LEYBOLD 230070V02, Руководство по эксплуатации

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33 300544652_002_C1 - 11/2016 - © Leybold
Maintenance
Transmitter failures due to contamination, as well as expendable parts (filament), are not covered by the warranty.
9.1
Cold cathode maintenance
When a cold cathode sensor is turned on and operated at pressures higher than 1E-
3 mbar the inside wall of the ionization chamber can be sputtered by ions formed by
the high energetic plasma. Inert gases like argon are easier to ionize and
consequently the sputter effect is more significant in such environment.
If the transmitter is contaminated, the pressure measurement will typical be lower
than actual pressure. Sputtering can also be visually detected since the inside wall of
the transmitter changes color. When operated in oil lubricated pumping systems,
hydrocarbons can cause contamination of cold cathode measuring cell.
If sputtering or contamination occurs, the cathode plates and anode ring can be
changed from the flanges side without disassembling the transmitter. The anode ring
and cathode plates are available as replacement parts (See chapter 2.3). The basic
accuracy of the cold cathode sensor can change after replacement of anode. The
anode ring and cathode plates can also be cleaned by mechanical polishing.
It is recommended to perform a zero adjustment after replacing or cleaning the cold
cathode parts to achieve the best measurement performance in the lowest part of
the measurement range.
Changing the cathode plates
1. Turn power off and remove cable.
2. Dismount the transmitter from the vacuum system.
3. Remove the clip ring (1) using a clip ring remove/insert tool.
4. Remove the front cathode plate (2).
5. Unscrew the Torx (T6) screw at the rear cathode plate (3).
6. Remove the rear cathode plate (3).
7. Insert the new rear cathode plate (3) (Do not touch by hand).
8. Insert the Torx (T6) screw (3) and tighten.
9. Insert the new front cathode plate (2).
10. Insert the clip ring (1).
Changing the anode
11. Remove the cathode plates (2,3) by following step 1 to 6 in the previous
guide.
12. Unscrew the 3 Torx (T6) screws at the anode module.
13. Remove the anode module and clean module or insert new.
14. Insert the anode module screw and DO NOT tighten. After all screws are
inserted carefully tighten the screw a little and move on to the next one.
Continue to tighten the screws one by one until all tight.
15. Perform leak testing of transmitter.
16. Insert the cathode plates by following step 7 to 10 in the previous guide.
Cleaning the cathode plates and anode
Contaminated parts can be cleaned by mechanical polishing or ultrasonic cleaned followed by alcohol degreasing
(e.g. Isopropanol). Make sure that all parts are clean and remove any discoloring of the stainless steel and titanium
parts. Alternatively the anode module or screens can be replaced with new parts.