1. Flow rate is one of the important performance data of pump selection. Based on the maximum flow rate, taking into account the normal flow rate, when there is no maximum flow rate, 1.1 times of the normal flow rate can usually be taken as the maximum flow rate. Generally, the head should be selected after amplifying 5% and 10% margin.
2. The head required by the device system is another important performance data of the pump. Including the name of the liquid medium, the nature of the liquid. Physical properties, chemical properties and other properties, physical properties include temperature, density, viscosity, diameter of solid particles in the medium and gas content, etc., which involve the head of the system, the calculation of effective cavitation allowance and the type of suitable pump: chemical properties, mainly refers to the chemical corrosiveness and toxicity of the liquid medium, the important basis for selecting pump data and selecting which shaft seal type.
3. The pipeline layout conditions of the device system refer to the liquid feeding height, liquid feeding distance, and liquid delivery direction. Some data such as the highest liquid level on the discharge side and pipe specifications and their lengths, data, pipe fitting specifications, quantities, etc., in order to calculate the comb head and check the NPSH.