© Edwards Limited 2008. All rights reserved.
Page 25
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Operation
B722-20-880 Issue D
4
Operation
Note:
The following sections describe the use of the EXT pump in a basic, manually-controlled pumping system
with a manual vent-valve, and with an EXDC drive module. Refer to the EXDC drive module instruction
manual for full details of installation and electrical connection.
4.1
Start-up
1. Turn the manual vent-valve clockwise to close it.
2. Turn on the cooling-water supply (if water-cooling is used) or fan (if air cooling is used).
3. Start the backing-pump.
4. Start the EXT pump by supplying power to the EXDC drive module (see EXDC instruction manual).
Note:
For large vacuum systems (100 litres or larger) wait until the system pressure reaches 10 mbar (1 x 10
3
Pa)
before supplying power to the EXDC drive module.
5. The pump will then accelerate to normal operating speed. When this has been reached, the green LED on the
EXDC will light.
Note:
The first time you pump down the system to vacuum, you must re-tighten the bolts which secure the
inlet-flange: refer to
.
4.2
Shut-down
Note:
In an emergency only, open the vent-valve quickly to decelerate the pump rotor in the shortest possible
time.
1. Switch off the backing-pump and stop the power to the EXDC drive module (see EXDC instruction manual) to
switch off the EXT pump.
2. When the EXT pump rotational speed has fallen to below 50% of full rotational speed, you may turn the manual
vent-valve anticlockwise to open it. Ensure that the rate of pressure rise does not exceed the allowed rate of
pressure rise, otherwise the pump may be damaged: refer to
and
3. If water-cooling is in use, turn off the cooling-water supply.
WARNING
Do not operate the pump unless it is connected to your vacuum system. If you do, the pump rotor
can cause injury. The pump rotor rotates at very high speeds and you may not be able to see that
the pump is rotating. Always ensure the pump has stopped rotating before removing it from the
vacuum system.
WARNING
Do not expose any part of your body to vacuum. If you do, you may be injured.
