Abstract: A dual gate valve includes two valve plates that open and close two openings of a valve box, a support bar that supports the two valve plates, a valve rod connected to the support bar, and an operation unit that performs an open and close operation of the two valve plates via the valve rod. The support bar and the valve plate linearly and elongatedly extend in a lateral direction perpendicular to a central axis of the valve rod. The valve rod is connected to a central portion in the long direction of the support bar, and one and the other of the two valve plates are tiltably attached to one end and the other end in the long direction of the support bar via elastic members, respectively.

Abstract: A dual gate valve includes two valve plates that open and close two openings of a valve box, a support bar that supports the two valve plates, a valve rod connected to the support bar, and an operation unit that performs an open and close operation of the two valve plates via the valve rod. The support bar and the valve plate linearly and elongatedly extend in a lateral direction perpendicular to a central axis of the valve rod. The valve rod is connected to a central portion in the long direction of the support bar, and one and the other of the two valve plates are tiltably attached to one end and the other end in the long direction of the support bar via elastic members, respectively.

Abstract: A pair of air cylinders that cause a valve plate to perform an opening/closing operation each include a head-side air cushion mechanism and a rod-side air cushion mechanism. Each head-side air cushion mechanism includes a head-side communication path and a head-side restricting flow path that connect a head-side pressure chamber and a head-side main flow path in parallel, and a blocking mechanism that blocks the head-side communication path when a piston approaches a retreat stroke end, and each rod-side air cushion mechanism includes a rod-side communication path and a rod-side restricting flow path that connect a rod-side pressure chamber and a rod-side main flow path in parallel, and a blocking mechanism that blocks the rod-side communication path when the piston approaches an advance stroke end.

Abstract: A spacer having a wedge-shaped flat plate portion and an engagement protrusion is interposed between a hole end surface of mounting hole of a valve plate and a rod end surface of mounting portion of a valve rod, which thereby forms a wedge-shaped gap between the spacer and the hole end surface so as to open frontward. A fastening force of a valve-plate fixation screw generates a moment M that deforms the valve plate in a direction of narrowing the gap. At the same time, the engagement protrusion of the spacer is pressed into a wedge-shaped space between the inclined surface portion of the rod end surface and the rear hole-wall surface of the mounting hole, which causes the front hole-wall surface of mounting hole of the valve plate to press the rod front surface of mounting portion of the valve rod.

Abstract: When a part of a hole rear wall of a mounting hole formed in a valve plate and a part of a rod rear wall of a mounting portion of a valve rod have formed thereat inclined portions, respectively, that produce a wedge effect by abutting upon each other and when the valve plate and the valve rod are fixed in a direction of an axis by a valve-plate fixing screw, a wedge effect when the inclined portions and abut upon each other causes a rod front wall of the mounting portion and a hole front wall of the mounting hole to come into close contact with each other and the valve plate and the valve rod to be precisely and firmly fixed to each other so as not to rotate relative to each other.

Abstract: A spacer having a wedge-shaped flat plate portion and an engagement protrusion is interposed between a hole end surface of mounting hole of a valve plate and a rod end surface of mounting portion of a valve rod, which thereby forms a wedge-shaped gap between the spacer and the hole end surface so as to open frontward. A fastening force of a valve-plate fixation screw generates a moment M that deforms the valve plate in a direction of narrowing the gap. At the same time, the engagement protrusion of the spacer is pressed into a wedge-shaped space between the inclined surface portion of the rod end surface and the rear hole-wall surface of the mounting hole, which causes the front hole-wall surface of mounting hole of the valve plate to press the rod front surface of mounting portion of the valve rod.

Abstract: A pair of air cylinders that cause a valve plate to perform an opening/closing operation each include a head-side air cushion mechanism and a rod-side air cushion mechanism. Each head-side air cushion mechanism includes a head-side communication path and a head-side restricting flow path that connect a head-side pressure chamber and a head-side main flow path in parallel, and a blocking mechanism that blocks the head-side communication path when a piston approaches a retreat stroke end, and each rod-side air cushion mechanism includes a rod-side communication path and a rod-side restricting flow path that connect a rod-side pressure chamber and a rod-side main flow path in parallel, and a blocking mechanism that blocks the rod-side communication path when the piston approaches an advance stroke end.

Abstract: A valve fixing mechanism for fixing protruding walls of valve housings of adjacent gate valves to a chamber in a fixing space defined between the valve housings includes a support member fixed to the chamber in middle part of the fixing space and a pair of lever members arranged on both sides of the support member. The pair of lever members each include fulcrum part, load part, and effort part arranged in that order from the middle part of the fixing space to an opening at either end of the fixing space. The fulcrum part is supported by the support member, and a force is applied to the effort part by a fixing operation bolt, so that both the load part and the effort part press the protruding walls of the valve housings against the chamber.

Abstract: When a part of a hole rear wall of a mounting hole formed in a valve plate and a part of a rod rear wall of a mounting portion of a valve rod have formed thereat inclined portions, respectively, that produce a wedge effect by abutting upon each other and when the valve plate and the valve rod are fixed in a direction of an axis by a valve-plate fixing screw, a wedge effect when the inclined portions and abut upon each other causes a rod front wall of the mounting portion and a hole front wall of the mounting hole to come into close contact with each other and the valve plate and the valve rod to be precisely and firmly fixed to each other so as not to rotate relative to each other.

Abstract: To provide a gate valve such that two connected surfaces perpendicular to each other of a valve plate housing frame can be connected to two side walls perpendicular to each other of a chamber in such a manner that the connected surfaces are in contact with the side surfaces. When screwing a fixation screw perpendicularly into a screw hole formed in one chamber wall of a chamber through a screw insertion hole formed in one frame wall of a valve plate housing frame of a gate valve, and tightening the fixation screw to press and fix the frame wall against and to the first chamber wall, a thrust force in a direction perpendicular to the axis of the fixation screw is generated in the valve plate housing frame by a cam mechanism formed on the fixation screw and in the screw insertion hole, and the other frame wall of the valve plate housing frame is pressed against and fixed to the other chamber wall of the chamber by the thrust force.

Abstract: A valve fixing mechanism for fixing protruding walls of valve housings of adjacent gate valves to a chamber in a fixing space defined between the valve housings includes a support member fixed to the chamber in middle part of the fixing space and a pair of lever members arranged on both sides of the support member. The pair of lever members each include fulcrum part, load part, and effort part arranged in that order from the middle part of the fixing space to an opening at either end of the fixing space. The fulcrum part is supported by the support member, and a force is applied to the effort part by a fixing operation bolt, so that both the load part and the effort part press the protruding walls of the valve housings against the chamber.

Abstract: In a valve box that makes up a gate valve, a balance room is disposed on one side wall that faces toward a processing chamber. In the balance room, a first seal member is provided to surround a first pathway, and a second seal member is mounted on an outer edge of the balance room. Further, a balance port is formed in the balance room. The balance port communicates with an accommodating room that is formed in the interior of the valve box. In a valve closed state in which a valve disk is seated on a valve seat of the valve box, the pressure inside the accommodating room and the pressure inside the balance room are equalized or made uniform through the balance port.

Abstract: A gate valve that can suppress the deterioration of a seal member due to radicals is provided, and the seal member in the gate valve can be prevented from coming off a dovetail groove. A seal groove for attaching a seal member is formed by a first groove portion that has a rectangular cross-section and a second groove portion that is provided in the bottom wall of the first groove portion and that has a dovetail groove-like cross-section. The seal member is held in the second groove portion with part thereof protruded into the first groove portion. A valve seat that is inserted into and pulled out of the seal groove to be brought into and out of contact with the seal member is protruded from the inner surface of a partition wall in which a gate opening is provided.

Abstract: To provide a gate valve such that two connected surfaces perpendicular to each other of a valve plate housing frame can be connected to two side walls perpendicular to each other of a chamber in such a manner that the connected surfaces are in contact with the side surfaces. When screwing a fixation screw perpendicularly into a screw hole formed in one chamber wall of a chamber through a screw insertion hole formed in one frame wall of a valve plate housing frame of a gate valve, and tightening the fixation screw to press and fix the frame wall against and to the first chamber wall, a thrust force in a direction perpendicular to the axis of the fixation screw is generated in the valve plate housing frame by a cam mechanism formed on the fixation screw and in the screw insertion hole, and the other frame wall of the valve plate housing frame is pressed against and fixed to the other chamber wall of the chamber by the thrust force.

Abstract: A parallel movement mechanism including guide grooves and guide rollers and a perpendicular movement mechanism including cam grooves and cam rollers are interposed between a drive rod of an air cylinder and a valve assembly. By moving the valve assembly parallel to valve seat surfaces formed around a pair of openings of a valve casing with the parallel movement mechanism, and then moving it perpendicularly to the valve seat surfaces with the perpendicular movement mechanism, valve seal members of valve elements can be brought into and out of contact with the valve seat surfaces, and the openings can be selectively opened and closed.

Abstract: To provide a gate valve in which the deterioration of a seal member due to radicals can be suppressed, and the seal member can be prevented from coming off a dovetail groove. A seal groove for attaching a seal member is formed by a first groove portion that has a rectangular cross-section and a second groove portion that is provided in the bottom wall of the first groove portion and that has a dovetail groove-like cross-section. The seal member is held in the second groove portion with part thereof protruded into the first groove portion. A valve seat that is inserted into and pulled out of the seal groove to be brought into and out of contact with the seal member is protruded from the inner surface of a partition wall in which a gate opening is provided.

Abstract: In a valve box that makes up a gate valve, a balance room is disposed on one side wall that faces toward a processing chamber. In the balance room, a first seal member is provided to surround a first pathway, and a second seal member is mounted on an outer edge of the balance room. Further, a balance port is formed in the balance room. The balance port communicates with an accommodating room that is formed in the interior of the valve box. In a valve closed state in which a valve disk is seated on a valve seat of the valve box, the pressure inside the accommodating room and the pressure inside the balance room are equalized or made uniform through the balance port.

Abstract: A parallel movement mechanism including guide grooves and guide rollers and a perpendicular movement mechanism including cam grooves and cam rollers are interposed between a drive rod of an air cylinder and a valve assembly. By moving the valve assembly parallel to valve seat surfaces formed around a pair of openings of a valve casing with the parallel movement mechanism, and then moving it perpendicularly to the valve seat surfaces with the perpendicular movement mechanism, valve seal members of valve elements can be brought into and out of contact with the valve seat surfaces, and the openings can be selectively opened and closed.

Abstract: A parallel movement mechanism including guide grooves and guide rollers and a vertical movement mechanism including cam grooves and cam rollers are interposed between a drive rod and a valve shaft of an air cylinder, and a valve seal of a valve plate is moved vertically toward and away from a valve seat surface to open and close the opening by moving the valve shaft in parallel to the valve seat surface by the parallel movement mechanism and moving the same vertically with respect to the valve seat surface by the vertical movement mechanism.

Abstract: In a gate valve including a valve plate connected to a valve plate mounting portion of at a tip end of a valve rod with a connecting plate and configured to open and close a communicating hole of a valve box with the valve plate, the valve plate includes a mounting hole, a joint flat surfaces coming into press-contact with each other, the valve rod includes a depressed-shaped joint shoulder portion, the joint shoulder portion is formed with an inclined surface configured to guide the valve plate in the direction in which the joint flat surfaces are brought into press-contact with each other, and the coupling plate couples the valve plate and the valve rod with each other.