FAP(OH1)

The API OH1(FAP) pump is a horizontally mounted, foot-supported, single-stage overhung centrifugal pump designed to API 610 / ISO 13709 standards. Its defining feature is the end-suction, top-discharge configuration with a radially split casing, where the impeller is cantilevered at the end of the shaft outside the bearing housing. The pump casing is supported by feet bolted directly to a baseplate, making it the most basic and widely used overhung design. The back pull-out construction allows the complete rotor assembly—including the impeller, shaft, bearings, and seal—to be removed without disconnecting the suction and discharge piping or disturbing the driver, significantly simplifying maintenance.

These pumps are engineered for general refinery and petrochemical services where moderate pressures and temperatures are involved. Common applications include utility water transfer, boiler feed boosting, light hydrocarbon handling, caustic and amine circulation, and general process charge duties. The OH1 design is particularly suited for continuous, stable operation in non-critical services, with standard temperature ranges from -40°C to 200°C and design pressures typically up to 20 bar.

Technically, the OH1 pump features a heavy-duty shaft with minimal overhang to control deflection at the seal chamber, extending mechanical seal and wear ring life. Axial thrust is typically balanced through balance holes and wear rings on the impeller. Bearings commonly consist of a radial ball bearing and a back-to-back paired angular contact thrust bearing, oil-lubricated with oil rings and cooling fins for thermal management. The pump is fully compliant with API 682 seal chambers and accepts a variety of cartridge mechanical seals and piping plans. Available in materials ranging from carbon steel to stainless steel and duplex alloys, the OH1 achieves flow capacities up to 2,600 m³/h and heads up to 300 meters, making it the standard workhorse for general industrial pumping duties.