Product Introduction:
Helium molecular weight: 4.0026
Melting point (2555kPa): -272.1℃
Boiling point (101.325kPa): -268.94℃
Liquid density (4.20K, 100.312kPa): 125.2kg/m3
Helium density (0℃, 101.325kPa): -0.1785 kg/m3
Relative density (gas, 0℃, 101.325kPa): 0.138
Specific volume (21.1℃, 101.325kPa): 6.0304 m3/kg
Gas-liquid volume ratio (15℃, 100kPa): 748 L/L
Critical temperature: -268.0℃
Critical pressure: 229 kPa
Critical density: 69.3 kg/m3
Heat of fusion (1.2K, 2555kPa): 0.0836kJ/kg
Heat of vaporization (-268.926℃, 101.325kPa): 20.42 kJ/kg
Specific heat capacity (gas, 25℃, 101.325kPa): Cp=5238.3 J/(kg·K) Cv=3213.7J/(kg·K)
Specific heat ratio (gas, 25℃, 101.325kPa): Cp/Cv=1.63
Vapor pressure (0.5K): 0.0000022kPa (2.0K): 3.17kPa (5.0K): 197.1 kPa
Viscosity (0℃, 101.325kPa): 0.01864 mPa·S (liquid, 3.0K): 0.0033 mPa·S
Surface tension (4.2K): 0.096 mN/m
Thermal conductivity (0℃, 101.325kPa): 0.1426 W/(m·K) (liquid, 2.4K): 0.01883 W/(m·K)
Refractive index (gas, 0℃, 101.325kPa): 1.000035
Technical parameters:
| No. | Name | Chemical formula | Purity (%) | Pressure (Mpa) | Filling volume (m3/kg) | Valve thread outlet | Cylinder volume (L) |
| 1 | High purity helium | He | 99.999 | 13.5 | 5.5 | PX-32｜G5/8 | 40 |
| Composition | High purity helium | Unit | |
| Helium | ≥ | 99.999% | %V |
| Neon | ≤ | 4 | ppmv |
| Hydrogen | ≤ | 1 | ppmv |
| Oxygen | ≤ | 1 | ppmv |
| Nitrogen | ≤ | 2 | ppmv |
| Carbon monoxide | ≤ | 0.5 | ppmv |
| Carbon dioxide | ≤ | 0.5 | ppmv |
| Methane | ≤ | 0.5 | ppmv |
| Water | ≤ | 3 | ppmv |
