Cleaning method of working volumes of hydraulic cylinders of agricultural machines without preliminary dismantling

Background. More and more often lifting equipment is equipped with a hydraulic drive, which allows to develop the highest tractive force. However, this type of drive is prone to a reduction in the speed of the mechanism due to possible clogging of the working fluid. The performance of the hydraulic system directly depends on the cleanliness of the working fluid, which is operated in the equipment or machine. Dirt, the presence of air, as well as the presence of metal particles formed as a result of rubbing parts, all this negatively affects the service life and reliability of the hydraulic system. The paper describes a bench method of cleaning the working volume of the hydraulic cylinder without preliminary dismantling. The principal hydraulic scheme with a detailed description of the washing system operation is offered. The possibility of dispersing the flushing fluid flow by air bubbles is described.

Purpose. The purpose of the research is a method of cleaning the working volumes of hydraulic cylinders of agricultural machines without preliminary dismantling

Materials and methods. In most cases, the hydraulic system is flushed with the help of special stands. The flushing stand itself is a rather complex system of interaction of hydraulic units

The design feature of the developed unit is the pressurized supply of a gas-liquid mixture. It consists of air bubbles and washing liquid.

For the formation of air bubbles in the liquid a cavitator is installed. The flushing liquid is fed to the cavitator due to the pressure generated on the surface of the flushing liquid by the compressor. In parallel from the compressor there is a branch with air to the cavitator. As a result, from the cavitator the gas-liquid mixture enters one of the cavities of the double-acting hydraulic cylinder. After the piston takes the opposite extreme position, the hydraulic valve is switched, and the gas-liquid mixture enters the next cavity. The process is then repeated. After the cavity has been cleaned, the contaminants are removed by draining with the spent flushing fluid.

Results. Flushing unit with the use of air bubbles significantly increases the viscosity of the flushing fluid, and this reduces the rate of settling only flushed contaminants in the cavity of the product, which improves the removal of contaminants through the spigots.

In particular, for the mentioned parameters of the cylinder gas bubbles should be the size of 5 mm, the speed of surfacing of which is 12.3 mm/s, which justifies the need to fill/empty the cavity of the hydraulic cylinder within 10 seconds, at the same time for flushing the hydraulic system create a flow of fluid with a Reynolds number of at least 4000, and the nominal pressure in the hydraulic cylinder is 18 MPa.

Conclusion. The developed basic hydraulic scheme and the proposed design of the flushing stand provide high efficiency of the cleaning process. In addition, the calculations and experiments confirm the correctness of the selected parameters and schemes, which makes this method promising for wide application in industry.