JP2011256939A - Branch joint for pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a branch joint capable of preventing occurrence of breakage by applying excessive stress even for a degraded pipe relatively low in strength such as a gray cast iron pipe, and surely tightly fitting the pipe to the branch joint itself.SOLUTION: A tapered female thread screwing to a tapered male screw of a branch pipe 5 is threaded on one end-side inner peripheral surface of a joint body 2, and a parallel male screw screwing to a parallel female screw of a main pipe 4 is threaded on the other end-side outer peripheral surface thereof. An O-ring 6a for keeping airtightness with the undersurface of a fastening part 2b of the joint body 2 is mounted around an insertion opening part 3f of a saddle member 3. An O-ring 6b for keeping airtightness with an outer peripheral surface of the main pipe 4 is mounted to the lower surface thereof.

Description

  The present invention relates to a pipe having a relatively weak strength such as a gray cast iron pipe or a steel pipe having a thin pipe thickness and incapable of sufficient gas sealing with a taper screw, and particularly to a pipe branch joint used when branching out from a pipe. .

Conventionally, as a fixing method of a pipe branch joint used when branching out from a pipe, there are known a method of attaching a branch joint by screwing into a drilled hole drilled in a main pipe or a method using a split sleeve.
Of these, in the drilling hole method, a pipe is drilled with a taper screw, a taper screw that is a female thread is cut into the drilled part, and this is meshed with a taper screw of a male thread on the branch joint side to connect the pipe and the branch pipe. It is common to fix. By using the taper screw, when the joint is connected to the pipe, the tightness between the pipe is enhanced, and the sealing performance is secured so that the fluid such as gas does not leak.
However, when a pipe branch joint with such a “tapered screw” is attached to the pipe, the diameter of the drilled part is increased by the taper screw, so the threaded part of the pipe cannot withstand the stress, and the branch joint Screwing in the tube may cause cracks in the tube. Such cracks may not be easily confirmed visually, and as a result of being subjected to stress for a long time after the branch joint is mounted, such cracks may cause large breakage. In particular, in aging cast iron pipes and gray cast iron pipes, ensuring safety and ensuring safety by preventing such cracks have become important.

In order to prevent such cracking, the O-ring seal has been intensively developed to reinforce it with a member that covers the pipe circumferential direction, such as a split sleeve, saddle, clamp, etc., so that a predetermined sealing performance can be secured. Has been done. Regarding the pipe branch joint, a method of fixing the pipe without causing excessive strain is disclosed (for example, Patent Document 1).
The split sleeve is disclosed in Patent Document 2. In the split sleeve system 100, as shown in FIG. 11, two sleeve pieces 101a and 101b are sandwiched from the upper surface and the lower surface of the main tube 102 and fixed with bolts and nuts 106. Sealing is performed with an O-ring 105 while reinforcing the stress intensity, and the branch pipe 103 is connected to the branch portion 104 provided on the sleeve piece 101a.

JP 2000-035175 A JP 2009-28785A

According to the split sleeve method, the branch pipe can be securely connected to the pipe, and even when the branch pipe is connected to the pipe having low strength, the pipe is perforated by bending stress acting locally on the pipe. It is possible to reliably prevent adverse effects.
However, a large member is required, the amount of excavation in the construction of the branch joint is increased, and the cost is increased.

  The present invention provides a branch joint capable of securely bringing a pipe and a branch joint into close contact with each other without causing excessive stress to cause damage to a cast iron pipe having a relatively low mechanical strength. It is.

A first invention for achieving the above-described object is a pipe branch joint for connecting a branch pipe in a main pipe path, a joint main body screwed to the main pipe and the branch pipe, a joint main body, A saddle member interposed between the main pipe, a first O-ring and a second O-ring which are attached to the saddle member and maintain airtightness between the saddle member and the joint body or the main pipe, The joint body is formed in a substantially cylindrical shape, and has a tapered female thread portion for connection to the branch pipe on the inner peripheral surface on one end side, and a main pipe on the outer peripheral surface on the other end. A parallel male thread portion, and a tightening portion that protrudes to the center portion and tightly attaches the saddle member to the main pipe, and the saddle member is attached to the first O-ring on the joint surface with the tightening portion. A first O-ring groove for mounting, and a second O-ring groove for mounting a second O-ring on the joint surface with the main pipe, They comprise a tube branch joint, characterized by comprising.
According to the present invention, a branch joint can be connected to a cast iron pipe or the like having a relatively low mechanical strength without applying excessive stress and causing damage.

According to a second invention, in the above invention, the second O-ring groove is provided on a joint surface with the outer surface of the main pipe, and the first O-ring groove is horizontally joined with the tightening portion of the joint body. It is provided on the surface.
According to a third invention, in each of the above inventions, the second O-ring groove is provided on a joint surface with the outer surface of the main pipe, and the first O-ring groove is perpendicular to the tightening portion of the joint body. It is provided on the joint surface.
The arrangement of the O-ring maintains the same sealing performance as that of a taper screw even with a parallel screw.

According to a fourth invention, in each of the above inventions, the diameter of the second O-ring groove is configured to be larger than the diameter of the first O-ring groove.
Since the surface in contact with the tube is curved and the surface of the tube has fine irregularities, a larger O-ring prevents leakage.

The fifth invention is characterized in that a corner portion for hanging the wrench is provided on the outer periphery of the tightening portion.
By providing a wrench-shaped protrusion on the outer periphery of the tightening portion, it is possible to provide a branch joint for a pipe having a simple structure without requiring a separate member for tightening the saddle member.

According to a sixth aspect of the invention, the saddle member has a smooth joint surface with the joint body.
The saddle member can be easily attached to the pipe branch joint, and an O-ring groove can be formed on the smooth surface to improve the airtightness of the saddle member and the pipe branch joint.

According to a seventh aspect of the invention, the tightening portion includes a parallel male screw portion provided on the outer peripheral surface of the joint body, and a nut member having a parallel female screw portion that can be joined to the parallel male screw portion. And
Instead of an integral structure in which a wrench flat portion is formed in the tightening portion, the tightening portion can also be configured as a mounting member for a pipe branch joint, and a nut member can be appropriately mounted.

According to an eighth aspect of the present invention, the inner peripheral surface of the joint body has an inner diameter (R1) at a joint side end position with a main pipe, and a branch pipe at a joint side end position with the branch pipe in a branch pipe joined state. The inner diameter (R2) is configured to have substantially the same length.
According to the present invention, it is possible to make the inner diameter of the branch pipe and the mounting hole the same, and it is possible to prevent fluid pressure loss at the joint portion.

In a ninth aspect of the invention, the joint body is configured such that an outer diameter of the tightening portion is larger than an outer diameter of the male parallel thread portion.
According to the present invention, the contact area between the saddle member and the nut member can be increased, and the sealing performance against leakage can be enhanced.

  According to the branch joint for pipes of the present invention, a conventional taper screw is used for a connection portion with a search or a plug, and a parallel screw is used for a connection portion with a pipe such as a cast iron pipe having a relatively low mechanical strength. ing. For this reason, when fitting the branch joint for pipes to the pipe, there is an effect that even if the branch joint for pipes is tightened, excessive stress is applied and the pipe is not damaged.

Further, the pipe and the pipe branch joint are in close contact with each other through the saddle member, but the saddle member has an O-ring groove, and it is possible to securely bring the pipe and the branch joint into close contact with each other with the O-ring.
In addition, since the structure does not require a large member such as a split sleeve, the amount of excavation in the construction of the branch joint can be reduced, and the installation cost can be greatly reduced.

  In particular, in the seventh invention, since the fastening portion is configured in a shape suitable for hanging with a wrench, the number of branch joint members can be reduced, and the cost of the pipe branch joint can also be reduced.

It is an expanded view of the branch joint 1 for pipes concerning 1st embodiment. It is a figure which shows the detailed structure of the coupling main body 2 for pipes. The figure which shows the detailed structure of the saddle member 3. FIG. It is sectional drawing of the branch pipe 5 attachment state of the branch joint 1 for pipes. It is the figure which rotated FIG. 4 90 degree | times with respect to the main axis | shaft. It is a figure which shows the form of O-ring 6b in the saddle member 3 attachment state. FIG. 7 is a view obtained by rotating FIG. 6 by 90 degrees with respect to the main shaft. It is a figure which shows the cross-sectional positional relationship of each component in the branch joint 1 joining state for pipes. It is a figure which shows the joining state of the branch joint 20 for pipes concerning 2nd embodiment. It is a figure which shows the joining state of the branch joint 30 for pipes concerning 3rd embodiment. It is a figure which shows the construction method by the conventional split sleeve system.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.
<First embodiment>
With reference to FIGS. 1 to 3, the pipe branch joint 1 according to the present embodiment is disposed on the lower side of the joint main body 2 that connects the main pipe 4 and the branch pipe 5 and is kept airtight. The saddle member 3 is a main component.
The joint body 2 is formed in a substantially cylindrical shape, and includes a branch pipe connecting part 2a on one end side and a main pipe connecting part 2c on the other end side with a central fastening part 2b interposed therebetween. A tapered female thread 2d that can be screwed with the tapered male thread 5a of the branch pipe 5 is cut on the inner peripheral surface of the branch pipe connecting portion 2a. A parallel male screw 2e that can be screwed with the parallel female screw 4a of the main pipe 4 is cut on the outer peripheral surface of the main pipe connecting portion 2c. A vertical smoothing portion 2f is provided above the parallel male screw 2e. The outer peripheral surface of the tightening portion 2b is formed in a hexagonal surface to enable wrenching.

The saddle member 3 is formed in a bowl shape so that the lower side surface 3e is in close contact with the outer peripheral surface of the main pipe 4, and an insertion port portion 3f that allows the main pipe connection portion 2c of the joint body 2 to be inserted in the center, and the upper side surface And a base portion 3a formed in a flat shape so as to be in close contact with the lower side surface 2g of the tightening portion 2b. An O-ring 6a (corresponding to the first O-ring in the claims) can be mounted around the insertion opening 3f of the pedestal 3a to maintain airtightness with the lower surface of the tightening portion 2b of the joint body 2. An O-ring groove (corresponding to a first O-ring groove in claims) 3c is provided in a circumferential shape.
4 and 5, the lower surface 3e of the saddle member 3 has an O-ring 6b for maintaining airtightness with the outer peripheral surface of the main pipe 4 (corresponding to the second O-ring in the claims). Is provided with an O-ring groove (corresponding to a second O-ring groove in claims) 3d.
Referring to FIGS. 6 and 7, the O-ring 6 b mounted in the O-ring groove 3 d has a shape that tightly adheres to the outer surface of the main pipe 4 to ensure airtightness when the joint body 2 is fixed.

The pipe branch joint 1 is configured as described above. Next, a method of connecting the branch pipe 5 to the main pipe 4 using the branch joint 1 will be described.
First, the main pipe 4 embedded in the ground is exposed, and the mounting hole 4a is drilled from the outside. Next, the lower surface 3 e of the saddle member 3 is placed on the outer peripheral surface of the main pipe 4 by aligning the mounting hole 4 a with the central axis of the insertion port 3 f of the saddle member 3. In this state, the joint body 2 is inserted into the insertion port 3f of the saddle member 3, and the parallel male screw 2e of the joint body 2 is screwed into the parallel female screw 2c of the main pipe 4 and fixed with a dedicated wrench. After the joint body 2 and the main pipe 4 are joined and fixed, the taper male screw 5a of the branch pipe 5 is screwed into the taper female thread 2d provided on the inner peripheral surface of the branch pipe connecting portion 2a of the joint body 2 to branch. The pipe 5 is joined and fixed to the joint body 2.

Referring to FIG. 8, the cross-sectional positional relationship between the components in the joined state is as follows. That is, in the figure, the distance (inner diameter) from the central axis of the branch pipe 5 at the same height position as the upper end of the joint body 2, that is, the inner diameter R2 at the A position of the branch pipe 5 and the B position of the joint body 2 The inner diameter R1 is substantially the same. Thereby, the pressure loss by the branch joint connection for pipes can be prevented.
Further, the distance (outer diameter) H2 from the central axis to the tip of the tightening portion 2b is configured to be larger than the outer diameter H1 to the top of the thread of the parallel male screw 2e. Due to the difference in the outer diameter, the fastening portion 2b can be easily fastened to the saddle member 3.

  In this embodiment (the same applies to the embodiments described later), in the case of a gas pipe, a low pressure (less than 0.1 MPa) or an intermediate pressure B (0.1 MPa or more and less than 0.3 MPa) is applied to the pipe branch joint. Assume a pipe to be connected. The present invention is effective for cast iron pipes, but can also be applied to steel pipes and other pipes. In addition, the diameter of the pipe is about 100A to 150A, especially 50A and 75A for mounting holes of ductile pipe (100A to 300A), and about 25A to 75A for mounting holes of steel pipe (100A to 300A). Can be used.

Furthermore, in the case of a gray cast iron pipe (100A to 150A), the thickness of the pipe is about 9 to 11 mm, and in the case of the steel pipe 100A or the gray cast iron pipe 300A, the pipe thickness is about 4.5 to 14 mm. Application is desirable.
Further, in the case of a gas pipe, according to JIS B 0203-1999, a taper male thread can be implemented with a thread or a reference diameter in the range of R1 to R3. Pile and reference diameter are desirable. For the parallel screw, it is desirable that the screw thread and the reference diameter are in the same range as the taper screw.

  Normally, when a taper screw is used for the mounting hole, it is conceivable that the pipe will not endure the stress at the time of tightening the screw, and the pipe will be cracked. However, according to the present embodiment, the parallel female screw 4a is cut. Therefore, an excessive stress is not applied to the pipe. Further, since the pedestal 3a of the saddle member 3 is a smooth surface, the adhesion with the joint body 2 is enhanced.

<Second Embodiment>
Next, another embodiment of the present invention will be described with reference to FIG. The difference of the configuration of the branch joint for pipe 20 according to the present embodiment from the above-described branch joint for pipe 1 is the configuration of the saddle member. That is, in the pipe branch joint 1 described above, the O-ring groove 3c for maintaining airtightness with the joint body 2 is provided in the pedestal portion 3a on the upper side of the saddle member 3, whereas the saddle member 3 and the joint The vertical joint surface of the main body 2 is composed of a vertical smooth surface 2f. In the pipe branch joint 20, an O-ring groove 21 a for maintaining airtightness with the smooth surface 2 f of the joint body 2 is provided on the inner peripheral surface of the saddle member 21. Since the other configuration is the same as that of the branch joint 1, redundant description is omitted.
With this configuration, in the pipe branch joint 20, the saddle member 21 is pressure-bonded to the main pipe 4 by tightening the fastening portion 2b of the joint body 2, and the air tightness between the saddle member 21 and the main pipe 4 is ensured by the O-ring 6b. Is done. Further, the O-ring 6a fitted in the O-ring groove 22a ensures the airtightness of the main pipe 4 and the branch joint 2.

<Third embodiment>
Furthermore, another embodiment of the present invention will be described with reference to FIG. The configuration of the pipe branch joint 30 according to the present embodiment is different from the above-described pipe branch joint 20 in the configuration of the joint body tightening portion and the configuration of the saddle member.
That is, in the pipe branch joint 20, the tightening portion 2 b is formed integrally with the joint body 2, whereas the pipe branch joint 30 includes a nut member 33 independent of the joint body 31. A parallel female screw 33a is cut on the inner side surface of the nut member 33, while a parallel male screw 31a screwed with the female screw 33a is cut at the outer peripheral center portion of the joint body 31 corresponding thereto.
Further, in the above-described embodiment, the pedestal portion of the saddle member 21 is uniformly formed of a smooth surface. On the other hand, the saddle member 32 of the present embodiment protrudes in a ring shape on the upper surface and is below the nut member 33. A pedestal 32a that is in close contact with the side surface is provided. Note that the vertical joint surface between the saddle member 32 and the joint body 31 is formed of a vertical smooth surface 31b, which is the same as the vertical smooth surface 2f in the pipe branch joint 20.
The other configuration is the same as that of the branch joint 1, so the duplicate description is omitted.

Construction of the branch joint 30 for pipes is performed according to the following procedure. After temporarily fixing the joint body 2 to the main pipe 4 with the parallel screw 2c, the nut member 33 is fixed while confirming that the O-ring 6a is attached to the O-ring groove 32b and the O-ring 6b is attached to the O-ring groove 32c. Tightening in the direction of the main pipe 4 ensures airtightness between the joint body 2 and the main pipe 4. By tightening the saddle member 32 with the nut member 33, it is possible to improve the adhesion with the main pipe 4 while being a parallel screw.
Further, since the tightening portion of the nut member 33 is not a taper screw but a parallel screw, the saddle member 32 can be pressed against the main pipe 4 with sufficient strength to achieve a gas seal with an O-ring, Unreasonable stress is not applied to the joint body 31.

The embodiments of the present invention have been described in detail with reference to the drawings. However, the configuration of the present invention is not limited to these embodiments, and all modifications within the scope of the present invention are not limited thereto. Is included.

1, 20, 30... Pipe branch joint 2, 31... Joint body 2a ... Branch pipe connection part 2b ... Tightening part 2c ... Main pipe connection part 2e ... Smooth surface 2f ... vertical smoothing part 2g ... lower surface 3, 21, 32 ... saddle members 3a, 32a ... pedestal parts 3c, 3d, 21a, 21b, 32b, 32c ... O-ring groove 3f ... Insert port 3e ... Lower side 4 ... Main pipe 5 ... Branch pipe 4a ... Mounting holes 6a, 6b ... O-ring 33 ... Nut member

Claims (9)

A pipe branch joint for connecting a branch pipe in the main pipe path,
A joint body threadedly connected to the main pipe and the branch pipe;
A saddle member interposed between the joint body and the main pipe,
A first O-ring and a second O-ring, which are attached to the saddle member, and maintain the airtightness between the saddle member and the joint body or the main pipe;
Comprising
The joint body is formed in a substantially cylindrical shape,
A taper female screw portion for connection to the branch pipe on the inner peripheral surface on one end side, and a parallel male screw portion for connection to the main pipe on the outer peripheral surface on the other end;
A projecting portion at the center, and a tightening portion for closely attaching the saddle member to the main pipe,
The saddle member is
A first O-ring groove for mounting the first O-ring on the joint surface with the tightening portion;
A second O-ring groove for mounting the second O-ring on the joint surface with the main pipe,
A branch joint for pipes characterized by comprising:   The second O-ring groove is provided on a joint surface with an outer surface of a main pipe, and the first O-ring groove is provided on a horizontal joint surface with the tightening portion of the joint body. Item 2. A pipe branch joint according to Item 1.   The second O-ring groove is provided in a joint surface with an outer surface of a main pipe, and the first O-ring groove is provided in a vertical joint surface with the tightening portion of the joint body. Item 3. A pipe branch joint according to Item 1 or 2.   The branch joint for pipe according to any one of claims 1 to 3, wherein a diameter of the second O-ring groove is configured to be larger than a diameter of the first O-ring groove.   The branch joint for pipes according to any one of claims 1 to 4, wherein a corner portion for wrenching is provided on an outer periphery of the tightening portion.   The pipe branch joint according to claim 1, wherein the saddle member has a smooth joint surface with the joint body.   2. The tightening portion includes a parallel male screw portion provided on an outer peripheral surface of the joint body, and a nut member having a parallel female screw portion that can be joined to the parallel male screw portion. The branch joint for pipes of thru | or 6.   The inner peripheral surface of the joint main body has an inner diameter (R1) at a joint side end position with the main pipe, and an inner diameter (R2) of the branch pipe at a joint side end position with the branch pipe in the branch pipe joined state, The pipe branch joint according to any one of claims 1 to 7, wherein the pipes have substantially the same length.   The pipe joint according to any one of claims 1 to 8, wherein the joint body is configured such that an outer diameter of the tightening portion is larger than an outer diameter of the male parallel thread portion.

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