Edwards E2M175

A366-04-880 Issue A
Page 18 © Edwards Limited 2014. All rights reserved.
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Operation
Use the following procedure to achieve ultimate vacuum:
1. Isolate the pump from your vacuum system.
2. Turn the gas-ballast control fully anti-clockwise (fully open) and operate the pump for at least 1 hour (or
overnight) to thoroughly purge the oil of contaminants.
3. Close the gas-ballast control.
4. Open the vacuum system isolation-valve and pump down to ultimate vacuum.
4.4 To pump condensable vapours
Use gas-ballast when there is a high proportion of condensable vapours in the process gases.
1. Close the vacuum system isolation valve.
2. Turn the gas-ballast control anti-clockwise to fully open and operate the pump for 30 minutes to warm the oil.
This will help to prevent vapour condensation in the pump.
3. Open the vacuum system isolation-valve and continue to operate the pump with the gas-ballast control open.
After you have pumped condensable vapours, you can (if necessary) decontaminate the oil. Use the procedure in
Section 4.5.
4.5 To decontaminate the oil
The oil in the pump should be clear. If the oil is cloudy or discoloured it is contaminated with process vapours.
1. Look at the condition of the oil in the sight-glass (Figure 1, item 9). If the oil is cloudy or discoloured, continue
with the procedure at Step 2 below.
2. Close the vacuum system isolation-valve.
3. Turn the gas-ballast control fully anti-clockwise.
4. Operate the pump until the oil is clear.
4.6 Unattended operation
The pump is designed for unattended operation under the normal operating conditions specified in Section 2.
However, we recommend that you check the pump at a regular interval of not more than 14 days. Check the pump
more frequently if you pump high volumes of gas or if you operate the pump with the gas-ballast control open.
4.7 Shut-down
Note: If the gas-ballast control is open and the pump is switched off for any reason, the pump drive shaft may
rotate in the reverse direction, causing a system pressure rise. To prevent this, use a gas-ballast control
valve (refer to Section 7.4.8).
We recommend that you decontaminate the oil before you shut down the pump. Decontamination of the oil will
prevent damage to the pump by the contaminants in the oil.
1. Refer to Section 4.5 and decontaminate the oil, as required.
2. Close the vacuum system isolation-valve (if not already closed).
3. Turn gas-ballast control clockwise to close.
4. Switch off the electrical supply to the pump.
5. Close the cooling water supply valve.