| 摘要 |
A piston valve capable of smoothly operating a piston without being affected by a hydraulic pressure by the balance of an operating force pressurizing a valve disc in a forward direction with an operating force pressurizing it in a backward direction, wherein the valve disc (2) is moved reciprocatingly between a first valve port (4a) and a second valve port (4b) according to the reciprocating movement of the piston (1) so as to communicate a main flow passage (40) with a second flow passage (42) when the first valve port is closed and to communicate the main flow passage with a first flow passage (41) when the second valve port (4b) is closed, the base end of a valve rod (22) is connected to the valve disc by extending the valve rod in the direction opposite to a valve stem (20), and the cross-sectional area of the valve stem is made equal approximately to that of the valve rod so that the operating force pressurizing the valve disc in a forward direction becomes equal approximately to that pressurizing it in a backward direction. |
