JPH06221479A - Pipe joint structure - Google Patents

Abstract

PURPOSE:To prevent coming-out of packing under both internal and external pressure by making up a packing with its heel and valve portions and holding the heel portion between the packing contact of a press ring member and the rear end face of a large-diameter pipe. CONSTITUTION:A bolt insertion hole 19 in a press ring 5 and a bolt insertion hole 9 in a flange 6 are brought together in phase, so that the press ring is attached to the end portion of a sleeve 7. The stepped portion at front of a packing 3 makes slight contact with the end portion 7c of the sleeve 7. In this state, a nut 4b of a tightening means 4 is tightened in rotation, so that the press ring 5 advances toward the sleeve 7 in large tightening force. The heel portion 12 of the packing 3 is thus strongly held between the packing holding face 20 of the press ring 5 and the sleeve 7. Then, an insertion pipe 2 is inserted into the sleeve through the packing 3. In this case, the packing 3 does not come out because the heel portion 12 of the packing 3 is firmly held with the press ring 5.

Description

Detailed Description of the Invention

A. OBJECT OF THE INVENTION (1) Industrial field of application The present invention relates to a pipe joint structure for connecting fluid pipes to each other in a piping system, and more specifically, to a flexible expansion / contraction pipe used for expansion / contraction and bending. Regarding the pipe joint structure. In particular, the present invention relates to what is suitable for being applied to a so-called expansion / contraction flexible joint pipe interposed in a fluid pipe to be connected.

(2) Prior Art The applicant of the present invention has previously proposed a Japanese Patent Publication No. 4-38954 as a joint type in which a packing having a self-sealing action is held by a push ring that is advanced by a tightening operation of a tightening tool.
And Japanese Patent Application No. 60-250954. Therefore, according to these prior arts, although they exhibit good stretchability and flexibility, the front and rear walls (including the push ring) are used to hold the packing, so that the inner surface and the insertion opening Since the outer peripheral surface of the portion contacts at two points, the flexibility is naturally limited. Furthermore, when the joint portion is greatly tilted, the push wheel and the insertion opening come into contact with each other, causing a displacement displacement between the push wheel and the flange against which the push wheel is pressed, and the push wheel and the flange are interposed. When the tightening bolt mounted is sheared and the shearing force becomes excessive, the tightening bolt is broken.

(3) Problems to be Solved by the Invention In view of the above circumstances, the present invention prevents the packing from being removed with respect to both internal pressure and external pressure, and maintains good water-stopping property even in an inclined state. Another object of the present invention is to provide a pipe joint structure in which no harmful force is applied to the tightening bolts of the push ring when the connecting pipe is excessively inclined.

B. Configuration of the Invention (1) Means for Solving Problems The pipe joint structure of the present invention adopts the following configuration (technical means) in order to achieve the above object. That is, in a pipe joint constructed by coaxially inserting a small-diameter pipe part having the same shape as a circular pipe into a large-diameter pipe part having a circular pipe shape, the end of the large-diameter pipe part is formed. A ring-shaped flange having a bolt insertion hole with a fixed thickness is fixedly provided on the outer peripheral surface in the vicinity of the portion, and the pressing ring is formed of an integral annular body that is disposed over the pipe end of the large-diameter pipe portion. The member has an inner flange having an inner diameter larger than the outer diameter of the large-diameter pipe portion and a larger diameter than the outer diameter of the flange at a portion extending outwardly from the large-diameter pipe portion. An outer flange having an inner diameter of 10 mm, which fits into the flange with an allowable clearance, is provided so as to protrude through the body wall of the intermediate portion, and the body wall of the intermediate portion corresponds to the bolt insertion hole of the flange. A part where a bolt insertion hole is opened and extends inward from the inner flange. In which the rear portion of the packing is abutted and supported, and the push ring member is advanced toward the flange by a fastener having a bolt inserted into a bolt insertion hole of the flange and the push ring member, and the packing is a heel portion. The heel portion is sandwiched and gripped by the packing contact surface of the push ring member and the rear end surface of the large-diameter pipe portion.

(2) Action In the tightening operation of the push wheel member, the packing is compressed and sandwiched between the rear end surface of the large-diameter tube portion and the front end surface of the push wheel with the heel portion of the packing due to the forward movement of the push wheel member. ,
It is firmly attached to the end of the large diameter pipe. Further, the packing holding portion of the push wheel substantially closes the gap between the large diameter pipe portion and the small diameter pipe portion, and prevents the valve portion from being pulled out. When the push ring comes into contact with the small-diameter pipe section due to the subsidence and bending displacement of the connecting fluid pipe, causing a displacement displacement with the flange,
The outer brim of the push ring abuts the flange to prevent a breaking force on the fastener bolt inserted through the two bolt insertion holes and prevent a displacement that excessively compresses the packing.

(3) Example An example of the pipe joint structure of the present invention will be described with reference to the drawings. (Structure of Embodiment) FIGS. 1 to 4 show an example of application of the embodiment to a flexible expansion joint tube. That is, FIG. 1 shows the entire side surface and vertical sectional configuration, and FIG. 2 shows the front surface thereof.
3 and 4 show the partial configuration. In the following terms, the front and rear surfaces are defined in the tightening forward direction (a direction) of the push ring, and the inner and outer surfaces are defined in the pipe radial direction.

In FIGS. 1 and 2, T is an expandable flexible joint pipe of this embodiment, and P is two fluid pipes connected to each other via the joint pipe T. This joint pipe T is
A sleeve tubular portion 1 having a circular tubular shape arranged in a central portion; two insertion tubular portions 2 concentrically fitted into the sleeve tubular portion 1 from both ends of the sleeve tubular portion 1; 1 includes a packing 3 that is watertightly mounted in an annular gap between the insertion tube portion 1 and the insertion tube portion 2; and a push ring 5 that is fitted to both ends of the sleeve tube portion 1 and that has a fastener 4. In this example,
The sleeve pipe portion 1 corresponds to the large diameter pipe portion of the present invention, and the insertion pipe portion 2 corresponds to the small diameter pipe portion.

The detailed structure of each part will be described below with reference to FIGS. Sleeve tube portion 1 The sleeve tube portion 1 is composed of a sleeve tube 7 having a circular tubular shape, and a flange 8 fixed to the outer peripheral surface near both ends of the sleeve tube 7. The sleeve tube 7 is usually made of steel, although other materials are not excluded. Reference numeral 7a is an outer peripheral surface of the sleeve tube 7, 7b is an inner peripheral surface thereof, and 7c is an end surface thereof. The end surface 7c is a smooth surface due to the nature of the present invention, and its inner edge is appropriately chamfered. The flange 8 is formed of a steel annular body having a predetermined thickness, and is fixed to the outer peripheral surface 7a of the sleeve tube 7 by welding at a predetermined distance from the end surface 7c of the sleeve tube 7. At least the outer diameter of the flange 8 is formed into a perfect circle. A plurality of (10 in this embodiment, equidistant) bolt insertion holes 9 are formed in the flange 8 at predetermined intervals in the circumferential direction.

[0009] inserted pipe section 2 inserted pipe section 2, a circle tubular predetermined thickness, the front end face is chamfered 2a is subjected, the flange portion 10 which forms a connection between the fluid conduit P is fixed to the rear It Reference numeral 10a is a bolt insertion hole formed in the flange portion 10. On the other hand, a flange portion 100 is opened in the fluid pipe P, a gasket 102 is sandwiched between the flange portions 10 and 100, and a bolt insertion hole 100a formed in the flange portion 100 and a bolt insertion hole 10a of the flange portion 10 are formed. The connection with the fluid pipe P is made by a fastener (not shown) that is inserted over. It should be noted that the manner of connection with the fluid pipe P is not essential to the present invention, and is not limited to the illustrated example, and other appropriate joint structures can be adopted.

Packing 3 The packing 3 is composed of a heel portion 12 which is held by that portion and a valve portion 13 which stops water by a self-sealing action. FIG. 4 shows a detailed structure of the packing 3, and further shows a natural state, that is, an uncompressed state. As shown in the drawing, the heel portion 12 and the valve portion 13 are concatenated in a constricted manner, the front step 14a abuts the end surface 7c of the sleeve tube 7, and the rear step 14b is the engagement step 2 of the push wheel 5.
Engage 1. In the figure, B indicates the width taken by the heel portion 12 in the natural state. Thus, the heel portion 12 is sandwiched and held by the end surface 7c of the sleeve tube portion 1 and the push ring 5, as will be described later, and the valve portion 13 is formed in the gap between the sleeve tube 7 and the insertion opening portion 2 described above. It is compressed in the space with a predetermined compression margin, receives the acting fluid pressure, and stops water by its self-sealing action.

Pushing Wheel 5 The pushing wheel 5 is formed of an integral annular body along a plane orthogonal to the tube axis, and is fitted over the end surface 7c of the sleeve tube 7.
Then, the push wheel 5 is extended outward in the radial direction from the sleeve tube 7 and holds the fastener 4 (outer portion) 5a.
And a portion (inward portion) 5b that extends inward of the sleeve pipe 7 and holds the packing 3.

FIG. 3 shows a fixed mounting position of the push wheel 5. As shown in the drawing, in the outer portion 5a, an inner flange 17 is placed inwardly with a vertical main body wall 16 interposed therebetween. Outer collars 18 are formed in parallel with each other and project in an annular shape in different directions, and bolt insertion holes 19 are opened in the main body wall 16 at predetermined intervals in the circumferential direction. More specifically, the bolt insertion holes 19 correspond to the bolt insertion holes 9 of the flange 8, and in this embodiment, the bolt insertion holes 19 are opened at 10 positions at equal intervals in the circumferential direction. The tightening tool 4 assembled to the outer portion 5a is composed of a bolt 4a and a nut 4b. It is tightened with 4b. Note that the bolt 4a
The bolt rod is inserted into the two bolt insertion holes 9 and 19 with a clearance, and this clearance allows the push ring 5 and the flange 8 to be displaced. The inner brim 17 is the main wall 1
6 has a predetermined length and thickness, and has an inner diameter larger than the outer diameter of the sleeve tube 7. The front end face 17 of the inner flange 17 is fixed at the fixed position of the push ring 5.
The a contacts the flange 8. The outer brim 18 is the main body wall 1.
6 has a predetermined length and thickness, and has an inner diameter larger than the outer diameter of the flange 8. Push ring 5
In the fixed mounting position of, the outer diameter surface of the flange 8 is fitted with a predetermined gap α. This gap is smaller than the gap β between the inner flange 17 and the sleeve tube 7.

At the inner portion 5b, the packing gripping surface 20, is directed inward from the lower surface of the rear end of the inner collar 17.
An engagement step portion 21 and a backup surface 22 are formed respectively. The packing gripping surface 20 and the backup surface 22 are vertical surfaces, and the engagement stepped portion 21 is a right cylindrical surface, but they can be slightly inclined. Packing gripping surface 20
Sufficiently includes the thickness of the sleeve tube 7 in its vertical projection. The engagement step portion 21 may be omitted in association with the shape of the packing 3 or independently. The distance b between the packing gripping surface 20 and the end surface 7c of the sleeve tube 7 at the fixed position of the push wheel 5 is sufficiently smaller than the width B of the heel portion 12 of the packing 3 in the natural state.

(Operation / Effect of Embodiment) The expandable flexible joint tube T of this embodiment having the above-described structure operates as follows. First, the procedure for assembling the expansion / contraction flexible joint tube T will be described. (1) In the push wheel 5 from which the fastener 4 has been removed, the rear surface step 14b of the packing 3 is engaged with the packing gripping surface 20 and the engagement step 21 of the inner part 5b.

(2) The push ring 5 is attached to the bolt insertion hole 19 thereof.
Is attached to the end portion of the sleeve tube 7 in phase with the bolt insertion hole 9 of the flange 8. At this time, the step portion 14a on the front surface of the packing 3 is brought into light contact with the end surface 7c of the sleeve tube 7. In this state, the bolt 4a of the tightening tool 4 is inserted from the bolt insertion hole 19 of the push wheel 5 into the bolt insertion hole 9 of the flange 8, and the nut 4b is screwed. FIG. 5 shows this state.

(3) In this state, the nut 4b of the tightening tool 4
Rotate and tighten. As a result, the push wheel 5 advances forward in the direction of the sleeve tube 7 (direction of FIG. 3 and FIG. 5, a direction) with a large tightening force, and the heel portion 12 of the packing 3 and the packing gripping surface 20 of the push wheel 5 and the sleeve tube. 7, and the outer flange 18 of the push ring 5 is fitted into the outer edge of the flange 8 with a predetermined gap. This forward movement is stopped by the front end 17a of the inner brim 17 coming into contact with the flange 8, or the packing 3
The heel portion 12 receives a predetermined compression and stops with its resistance.

(4) Next, the insertion tube section 2 is inserted into the sleeve tube section 1 via the packing 3. At this time, since the end surface of the insertion tube portion 2 is chamfered 2a, the packing 3 is not damaged, and the heel portion 12 of the packing 3 is firmly gripped by the push ring 5, so that the packing 3 cannot be removed. Absent.

Through the above steps, the flexible joint tube T for expansion and contraction
The assembly of is completed. This assembly is usually done in a factory, but of course it may be done in the field.

(5) The stretchable flexible joint pipe T assembled in this manner is disposed on the site by interposing two fluid pipes P forming a connection. That is, the flange 10 of the insertion pipe portion 2 of the main joint pipe T and the flange 100 of the fluid pipe P.
And the gasket 102 are interposed and fixed by bolts and nuts (not shown) for the joint. The joint pipe T is used in the above-ground portion, the underground portion, and the pipe portion where expansion and contraction and bending occur in the indoor portion. Note that earth pressure and water pressure due to groundwater act on the joint pipe T buried in the underground portion. Furthermore, the forced bending force that accompanies the ground subsidence also works.

Next, the watertight action of the expandable flexible joint tube T in the steady state will be described. When the fluid is conducted to the fluid pipe P, the fluid pressure also acts on the expandable flexible joint pipe T and acts on the valve portion 13 of the packing 3. The valve portion 13 is compressed by the action of this fluid pressure, and acts as a surface pressure to the inner side surface 7b of the sleeve tube 7 and the outer side surface of the insertion tube 2 while maintaining elasticity, so that a so-called self-sealing action is achieved. , Exerts a good waterproofing effect. Further, the packing 3 is firmly fixed and gripped by the heel portion 12 even when the fluid pressure is excessive, and the backup surface 22 of the push ring 5 is further fixed.
Since the rear surface of the packing 3 is substantially closed, the packing 3 is not pulled out. In addition, even when an external pressure such as groundwater or a negative pressure is generated in the fluid pipe P, the packing 3 does not come out by gripping the heel portion 12.

Now, when one or both of the fluid pipes P expands and contracts due to temperature changes, ground subsidence, etc.,
Further, when a bending force acts and the pipe tilts, this displacement acts on the main flexible joint pipe T, but since the valve portion 13 of the packing 3 of the main flexible pipe T retains elasticity, the expansion and contraction displacement and the bending displacement. Absorb without resistance.

When a larger bending force is applied to the expandable flexible joint tube T to incline it, the inner surface of the push ring 5 comes into contact with the outer surface of the insertion tube portion 2 at one position on the circumference. Become. FIG. 6 shows this state. When the push ring 5 is further pressed, the push ring 5
Causes a displacement displacement in the direction of (b) with the flange 8 of the sleeve tube portion 1, but at the circumferentially opposed positions, the outer flange 18 of the push ring 5 abuts the outside of the flange 8 and tightens. This offset displacement is prevented before a harmful shearing force is generated on the bolt rod of the bolt 4a of the tool 4.

As described above, according to the expansion / contraction flexible joint tube T of this embodiment, the packing 3 has the rear end surface 7 of the sleeve tube 7.
Since the heel portion 12 is compressed and sandwiched between c and the front surface of the pushing wheel 5 that is advancing, and is firmly held, when an excessive internal pressure is applied, a pressure from the outside or a negative pressure in the fluid pipe P is generated. Even if pressure is applied, the packing 3 is not pulled out. Further, even if the main flexible joint pipe T is excessively inclined due to the inclination of the fluid pipes P to be connected to each other, the bolt 4a of the tightening tool 4 is engaged due to the engagement between the outer flange 18 of the push ring 5 and the flange 8. It counters the tilt without transmitting any harmful shearing forces to it. The flange 8 of the main joint pipe T has a high roundness, and therefore, the accuracy of the clearance α with the outer collar 18 is high, that is, the fitting accuracy is high, and there is an advantage that no discrepancy occurs in the fixed mounting position. Further, according to the expandable flexible joint tube T, there is no complicated inner surface processing on the sleeve tube 7, and the end portion thereof is used as the holding surface of the packing 3 to simplify the structure and reduce the processing labor. sell. Especially for small diameter pipes, there is a demand for a simple packing holding mechanism,
The joint pipe T of the present embodiment is suitable for this and is useful for small diameter pipes.

In the above embodiment, the upper portion 5a of the push wheel 5 is
In the above, the inner brim 17 and the outer brim 18 were projected in different directions. However, as shown in FIG. It is equivalent in effect. In this aspect, as is clear from the figure, the bolt 4a of the tightening tool 4 is long.

The present invention is not limited to the above embodiments, but various design changes can be made within the scope of the basic technical idea of the present invention. That is, the following aspects are included in the technical scope of the present invention. In the present embodiment, the watertight structure having the same structure is arranged at both ends of the sleeve pipe portion 1, but one shown in the figure is provided at one end of the sleeve pipe portion 1, and the other end has another joint structure, for example, a flange joint. It is free to provide. The main pipe joint structure is not limited to expansion and contraction flexible joint pipes, and it is a matter of course to apply it to a normal socket type joint consisting of a receiving pipe (large diameter pipe) and an insertion pipe (small diameter pipe). .

C. Effects of the Invention According to the present invention, it is possible to realize a pipe joint that exhibits great flexibility, retains good water blocking properties, and is easy to manufacture because of its simple structure. In addition, since the heel of the packing is compressed and sandwiched between the rear end surface of the large-diameter pipe and the front end surface of the advancing push ring, the packing is firmly held. Even if pressure or a negative pressure is generated in the fluid pipe, the packing is not extracted. Further, even if the main joint portion is excessively inclined due to the subsidence and bending displacement of the connecting fluid pipe, the outer flange of the push ring and the flange do not transmit a harmful shearing force to the bolt of the fastener, Counter the tilt.

[Brief description of drawings]

FIG. 1 is an overall side sectional view of an embodiment (expandable flexible joint pipe) of a pipe joint of the present invention.

FIG. 2 is a sectional view taken along line II in FIG.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is a sectional view of the packing.

FIG. 5 is a diagram showing a procedure for assembling the main pipe joint.

FIG. 6 is a view showing a flexible state when tilting.

FIG. 7 is a cross-sectional view of a main part of a pipe joint having a push ring of another aspect.

[Explanation of symbols]

P ... Connection pipe, T ... Expansion / contraction flexible joint pipe, 1 ... Sleeve pipe portion (large diameter pipe portion), 2 ... Inlet pipe portion (small diameter pipe portion), 3 ... Packing, 4 ... Tightening tool, 5 ... Push ring, 5a ... Outer part, 5b
… Inner part, 8… Flange, 9… Bolt insertion hole, 12…
Heel part, 13 ... Valve part, 16 ... Main body wall, 17 ... Inner brim, 18 ... Outer brim, 19 ... Bolt insertion hole

Claims (1)

[Claims] 1. A pipe joint constructed by coaxially inserting an annular small-diameter pipe portion into an annular large-diameter pipe portion via packing having an annular self-sealing action, wherein the large-diameter pipe is formed. An annular flange having a bolt insertion hole with a constant thickness is fixedly provided on the outer peripheral surface near the end of the portion, and an integral annular body is arranged across the pipe end of the large diameter pipe portion. (A) the inner ring having an inner diameter larger than the outer diameter of the large-diameter pipe portion and the flange of the flange at the portion extending outward from the large-diameter pipe portion. An outer flange, which has an inner diameter larger than the outer diameter and fits into the flange with an allowance gap, is projected through the body wall of the intermediate portion, and the flange of the flange is attached to the body wall of the intermediate portion. A bolt insertion hole corresponding to the bolt insertion hole is opened, and (b) extends inward from the inner flange. In a portion to be contacted with and supporting the rear portion of the packing, the push ring member is advanced toward the flange by a fastener having a bolt inserted into a bolt insertion hole of the flange and the push ring member, and the packing is A pipe joint structure comprising a heel portion and a valve portion, wherein the heel portion is sandwiched and gripped by a packing contact surface of the push wheel member and a rear end surface of the large diameter pipe portion.