Analysis of Causes of Non-watering of Multi-stage Slurry Pump

In the process of using a multi-stage slurry pump, the most frequently encountered problem is that the slurry pump does not discharge water. Then, when such a failure occurs, how should we handle it? Let's take a look with Xiao Bian!

Analysis of Causes of Non-watering of Multi-stage Slurry Pump

(a) Air in the inlet pipe and pump body:

(1) The water pump is not filled with enough water before it starts. Sometimes it seems that the water has overflowed from the air outlet hole, but the air has not been turned and the air is completely discharged, causing a little air to remain in the inlet pipe or the pump body.

(2) The horizontal section of the inlet pipe in contact with the water pump shall be applied with a descending gradient of more than 0.5% in the direction opposite to the direction of the water flow. The end connected to the pump inlet shall be the highest and shall not be completely horizontal. If it is lifted upwards, air will remain in the inlet pipe, which will reduce the degree of vacuum in the pipes and the water pump, affecting water absorption.

(3) a filler pump wear due to prolonged use or have been cut through the packing loose, causing a large amount of water discharged from the gap filler and the sleeve shaft, as a result of outside air enters the interior of the pump from the gaps, Affected the lifting of water.

(4) The water inlet pipe has holes due to long-term potential underwater and corrosion of the pipe wall. After the water pump works, the water surface continues to drop. When these holes are exposed to the water surface, air enters the water inlet pipe from the hole.

(5) There is a crack at the elbow of the inlet pipe, and there is a slight gap between the inlet pipe and the pump, which may cause air to enter the inlet pipe.

(b) The pump speed is too low:

(1) Human factors. Some users were arbitrarily coupled with another motor due to the damage of the original motor, resulting in the consequences of small flow, low head, and no watering.

(2) The mechanical failure of the pump itself. The loosening of the impeller or the pump shaft fastening nut or the deformation and bending of the pump shaft causes the impeller to move more and more, directly rubbing against the pump body, or damaging the bearing, which may reduce the pump speed.

(3) The maintenance of the power machine is not working. The motor is lost due to the windings burned out, and the number of windings, wire diameters, and wiring methods in the maintenance, or failures in the maintenance that are not completely eliminated also cause the pump speed to change.

(c) The suction range is too large:

Some of the water sources are deeper, and some of the water sources have flatter peripheral areas, and the pump's allowable suction range is neglected. As a result, there is little or no water absorption. To know that the degree of vacuum that can be established at the suction port of the pump is limited, the absolute vacuum suction is approximately 10 meters of water column height, and the pump cannot establish an absolute vacuum. Moreover, if the vacuum degree is too large, the water in the pump is easily vaporized, which is unfavorable to the work of the water pump. Therefore, each centrifugal pump has its maximum allowable suction range, generally between 3-8.5 meters. The installation of the pump must not be simple and convenient.

(4) The resistance loss in the water inlet and outlet pipes is too large:

Some users have measured, although the vertical distance from the reservoir or water tower to the source water surface is also slightly less than the pump lift, but the amount of water is still small or can not mention the water. The reason is often that the pipeline is too long, the water pipe bends more, and the resistance loss of the water flow in the pipeline is too large. The reason is often that the pipeline is too long, the water pipe bends more, and the resistance loss of the water flow in the pipeline is too large. In general, the 90-degree elbow has a greater resistance than the 120-degree elbow, and each 90-degree elbow has a loss of about 0.5-1 m. The resistance of a 20-meter pipeline can cause a loss of about 1 m in the head. In addition, some users are also free to enter and exit the pipe diameter of the pump, which also has a certain impact on the lift.

(E) Other factors:

(1) The bottom valve cannot be opened. It is usually due to the long time for the pump to stand, the bottom valve gasket is sticky, and the bottom valve without the gasket may rust.

(2) The bottom valve filter net is blocked; or the bottom valve can cause blockage of the filter in the sludge layer.

(3) The impeller wears badly. Impeller blades wear over a long period of use, affecting the performance of the pump.

(4) Gate valve failure or blockage of the check valve will result in reduced flow or even failure to catch water.

(5) The leakage of the outlet pipe will also affect the amount of water pumped.