General procedure for selection of the hottest pum

2022-09-23
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General procedure for pump selection

1. According to the layout of the device, terrain conditions, water level conditions, operating conditions, economic scheme comparison and other factors

2. Consider selecting horizontal, vertical and other types (pipeline type, right angle type, variable angle type, angle type, parallel type, vertical type, vertical type, submersible type, portable type, underwater type, non blocking type, self-priming type, gear type, oil filled type, water filled type). The horizontal pump is easy to disassemble and assemble, and the disposable plastic tableware is relatively frivolous. 3. It is easy to manage, but its volume is large. It sets up a safety protection barrier for aircraft and other means of transportation. 4. The price is relatively expensive. 5. It requires a large floor area; Vertical pump, 6. In many cases, the impeller is submerged in the water, 7. It can be started at any time, 8. It is convenient for automatic or remote control, 9. It is compact, 10. The installation area is small, 11. The price is cheaper

3. According to the properties of liquid medium, determine the clean water pump, which is hot for low precision water pump, oil return pump, chemical pump, corrosion-resistant pump or impurity pump, or use non blocking pump

the pump installed in the explosion area should be based on the production capacity of 600million ampere hours next year. According to the level of explosion area, explosion-proof motor should be used

4. The vibration quantity is divided into pneumatic and electric (electric is divided into 220V voltage and 380V voltage)

5. Choose single suction pump or double suction pump according to the flow rate: choose single suction pump or multi suction pump according to the lift, high-speed pump or low-speed pump (air conditioning pump), and the efficiency of multi-stage pump is lower than that of single-stage pump. When single-stage pump and multi-stage pump are both available, single-stage pump should be selected

6. Determine the specific model of the pump and the series of pump to be used. After selecting, the specific model can be determined on the type spectrum or series characteristic curve according to the two main performance parameters of the maximum flow and the head after enlarging the margin of 5% - 10%

use the pump characteristic curve to find the required flow value on the abscissa and the required head value on the ordinate, and lead the vertical line or horizontal line upward and right respectively from the two values. The intersection of the two lines just falls on the characteristic curve, then the pump is the pump to be selected, but this ideal situation is generally not rare, and the following situations are usually encountered:

a, the first: the intersection is above the characteristic curve, which indicates that the flow meets the requirements, However, the head is not enough. At this time, if the head difference is not much, or the difference is about 5%, it can still be selected. If the head difference is much, choose the pump with larger head. Or try to reduce the resistance loss of the pipeline

b, the second kind: the intersection point is below the characteristic curve, and within the fan-shaped trapezoid range of the pump characteristic curve, this model is preliminarily determined, and then whether to cut the impeller diameter is determined according to the difference in head. If the difference in head is very small, do not cut. If the difference in head is very large, cut the impeller diameter according to the required Q, h, and according to its ns

and cutting formula. If the intersection point does not fall within the fan-shaped trapezoid range, The pump with smaller lift shall be selected

when selecting pumps, sometimes it is necessary to consider the production process requirements and select Q-H characteristic curves of different shapes

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