VALVE

摘要

A valve where durability of a sealing member formed from an elastic body is improved and which is capable of optimally maintaining sealing ability in a wide range from a high pressure difference to a low pressure difference. A valve (100) has a valve body (1) and a valve seat (2) that are in tight contact with each other with a sealing member (5) provided on the valve body (1) or on the valve seat (2) in between. The valve (100) has a restricted section (30) narrowing a flow path, and is defined by the shape of the valve body (1) and/or the valve seat (2) and constructed between the valve body and the valve seat. The restricted section (30) is provided in the periphery of the sealing member (5). In a closing operation of the valve body (1), the flow path narrowed by the restricted section (30) is narrowed before a flow path directly near the sealing member (5) is narrowed.