GDS (OH3)

The API OH3(model GDS) pump is a vertical in-line, single-stage, single-suction centrifugal pump designed for heavy-duty process services in the petroleum, petrochemical, and chemical industries. Its most distinguishing characteristic is the vertical in-line configuration: the suction and discharge nozzles are arranged on the same horizontal axis, allowing the pump to be mounted directly into the piping system without a baseplate. This eliminates the need for foundation works and significantly reduces floor space requirements, making it particularly suitable for offshore platforms, refineries, and other installations where space is at a premium.

The pump conforms to the latest edition of API 610 (ISO 13709) and is classified as OH3 type. The casing is radially split with a volute design, and larger sizes may employ a double-volute configuration to minimize radial loads. A separate bearing housing is provided to absorb all pump thrusts, distinguishing OH3 from close-coupled designs. The shaft is rigidly designed with the first lateral critical speed well above the operating speed, ensuring minimal deflection and vibration. The impeller is a closed, radial-flow design, dynamically balanced and fitted with replaceable wear rings on both sides. For fluids sensitive to clogging, semi-open and open impellers are available as an option.

Typical capacities range from small flows up to approximately 1,000 m³/h, with some specialized designs reaching higher. Heads typically reach up to 300 m, with design pressures up to 50 bar. Operating temperatures span from −40°C to +250°C depending on pump size and construction, covering applications from cryogenic services to high-temperature refinery processes. The seal chamber complies with API 682 and can accommodate single, dual, or engineered mechanical seals with appropriate flush plans.