Foreline pump base pressure degraded

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Richard Hull
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Re: Foreline pump base pressure degraded

Post by Richard Hull »

You method is good and how I do it. I valve off the fusor chamber to diff pump inlet. (fusor left under vacuum. I then turn off the boiler in the diff pump and monitor the diff pump boiler temp until it drops to below 80 deg C, then I valve off the diff pump outlet to the mechanical pump inlet. (diff pump left isolated and under vacuum. Last I turn off the mechanical rotary pump and immediately un-clamp the hose to the mechanical pump and foreline. I let the foreline and mechanical pump up to air for 1 second (woosh!) then immediately re-clamp the foreline to pump.

I also have a ball valve on the mechanical pump's outlet. I immediately close this valve so that no air can enter the turned off rotary mechanical pump until the next time I use it.

Naturally, the first action on any restart is to open this ball valve to allow the rotary to exhaust properly while running.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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