Hi, Gene Heskett wrote: > Our std night shift procedure was to pump the big tank down to under 2 or 3 > psi, which put the bottles up around 7400 to 7800 psi at midnight. The > morning shift at 8AM had 5200 psi to play with till the truck got there. > Around a 2500 diff. Where did the rest of it go?
My bet is still on high-school thermodynamics. The pressure of a given amount of gas in a given volume is proportional to its absolute temperature. Pressure reduction from 7400 to 5200 would correspond to a temperature reduction from e.g. 427 Kelvin (309 F, more than boiling hot but not glowing) to 300 Kelvin (80 F, luke warm). Helium is known to heat up much during compression: https://www.bauercomp.com/products/helium "helium releases large amounts of heat when compressed, which the compressor must be able to absorb and shed." This diagram looks like it's getting really hot: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilp2QY9nqT0RsVCmojeGCq8gBn5XqUU_wdRex72kjNSWqe4BeXlbHhREPx-M-YrwAx3txSi16MX3IJgj5dh1dRJ5dKVunIFsVhieC-ioX35I9iT7qQm7PE1azs-jq_A43XlvYV4PfMXCw/s640/adiabatic+compression.png (I expect the compressor to have disposed a lot through its cooling rips.) In the bottles it has lots of surface per volume to dissipate heat over night. We should now discuss our options for building a time machine which can send an oven thermometer back to the 1960s. Have a nice day :) Thomas
