Mechanism and method to adjust size of balanced valve

A regulator valve comprising,

• a valve body defining a fluid flow passage having a valve throat disposed between an inlet and an outlet;
• an actuator operatively coupled to the valve body;
• and
• a balanced valve trim comprising:
• a seat ring coupled to the valve body, the seat ring defining a flow through orifice having a first cross-sectional area;
• and
• a flow control member, the flow control member including a sleeve operatively connected to the actuator so as to move a valve disk assembly toward and away from the seat ring so as to control flow of fluid through the fluid flow passage, the sleeve having an interior space disposed between a first end of the sleeve and a second end of the sleeve, the valve disk assembly disposed at the second end of the sleeve, an inner annular shoulder disposed toward the first end of the sleeve and spaced apart from the valve disk assembly to at least partially define the interior space, and a through bore extending through the inner annular shoulder, wherein the valve disk assembly includes a passageway to provide fluid communication between the fluid flow passage and the interior space;
• and
• a plunger slidingly disposed within the through bore and fixed relative to the valve body,
• wherein the plunger forms a seal with an inner surface of the through bore.

A balanced valve trim for a regulator valve, comprising:

• a seat defining a flow through orifice for fluid flowing through a valve body;
• and
• a flow control member for controlling flow of the fluid through the flow through orifice, the flow control member including:
• a sleeve to be operatively connected to an actuator so as to move toward and away from the seat, the sleeve having a first end, a second end opposite the first end, an interior space extending along the sleeve between the first end and the second end, an inner annular shoulder disposed between the first end and the second end to at least partially define the interior space, and a through bore extending through the inner annular shoulder;
• a valve disk assembly disposed at the second end and arranged to engage the seat, wherein the valve disk assembly includes a passageway to provide fluid communication with the interior space;
• and
• a plunger having a first end disposed in the through bore and a second end disposed outside of the through bore,
• wherein a first effective pressure area is defined at the first end of the interior space, and a second effective pressure area is defined at the second end of the interior space, and the second effective pressure area opposes the first effective pressure area.