2018/10/22 (Monday)
| status: | Warming up. Mixture in dump. LN2 traps are warm and still have contaminants in them. 1K Pot needle valve open. Around 1 bar N2 in IVC. |
|---|---|
| 1200 | MC(Cernox) = 290.0 K. IVC = 0.87 bar. |
| on 2018/10/21 12:00, MC(Cernox) = 287.9 K | |
| 1205 | Recovery meter seems to have completely stopped increasing, or maybe has gone very slightly backward. Close valve from MB to recovery. Helium gas recovery meter: 229723.57 ft^3 |
| Studying LHe recovery versus main bath level, there's now strong evidence that the 1K Pot is responsible for our low recovery efficiency. The 1K Pot exhaust is connected to an oil mist eliminator, then there's a tee to an overpressure relief valve (which was removed some months ago), then a hose runs to a valve which allows selection of exhaust to recovery, then it runs to the recovery system, with an additional closeoff valve, then piping to the meter (which does not go through the copper warming coil). Inspecting the oil mist eliminator we found the the cartridge is saturated(clogged) with oil and needs replacing. We found a replacement in the cabinet. |
| Here's a manual for the Alcatel OME 25 S oil mist eliminator There is a 375 Torr (7.25 PSI) safety valve that should release the outlet pressure to the exhaust in the case that the cartridge is saturated. If instead the outlet gas leaks out the seals rather than opening the valve, we could be losing the recovered gas. |