Edwards nEXT240, Инструкция по эксплуатации

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B800-00-880 Issue A
Page 28 © Edwards Limited 2009. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Installation

If the pump has an ISO flange, use the Edwards combined inlet screen and trapped O-ring supplied with the
pump and use a minimum of four claw clamps (each torqued to 30 Nm) to connect the inlet-flange of the
pump to the vacuum system. Alternatively, use a rotatable collar and the combined inlet screen and trapped
O-ring supplied with the pump to connect the inlet-flange of the pump to the vacuum system; use a full
complement of bolts with the rotatable collar.
All inlet flange bolts must be re-tightened once the system is under vacuum. Ensure that no torques or other forces
are transmitted to the pump from the vacuum system or the associated pipelines. If necessary, fit an inlet vibration
damper between the pump inlet and the vacuum system (refer to
Section 7.4 ). In this case you must fix the base of
your pump to a firm support, as described in Section 3.3.4 .
3.3.4 Base mounting
The base of the nEXT pump can be fixed to a firm support using the tapped fixing holes. Refer to Figure 3, 4 and 5
for fixing hole details.
Note: The four rubber feet must be removed from the four tapped fixing holes before the pump can be base
mounted.
We advise the following requirements should be met to ensure the pump remains secure in the event of a total pump
seizure:
This method of fixing must be used if your pump supports the weight of the vacuum system. The weight of the vacuum
system must be no more than 20 kg.
3.3.5 Backing connection
CAUTION
Do not use the nEXT pumps with a backing pressure below 5 x 10
-4
mbar (5 x 10
-2
Pa). Lower backing pressures
will increase the evaporation rate of the lubricating oil and so may reduce the life of the bearings.
Use suitable vacuum tubing and connectors to connect the NW flange of the backing-port to your backing-pump. If
necessary, use flexible pipe or bellows to reduce the transmission of vibration from the backing-pump to the nEXT
pump.
We recommend that you use an Edwards EM, RV or XDS Scroll backing-pump. The recommended size of backing-pump
required is indicated in Table 4. A larger or smaller backing-pump may also be suitable, depending upon the
application it is intended for.
The nEXT pumps are suitable for use with diaphragm backing-pumps although the effect of higher backing pressure
on the pump's performance and cooling requirements should be noted. Refer to
Table 4 and Section 2.1 .
Support must withstand a destructive torque of: 6KNm
Fixing screws: M8 to ISO898-1 strength class 12.9
(nom. tensile strength 1200 MPa)
Screw engagement length: 6 mm minimum
Fastening torque: 15 Nm (1.53 kgf.m)
WARNING
Ensure safe ducting of the backing line if oil mist or hazardous substances are present.
WARNING
To avoid over pressurising the pump, the exhaust line should not be restricted when venting from
a positive pressure gas supply.