During the installation of the water pump, attention should be paid to all aspects. Today, let’s talk about seven precautions for the water inlet and outlet.
1. When installing the water inlet pipe, the horizontal section is horizontal or tilted upwards
Doing so will cause air to gather in the water inlet pipe, reduce the vacuum of the water pipe and the centrifugal pump, reduce the water suction head of the centrifugal pump, and reduce the water output. The correct way is: the horizontal section should be slightly inclined toward the water source, not horizontal, and must not be tilted upwards.
2. There are many elbows on the water inlet pipe
If there are many elbows on the water inlet pipe, the local water flow resistance will increase. And the elbows should turn in the vertical direction, not in the horizontal direction, so as not to gather air.
3. Large-diameter centrifugal pumps are equipped with small water pipes to deliver water
Many people think that this can increase the actual head of the centrifugal pump. The actual head of the centrifugal pump = total head minus the lost head. When the pump model is determined, the total head is certain; the head reduction mainly comes from the pipeline resistance. The smaller the pipe diameter, the greater the resistance, and thus the greater the loss of head. Therefore, after reducing the pipe diameter, the actual head of the centrifugal pump will not increase, but will decrease, resulting in a decrease in pump efficiency.
Similarly, when a small-diameter pump uses a large water pipe to pump water, the actual head of the pump will not decrease. On the contrary, the loss of head will be reduced due to the reduction of pipeline resistance, so that the actual head will be increased. (Welcome to follow WeChat: Pump Friends Circle) Some operators believe that when a small-diameter pump uses a large water pipe to pump water, the motor load will definitely increase greatly. They believe that after 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 size of the water pipe cross-sectional area. As long as the head is constant and the impeller size of the pump remains unchanged, no matter how large the pipe diameter is, the pressure acting on the impeller is certain. It is just that when the pipe diameter is increased, the water flow resistance will decrease, and the flow rate will increase, and the power consumption will also increase appropriately. However, as long as it is within the rated head range, the water pump can work normally regardless of how the pipe diameter is increased, and it can also reduce pipeline loss and improve water pump efficiency.
4. The water pump inlet is directly connected to the elbow.
This will cause uneven distribution of water when it passes through the elbow and enters the impeller. When the diameter of the water inlet pipe is larger than the water pump inlet, an eccentric reducer should be installed. The flat part of the eccentric reducer should be installed on the top and the inclined part on the bottom. Otherwise, air will gather, the water output will be reduced or water will not be pumped, and there will be a knocking sound. If the diameter of the water 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 to 3 times the diameter of the water pipe.
5. The lowest section of the water inlet pipe equipped with a bottom valve is not vertical
If installed in this way, the valve cannot be closed by itself, causing water leakage. The correct installation method is: the lowest section of the water inlet pipe equipped with a bottom valve is preferably vertical. If it cannot be installed vertically due to terrain conditions, the angle between the water pipe axis and the horizontal plane should be above 60°.
6. The water inlet of the water inlet pipe is not in the right position.
When the water inlet depth of the water inlet pipe is not enough, it will cause vortexes on the water surface around the water inlet pipe, affecting the water inlet and reducing the water output. The correct installation method is: the water inlet depth of small and medium-sized water pumps shall not be less than 300~600 mm, and that of large water pumps shall not be less than 600~1000 mm.
7. The outlet of the water pipe is above the normal water level of the outlet pool.
If the outlet is above the normal water level of the outlet pool, although the pump head is increased, the flow rate is reduced. If the outlet must be higher than the water level of the outlet pool due to terrain conditions, an elbow and a short pipe should be installed at the pipe mouth to make the water pipe siphon-type and reduce the height of the outlet.
