Patent ID: 8186377

Claim:
A fluid switching valve device comprising: a valve seat portion including a protrusion portion; a valve body contacting and separating from the valve seat portion to communicate and block between upstream and downstream paths in a fluid passage during normal operation of the valve device, wherein: the valve body includes a first seal portion sealing between the valve seat portion and the valve body and a second seal portion having higher hardness than the first seal portion; a direction in which the valve body contacts and separates from the valve seat portion and a flow direction of the fluid introduced from the upstream path in the fluid passage cross each other during the normal operation of the valve device; the first seal portion and the second seal portion are arranged parallel to each Other and disposed in a direction orthogonal to the valve body contact/separation direction; and in blocking the fluid passage by a differential pressure between upstream and downstream paths in the fluid passage, when the differential pressure is less than a predetermined value, the first seal portion is allowed to come into close contact with the protrusion portion of the valve seat portion for blocking of the fluid passage and, on the other hand, when the differential pressure is the predetermined value or higher, the first seal portion in close contact with the protrusion portion of the valve seat portion is allowed to be compressively deformed by the differential pressure and the second seal portion is allowed to come into close contact with the valve seat portion for blocking of the fluid passage, wherein the fluid flows in the flow direction and is prohibited from flowing in any other direction, wherein the first seal portion is disposed only inwardly from the second seal portion, and wherein both the first and second seal portions contact the valve seat portion at flat, non-tapered surfaces.