Port plates and distribution discs

What it does inside the pump

The port plate is the flat disc between the impeller face and the head. Its two kidney-shaped openings are the suction and discharge ports, and their angular position sets the timing — the point in the rotation where a cell opens to suction and where it opens to discharge. This is the part that makes a liquid ring pump a pump rather than a stirrer. It is fitted on flat-port machines: 2BE, 2BV, NEV2, SK, SX and similar.

How it fails, and what you see first

Port plates fail by face wear, and face wear opens the axial clearance between plate and impeller. Gas then leaks backwards from the discharge port to the suction port inside the machine, and ultimate vacuum degrades steadily with no change in noise or current — which is why this is the part most often missed during troubleshooting. The discharge-port edge also washes out when liquid is carried over, because liquid is not compressible and gets forced through that edge at high velocity.

What to send us so the part is right

Model, serial, and the current plate thickness measured at three points. Photograph the port face flat-on so we can see port geometry and the direction of rotation. State whether your machine has one port plate or two (most two-stage flat-port machines have one per stage). Cone machines (AT, TC, CL, 2SK) do not use a port plate — they use a cone.

Which models take this part (156)

Grouped by pump family. Model numbers in blue have their own page with the full specification table; the rest are supplied from the same frame — send the model and we confirm against the drawing.

Part numbers we have supplied for this item

Other parts for the same machine

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