Search

JP-2026075523-A - Flange joint leakage prevention device

JP2026075523AJP 2026075523 AJP2026075523 AJP 2026075523AJP-2026075523-A

Abstract

[Problem] 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. [Selection Diagram] Figure 6

Inventors

  • 伊藤 裕之
  • 西田 昂平

Assignees

  • 株式会社水道技術開発機構

Dates

Publication Date
20260508
Application Date
20241022

Claims (8)

  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 flange joint leakage prevention device 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 leakage prevention device for a flange joint according to claim 1, wherein the second packing end is bonded to the inner circumferential surface of the second connecting end.
  7. The leakage prevention device for a flange joint according to claim 1, wherein a gap is formed in the circumferential direction 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.

Description

This disclosure relates to a device for preventing fluid leakage at flange joints of fluid pipes. At the flange joints of fluid pipes, there is a risk of fluid leakage from the gaps between the flanges due to external forces such as earthquakes or deterioration. To prevent such fluid leakage, or to prevent 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 comprises a band-shaped packing arranged in an annular shape to cover the flange joint, and an annular mounting fixture that is fitted onto the flange joint via the packing. In leak prevention devices, if the portion of the packing including the divided surface is not stably held at the divided portion of the mounting fixture, the sealing performance may be reduced. Therefore, in the leak prevention device described in Patent Document 1, a metal retaining plate spanning the divided portion of the mounting fixture is placed between the packing and the mounting fixture to maintain sealing performance. However, in order to improve the workability when installing the leak prevention device to a flange joint, a structure that can ensure sealing performance without using special additional parts such as a retaining plate is desirable. Japanese Patent Publication No. 2007-100752 Front view showing the leakage prevention device for flange joints.Side view of the leak prevention device in Figure 1.Cross-sectional view along line A-A in Figure 1Cross-sectional view of line B-B in Figure 1Cross-sectional view of packing and mounting fixtureExploded view of the leak prevention devicePerspective view of the first connecting end, seen from the radially inward side.Perspective view of the second connecting end, seen from the radially inward side.Two-view drawing of a packing pieceTwo-view drawing showing the dividing surface of the packing.Two-view drawing showing the dividing surface of the packing.Two-view drawing showing the dividing surface of the packing.A view of the divided section with the packing removed, seen from the radially inner side.A perspective view showing how the leak prevention device is attached to the flange joint.A perspective view showing how the leak prevention device is attached to the flange joint. Embodiments of this disclosure will be described with reference to the drawings. 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 taken along line A-A in Figure 1. Figure 4 is a cross-sectional view taken along line B-B in Figure 1. Figure 5 is a cross-sectional view of the packing 3 and mounting fixture 4 along the line A-A in 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 and 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. 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 this is not limited to this. A gap 14 is formed between the flanges 11 and 12, opening radially outward. The fastener 20 comprises a bolt 21 inserted through the bolt holes of flanges 11 and 12, and a nut 22 screwed onto the bolt 21. The flanges 11 and 12 are clamped between the head of the bolt 21 and the nut 22. The fastener 20 further includes a sealing material 23 that seals the gap in the bolt hole, a metal watertight ring 24 that covers the sealing material 23, and a spacer 25 used for adjusting the position of the bolt 21 and nut 22. Each sealing material 23 has a fin portion 23f (see Figure 15) that fits into the bolt hole. The nut 22 may be changed to a cap nut, or some or all of the spacer 25 may be omitted. In the flange joint 10, if the flanges 11 and 12 separate from each other due to external forces such as earthquakes or deterioration, fluid may leak (i.e., water leakage) from the gap 14. Therefore, to prevent water leakage from the gap 14, or to prevent water leakage that has already occurred, a leakage prevention device 1 is attached to the flange joint 10. If the f