1. What is the difference in structure between BB1 and BB2?
BB1: axially split double-suction pump
BB1 is an axially split, double-end supported single-stage or two-stage pump, often using a double-suction impeller. The medium enters from both sides of the impeller at the same time, which can reduce the inlet flow rate and the risk of cavitation, and balance most of the axial forces.
The pump casing is divided into upper and lower parts along the center line of the shaft. During maintenance, the impeller, shaft, seal and wear ring can be inspected by opening the upper pump casing. Generally, there is no need to disassemble the inlet and outlet pipes. Its main advantages are large flow, stable operation and convenient maintenance.
BB2: radially split process pump
BB2 is a radially split, two-end supported single-stage or two-stage pump. The pump casing usually adopts a centerline support structure. Compared with the axially split BB1, the BB2 pump casing has a tighter pressure-bearing boundary and can better maintain the center position of the pump shaft and the pipe when the temperature changes.
BB2 is usually used with heavy-duty bearing systems, mechanical seals and API seal flushing solutions, and is suitable for high temperature, high pressure, flammable, explosive or toxic media.
2. Comparison of main parameters and performance of BB1 and BB2
| Comparison project | API 610 BB1 | API 610 BB2 |
|---|---|---|
| Pump casing form | Axis split | Radial split |
| Common impellers | Double-suction impellers | Single-suction or double-suction impellers |
| Main performance characteristics | Large flow, medium and low lift< /td> | Medium-high flow rate, medium-high lift |
| Cavitation performance | Double-suction structure usually has more advantages | According to the inlet conditions and hydraulic model Fixed |
| Temperature adaptability | Mainly used for normal and medium temperature conditions | More suitable for high temperature and thermal cycle conditions |
| Pressure bearing capacity | Suitable for large flow and medium pressure | More suitable for higher system pressure |
| Inspection method | Open the upper pump casing for inspection< /td> | Disassemble the radial pump cover or pump body for inspection |
| Typical media | Water, crude oil, refined oil and circulating fluid | Hydrocarbons, hot oil, chemical liquids Body |
| Typical applications | Oil pipelines, circulating water, water intake projects | Oil refining, petrochemical and high temperature process equipment |
Feiyue Pump Industry's BB1 horizontal double-suction pump product can have a flow rate of approximately 20,000m³/h, a head of approximately 320m, a design pressure of up to 15MPa, and an operating temperature of approximately 205°C. Actual parameters should be confirmed based on pump specifications, media properties, materials and speed.
3. Which working conditions are more suitable for BB1?
When the project has the following characteristics, priority should be given to BB1 evaluation:
The system needs to transport a large flow, but the head is relatively limited;
The NPSH that the device can provide is small;
Media It is crude oil, refined oil, industrial water or liquids with relatively stable properties;
Users value the convenience of on-site disassembly, assembly and maintenance;
The pump needs to operate stably for a long time and reduce the impact of axial force on the bearing life.
BB1 is commonly used in long-distance oil pipelines, storage and transportation systems, refinery circulating water, power plant circulating water, urban water supply and large-scale water intake projects. For projects with "large flow rate + limited inlet conditions", the double-suction structure is usually more suitable than the ordinary single-suction process pump.
4. Under which working conditions should BB2 be preferred?
BB2 is more suitable for the following working conditions:
The medium temperature is high, and the pump body has significant thermal expansion;
The system inlet pressure or outlet pressure is high;
Transporting flammable, explosive, toxic or high-value media;
The equipment undergoes frequent start-stop cycles as well as heating and cooling processes；
The device has frequent starts and stops, heating or cooling processes;
It has higher requirements on mechanical seals, bearing systems and API auxiliary pipelines;
Pumps are used in oil refining, hydrogenation, aromatics, coal chemical industry or high-temperature heat transfer oil processes.
The BB2 centerline support structure can reduce the impact of thermal expansion of the pump casing on coupling alignment, and the radially split pump casing is also more suitable for withstanding high temperatures and high pressures. Therefore, in key petrochemical processes, even if BB1 can cover the flow rate and head, it does not mean that its reliability will definitely meet the working condition requirements.
5. Frequently Asked Questions from Buyers
Is BB2 definitely more reliable than BB1?
Not necessarily. Reliability depends on matching working conditions. BB2 is more suitable for high-temperature and high-pressure processes, but for large-flow circulating water or oil transportation conditions, BB1 has a more direct structure, and may have better efficiency and maintenance convenience.
Can BB1 transport high-temperature oil products?
Yes, but you need to check the design temperature, pump support method, materials, sealing and thermal expansion. If temperatures are high, pressure is high, and thermal cycling is frequent, BB2 should generally be evaluated first.
6. Feiyue Pump Industry BB1 and BB2 product solutions
For projects with large flow, low inlet margin and emphasis on maintenance convenience, BB1 can be preferred; for high temperature, high pressure, hazardous media and critical continuous processes, BB2 should be selected. Engineers will check performance curves, NPSH, materials, mechanical seals, bearing configurations and test requirements based on complete working conditions to avoid selection based solely on flow, head or price.
