BOC Edwards A730-01-983, Инструкция по эксплуатации, Страница: 21 / 44

Nov 02 Issue A
XDS Dry Pump
OPERATION
PAGE
15
15
4 OPERATION
4.1 Use of gas ballast control
You can use the gas ballast control to optimise the
performance of the scroll pump for your application.
The performance characteristics of the pump with
the different ballast settings are shown in
Section 2.2.2. You can change the position of the gas
ballast control when the pump is off or when the
pump is operating.
4.1.1 Gas ballast control
Use the gas ballast control to change the amount of
air introduced into the final stage of the pump. Use
of gas ballast will reduce the condensation of
vapours in the pump; the condensates would
contaminate the pump. You can turn the gas ballast
control to select one of the three positions, as
follows:
To select no gas ballast, turn the control position to
'0'. Use this setting:
• to achieve ultimate vacuum
• to pump dry gases.
To select low flow gas ballast, turn the control to
position 'I'. Use this setting:
• to pump low concentrations of condensable
vapours
• to decontaminate the pump.
To select high flow gas ballast, turn the control to
position 'II'. Use this setting:
• to pump high concentrations of condensable
vapours
• to clear excess vapours after processing.
4.2 Start up procedure
Use the procedure below to start up the pump:
1. Ensure that any vacuum system isolation valve is
closed (if fitted).
2. Connect a suitable lead from the power supply
to the electrical socket at the side of the pump.
3. Switch on the electrical supply to the pump,
using the on / off switch on the motor.
4. Always use the on / off switch to start / stop the
pump.
5. Open the vacuum system isolation valve (if
fitted).
4.3 To achieve ultimate vacuum
In order to achieve the best possible vacuum, the
pump should be operated with the gas ballast
control on position '0'. However, if the pump, or
elements of the vacuum system it is attached to, are
new or have been newly fitted, some atmospheric
moisture may be present. If atmospheric moisture is
present, run the pump with the gas ballast control in
position 'I' or 'II' for 20 minutes before switching to
position '0'. If moisture is allowed to remain, the
performance of the pump will be impaired.
WARNING
Ensure that your system design does
not allow the exhaust pipeline to
become blocked.
CAUTION
A fine black dust may be emitted from the exhaust
of the scroll pump during start up, particularly
when the pump is new or if new tip seals are fitted.
Refer to Section 5.6 for further information when
fitting new tip seals.