Pre-Testing a Vacuum Diffusion Pump

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Joshua Guertler
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Real name: Joshua Guertler

Pre-Testing a Vacuum Diffusion Pump

Post by Joshua Guertler » Wed Jul 11, 2018 4:54 pm

Greetings fusor community,

I have recently purchased a MetroVac 033C diffusion pump off of EBay for a pretty fair price along with a 14 day return policy. Since this was an EBay product and had been noted to have some cosmetic wear, I was wondering if there would be a way to test the diffusion pump to make certain that it is fully functional without hooking it up to a fusor or other vacuum system.

If it helps, the diffusion pump has a heater and is water-cooled. thank you.

Joshua Guertler

Jake Wells
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Re: Pre-Testing a Vacuum Diffusion Pump

Post by Jake Wells » Wed Jul 11, 2018 5:21 pm

Use a multimeter to check the resistance of the diffusion pump heating coil. Diffusion pumps have no moving parts so it is hard to test them without hooking them to a vacuum system. This is all in the FAQ!
“The day science begins to study non-physical phenomena, it will make more progress in one decade than in all the previous centuries of its existence.”
― Nikola Tesla

Roberto Ferrari
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Re: Pre-Testing a Vacuum Diffusion Pump

Post by Roberto Ferrari » Wed Jul 11, 2018 5:25 pm

After checking electric resistance as suggested Jack, look for right insertion of the heater;
Check the flanges surfaces for no dents;
Check for no leaks of the main vessel ( water filling it in case has no oil on it).
Check water refrigeration circuit for no leaks or clogs and you are done.
Good luck,
Roberto

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Rich Feldman
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Location: Santa Clara County, CA, USA

Re: Pre-Testing a Vacuum Diffusion Pump

Post by Rich Feldman » Wed Jul 11, 2018 10:17 pm

There's an easy additional test, reported here by Muhammad Faizdul.
viewtopic.php?f=18&t=11088&p=73737

After cleaning the empty chamber, he filled it halfway with water and brought it to a boil. OP mentions one hazard.
boiler.PNG
Roberto already mentioned water filling as a way to detect gross leaks, without using vacuum.
A heater test by ohmeter (only) might miss things like mouse or spider nests in the bottom of the unit.
Richard Feldman

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