Fault Symptom: Filter Blockage
A blocked air filter leads to increased energy consumption and wasted electricity, with dust possibly penetrating the filter and entering the compressor, affecting the lifespan of the compressor oil and potentially clogging the oil separator.
Fault Handling
- The filter element, made of special materials, is the core component of the filter and needs special maintenance as it is a wear-and-tear part.
- After long periods of operation, the filter element will accumulate impurities, leading to increased pressure and reduced flow, necessitating timely cleaning.
- During cleaning, ensure not to deform or damage the filter element.
High-quality filters usually use ultra-fine fiber paper filled with synthetic resin, effectively filtering impurities and having strong contaminant-holding capacity. The equipment requires high-strength filter paper to withstand strong airflows, ensuring filtration efficiency and extending the equipment’s lifespan.
The filter paper has a pore size of about 10 microns. The surface dust should be removed every 1000 hours using low-pressure air blown from the inside out. The air filter is equipped with a differential pressure indicator. When the display panel indicates a blockage, it means the air filter needs cleaning or replacement.
II. Oil Filter
The oil filter, usually made of paper, removes impurities such as metal particles and oil degradation products from the oil, with a filtration precision between 5 microns and 10 microns, protecting the bearings and rotors.
Fault Symptom: Oil Filter Failure
Fault Handling
Whether to replace the oil filter can be determined by its differential pressure indicator. If the indicator light is on, it means the oil filter is blocked and must be replaced. A new machine needs its oil and oil filter replaced after the first 500 hours of operation, and thereafter when the differential pressure indicator lights up. Failure to replace a blocked oil filter can lead to insufficient oil supply, high exhaust temperatures, and shortened bearing life.
The effective lifespan of the oil filter is determined by:
- Amount of impurities: The lifespan ends when the filter's capacity to absorb impurities is reached.
- Machine temperature and filter paper's anti-carbonization ability: High temperatures shorten the oil filter’s lifespan, accelerating filter paper carbonization.
High-quality oil filters typically last about 2000 to 2500 hours. In frequency conversion screw machines used at low frequencies for long periods, lower temperatures lead to more water in the oil separator, requiring high water-resistance filter paper. Low-frequency usage means lower system pressure, so oil filters need to have low resistance and good permeability.
The filtration precision and effect depend on the adsorption capacity of the filter paper. Fiber filter paper offers good filtration but is costly and rarely used due to low sales volume.
III. Oil Separator Element
The oil separator element, made of multi-layered fine glass fiber, can almost completely filter out misty oil from the compressed air. Under normal operation, the oil separator element can be used for about 3000 hours.
Fault Symptom: Blockage/Broken/Burned/Low Separation Efficiency
Fault Handling
The lifespan of the oil separator element is greatly affected by the quality of the lubricating oil and the surrounding environment. In highly polluted environments, pre-filters can be installed.
- Blockage: A blocked oil separator element increases the compressor motor's current. Excessive pressure can deform the element, potentially causing the main engine to seize. Generally, screw air compressors have a pressure gauge before the element. When the pressure difference between the pre-filter and the supply pressure gauge reaches 0.08 MPa, the oil separator element should be replaced.
- Broken: A broken oil separator element results in significant oil consumption, with large amounts of oil in the air tank and pipelines. Causes include not replacing the element timely, using poor-quality elements, or improper installation.
- Burned: Though rare, burned oil separator elements can be caused by poor oil quality, inferior element quality, or improper installation.
- Low Separation Efficiency: High oil content in the compressed air damages subsequent equipment and user equipment. Causes include poor quality of the element or improper installation.
IV. Lubricating Oil
Air compressor oil forms a protective film between two friction screws, preventing contact and providing lubrication, reducing wear, and offering cooling, noise reduction, sealing, and rust prevention functions.
Fault Symptom: Lubricating Oil Failure
Fault Handling
New compressors require an oil change after 500 hours of operation, and every 4000 hours thereafter. However, various factors affect the oil's performance, so the replacement cycle should be determined based on the actual operating environment.
Factors affecting the replacement cycle include:
- Oil Quality: Qualified oil from reputable manufacturers can last 4000 hours under standard conditions, while inferior oil requires more frequent changes.
- Air Humidity: High humidity leads to more water entering the compressor, degrading the oil and shortening its lifespan.
- Impurities: Air and internal impurities contaminate the oil, causing it to fail.
- Acidic or Alkaline Gases: Environments with high levels of such gases affect the oil’s performance and reduce its lifespan.
V. Belt
Belts have good elasticity, absorbing shocks and vibrations, and operate smoothly without noise. In case of overload, the belt slips on the pulley, protecting other components.
Fault Symptom: Poor Belt Elasticity
Fault Handling
After shutting down the compressor and ensuring it has cooled and is depressurized, inspect the transmission belt. If the belt is not deformed, adjust the bolts to the appropriate tension. If damaged beyond repair, replace it.
Ensure the belt tension is consistent to prevent slipping. After replacement or adjustment, run for about 30 hours and monitor for changes. Proper handling prevents excessive load and protects the motor and other parts. Fix the machine head securely and operate carefully to avoid mistakes that could cause damage.
VI. Solenoid Valve
Fault Symptom: Not Operating
Fault Handling
Solenoid valve faults affect the operation of switching and regulating valves. Common causes and solutions for non-operating solenoid valves include:
- Loose or Fallen Wires: Tighten the connections to resolve the issue.
- Burnt Coil: Remove the solenoid valve wiring and use a multimeter to check. If open, the coil is burnt, possibly due to moisture causing a magnetic leak, leading to excessive current. For emergency handling, switch the manual button from "0" to "1" to open the valve.
- Valve Stuck: Small gaps between the solenoid valve slider and valve core can cause sticking if mechanical impurities enter or lubrication is insufficient. Use a wire to push the valve back. For a thorough fix, disassemble the solenoid valve, clean, and reassemble, ensuring correct part order and wiring.
- Air Leakage: Leakage causes insufficient air pressure, making valve operation difficult, due to damaged seals or worn sliders. Check for solenoid valve faults under a power-off state, replace damaged coils, or repair valve body leaks.
Using these methods, screw air compressor solenoid valve faults can be effectively resolved, ensuring normal equipment operation.