Patent TW-201938935-A (TW)
Title: Slide valve
Inventor: WADA SHINICHI
IPC: F16K51/02
Filed: 2019-03-15
Abstract: A slide valve of the invention includes: a valve box having a hollow, a first opening, and a second opening, the first opening and the second opening being provided so as to face each other with the hollow interposed therebetween and forming a flow passage passing through the hollow; a neutral valve body that is arranged in the hollow of the valve box and is capable of sealing the first opening; a rotation shaft that rotate the neutral valve body between a valve sealing position at which the neutral valve body is in a state of sealing the first opening and a valve opening position at which the neutral valve body is in a state of being retracted from the first opening; a rotation driver that is constituted of a rack pinion rotating the rotation shaft and a rotation air cylinder driving the rack pinion; a sealing release driver that is constituted of a sealing release air cylinder that carries out operation of releasing seal of the neutral valve body; and a sequence circuit that is capable of sequentially allowing operation of releasing seal of the neutral valve body and operation of rotating the neutral valve body. The rotation air cylinder includes: a piston that is capable of being operated integrally with the rotation air cylinder; a first pressure space and a third pressure space that are capable of carrying out closing operation of the piston; and a second pressure space and a fourth pressure space that are capable of carrying opening operation, wherein the first pressure space, the second pressure space, the third pressure space, and the fourth pressure space are disposed in series in an operation direction of the piston. The sequence circuit includes: an air operated three-channel spool valve; an air operated two-channel spool valve; a speed control valve in which a check valve and a flow control valve are combined; a check valve; and a rotational-operation completion detecting switch valve that is provided in parallel with the check valve and is capable of maintaining the sealing pressure in a state where a sealing pressure of the sealing release air cylinder is stabilized until operation of rotating the neutral valve body is completed. When the slide valve is opened due to supply of drive compressed air in one line and when drive of the sealing release air cylinder is completed, the sequence circuit causes the first pressure space to be in a non-pressurized state, causes the second pressure space to be in a pressurized state, causes the third pressure space and the fourth pressure space to be in a pressurized state, and thereby starts opening operation of the rotation air cylinder. When the slide valve is closed due to releasing the supply of drive compressed air, the sequence circuit causes the first pressure space and the second pressure space to be in a non-pressurized state, causes the third pressure space to be in a hermetically-sealing maintaining state in a pressurized state, causes the fourth pressure space to be in a non-pressurized state, and thereby starts closing operation of the rotation air cylinder and starts sealing operation by the sealing release air cylinder when the rotation operation is completed.