Event: Coiler Mandrel - Expand (Retract)

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

 

1)    Accumulators 236.16 and 237.17 are used to maintain pressure during the expansion of the mandrel and to maintain pressure in the event of a loss of supply pressure in the P1 pressure header line. Check Valve 157.57 prevents fluid stored in the accumulators from flowing back into the pressure header line.

2)    Proportional Directional Control Valve 346.03 is energized to the parallel flow pattern allowing pressurized hydraulic fluid to flow through the valve, passing from P to A. This fluid then flows into the rod end of Coiler Mandrel 811 causing the mandrel to retract and expand.

3)    Exhaust fluid from the cap end of the mandrel flows through the proportional directional control valve, passing from B to T, and then back to tank after flowing through Duplex Return Line Filter 045.03.

4)    Note that the retraction speed of the mandrel is controlled by the proportional directional control valve.