How to Rebuild a Plunger Pump

CAT PUMPS® demonstrates how to disassemble plunger pumps, inspect and repair the valves, seals, and plungers on plunger pumps, and reassemble plunger pumps on a variety of different models. This includes 3, 5, 7, 15, 25, and 35 frame plunger pumps. Different frames operate differently, however some pumps are similar enough that they've been grouped up for convenience. They are: 5, 7, and 15 frame plunger pumps at 0:00, 3 and 25 frame pumps at 13:17, and 35 frame pumps at 23:06.

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Plunger pumps are a type of positive displacement pump that use a plunger to move fluid through a cylindrical chamber. Plunger pumps do this by expanding and contracting a cavity in a reciprocating motion, opening and closing discharge and inlet valves at different times. The contraction of the cavity builds pressure, forcing fluid out the discharge valve.

Increasing the number of pump cylinders increases the capacity of the pump. Simplex pumps have one cylinder, Duplex have two, and Multiplex have any amount more than two.