Air compressor at high temperature

The impact of excessive ambient temperature on the temperature of screw air compressors is mainly manifested in two aspects:
mechanical failure
1. The higher the temperature, the thinner the air, the lower the working efficiency of the air compressor, and the more time the air compressor is under load, resulting in more heat generated by the air compressor, leading to high temperatures.
2. Generally, when designing an air compressor, there is a design operating ambient temperature (30-40 ℃). Under the design operating ambient temperature, the maximum temperature of the air compressor is generally close to the protection temperature of the air compressor. If the ambient temperature of the air compressor is higher than the design operating ambient temperature, it will increase the temperature of the air compressor, causing the air compressor to exceed or even exceed the shutdown temperature of the air compressor, resulting in high temperature of the air compressor.
1. Oil stop valve fault
The abnormal operation of the oil stop valve (also known as the oil cutoff valve) can cause the main engine to rapidly heat up due to lack of oil, and in severe cases, it can cause the screw assembly to burn out.
2. Compressor oil filter failure
First, it affects the supply of compressor oil, resulting in equipment lubrication failure and high temperature; Second, it hinders the normal circulation of compressor oil, affects the heat dissipation of the compressor, and causes high temperatures.
3. Thermal control valve (temperature control valve) fails to work
The thermal control valve is installed in front of the oil cooler and its function is to maintain the exhaust temperature of the machine head above the pressure dew point. If the thermal control valve fails, the lubricating oil may enter the machine head directly without passing through the cooler, causing the oil temperature to fail to drop, causing overheating.
4. Abnormal oil volume regulator of compressor
The function of the fuel quantity regulator is to control the amount of oil injected into the compressor. If the amount of oil injected is too small, the compressor will experience high temperatures. At this time, the amount of oil injected should be appropriately increased. However, it should be noted that the oil volume regulator has been calibrated before the equipment leaves the factory, so it is not recommended that the user privately adjust it. Instead, it should be negotiated with the equipment manufacturer or adjusted by professional maintenance personnel.
5. Abnormal compressor oil cooler
This fault is common in water cooled air compressors. Check the temperature difference between the inlet and outlet of the cooler. If the temperature difference is less than 5 ℃, the heat exchange effect of the cooler will be greatly reduced. The cause of this failure is mostly due to clogging or scaling of the cooler. At this time, just remove the cooler and clean it. For air-cooled air compressors, more attention needs to be paid to whether the ambient temperature is too high and whether the cooling fan operates abnormally.
6. Air compressor head failure
Abnormal wear of the air compressor head causes increased heat production and high temperatures. There are two common reasons for this failure: one is poor lubrication of the air compressor oil, and the other is due to the head itself. The solution is to replace the qualified air compressor oil or replace the air compressor head.
7. Air filter failure
The air filter is clogged and the gas production is too small, causing an increase in the load on the air compressor, causing the air compressor to be in a long-term loading state, increasing heat production, and causing high temperatures. The air filter needs to be replaced at this time.
8. Oil gas separator fault
Blockage of the oil gas separator causes excessive internal pressure in the air compressor, resulting in high temperatures. There are two reasons for this failure: first, there are problems with the quality or service life of the oil water separator itself; The second reason is that the quality of air compressor oil is not up to standard, resulting in poor separation ability from air. At this time, the oil gas separator or air compressor oil should be replaced.
9. Temperature sensor and computer malfunction, abnormal reading.
Effect of air compressor oil
1. Insufficient oil quantity of air compressor
During the operation of the air compressor, if the oil level of the air compressor oil is lower than the low oil level mark L or MIX, the air compressor oil level is insufficient. The air compressor has insufficient oil, which leads to poor heat dissipation, resulting in high temperature of the compressor. At this time, it should be stopped immediately for refueling.
2. Air compressor oil deteriorated
Due to quality problems or oxidation deterioration of compressor oil beyond the service life, the fluidity of the oil becomes poor, and the heat exchange capacity decreases, resulting in the heat of the air compressor head not being completely and timely taken away. At this time, it is necessary to immediately stop and change the oil.
3. Improper selection of air compressor oil viscosity
The viscosity of the air compressor oil is too low and the lubrication is poor, resulting in abnormal wear of the equipment and excessive heat generation; Excessive viscosity and poor oil fluidity prevent heat from being emitted in a timely manner, which can cause high temperatures in the air compressor. Therefore, when maintaining the compressor, the user needs to refer to the compressor's service manual and the user's actual operating conditions to select an appropriate viscosity level.
4. The quality of air compressor oil is not up to standard
The main points are as follows: a. The thermal oxidation performance of air compressor oil is poor, resulting in sludge, paint film, and other deposits during use, affecting the fluidity of the oil, while reducing the lubricating performance of the oil; B. The viscosity temperature performance of air compressor oil is poor, low temperature fluidity is insufficient, and high temperature lubricity is poor; The air separation ability of air compressor oil is poor, affecting oil gas separation, etc.
The above is the cause analysis of common high temperature faults of screw air compressors. So for users, how to avoid or timely detect compressor failures, thereby reducing production accidents and cost losses?
Environmental and equipment factors
1. Layout of air compression station
When installing an air compressor station, it is necessary to predesign the location of common equipment such as air compressors, air storage tanks, desiccants, filters, etc., and reserve sufficient heat dissipation space and maintenance space between equipment and equipment, as well as between equipment and walls. The air compression station should maintain good ventilation, and install exhaust fans if necessary. If the air compressor station is built outdoors, it is necessary to do a good job of dustproof, waterproof, antifreeze, and explosion-proof treatment to avoid abnormal damage to the air compressor caused by dust, moisture, extreme high and low temperatures, etc. In addition, it is best to reserve an area for air compressor maintenance in the air compression station, which is based on the area required for the largest air compressor maintenance in the air compression station, to ensure timely and convenient maintenance in case of air compressor failure.
2. Regular maintenance
Develop a good habit of regular inspection and maintenance, and form maintenance and repair records. The inspection scope includes the leakage of compressed air and air compressor grease, regular replacement of lubricating grease and other vulnerable parts as required, regular testing of the voltage and current of the air compressor station, and proper surface cleaning and environmental cleaning of the air compressor and other equipment. For detailed inspection and maintenance, please refer to the equipment maintenance manual.
Choose the right accessory
This includes common vulnerable parts such as air filters and oil water separators, as well as air compressor oil required for lubrication. Regarding the selection of air compressor oil, the following suggestions are given:
1. Choose a suitable viscosity and choose a compressor oil with good viscosity-temperature performance
The viscosity of compressor oil is selected based on the consideration of both lubricity and fluidity. If there are no special conditions for the working condition of the air compressor, the user can refer to the equipment manual for selection; If the working condition of the air compressor is relatively special, it needs to be adjusted appropriately according to the actual working condition. For example, if the operating temperature of an air compression station is high, it is necessary to consider the impact of temperature on viscosity, and appropriately increase viscosity; If the air compressor station is located outdoors and the temperature difference between day and night is relatively large, it is necessary to choose an air compressor oil with better viscosity and temperature performance.
2. Select compressor oil with good thermal oxidation stability
For air compressors, due to compressed gas, a 20% oxygen content is a significant test of the antioxidant performance of compressor oil. Thermal oxidation stability can not only extend the service life of compressor oil, but also reduce the deposition and accumulation of sludge, paint film, and other substances caused by high-temperature oxidation. These are very important factors that cause high temperature in the compressor and affect the normal operation of the compressor. In addition, the acidic substances produced by oxidation also have a negative impact on the metal components in the compressor to a certain extent.
3. Select compressor oil with good air separation performance
The control of air release and foam will affect the lubricity of the compressor, the effect of oil-gas separation of the compressor and the service life of the oil-gas separator to a certain extent. In addition, if the oil gas separation effect is not good, it can also cause excessive oil content in the compressed air, affecting subsequent production and product quality.
4. Consider the water resistance of compressor oil
Especially in coastal areas, outdoor air compression stations, and other situations where the air humidity is high, the moisture content in the air is high, and the presence of condensed water can easily cause the emulsification of compressor oil, thereby affecting the performance of compressor oil. Therefore, it is necessary to select a compressor oil with good water resistance.
5. Do a good job of oil detection and tracking
If conditions permit, regular oil testing is necessary for users. By regularly sampling and detecting the performance changes of compressor oil, potential problems and faults of the compressor can be detected in a timely manner through performance changes, and more accurate oil change guidance can be provided to users to avoid oil waste