Gate valve

Abstract

[Problem] The present invention provides a gate valve that can suppress the increase in weight and cost. [Solution] The gate valve (10) is disposed between the first and second chambers, such that the first opening through the first chamber and the second opening through the second chamber are connected to each other and are opened and closed separately. The gate valve includes: a valve shaft (17); first and second valve plates (21, 22) mounted at the front end; an operating mechanism (24) that moves the valve plates to a retracted position where they communicate with each other at the first and second openings, a first closed position where the first valve plate closes the first opening, and a second closed position where the second valve plate closes the second opening; a fastening mechanism (30) that secures the valve plates to the valve shaft in a manner in which the front end of the valve shaft is held between the valve plates, and that allows the valve plates to be detachably mounted at the front end of the valve shaft; and a support mechanism (50) that secures the valve plates to each other in a detachable manner at at least two ends in the longitudinal direction.

Description

Technical Field

[0001] This invention relates to a gate valve disposed between chambers in a semiconductor manufacturing apparatus or the like. More specifically, it is a gate valve disposed between a first chamber such as a material chamber and a second chamber such as a processing chamber that are adjacent to each other, such that a first opening communicating with the first chamber and a second opening communicating with the second chamber are connected to each other or are opened and closed separately. Prior Technology

[0002] In the gate valve described above, a pair of valve plates are arranged facing away from each other, with the sealing members mounted on these valve plates abutting against the plate surface formed around each of the openings, thereby allowing the openings to be opened and closed individually. However, for example, the sealing members may deteriorate with use, thus necessitating replacement with new sealing members at the deterioration stage, and therefore requiring regular maintenance of the valve plates. However, in the past, when performing maintenance work on the valve plates, such as prioritizing the replacement of the sealing members, it was necessary to remove the entire gate valve from the chamber, which required a significant amount of labor and time.

[0003] Therefore, in the gate valve described in Patent Document 1, a support plate is detachably mounted from the front end of the valve shaft at the front end of the valve shaft, and a pair of valve plates are detachably mounted from the front end of the valve shaft on both sides of the support plate. Thus, for example, as described in Patent Document 1, by removing the top plate from the front end of the valve box that encloses the valve plates, maintenance of the valve plates can be easily performed without removing the entire gate valve from between the chambers when approaching the valve plates or support plate from the front end. On the other hand, considering manufacturing and operational costs, it is preferable to minimize the weight around the valve plates as much as possible. [Previous Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2011-94795 Summary of the Invention

[0005] [The problem that the invention aims to solve]

[0006] Therefore, the technical objective of this invention is not only to provide a valve plate maintenance procedure, but also to suppress the weight around the valve plate to reduce the cost of gate valves. [Methods used to solve problems]

[0007] To address the above issues, the gate valve 10 of the present invention is disposed between adjacent first and second chambers, allowing communication between a first opening of the first chamber and a second opening of the second chamber, or allowing them to open and close separately. The gate valve is characterized by having: a valve shaft extending axially from a base end to a front end; first and second valve plates, each having: an inner surface mounted on the axial front end of the valve shaft, elongated in a direction orthogonal to the shaft and facing the valve shaft, and an outer surface with an annular sealing member facing away from the inner surface; and an operating mechanism that, by actuating the valve shaft, causes the first and second valve plates to open towards the first and second openings. The gate valve has the following features: a retractable position that is connected to each other; a first closed position that closes the first opening with the outside of the first valve plate; and a second closed position that closes the second opening with the outside of the second valve plate. Furthermore, the gate valve includes: a fastening mechanism that abuts the inner surfaces of the first and second valve plates against the front end of the valve shaft, holding the front end of the valve shaft between the valve plates, thereby detachably fastening the first and second valve plates to the valve shaft, so that the first and second valve plates are detachably mounted on the front end of the valve shaft; and at least one set of support mechanisms that detachably fasten the valve plates to each other at at least two ends along the longitudinal direction of the first and second valve plates.

[0008] At this point, the aforementioned fastening mechanism is preferably provided, comprising: a first clamping piece, disposed at the front end of the valve shaft along the axial direction, spanning between the valve shaft and the first valve plate, detachably engaging with the first valve plate and detachably fixed with respect to the valve shaft; a second clamping piece, disposed at the front end of the valve shaft along the axial direction, spanning between the valve shaft and the second valve plate, detachably engaging with the second valve plate and detachably fixed with respect to the valve shaft; and a first fastening member and a second fastening member, which detachably fix the first clamping piece and the second clamping piece to the front end of the valve shaft, respectively. The axial base end of the valve plate is engaged with the front end of the valve shaft from the front end side. With the first and second clamping pieces fixed to the valve shaft by the first and second fastening members, the front ends of the first and second valve plates are pushed toward the inner surfaces of the valve shaft by the engagement of the first and second clamping pieces with the first and second valve plates. In addition, the base end of the valve plate is engaged with the front end of the valve shaft by the engagement of the axial base end of the valve plate with the front end of the valve shaft, thereby pushing the base end of the first and second valve plates toward the inner surfaces of the valve shaft. In this way, the first and second valve plates are fastened to the front end of the valve shaft.

[0009] Furthermore, ideally, the engagement between the base end of the pair of valve plates and the front end of the valve shaft is formed by the engagement of engagement portions respectively provided at the base end of the pair of valve plates and a pair of engaged portions provided at the front end of the valve shaft. The engagement portion is one of a recess and a protrusion that engages with it, and the engaged portion is the other of the recess and the protrusion. The first valve plate and the second valve plate have a first engagement recess and a second engagement recess that open towards the front end of the axial direction at the center of their longitudinal direction on their inner surfaces. The first clamping piece and the second clamping piece have a first engagement protrusion and a second engagement protrusion that engage with the first and second engagement recesses. The engagement is achieved by engaging the first engagement protrusion with the first engagement recess, such that the engagement portions formed on the first valve plate and the valve shaft are engaged with the engaged portions. The first clamping piece is fixed to the valve shaft by the first fastening member, so that the first engaging protrusion exerts a pushing force in the inner direction of the first valve plate relative to the first engaging recess, and the engaging portion exerts a pushing force in the inner direction of the first valve plate relative to the engaged portion, thereby fastening the first valve plate to the valve shaft. The second engaging protrusion engages with the second engaging recess, and in the state where the engaging portion formed on the second valve plate and the valve shaft is engaged with the engaged portion, the second clamping piece is fixed to the valve shaft by the second fastening member, so that the second engaging protrusion exerts a pushing force in the inner direction of the second valve plate relative to the second engaging recess, and the engaging portion exerts a pushing force in the inner direction of the second valve plate relative to the engaged portion, thereby fastening the second valve plate to the valve shaft.

[0010] Ideally, the first and second fastening components are a first fastening bolt and a second fastening bolt, with threaded holes for threading the fastening bolts provided on the axial front end face of the valve shaft. The first and second clamping pieces have through holes for inserting the first and second fastening bolts. The first fastening bolt is inserted through the through hole of the first clamping piece and screwed into the threaded hole of the valve shaft, thereby fixing the first clamping piece to the valve shaft. The second fastening bolt is inserted through the through hole of the second clamping piece and screwed into the threaded hole of the valve shaft, thereby fixing the second clamping piece to the valve shaft.

[0011] Ideally, the first clamping piece has a first engaging protrusion at one end separated from its through hole and a first locking pawl at the other end. When the first clamping piece is fixed with the first fastening bolt, the first locking pawl is locked to the valve shaft with respect to the first engaging protrusion. Similarly, the second clamping piece has a second engaging protrusion at one end separated from its through hole and a second locking pawl at the other end. When the second clamping piece is fixed with the second fastening bolt, the second locking pawl is locked to the valve shaft with respect to the second engaging protrusion.

[0012] Furthermore, ideally, the first clamping piece, in a state of loosening the first fastening bolt, between the engaged position where the first engaging protrusion engages with the first engaging recess, and the disengaged position where the first engaging protrusion is removed from the first engaging recess, can freely rotate around the axis of the first fastening bolt. When the first clamping piece is rotated from the engaged position to the disengaged position, it is housed between the inner surface of the first valve plate and the inner surface of the second valve plate. Within the gap, the second clamping piece, in the state of loosening the second fastening bolt, between the engaged position where the second engaging protrusion engages with the second engaging recess and the disassembled position where the second engaging protrusion is removed from the second engaging recess, freely rotates around the axis of the second fastening bolt. When the second clamping piece is rotated from the engaged position to the disassembled position, it is housed within the gap between the inner surface of the first valve plate and the inner surface of the second valve plate.

[0013] Furthermore, the first and second fastening bolts described above ideally have: an axially extending shaft portion; a head portion provided at the axially forward end of the shaft portion; and an external thread portion formed on the outer periphery of the shaft portion. An internal thread portion that can engage with the external thread portion is formed on the inner surface of the through hole provided in the first and second clamping pieces. The shaft portion further has a fine diameter portion whose outer diameter is smaller than the inner diameter of the internal thread portion in the head side than the external thread portion. The fine diameter portion is inserted into the through hole. When the first and second fastening bolts are loosened, the head side end of the external thread portion abuts against the internal thread portion of the first and second clamping pieces.

[0014] Furthermore, a more ideal support mechanism includes: at least one pair of support platforms, clamped between the first and second valve plates at at least two ends along their longitudinal direction; a third clamping piece, disposed across the first and second valve plates from the respective axial front ends of the pair of support platforms, detachably engaged with the first and second valve plates, and detachably fixed relative to each support platform; and a third fastening member, detachably fixing the third clamping piece to the axial front end of the support platform. The axial base end of the first and second valve plates is engaged with the support platform from the front end. When the third clamping piece is engaged with the first and second valve plates and the base end of the pair of valve plates is engaged with the support platform, the third clamping piece is fixed to the support platform by the third fastening member, thereby pushing the front end and base end of the first and second valve plates toward the inner surfaces respectively, so that the first and second valve plates are fastened to the support platform.

[0015] Furthermore, ideally, the engagement between the base end faces of the pair of valve plates and the support platform is formed by the engagement of base end side engagement recesses provided on the base end faces of the pair of valve plates and base end side engagement protrusions provided on one of the support platforms. The first valve plate and the second valve plate have a third engagement recess and a fourth engagement recess formed on their inner surfaces, with at least two ends opening towards the front end of the axial direction. The third clamping piece has a third engagement protrusion and a fourth engagement protrusion that engage with the third engagement recess and the fourth engagement recess, thus engaging the third engagement protrusion and the fourth engagement protrusion on the upper... The third and fourth engaging recesses are described above. When the base-end side engaging recesses and base-end side engaging protrusions formed on the first and second valve plates and the support platform are engaged, the third fastening member fixes the third clamping piece to the support platform. This causes the third engaging protrusion to exert a pushing force in the inward direction of the first valve plate relative to the third engaging recess and the fourth engaging protrusion to exert a pushing force in the inward direction of the first valve plate relative to the base-end side engaging protrusion, thereby fastening the first and second valve plates and the support platform to each other.

[0016] Alternatively, ideally, the third fastening member is a third fastening bolt. A threaded hole for threading the third fastening bolt is provided on the front end face of the support platform in the axial direction. A through hole for inserting the third fastening bolt is provided on the third clamping piece. The third fastening bolt is inserted through the through hole of the third clamping piece and threaded into the threaded hole of the support platform, thereby fixing the third clamping piece to the support platform.

[0017] Ideally, the third, fourth, and base-end side engaging recesses extend along the longitudinal direction of the valve plate, with their outer ends opening outwards along their longitudinal direction. The support platform engages the third and fourth engaging protrusions of the third clamping piece with the third and fourth engaging recesses of the first and second valve plates, respectively, such that the base-end side engaging recess engages with the base-end side engaging protrusion. By loosening the third fastening bolt, the third and fourth engaging protrusions slide along the third and fourth engaging recesses, and the base-end side engaging recess slides along the base-end side engaging protrusion, allowing the support mechanism to be removed from the first and second valve plates.

[0018] Furthermore, ideally, the third clamping piece loosens the third fastening bolt, thereby engaging the third engaging protrusion with the third engaging recess, and engaging the fourth engaging protrusion with the fourth engaging recess, allowing free rotation around the axis of the third fastening bolt. The third clamping piece further has a protruding portion that projects radially outward from the third fastening bolt. On this protruding portion, the third and fourth engaging recesses engage with a fifth engaging protrusion at their forward end in the protruding direction. The third and fourth engaging protrusions are positioned on either side of the third fastening bolt in the radial direction. The fifth engaging... The protrusion is positioned at a right angle to the axis of the third fastening bolt relative to the third and fourth engaging protrusions. The third clamping piece is engaged with the third and fourth engaging recesses by the third and fourth engaging protrusions. Loosening the third fastening bolt allows the third clamping piece to rotate around the axis of the third fastening bolt, thereby engaging the fifth engaging protrusion with either the third or fourth engaging recess to lock either the first or second valve plate. It can also release the other valve plate from engagement with the third clamping piece by using one of the valve plates.

[0019] Furthermore, the third fastening bolt described above ideally has: an axially extending shaft portion; a head portion disposed at the axially forward end of the shaft portion; and an external thread portion formed on the outer periphery of the shaft portion. An internal thread portion that can engage with the external thread portion is formed on the inner surface of the through hole opened in the third clamping piece. The shaft portion further has a portion that is further on the head side than the external thread portion, and a fine diameter portion whose outer diameter is smaller than the inner diameter of the internal thread portion. The fine diameter portion is inserted into the through hole. When the third fastening bolt is loosened, it is configured such that the head side end of the external thread portion abuts against the internal thread portion of the third clamping piece.

[0020] Furthermore, the gate valve described above is ideally further provided with a valve box that houses the first valve plate and the second valve plate. The valve box has: a side wall around which the first and second valve plates surround the axis, and a top wall that is detachably mounted to the front end of the axial direction of the side wall. The side wall is provided with the first opening and the second opening facing each other. [The effects of the invention]

[0021] As explained above, according to the present invention, with the front end of the valve shaft directly clamped by a pair of valve plates, the pair of valve plates and the valve shaft are detachably fastened to each other, thereby detachably mounting the pair of valve plates to the valve shaft. Therefore, not only can it provide a gate valve with excellent operability during maintenance, but it can also suppress the weight around the valve plates and thus reduce various costs. Simple Explanation of the Diagram

[0022] [Figure 1] is a perspective view of a gate valve related to the first embodiment of the present invention. [Figure 2] is a plan view of the gate valve. [Figure 3] is a partial cross-sectional view of the gate valve, which corresponds to the arrow III-III shown in Figure 2. [Figure 4] is an enlarged cross-sectional view of part A in Figure 3. [Figure 5] is a cross-sectional view of the gate valve, which corresponds to the VV arrow shown in Figure 2. [Figure 6] is a perspective view of the gate valve when the second valve plate is replaced. [Figure 7] is a perspective view of the gate valve with the second valve plate removed from the valve shaft. [Figure 8] is a plan view of a gate valve related to the second embodiment of the present invention. [Figure 9] is a partial cross-sectional view of the gate valve, which corresponds to the arrow IX-IX shown in Figure 8. [Figure 10] is a partial cross-sectional view of the gate valve, which corresponds to the arrow XX in Figure 8. [Figure 11] is a partial cross-sectional view of the gate valve, which corresponds to the arrow XI-XI shown in Figure 8. [Figure 12] is an exploded perspective view of the support mechanism. [Figure 13] is a partial perspective view of the gate valve. [Figure 14] is a partial perspective view of the gate valve with the first valve plate removed. [Figure 15] is a partial perspective view of the gate valve with the second valve plate removed. [Figure 16] is a cross-sectional view of a gate valve related to the third embodiment of the present invention. [Figure 17] is an internal view of the gate valve. Implementation

[0023] [First Implementation Form]

[0024] The following describes the gate valve related to the present invention. The gate valve 10 is shown in Figures 1, 2 and 3, and is composed of: a valve shaft 17 extending in the vertical direction (axis L direction); a first valve plate 21 and a second valve plate 22 connected to the valve shaft 17; and an operating mechanism 24 that moves the first valve plate 21 and the second valve plate 22 through the valve shaft 17.

[0025] The operating mechanism 24 has two cylinders 25, 25 arranged parallel to each other on the left and right sides of the valve shaft 17. By means of these cylinders 25, the valve shaft 17 is moved to move the first valve plate 21 and the second valve plate 22.

[0026] The first valve plate 21 and the second valve plate 22 are arranged opposite each other in the front-to-back direction and extend in the left-to-right direction (longitudinal direction). These first and second valve plates 21 and 22 are generally rectangular plates. In this embodiment, the first valve plate 21 and the second valve plate 22 are elongated (rectangular) in the left-to-right direction when viewed from the front. Annular sealing members 21a and 22a are provided on the outer periphery of the sealing surfaces (outer surfaces) 21e and 22e on the respective outer sides of the first valve plate 21 and the second valve plate 22.

[0027] A valve shaft 17 is disposed between the first valve plate 21 and the second valve plate 22. The first valve plate 21 and the second valve plate 22 are detachably mounted on the valve shaft 17 by means of a fastening mechanism 30 in a state of abutting against the valve shaft 17. Furthermore, the two ends of the first valve plate 21 and the second valve plate 22 in the longitudinal direction are detachably fastened to each other by means of a support mechanism 50.

[0028] The valve shaft 17 extends upward (axially towards the front end) from the operating mechanism 24 and in the vertical direction (axis L direction). As shown in FIG3, a first side surface 17a and a second side surface 17b, which are quadrangular and facing away from each other across the axis L, are formed on both sides of the upper side of the valve shaft 17 in the front-rear direction. In this embodiment, the first side surface 17a and the second side surface 17b extend parallel to each other, such that the inner surface 21b facing away from the sealing surface 21e of the first valve plate 21 contacts the first side surface 17a, and the inner surface 22b facing away from the sealing surface 22e of the second valve plate 22 contacts the second side surface 17b. The first valve plate 21 and the second valve plate 22 are arranged parallel to each other across the valve shaft 17.

[0029] The fastening mechanism 30 for securing the first valve plate 21 and the second valve plate 22 to the valve shaft 17 is shown in Figures 2, 3, and 4. It includes: a first engaging recess 36 and a second engaging recess 45 opening at the center of the inner surfaces 21b and 22b of the first valve plate 21 and the second valve plate 22 in the longitudinal direction towards the axial front end; a first clamping piece 31, which is installed across the valve shaft 17 and the first valve plate 21 from the axial front end of the valve shaft 17, and can be detached from the first valve plate 21 and detachably fixed relative to the valve shaft 17; and a fastening mechanism 30, which is installed across the valve shaft 17 and the second valve plate 22 from the axial front end of the valve shaft 17. The installation includes a second clamping piece 40 that can be detached from the second valve plate 22 and fixed detachably from the valve shaft 17; a first fastening bolt 67 (first fastening member) and a second fastening bolt 71 (second fastening member) that respectively fix the first clamping piece 31 and the second clamping piece 40 to the upper end of the valve shaft 17; lower engaging recesses 26 and 27 (engaging portions, recesses) provided at the base end sides of the first valve plate 21 and the second valve plate 22; and a first protruding part 19 and a second protruding part 20 (engaged portions, protrusions) provided at the front end of the valve shaft 17 that engage with the lower engaging recesses 26 and 27 from the front end side of the valve shaft 17. Details regarding the first engaging recess 36 will be described later.

[0030] An upward-facing shaft end face 17c is formed at the upper end of the valve shaft 17. In this embodiment, the shaft end face 17c extends in the left-right direction, and a protruding strip 18 extending in the left-right direction and protruding upward is provided at the middle part of the shaft end face 17c in the front-back direction. A flat portion 18a extending parallel to the shaft end face 17c is formed on the upper part of the protruding strip 18, and a first inclined surface 18b and a second inclined surface 18c are formed on the front and rear sides of the protruding strip 18. The flat portion 18a has a plurality of internally threaded portions 70 (threaded holes) spaced apart in the left-right direction. The first fastening bolt 67 and the second fastening bolt 71, which are screwed into the first clamping piece 31 and the second clamping piece 40, are used to fasten the first valve plate 21 and the second valve plate 22 to the valve shaft 17 by means of the first and second clamping pieces 31 and 40 fixed on the protruding strip 18. Details of the first fastening bolt 67 and the internal thread 70 are described below.

[0031] The first clamping plate 31, as shown in FIG4, has: a first clamping main body 32 fixed to the shaft end face 17c (protrusion 18) through a first fastening bolt 67 (see FIG1), and a first engaging protrusion 34 formed on the side of the first valve plate 21 of the first clamping main body 32 and protruding downward to engage the first valve plate 21. The first clamping main body 32 is formed into a plate shape extending in the front-rear direction. A through hole 32a is provided on the side of the second valve plate 22 (rear side) of the first clamping main body 32 for the first fastening bolt 67 to be inserted. The external thread 68a of the first fastening bolt 67 inserted into this through hole 32a is screwed into the internal thread 70 (first fastening member) of the valve shaft 17.

[0032] On the side of the second valve plate 22 of the first clamping main body 32, a downwardly protruding main body locking claw (first locking claw) 33 is formed. On the inner surface of the main body locking claw 33, a third inclined surface 33a is formed extending along the second inclined surface 18c of the protrusion 18. That is, the third inclined surface 33a is inclined to the rear (outer side) as it faces downward. Therefore, when the first clamping main body 32 is fastened to the protrusion 18 with the first fastening bolt 67 while the third inclined surface 33a is in contact with the second inclined surface 18c, the force component (pushing force) of the force acting on the second inclined surface 18c from the third inclined surface 33a causes the third inclined surface 33a to come into close contact with the second inclined surface 18c, thereby fastening the first clamping piece 31 to the valve shaft 17.

[0033] The first engaging protrusion 34, located on the first valve plate 21 side of the first clamping main body 32, has a fourth inclined surface 34a that slopes outwards from the lower side. In this embodiment, as shown in FIG2, the first clamping piece 31 comprises two first clamping main bodies 32 spaced apart in the left-right direction, and a connecting portion 35 connecting the front sides of the two first clamping main bodies 32 to each other. Furthermore, at the lower portion of the first valve plate 21 side of each of the two first clamping main bodies 32 and the connecting portion 35, the first engaging protrusion 34 (see FIG4) extends from one end of the first clamping piece 31 in the left-right direction to the other end. Between the two first clamping main bodies 32, a second clamping main body 41 of the second clamping piece 40 (described later) is disposed.

[0034] The first valve plate 21 abutting the first clamping piece 31 is shown in Figures 2 and 4, and has a first engaging recess 36 for engaging the first engaging protrusion 34 in a forward-facing recess. The first engaging recess 36 has a first engaging groove 36a at its bottom that is recessed downward from the front side than the inner surface 21b. In this embodiment, the first engaging recess 36 is formed in the upper part of the inner surface 21b of the first valve plate 21 and in the middle part in the left-right direction. The first engaging recess 36 opens inward and extends upward, opening at the upper end of the first valve plate 21. In the first engaging groove 36a of the first engaging recess 36, a fifth inclined surface 36b is formed that slopes upward toward the valve shaft 17 side.

[0035] Therefore, when the first clamping piece 31 is fastened to the upper end of the valve shaft 17 with the first fastening bolt 67, and the fourth inclined surface 34a of the first clamping piece 31 is pressed against the fifth inclined surface 36b of the first engaging recess 36, the inward component of the force acting on the fourth inclined surface 34a can be used to fasten the upper part of the first valve plate 21 to the valve shaft 17 (first side surface 17a).

[0036] Furthermore, the lower end (base end) of the first valve plate 21 is engaged with the front end of the valve shaft 17 from the front end side. Specifically, as shown in FIG3, a lower engagement recess (recess) 26 is formed in the middle of the inner side of the bottom surface 21c of the first valve plate 21 in the left-right direction, located below the first engagement recess 36 and extending in the left-right direction. Inside this lower engagement recess 26, a sixth inclined surface 26a is formed that slopes outward from the top, and the first protrusion 19 (engaged portion, protrusion) of the valve shaft 17 is inserted into this lower engagement recess 26. The first protrusion 19 is formed on the front stage portion 17d extending forward from the lower end of the first side surface portion 17a of the valve shaft 17. The first protrusion 19 extends in the left and right direction on the front stage 17d, and a seventh inclined surface 19a is formed on the inner side of the first protrusion 19, which slopes outwards towards the upper side.

[0037] Therefore, when the first clamping piece 31 is fixed to the upper end of the valve shaft 17 by the first fastening bolt 67, the first valve plate 21 is pushed downward by the component of the force of the fourth inclined surface 34a of the first clamping piece 31 pressing against the fifth inclined surface 36b of the first valve plate 21. As a result, the sixth inclined surface 26a formed on the lower part of the first valve plate 21 is pressed against the seventh inclined surface 19a of the valve shaft 17, and the component of the reverse force from the seventh inclined surface 19a makes the lower side of the first valve plate 21 closely connected and fastened to the valve shaft 17 (first inclined surface 17a).

[0038] In this way, the first clamping piece 31 is fixed to the upper end of the valve shaft 17, and can be installed with the first valve plate 21 in close contact with the first side surface 17a of the valve shaft 17.

[0039] The second clamping piece 40, as shown in FIG. 4, has a second clamping main body 41 formed similarly to the first clamping piece 31, which is fixed to the protrusion 18 formed on the shaft end face 17c by a second fastening bolt 71, and a second engaging protrusion 43 protruding downward from the second valve plate 22 side of the second clamping main body 41 and engaging the second valve plate 22. The second clamping main body 41 is formed into a plate shape extending in the front-rear direction. At the end of the second clamping main body 41 on the first valve plate 21 side, a through hole 41a through which the second fastening bolt 71 is inserted is provided. The second fastening bolt 71, which is inserted through this through hole 41a, is screwed into the internal thread 70 of the valve shaft 17. Furthermore, in this embodiment, the first fastening bolt 67 and the second fastening bolt 71 are hexagon socket head cap screws.

[0040] At the end of the second clamping main body 41 on the side (front side) of the first valve plate 21, a downwardly protruding main body locking claw 42 is formed. On the inner surface of the main body locking claw 42, an eighth inclined surface 42a is formed, extending along the first inclined surface 18b of the protrusion 18 formed at the upper end of the valve shaft 17. That is, the eighth inclined surface 42a is inclined towards the front (outer side) as it descends. Therefore, when the eighth inclined surface 42a is in contact with the first inclined surface 18b, and the second clamping main body 41 is fixed to the protrusion 18 by the second fastening bolt 71, the force component of the force acting from the eighth inclined surface 42a on the first inclined surface 18b causes the eighth inclined surface 42a to closely contact the first inclined surface 18b, thus fastening the second clamping piece 40 to the valve shaft 17.

[0041] The second engaging protrusion 43 has a ninth inclined surface 43a formed on its inner side, which slopes downwards and outwards (rearwards). In this embodiment, as shown in FIG2, the second clamping piece 40 has two second clamping main bodies 41 spaced apart in the left-right direction, and a connecting portion 44 connecting the two second clamping main bodies 41 to each other on the second valve plate 22 side (rearwards). Furthermore, at the lower part of the two second clamping main bodies 41 and the connecting portion 44 on the second valve plate 22 side, the second engaging protrusion 43 (see FIG4) extends from one end of the second clamping piece 40 in the left-right direction to the other end. Between the two second clamping main bodies 41, a first clamping main body 32 of the first clamping piece 31 is disposed.

[0042] As shown in Figures 2 and 4, a second engaging recess 45 is formed on the inner surface 22b of the second valve plate 22 that contacts the second clamping piece 40, for engaging the second engaging protrusion 43. The second engaging recess 45 has a second engaging groove 45a at its bottom that is recessed downwards from a position further rearwards from the inner surface 22b. In this embodiment, the second engaging recess 45 is formed on the upper part of the inner surface 22b of the second valve plate 22 in the middle of the left-right direction. The second engaging recess 45 opens inwards and extends upwards at the upper end of the second valve plate 22. In the second engaging groove 45a of the second engaging recess 45, a 10th inclined surface 45b is formed that slopes upwards towards the valve shaft 17.

[0043] Therefore, when the second clamping piece 40 is fastened to the upper end (protruding part 18) of the valve shaft 17 by the second fastening bolt 71, and the 9th inclined surface 43a of the second clamping piece 40 is pressed against the 10th inclined surface 45b of the second engaging recess 45, the upper part of the second valve plate 22 can be tightly and fastened to the valve shaft 17 (second side part 17b) by means of the inward component of the force acting on the 10th inclined surface 45b.

[0044] Furthermore, the lower end (base end) of the second valve plate 22 is engaged with the front end of the valve shaft 17 from the front end side. Specifically, as shown in FIG3, a lower engagement recess 27 is formed below the second engagement recess 45 on the inner side of the bottom surface 22c of the second valve plate 22, which is recessed upward. On the inner side of this lower engagement recess 27, an 11th inclined surface 27a is formed that slopes outward as it rises upward. A second protrusion 20 (engaged portion, protrusion) provided on the valve shaft 17 is inserted into this lower engagement recess 27. The second protrusion 20 is formed on the rear section 17e that extends rearward from the lower end of the second side surface 17b of the valve shaft 17. The second protrusion 20 extends in the left-right direction on the rear section 17e, and on the inner side of the second protrusion 20, a 12th inclined surface 20a that slopes outward as it rises upward is formed.

[0045] Therefore, when the second clamping piece 40 is fixed to the upper end of the valve shaft 17 by the second fastening bolt 71, the second valve plate 22 is pushed downward by the component of the force of the 9th inclined surface 43a of the second clamping piece 40 pressing against the 10th inclined surface 45b of the second valve plate 22. Thus, the 11th inclined surface 27a formed on the lower part of the second valve plate 22 is pressed against the 12th inclined surface 20a of the valve shaft 17, and the lower side of the second valve plate 22 is tightly and fastened to the valve shaft 17 (second side surface 17b) by the component of the reverse force from the 12th inclined surface 20a.

[0046] In this way, the second clamping piece 40 is fixed to the upper end of the valve shaft 17, so that the second valve plate 22 can be installed in close contact with the valve shaft 17.

[0047] Here, the first and second fastening bolts 67 and 71 and the internal thread portion 70 will be described. Since the first and second fastening bolts 67 and 71 are identical, the second fastening bolt 71 will be described specifically. The second fastening bolt 71, as shown in FIG4, comprises: a shaft portion 68 extending along the axis L; a head 69 provided at the upper end of the shaft portion 68; and an external thread portion 68a formed on the lower periphery of the shaft portion 68. Above the external thread portion 68a in the shaft portion 68, a small-diameter portion (unthreaded portion) 68b without the external thread portion 68a is provided. The small-diameter portion 68b is smaller than the outer diameter of the external thread portion 68a and smaller than the internal thread portion 70 provided on the inner surface of the through hole 41a of the second clamping piece 40. That is, the internal thread portion 70 is provided on the upper part of the inner surface of the hole portion 18d extending downward from the flat portion 18a of the protruding bar portion 18 and the inner surface of the through hole 41a of the second clamping body portion 41. Furthermore, the first clamping body portion 32 is also provided with the internal thread portion 70 in the same way as the second clamping body portion 41.

[0048] Rotate the second fastening bolt 71 toward one side of the shaft so that the external thread 68a engages with the internal thread 70. Then, with the head 69 of the second fastening bolt 71 pressed against the upper part of the second clamping piece 40, the second clamping piece 40 can be fixed to the upper end of the valve shaft 17.

[0049] On the other hand, when the second clamping piece 40 is loosely fastened relative to the valve shaft 17, the second fastening bolt 71 is rotated to the other side around the shaft, causing the shaft portion 68 to move upward along the internal thread portion 70. At this time, as the narrow diameter portion 68b moves within the internal thread portion 70 of the second clamping piece 40, the upper end of the external thread portion 68a abuts against the lower end of the internal thread portion 70 of the second clamping piece 40, pushing the second clamping piece 40 upward. Therefore, with the upward movement of the second fastening bolt 71, the second engaging protrusion 43 of the second clamping piece 40 is disengaged from the second engaging groove 45a of the second engaging recess 45, releasing the engagement of the second clamping piece 40 with respect to the second valve plate 22.

[0050] Here, the axial length of the external thread portion 68a needs to be greater than the required axial movement distance when the second engaging protrusion 43 is disengaged from the second engaging groove 45a. Therefore, when the engagement with the second clamping piece 40 relative to the second valve plate 22 is released, since the external thread portion 68a is engaged with the internal thread portion 70 on the valve shaft 17 side, the second fastening bolt 71 can be prevented from disengaging from the valve shaft 17 and falling off or getting lost.

[0051] Furthermore, the third fastening bolt 72 and the internal thread portion 70 provided in the support mechanism 50 shown in Figure 5 are the same as the first and second fastening bolts 67, 71 and the internal thread portion 70 provided in the fastening mechanism 30. Therefore, the third fastening bolt 72 and the internal thread portion 70 of the support mechanism 50 are given the same symbol and their description is omitted.

[0052] Next, the support mechanism 50 will be described. As shown in Figures 5 and 6, the support mechanism 50 includes: a third engaging recess 64 and a fourth engaging recess 66 disposed on the inner surfaces 21b and 22b of the first valve plate 21 and the second valve plate 22; a support platform 51 disposed between the left and right sides of the first valve plate 21 and the second valve plate 22; a third clamping piece 60 disposed at the upper end of the support platform 51 and engaging the third engaging recess 64 and the fourth engaging recess 66; and the third clamping piece 60 can... The third fastening bolt 72 (third fastening member) is fixed to the support platform 51; the lower engaging recesses (base end engaging portions, recesses) 28 and 29 are provided at the base end ends of both ends of the first valve plate 21 and the second valve plate 22 in the long direction; and the third protrusion 53 and the fourth protrusion 54 (base end engaging protrusions, protrusions) are provided on the support platform 51 and engage the lower engaging recesses 28 and 29 from the front end of the support platform 51.

[0053] The support platform 51 has an upwardly planar support end face 51c at its upper end, forming a cuboid shape extending in the vertical direction. On both sides of the support platform 51 in the front-rear direction, there are first contact surfaces 51a and second contact surfaces 51b that contact the inner surfaces 21b and 22b of the first valve plate 21 and the second valve body 22, respectively. A downwardly extending hole 55 is provided in the center of the support end face 51c. An internal thread 70 (screw hole) is formed on the inner surface of this hole 55. This internal thread 70 is screwed into a third fastening bolt 72 for fixing the third clamping piece 60 to the support platform 51.

[0054] The lower ends (base end ends) of the first and second valve plates 21 and 22 are engaged with the support platform 51 from the front end side. Specifically, as shown in FIG. 5, a front section 51d protruding forward and extending in the left and right direction is formed on the lower part of the first contact surface 51a of the support platform 51. A third protruding strip 53 protruding upward and extending in the left and right direction is formed at the tip end (front end) of the front section 51d. A 13th inclined surface 53a is formed on the inner surface of the third protruding strip 53, which is inclined outward (front) as it is upward. This third protruding strip 53 is inserted into the lower engaging recess 28 formed on the bottom surface of the first valve plate 21, and the lower end of the first valve plate 21 is engaged with the support platform 51 from the front end side.

[0055] The lower engaging recess 28 is formed on both sides of the bottom surface 21c of the first valve plate 21 in the left-right direction and extends in the left-right direction. The outer ends of the lower engaging recess 28 in the left-right direction are open at the ends of the first valve plate 21 in the left-right direction. That is, the lower engaging recess 28 opens downward and at the ends of the first valve plate 21 in the left-right direction. On the inner side of the lower engaging recess 28, a 14th inclined surface 28a is formed that slopes outward (front side) upward.

[0056] On the other hand, a rear section 51e is formed at the lower part of the second contact surface 51b of the support platform 51, protruding towards the second valve plate 22 (rear side) and extending in the left-right direction. At the outer end of the rear section 51e, a fourth protruding strip 54 is formed, protruding upward. The inner surface of this fourth protruding strip 54 has a 15th inclined surface 54a that slopes outward (rear side) as it rises upward. This fourth protruding strip 54 is inserted into the lower engaging recess 29 formed on the bottom surface 22c of the second valve plate 22, engaging the lower end of the second valve plate 22 from the front end side of the support platform 51 with the support platform 51.

[0057] The lower engaging recess 29 is formed on both sides of the bottom surface 22c of the second valve plate 22 in the left-right direction and extends in the left-right direction. The outer ends of the lower engaging recess 29 in the left-right direction are open at the ends of the second valve plate 22 in the left-right direction. That is, the lower engaging recess 29 opens downward and at the ends of the second valve plate 22 in the left-right direction. On the inner side of the lower engaging recess 29, a 16th inclined surface 29a is formed that slopes outward (rearward) as it moves upward.

[0058] Next, the third clamping piece 60 will be described. As shown in FIG5, the third clamping piece 60 has: a third clamping main body 61 fixed to the support end face 51c of the support platform 51 by the third fastening bolt 72 and extending in the front-rear direction with the third fastening bolt 72 as the center; and a third engaging protrusion 62 and a fourth engaging protrusion 63 formed at both ends in the front-rear direction of the third clamping main body 61 and protruding toward the side of the first valve plate 21 and the side of the second valve plate 22 to engage with the first valve plate 21 and the second valve plate 22.

[0059] The third clamping main body 61 is plate-shaped and extends in the front-rear direction. The front-rear sides of the third clamping main body 61 extend outwards from the first contact surface 51a and the second contact surface 51b of the support platform 51, respectively. At the center of the third clamping main body 61 in the front-rear direction, a through hole 61a extending in the vertical direction is provided, and an internal thread (screw hole) 70 is provided on the inner surface of this through hole 61a. Furthermore, the support end face 51c of the support platform 51 is provided with a hole 55 extending downwards, and an internal thread (screw hole) 70 is provided on the inner surface of this hole 55. That is, the internal thread 70 is provided on the inner surfaces of both the through hole 61a and the hole 55. In this embodiment, the internal thread 70 provided on the inner surface of the through hole 61a extends from the lower part to the upper part of the inner surface of the through hole 61a.

[0060] The third engaging protrusion 62 protrudes downward from the front end of the third clamping main body 61, and a 17th inclined surface 62a is formed on its inner side, which slopes outward as it descends. The inner surface 21b of the first valve plate 21, which is in contact with this third engaging protrusion 62, has a third engaging recess 64 that is recessed forward and engages the third engaging protrusion 62.

[0061] The third engaging recess 64 has a third engaging groove 64a recessed downward at its bottom, and an 18th inclined surface 64b that slopes upward toward the valve shaft 17 is formed in the third engaging groove 64a. In this embodiment, the third engaging recess 64 extends to the left and right sides of the first valve plate 21 and opens at both ends, and also opens at the top (see FIG6).

[0062] As shown in Figure 5, when the third clamping piece 60 is fixed to the upper end of the support platform 51 by the third fastening bolt 72, the 17th inclined surface 62a of the third engaging protrusion 62 presses against the 18th inclined surface 64b of the third engaging recess 64. By means of the component force acting on the 18th inclined surface 64b, the upper part of the first valve plate 21 is tightly connected and fastened to the support platform 51.

[0063] Furthermore, when the third clamping piece 60 is fixed to the upper end of the support platform 51 by the third fastening bolt 72, the first valve plate 21 is pushed downward through the third clamping piece 60. Therefore, the 14th inclined surface 28a formed on the lower part of the first valve plate 21 is pressed against the 13th inclined surface 53a of the valve plate 17, and the lower side (base end) of the first valve plate 21 is tightly and fastened to the support platform 51 by the component force of the reverse force from the 13th inclined surface 53a.

[0064] On the other hand, the fourth engaging protrusion 63 of the third clamping piece 60 protrudes downward from the rear end of the third clamping main body 61, and a 19th inclined surface 63a is formed on its inner side, which slopes outward as it moves downward. On the inner surface of the second valve plate 22 that abuts against the fourth engaging protrusion 63, a fourth engaging recess 66 is formed that is recessed to the rear and engages the fourth engaging protrusion 63.

[0065] The fourth engaging recess 66 has a fourth engaging groove 66a recessed downward at its bottom, and a second 21 inclined surface 66b that slopes upward toward the valve shaft 17 is formed in the fourth engaging groove 66a. In this embodiment, the fourth engaging recess 66 extends to the left and right sides of the second valve plate 22, opening at both ends and at the top.

[0066] Therefore, as shown in Figure 5, the third clamping piece 60 is fixed to the upper end of the support platform 51 by the third fastening bolt 72. When the 19th inclined surface 63a of the fourth engaging protrusion 63 presses against the 21st inclined surface 66b of the fourth engaging recess 66, the upper part of the second valve plate 22 is tightly connected and fastened to the support platform 51 by the component force of the force acting on the 21st inclined surface 66b.

[0067] Furthermore, when the third clamping piece 60 is fixed to the upper end of the support platform 51 by the third fastening bolt 72, the second valve plate 22 is pushed downward through the third clamping piece 60. Therefore, the 16th inclined surface 29a formed on the lower part of the second valve plate 22 presses against the 15th inclined surface 54a of the support platform 51, and the lower side of the second valve plate 22 is tightly and securely fixed to the support platform 51 by the component of the reverse force from the 15th inclined surface 54a. In this way, the third clamping piece 60 can be fixed to the upper end of the support platform 51 by the third fastening bolt 72, and the first valve plate 21 and the second valve plate 22 are fastened together through the support platform 51.

[0068] Furthermore, as described above, the third engaging recess 64 and the fourth engaging recess 66 formed on the upper parts of the first valve plate 21 and the second valve plate 22, respectively, and the lower engaging recesses 28 and 29 formed on the lower parts extend outward in the left and right directions and open at their outer ends in the left and right directions. Therefore, when the third clamping piece 60 is engaged with the third engaging recess 64 and the fourth engaging recess 66, and the third protrusion 53 and the fourth protrusion 54 are engaged with the lower engaging recesses 28 and 29, the pressing state of the third clamping piece 60 relative to the first valve plate 21 and the second valve plate 22 can be eased when the tightening of the third fastening bolt 72 is loosened. Therefore, when the support platform 51 pushes outward in the left and right direction relative to the first valve plate 21 and the second valve plate 22, the third engaging protrusion 62 and the fourth engaging protrusion 63 can slide along the third engaging recess 64 and the fourth engaging recess 66, and the third protruding strip 53 and the fourth protruding strip 54 can slide along the lower engaging recesses 28 and 29, thereby removing the support mechanism 50 from the first and second valve plates 21 and 22.

[0069] Next, the description will address the scenario where either the first valve plate 21 or the second valve plate 22 mounted on the valve shaft 17 is removed. This embodiment is described in the case where the second valve plate 22 is removed. As shown in Figure 6, firstly, in the support platform 51 of either of the two support platforms 51 mounted on the first valve plate 21 and the second valve plate 22, the third fastening bolt 72 that fixes the third clamping piece 60 is rotated to ease the pressing state of the third clamping piece 60 relative to the first valve plate 21 and the second valve plate 22. Therefore, the pressing state of the third clamping piece 60 relative to the third engaging protrusion 62 and the fourth engaging protrusion 63 relative to the third engaging recess 64 and the fourth engaging recess 66 is eased, and the support platform 51 becomes a state in which it can slide relative to the first valve plate 21 and the second valve plate 22. Furthermore, the other support platform 51 also becomes a state in which it can slide, just like the first support platform 51.

[0070] Furthermore, one of the support platforms 51 and the third clamping piece 60 are slidably removed from the first valve plate 21 and the second valve plate 22 in a left-right outward direction. Similarly, the other support platform 51 is slidably removed from the first valve plate 21 and the second valve plate 22 in a left-right outward direction.

[0071] Furthermore, by rotating the second fastening bolt 71 inserted into the second clamping piece 40, the engagement of the second fastening bolt 71 with respect to the internal thread 70 of the valve shaft 17 is loosened, and the second clamping piece 40 is removed from the valve shaft 17. Then, when the second valve plate 22 is pulled upwards, the second protrusion 20 of the valve shaft 17 (see Figure 3) disengages from the lower engagement recess 27 (see Figure 3) on the bottom surface of the second valve plate 22, and the fourth protrusion 54 of the valve shaft 17 (see Figure 5) disengages from the lower engagement recess 29 (see Figure 5), thus removing the second valve plate 22 from the valve shaft 17. Therefore, as shown in Figure 7, the gate valve 10 is in a state where the second valve plate 22 is removed and only the first valve plate 21 is installed.

[0072] Next, the installation of the second valve plate 22 onto the valve shaft 17 will be described. First, as shown in Figures 3 and 5, the second protrusion 20 of the valve shaft 17 is inserted into the lower engaging recess 27 of the second valve plate 22, and the fourth protrusion 54 is inserted into the lower engaging recess 29. Then, the second valve plate 22 is tilted towards the valve shaft 17, so that the inner surface 22b of the second valve plate 22 contacts the second side surface 17b of the valve shaft 17. With the second engaging protrusion 43 of the second clamping piece 40 inserted into the second engaging recess 45, the second clamping piece 40 is fixed to the upper end of the valve shaft 17 by the second fastening bolt 71. As a result, the second valve plate 22 is securely fastened to the valve shaft 17 in a close contact.

[0073] Furthermore, with the third fastening bolt 72 of the third clamping piece 60, which is inserted through the upper ends of the two support platforms 51, 51 respectively, loosened, as shown in Figures 5 and 6, the support platform 51 is moved from the outer end of the first valve plate 21 and the second valve plate 22 in the left and right directions toward the valve shaft 17 side. The third protrusion 53 and the fourth protrusion 54 of the support platform 51 are inserted into the lower engagement recesses 28 and 29 formed in the lower part of the first valve plate 21 and the second valve plate 22, and the third engagement protrusion 62 and the fourth engagement protrusion 63 of the third clamping piece 60 are inserted into the third engagement recesses 64 and the fourth engagement recesses 66 of the first valve plate 21 and the second valve plate 22.

[0074] Furthermore, one of the support plates 51 is slidably moved toward the valve shaft 17, moving relative to the first valve plate 21 and the second valve plate 22 to a predetermined position. The third fastening bolt 72 is then securely tightened relative to the third clamping piece 60, and the first valve plate 21 and the second valve plate 22 are fastened to each other in the left-right direction via the support platform 51. Similarly, the other support platform 51 is used to fasten the other side of the first valve plate 21 and the second valve plate 22 to each other in the left-right direction. In this way, the second valve plate 22 is mounted relative to the valve shaft 17.

[0075] As described above, the gate valve 10 of this embodiment is positioned such that the front end of the valve shaft 17 is directly sandwiched between the first valve plate 21 and the second valve plate 22, thereby detachably securing the pair of valve plates 21, 22 and the valve shaft 17 to each other, and thus detachably mounting the pair of valve plates 21, 22 relative to the valve shaft 17. Therefore, it not only provides excellent operability during maintenance of the valve plates 21, 22, but also reduces the weight around the valve plates 21, 22, providing a gate valve 10 that can suppress various costs.

[0076] Furthermore, the gate valve 10 of this embodiment allows for the loosening or tightening of the first and second fastening bolts 67 and 71 inserted into the first clamping plate 31 and the second clamping plate 40, enabling the detachment of the first valve plate 21 and the second valve plate 22 from the valve shaft 17. Moreover, the gate valve 10 of this embodiment does not require the removal of the third clamping plate 60 or the third fastening bolt 72 from the support platform 51; simply tightening or loosening the third fastening bolt 72 is sufficient to remove the support platform 51 from the first valve plate 21 and the second valve plate 22, or to connect the first valve plate 21 and the second valve plate 22 to each other. Therefore, the gate valve 10 of this embodiment allows for simple fixing or removal of the first valve plate 21 and the second valve plate 22 from the valve shaft 17, improving the operability of valve plate 21 and 22 during maintenance.

[0077] Furthermore, the first, second, and third fastening bolts 67, 71, and 72 that fasten the first clamping piece 31, the second clamping piece 40, and the third clamping piece 60 are configured to prevent the clamping pieces 31, 40, and 60 from being removed, and to allow the clamping pieces 31, 40, and 60 to move upward together with the fastening bolts 67, 71, and 72 when the fastening bolts 67, 71, and 72 are rotated in a direction of gentle tightening. Therefore, when the clamping pieces 31, 40, and 60 are released from their locking position, the fastening bolts 67, 71, and 72 can be prevented from falling off or falling out, thus making the replacement of the first valve plate 21 and the second valve plate 22 easier.

[0078] [Second Implementation] Next, a second embodiment of the gate valve 10 related to the present invention will be described. In the second embodiment, the differences from the first embodiment described above will be mainly explained, and the same symbols will be assigned to embodiments that are the same as those in the first embodiment, and their descriptions will be omitted.

[0079] The protruding part 18 provided on the shaft end face 17c of the valve shaft 17 is shown in Figures 8, 9 and 10. Two protruding parts are provided at intervals in the left and right directions. One part is used to fix the first clamping piece 31, and the other part is used to fix the second clamping piece 40.

[0080] The first clamping piece 31 and the second clamping piece 40 are rotatably mounted on the upper end of the valve shaft 17, and the third clamping piece 60 is rotatably mounted on the upper end of the support platform 51. Specifically, the first clamping piece 31 is configured to rotate around the axis of the first fastening bolt 67 when loosely fixed to the valve shaft 17; the second clamping piece 40 is configured to rotate around the axis of the second fastening bolt 71 when loosely fixed to the valve shaft 17; and the third clamping piece 60 is configured to rotate around the axis of the third fastening bolt 72 when loosely fixed to the support platform 51.

[0081] More specifically, the first engaging recess 36 formed on the inner surface 21b of the first valve plate 21 opposite to the first clamping piece 31 is, as shown in Figures 8 and 9, a first extended recess 36c in which the first engaging protrusion 34 (front end) on the first valve plate 21 side of the first clamping piece 31 does not contact the first engaging recess 36 when the first clamping piece 31 rotates around the axis of the first fastening bolt 67. In this embodiment, the first extended recess 36c is formed from the bottom to the top of the first engaging recess 36, and in plan view, it is formed as an arc shape that extends radially outward more than the rotation trajectory of the front end of the first clamping piece 31 when it rotates around the axis of the first fastening bolt 67.

[0082] Furthermore, when the first clamping piece 31 is rotated, the first clamping piece and the second clamping piece are arranged with a predetermined gap Y in the left-right direction, so that the rear end of the first clamping piece 31 does not contact the second clamping piece 40 arranged adjacent to it in the left-right direction. Therefore, the first clamping piece 31 can rotate around the axis of the first fastening bolt 67 without contacting the second clamping piece 40. Also, the first clamping piece 31 rotates freely around the axis of the first fastening bolt 67 between the engagement position P1 (see FIG. 8) where the first engaging protrusion 34 engages with the first engaging recess 36 and the disengagement position P2 (see FIG. 14) where the first engaging protrusion 34 disengages from the first engaging recess 36. When the first clamping piece 31 rotates toward the disengagement position P2, it moves within the gap 47 (see FIG. 8) between the first valve plate 21 and the second valve plate 22.

[0083] Furthermore, the second engaging recess 45 formed on the inner surface 22b of the second valve plate 22 opposite to the second clamping piece 40 is shown in Figures 8 and 10. When the second clamping piece 40 rotates around the axis of the second fastening bolt 71, the second extended recess 45c, which has a second engaging protrusion 43 (front end) on the second valve plate 22 side of the second clamping piece 40, does not contact the second engaging recess 45. In this embodiment, the second extended recess 45c is formed from the middle position in the vertical direction of the second engaging recess 45 to the upper end, and in plan view, it is formed to be an arc shape that passes radially outward more than the rotation trajectory of the front end of the second clamping piece 40 when it rotates around the axis of the second fastening bolt 71. Therefore, the second clamping piece 40 can rotate without contacting the first clamping piece 31. Furthermore, the second clamping piece 40, like the first clamping piece 31, freely rotates around the axis of the second fastening bolt 71 between the engagement position P1 (see Figure 8) where the second engaging protrusion 43 engages with the second engaging recess 45 and the disengagement position P2 (see Figure 15) where the second engaging protrusion 43 disengages from the second engaging recess 45. When the second clamping piece 40 rotates toward the disengagement position P2, it moves within the gap 47 (see Figure 8) between the first valve plate 21 and the second valve plate 22.

[0084] Furthermore, the third engaging recess 64 and the fourth engaging recess 66 formed on the inner surfaces 21b and 22b of the first valve plate 21 and the second valve plate 22 opposite to the third clamping piece 60 are shown in Figures 8 and 11, and have a third extended recess 64d and a fourth extended recess 66d that are recessed outward in the front-rear direction. That is, the third engaging recess 64 and the fourth engaging recess 66 have: a state in which the third engaging protrusion 62 and the fourth engaging protrusion 63 of the third clamping piece 60 are disengaged upward from the third engaging groove 64a and the fourth engaging groove 66a, and when the third clamping piece 60 rotates around the axis of the first fastening bolt 67, the third engaging protrusion 62 (front end) of the third clamping piece 60 is recessed without contacting the third engaging recess 64, and the fourth engaging protrusion 63 (front end) of the third clamping piece 60 is recessed without contacting the fourth engaging recess 66, and the fourth engaging protrusion 63 (front end) of the third clamping piece 60 is recessed without contacting the fourth engaging recess 66.

[0085] The third clamping piece 60, as shown in Figures 8, 12, and 14, has a protruding piece 61b that protrudes from one side 61c of the third clamping main body 61. The front end of the protruding piece 61b has a fifth engaging protrusion 65 that engages with the third engaging recess 64 and the fourth engaging recess 66. That is, the third clamping piece 60 has a fifth engaging protrusion 65 in addition to the third engaging protrusion 62 and the fourth engaging protrusion 63. The third engaging protrusion 62 and the fourth engaging protrusion 63 are arranged radially on both sides of the rotation center of the third fastening bolt 72, as shown in the plane. The fifth engaging protrusion 65 is arranged at a position offset by 90° from the axis of the first fastening bolt 67 relative to the third engaging protrusion 62 and the fourth engaging protrusion 63. In addition, the third engaging protrusion 62, the fourth engaging protrusion 63 and the fifth engaging protrusion 65 are arranged at positions with the same rotation radius r relative to the rotation center of the third clamping piece 60.

[0086] As shown in FIG8, the third clamping piece 60 is engaged with the third engaging protrusion 62 and the fourth engaging protrusion 63 in the third engaging recess 64 and the fourth engaging recess 66. For example, when the third clamping piece 60 is rotated to release the engagement of the first valve plate 21, the engagement of the second valve plate 22 is also released. Therefore, a fifth engaging protrusion 65 is provided at a position offset by 90° from the third engaging protrusion 62 and the fourth engaging protrusion 63 around the axis. When the engagement of the first valve plate 21 is released, the fifth engaging protrusion 65 is engaged with the fourth engaging recess 66, and the third clamping piece 60 can be engaged with the second valve plate 22 (see FIG14).

[0087] However, as shown in Figure 9, the first side portion 17a and the second side portion 17b of the valve shaft 17 are provided with positioning pins 74a and 74b protruding outward in the front-rear direction. In this embodiment, positioning pin 74a is fitted into the positioning groove 21d of the first valve plate 21, and positioning pin 74b is fitted into the positioning groove 22d of the second valve plate 22. Positioning pin 74a is located at the lower part of the first side portion 17a, and positioning pin 74b is located at the lower part of the second side portion 17b. Positioning grooves 21d and 22d are open on the bottom surfaces of the first valve plate 21 and the second valve plate 22, respectively, and extend in a straight line upward from the valve shaft 17 side opening. Therefore, by inserting positioning pin 74a into positioning groove 21d, the first valve plate 21 can be positioned in the left-right direction relative to the valve shaft 17. Furthermore, by inserting positioning pin 74b into positioning groove 22d, the second valve plate 22 can be positioned in the left-right direction relative to the valve shaft 17.

[0088] Next, the case where either the first valve plate 21 or the second valve plate 22 installed on the valve shaft 17 is removed will be described. In this embodiment, the case where the first valve plate 21 is removed will be described first. As shown in FIG11, firstly, the third fastening bolts 72 of the third clamping pieces 60 respectively installed on the two support platforms 51 are rotated in a loosening direction. And, with the rotation of the third fastening bolts 72, the third clamping pieces 60 move upward, disengaging the third engaging protrusion 62 from the third engaging groove 64a of the third engaging recess 64, and disengaging the fourth engaging protrusion 63 from the fourth engaging groove 66a of the fourth engaging recess 66. Furthermore, as shown in Figure 14, in the planar display, the two third clamping pieces 60, 60 arranged on the left and right rotate around the axis respectively, disengaging the third engaging protrusion 62 from the third engaging recess 64, disengaging the fourth engaging protrusion 63 from the fourth engaging recess 66, and locking the fifth engaging protrusion 65 into the fourth engaging recess 66.

[0089] Furthermore, the first fastening bolt 67 of the first clamping piece 31, which is mounted on the valve shaft 17 shown in FIG. 9, is rotated in a loosening direction. With the rotation of the first fastening bolt 67, the first clamping piece 31 moves upward, disengaging the first engaging protrusion 34 from the first engaging groove 36a of the first engaging recess 36. Also, as shown in FIG. 14, in a plan view, the first clamping piece 31 is rotated clockwise, disengaging the first engaging protrusion 34 from the first engaging recess 36. As a result, when the first valve plate 21 is lifted upward relative to the valve shaft 17, the first valve plate 21 can be removed from the valve shaft 17 and the support platform 51.

[0090] Next, the case where the first valve plate 21 is mounted on the valve shaft 17 will be described. First, as shown in FIG. 14, the first valve plate 21 is positioned opposite the second valve plate 22 with its inner surface 21b facing the valve shaft 17. The first protrusion 19 of the valve shaft 17 is inserted into the lower engagement recess 26 of the first valve plate 21 (see FIG. 9), and simultaneously, the third protrusions 53, located at the lower parts of the two support platforms 51, are inserted into the lower engagement recess 28 of the first valve plate 21 (see FIG. 11). The inner surface 21b of the first valve plate 21 is brought into contact with the first side surface 17a of the valve shaft 17, and the locating pin 74a is inserted into the locating groove 21d located on the inner surface 21b of the first valve plate 21 (see FIG. 9).

[0091] Furthermore, as shown in Figures 9 and 14, the first clamping piece 31 is rotated around the axis of the first fastening bolt 67, inserting the first engaging protrusion 34 into the first engaging recess 36. When the first fastening bolt 67 is securely fastened to the valve shaft 17, the first engaging protrusion 34 engages in the first engaging groove 36a, and the first valve plate 21 is secured in close contact with the first side surface 17a of the valve shaft 17 via the first clamping piece 31.

[0092] Furthermore, as shown in Figures 11 and 14, when the third clamping piece 60, which is mounted on the upper end of one of the two support platforms 51 (e.g., the left side), rotates around the axis of the third fastening bolt 72, after the engagement state of the fifth engaging protrusion 65 relative to the second valve plate 22 is released, the fourth engaging protrusion 63 is inserted into the fourth engaging recess 66, and the third engaging protrusion 62 is inserted into the third engaging recess 64. Furthermore, when the third fastening bolt 72 is securely fastened to the valve shaft 17, the fourth engaging protrusion 63 engages with the fourth engaging groove 66a, and the third engaging protrusion 62 engages with the third engaging groove 64a. In the state where the first valve plate 21 and the second valve plate 22 are separated by the support platform 51 on one side in the left-right direction, the first valve plate 21 and the second valve plate 22 are fastened to each other by the third clamping piece 60.

[0093] Furthermore, the other of the two support platforms 51 undergoes the same operation as the aforementioned support platform 51. With the support platform 51 separating the first valve plate 21 and the second valve plate 22 on the other side in the left-right direction, the first valve plate 21 and the second valve plate 22 are secured together by the third clamping piece 60. As a result, as shown in FIG13, the first valve plate 21 can be mounted on the valve shaft 17 with the first valve plate 21 and the second valve plate 22 secured together.

[0094] Next, the process of removing the second valve plate 22 will be explained. As shown in Figure 11, firstly, the third fastening bolts 72 of the respective third clamping plates 60 mounted on the two support platforms 51 are rotated in the loosening direction. As the third fastening bolts 72 rotate, the third clamping plates 60 move upward, causing the third engaging protrusion 62 and the fourth engaging protrusion 63 to disengage from the third engaging groove 64a and the fourth engaging groove 66a, respectively. Furthermore, as shown in Figure 15, the two third clamping plates 60, respectively arranged on the left and right sides in the rotational plane display around the shaft, disengage the third engaging protrusion 62 from the third engaging recess 64, and disengage the fourth engaging protrusion 63 from the fourth engaging recess 66, and engage the fifth engaging protrusion 65 into the third engaging recess 64.

[0095] Furthermore, the second fastening bolt 71 of the second clamping piece 40, which is mounted on the valve shaft 17 shown in FIG. 10, is rotated in a loosening direction. With the rotation of the second fastening bolt 71, the second clamping piece 40 moves upward, disengaging the second engaging protrusion 43 from the second engaging groove 45a of the second engaging recess 45. Also, as shown in FIG. 15, the second clamping piece 40 is rotated clockwise in a plan view, disengaging the second engaging protrusion 43 from the second engaging recess 45. As a result, when the second valve plate 22 is lifted upward relative to the valve shaft 17, the second valve plate 22 can be removed from the valve shaft 17 and the support platform 51.

[0096] Next, the case where the second valve plate 22 is mounted on the valve shaft 17 will be described. First, as shown in FIG15, the inner surface 22b of the second valve plate 22 is positioned opposite the first valve plate 21 with the valve plate 17 facing towards it. The second protrusion 20 of the valve shaft 17 is inserted into the lower engagement recess 27 of the second valve plate 22 (see FIG10), and the fourth protrusion 54, located at the lower part of each of the two support platforms 51, is inserted into the lower engagement recess 29 of the second valve plate 22 (see FIG11). The inner surface 22b of the second valve plate 22 is brought into contact with the second side surface 17b of the valve shaft 17, and the locating pin 74b is inserted into the locating groove 22d located on the inner surface 22b of the second valve plate 22 (see FIG9).

[0097] Furthermore, as shown in Figures 10 and 15, the second clamping piece 40 is rotated around the shaft of the second fastening bolt 71, inserting the second engaging protrusion 43 into the second engaging recess 45. When the second fastening bolt 71 is rotated in the fastening direction, the second clamping piece 40 moves downward, inserting the second engaging protrusion 43 into the second engaging groove 45a. Furthermore, when the first fastening bolt 67 is further rotated in the fastening direction, and the first fastening bolt 67 is securely fastened and fixed relative to the valve shaft 17, the second valve plate 22 is fastened through the second clamping piece 40 in a state of close contact with the second side surface 17b of the valve shaft 17.

[0098] Furthermore, as shown in Figures 11 and 15, when the third clamping piece 60, which is mounted on the upper end of one of the two support platforms 51 along its longitudinal direction, is rotated, the engagement of the fifth engaging protrusion 65 with respect to the first valve plate 21 is released. Then, the third engaging protrusion 62 is inserted into the third engaging recess 64, and the fourth engaging protrusion 63 is inserted into the fourth engaging recess 66. When the third fastening bolt 72 is rotated in the tightening direction, the third clamping piece 60 moves downward, engaging the third engaging protrusion 62 into the third engaging groove 64a, and engaging the fourth engaging protrusion 63 into the fourth engaging groove 66a. When the third fastening bolt 72 is securely tightened relative to the third clamping piece 60, the longitudinal sides of the first valve plate 21 and the second valve plate 22 are fastened together with respect to the support platform 51.

[0099] Furthermore, similarly to the aforementioned support platform 51, the other support platform 51 on the other side of the longitudinal direction of the two support platforms 51 is operated so that the other sides of the longitudinal direction of the first valve plate 21 and the second valve plate 22 are connected to each other with the support platforms 51 in between. As a result, as shown in FIG13, the second valve plate 22 can be mounted on the valve shaft 17.

[0100] As described above, according to the gate valve 10 of the second embodiment, by simply loosening the tightening of the first to third fastening bolts 67, 71, and 72 and rotating the first clamping plate 31, the second clamping plate 40, and the third clamping plate 60, the first valve plate 21 or the second valve plate 22 can be detachably installed on the valve shaft 17.

[0101] [Third Implementation Form] Next, a third embodiment of the gate valve 10 related to the present invention will be described. In the third embodiment, the differences from the first and second embodiments described above will be mainly explained, and the same symbols will be assigned to embodiments that are the same as those in the first and second embodiments, and their descriptions will be omitted.

[0102] While the gate valve 10 of the above embodiment is composed of a valve shaft 17, a first valve plate 21 and a second valve plate 22, and an operating mechanism 24, the gate valve of this embodiment is further composed of a valve box 11 that houses the first valve plate 21 and the second valve plate 22. Furthermore, this embodiment is illustrated in FIG16, and is described in the case where the gate valve 10 is arranged between the adjacent first chamber 1 and second chamber 4.

[0103] First, a brief description of the first chamber 1 and the second chamber 4 will be provided. The first chamber 1 is a material chamber that houses a conveying device for moving workpieces such as semiconductor substrates into and out of the second chamber 4. The second chamber 4 is a processing chamber in which workpiece processing is carried out under a vacuum atmosphere.

[0104] The first chamber 1 and the second chamber 4 are respectively provided with a first chamber port 2a and a second chamber port 5a for workpieces to pass through during loading and unloading. The first chamber port 2a communicates with the first gate (first opening) 12a of the valve box 11 of the gate valve 10, and the second chamber port 5a communicates with the second gate (second opening) 13a of the gate valve 10. The chambers 2a and 5a are interconnected by the first valve plate 21 and the second valve plate 22 of the gate valve 10, or can be opened and closed individually. The first chamber 1 and the second chamber 4 are airtight.

[0105] The first chamber 1 and the second chamber 4 are hollow box-shaped structures, each having a first chamber wall 2 and a second chamber wall 5 extending along the front (side wall) 12 and rear (side wall) 13 on both sides of the valve box 11 in the front-rear direction, respectively. The first chamber wall 2 has a first opening 2a penetrating the transport space 1a of the first chamber 1, and the second chamber wall 5 has a second opening 5a penetrating the processing space 4a of the second chamber 4. The first opening 2a and the second opening 5a are generally rectangular with similar shapes, extending in the left-right direction (longitudinal direction) orthogonal to the front-rear direction. Furthermore, the first opening 2a and the second opening 5a may also be of the same shape.

[0106] The gate valve 10, as shown in Figures 16 and 17, includes: a hollow valve box 11 with a valve space 11a formed inside the first gate 12a and the second gate 13a; a first valve plate 21 and a second valve plate 22 that communicate between the pair of first gates 12a and second gates 13a by the operation of the valve shaft 17 (that is, communicate or airtightly block the gates 12a and 13a through the valve space 11a); a valve shaft 17 connected to the valve plates 21 and 22; and an operating mechanism 24 that performs the opening and closing operation of the first valve plate 21 and the second valve plate 22 through the valve shaft 17.

[0107] In this embodiment, an operating mechanism 24 is provided at the bottom of the valve box 11, so that the valve shaft 17 protrudes from the bottom of the valve box 11 into the valve space 11a. The front wall 12 and the rear wall 13 of the valve box are provided with a first gate 12a and a second gate 13a, which are opposite to each other.

[0108] The first valve plate 21 pushes the sealing member 21a of the first valve plate 21 to the valve sealing surface 13b around the second gate 13a of the rear wall 13 to seal the second gate 13a. The second valve plate 22 pushes the sealing member 22a of the second valve plate 22 to the valve sealing surface 12b around the first gate 12a of the front wall 12 to seal the first gate 12a.

[0109] The two cylinders 25 constituting the operating mechanism 24 operate the opening and closing of the first valve plate 21 and the second valve plate 22 via the valve shaft 17. Specifically, the cylinders 25 are configured to move and switch between the following positions: a first closed position in which the sealing member 22a of the second valve plate 22 is pushed toward the valve sealing surface 12b around the first gate 12a to close the first gate 12a; a second closed position in which the sealing member 21a of the first valve plate 21 is pushed toward the valve sealing surface 13b around the second gate 13a to close the second gate 13a; and a retracted position in which the first valve plate 21 and the second valve plate 22, and the first and second gates 12a and 13a are connected to each other.

[0110] Furthermore, the retraction position may include the position where the first valve plate 21 and the second valve plate 22 are located in the middle of the first and second gates 12a and 13a and are connected to the first and second gates 12a and 13a, and the lower position below the middle position. It may also be the lower position in the case where the first valve plate 21 moves toward the first closed position, or the second valve plate 22 moves toward the second closed position, so that the first valve plate 21 moves from the first closed position to the lower position, or the second valve plate 22 moves directly from the second closed position to the lower position.

[0111] The valve box 11 has: a front wall 12 and a rear wall 13 spaced apart and arranged opposite each other in the front-rear direction; a pair of side walls 14 connecting the two ends of the front wall 12 and the rear wall 13 in the left-right direction; and a top wall 15 covering the upper opening 15a of the walls. The first gate 12a and the second gate 13a provided on the front wall 12 and the rear wall 13 are rectangular and extend in the left-right direction. The first gate 12a communicates with the first cavity opening 2a of the first chamber 1 in a similar shape. Furthermore, the first gate 12a and the second gate 13a may also be of the same shape.

[0112] The top wall 15 is detachably mounted on the upper ends of the front wall 12, the rear wall 13, and a pair of side walls 14, 14. In this embodiment, the top wall 15 is detachably mounted on the walls by means of fastening members such as bolts 16.

[0113] In this embodiment of the gate valve 10, when the first valve plate 21 or the second valve plate 22 is removed from the valve shaft 17, as shown in FIG16, the first valve plate 21 or the second valve plate 22 is exposed from the valve box 11 through the upper opening 15a of the opening in the top wall 15. Furthermore, when removing the first valve plate 21 from the valve shaft 17, after moving the second valve plate 22 towards the second closed position, the same removal operation as in the first and second embodiments described above is performed to remove the first valve plate 21 from the valve shaft 17. Similarly, when removing the second valve plate 22 from the valve shaft 17, after moving the first valve plate 21 towards the first closed position, the same removal operation as in the first and second embodiments described above is performed to remove the second valve plate 22 from the valve shaft 17.

[0114] On the other hand, when the first valve plate 21, after being removed, is installed on the valve shaft 17, so that the second valve plate 22 is moved toward the second closed position, the first valve plate 21, installed through the upper opening 15a of the valve box 11 with the opening in the top wall 15 removed, is inserted into the valve space 11a of the valve box 11. Furthermore, the same installation operation as in the first and second embodiments described above is performed to install the first valve plate 21 onto the valve shaft 17. Similarly, when the second valve plate 22, after being removed, is installed on the valve shaft 17, so that the first valve plate 21 is moved toward the first closed position, the second valve plate 22, installed through the upper opening 15a of the valve box 11 with the opening in the top wall 15 removed, is inserted into the valve space 11a of the valve box 11. Furthermore, the same installation operation as in the first and second embodiments described above is performed to install the second valve plate 22 onto the valve shaft 17.

[0115] As described above, in this embodiment, the gate valve 10 can be easily removed from the valve box 11 by removing the top wall 15, and the first valve plate 21 or the second valve plate 22 can be easily removed and installed through the upper opening 15a. Furthermore, the first to third fastening bolts 67, 71, and 72, which are inserted into the first to third clamping pieces 31, 40, and 60, are designed to prevent them from falling off. Therefore, during the replacement of the first valve plate 21 or the second valve plate 22, these fastening bolts 67, 71, and 72 are prevented from falling into the valve box 11. This improves the ease of maintenance of the valve plates 21 and 22.

[0116] Furthermore, in the above-described embodiment, the first clamping piece 31, the second clamping piece 40, and the third clamping piece 60 of the fastening mechanism 30 and the support mechanism 50 are respectively formed with convex engagement protrusions 34, 43, 62, and 63. Although this indicates the case where the engagement recesses 36, 45, 64, and 66 that engage with these parts are concave, it is not limited to this. The first clamping piece 31, the second clamping piece 40, and the third clamping piece 60 may also each have concave engagement recesses (not shown), and the convex engagement protrusions (not shown) that engage with these parts are provided on the first and second valve plates 21 and 22. Furthermore, although the above-described embodiment describes the provision of a set of support mechanisms 50 spaced between the valve plates 21 and 22 at both ends of the first valve plate 21 and the second valve plate 22 arranged opposite to each other, it is not limited to this. It is also possible to further provide one or more other support mechanisms 50 between the valve plates 21 and 22 on the inner side of the set of support mechanisms 50 in the longitudinal direction.

[0117] 10: Gate valve 11: Valve box 11a: Valve space 12: Anterior wall (lateral wall) 12a: Gate 1 (First Opening) 13: Posterior wall (lateral wall) 13a: Second gate (second opening) 14: Sidewall 15: Top Wall 17: Valve shaft 17a: First side profile 17b: Second side profile 17c: Shaft end face 19: First protruding part (locking part, protrusion) 20: Second protruding part (locking part, protrusion) 21: Valve Plate 1 21b,22b: inner surface 21e, 22e: Sealing surface (outer side) 22: Second valve plate 24: Operating mechanism 26, 27: Lower side engaging recessed portion (engaging portion, recessed portion) 28, 29: Lower side engagement recess (base end side engagement recess) 30: Fastening mechanism 31: First clamping piece 32: First clamping main body 33: Main body locking claw (first locking claw) 34: First engaging protrusion 36: 1st engaging recess 36c: First extended recess 40: Second clamping piece 41: Second clamping main body 42: Main body locking claw (second locking claw) 43: Second engaging protrusion 45: 2nd engagement recess 45c: Second extended recess 47: Gap 50: Supporting institutions 51: Support platform 51c: Support end face 53: Third protrusion (base end side engaging protrusion, protrusion) 54: Fourth protrusion (base end side engaging protrusion, protrusion) 60: Third clamping piece 61: Third clamping main body 61b: Highlight the part 62: Third engaging protrusion 63: Fourth engaging protrusion 64: 3rd engagement recess 64d: Third extended recess 65: Fifth engaging protrusion 66: 4th engagement recess 67: First fastening bolt (first fastening component) 68a: External thread section 68b: Small diameter section (unthreaded section) 70: Internal thread section (threaded hole) 71: Second fastening bolt (second fastening component) 72: Third fastening bolt (third fastening component) L: Axis P1: Engagement Position P2: naked position

Claims

1. A gate valve disposed between two adjacent first and second chambers for communicating with or separately opening and closing a first opening in the first chamber and a second opening in the second chamber, characterized in that: the gate valve comprises: a valve shaft extending axially from a base end to a front end; a first valve plate and a second valve plate mounted on the front end of the valve shaft along the axial direction, elongatedly formed in a direction orthogonal to the shaft, and having: an inner surface facing the valve shaft and an outer surface with an annular sealing member facing away from the inner surface; and an operating mechanism that, by actuating the valve shaft, moves the first and second valve plates to a retracted position where the first opening and the second opening communicate with each other; a first closed position where the outer surface of the first valve plate closes the first opening; and a second closed position where the outer surface of the second valve plate closes the second opening, and the gate valve further comprises: The fastening mechanism abuts the inner surfaces of the first valve plate and the second valve plate against the front end of the valve shaft, holding the front end of the valve shaft between the valve plates, thereby detachably fastening the first and second valve plates to the valve shaft, so that the first and second valve plates can be detachably mounted on the front end of the valve shaft, and at least one set of support mechanisms detachably fastens the valve plates to each other at at least two ends along the longitudinal direction of the first and second valve plates.

2. The gate valve as described in claim 1, wherein, The aforementioned fastening mechanism comprises: a first clamping piece disposed at the front end of the valve shaft along the axial direction, spanning between the valve shaft and the first valve plate, detachably engaging with the first valve plate and detachably fixed with respect to the valve shaft; a second clamping piece disposed at the front end of the valve shaft along the axial direction, spanning between the valve shaft and the second valve plate, detachably engaging with the second valve plate and detachably fixed with respect to the valve shaft; and a first fastening member and a second fastening member, which detachably fix the first clamping piece and the second clamping piece to the front end of the valve shaft, respectively, wherein the base end ends of the first and second valve plates along the axial direction are engaged with the front end of the valve shaft from the front end side. With the first and second clamping pieces fixed to the valve shaft by the first and second fastening members, the front ends of the first and second valve plates are pushed toward the inner surfaces by the engagement of the first and second clamping pieces with the first and second valve plates, and the base ends of the valve plates are pushed toward the inner surfaces by the interlocking of the base ends of the valve plates with the front ends of the valve shaft, thereby fastening the first and second valve plates to the front ends of the valve shaft.

3. The gate valve as described in claim 2, wherein, The engagement between the base end of the pair of valve plates and the front end of the valve shaft is formed by the engagement of engagement portions respectively provided at the base end of the pair of valve plates and a pair of engaged portions provided at the front end of the valve shaft. The engagement portion is one of a recess and a protrusion that engages with it, and the engaged portion is the other of the recess and the protrusion. The first valve plate and the second valve plate have a first engagement recess and a second engagement recess that open towards the front end of the axial direction at the center of their longitudinal direction on their inner surfaces. The first clamping piece and the second clamping piece have a first engagement protrusion and a second engagement protrusion that engage with the first and second engagement recesses. With the first engaging protrusion engaged with the first engaging recess, and the engaging portion formed on the first valve plate and the valve shaft engaged with the engaged portion, the first fastening member fixes the first clamping piece to the valve shaft. This causes the first engaging protrusion to exert a pushing force in the inward direction of the first valve plate relative to the first engaging recess, and the engaging portion to exert a pushing force in the inward direction of the first valve plate relative to the engaged portion, thereby fastening the first valve plate to the valve shaft. The second engaging protrusion engages with the second engaging recess, and in the state where the engaging portion formed on the second valve plate and the valve shaft is engaged with the engaged portion, the second fastening member fixes the second clamping piece to the valve shaft, thereby causing the second engaging protrusion to exert a pushing force in the inner surface direction of the second valve plate relative to the second engaging recess, and causing the engaging portion to exert a pushing force in the inner surface direction of the second valve plate relative to the engaged portion, thereby fastening the second valve plate to the valve shaft.

4. The gate valve as described in claim 3, wherein, The first and second fastening components are a first fastening bolt and a second fastening bolt. A threaded hole for threading the fastening bolt is provided on the front end face of the valve shaft in the axial direction. Through holes for inserting the first and second fastening bolts are provided on the first and second clamping pieces. The first fastening bolt is inserted through the through hole of the first clamping piece and screwed into the threaded hole of the valve shaft, thereby fixing the first clamping piece to the valve shaft. The second fastening bolt is inserted through the through hole of the second clamping piece and screwed into the threaded hole of the valve shaft, thereby fixing the second clamping piece to the valve shaft.

5. The gate valve as described in claim 4, wherein, The first clamping piece has a first engaging protrusion at one end separated from its through hole and a first locking pawl at the other end. When the first clamping piece is fixed with the first fastening bolt, the first locking pawl is locked to the valve shaft with respect to the first engaging protrusion. The second clamping piece has a second engaging protrusion at one end separated from its through hole and a second locking pawl at the other end. When the second clamping piece is fixed with the second fastening bolt, the second locking pawl is locked to the valve shaft with respect to the second engaging protrusion.

6. The gate valve as described in claim 4, wherein, The first clamping piece, in the state of loosening the first fastening bolt, between the engaged position where the first engaging protrusion engages with the first engaging recess and the disengaged position where the first engaging protrusion is disengaged from the first engaging recess, can freely rotate around the axis of the first fastening bolt. When the first clamping piece is rotated from the engaged position to the disengaged position, it is housed within the gap between the inner surface of the first valve plate and the inner surface of the second valve plate. The second clamping piece, in the state of loosening the second fastening bolt, between the engaged position where the second engaging protrusion engages with the second engaging recess and the disengaged position where the second engaging protrusion is disengaged from the second engaging recess, can freely rotate around the axis of the second fastening bolt. When the second clamping piece is rotated from the engaging position to the disengaged position, it is housed in the gap between the inner surface of the first valve plate and the inner surface of the second valve plate.

7. The gate valve as described in claim 6, wherein, The first and second fastening bolts described above have: an axially extending shaft portion; a head provided at the axially front end of the shaft portion; and an external thread portion formed on the outer periphery of the shaft portion. An internal thread portion that can engage with the external thread portion is formed on the inner surface of the through hole provided in the first and second clamping pieces. The shaft portion further has a fine diameter portion whose outer diameter is smaller than the inner diameter of the internal thread portion in the part on the head side than the external thread portion. The fine diameter portion is inserted into the through hole. When the first and second fastening bolts are loosened, the head side end of the external thread portion abuts against the internal thread portion of the first and second clamping pieces.

8. The gate valve as described in claim 1, wherein, The aforementioned support mechanism comprises: at least a pair of support platforms clamped between the first and second valve plates at at least two ends along their longitudinal direction; a third clamping piece disposed across the first and second valve plates from the respective axial front ends of the pair of support platforms, detachably engaging with the first and second valve plates, and detachably fixed relative to each support platform; and a third fastening member detachably fixing the third clamping piece to the axial front end of the support platform, wherein the axial base end ends of the first and second valve plates engage with the support platforms from their front ends. With the third clamping piece engaged with the first and second valve plates, and the base end of the pair of valve plates engaging with the support platform, the third clamping piece is fixed to the support platform by the third fastening member, thereby pushing the front end and base end of the first and second valve plates toward the inner surfaces respectively, so as to fasten the first and second valve plates and the support platform together.

9. The gate valve as described in claim 8, wherein, The engagement between the base end faces of the aforementioned pair of valve plates and the aforementioned support platform is formed by the engagement of base end side engagement recesses provided on the base end faces of the aforementioned pair of valve plates and a pair of base end side engagement protrusions provided on the aforementioned support platform. The first valve plate and the second valve plate are provided with a third engagement recess and a fourth engagement recess, both opening at least at both ends toward the axial front end on their inner surfaces in the longitudinal direction. The third clamping piece is provided with a third engagement protrusion and a fourth engagement protrusion that engage with the third engagement recess and the fourth engagement recess. The third and fourth engaging protrusions are engaged with the third and fourth engaging recesses, respectively. With the base-end side engaging recesses and base-end side engaging protrusions formed on the first and second valve plates and the support platform engaged, the third fastening member fixes the third clamping piece to the support platform. This causes the third engaging protrusion to exert a pushing force in the inward direction of the first valve plate relative to the third engaging recess and the fourth engaging protrusion to exert a pushing force in the inward direction of the first valve plate relative to the base-end side engaging protrusion, thereby fastening the first and second valve plates and the support platform together.

10. The gate valve as described in claim 9, wherein, The third fastening component is a third fastening bolt. A threaded hole for threading the third fastening bolt is provided on the front end face of the support platform in the axial direction. A through hole for inserting the third fastening bolt is provided on the third clamping piece. The third fastening bolt is inserted through the through hole of the third clamping piece and threaded into the threaded hole of the support platform, thereby fixing the third clamping piece to the support platform.

11. The gate valve as described in claim 10, wherein, The aforementioned third engaging recess, fourth engaging recess, and base-end side engaging recess extend toward the longitudinal direction of the valve plate, with their outer ends opening toward the outer side of their longitudinal direction. The aforementioned support mechanism engages the aforementioned third engaging protrusion and fourth engaging protrusion of the aforementioned third clamping piece with the aforementioned third engaging recess and fourth engaging recess of the aforementioned first and second valve plates, and with the aforementioned base-end side engaging recess engaged with the aforementioned base-end side engaging protrusion. By loosening the aforementioned third fastening bolt, the aforementioned third engaging protrusion and fourth engaging protrusion slide along the aforementioned third engaging recess and fourth engaging recess, and the aforementioned base-end side engaging recess slides along the aforementioned base-end side engaging protrusion, allowing it to be removed from the aforementioned first and second valve plates.

12. The gate valve as described in claim 10, wherein, The third clamping piece loosens the third fastening bolt, thereby engaging the third engaging protrusion with the third engaging recess, and allowing the third clamping piece to freely rotate around the axis of the third fastening bolt from the state where the fourth engaging protrusion is engaged with the fourth engaging recess. The third clamping piece further has a protruding portion that projects radially outward from the third fastening bolt. On the protruding portion, a fifth engaging protrusion is formed at its forward end, engaging the third and fourth engaging recesses. The third and fourth engaging protrusions are positioned on opposite radial sides of the third fastening bolt, and the fifth engaging protrusion is positioned perpendicular to the axis of the third fastening bolt relative to the third and fourth engaging protrusions. The third clamping piece is configured such that, with the third and fourth engaging protrusions engaged with the third and fourth engaging recesses, the third fastening bolt is loosened, causing the third clamping piece to rotate around the axis of the third fastening bolt. This engages the fifth engaging protrusion with either the third or fourth engaging recess to lock either the first or second valve plate, and allows the other valve plate to be released from engagement with the third clamping piece.

13. The gate valve as described in claim 12, wherein, The aforementioned third fastening bolt has: an axially extending shaft portion; a head provided at the axially front end of the aforementioned shaft portion; and an external thread portion formed on the outer periphery of the aforementioned shaft portion. An internal thread portion that can engage with the aforementioned external thread portion is formed on the inner surface of the aforementioned through hole opened in the aforementioned third clamping piece. The aforementioned shaft portion further has a portion that is further on the head side than the aforementioned external thread portion, and a fine diameter portion whose outer diameter is smaller than the inner diameter of the aforementioned internal thread portion. The fine diameter portion is inserted into the aforementioned through hole. When the aforementioned third fastening bolt is loosened, it is configured such that the head side end of the aforementioned external thread portion abuts against the aforementioned third clamping piece.

14. The gate valve described in any of claims 1 to 13, wherein, The gate valve further comprises a valve box that houses the first valve plate and the second valve plate. The valve box has a side wall surrounding the first and second valve plates along the axis and a top wall that is detachably mounted to the front end of the side wall along the axial direction. The first opening and the second opening are provided on the side wall in a manner opposite to each other.

Images