Sucker rod

A sucker rod is a steel rod, typically between 7 and 9 metres (25 and 30 ft) in length, and threaded at both ends, used in the oil industry to join together the surface and downhole components of a reciprocating piston pump installed in an oil well.

Sucker rods are also commonly available made of fiberglass in 37 1/2 foot lengths and diameters of 3/4, 7/8, 1, and 1 1/4 inch.

The surface unit transfers energy for pumping the well from the prime-mover to the sucker rod string.

The horse head and bridle are used to ensure that the pull on the sucker rod string is vertical at all times so that no bearing movement is applied to that part of the sucker rod string above the stuffing box.

The polished rod and stuffing box combination is used to maintain a good liquid seal at the surface.

The line of sucker rods is represented in this diagram by the solid black line in the center of the well