A705-74-880 Issue K
Page 24 © Edwards Limited 2009. All rights reserved.
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INSTALLATION
3.10.2 Connect the shaft-seals purge air or nitrogen supply
Your compressed air or nitrogen supply pressure must comply with the requirements of Section 2.2. If it does
not, the shaft-seals purge pipeline may become over-pressurised and the shaft-seals may fail.
Ensure that the compressed air or nitrogen gas supply must be clean and dry.
We recommend the installation of suitable non-relieving regulator pressure control devices, a pressure gauge, and
an automatically operated isolation-valve in your compressed air or nitrogen supply so that:
The shaft-seals purge air or nitrogen supply is on whenever the pump is on.
If you connect a nitrogen supply, the nitrogen supply is off whenever the pump is off.
Whenever the shaft-seals purge air or nitrogen supply is on, you must maintain the pressure to the shaft-
seals as specified in Section 2.2.
Use the following procedure to connect your shaft-seals purge air or nitrogen supply; A rigid metal (such as stainless
steel) pipeline with an outside diameter of ¼" (6.4mm) must be fitted for the air or nitrogen supply pipeline.
1. Refer to Figure 1. Remove the red blanking cap from the shaft-seals purge inlet (31).
2. Remove the ¼" (6.4mm ) compression nut and ferrule from the fittings kit and fit them finger-tight onto the
shaft-seals purge inlet connection (31).
3. Fit the end of the air or nitrogen supply pipeline to the shaft-seals purge inlet connection (31), then tighten the
nut to secure the pipeline in place.
3.10.3 Connect a nitrogen gas-ballast supply (optional)
To enable connection to the flow valve the nitrogen supply pipeline must terminate in a KF16 fitting.
If required a non venting (to atmosphere) nitrogen gas-ballast supply to the pump can be connected. The supply
should be set to shaft seal purge pressure. A non-venting (to atmosphere) nitrogen gas-ballast supply to the pump
must be connected if you pump dangerous gases.
When connecting a nitrogen supply to the gas-ballast system, it is recommend that you incorporate a suitable non-
relieving pressure gauge in the nitrogen supply pipeline.
Refer to Figure 8. Use the following procedure to connect a nitrogen supply to the gas-ballast system:
1. Undo and remove the clamp (9) and the NW16 trapped O-ring (10) and remove the air filter (11).
2. Use the clamp (9) and trapped O-ring (10) to connect your nitrogen supply pipeline to the gas-ballast flow valve
(8).
If Hazardous gases are to be pumped, fit a suitable non-venting (to atmosphere) nitrogen supply to
the shaft-seals purge inlet, to prevent the escape of dangerous gases from the pump.
If hazardous gases are to be pumped, fit a suitable non-venting (to atmosphere) nitrogen supply to
the gas-ballast system, to prevent the escape of dangerous gases from the pump.
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