Abstract: In the pump of choice, to take into account the characteristics of different pumps. The classification of the pump according to the principle of the pump acting on the liquid is divided into two major categories of vane and volumetric, vane pump is the centrifugal force generated by the blades in the rotation of the pump inhales or discharges the liquid. Positive displacement pump is the pump piston or rotor in the reciprocating or rotational movement of the squeezing effect of liquid into or out. Vane pump blade structure is divided into different pump centrifugal pump, axial pump, vortex pump. Positive displacement pump is divided into piston (plunger) pump, rotor pump. 4.1.1 Centrifugal pump liquid temperature under the conveying temperature is not greater than 650mm2 / S, or pump efficiency decreased significantly. (When the viscosity is more than 650mm2 / S, the centrifugal pump performance decline greatly, generally do not choose centrifugal pump, but because of centrifugal pump infusion without pulsation, no safety valve and flow adjustment is simple, so we often see in the chemical production of centrifugal Pumps are used to deliver liquids with viscosities up to 1000 mm2 / s). The flow is relatively large, while the head is relatively low teach liquid dissolved or entrained in the liquid is not more than 5% (volume) of liquid containing solid particles, should choose a special centrifugal pump (such as mud pump) requires large flow changes, head changes small Selection of flat flow - Centrifugal lift head curve, requiring small changes in flow, head changes, should choose the steep drop of flow - Centrifugal pump head curve. 4.1.2 Positive displacement pump Fluid viscosity greater than 650mm2 / S, smaller flow and relatively high lift, should choose reciprocating pump. Liquid dissolved or entrained gas allows slightly more than 5% (volume) of liquid Need accurate measurement, the choice of plunger metering pump, liquid strict leak-free, optional diaphragm metering pump Poor lubrication performance of the liquid should not be used gear Pump and three screw pump, optional reciprocating pump. Small flow, the temperature is low, the pressure requirements of stability, should use a rotor pump or twin screw pump. 4.2 According to the device required flow and lift, according to the classification of the pump and the scope of the initial determination of the pump selection, due to the simple structure of the centrifugal pump, infusion without pulsation, flow adjustment is simple, so in addition to centrifugal pump is difficult to do the occasion, as far as possible selection Centrifugal pump. After the selection of the pump is confirmed, it is possible to select the pump series and materials according to the process plant parameters and the medium characteristics. Then according to the pump factory to provide samples and technical information to determine the specific pump model (specifications). 4.3 for special media pump delivery gas-containing liquid, the pump flow, lift, the efficiency has declined. The greater the gas content, the more rapid decline in efficiency. With the gas content increases, the pump appears additional noise, vibration, severe corrosion or increase when there is no flow, broken axis phenomenon. In order to ensure the reliable operation of the pump, measures can be taken to reduce the gas content in the liquid: Type Applicable viscosity range mm2 / s Vane pump Centrifugal pump <150 Vortex pump <37.5 Positive displacement pump <850 Counter pump <800 Rotary piston pump 200 ~ 10000 Single screw pump 10 ~ 560000 Double screw pump 0.6 ~ 100000 Three screw pump 21 ~ 600 Gear pump <2200 4.3.1 Suction tank structure type and pump suction pipe should be arranged so that the parallel pump can be the same amount of liquid inhaled, Pump suction volume in the suction liquid pool should have a certain depth of submergence, from the bottom of a certain degree of dangling height. 4.3.2 suction liquid inlet pipe, return pipe, waste collection pipe to stay away from the suction pump nozzle to prevent the bubble has not disappeared when the pump was inhaled. At the same time suction tube can not be placed in the central pool, not too close to the pool wall, generally more than 1.5D from the pool wall, in order to avoid vortex or taking the time. Ensure that the pipe joints sealed well to avoid air leakage. Suction piping arrangement should avoid the formation of air bags. 4.3.3 When conveying liquids containing solid particles, the solid particles suspended in the liquid do not absorb, store or transfer energy as liquids do, nor transfer the kinetic energy to the liquid. The presence of solid particles make the pump head, the efficiency is lower than the transport of water. 4.3.4 Transport easily vaporized liquid, the main consideration of the characteristics of easily vaporized liquid on the pump: 4.3.4.1 high pump inlet pressure 4.3.4.2 Vapor pressure drastic changes with temperature. 4.3.4.3 Strict requirements on the shaft seal of the pump and the effect of suction pressure on the vaporization of the material. 4.3.5 For conveying liquids that are not to be leaked, use a hermetically sealed pump (magnetically driven pump and shielded pump) or a mechanical seal pump with leak collection, alarm and other devices. Magnetically driven pump compared to shielded pump: Item Magnetically driven pump shielded pump Isolation sleeve (or shield) Thickness 3 times the thickness of the shield pump Shield sleeve Isolation sleeve (or shield sleeve) Consequences of damage Media leakage to the atmosphere There is a second leak-proof Set (motor housing) to prevent leakage of medium to the atmosphere, but easy to damage the motor stator Keywords: chemical pump selection Previous: Solar heat pump technology and heating applications Next: Innovation ability to enhance Zhejiang to "manufacturing strong Province "corner Related links · Solar heat pump technology and its heating applications · New Germany industrial pump company through the identification of new high-temperature screw pump · Domestic valve industry urgently needed high-precision science and technology support · Concrete pump failure cause and troubleshooting tube plugging · Jet pump Application in Process Lubrication System and Vacuum Test Type Applicable Viscosity Range mm2 / s Vane pump Centrifugal pump <150 Vortex pump <37.5 Positive displacement pump <850 Metering pump <800 Rotary piston pump 200 ~ 10000 Single screw pump 10 ~ 560000 Twin screw pump 0.6 ~ 100000 Three screw pump 21 ~ 600 Gear pump <2200 Items Magnetic drive pump Shield pump Isolation sleeve (or shield sleeve) Thickness 3 times the thickness of shielding shield Shielding sleeve (or shielding sleeve) Consequences of damage The leakage of medium to the atmosphere There is a second anti-leakage sleeve (motor housing) to prevent leakage of medium to the atmosphere, but easy to damage the motor stator Keywords: chemical The choice of pump 上 一篇: Solar heat pump technology and its heating applications 下 一篇: Innovative ability to enhance Zhejiang to "manufacturing province" turn Related links · Solar heat pump technology and its heating applications · New Germany industrial pump company new High-temperature screw pump through the identification · The domestic valve industry is in urgent need of high-precision science and technology support · Concrete pump fault tube plugging causes and troubleshooting · Jet pump in the process of lubrication system and the application of vacuum test