​Why is the hydraulic jack damaged and repaired

Hydraulic jacks are divided into general hydraulic jacks and special hydraulic jacks.General hydraulic jack is suitable for various lifting operations with small lifting height. It consists of oil chamber, oil pump, oil storage chamber, piston, rocker handle, oil valve, etc. When working, as long as the swing handle is switched back and forth, the manual oil pump keeps pressing oil into the cylinder. As the oil pressure in the cylinder keeps increasing, the piston and the weight above the piston will be forced to move upward together. When the return valve is opened, the high-pressure oil in the cylinder will flow back to the oil storage chamber, and the weight and the piston will fall together.            

The special hydraulic jack is a special tensioning machine, which exerts tension on the prestressing steel bar when making the prestressing concrete component. Most special hydraulic jacks  are double-acting. There are two commonly used types: piercing type and conical anchor type.            

 The piercing jack is suitable for tensioning steel bar or steel wire bundle. It mainly consists of tensioning cylinder, jacking cylinder, jacking piston and spring. Its characteristics are: along the axis of the stretcher, there is a perforation channel, and the steel bar (or steel wire) is anchored by the tool at the tail after penetration.            

 After discussing the classification of hydraulic jacks, we will specifically talk about the reasons for the failure of hydraulic jacks.            

 1.  For objects of comparative gravity, multiple jacks are required for lifting. The same type of hydraulic jack should be selected, and the sum of rated  lifting weights of each hydraulic jack should not be less than 1.5 times the weight of the equipment.            

 2.  Hydraulic Jack should be wiped clean before operation, and should check whether the components are sensitive and non-destructive. When there is load, do not unload the quick joint, so as to avoid accidents and damaged parts.            

 3.  Hydraulic Jack in the work, should first try to lift a part of the weight, carefully check the hydraulic jack is not exceptional, then continue to lift  the weight. If it is found that the cushion plate is not flat, unstable or the hydraulic jack is skewed after compression, the hydraulic jack must be relieved and returned to the journey, and can be operated again after being handled quickly.            

 Finally, we provide solutions.            

 Pressure is one of the two basic parameters of jack hydraulic system, which largely determines the performance of the hydraulic system. When adjusting the pressure of the jack hydraulic system, the system pressure can not be set up at all, and there is no pressure at all. Although the pressure can be adjusted up a little, it can not be adjusted to the highest level. Third, the pressure can not be adjusted down, always high pressure and other phenomena.            

 Self-examination method:           

 (1)  Check whether there is no flow output or not. If the rotation direction of the hydraulic pump is not right, it can be solved by the relevant knowledge of the hydraulic pump.            

 (2)  Check the fault of relief valve and other pressure regulating valve. For example, the relief valve core is stuck in the total overflow of the overflow position system, the unloading valve core is stuck in the total unloading of the unloading position system, and the system pressure can not go up.            

 (3)  Direction check control valve. The valve core of the reversing valve does not  move in place to cause the pressure oil chamber and the return oil chamber to  cross.            

 (4)  Check the actuator. The locking nut connecting the piston and piston rod of the hydraulic cylinder is loosened, and the piston runs out of the piston rod, which makes the two  chambers of the hydraulic cylinder communicate with each other.