JP2007182948A - Spiral gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an improved spiral gasket capable of constituting a means therefor in a state of being excellent in productivity and advantageous to cost, for preventing leakage from a clearance by eliminating the clearance in a bending recessed part of a metallic belt. <P>SOLUTION: This spiral gasket is formed by winding the cross-sectional waveform metallic belt 1 and a belt-like filler material 2 in a spiral shape in a plurality of times in a mutually superposed state, and is constituted so that a place forming a deforming part 3 projecting in the outer diameter or inner diameter direction, exists by one place or more in a bending part 1a presenting a bent cross-sectional shape in the metallic belt 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spiral wound gasket formed by winding a metal strip having a corrugated cross section and a strip-like filler material in a state of being polymerized to each other in a spiral manner.

  In this type of spiral wound gasket, the filler material inserted to fill the gap between adjacent metal bands is made of a softer material than metal bands such as synthetic resin and expanded graphite. As shown in FIG. 1, in the use state after being compressed, the filler material cannot follow and deform in the bent concave portion of the metal band, and there is a possibility that a gap or a portion with a low density is generated. When such an inconvenience occurs, there is a possibility that the fluid may spirally leak through the gap or the like.

  Therefore, as a countermeasure, conventionally, as shown in FIG. 2 of the above-mentioned Patent Document 1, the auxiliary filler material is polymerized at a predetermined position of the filler material, whereby a gap or a portion having a low density is formed in the bent recess of the metal strip. As shown in FIG. 4 of Patent Document 2, a filler material having a convex section in which a convex portion is integrally formed at a portion corresponding to a bent concave portion of a metal band in the filler material is used. Means are taken. In addition, as disclosed in Patent Document 3 (see FIG. 2), a technique is also known in which a string-like body made of a fiber material or the like is wound around a bent recess of a metal band so that no gap is generated. It has been.

However, the means for separately providing an auxiliary filler as in Patent Document 1 and the means for forming the filler itself into a T-shaped cross section as in Patent Document 2 form the filler as well as between the metal bands. Both installations are time-consuming and disadvantageous in terms of production efficiency and cost. Moreover, in the means shown in Patent Document 3, it is difficult to equip the string-like body by being positioned in the bent concave portion of the metal strip in a lateral orientation, there is a problem in production efficiency, and a different material is attached. Therefore, the gap was not completely filled, and it was difficult to eliminate the leakage.
JP-A-60-188664 Japanese Patent Publication No. 2952764 JP-A-2-266164

  As described above, any of the conventional techniques has advantages and disadvantages, and there is room for further improvement. In other words, Patent Documents 1 and 2 are excellent in filling the bent concave portion of the metal band, but there is a problem that the production efficiency is slightly inferior and the price is high. In addition to being slightly inferior, leak prevention performance tends to be incomplete.

  In view of the above circumstances, the object of the present invention is to eliminate the gap in the bent recess of the metal band and prevent leakage therefrom, and the means therefor is configured in a state that is excellent in productivity and advantageous in terms of cost. And an improved spiral wound gasket that can be realized.

The invention according to claim 1 is a spiral gasket formed by winding a metal strip 1 having a corrugated cross-section and a strip-like filler material 2 in a state of being polymerized with each other in a spiral manner.
The bent portion 1a having a bent cross-sectional shape in the metal strip 1 has a portion where a deformed portion 3 protruding in the outer diameter or inner diameter direction is formed.

  The invention according to claim 2 is the spiral wound gasket according to claim 1, wherein the deformable portion 3 is a protruding portion 9 protruding in the inner diameter direction formed in the bent portion 1a that is convex in the outer diameter direction. It is characterized by this.

  The invention according to claim 3 is the spiral gasket according to claim 1, wherein the deformable portion 3 is one of the ridges 10, 12 that bulges in the outer diameter direction over the entire width of the metal strip 1. It is formed by the part.

  The invention according to claim 4 is the spiral wound gasket according to claim 2 or 3, wherein the deformable portion 3 is formed by press forming the metal strip 1. It is.

  According to a fifth aspect of the present invention, in the spiral wound gasket according to the second or third aspect, the deformable portion 3 is formed by welding or bonding a member made of a different material to the metal strip 1. It is characterized by being made.

  According to the first aspect of the present invention, although described in detail in the section of the embodiment, in a portion where the bent portion of the metal band has a deformed portion protruding in the outer diameter or inner diameter direction, the metal band is positioned on the outer diameter side or the inner diameter side. It is possible to avoid the formation of a gap between the bent recess of the metal strip or the filler material in the bent recess of the metal band having the deformed portion, and the fluid leaking into the gap between the bent recess and the filler material is deformed. The possibility of leakage due to the formation of a spiral gap can be eliminated.

  As a form for avoiding the formation of the gap, the following 1. ~ 4. The following configuration is conceivable. First, 1. In a means (see FIGS. 5 and 6) where there is a deformed portion protruding in the outer diameter direction at a bent portion that is convex toward the outer diameter side, a gap is formed in the bent concave portion formed on the inner diameter side of the metal strip located on the outer diameter side Can be avoided. 2. In the means (see FIGS. 1 and 7) where there is a deformed portion protruding in the inner diameter direction at the bent portion that is convex on the outer diameter side, there is a gap in the bent recess formed on the inner diameter side of the metal strip having the deformed portion. Can be avoided. 3. In the means [see FIG. 8 (a)] where there is a deformed portion protruding in the outer diameter direction at the bent portion that is convex toward the inner diameter side, there is a gap in the bent recess formed on the outer diameter side of the metal strip having the deformed portion. What can be done can be avoided. 4). In the means [see FIG. 8 (b)] where there is a deformed portion protruding in the inner diameter direction at the bent portion that protrudes toward the inner diameter side, a gap can be formed in the bent recess formed on the outer diameter side of the metal strip located on the inner diameter side. Can be avoided.

  In any of these cases, the means for preventing leakage is so slight that one or more deformed portions are formed on the metal band, so there is little or no reduction in production efficiency and cost increase. Can be. As a result, it is possible to prevent leakage from the bent recess of the metal strip, and to realize an improved spiral wound gasket that can be configured in a state that is excellent in productivity and advantageous in terms of cost. Can be provided.

  According to the invention of claim 2, the 1. The structure is specified, and the action of pushing the filler material located on the outer diameter side to the outer diameter side avoids the formation of a gap in the bent concave portion formed on the inner diameter side of the metal strip located on the outer diameter side. Can be made.

  According to the invention of claim 3, the 1. And 3. The structure is specified, and the action of pushing the filler material located on the outer diameter side to the outer diameter side avoids the formation of a gap in the bent concave portion formed on the inner diameter side of the metal strip located on the outer diameter side. It is possible to prevent the formation of a gap in the bent concave portion formed on the outer diameter side of the metal band having the deformed portion by the action of pushing the filler material located on the outer diameter side to the outer diameter side. Can do.

  According to the invention of claim 4, since the deformed portion is formed integrally with the metal strip by press forming, an excellent spiral gasket having the deformed portion is provided that is excellent in production efficiency and inexpensive. Can do.

  According to the invention of claim 5, since the deformed portion is formed by welding or bonding a member made of a material different from the metal band to the metal band, the metal band itself is a conventional one. This is advantageous in that it eliminates the need to change or modify equipment related to the production of metal strips.

  Embodiments of a spiral wound gasket according to the present invention will be described below with reference to the drawings. 1-3 is each figure regarding the spiral wound gasket of Example 1, FIG. 4 is a principle figure which shows the example of a manufacturing method of a metal strip. 5 to 7 are a perspective view and a cross-sectional view of the main part showing the deformation part of Examples 2 to 4, respectively, and FIG. 8 is a cross-sectional view of the main part showing the deformation part of the W-shaped spiral wound gasket. In each drawing, the thickness of the filler material, the winding interval of the metal band, etc. are exaggerated more than the actual dimensional balance for understanding the drawings.

[Example 1]
The spiral wound gasket A according to the first embodiment is used for applications where high airtightness is required, such as a piping system for fluids such as gas and liquid such as LNG and LPG, or for applications where it is difficult to ensure a large tightening pressure. It is preferably used. As an example, as shown in FIG. 2, it is known to be used at a connection location between pipe flanges 4 and 5.

  That is, it is interposed between the flange portion 4A of the first piping flange 4 and the flange portion 5A of the second piping flange 5, and a plurality of flange portions 4A and 5A are provided at equal angles in the circumferential direction. The bolts and nuts 6 of the spiral gasket A are tightened and fixed until the thickness of the spiral gasket A is compressed by a specified amount (or with a specified tightening torque), whereby the pipe flanges 4 and 5 are connected to each other. Are connected so that the internal flow paths 4a and 5a are connected in a sealed state.

  As shown in FIGS. 1 and 2, the spiral wound gasket A has a large number of cross-sectional corrugations, more specifically, a state in which the cross-section of the metal strip 1 and the strip-shaped filler material 2 are superposed on each other. One or more locations where the deformed portion 3 that partially protrudes in the inner diameter direction is formed in the bent portion 1 a that is wound in a spiral shape and has a bent cross-sectional shape in the metal strip 1. It is what. Specifically, the bending portion 1a is a portion that bends to the maximum in the radial direction (in the first embodiment, “maximum”). In addition, when the cross-sectional shape is a waveform having a bent portion on both the outer diameter side and the inner diameter side, such as a “W” shape, the bent portion protruding to the outer diameter side is a “maximum” bent portion. The bent portion that protrudes toward the inner diameter side is a “minimal” bent portion, and the present invention includes both bent portions.

  A metal strip (referred to as a “hoop”) 1 is formed by pressing a steel plate (eg, stainless steel plate), and the cross-sectional shape is substantially “koku” composed of short straight portions 1t and 1t at both ends and a central V-shaped portion 1A. "" And each end of winding is fixed by spot welding to adjacent metal strips 1 on the outer diameter side or inner diameter side. A central portion of the V-shaped portion 1A is a bent portion 1a, and a concave portion formed in the bent portion 1a is a bent concave portion 1b.

  The metal strip 1 is produced by a manufacturing method as shown in FIG. 4, for example. That is, a pair of rotary roller-shaped first and second press dies 7 and 8 having different surface hardnesses are disposed in close proximity to each other and are rotatably supported. A flat plate is formed between the press dies 7 and 8. By passing the stainless steel plate 1 ′, the metal strip 1 in a curved state in which the cross section is formed into a predetermined “<” shape and is bent in a direction approaching one press die 7 is continuous. It is formed. Note that the method for creating the metal strip 1 may be other than this method.

  In FIG. 4, the first press die 7 that is rotatable about the axis P <b> 1 drawn on the upper side is a concave type having a recessed portion 7 a in which the center of the outer peripheral portion is recessed on the inner diameter side, and is drawn on the lower side. Each of the second press dies 8 that can freely rotate about the axis P2 is formed into a convex shape having a protruding portion 8a with the center of the outer peripheral portion protruding to the outer diameter side. Due to the hardness difference between the surfaces of the first and second press molds 7 and 8, the metal strip 1 after the rotary press molding is in a curved state with a bending ridge in the direction approaching the second press mold 8 as shown in the figure, for example. Be pushed out.

  As shown in FIG. 4, the convex part 7A which protruded in the outer diameter direction is formed in one place (a plurality of places may be sufficient) in the circumferential direction in the left and right central part of the recessed part 7a of the first press die 7. (A concave mold portion 8A is formed at a corresponding position of the second press die 8). When this intersects with the second press die 8, a protruding portion protruding in the inner diameter direction at the bent portion 1a of the V-shaped portion 1A The deformed portion 3 is formed with 9. That is, in this case, the protrusions 9 that are the deformed portions 3 in the metal band 1 are formed every time the first press die 7 makes one rotation, that is, at regular intervals. Therefore, if the spiral band gasket A is created by winding the metal strip 1 with bending folds together with the filler material 2 into a spiral shape, the protrusions 9 are formed at a plurality of locations at equal distances in the circumferential direction. It becomes.

  As shown in FIG. 3, the protrusion 9 has a shape like a hole that causes the bent portion 1 a of the V-shaped portion 1 </ b> A to be partially recessed in the opposite direction, and the metal band 1 at the center in the width direction of the metal band 1. 1 has a long elliptical plan view shape along the longitudinal direction of 1. The projecting amount of the projecting portion 9 is in a very close state (eg, 0.5 mm) in a free state (a state formed in the spiral wound gasket A) so as not to contact the apex portions of the adjacent bent portions 1a on the inner diameter side. (See FIG. 1). Then, even in the state where it is actually assembled as a seal and tightened to reduce the thickness of the spiral wound gasket A (the state where the bending angle of the V-shaped portion 1A becomes tighter), the protrusion 9 and the filler 2 There is no gap between them, and it is possible to reliably prevent leakage at that portion.

  The filler 2 is an expanded graphite tape formed by pressurizing expanded graphite particles so as to be integrated with each other and forming a narrow band shape (tape shape) having a predetermined thickness, and is adjacent to the outer diameter side of the metal band 1. It is formed into a spiral gasket A shown in FIG. 2 and the like by being polymerized into a cylindrical body and wound together in a spiral shape. Since this expanded graphite filler 2 is a known one, further explanation is omitted.

  Now, in the spiral wound gasket A of Example 1, the deformed portion 3 of the metal strip 1 is a protruding portion 9 in the inner diameter direction formed at the bent portion 1a, and therefore the metal adjacent to the protruding portion 9 on the inner diameter side. Since the distance between the belt 1 and the belt 1 is extremely narrow, it is possible to eliminate a gap from the filler material 2 interposed there. Therefore, in a portion where the protrusion 9 is not formed, a gap s (see FIGS. 2 and 6) formed between the bent concave portion 1b of the metal strip 1 and the filler material 2 on the inner diameter side thereof is transmitted. It is possible to prevent the fluid from leaking at the projecting portion 9.

  As a result, a protrusion 9 (deformed portion 3) that partially projects in the inner diameter direction at the bent portion 1a of the metal band 1 is formed by a device that is simultaneously formed in the production process from the band plate 1 ′ to the metal band 1. By forming more than one part, the production efficiency is excellent, the product cost is not increased or the state is extremely small, and the gap s leading to the risk of leakage, that is, between the bent portion 1a of the metal strip 1 and the filler material 2 is formed. The structure which interrupted | blocks the clearance gap s on the way was able to be taken.

  In the spiral wound gasket A of Example 1, the deformed portion 3 is formed in a total of about 10 locations, and even if it is considered that the working tightening pressure is not uniform on the spiral wound gasket A, the bent concave portion 1b of the metal strip 1 is formed. The performance to prevent leakage from the tank is sufficiently exhibited. In the spiral gasket A having a large diameter and a larger number of windings of the metal strip 1, it is considered necessary to increase the total number of deformed portions 3 as well.

[Example 2]
As shown in FIG. 5, the spiral wound gasket A <b> 2 according to the second embodiment is a part of the outer convex strip 10 in which the deformed portion 3 bulges out in the outer diameter direction in the state of covering the entire width of the metal strip 1, that is, the outer convex. It is formed in the part located in the bending | flexion site | part 1a in the strip | line 10, and other than that is the same as the spiral wound gasket A of Example 1. FIG. In this case, the outer convex strip 10 (the deformed portion 3) acts to push the filler material 2 positioned on the outer diameter side into the concave portion of the adjacent metal strip 1 on the outer diameter side, thereby bending the concave portion. It can regulate so that there may be no gap in 1b. In addition, the deformation | transformation part 3 which consists of the outer protruding item | line 10 formed only in the bending | flexion site | part 1a part which omitted both ends of the outer protruding item | line 10 may be sufficient.

Example 3
As shown in FIG. 6, the spiral wound gasket A <b> 3 according to Example 3 has a deformed portion 3 formed by a convex top portion 11 that partially protrudes in the outer diameter direction at a bent portion 1 a that exhibits a bent cross-sectional shape in the metal band 1. Other than that, it is the same as the spiral wound gasket A of the first embodiment. In this case, the convex top 11 acts to extrude the filler material 2 positioned on the outer diameter side and push it into the bent recess 1b of the metal strip 1 on the outer diameter side, so that there is no gap in the bent recess 1b. Can be regulated.

Example 4
As shown in FIG. 7, the spiral gasket A <b> 3 according to Example 4 is a part of the inner ridge 12 in which the deformed portion 3 bulges in the inner diameter direction in the state of extending over the entire width of the metal strip 1, that is, the inner ridge. 12 is the same as the spiral wound gasket A of the first embodiment. In this case, the inner ridge 12 (the deformed portion 3) can be regulated so that a gap is not formed between the inner ridge 12 by pressing the filler material 2 positioned on the inner diameter side against the inner diameter side. it can.

[Description of various means to eliminate gaps in bent recesses]
Here, four types of forms for avoiding the formation of the gap s will be described. First, the configuration shown in FIG. 5 and FIG. It is a means which has the deformation | transformation part 3 which protrudes in an outer-diameter direction in the bending part 1a which becomes convex on the outer-diameter side, pushes the filler material 2 located in an outer-diameter side to an outer-diameter side, and is located in the outer-diameter side It is possible to avoid the formation of a gap s in the bent concave portion 1b formed on the inner diameter side of the metal strip 1. Next, the configuration shown in FIG. 1 and FIG. There is a deformed portion 3 projecting in the inner diameter direction at the bent portion 1a that is convex toward the outer diameter side, and the filler 2 positioned on the inner diameter side is pushed out toward the inner diameter side, and the metal band 1 having the deformed portion 3 It is possible to avoid the formation of a gap s in the bent recess 1b formed on the inner diameter side of the.

  Then, the configuration shown in FIG. A metal band having a deformed portion 3 projecting in the outer diameter direction at a bent portion 1a that is convex toward the inner diameter side, and extruding the filler material 2 positioned on the outer diameter side toward the outer diameter side. It is possible to avoid the formation of a gap s in the bent concave portion 1b formed on the outer diameter side of 1. Further, the configuration shown in FIG. There is a deformed portion 3 protruding in the inner diameter direction at the bent portion 1a that protrudes toward the inner diameter side, and a gap s is formed in the bent concave portion 1b formed on the outer diameter side of the metal strip 1 located on the inner diameter side. Can be avoided. 1 above. And 2. Means for the clearance s of the bending recess 1b at the maximum bending portion 1a, and 3. And 4. This means can eliminate the gap s of the bent concave portion 1b in the minimum bent portion 1a. 1, 5, 6, 7 and 8, P is the axis of the spiral wound gasket A.

[Comparison between the product of the present invention and the conventional product]
Using a spiral wound gasket having dimensions of an inner diameter of 90 mm, an outer diameter of 110 mm, and a thickness of 4.5 mm, a test for determining the relationship between the clamping pressure and leakage was performed. As test conditions, the tightening pressure was measured when the amount of leakage per minute was 0.01 cc / min. There are three test products: Example 1, Example 2, and a conventional product (no deformation part). The measured clamping pressure (unit: N / mm ² ) was 20 for Example 1, 25 for Example 2, and 45 for the conventional product. Also from this test, it can be recognized that the present invention having the deformed portion 3 exhibits an excellent leakage prevention function.

[Another Example]
The cross-sectional shape of the metal strip 1 may be a substantially “Z” shape, a substantially “Z” shape, a “W” shape shown in FIG. The filler material 2 can be a material other than expanded graphite such as a synthetic resin material. The deformable portion 3 may be formed as a member made of a material other than the metal strip 1, such as a metal, a synthetic resin, or the like, and may have a shape other than those of the first to fourth embodiments.

Partially cutaway perspective view showing the structure of a spiral wound gasket (Example 1) Sectional drawing which shows one use condition of the spiral wound gasket of FIG. 1 is a perspective view of a part of a metal strip showing a deformed portion according to Example 1 of FIG. Principle diagram of the main part showing a manufacturing example of a spiral wound gasket The perspective view of a partial notch of the metal strip showing the deformed portion according to the second embodiment Sectional drawing of the spiral wound gasket which shows the deformation | transformation part by Example 3 Sectional drawing of the spiral wound gasket which shows the deformation | transformation part by Example 4 The cross section shows a deformed portion in a metal band having a W-shaped cross section, where (a) is a deformed portion that protrudes to the outer diameter side at the bent portion on the inner diameter side, and (b) is a deformation that protrudes to the inner diameter side at the bent portion on the inner diameter side Part

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal strip 1a Bending part 2 Filler material 3 Deformation part 9 Protrusion 10,12 Convex strip A Spiral wound gasket

Claims (5)

A spiral gasket formed by winding a metal strip having a corrugated cross section and a strip-shaped filler material in a state of being polymerized with each other in a spiral shape,
A spiral wound gasket in which a bent portion having a bent cross-sectional shape in the metal strip has a portion where a deformed portion protruding in the outer diameter or inner diameter direction is formed.   2. The spiral wound gasket according to claim 1, wherein the deforming portion is a protruding portion protruding in an inner diameter direction formed in the bent portion that is convex in an outer diameter direction.   2. The spiral wound gasket according to claim 1, wherein the deformable portion is formed by a part of a protruding strip that bulges in an outer diameter direction in a state extending over the entire width of the metal strip.   4. The spiral wound gasket according to claim 2, wherein the deformable portion is formed by applying press molding to the metal strip. 5. 4. The spiral wound gasket according to claim 2, wherein the deformable portion is formed by welding or bonding a member made of a different material to the metal band.

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