On Friday 30 December 2016 21:37:11 Jon Elson wrote: > On 12/30/2016 11:10 AM, Gene Heskett wrote: > > And I suppose the real schematic for that was top secret. > > No, this is a scientific research lab in the middle of a > college campus, no secrets. > But complexity? YIKES, they have it in spades. > > > AIUI, that warmup also damaged some of the magnets. Too fast. > > Since the cooldown had to be staged for the same reason, I assume > > they started with GN2, then LN2 a week later, etc etc. Then as fast > > as they could, evacuate the LN2 and switch to gaseous helium, > > gradually cooling it until they got to liquid. They would I assume > > do some gas separation with a big Cardox or similar to get rid of > > the residual nitrogen. A complex process to be sure. > > No, they have the design of supercon magnets down to a > science, so that they have few problems, nowadays. > But, you DO have to avoid a quench, where the magnet is > ramped up to field (and therefore contains enormous magnetic > energy) when the temperature rises. So, they had to have a > crew rush in and ramp the big magnets down before they > warmed above the critical temperature. They did manage to do > that. > > It did take several weeks to get the whole facility cooled > down again, after the leak was fixed and they obtained the > amount of helium to restart. Enough egg on everybody's face > to go around. > > Jon > But did they fix the problem? It seems to me that tracking the helium level in the system ought to be something a 6th grader watching mechanical gauges could do.
When I was in SoCal in 1959-60, one of the things I did for a few months was running the recorders that recorded the performance of the Ullage pressure regulators in the Atlas rocket, possibly even tested the units that gave john G. his first couple of rides. One of the things we had to do at the end of the shift was run the Cardox in the back yard to bring the helium recovery tank, a 50,000 cu ft rig that apparently leaked pretty badly, bringing it down to just a lb or so over ambient, and store the helium in a bank of about 25, 20 cu ft monel bottles, so they were, if we had enough to run the next day, about 7300 psi in them. Even in those bottles, they were down to around 5700 psi the next morning. We had about 3 deliveries a week from one of those trucks, which was about $12k a truckload. Boggled my mind that they really didn't shiv a git what it cost as it was a cost+ contract. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
