In the excavator brake air circuit system, a gas control valve is installed between the air pump and the air reservoir. Its main function is to separate oil and water from compressed air. Filter the dust and impurities in the compressed air. Prevent the compressed air in the air reservoir from flowing back to the air pump. During the use of the excavator, abnormal adjustment air pressure and other faults may occur, which will eventually lead to the failure of the gas control valve. This article will explain the causes of abnormal adjustment air pressure. Due to different models of excavators, the air pressure in the air reservoir of excavators may be different. Therefore, the data mentioned in the article are for reference only. Please refer to the specific value provided by the manufacturer.
If the gas pressure in the air reservoir reaches 0.637MPa during normal operation, the pressure in the air reservoir will not increase after pressure relief. When the air pressure in the air reservoir is lower than 0.49MPa, the pressure shall not be relieved. The air pressure can be adjusted by adjusting the screw to change the compression force of the large spring. If the air pressure is still abnormal after adjustment, there are two cases. First, the air pressure has exceeded the standard, but the pressure has not been released. At this time, consider whether the exhaust piston is blocked. If the O-ring outside the piston is too tight, and the lower spring of the exhaust piston is too hard, so that the normal pressure gas cannot drive the piston to operate. Grind the outer ring of the seal ring evenly or adjust and replace the spring. If the small spring inside the pressure regulating valve is compressed too tightly, it is difficult to push the thimble, and the axial hole of the plug is blocked, the air pressure can not be unloaded. The second is that the exhaust and pressure relief are started before the pressure reaches the requirements. The causes include air leakage of the pressure regulating film and too loose or even broken small spring in the pressure regulating valve. Or the thimble can be pushed under low air pressure, which makes the small hole on the pressure regulating valve housing leak continuously, causing the system air pressure to not rise. In this case, remove the adjusting screw on the valve first. Adjust or replace the small spring first, and then adjust the large spring.
