Some pipeline centrifugal pump users think that this can increase the actual head. In fact, the actual head of the pump = total head ~ loss head. When the pump model is determined, the total head is fixed; the loss head mainly comes from the pipeline resistance, the smaller the pipe diameter is, the greater the resistance is, so the loss head is greater, so after reducing the pipe diameter, the actual head of the water pump cannot be increased. , On the contrary, it will decrease, resulting in a decrease in the efficiency of the water pump. In the same way, when a small-diameter water pump uses a large water pipe to pump water, the actual head of the pump will not be reduced. On the contrary, the loss of the head will be reduced due to the decrease in the resistance of the pipeline, and the actual head will be increased. They also think that when a small-diameter water pump uses a large water pipe to pump water, it will inevitably increase the motor load. They believe that as the pipe diameter increases, the water in the outlet pipe will exert greater pressure on the pump impeller, which will greatly increase the motor load. As everyone knows, the size of the liquid pressure is only related to the height of the head, and has nothing to do with the cross-sectional area of ​​the water pipe. As long as the head is constant, the size of the impeller of the pump remains the same, and the pressure acting on the impeller is constant regardless of the pipe diameter. Only after the pipe diameter increases, the water flow resistance will decrease, and the flow will increase, and the power consumption will also increase appropriately. But as long as it is within the rated head range, the pump can work normally no matter how the pipe diameter is increased, and it can also reduce the pipeline loss and improve the pump efficiency.