Abstract: A valve for controlling flow of a fluid exerting a fluid pressure. The valve has a body including a fluid passage for the fluid, and a valve seat positioned adjacent to the fluid passage at an orifice coaxial with the fluid passage. The valve seat includes a sealing gland defining a cavity therein, and the sealing gland has a support surface adjacent to the cavity and a resilient valve seat member within the cavity. The valve seat member includes a first pressure responsive surface adjacent to the orifice and a second pressure responsive surface substantially opposed to the first pressure responsive surface. The support surface includes a notch for positioning a portion of the support surface a distance apart from the second pressure responsive surface.

Abstract: The present invention provides a valve comprising a body including a fluid passage, a valve seat, defining an orifice, and including a sealing gland including a support surface, the support surface including a notch, and a resilient valve seat member disposed within the sealing gland, and a valve sealing member disposed within the fluid passage and configured to seat against the valve seat member to effect sealing of the valve sealing member to the valve seat and thereby close the orifice, wherein the notch is configured to facilitate application of a fluid pressure on the valve seat member to prevent leakage through the orifice when the valve sealing member is seated against the valve seat member. In one embodiment, the notch is provided in the valve seat member and not the sealing gland support surface.