API RP 11G-2013 pdf download.Recommended Practice for Installation, Maintenance, and Lubrication of Pumping Units.
2 Normative References The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. API Specification 11E-2013, Specification for Pumping Units 3 Terms and Definitions For the purposes of this document, the following definitions apply. 3.1 base The basic frame or skid to which a pumping unit is assembled. Typically is the structural element that interfaces with or is clamped to the foundation. 3.2 brake Component of a pumping unit that is often composed of a disk or drum mounted on the reducer input shaft combined with a mechanism to impart a restraining friction torque and restrain the motion of all rotary joints. 3.3 carrier bar Part of the pumping unit that supports the load of the sucker rod string through the polished rod clamp. 3.4 center bearing Structural bearing assembly supporting the walking beam of a class 1 lever design pumping unit. 3.5 certified installation print Drawing reviewed and approved (stamped) by a licensed professional engineer competent in the areas of site preparation, foundations, and proper mounting requirements of heavy industrial equipment. 3.6 cranks Driving link in the four-bar linkage of a beam pumping unit that is located between the output shaft of the gear reducer and the pitman link.
3.7 cross-beam clamp Device used to constrain the pumping unit to its supporting foundation. Often a beam-like member placed on top and spanning the base rails with anchor bolts joining it to the foundation anchorage. 3.8 equalizer Connects the pitman links to the rear of the walking beam. 3.9 foundation Structural element designed to support the pumping unit base and transmit loads into the earth via distributed contact with soil or piles. 3.10 horsehead Component of a beam pumping unit designed to transmit force and motion from the walking beam to the flexible wireline. 3.11 pitman Connecting link in the pumping unit mechanism between the cranks and the equalizer. 3.12 prime mover Primary driving mechanism imparting rotary motion on the pumping unit system. Typically connected to the speed reducer via a belt drive. Common variants are electric motors and internal combustion engines. 3.13 pumping unit Machine for translating rotary motion from a crankshaft to linear reciprocating motion for the purpose of transferring mechanical power to a downhole pump. 3.14 rod clamp Clamping device that is affixed to the polished rod of the well for the purpose of either transmitting axial loads to other components such as the carrier bar or constraining motion. 3.15 samson post Support member of the walking beam that has a bearing mounted to a fixed location atop which is attached to and provides the fulcrum location for the walking beam. 3.16 sheave Rotating component of a V-belt drive designed to transmit power from the belts to the rotating shaft on which it is affixed or vice versa. 3.17 skidding Horizontal movement as a result of dynamic forces from rotating cranks, counterweights, and other bodies.
4 Foundation and Site Preparation 4.1 General The following discusses the typical role and requirements associated with the pumping unit foundation. It describes a general process of preparing a location to support a pumping unit installation. Pumping units, by their nature, transmit very large forces to the supporting earth. Foundations provide a means of distributing these forces over a broad area allowing the soil and underlayment to generate sufficient strength and stiffness to withstand them while yielding only very small deflections. The stability and rigidity provided by the foundation and the site preparations necessary to constrain movement are essential in maintaining proper alignment and providing the pumping unit with long operational life. Many times, structural failures involving pumping units can be traced back to an insufficient foundation or poor site preparation practices. The means by which pumping unit foundations transmit their loads into the earth take several forms ranging from simple surface contact with the underlying soil to driven or helical piles sunk deeply into the earth. In each case, the foundation must possess sufficient strength and stiffness to allow localized forces applied by the pumping unit to be adequately distributed over an area of soil contact or to a series of piers (piles) so that the local load bearing capacities of these elements are not exceeded. It is also often necessary for the foundation to possess sufficient mass to constrain dynamic up-lifting forces produced by some pumping unit models and prevent degradation of the soil contact interface under the foundation. The mass of the foundation also helps to stabilize the unit against skidding.