Generally, this phenomenon will occur when the air compressor intake valve is broken or the pressure maintenance valve is broken. In addition, this situation will also occur when the unloading valve is adjusted too large. So what exactly causes it? In fact, there are mainly the following reasons for the oil leakage from the air filter port of the screw air compressor:
1. Mainly due to abnormal shutdown, the unit is shut down with pressure, causing the intake valve to be closed in time or closed without sealing, and high-pressure oil and gas are ejected from the intake valve (such as power outage shutdown, emergency shutdown)
2. The intake valve balance hammer or the sealing surface of the one-way valve is dirty, and the sealing surface is damaged or stuck, which will also cause the air filter to return oil.
3. The exhaust oil content of the equipment is high. Some models that are discharged to the air filter have oil in the air filter gas from the self-discharge valve, resulting in oil in the air filter. At this time, the exhaust oil is often accompanied.
4. If the oil level in the oil and gas barrel is too high, when the temperature of the screw air compressor unit is too high, the shutdown relief valve is unloaded too quickly, and the high pressure emergency stop is due to high temperature and rapid pressure changes, if the screw oil bubbles, it will cause a large number of bubbles to flow into the oil separator, resulting in more oil in the discharge pipe, and it is also easy to form the phenomenon of oil return at the air filter port. At the same time, the exhaust gas contains a large amount of oil.