JP3136954U - Loose flange fitting - Google Patents

Abstract

A loose flange type in which the sealing side surface and outer peripheral surface of an elastic gasket are pressed toward a reinforcing ring to increase the sealing force as the inner pressure of the tube increases, and the tightening force by each bolt can withstand the tube pulling force. Provide pipe fittings.
An annular elastic gasket 10 and a metal reinforcing ring 8 disposed on the outer peripheral side of the gasket are used. The elastic gasket has a lip shape having a substantially inverted V-shaped cross section, and the reinforcing ring is provided on the reinforcing ring. At least one extension projecting outward in the radial direction, and a bolt through hole is provided in the extension.
[Selection] Figure 1

Description

  The present invention relates to a loose flange type pipe joint in which the seal side and outer peripheral face of an elastic gasket are pressed toward a reinforcing ring to increase the sealing force as the pipe internal pressure increases.

  In plumbing work such as water supply and air conditioning, a piping diagram is created in advance, and metal pipes are processed at the factory according to this piping diagram. From the viewpoint of piping workability, the flange type coupling method is preferable. In fixed flange type pipe joints, since the flange is welded to the pipe end, it is not easy to match the bolt through hole of the flange during piping, and even if the metal pipe is forcibly twisted, the bolt hole must be matched. In other words, this tends to cause delays in piping work and damage to pipes.

  Loose flange-type pipe joints are disclosed in, for example, FIG. 7 attached to Japanese Patent Laid-Open No. 9-14545, and it is easier to match bolt holes than fixed flange-type pipe joints. As illustrated in FIG. 7, the loose flange 100 is formed separately from the metal pipes 102, 102, and is welded to the metal pipe 102 before welding the stub end to the pipe end or swaging the pipe end. Fit each one. Both flanges 100 are provided with a plurality of bolt through holes 104 at equal intervals in the circumferential direction. The surfaces of the brim portions 106 of both pipes are abutted through the sheet packing 108, and bolts 110 are tightened with nuts through the through holes 104. Since the sheet packing 108 is generally made of hard resin or hard rubber and is softer than the metal pipe body, the sheet packing 108 has a collar as shown in FIG. 7 so as not to be plastically deformed when the inside of the pipe becomes high pressure or negative pressure. It is necessary to set the surface area to be approximately the same size as the portion 106 and prevent deformation by frictional resistance.

  In the conventional loose flange type pipe joint, in order to secure a high sealing force between the pipes 102 and 102 by the interposed sheet packing 108, the tightening force by each bolt 110 must be considerably increased. In some cases, the sheet packing 108 may break and water leakage may occur. In addition, since a strong tightening force is required, the loose flange 100 also needs to have high strength, which increases its weight and increases the outer diameter of the flange, making it difficult to secure a work space at the work site.

In a loose flange type pipe joint, in order to obtain a high sealing force between both pipes, the use of an O-ring together with a seat packing is known from Japanese Patent Laid-Open No. 9-14545 or Japanese Utility Model Laid-Open No. 4-133430. In Japanese Patent Laid-Open No. 9-14545, in FIG. 4, an O-ring is disposed on the inner peripheral surface side of the packing, and the outer diameter of the packing is substantially the same as the outer diameter of the loose flange. On the other hand, in Japanese Utility Model Laid-Open No. 4-133430, an O-ring is arranged on the inner peripheral surface side of the outer ring corresponding to the seat packing, and the outer diameter of the outer ring is larger than the outer diameter of the pipe collar portion.
Japanese Patent Laid-Open No. 9-14545 Japanese Utility Model Publication No. 4-133430

  When an O-ring is used in combination with a loose flange type pipe joint as in Japanese Patent Application Laid-Open No. 9-14545 and Japanese Utility Model Laid-Open No. 4-133430, the sealing force between both pipes can be relatively high, but the bolt can be prevented from being overtightened. The sealing force is not increased, and a strong tightening force is required as in the conventional case. Since this O-ring is usually an elastic material having a circular cross section, it tends to be deformed inward when a negative pressure is applied to the inside of the pipe, resulting in a problem that the sealing force between the two pipes is somewhat reduced.

  Further, in JP-A-9-14545, the outer diameter of the seat packing is almost the same as the outer diameter of the loose flange, and the loose flange becomes heavier depending on the size of the flange, and the outer diameter of the flange is also large. It is difficult to secure a work space at the work site. On the other hand, in Japanese Utility Model Laid-Open No. 4-133430, the material of the outer ring corresponding to the packing is not clear, but the outer diameter of the outer ring is larger than the outer diameter of the pipe collar and the axial width is considerably larger. In addition to cost and labor during machining, positioning of the outer ring is difficult during installation.

  The present invention has been proposed in order to improve the above-mentioned problems associated with conventional loose flange type pipe joints. A loose flange type pipe joint that increases the sealing force by an elastic gasket as the pipe internal pressure increases. It is intended to provide. Another object of the present invention is that a strong tightening force by bolts is not required, so the number of tightening bolts is almost halved compared to the conventional one, the loose flange is thin and the flange outer diameter is relatively small, and the work space is reduced at the work site. It is to provide a loose flange type pipe joint that is easy to secure. Another object of the present invention is to provide a loose flange type pipe joint in which the elastic gasket is not deformed inward even when the pressure inside the pipe becomes negative, and the sealing force between the pipes does not decrease. It is.

  In the loose flange type pipe joint according to the present invention, pipe ends are welded or stub ends are welded, a sealing member is interposed between the flange end faces of both pipes, and then both loose flanges fitted are connected. Combine and tighten. The loose flange type pipe joint according to the present invention uses an annular elastic gasket and a metal reinforcing ring disposed on the outer peripheral side of the gasket as a sealing member, and the elastic gasket has a substantially inverted V-shaped cross section. The reinforcing ring is formed with at least one extending portion projecting radially outward, and a bolt through hole is provided in the extending portion.

  In the loose flange type pipe joint according to the present invention, it is preferable that the reinforcing ring is made of stainless steel, carbon steel or a casting, and the elastic gasket is made of rubber or plastic. Preferably, the reinforcing ring has a rectangular cross section, and its axial width is thinner than the axial width of the elastic gasket by the compression of the gasket, and is 50 to 95% of the axial width of the elastic gasket. The reinforcing ring has a thickness that is at least as strong as the pipe thickness of the connection pipe, and its outer diameter is about the same as the collar diameter of the connection pipe.

  The loose flange type pipe joint of the present invention uses an annular elastic gasket and a metal reinforcing ring arranged on the outer peripheral side of the gasket as a sealing member, and a metal support ring on the inner peripheral side of the elastic gasket. By disposing, the support ring may prevent inward deformation of the elastic gasket when the inside of the pipe becomes negative pressure. The support ring is preferably made of stainless steel, carbon steel or casting, and the support ring preferably has a circular or rectangular cross section.

  The present invention will be described with reference to the drawings. In the loose flange type pipe joint 1 shown in FIG. 1, the connection pipes 3 and 3 are the same or similar metal pipes or plastic pipes, and pipes or metal pipes and plastic pipes having different inner diameters. It may be used. Although various metals can be used for the pipe 3 and the flange 2, the pipe 3 is preferably made of stainless steel, and the flange 2 is made of stainless steel, carbon steel or casting. In the case of carbon steel or casting, galvanization or plastic coating may be applied. The flange 2 is generally a loose flange having a circular plane, but it may be a square or elliptical plane.

  The elastic gasket 10 is made of elastic rubber or plastic. For example, polypropylene, polyester, polyamide, polyethylene, polyacetal or the like is used, and when used for piping in a chemical plant or the like, its peripheral surface has corrosion resistance. It is preferable to coat a thin film. The outer diameter of the elastic gasket 10 may be approximately equal to the inner diameter of the reinforcing ring 8. The elastic gasket 10 is usually installed separately from the reinforcing ring 8 but may be integrated by inserting the reinforcing ring 8 on the outer peripheral surface thereof. When the elastic gasket 10 is compressed and deformed and the thickness is reduced to 50 to 95%, it matches the thickness of the reinforcing ring 8.

  The elastic gasket 10 has a recess 18 (FIG. 4) in the lower central portion of its transverse cross section so that it can be easily crimped toward the reinforcing ring 8. The elastic gasket 10 has a substantially inverted V-shaped cross section, and may have an inverted V shape as a whole even if it has an inverted V shape only on the inner peripheral surface. Includes a circle. In the cross section of the gasket 10, the lip portions 23, 23 extending obliquely downward project out from the side surfaces 20, 20 of the gasket 10, so that the side surfaces 20, 20 of the gasket 10 are piped. It is easy to adhere to the surface of the collar portion of 3.

  The reinforcing ring 8 is made of an annular thin stainless steel, carbon steel or casting. The reinforcing ring 8 is formed with at least one positioning extension 24 (FIG. 3) protruding outward in the radial direction, and a bolt through hole 12 is provided in the extension. As shown in FIG. 3, the reinforcing ring 8 usually has two extension portions 24, 24 protruding in opposite directions with respect to the diametrical direction, and the bolt through holes 12 may be provided in the extension portions.

  In the reinforcing ring 8, the number of the extension portions 24 can be arbitrarily determined according to the number and positions of the bolt holes 5 (FIG. 2) of the flange 2. For example, four extension portions are arranged at intervals of 90 °. It is also possible to arrange them in three at intervals of 120 °. Further, if this extension is cut out and formed into a hook shape, the reinforcing ring 8 and the elastic gasket 10 can be attached to both flanges 2 even after being temporarily fixed with bolts 14. Is included.

  When cutting the reinforcing ring 8 from the metal sheet, if the reinforcing ring 8 is arranged obliquely, even if the reinforcing ring 8 is provided with the extension portions 24, 24 protruding outward in the radial direction, the metal sheet is almost superfluous. Never used. If the extensions 24, 24 are slightly modified from the illustration, the amount of metal sheet used can be made exactly the same as that of the conventional circular packing. Since the reinforcing ring 8 is not deformed when tightened with the bolt 14, it is necessary to bring the surface of the flange portion of the pipe 3 into close contact with the surface of the reinforcing ring 8 at this time. Sealed by deformation.

  As shown in FIG. 1, the loose flange type pipe joint 1 is fitted with pipes 3 and 3 with known loose flanges 2, and the ends of the pipes are swung out or the stub ends are welded. In this tapping process, for example, in a pipe processing factory or a piping site, a rib part 7 is formed at a right angle outward in the diameter direction by a known tapping machine, and then the other end of the pipe is tapped out in the same manner. Process. Thereafter, the reinforcing ring 8 and the elastic gasket 10 are interposed between the end faces of the flange portion 7 of the pipe 3, and then both the flanges 2 and 2 are coupled and tightened with the bolt 14 and the nut 16. It is also possible to fit and fix the half-shaped flange after the tapping process.

  At the time of this assembly, for example, it is preferable to fit the flange 2 to the end portion of the pipe 3 and the flange 2 together with a temporary fitting such as a ring band, and then to work out the end portion of the pipe 3. In the piping site, the flanges 7 of the pipes 3 and 3 arranged in the vertical or inclined direction are brought close to each other, and the two flanges 2 and 2 are accurately positioned. At this time, if the temporary fixing metal fitting is disposed immediately behind the flange 2, even if the flange 2 is heavy by tightening the temporary fixing metal fitting, it is possible to prevent the falling or displacement. Further, when the pipes 3 and 3 are horizontally arranged, the reinforcing ring can be accurately positioned by inserting the through hole 12 of the reinforcing ring 8 into the bolt 14 and temporarily fixing it. When this pipe connection work is completed, it is necessary to fix the pipe 3 to a wall surface or the like. At the time of this fixing work, the stopper is moved along the pipe peripheral surface to the mounting position of a fixing bracket (not shown) such as a U-bolt, stops inside the fixing bracket, and then tightens the fixing bracket to tighten the pipe. What is necessary is just to fix 3 and 3.

  In the loose flange type pipe joint, the elastic gasket 10 and the reinforcing ring 8 may be disposed, and a support ring 32 may be further disposed on the inner peripheral side of the elastic gasket 10. The support ring 32 has a circular or rectangular cross section and is made of stainless steel, carbon steel, or a casting. The diameter of the support ring 32 is slightly smaller than the inner diameter of the elastic gasket 10, but larger than the inner diameter of the pipe, and the thickness may be equal to or less than the thickness of the reinforcing ring 8. The support ring 32 prevents the occurrence of a water leakage accident due to the elastic gasket 10 being deformed inward when the inside of the connection pipes 3 and 3 becomes negative pressure.

  Since the loose flange type pipe joint according to the present invention is sealed using an elastic gasket that is relatively easy to compress and deform, the tightening force by each bolt only needs to withstand the tube pulling force and is as strong as a conventional seat packing. There is no need to tighten. In the loose flange type pipe joint of the present invention, an annular reinforcing ring and an elastic gasket are arranged between the flange portions of the connecting pipe, and the higher the internal pressure of the pipe, the stronger the sealing side surface and outer peripheral surface of the elastic gasket of the compression deformation. It is crimped toward the ring, and a high sealing force can be obtained. The loose flange type pipe joint of the present invention does not require a strong tightening force with bolts due to this high sealing force, and the elastic gasket does not break during tightening and use, so there is no problem of water leakage. The loose flange type pipe joint of the present invention does not require a strong tightening force with bolts, so the number of tightening bolts can be almost halved than before, the loose flange can be made thinner and the outer diameter of the flange can be made relatively small, and work can be performed at the work site. Space is easy to secure and pipe connection work becomes easy.

  In the loose flange type pipe joint of the present invention, the support ring is arranged inside the elastic gasket, so that the elastic gasket does not deform inward even when the pressure inside the pipe becomes negative, and the sealing force between the connecting pipes is reduced. Since it does not decrease, a water leakage accident does not occur in any environment. This reinforcing ring is placed between the flange end faces of the connecting pipe when connecting both loose flanges with multiple bolts and nuts, and the flanges are tightened after passing the bolts through the through holes of the extension parts. When tightening, the reinforcing ring and the elastic gasket are not displaced or dropped, their inner diameters are always equal to or larger than those of the connecting pipe, and the carrier fluid can always pass through the fittings smoothly.

  Next, although this invention is demonstrated based on an Example, this invention is not limited to an Example. In the loose flange type pipe joint 1 shown in FIG. 1, the metal loose flanges 2, 2 have a substantially donut shape as shown in FIG. 2, and are formed separately from the connection pipes 3, 3. The pipes 3 and 3 are the same or similar metal pipes or plastic pipes, and metal pipes and plastic pipes can also be used. The flange 2 is provided with four bolt through holes 5 at equal intervals in the circumferential direction, the inner diameter of the flange is substantially equal to the outer diameter of the connection pipe 3, and the diameter of the circle passing below the inner peripheral surface of each through hole 5 is The outer diameter of the flange portion 7 of the pipe 3 and the outer diameter of the reinforcing ring 8 are larger.

  The flanges 2 are respectively fitted to the pipes 3 before the pipe end portions are subjected to a flange processing or a stub end (not shown) is welded to the pipe end portions. Both pipes 3 and 3 abut the surface of the collar portion 7 through the reinforcing ring 8 and the elastic gasket 10, and the nuts 16 are passed through the bolts 14 to the through holes 5 of the flange and the through holes 12 (FIG. 3) of the reinforcing ring 8. Temporarily fix. The reinforcing ring 8 can be accurately positioned by passing the bolts 14 through the two through holes 12 (see FIG. 2), and all the bolts 14 may be tightened with the nuts 16 after the positioning.

  The elastic gasket 10 is made of highly elastic rubber or plastic, and as shown in FIG. 4, the cross section thereof has a substantially inverted V-shaped lip shape. The elastic gasket 10 is determined so that its outer diameter is substantially equal to the inner diameter of the reinforcing ring 8 and its inner diameter is equal to or slightly larger than the inner diameter of the connection pipe 3.

  Since the elastic gasket 10 has a substantially inverted V-shaped cross section, the lower central portion of the cross section is slightly recessed. The recess 18 (FIG. 4) causes the side surface 20, 20 is easily crimped to the surface of the flange portion of the pipe 3 and the outer peripheral surface 22 is pressed toward the reinforcing ring 8. In the cross section of the gasket 10, the lip portions 23, 23 are extended outwardly obliquely downward, and the gap between the tips of both lip portions is larger than the axial width W 2 of the gasket 10. Side surfaces 20 and 20 of the pipe 3 are more closely attached to the surface of the flange portion of the pipe 3.

  The reinforcing ring 8 is annular and made of stainless steel, carbon steel or casting, and in the case of carbon steel or casting, it may be subjected to anticorrosion processing such as galvanization or resin coating. As shown in FIG. 3, the reinforcement ring 8 is provided with extending portions 24, 24 that protrude outward in the opposite direction with respect to the diametrical direction, and the bolt through holes 12 are provided in the extending portions, respectively. The extension 24 has a tongue-like planar shape with a semicircular periphery, and a circular bolt through hole 12 is provided at the center thereof.

  The reinforcing ring 8 has a rectangular cross section as shown in FIG. 4, and its axial width W1 is made thinner than the axial width W2 of the elastic gasket 10 by the amount of compression of the gasket (see FIG. 5). It is set to 50 to 95% of the axial width W2 of the gasket 10. The axial width W1 approaches 50% of the axial width W2 when the elastic gasket 10 is relatively soft, and approaches 95% of the axial width W2 when the elastic gasket 10 is relatively hard. The outer diameter of the reinforcing ring 8 is substantially equal to the outer diameter of the flange portion 7 of the pipe 3, and the inner diameter thereof is larger than the inner diameter of the pipe 3.

  The reinforcing ring 8 preferably has a strength approximately equal to or higher than the strength of the connection pipe 3 with respect to the pipe internal pressure. For this reason, the thickness T1 of the reinforcing ring 8 is determined to be substantially the same as or greater than the thickness T2 of the connection pipe 3.

  In the loose flange type pipe joint 1, the elastic gasket 10 which is relatively easy to compress and deform is brought into close contact as shown in FIG. There is no need to tighten it tightly. For this reason, the number of tightening bolts can be reduced to about half that of the prior art, the area of the contact surface of the flange portions 7 of the connecting pipe 3 may be smaller than the conventional one, and the outer diameter of the collar portion 7 is smaller than the conventional one. it can. Further, the flange 2 having four bolt through holes 5 is smaller in outer diameter and thickness than the conventional flange 100 shown in FIG. 7 even though the inner diameter is substantially equal to the outer diameter of the connection pipe 3. As shown in FIG. 2, it is possible to dent other than the portion 26 where the through-hole 5 exists, and space saving can be achieved by making the whole compact.

  FIG. 6 shows a modification of the present invention. In the loose flange-type pipe joint 30, the elastic gasket 10 and the reinforcing ring 8 are arranged as sealing members, and a support ring 32 having a circular cross section is further arranged on the inner peripheral side of the elastic gasket 10. is doing. The support ring 32 may be made of stainless steel, carbon steel, or casting, and in the case of carbon steel or casting, it is subjected to anticorrosion processing such as galvanization and resin coating. The diameter of the support ring 32 is slightly smaller than the inner diameter of the elastic gasket 10, and the thickness may be equal to or less than the thickness of the reinforcing ring 8.

  The support ring 32 prevents the occurrence of a water leakage accident due to the elastic gasket 10 being deformed inward when the inside of the connection pipes 3 and 3 becomes negative pressure. As shown in FIG. 5, it is preferable that the support ring 32 having a circular cross section is fitted in the recess 18 of the elastic gasket 10 because it is possible to more effectively prevent inward deformation of the gasket.

It is a longitudinal section showing a loose flange type pipe joint concerning the present invention. It is a front view which shows the loose flange used by this invention. It is a front view which shows the reinforcement ring and elastic gasket which are used by this invention. It is an expanded sectional view which shows the cross section of a reinforcement ring and an elastic gasket. It is an expanded sectional view which shows the state by which the elastic gasket of FIG. 4 was fastened, and also shows the support ring in a modification. It is a longitudinal cross-sectional view which shows the modification of this invention. It is a longitudinal cross-sectional view which shows the conventional loose flange type pipe joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Loose flange type pipe joint 2 Loose flange 3, 3 Connection pipe 5 Bolt through-hole 7 Brim part 8 Reinforcement ring 10 Elastic gasket 12 Bolt through-hole 14 Bolt 16 Nut 32 Support ring

Claims (6)

  A pipe joint that pipes the end of the pipe or welds the stub end, interposes a sealing member between the end faces of both pipes, and then joins and tightens both loose flanges. An annular elastic gasket and a metal reinforcing ring disposed on the outer peripheral side of the gasket are used as the members. The elastic gasket has a lip shape having a substantially inverted V-shaped cross section, and the reinforcing ring has a radial direction. A loose flange-type pipe joint in which at least one extension projecting outward is formed and a bolt through hole is formed in the extension.   The pipe joint according to claim 1, wherein the reinforcing ring is made of stainless steel, carbon steel or a casting, and the elastic gasket is made of rubber or plastic.   The pipe joint according to claim 1, wherein the reinforcing ring has a rectangular cross section, and the axial width thereof is thinner than the axial width of the elastic gasket by the compression amount of the gasket, and is 50 to 95% of the axial width of the elastic gasket. .   The pipe joint according to claim 1, wherein the reinforcing ring has a thickness that is at least as strong as the pipe thickness of the connection pipe, and has an outer diameter that is the same as the flange diameter of the connection pipe.   A pipe joint that pipes the end of the pipe or welds the stub end, interposes a sealing member between the end faces of both pipes, and then joins and tightens both loose flanges. As the member, an annular elastic gasket and a metal reinforcing ring arranged on the outer peripheral side of the gasket are used, and a metal support ring is arranged on the inner peripheral side of the elastic gasket, so that the inside of the pipe becomes negative pressure. Loose flange type pipe joint that prevents inward deformation of the elastic gasket with a support ring.   6. The pipe joint according to claim 5, wherein the support ring is made of stainless steel, carbon steel, or a casting, and the support ring has a circular or rectangular cross section.

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