JP3171067U - Stainless steel pipe joints for underground use - Google Patents

Abstract

An object of the present invention is to provide an anti-seismic stainless steel pipe joint that can prevent a connection pipe from being detached when an earthquake or ground subsidence occurs. An underground pipe joint 1 includes a stainless steel pipe receiving pipe 3 provided with annular protrusions 6 and 7 in the vicinity of the pipe end, and a stainless steel pipe insertion pipe provided with the annular protrusion behind the pipe end. And an elastic gasket 8 in liquid-tight contact with the receiving tube 3 and the insertion tube 5, and a half-shaped housing 10 that fixes the receiving tube 3 and the elastic gasket 8 and holds the insertion tube 5. [Selection] Figure 1

Description

  The present invention relates to a stainless steel pipe joint used in water pipes, and relates to an earthquake-resistant stainless steel pipe joint that can prevent connection pipes from being detached when an earthquake or ground subsidence occurs.

  Conventionally, asbestos pipes, concrete pipes, cast iron pipes, etc. have been used for underground pipes buried in the ground, but recently, ductile cast iron pipes, carbon steel are used based on durability, strength, and hygiene. Steel pipes and plastic pipes are mainstream. Among these water pipes, the use results of ductile cast iron pipes that can use earthquake-resistant pipe joints are rapidly increasing. On the other hand, stainless steel pipes are widely used as industrial pipes because of their excellent corrosion resistance and hygiene, and are also used mainly for small-diameter water pipes in the field of underground water pipes. In the case of stainless steel pipes, in the field of water pipes with a nominal diameter of 75A or more, the seismic type pipe joints that connect straight pipes have not been developed. There is only a small track record of adoption as a water pipe for welding connections.

  JP-A-11-2374, JP-A-11-63328, JP-A-2001-330185, JP-A-2002-188773 and the like have been proposed as underground ductile cast-iron pipes, which are cast iron insertion pipes. Is pushed into a receiving pipe made of cast iron and joined. There are two types of ductile cast iron pipes: a lock ring for preventing slip-out and a water-seal gasket to be attached to the receiving pipe when the pipe is joined at the work site, and a type in which the lock ring and gasket are completely installed at the time of shipment from the factory. . Ductile cast iron pipes can adapt to straight pipe sections against large ground fluctuations such as earthquakes and land subsidences, and finally a separation prevention function works for large pulling forces exceeding the binding force such as earthquakes during use. The water flow through the pipeline is maintained.

Japanese Patent Laid-Open No. 11-2374 JP-A-11-63328 JP 2001-330185 A JP 2002-188773 A

  Ductile cast iron pipes can adapt to straight ground sections due to large ground fluctuations, but are generally thick and have a mortar lining on the inner peripheral surface. Construction must be carried out in the state of being lifted by heavy machinery. When inserting the insertion tube into the receiving tube and joining it, the frictional force between the gasket and the cast iron tube is large and cannot be joined by human power, so auxiliary equipment such as a lever hoist and hydraulic cylinder is required. At the time of this joining, the mounting position of the lock ring and the gasket is likely to shift, and it is difficult to check whether the mounting is correct. Further, in the ductile cast iron pipe, there is a problem that the mortar lining and the epoxy coating on the inner peripheral surface are peeled off due to aging.

  On the other hand, if the stainless steel pipe can be applied as a water pipe, the pipe weight can be reduced by about 40 to 60% in the range of the nominal diameter of the pipe of 75 to 300 mm compared to the conventional ductile cast iron pipe, and the pipe workability is improved by reducing the weight. be able to. Stainless steel pipes are protected by a chromium oxide passivated film, so they are not easily rusted and have excellent corrosion resistance.If the environment such as the soil environment is suitable, durability of 100 years can be expected. Such durability is not expected for conventional cast iron pipes. Stainless steel pipes are clean and sanitary compared to cast iron pipes, and are suitable as water pipes in which the quality of water is always an issue.

  The present invention has been proposed in order to improve the above-mentioned problems associated with conventional ductile cast iron pipes, and the stainless steel pipes to be connected are relatively light and the pipe workability is improved, and they are not easily rusted and have excellent corrosion resistance. The purpose of this is to provide a stainless steel pipe joint that can be buried in the ground as a water pipe by connecting it. Another object of the present invention is to provide a seismic type stainless steel pipe joint that can extend and contract, so that a long straight pipe portion is connected in underground water pipes, and has good pressure resistance and separation prevention power. Another object of the present invention is that it is installed in the same pipe as the earthquake-resistant stainless steel pipe joint, and is connected to a deformed pipe such as a bend, cheese or a reducer, so that the deformed pipe is not stretched even if thrust by water pressure acts on it. It is to provide a stainless steel pipe joint.

  The underground stainless steel pipe joint according to the present invention connects a receiving pipe whose diameter is expanded at a pipe end portion and an insertion pipe that is inserted into the pipe end portion of the receiving pipe at the pipe end portion. The pipe joint of the present invention comprises a stainless steel pipe receiving pipe with an annular protrusion provided near the pipe end, a stainless steel pipe insertion pipe with an annular protrusion provided behind the pipe end, and a receiving pipe and an insertion pipe. An elastic gasket that is in contact with the housing and a half-type housing that fixes the receiving pipe and the elastic gasket and holds the insertion pipe. The elastic gasket has a substantially U-shaped or L-shaped cross section, the inner peripheral surface of the small diameter portion is in contact with the insertion tube, and the inner peripheral surface or end surface of the large diameter portion is in contact with the receiving tube, and the inner periphery of the housing On the surface, there are an annular groove that fits with the annular projection of the receiving pipe, an annular groove with a rectangular cross section that fits with the elastic gasket, and an annular groove that fits loosely or closely in the axial direction with the annular projection of the insertion pipe Form.

  In the stainless steel pipe joint according to the present invention, the annular protrusions provided on the receiving port and the insertion pipe may be formed on the outer surface of the stainless steel pipe by plastic working or by attaching a ring material by welding. Further, in the housing, it is preferable to provide one or a plurality of peep holes along the circumference of the annular groove that fits with the annular protrusion provided on the receiving pipe and the insertion pipe.

  In the case of a stainless steel pipe joint that is extendably connected, the elastic gasket has a substantially U-shaped cross section, the inner peripheral surface of the small diameter portion is the insertion tube, and the inner peripheral surface of the large diameter portion is the receiving tube. An annular groove closely contacting with the annular protrusion of the receiving pipe, an annular groove having a rectangular cross section closely fitting with the elastic gasket, and an annular protrusion of the insertion pipe are axially disposed on the inner peripheral surface of the housing. It is preferable to form a wide annular groove that is slidably fitted in the slidable member. In other cases, the annular protrusion provided on the receiving pipe may be a flange-shaped ring member attached to the pipe end. At this time, the elastic gasket has a substantially L-shaped cross section, the inner peripheral surface of the small diameter portion is in contact with the insertion tube and the end surface of the large diameter portion is in contact with the receiving tube, and the inner peripheral surface of the housing is provided with the receiving port. An annular groove having a rectangular cross section to be fitted with the ring material and the elastic gasket of the pipe and a wide annular groove to which the annular projection of the insertion pipe is slidably fitted in the axial direction are formed.

  Another stainless steel pipe joint that can be extended and contracted includes a stainless steel pipe receiving pipe with an annular protrusion provided near the pipe end, a stainless steel pipe insertion pipe with an annular protrusion provided near the pipe end, a receiving pipe and an insertion pipe. You may comprise by the elastic gasket which contacts liquid-tightly, and the half type | mold housing which fixes a receptacle pipe | tube and an elastic gasket, and hold | maintains an insertion pipe. On the inner peripheral surface of the housing, there are formed an annular groove that closely fits with the annular projection of the receiving pipe and an annular groove of a rectangular cross section that fits tightly with the elastic gasket. A lock ring is fitted and fixed on the peripheral side, and the lock ring abuts against the annular protrusion of the insertion pipe when the pipe joint is extended to prevent the insertion pipe from coming out.

  In the case of a non-stretchable stainless steel pipe joint that connects to a deformed pipe, an annular groove that closely fits the annular projection of the receiving pipe and an elastic gasket closely fit on the inner peripheral surface of the short housing. You may form the annular groove of a rectangular cross section, and the annular groove closely fitted with the annular protrusion of an insertion tube. Another stainless steel pipe joint has an annular groove on the inner peripheral surface of the housing that closely fits the annular protrusion of the receiving pipe, an annular groove that has a rectangular transverse cross section that fits tightly on the elastic gasket, and an insertion pipe. A wide annular groove into which the annular protrusions are fitted may be formed, and the stopper rings may be closely fitted on both sides of the annular protrusion of the insertion tube in the wide annular groove.

  The stainless steel pipe joint according to the present invention is such that when an austenitic stainless steel pipe is connected, the insertion pipe can be moved back and forth relatively easily even if the thermal conductivity of the steel pipe is low and the coefficient of thermal expansion is large. Therefore, it is excellent in the expansion and contraction performance and the ability to prevent detachment, and can be used in a high temperature environment in underground. In addition, since austenitic stainless steel pipes have good elongation and high stretchability, the pipe end portion of the receiving pipe is formed into a large diameter by plastic working and an annular protrusion is provided in the vicinity of the pipe end. An annular protrusion can be provided behind the end, and if the processing machine is brought to the site, it can be easily processed and assembled at the site where the pipe is embedded.

  The stainless steel joint according to the present invention makes it possible to embed a stainless steel pipe in the ground as a water pipe, and the stainless steel pipe to be connected is relatively light compared to a cast iron pipe and has improved piping workability and is not easily rusted. Corrosion resistance is excellent. Since the stainless steel pipe joint of the present invention is extendable, connecting a long straight pipe part in a water pipe can reliably prevent the connection pipe from being detached even in the occurrence of a considerably strong earthquake such as the Great Hanshin Earthquake or land subsidence. .

  The stainless steel pipe joint according to the present invention has good pressure resistance without water leakage and other abnormalities even if it is held for 5 seconds or more with a water pressure of 6 MPa. In addition, when a tensile load of 3 × D (nominal diameter) KN is applied in a state where this stainless steel pipe joint is joined to the straight pipe portion, there is no detachment and other abnormalities, and the detachment prevention force is good. Another stainless steel pipe joint according to the present invention is attached to the same pipe as the seismic type stainless steel pipe joint, and when connected to a deformed pipe such as a bend, cheese or reducer, even if thrust by water pressure acts on the deformed pipe, it does not expand and contract Therefore, it is unnecessary to install a stopper such as a concrete block for preventing the movement of the pipe joint.

It is a longitudinal section showing an example of a stainless steel pipe joint concerning the present invention. It is a side view of the housing which shows an insertion tube in a cross section. It is a longitudinal cross-sectional view which shows the extendable stainless steel pipe joint which is the 1st modification of this invention. It is a longitudinal cross-sectional view which shows the extendable stainless steel pipe joint which is the 2nd modification of this invention. It is a longitudinal cross-sectional view which shows the non-expandable stainless steel pipe joint which is the 3rd modification of this invention. It is a longitudinal cross-sectional view which shows the non-expandable stainless steel pipe joint which is the 4th modification of this invention.

  As shown in FIG. 1, the underground pipe joint 1 according to the present invention is inserted into the pipe end portion 2 of the receiving pipe 3 and the receiving pipe 3 having the pipe end portion 2 expanded in diameter. Connect the insertion tube 5 to be connected. The pipe joint 1 includes a receiving pipe 3 provided with an annular protrusion 6, an insertion pipe 5 provided with an annular protrusion 7, an elastic gasket 8 in liquid-tight contact with the receiving pipe 3 and the insertion pipe 5, a receiving pipe 3 and an elastic A half-shaped housing 10 that holds the gasket 8 and holds the insertion tube 5 is formed.

  The receiving pipe 3 and the insertion pipe 5 are both made of stainless steel pipes, and can have various thicknesses and diameters. The nominal diameter of the tubes 3 and 5 is about 80A to 300A, but a larger diameter is also possible. On the other hand, for example, the housing 10 is preferably made of cast stainless steel, and the bolts 24 and nuts 26 for fastening are also preferably made of stainless steel. Since the pipe joint 1 is piped in wet soil, contact corrosion of dissimilar metals can be prevented in the ground if each member in the pipe joint is made of the same material stainless steel.

  The annular projections 6 and 7 are provided to prevent the receptacle tube 3 and the insertion tube 5 from being detached. In the receptacle tube 3 or the insertion tube 5 which is a stainless steel tube, the annular projections 6 and 7 are formed on the outer surface by plastic working. 7 or a ring material (not shown) may be attached by welding instead of these annular protrusions, and an example is the ring material 38 of FIG. This type of ring material is stainless steel similar to tubes 3 and 5.

  The annular elastic gasket 8 is usually made of a relatively hard synthetic rubber such as ethylene / propylene rubber (EPDM) or plastic, and even if the surface is further coated with a heat resistant resin coating or a resin coating with low frictional resistance. Good. The elastic gasket 8 has a substantially U-shaped or L-shaped cross section and is preferably hollow. At this time, if the elastic gasket 8 is hollow, it is included in the U-shape or L-shape even if its cross-sectional shape is substantially C-shaped or M-shaped.

  The elastic gasket 8 has a small-diameter portion 12 on the side surface on the insertion tube side and a large-diameter portion 14 on the side surface on the receiving tube side, and the inner diameter of the small-diameter portion 12 is smaller than the outer diameter of the insertion tube 5 in an uncompressed state. The inner diameter of the diameter portion 14 is smaller than the outer diameter of the receiving pipe 3 or its end face abuts on the receiving pipe. The elastic gasket 8 has a small-diameter portion 12 corresponding to the insertion tube 5 and a large-diameter portion 14 corresponding to the receiving tube 3, so that when the housing 10 is tightened, the elastic gasket 8 is pressed inward in the diametrical direction to reliably achieve a water-sealed state. To do.

  The elastic gasket 8 has a substantially U-shaped or L-shaped cross section, and in the cross section, the inner walls of the small diameter portion 12 and the large diameter portion 14 are tapered inward as they approach the inner periphery. preferable. When water flows into the pipe joint 1 by such a cross-sectional shape, the pressurized water that has entered the inside of the elastic gasket 8 pushes the gasket from the inside and spreads the gasket to the inner peripheral surface and both side walls of the rectangular annular groove 30. By pressing, the water seal state is further increased.

  The housing 10 is usually made of cast stainless steel, and the fastening bolts 24 and the nuts 26 are made of stainless steel. A member in which the housing 10 and the bolts 24 and nuts 26, cast iron, carbon steel, or the like are subjected to plastic coating or lining can also be used. Contact corrosion can be prevented by these members not contacting the stainless steel piping which is the receptacle tube 3 and the insertion tube 5 directly.

  The housing 10 is normally halved as shown in FIG. 2, and even if both sides of the semi-annular bodies 20 and 22 are fixed with bolts and nuts 24 and 26 as shown, one side is hinged. Only the opposite side may be fixed with bolts and nuts. This housing can be divided into three or more.

  On the inner peripheral surface of the housing 10, an annular groove 28 that fits with the annular protrusion 6 of the receiving pipe 3, an annular groove 30 that has a rectangular cross section that fits with the elastic gasket 8, and the annular protrusion 7 of the insertion pipe 5 and the shaft And an annular groove 32 that fits loosely or tightly in the direction. The annular grooves 28 and 30 can be combined into one annular groove as shown in FIG. 3, but the annular grooves 30 and 32 can be combined as long as they are non-expandable. Further, instead of the annular groove 32, as shown in FIG. 4, a lock ring 58 is fitted and fixed on the inner peripheral side of the annular projection of the receiving pipe, and is inserted between the enlarged diameter inclined wall of the receiving pipe and the locking ring 58. The annular protrusion of the tube may be movable in the axial direction.

  Next, although this invention is demonstrated based on an Example, this invention is not limited to an Example. FIG. 1 shows a cross-sectional view of a seismic-resistant stainless steel pipe joint 1 suitable for being buried in the ground as a water pipe.

  The pipe joint 1 usually connects the receiving pipe 3 and the insertion pipe 5 of a stainless steel pipe having the same diameter. The receiving pipe 3 is formed by forming the front pipe end portion 2 into a large diameter by plastic working. The receiving pipe 3 is provided with an annular protrusion 6 near the pipe end by plastic working, while the insertion pipe 5 is provided with an annular protrusion 7 behind the pipe end by plastic working. For example, in the case of a stainless steel pipe having a nominal diameter of 100 A, the pipes 3 and 5 have a thickness of 3 mm and an outer diameter of 114.3 mm, and the pipe end portion 2 of the receiving pipe 3 has a thickness of about 2.9 mm and an outer diameter of 124. The axial width is set to 3 mm and about 110 mm. The annular protrusions 6 and 7 are provided at a position of about 25 mm from the pipe end in the receiving pipe 3, and are provided at a position of about 140 mm from the pipe end in the insertion pipe 5. The annular protrusions 6 and 7 have a height of about 6 mm and a width of 10 mm.

  The ring-shaped elastic gasket 8 is made of chlorine-resistant EPDM. EPDM has slightly better ozone resistance and heat aging resistance than butyl rubber, weather resistance, cold resistance, polarity, solvent resistance, inorganic chemical resistance, and higher rebound resilience than butyl rubber. It is a synthetic rubber with higher production volume than butyl rubber in terms of performance.

  The elastic gasket 8 is a rectangular section having a substantially U-shaped cross section, the side surface on the insertion tube side is the small diameter portion 12, and the side surface on the receiving tube side is the large diameter portion 14. The thickness of the small diameter portion 12 is about 8 to 12 mm, which is about twice the thickness of the large diameter portion 14. When the gasket 8 is attached, the inner peripheral surface of the small diameter portion 12 is brought into contact with the outer peripheral surface of the insertion tube 5 and the inner peripheral surface of the large diameter portion 14 is brought into contact with the outer peripheral surface of the receiving tube 3. 14 is crimped almost evenly. For example, for a tube having a nominal diameter of 100A, the elastic gasket 8 having a U-shaped cross section is defined to have a width of 30 mm, an inner diameter of the small diameter portion 12 of less than 114 mm, and an inner diameter of the large diameter portion of less than 118 mm.

  As shown in FIG. 2, the half-divided housing 10 is composed of semi-annular bodies 20 and 22 having a pair of extensions 16 and 18 outward in the diameter direction. For example, for a tube having a nominal diameter of 100A, the housing 10 has an inner diameter of 116.3 mm, an outer diameter of 158 mm, and an axial width of 165 mm. Each of the extension portions 16 and 18 is provided with two bolt through holes (not shown), and the bolt through holes may be circular holes or square holes for preventing co-rotation. Regarding the fastening bolt 24 and the nut 26 of the housing 10, the bolt may be a normal bolt or a half root angle bolt that prevents co-rotation.

  The housing 10 is made of cast stainless steel, and the bolts 24 and nuts 26 that pass through the extensions 16 and 18 are made of stainless steel. In the case of underground pipes, pipes are placed in wet soil, so the materials of the housing 10, bolts 24, and nuts 26 that contact the stainless steel pipes 3, 5 of the pipe body prevent contact corrosion of dissimilar metals. Therefore, it is desirable to be made of stainless steel made of the same material as the pipe body.

  An annular groove 28 that fits with the annular protrusion 6 of the receiving pipe 3, an annular groove 30 with a rectangular cross section that fits with the elastic gasket 8, and an inner peripheral surface of the housing 10, that is, the semicircular annular bodies 20 and 22, are inserted. An annular protrusion 7 of the tube 5 and a wide annular groove 32 that loosely fits in the axial direction are formed. For example, in the case of a pipe housing 10 having a nominal diameter of 100A, an annular groove 28 having a width of 10 mm is provided at a position 12 mm from the front end face, and an annular groove 30 having a width of 30 mm is provided at a position 30 mm from the front end face. An annular groove 32 having an axial width of 90 mm and an inner diameter of 128 mm is provided at a position 68 mm from the surface.

  Prior to the assembly of the joint, the receiving pipe 3 is formed with a pipe end portion 2 having a large diameter and further provided with an annular protrusion 6 in the vicinity of the pipe end, while the insertion pipe 5 has an annular protrusion on the rear side of the pipe end. 7 is required. Since these processes can be performed by plastic processing, they are generally processed at a factory. However, it is also possible to bring a processing machine to a work site where pipes are buried and perform processing. In order to assemble the pipe joint 1, the elastic gasket 10 is usually fitted into the insertion pipe 5, and then the insertion pipe is inserted into the pipe end of the mouth pipe 3, and the elastic gasket 8 is received at the pipe end position of the mouth pipe 3. Move. The tube end of the insertion tube 5 enters about 70 mm from the elastic gasket 8, that is, the receiving tube 3. Next, the semi-annular bodies 20 and 22 of the housing 10 are fitted from the outside, and the housing 10 is fastened with the four bolts 24 and the nuts 26. As a result, the housing 10 fixes the receiving pipe 3 and the elastic gasket 8 and holds the insertion pipe 5 so as to be slidable in the front-rear direction. The elastic gasket 8 is pressed inward in the diameter direction to achieve a water-sealed state.

  Further, in the annular groove 28, peep holes 31 are provided at several places on the circumference thereof. Each peephole 31 penetrates from the inner surface to the outer surface of the housing 10, so that it can be confirmed whether or not the annular protrusion 7 is completely fitted in the annular groove 28 by the peephole.

  In the pipe joint 1, each member does not come into contact with a metal other than stainless steel, and contact corrosion specific to stainless steel does not occur in the ground. When water is passed through the pipe joint 1, the pressurized water that has entered the inside of the elastic gasket 8 pushes the gasket from the inside and presses it against the inner peripheral surface and both side walls of the rectangular annular groove 30, thereby further enhancing the water-sealed state. In the pipe joint 1, since the insertion pipe 5 can move back and forth, the expansion and contraction of the pipe due to earthquake, ground subsidence, geothermal generation, etc. can be absorbed in the joint part. Since the pipe joint 1 can tighten and release the housing 10 with only the bolt 24 and the nut 26, the workability is much better than the ductile cast iron pipe in which the stopper part is cast integrally with the joint body. .

  The following accuracy test was conducted on the pipe joint 1 of Example 1. In this accuracy test, the sample is a stainless steel pipe (SUS304, Sch10S) having a nominal diameter of 100A conforming to JIS-G3459, which is used as the inlet pipe 3 and the insertion pipe 5.

(1) Pressure resistance test
The test procedure is to support the ends of the receiving tube 3 and the insertion tube 5 freely, fill water so that no air remains in the pipe joint 1, apply a water pressure of 6.0 MPa and hold for 5 seconds or more. Check for leaks. As a result of this test, water leakage and other abnormalities did not occur in the pipe joint 1.

(2) Detachment prevention test
The test procedure is to check for pipe removal and the like when a tensile load of 3 × D (nominal diameter) KN is applied in a state where the pipe fitting 1 is joined to the receiving pipe 3 and the insertion pipe 5. In this test, since D (nominal diameter) is 100, the tensile load F = 3 × 100 = 300 KN. In this test result, in the pipe joint 1, no pipe removal and other abnormalities occurred.

(3) Elasticity test
The test method is to fill the pipe fitting 1 with water so that no air remains, and apply a maximum working pressure of 3.0 MPa to the pipe with a pipe length of ± 1% (standard: 4000 mm = ± 40 mm). When one round trip is repeated for 20 round trips, water leaks are checked. As a result of this test, water leakage and other abnormalities did not occur in the pipe joint 1.

(4) Bending test
The test method is to fill the pipe joint 1 with water so that no air remains and apply a maximum working pressure of 3.0 MPa and bend to an allowable bending angle of 4 ° (bending angle = 8 °). Check for leaks, depilation, etc. In this test result, in the pipe joint 1, water leakage, pipe removal, and other abnormalities did not occur.

  The performance of the pipe joint 1 satisfies the performance as an earthquake-resistant type joint according to the National Land Development Technology Research Center “Baseline Pipe Earthquake-resistant Joint Standard (draft)” (1977). That is, the amount of expansion / contraction of the performance item is that the standard performance is ± 1% of the pipe length (S-1 class). The standard performance of the performance item separation prevention force is 3D (nominal diameter) KN (Class A). The allowable bending angle of the performance item is 4 ° at nominal diameters 80A to 300A.

  In the second and subsequent embodiments, modifications of the present invention are shown, and the same members as those in the first embodiment are not given the same numbers or numbers. In the pipe joint 34 shown in FIG. 3, in the receiving pipe 36, a ring member 38 having a rectangular cross section is welded to the pipe end instead of the annular protrusion 6 of the first embodiment in a flange shape. It is the same. The elastic gasket 40 is a rectangular section having a substantially L-shaped cross section. When the gasket is attached, the inner peripheral surface of the small-diameter portion 42 is brought into contact with the outer peripheral surface of the insertion tube 5 and the end surface of the large-diameter portion 44 is brought into contact with the side surface of the ring member 38 of the receiving tube 36 to be crimped.

  The inner circumferential surface of the half-split housing 46 is loosely fitted in the axial direction with the annular groove 48 having a rectangular cross section for fitting with the ring member 38 and the elastic gasket 40 of the receiving pipe 36 and the annular protrusion of the insertion pipe 5. And a wide annular groove 50 to be formed. For example, in the case of a pipe housing 46 having a nominal diameter of 100A, the axial width thereof is 165 mm, an annular groove 48 having a width of 30 mm is provided at a position 12 mm from the front end face, and an axial direction is provided at a position 62 mm from the front end face. An annular groove 50 having a width of 90 mm and an inner diameter of 128 mm is provided.

  In the pipe joint 52 shown in FIG. 4, the receiving pipe 54 has a pipe end portion whose diameter is increased to 140.3 mm, an annular protrusion 56 is provided at a position of about 17 mm from the pipe end, and a snap-type lock ring of the annular protrusion is provided. Wear 58. The lock ring 58 may be a round ring or a square ring. On the other hand, the insertion tube 60 is provided with an annular protrusion 62 in the vicinity of the tube end. The elastic gasket 64 is a U-shaped cross section whose cross section is close to an L-shaped rectangle. When the gasket is attached, the inner peripheral surface of the small-diameter portion 66 is brought into contact with the outer peripheral surface of the insertion tube 60 and the inner peripheral surface of the large-diameter portion 68 is brought into contact with the outer peripheral surface of the receiving tube 54 to be crimped.

  On the inner peripheral surface of the half-divided housing 70, an annular groove 72 that fits with the annular protrusion 56 of the receiving pipe 54 and an annular groove 74 with a rectangular cross section that fits with the elastic gasket 64 are formed. For example, in the case of a housing 70 for a tube having a nominal diameter of 100A, the axial width is 72 mm, an annular groove 72 having a width of 12 mm is provided at a position 12 mm from the front end face, and a width of 30 mm is provided at a position 30 mm from the front end face. An annular groove 74 is provided.

  To assemble the pipe joint 52, the elastic gasket 64 and the lock ring 58 are fitted in the insertion pipe 60, and then the insertion pipe is inserted into the pipe end of the receiving pipe 54. Next, the diameter of the lock ring 58 is reduced by utilizing its elasticity, and is inserted between the inner peripheral surface of the receiving tube 54 and the outer peripheral surface of the insertion tube 60 and is expanded in diameter at the position of the annular protrusion 56 of the receiving tube 54. And fix. The elastic gasket 64 is moved to the pipe end of the receiving pipe 54. The tube end of the insertion tube 60 enters about 120 mm from the elastic gasket 64, that is, the receiving tube 54. Next, the semicircular annular portion of the housing 70 is fitted from the outside, and the housing 70 is fastened with two sets of bolts and nuts.

  The pipe joint 76 shown in FIG. 5 is a non-stretchable stainless steel pipe joint connected to a straight pipe connected to the front and back of the deformed pipe or another deformed pipe, and has substantially the same structure as the pipe joint 1 of the first embodiment. . The pipe joint 76 is also applied when diverting the mass-produced pipe joint 1 to a deformed pipe. In the pipe joint 76, wide stopper rings 78 and 78 are tightly fitted on both sides of the annular protrusion 7 of the insertion pipe 5, and the sum of the widths of both rings 78 and 78 and the annular protrusion 7 is the annular groove of the housing 10. Approximately equal to 32 axial widths. The stopper rings 78 and 78 have a half structure in which a plastic coating is applied to stainless steel or carbon steel, and one of the rings is fitted before the annular protrusion 7 is formed.

  A pipe joint 80 shown in FIG. 6 is a non-stretchable pipe connected to a straight pipe connected to the front and back of a deformed pipe or another deformed pipe similarly to the fourth embodiment, and has a structure similar to that of the pipe joint 1 of the first embodiment. is there. Compared with the pipe joint 1 of the first embodiment, the pipe joint 80 has the same structure in the receiving pipe 3, the insertion pipe 5, and the elastic gasket 8, and the housing 82 is shorter. On the inner peripheral surface of the housing 82, an annular groove 28 that closely fits the annular protrusion 6 of the receiving pipe 3, an annular groove 32 that has a rectangular transverse cross section that closely fits the elastic gasket 8, and an annular shape of the insertion pipe 5. An annular groove 84 that fits closely with the protrusion 7 is formed.

DESCRIPTION OF SYMBOLS 1 Pipe fitting for underground bureau 3 Receptacle pipe 5 Insertion pipe 6,7 Annular protrusion 8 Elastic gasket 10 Housing 12 Small diameter part 14 Large diameter part 24 Bolt 26 Nut

Claims (8)

  An underground pipe joint that connects a receiving pipe with an enlarged diameter at the pipe end and an insertion pipe to be inserted into the pipe end of the receiving pipe. The annular protrusion is provided near the pipe end. A stainless steel pipe receiving pipe, a stainless steel pipe insertion pipe with an annular protrusion provided behind the pipe end, an elastic gasket in liquid-tight contact with the receiving pipe and the insertion pipe, and fixing the receiving pipe and the elastic gasket; The elastic gasket has a substantially U-shaped or L-shaped cross section, and the inner peripheral surface of the small diameter portion is the insertion tube, and the inner periphery of the large diameter portion. The inner surface of the housing has an annular groove that fits with the annular protrusion of the receptacle pipe, an annular groove with a rectangular cross section that fits with the elastic gasket, and an annular shape of the insertion pipe. Protrusion and axial direction Stainless steel pipe joint for underground to form the loosely or tightly fitted annular groove.   2. The stainless steel pipe joint according to claim 1, wherein the annular projections provided on the receiving pipe and the insertion pipe are formed by plastic working on the outer surface of the stainless steel pipe or by attaching a ring material by welding.   The stainless steel pipe joint according to claim 1, wherein in the housing, one or more peep holes are provided in an annular groove fitted to an annular projection provided on the receiving pipe and the insertion pipe.   The elastic gasket has a substantially U-shaped cross section, and is connected in a stretchable manner. The inner peripheral surface of the small diameter portion is in contact with the insertion tube, and the inner peripheral surface of the large diameter portion is in contact with the receiving tube. On the inner peripheral surface of the housing, an annular groove closely fitting with the annular protrusion of the receiving pipe, an annular groove having a rectangular cross section closely fitting with the elastic gasket, and an annular protrusion of the insertion pipe slide in the axial direction. The stainless steel pipe joint according to claim 1, wherein a wide annular groove that is movably fitted is formed.   A stainless steel pipe joint that is extendably connected, and an annular protrusion provided on the receiving pipe is a flange-shaped ring member attached to the pipe end, and the elastic gasket has a substantially L-shaped cross section, and has a small diameter portion. The inner peripheral surface of the housing is in contact with the insertion tube and the end surface of the large-diameter portion is in contact with the receiving pipe, and the inner peripheral surface of the housing has an annular groove with a rectangular cross section that fits into the ring material and the elastic gasket of the receiving pipe, The stainless steel pipe joint according to claim 1, wherein the annular protrusion of the insertion tube forms a wide annular groove that is slidably fitted in the axial direction.   A stainless steel pipe joint that is extendably connected to a stainless steel pipe receiving pipe with an annular protrusion near the pipe end, a stainless steel pipe insertion pipe with an annular protrusion near the pipe end, and a receiving pipe and an insertion pipe. It is composed of an elastic gasket that is in liquid-tight contact, and a halved housing that holds the receiving tube and the elastic gasket and holds the insertion tube, and the inner peripheral surface of the housing is in close contact with the annular protrusion of the receiving tube. An annular groove to be fitted and an annular groove having a rectangular cross section closely fitted to the elastic gasket are formed, and a lock ring is fitted and fixed to the inner peripheral side of the annular protrusion of the receiving pipe, and the lock ring is fixed to the pipe. Underground stainless steel pipe fitting that prevents the insertion pipe from coming out by abutting against the annular projection of the insertion pipe when the joint is extended.   A non-stretchable stainless steel pipe joint that connects to a deformed pipe, and a rectangular groove that fits tightly with an elastic groove and an annular groove that fits closely with the annular projection of the receiving pipe on the inner peripheral surface of the short housing 2. The stainless steel pipe joint according to claim 1, wherein an annular groove having a transverse cross section and an annular groove closely fitting with the annular protrusion of the insertion tube are formed.   A non-stretchable stainless steel pipe joint that connects to a deformed pipe. The housing has an inner circumferential surface with an annular groove that fits closely with the annular projection of the receiving pipe, and a rectangular cross section that fits tightly with the elastic gasket. The stainless steel according to claim 1, wherein an annular groove and a wide annular groove into which the annular projection of the insertion tube is fitted are formed, and a stopper ring is closely fitted on both sides of the annular projection of the insertion tube in the wide annular groove. Steel pipe fitting.

Images