1, the flow rate is one of the important performance of the election pump data, which is directly related to the entire plant's production capacity and delivery capacity. Such as the design process can be calculated in the pump normal, minimum, maximum three kinds of flow. Select the pump to the maximum flow as the basis, taking into account the normal flow, in the absence of maximum flow, it is usually desirable 1.1 to 1.2 times the normal flow as the maximum flow. 2, the lift system required for installation of the pump is another important performance data, generally to enlarge the 5% -10% head lift to choose. 3, the nature of the liquid, including the name of the liquid medium. Physical, chemical and other properties. Physical properties of temperature, density, viscosity, solid particles in the medium diameter and gas content. This relates to the system lift, the effective cavitation allowance calculation and the type of suitable pump: chemical, mainly refers to the chemical corrosivity of liquid medium (common chemical pump selection principle) and toxicity, is the choice of pump material and use that kind of shaft Seal type important basis. On the transport of flammable, explosive toxic or valuable medium pump, shaft seal reliable or require leak-free pump; for flammable liquids should also be used explosion-proof motor as a power plant. 4, the mechanical reliability, low noise, small vibration; 4, the economic should take into account the equipment cost, operating costs, maintenance costs and management costs of the lowest total cost; 5, centrifugal pump with high speed, small size, weight Light, high efficiency, large flow, simple structure, infusion without pulsation, stable performance, easy operation and maintenance and other features; In general, 6, in addition to the measurement requirements, the flow is small and no suitable small flow high lift centrifugal pump, Very low head flow, medium viscosity, medium gas content of 75%, on the occasion of frequent or inconvenient filling irrigation and other special requirements, should be used whenever possible centrifugal pump. Because the centrifugal pump with high speed, small size, light weight, high efficiency, large flow, simple structure, infusion without pulsation, stable performance, easy operation and maintenance convenience and so on. 7, many operating conditions, such as the operation of the liquid T saturated steam P, suction side pressure PS (absolute), the discharge side of the tank pressure PZ, altitude, ambient temperature operation is gap or continuous, the pump position is fixed Or removable.
