Analysis of main factors causing low air pressure in driving room of hydraulic excavator

The main factors causing low air pressure in the cab of hydraulic excavators can be classified into two aspects: indoor air leakage and interior leakage.

Leakage Lotion

In the past, when searching for the air dew point in the cab, the method of touching by hand was used to determine the leak point by feeling the air flow. This method is difficult to detect all leakage points, and can not visually evaluate the leakage of air leakage points. In this paper, smoke test method is used to find the leak point, that is, smoke is generated in the driver's cabin by using a smoke generator. The leakage of smoke is observed to find the air leakage point of the cab. Upon examination, the detailed locations of the main leak points include:

(1) special-shaped steel pipe leakage. The cab adopts the inner frame and outer skin structure, and the front frame adopts the special steel tube structure. Because the special-shaped steel pipe is provided with a technological hole, and the two ends are not sealed, a large amount of air is leaked from the lower part of the special-shaped steel tube and the hoisting hole at the top of the cab.

(2) the door side door and door frame are not sealed properly (big crack at the door). In the smoke test process, it is obvious that a large amount of smoke is leaking from the cab door and door frame, especially in the upper and lower corners of the cab side door.

(3) the hydraulic pilot pipe and the electric harness have the same sealing property as the through wire hole. Hydraulic cab first conduit and electrical harness need through the line hole on the floor with the other parts of the wheelhouse is due to pipeline and wire harness using only simple binding form, no sealing measures, resulting in a large number of smoke from between the pipeline and the wire through hole leakage.

Internal leakage

(1) another major factor that affects the supercharging capacity of the cab is the internal leakage in the cab. In the cause of the search process, found that, even if all the leaking leak point, and in the case of smoke leakage outside observation, driving room pressure is only about 50Pa. Further examination showed that, in the cab of the left rear has a leak in the cab by the blower, the air inside the suction and after air conditioning duct into the cab, which leads to the actual amount of air into the outside of the cab is greatly reduced, resulting in driving indoor air pressure is insufficient.

(2) the air duct is not sealed properly with the cab's skin, which results in the inner circulation at the entrance of the air duct. The structure of Chinese and foreign circulating air filter pressure in the air duct, the air duct in the compression process leading to the same cab skin cracks, which led to the cab internal exhaust air is inhaled again cab phenomenon (leakage).