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How can we make the anticorrosive centrifugal pump last longer

2021-10-11

The anticorrosive centrifugal pump is a pump used in corrosive liquids to transport corrosive liquids such as acid, alkali and salt. The price is slightly higher than ordinary ones according to the different materials. When users choose anticorrosive centrifugal pumps, how can the centrifugal pump be used more For a long time, firstly we must choose a reliable pump factory, and secondly, the use and maintenance of the pump during use. Wanjin anticorrosive pump has reliable quality, mature technology, and lifetime warranty replacement of parts, which completely solves the worries of users. The following introduces anticorrosive centrifugal pumps. How to operate and maintain it correctly during use?



Operation management and maintenance of centrifugal pumps
1. Preparation before starting
In order to ensure the safe operation of the pump, the unit should be thoroughly inspected before starting the pump, especially for newly installed pumps and pumps after overhaul, so that the problems can be dealt with in time. The main inspection contents are as follows:
1. Check whether the anchor bolts and other connecting bolts of the water pump motor are loose or fall off, if any, they should be tightened or repaired.
2. Check whether the rotor of the unit is flexible and light, and whether there is metal friction in the pump, and if so, check the reason. This inspection is often carried out by turning the coupling of the unit by hand.
3. Check whether the lubricating oil in the bearing is normal and whether the oil quality is clean.
4. Check whether the gate valve on the outlet pipe opens and closes flexibly.
5. Check whether the steering of the motor and the water pump are consistent, and whether the power supply and distribution equipment is fixed; it is an indispensable job to check the motor steering for a newly installed water pump or a water pump after an overhaul.
6. Remove the debris on the water inlet of the pump to prevent the impeller from being damaged by sucking in the debris after starting the machine.
7. Check whether the control system is normal and whether the display of each instrument is accurate. If there is remote control, check whether the remote monitoring is accurate and effective.
2. Water diversion and start-up
1. Diversion
    According to the working principle of the aforementioned centrifugal pump, water must be drawn before the centrifugal pump is started. Generally, small centrifugal pumps mostly use the method of filling and exhausting. At this time, a bottom valve should be installed at the lower end of the suction pipe. Water diversion methods include tap water irrigation, elevated tank irrigation, and exhalation pump irrigation. Most of the large and medium-sized centrifugal pumps use water ring vacuum pumps to draw air and water. When pumping air, when there is water gushing out of the exhaust pipe, it means that the suction pipe and the pump are filled with water, and the water pump can be started to work. For a self-filling pump installed below the water level of the suction pool, open the water inlet valve and the water will automatically fill the suction pipe and the pump.
2. Start
    Centrifugal water pumps are generally started by closing the gate. When starting, the operator and the crew should not get too close. When the pump speed stabilizes, the valves on the vacuum gauge and pressure gauge should be opened immediately. At this time, the reading on the pressure gauge should rise to the pump. The idling head at zero flow indicates that the pump has been pressurized. Then gradually open the gate valve on the water pressure pipe. At this time, the reading of the vacuum gauge gradually increases, the reading of the pressure gauge gradually decreases, and the reading of the ammeter on the switchboard should gradually increase. The start-up is completed when the gate valve is fully opened. When the pump is closed, the running time should generally not exceed 2~3min; if the time is too long, the water flow in the pump will continue to circulate in the pump and generate heat, causing damage to some parts of the pump.
a. If the motor is found to have only a "buzz" sound but not rotating after closing, immediately cut off the power supply and check the cause.
b. If the water pump rotates but does not produce water, stop the pump immediately to check the cause.
3. Operation management of centrifugal pump
1. After each pump unit is put into operation, the relevant record items on the daily operation report should be filled in in time. For computer management, the daily operating status data of each pump should be input into the computer's storage system.
2. The new unit uses greased ball bearings. The first oil change time will be after the unit has been operating for 80h-100h, and the oil will be changed approximately every 2400h thereafter (using molybdenum disulfide lubricant, the time can be doubled). For bearings that are lubricated by mechanical oil, the oil should be changed every 240h, and it should be noted that the oil level should be between the two scales of the oil dipstick.
3. Pay attention to whether the unit has abnormal noise and vibration. When the pump is in normal operation, the unit should be calm, and the sound should be normal and continuous without interruption. Often abnormal sound and vibration are the precursors of water pump failure. In this case, stop the machine for inspection immediately.
4. Pay attention to the inspection of the bearing temperature and oil volume of the unit. The temperature of the bearing should not exceed the ambient temperature by 30℃~40℃, and the temperature should not exceed 75℃. If there is no thermometer, you can also touch it by hand. If you feel very hot, you should stop the machine for inspection.
5. The normal dripping level of the stuffing box is generally controlled to be able to drip down, discontinuously forming a line, that is, 20 to 150 drops per minute. The amount of dripping can be controlled by loosening and tightening the packing gland. Note that it cannot be pressed unilaterally to prevent the shaft sleeve and gland from being worn.
6. For large pump units that use water-cooled bearings or circulating oil-cooled motors, the water circuit and oil circuit should be kept open. If the circulating cooling system fails, the pump should be stopped for maintenance immediately.
7. For pump units without heat preservation measures, when the pump is not running in winter, the water should be removed from the threaded pipe plug at the bottom of the pump to prevent the pump from freezing and cracking. The pump should also be used for storing water if it is not used for a long time.
8. If the water level of the water injection and suction well changes, if the water level of the suction well is lower than the design water level, one or two units should be properly shut down to avoid cavitation and damage the impeller.
9. Regularly check the coupling and the anchor bolts on the unit. If there is any deviation or looseness, it should be corrected and tightened in time.
10. Pay attention to the change of the indicator pointer. Under normal operating conditions, the position of the indicator pointer should be basically stable at a certain position. If the pointer of the instrument changes drastically and jumps, the cause should be investigated immediately. For example, if the reading of the vacuum gauge rises, it may be that the suction pipe orifice is blocked or the water level drops; the reading of the pressure gauge rises, it may be that the water pressure pipe orifice is blocked; the reading of the pressure gauge drops, it may be that the suction pipe leaks and air is sucked in, or Should the speed decrease, the impeller is blocked, etc. For the motor, pay attention to whether the reading on the ammeter exceeds the rated current of the motor. If the current is too large or too small, stop and check in time.
Four, the parking attention of the centrifugal pump
    Before stopping the centrifugal pump, first close the vacuum gauge and pressure gauge valve for the centrifugal pump, and then slowly close the gate valve on the pressure pipe to implement closed-gate shutdown.
    After stopping, pay attention to wipe off the water and sludge on the surface of the pump and the motor. After the pump is not used for a long time or after it is stopped in winter, the water in the pump casing should be drained immediately. For some problems that cannot be dealt with during operation, they should be dealt with in time after parking.
     For pumps with higher heads, attention should be paid to the possible damage caused by the water hammer when the pump is stopped. Generally speaking, the design of the water pump system has taken into account the impact of the water hammer when the pump is stopped. For the operator, it is necessary to ensure that the water hammer elimination system is intact and effective at all times, so as to stop the pump or suddenly due to failure. The effect of water hammer is effectively reduced when the pump is stopped.