Event: Top Roll Balancing Cylinders - Retract

For previous steps in this sequence see the event “HPU – On.”

 

Note that the rod ends of Top Roll Balancing Cylinders 815.01 and 815.02 are pinned to the Upper Pinch Roll.

 

The cap ends of the balancing cylinders are constantly pressurized to 20 bar by pressurized hydraulic fluid controlled by Pressure Reducing-Relieving Valve 277.04. Check Valve 159.43 prevents pressurized fluid from flowing back towards the secondary (outlet) port of the pressure reducing valve. Pressure Relief Valve 271.02 protects the cap ends of the cylinders from overpressure. Accumulator 242.25 compensates for pressure and volume changes in the event of a sudden change in the cylinder stroke positions. The cylinder rod sides operate at a pressure of 210 bar.

 

1)    Pressurized hydraulic fluid flows through Check Valve 159.42 to the P-port of Directional Control Valve 304.08 which is energized to the parallel flow pattern allowing the fluid to pass through the valve from P to A. The fluid then flows freely through the A-port check valve in Flow Control Valve Module 179.32 and into the rod ends of the balancing cylinders, causing the cylinders to retract.

2)    Exhaust flow from the cap ends of the cylinders may be absorbed by Accumulator 242.25 or, if the volume is great enough, the overpressure fluid will be relieved to tank through Pressure relief Valve 271.02.