Correct use of slurry pump in coal washing plant

1、Slurry pump in coal washing plant

With the progress of coal washing（https://www.lianranpump.com/） technology, especially the promotion of heavy medium and flotation coal selection technology, and the popularization of closed-loop washing water circulation, the slurry pump has become an indispensable equipment in various process links due to its excellent hydraulic performance, high efficiency, and reliable operation. The performance of slurry pumps has a crucial impact on the production of coal preparation plants. The correct use of slurry pumps is the primary prerequisite for ensuring performance.

2、 Correct use of slurry pump

1. Reasonable selection ensures that the pump operates under suitable working conditions, with head, flow rate, and shaft power being the three key elements of pump selection. Reasonable selection based on the characteristics of the working conditions is a prerequisite for the normal and efficient operation of the pump. At the same time, the maximum slurry weight, concentration, and particle characteristics that each slurry pump can transport are easily overlooked. When using it on site, it should be ensured that it operates within the allowable range of the pump, Excessive concentration can cause excessive resistance in the feed pipe and, in severe cases, damage to individual parts of the pump. Exceeding the maximum particle size allowed by the pump will block the impeller flow passage, cause vibration, and may damage the flow components. Therefore, the pump should be selected reasonably based on the working conditions or the inlet tank barrier should meet the particle requirements that the pump can pass through.

2. Correct operation and compliance with pump operating specifications

(1) Before initial operation, check that the rotation direction of the motor is consistent with the specified rotation direction of the pump (please refer to the corresponding model manual). When testing the direction of motor rotation, the motor should be tested separately and should not be connected to the pump for testing. Check if the elastic pad in the coupling is complete and correct. Check if the rotation of the motor shaft and pump is concentric. There should be no tightness or friction when using hand cranked pumps (including electric motors). Check if bearing oil (L-FC46 or L-FC68) has been added to the bearing housing to the indicated position on the oil gauge. Before starting the pump, the shaft seal water (mechanical seal is cooling water) should be opened, and the pump inlet valve should be opened and the pump outlet valve should be closed. Check if the valve is flexible and reliable, such as anchor bolts, flange gaskets, and bolts. Whether the pipeline system is installed correctly, firmly and reliably

(2 )Daily start-up and operation precautions for pumps

1 Before starting the slurry pump, the inlet valve of the pump should be opened, the outlet valve of the pump should be closed, and then the pump should be started. After starting the pump, slowly open the pump outlet valve The size and speed of the pump outlet valve should be controlled by ensuring that the pump does not vibrate and the motor does not exceed the rated current.

2 The starting of pumps used in series also follows the above method. After starting the first stage pump, the outlet valve of the final stage pump can be opened one point (the appropriate size should be 1/4 of the rated current of the first stage pump motor), and then the second and third stages can be started successively until the final stage pump. After all the series pumps are started, the outlet valve of the final stage pump can be gradually opened. The speed of valve opening should be controlled by the pump not vibrating and the motor of any stage pump not exceeding the rated current.

3 Avoid the pump running without the high-pressure air duct closed. The slurry pump used in coal preparation plants is usually equipped with a high-pressure air duct near the feed tank on the feed pipe. The high-pressure air duct is used to drum up the material that sinks due to pump shutdown, to avoid the feed port being blocked by the material after starting the pump and unable to load. If the high-pressure air duct is not closed or not tightly closed during use, it can cause high-pressure air to be present in the material. Due to the low inlet pressure of the pump, the gas expands in the feed pipe and enters the high-pressure area through the impeller, rushing towards the volute and lining plate, causing increased wear and tear. In severe cases, it can cause the volute or lining plate to break.

4 The slurry pump in the coal preparation plant is basically installed by injection method. During normal operation of the centrifugal pump, the absolute pressure in the water flow at the pump inlet will inevitably decrease, and the minimum pressure zone will appear near the inlet edge of the impeller. This minimum pressure zone varies with the external environment.