Screw pump fault diagnosis

honey pump for sale, Screw pump fault

The screw pump is a new type of mechanical tool for transporting liquids. It has the advantages of simple structure, safe and reliable operation, convenient use and maintenance, continuous and uniform medicine dispensing, and stable pressure. Screw pumps are widely used in the transportation of flocculant solutions in mineral processing and concentration. The flocculant has the characteristics of high viscosity and difficulty in transportation. At the same time, the molecular chain of the flocculant can be transported intact without being damaged, making the screw pump an inevitable choice. The continuous and stable operation of the mineral processing system requires that the addition of flocculant must be an uninterrupted process. Therefore, the continuous operation of the screw pump and the timely determination and treatment of screw pump failures have become key.

1. Structure and working principle of screw pump transmission device

The screw pump transmission device is a single-screw transport pump. Its main working components are the screw of the eccentric helix and the screw bushing with a double-line helical inner surface. Its working principle is that when the motor drives the pump shaft to rotate, the screw On the one hand, it rotates around its own axis, and on the other hand, it rolls along the inner surface of the bushing, thus forming a sealed chamber of the pump. Every time the screw rotates once, the liquid in the seal cavity pushes forward by one pitch. As the screw continues to rotate, the liquid is pressed from one seal cavity to another in a spiral manner, and finally squeezes out of the pump body.

2. Analysis and treatment of screw pump faults

2.1 The screw pump body vibrates violently and makes noise

During the operation of the screw pump, the pump body vibrates violently, and at the same time, regular abnormal noises are made in the cavity of the pump body. The reasons for this type of failure are as follows:

(1) The screw pump is a positive displacement pump. The inlet valve is blocked by some lumps or large agglomerates sucked in, which makes the drainage not smooth and causes
The pump is idling or the flow is uneven and the pipeline is vibrating.

(2) There is air leakage in the suction pipeline or the suction end of the screw pump.

(3) The suction height exceeds the suction vacuum height of the pump.

In order to avoid severe vibration and abnormal noise failure of the screw pump during operation, the flocculant should be completely dissolved in the tank to avoid agglomeration. At the same time, the bottom of the flocculant preparation box should be cleaned regularly to ensure that there is no impurity. things exist. Before starting the pump each time, the inlet and outlet valves need to be opened, otherwise it will easily cause pipeline vibration and cause a large amount of liquid circulation in the pump, and the high temperature will cause damage to the pump. Clear the air leakage blockage in time, reduce the suction height and reduce the pipeline resistance.

2.2 The drive shaft of the screw pump is overheated or the motor bearing is overheated

The overheating of the transmission shaft of the screw pump or the overheating of the motor bearing may be caused by a lack of oil in the bearing part, or the screw pump may be empty, causing idling, or the dry friction between the rotor and the stator may cause the pump body to overheat. Overheating of the pump body transmission shaft and motor bearings can cause damage to the screw pump bearings, and long-term idling operation can cause irreparable damage to the screw and cavity. During the operation of the screw pump, there must be enough grease in the parts, but not too much. At the same time, when the pump body overheats, the pump should be stopped immediately for inspection, and dry operation of the screw pump is strictly prohibited.

2.3 Decrease in flow rate of screw pump

The flow rate decreases or the flow rate disappears during the operation of the screw pump. The reasons are as follows:

(1) The inlet pipeline is leaking or blocked.

(2) The speed of the screw pump is low.

(3) The screw bushing is worn.

(4) Shaft seal leaks.

If the flow rate decreases due to air leakage or blockage in the inlet pipe, the suction inlet of the screw pump is not enough, which may easily cause the pump to be empty. The screw pump is accompanied by vibration or abnormal noise, and the inlet pipe needs to be disassembled for inspection. If the flow rate drops due to insufficient pump speed, there will be abnormal noise from the motor, and the motor circuit needs to be checked. If the flow rate decreases due to screw bushing wear, it can be judged by increasing the frequency of the screw pump. If the flow rate still does not increase after the frequency is increased, the possibility of bushing wear can be ruled out. The judgment of flow decrease caused by shaft seal leakage is more intuitive and can be determined directly.

2.4 The pressure of the pressure gauge on the outlet pipeline of the screw pump fluctuates greatly.

When the outlet pressure of the screw pump fluctuates greatly, it is often accompanied by large fluctuations in the outlet flow rate, which not only cannot meet the requirements of the production process, but also a large range of pressure fluctuations is an obvious signal of screw pump failure. If the fault is not found and repaired in time, Repairs will lead to the rapid expansion of the accident. If the pressure fluctuation is accompanied by abnormal suction noise of the screw pump, it means that the screw pump is not capable of filling the capacity. The inlet of the pump must be blocked or not tightly sealed, and the pump should be stopped immediately for inspection.

In addition, large pressure fluctuations may also be caused by intermittent jamming of the screw. To determine whether jamming occurs during the operation of the screw pump, you only need to observe the leakage part of the transmission shaft. If the screw pump is stuck, it must be stopped immediately and the screw pump must be disassembled and inspected.

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