© Edwards Limited 2013. All rights reserved. Page 31
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Installation
B800-00-880 Issue D
3.3.1 Inlet screen (supplied fitted on CF only)
Remove the inlet screen only if there is no possibility that debris can fall into the pump. If the inlet screen is removed,
the pumping speed will increase by up to 10% for course and 20% for fine inlet screens. Since the screen protects the
pump from contamination, do not remove the inlet screen until the pump is mounted on the system.
To remove the inlet screen from a pump with CF inlet flange, use a bent wire hook or small screwdriver to carefully
lever the inlet screen out from the inlet flange.
To replace an inlet screen, locate it as centrally as possible over the CF inlet flange and then, with fingers applying
equal pressure around the edge of the screen, push it firmly downwards. If they are not already in place, the tangs
must be snapped into the locating groove in the inlet flange using a suitable tool to press them into position. For ISO
flanged pumps, Edwards supplies a combination inlet screen/trapped O-ring.
3.3.2 Mechanical fixing
There are two ways in which the nEXT pumps can be securely fixed. The ideal fixing for a nEXT pump is via its inlet
flange to a rigid, firmly fixed vacuum system - refer to Section 3.3.3. If this is not possible because of the nature of
the vacuum system, then the base of the pump must be fixed to a firm support. Refer to Section 3.3.4 for instructions
on base mounting the pump.
3.3.3 Inlet connection and orientation
The pump can be securely fixed to the vacuum system via the inlet flange. The pump can be mounted in any attitude
from the vertical and upright through to horizontal (± 2 °). If the pump is mounted horizontally and is used with a
rotary vane backing pump, ensure a foreline trap is installed to prevent condensed oil in the backing line from
entering the turbo pump. If it is not possible to fit a foreline trap, mount the pump with the backing port pointing
vertically downward (+/- 45 °).
Make sure that the pump inlet and all components fitted to the pump inlet are clean and dust-free. If the pump inlet
is not kept clean, the pump-down time may be increased.
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