Valve having pressure balancing piston and method involving same

A valve assembly comprising:

• a housing having a valve chamber, a flow passageway extending through the valve chamber, and a piston chamber;
• a valve member in the housing and movable along a valve axis, the valve member including a plug portion arranged along the flow passageway for regulating fluid flow therethrough, the plug portion subjected to a first pressure urging the valve in a first direction;
• a piston slidable in the piston chamber integral with the valve member, the piston having a first side subjected to the first pressure urging the valve in a second direction opposite said first direction and a second side subjected to a second pressure urging the valve in the first direction;
• a pressure passage providing fluid pressure communication between the first side of the piston and the valve plug portion;
• and
• wherein the valve member is a fuel metering valve that meters fuel flowing along the flow passageway to a turbine engine.

A valve assembly comprising:

• a housing having a valve chamber, a flow passageway extending through the valve chamber, and a piston chamber;
• a valve member in the housing and movable along a valve axis, the valve member including a plug portion arranged along the flow passageway for regulating fluid flow therethrough, the plug portion subjected to a first pressure urging the valve in a first direction;
• a piston slidable in the piston chamber integral with the valve member, the piston having a first side subjected to the first pressure urging the valve in a second direction opposite said first direction and a second side subjected to a second pressure urging the valve in the first direction;
• a pressure passage providing fluid pressure communication between the first side of the piston and the valve plug portion;
• and
• wherein the valve member includes a valve stem, the valve stem including a radially extending working surface area subject to atmospheric pressure, and wherein the second pressure is atmospheric fluid pressure, and wherein the second side of the piston has a radially extending working surface area that is sized relative to the working surface area of the valve stem to reduce actuation force needed for moving the valve member.

A valve assembly comprising:

• a housing having a valve chamber, a flow passageway extending through the valve chamber, and a piston chamber;
• a valve member in the housing and movable along a valve axis, the valve member including a plug portion arranged along the flow passageway for regulating fluid flow therethrough, the plug portion subjected to a first pressure urging the valve in a first direction;
• a piston slidable in the piston chamber integral with the valve member, the piston having a first side subjected to the first pressure urging the valve in a second direction opposite said first direction and a second side subjected to a second pressure urging the valve in the first direction;
• a pressure passage providing fluid pressure communication between the first side of the piston and the valve plug portion;
• and
• wherein the valve housing comprises a valve body, a valve cage mounted in the valve body, and a valve bonnet mounted to the valve body, the valve member slidably engaging the valve cage, and wherein the pressure passage extends through the valve member into an intermediate chamber defined between the valve member and the valve cage and through an axially extending passage formed in the valve cage to the piston chamber, the piston chamber being defined in the valve cage, wherein fluid pressure in the intermediate portion axially urges the valve member in said second direction.

A valve assembly, comprising:

• a valve housing having a valve chamber, a flow passageway extending through the valve chamber, a piston chamber, and an annular valve seat surrounding the flow passageway;
• a generally cylindrical valve member axially movable in the valve chamber toward and away the valve seat to close and open the flow passageway, the valve member including at least three different diameters to include a plug portion and a stepped stem portion, the plug portion including an end face engaging the valve seat when closed and subjected to a first pressure urging the valve in a first direction, wherein a radially extending first working face is defined between the plug portion and the stem portion, the first working face being subjected to the first pressure contained in an intermediate chamber between the stem portion and the valve housing, the intermediate chamber interposed axially between the piston chamber and the flow passageway;
• a piston slidable in the piston chamber integral with the valve member, the piston having a first side subjected to the first pressure urging the valve in a second direction opposite said first direction and a second side subjected to a second pressure urging the valve in the first direction;
• and
• a pressure passage having a continuous open state providing fluid communication between the piston chamber along first side of the piston, the intermediate chamber and the end face of plug portion for all operating positions of the valve member.