Abstract: Progressive cavity (PC) pump drive heads require a stuffing box to seal crude oil from leaking onto the ground where the polish rod passes from the crude oil passage in the wellhead to the drive head. Because crude oil typically contains fine sand particles, alignment between the stuffing box and the polished rod is imperfect, and PC drive heads run continuously, it is very difficult make stuffing boxes that last as long as desirable by oil production companies. By using a flexibly mounted standpipe in various configurations, around which is a bearing supported shaft carrying the sealing means, long term durability of the stuffing box can be achieved. By using a pressurization system such that the pressure output exceeds the pressure at the wellhead, stuffing box seal life can be extended and external leakage from the stuffing box can be eliminated. A double wall standpipe may be provided in some applications as part of the pressurization system.

Abstract: A pump drive head backspin retarder includes a vane pump having an impeller with a plurality of spring loaded vanes and a pawl clutch centrally disposed in the impeller and having a hub and a plurality of pawls. Each pawl is pivotally attached to the hub for movement between first and second positions. The impeller includes a plurality of pawl receiving recesses, whereby, for a first direction of rotation, pawls of the pawl clutch pivot to the first position corresponding to a disengaged state for providing no mechanical contact with the impeller and, for a second direction of rotation opposite the first, pawls of the pawl clutch pivot to the second position due to inertia corresponding to an engaged state thereby engaging corresponding pawl receiving recesses.

Abstract: A right angle drive adapter for use with an oil well vertical drive head having a drive head housing and an input shaft rotatably mounted in and extending axially outwardly of the drive head housing. The adapter comprises an adapter housing removably securable to the drive head housing in axial alignment therewith, an input shaft mounted in the adapter housing for rotation therein and for removable attachment to a rotary source of power, an output shaft mounted in the adapter housing for rotation therein at substantially a right angle to the input shaft, the output shaft having a socket for telescopically receiving and drivingly connecting to the drive head input shaft; and a gearset mounted in the housing for drivingly connecting the input and output shafts. The adapter allows the installation of a vertical drive head and a gas engine to be used for driving the drive head before electrical power is available.

Abstract: A pump drive head includes a housing, and a main shaft carried on upper and lower bearings disposed in the housing. The main shaft includes an outer torque tube and a liner tube. The outer and liner tubes abut along a first portion of their length and are separated along a second portion of their length forming a double wall with an elongate tubular space in between. A standpipe is coupled at one end to the housing, below the lower bearing, and received by the elongate tubular space an eliminates the need for a lower seal on the main shaft. A hydraulic pump includes a hydraulic pump chamber displosed in the housing and communicating with the main shaft, and first and second gears disposed in the hydraulic pump chamber and the first gear coupled to the main shaft. The second gear intermeshes with the first gear. A suction port is located between the first and second gears and operable when the main shaft is rotated in a reverse direction from the normal pumping direction, during a condition known as backspin.

Abstract: A backspin retarder for a shaft comprises a brake mechanism including a stationary brake member and opposed brake members rotatable with the shaft and movable between braking position in which the movable brake members engage the stationary brake member and a non-braking position in which the movable brake members are removed from the stationary brake member and a brake control mechanism responsive to the direction of rotation of the shaft for disabling the brake mechanism when the shaft rotates in a forward direction and for enabling the brake mechanism when the shaft rotates in a reverse direction.