Analysis and solution of main faults of oil injection screw compressor

Analysis and solution of main faults of oil injection screw air compressor At present, in many mechanical industries in China, screw air compressor is widely used If the operation of screw air compressor is not accurately judged and the possible faults are predicted in time, a large number of problems may occur in screw air compressor, which is difficult to operate and use normally and smoothly Therefore, it is very important to analyze the faults of screw air compressor in detail, and put forward effective treatment methods to ensure the normal and stable operation of screw air compressor Advantages of oil injection screw air compressor 1 oil injection screw air compressor has the advantages of high stability, high efficiency, small vibration, low noise 2 The fit between the male and female rotors and the rotors and the casings is set, so that the gas return leakage is less, and there is no clearance volume at the same time, so the efficiency is high 3 The injected lubricating oil has the functions of sealing, cooling and lubricating 4 There are few parts, no suction and exhaust valve 1 Host: world * brand, excellent performance, reliable operation 2 Motor: the efficiency of class F air-cooled motor exceeds the effl standard 3 Transmission system: the motor drive end is lubricated by compressor oil, with high efficiency, maintenance free and high reliability 4 Fan: large cooling air volume and low noise 5 Heat dissipation system: plate fin structure and materials are used to ensure the pressure resistance of the cooler, high heat dissipation efficiency and good corrosion resistance 6 Air filter: heavy duty, multistage air inlet filter, dust removal accuracy 1um (99% filtered), large contact surface, long service life 7 Oil / gas separator: the new generation of separator adopts new filter material, with higher efficiency and air oil content less than 1ppm 8 Intelligent controller: all operation and relevant data of the air compressor operation are displayed on the control panel and controlled between your fingers as much as possible, easy, convenient and accurate High performance and high efficiency air compressor equipment screw type air compressor adopts high capacity compression components, its rotor outer circle speed is low and Zui oil injection is good, achieving high efficiency and reliability The new Zui design ensures extremely low system temperature and compressed air temperature Ensure that all parts have good cooling effect and high service life Maintenance free, highly reliable and efficient driving concept air compressor equipment screw air compressor drives the compression components through the transmission system at a good speed suitable for the use of Zui No maintenance is required at all during normal operation Low maintenance cost compressor design of screw air compressor saves unnecessary maintenance cost All parts are designed with long life Large size inlet filter, oil filter and fine separator ensure the quality of Zui compressed air All oil filters and separator components within 22KW (30HP) are centrifugal open and close, and the maintenance time is further reduced "Fast maintenance point" enables the maintenance work to be completed in a few minutes, and reduces the downtime and maintenance costs Built in intelligent control to reduce operating costs, precise operation control is essential All machines are equipped with intelligent control system, and the control menu is simple and easy to use However, it may also have over temperature, high operating current and insufficient air volume during operation This paper focuses on the analysis of the causes of over temperature failure of screw air compressor, studies its solutions and preventive measures, and puts forward several other common troubleshooting methods Cause analysis of over temperature fault under normal conditions, the exhaust temperature of the main screw should be between 75 ℃ and 95 ℃ When the exhaust temperature is lower than the pressure dew point, there will be condensation, which will cause more moisture in the system, emulsification of lubricating oil and affect the lubrication effect If the exhaust temperature is too high, many components will be damaged and the main engine will be burned seriously Screw air compressors are designed with ultra-high temperature protection function Once the exhaust temperature exceeds 100 ℃ or the set temperature, the temperature sensor will command the temperature switch to act, send out an alarm and automatically stop the machine At the same time, the exhaust temperature can be read on the instrument panel is greater than 100 ℃ The cooling measure of the machine itself is to spray lubricating oil into the compression chamber from the lower end and left and right ends of the machine body After being compressed together with the inhaled air, the lubricating oil will be discharged from the bottom of the machine to the oil and gas barrel It not only lubricates the screw, bearing, gear and other parts, but also brings out a large number of tropics However, before the heat is transferred, before the next injection action, it needs to pass through the oil cooler to cool down completely Therefore, the occurrence of over temperature fault is mostly related to the abnormality of lubrication and cooling system The following analysis one by one: 1 Insufficient lubricating oil or abnormal operation of oil circuit components will increase the oil temperature, resulting in over temperature fault For example: (1) insufficient oil supply: first, check whether the oil filter and oil fine separator are blocked Secondly, check whether the fuel quantity regulator is normal If necessary, increase the fuel injection quantity properly (2) the oil stop valve does not work normally: the oil stop valve is generally a two position, two normally closed solenoid valve, which is opened when starting and closed when shutting down, so as to prevent the oil in the oil and gas barrel from continuing to spray into the machine head and ejecting from the air inlet when shutting down (3) failure of thermal control valve: the thermal control valve is installed in front of the oil cooler to maintain the exhaust temperature of the head above the pressure dew point The main reasons for the failure are as follows: first, the elasticity coefficient of the two thermal springs on the valve core changes after fatigue, and they can not act normally with the change of temperature; second, the valve body is worn, the valve core is stuck or the action is not in place, and they can not be closed normally It can be repaired or replaced according to the situation (4) the specification of lubricating oil is incorrect or the quality is poor 2 Misoperation of such components as air suction head, schedule and control pipeline components will cause abnormal operation of air compressor and over temperature fault (1) check whether the air filter is blocked It can be checked or replaced according to the alarm signal of the differential pressure switch (2) check whether the pressure is too high Generally, the system pressure has been set at the time of delivery If it is necessary to adjust, the rated gas production pressure marked on the equipment nameplate shall prevail If the adjustment is too high, it will cause over temperature due to the increase of the load of the machine Common faults of lubricating system and oil circuit components insufficient lubricating oil or abnormal operation of oil circuit components will increase the oil temperature and cause over temperature fault 1 If the oil supply is insufficient, first check whether the oil filter and oil separator are blocked The oil separator is made of multi-layer glass fiber, and the filtering accuracy can reach 0.1 μ M its purpose is to filter the oil mist in the compressed air and prevent the loss of lubricating oil When the environment is poor and there is a lot of dust, the replacement cycle should be shortened properly The oil filter and oil fine separator are designed with differential pressure switch, which can automatically determine whether the filter is blocked by detecting the differential pressure at both ends of the filter If the filter is blocked, replace the filter and separator in time Secondly, check whether the fuel quantity regulator is normal If necessary, increase the fuel injection quantity properly The fuel injection quantity has been adjusted when the equipment leaves the factory, which should not be changed in general 2 The thermal control valve is installed in front of the oil cooler to maintain the head exhaust temperature above the pressure dew point Its working principle is that when the machine is just started, due to the low oil temperature, the branch of the thermal control valve is opened, the main circuit is closed, and the lubricating oil is directly injected into the machine head without the cooler When the temperature rises above 67 ℃, the thermal control valve is gradually closed, and the oil flows through and rises above 70 ℃ from the cooler and branch at the same time, the valve is completely closed The lubricating oil enters the machine head through the cooler to cool the lubricating oil to a large extent by Zui If the thermal control valve fails, the lubricating oil may enter the machine head directly without cooler, so that the oil temperature cannot be reduced, resulting in over temperature The main reason for the failure is that the elastic coefficient of the two thermal springs on the valve core changes after fatigue, and they can not act normally with the change of temperature Second, the valve body is worn, the valve core is stuck or the action is not in place, so it cannot be closed normally It can be repaired or replaced according to the situation The quality of the lubricating oil has a direct impact on the operation of the oil injection screw air compressor Generally speaking, the factors that affect the quality of the lubricating oil of the air compressor are as follows: 1 Inhale the particles such as iron oxide and carbon dioxide in the air to accelerate the deterioration of the lubricating oil; 2 In the process of oil change, the air compressor fails to drain all the old oil and mix it with the new oil to affect the service life of the lubricating oil; 3 The air compressor operates at a high temperature to accelerate the oxidation and deterioration of the lubricating oil; 4 The operation temperature of the air compressor is too low, which causes the exhaust temperature of the air compressor to be lower than the dew point temperature The moisture in the air is condensed and then mixed into the lubricating oil, so that the lubricating oil will produce emulsion Countermeasures: (1) the suction port of the air compressor shall be clean as far as possible to reduce the suction of impurities and avoid the deterioration of the lubricating oil due to impurities; (2) the lubricating oil shall be changed regularly in strict accordance with the requirements of the air compressor manufacturer, and the lubricating oil shall be sampled and analyzed regularly to confirm whether the oil quality is normal and whether it needs to be changed For economic reasons, it is not allowed to change the lubricating oil regularly as required, but to fill the lubricating oil regularly This will cause excessive viscosity of lubricating oil, poor heat dissipation performance, air compressor head temperature will rise At the same time, different brands of lubricating oil can not be mixed When the quality and brand of different lubricating oil are mixed, the performance of lubricating oil will be reduced, viscosity and deep sediment will be produced, the lubricating oil system will be blocked, the transmission of lubricating oil will be affected, and air compressor failure will be caused (3) ensure that the head temperature of the air compressor is within the set range, and timely adjust in case of any abnormality, so as to avoid deterioration of the lubricating oil due to poor working conditions High oil consumption 1 Causes of high oil level: the oil level of the oil tank of the air compressor has certain requirements If it is too low, the air compressor head temperature will be high; if it is too high, the oil and gas discharged from the air compressor head cannot be completely separated, and some lubricating oil will be brought out with the air flow, resulting in high oil content of the compressed air at the outlet of the air compressor, and the oil consumption of the air compressor will increase Countermeasures: ensure that the oil level of the air compressor is kept within a reasonable range during normal operation to avoid such failures 2 Failure reason of Zui small pressure valve: the opening value of Zui small pressure valve of air compressor of each manufacturer is regulated by pressure For example, the seal of Zui small pressure valve has leakage point, which is opened in advance or can't be closed completely, which increases the time of initial pressure establishment of air compressor oil separator Zui, the concentration of gas oil mist in low pressure state is high, the flow rate through oil time-sharing is fast, the oil load is heavier, the separation effect is reduced, and the oil consumption is increased Countermeasures: during the normal startup, observe the boosting process of the air compressor, such as the normal pressure with slow or no boosting, and the oil consumption of the air compressor is high, it is necessary to check and repair the Zui small pressure valve 3 Causes of oil separator failure: after the compressed air discharged from the air compressor head enters the oil separator, the oil and gas casings can be completely separated only after the oil baffle and oil separation core are separated twice If the oil baffle or oil separation core breaks down or fails, the oil and gas charge cannot be completely separated, resulting in high oil content of compressed air at the outlet of air compressor and increased oil consumption of air compressor Countermeasures: the oil baffle needs to be opened to check whether it is normal The oil separation core can pass through the front of the oil separator