Balanced stem and surface safety valve

A system for controlling a flow of fluid through a flow passage, comprising:

• a valve body having a bore extending along an axis transverse to the flow passage;
• a stem extending through the bore;
• a valve member coupled to a lower end of the stem, the valve member being moveable between an open position and a closed position;
• and
• a balancing system coupled to the valve member including a flexible tether and a balance member, wherein the flexible tether is coupled to the valve member at a first end and to the balance member at a second end and moves between a slack configuration and a taut configuration, the balance member being moveable axially along the axis in response to movement of the valve member.

A system for controlling a flow of fluid through a flow passage, comprising:

• a valve body having a bore extending along an axis transverse to the flow passage;
• a stem extending through the bore;
• a valve member coupled to the stem, the valve member being moveable between an open position where the flow passage is unobstructed and a closed position where the flow passage is obstructed;
• and
• a balancing system coupled to the valve member and confined within a common chamber with the valve member, the balancing system including a tether and a balance member, wherein the tether is coupled to the valve member at a first end and to the balance member at a second end, the tether axially moveable within a cavity formed in the valve member.