Application selection of centrifugal pump
by:J&T
2021-02-20
1. Cavitation phenomenon of centrifugal pump The cavitation phenomenon of centrifugal pump refers to the partial vaporization of the liquid to be transported because the saturated vapor pressure at the transport temperature is equal to or lower than the pressure at the pump inlet (actually at the blade inlet), causing the pump Noise and vibration are generated. In severe cases, the flow rate, pressure head and efficiency of the pump will drop significantly. Obviously, cavitation is not allowed in the normal operation of the centrifugal pump. (2) Under the condition of ensuring the maximum flow area, the flow cross-section shape of the valve globe cover should be streamlined as much as possible to reduce the flow resistance. (3) When designing the structure of the plunger, the suction port at the lower end of the plunger should be designed to be streamlined or bell-mouthed to reduce its suction resistance. While ensuring that the plunger outlet has the largest flow cross-section, the plunger outlet flow channel is also designed to be streamlined to reduce the flow resistance at the plunger outlet. The key to avoiding cavitation phenomenon is to install the water pump at the correct height, especially when transporting volatile liquids with higher temperatures. Substituting the Hs1 value into the equation to obtain the installation height Hgu003dHs1-Hf0-1u003d0.78-1.5u003d-0.72m Hg is a negative value, which means that the pump should be installed below the liquid level of the pool, at least 0.72m lower than the liquid level. 2. The installation height of the centrifugal pump Hg Allowable suction vacuum height Hs refers to the maximum vacuum that can be reached by the pressure p1 at the pump inlet. The actual allowable suction vacuum height Hs value is not calculated according to the formula, but by the pump The value determined experimentally by the manufacturer, this value is attached to the pump sample for users to check. It should be noted that the Hs value given in the pump sample is the value when clean water is used as the working medium, and the operating condition is 20℃ and the pressure is 1.013×105Pa. When the operating conditions and working medium are different, conversion is required. (1) Transporting clean water, but the operating conditions are different from the experimental conditions, can be converted according to the following formula Hs1 u003d Hs + (Ha-10.33)-(Hυ-0.24) (2) When transporting other liquids, the conditions of the transported liquid and the villain are the same as those of the experiment When the conditions are different, a two-step conversion is required: the first step is to convert Hs1 from the pump sample according to the above formula; the second step is to convert Hs1 to H's NPSH Δh according to the following formula. For oil pumps, use steam when calculating the installation height. Calculate the eclipse margin Δh, that is, use the cavitation margin Δh to check from the oil pump sample, and its value is also measured with 20℃ clean water. If other liquids are to be transported, calibration is also required. Check the relevant books. From a safety perspective, the actual installation height of the pump should be less than the calculated value. Also, when the calculated Hg is negative, it means that the suction port of the pump should be below the liquid level of the storage tank. Water pump factory, water pump factoryu003c/pu003e
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The Global submersible pump Leader. J&T INDUSTRY CO.,LTD. will build a unique portfolio of JT and related brands, striving to surpass our competitors in quality, innovation and value, and elevating our image to become the submersible pump company most customer turn to worldwide.
submersible pump can be applied in different ways as pool cover drain pump.
To that end, J&T INDUSTRY CO.,LTD. has successfully built a solid foundation and infrastructure for submersible pump manufacturing.
The Global submersible pump Leader. J&T INDUSTRY CO.,LTD. will build a unique portfolio of JT and related brands, striving to surpass our competitors in quality, innovation and value, and elevating our image to become the submersible pump company most customer turn to worldwide.
submersible pump can be applied in different ways as pool cover drain pump.