Edwards Vacuum Pump QDP80/QMB250

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 Inspection and Cleaning

Empty all loose deposits from the silencer body; take care not to damage the end-cover plate sealing surfaces.

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

Ensure all necessary tools and materials are available (screwdriver, lint-free cloth, PFPE grease, new 'O' ring).

Ensure the pump is turned off and cooled down before starting the procedure.

Remove the six screws securing the bearing end-cover to the high vacuum head-plate.

Lift away the end-cover and remove the sealing ‘O’ ring.

Use a clean lint-free cloth or a plastic or wooden spatula to remove old grease from the end-cover and bearings.

Ensure substances do not contact skin or eyes

Avoid inhaling vapours from substances

Fit blanking caps to inlet and outlet flanges when moving the check-valve

Valve Removal and Inspection Preparation

Ensure exhaust-silencer is disconnected from the pump

Ensure exhaust check-valve is removed from the system

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