REAR HEADPLATE SPARE EH250/500

Edwards EH250 or EH500 pump is a Roots vacuum booster . Inside, there are two figure-eight shaped rotors. They spin inside a figure-eight shaped housing.

The housing is open on both ends. Those open ends need to be closed off. That is what the headplates do.

There are two headplates on every EH pump:

• Front headplate – closes the end near the drive motor

• Rear headplate – closes the opposite end (this is the one we are talking about)

Each headplate has several important jobs:

• Seals the pump: It keeps air from leaking in or out .

• Holds bearings: The rotor shafts spin on bearings mounted inside the headplates.

• Holds shaft seals: Special seals prevent oil from leaking out along the shafts.

• Provides mounting points: Other parts bolt onto the headplate.