Chapter 4 Mechanical Fault Analysis and Repair-KIMAIR.-The source of power for air compressors

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Section 1 Bearing Damage Repair

Bearings are critical components in air compressors, primarily serving to support the rotating shaft and reduce friction. Bearing damage can lead to unstable operation of the compressor or even shutdown. The following are some common causes of bearing damage and repair methods: 1. Causes of Bearing Damage ▪ Insufficient lubrication: Poor lubrication is one of the most common causes of bearing damage. Insufficient or poor-quality lubricants can lead to overheating and wear of the bearing. ▪ Contamination: Dust, metal debris, and other impurities entering the bearing can accelerate wear. ▪ Overload: Prolonged operation under overload conditions can subject the bearing to excessive pressure, leading to fatigue damage. ▪ Improper installation: Improper bearing installation, such as misalignment or uneven tightening, can cause uneven force on the bearing, accelerating damage. ▪ Environmental factors: Harsh environments, such as high temperatures and humidity, can accelerate corrosion and aging of the bearing. 2. Diagnosis of Bearing Damage ▪ Auscultation method: Using a stethoscope or screwdriver, listen closely to the bearing area for any abnormal sounds, such as clicking or whistling. ▪ Temperature detection: Use an infrared thermometer to check the bearing temperature. Abnormally high temperatures may indicate bearing damage. ▪ Vibration detection: Use a vibration detector to monitor the bearing's vibration. Abnormal vibrations suggest that the bearing may have an issue. ▪ Visual inspection: After removing the bearing, carefully inspect the inner and outer rings, rolling elements, and cage for cracks, wear, or corrosion. 3.Bearing Damage Repair ▪ Replace the bearing: If the bearing is severely damaged and cannot be repaired, replace it with a new one. Select a high-quality bearing that matches the original model to ensure consistent size and performance. ▪ Clean and lubricate: For lightly damaged bearings, clean and re-lubricate them. Use a special cleaner to thoroughly clean the bearing, removing any impurities, and then apply a suitable amount of high-quality grease. ▪ Adjust and align: Ensure that the bearing is installed correctly, properly aligned, and tightened evenly. Use special tools for adjustment and alignment to avoid uneven force on the bearing. ▪ Environmental improvement: Improve the compressor's working environment by avoiding harsh conditions such as high temperatures and humidity, thereby extending the bearing's service life.

Section 2 Belt Slipping and Replacement

The belt is a crucial component of the air compressor's drive system, responsible for transmitting the motor's rotational power to the compressor. Belt slipping can reduce compressor efficiency and even cause downtime. Here are some common causes of belt slipping and methods of handling it: 1. Causes of Belt Slipping ▪ Insufficient belt tension: Insufficient belt tension is one of the most common causes of belt slipping. Low tension leads to poor contact between the belt and pulley, resulting in slippage. ▪ Belt aging: Over time, the belt may age, causing a loss of elasticity and increasing the likelihood of slipping. ▪ Pulley wear: Wear or unevenness on the pulley surface can cause poor contact between the belt and the pulley, leading to slippage. ▪ Poor lubrication: Oil or dirt on the belt or pulley surface can reduce friction, causing slippage. ▪ Excessive load: If the compressor's load exceeds the belt's capacity, it can also cause slipping. 2. Diagnosis of Belt Slipping ▪ Auscultation method: Listen for any abnormal squealing or friction noises, which may be signs of belt slipping. ▪ Visual inspection: Check the belt for visible signs of wear, cracks, or deformation, and examine the pulley surface for smoothness. ▪ Tension testing: Use a tension meter to measure the belt's tension and ensure it is within the normal range. ▪ Load testing: Check the compressor's load conditions to ensure they are within the normal range. 3. Treatment of Belt Slipping ▪ Adjust tension: Use a tensioner or adjustment bolts to adjust the belt tension and ensure it is within the normal range. Apply even force during adjustment to avoid making it too tight or too loose. ▪ Clean and lubricate: Clean the surfaces of the belt and pulley, removing oil and dirt. Avoid applying lubricant to the belt surface, as this could reduce friction. ▪ Replace the belt: If the belt is severely aged or shows visible damage, replace it with a new one. Choose a high-quality belt that matches the original model to ensure consistent size and performance. ▪ Inspect the pulley: Check the surface of the pulley for wear or unevenness. If necessary, repair or replace it. ▪ Adjust the load: Ensure the compressor's load is within the normal range to avoid overload operation.

Section 3 Compressor Air Leak Handling

Compressor air leaks are a common mechanical fault that can reduce compressor efficiency and increase energy consumption. Here are some common causes of air leaks and methods for handling them: 1.Causes of Air Leaks ▪ Damaged seals: Seals such as O-rings or gasket seals may fail, leading to gas leaks. ▪ Loose pipe connections: Loose or poorly sealed pipe connections can result in gas leaks. ▪ Worn cylinders: Internal wear or damage to the cylinder can lead to gas leaks. ▪ Valve failure: Failure of intake or exhaust valves can cause gas leaks. ▪ Environmental factors: Harsh conditions such as high temperatures and humidity can accelerate seal aging and damage. 2.Diagnosis of Air Leaks ▪ Auscultation method: Listen for any abnormal airflow sounds, which may indicate an air leak. ▪ Pressure detection: Use a pressure gauge to check the compressor's output pressure. If the pressure drops, it could be a sign of an air leak. ▪ Visual inspection: Inspect the connection points of the compressor components for any visible bubbles or gas leaks. ▪ Soap water test: While the compressor is running, apply soap water to possible leak areas and observe for bubble formation. 3.Handling Air Leaks ▪ Replace seals: If seals are damaged, replace them with new ones. Choose high-quality seals that match the original type to ensure consistent size and performance. ▪ Tighten connections: Check the fasteners at pipe connections and ensure they are tightly secured, with no looseness. Repair the cylinder: If the cylinder is worn or damaged, it should be repaired or replaced. Use specialized tools to ensure the interior of the cylinder is smooth during repairs.