How To Choose A Water Pump

Apr 09, 2026

Ensure the normal and economical operation of the pump system, that is, the selected pump can not only meet the requirements of the flow rate and head of the pipeline system, but also ensure the stable operation of the pump within the section, while not having a reasonable structure.

 

1, How to choose a water pump:

 

(1) The pump should meet the maximum flow and head or flow requirements required for production, and make its normal operating point as close as possible to the design point of the pump. So as to ensure the long-term operation of the pump in the area and improve the economic efficiency of the equipment's long-term operation.

(2) Strive to choose pumps with simple structure, small volume, light weight, and high speed

(3) The selected pump should ensure safe, reliable, and stable operation. Therefore, the selected pump should not have a hump shaped performance curve; If choosing a pump with a hump shaped performance curve. The operating point should be placed to the right of the peak point, and the head or pressure should be lower than the head or pressure at zero flow to facilitate parallel operation without backup. If there is a large change in flow rate and a small change in head or pressure during use, a steep drop performance curve should be selected; If a large change in head or pressure and a small change in flow rate are required, a steep drop performance curve should be selected. For water pumps, good anti cavitation performance should also be considered.

 

 

(4) For pumps with special requirements, efforts should be made to meet their special requirements as much as possible. For special installation locations, consideration should be given to small volume and easy installation of inlet and outlet pipelines.

(5) Must meet the requirements of medium characteristics.

For pumps that transport flammable, explosive, toxic, or valuable media, reliable shaft seals or leak free pumps are required, such as magnetic drive pumps, pneumatic diaphragm pumps, and shielded pumps.

For pumps transporting corrosive media, it is required to use corrosion-resistant materials for the overcurrent components, such as stainless steel centrifugal pumps and engineering plastic magnetic drive pumps.

For pumps transporting media containing solid particles, it is required to use wear-resistant materials for the overcurrent components, and if necessary, the shaft seal should be flushed with clean liquid.
(6) High mechanical reliability, low noise, and minimal vibration.
(7) Economically, it is necessary to comprehensively consider the total cost of equipment, operation, maintenance, and management fees to minimize them.

 

(8) Centrifugal pumps have the characteristics of high speed, small size, light weight, high efficiency, simple structure, no pulsation in infusion, stable performance, easy operation and maintenance.
Due to the ever-changing uses and conditions of pumps, as well as the wide variety of pump types, it is essential to choose pumps correctly to meet various engineering requirements. When choosing a pump, the first step is to determine which type of pump to choose based on production requirements, the type and quality of the fluid being transported, and the type and purpose of the pump. For example, when transporting general clean water, a centrifugal pump should be selected. When transporting sewage, a sewage pump should be selected, and when transporting mud, a mud pump model should be selected, etc.

2, The program for selecting water pumps and the precautions for selecting water pumps are summarized as follows:

(1) Fully understand the original data such as the purpose of the pump, pipeline layout, terrain conditions, transported fluid conditions, water level, and transportation conditions.
(2) Reasonably determine the maximum flow rate and maximum head according to engineering requirements. Then add a safety margin of 10% to 20% for unforeseeable factors such as calculation errors and leakage as the basis for selecting pumps.
(3) Select the appropriate equipment type based on known conditions. The product samples provided by the manufacturer usually include the applicable range of this type of pump. We should try to choose products that are serialized, standardized, universal, and have excellent performance.
(4) After determining the pump type, the specific equipment model should be selected based on the known flow rate, head, or pressure head, and the working point should be located in the efficiency zone.
(5) It should be considered whether to adopt parallel or series working mode based on specific circumstances. Should there be backup equipment.
(6) When determining the pump model, it is also necessary to determine its speed, prime mover model, power, transmission mode, pulley size, etc. If the performance parameter table includes the motor model and the rigid component model, they can be directly applied. If the performance curve chart is used for selection, only the shaft power curve is shown on the chart, and the motor model and transmission accessories need to be selected separately. The direction of pump inlet and outlet should be coordinated with the pipeline system. For pumps, it is also necessary to determine the allowable suction vacuum height or necessary cavitation allowance, and calculate whether the installation height meets the requirements.

 

(7) It should be noted that the data provided in the product sample was obtained under specified conditions. The data is usually obtained from experiments conducted at an air temperature of 20 ° C.
(8) Determine the number and standby rate of pumps. For a normally operating pump, only one is generally used because a large pump is equivalent to two small pumps working in parallel (referring to the same head and flow rate). The efficiency of a large pump is higher than that of a small pump. Therefore, from an energy-saving perspective, it is better to choose a large pump instead of two small pumps. However, in the following situations, parallel cooperation of two pumps can be considered.
The flow rate is very high. One pump cannot reach this flow rate.
For large pumps that require a 50% backup rate, two smaller pumps can be used instead. One backup pump (out of a total of three)
For some large pumps, pumps with a flow rate requirement of 70% can be operated in parallel without the need for a backup pump. When one pump is under maintenance, the other pump can still handle 70% of the production delivery.
For pumps that require 24-hour continuous operation, there should be a backup pump.