Operation of a Reciprocating Pump

In the following paragraphs we describe key elements relating to operation of a common reciprocating pump.

a. The prime mover shaft is rotated by the prime mover, for example, an electric motor. Therefore, the prime mover shaft rotates in its centered position. This diagram shows the end-view of the prime mover shaft - therefore it looks like a circle.

b. An eccentric is mounted on the prime mover shaft. As shown, the eccentric is mounted eccentrically - that means that the center lines of the eccentric and the prime mover shaft do not coincide. This causes the eccentric to rotate around the prime mover shaft's center line. A connecting rod is connected to the eccentric. The circular motion of the eccentric causes the connecting rod to move to and fro. This is how we convert circular motion into lateral motion.