Abstract: Apparatus for increasing stiffness in a seal are disclosed. A disclosed apparatus includes a first flexible member having a curved sealing surface and a second flexible member adjacent to a retainer side of the first flexible member. The second flexible member is configured to increase a stiffness of the first flexible member in one of a plurality of flow directions.

Abstract: A fluid control valve for controlling fluid flow includes a valve housing having an inlet port, an outlet port, and a passage in the valve housing interconnecting and permitting fluid communication between the inlet port and the outlet port. The passage is substantially smoothly contoured along the length of the interior thereof so that when fluid flows through the passage, the flow of fluid will not substantially increase in turbulence in the passage. The fluid control valve further includes a removable valve seat having an inner flow aperture substantially matching the interior contour of the passage thereby minimizing the turbulence of fluid flow in the passage. A valve element is moveable between a first position wherein fluid flow is permitted through the passage and a second position wherein the valve element sealingly engages the valve seat substantially blocking fluid flow through the passage. The valve seat is removably mounted in the passage.