【Daily Question: Pump Equipment】Short-answer question, 3/18/2019

Advantages: Easy to load and unload due to horizontal center-opening design. Disadvantages: Difficult to manufacture

The operating characteristics of starting the pump during water washing are high flow rate, complex medium, and easy wear of the volute. This paper addresses the volute erosion problem in a typical quenched split-case pump. By modifying the volute-type discharge chamber and separating its two functions, it effectively solves the issue of rapid wear in the original pump’s discharge chamber. Based on the analysis above, the following conclusions are drawn. (1) The fundamental reason for the erosion of the volute wall and partition tongues by high-volume particle-containing multiphase flow is the high velocity of the fluid exiting the impeller. When the velocity torque is the same, the velocity reaching the volute wall is high; the particles in the medium continuously impact the metal surface, causing the metal surface to detach due to local fatigue, ultimately leading to erosion and damage of the volute. (2) By adding guide vane diffusers in combination with an annular extrusion chamber, the efficiency of converting kinetic energy into pressure energy was improved, the flow pattern within the volute was optimized, the particle velocity at the annular wall surface was reduced, and impact of solid particles on the pump casing was avoided, thereby extending the pump’s service life. (3) An additional advantage of the diffuser is that it improves the efficiency and operational stability of the pump. In summary, the research presented in this paper holds general guiding significance for issues such as pump casing erosion during washing in the industrial sector, as well as erosion of centrifugal pump casings containing a large amount of solid particles, and it possesses significant practical value for engineering applications.

Axially split pumps are all of larger size, or they are used when it is not convenient to remove them axially during maintenance. . Pumps with a radial split design have greater pressure and temperature resistance. API610 stipulates that pumps with a radially split casing must be used in any of the following situations: ① temperatures above 200°C; ② liquids with a relative density of less than 0.7; ③ an outlet gauge pressure of 10 MPa 

Advantages: The pump rotor is easy to disassemble and assemble, making maintenance straightforward. Disadvantages: High precision is required for the machining of the upper and lower mating surfaces; the positioning accuracy of the end flanges is poor

The BB1 series of pumps are axially split, single-stage or two-stage, volute-type, horizontally mounted centrifugal pumps with support at both ends; they can also be designed in a vertical configuration. Suitable for transporting various clean media, or those containing trace particles, that are neutral or corrosive. The BB1 series pumps comply with the American Petroleum Institute API610 10th/API 610 11th design standards. The BB3 pump is an axially split, symmetrically arranged impeller, volute-type, horizontal, multi-stage centrifugal pump with a single-suction or double-suction design for the first stage. It is suitable for transporting various media that are clean or contain trace particles, and that are neutral or corrosive; it exhibits particular stability when handling media containing solid particles. The BB3 series pumps comply with the American Petroleum Institute API610 10th/API 610 11th design standards. The OH-1 horizontal cantilever pump features end inlet and top outlet, a single-stage radial split design, and is a foot-mounted process pump suitable for transporting clean or slightly contaminated, chemically neutral or corrosive media. The BB2 series stage 3 pump is a horizontal, double-supported, radially split, double-volute, three-stage impeller centrifugal pump. This pump type is a centrifugal pump developed specifically for high-flow, high-head operating conditions in various types of equipment. The BB2 series Class 3 pumps comply with the American Petroleum Institute API 610 10th/API 610 11th design standards. Class 3 pumps go beyond the definition of the BB2 pump type as specified in API610, but they fully meet the design and manufacturing requirements of API610.

This post was last edited by Frozen Desert on 2019-3-18 at 13:30. Pumps that are not suitable for radial splitting can be used with axial splitting; positioning may be inaccurate, but positioning pins are usually available. However, when lowering it, be careful to maintain the verticality of the lifting point to avoid touching other parts

Advantages: 1. The horizontally split pump rotor is easy to disassemble and assemble, making maintenance simpler； 2. With a separate housing design, it is easy to cast the flow channels; complex channel shapes can be designed, resulting in fewer casting defects. Disadvantages: 1. High precision is required for planar processing at the upper and lower sections, making the processing difficult ； 2. It is difficult to achieve static sealing at the balanced sealing surface when combining upper and lower elements ； 3. The positioning accuracy of the end shoulders is slightly poor ； 4. The weight of the hydraulic components in the housing is high. 5. It cannot be used in high-temperature environments where the specific gravity is less than 0.7

Advantages: 1. The horizontally split pump rotor is easy to disassemble and assemble, making maintenance simpler； 2. With a separate housing design, it is easy to cast the flow channels; complex channel shapes can be designed, resulting in fewer casting defects. Disadvantages: 1. High precision is required for planar processing at the upper and lower sections, making the processing difficult ； 2. It is difficult to achieve static sealing at the balanced sealing surface when combining upper and lower elements ； 3. The positioning accuracy of the end shoulders is slightly poor ； 4. The weight of the hydraulic components in the housing is high. 5. It cannot be used in high-temperature environments where the specific gravity is less than 0.7

Axial split structure: Advantages: Generally used in large pumps, easy for maintenance. Disadvantage: Many leakage points in the dynamic seal ； Due to axial forces and sealing structure limitations, it is mostly used in applications with low temperatures and low head. Radial split structure: Advantages: Resistant to axial forces and provides reliable sealing; suitable for transporting fluids at high temperatures and over high head heights ； Dynamic seals have few leakage points. Disadvantages: It has a complex structure and low reliability when used in large pumps, and is generally used in small pumps.

Both BB3 and BB5 are code names for multi-stage centrifugal pumps, but their pump casings and the way they are divided differ. BB3 is an axially split multi-stage pump, while BB5 is a radially split double-casing multi-stage pump. https://attach01.hcbbs.com/forum/201309/05/100049d75m5mzti5nt7edm.gif According to API610, a radially split pump casing should be used in any of the following operating conditions. 1. The temperature of the liquid being pumped is greater than 200 degrees ； 2. Flammable or toxic media with a relative density of less than 0.7 at the pumping temperature ； 3. When pumping flammable or toxic liquids at an outlet pressure higher than 10 MPa. For applications whose operating conditions fall outside the above range, an axially split pump can be used, which facilitates maintenance. However, from the perspective of operational reliability, axial split pumps are not recommended.