Atlas Copco Fixed Screw Air Compressor Failure and Elimination Methods

There are many types of air compressors, which can be categorized into volumetric compressors, reciprocating compressors  and centrifugal compressors according to their working principles. Commonly used air compressors are piston air compressor, screw air compressor, centrifugal air compressor and sliding vane air compressor. With the rapid development of aviation field, the combination of screw air compressor and aviation industry development is becoming closer and closer. As a transmission medium, Fixed Screw Air Compressor has the following advantages:

First, compressed air can be transmitted over long distances with low pressure loss.

Secondly, compressed air effectively avoids dangerous accidents such as explosion or fire.

Thirdly, compressed air is cleaner.

1. Composition of Atlas Copco Fixed Screw Air Compressor

Atlas Copco oil-injected screw air compressor consists of air end system, air intake system, exhaust system, oil injection and oil-air separation system, cooling system, control system and electrical system, etc. Some models are also equipped with built-in refrigerated dryer.

2. Working principle of screw compressor

The air enters the compressor head through the air filter and the open air inlet valve, at this time the air is compressed. The mixture of compressed air and lubricating oil flows into the oil-air separator through the check valve, then the lubricating oil is separated from the compressed air, and the compressed air is discharged through the minimum pressure valve, air cooler and outlet valve.

3. Common faults and analysis of screw air compressor

In the daily use of air compressors, there are often a variety of faults, the following we will analyze the common faults of air compressors and their causes.

3.1 Overload alarm stopping of air compressor motor

The red alarm light is on during the operation of the air compressor, and the motor icon flashes on the display. First of all, use the handheld infrared thermometer to measure the surface temperature of the motor, if the temperature is within the normal temperature range of the motor, it can be ruled out that the alarm is caused by the motor over-temperature; then use a multimeter to measure the inlet voltage of the air compressor, if the value is more than the nominal voltage of 380V, in order to protect the unit air compressor, you need to carry out a shutdown check; after checking the fault found to be caused by the high voltage of the system,  when the system voltage is restored, start the air compressor again.

3.2 Air compressor automatic shutdown

Check the operation panel, if you find that there is no history of fault records, and start the air compressor again, the machine can also start normally, but there will still be automatic shutdown fault. Next, first of all, check the distribution box of the air compressor, if you find that the voltage, current and temperature of the air terminal are normal; then check the overload relay, line contactor, star contactor and delta contactor of the air compressor electrical system, analyze whether the voltage and current are normal; finally, check the auxiliary contactor, if it is not securely absorbed by the K21 line contactor, remove and replace the K21 line contactor and then start the air compressor.

3.3 Low dew point value of cold dryer causes automatic shutdown of cold dryer and alarm of air compressor

First of all, check the control panel of the air compressor, if the display has no system icon flashing, then test the inlet line of the air compressor, observe whether the voltage and current is normal; then check the air compressor, if the loading and unloading are normal, and then observe the dew point value of the cold dryer. When the dew point value decreases to below 0℃, the cold dryer will stop automatically, and the alarm light on the display will be on. The treatment method is to disconnect the power supply line of the cold dryer when the ambient temperature is lower than 5℃ during the operation of the air compressor.

3.4 High exhaust temperature of the air compressor

The exhaust temperature of the Atlas air compressor headstock can be read from the operation panel display. The shutdown standard for the outlet temperature of the Atlas air compressor head is 111°C. When the outlet temperature of the air end exceeds 111°C, the air compressor shuts down and alarms.

The process of compressed air is as follows: when the air enters the compressor head through the air filter and the open inlet valve, the compressed air is compressed at this time; the mixture of compressed air and lubricant flows into the oil-air separator through the check valve to separate the lubricant from the compressed air; and the compressed air is then discharged from the minimum pressure valve, air cooler and outlet valve.

According to the process of compressed air it can be analyzed that the causes of air compressor exhaust temperature is too high for the following reasons: first, the lubricant oil is lower than the green area of the oil lens; second, the lubricant oil deterioration emulsification; third, the oil-air separator filter element is too dirty; fourth, the oil valve malfunction; fifth, radiator clogging; sixth, the oil filter is too dirty; seventh, the temperature control valve damage occurs.

For such problems, first check the air compressor lubricant level, if the oil level is normal; check whether the lubricant oil of the air compressor is deteriorated emulsification; if not, then check the radiator of the air compressor, if there is a layer of dirt on the surface of the radiator, use compressed air to blow the radiator surface of the dirt clean, and then start the compressor, the high-temperature alarm disappeared, and the compressor is running normally.

4. Conclusion

With the development and progress of industry, socialized large-scale production has led to an increase in the proportion of state-owned assets in machinery and equipment. As the main body of the air source device, the air compressor has a wider application range. Among them, the screw air compressor has been widely used due to its high reliability, convenient operation and maintenance, and good dynamic balance. Atlas Copco Fixed Screw Air Compressor are frequently used in  aviation industry. Due to frequent use, various faults inevitably occur in air compressors, and once a fault occurs in an air compressor, it will have a great impact on normal work. Under the premise of understanding the structure of air compressor and its principle, our company summarizes the air compressor faults we encountered and discusses how to deal with these faults. Click here.