Patent ID: 7051746

Claim:
A method of balancing fluid forces across a plug valve comprising the steps of: regulating a flow of fluid along a flow passageway with a valve member, the valve member including a plug portion that is adapted to restrict flow and a valve stem, the fluid acting upon the plug portion and being at a first pressure to provide a first force urging the valve member in a first direction; actuating the valve stem to drive the valve member; counteracting at least part of the first force with a second force generated by a piston integral with the valve member and slidable in a piston chamber, the piston having a first side subjected to the first pressure and a second side vented to ambient; communicating the first pressure from the flow passageway to the piston chamber on the first side; and porting the first pressure to a radially extending working surface of the valve member, the first pressure acting upon the radially extending working surface separate from the piston to urge the valve member in a second direction opposite said first direction to further counteract said first force.