JP7064235B2 - Flange type pipe fitting - Google Patents

Description

The present invention is manufactured because the annular gasket is less likely to come into direct contact with the fluid in the pipe due to the metal inner cylinder arranged inside, and the metal inner cylinder that prevents the gasket from being deformed in the radial direction is a simple cylindrical shape. Regarding flange type pipe fittings, which are easy and inexpensive.

In plumbing work such as water supply and air conditioning, a flange type coupling method is used to connect metal pipes in a straight line, and this method is excellent in terms of mechanical strength and piping workability of the connecting part. In the loose flange type pipe joint, the bolt through holes of both flanges can be matched at the time of piping by simply turning one of the flanges, and the metal pipe does not need to be forcibly twisted, so that the piping work is easy. In loose-flange type pipe fittings, loose flanges with multiple bolt through holes are fitted to metal pipes before the pipe end is flanged or the stub end is welded, and the flanges of both metal pipes are fitted. The end faces of the portions are butted against each other via a seat packing or an O-ring, and bolts are passed through the through holes and tightened with nuts.

In conventional flange type pipe fittings, the seat packing or O-ring is made of hard resin or hard rubber, as in the case of Jitsukaihei No. 5-8175 and JP-A-9-163562, which is softer than the metal pipe body. be. For this reason, the tightening force of each bolt must be increased so that the packing or O-ring does not plastically deform when the pressure inside the pipe becomes high or negative, and the bolts are damaged by overtightening. Water leakage occurs, and the loose flange also requires high strength, which increases the overall weight.

On the other hand, the affiliated company of the present applicant has an annular elastic gasket and a metal material arranged on the outer peripheral side of the elastic gasket as a sealing member to be arranged between the flanges in Practical Proposal Registration Nos. 3136954 and 3194436. Proposed a reinforcing ring, the cross section of this elastic gasket is an inverted V-shaped lip. Since the pipe joint disclosed in Utility Model Registration No. 3136954 and No. 3194436 compresses and seals an elastic gasket that is easily deformed by compression, the tightening force of each bolt may be sufficient to withstand the extubation force.

Jitsukaihei No. 5-8175 Japanese Unexamined Patent Publication No. 9-163562 Utility Model Registration No. 3136954 Utility Model Registration No. 3194436 Gazette Utility Model Registration No. 3210602

In the flange type pipe joint disclosed in Practical New Design Registration No. 3136954 and No. 3194436, the tightening force of each bolt may be sufficient to withstand the extubation force, but in this pipe joint, the elastic gasket arranged inside is the fluid in the pipe. Since they are always in direct contact with each other, the rubber gasket is likely to deteriorate over time, and the plasticizer may leak from the gasket to the fluid in the pipe. Applicants used a metal ring with a U-shaped cross section that fits into the inner peripheral side of the annular elastic gasket so that the elastic gasket does not come into direct contact with the fluid in the pipe in Practical New Design Registration No. 3210602. Separation from the elastic gasket delays the progress of deterioration of the gasket over time.

However, in Practical New Plan Registration No. 3210602, since a metal ring having a U-shaped cross section having flanges formed on both sides by flange processing is used, the lower circumferential portion of the elastic gasket fitted in both flange portions comes into contact with the pipe brim portion. Therefore, it is necessary to increase the outer diameter of the elastic gasket in order to obtain a predetermined sealing pressure. Further, the metal ring having a U-shaped cross section manufactured by the brim processing has a considerably higher manufacturing cost than a simple cylindrical ring.

The present invention has been proposed to improve the above-mentioned problems with conventional flange type pipe joints, and by arranging a simple cylindrical metal inner cylinder inside the gasket, the outside of the elastic gasket is provided. It is an object of the present invention to provide a flange type pipe joint which can be reduced in diameter and has less direct contact with the fluid in the pipe. Another object of the present invention is to provide a flange type pipe joint in which the gasket does not deform inward even when the inside of the pipe becomes negative pressure.

In the flange type pipe joint according to the present invention, the end portion of the small diameter pipe is flanged, a packing material is interposed between the flange end faces of both pipes, and then both loose flanges fitted are tightened with bolts. This flange type pipe joint has circular recesses formed on the inner end faces of both loose flanges, and as the packing material, a metal inner cylinder having substantially the same size as the pipe and a diameter smaller than the outer diameter of the flange circular recess. An annular gasket is used on the outer peripheral surface of the metal inner cylinder to be vulched, bonded or baked. This gasket has a rectangular cross section and its width and thickness are slightly larger than the width and thickness of the metal inner cylinder, and the fluid passing through the pipe is less likely to come into contact with the gasket by the metal inner cylinder after the joint is assembled.

In the flange type pipe joint according to the present invention, a circular recess is formed on the inner end faces of both loose flanges, and as a packing material, a tubular metal inner cylinder having substantially the same diameter as a pipe and a larger metal inner cylinder than the metal inner cylinder. An annular gasket having a diameter of the metal outer cylinder and an annular gasket that is vulture-bonded or baked onto the outer peripheral surface of the metal inner cylinder and the inner peripheral surface of the metal outer cylinder may be used. This gasket has a rectangular cross section and its width and thickness are slightly larger than the width and thickness of the metal inner cylinder and the metal outer cylinder. At this time, the metal outer cylinder may be composed of a single body or two narrow rings, and by forming an annular gap between the two narrow rings, a resin ring is formed along the annular gap. It is possible to fit the inner perimeter of the plate.

In the flange type pipe joint according to the present invention, an annular groove is provided on the outer peripheral surface of a gasket or a metal outer cylinder, and the inner peripheral edge of a resin or thin metal plate annular plate is fitted along the annular groove. It is also preferable that the annular plate is provided with circular holes or semi-circular notches for a plurality of bolts. Further, the inner peripheral edge of the metal inner cylinder is projected in the front-rear direction, and the front-rear end surface thereof is in close contact with the bent portion of the pipe brim portion, so that the contact of the fluid passing through the pipe with the gasket is further reduced.

In the flange type pipe joint according to the present invention, by arranging a simple cylindrical metal inner cylinder inside the gasket, the outer diameter of the elastic gasket can be made smaller than before, and the cost of the gasket can be reduced and the weight of the joint can be reduced. It is effective for. Further, the metal inner cylinder used in the present invention is a mere cylindrical ring and can be applied by cutting the connecting pipe into pieces, and the manufacturing cost is higher than that of the metal ring having a U-shaped cross section manufactured by the brim processing. It's very cheap.

In the flange type pipe joint according to the present invention, the gasket is less likely to come into direct contact with the in-pipe fluid due to the metal inner cylinder arranged inside, and the leakage and deterioration of the rubber component of the gasket due to the contact between the in-pipe passing fluid and the gasket are reduced. Can be changed. Since the flange type pipe joint of the present invention is sealed by using a gasket that deforms by compression, the tightening force of each bolt may be sufficient to withstand the pipe ejection force, and even if the inside of the pipe becomes negative pressure, the inside of the metal is arranged inside. No water leakage occurs due to the cylinder.

It is a side view which shows the flange type pipe joint which concerns on this invention. It is an exploded sectional view which shows the arrangement state of the flange type pipe joint of FIG. It is a front view which shows the loose flange used in this invention. It is a front view which shows the packing material which consists of a gasket and a metal inner cylinder used in this invention. It is a partial cross-sectional view which shows the packing material cut along the line AA of FIG. 4 in an enlarged manner. It is a front view which shows the other packing material which attached the annular plate with a hole. It is a partial cross-sectional view which shows the packing material cut along the line BB of FIG. 6 in an enlarged manner. It is a front view which shows another packing material composed of a metal outer cylinder body, a gasket and a metal inner cylinder body. It is a partial cross-sectional view similar to FIG. 7 which shows another packing material in an enlarged manner. It is an enlarged cross-sectional view which shows the deformation example of the metal inner cylinder in the packing material. It is an enlarged cross-sectional view which shows the deformation example of the metal outer cylinder in the packing material.

Explaining the present invention with reference to the drawings, in the flange type pipe joint 1 shown in FIG. 1, the metal pipes 2 and 2 are mainly stainless steel pipes, and the same or different alloy steel pipes, cast iron pipes, cast steel pipes, carbon steel pipes or resin coatings are used. It may be a steel pipe, or a metal pipe having a different inner diameter. The pair of loose flanges 3 and 3 is preferably made of cast iron, cast steel, alloy steel or carbon steel from the viewpoint of cost, stainless steel can also be used, and in the case of cast iron or cast steel, zinc plating or plastic coating is used. May be applied.

The loose flange 3 is a donut-shaped plane as illustrated in FIG. 3, and is usually provided with a plurality of circular or irregular mounting holes 5 at equal intervals in the circumferential direction. The contour of the flange 3 is recessed except for the portion 6 where the plurality of mounting holes 5 are present to reduce the size and weight, and 3 to 6 mounting holes are arranged at equal intervals in the circumferential direction. A circular recess 8 is provided on the inner surface of the loose flange 3 concentrically with the inner diameter, that is, the through hole 7, and the peripheral wall of the recess does not come into contact with the peripheral wall of the mounting hole 5. Since the packing material 16 (FIG. 4) may have a smaller diameter than the conventional loose flange 3, the planar shape thereof is considerably smaller and thinner than the conventional product shown by the alternate long and short dash line in FIG. 3, and as a result, the loose flange 3 is cheaper. And it becomes lighter. The loose flange 3 may be formed in a donut shape as shown in the figure or in two halves.

As shown in FIG. 2, in the loose flange 3, the diameter of the through hole 7 may be substantially equal to or slightly larger than the outer diameter of the metal pipe 2 to be connected. The diameter of the circular recess 8 is set to be substantially equal to or slightly larger than the outer diameter of the brim portion 10 at the end of the pipe and the outer diameter of the gasket 12. Further, the depth of the circular recess 8 is set to be substantially equal to or smaller than the added value of the thickness of the brim portion 10 at the end of the pipe and half the thickness of the metal inner cylinder 14 (FIG. 2). , See FIG. 10).

The annular gasket 12 (FIG. 4) constitutes the packing material 16 together with the annular metal inner cylinder 14. As shown in FIGS. 2 and 5, the gasket 12 has a rectangular cross section or a chamfered rectangle and has a shape close to a square. Normally, when integrated with the metal inner cylinder 14 by injection molding or the like, the inner circumference of the gasket 12 is formed. The surface becomes flat. The gasket 12 is made of highly elastic rubber or plastic, and for example, ethylene propylene diene rubber (EPDM), ethylene propylene rubber (EPM), polypropylene, polyester, polyamide, polyacetal resin, or the like is used.

As shown in FIGS. 2 and 5, the metal inner cylinder 14 (FIG. 4) is merely a cylinder, and is fitted into the inner peripheral surface of the gasket 12 to be integrated. The metal inner cylinder 14 is made of stainless steel, cast steel, carbon steel, or the like, and if it is made of cast steel or carbon steel, it may be subjected to anticorrosion processing such as zinc plating or resin coating. The metal inner cylinder 14 has a wall thickness of about 0.7 to 3.0 mm and generally has the same inner and outer diameters as the metal pipe 2. For example, the metal pipe 2 is cut into short cylinders and used as it is. You may. When the metal inner cylinder 14 is fitted into the inner circumference of the gasket and vulcanized and bonded or baked in order to be integrated with the gasket 12, a strong adhesive interface is obtained. Therefore, when the metal inner cylinder 14 and the gasket 12 are used. It will not peel off.

The width and thickness of the gasket 12 is slightly thicker than the metal inner cylinder 14 as shown in FIG. 5 when not compressed, and becomes almost the same thickness as the metal inner cylinder 14 after the joint is assembled (one-dot chain line in FIG. 5). reference). When the loose flanges 3 and 3 are tightened, the thickness of the gasket 12 is usually compressed to 85 to 95%, and the tightening makes the surfaces of the gasket 12 and the metal inner cylinder 14 substantially flush with each other. Further, the compression thickness of the gasket 12 is usually slightly larger than the addition depth of the circular recesses 8 and 8 of the loose flanges 3 and 3 when the wall thickness of the tube brim portions 10 and 10 is added, and the loose flanges 3 and 3 are formed. When tightened, a minute gap is generated between the end faces of both flanges as shown in FIG. 1, and a cover (not shown) may be further covered to hide this gap.

In the flange type pipe joint 1, usually, after the loose flange 3 is fitted to the metal pipes 2 and 2, the end portion of the pipe is bulged. In this brim processing, for example, at a piping site or a pipe processing factory, a brim portion 10 is formed at a right angle outward in the radial direction by a known brim processing machine, and then the other end portion of the pipe is also bridged in the same manner. Process. After that, the packing material 16 is interposed between the end faces of the brim portion 10 of the metal pipe 2, and then the flanges 3 and 3 are joined and tightened with a plurality of sets of bolts 18 and nuts 20.

In the flange type pipe joint 1, when the loose flanges 3 and 3 are tightened with the bolt 18 and the nut 20, the gasket 12 is appropriately compressed and the front and rear end faces of the metal inner cylinder 14 are not deformed. It is in close contact with the end face of the pipe brim portion 10. As a result, the metal inner cylinder 14 comes into direct contact with the passing fluid of the metal pipes 2 and 2, and the gasket 12 made of rubber or the like hardly comes into contact with the passing fluid, so that the progress of deterioration of the gasket over time is slowed down. , It is possible to prevent the rubber plasticizer from leaking from the gasket to the passing fluid. On the other hand, even when the inside of the pipe becomes negative pressure, since the metal inner cylinder 14 is arranged on the inner peripheral side of the gasket, the inward deformation of the gasket 12 can be prevented in advance, and water leakage due to the deformation of the gasket 12 can be prevented. No accidents occur.

In the packing material 22 shown in FIG. 6, an annular plate 24 is attached to the outer peripheral surface of the gasket 12, and a plurality of circular holes 26 for bolts are provided in the plate at equal intervals in the circumferential direction. The annulus plate 24 is made of a donut-shaped thin metal plate, a resin sheet, or the like, and has a smaller outer diameter than usual in order to reduce the weight. You may. The flange 3 (FIG. 3) can also have the same appearance as that of FIG. 6 for weight reduction so as to match the annular plate 24.

As shown in FIG. 7, the annular plate 24 is fixed by fitting the inner peripheral edge into the annular groove 28 provided on the outer peripheral surface of the gasket. When the packing material 22 is provided with the annular plate 24 and is temporarily fixed by passing bolts 18 through the circular holes 26, the packing material 22 does not shift in position when the loose flanges 3 and 3 are tightened, and the connecting portion of the pipe is formed. The packing material 22 can be easily positioned even if it is horizontal. Since the annular plate 24 is only used for holding the packing material 22 until the loose flanges 3 and 3 are tightened, no particular strength is required.

The packing material 30 shown in FIG. 8 has a tubular metal inner cylinder 14, an annular gasket 34, and a metal outer cylinder 32 having a diameter larger than that of the metal inner cylinder 14. Similar to the gasket 16 shown in FIG. 5, the gasket 34 has a substantially rectangular cross section, and its width and thickness are slightly larger than the width and thickness of the metal inner cylinder 14 and the metal outer cylinder 32. Vulcanization adhesion or baking is performed on the outer peripheral surface of the cylinder 14 and the inner peripheral surface of the metal outer cylinder 32.

The metal outer cylinder 32 may be made of the same or similar material as the metal inner cylinder 14, and has the same width and thickness as the metal inner cylinder 14. The metal outer cylinder 32 may be merely a cylindrical shape, and after assembling the joint, the front and rear end faces of the metal outer cylinder 32 and the metal inner cylinder 14 are in close contact with the pipe brim, and the fluid passing through the pipe is the metal inner cylinder 14. Makes almost no contact with the gasket. When assembling the joint, the metal outer cylinder 32 effectively prevents the gasket 34 from expanding outward, so that the gasket can be tightened at a higher pressure, and the pressure resistance of the flange type pipe joint is further increased.

In the packing material 30 shown in FIG. 8, the thin annular plate 24 shown in FIG. 6 can be attached. In FIG. 9, the metal outer cylinder 32 is composed of two parallel narrow rings 36, 36, and forms a narrow annular gap 38 between the two cylinders. The annulus plate 24 may be fixed by fitting the inner peripheral edge into the gap 38. Further, in FIG. 10, an annular groove 42 may be provided on the outer periphery of the metal outer cylinder 40, and the inner peripheral edge of the annular plate 24 may be fitted and fixed in the annular groove.

In FIG. 11, the inner peripheral edge of the metal inner cylinder 42 projects in the front-rear direction, and the inner peripheral edge thereof is wider than the outer peripheral edge. If possible, it is preferable that the front-rear end surface 44 is not a mere inclined surface, but the cross section is cut into a curved shape so as to be in close contact with the bent portion 46 of the pipe brim portion 10. As a result, when assembling the joint, the front and rear end faces 44 of the metal inner cylinder 42 can be brought closer to the pipe brim portion 10, and the contact of the fluid passing through the pipe with the gasket is further reduced. In order to cut the front-rear end surface 44 into a curved shape, it is necessary that the radius of curvature of the bent portion is large to some extent.

Since the inner peripheral edge of the metal inner cylinder 42 of the packing material 48 projects in the front-rear direction, the packing material 48 can be accurately positioned by simply fitting the packing material into the pipe brim portion 10. Therefore, even if the annular plate 24 for positioning is omitted, if an adhesive is applied to one end surface of the gasket 34, it can be easily temporarily fixed with the adhesive when it is fitted to the pipe brim portion 10. Further, since the pipe 2 is usually a ferrite-based stainless steel pipe and is attached to a magnet, if the metal outer cylinder 40 is magnetized or the gasket 34 is made of a rubber magnet, the packing material 48 is temporarily fixed by simply fitting the packing material 48 into the pipe brim portion 10. It can be positioned easily.

In the packing material 50 shown in FIG. 11, the inner peripheral edge of the metal inner cylinder 42 protrudes in the front-rear direction, and the width of the metal outer cylinder 52 is substantially equal to the outer dimensions between the pipe brim portions 10 and 10 when the joint is tightened. Moreover, the inner diameter of the metal outer cylinder is determined to be substantially equal to the outer diameter of the pipe brim portion 10. At this time, if the front and rear inner peripheral surfaces of the metal outer cylinder 52 or the outer peripheral surface of the brim portion 10 are cut in a slightly tapered shape in the axial direction, the packing material 50 is strongly pushed toward the brim portion 10 or lightly. The packing material can be temporarily fixed by fitting it into the pipe brim portion 10 just by driving it in, and the annular plate 24 for positioning and the adhesive can be omitted. Further, the packing material 50 can be temporarily fixed only by caulking the metal outer cylinder 52 and the brim portion 10.

Next, the present invention will be described based on examples, but the present invention is not limited to the examples. In the flange type pipe joint 1 shown in FIG. 1, the loose flanges 3 and 3 made of cast steel are substantially donut-shaped planes having a central through hole 7 as shown in FIG. 3, and the diameter of the through hole is 50.4 mm. be. The loose flange 3 is provided with three bolt mounting holes 5 outside the circular recess 8 having a diameter of 62.9 mm at equal intervals in the circumferential direction.

The metal pipes 2 and 2 have a nominal diameter of 40 A, an inner diameter of 46.2 mm, an outer diameter of 48.6 mm, and a wall thickness of 1.2 mm. The metal pipes 2 and 2 are stainless steel pipes made of the same ferritic stainless steel. A loose flange 3 is fitted to the metal pipe 2 before the end of the pipe is flanged. The outer diameter of the brim portion 10 is 61.9 mm.

For the loose flange 3, the diameter of the central through hole 7 is slightly larger than the outer diameter of the metal pipe 2 to be connected. The diameter of the circular recess 8 is 62.9 mm, which is about 0.5 mm larger in radius than the outer diameter of the brim 10 at the end of the pipe. Further, the depth of the circular recess 8 is about 4 mm, which is slightly smaller than the sum of the wall thickness of the brim portion 10 at the end of the pipe of 1.2 mm and half the thickness of the gasket 12.

Regarding the packing material 16, the metal inner cylinder 14 is made of ferritic stainless steel similar to the metal pipe 2, and is simply a cylinder having a width thickness of 6 mm, an inner diameter of 46.2 mm, and an outer diameter of 48.6 mm. The gasket 12 is molded by injection molding and baked onto the outer peripheral surface of the metal inner cylinder 14. The gasket 12 is made of highly elastic EPDM having a wall thickness of about 7 mm, an inner diameter of 46.2 mm, and an outer diameter of 61.9 mm in order to obtain a desired tightening force, and has a chamfered rectangular cross section as shown in FIG. The shape is close to a square.

Both metal pipes 2 and 2 are arranged to face each other with the metal inner cylinder 14 and the packing material 16 having the gasket 12 interposed therebetween, and then the end faces of the loose flanges 3 and 3 are abutted against each other. At this time, the brim portions 10, 10 and the gasket 12 are housed in the circular recesses 8 and 8 of both loose flanges 3, and after aligning the loose flanges 3 and 3, three humped bolts 18 are attached to the nut 20. Tighten and assemble.

In the flange type pipe joint 1, the gasket 12 is compressed by the loose flanges 3 and 3, and both end faces of the metal inner cylinder 14 are in close contact with the side surfaces of the brim portions 10 and 10, so that the tightening force by the three humped bolts 18 is applied. Should be sufficient to withstand the extubation force. Three tightening bolts 18 is sufficient, and even if the area of the contact surface of the brim portion 10 of the metal pipe 2 in the gasket 12 is almost the same as the conventional one, the flange 3 having the three bolt mounting holes 5 is The outer diameter is smaller than that of the conventional loose flange, and referring to the alternate long and short dash line in FIG. 3, the whole is compact and space saving.

In the flange type pipe joint, the loose flange made of cast steel is a substantially donut-shaped plane having a central through hole as shown in FIG. 3, and the diameter of the through hole is 62.7 mm. The loose flange is provided with three bolt mounting holes at equal intervals in the circumferential direction on the outside of the circular recess 8 having a diameter of 74.8 mm. The metal pipe has a nominal diameter of 50 A, an inner diameter of 58.1 mm, an outer diameter of 60.5 mm, and a wall thickness of 1.2 mm. A loose flange 3 is fitted to the metal pipe before the end of the pipe is flanged. The outer diameter of the brim portion 10 is 73.8 mm.

In this loose flange, the diameter of the central through hole is slightly larger than the outer diameter of the metal pipe 2 to be connected, and the diameter of the circular recess 8 is 74.8 mm, which is larger than the outer diameter of the brim at the end of the pipe. .. Further, the depth of the circular recess 8 is about 5 mm.

Regarding the packing material 30 (FIG. 8), the metal inner cylinder 14 and the metal outer cylinder 32 are made of ferritic stainless steel similar to the metal pipe, and both have a width thickness of 6 mm and a wall thickness of 1.2 mm and are made of metal. The inner cylinder 14 has an inner diameter of 58.1 mm, and the metal outer cylinder 32 has an outer diameter of 73.8 mm, which is simply a cylindrical shape. The gasket 34 is molded by injection molding and baked onto the outer peripheral surface of the metal inner cylinder 14 and the inner peripheral surface of the metal outer cylinder 32. The gasket 34 is made of highly elastic EPDM having a wall thickness of about 7 mm in order to obtain a desired tightening force.

In this flange type pipe joint, even if the gasket 34 is compressed by the loose flanges 3 and 3, the metal inner cylinder 14 and the metal outer cylinder 32 do not deform in the radial direction, and the metal inner cylinder 14 and the metal outer cylinder 32 do not deform. Both end faces are in close contact with the side surfaces of the flange portions 10 and 10 (see FIG. 10). Therefore, the flange type pipe joint has a higher pressure resistance than the flange type pipe joint 1 of the first embodiment. This flange type pipe joint is mainly used in places where the connection part of the pipe is vertical.

In the flange type pipe joint of the second embodiment, as shown in FIG. 10, an annular groove 42 is provided on the outer periphery of the metal outer cylinder 40, and the inner peripheral edge of the annular plate 24 (see FIG. 6) is fitted into the annular groove 42. Fix with. When the packing material 48 is provided with the annular plate 24 and temporarily fixed by passing the bolt 18 through the circular hole 26, the packing material 48 does not shift in position when the loose flanges 3 and 3 are tightened, and the connecting portion of the pipe is formed. It can be easily positioned even if it is horizontal.

In the packing material shown in FIG. 10, the metal outer cylinder 40 is merely a cylinder, and it is not necessary to provide an annular groove 42 on the outer periphery thereof. On the other hand, the inner peripheral edge of the metal inner cylinder 42 protrudes in the front-rear direction, the inner peripheral edge thereof becomes wider than the outer peripheral edge, and the metal inner peripheral edge is cut with a lathe so that its cross section becomes curved. When assembling the joint, the packing allows the front and rear end faces 44 of the metal inner cylinder 42 to be in close contact with the pipe brim portion 10, and the contact of the fluid passing through the pipe with the gasket is further reduced.

Since the inner peripheral edge of the metal inner cylinder 42 protrudes in the front-rear direction of this packing material, accurate positioning can be performed simply by fitting the packing material into the pipe brim portion 10. Therefore, if an adhesive is applied to one end surface of the gasket 34, even if the annular plate 24 for positioning is omitted, it can be easily temporarily fixed by the adhesive when it is fitted to the pipe brim portion 10. Therefore, the packing material 48 can be temporarily fixed independently without passing through the bolt 18, the packing material does not shift in position when the loose flanges 3 and 3 are tightened, and the connection portion of the pipe is horizontal or vertical. It can be connected easily and accurately regardless.

1 Flange type pipe fitting 2, 2 Metal pipe 3 Loose flange 5 Bolt mounting hole 8 Circular dent 10 Brim 12 Gasket 14 Metal inner cylinder 16 Packing material 32 Metal outer cylinder

Claims (5)

It is a pipe joint in which the end of the pipe is flared, a packing material is interposed between the end faces of the brim of both pipes, and then both loose flanges fitted are tightened with bolts. As the packing material, a metal inner cylinder having a wall thickness of 0.7 to 3.0 mm, which is a mere cylindrical body, and an outer circumference of the metal inner cylinder having a diameter smaller than the outer peripheral diameter of the flange circular recess. An annular gasket that is vulture-bonded or baked is used on the surface, and the metal inner cylinder is used by cutting a part of the metal pipe to be connected into a short cylinder, and the gasket has a rectangular cross section. A flange type pipe joint whose width is slightly larger than the width and thickness of the metal inner cylinder, and the fluid passing through the pipe is less likely to come into contact with the gasket due to the metal inner cylinder after the joint is assembled. It is a pipe joint in which the end of the pipe is flared, a packing material is interposed between the end faces of the brim of both pipes, and then both loose flanges fitted are tightened with bolts. As the packing material , a metal inner cylinder which is a simple cylinder having a wall thickness of 0.7 to 3.0 mm, a metal outer cylinder having a diameter larger than that of the metal inner cylinder, and a metal inner cylinder. Using an annular gasket that is vulture-bonded or baked to the outer peripheral surface of the cylinder and the inner peripheral surface of the metal outer cylinder, the metal inner cylinder cuts a part of the metal pipe to be connected into a short cylinder. In use, the gasket has a rectangular cross section and its width is slightly larger than the width and thickness of the metal inner cylinder and the metal outer cylinder, and after assembling the joint, the fluid passing through the pipe is supplied by the metal inner cylinder. Flange type pipe joints that rarely come into contact with gaskets. The metal outer cylinder is composed of two narrow rings, and an annular gap is formed between the two narrow rings so that the inner peripheral edge of the resin annular plate is fitted along the annular gap. The pipe joint according to claim 2, wherein the annular plate is provided with circular holes or semicircular notches for a plurality of bolts. An annular groove is provided on the outer peripheral surface of the gasket, and the inner peripheral edge of a resin or thin metal plate annular plate is fitted along the annular groove, and the annular plate has circular holes for a plurality of bolts. Or the pipe joint according to claim 1 or 2, which is provided with a semicircular notch. Claim 1 or 2 that the inner peripheral edge of the metal inner cylinder is projected in the front-rear direction, and the front-rear end face thereof is in close contact with the bent portion of the pipe brim to further reduce the contact of the fluid passing through the pipe with the gasket. The described pipe fitting.

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