Notes from the Purifier Vacuum Jacket Pump Out on 7,8-November-2023 -------------------------------------- The previous Purifier pump out was on 5,6-August-23 so this run was for only about 92 days. When this system was new we had runs of 120 to 130 days. The vacuum jacket was clearly in need of a pump out. When in Mode 41 the Trap Temperature was up to 71 or 72 k. On its last transition from Mode 42 to Mode 41 it took over 2 days of repeated attempts - all Friday and Saturday Nov 3 & 4. This was a serious risk because we had 300 psi in the Recovery Tanks. Chronology of this Purifier Vacuum Jacket Pump Out: 15:25 Set the Purifier to use a 24 Hr Regenerate cycle 7Nov23 when the Purifier goes into the Regenerate Mode. See notes below. The Pump Cart is connected to the Vacuum Jacket's Pump Out Ports but the Ports are NOT open yet. The rough pump is pumping on the vacuum lines that run to the Ports. 15:30 Was in Mode 41 with Temps 115 k - 72 k and 16 psi - 7Nov23 16 psi i.e. it was almost out of gas to purify. We had about 102.3 L in the Liquefier. Switch to Mode 51 - "Warm-Up Trap to Regenerate" mode. See notes below. OPEN both of the Pump Out Ports. When the vacuum in the pump cart vacuum manifold falls below 1.0 E-1 start the turbo pump. 15:55 In Mode 51. External Heater set to 50 Volts on 7Nov23 its variac. 193 k - 258 k - 36 psi - 38 psi. Note how fast the parts internal to the vacuum jacket are warming up. They warm up this fast because the Internal Heaters are both ON (the Trap Heater and the Heat Exchanger Heater) and because the External Heater is ON. The outside of the vacuum jacket is warm to the touch not hot to the touch. Vacuum Cart Readings: Turbo Vacuum Turbo Outlet Manifold Input Sensor #1 Sensor #5 Sensor #6 Pirani Pirani Ion --------- --------- --------- 8.1 E-3 9.3 E-4 4.1 E-5 Torr 17:30 In Mode 71 - "Pumping Cold Trap" mode. 7Nov23 External Heater is set to 50 Volts. 284 k - 294 k - -14 psi - -14 psi The pressures shown on the Purifier's LCD display show a vacuum because the Cold Trap is being pumped by the dry pump that is built into the Purifier. Vacuum Cart Readings: 5.1 E-3 8.0 E-4 5.9 E-6 Torr ------ 9:05 In Mode 71 - "Pumping Cold Trap" mode. 8Nov23 External Heater is set to 50 Volts. 295 k - 293 k - -14 psi - -14 psi Vacuum Cart Readings: 4.3 E-3 8.0 E-4 1.9 E-6 Torr 9:10 Was in Mode 71. 8Nov23 Close both Vacuum Jacket Pump Out Ports. Set to the normal 30 Minute Regenerate Cycle. See notes below. Tap LCD Screen ON wait a few seconds and then tap ON a second time. See notes below. Now in Mode 11 - "Cool Down". 9:12 In Mode 11 - "Cool Down". 8Nov23 295 k - 286 k - 15 psi - 15 psi Note that the Cold Trap temperature has already started to fall. The system only filled to 15 psi (instead of the normal 32 psi) because the Recovery Tanks are still almost empty (the tanks are at 18 psi or something like that). Now watch the Cool Down to see how fast it goes. 9:45 Mode 11 283 k - 247 k - 15 psi - 15 psi 11:00 Mode 11 248 k - 191 k - 33 psi - 33 psi Note in the past hour the Recovery Bag was pumped into the Recovery Tanks which brought the Recovery Tanks up to about 62 psi which filled the Purifier to its normal operating pressure. 12:00 Mode 11 223 k - 152 k - 33 psi - 33 psi 13:00 Mode 11 201 k - 115 k - 33 psi - 33 psi 14:00 Mode 21 176 k - 85 k - 33 psi - 33 psi Note now in Mode 21 - the second step of "Cool Down". It has taken about 4 hours and 50 minutes to cool the Trap from 293 k down to 85 k. 15:00 Mode 35 111 k - 66 k - 32 psi - 31 psi Now in Mode 35 - "Transition to Steady State Purification - Purge Only". It is cold enough to be running but it probably thinks that it needs to Purge, i.e. to flow gas through the Purifier and dump it back into the Bag to clean things up before sending gas to the Liguefier. 16:00 Mode 35 91 k - 52 k - 32 psi - 31 psi Still in Mode 35 and it is now really cold. Tap the LCD Screen ON button again to see if that will get it to move on through its start up steps. 17:30 Mode 31 78 k - 45 k - 32 psi - 31 psi Now in Mode 31 - "Transition to Steady State Purification - Start Sensor" (yes, in their mindless control software Mode 31 can sometimes come after Mode 35). It is now really cold. The Purity Sensor is trying to start. 18:00 Mode 41 68 k - 57 k - 36 psi - 36 psi Finally in Mode 41 - "Steady State Purification". Waiting for the Liquefier to start taking gas from the Purifier. I assume that the 4 psi over pressure is because the Trap Temperature Control Servo Loop has just now come ON and warmed the Trap up to its normal 57 k but the Liquefier is not yet taking gas. Need to look up the Helium PT curve. 18:20 Mode 41 68 k - 57 k - 31 psi - 31 psi Temperatures and Pressures are stable and the Liquefier is running and taking gas from the Purifier. Note that there has been about 3 hours of thrashing around, after the Purifier was fully cold, before it actually start running and delivering gas. In my experience this is about normal - but probably mostly unnecessary and probably due to their mindless control software. Notes on Using the LCD Screen to: --------------------------------- - To switch to the Extended 24 Hour Regenerate Cycle: On the LCD Screen Tap: Menu (upper left-hand corner) ---> Control ---> Advanced ---> Extended Pump ON then tap Menu ---> Home - To switch back to the Normal 30 Minute Regenerate Cycle: On the LCD Screen Tap: Menu ---> Control ---> Advanced ---> Extended Pump OFF then tap Menu ---> Home Note that for normal Liquefier operation you must have the Purifier to be set for Normal 30 Minute Regenerate Cycles. - To switch the Purifier into its Regenerate Mode so that it will turn ON its Internal Heaters to warm up the parts internal to its vacuum jacket (i.e. the Cold Trap and Heat Exchanger) and then once these parts are warm to pump the water, nitrogen and junk out of its Cold Trap by running its built in dry pump - just tap the Regenerate button along the right-hand edge of the LCD Screen. - To switch the Purifier out of the Regenerate Mode and back into its normal set of operation modes just tap the ON button along the right-hand edge of the LCD Screen. Note that it seems that I normally need to tap the ON button twice (spaced a few seconds apart) to get the Purifier to actually fully quit the Regenerate cycle and return to normal operation. Note that you need to first put the Purifier back into its Normal 30 Minute Regenerate cycle mode and then tap the ON button (twice). Note You need to watch the Purifier to verify that it is really back to normal operation and running through its normal set of modes to deliver clean gas to the Liquefier. I have seen it behave in flaky ways when trying to get it back to normal operation. At times I thought that getting it fully back to normal operation required an additional tap or two of the ON button (or else it would just finally decided by itself to start operating normally - I'm not sure which).