Analysis of the reasons for the compressor's high temperature

1 The role of air system and equipment status

In the operating equipment of the compressor station, the air compressor is an indispensable device for providing pneumatic instruments and compressors for gas isolation. Due to production needs, air compressors operate under high load and high temperature conditions for a long time, and the number of downtimes is very high <2>. Because it is imported equipment, the price of damaged parts is very expensive, and the replacement process is also very cumbersome, which seriously affects normal production.

In order to better serve the production and reduce the loss, it is necessary to pre-control the air compressor fault and analyze a multi-function fault temperature and high fault of the air compressor.

2 Case Analysis of Temperature and High Fault of Double Screw Air Compressor

The twin-screw air compressor has extremely superior and reliable performance, low vibration, low noise, high efficiency, no wearing parts, and low operation and management costs. However, in the operation, there have been many high temperature failures. Now, the air-cooled 7.4 cubic model is used to analyze the causes of the high temperature failure of the twin-screw air compressor, and solutions and preventive measures are proposed.

Under normal circumstances, the exhaust temperature of the screw main unit should be between 75 and 95. If the exhaust temperature is too high, it will cause damage to many components and severely burn the main unit. The screw air compressors are designed with ultra-high temperature protection function. When the temperature sensor detects that the head exhaust temperature exceeds 109, the command temperature high switch (1ATS) acts, alarms and stops automatically, and the exhaust is displayed on the touch control panel. The temperature > 109, the standby air compressor starts running to ensure the normal isolation of the pneumatic instrument and compressor.

The cooling measure is to spray lubricating oil from the lower end and the two ends of the body into the compression chamber, and after being compressed together with the inhaled air, it is discharged from the bottom of the main machine to the oil separator. In addition to lubricating the screws and bearings, gears and other parts, it also has a large amount of tropical. However, when the heat has not been transferred, the cooling of the coolant cooler is required before the next injection operation to complete the cooling. Therefore, the occurrence of temperature and high faults is mostly related to the abnormality of the lubrication and cooling system. The following is a summary of the causes of the faults and the corresponding countermeasures from the three parts that generate the high temperature faults.

2.1 Pressurized cooling oil system with cooler, pressurized cooling oil system with cooler in oil and gas separation system and oil supply component air compressor, insufficient oil quantity of oil and gas separation system and oil supply component or oil circuit component Abnormal operation will cause the oil temperature to rise, causing a high temperature fault.

(1) The coolant level is low. During operation of the equipment, the liquid level in the oil separator is not lower than the low oil level mark L (or min). If it is found that the coolant is insufficient or the liquid level is not observed, stop immediately and refuel.

(2) Insufficient oil supply. First check the coolant filter and check if the oil separator is clogged. Judging from the differential pressure before and after loading, when the differential pressure at both ends is 3 times at the beginning of the start-up or the maximum differential pressure reaches 01 MPa, it should be cleaned or replaced.

(3) The oil shutoff valve is not working properly. The oil shut-off valve (5SV coolant shut-off solenoid valve) is generally two-position two normally closed solenoid valves, which are opened at start-up and closed during shutdown to avoid oil from the oil separator continuing to be injected into the machine head during shutdown and from the air inlet. Squirting, causing oyster sauce. If the component fails, the main engine will heat up quickly due to lack of oil after the compressor is started. It will automatically stop after 1min, and the screw assembly will be burnt if it is serious. After the air compressor stops, remove the oil shut-off valve and gently push the valve stem to see if it can be pushed forward and backward and can be easily reset. If it is difficult to pull or pull back, it is necessary to further disintegrate the oil shut-off valve. If the valve stem or valve hole is oily, it needs to be sanded with fine sandpaper to make it easy to slide; if the spring is broken or there is foreign matter stuck, it will affect the movement of the valve stem. In this case, the spring or the cleaning spring and the spring seat need to be replaced.

(4) The temperature control valve fails to work. The thermostatic valve is mounted in front of the oil cooler and functions to maintain the head exhaust temperature above the pressure dew point. If the temperature control valve fails, the lubricating oil may enter the machine head directly without the cooler, so that the oil temperature cannot be lowered, resulting in a high temperature. The main reason for its failure: the size of the two thermal springs on the valve core after the fatigue coefficient changes, can not move normally with the temperature changes; the valve body wears, the valve core is stuck or the action is not in place and can not be closed normally. Can be repaired or replaced depending on the situation.

(5) The quality of the lubricating oil is poor. The lubricating oil of the screw machine generally has strict requirements and cannot be replaced at will. The requirements in the equipment manual shall prevail. The manufacturer recommends the use of SSR Super Coolant, which is a base of ploygiycol coolant that needs to be replaced every 8000h or every 2 years (regardless of which condition is reached first).

2.2 cooling system

The cooling method of the screw air compressor is water-cooled and air-cooled.

The air compressor at the Fugu pressure station is air-cooled. Check the following steps: First, check if the air cooler is working properly. The temperature difference between the inlet and outlet pipelines can be checked. Under normal conditions, it should be 5~80. If it is lower than 5, there may be scaling or clogging, which will affect the heat exchange rate of the cooler and cause poor heat dissipation. When cleaning the cooling fan heat exchanger, it is best to remove the heat exchanger and clean it. Fugu station is located in a windy, dusty environment. Since June, the station has been in high temperature, and the ambient temperature in the air compressor room is as high as 40 or more. This has caused the high temperature of the 2# air compressor at the Fugu station. After the nitrogen purge of the station, the effect is not obvious. Finally, the domestic water in the station is used for cleaning. After washing with water, the effect is obvious. So far, the 2# air compressor has been running for more than one month. The current operation is still stable and the temperature is always Stay at around 85.

Second, check if the ambient temperature is too high. The ambient temperature should not be higher than 46 (not less than 17, if the temperature is too low, it will cause fouling or blockage). If the above requirements are not met, the axial flow fan can be installed to improve indoor ventilation and increase the space of the machine room.

2.3 air suction, scheduling and control pipeline components

Inaccurate movement of components such as air suction, scheduling, and control line components can cause compressor malfunction and high temperature failure. You can check by the following steps:

(1) Check if the air filter is clogged. With the IND mechanical air filter spring indicator, when the spring indicator jumps to the red area, it needs to be replaced in time.

(2) Check if the pressure is too high. The system pressure is generally set at the factory. If it needs to be adjusted, it should be based on the rated gas pressure of the equipment nameplate. If the adjustment is too high, the temperature will increase due to the increase in the load on the machine.

(3) Check if the intake valve works normally. Due to the large fluctuation of the gas consumption in the pipe network, the intake valve controls its action through the BFV air inlet control valve to adjust the suction amount, and realizes no-load or load operation through the 1SV loading solenoid valve and the 3SV venting solenoid valve. To achieve the purpose of energy saving. If the above components fail, the main unit may not be able to adjust and remain in no-load (no inhalation) or loading state. If it is always loading, a high temperature phenomenon may occur. In addition, when the amount of gas used in the field equipment is always greater than the gas production capacity of the air compressor, it will not be unloaded. At this time, the problem can only be solved by increasing the gas generating capacity of the air compressor station.

3 Conclusion

Air compressor temperature alarm is a common fault. The occurrence of faults not only affects production, but also increases the loss of spare parts and shortens the life of equipment. In addition, it will accelerate the deterioration of oil products, such as reduced lubrication performance, decreased flash point, etc. Sometimes high temperature will cause spontaneous combustion of oil, resulting in air compressor burning and even explosion accidents. Therefore, we should attach great importance to various problems in the operation of equipment, and take a series of measures to prevent temperature and high faults in advance, appropriately improve the working environment of the air compressor room and use the station control system to monitor the working conditions of the equipment at any time to completely eliminate Safety hazards to ensure smooth operation of gas production.

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