6.1.2
Recommended purge method
Note:
To use the following procedure to purge the iL system, you must be able to introduce nitrogen
purge gas into the foreline without disconnecting any of the vacuum connections.
We recommend that you purge the iL system as described below before you do maintenance.
You must use this purge procedure if you have pumped dangerous substances, or if you think
that fluorinated materials in the pump may have overheated and undergone thermal
breakdown. This method of purge allows you to reduce the concentration of process gases in the
pump gearbox(es).
1.
Close any valves between the pump foreline and the process chamber and leave the iL
system open to the foreline.
2.
Start the LCDP pump (and on iL600 systems, the LCMB pump) and leave the iL system to
operate for five minutes.
3.
Shut down the iL system and leave it shut down for at least five minutes, to allow the
pressures in the pump and gearbox to equalise.
4.
With the LCDP pump (and on iL600 systems, the LCMB pump) stopped, purge the foreline
with nitrogen up to a pressure of 1 bar (1 x 10
5
Pa) for five minutes.
5.
The concentration of process gas in the gearbox(es) will then have been reduced by a factor of
4/Vf, where Vf is the volume of the foreline in litres.
Example
Suppose the foreline between the iL system and the tool isolation valve is made up of 10m of
ISO63 pipe. This foreline has an approximate volume of 30 litres.
To assume the worst case, suppose the initial concentration of process gases in the gearbox is
100%. After the first iteration of the purge procedure the concentration would be reduced to:
4/30 *100 = 13%.
If the acceptable level of contamination is 100ppm five iterations will be sufficient to achieve
a safe level. After five iterations the contration of process gas in the pump system would be:
(4/30)
5
* 100 = 0.004% = 42ppm.
6.
Repeat this procedure from Step 2 again until a safe concentration has been reached.
6.2
Correct use of Swagelok connectors
Note:
We recommend that you use a second spanner to hold the connector in position when you connect
or disconnect a Swagelok connector.
6.2.1
Fit the Swagelok connector
You must know how to correctly fit and tighten Swagelok connectors in order to prevent gas
leaks. Use the following procedure to fit the Swagelok connector:
(Continued on page 6-4)
6-2
iL Dry Pumping Systems
Содержание iL600
Страница 18: ...iL Dry Pumping Systems 1 9 Figure 1 3 Schematic diagram of the electrical system...
Страница 21: ...1 12 iL Dry Pumping Systems Figure 1 4 Services and electrical connections on the rear of the iL system...
Страница 23: ...1 14 iL Dry Pumping Systems Figure 1 5 Electrical components shown without enclosure for clarity...
Страница 71: ...3 28 iL Dry Pumping Systems...
