The lubricator provides a pressure-tight grease seal in the stuffing box. See rod-transfer equipment . It contains space for storage and well-control equipment. Several rods screwed together make up the mechanical link from the beam pumping unit on the surface to the sucker rod pump at the bottom of a well. Sucker rods are threaded on each end and manufactured to dimension standards and metal specifications set by the petroleum industry.
Basic components are barrel, plunger, valves, and hold-down.
Two types of sucker rod pumps are the tubing pump, in which the barrel is attached to the tubing, and the rod, or insert, pump, which is run into the well as a complete unit. See suction tank. Also called a suction pit. Some states require a minimum length to protect freshwater sands. Compare conductor pipe.