Excavator hydraulic system of the main components are: double piston pump, gear pump, control valve, rotary motor, travel motor, high pressure pipe, hydraulic cylinder. When the system after the initial operation of the assembly, the high pressure hydraulic oil will rinse the parts of the cavity, will be attached to the cavity of the pollutants washed into the hydraulic oil, resulting in hydraulic cylinder scratches, hydraulic components malfunction.

The excavator will be filled with gas in the components of the hydraulic system before the initial run. When the machine moves, the system in the oil pressure, the pipeline sealed gas and work, so that the gas temperature suddenly increased, resulting in: hydraulic oil oxidation deterioration; burn the seal and lead to leakage; Of the sealing device hardness becomes high, scratch the hydraulic cylinder; burned the piston rod and so on.

Since most of the manufacturing enterprises are working in an open environment, the concentration of solid dust particles in the environment is large and inevitably enters the hydraulic system, resulting in contamination of the hydraulic system.

Through the above analysis can be seen in the machine before the initial operation of the hydraulic system cleaning work is very necessary. Here are two kinds of purification program.

(1) external purification

The two high-pressure hoses that connect the bucket cylinder are connected to the A and B ends of the external cleaning device, respectively. When the "cylinder is extended" is operated, the main pump is operated from the main pump The hydraulic oil through the control valve, high-pressure pipeline, the system of pollutants, gas into the A-end, after the filter b on the solid contaminant purification, through a through the B-side into the oil return line back to the tank, to achieve When the "cylinder shrinkage" is operated, the hydraulic oil pumped from the main pump is controlled by the control valve and the high-pressure pipeline, and all the pollutants and gases in the system are brought into the B-end. After passing through the filter element C purification of solid contaminants, through the A end into the oil return line back to the tank, to achieve the system pipeline gas emissions. So repeatedly manipulate the bucket cylinder 3 ~ 5min, you can make the hydraulic oil itself and the hydraulic components of the remaining solid pollutants in the access to the cylinder before the purification. At the same time, the closed gas in the high-pressure line is circulated outside the system after several cycles of access to the hydraulic cylinder so that the solid contaminants and gases present in the system can be maximized before the pipe is connected to the hydraulic cylinder Purify. After the operation is completed, remove the purification device, then return to the original hydraulic cylinder of the pipeline, then the hydraulic cylinder to 80% of the trip to run 5 to 8 times.

The advantage of this scheme is that the solid contaminants in the system are filtered through the filter in the external purification device and can be effectively discharged outside the hydraulic system. The disadvantage is that special external cleaning equipment is required.

(2) own purification

Still bucket cylinder as an example. Connect the two ends of a high-pressure hose to the two high-pressure hoses connecting the bucket cylinder. When the operation of the "cylinder out", the fuel tank in the oil by the oil filter, the main pump into the oil filter, the pilot oil filter into the main pump; from the main pump out of the hydraulic oil by the control valve, The high-pressure hose flows into the tank through the oil in the oil return line, so that the contaminants entering the tank are filtered by the oil filter and the system is purified. When the "cylinder is shrunk", the system is also purified. So repeatedly manipulate the bucket cylinder 3 ~ 5min, so that the hydraulic oil itself and the hydraulic components of the remaining solid pollutants in the access to the hydraulic cylinder before the multiple purification; the same time, high-pressure pipeline closed gas After repeated cycles before the access to the hydraulic cylinder has been discharged from the system, the system exists in the solid pollutants and gases in the pipeline access to the hydraulic cylinder before the maximum degree of purification.

The advantage of this scheme is that there is no need to make a special purification device. The disadvantage is that the remaining solid contaminants in the system remain in the tank after filtration through the oil filter.

In the process of purification operation must pay attention to: After the purification work is completed, the hydraulic cylinder should be the first pressure relief and then remove the purification device; operators need to wear rubber gloves.