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High Temperature in Summer, Maintenance of Screw Air Compressor (Part 1)

Time : 2022-06-22 Hits : 25

The hot summer is coming, and the high temperature of air compressor is one of the common faults in the use of air compressor. Aiming at this problem, we find out various potential causes and analyzes them.

1. Too high ambient temperature will affect the screw air compressor in the following two aspects

A: The higher the temperature is, the thinner the air is (just like the low efficiency of the air compressor in plateau areas), resulting in the decrease of the working efficiency of the air compressor, which makes the air compressor stay in the loading state for more time and carry more loads, resulting in more heat generated by the air compressor, and the air compressor must have a higher temperature.

B: Generally, there is a design operating ambient temperature (30-40 ℃) when the air compressor is designed. Generally, the maximum temperature of the air compressor operating under the design operating ambient temperature is 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, the temperature of the air compressor will be increased, so that the air compressor will even exceed the shutdown temperature of the air compressor, resulting in high temperature of the air compressor.

2. Air compressor system is short of oil

The oil level of the oil and gas tank can be checked. After shutdown and pressure relief, when the lubricating oil is static, the oil level should be slightly higher than the high oil level mark H (or max). During equipment operation, the oil level shall not be lower than the low oil level mark L (or mix). If the oil quantity is insufficient or the oil level cannot be observed, stop the machine immediately to refuel.

3. The oil stop valve (oil shutoff valve) does not work properly

The oil stop valve is generally a two position two normally closed solenoid valve, which is open when starting and closed when stopping, so as to prevent the oil in the oil and gas barrel from continuing to spray into the machine air end and from the air inlet during shutdown. If the element is not opened when loaded, the air end rapidly heat up due to lack of oil, and the screw assembly will be burned in serious cases.

4. Oil filter problem

A: If the oil filter is blocked and the bypass valve is not opened, the air compressor oil will not reach the machine air end, and the air end will rise rapidly due to lack of oil.

B: The oil filter is blocked and the flow becomes smaller. One case is that the air compressor is not completely taken away by heat, and the air compressor temperature slowly rises to form a high temperature. The other case is that the air compressor is high after unloading, because the internal oil pressure of the air compressor is high during loading, and the air compressor oil can pass through. After unloading, the air compressor oil pressure is low, and it is difficult for the air compressor oil to pass through the air compressor oil filter, The flow is too small to cause high temperature of the air compressor.

5. Thermal control valve (temperature control valve) fails to work

The thermal control valve is installed in front of the oil cooler to maintain the exhaust temperature of the machine air end above the pressure dew point. Its working principle is that when the machine is just started, due to the low oil temperature, the thermal control valve branch is opened, the main circuit is closed, and the lubricating oil is directly injected into the machine air end without passing through the cooler; When the temperature rises to above 40 ℃, the thermal control valve is gradually closed, and the oil flows through the cooler and branch at the same time; When the temperature rises above 80 ℃, the valve is completely closed, and the lubricating oil enters the machine air end through the cooler to cool the lubricating oil to the greatest extent.

If the thermal control valve fails, the lubricating oil may enter the machine air end directly without passing through the cooler, so the oil temperature cannot drop, resulting in over temperature. The main reasons for its failure are as follows: firstly, the elastic coefficient of the two thermal springs on the valve core changes after fatigue, and they can not operate normally with the change of temperature; Second, the valve body is worn, and the valve element is stuck or the action is not in place, so it cannot be closed normally. It can be repaired or replaced as appropriate.

6. Check whether the fuel volume regulator is normal. If necessary, increase the fuel injection volume appropriately

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

7. The engine oil has exceeded the service life, and the engine oil has deteriorated

The oil fluidity becomes poor, and the heat exchange performance decreases. The heat of the air compressor head cannot be completely taken away, resulting in high temperature of the air compressor.

8. Check whether the oil cooler works normally

For water-cooled models, the temperature difference between the inlet and outlet water pipes can be checked. Under normal circumstances, it should be 5-8 ℃. If it is lower than 5 ℃, scaling or blockage may occur, which will affect the heat exchange efficiency of the cooler and cause poor heat dissipation. At this time, the heat exchanger can be removed and cleaned.