JP2013200031A - Soft seal gate valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain an elution amount of a rubber additive, while securing corrosion resistance of a valve element of a soft seal gate valve.SOLUTION: A soft seal gate valve includes a metallic casting valve element 10 for opening-closing by linearly moving in the orthogonal direction to a fluid passage 1 in a valve casing 2, and rubber linings G1 and G2 for sealing between an inner surface of the valve casing and a surface of a core material 11 of the valve element, is applied to the surface of the core material of the valve element. The rubber lining is applied to a range capable of securing sealability with the inner surface of the valve casing 2, and rust preventive (corrosion resistant) processing is applied by a resin covering R to a part except for applying the rubber lining of the core material surface. The rubber lining is made to reach a recessed part adjacent to a core material body part 13, and the joining force is enhanced, and the surface simplifies a metal mold shape as a plane.

Description

  The present invention relates to a soft seal gate valve in which a rubber seal material is attached to a valve body that linearly moves in a direction orthogonal to a fluid passage in a valve box to open and close the fluid passage.

The gate valve opens and closes the fluid passage by linearly moving the valve body in a direction orthogonal to the fluid passage in the valve box, and a valve body valve seat that seals between the valve body outer peripheral surface and the valve box inner surface There is a so-called soft seal gate valve with a water seal performance that is improved by installing a rubber seal material.
The valve body of this soft seal gate valve ensures water-stopping performance by applying rubber lining as a rubber seal material that seals between the inner surface of the metal core material such as cast iron and cast steel. In addition, a material that can prevent corrosion due to contact with the fluid flowing in the fluid passage of the core material is often used (see Patent Document 1, paragraph 0024, FIG. 1).

  However, when a soft seal gate valve having a valve body with a rubber lining on the entire surface is used for waterworks, an anti-aging agent, a vulcanization accelerator, a vulcanization acceleration aid, etc. contained in the rubber of the rubber lining, etc. The rubber additive may be dissolved in tap water, and the resulting odor of tap water and its environmental impact may be problematic.

  On the other hand, in a gate valve that is not fitted with a rubber seal material (no rubber lining) on the valve body, there is no problem due to the dissolution of the rubber additive, but the entire valve body is made of stainless steel, There is a problem that it is necessary to give rust prevention treatment to the entire valve body to impart corrosion resistance to the valve body, and since a rubber seal material is not applied, sufficient water stop performance cannot be obtained.

Under such circumstances, rubber lining is applied to the entire surface of the valve body, and when the valve is closed, a portion of the rubber lining exposed to tap water is coated with a polyethylene film, and the rubber additive is applied from the rubber of the coated rubber lining. There is a technology that prevents dissolution into tap water (see Patent Document 2 Abstract, FIG. 1).
Further, the valve body is constituted by a cylindrical member having a hole portion that communicates with the upstream side and the downstream side, and a stainless steel member that closes the hole portion, and only a seal portion that serves as a valve body valve seat at the periphery of the cylindrical member. In addition, there is also a technology that suppresses the rubber additive from dissolving into the tap water from the rubber of the rubber lining, using the stainless steel member as the portion exposed to tap water. (See paragraphs 0022 FIGS. 1-2).

JP 2010-121675 A JP 2007-154970 A JP 2011-163440 A

In the technique described in Patent Document 2, a polyethylene film is coated on a portion of a rubber lining exposed to tap water when the valve is closed. However, it is not easy to partially cover the rubber lining with the film. As shown in FIG. 1, lines 1 to 3 of paragraph 2, the entire rubber lining is covered with a film. For this reason, the sealing is performed by the pressure contact of the film, and there is a problem in the sealing performance. Moreover, in addition to a rubber lining process, the thermocompression bonding process of a polyethylene film is required, and there exists a problem that the manufacturing process of a valve body becomes complicated and manufacturing cost becomes high.
The technique in which the part exposed to tap water described in Patent Document 3 is made of a stainless steel plate is said to eliminate the drawbacks of Patent Document 2 (paragraphs 0006 to 0008 of the same document), but it is necessary to manufacture a press-processed product separately. As it is, there is still a problem in manufacturing cost.

  It is an object of the present invention to suppress the amount of rubber additive that dissolves while ensuring the corrosion resistance (rust prevention) of the valve body of the soft seal gate valve.

In order to solve the above-mentioned problems, the present invention first makes the core material of the valve body made of a metal casting. Since the casting is a casting, the entire shape of the core material can be easily manufactured, and the cost becomes low.
Next, according to the present invention, in the core material made of cast metal, a rubber lining is applied to a range in which the sealing performance with the inner surface of the valve box can be secured (at least a portion forming the valve body valve seat), and the rubber lining is applied. The exposed core material portion was subjected to rust prevention treatment.
The “range in which sealing performance can be ensured” refers to the same extent as the range of rubber lining in Patent Document 3 (at least the valve body valve seat portion), and the narrowest possible range is as long as the effects of the present invention can be exhibited. Preferably, it is set appropriately by experiment or the like. If rubber lining is applied to the range that can guarantee this sealability (at least the valve body valve seat part), the sealability can be ensured, and the rubber lining is not applied to the parts other than the rubber lining. Can be suppressed. On the other hand, since the exposed portion of the core material that has not been subjected to rubber lining is subjected to rust prevention treatment, it has corrosion resistance (rust prevention).

As a specific configuration of the present invention, a valve body that linearly moves in a direction orthogonal to the fluid passage in the valve box to open and close the fluid passage is provided. In a soft seal gate valve with rubber lining that forms a valve body valve seat to be sealed, the valve body has a rubber lining on the surface of a core material made of cast metal, and the rubber lining is connected to the valve casing valve seat. The core material can be applied within a range that can ensure the sealing property, and the core material can have a structure in which the background is exposed and the exposed portion is subjected to rust prevention other than the rubber lining.
As in this configuration, the corrosion resistance of the metal casting valve body is ensured by applying rust prevention treatment to at least the entire area where the rubber lining is not applied, on the surface of the core material of the valve body. Rubber lining was applied to the entire surface of the core of the valve body by limiting the area where rubber lining is applied to the area (valve valve seat (seal part)) that contacts the inner surface of the valve box when the valve is closed. Compared to that, the area of the rubber lining exposed to the fluid flowing through the fluid passage is reduced, and the amount of the rubber additive dissolved out can be suppressed.

  In the soft seal gate valve of this configuration, for example, the valve shaft in the orthogonal direction is inserted into the valve box, and the valve box is formed with a valve body housing portion that opens upward at the center in the flow direction of the fluid passage, A lid through which the valve rod is inserted is attached to the opening edge of the valve body housing portion, and the guide in the orthogonal direction is fitted to one of the outer peripheral surface of the valve body and the inner peripheral surface of the valve box, and the guide is fitted to the other. Each of the grooves in the same orthogonal direction is formed, and the valve stem is threaded through the female thread piece of the valve disc. A configuration in which the fluid passage is opened and closed by linearly moving in the orthogonal direction can be employed.

In this configuration, the core member has a mounting portion in a state in which the internal thread piece is prevented from coming off at an upper portion of the cylindrical body portion, and a valve rod passing through the internal thread piece enters the central space of the body portion, and the body portion Guides or grooves on both sides of the body, the required range around the central axis in the flow direction of the fluid passage on the body surface between the guides or grooves on both sides is the exposed part of the core material ground (casting surface), and the exposed part It is possible to have a rubber lining around.
The “required range around the central axis” in this configuration is desirably as wide as possible as long as there is no hindrance to the formation of the valve body valve seat by the rubber lining, and is set appropriately by experiment or the like in consideration of this point.
At this time, the exposed surface of the core material other than the rubber lining which forms the valve body valve seat, for example, the surface and the inner surface of the female screw piece mounting portion, the guide surface, the groove inner surface, the inner surface of the trunk portion, and the trunk surface It is preferable to perform at least a rust prevention treatment on the exposed portion of the core material background around the central axis. This is because these parts are likely to rust due to fluid touching or wear.

Further, in the soft seal gate valve having a core material having the cylindrical body portion, a pair of opposed protrusions in the orthogonal direction are formed on both side surfaces of the body portion, and the groove is formed between the protrusions. Then, in many cases, a concave portion is formed between the protrusion and the trunk portion, and in this case, the rubber lining around the exposed portion of the trunk surface is brought into the concave portion, and the rubber lining surface in the concave portion is It can be set as the structure used as the plane which follows an orthogonal direction.
When the rubber lining is thus brought into the concave portion, the holding force of the rubber lining of the seal portion can be sufficiently secured by the rubber lining of the concave portion without rubber lining the entire body surface. Further, since the rubber lining surface of the concave portion is a plane along the orthogonal direction, the mold shape (cavity shape) of the portion becomes simple, and the die manufacturing cost can be reduced.
Further, when the recess is formed in this way, the volume of the core material made of a metal casting having a large specific gravity is reduced to reduce the weight. On the other hand, the core between the ridge and the trunk is formed so that the recess does not occur. The thickness of the material may be a flat surface similar to the rubber lining surface of the recess. In this case, the flat surface portion does not necessarily need to be rubber-lined and can be subjected to rust prevention treatment.

  Although various means can be considered for the rust prevention treatment, if the core metal is stainless steel, it will not rust even if exposed, but it is usually performed by resin coating. The resin coating is performed by applying a resin rust preventive agent. The application may be performed by brush coating, spray coating, powder coating, or the like. In the powder coating, a portion of the core material to be subjected to rubber lining is masked to form a resin coating layer (rust preventive layer), and then the rubber lining can be performed by injection molding using a mold.

  As described above, the present invention applies rust prevention treatment to the entire surface of the core member of the valve body where the rubber lining forming the valve body valve seat is not applied, and the rubber lining is applied to the surface. Since the area to be applied is limited to the seal part, the amount of the rubber additive leached out is higher than that obtained by applying rubber lining to the entire surface of the core of the valve body while ensuring the sealing performance and the corrosion resistance of the valve body. Can be reduced. Therefore, there is no possibility of causing red water or odor problems even when used for waterworks, and it can be effectively used as an environmental measure. In addition, the manufacturing cost can be reduced.

Partially cutaway perspective view of an embodiment of a soft seal gate valve according to the present invention Vertical sectional view of the same embodiment The perspective view of the valve body of the embodiment It is manufacture explanatory drawing of the valve body, (a) is a front view at the time of completion of manufacture, (b) is a front view before rubber lining. Sectional view taken along the line II of FIG. (A)-(c) is a longitudinal cross-sectional view which shows the manufacturing procedure of the valve body Vertical sectional view of soft seal gate valve of other embodiment Cutting plan view of the valve body portion of the same embodiment Front view of the valve body Right side view of the valve body II-II sectional view of FIG. (A)-(c) is a longitudinal cross-sectional view which shows the manufacturing procedure of the valve body

  One embodiment of the soft seal gate valve according to the present invention is shown in FIG. 1 to FIG. 6, and this soft seal gate valve V is provided in the middle of the water pipe of the water supply, as shown in FIG. 1 and FIG. 2. A valve box 2 having a fluid passage 1 formed therein, a valve stem 3 inserted in a direction perpendicular to the fluid passage 1 (perpendicular to the fluid passage 1), and attached to the valve stem 3. A valve body 10 is provided. In the valve box 2, a valve body housing portion 2a that opens upward is formed at the center of the direction in which the fluid passage 1 extends (left and right direction in FIG. 2). At the opening edge of the valve body housing portion 2a, A lid 4 through which the valve stem 3 is inserted is attached.

  A copper alloy nut member (female thread piece) 5 is screwed to the threaded portion 3a of the valve stem 3 at the top of the valve body 10, and the valve body integral with the nut member 5 is obtained by rotating the valve stem 3. 10 is guided by the above-mentioned orthogonally long guide (protrusion) 7 provided on the inner surface of the valve box 2, and moves linearly in the vertical direction (perpendicular to the fluid passage 1) in the valve element housing portion 2a. Open and close passage 1.

  As shown in FIGS. 1 to 5, the valve body 10 mainly comprises a cast iron core material 11 formed by casting, and a nut mounting portion 12 is provided on the cylindrical body portion 13 of the core material 11. The nut member 5 fitted into the nut mounting portion 12 from the front side is prevented from coming off in the axial direction by a rectangular protruding portion 5a protruding from the outer peripheral surface thereof. Moreover, the said trunk | drum 13 comprises the center part of the core material 11, and the valve rod 3 which passed through the nut member 5 has entered the cylindrical space 13a in the trunk | drum 13 (refer FIG. 5). Guide grooves 14 into which the guide 7 of the valve box 2 is inserted (fitted and slid) are provided on both left and right sides of the body portion 13. The guide groove 14 is formed between the pair of opposed protrusions 14a, 14a in the orthogonal direction.

  Furthermore, the ground surface (cast surface) of the core material 11 is exposed around the central axis in the flow direction of the fluid passage 1 on the surface of the body portion 13 between the protrusions 14a, 14a on both sides of the core material 11, and the exposed portion of the cylinder is exposed. On the front and rear surfaces of the cylindrical body 13, an arcuate protrusion 15 a is provided on the upper side, and a drum-like protrusion 15 b is provided on the lower side. A rubber lining G is applied to the arcuate protrusion 15a and the drum-like protrusion 15b that surround the exposed portion. The core material which is not provided with the rubber lining G such as the exposed portion and the surface and inner surface of the mounting portion 12 surrounded by the rubber lining G, the surface of the protrusion 14a, the inner surface of the groove 14, the surface of the other trunk portion 13 and the inner surface. A resin coating R is applied to the entire exposed surface portion of 11 and an antirust treatment is performed. As a material for the rubber lining G, for example, ethylene / propylene rubber (EPDM) is used, and for the resin coating R, for example, an epoxy resin is used.

  The rubber lining G is provided within a range in which the sealing property with the inner surface of the valve box 2 can be secured, and forms a valve body valve seat. In this embodiment, the valve body of the cylindrical portion of the valve box 2 is the same as the conventional one. An arcuate protrusion G1 that contacts and slides on the valve box valve seat of the opening edge arcuate portion of the housing portion 2a, and a valve box valve seat on the lower inner peripheral surface of the valve body housing portion 2a of the valve box 2 ( And a drum-like protrusion G2 protruding in a central drum-like manner. For this reason, when the valve is closed (the state shown in FIG. 2), the lower outer periphery including the arc-shaped protrusion G1 and the drum-shaped protrusion G2 is the inner peripheral surface of the valve body housing portion 2a of the valve box 2 (valve box). The valve seat surface) is pressed against the inner peripheral surface of the valve box 2 to securely close the valve.

  Further, conventionally, the rubber lining G is also applied to the cylindrical surfaces before and after the core body portion 13 (leading line portion indicated by reference numeral 13b in FIG. 4A) (Patent Document 2, paragraph 0022, FIG. 6 (d))), in this embodiment, the rubber lining G is not applied to the cylindrical surfaces (the exposed portions) 13b before and after the core material barrel 13.

  Further, since the protrusion 14a is formed on the side surface of the cylindrical body portion 13, the boundary portion between the protrusion 14a and the cylindrical body portion 13 (the cylindrical surface 13b of the body portion 13 and the rubber lining G around the surface (arc-shaped) A recess 16 is formed between the rubber lining G1 of the protrusion 15a and the rubber lining G2 of the drum-like protrusion 15b), and the rubber lining G is brought into the recess 16, and the recess 16 The surface of the rubber lining G is a flat surface 16a along the orthogonal direction (see FIG. 5). As described above, when the rubber lining G is brought into the recess 16, the rubber lining G3 in the recess 16 can sufficiently hold the rubber lining G1 and G2 in the seal portion without the entire surface of the body 13 being rubber-lined. Can be secured. Further, since the rubber lining surface of the concave portion 16 is a flat surface 16a along the orthogonal direction, the mold shape (cavity shape) of the portion can be simplified, and the mold manufacturing cost can be reduced.

  As shown in FIGS. 6A to 6C, the valve body 10 is manufactured by first forming a core material 11 made of cast iron by casting (FIG. 6A), and then the core material. After masking the part to be subjected to 11 rubber lining G (G1, G2, G3) with a tape or the like, a resin coating R is applied by powder coating with a resin rust inhibitor (epoxy resin) (FIG. (B)), The resin-coated core material 11 is masked and loaded into a mold, and EPDM is injected into the mold cavity to inject rubber lining G (G1, G2, G3) (FIG. (C) )).

  The soft seal gate valve V has the above-described configuration, and the surface of the core member 11 of the valve body 10 is provided with a resin coating R which is a rust preventive treatment at least in the region where the rubber lining is not applied. Of these, the region where the rubber lining G is applied is limited to the seal portion, so that the sealing surface and the corrosion resistance of the valve body 10 are ensured, while the rubber lining is applied to the entire surface of the valve body core 11. It is possible to reduce the amount of rubber additive dissolved out. For this reason, even when used for waterworks, there is no possibility of causing red water or odor problems, and it can be used effectively as an environmental measure. In addition, the manufacturing cost can be reduced.

  In addition, since the surface of the valve body 10 that is in sliding contact with the guide 7 of the valve box 2, that is, the inner surface of the guide groove 14 (projection 14a), is coated with resin R, the guide groove 14 is also provided with rubber lining. Compared with the case where it is carried out, there also exists an advantage that the valve body 10 can be linearly moved smoothly and the force which rotates the valve stem 3 can be lessened.

  7 to 12 show a soft seal gate valve V ′ according to another embodiment. The soft seal gate valve V ′ is different from the soft seal gate valve V according to the above embodiment in the size of the valve body core 11. (Height etc.) are different and are substantially the same except that the entire surface of the core material 11 is coated with a resin coating R. The same reference numerals as above indicate the same thing.

As shown in FIG. 12, the means for applying the resin coating R to the entire surface of the core material 11 first forms a cast iron core material 11 by casting (FIG. 12 (a)), and then the core material. 11 is coated with a resin coating R (FIG. (B)), and a rubber lining G is applied to the lower outer peripheral portion including the arc-shaped projecting portion 15a and the drum-shaped projecting portion 15b of the surface ( (C) in the figure. At this time, as the material of the resin coating R, for example, a polyamide-based material can be used. In the case of this polyamide-based resin coating R, application by brush, application by spraying, or the like can be considered. Further, EPDM or the like can be used as the material of the rubber lining G.
In the valve body 10, the valve box 2 is provided in an area that contacts the inner surface of the valve box 2 when the valve is closed, and the peripheral area, other than the sliding contact with the guide 7 of the valve box 2. A rubber lining G is provided for sealing between the inner surfaces (see FIGS. 5 to 12).

  This soft seal gate valve V ′ is provided with a resin coating R on the entire surface of the core 11 of the valve body 10, and a portion of the surface where the rubber lining G is applied is sealed between the inner surface of the valve box 2 ( In the same manner, the corrosion resistance of the valve body is ensured, and the amount of the rubber additive leached out is less than that of the conventional surface of the valve body core 11 with the rubber lining. It can be effectively used as an environmental measure.

  Also in this embodiment, the resin coating R can be applied by powder coating of a resin rust preventive (epoxy resin), and the resin-coated core material 11 is loaded in a mold, and the cavity in the mold is filled. EPDM can be injected into the rubber lining G (G1, G2), and the rubber lining of the arc-shaped protrusion G1 and the drum-shaped protrusion G2 can be applied. At this time, the rubber lining G3 can also be provided in the concave portion 16, and the surface thereof can be a flat surface 16a. Further, the resin coating R can also be partial as shown in FIG.

In each of the above embodiments, the guide 7 is provided on the inner surface of the valve box 2 and the guide groove 14 into which the guide 7 is inserted is provided in the valve body 10. A guide groove 14 may be provided in the box 2.
As the rubber lining G, other than EPDM, the same kind of EPT, chloroprene rubber (CR), butyl rubber (IIR), fluorine rubber (FKM), silicone rubber (VMQ) and the like can be appropriately employed.
Further, as the resin coating R, other polyamide-based materials can be used in addition to the epoxy resin.
Furthermore, if a buffer layer made of rubber or the like is provided between the nut member (female screw piece) 5 and the resin-coated R-attached nut mounting portion 12, damage to the resin coating R due to friction with the nut member 5 can be prevented. The life of the resin coating R and the nut member 5 is improved. The buffer layer may be on either the nut member 5 side or the nut attachment portion 12 side. For example, after attaching a rubber sheet or the like to the nut member 5, the nut member 5 attached to the rubber sheet is attached to the nut attachment portion 12. Use means such as fitting. In addition, when the rubber lining G is applied also to the inner surface of the nut attachment portion 15, the resin coating R on the inner surface is not necessary, and the rubber lining G serves as the buffer layer.

  In the soft seal gate valves V and V ′ of the above-described embodiments, the nut member 5 screwed to the valve stem 3 is attached to the valve body 10, and the nut member 5 and the valve body 10 are integrated by rotating the valve stem 3. However, in the present invention, the nut member 5 is rotatably mounted on the lid 4 of the valve box 2 and the rotation of the valve stem 3 screwed to the nut member 5 is restricted. Thus, by rotating the nut member 5, it is also possible to adopt an external screw type in which the valve stem 3 and the valve body 10 attached thereto are linearly moved integrally. Even in this case, it is needless to say that the rubber lining G3 can be provided in the valve body concave portion 16 and the surface thereof can be a flat surface 16a.

Incidentally, it is needless to say that the resin coating R of the valve body 10 is not necessarily applied to the entire surface of the core material 11, and at least the rubber lining of the surface of the core material 11 as in the embodiment shown in FIG. 2. It is only necessary to cover the entire area where G is not applied. For example, when the resin coating R is applied to the surface of the core material 11 of the valve body 10, the core material is supported by a part of the region where the rubber lining G is applied thereafter (this portion is not resin-coated). The coating operation can be performed efficiently.
Further, when the resin coating R is not applied to the entire surface of the core material 11, it is preferable that the edges of the rubber lining G and the resin coating R overlap with each other. This may be set appropriately in consideration of adhesiveness and peelability. For example, the resin coating R is on the lower side.
Further, the rubber lining G is applied by other known means other than the above-described injection molding, for example, by sandwiching a corresponding portion (valve seat portion) of the core material between two plate-like rubbers, and applying heat press. Needless to say, it is possible to adopt a lining means.

DESCRIPTION OF SYMBOLS 1 Fluid passage 2 Valve box 2a Valve body accommodating part 3 Valve rod 4 Lid 5 Nut member 7 Guide 10 Valve body 11 Core material 13 Core material cylindrical part 14 Guide groove 16 Recess G Rubber lining G1 Arc-shaped part G2 of rubber lining G Rubber Drum portion G3 of lining G Rubber lining portion R of recess 16 Resin coating

Claims (7)

A valve body (10) that linearly moves in a direction orthogonal to the fluid passage (1) in the valve box (2) to open and close the fluid passage (1) is provided, and the valve box (10) is provided on the surface of the valve body (10). In the soft seal gate valve (V, V ′) with rubber lining (G) that forms a valve body valve seat that contacts and seals between the valve seats of 2),
The said valve body (10) gives the said rubber lining (G) to the surface of a metal casting core material (11), and the said rubber lining (G) is the valve seat of the said valve box (2). The core material (11) is subjected to a range where the sealing property can be ensured, and the portion other than the rubber lining (G) is exposed to the ground, and the exposed portion is subjected to a rust prevention treatment (R). A soft seal gate valve characterized by The valve shaft (3) in the orthogonal direction is inserted into the valve box (2), and the valve box (2) opens upward at the center in the flow direction of the fluid passage (1). And a lid (4) through which the valve rod (3) is inserted is attached to the opening edge of the valve body housing portion (2a). The outer peripheral surface of the valve body (10) and the valve box (2 ) Is formed on one of the inner circumferential surfaces of the above-mentioned orthogonal direction, and the other is formed with a groove (14) in the same orthogonal direction in which the guide (7) fits and slides. The valve stem (3) is threaded through the female thread piece (5) of 10), and the valve (3) is rotated to cause the valve (3) to slide through the fitting slide of the guide (7) and the groove (14). The soft seal gate valve according to claim 1, wherein the body (10) linearly moves in the orthogonal direction to open and close the fluid passage (1).
The core material (11) has a mounting portion (12) in a state where the female screw piece (5) is prevented from coming off at an upper portion of the cylindrical body portion (13), and the valve rod passes through the female screw piece (5). (3) enters the central space (13a) of the body part (13) and has the guide (7) or groove (14) on both sides of the body part (13), and the guides (7) or A required range around the central axis in the flow direction of the fluid passage (1) on the surface of the body (13) between the grooves (14) is an exposed portion of the core material background, and the rubber lining (G1, A soft-seal gate valve that is subjected to G2).   The exposed surface of the core material background on the surface and inner surface of the female screw piece mounting portion (12), the guide (7) surface or the inner surface of the groove (14), the inner surface of the trunk portion (13), and the surface of the trunk portion (13). The soft seal gate valve according to claim 2, wherein at least the antirust treatment (R) is performed.   A pair of protruding ridges (14a, 14a) opposed to each other in the orthogonal direction are formed on both side surfaces of the trunk portion (13), and the groove (14) is formed between the protruding ridges (14a, 14a). The rubber lining (G1, G2) is brought into the recess (16) between the protrusion (14a) and the body (13), and the surface of the rubber lining (G3) in the recess (16) is orthogonal to the above. The soft seal gate valve according to claim 2 or 3, wherein the soft seal gate valve is a plane along the direction.   The soft seal gate valve according to any one of claims 1 to 4, wherein the rust prevention treatment is performed by a resin coating (R).   6. The soft seal gate valve according to claim 5, wherein the resin coating (R) is made by powder coating of a resin rust inhibitor.   The resin coating (R) is formed by powder coating of a resin rust preventive agent by masking a portion to which the rubber lining (G) is applied, and the rubber lining (G) is injection-molded by a mold. The soft seal gate valve according to claim 6.

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