Estimate reading time: < 1 minute
I bought a used Edwards E2M5 vacuum pump for $150. I had thought the vacuum pump would be the most expensive part of the system, what a luck to find a pump for that price.. The only problem here is that after unpacking the pump from the box, I found a few drops of mercury spilled in the inlet port. So I examined the pump and realized that someone in the previous lab probably made a mistake and let the mercury get in the pump 🙁 I take it apart and caught all the drops I saw with the tin wire. When I assembled it back, I found one little rubber o-ring left 😉 I had to disassembly it again and then I found I had destroyed a large 44mm o-ring 🙁 Now I am waiting for new one from eBay. In the meantime, I got new oil, original Ultragrade 19.
I am still afraid of mercury vapours, I will probably place a hose on the outlet port and stick it out of the window..
The pump is able to achieve a 7.5×10-4 torr, reasonable minimum for the nixie tube before filling by gas. Alek is working with much higher vacuum, I don’t think that is necessary. The final pressure of the nixie should be (according to Alek) 20-30 torr after filling by gas.