The prestressed concrete slabs used jacks are usually used to the construction of bridge and buildings, railway and subway, water conservancy and hydropower engineering and It is suitable for the tension of group anchors with 1860-2000 sizes, Φ15.24, Φ12.7 strands. The YDC prestressed concrete slabs used jack is most popular mode in our company, are the upgrades of the primary jacks.
Using the new seals, to synchronous strengthen the seal-ability under great pressure. Using special alloy steel with heat treatment process, reducing the cylinder's expansion ratio in the tensioning process. So that the life of seals and sealing performance can be improved about 20%. In the word, the YDC series prestressed jack and pump' performance is improved, and widely used in pre-stressing and post stressing construction.
prestressed jack and pump also called post tension stressing cylinder, it is mainly used for stressing multi-strands prestressed anchors. It also can be used for pushing or pulling. This hydraulic cylinder matched with other accessories, used for tension wedges anchor, thread rebar, anchor rod on bridge, and hydropower engineering.  
Prestressed jack and pump structure and characteristics as following:
1. Adopt new sealing elements to enhance the sealing strength of the hydraulic cylinder block synchronously under high pressure;
2. Adopt special alloy steel hydraulic cylinder body material with heat treatment technology to reduce the expansion ratio of cylinder body in the process of tensioning, so as to improve the life and sealing performance of seals by about 20%;
3. In view of the problem that the jack is liable to damage the jack due to overpressure during the tensioning operation, the overpressure protection valve is added to the jack for pressure relief protection.
At the same time, several commonly used screw and flange plate structures have been improved to strengthen the bearing capacity of the jack to the return oil pressure, greatly reducing the possibility of damaging the jack due to improper operation.
To sum up, the performance of YDC series hydraulic jacks with new structure and new technology has been improved compared with the original core hydraulic jacks, which are widely used in the prestressed construction process of various pretensioning and post-tensioning methods.
Any one prestressed jack for prestressed concrete slabs is not multi-purpose, its tonnage and stroke limited its usage application. The prestressed jack and pump we made, keep its stroke and structure, keep the reasonable height, if so, it can reduce the reserved length of pc strands, and reduce the engineering cost.