vacuum test – 29 sept 2018

The devil is in the detail …

To test my pumping device, I use a vacuum chamber which has an internal volume of 5 liters in its complete configuration and 1.94 liters in the configuration used here, with only the lower part.

The lower part of the chamber is closed by an ISO-K 160 cover with a KF40 coupling for pumping

The automated pumping system in action

The test ended at night!

The pressure drops to 6.6 10-3 Torr with only the primary pump. It’s better than before !
With the Edwards EO40 / 55 DP1 diffusion pump the pressure drops to 4.34 10-5 Torr in one hour.
The closure of the chamber isolation valve causes the circuit pressure to drop to 2.19 10-5 Torr ( and then only the part of the circuit on the vacuum rack is pumped down), there is therefore a lot of work to do on outgassing and cleaning the vacuu chamber. 

note: the tests were conducted without greasing the joints with apiezon M

 

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