Analysis Of The Reasons Why The Single Screw Pump Does Not Produce Water

(1) The horizontal section of the water inlet pipe in contact with Single Screw Pump should have a downward slope of more than 0.5% against the direction of water flow, with the end connected to the inlet of the single screw pump being the highest. Do not make it completely horizontal. If it tilts upward, air will remain in the water inlet pipe, reducing the vacuum in the water pipe and the single screw pump, affecting water absorption.

(2) The single screw pump is not filled with enough water before starting. Sometimes it seems that the water has overflowed from the vent hole, but the pump shaft is not turned to completely discharge the air, resulting in a small amount of air remaining in the water inlet pipe or pump body.

(3) The water inlet pipe has been submerged underwater for a long time, and holes appear on the pipe wall due to corrosion. After the single screw pump is working, the water level continues to drop. When these holes are exposed to the water surface, air enters the water inlet pipe through the holes.

(4) The packing of the single screw pump has been worn out due to long-term use or the packing is too loose, causing a large amount of water to spray out from the gap between the packing and the pump shaft sleeve. As a result, external air enters the interior of the single screw pump through these gaps, affecting water pumping.

(5) Cracks appear at the bend of the water inlet pipe, and a small gap appears at the connection between the water inlet pipe and the single screw pump, which may allow air to enter the water inlet pipe.

The speed of the single screw pump is too low

(1) Mechanical failure of the single screw pump itself. The impeller and pump shaft fastening nut is loose or the pump shaft is deformed and bent, causing the impeller to move more, directly rub against the pump body, or the bearing is damaged, which may reduce the speed of the single screw pump.

(2) Human factors. Some users arbitrarily match another motor to drive the original motor because it is damaged, resulting in low flow and head or even no water supply.

(3) The power machine is not properly maintained. The motor loses magnetism due to winding burnout. Changes in the number of winding turns, wire diameter, and wiring method during maintenance, or failure to completely eliminate faults during maintenance will also cause the speed of the single screw pump to change.

The suction range is too large

Some water sources are deep, and the outer terrain of some water sources is relatively flat, but the allowable suction range of the single screw pump is ignored, resulting in less water suction or no water suction at all. It should be known that the vacuum that can be established at the water inlet of the single screw pump is limited. The suction range of absolute vacuum is about 10 meters of water column height, and it is impossible for a single screw pump to establish an absolute vacuum. Moreover, if the vacuum is too large, it is easy to gasify the water in the pump, which is not conducive to the operation of the single screw pump. Therefore, each centrifugal pump has its maximum allowable suction range, generally between 3-8.5 meters. When installing a single screw pump, you must not only seek convenience and simplicity.

The resistance loss of water flow in the inlet and outlet pipes is too large.

Some users have measured that although the vertical distance from the reservoir or water tower to the water source is slightly less than the head of the single screw pump, the water volume is still small or no water can be lifted. The reason is often that the pipeline is too long, the water pipe has many bends, and the water flow has too much resistance loss in the pipeline. The reason is often that the pipeline is too long, the water pipe has many bends, and the water flow has too much resistance loss in the pipeline. Generally speaking, the resistance of a 90-degree bend is greater than that of a 120-degree bend. The head loss of each 90-degree bend is about 0.5-1 meter, and the resistance of each 20-meter pipeline can cause a head loss of about 1 meter. In addition, some users also arbitrarily change the diameter of the inlet and outlet pipes of the single screw pump, which also has a certain impact on the head.

Influence of other factors

(1) The bottom valve cannot be opened. Usually it is because the single screw pump has been shelved for too long, the bottom valve gasket is stuck, and the bottom valve without a gasket may rust.

(2) The impeller is severely worn. The impeller blades are worn out after long-term use, affecting the performance of the single screw pump.

(3) The filter screen of the bottom valve is blocked; or the filter screen is blocked by the sludge layer in the bottom valve.

(4) The gate valve or check valve is faulty or blocked, which will cause the flow rate to decrease or even stop pumping water.

(5) Leakage in the outlet pipe will also affect the water extraction volume.