Routine maintenance of screw air compressor

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The maintenance work of screw compressors is relatively standardized and clear, and replacement of accessories is simple and easy. Daily maintenance work mainly includes the following aspects:: 　 Daily maintenance content: 　 Check oil level ； 　 Check air filter and coolant level ； 　 Check hoses and all fittings for leaks ； 　 Check that the consumable parts have reached the replacement cycle and must be replaced by shutting down the machine. ； 　 Check the exhaust temperature of the main engine. If it reaches or approaches 98°C, the oil cooler must be cleaned. ； 　 Check the pressure difference of the separator. When it reaches above 0.6 Bar (limit 1Bar) or the pressure difference starts to decrease, the machine should be stopped and the separation core should be replaced. ； 　 Check the condensate discharge situation. If it is found that the discharge volume is too small or there is no condensate discharge, the water separator must be shut down and cleaned. ； 　 Check whether the air compressor makes any abnormal noise. 　 Monthly maintenance content: 　 Check the cooler and clean if necessary ； 　 Check all wire connections and tighten them ； 　 Check AC contactor contacts ； 　 Clean the dust on the surface of the motor air inlet and the surface of the casing ； 　 Clean return oil filter ； 　 Check whether the air compressor settings and operation are consistent. 　 Quarterly maintenance content: 　 Clean the main motor and fan motor ； 　 Replace oil filter element ； 　 Clean cooler ； 　 Check the minimum pressure valve and safety valve ； 　 Check the sensor. 　 Annual maintenance content: 　 Replace lubricating oil and oil-gas separator filter element ； 　 Replace air filter element, oil filter ； 　 Safety valve calibration ； 　 Check elastic coupling ； 　 Check cooling fan ； 　 Clean automatic drain valve ； 　 Replenish or replace motor grease. 　 Lubricating oil inspection and replacement have a decisive impact on the performance of oil-injected screw compressors. If used improperly or incorrectly, it will cause serious damage to the compressor body. Lubricating oil must be replaced in time, otherwise the quality of the oil will decline and the lubrication performance will be poor, which may easily cause tripping due to high temperature. At the same time, because the ignition point of the oil decreases, it is also easy to cause spontaneous combustion of the oil and cause the air compressor to burn out. When the following changes occur in the lubricating oil, the oil should be changed: 　 Moisture content greater than 0.1% ； 　 Acid value greater than 2 mg KOH/g ； 　 Kinematic viscosity change exceeds 10% of the allowable value ； 　 Color changes to brown-black. 　 When changing oil, the unit should be still hot and the oil and gas separator is depressurized. First, drain the oil in the oil and gas separator, and then inject new oil into the oil and gas separator. After the oil level on the liquid level gauge is higher than "70", tighten the oil plug. Be careful not to add too much oil, otherwise the excess oil will be carried away by the air. When changing the oil, the oil filter should be replaced at the same time. When replacing the oil filter, apply a layer of oil on the rubber sealing ring of the new oil filter and tighten it. 　 Usually mineral-type lubrication requires oil change after 2500 hours of cumulative operation. However, if the operation is less than 2500 hours in a year, the oil must also be changed after one year. Draining lubricating oil should be done immediately after the compressor is stopped, so that the tiny particles suspended in the oil can be discharged out of the machine along with the lubricating oil. 　 Notice: Regarding the maintenance details of the compressor, please read the accompanying instruction manual carefully. Analysis and Treatment of Common Faults of Screw Air Compressor. Once the compressor fails, it will not be difficult to analyze and eliminate the cause of the failure if you have a familiar understanding of the principle and structure of the compressor. Analysis of faults should start from the easiest and most convenient place. The following introduces the analysis and treatment methods of several common faults. 　 Compressor not loading: 　 1) The pressure on the gas pipeline exceeds the rated load pressure and the pressure regulator is disconnected. No measures are necessary. When the pressure on the gas pipeline is lower than the loading (position) pressure of the pressure regulator, the compressor will automatically load. ； 　 2) The solenoid valve fails. Remove it, check it, and replace it if necessary. ； 　 3) There is leakage in the control pipeline between the oil and gas separator and the unloading valve. Check the pipeline and connections. If there is leakage, repair it. Exhaust pressure is too low: 1) Check whether the two-position manual valves and pressure gauges "before separation" and "after separation" are leaking. If there is leakage, the leakage fault should be eliminated or the manual valve should be replaced. ； 　 2) Check whether the regulating solenoid valve is leaking. If it is leaking, troubleshoot and replace the regulating solenoid valve if necessary. ； 　 3) If the air consumption exceeds the exhaust volume, check whether there is any leakage in the pipeline. If there is any leakage, eliminate the leakage point or reduce the air consumption. ； 　 4) Check whether the air filter element is blocked and clean or replace it if necessary. ； 　 5) Check whether the safety valve is leaking. If it is leaking, eliminate it and replace it if necessary. ； 　 6) Check whether the butterfly valve is fully open and whether the air intake regulator is working properly. If there is any problem, replace or readjust the pressure switch. ； Check whether the upper and lower limits of the pressure switch are normal and adjust if necessary. ； 　 7) If the compressor fails, contact the manufacturer and check the compressor after consultation. 　 Exhaust pressure is too high: 1) Check whether there is any mechanical failure in the butterfly valve mechanism. If so, the fault should be eliminated. ； 　 2) Check whether the loading solenoid valve is leaking. If it is leaking, troubleshoot the problem and replace the solenoid valve if necessary. ； 　 3) Check and adjust the upper and lower limits of the pressure switch, and replace the pressure switch if necessary. 　 Exhaust temperature is too high: 1) Check whether the exhaust pressure exceeds the specification. If it exceeds the specification, adjust it to the specified exhaust pressure. ； 　 2) Check whether the lubricating oil is clean and whether the oil level is normal. If necessary, replenish or replace the lubricating oil. ； 　 3) Check whether the fan motor speed is normal and whether the exhaust port is blocked ； 　 4) Check whether the appearance of the oil cooler and after-cooler is clean, and clean the outer surface of the cooler if necessary ； 　 5) Check whether the environment has any impact on the air intake and exhaust of the unit. If so, the influence of external factors should be eliminated to ensure normal ventilation of the unit. ； 　 6) Check whether the temperature control valve is damaged ； Check whether the solenoid valve solenoid coil and solenoid valve diaphragm are damaged, repair or replace if necessary ； 　 7) Check whether the oil-gas separator filter element is clogged or has excessive resistance. If so, replace the oil filter element. 　 The compressor consumes a lot of oil: 1) Check whether the oil content of the condensed water discharged from the drain valve is large. If so, check the leakage point in the unit and eliminate it. ； 　 2) Check whether the compressor oil level is high. If it is high, lower the oil level. ； 　 3) Check whether the opening pressure of the pressure valve is normal. Check and replace the valve if necessary. ； 　 4) Check whether the oil return pipe is blocked. Clean or replace the oil return pipe if necessary. ； 　 5) Check whether the oil and gas separator filter element has failed and replace the oil separator filter element if necessary. 　 The compressor does not supply air: 1) Check whether the control cylinder operates and whether the butterfly valve has any mechanical failure. ； 　 2) Check whether the loaded electromagnetic coil has suction ； 　 3) Check the branch circuits where the solenoid valves are located one by one. 　 The compressor cannot start: 1) Check whether there is control voltage. If not, check whether the fuse, etc. are intact. ； 　 2) Check whether the control relay and time relay operate normally. 　 The compressor operates normally, but it is difficult to start after shutdown: 1) The lubricating oil used is of the wrong grade, and the oil should be changed thoroughly after cleaning. ； 　 2) The oil is sticky and coked, so it should be cleaned and completely changed. ； 　 3) The shaft seal is seriously leaking. Remove and replace it. ； 　 4) The original position of the unloading valve disc changes and the position is readjusted. 　 The compressor does not start smoothly and automatically stops after a few seconds of startup: 1) Check whether the automatic air switch jumps and whether the voltage is normal. This should be eliminated. ； 　 2) Check whether the intake butterfly valve is closed properly and need to be readjusted or replaced. ； 　 3) Check whether the contactor and the three phases of the motor are normal during Y-△ startup.