In the classification system of centrifugal pumps, both Type Between Bearing 3 and Type Between Bearing 4 belong to axially split, multi-stage segmental centrifugal pumps. Although they are both commonly used fluid transfer equipment in the industrial field, there are significant differences in their structural design, performance characteristics, and application scenarios. Clarifying these differences is of great significance for equipment selection, operation and maintenance, and the improvement of industrial production efficiency.
Centrifugal Pump Type Between - Bearing Axially Split Multistage Centrifugal Pump adopts a separated design of rotor and casing. Its rotor assembly can be pulled out as a whole from one end of the pump body, without disassembling the inlet and outlet pipelines or the connection structure between the pump body and the base. When conducting maintenance on internal components, it has less impact on the surrounding pipeline system. In contrast, Centrifugal Pump Type BB4 has an integral casing structure. To take out the rotor assembly, it is necessary to first disassemble the inlet and outlet pipelines of the pump body and part of the casing structure, resulting in a relatively complex overall disassembly and assembly process.
The bearings of Centrifugal Pump Type Between - Bearing Axially Split Multistage Centrifugal Pump are arranged in a double-end support manner, with bearings installed at both ends of the rotor respectively. This arrangement can more evenly bear the radial and axial forces generated during the operation of the rotor. Under long-term high-load operation, the rotor has higher stability and relatively smaller vibration amplitude. The bearings of Centrifugal Pump Type BB4, however, are designed with single-end concentrated support, where bearings are centrally installed at one end of the rotor. Although it has strong ability to bear radial forces, it relies on other auxiliary structures to cope with axial forces, and its overall load resistance is slightly weaker than that of Type BB3.
Centrifugal Pump Type BB3 is equipped with a double mechanical seal system. The seal assembly includes two sets of sealing faces, which block fluid leakage through the double sealing effect. At the same time, an isolation fluid can be introduced into the seal cavity, which not only cools the seal assembly but also further improves the sealing effect. It is suitable for transferring volatile, toxic, or corrosive fluid media. Centrifugal Pump Type BB4 mostly adopts a single mechanical seal structure, which achieves sealing through only one set of sealing faces. It has a relatively simple structure and low maintenance cost, making it more suitable for transferring non-corrosive and non-volatile ordinary fluid media.
Due to the large number of components in the double mechanical seal structure of Centrifugal Pump Type BB3, more parts need to be disassembled during seal maintenance, which requires high professional operation skills from maintenance personnel and results in a relatively long maintenance cycle. The single mechanical seal structure of Centrifugal Pump Type Single - Casing Radially Split Multistage Between - Bearings Centrifugal Pump is simple. During maintenance, only a small number of core seal parts need to be replaced, with a simple operation process, higher maintenance efficiency, and lower daily operation and maintenance costs.
Based on its stable structural design and efficient sealing system, Centrifugal Pump Type BB3 is more suitable for industries such as petrochemical and fine chemical industries. It is used to transfer high-viscosity, corrosive, or fluid media containing a small amount of impurities. Especially in production processes that require long-term continuous operation and have extremely high requirements for equipment reliability and sealing performance, it can exert better performance.
With its simple structure and low maintenance cost, Centrifugal Pump Type BB4 is widely used in scenarios such as municipal water supply, agricultural irrigation, and ordinary industrial circulating water transfer. It is mainly used to transfer clean, non-corrosive, and low-viscosity fluid media. In scenarios where the requirements for equipment performance are relatively moderate and emphasis is placed on the convenience of operation and maintenance and cost control, it has high cost-effectiveness.
In summary, the differences between Centrifugal Pump Type BB3 and Type BB4 mainly lie in the complexity of structural design, the reliability of sealing systems, and the specificity of application scenarios. Enterprises need to comprehensively consider the characteristics of their own transferred media, production working condition requirements, and operation and maintenance cost budgets when selecting models. As a professional enterprise focusing on the R&D and production of centrifugal pumps, TEFFIKO has a deep understanding of the technical characteristics and industry needs of these two pump types. The Centrifugal Pump Type BB3 provided by TEFFIKO strictly follows the standards of high sealing and high stability, which can meet the fluid transfer needs of harsh industries such as chemical industry. At the same time, TEFFIKO has also optimized the structural design of Centrifugal Pump Type BB4 for ordinary fluid transfer scenarios, reducing the difficulty and cost of operation and maintenance while ensuring basic performance, so as to provide customers in different industries with more adaptable fluid transfer solutions.
