Expert Yogi
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| 1. Pipeline centrifugal pumps are matched with some pipeline centrifugal pumps. Users believe that this can increase the actual head, but in fact, the actual head of the water pump is equal to the total head to the loss head. After the water pump model is determined, the total head is fixed; The loss of head mainly comes from pipeline resistance. The smaller the pipe diameter, the greater the resistance, and therefore the greater the loss of head. Therefore, reducing the pipe diameter not only does not increase the actual head of the water pump, but also reduces it, leading to a decrease in pump efficiency. Similarly, when a small diameter water pump uses a large water pipe for pumping, the actual head of the pump will not be reduced. Instead, the loss head will be reduced due to the decrease in pipeline resistance, resulting in an increase in actual head.
2. High head water pumps are used for low head pumping. Some pipeline centrifugal pumps users believe that the lower the pumping head, the smaller the motor load. Under the misleading misconception, when choosing a water pump, the head of the pump is often chosen too high. In fact, for centrifugal pumps, when the pump model is determined, the power consumption is directly proportional to the actual flow rate of the pump. The flow rate of the water pump will decrease with the increase of the head, so the higher the head, the smaller the flow rate, and the smaller the power consumption. On the contrary, the lower the head, the greater the flow, and the greater the power consumed.
3. If there are too many elbows on the inlet pipeline of the centrifugal pump in the pipeline, it will increase local water flow resistance. And the elbow should turn in the vertical direction, and it is not allowed to turn in the horizontal direction to avoid gathering air.
4. When installing the water inlet pipeline, the horizontal section should be horizontal or upward. This will cause air to accumulate in the water inlet pipeline, reduce the vacuum degree of the water pipe and water pump, and reduce the suction head and water output of the water pump. The correct approach is to tilt the horizontal section slightly towards the direction of the water source, not horizontally, and not upward.
5. The inlet of the pipeline centrifugal pump is directly connected to the elbow, which will cause uneven distribution of water flow when passing through the elbow and entering the impeller. When the diameter of the inlet pipe is greater than that of the water pump inlet, an eccentric reducing pipe should be installed. The flat part of the eccentric reducer should be installed above, and the inclined part should be installed below. Otherwise, air will accumulate, water output will decrease or water cannot be pumped, and there will be a sound of impact. If the diameter of the inlet pipe is equal to that of the water pump inlet, a straight pipe should be added between the water pump inlet and the elbow, and the length of the straight pipe should not be less than 2-3 times the diameter of the water pipe.
6. If the outlet of the pipeline centrifugal pump is above the normal water level of the outlet pool, although the pump head is increased, the flow rate is reduced. If the water outlet must be higher than the water level of the water tank due to terrain conditions, elbows and short pipes should be installed at the pipe mouth to make the water pipe a siphon type and reduce the height of the water outlet.
7. When installing the bottom valve, the lower section of the inlet pipe is not vertical. If installed in this way, the valve cannot close on its own, causing water leakage. The correct installation method is to install the inlet pipe with a bottom valve, and ensure that the next section is vertical. If vertical installation is not possible due to terrain conditions, the angle between the water pipe axis and the horizontal plane should be above 60 °.
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Misunderstandings in the operation and use of pipeline centrifugal pumps
