Compared with the traditional piston air compressor, the screw air compressor has the characteristics of stable operation and low noise. However, many screw compressor users will encounter abnormal noises when the equipment is running, such as metal collision, uniform knocking, friction howling, etc. How is this going?
1. The reason for the abnormal sound: the belt is too loose, and the grooves of the main and passive belts are too large, resulting in slippage and noise.
Empty belt slippage can be judged and determined from the following aspects:
When you get close to the equipment, you can smell the burnt belt. Observe carefully, there will be belt debris on the ground near the belt;
There is abnormal friction sound between the pulley and the belt;
Due to the uneven load, the current swing is large.
Solution: Rotate the adjusting bolt to adjust the belt to proper tightness, the deformation is less than 5mm, but not too tight. After readjustment, run with load, if it still slips, you need to replace the belt.
The replacement of the belt is basically the same as the adjustment procedure of the belt, but it should be noted that the force should be moderate, otherwise the tension of the new belt will be damaged due to the difference of the belt. At the same time, be careful not to splash lubricating oil on the belt or pulleys to prevent the belt from slipping.
2. The reason for the abnormal sound: the screw air compressor is short of oil when it is running, so that the male and female screws directly engage without lubricating oil, and the metal dry friction produces roaring sound.
In the oil-injected screw compressor, the male rotor directly drives the female rotor to rotate, but there is no direct contact between the two. The oil film is created by the lubricating oil sprayed into the machine head and acts as a barrier. Therefore, lubricating oil is very important for screw compressors. If there are failures such as "lack of oil" in the screw compressor, direct contact with the screw rotor, abnormal noise, and bearing damage.
However, the "lack of oil" in the machine head is not necessarily caused by insufficient total amount of lubricating oil, but may also be caused by local lack of oil, low pressure of lubricating oil, etc. Direct causes such as: oil failure, oil cooler, oil pipe blockage, loose oil pipe joints and oil leakage; indirect faults may include: minimum pressure valve failure, unqualified compressor lubricating oil, irregular design of oil and gas separation tank, oil return check valve damage , Improper installation of the oil return pipe, large gas consumption, overloaded and low-pressure use (or the oil treatment capacity of the machine before leaving the factory is too tightly matched with the exhaust volume of the machine), etc.
Solution: Check the oil level, replace the oil filter, deal with the faulty parts, and adjust the system configuration.
3. The reason for the abnormal sound: the intake valve is not closed tightly, the air leakage is large, and the intake valve anti-vibration.
Lifting check valves cause noise. A check valve is generally installed at the outlet of the compressor to prevent the high-pressure gas backflow system from stopping the compressor.
Solution: Replace or adjust the faulty valve. When inspecting, repairing and assembling various parts of the air valve, the following points should be paid attention to:
The intake valve parts of the screw compressor should be clean;
The contact between the valve plate and the valve seat, the radial clearance between the valve plate and the lift limiter, the lift-off amount of the valve plate, and the spring specifications all meet the design requirements;
When replacing internal components (such as valve plates, buffer plates, springs, etc.), they must be replaced at the same time;
Leak test: Leak test should be carried out before installation of the gas valve.
4. Cause of abnormal sound: motor bearing failure
solution:
When the motor is running, use a screwdriver with the tip close to the bearing cover and the ear close to the wooden handle of the screwdriver to monitor the sound of the bearing. If there is a faint rolling sound on the inner and outer rings of the rolling body, the sound is monotonous and even, making people feel relaxed, indicating that the bearing is in good condition and the motor is operating normally. If abnormal sound is heard, analyze the cause and deal with it;
If you hear obvious rolling and vibrating sounds of rolling elements, it means that the bearing clearance is too large or the wear is serious, and it needs to be replaced;
The sound of the rolling elements is hoarse and the tone is heavy, indicating that the lubricating oil of the bearing is too dirty and impurities have invaded. It is necessary to clean the bearing with kerosene and replace it with new lubricating oil;
The rolling elements have irregular impact sounds, indicating that some rolling elements of the bearing are broken and need to be replaced;
The whistling sound mixed with the rolling sound of the rolling elements indicates that the bearing lacks lubricating oil or the lubricating oil is improperly selected, and it is necessary to add clean lubricating oil or replace it with a suitable lubricating oil.
5. Cause of abnormal noise: host failure. The main engine enters foreign matter, causing the male and female screws to collide with each other and produce a roaring sound; the gap between the male and female screws and the end face of the bearing is too large; the bearing of the main engine is damaged.
Solution: Overhaul the host and re-adjust the clearance of the host. According to industry research data, the gap ratio of screw compressors is generally controlled between 0.8 and 1.2 wires.
When the screw compressor rotates at high speed, due to the thermal deformation of the tooth profile and the wear of the gear tooth surface, the gap between the running surfaces tends to decrease, and the gap between the non-tracking surfaces tends to increase. In order to ensure the long-term reliable operation of the compressor, the gap between the chasing surface and the non-chasing surface should be increased during maintenance, and the ratio of the chasing surface to the non-chasing surface gap should be 1.0 to 1. The two are more reasonable.
5. The reason for the abnormal sound: the noise reduction system is damaged. The noise reduction system of the screw compressor is mainly composed of chassis, bracket, frame, door panel, noise reduction cotton, sealing strip and other components.
Solution: Check whether the main body of the effect system is intact and whether the connecting bolts are loose. During the operation of the compressor, it will be affected by loads such as air force, inertia force, friction force, etc., which will stimulate the vibration of the compressor shell, the chassis of the whole machine, the piping system, the supporting structure and other components. If proper measures are not taken to limit these vibrations, abnormal noise will result.
The noise of screw air compressors has different manifestations and causes are also different. However, for high-speed operating equipment, abnormal noise indicates that a fault has occurred, and corresponding measures must be taken as soon as possible to investigate and solve it to ensure the safe production and operation of the compressor.
Screw compressor noise reasons and troubleshooting
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