It is summer, and at this time, the high temperature faults of air compressors are frequent. This article summarizes various possible causes of high temperature.
1. The air compressor system is short of oil.
The oil level of the oil and gas barrel can be checked. After the 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 the operation of the equipment, the oil level cannot be lower than the low oil level mark L (or MIX). If it is found that the oil quantity is insufficient or the oil level cannot be observed, stop the machine immediately and refuel.
2. The oil stop valve (oil cut-off valve) is not working properly.
The oil stop valve is generally a two-position two-position normally-closed solenoid valve, which is opened 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 head and spray out from the air inlet when the machine is stopped. If the component is not turned on during loading, the main engine will heat up rapidly due to lack of oil, and in severe cases, the screw assembly will be burned.
3. Oil filter problem.
A: If the oil filter is clogged and the bypass valve is not opened, the air compressor oil cannot reach the machine head, and the main engine will heat up rapidly due to lack of oil.
B: The oil filter is clogged and the flow rate becomes smaller. In one case, the air compressor does not take away the heat completely, and the temperature of the air compressor rises slowly to form a high temperature. Another situation is the high temperature of the air compressor after the air compressor is unloaded, because the internal oil pressure of the air compressor is high when the air compressor is loaded, the air compressor oil can pass through, and the air compressor oil pressure is low after the air compressor is unloaded. The oil filter of the air compressor is difficult, and the flow rate is too small, which causes the high temperature of the air compressor.
4. The thermal control valve (temperature control valve) is malfunctioning.
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 due to the low oil temperature when starting up, the thermal control valve branch circuit is opened, the main circuit is closed, and the lubricating oil is directly sprayed into the machine head without the cooler; when the temperature rises above 40°C, the thermal control valve is gradually closed, The oil flows through the cooler and the branch at the same time; when the temperature rises above 80°C, the valve is completely closed, and all the lubricating oil passes through the cooler and then enters the machine head to cool the lubricating oil to the greatest extent.
If the thermal control valve fails, the lubricating oil may directly enter the machine head without going through the cooler, so that the oil temperature cannot be lowered, resulting in overheating.
The main reason for its failure is that the coefficient of elasticity of the two heat-sensitive springs on the spool changes after fatigue, and cannot operate normally with temperature changes; the second is that the valve body is worn, the spool is stuck or the action is not in place and cannot be closed normally. . Can be repaired or replaced as appropriate.
5. The fuel volume regulator is abnormal, and the fuel injection volume can be appropriately increased if necessary.
The fuel injection volume has been adjusted when the equipment leaves the factory, and it should not be changed under normal circumstances. This situation should be attributed to design problems.
6. If the engine oil exceeds the service time, the engine oil will deteriorate.
The fluidity of the engine oil becomes poor, and the heat exchange performance decreases. As a result, the heat from the head of the air compressor cannot be completely taken away, resulting in high temperature of the air compressor.
7. Check whether the oil cooler works normally.
For water-cooled models, you can check the temperature difference between the inlet and outlet pipes. Under normal circumstances, it should be 5-8°C. If it is lower than 5°C, scaling or blockage may occur, which will affect the heat exchange efficiency of the cooler and cause heat dissipation. Defective, at this time, the heat exchanger can be removed and cleaned.
8. Check whether the cooling water inlet temperature is too high, whether the water pressure and flow are normal, and check whether the ambient temperature is too high for the air-cooled model.
The inlet temperature of the cooling water should generally not exceed 35°C, and the flow rate should not be less than 90% of the specified flow rate when the water pressure is between 0.3 and 0.5MPA.
The ambient temperature should not be higher than 40°C. If the above requirements cannot be met, it can be solved by installing cooling towers, improving indoor ventilation, and increasing the space of the machine room. You can also check whether the cooling fan is working normally, and if there is any failure, it should be repaired or replaced.
9. The air-cooled unit mainly checks the inlet and outlet oil temperature
Is the difference about 10 degrees. If it is less than this value, check whether the fins on the surface of the radiator are dirty and clogged. If it is dirty, use clean air to dust the surface of the radiator and check whether the fins of the radiator are corroded. If the corrosion is severe, it is necessary to consider replacing the radiator assembly. Check whether the internal pipes are dirty or blocked. If there is such a phenomenon, you can use the circulating pump to circulate a certain amount of acid liquid to clean it. Be sure to pay attention to the concentration of the liquid and the cycle time to avoid the radiator from being pierced due to the corrosion of the liquid.
10. Problems with the exhaust ducts installed by customers of air-cooled models.
There are exhaust ducts with too small wind surface, too long exhaust ducts, too many bends in the middle of the exhaust ducts, too long middle bends and most of the exhaust fans are not installed, and the flow rate of the exhaust fans is smaller than that of the original cooling fan of the air compressor.
11. The reading of the temperature sensor is not accurate.
If the temperature sensor is completely disconnected, the device will alarm and stop, and display that the sensor is abnormal. If the work is bad, sometimes good and sometimes bad, it is much more hidden, and it is more difficult to check. It is better to use the substitution method to eliminate it.
12. The nose problem.
This general air compressor head bearing needs to be replaced every 20,000-24,000 hours, because the gap and balance of the air compressor are all positioned by the bearing. If the wear of the bearing increases, it will cause direct friction on the air compressor head. , the heat increases, resulting in high temperature of the air compressor, and it is more likely that the main engine will lock up until it is scrapped.
13. The specifications of lubricating oil are incorrect or the quality is poor.
The lubricating oil of the screw machine generally has strict requirements and cannot be substituted at will. The requirements in the equipment instruction manual should prevail.
14. The air filter is clogged.
The clogging of the air filter will cause the load of the air compressor to be too large, and it will be in a loaded state for a long time, which will cause high temperature. It can be checked or replaced according to the alarm signal of the differential pressure switch. Generally, the first problem caused by the blockage of the air filter is the reduction of gas production, and the high temperature of the air compressor is the secondary performance.
15. The system pressure is too high.
The system pressure is generally set at the factory. If it is really necessary to adjust, the rated gas production pressure marked on the equipment nameplate should be taken as the upper limit. If the adjustment is too high, it will inevitably cause overtemperature and overcurrent overload due to the increase in the load of the machine. This is also the same as the previous reason. The high temperature of the air compressor is a secondary manifestation. The main manifestation of this reason is that the current of the air compressor motor increases, and the air compressor shuts down for protection.
16. The oil and gas separator is blocked.
The blockage of the oil and gas separator will cause the internal pressure to be too high, which will cause many problems, and high temperature is one of them. This is also the same as the first two reasons. The clogging of the oil-gas separator is mainly manifested by high internal pressure.
The above are the possible high temperature causes of some screw air compressors summarized, for reference only.