The HR3 is the cryogenic system recovery compressor and collects helium from the liquefier dewars, the roots pump, and the superconducting magnet and compresses it, and sends it to the two storage tanks outside.
There are two main components of the HR3 compressor:
1. QT portion (on top of Kaeser)
2. Kaeser compressor
QT portion of the HR3
HR3 control box: normal operation configuration (06/16/2023)
Normally opereration mode (06/16/2023)
| Valve | State |
|---|---|
| Vliq1 | Open |
| V19 | Closed |
| Vliq2 | Closed |
| V18 | This is a 3-way hand valve: position→ gas flow downwards |
| VEVAC | Close |
| V30 | Open |
| V35 | Open |
| VP | Close |
| V36 | Close |
| REGP | Open (fully) |
| V11 | Open |
| Vs4 | Close |
| Vfill | Close |
| Vmup | Close |
| V17 | Close |
| V14 | Open |
| NV2 | Close |
| SVPD | Always open (relay was taken out) |
| V12 | Close |
| V13 | Close |
| VDepr | Close |
| FI01 | Completely Opened |
| FI02 | Open (somewhere in the middle) |
| FI03 | Completely Closed |
| MV101-He | Open (from tank) |
| MV1020-He | Open (to tank) |
| MV103-He | Close |
The MV1 valve which is a red box in the back of HR3 will start blinking and close the main recovery path and then it forces helium gas through REG4 (making the horn sound). Closing this valve increases the pressure in the recovery manifold so that PC1 with a spike (usually just to 2 psi or so but less than 4 psi). Building pressure in this space pushes helium to the buffer tank through REG4 and REG3.
Recursive cycles in fault mode:
The Kaeser seems to have its own internal logic that is independent of the top QT ladder logic. The Kaeser run time is regulated by this internal logic under two modes Dual and Quadro. Quadro is the default mode (so anytime we lose power it will like come back in Quadro). The internal timing of these cycles is supposed to be settable in Quadro through the Kaeser interface but we could not find out how to do that. In Dual it's fixed. The HR3 part above the Kasser is also in 'idle' when not under load. It is in idle most of the time that we tried things no matter what the flow was.
When monitoring the reliving cycle on the QT part we noticed that SV7 appears to open only when there is a load (black arrow in Kaeser screen) for a very short time relieving pressure on the buffer tank and then returns to idle (white arrow in Kaeser screen). We then changed the 'Edit SV7 idle behavior' on the HR3 screen to "SV7 stays closed when compressor is in idle: NO". The default here is YES.
When this was done and the relay RL1 had the lever flip, the Kaeser relieving cycle that releases helium from the oil separator quit relieving. The other horn-sounding cycle on the HR3 continued but that one does not release any gHe so not a big concern that we know of.
We also switched the Kaeser from the default mode (Quadro) to the Dual. When we did this and switched the RL1 lever down the Kaeser relieving cycles also quit relieving. This is how we are running now, "Dual" with "SV7 stays closed when compressor is in idle: NO".
For the last 30 hours, HR3 seems to be running stably but it's not fixed. The repetitive horn-sounding cycles are happening about every 2-4 minutes. This does not seem to be harmful but it's not normal and an indication that something is wrong in the HR3 logic, or there is a bad sensor as part of the logic or some other issue that this cycle is trying to accommodate for by closing the main recovery flow path.
When we actually started trying to liquefy HR3 started running normally on its own. There may or may not be a correlation.
Kaeser Compressor
Kaeser Compressor Display (Click this link to see images)
Kaeser Compressor Maintenance