Function description and maintenance method of each component on the main air supply channel
1. Air filter
The air filter is a dry paper filter with a fine porosity of about 5 μ M or so. Its main function is to filter the dust in the air to avoid premature wear of the screw rotor and premature blockage of the oil filter and oil fine separator. Generally, every 500 hours of operation, remove the dust on its surface. The method of cleaning is to use low-pressure air to blow the dust from the inside out.
Maintenance method of air filter:
The air filter should be serviced once a week. Unscrew the gland nut, take out the air filter element, use 0.2-0.4Mpa compressed air, blow out the dust particles on the outer surface of the air filter element from the inner chamber of the air filter element, clean the dirt on the inner wall of the air filter housing with a clean cloth, reinstall the air filter element, and pay attention to that the sealing ring at the front end of the air filter element is closely attached to the inner end of the air filter housing. Heavy duty air filter can be opened directly, and the maintenance method is the same as above.
Under normal circumstances, the air filter should be replaced every 1500-2000 hours. In places where the environment is particularly harsh, such as mines, ceramics factories, cotton mills, etc., it is recommended to replace the air filter element every 500 hours. Please use genuine filter when replacing.
When cleaning or replacing the air filter, the components must be matched one by one to prevent foreign matters from falling into the inlet valve.
At ordinary times, always check whether the air inlet expansion pipe is damaged or flat, and whether the connection port between the expansion pipe and the air inlet valve of the air filter is loose or leaking. If any, it shall be repaired and replaced in time.
2. Inlet valve
The air inlet valve is a disc type air inlet valve, which controls the empty and heavy load mainly by opening and closing the discs in the air inlet valve; There are two control methods, one is switch type. When the pressure reaches the high limit setting value, close the air inlet, and when the pressure drops to the low limit setting value, reopen the air inlet for full load operation. Another type of capacity regulation control is that the disc of the inlet valve is slightly closed and the proportional valve is used for capacity regulation control to adapt to the external air consumption and stabilize the pressure within a certain range. If the pressure does not reach the capacity regulation pressure, the disc of the inlet valve is fully opened. At this time, the compressor operates under full load.
Maintenance method of inlet valve:
The fault of the air valve is that the screw machine does not unload and the inlet valve is not closed. The solenoid valve of the intake valve is damaged if it is not loaded. Screw engine oil injection, valve control block fault. The screw machine is overloaded, and the inlet valve is opened in advance when starting. Therefore, the air inlet control valve should be replaced with a repair kit regularly to maintain a good working condition. During each maintenance, the parts must be removed to check the wear of each friction surface, especially the rubber seal ring surface. If there is damage or crack, the new parts must be replaced. After the repair kit is replaced, all parts should be cleaned, and the friction surface of metal parts should be coated with lubricating oil.
3. Oil and gas barrel
Oil and gas barrel has two functions of oil and gas separation and oil storage. The compressed oil and gas mixture is discharged to the oil and gas barrel, and most of the lubricating oil can be separated by rotating in the oil and gas barrel; There is more lubricating oil in the oil and gas tank to prevent the hot oil just separated from participating in the next cycle immediately, which is conducive to reducing the exhaust temperature. An oil level indicator is installed on the side of the oil and gas tank. There is a filler hole on the barrel for refueling. The level of static lubricating oil should be between the upper and lower limits of the oil level gauge. The oil (water) drain ball valve is installed below the oil and gas drum. The ball valve should be slightly opened before each operation to drain the condensate in the oil and gas drum (because the water is heavier than the oil, it settles in the lower part). Once oil flows out, close it quickly. Due to the wide sectional area of the oil and gas barrel, the flow rate of compressed air can be reduced, which is conducive to the separation of oil droplets and plays the role of preliminary oil removal.
4. Safety valve
When the gas pressure in the oil and gas drum is 1.1 times higher than the rated exhaust pressure, the safety valve will automatically jump to relieve the pressure, reducing the pressure below the rated exhaust pressure. The method to check the safety valve is to gently pull the air release rod on the safety valve when the compressor is working with full load. If the safety valve can exhaust, it is considered normal.
Maintenance method of safety valve:
In order to ensure that the performance of the safety valve of the air compressor will not change, the safety valve of the air compressor must be regularly protected and cleaned to prevent the ash layer, water vapor, dirt, etc. from entering the valve body and affecting the performance of the valve body.
Monthly maintenance items
The safety valve of the air compressor needs to be maintained every month, and the maintenance personnel must be professional. Otherwise, the valve body will have problems during maintenance. The monthly maintenance includes the cleaning of oil filter and oil-gas separator, and the cleaning of air filter. The cooling equipment also needs to be lubricated, and all parts of the pump body should be checked to eliminate potential safety hazards, and the valve body should be cleaned.
Annual maintenance items
The annual maintenance item is the most important one among the air compressor safety valves, which is different from the monthly maintenance, and the inspection is more extensive. As for the annual maintenance items, it is necessary to clean the oil and water vapor lines, and adjust each component of the valve body to check whether there is a problem. If there is a problem, it needs to be replaced in time.
5. Minimum pressure valve
It is located at the outlet of the oil fine separator above the oil and gas drum. The opening pressure is set to about 0.45MPa. The minimum pressure valve mainly has the following functions:
Priority shall be given to establishing the circulating pressure required by the lubricating oil when starting to ensure the lubrication of the machine.
The oil and gas drum can be opened only after the gas pressure exceeds 0.4 MPa, which can reduce the air flow rate through the oil fine separator. In addition to ensuring the oil fine separation effect, it can also protect the oil fine separator from damage due to too large pressure difference.
To return function: when the pressure in the oil and gas drum drops after shutdown, prevent the return of compressed air in the pipeline.
Maintenance method of minimum pressure valve:
The valve cover temperature detection shall be checked on schedule, the minimum pressure valve cover surface temperature shall be recorded, and the chart shall be made for recording. Combined with the instrument detection equipment operating parameters (such as temperature and pressure), the minimum pressure valve operating condition shall be analyzed according to the recorded temperature changes, the service life shall be predicted, and the maintenance time shall be arranged reasonably.
The minimum pressure valve operation sound detection uses a stethoscope and other tools to monitor the movement sound of the minimum pressure valve blade and compare it with the valve of the same name at the same level. It is very easy to identify the minimum pressure valve that is not working normally, and maintenance can be arranged accordingly.
Analyze changes in process parameters. Once the minimum pressure valve leaks, it will cause changes in temperature, pressure or flow. Through the change of these parameters, it can be analyzed which level of the minimum pressure valve or even which minimum pressure valve has faults.
6. Aftercooler
Compressed air from the minimum pressure valve flows to the aftercooler. The aftercooler and oil cooler are made into a whole with the same structure, both of which are of the plate warping type. The cooling fan draws in cold air to blow the rocker of the aftercooler. The temperature of the cooled compressed air is generally below the ambient temperature+15 ℃.
Maintenance method of aftercooler:
The cooler shall be cleaned regularly according to the environmental conditions, so that the compressor can work at normal temperature to ensure a long service life of the machine. When the cooler is dirty and blocked, the compressor exhaust temperature will rise. Generally, clean the outside of the air-cooled cooler every 1500 hours, and clean the water side of the water-cooled cooler every 1500 hours. Regular cleaning of the cooler has the following advantages:
It is good for the performance and service life of the machine to keep the unit working at the ideal working temperature (below 95 ℃).
The dirt can be removed by using cleaning fluid, otherwise, when the dirt is thick, the cleaning work is rather troublesome, and the cooler needs to be disassembled to complete the cleaning work with mechanical methods.

Function description of main components of the second oil circuit
1. Temperature control valve
The main function of the temperature control valve is to control the exhaust temperature of the compressor by controlling the humidity of the lubricating oil sprayed into the head, so as to avoid the water vapor in the air from condensing in the oil and gas barrel and emulsifying the lubricating oil. When the machine is just started, the lubricating oil temperature is low, the temperature control valve is closed, and the cold oil is directly injected into the machine body without passing through the cooler. If the oil temperature rises above 70 ℃, the temperature control valve will gradually open the channel to the oil cooler. When the temperature reaches 76 ℃, it will be fully opened. At this time, all the oil will be cooled by the oil cooler and then injected into the machine body Some models do not have temperature control valves, but control the oil temperature by controlling the stop of the fan motor. When the exhaust temperature rises to 85 ℃, the fan starts to run; When the exhaust temperature is lower than 75 ℃, the fan will stop automatically to keep the temperature within a certain range.
Maintenance method of temperature control valve
Disassembly of temperature control valve: there is a cover on the side of the temperature control valve of the screw air compressor, and there is a screw hole on the cover. Find a suitable nut to screw in the cover, and then use the circlip pliers to take out the circlip fixing the cover. Then use the pliers to pull the nut just screwed in, and you can take down the cover and all internal parts.
Cleaning temperature control valve: Soap water, diesel oil, clean gasoline, Tianna water, etc. shall be used as the cleaning agent. The above cleaning agents shall be selected according to the degree of dirt. Soap water or diesel oil is generally recommended for cleaning. If the dirt of the temperature control valve is serious, replace it with a new detergent.
2. Oil cooler
The oil cooler is integrated with the aftercooler.
3. Oil filter
The oil filter is a paper filter with a filtering accuracy of 10 μ~ fifteen μ between. Its function is to remove impurities in the oil. Such as metal particles, dust, oil deterioration, etc., to protect the normal operation of bearings and rotors. If the oil filter is blocked, it may lead to insufficient fuel injection, which will affect the service life of the main engine bearing, and the exhaust temperature of the machine head will increase (or even stop).
Maintenance method of oil filter
Every 100h or within a week when the drilling rig works: the primary filter screen of the oil filter and the coarse filter screen on the oil tank must be cleaned. During cleaning, remove the filter element and use a wire brush to remove the dirt on the screen. Since the air compressor works in a dusty environment, it is important to clean the air filter and oil filter frequently. Ignoring this will cause a series of failures.
Every 300h: clean the filter core, blow it dry after cleaning, and then soak the same oil in the oil tank. If the dust is very serious, determine the cleaning cycle according to the actual situation. When the red line of the air pollution indicator on the unloading valve can be seen, it indicates that the air filter is seriously polluted, and the air filter should be cleaned. Clean or check the unloading valve, minimum pressure valve, automatic vent valve and other parts. Thoroughly clean the oil filter and clean the dirt deposited at the bottom of the oil filter.
Replace the paper filter element of oil filter every 1000h. Check whether the safety valve, temperature control valve, pressure regulator and pressure regulating valve work normally.
Every 3000h: check the oil pump, check or replace the seal ring. According to the emulsification degree of the base oil, the number of impurities and the change of viscosity, replace the new oil as appropriate. The filter element of oil separator can normally be used for 2000~4000h. No special maintenance is required during this period. If the compressor oil consumption increases significantly, check or replace the core, unscrew the two M24 on the exhaust seat × 1.5. Check the clearance of the exhaust valve and adjust it as appropriate. When it is used in a dusty environment, the dust is easy to accumulate on the oil cooler and the cooling effect deteriorates. It should be cleaned according to the specific situation. Generally, it is required to clean once every 4 months to ensure the heat dissipation effect.
4. Oil fine separator
The filter element of the oil fine separator is made of multi-layer fine and dense special fibers. The mist like lubricating oil contained in the compressed air can be almost completely filtered off after passing through the oil fine separator, and the oil particle size can be controlled at 0.1 μ Below m, the oil content can be less than 3PPM.
Maintenance method of oil fine separator
The oil-gas separator will generally cause blockage failure. If the oil-gas filter is found to be blocked, it may be caused by the following reasons:
Check the surroundings of the press. Whether there is corrosive gas, such as sulfide, Tianna water, cleaning chemicals, etc. volatilized in the air in some occasions. Or whether the air compressor temperature is too high.
Use qualified air filter, oil filter and engine oil. Change the engine oil and filter element timely.
Check whether there is any leakage on the pipeline between the air filter and the air inlet of the main engine. Common causes of leakage include: the air filter is not installed properly; The contact area of the air filter assembly is uneven; The contact surface between the air filter and the assembly has dirt attached to it, causing leakage; The elastic contact pad on the surface of the air filter is placed askew; The air filter or air filter assembly is broken.
Check whether there is too much water on the oil separation filter material to prevent the oil separation resistance from increasing and blocking in advance.
5. Oil return check valve
The residual oil filtered by the fine oil separator is concentrated in the small round groove in the center of the filter element and led to the main engine through the oil return pipe to prevent the separated lubricating oil from being discharged with air. To prevent oil backflow in the compressor chamber of the main engine, a one-way valve is set behind the oil return pipe. If the oil consumption suddenly increases during the operation of the machine, check whether the orifice of the one-way valve is blocked.
Maintenance method of oil return check valve:
Disassembly of oil return single valve: there is a connection in the valve body, unscrew it from there and take out the spring, steel ball and steel ball seat.
Clean the oil return check valve: clean the valve body, spring, steel ball, and steel ball seat with cleaning agent. Some check valves have filter screens inside. If any, clean them together.
Three air circuit control components
1. Loading solenoid valve
It is a two position two normally closed solenoid valve. Through the power on and power off of the solenoid valve, the on-off state of the air circuit is controlled to realize the loading and unloading functions.
2. Vent valve
When unloading operation or shutdown, this valve will open to release the pressure in the oil and gas drum, so that the compressor can operate at low load or restart under no load.
3. Inverse proportional valve
Only when the set regulating pressure is exceeded, the higher the proportional valve (i.e. the exhaust pressure of the system) is, the lower the output control pressure will be. The lower the control pressure is, the smaller the opening of the air inlet unloading valve disc controlled by the cylinder expansion and contraction is, and the smaller the air intake volume of the compressor is, so that the air supply volume and the air consumption volume of the compressor are balanced, and the stepless air volume regulation function is realized. The method for setting and adjusting the pressure is: lift up the black cap of the inverse proportional valve and rotate it. If it rotates clockwise, the pressure will increase, and if it rotates counterclockwise, the pressure will decrease. After setting, press down the cap to prevent it from rotating due to vibration. The set value shall generally be less than the rated exhaust pressure. If it is higher than the unloading pressure set by the microcomputer controller, there will be only empty and loaded vehicles without capacity adjustment.
4. Sensor
The pressure and temperature sensors can measure various parameters to realize the loading and unloading of screw air compressor, various fault prompts, and automatic shutdown when necessary.