Pump troubleshooting and maintenance of common faults

The basic function and function of the pump is a common mechanical equipment that transmits the liquid to the end point or increases the pressure of the liquid. The basic principle is that the driving force kinetic energy of the pump mechanical equipment or other external kinetic energy is transmitted to the liquid, so that the liquid in a certain time and space. Kinetic energy increases rapidly. As a pump worker, we should not only improve the work efficiency, reduce energy consumption and flexibly use the power energy of course in the work of the pump according to the total flow, suction, lift, motor power, water power, high efficiency and other performance parameters of the pump characteristics, but also strengthen the maintenance and maintenance of the common faults of the pump to ensure the reliable operation of the pump.

1.Pump simple fault detection method 
 
1, touch method 
 
The hand touch can monitor the temperature, vibration and void change of the equipment. The sympathetic nerve in human hands is particularly sensitive to temperature, which can accurately identify the temperature within 80 °C. By touching the parts with a handle, it can be felt whether it causes the change of impact and vibration, and the climbing condition of the skateboard. Using a thermometer equipped with a surface thermal resistance camera thermometer to accurately measure the surface temperature of flip bearings, machine tool spindle box, rolling bearings, motors and other parts, it has the ability to distinguish abnormal heat. 
 
2. Stethoscope method 
 
The role of the human auditory system can compare whether there is abnormal noise in the machine equipment, and distinguish the potential safety hazards such as collision, loosening, and imbalance inside the machine equipment. Use the hammer to moderately knock on the parts, listen to whether there is a cracking noise, and distinguish whether there is a crack. The electronic stethoscope can convert the vibration of the machine equipment into an electronic signal and expand it. The workers use mobile phone headphones to monitor the vibration and sound of the operating machine equipment to maintain accurate measurement of the sound judgment. The data signals of the same measurement point, different stages, the same speed ratio and the same working condition are measured and compared to determine whether the machine equipment has common faults.

3. Observation 
 
Human visual effects can observe whether the parts on the machine equipment have cracks, looseness, and other damage ; it can be checked whether the wetting is normal, whether there is dry friction and running, dripping, falling, leakage ; it can monitor whether everything is normal for equipment fitness exercise, and whether there are abnormal situations. Comprehensive analysis of various types of information content can distinguish common faults. 
 
2.Common problems in pump application 
 
1.When the pump pump bottom valve seepage, some people will use sandy soil to fill the pump inlet pipe, tap water to flush the valve, such practice is not desirable. When the sandy soil is put into the water inlet, the sandy soil will enter the pump when the pump starts to work. At this time, the centrifugal impeller and bearing of the pump will be destroyed, which will reduce the service life of the pump. 
 
2, if the pump has all the small common faults remember not to let its work. If the filling material of the pump shaft is completely damaged, it should be added on time. If the pump is applied again, it will leak. At the same time, the harm is that the energy consumption of the motor is increased, which will destroy the centrifugal impeller. 
 
3.If the pump in the course of the adoption of the obvious vibration at this time must be slow down to check what is going on, otherwise the same will cause damage to the pump. 
 
4.The tape on the pump also needs to be removed, and then cleaned with clean water and dried in the sun. It is not necessary to put the tape in the dark and cold area. The tape of the water pump must not be stained with oil, and do not apply some sticky items on the tape.

5. Pay special attention to the maintenance of the water pump after application. For example, when the water pump is used up, clean the water in the water pump. It is better to remove the water pipe and then clean it with tap water.

6. Carefully check whether there are cracks on the centrifugal impeller, whether the centrifugal impeller is fixed on the bearing and whether there is looseness. If there are cracks and looseness, repair immediately. If there is sand on the centrifugal impeller of the water pump, clean it up.

7. The connection between the water pump and the pipeline must be well sealed, because if dirt enters, it will cause damage to the inside of the water pump.

8. The bearing on the water pump is also the key to inspection. Check whether the bearing is damaged after use. If the water pump is used for a long time, the small steel ball in the bearing will be broken. Therefore, it is better to apply a layer of lubricating grease on the bearing after the water pump is used to maintain the water pump bearing.

3、 Causes and removal of common problems of water pump
1. Reasons and solutions for insufficient total head of pump.
reason:
(1) The motor speed is insufficient.
(2) The outlet valve is opened too large and discharged too much.
(3) The impeller fan passage is blocked.
(4) The clearance of overcurrent components in the pump is too large.
(5) The sealing ring is seriously damaged.
(6) The balance organization is seriously damaged.
(7) The pump barometer fails, the sign is prohibited or the barometer is damaged.
Solution:
(1) Find out and solve the cause of low motor speed.
(2) Operate the outlet valve to adjust the exhaust volume within the effective area.
(3) Remove the blockage in the impeller passage.
(4) Stop the pump and dismantle it. Regularly check and adjust the gaps in the pump.
(5) Remove and replace the interstage sealing ring.
(6) Stop the pump and check the equalization signal gap.
(7) Check or replace the barometer.
2. Cause and solution of bearing fever of centrifugal water pump
reason:
(1) Lack of oil or too much oil.
(2) There is residue in the bearing or bearing bush.
(3) The oil ring is stuck.
(4) The bearing bush clearance is too small, causing serious damage to the shaft.
(5) The pump shaft is bent and the bearing is inclined.
(6) The lubricating grease is not cleaned, there is residue, and the bearing (or bearing bush) leaks water.
(7) The temperature of transportation liquid is too high, which will endanger the temperature of bearing (or bearing bush).
Solution:
(1) Fill or lower the grease.
(2) Remove and replace the qualified lubricating grease.
(3) Regularly check the adjusting oil ring.
(4) Check the bearing bush or replace the grinding bearing bush.
(5) Check the pump shaft bending and bearing inclination, and carry out immediate maintenance and adjustment.
(6) Filter the grease again and clean the bearing box. (7) Reduce the temperature of transported substances.
3. There is no water inflow after the pump is started, the barometer has no reading value, and the reason and solution for the high negative pressure of the suction vacuum gauge
Key reasons:
(1) The pump inlet water pump is not started or the opening is insufficient.
(2) The gate valve of the pump inlet water pump fell down.
(3) The filter device in front of the pump is blocked by dirt.
(4) The pump inlet pipe is blocked by dirt or silt. (5) When the pump is newly built and put into production for trial operation, the pump inlet slip-on flange gasket will not be perforated.
Solution:
(1) First, fully open the pump inlet pump. If it still cannot be cleared, stop the pump, close the inlet and outlet and the outlet gate valve of the water supply pressure tank, open the safety relief valve at the pump outlet, and carry out pressure relief and venting. And open the filter valve of the filter device in front of the pump to drain the water stored in the pump and the inlet pipe section.
(2) Repair the pump inlet water pump.
(3) Remove the blocking dirt in the filter device in front of the pump and clean the filter screen.
(4) Inspect, transport and clean the silt and dirt in the inlet pipeline.
(5) Disassemble and inspect the base gasket of the imported slip-on welding flange with neck, and carry out another drilling or replace the base gasket.
4. Reasons and solutions for abnormal noise during operation after running the pump
(1) The noise is very large. With the increase of vibration, the motor current decreases and shakes, the pump pressure gauge needle shakes greatly and decreases, and the exhaust volume decreases, which is also the cavitation condition. The countermeasures of increasing the suction pressure, slowly increasing the pump pressure and reducing the exhaust volume can be adopted until the abnormal sound subsides, and the pump should be stopped immediately when it is serious.
(2) If there is little change in the "scratch" sound from the pump, all the main parameters of various operations are normal, indicating that the centrifugal impeller has slight friction with the guide vane or the middle area. The pump can continue to operate, and the sound will subside after a period of operation.
(3) There is a crash sound in the pump, the working pressure of the pump does not change much, and the electric flow expands or fluctuates. This is also because the operation is not carried out according to the safety operation regulations, or other reasons cause the collision or serious friction between the motor stator and the motor rotor, resulting in the fall of the mouth ring and shaft sleeve. At this time, it should be shut down immediately to solve the problem.
5. Causes and solutions of centrifugal pump vibration and relatively large noise
Key reasons:
(1) The pump is not emptied or the gas in the pump is not emptied before starting the pump.
(2) The centrifugal impeller, inlet pipe and filter screen are blocked, the well water is blocked, and the power supply is insufficient.
(3) The connection position of the pump inlet end or the sealing ring is not tight and there is steam leakage.
(4) The bearing bush is seriously damaged and the gap is too large.
(5) The exhaust volume of the pump is too large or too small, causing cavitation or turtle pump.
(6) The centrifugal impeller is damaged, or the motor rotor is unbalanced, causing vibration.
(7) The pump shaft is bent or the pump shaft is not of the same center, which makes the motor rotor and the motor stator rub.
(8) The equalizing disc is seriously damaged and invalid, resulting in excessive radial driving force.
(9) The basic foundation screw is fixed and unstable, or the design scheme is not installed properly.
(10) The coupling is irregular or the connecting anchor bolt is loose, and the damping rubber washer is damaged seriously, resulting in imbalance and vibration absorption.
(11) Pump vibration caused by motor vibration.
(12) The rubber supports of the inlet and outlet pipes are fixed and unstable, and the pipes are suspended in the air and cause vibration.
(13) The fixing bracket of pump bearing bush is loose or tight.
Solution:
(1) First, adjust the opening of the gate valve at the pump outlet to effectively control the working midpoint of the pump. If it is still difficult to remove, be sure to stop the pump for inspection.
(2) Open the safety relief valve at the pump outlet, drain the gas in the pump, and start the pump again.
(3) Check and remove the blockage of centrifugal impeller, inlet pipe and filter device in front of pump.
(4) Repair or replace the bearing bush and adjust its clearance to meet the technical standards.
(5) Straighten the pump shaft or pump to find the same boat again.
(6) Repair or replace the balance organization.
(7) Adjust the lifting capacity of pump bearing bush again to meet the technical standards.
(8) Check and tighten the connecting anchor bolts, and remove and replace the coupling or damping rubber washer.
(9) Check the tightening condition of the fixing bracket of the adjusting bearing bush.
(10) Operate the motor independently to eliminate the vibration.
(11) Check and tighten the foundation screws and reinstall them according to the design regulations.
(12) Check the reinforced pipe support frame.