Summer is coming, and the temperature of the air compressor is too high. Are 19 possible causes of malfunctions sufficient?

Summer is coming, and the temperature of the air compressor is too high. Are 19 possible causes of malfunctions sufficient?

The hot summer is approaching, and high temperature is one of the common faults in the use of air compressors, especially for mobile air compressors used for outdoor construction work. This article aims to address this issue by identifying various potential causes and analyzing them.

1. Excessive ambient temperature has the following two impacts on screw air compressors:

A: The higher the temperature, the thinner the air (just like air compressors have low efficiency in high-altitude areas), resulting in a decrease in the efficiency of the air compressor, causing it to be in a loaded state for more time, carrying more load, and generating more heat. As a result, the temperature of the air compressor will definitely be higher.

B: When designing an air compressor, there is usually a design operating environment temperature (30-40 degrees). The maximum temperature of the air compressor when operating at the design operating environment temperature 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 environment temperature, it will increase the temperature of the air compressor, causing it to even exceed the shutdown temperature of the air compressor, resulting in high temperature of the air compressor.

2. The air compressor system is short of oil

The oil level in the oil and gas tank can be checked. After the shutdown and pressure relief, when the lubricating oil is in a static state, the oil level should be slightly higher than the high oil level mark H (or MAX). During the operation of the equipment, the oil level should not be lower than the low oil level mark L (or MIX). If insufficient fuel is found or the oil level cannot be observed, the machine should be stopped immediately to refuel.

3. The oil stop valve (oil shut-off valve) is not working properly

The oil stop valve is usually a two position, normally closed solenoid valve that opens when starting and closes when stopping to prevent the oil in the oil and gas tank from continuing to spray into the machine head and out from the air inlet during shutdown. If the component is not turned on during loading, the host will quickly heat up due to lack of oil, and in severe cases, it may cause the screw assembly to burn out.

4. Oil filter issue

A: The blockage of the oil filter and the failure to open the bypass valve will cause the air compressor oil to not reach the machine head, and the main engine will quickly heat up due to lack of oil.

B: The blockage of the oil filter reduces the flow rate. One situation is that the air compressor does not take away the heat completely, and the temperature of the air compressor slowly rises, resulting in high temperature. Another situation is that the air compressor is at high temperature after unloading, because the internal oil pressure of the air compressor is high during loading, and the air compressor oil can pass through. However, after unloading, the low pressure of the air compressor oil makes it difficult for the air compressor oil to pass through the air compressor oil filter, and the flow rate is too small, resulting in high temperature of the air compressor.

5. Thermal control valve (temperature control valve) malfunction

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. Its working principle is that at the beginning of the machine, due to the low oil temperature, the thermal control valve branch is opened, the main circuit is closed, and the lubricating oil is directly sprayed into the machine head without passing through the cooler; When the temperature rises above 40 ℃, the thermal control valve gradually closes, and oil flows through both the cooler and the branch at the same time; When the temperature rises above 80 ℃, the valve is completely closed, and all lubricating oil enters the machine head through the cooler to cool the lubricating oil to a greater extent.

If the thermal control valve malfunctions, lubricating oil may enter the machine head directly without passing through the cooler, causing the oil temperature to fail to decrease and resulting in overheating. The main reason for its failure is that the elastic coefficient of the two thermal sensitive springs on the valve core changes after fatigue, and they cannot operate normally with temperature changes; Secondly, the valve body is worn, and the valve core is stuck or does not move properly, making it unable to close normally. It can be repaired or replaced according to the situation.

6. Check if the fuel regulator is functioning properly, and if necessary, increase the fuel injection amount appropriately

The fuel injection quantity has been adjusted before the equipment leaves the factory and should not be changed under normal circumstances.

7. Engine oil has exceeded its usage time and deteriorated

The fluidity of the engine oil deteriorates, and the heat exchange performance decreases. Causing the heat from the compressor head to not be completely dissipated, resulting in high temperatures in the compressor.

8. Check if the oil cooler is working properly

For water-cooled models, the temperature difference between the inlet and outlet water pipes can be checked. Normally, it should be between 5-8 ℃. If the temperature is below 5 ℃, scaling or blockage may occur, which will affect the heat transfer efficiency of the cooler and cause poor heat dissipation. In this case, the heat exchanger can be removed and cleaned.

9. Check if the inlet temperature of the cooling water is too high, if the water pressure and flow rate are normal. For air-cooled models, check if the ambient temperature is too high

The inlet temperature of cooling water should generally not exceed 35 ℃, the water pressure should be between 0.3-0.5MPA, and the flow rate should not be less than 90% of the specified flow rate. The ambient temperature should not exceed 40 ℃. If the above requirements cannot be met, solutions can be taken by installing cooling towers, improving indoor ventilation, and increasing the space in the computer room. You can also check if the cooling fan is working properly. If there is a malfunction, it should be repaired or replaced.

10. The main inspection for air-cooled units is to check whether the temperature difference between the inlet and outlet oil is around 10 degrees. If it is less than this value, the surface fins of the radiator should be checked for dirt and blockage. If it is dirty and blocked, clean air can be used to blow off the dust on the surface of the radiator, and check whether the radiator fins are corroded. If the corrosion is severe, it is necessary to consider replacing the radiator assembly and whether there is dirt and blockage in the internal pipes. If there is such a phenomenon, a circulating pump can be used to clean the radiator with a certain amount of acidic solution. It is important to pay attention to the concentration and circulation time of the solution to avoid the radiator from penetrating

11. There are issues with the fan of the air cooler, such as the fan not turning, the fan reversing, and only one of the two fans being turned on

12. Issues with the exhaust ducts installed by customers for air-cooled models

Is there an exhaust duct with a small air surface, a long exhaust duct, too many bends in the middle of the exhaust duct, and a long exhaust duct with many bends in the middle? Has an exhaust fan been installed? The flow rate of the exhaust fan is lower than the original cooling fan of the air compressor.

13. The temperature sensor reading is inaccurate

14. The computer reading is inaccurate

15. Head issue

Generally, the bearings of the air compressor head need to be replaced after 20000-24000 hours, because the clearance and balance of the air compressor are ensured by the bearings. If the wear of the bearings increases, it will cause an increase in heat generation in the air compressor head, resulting in high temperature of the air compressor.

16. Incorrect specification or poor quality of lubricating oil

The lubricating oil for screw machines has strict requirements and cannot be used arbitrarily. The requirements in the equipment manual should be followed.

17. Check if the air filter is clogged

Air filter blockage can cause excessive load on the air compressor, which can lead to high temperatures if it remains in a loaded state for a long time. It can be checked or replaced based on the alarm signal of the differential pressure switch. The first problem caused by clogged air filters is a decrease in gas production, with high temperatures in the air compressor being a secondary manifestation.

18. Check if the pressure is too high

The system pressure is usually set at the factory. If adjustment is necessary, the rated gas production pressure indicated on the equipment nameplate should be used as the standard. If the adjustment is too high, it will cause overheating due to the increase in machine load. This is also the same as the previous reason, where high temperature in the air compressor is a secondary manifestation, mainly manifested as an increase in the current of the air compressor motor and a shutdown of the air compressor protection.

19. Blockage of oil and gas separator

Blockage of the oil and gas separator can cause excessive internal pressure, which can lead to many problems, and high temperature is one of them. This is also the same as the previous two reasons, where the blockage of the oil and gas separator is mainly manifested by high internal pressure.