B344-21-880 Issue N
Page 40 © Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Maintenance
5.5.5 Inspect and clean the interior
When you clean the pump, choose the cleaning solution to suit the type of pump fluid that has been used. The jet
assembly can be vapour de-greased.
1. Inspect the pump interior. If there is a solid deposit of pump fluid around the base, do not attempt to remove
the deposit mechanically as this is likely to damage the pump; instead, attempt to remove the deposit with an
ultrasonic cleaning bath.
2. Wash the interior of the pump and the pump interior components with the selected cleaning solution.
3. Wash again with acetone to remove all traces of the solution. Bake to 77
o
C to remove the acetone.
Alternatively, pass warm air over the components and the pump interior.
4. Check that all sealing-faces are scratch-free. Refinish surfaces that are scratched.
5.5.6 Reassemble the pump
1. Insert the jet assembly in the pump-body and position it on the base; align the ejector jet with the backing tube
and the slot in the base of the jet assembly with the drain-tube extension.
2. Position the spring on the top-jet cap.
3. Ease the water-cooled baffle-cap through the valve bore to insert it in the pump. Assemble the baffle-cap and
the retaining strap, then secure the strap:
z On Diffstak 63/150 pumps: the baffle-cap strap is secured by one screw at the centre of the strap.
z On Diffstak 100/300, 160/700 and 250/2000 pumps: the baffle-cap strap is secured by two screws.
4. To refit a manually-operated high-vacuum isolation-valve, carefully insert the valve-shaft in the valve-body and
fit the valve-plate and the screws. Do not tighten the screws fully (lubricate seals and bearings as described in
Section 5.7). Open and close the valve slowly a few times to ensure the valve-plate is centrally positioned on the
shaft, then, with the valve in the fully closed position, tighten the screws securely.
(Continued on page 42)
Remove all traces of the cleaning solution before you operate the pump.
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