Edwards, nEXT Turbomolecular Pumps, nEXT240, nEXT300 and ...

B800-00-880 Issue B
3.3.1 Inlet-screen (supplied fitted on CF only)
WARNING
Removal of the inlet-screen will expose the risk of injury from sharp edges.
Do not remove the inlet-screen unless you can be sure that there is no danger 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.
Do not remove the inlet-screen until you are ready to mount the pump onto your system, since the screen protects
the pump from contamination.
Installation
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 your fingers
spread evenly 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 supply a combined inlet screen / trapped O-ring.
3.3.2 Mechanical fixing
WARNING
Do not operate the pump until it is securely fixed. If the pump seizes, the stored energy of the
rotor can cause rapid movement of the pump, which may cause further damage and injury to
people.
WARNING
The inlet screen is a coarse filter for debris and should not be used as a finger guard.
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
WARNING
Position system viewports and vulnerable components away from the pump inlet to safeguard
against damage from possible ejected parts in the unlikely event of a pump rotar failure.
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 you are using a
rotary vane pump to back your nEXT pump then the backing port must point vertically downwards (±20°) to reduce
the risk of contamination from the backing pump oil.
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.
The inlet connections for the nEXT pump are CF flange and the ISO flange:
• If the pump has a CF flange, use the copper compression gasket supplied with the pump and use a full
complement of bolts to connect the inlet-flange of the pump to the vacuum system.
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