A valve, having a valve housing which has a fluid inlet chamber and a fluid outlet chamber, having a valve seat which is arranged between the fluid inlet chamber and the fluid outlet chamber, and having a closure body which is movable back and forth between a release position and a blocking position. The closure body abuts against the valve seat in a fluid-tight manner in the blocking position, and wherein the fluid inlet chamber and the fluid outlet chamber are connected to one another in a fluid-conducting manner in the release position. The valve seat and the closure body each have a sealing surface, which are opposite one another in the blocking state, and an elastically deformable sealing element which is arranged between the sealing surfaces in the blocking state and which completely stretches over one of the sealing surfaces.

An air shut-off valve apparatus for a fuel cell system is provided. The apparatus includes a valve body having an inlet-side air passage through which supply air flows and an outlet-side air passage through which exhaust air flows. A valve flap is installed in the valve body to open or close the inlet-side air passage and the outlet-side air passage. An inlet-side check valve is opened when pressure of the supply air is greater than or equal to a predetermined pressure, to guide the supply air into the fuel cell stack through the inlet-side air passage even while the valve flap is closed. An outlet-side check valve is opened when pressure of the exhaust air is greater than or equal to a predetermined pressure, to guide the exhaust air released from the fuel cell stack to flow through the outlet-side air passage even while the valve flap is closed.

An air shut-off valve apparatus for a fuel cell system is provided. The apparatus includes a valve body having an inlet-side air passage through which supply air flows and an outlet-side air passage through which exhaust air flows. A valve flap is installed in the valve body to open or close the inlet-side air passage and the outlet-side air passage. An inlet-side check valve is opened when pressure of the supply air is greater than or equal to a predetermined pressure, to guide the supply air into the fuel cell stack through the inlet-side air passage even while the valve flap is closed. An outlet-side check valve is opened when pressure of the exhaust air is greater than or equal to a predetermined pressure, to guide the exhaust air released from the fuel cell stack to flow through the outlet-side air passage even while the valve flap is closed.

The invention relates to a valve (100) having a valve housing (3) which has a fluid inlet chamber (21) and a fluid outlet chamber (23), having a valve seat (12) which is arranged between the fluid inlet chamber (21) and the fluid outlet chamber (23), and having a closure body (50) which is movable back and forth between a release position and a blocking position, wherein the closure body (50) abuts against the valve seat (12) in a fluid-tight manner in the blocking position, and wherein the fluid inlet chamber (21) and the fluid outlet chamber (23) are connected to one another in a fluid-conducting manner in the release position.

According to the invention, it is proposed that the valve seat (12) and the closure body (50) each have a sealing surface (13a,b), which are opposite one another in the blocking state, and an elastically deformable sealing element (4) which is arranged between the sealing surfaces (13a,b) in the blocking state and which completely stretches over one of the sealing surfaces.

The present disclosure provides a valve device including a housing, a shaft, a butterfly valve, and a sealing member. The butterfly valve has a disk shape and defines a groove formed on an outer circumferential surface. The butterfly valve is fixed to the shaft and housed in a passage in the housing to selectively open and close the passage. The sealing member has an annular shape and fit into the groove. The outer circumferential surface of the sealing member has an arc surface having a diameter equal to the diameter of the passage. The arc surface comes into contact with the inner wall of the passage when the passage is closed.

The present disclosure provides a valve device including a housing, a shaft, a butterfly valve, and a sealing member. The butterfly valve has a disk shape and defines a groove formed on an outer circumferential surface. The butterfly valve is fixed to the shaft and housed in a passage in the housing to selectively open and close the passage. The sealing member has an annular shape and fit into the groove. The outer circumferential surface of the sealing member has an arc surface having a diameter equal to the diameter of the passage. The arc surface comes into contact with the inner wall of the passage when the passage is closed.