290HC Mast Section Fault analysis, detection, maintenance and repair of hydraulic jacking system of tower crane
The function of hydraulic lifting system of tower crane
290HC Mast Section：
http://www.towercranesupply.com/product/290hc-mast-section-liebherr-tower-crane
The hydraulic jacking system of tower crane can increase or decrease the standard section by jacking and lowering the tower crane frame, so that the tower crane can increase or decrease with the change of building height, so as to meet the vertical transportation needs of buildings with different heights. The system is mainly composed of hydraulic pump station, hydraulic jacking oil cylinder, lock valve and high-pressure hose. During the jacking operation of tower crane, the system needs to bear more than 30 tons of weight of the upper structure of tower crane, and the working pressure of the system reaches more than 18 MPa, which belongs to high-pressure hydraulic system. The system has the advantages of small size, light weight, high specific power, stable operation, etc., but at the same time, it has the defects of low transmission efficiency, easy to produce faults and so on. Because the hydraulic jacking system of tower crane belongs to the pipeline circulation system with seal and pressure, the flow of oil in the pipeline, the movement of parts inside the hydraulic components and whether the seal is damaged are not easy to detect, so it is difficult to analyze the cause of the fault and judge the location of the fault.
Fault analysis of hydraulic jacking system of tower crane
Half of tower crane accidents are caused by improper handling after system failure. In order to avoid major equipment accidents, how to prevent hydraulic jacking system failure has become an urgent problem to be solved. Through the comprehensive statistics of the faults of the hydraulic jacking system, it is found that most of the system faults are sudden faults and wear faults, and the main cause of these faults is the pollution of the hydraulic oil.
290HC Mast Section：
http://www.towercranesupply.com/product/290hc-mast-section-liebherr-tower-crane
The main causes of hydraulic oil pollution are water, dust, air, etc. mixed in the use and maintenance of hydraulic oil; metal scraps, sand and other impurities remained in the system in the manufacturing process of hydraulic components; metal abrasive particles caused by wear of hydraulic components in use and rust produced by oil tank.
The hydraulic jacking system is a closed circulation system. After the hydraulic oil is polluted, when it passes through the gear pump, the hard granular dirt will increase the wear of the relative sliding parts. The metal scraps generated by the wear will enter the oil tank with the return oil of the system. With the continuous circulation of the oil, more and more dirt will enter the pump, and the particle size of the dirt will be finer and finer, which will bring more and more wear to the hydraulic components The more serious the gap between the moving parts is, the more internal leakage will occur, which will reduce the working efficiency of the system and increase the oil temperature.
The hydraulic oil is the power transmission medium of the hydraulic jacking system, which is easy to oxidize and deteriorate after being affected by temperature, pressure and pollution. Once the hydraulic oil oxidizes and deteriorates, it not only reduces the compatibility between the seal and the oil, accelerates its aging, and loses its sealing performance; moreover, the oil film does not play a lubricating role after oxidization, making the metal surfaces of the relative moving parts contact each other, accelerating the metal surface of the parts Wear, the final internal leakage makes the working efficiency of the system decline, unable to reach the working pressure.
In addition, the overflow valve, lock valve and other components in the hydraulic jacking system are all operated by the oil pressure control. Once the dirt is stuck between the valve core and the valve body or the valve core damping hole is blocked, the valve will not operate properly and cause the system to fail suddenly.
To prevent the hydraulic oil from being polluted is the key to prevent the hydraulic jacking system from failure
Therefore, in order to cut off the way of pollution, the first thing is to control the water in the hydraulic tank. Through years of observation, although the hydraulic pump station is equipped with rainproof device, the rainwater still penetrates into the oil tank through bolt holes, motor connection parts, etc. after a long time of use; therefore, it is necessary to seal these parts that are easy to water in the form of combined gasket, special sealant, etc., and repair the damaged rainproof device in time; each system should be discharged from the bottom of the oil tank before work Separated water. Control the quality of hydraulic oil.
In addition to regularly changing the required hydraulic oil according to the requirements of the use, it is necessary to check the quality of the hydraulic oil regularly. If the oil droplets, bubbles or milky white are found in the oil, it is necessary to change the hydraulic oil in time, including the remaining oil in the hydraulic cylinder, so as to avoid duplication of pollution. When adding hydraulic oil, it must be strictly filtered, and the appliance should be kept clean to avoid fine particles entering. Into the hydraulic system.
290HC Mast Section：
http://www.towercranesupply.com/product/290hc-mast-section-liebherr-tower-crane
