Flange joint leakage prevention device

Abstract

To provide a leakage prevention device for flange joints that offers excellent sealing performance and ease of installation. [Solution] The leak prevention device 1 comprises a strip-shaped packing 3 arranged in an annular shape to cover the flange joint portion of a fluid pipe, and an annular mounting fixture 4 that is fitted onto the flange joint portion via the packing 3. The packing 3 has a dividing surface 3S and a first packing end 3X and a second packing end 3Y divided by the dividing surface 3S. The mounting fixture 4 has a dividing portion 4S and a first connecting end 4X and a second connecting end 4Y that are connected to each other at the dividing portion 4S. The first packing end 3X protrudes circumferentially from the inner circumferential surface of the first connecting end 4X to the inner circumferential surface of the second connecting end 4Y. The mounting fixture 4 has a pair of side walls 42 that face each other with the packing 3 sandwiched in the axial direction, and the pair of side walls 42 protrude circumferentially from the inner circumferential surface of the first connecting end 4X.

Description

Technical Field

[0001] The present disclosure relates to an apparatus for preventing leakage of fluid at a flange joint of a fluid pipe.

Background Art

[0002] In a flange joint of a fluid pipe, due to external forces such as earthquakes or the effects of aging, there is a risk that fluid may leak from the gap between the flanges. In order to prevent such fluid leakage or to prevent fluid leakage that has already occurred, a leakage prevention device is attached to the flange joint (see, for example, Patent Document 1). The leakage prevention device includes a strip-shaped packing arranged annularly so as to cover the flange joint, and an annular fixture externally fitted to the flange joint through the packing.

[0003] In the leakage prevention device, if the portion including the split surface of the packing is not stably held at the split portion of the fixture, the sealing performance may thereby decrease. For this reason, in the leakage prevention device described in Patent Document 1, in order to maintain the sealing performance, a metal holding plate straddling the split portion of the fixture is arranged between the packing and the fixture. However, in order to improve the workability when attaching the leakage prevention device to the flange joint, a structure that can ensure the sealing performance without using special additional parts such as a holding plate is desirable.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a leakage prevention device for a flange joint that is excellent in sealing performance and workability during attachment. [Means for solving the problem]

[0006] The flange joint leakage prevention device of the present disclosure comprises a strip-shaped packing arranged in an annular manner to cover the flange joint of a fluid pipe, and an annular mounting fixture fitted onto the flange joint via the packing. The packing has a dividing surface formed at least at one location in the circumferential direction, and a first packing end and a second packing end divided by the dividing surface. The mounting fixture has a dividing portion formed at least at one location in the circumferential direction, and a first connecting end and a second connecting end connected to each other at the dividing portion. The first packing end protrudes circumferentially from the inner circumferential surface of the first connecting end to the inner circumferential surface of the second connecting end. The mounting fixture has a pair of side walls that face each other with respect to the packing in the axial direction. The pair of side walls protrude circumferentially from the inner circumferential surface of the first connecting end. [Brief explanation of the drawing]

[0007] [Figure 1] Front view showing the leakage prevention device for flange joints. [Figure 2] Side view of the leak prevention device in Figure 1. [Figure 3] Cross-sectional view AA in Figure 1 [Figure 4] BB cross-section diagram in Figure 1 [Figure 5] Cross-sectional view of packing and mounting fixture [Figure 6] Exploded view of the leak prevention device [Figure 7] Perspective view of the first connecting end, seen from the radially inward side. [Figure 8] Perspective view of the second connecting end, seen from the radially inward side. [Figure 9] Two-view drawing of a packing piece [Figure 10] Two-view drawing showing the dividing surface of the packing. [Figure 11] Two-view drawing showing the dividing surface of the packing. [Figure 12] Two-view drawing showing the dividing surface of the packing. [Figure 13] A view of the divided section with the packing removed, seen from the radially inner side. [Figure 14] A perspective view showing how the leak prevention device is attached to the flange joint. [Figure 15] A perspective view showing how the leak prevention device is attached to the flange joint. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described with reference to the drawings.

[0009] Figure 1 is a front view showing the leak prevention device 1 of this embodiment. Figure 2 is a side view of the leak prevention device 1. Figure 3 is a cross-sectional view AA of Figure 1. Figure 4 is a cross-sectional view BB of Figure 1. Figure 5 is a cross-sectional view of the packing 3 and the fitting 4 along the line AA of Figure 1. Regarding the terminology used to describe direction, the circumferential direction refers to the direction around the pipe axis of the fluid pipe (water pipes P1, P2 in this embodiment). The radial direction is the direction along the diameter of the fluid pipe. The side of the fluid pipe closer to the pipe axis is the radially inward direction, and the side of the fluid pipe further away from the pipe axis is the radially outward direction. The axial direction is the direction parallel to the pipe axis of the fluid pipe.

[0010] The leak prevention device 1 is attached to a flange joint 10 where two water pipes P1 and P2, which are fluid pipes, are flange-jointed to each other. The water pipes P1 and P2 are, for example, ductile cast iron pipes. At the flange joint 10, a pair of flanges 11 and 12 formed at the ends of the water pipes P1 and P2 are fastened together by fasteners 20. The fasteners 20 are attached at multiple locations in the circumferential direction (eight locations in this embodiment). As shown in Figures 3 and 4, an annular gasket 13 is interposed between the pair of flanges 11 and 12, but is not limited to this. A gap 14 is formed between the flanges 11 and 12, opening radially outward.

[0011] The fastener 20 includes a bolt 21 inserted through the bolt holes of the flanges 11, 12 and a nut 22 screwed onto the bolt 21, and the flanges 11, 12 are clamped between the head of the bolt 21 and the nut 22. The fastener 20 further includes a sealing material 23 for sealing the gap of the bolt hole, a metal water stop ring 24 covering the sealing material 23, and a spacer 25 used for position adjustment of the bolt 21 and the nut 22. The sealing material 23 is formed with fin portions 23f (see FIG. 15) that enter the bolt holes respectively. The nut 22 may be changed to a bag nut (cap nut), or a part or all of the spacer 25 may be omitted.

[0012] In the flange joint portion 10, when the flanges 11, 12 are separated from each other due to an external force such as an earthquake or the influence of aging, fluid may leak from the gap 14 (i.e., water leakage may occur). Therefore, in order to prevent water leakage from the gap 14 in advance or to prevent water leakage that has already occurred, the leakage prevention device 1 is attached to the flange joint portion 10. When the flanges 11, 12 are separated from each other, water leakage from their bolt holes is also a concern, but in this embodiment, the fastener 20 provided with the sealing material 23 prevents such water leakage from the bolt holes.

[0013] The leakage prevention device 1 includes a strip-shaped packing 3 annularly arranged so as to cover the flange joint portion 10, and an annular fixture 4 externally fitted to the flange joint portion 10 through the packing 3. The packing 3 seals the gap 14 along the circumferential direction, and the fixture 4 presses the packing 3 against the outer peripheral surfaces of the flanges 11, 12. The packing 3 is formed of an elastic material such as rubber. The fixture 4 is formed of a material harder than the packing 3, preferably a metal material such as ductile cast iron.

[0014] In this embodiment, the packing 3 has a belt-shaped main body 31 including an outer peripheral surface 3a, and a plurality (three in this embodiment) of ridges 32 to 34 protruding radially inward and extending in the circumferential direction. The centrally located ridge 32 closes the gap 14, and the ridges 33 and 34 located on both sides thereof are in close contact with the outer peripheral surfaces of the flanges 11 and 12. The ridges 32 to 34 each have a semi-circular cross-sectional shape and are provided integrally with the main body 31. A flat portion 3f is formed between the ridge 32 and the ridges 33 and 34 so that interference between the ridges is suppressed even when the packing 3 is strongly clamped. The semi-circular radius of curvature of the ridge 32 is larger than the semi-circular radius of curvature of the ridges 33 and 34. The thickness T1 of the ridge 32 is larger than the thickness T2 of the ridges 33 and 34.

[0015] The width W2 of the packing 3 is smaller than the width W1 of the flange joint portion 10, but is not limited thereto. A circumferentially extending gap 30 is formed between a pair of side walls 42, which will be described later, and the packing 3. The gap 30 serves as a margin for allowing bulging deformation of the main body 31. The main body 31 includes protruding portions 35 that protrude axially more than the ridges 33 and 34 on both sides. The inner peripheral surface of the protruding portion 35 is inclined radially inward toward the axial center of the packing 3. According to such a configuration, when the packing 3 is strongly clamped, it becomes difficult for the ridges 33 and 34 to deform and escape outward, and the sealing performance is enhanced. The thickness of the protruding portion 35 is larger than half of the maximum thickness T1 of the packing 3, which is effective in suppressing the deformation of the ridges 33 and 34 described above. Note that the cross-sectional shape of the packing 3 is not limited to this, and various modifications can be adopted.

[0016] The mounting fixture 4 has a belt-shaped body 41 including an inner circumferential surface 4a, and a pair of side walls 42 provided at both axial ends of the body 41. The inner circumferential surface 4a extends along the circumferential direction and is in contact with the outer circumferential surface 3a of the packing 3. However, the inner circumferential surface 4a is missing at the divided portion 4S described later and is not continuous in an annular shape. Therefore, at the divided portion 4S, the inner circumferential surface 4a of the mounting fixture 4 does not come into contact with the outer circumferential surface 3a of the packing 3. The pair of side walls 42 protrude radially inward from the inner circumferential surface 4a and extend along the circumferential direction. The mounting fixture 4 is provided with an extension portion 43 that extends radially inward and can interfere with the fastener 20 in the circumferential direction. This restricts the relative rotation of the mounting fixture 4 with respect to the water pipes P1 and P2.

[0017] Figure 6 is an exploded view of the leak prevention device 1. The packing 3 has a dividing surface 3S and a first packing end 3X and a second packing end 3Y separated by the dividing surface 3S. The mounting fixture 4 has a dividing portion 4S and a first connecting end 4X and a second connecting end 4Y connected to each other by the dividing portion 4S. The dividing surface 3S and the dividing portion 4S are each formed at two locations in the circumferential direction. A fastener 5 is attached to the dividing portion 4S. The fastener 5 has a bolt 51 inserted through an extension portion 44 that extends radially and a nut 52 that is screwed onto the bolt 51. The mounting fixture 4 is configured to reduce in diameter when the fastener 5 is tightened, pressing the packing 3 toward the outer circumferential surface of the flanges 11 and 12.

[0018] Figure 7 is a perspective view of the first connecting end 4X from the radially inward side. Figure 8 is a perspective view of the second connecting end 4Y from the radially inward side. Figures 7 and 8 show (A) the state with the packing 3 installed and (B) the state with the packing 3 removed, respectively. As shown in Figures 1 and 6-8, the first packing end 3X protrudes circumferentially from the inner circumferential surface 4a of the first connecting end 4X to the inner circumferential surface 4a of the second connecting end 4Y. With this configuration, the portion of the packing 3 including the dividing surface 3S is positioned on the inner circumferential surface 4a of the second connecting end 4Y and is stably held, resulting in excellent sealing performance. The mounting fixture 4 has a pair of side walls 42 that face each other with the packing 3 sandwiched in the axial direction, and these pair of side walls 42 protrude circumferentially from the inner circumferential surface 4a of the first connecting end 4X. This configuration suppresses lateral bending (a phenomenon in which the first packing end 3X protruding from the inner circumferential surface 4a of the first connecting end 4X is bent along the axial direction), thus improving workability during installation.

[0019] The packing 3 is constructed by connecting a plurality of packing pieces 3P (two in this embodiment) in the circumferential direction, and each of the plurality of packing pieces 3P has a first packing end 3X and a second packing end 3Y. Each of the plurality of packing pieces 3P extends in an arc shape along the circumferential direction. The mounting fixture 4 is constructed by connecting a plurality of divided pieces 4P (two in this embodiment) in the circumferential direction, and a packing piece 3P is attached to each of the plurality of divided pieces 4P. The divided pieces 4P are connected to other divided pieces 4P adjacent to each other in the circumferential direction via fasteners 5. Extended portions 44 through which bolts 51 are inserted are provided at both ends of each of the plurality of divided pieces 4P.

[0020] Figure 9 is a two-view drawing of a packing piece 3P. An annular packing 3 is formed by connecting these packing pieces 3P in the circumferential direction. As previously described, each packing piece 3P has a first packing end 3X and a second packing end 3Y. Both the first packing end 3X and the second packing end 3Y are formed in a tapered shape with gradually decreasing thickness. The first packing end 3X of a packing piece 3P is joined to the second packing end 3Y of another packing piece 3P adjacent to that packing piece 3P in the circumferential direction, overlapping in the radial direction. The first packing end 3X includes an inclined surface 3Xt that is inclined with respect to the radial direction and faces radially outward. The second packing end 3Y includes an inclined surface 3Yt that is inclined with respect to the radial direction and faces radially inward, overlapping and in close contact with the inclined surface 3Xt.

[0021] When the fastener 5 is tightened and the mounting fixture 4 is reduced in diameter, the packing 3 is reduced in diameter as the inclined surfaces 3Xt and 3Yt slide against each other, and the inner surface of the packing 3 is pressed firmly against the outer surface of the flanges 11 and 12. With this configuration, the first packing end 3X and the second packing end 3Y are firmly joined to each other, so sealing performance is ensured even if the application of adhesive to the dividing surface 3S is omitted. In this case, the ends of the packing 3 can be joined together without adhesive at the construction site, so the workability during installation is greatly improved. Moreover, since the inner diameter of the packing 3 can be finely adjusted by the sliding of the inclined surfaces 3Xt and 3Yt, it is less affected by dimensional tolerances and radial misalignment of the flanges 11 and 12, and the packing 3 can be closely fitted to the outer surface of the flanges 11 and 12 to improve sealing performance.

[0022] Figures 10-12 show the dividing surface 3S as viewed from the inside in the axial direction (A) and radial direction (B), respectively. When the outer circumference lengths of flanges 11 and 12 are approximately the same as the effective length of packing 3, the inclined surfaces 3Xt and 3Yt abut each other without misalignment, as shown in Figure 10. The end faces of the protrusions 32-34 at the first packing end 3X coincide with the end faces of the protrusions 32-34 at the second packing end 3Y. In addition, the inner circumference of packing piece 3P is positioned flush (in the same plane) with the inner circumference of the adjacent packing piece 3P. The effective length of packing 3 is the design inner circumference length of the annularly formed packing 3, and corresponds to the sum of the inner circumference lengths of each packing piece 3P that constitutes packing 3.

[0023] If the outer diameters of flanges 11 and 12 are relatively small, and the outer circumference length of flanges 11 and 12 is smaller than the effective length of packing 3, a portion C1 is formed where the tip of the first packing end 3X overlaps the inner circumference surface of the second packing end 3Y, and a portion C2 is formed where the tip of the second packing end 3Y overlaps the outer circumference surface 3a of the first packing end 3X, as shown in Figure 11. However, since the inclined surfaces 3Xt and 3Yt can slide against each other, there is little concern that these portions C1 and C2 will be excessively compressed. Furthermore, since the packing 3 is compressed from the radially outward direction by the mounting fixture 4, these portions C1 and C2 do not adversely affect the sealing performance. In such cases, the effective length of packing 3 may be, for example, 101-102% of the outer circumference length of flanges 11 and 12.

[0024] If the outer diameters of flanges 11 and 12 are relatively large, and the outer circumference length of flanges 11 and 12 is greater than the effective length of packing 3, then a thin portion C3 is formed where the tip of the first packing end 3X does not reach the inner circumference surface of the second packing end 3Y, and a thin portion C4 is formed where the tip of the second packing end 3Y does not reach the outer circumference surface 3a of the first packing end 3X, as shown in Figure 12. However, since the degree of thinning in these portions C1 and C2 is minute, sufficient sealing performance can be obtained by compressing the packing 3 from the radially outer side by the mounting fixture 4. Nevertheless, in order to ensure sufficient compression of the packing 3, it is preferable to be in the state shown in Figures 10 and 11.

[0025] Furthermore, not only when the inclined surface 3Xt and the inclined surface 3Yt are not misaligned on the dividing surface 3S as shown in Figure 10, but also when they are misaligned as shown in Figures 11 and 12, the dividing surface 3S abuts the outer circumferential surface of the flanges 11 and 12 at an angle (in an arc shape along the semicircular cross-section), and the protrusions 33 and 34 on both sides abut and are compressed against the outer circumferential surface of the flanges 11 and 12, while the side surface of the central protrusion 32 abuts against the edge of the flanges 11 and 12 (see Figures 3 and 4). Therefore, even if a step is created between the flanges 11 and 12, the packing 3 can absorb the step and properly stop water flow.

[0026] In this embodiment, the inclined surface 3Xt and the inclined surface 3Yt each include the end faces of the protrusions 32 to 34. Therefore, at the divided surface 3S, the end faces of the protrusions 32 to 34 of the first packing end 3X and the end faces of the protrusions 32 to 34 of the second packing end 3Y overlap and adhere closely to each other radially, improving sealing performance. The ratio of the thickness of the overlapping portion of the inclined surfaces 3Xt and 3Yt to the maximum thickness T1 of the packing 3 (see Figure 5) is preferably 80% or more, more preferably 90% or more, and most preferably 100%, as in this embodiment. If the thickness increases, it is preferably 120% or less, and more preferably 110% or less. It is preferable that both the inclined surface 3Xt and the inclined surface 3Yt are formed extending from the outer circumferential surface 3a to the inner circumferential surface of the packing 3. The maximum thickness T1 of the packing 3 is, for example, 15 to 25 mm.

[0027] In this embodiment, the inclined surface 3Xt forms an acute angle with respect to the inner circumferential surface of the packing 3 and an obtuse angle with respect to the outer circumferential surface 3a of the packing 3. The inclined surface 3Yt forms an obtuse angle with respect to the inner circumferential surface of the packing 3 and an acute angle with respect to the outer circumferential surface 3a of the packing 3. With this configuration, a wide contact area between the inclined surface 3Xt and the inclined surface 3Yt can be secured, effectively improving the sealing performance. In Figure 9, angles θ1 and θ3 are both less than 90 degrees, for example, between 15 and 45 degrees. Angles θ2 and θ4 are both greater than 90 degrees, for example, between 135 and 165 degrees. Angles θ1 to θ4 are measured with the packing 3 placed on a flat surface and stretched in a straight line.

[0028] Figure 13 is a view of the divided portion 4S from the radially inner side with the packing 3 removed. As shown in Figures 7, 8 and 13, in this embodiment, the divided portion 4S is formed in a comb-like shape, and the first packing end 3X and the second packing end 3Y have complementary shapes that fit together. The degree of these fittings (the degree of interlocking) changes depending on the diameter dimensions of the flanges 11 and 12 and the tightening of the fastener 5. With this configuration, relative positional displacement between the divided pieces 4P in the axial direction can be suppressed. In addition, if any of the multiple divided pieces 4P are facing the opposite direction, the comb-like ends will not fit together, thus preventing incorrect combinations and connections.

[0029] The first connecting end 4X has a pair of side teeth 45 extending along a pair of side walls 42, and a center tooth 46 located midway between the pair of side teeth 45. The second connecting end 4Y has a pair of middle teeth 47 positioned between the pair of side teeth 45 and the center tooth 46. The side teeth 45 and the center tooth 46 protrude circumferentially from the end face of the first connecting end 4X, and the middle teeth 47 protrude circumferentially from the end face of the second connecting end 4Y. A pair of side walls 42 are integrally provided radially inward of the pair of side teeth 45. Each of the pair of side walls 42 extends to the tip of the side teeth 45. Neither the center tooth 46 nor the middle teeth 47 protrude radially inward from the inner circumferential surface 4a.

[0030] As shown in Figures 2 and 7, the first packing end 3X protrudes circumferentially from the inner circumferential surface 4a of the first connecting end 4X, and is therefore a free end that is not fixed to the mounting fixture 4. Consequently, when attaching it to the flange joint 10, it may bend laterally (a phenomenon in which it bends along the axial direction), which may complicate the work at the construction site. In contrast, according to the leakage prevention device 1 of this disclosure, as described above, the pair of side walls 42 that protrude circumferentially from the inner circumferential surface 4a of the first connecting end 4X can suppress the lateral bending of the first packing end 3X, thereby improving workability during installation. In this embodiment, the second packing end 3Y does not protrude circumferentially from the inner circumferential surface 4a of the second connecting end 4Y. As a result, the portion of the packing 3 including the dividing surface 3S is properly positioned on the inner circumferential surface 4a of the second connecting end 4Y and held stably, thus ensuring better sealing performance.

[0031] As shown in Figure 8, in this embodiment, the tip of the second packing end 3Y is aligned with the edge of the inner circumferential surface 4a of the second connecting end 4Y in the circumferential direction. With this configuration, the dividing surface 3S is positioned near the dividing portion 4S, and the circumferential direction of the portion including the dividing surface 3S is brought closer to the axial direction of the bolt 51. As a result, the force that brings the divided pieces 4P closer together when the fastener 5 is tightened (a force acting along the axial direction of the bolt 51) is easily transmitted to the dividing surface 3S, and the first packing end 3X (its inclined surface 3Xt) is strongly pressed against the second packing end 3Y (its inclined surface 3Yt). The tip of the second packing end 3Y may be positioned away from the edge of the inner circumferential surface 4a of the second connecting end 4Y, but it is preferable that it does not protrude circumferentially from that edge.

[0032] It is preferable that the second packing end 3Y is bonded to the inner circumferential surface 4a of the second connecting end 4Y. This positions the packing 3 relative to the mounting fixture 4, improving workability during installation. For example, adhesive may be applied to a range Ry (shaded area in Figure 8(B)) having a predetermined circumferential length from the edge of the inner circumferential surface 4a of the second connecting end 4Y. Similarly, adhesive may be applied to a range Rx (shaded area in Figure 7(B)) having a predetermined circumferential length from the edge of the inner circumferential surface 4a of the first connecting end 4X, and to the intermediate area between range Rx and range Ry, thereby setting three bonding ranges for each segmented piece 4P. Alternatively, the entire inner circumferential surface 4a of the mounting fixture 4 may be used as the bonding range. If the packing 3 is bonded to the mounting fixture 4 in advance at a factory or similar facility, labor at the construction site can be reduced.

[0033] A brief explanation of the procedure for installing the leak prevention device 1 on an existing flange joint is provided below. First, remove only one of the existing bolts attached to the pair of flanges 11 and 12, clean the flange surface at that location, and then install the fastener 20. Repeat this bolt-to-fastener 20 replacement process for each location. As shown in Figure 14, leave the last location with the bolt removed. This reduces the force of water leaking from the gap 14. In this example, the bolt 21 is inserted from the flange 11 side, but it can be inserted in the opposite direction (see Figures 1-3).

[0034] Next, as shown in Figure 15, multiple segmented pieces 4P are placed over the flanges 11 and 12 from the radially outer side, connected by fasteners 5, and the mounting fixture 4 is fitted onto the flange joint 10. Subsequently, the flange surface where the bolts were removed (shaded area in Figure 15) is cleaned, and the bolts 21 are inserted into the bolt holes and secured with nuts 22. At this time, the fin portion 23f of the sealing material 23 is allowed to enter the bolt holes, thereby improving the sealing performance in those bolt holes. As described above, the fasteners 20 have also been replaced from the existing bolts in the other bolt holes, so the sealing performance is similarly improved.

[0035] By fitting the mounting fixture 4 onto the outside, the packing pieces 3P held by each of the multiple segmented pieces 4P come into contact with the outer circumferential surfaces of the flanges 11 and 12. Consequently, the protrusions 32 abut against the edges of the flanges 11 and 12, closing the opening of the gap 14, and the protrusions 33 and 34 each face the outer circumferential surfaces of the flanges 11 and 12. If the effective length of the packing 3 is the same as or greater than the outer circumferential length of the flanges 11 and 12, the packing 3 is not substantially compressed (the design compression amount is zero) before the fastener 5 is operated to reduce the diameter of the mounting fixture 4.

[0036] Furthermore, by fitting the mounting fixture 4 onto the outside, the first packing end 3X of packing piece 3P is joined to the second packing end 3Y of another packing piece 3P adjacent to that packing piece 3P, thereby forming the packing 3 into an annular shape. As previously described, the pair of side walls 42 protruding circumferentially from the inner circumferential surface 4a of the first connecting end 4X prevents the packing 3 from bending laterally. Since the first packing end 3X and the second packing end 3Y are joined by non-adhesive means, no adhesive is required to form the packing 3 into an annular shape.

[0037] In this embodiment, the outer circumferential surface 3a of the packing 3 and the inner circumferential surface 4a of the mounting fixture 4 are formed flat, but this is not limited to this. For example, interlocking recesses and protrusions may be formed between the outer circumferential surface 3a of the packing 3 and the inner circumferential surface 4a of the mounting fixture 4. With such a configuration, a decrease in sealing performance due to axial misalignment of the packing 3 relative to the mounting fixture 4 can be suppressed. If the recesses and protrusions are composed of a recess formed on the outer circumferential surface 3a of the packing 3 and a protrusion formed on the inner circumferential surface 4a of the mounting fixture 4, the effect of pressing the protrusions toward the flanges 11 and 12 can also be obtained.

[0038] In this embodiment, an example is shown in which both the inclined surface 3Xt and the inclined surface 3Yt are formed flat, but the embodiment is not limited to this. Therefore, for example, interlocking protrusions and recesses may be formed between the inclined surface 3Xt and the inclined surface 3Yt. With such a configuration, a decrease in sealing performance due to misalignment between the first packing end 3X and the second packing end 3Y can be suppressed. In this case, it is preferable to ensure sliding between the inclined surface 3Xt and the inclined surface 3Yt by reducing the size of the protrusions relative to the recesses.

[0039] In this embodiment, an example is shown in which the mounting fixture 4 is divided into two parts, but it is not limited to this, and it may be divided into three or more parts (for example, two to four parts). Preferably, the packing 3 is divided into the same number of parts as the mounting fixture 4, which makes it easier to attach each of the packing pieces 3P constituting the packing 3 to each of the divided pieces 4P constituting the mounting fixture 4. Also, in this embodiment, an example is shown in which the divided parts 4S of the mounting fixture 4 and the divided surfaces 3S of the packing 3 are formed at multiple locations in the circumferential direction, but it is not limited to this, and it is sufficient if they are formed at at least one location in the circumferential direction.

[0040] Those skilled in the art will understand that the embodiments described above are specific examples of the following embodiments.

[0041] [1] The flange joint leakage prevention device of the present disclosure comprises a strip-shaped packing arranged in an annular manner to cover the flange joint of a fluid pipe, and an annular mounting device fitted onto the flange joint via the packing. The packing has a dividing surface formed at least at one location in the circumferential direction, and a first packing end and a second packing end divided by the dividing surface. The mounting device has a dividing portion formed at least at one location in the circumferential direction, and a first connecting end and a second connecting end connected to each other at the dividing portion. The first packing end protrudes circumferentially from the inner circumferential surface of the first connecting end to the inner circumferential surface of the second connecting end. The mounting device has a pair of side walls that face each other with respect to the packing in the axial direction, and the pair of side walls protrude circumferentially from the inner circumferential surface of the first connecting end.

[0042] With this configuration, the first packing end, which protrudes circumferentially from the inner surface of the first connecting end, reaches the inner surface of the second connecting end, so that the portion of the packing including the divided surface is positioned on the inner surface of the second connecting end and held stably, thus improving sealing performance. Furthermore, because the pair of side walls protrude circumferentially from the inner surface of the first connecting end, lateral bending of the first packing end protruding from the inner surface of the first connecting end is suppressed, thus improving workability during installation. Therefore, the device has excellent sealing performance and ease of installation.

[0043] [2] In the leakage prevention device described in [1] above, the first packing end may include a first inclined surface that is inclined with respect to the radial direction and faces radially outward, and the second packing end may include a second inclined surface that is inclined with respect to the radial direction and faces radially inward, overlapping with and in close contact with the first inclined surface. With such a configuration, the first packing end and the second packing end can be joined simply and firmly.

[0044] [3] In the leakage prevention device described in [1] or [2] above, the divided portion may be formed in a comb-like shape, and the first connecting end and the second connecting end may have a complementary shape that fits together. With such a configuration, it is not possible to connect the first connecting end and the second connecting end in the wrong combination, thus improving workability during installation.

[0045] [4] In the leakage prevention device described in [3] above, the first connecting end may have a pair of side teeth extending along the pair of side walls and a center tooth located between the pair of side teeth, and the second connecting end may have a pair of middle teeth positioned between the pair of side teeth and the center tooth. With this configuration, the pair of side walls extending along the side teeth suppress lateral bending of the first packing end, thereby improving workability during installation.

[0046] [5] In any one of the above [1] to [4] leak prevention devices, the second packing end does not have to protrude circumferentially from the inner circumferential surface of the second connecting end. With this configuration, the portion of the packing including the divided surface is properly positioned on the inner circumferential surface of the second connecting end and held stably, thereby improving the sealing performance.

[0047] [6] In any one of the above [1] to [5] leak prevention devices, the second packing end may be bonded to the inner circumferential surface of the second connecting end. This positions the packing relative to the mounting fixture, improving workability during installation.

[0048] [7] In any one of the above [1] to [6] leak prevention devices, a gap along the circumferential direction may be formed between the pair of side walls and the packing. This gap can be used as a margin to allow for axial bulging deformation of the packing.

[0049] [8] In any one of the above [1] to [7] leak prevention devices, the packing may be configured such that a plurality of packing pieces are connected in the circumferential direction, and each of the plurality of packing pieces has a first packing end and a second packing end, and the mounting fixture is configured such that a plurality of segmented pieces are connected in the circumferential direction, and each of the plurality of segmented pieces has the packing piece attached to it. With this configuration, by fitting the mounting fixture made of a plurality of segmented pieces onto the outside, the packing pieces held by each of the segmented pieces are connected in the circumferential direction, and an annular packing covering the flange joint can be formed.

[0050] In this embodiment, a water pipe was used as an example of a fluid pipe, but it is not limited to this and can be applied to fluid pipes used for various liquids other than water, gases, and other fluids.

[0051] While embodiments of the leakage prevention device relating to this disclosure have been described with reference to the drawings, it should be understood that the specific configuration is not limited to these embodiments. The scope of this disclosure is indicated not only by the above-described embodiments but also by the claims, and furthermore, all modifications within the meaning and scope of equivalence to the claims.

[0052] The leakage prevention device relating to this disclosure is not limited in any way to the embodiments described above, nor is it limited to the effects and benefits described above. The leakage prevention device relating to this disclosure can be modified in various ways without departing from its spirit. Furthermore, the various components adopted in the embodiments described above can be arbitrarily combined and adopted. [Explanation of Symbols]

[0053] 1 Leakage prevention device 3. Packing 3a Outer surface 3P packing piece 3S split plane 3X First packing end 3Xt 1st slope 3Y Second packing end 3Yt 2nd slope 4. Mounting hardware 4a Inner surface 4P split piece 4S split section 4X 1st connection end 4Y 2nd connection end 5 Fasteners 10 Flange joint section 11 Flange 12 flanges 30 gaps 42 Side wall 45 side teeth 46 Center teeth 47 Middle teeth P1 Water pipe (an example of a fluid pipe) P2 Water pipe (an example of a fluid pipe)

Claims

1. A flange joint leakage prevention device comprising a strip-shaped packing arranged in an annular shape to cover the flange joint of a fluid pipe, and an annular mounting fixture fitted onto the flange joint via the packing, The packing has a dividing surface formed at least one location in the circumferential direction, and a first packing end and a second packing end separated by the dividing surface. The mounting fixture has a divided portion formed at least one location in the circumferential direction, and a first connecting end and a second connecting end connected to each other at the divided portion. The first packing end protrudes circumferentially from the inner circumferential surface of the first connecting end and reaches the inner circumferential surface of the second connecting end. The mounting fixture has a pair of side walls that face each other in the axial direction, A leakage prevention device for a flange joint, characterized in that the pair of side walls protrude circumferentially from the inner circumferential surface of the first connecting end.

2. The first packing end includes a first inclined surface that is inclined with respect to the radial direction and faces radially outward, The flange joint leakage prevention device according to claim 1, wherein the second packing end includes a second inclined surface that is inclined with respect to the radial direction and faces radially inward, overlapping and in close contact with the first inclined surface.

3. The leakage prevention device for a flange joint according to claim 1, wherein the divided portion is formed in a comb-like shape, and the first connecting end and the second connecting end have complementary shapes that fit together.

4. The first connecting end has a pair of side teeth extending along the pair of side walls and a center tooth located between the pair of side teeth. The leakage prevention device for a flange joint according to claim 3, wherein the second connecting end has a pair of middle teeth positioned between the pair of side teeth and the center tooth.

5. The flange joint leakage prevention device according to claim 1, wherein the second packing end does not protrude circumferentially from the inner circumferential surface of the second connecting end.

6. The flange joint leakage prevention device according to claim 1, wherein the second packing end is bonded to the inner circumferential surface of the second connecting end.

7. Leak prevention device for flange joint portion according to claim 1, wherein a gap along the circumferential direction is formed between the pair of side walls and the packing.

8. The packing is constructed by connecting a plurality of packing pieces in the circumferential direction, and each of the plurality of packing pieces has a first packing end and a second packing end. The flange joint leakage prevention device according to any one of claims 1 to 7, wherein the mounting fixture is constructed by connecting a plurality of segmented pieces in the circumferential direction, and the packing piece is attached to each of the plurality of segmented pieces.

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