The fault diagnosis of the rotary vane vacuum pump and the maintenance of the vacuum pump


  • What should I do if the vacuum pump fails to start?
    In the process of using the vacuum pump, whether it is a domestic vacuum pump or an imported vacuum pump, regardless of the quality, after a long time of work, if the maintenance is not performed in time and correctly, more or less failures will always occur. If the vacuum pump cannot be started normally due to long-term non-use or failure, a detailed analysis of the specific problem is required. The article mainly explains the reasons and troubleshooting methods of the vacuum pump cannot be started or cannot be started due to a fault.    1. The reasons for this failure due to the vacuum pump being unable to start are as follows:    (1) The drive motor voltage is incorrect or overloaded.   (2) Motor starter overload protection is too small or the set value is too low   (3) The fuse is blown.   (4) If the vacuum pump is equipped with an AC motor: the capacitor of the motor is damaged.   (5) Check the use of vacuum pump oil. The vacuum pump returns oil, the oil temperature is too low, and the oil has deteriorated. Fill the vacuum pump cavity with vacuum pump oil. Observe whether the oil has emulsified (white foam) or carbonized (blackened). The deterioration of the vacuum pump oil will affect the friction between the rotating blades and the rotor, and cause the blades to get stuck in the pump cavity.   (6) The vacuum pump or motor is stuck.   (7) The oil pump is worn out or foreign matter accumulates.   (8) The suction pipe is blocked.    2. The vacuum pump cannot be started and the maintenance solutions are as follows:   (1) Provide the correct voltage for the motor.    (2) Compare the setting data of the motor starter overload protection with the data on the motor nameplate, and correct it if necessary. If the ambient temperature is high: the set value can be increased by 5% based on the normal motor current.   (3) Check the fuse.    (4) Repair or replace the motor. (Professional technicians are required to operate)   (5) Replace the vacuum pump oil, disassemble the vacuum pump, and repair the cylinder block and other parts. If the blades are severely damaged, the vacuum pump blades need to be replaced.   (6) Make sure that the motor is turned off, and then disconnect the fan cover. Rotate the motor and vacuum pump by hand. If the hand plate does not move, please remove the motor from the pump and check the vacuum pump and motor separately. If the vacuum pump is stuck, it needs to be repaired (repair and inspection by professional technicians).   (7) Replace the worn parts of the oil pump, clean the foreign matter inside and outside the vacuum pump, and repair the pump (maintenance and inspection by professional technicians are required).   (8) Remove the suction pipe, operate the pump alone, touch the air inlet and outlet with your hands to see if the pump can work normally. If the pump cannot pump air at this time, it means there is a problem with the pump itself.    If the vacuum pump fails to start normally, find the cause or location of the fault. The inner cavity of the pump should also be disassembled in time for cleaning and inspection to prevent secondary damage to the pump outlet. If you don't know much about the inside of the vacuum pump, you need to find a professional vacuum pump maintenance manufacturer to perform professional vacuum pump maintenance.
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The fault diagnosis of the rotary vane vacuum pump and the maintenance of the vacuum pump


Rotary vane vacuum pump fault judgment and vacuum pump maintenance: There are many common failure types of rotary vane vacuum pumps, and the failures can be divided into operation failures and performance failures. Once a failure occurs, it is necessary to analyze the cause of the failure, and perform proper vacuum pump maintenance according to the problem and cause of the failure.

  The common faults of the rotary vane vacuum pump are as follows:

   1. The pump does not rotate. If the situation is unknown, do not start the pump first to avoid aggravating the fault.

   2. The pump temperature is too high. Indicates that the oil temperature measured near the low exhaust valve exceeds the value in the user manual. As the temperature of the pump rises, the viscosity of the pump oil will decrease significantly, and the saturated vapor pressure of the pump oil will increase, which will increase the pressure of the pump and reduce the pumping efficiency; make rubber parts prone to aging; thermal expansion will decrease The working clearance, especially the thickness direction of some non-metallic rotating blades and the clearance of the inner hole of the copper sleeve will affect the reliability of the pump. The reason for the high pump temperature may be that the pump temperature is too high, the intake air temperature is too high, the intake air cooling device is faulty, the inlet pressure of the pump is too high and it cannot be operated continuously for a long time; the cooling water volume of the water-cooled pump is insufficient, and the circulating water design effect is not good; Temperature control water volume control valve failure, etc.

   3. Oil leakage. It may occur in shaft seals, sealing surfaces of fuel tanks and pump parts, drain plugs, oil traces, oil hole partitions, through-hole connections between stator parts and supports, and gas ballast valves. It may be caused by seal aging, improper installation, damage and malfunction, uneven surface, impurities, roughness and loose casting. If the oil returns after the pump is stopped, the oil will enter the gas ballast valve, and if the gas ballast valve is not closed, the oil may leak. When making homemade rubber gaskets, use oil-resistant rubber. It should follow the original design shape. If the sealing surface is too large, if it is not pressed tightly, the sealing surface will leak.

   4. The high power exceeds the standard. This may be caused by long-term continuous operation, such as excessive intake pressure, excessive exhaust pressure, sticking caused by debris, excessive pump temperature, too small matching gap (such as rotating blades), excessive voltage, and pump Excessive liquid returns to the pump. Otherwise it will damage the motor, try to avoid long-term continuous operation when the power is too high. If there are deposits on the surface, they need to be removed regularly.

  Rotary vane vacuum pump repair method:

   1. Before performing vacuum pump maintenance, prepare inspection methods.

  2, judge the fault and diagnose the fault. Judgment is accurate and saves trouble. The diagnosis needs to be verified.

  3. To troubleshoot, first simplify and then complicated, and first easy and then difficult. Do not dismantle those that do not need to be dismantled. Vacuum pump unit to reduce new damage caused by lack of special tools and improper operation. Generally speaking, the spliced ​​rotor is not removable, otherwise the shape and position tolerance will not be guaranteed and the rotor will be scrapped.

  4. For toxic, harmful and corrosive pumps, users should be asked to clean them first and inform the necessary protective measures to protect the health of maintenance personnel.


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