System and method for convertible balanced and unbalanced stem valve

A valve assembly, comprising:

• a valve body, the valve body having a bore extending to a valve chamber;
• a valve stem extending through the bore;
• a valve member coupled to the valve stem, the valve member being movable between an open position and a closed position;
• an actuator coupled to the valve stem, the actuator driving axial movement of the valve stem;
• a housing coupled to a valve body opposite the actuator, the housing having a bore extending to the valve chamber;
• a lower stem extending through the bore, the lower stem having lugs proximate a tip, the lugs having a lug diameter that is larger than an adjacent lower stem diameter;
• and
• a valve member nut coupled to the valve member, the valve member nut having an opening to receive at least a portion of the lower stem, the valve member having a reduced diameter portion of the opening, wherein the lugs of the lower stem are arranged axially higher than and aligned with the reduced diameter portion when the valve assembly is configured in an balanced stem operation mode, and the lugs of the lower stem are misaligned with the reduced diameter portion when the valve assembly is configured in an unbalanced stem operation mode.

A method for converting a valve assembly between a balanced stem operation mode and an unbalanced stem operation mode, comprising:

• axially moving a lower stem, coupled to valve member nut of a valve member, in an upward direction, the movement transitioning lugs out of contact with a reduced diameter portion of the valve member nut;
• rotating the lower stem;
• and
• aligning the lugs with a slot formed in the valve member nut.