Understanding the five major characteristics of water pumps can make a good selection
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 criteria for water pumps should be based on the process flow, water supply and drainage requirements, and considered from five aspects: liquid delivery 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. If the design institute can calculate the normal, minimum, and maximum flow rates of the pump in the process design. When selecting a pump, the maximum flow rate should be taken as the basis, taking 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 head required for the device system is another important performance data for selecting pumps, and generally the head should be selected by enlarging the margin by 5% -10%.
3. The properties of liquids include the name of the liquid medium, physical properties, chemical properties, and other properties. Physical properties include temperature, density, viscosity, solid particle diameter, and gas content in the medium. This involves the system's head, effective cavitation allowance calculation, and the appropriate type of pump. Chemical properties mainly refer to the chemical corrosiveness and toxicity of the liquid medium, which are important criteria for selecting pump materials and choosing the type of shaft seal.
4. The pipeline layout conditions of the device system refer to the height, distance, and direction of the liquid delivery, as well as data such as the lowest liquid level on the suction side and the highest liquid level on the discharge side, as well as pipeline specifications and their lengths, materials, pipe specifications, quantities, etc., in order to calculate the comb head and verify the cavitation allowance.
5. There are many operating conditions, such as the operation of liquid T, saturation vapor force P, suction side pressure PS (absolute), discharge side container pressure PZ, altitude, environmental temperature, whether the operation is intermittent or continuous, and whether the pump position is fixed or movable.
