Description of hydraulic strand jack system:
The strand jack lifting technique originates from the concrete post tensioning principle. A strand jack can be considered a linear winch. In a strand jack, a bundle of steel cables or strands are guided through a hydraulic cylinder; above and below the cylinder are anchor systems with wedges that grip the strand bundle. By stroking the cylinder in and out while the grips are engaged in the anchors, a lifting or lowering movement is achieved.
The motion of the cylinders is driven by hydraulic power packs. They can be electric or diesel powered. Our sophisticated SCC software program synchronizes the motion of the strand jacks and adjusts the motion to the loads per lifting point.
hydraulic strand jack system is a new type of large-scale lifting equipment, mainly by the ZTS series to enhance the jack, hydraulic pump station, control system components.
Strand Jack operation:
Step 1.The bottom collets are closed and hold the load while the main ram is retracted. The hydraulic oil is supplied to retract the ram while the tope collects are open and do not grip the strand. The load is stationary during this part of the cycle.
Step 2. The top collects are engaged and the hydraulic oil is supplied to the other side of the piston causing the load to advance. While the load is being raised the bottom collets are open and do not grip the strand.
Step 3. Repeat step 1.
Step 4. Repeat step 2.
When raising or lowering a load, a built-in displacement transducer measures the movement of each strand jack. The central control system keeps track of all strand jack displacements and corrects for an errors that may accumulate. While the operation demonstrated in realates to raising a load, the lowering operations is very similar except that the phasing of the collet operation is reversed.