JP2007085432A - Joint for branching same-diameter active pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint for branching a same-diameter active pipe in a simple form having excellent sealing properties. <P>SOLUTION: The joint for branching a same-diameter active pipe is equipped with: an upper main body 2 with a branch port 22 which is connected with a branch pipe; and a lower main body 3 fastened at an outer circumference surface of an existing pipe 10 having an opening 11 communicating with the branch port 22 as well as the main body 2. The upper main body 2 has: a pair of first protruding parts 23 extending along a pipe axial direction of the existing pipe 10 across the branch port 22, a ring-shape sealing gutter 231 where a ring-shape packing 5 is supported is formed between the first protruding parts 23 and the existing pipe 10, and the ring-shape sealing gutter 231 protrudes to a middle part 23a of the first protruding parts 23. The lower main body 3 has a pair of second protruding parts 33 facing against the first protruding parts 23. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a live pipe branch joint having the same diameter used to take out a branch pipe having the same diameter as an existing pipe from which gas flows, for example.

  In the gas piping, gas is supplied at a predetermined pressure according to the supply amount of fuel gas (for example, city gas or natural gas), the size of the supply area, and the like. For example, in a small-scale gas establishment with a small gas supply amount and a narrow gas supply area, the low-pressure supply (gas pressure is less than 0.098 MPa) has the advantage of a simple supply system and no pumping costs. Is adopted. In various gas pipes including this low pressure supply, in order to take out a branch pipe from a main pipe (for example, a resin-coated steel pipe, also referred to as a main pipe) buried in the ground and in which gas flows, A pair of saddle type joints including a joint body (split joint) is attached to the main pipe, a branch hole is drilled in the main pipe with a cutter attached to the branch section provided in one joint, and then the branch pipe is connected to the branch section. To be done.

  For example, in Patent Document 1, a cylindrical wall for connecting to a branch pipe is provided on one of a pair of split joints that are fastened and connected to a fluid pipe in an externally fitted state, and a passage in the cylindrical wall is provided. A first elastic seal member is provided on the split joint so as to be in close contact with the split joint and the fluid pipe, and a thread-like member for pressing the tip of the fluid pipe is threadably engaged with at least one of the split joints. And a pair of second elastic seal members are provided on both sides of the fluid pipe in the axial direction of the first elastic seal member so as to be in close contact with the entire circumference of the fluid pipe, the first elastic seal member and the second elastic seal member. A branch extraction joint is described in which a tip of a screw-like member is disposed between the elastic seal member. According to this branch extraction joint, the main pipe is press-contacted by the threaded member, so that the split joint is prevented from being displaced in the axial direction and the circumferential direction with respect to the main pipe. Since the gap is sealed with the first elastic seal member and the pair of second elastic seal members, and a portion where air and water do not enter is formed there, there is an advantage that oxidative corrosion at the tip of the screw-like member can be suppressed. .

  In recent years, with an increase in gas demand, it is required to connect a branch pipe having the same size as the main pipe to the branch portion and perform branch extraction with a large flow rate (same diameter active pipe branch extraction). For example, in Patent Document 2, a pair of first and second split joints are included in a part of an axial direction of a main pipe such as an iron pipe or a cast iron pipe, a branch pipe is connected to a split connection port of a second split joint, Set a hole saw in the drilling operation port of the second split joint, and lower the hole saw parallel to the vertical neutral surface while rotating it at a position eccentric from the vertical neutral surface of the main tube. Perforation is described.

JP-B-2-39678 (pages 2 and 3, FIGS. 1 and 2) Japanese Patent Laid-Open No. 2001-132887 (pages 4-5, FIGS. 1-7)

  According to the above-mentioned joint for splitting live pipes with the same diameter, a special dedicated tool (hole saw) is required because a hole is drilled in the side surface of the existing pipe in order to secure a large flow rate, so that the tool can be incorporated. However, there is a problem that the joint structure becomes complicated. In addition, a sealing material is interposed between the contact surfaces of the inner surface of the main pipe connection port of the second split joint and a part of the circumference of the main pipe, and a mechanism for bringing the sealing material into close contact with the outer peripheral surface of the main pipe. Therefore, it is difficult to obtain a sufficient sealing property. Further, this kind of joint is formed of cast iron, for example, and its surface is subjected to anticorrosion treatment (for example, hot dip galvanizing) to further improve corrosion resistance, and the entire joint is covered with anticorrosion tape after pipe construction. However, since the joint has a complicated shape having a branch port, not all surfaces can be covered, and corrosion resistance is not sufficient.

  An object of the present invention is to solve the above-mentioned problems and to provide a joint for splitting an active pipe having the same diameter and excellent sealing performance.

  Another object of the present invention is to solve the above-mentioned problems and to provide a joint for branching the same diameter active tube having a simple shape and excellent sealing properties and corrosion resistance.

  In order to achieve the above-mentioned object, the same-diameter live pipe branch joint of the present invention comprises an upper body having a branch port to which a branch pipe is connected and an existing pipe having an opening communicating with the branch port together with the upper body. A lower main body fastened to the outer peripheral surface, the upper main body having a pair of first protrusions extending along the tube axis direction of the existing pipe so as to sandwich the branch port, An annular seal groove for holding an annular packing is formed between the projecting portion and the existing pipe, and the annular seal groove protrudes from an intermediate portion of the first projecting portion. It has a pair of 2nd protrusion part facing the said 1st protrusion part, It is characterized by the above-mentioned.

  In the present invention, an elastic body may be sandwiched between the first protrusion and the second protrusion.

  In the present invention, the second projecting portion is in contact with the first projecting portion and the annular packing, and the lower body is provided with a pressure contact member that presses the existing pipe against the upper body. be able to.

  In the present invention, the upper main body and the lower main body are preferably made of black-heart malleable cast iron and have a film made of hot dip galvanized and a film made of cationic electrodeposition coating formed thereon.

  According to the present invention, since the annular seal groove protrudes from the intermediate portion of the first projecting portion, the annular packing is in close contact with the existing pipe and the lower main body over the entire circumference, and has excellent sealing properties. Can be obtained. In particular, the sealing performance is further improved by bringing the annular packing attached to the upper body and the first protrusion of the upper body into pressure contact with the second protrusion of the lower body via an elastic body. Therefore, even if a large external force is applied to the gas piping including the joint due to changes in the ground such as road loads, impacts, land subsidence, and earthquakes, the joint body is effectively prevented from slipping and leaking gas. Can do.

  According to the present invention, since the elastic body is sandwiched and tightened between the first projecting portion of the upper body and the second projecting portion of the lower body, it is excellent even if the outer diameter is somewhat large or small. The sealing property can be obtained. That is, the outer diameter of the existing pipe can be allowed by the amount of deformation of the elastic body.

  According to the present invention, even if the second projecting portion is configured to contact the first projecting portion and the annular packing, the annular packing attached to the upper body is a pressure contact member provided on the lower body. By adopting a structure that presses and presses against the surface of an existing pipe, it is possible to obtain excellent sealing properties as described above.

  According to the present invention, the upper main body and the lower joint main body can have excellent corrosion resistance by having a film made of hot-dip galvanized and a film made of cationic electrodeposition coating formed thereon.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view in which a part of a joint for live-tube branching with the same diameter according to the first embodiment of the present invention is cut out, FIG. 2 is a half sectional view thereof, and FIG. FIG. 4 is a sectional view taken along the line AA in FIG. 3, FIG. 5 is a sectional view taken along the line BB in FIG. 3, and FIG. 6 is a sectional view of the lower member from the mating surface with the upper member. It is a top view at the time of seeing.

  As shown in FIG. 1 and FIG. 2, the same-diameter active pipe branching joint 1 includes an upper body 2 mounted on an upper portion of a gas conduit (hereinafter referred to as an existing pipe) 10 embedded in the ground, The lower body 3 is attached to the lower part, and these bodies are integrally coupled by fastening a plurality of (four in the figure) fastening bolts (for example, hexagon socket head cap bolts) 4. The existing pipe 10 is, for example, a coated steel pipe (single-layer coated steel pipe) in which the outer surface of a steel pipe made of carbon steel is coated with a single layer of polyethylene, or a coating in which the outer surface of the steel pipe is coated with polyethylene via an adhesive layer (modified polyethylene). A steel pipe (two-layer coated steel pipe) can be used (see JIS G3452). The hexagon socket head cap bolt 4 is preferably formed of a metal material having excellent corrosion resistance such as austenitic stainless steel (for example, SUS304) in order to prevent corrosion.

  Referring also to FIG. 3, the upper body 2 has a saddle shape, a rectangular base portion 21 having bolt insertion holes 211 at each corner portion, and a branch port 22 communicating with the opening 11 drilled in the existing pipe 10. And a pair of first protrusions 23 having a wedge-shaped cross section extending in the tube axis direction of the existing pipe 10 (see FIG. 1) so as to sandwich the opening 11 on the surface facing the lower body 3. An annular (for example, elliptical) seal groove 231 is provided between the first protrusions 23 in the vicinity of the opening 11, and the annular packing 5 is attached thereto. As this packing, for example, an O-ring made of nitrile rubber (NBR) having excellent oil resistance can be used. Further, the annular seal groove 231 may have a perfect circle shape, but may have an elliptical shape as shown in FIG. When the seal groove 231 has an elliptical shape, a part of the arc along the major axis direction is formed so as to protrude into the intermediate portion 23a (the region indicated by L in FIG. 3) of the first protrusion 23. That is, as shown in FIG. 4, the first projecting portion 23 has a mountain shape in which both end portions extend to a semicircular arc portion that receives the existing pipe, whereas the intermediate portion 23 a of the first projecting portion 23 is As shown in FIG. 5, it becomes a mountain shape which has a lower height than both side parts.

  Referring also to FIG. 6, the lower main body 3 has a saddle shape, a rectangular base portion 31 having a tap hole 311 into which the fastening bolt 4 is screwed into each corner portion, and a substantially semicircle on the lower side of the existing pipe 10. The circular arc part 32 which receives a surrounding surface, and a pair of 2nd protrusion part 33 which has a wedge-shaped cross section extended along the pipe-axis direction of the existing pipe 10 in the surface on the side facing the upper main body 2.

The upper body 2 and the lower body 3 are made of, for example, black core malleable cast iron (JIS) so as not to break when the tightening bolt 4 is tightened with a predetermined tightening torque (for example, 40 to 50 N · m). G 5702: FCMB material), and the surface thereof is subjected to anticorrosion treatment in order to impart anticorrosion properties. The anticorrosion treatment can be carried out, for example, by performing electrodeposition coating after performing hot dipping. In hot dipping, the joint body 2 or 3 is immersed in molten metal for a predetermined time to form a metal film on the surface. The corrosion rate of the metal film is higher than that of steel, but is generated on the metal surface. Corrosion resistance can be improved by reducing the corrosion rate due to the relatively dense oxide film and corrosion products. For example, in the present invention, hot dip galvanization is preferable, but in this hot dip galvanization, dense corrosion products formed on the zinc surface {ZnO, Zn (OH) ₂ , ZnCO ₃ , Zn (OH) _3, etc. }, The corrosion resistance is improved by the weather resistance, corrosion resistance, and the protective action of zinc against iron when the iron base is locally exposed.

  Electrodeposition is a method in which a coating is applied to the surface of an object by direct current in a water-based or emulsion resin coating tank, and a constant film thickness with little moisture is obtained. In addition, it has advantages such as uniform adhesion and good adhesion, and since the main body and the bolt are electrically insulated, electrical corrosion due to contact between different metals can be prevented. Among the electrodeposition coatings, cationic electrodeposition using the object to be coated as a cathode is suitable, and it is preferable to use an acrylic resin-based paint from the viewpoint of rust prevention.

  As shown in FIGS. 1 and 2, the upper main body 2 and the lower main body 3 holding the annular packing 5 include a tapered surface 232 of the first projecting portion 23 and a tapered surface 331 of the second projecting portion 33 of the lower body 3. In between, the sheet-like elastic body 6 is attached to the existing pipe 10 in a sandwiched state. The sheet-like elastic body 6 can be formed of, for example, an olefin rubber such as ethylene-propylene rubber (EPDM) having excellent heat resistance.

  According to the above joint structure, the upper main body 2 has a shape in which a part of the first projecting portion 23 is notched, so that the annular packing 5 and the first projecting portion 23a are tapered surfaces of the second projecting portion 33. Since it faces 331, the adhesion between the two is improved. In particular, since the annular packing 5 and the first projecting portion 23 of the upper body 2 and the second projecting portion 33 of the lower body 3 are in contact with each other through the elastic body 6, the tightening bolt 4 is fastened to the upper side. When the main body 2 and the lower main body 3 are joined, the adhesion is further improved, and an excellent sealing property can be obtained.

The present invention is not limited to the above structure, and for example, the following modifications are possible.
FIG. 7 is a perspective view in which a part of the same-diameter active pipe branch joint according to the second embodiment of the present invention is cut away, FIG. 8 is a half sectional view thereof, and FIG. 9 is a plan view of a lower body. 1 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 7 and 8, the same-diameter active pipe branching joint 1 has a pair of first protrusions 23, holds the annular packing 5, and is attached to the semicircular surface of the existing pipe 10. The upper main body 2 and the lower main body 3 having a pair of second projecting portions 33 and attached to the remaining circumferential surface of the existing pipe 10 are provided. Further, the upper body 2 and the lower body 3 are fixed to the existing pipe 10 by a plurality of (four in the drawing) tightening bolts 4 that pass through the base portion 21 and are screwed to the base portion 31. This is the same as that of the first embodiment. The upper main body 2 is the same as that shown in FIG. 3, but the lower main body 3 has two tap holes 34 into which the pressure contact members (push bolts) 7 are screwed into the arc portions 32 as shown in FIG. 9. It differs from that shown in FIG. 4 in that it is formed.

  In the present embodiment, since the taper surface 232 of the first protrusion 23 of the upper body 2 and the taper surface 331 of the second protrusion 33 of the lower body 3 are in direct contact with each other, sufficient sealing performance is ensured. Therefore, the upper body 3 is firmly attached to the existing pipe 10 by screwing the push bolt 7 into the lower body 3. The pressure contact member is not limited to the push bolt 7 screwed into the lower body, but may be any structure provided on the lower body 3 and pressing the existing pipe 10 against the upper body 2.

It is a perspective view of the joint for same diameter active pipe branching concerning the 1st Embodiment of this invention. FIG. 2 is a half sectional view of the same-diameter live pipe branch joint of FIG. 1. It is a top view at the time of seeing an upper body from the mating surface with a lower body. FIG. 4 is a sectional view taken along line AA in FIG. 3. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a top view at the time of seeing a lower main body from the mating surface with an upper main body. It is a perspective view of the joint for same diameter active pipe branching concerning the 2nd Embodiment of this invention. FIG. 6 is a half sectional view of the same-diameter live pipe branch joint of FIG. 5. It is a top view at the time of seeing a lower main body from the mating surface with an upper main body.

Explanation of symbols

1: Same diameter active pipe branch joint,
2: upper main body, 21: base portion, 22: branch port, 23: first projecting portion, 23a: intermediate portion,
231: Seal groove, 232: Tapered surface 3: Lower main body, 31: Base portion, 311: Tapped hole, 32: Arc portion, 33: Second projecting portion, 331: Tapered surface, 34: Tap hole 4: Tightening bolt 5: annular packing, 6: elastic body, 7: pressure contact member (push bolt)
10: Existing pipe, 11: Opening

Claims (4)

An upper body having a branch port to which a branch pipe is connected; and a lower body fastened to an outer peripheral surface of an existing pipe having an opening communicating with the branch port together with the upper body, the upper body having the branch An annular seal groove having a pair of first protrusions extending along the tube axis direction of the existing pipe so as to sandwich the mouth, and an annular packing is held between the first protrusion and the existing pipe The annular seal groove protrudes from an intermediate portion of the first protrusion, and the lower main body has a pair of second protrusions facing the first protrusion. Same diameter live pipe branch joint. The joint for live pipe branching with the same diameter according to claim 1, wherein an elastic body is sandwiched between the first projecting portion and the second projecting portion. The second projecting portion is in contact with the first projecting portion and the annular packing, and the lower main body is provided with a pressure contact member that presses the existing pipe against the upper main body. 1. The joint for branching the same diameter active pipe according to 1. The upper main body and the lower main body are formed of black core malleable cast iron, and the surface thereof has a film made of hot dip galvanized and a film made of cationic electrodeposition coating formed thereon. Item 4. The joint for branching the same diameter active pipe according to any one of Items 1 to 3.

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