The application describes a valve device which can be used to open and shut a laterally arranged inlet in an inclined wall of a mixer granulator and which can be used in an automatic operation. The valve device comprises a main body (1) and a piston (2), the piston being movable between a retracted position and an advanced position. The piston (2) comprises a face (3) at its forward end which is inclined to the direction of movement and the device comprises means (24,19) to rotate the piston as it advances and retracts. Thus, the face of the piston can open and close an opening in a wall which extends in a direction at an angle to the said direction of movement of the piston.
A stop valve for a gas tank is provided which achieves favorable sealing performance by inhibiting rotation of a sealing member attached to a valve element. A passage is formed inside a valve body, and a valve seat is provided in the passage. The valve element which is engaged and disengaged from the valve seat is slidably inserted to a sliding hole bored in the valve body. The annular sealing member is arranged in sliding contact with the outer peripheral surface of the valve element and the inner peripheral surface of the sliding hole. A screw hole connecting to the sliding hole and coaxial thereto is provided in the valve body. A rotating operation member having a male screw is rotatably screwed into the screw hole from the outside of the valve body. One end of the rotating operation member is made to abut the valve body.
