Understanding the five characteristics of water pumps can provide a good selection method

A water pump is a mechanical device that transports or pressurizes liquids. It transmits the mechanical energy or other external energy of the prime mover to the liquid to increase the energy of the liquid. It is mainly used to transport liquids, including water, oil, acid-base liquid, emulsion, suspended lotion and liquid metal. It can also transport liquids, gas mixtures and liquids containing suspended solids. The selection of water pumps should be based on the process flow, water supply and drainage requirements, and be considered from five aspects, including liquid conveying capacity, device head, liquid properties, pipeline layout, and operating conditions.
1. Flow rate is one of the important performance data for selecting water pumps, which directly affects the production and transportation capacity of the entire device. In the process design of the design institute, the normal, minimum, and maximum flow rates of the pump can be calculated. When selecting a pump, it is based on the maximum flow rate and takes into account the normal flow rate. When there is no maximum flow rate, 1.1 times the normal flow rate is usually taken as the maximum flow rate.
2. The required head of the device system is another important performance data for pump selection, and the head is generally selected by amplifying the margin by 5% -10%.
3. Liquid properties, including the name of the liquid medium, physical properties, chemical properties, and other properties, include temperature c, density d, viscosity u, solid particle diameter in the medium, and gas content, etc. This involves the system's head, effective cavitation margin calculation, and the appropriate pump type: chemical properties, mainly referring to the chemical corrosiveness and toxicity of the liquid medium, are important criteria for selecting pump materials and the type of shaft seal.
4. The pipeline layout conditions of the device system refer to the liquid delivery height, distance from the liquid delivery direction, the lowest liquid level on the suction side, the highest liquid level on the discharge side, and other data, as well as pipeline specifications and their lengths, materials, pipe fittings specifications, quantities, etc., in order to calculate the system head and verify the cavitation margin.
5. There are many contents of operating conditions, such as liquid operation T saturated vapor force P, suction side pressure PS (absolute), discharge side container pressure PZ, altitude, whether the ambient temperature operation is intermittent or continuous, and whether the pump position is fixed or movable.