3390: 3354: 2962: 2367: 2257: 1227:

There are two basic categories of analog pressure sensors: force collector and other types.

1078: 1034: 1026: 993: 955: 910: 213: 131: 5411: 4676: 4529: 3302: 5542: 5494: 5318: 5236: 5171: 5166: 5064: 4930: 4801: 4656: 4575: 4488: 4269: 3405: 2512:

feature, by heating the grid, which may have a high potential of approximately 565 volts.

2497: 2371: 2107: 1713:

When measuring vacuum, the working liquid may evaporate and contaminate the vacuum if its

1664: 1404:

of a gas due to density changes to measure pressure. A common example of this type is the

1209: 1133: 1073: 947: 274: 3976: 3763: 29:

This article is about sensing gas or fluid pressure measurement. Not to be confused with

4476: 3899: 3873: 3723: 1125: 5441: 5333: 5250: 5054: 4816: 4806: 4692: 4587: 4077: 3740: 3707: 3375: 3319: 3192: 2880: 2824: 2627: 2185: 2181: 2171: 1873: 1714: 1683: 1421: 1245: 1110: 1000: 951: 950:(msw) which is defined as equal to one tenth of a bar. The unit used in the US is the 921: 838: 338:

was akin to how gases really do become less dense when warmer, more dense when cooler.

285: 160: 30: 4638: 4563: 4464: 3834: 3667: 3294: 2266:

Uses the physical change of an optical fiber to detect strain due to applied pressure.

291:

There is another way of creating a sealed gauge reference, and this is to seal a high

5526: 5469: 5308: 5186: 5181: 4905: 4826: 4134: 3850: 3819: 3683: 3555: 3334:

of several types can be read automatically, making data acquisition more convenient.

2350: 2041: 1975:

Chassis plate. The dial is attached to this. It contains bearing holes for the axles.

1699: 1672: 1643: 1459:

Piston-type gauges counterbalance the pressure of a fluid with a spring (for example

1310: 1202: 937: 885: 862: 858: 409: 365: 251: 232: 228: 49: 3931: 3578: 3166:{\displaystyle h=(1-(P/P_{\mathrm {ref} })^{0.190284})\times 145366.45\mathrm {ft} } 1959: 1141: 167:, liquid pressure measurement, industrial packaging, industrial process control and 5489: 5484: 5474: 5454: 5141: 5084: 4915: 4632: 3410: 3207: 2599: 2505: 2472: 2452: 2415: 2395: 2346: 2340: 2316: 2304: 2247: 2160: 1941: 1768: 1428: 1424: 1405: 1298: 1274: 1249: 866: 84: 2174:

effect of bonded or formed strain gauges to detect strain due to applied pressure.

1916: 4237: 3907: 3795: 1463:

of comparatively low accuracy) or a solid weight, in which case it is known as a

1060:

Many other hybrid units are used such as mmHg/cm or grams-force/cm (sometimes as

5499: 5196: 5079: 5018: 3464: 3395: 3362: 3350: 3323: 3211: 2545: 2464:

must be used in conjunction with the ionization gauge for accurate measurement.

2243: 2208: 1647: 1634:

In most liquid-column measurements, the result of the measurement is the height

1294: 1117: 1105: 164: 4611: 3353:, especially when the vertical component of flow velocity is significant. In a 1824: 139: 5323: 5303: 5191: 5003: 4998: 4920: 4910: 4791: 4664: 4652: 4536: 4456: 3484: 3474: 3420: 3331: 3327: 2958: 2954: 2572: 2501: 2399: 2383: 2235: 2118: 2110: 2016: 1866: 1833: 1286: 1257:

and sputtered thin film. Generally, the strain gauges are connected to form a

1190: 1094: 1030: 965: 414: 281: 197: 193: 3915: 3858: 3691: 5479: 5459: 5345: 5161: 5146: 4762: 4704: 4688: 4603: 4504: 3731: 3527:"Pressure Sensing 101 – Absolute, Gauge, Differential & Sealed pressure" 3454: 3444: 3380: 3174: 2451:

gauges are accurate from 10 Torr to 10 Torr. The principle behind

2225: 2103: 2099: 2095: 2083: 2071: 1776: 1554: 221: 118: 4599: 4379: 3923: 3749: 2349:

consists of a metal wire open to the pressure being measured. The wire is

1908: 91:. Instruments used to measure and display pressure mechanically are called 4712: 4628: 4551: 3833:

Andrews, M. K.; Turner, G. C.; Harris, P. D.; Harris, I. M. (1993-05-01).

2066: 1885: 1759: 87:. Many techniques have been developed for the measurement of pressure and 5509: 5396: 5126: 5101: 5028: 4945: 4935: 4263:

http://www.wrh.noaa.gov/slc/projects/wxcalc/formulas/pressureAltitude.pdf

3415: 3315: 3061: 2296: 2292: 1890: 1695: 1003:. Both msw and fsw are measured relative to normal atmospheric pressure. 168: 76: 4452: 3033:

PTC 19.2-2010 : The Performance test code for pressure measurement.

2424:

generates electrons, which collide with gas atoms and generate positive

5449: 5421: 5106: 5033: 5023: 5013: 5008: 4716: 3346: 2623: 2590: 2489: 2443: 2299:- its ability to conduct heat increases. In this type of gauge, a wire 1925:

The left side of the face, used for measuring vacuum, is calibrated in

1691: 1690:

is advantageous since this means there will be no pressure errors from

1436: 1159: 347: 334: 255:

goes down. The absolute pressure in the tire is essentially unchanged.

204:

is a device that measures the differential pressure between two inputs.

201: 4700: 4500: 4369: 2331: 5431: 5426: 5416: 5406: 5338: 5136: 5111: 5059: 4869: 4215:(3rd ed.). Van Nostrand Reinhold, New York. pp. 1278–1284. 3479: 2485: 2140: 2091: 2070:

A pile of pressure capsules with corrugated diaphragms in an aneroid

1999:

Link joining pivot pin to lever (5) with pins to allow joint rotation

1054: 292: 88: 68: 4345:

U.S. Navy Diving Manual Revision 7 SS521-AG-PRO-010 0910-LP-115-1921

4135:"Characterization of quartz Bourdon-type high-pressure transducers" 3890: 3808:"Characterization of quartz Bourdon-type high-pressure transducers" 946:

use manometric units: the ambient pressure is measured in units of

833: 105:

A vacuum gauge is used to measure pressures lower than the ambient

4884: 4326:

American Association of State Highway and Transportation Officials

4309:

Soil Mechanics in the design and Construction of the Logan Airport

3977:"Deep-Ocean Bottom Pressure Measurements in the Northeast Pacific" 3293: 3065: 3041: 2980: 2619: 2589: 2492:

is the filament. The three electrodes are a collector or plate, a

2471: 2330: 2207: 2192: 2065: 1958: 1915: 1907: 1855: 1823: 1758: 1577:. Therefore, the pressure difference between the applied pressure 1541: 1474: 1345: 1285:: Measures the displacement of a diaphragm by means of changes in 1140: 1132: 1124: 1116: 1104: 1050: 1042: 888:

calculations. The most common choices for a manometer's fluid are

832: 138: 130: 64: 60: 43: 35: 3612: 2015:

Hair spring to preload the gear train to eliminate gear lash and

1978:

Secondary chassis plate. It supports the outer ends of the axles.

5371: 4879: 4874: 4864: 4859: 4854: 4839: 4541: 3022: 2639: 2631: 2533: 2456: 2363: 2320: 2239: 2234:

Measures the displacement of a diaphragm by means of changes in

2130:

pressure ranges, the spring rate can be increased or decreased.

2037: 1930: 1926: 1719: 1650:. So, for example, pressure head might be written "742.2 mm 1475: 1290: 1270: 1015: 1007: 925: 906: 874: 429: 110: 4383: 3708:"Nanoelectromechanical Sensors Based on Suspended 2D Materials" 2402:, respectively, to measure the temperature of the heated wire. 2618:. The major difference between the two is the position of the 2425: 1663:

heads, which can be converted to S.I. units of pressure using

1155: 1038: 846: 72: 4311:. J. Boston Soc. Civil Eng., Vol 36, No. 2. pp. 192–221. 4284:

Geotechnical Instrumentation for Monitoring Field Performance

1682:

is preferred for its high density (13.534 g/cm) and low

4031:. U.S. Government Printing Office. 1963. pp. A295–A299. 3835:"A resonant pressure sensor based on a squeezed film of gas" 3191:

This is the use of pressure sensors in conjunction with the

2571:

and acceleration voltage and directed at a target to form a

2484:

is composed mainly of three electrodes acting together as a

2418:

which is much more stable and independent of gas chemistry.

1077:

component of pressure in a moving (dynamic) fluid is called

1840:

within the elastic range of easily workable materials. The

884:

inches of water). Manometric measurement is the subject of

854: 125:

Absolute, gauge and differential pressures — zero reference

2224:

Uses a diaphragm and pressure cavity to create a variable

2086:

used a column of liquid such as water or the liquid metal

1876:, relative to ambient atmospheric pressure, as opposed to 3786:

Elastic hologram' pages 113-117, Proc. of the IGC 2010,

2925:

Hot cathode (ionization induced by thermionic emission)

2634:

for operation. Inverted magnetrons can measure down to 1

2295:

increases in density -which may indicate an increase in

1956:

Mechanical details include stationary and moving parts.

1722:(a few 100 Pa) to a few atmospheres (approximately 362:, was essentially the first documented pressure gauge. 159:

is zero-referenced against a perfect vacuum, using an

4211:

Robert M. Besançon, ed. (1990). "Vacuum Techniques".

3636: 3592: 3231: 3091: 2693: 1485: 3361:

are cabled to the surface where they can be read by

3030:

B40.100-2013: Pressure gauges and Gauge attachments.

5440: 5395: 5294: 5258: 5249: 5222: 5042: 4991: 4978: 4893: 4847: 4838: 4761: 4439: 4426: 2575:. In this case a valve lets gas into the grid-cage. 2180:The sensor is generally a temperature compensated, 3249: 3165: 3050:There are many applications for pressure sensors: 2930:Low current measurement; parasitic x-ray emission 2714: 1531: 4351:. Washington, DC.: US Naval Sea Systems Command. 3552:Process control: modeling, design, and simulation 2626:. Neither has a filament, and each may require a 1936:The right portion of the face is used to measure 1467:and may be used for calibration of other gauges. 980:, though elsewhere it states that 33 fsw is 250:Atmospheric pressure is typically about 100 40:Example of the widely used Bourdon pressure gauge 3341:were open wells or standpipes (sometimes called 3225:O. The basic equation for such a measurement is 2998:establish the pressure-measurement uncertainty. 2565:with microchannel plate detector and Faraday cup 1718:gauges can measure pressures ranging from a few 1638:, expressed typically in mm, cm, or inches. The 1162:. Pressure sensors can alternatively be called 1033:. Stress is not a true pressure since it is not 4272:National Oceanic and Atmospheric Administration 3273:= height of fluid column above pressure sensor 3181:levels in buildings for pedestrian navigation. 2654:Comparison of pressure measurement instruments 1993:Moving end of Bourdon tube. This end is sealed. 1981:Posts to join and space the two chassis plates. 1569:is given by the hydrostatic pressure equation, 1532:{\displaystyle h={\frac {P_{a}-P_{o}}{g\rho }}} 1291:linear variable differential transformer (LVDT) 352: 3796:http://www.dspace.cam.ac.uk/handle/1810/225960 2961:in water. The effective sound pressure is the 1591:in a U-tube manometer can be found by solving 1014:(micrometer of mercury), and inch of mercury ( 4395: 3947:"The NOAA DART II Description and Disclosure" 3060:This is where the measurement of interest is 2515:The most common ion gauge is the hot-cathode 393: 8: 1273:technology and it is being explored if thin 1137:Miniature digital barometric pressure sensor 52:with a spring and piston tire-pressure gauge 3606: 3604: 2303:is heated by running current through it. A 1789:measurement, most commonly a McLeod gauge. 1431:force collector, is the critical sensor of 924:is measured in millimetres of mercury (see 5255: 4988: 4844: 4436: 4402: 4388: 4380: 4193:, pp. 92–94, John Wiley & Sons, 2005. 3355:confined aquifer under artesian conditions 3314:is either a device used to measure liquid 3007:EN 472 : Pressure gauge - Vocabulary. 2652: 2476:Bayard–Alpert hot-cathode ionization gauge 2002:Lever, an extension of the sector gear (7) 400: 386: 3889: 3739: 3230: 3196:pressure difference is relatively small. 3155: 3140: 3123: 3122: 3113: 3090: 2813:±10% of reading between 10 and 5⋅10 mbar 2692: 2228:to detect strain due to applied pressure. 1512: 1499: 1492: 1484: 1025:). In American and Canadian engineering, 216:are gauge pressures by convention, while 3874:"Graphene Squeeze-Film Pressure Sensors" 3653:"Understanding Vacuum Measurement Units" 3301: 2938:±20% at 10 and 10 mbar ±100% at 10 mbar 2837:±2.5% of reading between 10 and 10 mbar 2428:. The ions are attracted to a suitably 1154:is a device for pressure measurement of 375: 3517: 2500:. The collector current is measured in 2442:Most ion gauges come in two types: hot 2189:please see pressure flow diagram below. 1853:also manufactured Bourdon tube gauges. 143:silicon piezoresistive pressure sensors 2969:frequency response of pressure sensors 2894:±10% of reading between 10 and 1 mbar 2868:±6% of reading between 10 and 10 mbar 2177:Piezoresistive silicon pressure sensor 1049:system, the unit of pressure was the 920:are still encountered in many fields. 4158:Product brochure from Schoonover, Inc 2862:1000 to 10 mbar (const. temperature) 1912:Indicator front with pointer and dial 1220:in 1643. The U-Tube was invented by 7: 3611:Staff (2016). "2 - Diving physics". 3598:, Table 2‑10. Pressure Equivalents.. 2460:will usually be unpredictable, so a 2027:A second type of aneroid gauge uses 1041:system the unit of pressure was the 916:Although no longer preferred, these 4286:. Wiley-Interscience. p. 117. 4191:A User's Guide to Vacuum Technology 3298:Above-ground casing of a piezometer 3173:This equation is calibrated for an 3046:Industrial wireless pressure sensor 2839:2.5 to 13.5% between 10 and 1 mbar 2439:: 10 - 10 torr (roughly 10 - 10 Pa) 5538:Underwater diving safety equipment 4358:from the original on Dec 28, 2016. 4322:Manual on Suburface Investigations 3159: 3156: 3130: 3127: 3124: 2694: 1763:A McLeod gauge, drained of mercury 1277:can be used as diaphragm material. 25: 4420:Offshore geotechnical engineering 3839:Sensors and Actuators A: Physical 3672:Sensors and Actuators A: Physical 1920:Mechanical side with Bourdon tube 273:. Thus a vented-gauge reference 59:is the measurement of an applied 4711: 4699: 4687: 4675: 4663: 4651: 4637: 4627: 4610: 4598: 4586: 4574: 4562: 4550: 4528: 4499: 4487: 4475: 4463: 4451: 4172:, pp. 100–102, CRC Press, 1998. 2715:{\displaystyle \Delta P=\rho gh} 1678:Although any fluid can be used, 1045:(ba), equal to 1 dyn·cm. In the 992:and the unit of calibration for 4076:(Fifth ed.). Reading, MA: 3614:Guidance for Diving Supervisors 3525:Taskos, Nikolaos (2020-09-16). 2864:10 to 10 mbar (const. voltage) 2594:Penning vacuum gauge (cut-away) 2201:accuracy of the sensor in use. 2151:Electronic pressure instruments 1750:Inverted differential manometer 4117:Instrumentation Reference Book 3146: 3137: 3107: 3098: 2117:and rate of climb indicators ( 1420:A pressure sensor, a resonant 18:Piezoresistive pressure sensor 1: 5070:Mechanically stabilized earth 3975:Eble, M. C.; Gonzalez, F. I. 1557:pressure (which might be the 1193:; it generates a signal as a 1006:In vacuum systems, the units 940:, expressed as "inches W.C." 220:, deep vacuum pressures, and 4822:Hydraulic conductivity tests 4057:. 2006-05-04. Archived from 3908:10.1021/acs.nanolett.5b04251 3851:10.1016/0924-4247(93)80196-N 3764:"What is a Pressure Sensor?" 3684:10.1016/0924-4247(92)80189-A 3208:Level sensor § Pressure 2936:±10% between 10 and 10 mbar 2482:hot-cathode ionization gauge 2394:work in this manner using a 5383:Stress distribution in soil 4342:US Navy (1 December 2016). 4213:The Encyclopedia of Physics 4049:"Techniques of High Vacuum" 4010:British Standards Institute 3550:Bequette, B. Wayne (2003). 3470:List of MOSFET applications 3460:Brake fluid pressure sensor 2794:Slower when filter mounted 2551:Microchannel plate detector 2360:function of its temperature 2167:Piezoresistive strain gauge 1584:and the reference pressure 1248:effect of bonded or formed 1241:Piezoresistive strain gauge 1129:Digital air pressure sensor 1069:Static and dynamic pressure 5559: 4533:Pore pressure measurement 4282:Dunnicliff, John (1993) . 4025:Manual of Barometry (WBAN) 3820:10.1088/0026-1394/42/6/S20 3495:Tensiometer (soil science) 3205: 3077: 2598:There are two subtypes of 2578: 2338: 2335:Pirani vacuum gauge (open) 2315:. A common variant is the 1948:on its outer scale and kg/ 1796: 1696:negative absolute pressure 1208:Some pressure sensors are 1205:materials such as quartz. 1197:of the pressure imposed. 988:pressure exposure used in 894: 231:where a fluid exists in a 135:Natural gas pressure gauge 28: 5286:Preconsolidation pressure 4681:Standard penetration test 4417: 4104:Canadian Museum of Making 3337:The first piezometers in 3250:{\displaystyle P=\rho gh} 2977:Calibration and standards 2785:Temperature fluctuations 2671:Practical pressure range 2446:and cold cathode. In the 2139:(about 2500 or 3800 1471:Liquid column (manometer) 1010:(millimeter of mercury), 857:unit for pressure is the 381: 298:A sealed gauge reference 79:is typically measured in 4782:California bearing ratio 4580:Rotary-pressure sounding 4411:Geotechnical engineering 4236:Nigel S. Harris (1989). 3339:geotechnical engineering 3265:= density of the fluid, 2915:+100 to -50% of reading 2685:Liquid column manometer 2563:Quadrupole mass analyzer 2557:Quadrupole mass analyzer 2524:are always logarithmic. 2366:across the wire and the 1667:and the above formulas. 928:) in most of the world, 307:absolute pressure sensor 5202:Geosynthetic clay liner 5177:Expanded clay aggregate 4797:Proctor compaction test 4738:Crosshole sonic logging 4724:Nuclear densometer test 4481:Geo-electrical sounding 4170:Basic Vacuum Technology 4074:Mechanical Measurements 3986:. NOAA, U.S. Government 3956:. NOAA, U.S. Government 3306:Symbol used in drawings 3289:Groundwater measurement 3002:European (CEN) Standard 2904:Cold cathode (Penning) 2602:ionization gauges: the 2532:). The number of these 1929:on its outer scale and 1872:Bourdon tubes measures 1851:Schaeffer and Budenberg 1828:Membrane-type manometer 930:central venous pressure 360:Torricelli's experiment 5465:Earthquake engineering 5276:Lateral earth pressure 4901:Hydraulic conductivity 4752:Wave equation analysis 4731:Exploration geophysics 4623:Deformation monitoring 4592:Rotary weight sounding 4307:Casagrande, A (1949). 4239:Modern Vacuum Practice 3343:Casagrande piezometers 3307: 3299: 3251: 3167: 3047: 2986: 2780:Capacitance manometer 2716: 2595: 2477: 2336: 2309:resistance thermometer 2213: 2197: 2074: 1964: 1946:pounds per square inch 1931:centimetres of mercury 1921: 1913: 1861: 1829: 1773:millimetres of mercury 1764: 1747:Differential manometer 1549: 1547:Ring balance manometer 1539: 1533: 1400:: Uses the changes in 1383:: Uses the changes in 1351: 1218:Evangelista Torricelli 1147: 1138: 1130: 1122: 1114: 932:and lung pressures in 903:millimetres of mercury 897:Mercury pressure gauge 850: 356: 343:Evangelista Torricelli 318:sealed pressure sensor 144: 136: 53: 41: 4643:Settlement recordings 4568:Rock control drilling 4469:Cone penetration test 4121:Butterworth-Heinemann 3732:10.34133/2020/8748602 3638:US Navy Diving Manual 3594:US Navy Diving Manual 3345:) installed into an 3305: 3297: 3252: 3206:Further information: 3201:Level / depth sensing 3168: 3078:Further information: 3045: 2984: 2888:Thermal conductivity 2859:Thermal conductivity 2717: 2630:potential of about 4 2593: 2475: 2334: 2212:Application schematic 2211: 2196: 2098:, altitude recording 2069: 2023:Diaphragm (membrane) 1962: 1919: 1911: 1859: 1827: 1762: 1642:is also known as the 1545: 1534: 1478: 1349: 1231:Force collector types 1186:, among other names. 1168:pressure transmitters 1144: 1136: 1128: 1120: 1108: 1029:is often measured in 871:pound per square inch 836: 435:Pound per square inch 341:In the 17th century, 218:atmospheric pressures 188:Differential pressure 142: 134: 83:of force per unit of 47: 39: 5505:Agricultural science 5207:Cellular confinement 4115:Boyes, Walt (2008). 4102:The Engine Indicator 4080:. pp. 591–595. 3450:Atmospheric pressure 3269:= standard gravity, 3229: 3089: 2691: 2622:with respect to the 2608:Frans Michel Penning 2510:electron bombardment 2313:thermal conductivity 2287:Thermal conductivity 2278:Uses the changes in 2134:Spinning-rotor gauge 2115:air speed indicators 2106:instruments used in 2005:Sector gear axle pin 1559:atmospheric pressure 1483: 1461:tire-pressure gauges 1402:thermal conductivity 1332:Fiber Bragg Gratings 1164:pressure transducers 1121:Pressure transmitter 990:decompression tables 934:centimeters of water 420:Technical atmosphere 358:This test, known as 267:pressure transmitter 260:atmospheric pressure 107:atmospheric pressure 57:Pressure measurement 5397:Numerical analysis 5281:Overburden pressure 5271:Pore water pressure 5051:Shoring structures 4926:Reynolds' dilatancy 4827:Water content tests 4812:Triaxial shear test 4772:Soil classification 4745:Pile integrity test 4370:Home Made Manometer 4119:(Fourth ed.). 4054:Tel Aviv University 4012:. 1964. p. 36. 3900:2016NanoL..16..568D 3724:2020Resea202048602L 3642:, Section 18‑2.8.3. 3505:Tire-pressure gauge 3500:Time pressure gauge 2738:Capsule dial gauge 2665:Governing equation 2659:Physical phenomena 2655: 2581:Electron ionization 2530:electron ionization 2517:Bayard–Alpert gauge 2422:Thermionic emission 2388:Thermocouple gauges 2362:: by measuring the 2102:, and the altitude 1996:Pivot and pivot pin 1952:on its inner scale. 1255:silicon-on-sapphire 1176:pressure indicators 1087:stagnation pressure 861:(Pa), equal to one 425:Standard atmosphere 378: 311:barometric pressure 300:pressure transducer 271:barometric pressure 222:altimeter pressures 5372:Slab stabilisation 5352:Stability analysis 4268:2017-07-03 at the 4189:John F. O'Hanlon, 3655:. 9 February 2013. 3431:Vacuum engineering 3308: 3300: 3247: 3221:O / 1Pa = 9.81 mmH 3163: 3080:Pressure altimeter 3048: 2987: 2948:Dynamic transients 2749:±5% of full scale 2712: 2653: 2612:inverted magnetron 2596: 2478: 2337: 2280:resonant frequency 2214: 2198: 2156:Metal strain gauge 2145:secondary standard 2075: 1967:Stationary parts: 1965: 1963:Mechanical details 1944:and is scaled in 1933:on its inner scale 1922: 1914: 1882:reciprocating pump 1862: 1830: 1765: 1700:inches water gauge 1550: 1540: 1529: 1385:resonant frequency 1352: 1222:Christiaan Huygens 1148: 1139: 1131: 1123: 1115: 1095:Pitot-static tubes 1057:per square metre. 998:hyperbaric chamber 851: 376: 247:(gauge pressure). 224:must be absolute. 145: 137: 54: 42: 5520: 5519: 5391: 5390: 5367:Sliding criterion 5329:Response spectrum 5245: 5244: 5075:Pressure grouting 4974: 4973: 4834: 4833: 4787:Direct shear test 4493:Permeability test 4249:978-0-07-707099-1 3814:. November 2005. 3792:978-0-9566139-1-2 3565:978-0-13-353640-9 3386:Deadweight tester 3064:, expressed as a 2945: 2944: 2909:Ionization yield 2852:Wheatstone bridge 2668:Limiting factors 2462:mass spectrometer 2411:Ionization gauges 2392:thermistor gauges 2358:of the wire is a 2327:Pirani (one wire) 2125:Magnetic coupling 1927:inches of mercury 1878:absolute pressure 1799:Aneroid altimeter 1654:" or "4.2 in 1527: 1465:deadweight tester 1259:Wheatstone bridge 1210:pressure switches 994:pneumofathometers 944:Underwater divers 907:inches of mercury 831: 830: 155:Absolute pressure 16:(Redirected from 5550: 5379:Bearing capacity 5266:Effective stress 5256: 5157:Land reclamation 5097:Land development 4992:Natural features 4989: 4956:Specific storage 4845: 4777:Atterberg limits 4715: 4703: 4691: 4679: 4667: 4655: 4641: 4631: 4616:Screw plate test 4614: 4602: 4590: 4578: 4566: 4554: 4532: 4503: 4491: 4479: 4467: 4455: 4437: 4404: 4397: 4390: 4381: 4359: 4357: 4350: 4329: 4319: 4313: 4312: 4304: 4298: 4297: 4279: 4273: 4260: 4254: 4253: 4233: 4227: 4226: 4208: 4202: 4187: 4181: 4166: 4160: 4155: 4149: 4148: 4146: 4145: 4131: 4125: 4124: 4112: 4106: 4098: 4092: 4091: 4069: 4063: 4062: 4045: 4039: 4033: 4032: 4030: 4020: 4014: 4013: 4002: 3996: 3995: 3993: 3991: 3981: 3972: 3966: 3965: 3963: 3961: 3951: 3942: 3936: 3935: 3893: 3869: 3863: 3862: 3830: 3824: 3823: 3804: 3798: 3784: 3778: 3777: 3775: 3774: 3760: 3754: 3753: 3743: 3702: 3696: 3695: 3663: 3657: 3656: 3649: 3643: 3634: 3628: 3625: 3619: 3618: 3608: 3599: 3590: 3581: 3576: 3570: 3569: 3547: 3541: 3540: 3538: 3537: 3522: 3490:Sphygmomanometer 3426:Sphygmomanometer 3391:Dynamic pressure 3320:piezometric head 3256: 3254: 3253: 3248: 3172: 3170: 3169: 3164: 3162: 3145: 3144: 3135: 3134: 3133: 3117: 3073:Altitude sensing 3055:Pressure sensing 2963:root mean square 2823:Spinning rotor ( 2721: 2719: 2718: 2713: 2656: 2637: 2614:, also called a 2559:with Faraday cup 2553:with Faraday cup 2406:Ionization gauge 2291:Generally, as a 1741:Simple manometer 1732: 1730: 1727: 1630: 1610: 1538: 1536: 1535: 1530: 1528: 1526: 1518: 1517: 1516: 1504: 1503: 1493: 1172:pressure senders 1079:dynamic pressure 983: 979: 974: 968: 963: 956:standard gravity 954:(fsw), based on 948:metres sea water 918:manometric units 845:(red scale) and 824: 823: 820: 813: 812: 809: 802: 801: 798: 791: 790: 787: 780: 779: 776: 772: 760: 759: 756: 746: 745: 742: 736: 734: 733: 730: 727: 719: 718: 715: 708: 707: 704: 697: 696: 693: 681: 680: 677: 674: 661: 656: 655: 647: 646: 633: 632: 629: 626: 619: 618: 611: 610: 607: 604: 594: 593: 586: 584: 572: 571: 568: 565: 557: 551: 550: 542: 533: 522: 521: 518: 515: 512: 503: 501: 492: 490: 481: 479: 470: 402: 395: 388: 379: 190: 189: 179: 178: 157: 156: 93:pressure gauges, 75:) on a surface. 21: 5558: 5557: 5553: 5552: 5551: 5549: 5548: 5547: 5533:Pressure gauges 5523: 5522: 5521: 5516: 5495:Earth materials 5436: 5398: 5387: 5296: 5290: 5241: 5218: 5172:Earth structure 5167:Erosion control 5065:Ground freezing 5055:Retaining walls 5038: 4980: 4970: 4931:Angle of repose 4889: 4830: 4764: 4757: 4756: 4717:Visible bedrock 4669:Simple sounding 4657:Shear vane test 4433:instrumentation 4432: 4430: 4422: 4413: 4408: 4366: 4355: 4348: 4341: 4338: 4333: 4332: 4320: 4316: 4306: 4305: 4301: 4294: 4281: 4280: 4276: 4270:Wayback Machine 4261: 4257: 4250: 4242:. McGraw-Hill. 4235: 4234: 4230: 4223: 4210: 4209: 4205: 4188: 4184: 4167: 4163: 4156: 4152: 4143: 4141: 4133: 4132: 4128: 4123:. p. 1312. 4114: 4113: 4109: 4099: 4095: 4088: 4071: 4070: 4066: 4047: 4046: 4042: 4036: 4028: 4022: 4021: 4017: 4004: 4003: 3999: 3989: 3987: 3979: 3974: 3973: 3969: 3959: 3957: 3949: 3945:Milburn, Hugh. 3944: 3943: 3939: 3871: 3870: 3866: 3832: 3831: 3827: 3806: 3805: 3801: 3785: 3781: 3772: 3770: 3762: 3761: 3757: 3704: 3703: 3699: 3665: 3664: 3660: 3651: 3650: 3646: 3635: 3631: 3626: 3622: 3610: 3609: 3602: 3591: 3584: 3577: 3573: 3566: 3558:. p. 735. 3549: 3548: 3544: 3535: 3533: 3524: 3523: 3519: 3514: 3509: 3440: 3435: 3406:List of sensors 3371: 3227: 3226: 3224: 3220: 3214: 3136: 3118: 3087: 3086: 3082: 3040: 3027: 3004: 2979: 2950: 2791:±1% of reading 2788:atm to 10 mbar 2767:1000 to 1 mbar 2746:1000 to 1 mbar 2726:atm. to 1 mbar 2689: 2688: 2674:Ideal accuracy 2635: 2588: 2583: 2470: 2440: 2408: 2380: 2372:Marcello Pirani 2343: 2329: 2289: 2153: 2136: 2127: 2108:weather balloon 2090:suspended by a 2064: 2025: 1984: 1822: 1801: 1795: 1786: 1757: 1728: 1725: 1723: 1707: 1684:vapour pressure 1665:unit conversion 1661: 1659: 1653: 1625: 1617: 1612: 1605: 1597: 1592: 1590: 1582: 1519: 1508: 1495: 1494: 1481: 1480: 1473: 1457: 1445: 1435:. DART detects 1357:Force balancing 1282:Electromagnetic 1152:pressure sensor 1103: 1074:Static pressure 1071: 1001:pressure gauges 981: 972: 970: 961: 959: 938:inches of water 899: 821: 818: 816: 810: 807: 805: 799: 796: 794: 788: 785: 783: 777: 774: 770: 768: 757: 754: 752: 743: 740: 738: 731: 728: 725: 724: 722: 716: 713: 711: 705: 702: 700: 694: 691: 689: 678: 675: 672: 670: 659: 653: 651: 644: 642: 630: 627: 624: 622: 616: 614: 608: 605: 602: 600: 591: 589: 582: 580: 569: 566: 563: 561: 555: 548: 546: 540: 531: 519: 516: 513: 510: 508: 499: 497: 488: 486: 477: 475: 468: 406: 377:Pressure units 374: 327: 275:pressure sensor 265:A vented-gauge 244:vacuum pressure 187: 186: 176: 175: 154: 153: 127: 100:compound gauges 34: 23: 22: 15: 12: 11: 5: 5556: 5554: 5546: 5545: 5540: 5535: 5525: 5524: 5518: 5517: 5515: 5514: 5513: 5512: 5502: 5497: 5492: 5487: 5482: 5477: 5472: 5467: 5462: 5457: 5452: 5446: 5444: 5442:Related fields 5438: 5437: 5435: 5434: 5429: 5424: 5419: 5414: 5409: 5403: 5401: 5393: 5392: 5389: 5388: 5386: 5385: 5376: 5375: 5374: 5369: 5364: 5362:Classification 5359: 5354: 5343: 5342: 5341: 5336: 5334:Seismic hazard 5331: 5321: 5316: 5311: 5306: 5300: 5298: 5292: 5291: 5289: 5288: 5283: 5278: 5273: 5268: 5262: 5260: 5253: 5247: 5246: 5243: 5242: 5240: 5239: 5234: 5228: 5226: 5220: 5219: 5217: 5216: 5211: 5210: 5209: 5204: 5199: 5194: 5184: 5179: 5174: 5169: 5164: 5159: 5154: 5149: 5144: 5139: 5134: 5129: 5124: 5119: 5114: 5109: 5104: 5099: 5094: 5093: 5092: 5087: 5082: 5077: 5072: 5067: 5062: 5057: 5048: 5046: 5040: 5039: 5037: 5036: 5031: 5026: 5021: 5016: 5011: 5006: 5001: 4995: 4993: 4986: 4976: 4975: 4972: 4971: 4969: 4968: 4963: 4961:Shear strength 4958: 4953: 4948: 4943: 4938: 4936:Friction angle 4933: 4928: 4923: 4918: 4913: 4908: 4903: 4897: 4895: 4891: 4890: 4888: 4887: 4882: 4877: 4872: 4867: 4862: 4857: 4851: 4849: 4842: 4836: 4835: 4832: 4831: 4829: 4824: 4819: 4817:Oedometer test 4814: 4809: 4807:Sieve analysis 4804: 4799: 4794: 4789: 4784: 4779: 4774: 4769: 4767: 4759: 4758: 4755: 4754: 4748: 4747: 4741: 4740: 4734: 4733: 4727: 4726: 4720: 4719: 4708: 4707: 4696: 4695: 4693:Total sounding 4684: 4683: 4672: 4671: 4660: 4659: 4648: 4647: 4646: 4645: 4635: 4619: 4618: 4607: 4606: 4595: 4594: 4583: 4582: 4571: 4570: 4559: 4558: 4547: 4546: 4545: 4544: 4539: 4525: 4524: 4523: 4522: 4517: 4512: 4496: 4495: 4484: 4483: 4472: 4471: 4460: 4459: 4448: 4447: 4445: 4434: 4424: 4423: 4418: 4415: 4414: 4409: 4407: 4406: 4399: 4392: 4384: 4378: 4377: 4372: 4365: 4364:External links 4362: 4361: 4360: 4337: 4334: 4331: 4330: 4314: 4299: 4292: 4274: 4255: 4248: 4228: 4221: 4203: 4182: 4161: 4150: 4126: 4107: 4093: 4086: 4078:Addison-Wesley 4064: 4061:on 2006-05-04. 4040: 4034: 4015: 3997: 3967: 3937: 3884:(1): 568–571. 3864: 3845:(3): 219–226. 3825: 3799: 3779: 3755: 3697: 3678:(2): 173–177. 3658: 3644: 3629: 3620: 3600: 3582: 3571: 3564: 3542: 3516: 3515: 3513: 3510: 3508: 3507: 3502: 3497: 3492: 3487: 3482: 3477: 3472: 3467: 3462: 3457: 3452: 3447: 3441: 3439: 3436: 3434: 3433: 3428: 3423: 3418: 3413: 3408: 3403: 3398: 3393: 3388: 3383: 3378: 3376:Air core gauge 3372: 3370: 3367: 3292: 3291: 3281: 3280: 3246: 3243: 3240: 3237: 3234: 3222: 3218: 3204: 3203: 3193:venturi effect 3189: 3188: 3161: 3158: 3154: 3151: 3148: 3143: 3139: 3132: 3129: 3126: 3121: 3116: 3112: 3109: 3106: 3103: 3100: 3097: 3094: 3076: 3075: 3058: 3057: 3039: 3036: 3035: 3034: 3031: 3026: 3019: 3018: 3017: 3014: 3011: 3008: 3003: 3000: 2978: 2975: 2974: 2973: 2970: 2949: 2946: 2943: 2942: 2940: 2934: 2933:10 to 10 mbar 2931: 2928: 2926: 2923: 2919: 2918: 2916: 2913: 2912:10 to 10 mbar 2910: 2907: 2905: 2902: 2898: 2897: 2895: 2892: 2889: 2886: 2884: 2881:Seebeck effect 2879:Thermocouple ( 2877: 2873: 2872: 2869: 2866: 2860: 2857: 2855: 2848: 2844: 2843: 2841: 2835: 2834:10 to 10 mbar 2832: 2830: 2828: 2821: 2817: 2816: 2814: 2811: 2810:10 to 10 mbar 2808: 2806: 2803: 2800: 2796: 2795: 2792: 2789: 2786: 2783: 2781: 2778: 2774: 2773: 2770: 2768: 2765: 2763: 2761: 2758: 2754: 2753: 2750: 2747: 2744: 2741: 2739: 2736: 2732: 2731: 2729: 2727: 2724: 2722: 2711: 2708: 2705: 2702: 2699: 2696: 2686: 2683: 2679: 2678: 2677:Response time 2675: 2672: 2669: 2666: 2663: 2660: 2587: 2584: 2577: 2576: 2566: 2560: 2554: 2548: 2488:, wherein the 2469: 2466: 2435: 2407: 2404: 2379: 2376: 2339:Main article: 2328: 2325: 2288: 2285: 2284: 2283: 2276: 2273: 2270: 2269:Potentiometric 2267: 2264: 2261: 2254: 2251: 2238:(reluctance), 2232: 2229: 2222: 2191: 2190: 2182:piezoresistive 2178: 2175: 2172:piezoresistive 2168: 2165: 2157: 2152: 2149: 2135: 2132: 2126: 2123: 2063: 2060: 2059: 2058: 2055: 2054:Flattened tube 2052: 2049: 2031:of a flexible 2024: 2021: 2020: 2019: 2013: 2009: 2006: 2003: 2000: 1997: 1994: 1991: 1986:Moving parts: 1983: 1982: 1979: 1976: 1973: 1969: 1954: 1953: 1934: 1874:gauge pressure 1846:Eugène Bourdon 1821: 1818: 1794: 1791: 1781: 1756: 1753: 1752: 1751: 1748: 1745: 1744:Micromanometer 1742: 1715:vapor pressure 1705: 1657: 1655: 1651: 1623: 1615: 1603: 1595: 1588: 1580: 1525: 1522: 1515: 1511: 1507: 1502: 1498: 1491: 1488: 1472: 1469: 1456: 1453: 1444: 1441: 1422:quartz crystal 1418: 1417: 1409: 1393: 1375: 1374: 1371: 1367: 1366: 1344: 1343: 1339:Potentiometric 1335: 1323: 1315: 1302: 1289:(reluctance), 1278: 1262: 1246:piezoresistive 1236: 1235: 1232: 1111:pressure gauge 1102: 1099: 1083:total pressure 1070: 1067: 952:foot sea water 922:Blood pressure 839:pressure gauge 829: 828: 825: 814: 803: 792: 781: 766: 765:1 lbf/in 762: 761: 750: 747: 720: 709: 698: 687: 683: 682: 668: 665: 662: 657: 648: 639: 635: 634: 620: 612: 598: 595: 587: 578: 574: 573: 558: 552: 543: 537: 534: 529: 525: 524: 505: 494: 483: 472: 465: 462: 458: 457: 454: 451: 448: 445: 442: 438: 437: 432: 427: 422: 417: 412: 407: 405: 404: 397: 390: 382: 373: 370: 326: 323: 305:To produce an 229:working fluids 214:blood pressure 206: 205: 183: 177:Gauge pressure 172: 161:absolute scale 126: 123: 31:Tactile sensor 24: 14: 13: 10: 9: 6: 4: 3: 2: 5555: 5544: 5541: 5539: 5536: 5534: 5531: 5530: 5528: 5511: 5508: 5507: 5506: 5503: 5501: 5498: 5496: 5493: 5491: 5488: 5486: 5483: 5481: 5478: 5476: 5473: 5471: 5470:Geomorphology 5468: 5466: 5463: 5461: 5458: 5456: 5453: 5451: 5448: 5447: 5445: 5443: 5439: 5433: 5430: 5428: 5425: 5423: 5420: 5418: 5415: 5413: 5410: 5408: 5405: 5404: 5402: 5400: 5394: 5384: 5380: 5377: 5373: 5370: 5368: 5365: 5363: 5360: 5358: 5355: 5353: 5350: 5349: 5347: 5344: 5340: 5337: 5335: 5332: 5330: 5327: 5326: 5325: 5322: 5320: 5317: 5315: 5314:Consolidation 5312: 5310: 5309:Frost heaving 5307: 5305: 5302: 5301: 5299: 5293: 5287: 5284: 5282: 5279: 5277: 5274: 5272: 5269: 5267: 5264: 5263: 5261: 5257: 5254: 5252: 5248: 5238: 5235: 5233: 5230: 5229: 5227: 5225: 5221: 5215: 5212: 5208: 5205: 5203: 5200: 5198: 5195: 5193: 5190: 5189: 5188: 5187:Geosynthetics 5185: 5183: 5182:Crushed stone 5180: 5178: 5175: 5173: 5170: 5168: 5165: 5163: 5160: 5158: 5155: 5153: 5150: 5148: 5145: 5143: 5140: 5138: 5137:Cut-and-cover 5135: 5133: 5130: 5128: 5125: 5123: 5120: 5118: 5115: 5113: 5110: 5108: 5105: 5103: 5100: 5098: 5095: 5091: 5088: 5086: 5083: 5081: 5078: 5076: 5073: 5071: 5068: 5066: 5063: 5061: 5058: 5056: 5053: 5052: 5050: 5049: 5047: 5045: 5041: 5035: 5032: 5030: 5027: 5025: 5022: 5020: 5017: 5015: 5012: 5010: 5007: 5005: 5002: 5000: 4997: 4996: 4994: 4990: 4987: 4984: 4977: 4967: 4964: 4962: 4959: 4957: 4954: 4952: 4949: 4947: 4944: 4942: 4939: 4937: 4934: 4932: 4929: 4927: 4924: 4922: 4919: 4917: 4914: 4912: 4909: 4907: 4906:Water content 4904: 4902: 4899: 4898: 4896: 4892: 4886: 4883: 4881: 4878: 4876: 4873: 4871: 4868: 4866: 4863: 4861: 4858: 4856: 4853: 4852: 4850: 4846: 4843: 4841: 4837: 4828: 4825: 4823: 4820: 4818: 4815: 4813: 4810: 4808: 4805: 4803: 4800: 4798: 4795: 4793: 4790: 4788: 4785: 4783: 4780: 4778: 4775: 4773: 4770: 4768: 4766: 4760: 4753: 4750: 4749: 4746: 4743: 4742: 4739: 4736: 4735: 4732: 4729: 4728: 4725: 4722: 4721: 4718: 4714: 4710: 4709: 4706: 4702: 4698: 4697: 4694: 4690: 4686: 4685: 4682: 4678: 4674: 4673: 4670: 4666: 4662: 4661: 4658: 4654: 4650: 4649: 4644: 4640: 4636: 4634: 4630: 4626: 4625: 4624: 4621: 4620: 4617: 4613: 4609: 4608: 4605: 4604:Sample series 4601: 4597: 4596: 4593: 4589: 4585: 4584: 4581: 4577: 4573: 4572: 4569: 4565: 4561: 4560: 4557: 4553: 4549: 4548: 4543: 4540: 4538: 4535: 4534: 4531: 4527: 4526: 4521: 4518: 4516: 4513: 4511: 4508: 4507: 4506: 4502: 4498: 4497: 4494: 4490: 4486: 4485: 4482: 4478: 4474: 4473: 4470: 4466: 4462: 4461: 4458: 4454: 4450: 4449: 4446: 4443: 4438: 4435: 4429: 4428:Investigation 4425: 4421: 4416: 4412: 4405: 4400: 4398: 4393: 4391: 4386: 4385: 4382: 4376: 4373: 4371: 4368: 4367: 4363: 4354: 4347: 4346: 4340: 4339: 4335: 4327: 4323: 4318: 4315: 4310: 4303: 4300: 4295: 4293:0-471-00546-0 4289: 4285: 4278: 4275: 4271: 4267: 4264: 4259: 4256: 4251: 4245: 4241: 4240: 4232: 4229: 4224: 4222:0-442-00522-9 4218: 4214: 4207: 4204: 4200: 4196: 4192: 4186: 4183: 4179: 4175: 4171: 4168:A. Chambers, 4165: 4162: 4159: 4154: 4151: 4140: 4136: 4130: 4127: 4122: 4118: 4111: 4108: 4105: 4103: 4097: 4094: 4089: 4087:0-201-56947-7 4083: 4079: 4075: 4068: 4065: 4060: 4056: 4055: 4050: 4044: 4041: 4038: 4035: 4027: 4026: 4019: 4016: 4011: 4007: 4001: 3998: 3985: 3978: 3971: 3968: 3955: 3948: 3941: 3938: 3933: 3929: 3925: 3921: 3917: 3913: 3909: 3905: 3901: 3897: 3892: 3887: 3883: 3879: 3875: 3868: 3865: 3860: 3856: 3852: 3848: 3844: 3840: 3836: 3829: 3826: 3821: 3817: 3813: 3809: 3803: 3800: 3797: 3793: 3789: 3783: 3780: 3769: 3765: 3759: 3756: 3751: 3747: 3742: 3737: 3733: 3729: 3725: 3721: 3717: 3713: 3709: 3701: 3698: 3693: 3689: 3685: 3681: 3677: 3673: 3669: 3662: 3659: 3654: 3648: 3645: 3641: 3639: 3633: 3630: 3624: 3621: 3616: 3615: 3607: 3605: 3601: 3597: 3595: 3589: 3587: 3583: 3580: 3575: 3572: 3567: 3561: 3557: 3556:Prentice Hall 3553: 3546: 3543: 3532: 3528: 3521: 3518: 3511: 3506: 3503: 3501: 3498: 3496: 3493: 3491: 3488: 3486: 3483: 3481: 3478: 3476: 3473: 3471: 3468: 3466: 3463: 3461: 3458: 3456: 3453: 3451: 3448: 3446: 3443: 3442: 3437: 3432: 3429: 3427: 3424: 3422: 3419: 3417: 3414: 3412: 3409: 3407: 3404: 3402: 3399: 3397: 3394: 3392: 3389: 3387: 3384: 3382: 3379: 3377: 3374: 3373: 3368: 3366: 3364: 3358: 3356: 3352: 3348: 3344: 3340: 3335: 3333: 3329: 3325: 3321: 3317: 3313: 3304: 3296: 3290: 3287: 3286: 3285: 3279: 3276: 3275: 3274: 3272: 3268: 3264: 3260: 3244: 3241: 3238: 3235: 3232: 3213: 3209: 3202: 3199: 3198: 3197: 3194: 3187: 3184: 3183: 3182: 3178: 3176: 3152: 3149: 3141: 3119: 3114: 3110: 3104: 3101: 3095: 3092: 3081: 3074: 3071: 3070: 3069: 3067: 3063: 3056: 3053: 3052: 3051: 3044: 3037: 3032: 3029: 3028: 3024: 3020: 3015: 3012: 3009: 3006: 3005: 3001: 2999: 2995: 2991: 2983: 2976: 2971: 2968: 2967: 2966: 2964: 2960: 2957:in air and a 2956: 2947: 2941: 2939: 2935: 2932: 2929: 2927: 2924: 2921: 2920: 2917: 2914: 2911: 2908: 2906: 2903: 2900: 2899: 2896: 2893: 2891:5 to 10 mbar 2890: 2887: 2885: 2882: 2878: 2875: 2874: 2870: 2867: 2865: 2861: 2858: 2856: 2853: 2849: 2846: 2845: 2842: 2840: 2836: 2833: 2831: 2829: 2826: 2822: 2819: 2818: 2815: 2812: 2809: 2807: 2804: 2801: 2798: 2797: 2793: 2790: 2787: 2784: 2782: 2779: 2776: 2775: 2771: 2769: 2766: 2764: 2762: 2760:Strain gauge 2759: 2756: 2755: 2751: 2748: 2745: 2742: 2740: 2737: 2734: 2733: 2730: 2728: 2725: 2723: 2709: 2706: 2703: 2700: 2697: 2687: 2684: 2681: 2680: 2676: 2673: 2670: 2667: 2664: 2661: 2658: 2657: 2651: 2647: 2643: 2641: 2633: 2629: 2625: 2621: 2617: 2616:Redhead gauge 2613: 2609: 2606:(invented by 2605: 2604:Penning gauge 2601: 2592: 2585: 2582: 2574: 2570: 2567: 2564: 2561: 2558: 2555: 2552: 2549: 2547: 2544: 2543: 2542: 2538: 2535: 2531: 2525: 2522: 2518: 2513: 2511: 2507: 2503: 2499: 2495: 2491: 2487: 2483: 2474: 2467: 2465: 2463: 2458: 2454: 2449: 2445: 2438: 2434: 2431: 2427: 2423: 2419: 2417: 2412: 2405: 2403: 2401: 2397: 2393: 2389: 2385: 2377: 2375: 2373: 2369: 2365: 2361: 2357: 2352: 2348: 2342: 2333: 2326: 2324: 2322: 2318: 2314: 2310: 2306: 2302: 2298: 2294: 2286: 2281: 2277: 2274: 2271: 2268: 2265: 2262: 2259: 2258:piezoelectric 2255: 2253:Piezoelectric 2252: 2249: 2245: 2241: 2237: 2233: 2230: 2227: 2223: 2220: 2219: 2218: 2210: 2206: 2202: 2195: 2187: 2186:laser-trimmed 2183: 2179: 2176: 2173: 2169: 2166: 2162: 2158: 2155: 2154: 2150: 2148: 2146: 2142: 2133: 2131: 2124: 2122: 2120: 2116: 2112: 2109: 2105: 2101: 2097: 2093: 2089: 2085: 2081: 2073: 2068: 2061: 2056: 2053: 2050: 2047: 2046: 2045: 2043: 2039: 2034: 2030: 2022: 2018: 2014: 2010: 2007: 2004: 2001: 1998: 1995: 1992: 1989: 1988: 1987: 1980: 1977: 1974: 1971: 1970: 1968: 1961: 1957: 1951: 1947: 1943: 1939: 1935: 1932: 1928: 1924: 1923: 1918: 1910: 1906: 1902: 1900: 1894: 1892: 1887: 1883: 1879: 1875: 1870: 1868: 1858: 1854: 1852: 1847: 1843: 1839: 1835: 1826: 1819: 1817: 1815: 1810: 1805: 1800: 1792: 1790: 1784: 1780: 1778: 1774: 1770: 1761: 1754: 1749: 1746: 1743: 1740: 1739: 1738: 1734: 1721: 1716: 1711: 1709: 1704:millimetres H 1701: 1697: 1693: 1689: 1686:. Its convex 1685: 1681: 1676: 1674: 1673:orifice plate 1668: 1666: 1649: 1645: 1644:pressure head 1641: 1637: 1632: 1629: 1622: 1618: 1609: 1602: 1598: 1587: 1583: 1576: 1572: 1568: 1564: 1560: 1556: 1548: 1544: 1523: 1520: 1513: 1509: 1505: 1500: 1496: 1489: 1486: 1477: 1470: 1468: 1466: 1462: 1454: 1452: 1449: 1442: 1440: 1438: 1434: 1430: 1426: 1423: 1415: 1414: 1410: 1407: 1403: 1399: 1398: 1394: 1391: 1386: 1382: 1381: 1377: 1376: 1372: 1369: 1368: 1363: 1359: 1358: 1354: 1353: 1348: 1341: 1340: 1336: 1333: 1329: 1328: 1324: 1321: 1320: 1316: 1312: 1311:piezoelectric 1308: 1307: 1306:Piezoelectric 1303: 1300: 1296: 1292: 1288: 1284: 1283: 1279: 1276: 1272: 1268: 1267: 1263: 1260: 1256: 1251: 1250:strain gauges 1247: 1243: 1242: 1238: 1237: 1233: 1230: 1229: 1228: 1225: 1223: 1219: 1213: 1211: 1206: 1204: 1203:piezoelectric 1198: 1196: 1192: 1187: 1185: 1181: 1177: 1173: 1169: 1165: 1161: 1157: 1153: 1143: 1135: 1127: 1119: 1112: 1107: 1100: 1098: 1096: 1090: 1088: 1084: 1080: 1075: 1068: 1066: 1063: 1058: 1056: 1053:, equal to 1 1052: 1048: 1044: 1040: 1036: 1032: 1028: 1024: 1019: 1017: 1013: 1009: 1004: 1002: 999: 995: 991: 987: 982:14.7 psi 978: 967: 957: 953: 949: 945: 941: 939: 935: 931: 927: 923: 919: 914: 912: 908: 904: 898: 893: 891: 887: 886:pressure head 883: 878: 876: 872: 868: 864: 860: 856: 849:(black scale) 848: 844: 840: 835: 826: 815: 804: 793: 782: 767: 764: 763: 751: 748: 721: 710: 699: 688: 685: 684: 669: 666: 663: 658: 649: 640: 637: 636: 621: 613: 599: 596: 588: 579: 576: 575: 559: 553: 544: 538: 535: 530: 527: 526: 506: 495: 484: 473: 466: 463: 460: 459: 455: 452: 449: 446: 443: 440: 439: 436: 433: 431: 428: 426: 423: 421: 418: 416: 413: 411: 408: 403: 398: 396: 391: 389: 384: 383: 380: 371: 369: 367: 366:Blaise Pascal 363: 361: 355: 351: 349: 344: 339: 336: 332: 324: 322: 319: 314: 312: 308: 303: 301: 296: 294: 289: 288:is exceeded. 287: 283: 278: 276: 272: 268: 263: 261: 256: 253: 248: 245: 240: 236: 234: 233:closed system 230: 225: 223: 219: 215: 211: 210:Tire pressure 203: 199: 195: 191: 184: 180: 173: 170: 166: 162: 158: 151: 150: 149: 141: 133: 129: 124: 122: 120: 115: 112: 108: 103: 101: 97: 96:vacuum gauges 94: 90: 86: 82: 78: 74: 70: 66: 62: 58: 51: 50:tire pressure 46: 38: 32: 27: 19: 5490:Biogeography 5485:Hydrogeology 5475:Soil science 5455:Geochemistry 5214:Infiltration 5142:Cut and fill 5085:Soil nailing 4951:Permeability 4916:Bulk density 4633:Inclinometer 4556:Ram sounding 4441: 4344: 4321: 4317: 4308: 4302: 4283: 4277: 4258: 4238: 4231: 4212: 4206: 4190: 4185: 4169: 4164: 4153: 4142:. Retrieved 4139:ResearchGate 4138: 4129: 4116: 4110: 4101: 4096: 4073: 4067: 4059:the original 4052: 4043: 4037: 4024: 4018: 4005: 4000: 3988:. Retrieved 3983: 3970: 3958:. Retrieved 3953: 3940: 3881: 3878:Nano Letters 3877: 3867: 3842: 3838: 3828: 3811: 3802: 3782: 3771:. Retrieved 3767: 3758: 3715: 3711: 3700: 3675: 3671: 3661: 3647: 3637: 3632: 3623: 3613: 3593: 3574: 3551: 3545: 3534:. Retrieved 3530: 3520: 3438:Applications 3411:Isoteniscope 3363:data loggers 3359: 3342: 3336: 3311: 3309: 3288: 3282: 3278:Leak testing 3277: 3270: 3266: 3262: 3261:= pressure, 3258: 3215: 3200: 3190: 3186:Flow sensing 3185: 3179: 3083: 3072: 3059: 3054: 3049: 3038:Applications 2996: 2992: 2988: 2951: 2937: 2863: 2838: 2805:Boyle's law 2648: 2644: 2615: 2611: 2603: 2600:cold-cathode 2597: 2586:Cold cathode 2539: 2526: 2520: 2516: 2514: 2506:electrometer 2479: 2453:cold cathode 2441: 2437:Useful range 2436: 2420: 2416:McLeod gauge 2410: 2409: 2396:thermocouple 2391: 2387: 2381: 2347:Pirani gauge 2344: 2341:Pirani gauge 2317:Pirani gauge 2305:thermocouple 2290: 2248:eddy current 2215: 2203: 2199: 2161:strain gauge 2137: 2128: 2079: 2076: 2026: 1985: 1966: 1955: 1940:pressure or 1903: 1895: 1871: 1863: 1831: 1820:Bourdon tube 1814:Bourdon tube 1813: 1808: 1803: 1802: 1787: 1783:Useful range 1782: 1769:McLeod gauge 1766: 1755:McLeod gauge 1735: 1712: 1677: 1669: 1639: 1635: 1633: 1627: 1620: 1613: 1607: 1600: 1593: 1585: 1578: 1574: 1570: 1566: 1565:and density 1562: 1551: 1458: 1447: 1446: 1429:Bourdon tube 1425:strain gauge 1419: 1412: 1411: 1406:Pirani gauge 1396: 1395: 1379: 1378: 1356: 1355: 1338: 1337: 1326: 1325: 1319:Strain-Gauge 1318: 1317: 1305: 1304: 1299:eddy current 1281: 1280: 1275:2D materials 1265: 1264: 1240: 1239: 1226: 1214: 1207: 1199: 1188: 1183: 1179: 1175: 1171: 1167: 1163: 1151: 1149: 1091: 1072: 1059: 1020: 1005: 942: 917: 915: 900: 881: 879: 867:square metre 852: 686:1 Torr 364: 357: 353: 340: 328: 317: 315: 304: 297: 290: 279: 264: 257: 249: 243: 241: 237: 226: 207: 185: 174: 165:vacuum pumps 152: 146: 128: 116: 104: 99: 95: 92: 85:surface area 56: 55: 26: 5500:Archaeology 5224:Foundations 5197:Geomembrane 5080:Slurry wall 5019:Water table 4983:Interaction 4979:Structures 4966:Sensitivity 4763:Laboratory 3465:Depth gauge 3396:Force gauge 3351:water table 3332:transducers 3324:groundwater 3212:Depth gauge 2922:Ionization 2901:Ionization 2799:Mechanical 2777:Mechanical 2757:Mechanical 2735:Mechanical 2682:Mechanical 2662:Instrument 2610:), and the 2573:sputter gun 2546:Faraday cup 2502:picoamperes 2468:Hot cathode 2448:hot cathode 2244:Hall effect 2119:variometers 2111:radiosondes 2040:(roughly 1 2008:Sector gear 1942:turbo boost 1648:temperature 1448:Hydrostatic 1443:Hydrostatic 1370:Other types 1309:: Uses the 1295:Hall effect 1244:: Uses the 1180:piezometers 1101:Instruments 841:reading in 638:1 atm 528:1 bar 198:air filters 194:oil filters 171:inspection. 5527:Categories 5357:Mitigation 5339:Shear wave 5324:Earthquake 5319:Compaction 5304:Permafrost 5295:Phenomena/ 5192:Geotextile 5117:Embankment 5107:Excavation 5044:Earthworks 5004:Vegetation 4999:Topography 4921:Thixotropy 4911:Void ratio 4894:Properties 4792:Hydrometer 4537:Piezometer 4457:Core drill 4199:0471467154 4178:0585254915 4144:2019-05-05 3891:1510.06919 3812:Metrologia 3773:2018-05-09 3627:Page 2-12. 3536:2020-09-16 3531:ES Systems 3512:References 3485:Pitot tube 3475:MAP sensor 3421:Piezometer 3328:pitot tube 3312:piezometer 2959:hydrophone 2955:microphone 2876:Transport 2847:Transport 2820:Transport 2579:See also: 2521:nude gauge 2400:thermistor 2384:convection 2356:resistance 2250:principle. 2236:inductance 2221:Capacitive 2100:barographs 2096:altimeters 2084:barometers 2051:Corrugated 2029:deflection 2017:hysteresis 1867:gear ratio 1834:party horn 1809:mechanical 1797:See also: 1671:across an 1451:response. 1413:Ionization 1301:principle. 1287:inductance 1266:Capacitive 1191:transducer 1184:manometers 895:See also: 577:1 at 461:1 Pa 331:Anaximenes 282:hydraulics 5480:Hydrology 5460:Petrology 5348:analysis 5346:Landslide 5251:Mechanics 5162:Track bed 5147:Fill dirt 5132:Terracing 4705:Trial pit 4520:Statnamic 4505:Load test 4375:Manometer 3916:1530-6984 3859:0924-4247 3692:0924-4247 3455:Barometer 3445:Altimeter 3381:Barometer 3239:ρ 3175:altimeter 3153:145366.45 3150:× 3105:− 3025:Standards 2972:resonance 2743:Friction 2704:ρ 2695:Δ 2638:10 2256:Uses the 2226:capacitor 2170:Uses the 2164:measured. 2104:telemetry 2082:. (Early 2072:barograph 1938:fuel pump 1777:ideal gas 1555:reference 1524:ρ 1506:− 1224:in 1661. 1113:in action 1037:. In the 456:(lbf/in) 286:diaphragm 242:Moderate 227:For most 119:telemetry 48:Checking 5510:Agrology 5399:software 5297:problems 5127:Causeway 5102:Landfill 5029:Subgrade 4946:Porosity 4941:Cohesion 4353:Archived 4328:page 182 4324:, 1988, 4266:Archived 3984:noaa.gov 3954:noaa.gov 3932:23331693 3924:26695136 3750:32766550 3718:: 1–25. 3712:Research 3416:Pressure 3369:See also 3316:pressure 3142:0.190284 3062:pressure 2850:Pirani ( 2569:Ion lens 2496:, and a 2494:filament 2378:Two-wire 2301:filament 2297:pressure 2293:real gas 2275:Resonant 2246:, or by 2231:Magnetic 2033:membrane 1891:glycerin 1838:stresses 1731: Pa 1688:meniscus 1380:Resonant 1314:sensors. 1297:, or by 1195:function 169:aviation 77:Pressure 5450:Geology 5422:SVSlope 5232:Shallow 5152:Grading 5090:Tieback 5034:Subsoil 5024:Bedrock 5014:Topsoil 5009:Terrain 4802:R-value 4765:testing 4515:Dynamic 4442:in situ 4440:Field ( 4336:Sources 3990:4 April 3960:4 April 3896:Bibcode 3741:7388062 3720:Bibcode 3347:aquifer 2802:McLeod 2624:cathode 2490:cathode 2444:cathode 2368:current 2364:voltage 2263:Optical 2088:mercury 2080:aneroid 2062:Bellows 2057:Capsule 1886:orifice 1804:Aneroid 1793:Aneroid 1692:wetting 1680:mercury 1437:tsunami 1427:with a 1397:Thermal 1327:Optical 1160:liquids 911:gravity 890:mercury 735:⁠ 723:⁠ 690:133.322 615:735.559 523:lbf/in 507:1 Pa = 496:1 Pa = 485:1 Pa = 474:1 Pa = 467:1 Pa = 453:(Torr) 348:Galileo 335:Miletus 325:History 202:DP cell 5543:Vacuum 5432:Plaxis 5427:UTEXAS 5417:SVFlux 5407:SEEP2D 5259:Forces 5112:Trench 5060:Gabion 4870:Gravel 4510:Static 4290: 4246: 4219: 4197: 4176: 4084: 3930: 3922: 3914: 3857: 3794:here: 3790: 3748: 3738: 3690: 3562: 3480:MOSFET 3257:where 3210:, and 2504:by an 2486:triode 2430:biased 2351:heated 2092:vacuum 1842:strain 1455:Piston 1055:sthene 1035:scalar 1027:stress 1012:micron 975: 964: 905:" or " 863:newton 859:pascal 817:51.714 671:14.695 660:1.0332 623:14.223 562:14.503 556:750.06 541:1.0197 498:7.5006 487:9.8692 476:1.0197 450:(atm) 444:(bar) 410:Pascal 293:vacuum 89:vacuum 69:liquid 5412:STABL 4885:Loess 4848:Types 4356:(PDF) 4349:(PDF) 4029:(PDF) 3980:(PDF) 3950:(PDF) 3928:S2CID 3886:arXiv 3401:Gauge 3322:) of 3066:force 2871:Fast 2772:Fast 2752:Slow 2620:anode 1884:, an 1720:torrs 1156:gases 1062:kg/cm 1051:pieze 1043:barye 986:diver 971:0.444 969:, or 960:0.030 882:e.g., 806:0.068 795:0.070 784:0.068 753:0.019 739:0.001 712:0.001 701:0.001 652:1.013 601:0.967 590:0.980 547:0.986 509:0.000 504:Torr 447:(at) 441:(Pa) 372:Units 81:units 65:fluid 63:by a 61:force 5237:Deep 4880:Loam 4875:Peat 4865:Sand 4860:Silt 4855:Clay 4840:Soil 4542:Well 4288:ISBN 4244:ISBN 4217:ISBN 4195:ISBN 4174:ISBN 4082:ISBN 3992:2020 3962:2020 3920:PMID 3912:ISSN 3855:ISSN 3788:ISBN 3746:PMID 3716:2020 3688:ISSN 3640:2016 3596:2016 3579:NIST 3560:ISBN 3023:ASME 2825:drag 2640:Torr 2534:ions 2498:grid 2457:Torr 2426:ions 2390:and 2321:Torr 2240:LVDT 2159:The 2048:Flat 2038:Torr 1702:and 1433:DART 1390:MEMS 1271:CMOS 1182:and 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