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Liquid helium
Liquid helium is inert, colorless, odorless, non-corrosive, extremely
cold, and nonflammable. Helium will not react with other elements or
compounds under ordinary conditions. Since helium is non-corrosive,
special materials of construction are not required. However, materials
must be suitable for use at the extremely low temperatures of liquid
helium. Vessels and piping should be designed to American Society of
Mechanical Engineers (ASME) specifications or the Department of
Transportation (DOT) codes for the anticipated pressures and
temperatures.
Physical Properties
• Molecular Symbol: He
• Molecular Weight: 4.003
• Boiling Point @ 1 atm: -452.1°F (-268.9°C, 4oK)
• Freezing Point @ 367 psia: -459.7°F (-272.2°C, 0oK)
• Critical Temperature: -450.3°F (-268.0°C)
• Critical Pressure 33.0 psia: (2.26 atm)
• Density, Liquid @ B.P., 1 atm: 7.798 lb./cu.ft.
• Density, Gas @ 32°F (0°C), 1 atm: 0.0103 lb./cu.ft.
• Specific Gravity, Gas (Air = 1) @ 32°F (0°C), 1 atm: 0.138
• Specific c Gravity, Liquid @ B.P., 1 atm: 0.125
• Specific c Volume @ 32°F (0°C), 1 atm: 89.77 cu.ft./lb.
• Specific c Volume @ 68°F (20°C), 1 atm: 96.67 cu.ft./lb.
• Latent Heat of Vaporization: 34.9 Btu/lb. mole
• Expansion Ratio, Liquid to Gas, B.P. to 32°F (0°C): 1 to 754
Additional tables
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