For mechanized construction enterprises, whether the technical condition of construction machinery is good or not is a direct factor for the normal production of enterprises. As far as hydraulic transmission engineering machinery is concerned, the normal operation of hydraulic system is a main symbol of its good technical condition. Qualified hydraulic oil is the guarantee of reliable operation of hydraulic system, and correct maintenance is the basis of reliable operation of hydraulic system. Therefore, according to the working practice, I make a rough discussion on the maintenance of hydraulic system of construction machinery in general working environment.
1) Choosing suitable hydraulic oil
Hydraulic oil plays the role of transmitting pressure, lubrication, cooling and sealing in hydraulic system. The main reason for early failure and durability decline of hydraulic system is improper selection of hydraulic oil. Hydraulic oils shall be selected according to the grades specified in the Random Instructions for Use. When substituted oils are needed in special cases, the performance of the hydraulic oils shall be the same as that of the original grades. Hydraulic oils of different grades can not be mixed to prevent chemical reaction and performance change of hydraulic oils. Dark brown, Milky white, odorous hydraulic oil is deteriorated oil, can not be used.
2) Preventing solid impurities from mixing into hydraulic system
Clean hydraulic oil is the life of hydraulic system. There are many precise couples in the hydraulic system, some with damping holes, some with cracks and so on. If solid impurities invade, it will cause precise couple parts to pull, hairpin, oil duct blockage and so on, endangering the safe operation of hydraulic system. Generally, the ways of solid impurities intruding into hydraulic system are: unclean hydraulic oil; unclean refueling tools; inadvertent refueling and maintenance; debris removal of hydraulic components, etc. The following aspects can be used to prevent solid impurities from intruding into the system:
3) Refueling Maintenance
Hydraulic oil must be filtered and filled, and filling tools should be reliable and clean. It is not possible to remove the filter at the filling port of the tank in order to improve the filling speed. Refuelers should use clean gloves and work clothes to prevent solid and fibre impurities from falling into the oil.
Removal of hydraulic tank filling cap, filter cap, detection hole, hydraulic tubing and other parts, resulting in system oil duct exposure to avoid dust, the removal part must be thoroughly cleaned before opening. If the hydraulic tank filling cap is disassembled, first remove the soil around the oil tank cap, screw loose the oil tank cap, and remove the debris remaining in the joint (water can not be washed to avoid water infiltration into the tank), and then open the oil tank cap after confirmation of cleanliness. When wiping materials and hammers are needed, special wiping materials and hammers that do not remove impurities from fibers should be selected. Hydraulic components and hoses should be carefully cleaned and assembled after being dried by high-pressure air. Choose the well-packed filter element (the inner packaging is damaged, although the filter element is intact, it may also be unclean). Clean the filter at the same time when changing oil. Before installing the filter element, clean the bottom dirt of the filter shell carefully with wiping material.
C. Cleaning of Hydraulic System
Cleaning oil must use hydraulic oil of the same brand as that used in the system. The oil temperature is between 45 ~80 C. The impurities in the system should be removed as far as possible with large flow rate. The hydraulic system should be cleaned more than three times. After each cleaning, all the hydraulic system should be released when the oil is hot. After cleaning, clean the filter, replace the new filter element and add new oil.