How to choose a screw pump

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1. Determine the speed range based on the viscosity of the conveying medium and the specifications of the pump.: Heat exchanger manufacturers, when transporting high-viscosity media, the pump should choose a low speed. If the viscosity is low, a high speed can be selected accordingly.: For large-sized pumps (main rod outer diameter above 60mm), when the medium viscosity is >20°E, the rotation speed is preferably 970rpm or 720rpm. If the viscosity is higher (viscosity>80°E), such as viscose liquid, the rotation speed can be reduced, and 200-500rpm is recommended. ； For small-sized pumps, when the medium viscosity is >20°E, the rotation speed is preferably 1450rpm or 970rpm. If the viscosity is higher (viscosity>80°E), the rotation speed can be reduced, and 300-600rpm is recommended. 2. Because the higher the speed of the pump, the smaller the volume of the pump will be under the same performance parameters. However, due to the high speed and high friction power, the wear of the pump will be greater and the life will be shorter. If the lubrication of the conveying medium is poor or contains trace impurities, a lower speed should be selected to maintain a longer life of the pump. It is recommended to be below 1450 rpm. 3. The selection of structure can be carried out according to the installation and use conditions of the pump by referring to the series and type of the three-screw pump. In principle: To transport lubricating oil, choose a pump with built-in bearing structure when the temperature is below 80°C. 4. When the temperature exceeds 80°C or the conveyed medium has poor lubricity, choose a pump with an external bearing structure. 5. When transporting media with poor fluidity and high viscosity or when the transported media needs to be heated or kept warm, choose a pump with a double-layer heating pump body structure. 6. When transporting at high temperatures, pumps made of high-temperature resistant materials should be selected.