Choosing the right API 610 pump is critical for reliable operation in petroleum, petrochemical, and natural gas applications. Among the most common horizontal configurations, OH and BB pumps cover different flow, head, temperature, pressure, and maintenance requirements.
This guide explains how to select between API 610 OH1, OH2, BB1, BB2, BB3 and BB4 pump.
1. API 610 OH Pumps: When Are They Suitable?
OH pumps are single-stage overhung centrifugal pumps. The impeller is supported on one side of the bearing assembly.
API 610 OH1 Pump
An API 610 OH1 pump is a foot-mounted, single-stage overhung pump. Its relatively simple construction makes it suitable for less demanding process services where the required flow and head can be achieved with a single-stage design.
OH1 can be considered when compact construction, straightforward installation, and economical operation are important.
API 610 OH2 Pump
An API 610 OH2 pump is a centerline-mounted, single-stage overhung pump with a separate bearing housing. The bearing housing absorbs the forces acting on the shaft and helps maintain rotor position during operation.
Compared with OH1, OH2 is generally preferred for more demanding process applications, particularly where thermal stability and continuous operation are important.
2. API 610 BB Pumps: When Are They Better?
BB pumps are between-bearings pumps, meaning the rotor is supported by bearings on both sides. This configuration provides strong rotor support and is widely used for higher-flow, higher-head, or more demanding process services.
API 610 BB1 Pump
An API 610 BB1 pump is an axially split, one- or two-stage, between-bearings pump. The casing can be opened axially, which provides convenient access to internal components during maintenance.
BB1 is commonly considered for high-flow applications where easy maintenance and a robust between-bearings structure are important.
API 610 BB2 Pump
An API 610 BB2 pump is a radially split, one- or two-stage, between-bearings pump.
Its radial split construction provides a robust pressure-containing design and can be suitable for services requiring higher pressure and temperature capability than typical single-stage configurations.
API 610 BB3 Pump
An API 610 BB3 pump is an axially split, multistage, between-bearings pump.
With multiple impellers, BB3 is suitable for applications requiring high head while maintaining a balanced and stable rotor arrangement. Typical applications include boiler feedwater, pipeline boosting, high-pressure water injection, and other high-head process services.
API 610 BB4 Pump
An API 610 BB4 pump is a single-casing, radially split, multistage, between-bearings pump. It is also known as a ring-section, segmental-ring, or tie-rod pump.
Its segmented construction provides a compact solution for multistage, high-head applications. However, the interfaces between individual sections can create potential leakage paths, so the actual application and project requirements should be carefully evaluated.
3. OH vs. BB: How Should You Decide?
The basic selection logic can be summarized as follows:
|
Pump Type |
Basic Design |
Typical Selection Consideration |
|
OH1 |
Foot-mounted, single-stage |
Simpler process applications |
|
OH2 |
Centerline-mounted, single-stage |
More demanding process service |
|
BB1 |
Axially split, 1–2 stage |
High flow and easy maintenance |
|
BB2 |
Radially split, 1–2 stage |
Higher-pressure/temperature service |
|
BB3 |
Axially split, multistage |
High-head applications |
|
BB4 |
Radially split, multistage |
Compact high-head applications |
These are general guidelines rather than strict selection rules. Actual pump selection should be based on the required flow rate, head, operating temperature, pressure, fluid properties, NPSH, materials, operating hours, and maintenance requirements.
4. Why Is Professional API 610 Pump Selection Important?
Selecting an API 610 pump is not simply a matter of matching flow and head. Pump structure must also withstand the actual mechanical and thermal loads throughout the operating range.
An experienced API 610 pump manufacturer can evaluate the process conditions and recommend the appropriate OH or BB configuration, materials, sealing system, bearing arrangement, and auxiliary systems.
Conclusion
For a simple rule of thumb:
OH1/OH2 → single-stage, overhung pumps
BB1/BB2 → one- or two-stage, between-bearings pumps
BB3/BB4 → multistage, between-bearings pumps
The right API 610 pump should always be selected according to the complete operating conditions rather than pump type alone. Proper selection improves reliability, maintenance performance, and long-term operating efficiency in demanding process applications.