Helium compression

Table 7. Selected Commercial Specifications for Helium Compressed Gas Association Grades ...

Synonyms Helium, compressed Helium, refrigerated liquid (cryogenic liquid)... 

Synonyms cas 7440-59-7 helium, compressed (dot) helium, refrigerated liquid [Pg.156]

In order to clear place for the installation of components of the new ventilation system and other systems, the components for high-purity helium compression and storage had to be dismantled. More than 90% of the metal were unconditionally released as iron scrap. 

DOT Label NON-FLAMMABLE GAS TC Shipping Name Helium, compressed... 

Figure 4.37. Contraction of 0.4-mm-thick primary and secondary coatings in film form during cooling from 100 °C at 4 °C/min in helium (compression mode, 0.1 g on a 3-mm-diameter probe (141 Pa pressure) in helium arrows depict the onset and end of each glass transition (Bair, unpublished, 1998).

CGA P-9, The Inert Gases—Argon, Nitrogen and Helium, Compressed Gas Association, Inc., 1235 Jefferson Davis Highway, Arlington, VA 22202. 

The work for this system with 100% effective heat exchangers was calculated earlier in part (a) as 10,447 kJ/kg of helium compressed. The incremental work needed to overcome the ineffectiveness of the heat exchangers must be added to this value for a total of 10,547 kJ/kg of helium compressed. The COP for this modified system is then... 

Helium gas in a Collins liquefier is compressed isothermally and reversibly from 0.101 MPa and 300 K to 1.41 MPa. After cooling this compressed gas to 60 K, 25% of the gas is expanded in the first expander to 0.101 MPa. The remaining gas is further cooled to 15 K where 50% of the original compressed gas is expanded in a second expander to 0.101 MPa. If both expanders operate adiabatically and reversibly, determine the liquid yield, work required per unit mass of helium compressed, work required per unit mass of helium liquefied, and the figure of merit, assuming that the expander work is dissipated externally. Determine these same quantities when the expanders have a thermodynamic efficiency of 70% and the compressor has an overall efficiency of 75%. 

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