As the leading equipment in industrial applications, compressed air system devices are the backbone of many industrial product systems. Clean and dry compressed air provides stable and reliable pressure to the gas equipment, and the performance and efficiency of the equipment will be improved, thus directly reducing production costs. . However, some companies focus on the main products and equipment, but they do not recognize the importance of the air system. The management and maintenance are not in place, which makes the air compressor equipment in the hidden troubles, causing unnecessary losses to the production operation. . Through long-term operation and maintenance, the author introduces the maintenance and repair experience of some air compressors through the analysis and treatment of two faults.

2 Failure Analysis One reason was that a company was completed and put into operation in October 2007, and the air compressor was put into operation. The gas supply system consists of three Ingersoll Rand twin-screw water-cooled units, three micro-heat dryers and two gas storage tanks. The operation mode is two open and one standby.

At the end of 2009, all the units were put into operation due to the increase in gas consumption.

In the second half of 2010, the temperature of the oil and the temperature of the exhaust gas increased on the No. 1 machine. The oil consumption was very high. Almost every month, 2 to 3 barrels of oil (5 gallons/barrel) were added, and the oil temperature reached at the beginning of September. 106*C, continuous alarm, unable to run.

Considering that the unit has been in production for less than 4 years, there should not be many failures. First, the cooling problem should be suspected. After investigation, it was found that the three air compressor coolers were blocked several times, and the scale was removed once in about 2 months (the upper cover of the cooler was opened several times, and the ventilation was used to clear the passage). The maintenance technicians fixed the end of the temperature-controlled spool to perform forced cooling, but the cooling effect was better in the first few weeks after the descaling of the cooler, and then rapidly deteriorated, and the oil temperature and exhaust temperature increased rapidly; the control system can According to the regulations, the air compressor oil and oil filter were replaced in early September.

According to the above phenomenon, it can be concluded that the oil cooler is clogged, so the oil removal cooler is arranged to inspect the pipeline. After disassembling, it was found that 16 copper pipes were blocked. The lower cover (returning to the water end) was dismantled, and it was found that a piece of plastic paper and two pieces of woven bag fragments blocked some of the copper pipe inlets, and cleared a large amount of dust and black sand to unblock 8 pieces, and the remaining 8 pieces could not be dredged. According to the above phenomenon, it is possible to have problems with the circulating water system. First, the company's circulating water system was examined. The company is located on a slope. The circulating water system is located in the middle, and a large amount of gray powder is piled up within 200m. The cooling tower is built on the ground, the system is open, the air compressor cooler is very likely to be blocked and therefore belongs to the key suspects; then the circulating water system is checked, the system has a filter, and the analysis considers that the dust belongs to the silicon powder and the magnetite particles, and The circulating pool has not been cleaned up since its establishment. All the above analysis and inspections prove that the problem of the machine is indeed in the cooling, because the cooler is still in the state after the dredging: the failure analysis of the twin-screw air compressor is not more than 20%, and the cooling effect does not change much.

Then arrange the reloading test, but after 10 minutes, the oil temperature and exhaust temperature rise again, and the oil temperature reaches 106*C and the alarm stops.

Observe the air compressor pipeline, and find that the cooling water return pipeline has a thinner diameter, poor drainage and green color; the trap is not used for a long time, the dryer is drained a lot, and a thick layer of oil floats on the surface of the sewage; the surface of the cooler The surface of other components is covered with black oil, indicating a large fuel consumption. Facts have proved that the problem is not simply a cooling problem. After further analysis, it was found that the summer high-temperature cooperative maintenance factory recommended that the company's maintenance personnel expand the oil on the nose back to increase the oil return. In the above description, the oil return pipe is easily clogged due to the low cooling efficiency, and the pipe related to the lubrication of the head may be clogged. Due to the lack of more inspection data, in view of the complexity of the problem, the direct cause of high temperature of No. 1 machine after eliminating other reasons may be in three aspects: (1) shaft seal leakage; (2) shaft end friction; (3) ) Bearing loose beads. The next day the machine returned to the factory to overhaul the bearing and shaft seal, and returned to the installation test after 3 days.

3 Fault 2 Analysis The operation of an aluminum processing plant 2 air compressor (Sullair 300HP twin screw water cooling) has been very stable, but P3LOW is reported when the machine is restarted after 24 hours of shutdown. According to past experience, considering that the machine has been running for 2 years, the oil filter and engine oil have exceeded the replacement cycle, and there may be a large viscosity of the oil. It should be able to operate normally after two consecutive starts. But then did not start successfully, are reported P3LOW around 6s start, then automatically stop, if you continue to start the machine head may be lack of oil, will cause host failure.

(1) The temperature is low, the minimum starting temperature of the model is 5C, which is most likely to occur in winter; (2) the minimum pressure valve is faulty, causing the internal pressure to be too low to reach 0.35MPa, causing the injection pressure to be too low; (3) The vent valve is faulty, the oil separator pressure is low, causing the fuel injection pressure to be too low; (4) The temperature control valve is faulty, a large amount of oil enters the cooler, the oil temperature is too low, the viscosity is large, and P3LOW appears; (5) the oil filter plug is blocked The injection pressure P3 is low, and the P3LOW alarm is stopped. For the above reasons, the following measures are required: (1) The indoor temperature should be increased in the winter, so that the indoor temperature reaches 5C or more, so that the equipment and oil temperature are balanced; (2) the minimum pressure per year. The valve is maintained once, and the check is strengthened to prevent the valve from malfunctioning. (3) Strengthen the maintenance and check of the vent valve to prevent the valve from malfunctioning; (4) Observe the action of the temperature control valve when starting the machine, and observe the oil at the same time. Judging the working condition of the temperature control valve, periodically using the temperature measuring instrument to detect and compare the accuracy of the temperature sensor; (5) Recording the replacement date of the consumables, and regularly changing the oil filter; (6) Timing maintenance of the loading and unloading mechanism Check the lubrication to prevent leakage, blockage, jamming, and fasteners falling off; (7) If the oil temperature rises rapidly during start-up, and the host emergency stop can be judged as the oil shut-off valve failure; (8) Check the intake valve Action to determine the position of the intake valve.

According to the above analysis and comparison, it is necessary to use the exclusion method to solve. First check the consumable replacement record, the oil filter is running for 2000h, need to be replaced; replace the filter element and check the oil level is normal. Start the 2 machine according to the normal startup procedure, firstly convert the star to the triangle for 6s, then transfer the program to the loader. Observe that the control panel displays about 15 s. P1 only reaches 0. 35MPa, indicating that there is a problem with the control system, but the device action description controls the solenoid valve. According to the specified action, the control pipeline is not blocked; there may be a problem in the intake control section. When the cover is opened, it is found that the control cylinder does not move, the lever extends slowly, and it protrudes when it is about 18 s, and the air compressor immediately enters the full load state; Then enter the loading and unloading adjustment conditions, observe the control panel shows P1, the maximum pressure of P2 reaches 0.81MPa, and the set working state is P2 reaches 0.7MPa unloading, this working condition is extremely abnormal. Careful observation of the loading process revealed that the cylinder was deflected as a whole during loading, and returned to its original position during unloading, and the cylinder head was worn at the end. After the shutdown and pressure relief dismantling, it was found that the two bolts of the fixed Shouli control had a fracture, which was a fatigue fracture, which made the bracket unable to fix the position of the Shouli control, resulting in the cylinder not being able to be loaded and unloaded according to the normal action. Quickly extended, not extended above the limit screw, so that the opening of the inlet butterfly valve is too large, P1 instantly rises to 0.81 MPa. After the new bolt is tightened, it is restarted, and the above abnormality does not reappear.

The above analysis shows the process of solving the problem. Even in the case of experienced experience, it is necessary to strengthen the equipment inspection and analysis system to improve the equipment support ability to serve the production operation.

-), male, Luoyang, Henan, graduated from Luoyang University in 2000, majoring in mechanical manufacturing technology and equipment.

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