What are the reasons for the high temperature of the air compressor

The air compressor is a transmission machine. If the equipment running at high speed is not properly lubricated or cooled, it will inevitably produce high temperature. Excessive temperature will cause changes in the physical coefficient values ​​of the rotor and bearing materials, and in severe cases, the entire main engine will bite. Dead, although air compressor manufacturers have installed protection devices for high temperatures, the existence of faults will cause the protection devices to operate frequently and affect the normal production of customers.

There are many situations that cause the high temperature of the air compressor. If you blindly find the root cause of the failure, it will not only have low efficiency and waste human and material resources, but more importantly, it will leave an unprofessional impression on the customer, and even lose the opportunity for the next cooperation.

This site has conducted years of research and exploration on the fault. After many on-site operations, a set of oil-injected screw air compressors have been integrated to quickly find the source of high-temperature faults for your reference:

First of all, we have an understanding of the temperature of the oil-injected screw air compressor: usually the oil-injected screw compressor should work at 65 ̴ 98 ℃. If the oil temperature is too low, it will affect the decomposition of oil and water, leading to oil emulsification and reducing lubricating oil. Too high oil temperature will reduce the gas transmission coefficient and increase power consumption, the viscosity of the lubricating oil will decrease, causing abnormal friction loss in the bearing, and even bearing loose beads accidents, too high temperature will also make the lubricating oil in the metal Thermal decomposition occurs under catalysis, generating harmful free carbon, acids and moisture (carbon formation), which will cause the screw to jam in severe cases.

The oil circulation process can be understood as two paths, namely from the nose to the oil and gas separation tank to the oil and gas separator to the one-way valve to the nose; and the other oil circuit can be divided into two processes, namely the nose to the oil and gas separation tank to From the temperature control valve to the oil filter to the machine head, when the temperature exceeds the operating value of the temperature sensing element of the temperature control valve (generally it operates at 71℃), the oil circuit circulation process is: the machine head to the oil and gas separation tank to the temperature control valve to the oil cooling From the device to the thermo valve (combined) to the oil filter to the machine head.

If all the above are understood, then we can enter the topic to analyze the temperature difference of the connecting pipes (A, B, C, D pipes) of the temperature control valve to determine the source of high temperature:

1) At high temperature: Firstly, it is necessary to rule out whether the machine head itself is malfunctioning. The judgment method is: to understand whether the machine head has been overhauled recently, whether the lubricating oil is genuine, whether the unit lubricating oil is too low, and whether there is any feeling after turning off the hand disc rotor Stuck, after starting up, observe whether the vibration of the whole machine is too high, whether there is abnormal noise in the machine head, if the high temperature is caused by the above reasons, the oil circuit should be normal, and the temperature values ​​of the oil pipes A and C are close because the equipment is at high temperature. Therefore, the temperature control valve is in a fully working state, and the temperature difference between solid D and B points is also close.

And it is significantly lower than points A and C (normal temperature difference can be calculated by parameters such as fan, cooler material, heating area, etc.);

Note: Points D and B are connected under any circumstances. Some temperature control valves have only three interfaces, while point D is directly connected to the B pipe with a three-way connection.

Analysis: At this time, the temperature control valve is in a normal state. The lubricating oil flows from the oil and gas separation tank to points A and C, and flows to points D and B after being cooled by the cooler. After the oil merges at points D and B, it flows to the oil filter for oil purification. Finally back to the machine head, so the oil temperature difference at this time should be A≈C. Because the equipment is in a high temperature state, the solid temperature control valve is in a fully open state, so D≈B, A, C>D, B;

2) At high temperature: If the temperature of point D and B is excessively lower than A, C, check whether the oil filter is blocked;

Analysis: The oil filter is clogged: The oil circuit is the same as the above, except that the oil filter is clogged to reduce the lubricating oil flow. At this time, the oil at points D and B stays in the cooler for a long time to cool, and the The temperature at point B is very different from the temperature at points A and C. The high temperature is because there is too little oil to the nose, which cannot meet the amount of oil required for cooling the nose.

3) At high temperature, if the temperature at point D is slightly lower than point B, and the temperature at point B is only slightly lower than points A and C, the spool of the temperature control valve cannot be fully opened. At this time, check the temperature control valve;

Analysis: The above has analyzed the normal state of the oil circuit. If the temperature at point D is slightly lower than point B, and the temperature at point B is only slightly lower than points A and C, it proves that the temperature control valve spool has not been fully opened. The lubricating oil should flow from the oil-gas separation tank to point A, part of the lubricating oil to point C, and part of the lubricating oil to point B. The oil at point C flows to point D and merges with point B after being cooled by the cooler, and then flows to the machine through the oil filter. Head, so A≈C>B>D;

4) At high temperature, the temperature of point D and B is slightly lower than point A and C, check the cooling system of the cooler at this time;

Analysis: The cooling effect of the cooler is not good: At this time, the lubricating oil should flow from the oil-gas separation tank flow point through the cooler flow direction point, and then flow through the oil filter to the machine head. Because the cooler is unlikely to fail, there is still a slight temperature difference. So

5) At high temperatures, if the temperatures at points A, B, and D are close, the temperature at point C is significantly lower than points A, B, and D, which proves that the temperature control valve is not working; Analysis: The temperature control valve has no action: At this time, the oil path flows from the oil and gas separation tank to point A. Because the temperature control valve does not operate, the oil at point A flows directly to point B through the oil filter, because point B is connected to point D by the pipeline. Point communicates with point C but there is a cooler in the middle, solid A≈B≈D>C;

6) At high temperatures, if the temperature values ​​of points A, B, C, and D are close, there are many reasons at this time, such as the radiator does not work, and the cooling fan does not work.

Analysis: The radiator does not work (such as serious scale on the radiator wall): At this time, the lubricating oil flows from the oil and gas separation tank to points A and C, through the cooler to points D and B, and the oil flows to the oil after the points D and B merge. The filter performs oil purification, and finally returns to the machine head. Because the cooler does not play a role in heat dissipation, solid A≈C≈D≈B;

The cooling fan is not working: the fault can be found by naked eyes, and the oil path is the same as the oil path where the radiator is not working