After working for a period of time, the FD50 forklift produced by our company, when the working device is loaded down, hydraulic oil is often sprayed from the tank breather, accompanied by the sound of steam spraying out.
This type of forklift hydraulic oil tank is an open structure that is commonly used in the industry. The gas in the oil tank communicates with the atmosphere through the respirator. When the oil is returned to the oil return pipe, the excess air in the tank is discharged through the respirator. Preliminary analysis of the reason for the fuel injection is that the ventilator has insufficient ventilation, but after removing the ventilator for a period of time, the problem still exists. Remove the fuel cap to test, after working for a period of time, the hydraulic oil is sprayed directly from the fuel cap.
The structure of the original hydraulic oil tank of this type of forklift is shown in the figure (a). The brake pump, steering gear, multi-way valve and mast cylinder oil return pipe port are arranged above the hydraulic oil level, and the pipe port is directly facing the steel oil suction pipe. On-site observation found that when the loading of the working device dropped, a large amount of oil quickly returned to the oil, and after passing through the port of the oil return pipe, it was quickly sprayed to the oil suction pipe, forming a fierce splash. After the temperature of the hydraulic oil increases, a large amount of oil droplets and oil mist will also be generated in the oil tank, causing the air pressure in the oil tank to rise sharply. These oils, oil droplets and oil mist are eventually discharged through the respirator. Due to the blocking effect of the filter screen, oil droplets and oil mist accumulate on the filter screen as they pass through the respirator. Under the effect of the pressure difference between the inside and outside of the oil tank, hydraulic oil is ejected from the respirator at high speed.
Because the above problems exist in the hydraulic oil tank, after research, we decided to re-arrange the position of the return pipe on the hydraulic oil tank. The structure of the improved hydraulic oil tank is shown in the figure (b). The specific method is as follows: the brake oil return pipe, steering gear return pipe and multi-way valve return pipe with frequent oil return are all arranged below the hydraulic oil level The positions of the oil return port and the oil suction pipe are staggered from each other, and the distance between the oil return port and the respirator should be increased as much as possible.
After re-arranging the above-mentioned oil return pipe of this type of forklift, the three oil return ports with frequent oil return are below the liquid level, which avoids the occurrence of oil droplets or oil mist caused by high-speed oil return impact on the oil suction pipe, and the fuel tank breather spraying phenomenon disappears. In addition, this improvement also plays a certain role in protecting the hydraulic components, and can also extend the service life of hydraulic oil.
