I. Air Flow 1. After dust is filtered out by the air filter, the air enters the main compression chamber through the intake valve and is compressed, mixing with lubricating oil. The compressed air mixed with oil is discharged to the oil-air separator, and then passes through the oil separator, pressure maintaining valve, and aftercooler before being sent to the operating system. 2. Functional Description of Components in the Main Air Source Path A. Air Filter The air filter is a dry paper filter with a filter paper pore size of approximately 5μm. Its main function is to filter out dust from the air, preventing premature wear of the screw rotor and premature clogging of the oil filter and oil separator. It should be removed and cleaned of surface dust every 500 hours of operation. The cleaning method is to use low-pressure air to blow the dust away from the inside out. B. Intake Valve The intake valve is a disc-type intake valve, mainly controlling the no-load and heavy-load operation by opening and closing the disc inside the intake valve. There are two control modes: one is an on/off type, where the intake port is closed when the pressure reaches the high limit setting value, and reopens for full-load operation when the pressure drops to the low limit setting value. Another type of capacity regulation control uses a partially closed intake valve disc in conjunction with a proportional valve to adjust the pressure according to the external air consumption, keeping it stable within a certain range. Before reaching the capacity regulation pressure, the intake valve disc is fully open, and the compressor operates at full load. The oil-gas separator has both oil-gas separation and oil storage functions. The compressed oil-gas mixture is discharged into the oil-gas separator, where rotation separates most of the lubricating oil. The separator stores a relatively large amount of lubricating oil, preventing the newly separated hot oil from immediately participating in the next cycle, thus helping to reduce exhaust temperature. An oil level indicator is installed on the side of the oil-gas separator. There is a filler hole on the separator for adding oil; the static lubricating oil level should be between the upper and lower limits of the level gauge. A drain (water) ball valve is installed at the bottom of the oil-gas separator. This valve should be slightly opened before each operation to drain condensate (as water is heavier than oil and settles at the bottom). Once oil flows out, the valve should be closed immediately. Due to the large cross-sectional area of ​​the oil-gas separator, the compressed air velocity is reduced, which is beneficial for oil droplet separation and plays a preliminary role in oil removal. The "Lubricating Oil Flow" section of the D oil-fine separator provides a detailed explanation, which is omitted here. The E safety valve automatically activates and releases pressure when the gas pressure inside the oil-gas separator exceeds 1.1 times the rated discharge pressure, reducing the pressure below the rated discharge pressure. To check the safety valve, gently pull the vent lever on the safety valve while the compressor is operating at full load. If the safety valve can release gas, it is considered normal. The F minimum pressure valve is located at the outlet of the oil-fine separator above the oil-gas separator. The opening pressure is set to approximately 0.45 MPa. The minimum pressure valve mainly has the following functions: a. Prioritizes establishing the required circulating pressure for lubricating oil during startup to ensure machine lubrication. b. Opens only after the gas pressure in the oil-gas separator exceeds 0.4 MPa, reducing the air velocity flowing through the oil-fine separator. This ensures effective oil-fine separation and protects the oil-fine separator from damage due to excessive pressure difference. c. Backflow function: Prevents compressed air from flowing back into the pipeline when the pressure inside the oil-gas separator drops after shutdown. G. Compressed air flowing from the minimum pressure valve to the aftercooler. The aftercooler and oil cooler are integrated and have the same structure, both being plate-type. The cooling fan draws in cold air and blows it over the aftercooler's plate. The temperature of the cooled compressed air is generally below ambient temperature +15℃. II. Lubricating oil flow 1. Lubricating oil flow description The pressure inside the oil-gas separator forces the lubricating oil out of the separator. After passing through the oil cooler and oil filter to remove impurities, the oil is divided into two paths. One path is sprayed into the compression chamber from the bottom of the machine body to cool the compressed gas; the other path goes to both ends of the machine body to lubricate the bearing assembly. The lubricating oil from each part then gathers at the bottom of the compression chamber and is discharged from the exhaust port. After the compressed air mixed with oil is discharged into the oil-gas separator, most of the oil settles at the bottom of the separator. The remaining oil-mist air then passes through the oil separator to further filter out the remaining oil and participates in the next cycle. 2. Oil Injection Control: The oil injected into the air compressor serves a lubricating function and primarily removes heat generated during air compression. The injection quantity is pre-set by our technicians before leaving the factory; therefore, please do not change it arbitrarily. 3. Functional Description of Main Oil Circuit Components: A. Thermostatic Valve: The main function of the thermostatic valve is to control the exhaust temperature of the compressor by controlling the humidity of the lubricating oil injected into the compressor head, thus preventing moisture in the air from condensing and emulsifying the lubricating oil in the oil-gas separator. When the machine is first started, the lubricating oil temperature is low, and the thermostatic valve is closed, allowing cold oil to be injected directly into the machine without passing through the cooler. If the oil temperature rises above 70℃, the thermostatic valve gradually opens to the oil cooler passage, fully opening at 76℃. At this point, the oil will be completely cooled by the oil cooler before being injected into the machine. Some models do not have a thermostatic valve; instead, the oil temperature is controlled by stopping or stopping the fan motor. When the exhaust temperature rises to 85℃, the fan starts running; when the exhaust temperature is below 75℃, the fan automatically stops, maintaining the temperature within a certain range. B. Oil Cooler: The oil cooler and aftercooler are integrated. C. Oil Filter: The oil filter is a paper filter with a filtration accuracy between 10μm and 15μm. Its function is to remove impurities from the oil, such as metal particles, dust, and oil deterioration products, protecting the bearings and rotor for normal operation. If the oil filter is clogged, it may lead to insufficient oil injection, affecting the service life of the main bearings and causing the exhaust temperature of the compressor head to rise (or even shut down). D. Oil Separator: The oil separator filter element is made of multiple layers of fine special fibers. The mist-like lubricating oil contained in the compressed air can be almost completely filtered out after passing through the oil separator. The oil particle size can be controlled to below 0.1μm, and the oil content can be less than 3PPM. E. Return Oil Check Valve: The residual oil filtered by the oil separator is concentrated in the small round groove in the center of the filter element and led to the main unit through the return oil pipe, preventing the separated lubricating oil from being discharged with the air again. To prevent oil backflow in the main unit's compression chamber, a check valve is installed after the return oil pipe. If the oil consumption suddenly increases during machine operation, check whether the throttling orifice of the check valve is blocked. III. Air Circuit Control Components A. Loading Solenoid Valve: This is a two-position, normally closed solenoid valve. The energization and de-energization of the solenoid valve control the on/off state of the air circuit, achieving loading and unloading functions. B. Vent Valve: This valve opens during unloading operation or shutdown, releasing pressure in the oil-gas tank, allowing the compressor to operate at low load, or ensuring restarting under no-load conditions. C. Inverse Proportional Valve: This valve only activates above the set regulating pressure. At this point, the higher the proportional valve (i.e., the system's exhaust pressure), the lower the output control pressure. The lower the control pressure, the smaller the opening of the intake unloading valve disc controlled by the cylinder's extension and retraction, resulting in a smaller intake volume for the compressor. This balances the compressor's air supply and consumption, achieving stepless air volume regulation. The method for setting the regulating pressure is: lift the black cap of the inverse proportional valve upwards and rotate it. Clockwise rotation increases the pressure, and counterclockwise rotation decreases it. After setting, press the cap down to prevent it from rotating due to vibration. The set value should generally be lower than the rated exhaust pressure. If it is higher than the unloading pressure set by the microcomputer controller, there will only be empty and loaded vehicles without capacity adjustment. D. Sensors: Pressure and temperature sensors measure various parameters to enable compressor loading/unloading, various fault prompts, and automatic shutdown when necessary.