How to judge whether the magnetic levitation blower needs maintenance?

Judging whether the magnetic suspension blower needs maintenance can start from the following aspects:

I. Abnormal operating parameters

Abnormal pressure

Insufficient outlet pressure: If the outlet pressure of the magnetic levitation blower is obviously lower than the normal set value, there may be an internal problem. This may be due to the wear of impeller, which leads to the decrease of gas transmission capacity. For example, under normal working conditions, the outlet pressure of the blower should be stable at about 0.5MPa, and it needs to be checked when the pressure continues to drop below 0.3MPa.

Excessive pressure fluctuation: During normal operation, the pressure should fluctuate within a relatively stable range. If the pressure fluctuates greatly, it may be that the intake pipe is blocked or the control system is faulty. For example, the pressure fluctuates from 0.4MPa to 0.6MPa in a short time, which is an abnormal situation.

Abnormal flow

Flow reduction: When the actual flow of magnetic levitation blower is found to be lower than the rated flow, it may be caused by the blockage of air inlet, dirty filter or damaged impeller. For example, a blower with a rated flow rate of 100 m/h needs further inspection if the actual flow rate is continuously lower than 80 m/h.

Unstable flow rate: the flow rate fluctuates frequently, which may be due to pipeline leakage, valve failure or problems with the adjustment function of the control system. In this case, it will affect the stability of the whole system.

temperature anomaly

Motor temperature is too high: the motor has a certain temperature range during operation. If the motor temperature exceeds the rated temperature (generally, the allowable temperature is different for different insulation grades of motors, for example, the upper limit of the allowable temperature for class B insulated motors is about 130℃), it may be motor overload, poor heat dissipation or internal failure of the motor. It can be detected by touching the motor housing (pay attention to prevent burns) or using an infrared thermometer.

Abnormal bearing temperature: the normal working temperature of magnetic bearing also has a certain range. If the temperature is too high, it may be a failure of the cooling system of the bearing or a problem of the bearing itself, such as an unstable magnetic levitation force leading to an increase in friction.

Abnormal speed

Unstable rotating speed: The rotating speed of the magnetic levitation blower should run stably according to the set value. If the rotational speed fluctuates, it may be the fault of frequency converter, motor or the feedback mechanism of control system. For example, if the set speed is 3000rpm and the speed fluctuates frequently between 2800 and 3200 rpm, it needs to be checked.

The rotational speed can't reach the set value: This may be caused by insufficient motor power, excessive load or failure of transmission parts.

Second, the abnormal sound and vibration

Abnormal sound

Friction sound: if you hear the sound of metal friction inside, it is likely that there is friction between the impeller and the shell, the bearing and the journal or other mechanical parts. This kind of friction may be caused by worn parts, improper installation or foreign objects entering.

Impact sound: obvious impact sound is heard, which may be that the impeller is loose, parts fall off or large foreign objects enter the blower. For example, when small parts such as screws fall into the blower, it will produce intermittent impact sound.

Vibration anomaly

Increased vibration amplitude: The vibration amplitude of the normal magnetic suspension blower is very small. When the vibration amplitude increases obviously, it may be caused by imbalance of impeller, damage of bearing or loose foundation. A vibration sensor or a portable vibrometer can be used to detect the vibration amplitude. Generally speaking, when the effective value of vibration speed exceeds 7.1mm/s (the specific value can be adjusted according to equipment standards), it is necessary to investigate the cause of vibration.

Abnormal vibration frequency: if the vibration frequency changes abnormally, it may be due to the failure of the rotating parts of the motor, such as unbalanced rotor or misaligned coupling.

Third, the appearance and environment

Leakage phenomenon

Gas leakage: check whether there is gas leakage in the pipeline joints, flanges, seals and other parts. Soap water can be applied to the parts that may leak. If bubbles are generated, it means there is a leak. Gas leakage will not only reduce the efficiency of the system, but also have potential safety hazards.

Oil leakage (if there is a lubricating oil system): observe whether there is oil stain around the equipment. Oil leakage may be caused by seal damage or tubing rupture, which will affect the normal operation of lubrication system and may damage other components.

Appearance damage

Damage to the casing: check the casing of the blower for cracks, deformation or corrosion. Damage to the casing may affect the structural strength and tightness of the equipment. For example, cracks appear after the shell is hit by a heavy object, which may expose the internal components and increase the risk of failure.

Loose or falling parts: check whether the connecting parts (such as bolts and nuts) are loose and whether small parts (such as nameplates and sensor housings) fall off. Loose parts may lead to unstable operation of the equipment, and falling parts may fall into the equipment and cause damage.

Fourth, the electrical system

Control cabinet fault prompt

When the fault indicator light on the control cabinet lights up, it indicates that there is something wrong with the equipment. Different fault indicators represent different fault types. For example, when the overload protection indicator is on, it may be that the motor is overloaded. The temperature alarm indicator is on, which may be that the temperature of the motor or other key components is too high.

Abnormal electrical parameters

Measure parameters such as current and voltage of the motor. If the current is too large, the motor may be overloaded or short-circuited; The abnormal voltage may be a power supply system fault or a frequency converter fault. For example, the rated current of the motor is 10A. When the running current continuously exceeds 12A, it is necessary to check the load and electrical system of the motor.