Matthew Karam wrote:

On Aug 18, 4:35 pm, (Samuel M. Goldwasser) wrote:

The only thought I have is that if the safety valve failed and the rotary
pump was running near 1 atm for many hours, it could have dumped nearly
all its oil out the exhaust. No problem with pump (or at least there
wasn't). Running with low oil probably didn't do it any good.



Hi Sam,

Thanks for the input. For all I know, the valve failed 5-minutes after
I left on Friday. The solenoid overheated and all the DC wires melted.
This opens a slow leak... not sure how long that "slow leak" takes to
reach 1 atm... but then the RVP ran like that for up to two days until
I noticed the puddle today.

Seems strange to me that this leak would take it even close to 1 atm
considering the RVP should take the system to 10^ -1 quickly and
easily.
I'll run it again and hopefully that fixes it.
The RVP wasn't making bad sounds today... so I presume it's ok. It
spit out a lot of oil mist when I first turned it on but that's to be
expected.

Bah, another $500 valve

Thanks,
-Matthew

Ah, I remember spending hours one Monday cleaning vacuum pump oil off of
EVERYTHING (e.g.: dielectric coated laser mirrors). Guano happens.

How about some sort of watchdog against future disaster? Perhaps a vacuum
sensor to initiate a delayed shut down of the rotary pump and some way to
gracefully leak the system up to atmosphere?