Rod Lift Surface Pumping Units

Class I lever-system units with the speed reducer and crank positioned at the rear and the saddle bearing fulcrum near the center of the walking beam. They are the most common and lowest-cost configuration, well suited to a broad range of medium-depth wells.

Class III units that use a compressed-air cylinder rather than steel counterweights to balance the rod-string load. They are lighter and more compact for a given capacity, making them favorable for offshore platforms and heavy, deep-well loads.

Class III geometry units with the gearbox shifted toward the wellhead and an offset crank that lowers peak torque and rod stress over the pumping cycle. They improve gearbox efficiency on deeper or higher-load wells compared with conventional geometry.

Units that deliver polished-rod strokes substantially longer than conventional beam units, using rolling-flexible-belt, hydraulic, or chain-drive mechanisms. The longer, slower stroke reduces cycles per barrel and rod fatigue, benefiting high-volume and deep wells.

Smaller-capacity units in which counterweights are mounted directly on the walking beam rather than on the cranks. They are used on shallow, low-load wells where a simple, economical balancing arrangement is adequate.

Units in which counterweights are mounted on the rotating cranks to offset the rod-string load. Crank balancing provides effective counterbalance over a wide load range and is standard on medium- and higher-capacity beam units.

Double- or triple-reduction enclosed gear reducers that step the prime-mover speed down to the slow crank rotation required for pumping. Gearboxes are rated by peak torque (in inch-pounds) and are a primary sizing parameter under API Spec 11E.

Power-transmission and replacement parts including V-belts and sheaves, brakes, bearings, wrist pins, polished-rod clamps, wireline bridles, and counterweights. These items support routine maintenance and rebalancing of installed units.