INSTRUMENT MANUAL
VACUUM GAUGE MODEL MM200
160Phone:(215) 947-2500 fax:(215) 947-7464 e-mail:[email protected] web site:www.televac.com
MM-200_im REV M
Page 156 of 160
TELEVAC
904
CLEANING COLD CATHODE GAUGE TUBES
Any cleaning schedule is dependent on cycle time/frequency and the degree of contaminants present in the
manufacturing process. Each facility should determine a schedule based on their own specific experience. When it
is established, the following cleaning procedure is recommended:
1.
Remove the sensor from the vacuum chamber.
2.
Unscrew the cap to expose the anode assembly (to remove, rotate cap counter clockwise).
3.
Gently lift the anode assembly upwards to separate it from the body.
4.
Remove the “o” ring from the body, being careful not to scratch the “o” ring seat. Wipe it off with a lint
free tissue making sure that it is still intact (no cracks or tears). It should be round and not flattened out.
5.
Blast the entire anode assembly at 30 psi using glass beads, being careful not to damage the glass
feedthrough. (If any rainbow effect is noticed, a possible crack in the feedthrough my exist and the
anode assembly may need to be replaced. P/N2-6200-37).
6.
Blast the body with glass beads concentrating on the pole piece and the “o” ring areas. Clean the
remaining internal parts. If the threaded end of the tube needs cleaning, it can be glass blasted as well.
7.
After cleaning, blow out any residual glass beads or dust with dry air. See that all metal particles are
removed from the pole piece areas.
8.
Re-grease the “o” ring with Apiezon L or M grease, (a vacuum approved grease).
DO NOT APPLY
EXCESS GREASE
. “o” ring should be shiny.
9.
Install “o” ring in body.
10.
Replace the anode assembly in the body after the “o” ring has been installed. Observe the keyway
location.
11.
Screw the cap on and hand tighten.
12.
Reinstall in the vacuum chamber.
13.
after the seal on threads has cured, allow 1 – 2 hours for the tube to degas when pumped down to high
vacuum.