Edwards B777-51-000, Инструкция по эксплуатации, Страница: 23 / 40

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Installation
B777-50-880 Issue D
3.5 Purge gas connection
3.5.1 Connect the purge gas
If supplying a purge gas to the pump, fit a vent port adaptor (see Section 7 ) in place of the purge port plug ( Figure 5 ,
item 4). Connect the gas supply to the purge port. The purge gas must comply with the specification given in
Section 2 .
Limit the purge gas flow rate to the allowed range, also specified in Section 2 . To limit the flow rate use a flow
controller or a pressure regulator and calibrated flow restrictor. The PRX10 purge restrictor accessory (see Section 7 )
is suitable for this purpose. Adjust the PRX10 as described in the instruction manual supplied with the accessory.
3.5.2 Recommended purge gas flow
The recommended minimum purge gas flow for typical applications is 25 sccm (0.42 mbar l s
-1
, 42 Pa l s
-1
). This flow
will protect the pump when pumping oxygen in concentrations above 20% by volume.
3.6 Electrical installation
Always make the electrical connections to the pump after the pump has been installed on the vacuum system.
The EXC controller provides the electrical supply to the EXT556H pump through the pump-to-controller cable.
Connect and lock the bayonet connectors at the ends of the cable to the mating connectors on the pump and the
EXC controller (if applicable).
The EXC controller is designed to allow a pumping system to be configured in a variety of ways, from a basic manually
operated system to a fully automatic system with remote control. Refer to the instruction manual supplied with the
controller to complete the electrical installation.
It is the responsibility of the customer to ensure the stability of the system and the correct application of all electrical
and vacuum connections. It is also the responsibility of the customer to ensure that no service connections present
slip or trip hazards.
WARNING
Electrically bond the EXT556H pump to earth (ground) using the earth (ground) screw provided on
the pump (item 5,
Figure 5 ) to ensure that the pump complies with EN61010.
WARNING
Do not remove the EXDC controller/EXC controller cable from the pump until the pump has come
to a complete halt. To do so would expose personnel to hazardous voltages and potentially damage
the EXDC/EXC controller.