Basic Principles for Pump Selection

A pump is a general-purpose machine with a wide range of uses. Correct selection of pump type and model is very important. The main purpose is to determine the appropriate pump type, model, parameters, etc. based on the lift, flow rate and changing patterns required by the project. The selection is based on the design parameters determined in the engineering planning and design. The selection of the pump is based on the supporting power machine, transmission and auxiliary equipment and the buildings related to the pump. This is directly related to whether the pump can meet the system design requirements. Pump reliability and service life, pump purchase cost and total life cycle cost. In reality, due to unreasonable selection, many pumps are in abnormal operation, causing energy waste, increased maintenance costs, and even cannot be used normally at all. Therefore, the selection of pumps must be rigorous, and the advantages and disadvantages of different solutions must be repeatedly compared to ensure the normal operation of the pump. The following are the principles and steps for pump selection:

Principles of water pump selection

Basic principles for pump selection:

1. The flow and head (or pressure) requirements during the production process must be fully met according to the needs of production.

2. Select a pump type with good performance and strong adaptability and guarantee to the changes in flow and head required by the project. First, among the established series of products, a Water Pump with high efficiency, good suction performance, and wide range of use should be selected. .When there are multiple pump types to choose from, technical and economic analysis should be carried out and the best ones should be adopted. When a series of products cannot meet the selection requirements, new products can be designed and trial-produced according to prescribed procedures. When the head required by the project changes significantly , it is advisable to choose a pump with a steep drop in the H-Q curve; when the flow rate required by the project changes greatly, a pump with a gentle H-Q curve should be chosen.

3. Try to make the selected pump operate within its high efficiency area, that is, near the design (rated) operating point. The pump unit can operate normally and safely under various operating conditions of the design standards, that is, no cavitation, vibration, overload, etc. will occur. Phenomenon.

4. The selected pump has higher average device efficiency, lower energy consumption and lower operating costs in long-term operation.

5. Select the model and number of pumps to minimize the investment in the entire system (the total investment in equipment costs and civil engineering and installation projects).

6. Easy to construct, easy to operate, manage and maintain.

7. For cascade-operated pumps, the pump model and number should meet the flow coordination requirements between the upper and lower pumps, and try to avoid and reduce insufficient flow or excessive flow of the lower pumps caused by improper flow coordination.

8. For large axial flow pumps and mixed flow pumps, there should be device model test data; when the prototype is significantly changed, the device model test should be re-carried out.

9. When selecting pumps for agricultural drainage and irrigation projects, the requirements of comprehensive water conservancy development should be taken into account as much as possible.

Centrifugal Pumps are preferred.

Centrifugal pumps have the advantages of high speed, small size, light weight, simple structure, pulsation-free infusion, stable performance, and easy operation.

And easy to maintain. Therefore, except for the following circumstances, Centrifugal Pumpsshould be used as much as possible:

(1) When there are measurement requirements, choose a Metering Pump;

(2) When the flow rate is small and the head is high, vortex pumps and reciprocating pumps are used;

(3) When the flow rate is small and the head is high, and the flow (pressure) is required to be pulsation-free, a vortex pump is selected;

(4) When the flow rate is large and the head is low, axial flow pumps and mixed flow pumps are selected;

(5) When the gas content of the medium is 75%, the flow rate is small, and the viscosity is less than 37.4mm2/s, a vortex pump is selected;

(6) When the viscosity of the medium is high (greater than 650~1000mm2/s), rotor pumps and reciprocating pumps (gear pumps and screw pumps) should be used;

(7) For occasions where startup is frequent or pumping is inconvenient, choose a pump with self-priming performance, such as a Self-priming Centrifugal Pump, a self-priming vortex pump, a diaphragm pump, etc.;

(8) When there are special needs, use other pumps, such as Jet Pumps, hose pumps, etc.

(9) Special requirements: Pumps installed in explosion areas or special occasions should use explosion-proof motors or other effective measures according to the level of the explosion area.