Hydraulic top is a relatively simple lifting machinery, lifting height is small, there are two kinds of machinery and oil pressure, mechanical hydraulic top has rack and pinion and screw two kinds, because of the lifting weight is small, the actual operation is difficult, generally only used for equipment maintenance work, not suitable for the whole bridge construction process. At the same time, we should pay attention to the application of vertical jack hydraulic oil, because the advantages and disadvantages of hydraulic oil can directly harm the hydraulic jack can work properly. Therefore, it is necessary to have better performance of hydraulic oil. In the hydraulic top, manual jack hydraulic oil should have the following roles:

1. The transmission system, namely, transfers the hydraulic piston rod in the top to the implementing element.

2. Lubrication, the piston rod, throttle valve, oil return valve stem and implementation components and other fitness sports components to carry out lubrication.

3. Digest and absorb and get the heat generated by the hydraulic control valve on the top of the hydraulic pressure.

4. Anti-rust treatment, avoid the hydraulic machine components in the top of the metal materials commonly used rust. ? In addition, the hydraulic oil must also have the following performance requirements for the work.

5. Compatibility. It has excellent compatibility with metal materials, hydraulic seals, high pressure hoses, architectural coatings, etc. ? Hydraulic jacking is widely used in power engineering maintenance, highway bridge overhaul, lifting lifting, foundation pile pressing, basic foundation settlement, highway bridge and ship construction, especially spiral jack in road construction and mechanical equipment adjustment, machine equipment disassembly and other levels. Because the main use of hydraulic press is universal, so the scope of itinerary is also more extensive.

The corresponding function information content must be paid attention to when selecting hydraulic oil of hydraulic jack