Balanced globe valve
An essentially fully balanced plug valve is presented in which the flow control contour is interior to the moving member. The sealing edge of the moving member is at the exterior surface relative to the interior contour. This sealing edge is formed by use of matching angles on the interior of the moving member and the exterior of the stationary member. As a result, operation of the plug is fully balanced with the internal fluid pressure of the liquid therein. The sealing surface of the stationary member is positively retained therein to prevent blowout of the sealing surface. Should failure of the sealing surface occur, a secondary metal-to-metal seal will provide fluid containment albeit possibly at a reduced containment level.
1. A balanced plug valve, comprising:
a valve body defining a flow passage between an inlet and an outlet thereof;
a valve seat having a flow regulating internal contoured wall portion;
a balanced plug linearly movable relative to the valve seat such that the internal contoured wall portion is accommodated inside the balanced plug for regulating a flow of fluid through the flow passage, the balanced plug having a first end exposed to fluid pressure from the inlet and a sealing end having a pressure balancing surface configured to be exposed to the fluid pressure from the inlet when in sealing engagement with the valve seat; and
wherein the sealing end of the balanced plug comprises a shoulder land surface.
2. The balanced plug valve of claim 1 , wherein the shoulder land surface is defined between a sealing contact point at an outer most edge of a perimeter wall thereof and a pressure balancing surface defined between the sealing contact point and an inner most edge of the perimeter wall.
3. The balanced plug valve of claim 1 , wherein the shoulder land surface is defined between an inner most edge of the perimeter wall and the pressure balancing surface.
4. A balanced plug valve, comprising:
a valve body defining a flow passage between an inlet and an outlet thereof;
a valve seat having a flow regulating internal contoured wall portion;
a balanced plug linearly movable relative to the valve seat such that the internal contoured wall portion is accommodated inside the balanced plug for regulating a flow of fluid through the flow passage, the balanced plug having a first end exposed to fluid pressure from the inlet and a sealing end having a pressure balancing surface configured to be exposed to the fluid pressure from the inlet when in sealing engagement with the valve seat;
wherein the valve seat comprises groove formed therein, further comprising a seal positioned within the groove; and
wherein the groove terminates in a wrap wall portion, and wherein the wrap wall portion is rolled to retain the seal within the groove.