Rotational power is supplied to the mud pump through an external power source. The power end of the pump converts this rotational energy through a crankshaft to a reciprocating motion that moves the pistons. The pistons move back and forth in their liners, exerting a force on the cylinder chamber.
A mud pump or drilling mud pump is used to circulate drilling mud on a drilling rig at high pressure. The mud is circulated down through the drill string, and back through the annulus at high pressures. Mud pumps are typically positive displacement pumps, otherwise known as reciprocating pumps.