122:
25:
197:
The simplest dewars allow the gas to escape either through an open top or past a loose-fitting stopper. More sophisticated dewars trap the gas above the liquid, and hold it at high pressure. This increases the boiling point of the liquid, allowing it to be stored for extended periods. Excessive
201:
The method of decanting liquid from a dewar depends upon its design. Simple dewars may be tilted, to pour liquid from the neck. Self-pressurising designs use the pressure of the gas in the top of the dewar to force the liquid upward through a pipe leading to the neck.
319:
Secondly, if a dewar is left open to the air for extended periods, atmospheric chemicals can condense or freeze on contact with the cryogenic material. This can introduce contaminants. If these materials freeze, for example, water vapor becoming
198:
vapour pressure is released automatically through safety valves. Dewars are also designed to be resistant to any sort of puncture to preserve the contents, as cryogens are costly to produce, and some (like helium) are in limited global supply.
188:
between the interior and exterior of the dewar, which reduces the rate at which the contents boil away. Precautions are taken in the design of dewars to safely manage the gas which is released as the liquid slowly boils.
308:. In dewars with an open top, the gas simply escapes into the surrounding area. However, very high pressures can build up inside sealed dewars, and precautions are taken to minimise the risk of explosion. One or more
304:
Firstly, no dewar can provide perfect thermal insulation and the cryogenic liquid slowly boils away, which yields an enormous quantity of gas. This is known as the liquid nitrogen
461:
382:
1690:
1669:
316:, the pressure-relief devices of a tank of liquid nitrogen were sealed with brass plugs. As a result, the tank failed catastrophically and exploded.
1779:
42:
1305:
305:
180:, flasks with loose-fitting stoppers, and self-pressurising tanks. All dewars have walls constructed from two or more layers, with a high
454:
360:
89:
1366:
108:
61:
1343:
68:
46:
1813:
1634:
1523:
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75:
1338:
390:
57:
1414:
1383:
1295:
35:
1808:
1538:
869:
940:
339:
hazard. Users are trained to store dewars only in a well-ventilated area, and before transporting dewars in an
543:
1373:
1290:
313:
170:
1798:
976:
724:
693:
312:
allow gas to vent away from the dewar whenever the pressure becomes excessive. In an incident in 2006 at
966:
844:
556:
309:
176:
Cryogenic storage dewars can range widely in size and may take several different forms, including open
1262:
922:
764:
343:, the excess gas pressure is vented away and the dewars are sent unaccompanied to their destination.
82:
1803:
950:
759:
674:
611:
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989:
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1353:
1135:
1109:
884:
779:
404:
263:
230:
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150:
126:
324:, they can block the openings, leading to pressure buildup and the risk of an explosion.
1755:
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1063:
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714:
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701:
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533:
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142:
405:"State Fire Marshal's Alert: University Campus Liquid Nitrogen Cylinder Explosion"
1654:
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1234:
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1145:
1020:
984:
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24:
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819:
774:
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719:
616:
518:
470:
1750:
1548:
1198:
811:
626:
586:
528:
301:, and their storage vessels are designed to reduce the associated risk.
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1574:
1564:
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1193:
874:
824:
340:
1715:
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1508:
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1130:
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879:
839:
439:
146:
1068:
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181:
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327:
Thirdly, the gas escaping from a dewar can gradually displace the
120:
1239:
538:
1621:
1440:
1260:
920:
481:
443:
169:, who developed it for his own work. They are commonly used in
332:
321:
18:
184:
maintained between the layers. This provides very good
125:
A self-pressurising dewar (silver) being filled with
1728:
1678:
1632:
1588:
1557:
1501:
1453:
1392:
1352:
1329:
1273:
1217:
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998:
975:
959:
933:
799:
733:
645:
570:
492:
49:. Unsourced material may be challenged and removed.
426:"Fermilab Environment, Safety, and Health Manual"
455:
8:
1415:Nuclear magnetic resonance (NMR) instrument
335:in the surrounding area, which presents an
1642:
1629:
1618:
1450:
1437:
1270:
1257:
930:
917:
489:
478:
462:
448:
440:
109:Learn how and when to remove this message
1780:Instruments used in medical laboratories
209:
1296:Inductively coupled plasma (ICP) device
352:
1344:Transmission electron microscope (TEM)
383:"Cryogenic liquids — characteristics"
7:
47:adding citations to reliable sources
412:Texas Department of Insurance (TDI)
367:. September 5, 2006. Archived from
1339:Scanning electron microscope (SEM)
129:from a larger storage tank (white)
14:
1384:Thermogravimetric analyzer (TGA)
1194:Nuclear magnetic resonance (NMR)
23:
34:needs additional citations for
1:
165:. It is named after inventor
365:OSU Department of Chemistry
141:) is a specialised type of
1830:
211:Selected expansion ratios
16:Vacuum insulated container
1777:
1645:
1628:
1617:
1539:Time-domain reflectometer
1449:
1436:
1306:Liquid chromatograph (LC)
1269:
1256:
929:
916:
488:
477:
297:Cryogens present several
58:"Cryogenic storage dewar"
314:Texas A&M University
1374:Melting-point apparatus
755:Cryogenic storage dewar
171:low-temperature physics
135:cryogenic storage dewar
1311:Mass spectrometer (MS)
1301:Gas chromatograph (GC)
310:pressure-relief valves
130:
1686:Acid-resistant gloves
1367:differential scanning
393:on February 18, 2012.
371:on September 5, 2006.
124:
1814:Laboratory equipment
1263:Analytical chemistry
765:Laminar flow cabinet
471:Laboratory equipment
414:. February 22, 2006.
161:are much lower than
43:improve this article
1635:Personal protective
544:Meker–Fisher burner
212:
1478:Function generator
1461:Bench power supply
1400:Analytical balance
1161:Ostwald viscometer
1156:Graduated cylinder
895:Inoculation needle
361:"Cryogenic Safety"
210:
186:thermal insulation
131:
1786:
1785:
1773:
1772:
1769:
1768:
1746:Fire extinguisher
1736:Biosafety cabinet
1724:
1723:
1613:
1612:
1609:
1608:
1544:Transistor tester
1534:Spectrum analyzer
1432:
1431:
1428:
1427:
1252:
1251:
1248:
1247:
1124:Measuring devices
946:Soxhlet extractor
912:
911:
908:
907:
860:Spectrophotometer
855:Pipeclay triangle
607:Mortar and pestle
295:
294:
145:used for storing
119:
118:
111:
93:
1821:
1809:Industrial gases
1643:
1630:
1619:
1524:Network analyzer
1451:
1438:
1271:
1258:
931:
918:
900:Inoculation loop
770:Microtiter plate
710:Test tube holder
602:Magnetic stirrer
490:
479:
464:
457:
450:
441:
434:
433:
422:
416:
415:
409:
401:
395:
394:
389:. Archived from
379:
373:
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306:evaporation rate
213:
173:and chemistry.
163:room temperature
114:
107:
103:
100:
94:
92:
51:
27:
19:
1829:
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1824:
1823:
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1819:
1818:
1789:
1788:
1787:
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1765:
1761:Solvent cabinet
1720:
1691:Eyewash station
1674:
1639:
1637:equipment (PPE)
1636:
1624:
1605:
1584:
1553:
1497:
1488:Pulse generator
1454:Control devices
1445:
1424:
1388:
1354:Thermochemistry
1348:
1325:
1265:
1244:
1213:
1170:
1136:Conical measure
1119:
1088:
1025:
994:
971:
955:
925:
904:
885:Test tube brush
795:
780:Picotiter plate
743:
729:
725:Lab drying rack
684:Extension clamp
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151:liquid nitrogen
127:liquid nitrogen
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1758:
1756:Safety cabinet
1753:
1748:
1743:
1738:
1732:
1730:
1726:
1725:
1722:
1721:
1719:
1718:
1716:Safety goggles
1713:
1711:Safety glasses
1708:
1706:Nitrile gloves
1703:
1701:Medical gloves
1698:
1693:
1688:
1682:
1680:
1676:
1675:
1673:
1672:
1667:
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1598:
1596:Alligator clip
1592:
1590:
1586:
1585:
1583:
1582:
1577:
1572:
1570:Soldering iron
1567:
1561:
1559:
1555:
1554:
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1536:
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1516:
1514:Logic analyzer
1511:
1505:
1503:
1499:
1498:
1496:
1495:
1490:
1485:
1480:
1475:
1474:
1473:
1471:Voltage source
1468:
1466:Current source
1457:
1455:
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1446:
1441:
1434:
1433:
1430:
1429:
1426:
1425:
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1407:
1405:Colony counter
1402:
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1089:
1087:
1086:
1081:
1076:
1071:
1066:
1061:
1056:
1051:
1046:
1044:Vacuum (Dewar)
1041:
1035:
1033:
1027:
1026:
1024:
1023:
1018:
1013:
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717:
715:Test tube rack
712:
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699:
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691:
690:Funnel support
688:
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667:
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646:
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629:
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619:
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609:
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599:
597:Liquid whistle
594:
589:
583:
581:
579:
578:
575:
571:
568:
567:
565:
564:
562:Vacuum dry box
559:
554:
549:
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541:
536:
531:
526:
524:Heating mantle
521:
516:
511:
509:Alcohol burner
505:
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469:
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299:safety hazards
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159:boiling points
117:
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15:
13:
10:
9:
6:
4:
3:
2:
1826:
1815:
1812:
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1799:Vacuum flasks
1797:
1796:
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1699:
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1677:
1671:
1670:Safety shower
1668:
1666:
1663:
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1648:
1647:
1644:
1641:
1638:
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1627:
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1602:
1599:
1597:
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1591:
1587:
1581:
1580:Wire stripper
1578:
1576:
1573:
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1560:
1556:
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1456:
1452:
1448:
1444:
1439:
1435:
1421:
1418:
1416:
1413:
1411:
1410:Spiral plater
1408:
1406:
1403:
1401:
1398:
1397:
1395:
1391:
1385:
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1380:
1377:
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1299:
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1289:
1287:
1284:
1282:
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1274:Compositional
1272:
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828:
826:
823:
821:
818:
816:Balance brush
815:
813:
810:
808:
805:
804:
802:
798:
792:Weighing dish
791:
789:Weighing boat
788:
786:
783:
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766:
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681:
680:Burette clamp
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514:Bunsen burner
512:
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199:
192:
190:
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183:
179:
174:
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160:
156:
155:liquid helium
152:
148:
144:
140:
136:
128:
123:
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110:
102:
91:
88:
84:
81:
77:
74:
70:
67:
63:
60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
1741:Fire blanket
1679:Eye and hand
1665:Rubber apron
1529:Oscilloscope
1493:Potentiostat
1420:Plate reader
1316:pH indicator
1286:CHN analyzer
1281:AutoAnalyzer
1074:Round-bottom
967:Boston round
830:Filter paper
785:Refrigerator
754:
702:Retort stand
670:Clamp holder
666:Beaker clamp
632:Vortex mixer
627:Stirring rod
622:Static mixer
552:Teclu burner
429:
420:
411:
399:
391:the original
387:Linde Canada
386:
377:
369:the original
364:
355:
337:asphyxiation
326:
318:
303:
296:
200:
196:
175:
143:vacuum flask
138:
134:
132:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
1729:Other items
1655:Face shield
1502:Measurement
1483:Galvanostat
1443:Electronics
1393:Other items
1379:Thermometer
1362:Calorimeter
1291:Colorimeter
1235:Gas syringe
1218:Other items
1146:Eye dropper
1021:Watch glass
1006:Evaporating
985:Cold finger
800:Other items
706:Screw clamp
698:Pinch clamp
687:Flask clamp
637:Wash bottle
592:Homogenizer
167:James Dewar
137:(or simply
1804:Cryogenics
1793:Categories
1660:Respirator
1601:Test probe
1519:Multimeter
1331:Microscopy
1151:Eudiometer
1115:Separatory
1084:Volumetric
1049:Erlenmeyer
977:Condensers
941:Dean–Stark
890:Wire brush
850:Microscope
845:Centrifuge
820:Cork borer
775:Petri dish
750:Agar plate
737:Containers
720:Wire gauze
557:Water bath
519:Desiccator
347:References
99:March 2012
69:newspapers
1751:Fume hood
1696:Glove box
1549:Voltmeter
934:Apparatus
923:Glassware
812:Autoclave
807:Aspirator
760:Incubator
694:Iron ring
617:Sonicator
587:Chemostat
529:Hot plate
331:from the
222:Expansion
216:Cryogenic
157:), whose
149:(such as
1650:Lab coat
1575:Tweezers
1565:Heat gun
1321:pH meter
1230:Bell jar
1110:Dropping
1064:Florence
1054:Fernbach
1016:Syracuse
875:Scoopula
825:Crucible
534:Lab oven
430:Fermilab
341:elevator
264:hydrogen
231:nitrogen
147:cryogens
1589:General
1509:Ammeter
1209:Thistle
1166:Pipette
1141:Cuvette
1131:Burette
1100:BĂĽchner
1093:Funnels
1079:Schlenk
1059:Fleaker
1039:BĂĽchner
960:Bottles
880:Spatula
870:Stopper
840:Forceps
740:Storage
657:Holders
577:Shakers
548:Striker
496:Heaters
483:General
291:1:1438
178:buckets
83:scholar
1623:Safety
1225:Beaker
1204:Thiele
1189:Cragie
1184:Drying
1105:Hirsch
1069:Retort
1031:Flasks
999:Dishes
990:Liebig
951:Kipp's
865:Splint
675:Tripod
653:Clamps
649:Stands
612:Shaker
574:Mixers
499:Dryers
329:oxygen
288:(LNe)
280:1:860
277:(LO2)
275:oxygen
269:1:851
266:(LH2)
258:1:847
255:(LAr)
247:1:757
244:(LHe)
242:helium
236:1:696
233:(LN2)
218:fluid
206:Safety
193:Design
182:vacuum
85:
78:
71:
64:
56:
1558:Tools
1176:Tubes
1011:Petri
408:(PDF)
253:argon
224:ratio
139:dewar
90:JSTOR
76:books
1240:Vial
1199:Test
835:File
539:Kiln
286:neon
62:news
333:air
322:ice
153:or
45:by
1795::
428:.
410:.
385:.
363:.
133:A
463:e
456:t
449:v
432:.
112:)
106:(
101:)
97:(
87:·
80:·
73:·
66:·
39:.
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