JP2016089970A - Loose flange type pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loose flange type pipe joint which has a packing member comprising a reinforcement ring made of metal and elastic gaskets made of rubber and prevents the elastic gaskets made of the rubber or the like from directly contacting with a fluid passing through a pipe with the reinforcement ring made of the metal.SOLUTION: In a loose flange type pipe joint, a packing member includes: a pair of annular elastic gaskets; a metal reinforcement ring holding the gaskets; and an outer frame body with bolt holes. Annular grooves are provided on side surfaces of the reinforcement ring, and the elastic gaskets respectively fit in the annular grooves.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a loose flange type pipe joint having a packing member constituted by a metal reinforcing ring and an elastic gasket made of rubber or the like, and the elastic gasket made of rubber or the like directly with the passing liquid in the pipe by the metal reinforcing ring. The present invention relates to a loose flange type pipe joint that does not contact.

  In plumbing work such as water supply and air conditioning, various pipe joints are used to connect metal pipes in a straight line. At this time, the flange type coupling method is preferable in terms of mechanical strength of the connecting portion and piping workability of the large-diameter pipe. Loose flange type pipe joints allow the bolt through-holes of the flange to coincide with each other during piping simply by turning the flange, and it is not necessary to forcibly twist the metal pipe, so that the piping work can be carried out quickly. Many loose flange type pipe joints are disclosed in Japanese Patent Application Laid-Open Nos. 9-14545 and 4-133430.

  Referring to FIG. 1 for a conventional loose flange type pipe joint, the loose flange 3 is formed separately from the metal connecting pipes 4 and 4, and a stub end is welded to the pipe end or the pipe end is swung out. Before processing, each connection pipe 4 is fitted. Both loose flanges 3 are provided with a plurality of bolt through holes 5 at equal intervals in the circumferential direction. The surfaces of the flange portions 7 of both pipes are abutted through disc-shaped sheet packing (not shown), and bolts 24 are passed through the through holes 5 and tightened with nuts 26. Generally, a hard resin or hard rubber is used for the sheet packing.

  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 disk-shaped sheet packing is known from Japanese Patent Laid-Open No. 9-14545 or Japanese Utility Model Laid-Open No. 4-133430. It is. In Japanese Patent Laid-Open No. 9-14545, in FIG. 4, an O-ring is arranged 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, in FIG. 2, 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. .

On the other hand, the present applicant has already proposed an annular elastic gasket and a metal reinforcing ring arranged on the outer peripheral side of the gasket as a packing member arranged between both flanges in Utility Model Registration No. 3136954. The cross section of the elastic gasket is an inverted V-shaped lip. Since the pipe joint disclosed in Utility Model Registration No. 3136954 is sealed using an elastic gasket that is easily compressed and deformed, the tightening force by each bolt only needs to withstand the tube pulling force. There is no need to tighten it strongly like Kaihei 4-133430. In this loose flange type pipe joint, the higher the internal pressure of the pipe, the higher the sealing pressure and the outer peripheral surface of the compression-deformed elastic gasket are pressure-bonded toward the reinforcing ring.
Japanese Patent Laid-Open No. 9-14545 Japanese Utility Model Publication No. 4-133430 Utility Model Registration No. 3136954

  When an O-ring is used in combination with a loose flange type pipe joint as in JP-A-9-14545 and Japanese Utility Model Laid-Open No. 4-133430, the O-ring is easily deformed inward when the inside of the pipe becomes negative pressure. The problem arises that the sealing force between the two pipes is reduced. 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 outer diameter of the flange is also large, so 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.

  In the pipe joint disclosed in Utility Model Registration No. 3136954, a metal reinforcing ring is disposed on the outer peripheral side of the gasket, and the reinforcing ring is a thin metal member such as an annular stainless steel. The reinforcing ring is formed with at least one positioning extension projecting outward in the radial direction, and a bolt hole is provided in the extension. When the reinforcing ring is manufactured by punching from a thin metal sheet material, the number of sheets that can be manufactured from one sheet material is small, and the production efficiency is very poor. For this reason, when manufacturing a reinforcing ring, a thin metal bar is bent into a circular shape, and both ends thereof are welded to form an annular ring body, and an extension is welded to the ring body. However, the poor production efficiency cannot be improved.

  Since the pipe joint brings both pipes into close contact with each other through a rubber elastic gasket, the tightening force by each bolt only needs to withstand the tube pulling force and does not need to be tightened as strongly as the conventional seat packing. On the other hand, even if the rubber gasket is compressed during tightening, the rubber inner peripheral surface of the gasket is exposed in the connecting pipe and causes a certain chemical reaction by directly contacting with the passing liquid in the pipe. I cannot avoid the trouble.

  The present invention has been proposed in order to improve the above-mentioned problems related to the conventional loose flange type pipe joint, and only the metal reinforcing ring is exposed in the connecting pipe when the pipe joint is tightened. It is an object of the present invention to provide a loose flange type pipe joint in which an elastic gasket such as a product is not in direct contact with the passing liquid in the pipe. Another object of the present invention is to provide a loose-flange type pipe joint in which a donut-shaped outer frame body is fitted into and integrated with an outer annular groove of a reinforcing ring, so that the welding work of the extension portion is omitted and the productivity is improved. Is to provide. Another object of the present invention is to provide a loose flange-type pipe joint in which the bolt through-holes can be easily increased / decreased only by replacing the plastic outer frame without changing the reinforcing ring.

  In the loose flange type pipe joint according to the present invention, the pipe end portions are blown out or the stub ends are welded, and a packing member is interposed between the flange end surfaces of both pipes. Combine and tighten. In the loose flange-type pipe joint according to the present invention, the packing member includes a pair of annular elastic gaskets, a metal reinforcing ring that holds both gaskets, and an outer frame body with bolt holes. An annular groove is provided on both side surfaces of the gasket, and an elastic gasket is fitted into each of the annular grooves. When the pipe joint is not tightened, the side surface of the gasket protrudes outward in the axial direction from the side surface of the reinforcing ring. At the time of tightening, the gasket is compressed, and the side surface thereof coincides with the side surface of the reinforcing ring.

  Further, in the loose flange type pipe joint according to the present invention, the packing member is composed of a pair of annular elastic gaskets, a metal reinforcing ring for holding both gaskets, and a plastic outer frame with bolt holes. An annular groove is provided on both side surfaces of the reinforcing ring, elastic gaskets are fitted in both the annular grooves, and an outer annular groove is provided on the outer peripheral surface of the reinforcing ring to form a donut-shaped plastic outer frame. The packing member may be integrated by being disposed outside the reinforcing ring and fitted along the outer annular groove of the reinforcing ring.

  In the loose flange-type pipe joint according to the present invention, it is possible to prevent contact corrosion with dissimilar metals on both loose flanges by applying chromium plating to the stainless steel reinforcing ring. The donut-shaped plastic outer frame has a planar shape corresponding to the plane of the flange, and when attached to a pipe joint, the bolt hole provided in the outer frame matches the bolt through hole of the flange. In the plastic outer frame, it is preferable that a slit is formed between each bolt hole and the outer peripheral wall of the outer frame so that the outer frame is elastically deformed and fitted along the outer annular groove of the reinforcing ring.

  In the loose flange-type pipe joint according to the present invention, the packing member is fitted with an elastic gasket made of rubber or the like in an annular groove provided on both sides of the reinforcing ring, so that the gasket is compressed when the pipe joint is tightened. The side surface of the lever coincides with the side surface of the reinforcing ring. As a result, when tightening the pipe joint, only the inner peripheral surface of the metal reinforcing ring is exposed in the connecting pipe, and the gasket made of rubber or the like is isolated from the inner peripheral surface of the connecting pipe, and the gasket passes through the pipe. Since there is no direct contact with the liquid, it is possible to avoid the trouble that the rubber of the gasket causes a chemical reaction with the passing liquid. When the loose flange type pipe joint of the present invention is used, the passing liquid in the pipe is not denatured when passing through the pipe, and the elastic gasket can be prevented from being rapidly deteriorated by a certain kind of passing liquid.

  In the loose flange type pipe joint according to the present invention, a donut-shaped outer frame is disposed outside the reinforcing ring, and is fitted and integrated along the outer annular groove of the reinforcing ring. When connecting both loose flanges, if the packing members are placed between the flange end faces of the connecting pipe and then tightened, the flanges will not be displaced or dropped when tightening both flanges. The axis of the member always coincides with that of the connecting pipe. If the outer frame body of the packing member is made of plastic, the work of elastically deforming the outer frame body and fitting it in the outer annular groove of the reinforcing ring is considerably more than the work of welding the extension to the outer peripheral side of the reinforcing ring. Since it is easy and the plastic outer frame itself is inexpensive, it is advantageous in terms of economy and time.

It is a longitudinal cross-sectional view which shows the loose flange type pipe joint which concerns on this invention, and shows the case where the bolt through-hole of a flange is four here. FIG. 2 is an end view of a loose flange and a pipe shown in the AA direction of FIG. 1. It is a side view which shows the packing member comprised by the outer ring body with a reinforcement ring, an elastic gasket, and a bolt hole. It is the cross-sectional view which cut | disconnected the packing member shown in FIG. 3 in the diameter direction. It is a front view which shows an example of a donut-shaped plastic outer frame. It is an expansion cross-sectional view which shows the non-tightening state of an elastic gasket. It is a cross-sectional view of the principal part which expands and shows the tightening state of an elastic gasket.

  The present invention will be described with reference to the drawings. In the loose flange type pipe joint 1 shown in FIG. 1, a packing member 2 (FIG. 3) is interposed between the end surfaces of the flange portions 7 and 7 of the connection pipes 4 and 4. The connection pipes 4 and 4 are the same or similar metal pipes or plastic pipes, and metal pipes and plastic pipes can also be used. As shown in FIG. 2, the metal loose flanges 3 and 3 are substantially donut-shaped in a plane and are manufactured separately from the connection pipes 4 and 4. The loose flange 3 is provided with three or four or more bolt through holes 5 at equal intervals in the circumferential direction along the circumferential direction, and the inner diameter of the flange is substantially equal to the outer diameter of the connecting pipe 4. The diameter of the circle 5a (FIG. 2) passing below the inner peripheral surface is larger than the outer diameter 7a of the flange portion 7 of the pipe 4 and the outer diameter 8a (FIG. 3) of the reinforcing ring 8 of the packing member 2.

  With respect to the loose flange-type fitting 1, various metals can be used for the loose flange 3 and the pipe 4. Preferably, the loose flange 3 is made of iron, carbon steel, stainless steel or casting, and the pipe 4 is usually used. Made of stainless steel. When the material is made of carbon steel or casting, the surface may be galvanized or plastic coated. The loose flange 3 is usually an annular plane as shown in FIG. 2, but the outer shape thereof may be a flange such as a square or an elliptical plane, or may be formed in a half mold.

  The loose flanges 3 and 3 are respectively fitted to the pipe 4 before the pipe end portion is subjected to a flange processing or a stub end (not shown) is welded to the pipe end portion. Both pipes 4, 4 are in contact with the surface of the flange portion 7 with the packing member 2 interposed therebetween, and through holes 5 (FIG. 2) of the flanges 3, 3 and bolt holes 12 of the outer frame 11 of the packing member 2. A bolt 24 is passed through (FIG. 3) and temporarily fixed with a nut 26. The packing member 2 can be accurately positioned when the bolts 24 are passed through the bolt holes 12 of the outer frame body 11, and all bolts 24 may be tightened with nuts 26 after the positioning.

  The packing member 2 used in the pipe joint 1 is composed of a metal reinforcing ring 8, an elastic gasket 10, and an outer frame body 11 with bolt holes 12. The reinforcing ring 8 usually has an annular plane and a rectangular cross section, and is manufactured from stainless steel, aluminum, copper, aluminum alloy, carbon steel, cast iron, or the like. When the loose flange 3 is made of iron, the reinforcing ring 8 made of stainless steel may be plated with chromium in order to prevent contact corrosion with dissimilar metals.

  In the reinforcing ring 8, annular grooves 14 and 16 (FIG. 6) are provided on both side surfaces thereof, and the elastic gasket 10 is fitted in each annular groove (see FIG. 3). Therefore, the annular grooves 14 and 16 have a width and an inner diameter corresponding to those of the elastic gasket 10, and the groove depth is smaller than the thickness of the elastic gasket 10. Further, an outer annular groove 18 for attaching the outer frame body 11 is formed on the outer peripheral surface of the reinforcing ring 8.

  When the metal reinforcing ring 8 is manufactured by bending an elongated metal bar having a rectangular cross section into a circular shape and welding both ends thereof, excess metal does not occur, and the number of sheets that can be manufactured from one sheet material is large, and the production efficiency is high. good. The reinforcing ring may be manufactured by punching a thin metal sheet material into an annular shape. In the reinforcing ring 8, if the materials and diameters of the pipes 4 and 4 to be connected are different, the inner diameters, lateral widths, depths, etc. of the annular grooves 14 and 16 may be varied accordingly.

  The elastic gaskets 10 and 10 are generally made of rubber that is elastic and inexpensive, or may be made of plastic such as polyurethane, polypropylene, polyester, polyamide, polyethylene, and polyacetal, and are used for piping in chemical plants and the like. In some cases, it is possible to coat the peripheral surface with a corrosion-resistant thin film. When the elastic gasket 10 is fitted into the annular grooves 14 and 16 of the reinforcing ring 8 and fixed with an adhesive, the elastic gasket is integrated with the reinforcing ring 8 so that they are not separated during use.

  As shown in FIG. 6, the elastic gaskets 10 and 10 are generally rectangular in cross section and circular in plane. If the inner diameters, lateral widths, depths, etc. of the annular grooves 14 and 16 are different, the elastic gaskets 10 and 10 are The shapes of the elastic gaskets 10 and 10 are also different. The elastic gasket 10 may be subjected to some deformation such as an inverted V-shaped cross section so that the elastic gasket 10 is easily crimped toward the reinforcing ring 8. The elastic gaskets 10 and 10 protrude outward from both side surfaces of the reinforcing ring 8 when fitted (see FIG. 6). When the elastic gaskets 10 and 10 are compressed and deformed from the outside during tightening to reduce the thickness to 50 to 95%, the reinforcing ring 8 The both side surfaces and the vertical plane coincide with each other (see FIG. 7).

  The outer frame 11 has a substantially donut-shaped planar shape, and generally has a planar shape corresponding to the plane of the flange 3, and its inner diameter is slightly smaller than the outer diameter of the reinforcing ring 8. The donut-shaped outer frame body 11 is fitted into an outer annular groove 18 formed on the outer peripheral surface of the reinforcing ring 8. The inner diameter of the outer frame 11 is slightly smaller than the outer diameter of the reinforcing ring 8, and the inner peripheral wall 19 (FIG. 5) is fixed to the reinforcing ring 8 by cutting so that the cross section of the inner peripheral wall 19 (FIG. 5) is triangular. It will not detach from the reinforcing ring (see FIG. 6). A plurality of positioning bolt holes 12 protruding outward in the radial direction are formed in the outer frame body 11, and the bolts 24 pass through the bolt holes 12 when the pipe joint 1 is assembled.

  The outer frame body 11 can be manufactured from a hard plastic plate, a metal plate, a hard paperboard, or the like, and is preferably made of hard plastic in consideration of cost and durability. In the plastic outer frame 11, the hard heat-resistant plastic is an unsaturated polyester resin, a phenol resin, an epoxy resin, a polyamide resin, a polyacetal resin, or the like, and a wider range of resins can be used if glass fiber is filled. The plastic outer frame 11 has a thin plate shape with a thickness of 1.5 to 3 mm as shown in FIG. 4 and may be compression molded or stamped from a plastic sheet.

  In the outer frame body 11, the bolt hole 12 has an inner diameter slightly larger than the diameter of the bolt 24 of the pipe joint 1. The number of bolt holes 12 is usually the same as the number of bolt through holes 5 in the flange 3, and is determined according to the number and position of the bolt through holes 5. If the number of bolt through holes 5 in the flange 3 increases, Accordingly, it can be formed at intervals of 90 degrees in the circumferential direction, or can be increased to 5 or more. In the plastic outer frame 11, slits 20 (FIG. 5) are formed between the bolt holes 12 and the inner peripheral wall of the plate, thereby elastically deforming the plastic plate and along the outer annular groove 18 of the reinforcing ring 8. It is possible to fit.

  As shown in FIG. 1, the loose flange-type pipe joint 1, after fitting the loose flange 3 to the pipes 4 and 4, respectively, pipes the end of the pipe or welds the stub end. 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, when the packing member 2 is interposed between the end surfaces of the flange portion 7 of the pipe 4, the elastic gaskets 10, 10 of the packing member 2 are removed from both side surfaces of the reinforcing ring 8 when fitted as shown in FIG. 6. It protrudes toward.

  After the packing member 2 is interposed between the end faces of the flange portion 7 of the pipe 4, the loose flanges 3 and 3 are tightened with a plurality of bolts 24 and nuts 26. If a half-type loose flange is used, the flange can be fitted and fixed after swaging. Further, if the loose flange is changed to one having a different number of bolt holes, only the plastic outer frame 11 needs to be replaced in accordance with this, and it is not necessary to change the reinforcing ring 8. When the flanges 3 and 3 are tightened, the front end surface of the loose flange 3 comes into contact with both side surfaces of the reinforcing ring 8 as shown in FIG.

  At the time of this assembly, for example, it is preferable that the front end portion of the pipe 4 is swung out after fitting the flange 3 to the front end portion of the pipe 4 and a flange 3 (not shown) and then the flange 3. At the piping site, when the flanges 7 of the pipes 4, 4 arranged in the vertical or inclined direction are brought close to each other and the two flanges 3, 3 are accurately positioned, this temporary fixing metal fitting is placed immediately behind the flange 3. If arranged, even if the flange 3 is heavy due to the attachment of the temporary fixing metal fitting, it is possible to prevent the fall or displacement.

  Further, when the pipes 4 and 4 are horizontally arranged, the reinforcing ring can be accurately positioned by inserting the bolt 24 into the bolt hole 12 of the reinforcing ring 8 and temporarily fixing it. When this pipe connection work is completed, it is necessary to fix the pipe 4 to a wall surface or the like. During this fixing operation, the fitted stopper (not shown) is moved along the pipe peripheral surface to the mounting position of a fixing bracket (not shown) such as a U-bolt, and is stopped inside the fixing bracket. The pipes 4 and 4 may be fixed by tightening the fixing metal fittings.

  When the tightening of the loose flange-type pipe joint 1 is completed, as shown in FIG. 7, the elastic gaskets 10 and 10 are compressed and deformed from the outside to reduce the thickness, and the both sides of the reinforcing ring 8 and the vertical plane coincide with each other. As a result, when the pipe joint 1 is used, only the inner peripheral surface 8a of the stainless steel reinforcing ring 8 is exposed in the connection pipes 4 and 4, and the gaskets 10 and 10 made of rubber are connected to the inner peripheral surface 4a of the connecting pipe. Therefore, the elastic gasket is not in direct contact with the passing liquid in the pipe, and the trouble that the rubber or the like of the elastic gasket causes a chemical reaction with the passing liquid can be avoided. Further, the passing liquid in the pipes 4 and 4 is not denatured when passing through the pipes, and it is possible to prevent the elastic gasket 10 from being rapidly deteriorated by the passing liquid such as a solvent.

  Next, the present invention will be described based on examples, but the present invention is not limited to the examples. In the loose flange-type pipe joint 1 shown in FIG. 1, the iron loose flanges 3, 3 have a substantially donut shape as shown in FIG. 2 and are formed separately from the connection pipes 4, 4. The pipes 4 and 4 are the same or similar stainless steel pipes. The loose flange 3 is provided with three 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 4, and the circle 5 a that passes below the inner peripheral surface of each through hole 5. The diameter is larger than the outer diameter of the flange portion 7 of the pipe 4 and the outer diameter of the reinforcing ring 8.

  As shown in FIGS. 3 and 4, the packing member 2 includes a stainless steel reinforcing ring 8, a rubber elastic gasket 10, and a plastic outer frame body 11 with bolt holes 12. The reinforcing ring 8 preferably has a strength substantially equal to or higher than the strength of the connection pipe 4 with respect to the internal pressure of the pipe. Therefore, the thickness of the reinforcing ring is set to be substantially the same as the thickness of the connection pipe 4. As shown in FIG. 6, the annular reinforcing ring 8 is provided with an outer groove 18 on the outer peripheral surface thereof and annular grooves 14 and 16 on both side surfaces thereof. The reinforcement ring 8 made of stainless steel is plated with chromium in order to prevent contact corrosion when the loose flange 3 is made of iron.

  The plastic outer frame body 11 (FIG. 3) fitted to the outside of the reinforcing ring 8 is manufactured by punching from an unsaturated polyester resin sheet having a thickness of 2 mm. The plastic outer frame 11 has a donut-shaped planar shape corresponding to the plane of the flange 3. Three bolt holes 12 are formed in the plastic outer frame 11 at equal intervals in the circumferential direction.

  The inner diameter of the plastic outer frame 11 is slightly smaller than the outer diameter of the reinforcing ring 8, and the cross section of the inner peripheral wall 19 is cut into a triangular shape (see FIG. 6). In the plastic outer frame 11, a slit 20 (FIG. 5) is formed between each bolt hole 12 and the inner wall of the plate, and the inner diameter of the plate can be expanded by the slit along the outer annular groove 18 of the reinforcing ring 8. After the insertion, the outer frame body 11 returns to its original state by elastic deformation. Since the inner diameter of the plastic outer frame 11 is slightly smaller than the outer diameter of the reinforcing ring 8, the plate is fixed and integrated with the reinforcing ring 8 by fitting the reinforcing ring 8 into the outer annular groove 18.

  On the other hand, the elastic gaskets 10 and 10 are made of rubber rich in elasticity, and have a rectangular cross section and an annular plane as shown in FIG. The elastic gaskets 10 and 10 are substantially equal to the inner diameter and the lateral width of the annular grooves 14 and 16 of the reinforcing ring 8, and the thickness thereof is considerably larger than the depth of the annular grooves 14 and 16. The elastic gaskets 10 and 10 are fitted into the annular grooves 14 and 16 of the reinforcing ring 8 and fixed with an adhesive, and both elastic gaskets are integrated with the reinforcing ring 8.

  The loose flange 3 is fitted into the pipe 4 before the end of the pipe is pulled out. Both pipes 4, 4 are in contact with the surface of the flange portion 7 with the packing member 2 interposed therebetween, and the nuts 26 are passed through the bolts 24 through the through holes 5 of the loose flanges 3, 3 and the bolt holes 12 of the plastic outer frame 11. Temporarily fix with. The reinforcing ring 8 can be accurately positioned by passing the bolts 24 through the bolt holes 12 of the plastic outer frame body 11, and all the bolts 24 may be tightened with nuts 26 after the positioning.

  In the loose flange-type pipe joint 1, the pipes 4 and 4 are brought into close contact with the rubber elastic gasket 10 that is easily compressed and deformed. Therefore, the tightening force by each bolt 24 only needs to withstand the tube pulling force. For this reason, the number of tightening bolts can be almost halved as compared with the prior art, and the outer diameters of the loose flange 3 and the flange portion 7 can be reduced as compared with the prior art. Further, in the loose flange 3, even if the inner diameter is substantially equal to the outer diameter of the connection pipe 4, the outer diameter and the thickness can be reduced as compared with the conventional flange. Therefore, as shown in FIG. It is possible to make the whole compact by recessing other than 28.

  In the loose flange type pipe joint 1, the front end surface of the loose flange 3 is located on both side surfaces of the reinforcing ring 8 when tightening between the flanges 3 and 3, even if the tightening force by each bolt 24 can withstand the tube pulling force. Since the elastic gaskets 10 and 10 are compressed and deformed from the outside to reduce the thickness, the both sides of the reinforcing ring 8 coincide with the vertical plane (see FIG. 7). ). As a result, when the pipe joint 1 is used, only the inner peripheral surface 8a of the stainless steel reinforcing ring 8 is exposed in the connecting pipes 4 and 4, and the rubber gaskets 10 and 10 are exposed from the inner peripheral surface 4a of the connecting pipe. It is isolated, and the trouble that the rubber of the gasket causes a chemical reaction with the passing liquid can be avoided.

DESCRIPTION OF SYMBOLS 1 Loose flange type pipe joint 2 Packing member 3, 3 Loose flange 4, 4 Connection pipe 5 Bolt through-hole 7 Brim part 8 Reinforcement ring 10 Elastic gasket 11 Outer frame body 12 Bolt hole 14, 16 Inner annular groove 18 Outer annular groove 20 Slit 24 Bolt 26 Nut

Claims (5)

  In the loose flange type pipe joint that pipes out the pipe end or welds the stub end and interposes a packing member between the flange end faces of both pipes, and then joins and tightens both loose flanges fitted together. The packing member is composed of a pair of annular elastic gaskets, a metal reinforcing ring that holds both gaskets, and an outer frame body with bolt holes, and annular grooves are provided on both side surfaces of the reinforcing ring. The elastic gaskets are fitted in both annular grooves, and when the pipe joint is not tightened, the side surface of the gasket protrudes outward in the axial direction from the side surface of the reinforcing ring, and when the pipe joint is tightened, the gasket is compressed and the side surface is compressed. Loose flange type pipe joint where the side of the reinforcing ring and the vertical surface coincide.   In the loose flange type pipe joint that pipes out the pipe end or welds the stub end and interposes a packing member between the flange end faces of both pipes, and then joins and tightens both loose flanges fitted together. The packing member is composed of a pair of annular elastic gaskets, a metal reinforcing ring that holds both gaskets, and a plastic outer frame with bolt holes, and annular grooves are provided on both sides of the reinforcing ring. Then, an elastic gasket is fitted into each of the annular grooves, an outer annular groove is provided on the outer peripheral surface of the reinforcing ring, and a donut-shaped plastic outer frame is disposed outside the reinforcing ring, Loose flange type pipe joint that integrates packing members by fitting along an annular groove.   The loose flange-type pipe joint according to claim 1 or 2, wherein contact corrosion with dissimilar metals is prevented with respect to both loose flanges by applying chromium plating to the reinforcing ring made of stainless steel.   The donut-shaped plastic outer frame has a planar shape corresponding to the plane of the loose flange, and when attached to a pipe joint, the bolt hole of the outer frame matches the bolt through hole of the flange. Loose flange fitting.   The plastic outer frame body, wherein a slit is formed between each bolt hole and the outer peripheral wall of the outer frame body, whereby the outer frame body is elastically deformed and fitted along the outer annular groove of the reinforcing ring. The loose flange type pipe joint according to 2.

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