Edwards Vacuum Pump QDP40/QMB250

Release the NW40 clamp at the exhaust check-valve outlet flange and remove the check-valve from the system pipeline.

Unscrew the two halves of the check-valve body; use a strap wrench if necessary.

Remove the fluoroelastomer ball and the ‘O’ ring.

Use a cleaning solution suitable for the process products pumped to clean the valve body and the fluoroelastomer ball.

If necessary, replace the fluoroelastomer ball with a new one.

Use a suitable pump or syringe to suck the oil out of the gearbox

Discard the old bonded seal on the oil filler-plug

Replace with a new bonded seal from the pump maintenance kit

Fill the gearbox through the filler hole with the correct grade and quantity of oil

Allow the oil to drain into the gearbox and check the level on the oil sight-glass

Cooling-Water System Inspection

Inspect cooling-water connections and pipelines

Tighten any loose cooling-water connections

Repair or replace corroded or damaged cooling-water components

Seal any leaks in cooling-water system

Nitrogen Supply System Inspection

Inspect nitrogen supply connections and pipelines

Tighten any loose nitrogen supply connections

Repair or replace corroded or damaged nitrogen supply components

WARNING: Do not remove the oil filler-plug when the pump is operating.

Ensure the pump is not operating before proceeding.

Check the pump gearbox oil-level on the oil-level sight-glass.

Is the oil-level between the MIN and MAX marks?

If oil-level is above the MAX mark

Drain excess oil from the pump until the oil-level is correct.

If oil-level is below the MAX mark

Unscrew and remove the oil filler-plug (3).

Pour oil into the gearbox until the oil-level is at the MAX mark.

Release the NW40 clamps at the silencer inlet and outlet flanges to disconnect the silencer from the check-valve and the pump.

Slide the silencer out towards the high-vacuum end of the pump to remove the silencer from the pump.

Alternatively, undo the two support-plate retaining screws and slide the silencer complete with the support-plate towards the motor end of the pump.

Silencer Cleaning and Inspection

Remove and retain the six bolts and washers which secure each end-cover plate to the silencer body. Pull the end-cover plates squarely from the outlet pipe to remove them.

Remove the three ‘O’ rings from the silencer and discard.