According to incomplete statistics, accidents caused by electromechanical equipment in coal mine production in my country account for more than 50% of the total number of coal mine accidents. In addition to the poor design and manufacture of the pump itself, many of the faults caused by the operation of the strong drainage pump in the coal mine are due to the improper device design of the user unit, unreasonable installation and piping construction, insufficient preparation for operation, inaccurate operation and maintenance Negligence in maintenance, etc. The safe use of coal mine strong drainage pumps is very important.
1. Coal mine strong drainage pump assembly
Coal mine strong drainage pumps should generally be disassembled for inspection before installation in the mine, and then reassembled. The assembly of the pump must strictly follow the instructions provided by the manufacturer.
2, installation of coal mine strong drainage pump
(1) Mine, pump room and pipeline system requirements. Each mine must be equipped with 3 or more water pumps, two or more drainage pipelines, and the installation of electrical and mechanical equipment in the water tank and pump room must comply with Article 278 of the "Coal Mine Safety Regulations") It is stipulated that the electrical part should comply with Article 442 of the Coal Mine Safety Regulations)). The installation position of the water pump should meet the requirements of the allowable vacuum height, the installation foundation must be level and stable, and the reserved holes on the foundation should be poured according to the size of the water pump. If there are multiple units in the same machine room, there should be a distance of more than 800mm between the unit and the unit and between the unit and the wall.
The inlet pipe diameter of the water pump in the piping system should be 1 to 2 gears larger than the pump inlet, and the outlet pipe diameter should not be smaller than the pump outlet. The specific specifications of the inlet and outlet pipes should be determined by calculating the optimal flow rate and strict economic comparison. . The importance of the pump inlet pipe is greater than that of the outlet pipe. The inlet pipe must have good sealing and shorten the length as much as possible (but it is best to have a straight pipe section 4 times the diameter in front of the pump inlet), and reduce valves and The number of pipe components such as elbows and reducers. If there are elbows, the bending radius of the elbow should be increased as much as possible. At the same time, in order to prevent air from collecting in the water inlet pipe during operation, it is generally required that the water inlet pipe is slightly inclined and The inlet of the water pump is connected, and the suction port of the inlet pipe should be guaranteed to have a certain submerged depth. The water inlet depth of the bottom valve must be greater than 1,5 times the diameter of the inlet pipe. The distance between the suction port and the pool bottom and wall is preferably greater than 0.75m. The minimum should not be less than 0.5m (because of coal lump will accumulate). In addition, the inlet port of the water inlet pipe should be equipped with a filter device. All pipelines connected to the pump should have independent and firm supports to reduce the vibration of the pipeline and prevent the weight of the pipeline from pressing on the pump. In terms of instrument installation, the vacuum gauge should not be placed at the elbow of the inlet pipe, nor too close to the jet pump. It is best to install the inlet straight pipe at a place twice the diameter of the pump inlet flange, or at the pump flange. There should be a valve in front of the vacuum gauge to disconnect the pressure. The pressure gauge is generally placed at the flange of the outlet section of the pump. The pressure gauge range must have a certain margin. The pressure gauge should also be equipped with a valve that can be closed and a buffer device to stabilize the reading.
(2) The installation requirements of coal mine strong drainage pumps are generally connected by couplings. At this time, ensure that the shaft centers are on the same straight line, and the alignment should be based on the axis of the pump to prevent the unit from running. Vibration and wear on one side of the bearing. The coupling should have a certain gap: in the pump axially behind the motor, in principle, the gap between the two couplings depends on the allowable wear of the pump's balance mechanism. Mine drainage pumps are generally 5-8mm.
3. Coal mine strong drainage pump operation
Before running, check and ensure that the rotation direction of the motor is consistent with the rotation direction of the water pump. If water is drawn by vacuum, the vacuum gauge should be opened (observed). If a bottom valve is installed, the vacuum gauge will be closed when filling water (anti-positive pressure). When diverting water, it is necessary to ensure that the water inlet pipe and the pump cavity are filled with the delivery liquid. Do not start without liquid!
Before starting, make sure that the cooling water pipeline of the balance plate should be unblocked. Start the pump and observe the pressure gauge to check whether the pressure is built up. Gradually open the outlet valve to the rated working condition. The valve closing time should not be long when starting. No more than 2~3min, otherwise, the temperature rise will cause vaporization, which will damage the pump. Remember: the centrifugal pump should not run for a long time with the outlet valve fully closed; nor should it run at the hump in the performance curve. During operation, the valve on the inlet pipe should be fully opened. Always pay attention to the following points during operation:
1) Observe the ammeter, listen to the sound, and judge whether the operation is normal.
2) Pay attention to whether the motor is overloaded, and it is strictly prohibited to run the motor over current.
3) Observe the leakage at the shaft seal and adjust it. Sometimes the injected water needs to be adjusted. It is better to use continuous drops.
4) Check whether the oil ring of the sliding bearing rotates. The temperature of the rolling bearing should be less than 75°C.
5) Regularly check the gap between the two couplings, and replace the balance device when they are close to each other.
6) Observe the water outlet temperature of the balance pipe. When the water temperature rises quickly, stop the pump to check whether the balance pipe is blocked.
7) Observe the pressure gauge and vacuum gauge. When the gauge pressure of the two gauges is abnormal, find out the cause in time.
8) Observe the water level to prevent no load.
9) When the water level is low, pay attention to whether the two shaft seals will suck air into the pump.
10) Pay attention to the operating conditions and cooling water conditions of the pump.
11) Keep records and shift shift system.
When stopping, the key is to turn off the pressure gauge and vacuum gauge first, then close the water outlet valve and then stop the pump.
4, coal mine strong drainage pump detection
The installation and maintenance conditions of underground mine equipment are far worse than that of the ground, and the failure and accident rate is much higher than that of ground equipment. Therefore, the necessary performance testing of underground equipment should be carried out regularly. The safety performance inspection and inspection period of the general mine main drainage pump is 1 year. When the mine drainage pump has one of the following conditions, it should be tested and inspected, and can be put into use only after passing the test and inspection:
1) Newly purchased, newly installed, or overhauled and modified.
2) Serious damage has been repaired.
3) A safety hazard is discovered during production.
4) Those that have been idle for more than one year.
5) Natural disasters (water, fire, gas, earthquake, etc.) may affect the strength, rigidity, stability, safety and other safety technical performance of product components.
5. Maintenance of coal mine strong drainage pump
Keeping the mine drainage pump in a good technical condition is the basic guarantee condition for the normal production of the mine. After the pump has been running for a period of time, its performance may be reduced to the level that cannot meet the requirements. At this time, some minor repairs and overhauls must be carried out. Minor repairs generally include: replacement of balance plates, balance replacement, replacement of bushings and fillers, adjustment of bearing bushes, etc., generally within 24h. It is generally believed that the pump must be disassembled and repaired as a whole, and the pump can be fully restored to its original performance, which is called an overhaul. It is more difficult to work out the overhaul period of the pump. This is because it depends on the purpose of the pump, the structure and material of the pump, the liquid being transported, the operating conditions and the environment, as well as overhaul costs and parking costs. Many factors affect the degree of production. Generally, the number of overhauls should be small. Pump overhauls should be arranged when the performance of the pump is significantly reduced and cannot meet the requirements of the working conditions, or the next production cycle is expected to be bad and low in performance, or when it cannot be operated due to failure. The periodic arrangement is often determined based on actual experience.
