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 Pinch Roll Exit Side Cylinder - Lowering (Extend)

Event: Pinch Roll Exit Side Cylinder - Lowering (Extend)

For previous sequences in this event see the event “Roll Change HPU – On.”

 

1)    Incoming pressure is reduced to 70 bar by Pressure Reducing Valve 277.03.

2)    Directional Control Valve 302.38 is energized to the parallel flow pattern allowing pressurized hydraulic fluid to flow through the valve passing from P to A, then into the cap ends of Exit Side Pinch Roll Cylinders 653.01 and 653.02 causing the cylinders to extend.

3)    Exhaust fluid from the cap end of Exit Side Pinch Roll Cylinder 653.01 flows unrestricted through the check valve in Flow Control Valve 182.01. However, when the exhaust fluid flows through Flow Control Valve 182.02, the check valve in that flow control valve forces the exhaust fluid to flow though the needle valve of 182.02, thereby achieving meter-out flow control of the extension speed of the cylinder.

4)    Similarly, exhaust fluid from the cap end Exit Side Pinch Roll Cylinder 653.02 flows unrestricted through the check valve in Flow Control Valve 182.03. However, when the exhaust fluid flows through Flow Control Valve 182.04, the check valve in that flow control valve forces the exhaust fluid to flow though the needle valve of 182.04, thereby achieving meter-out flow control of the extension speed of the cylinder.

5)    Then the exhaust fluid from both cylinders combines and flows through the B-port check valve of Dual Pilot Operated Check Valve Module 172.26, which has been piloted open by pilot pressure from the A-side of the circuit.

6)    Finally, the exhaust fluid flows through the directional control valve, passing from B to T, then back to tank after flowing through Check Valve 122.07 and Duplex Return Line Filter 045.01.

7)    Note that Pressure Relief Valve 268.18 protects the cap end of the cylinders from overpressure caused by external load forces. In the event the cylinders are forced to retract, Check Valve 159.37 will provide makeup fluid to the rod ends of the cylinders to prevent cavitation of the rod ends.