JP4505785B2 - Olefin resin fittings - Google Patents

Description

  The present invention relates to a structure of a joint made of olefin resin having a receiving portion fused and joined to an insertion portion of the pipe and / or joint made of olefin resin. More particularly, the present invention relates to a joint structure capable of reliably fusion-bonding a pipe and / or joint insertion portion of an outer diameter of 140 mm to 1000 mm and a joint receiving portion.

  Conventionally, various joints made of olefin resin that are fusion-bonded have been proposed. As an example, there is a pipe joint 23 that is joined by thermal fusion as shown in FIG. 9 (for example, Patent Document 1). reference). In the pipe joint 23, a collar portion 25 having a slightly larger diameter than the connection port portion 24 is concentrically extended from the cylindrical connection port portion 24 of the pipe joint 23. Is provided between the collar portion 25 and the resin tube 27 when the pipe end 28 of the resin tube 27 is fitted inside the connection port 24. A resin receiving space 29 having an axial length L1 is formed. The effect is that the inner periphery of the connection port 24 and the outer periphery of the tube end 28 of the resin tube 27 are heated, and the tube end 28 of the resin tube 27 is internally fitted to the connection port 24 and the overlapping portions thereof are thermally fused. Then, the excess molten resin generated by heat fusion protrudes to the outer periphery of the overlapping portion, enters the resin receiving space 29, rises on the ring at the stepped portion 26 and is cured, and is heat-sealed to each other. Even if the base portion 30 between the connection port portion 24 on the pipe joint 23 side and the resin tube 27 is stress concentrated in shape, the effect that the resin tube 27 is not easily broken at the base portion 30 and heat fusion The effect of being able to easily confirm visually whether the state is good or not was obtained.

Japanese Patent Laid-Open No. 11-201362 (page 4, FIG. 1)

  However, in the conventional olefin-based resin pipe joint 23 to be fusion-bonded, the dimensions are not suitable for optimum fusion with respect to a large-diameter (for example, 140 mm or more). The problem that there is a risk of causing poor fusion, and as the diameter increases, stress is concentrated in the gap between the end faces of the inserted resin pipe 27 at the center of the inner periphery of the pipe joint 23 when a high water pressure is applied to the pipe. Thus, there is a problem that the joint may be damaged from the gap portion.

  Further, in the fusion work, when the pipe joint 23 having an outer diameter of 140 mm or more is clamped and fixed to the pipe joint joining fusion machine (hereinafter referred to as a fusion machine) with a clamp, There was a problem that it was easy to shift and it was difficult to fix the pipe joint 23 at a position suitable for fusion. Furthermore, since the insertion load applied when the heat-melted resin pipe 27 is inserted into the connection port portion 24 increases as the diameter increases, the pipe joint 23 can be held against the insertion load only by fixing with a clamp. However, there is a problem that the pipe joint 23 slips from the clamp and the fixing position is shifted, or the pipe joint 23 is detached from the clamp, resulting in poor fusion. On the other hand, when the pipe joint 23 is fixed by tightly tightening the clamp so that the pipe joint 23 does not slip out of the clamp, the pipe joint 23 is flattened and uneven fusion occurs. Furthermore, there is a problem that the clamp is easily broken.

  The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to ensure fusion bonding, and even if high pressure is applied to the inside of the pipe, it is applied to the gap portion of the joint. It is used without problems even under high pressure without concentrating stress, and positioning and centering are easy when fixing the joint with a clamp at the time of fusion, and the joint does not slip or disengage from the clamp at the time of fusion joining An object of the present invention is to provide an olefin resin joint.

The configuration of the present invention for solving the above problems will be described with reference to FIGS. 1 and 2. An olefin having a receiving portion into which an end portion of an olefin resin pipe and / or joint is inserted and heat-sealed is inserted. In joints made of resin,
D (mm): outer diameter of the insertion portion of the pipe and / or joint,
L (mm): length of the receiving portion of the joint,
Z (mm): the length of the straight portion from the end of the joint to the center of the joint (however, when the joint is a straight pipe, “center” means the midpoint between the two ends of the joint, When the joint is a curved pipe, the “center” is defined as the intersection of the axes of the two receiving portions of the joint).
θ: bent pipe angle when the joint is a bent pipe joint,
When
1) 0.25D <L <0.32D
2) 0.08D (1 + sin θ) <Z
3) 140 ≦ D ≦ 1000
The first feature is that at least two protrusions 9, intermittent protrusions 10, or flanges 5 are provided on the outer periphery of at least one end of the joint 1. A second feature is that when the clamp is set, it is fixed so as to hit the edge of the clamp.

The relationship between the outer diameter D of the pipe 3 and / or the joint insertion portion 2 used in the present invention and the length L of the receiving portion 4 of the joint 1 is in the range of 0.25D <L <0.32D. Is more preferable.
(1) When 140 ≦ D ≦ 200, 0.28D <L <0.32D,
(2) When 200 <D ≦ 500, 0.26D <L <0.30D,
(3) When 500 <D ≦ 1000, 0.25D <L <0.28D
More preferably, it is the range. 0.25D <L is good in order to obtain sufficient strength of the joint portion, and the insertion load when inserting the insertion portion 2 into the receiving portion 4 is suppressed, and the length of the joint 1 is increased by increasing the length of the joint 1, thereby improving the moldability. L <0.32D is preferable in order to suppress difficulty and increase in material cost.

Based on FIGS. 7 and 8, the outer diameter D of the insertion portion 16 of the pipe 17 and the length Z of the straight portion from the end of the receiving portion 18 of the joint 14 to the center (the intersection of the axes of both receiving portions 18) When the joint 14 is a bent pipe joint such as a bend (elbow), the relationship with the curved pipe angle θ (0 ° ≦ θ ≦ 90 °) is in the range of 0.08D (1 + sin θ) <Z. A range of 08D (1 + sin θ) <Z <0.13D (1 + sin θ) is more preferable. 0.08D (1 + sin θ) <Z is good so that stress is not concentrated in the gap 21 portion of the joint 14 when internal pressure is applied to the piping. In order to suppress the increase in cost, Z <0.13D (1 + sin θ) is good.

(1) It is possible to obtain a joint in which a tube having an outer diameter of 140 mm to 1000 mm and / or a joint and a joint receiving portion are securely fused and joined.
(2) It is possible to alleviate the concentration of stress generated in the gap portion of the joint in the pipe by the internal pressure, and to prevent the joint from being damaged by the high internal pressure.
(3) By fixing the step portion of the joint so as to hit the edge of the clamp, the joint can be centered with respect to the axis of the fusion machine, and the joint is always positioned at a fixed position. The joint can be set in the fusion machine in a state most suitable for fusion bonding.
(4) When inserting the pipe and / or joint insertion part into the joint and fusion-bonding it, fix the joint so that it does not slip and disengage from the clamp due to a large insertion load. Can do.

  Hereinafter, examples of the present invention will be described with reference to the drawings. However, it is needless to say that the present invention is not limited to the examples.

  FIG. 1 is a longitudinal sectional view of a socket-shaped joint according to a first embodiment of the present invention, FIG. 2 is an enlarged longitudinal sectional view of a main part of FIG. 1, and FIG. FIG. 4 is a vertical cross-sectional view showing a state at the time of heating, and FIG. 4 is a vertical cross-sectional view showing a state where a pipe is inserted into a heat-melted joint. FIG. 5 is a longitudinal sectional view showing a state in which a pipe is fused and joined to both receiving portions of the joint of FIG. FIG. 6 is a perspective view showing another embodiment of the protrusion provided on the outer periphery of the end of the joint. FIG. 7 is a longitudinal sectional view of a 90 ° elbow-shaped joint showing a second embodiment of the present invention, and FIG. 8 is a longitudinal sectional view showing a state where pipes are fused and joined to both receiving portions of the joint of FIG. FIG.

  Hereinafter, a socket-shaped olefin-based resin joint which is a first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 5, and 6.

   In the figure, reference numeral 1 denotes a socket-shaped polypropylene joint that is fusion-bonded to a polypropylene tube 3 having an outer diameter D of an insertion portion 2 of 180 mm.

  Reference numeral 4 denotes a receiving portion provided on the inner periphery of both ends of the joint 1. The inner diameter of the receiving portion 4 is the same as or slightly smaller than the outer diameter D of the tube 3 and is provided so as to be gradually reduced in diameter toward the inner portion. The length L of the receiving portion 4 is the insertion depth of the tube 3 and is set to 54 mm.

  Reference numeral 5 denotes a flange provided on the outer periphery of both ends of the joint 1. The outer diameter D1 of the flange portion 5 is set to 1.01D2 with respect to the outer diameter D2 of the joint 1, and the outer diameter D1 of the flange portion 5 prevents the stepped portion 8 from slipping from the clamp 6 at the time of fusion bonding. In order to act as a stopper, it is necessary that 1.002D2 <D1. The length S from the end face of the joint 1 to the stepped portion 8 is set to the heater 13 when the stepped portion 8 of the flange portion 5 is fixed to the side surface of the clamp 6 at the time of setting in the fusion machine and fusion bonding. The joint 1 is set to a position suitable for fusion. In addition, although the present Example is the collar part 5, the protrusion 9 provided in the outer periphery like FIG. 6 (a) at equal intervals, and several notches along the outer periphery like FIG.6 (b) A structure in which at least two protrusions 9 and intermittent protrusions 10 are provided on the outer periphery of at least one end of the joint 1, such as an intermittent protrusion 10 having a portion (preferably provided at opposite positions) ), Or any shape that has a function of positioning and preventing slippage from the clamp 6.

  11 is a chamfered portion provided on the outer periphery of the joint 1 end. The chamfered portion 11 is provided at 30 ° with respect to the axis, but may be within a range of 10 ° to 45 °. By providing the chamfered portion 11, it is prevented from being caught at the end of the joint 1 at the time of piping construction, and can be easily performed at the time of fusion work or piping construction.

  Reference numeral 12 denotes a gap formed between the joint 1 and each end of the tube 3 after the insertion portion 2 of the tube 3 is fusion bonded to both the receiving ports 4 of the joint 1 (state of FIG. 5). In the case of the socket shape, the length of the gap 12 is represented by 2Z and is set to 36 mm.

    In addition, although it is the pipe | tube 3 in a present Example, it may be a pipe | tube and / or joint with the insertion part 2 which is fusion-bonded to the receptacle part 4 of the coupling 1, such as a pipe with a receptacle, a reducer, and cheese. Any may be used.

  Next, an operation when the socket-shaped joint 1 and the pipe 3 according to the first embodiment are fusion-bonded by using a fusion machine will be described with reference to FIGS.

   First, the joint 1 is set on one clamp 6 of the fusion machine, and the tube 3 is set on the other clamp 7. At this time, by fixing the step portion 8 of the joint 1 so as to contact the edge of the clamp 6, the joint 1 suitable for fusion bonding can be easily positioned, and the length from the end surface of the joint 1 to the step portion 8 can be easily determined. Since the length S is determined, the joint 1 and the insertion position of the heater 13 are always constant, and the fusion conditions can be made the same. Further, if the step 1 of the joint 1 is fixed so that it touches the edge of the clamp 6, the axis of the joint 1 and the axis of the clamp 6 are aligned to adjust the centering. Therefore, it is possible to easily fix, and it is possible to prevent a mis-fusing or uneven fusing of the fusing portion 15 due to a defect in a fixing position or a deviation of the axis, and to perform reliable fusing.

  Next, as shown in FIG. 3, the outer periphery of the insertion portion 2 of the tube 3 and the inner periphery of the receiving portion 4 of the joint 1 are heated by the heater 13. After heating in an appropriate time, the tube 3 and the joint 1 are separated from the heater 13, and the insertion portion 2 of the tube 3 is inserted into the receiving portion 4 of the joint 1 without leaving time. At this time, if the diameter is 140 mm to 1000 mm, the joint 1 tends to slip or disengage from the position set by the clamp 6 due to the insertion load when the tube 3 is inserted into the joint 1. Since the flange portion 5 is provided at the end portion, the step portion 8 is hung on the edge of the clamp 6 to prevent the joint 1 from moving, and it is stable without slipping off the clamp 6 or coming off the clamp 6. Fusion bonding can be performed. Further, since it is only necessary to tighten the clamp 6 with an appropriate force, it is possible to prevent the flattening of the joint 1 and the damage to the clamp 6 caused by tightening the clamp 6 tightly.

  When the tube 3 is inserted into the joint 1, the state is fixed for a certain period of time (the state shown in FIG. 4). After the fused portion 15 is cooled, the joint 1 and the tube 3 are removed from the clamp 6. Subsequently, the other receiving portion 4 of the joint 1 is fusion-bonded by the same method, and after the cooling, the fusion-joining operation is completed by removing it from the clamp 6 (state of FIG. 5).

  Since the relationship between the length L of the receiving portion 4 of the joint 1 which is the insertion depth of the pipe 3 and the diameter D is set as 0.25D <L <0.32D, sufficient fusion strength can be obtained. It is possible to perform fusion bonding without applying an insertion load so much.

  In addition, if the length 2Z of the gap 12 is too short, stress concentrates on the portion of the gap 12 formed between the end faces of the pipe 3 inserted when internal pressure is applied to the pipe line, so that the breakage occurs. In the case of the present embodiment, since the joint 1 is a socket-shaped joint, the bent pipe angle θ = 0 °, and 0.08D (1 + sin θ) <Z, that is, by setting Z in the range of 0.08D <Z, a low internal pressure It is possible to prevent damage due to stress concentration. In addition, when the gap is lengthened, the stress concentration is eliminated. On the other hand, in order to suppress the difficulty in formability due to the increase in the size of the joint 1 and the increase in the material cost, the joint 1 has a socket shape. Since it is a joint, the bent pipe angle θ = 0 ° and Z <0.13D (1 + sin θ), that is, Z is set in a range where Z <0.13D.

  Hereinafter, a 90 ° elbow-shaped olefin resin joint that is a second embodiment of the present invention will be described with reference to FIGS. 7 and 8.

   7 and 8, reference numeral 14 denotes an elbow-shaped polypropylene joint, which is fusion-bonded to a polypropylene tube 17 having an insertion portion 16 with an outer diameter D of 180 mm.

  Reference numeral 18 denotes a receiving portion provided on the inner periphery of both ends of the joint 14. The inner diameter of the receiving portion 18 is the same as or slightly smaller than the outer diameter D of the tube 17 and is provided so as to be gradually reduced in diameter toward the back. The length L of the receiving portion 18 is the insertion depth of the tube 17 and is set to 54 mm.

  Reference numeral 19 denotes a flange provided on the outer periphery of both ends of the joint 14. Reference numeral 20 denotes a chamfered portion provided on the outer periphery of the end portion of the joint 14. Since the detailed description of the collar part 19 and the chamfered part 20 is the same as that of the first embodiment, the description thereof is omitted.

Reference numeral 21 denotes a gap formed between the joint 14 and each end portion of the pipe 17 when the both receiving ports 18 of the joint 14 and the insertion portion 16 of the pipe 17 are fusion-bonded (state of FIG. 8). Of the void 21, Z dimension Ri length der of the linear portion between the axis intersection of the receiving portion 18 terminating from both the mouth part 18 of the joint 14, i.e., the bent portion from the mouth part 18 terminating in the present embodiment The length is up to 22 and is set at 36 mm.

  Next, the operation when the elbow-shaped joint 14 and the pipe 17 of the second embodiment are fusion-bonded using a fusion machine will be described with reference to FIGS.

  First, the joint 14 is set to one clamp of the fusion machine, and the pipe 17 is set to the other clamp. Since the procedure of fusion bonding is the same as that of the first embodiment, description thereof is omitted.

  Since the length L of the receiving portion 18 which is the insertion depth of the tube 17 is designed to satisfy 0.25D <L <0.32D, sufficient fusion strength can be obtained, and an insertion load is not applied so much. It is possible to fuse and bond to each other.

  In the case of a 90 ° elbow, if the length of the linear portion of the gap 21 from the end of the inserted tube 17 to the bent portion 22 is too short, when the internal pressure is applied to the pipe line, particularly in the bent portion 22. Since stress concentrates, it is necessary to provide an appropriate interval, and it is necessary to set the distance from the end of the tube 17 of the 90 ° elbow to the bent portion 22 so that stress against the internal pressure is not concentrated. .08D * 2 <Z must be satisfied. Further, as the bent tube angle θ of the joint 14 becomes smaller, the stress at the bent portion 22 of the elbow becomes lower, so the distance from the end of the tube 17 to the bent portion 22 becomes narrower, and the bent tube angles θ and Z are 0.08D (1 + sin θ) < It is preferable to have a Z relationship. In addition, as Z becomes longer, the concentration of stress is eliminated. On the other hand, since the joint 14 becomes larger, difficulty in formability and increase in material cost occur. Therefore, in order to suppress these, Z <0.13D ( It is preferable to set Z within a range of 1 + sin θ).

  In the first and second embodiments, the pipes 3 and 17 and the joints 1 and 14 are made of polypropylene, but may be made of any olefin resin such as polyethylene or polybutene.

  In the first and second embodiments, the joints 1 and 14 have a socket shape and an elbow shape, but may have a cheese shape or a reducer shape. In the cheese shape, the conditions in the case of the 90 ° elbow shape are applied and set, and in the reducer shape, the conditions are applied to the diameter of each receiving portion.

Next, in the first embodiment, the length L of the receiving portion 4 of the socket-shaped joint 1 (θ = 0 °) and the center from the end of the receiving portion 4 (the midpoint between the ends of both receiving portions 4). When the length Z of the straight line portion was changed, the performance against the internal pressure of the joint 1 in which the pipe 3 was fused was evaluated according to the following method. This will be described with reference to FIG.

(Destructive water pressure test)
Based on the water distribution polyethylene association standard PWA001, in a 23 ± 2 ° C atmosphere, pressurize at a constant water pressure until the pipe specimen breaks inside the pipe specimen length of 1 m to which the joint 1 is joined. Measure the maximum pressure when the specimen breaks. In addition, if the maximum value of a pressure is 6.0 Mpa or more, it will be set as a pass.

  In the socket-shaped polypropylene joint 1 for joining the polypropylene pipes 3 with D of 140 mm, 180 mm, and 225 mm, the results of the destructive hydraulic pressure test when L = 0.28D are shown in Example 1, Example 2, and Example 3. Are shown in Table 1, respectively.

In the socket-shaped polypropylene joint 1 for joining the polypropylene pipes 3 with D of 140 mm, 180 mm, and 225 mm, the results of the destructive hydraulic pressure test when L = 0.10 D are shown in Comparative Example 1, Comparative Example 2, and Comparative Example 3. Are shown in Table 1, respectively.

In the socket-shaped polypropylene joint 1 that joins the polypropylene pipes 3 with D of 140 mm, 180 mm, and 225 mm, the fracture hydraulic pressure test results when L = 0.23D are shown in Comparative Example 4, Comparative Example 5, and Comparative Example 6. Are shown in Table 1, respectively.

In the socket-shaped polypropylene joint 1 for joining the polypropylene pipes 3 with D of 140 mm, 180 mm, and 225 mm, the results of the destructive hydraulic pressure test when L = 0.35D are Comparative Example 7, Comparative Example 8, and Comparative Example 9 Are shown in Table 1, respectively.

As can be seen from Table 1, in Examples 1 to 3, there is no problem in performance. In Comparative Examples 1 to 3, since the area of the fused portion 15 (see FIG. 5) is small and the fusion strength is insufficient, it was damaged from the vicinity of the fused portion. In Comparative Examples 4 to 6, since the fusion error is included in the range of L, so long as the fusion bonding is surely performed, even if it is slightly out of the range of 0.25D <L Although it is possible to maintain the strength that can withstand use, in the range of 0.25D <L, the area of the fused portion needs to be at least the cross-sectional area of the pipe 3 that is a pipe joint. When the thickness of the insertion portion 2 is determined as t,
π (D-2t) 2/4 ≦ πDL
Since t (see FIG. 1) can be calculated as D / 11 at the minimum, substituting it into the above equation,
0.167D ≦ L
It becomes. Even if the insertion amount when inserting the insertion portion 2 into the receiving portion 4 is set to be constant with respect to 0.167D, the variation in fusion due to the performance of the operator and the fusion machine and the environment. Thus, there are cases where only a minimum of 80% of the set insertion amount is inserted, and in the set fusion portion, about 10% of the area in the vicinity of the end of the joint 1 and the pipe 3 is the axis line. This is a region where there is a case where it cannot be completely welded due to a deviation or a welding error. Therefore, considering the case where the insertion portion 2 is inserted only up to 80%, the range of L is set by further increasing the fusion area by 20%,
0.167D / 0.8 * 1.2 = 0.25D
It becomes. Therefore, it is necessary that 0.25D <L in order to obtain sufficient strength required for the joint portion.

  Further, in Comparative Examples 7 to 9, it is possible to maintain the strength that can be used even if it is out of the range of L <0.32D as long as the fusion bonding can be reliably performed. In general, as the fusion area increases, the reliability of the joint portion increases. However, since the insertion portion 2 is inserted into the receiving portion 4, resistance due to the molten resin is generated during fusion joining, and L is If the length is longer, the time until the fusion bonding is completed becomes longer, and the insertion resistance increases as the molten resin solidifies with the passage of time. Therefore, as the length L is increased, the increase rate of the insertion load increases. The probability of making a mistake increases. This is conspicuous for large-diameter joints, and in the case of an olefin-based resin joint of the present invention targeting 140 mm ≦ D ≦ 1000 mm, it should be within a range of 30% more than L having the minimum necessary fusion area. In this case, the insertion load does not increase so much, but if it exceeds 30%, the increase rate of the insertion load increases. Therefore, it is necessary that L <0.32D. Further, when L becomes longer, the volume of the joint 1 increases, so the cost of the material increases and the weight increases. Therefore, L <0.32D needs to be satisfied in order to keep the volume change range within about 20%. is there.

  From the above, if the dimension of L is in the range of 0.25D <L <0.32D, the insertion load at the time of fusion bonding can be suppressed to prevent a fusion error, and more reliable fusion bonding. It can be performed.

  In a socket-shaped polypropylene joint for joining polypropylene pipes 3 having a D of 140 mm, Z is 11.5 mm (Z = 0.082D), 15 mm (Z = 0.107D), 16.5 mm (Z = 0.118D) ), 19.5 mm (Z = 0.139D), 23 mm (Z = 0.164D), the results of the destructive water pressure test are shown in Example 4, Example 5, Example 6, Example 7, and Example 8. Are shown in Table 2.

  In the socket-shaped polypropylene joint 1 for joining the polypropylene pipes 3 with D of 180 mm, Z is 15 mm (Z = 0.083D), 16.5 mm (Z = 0.091D), 19.5 mm (Z = 0.0.0). 108D) and 23 mm (Z = 0.128D), the results of the fracture hydraulic pressure test are shown in Table 2 as Example 9, Example 10, Example 11, and Example 12, respectively.

  In a socket-shaped polypropylene joint 1 for joining polypropylene pipes 3 with D of 225 mm, Z is 16.5 mm (Z = 0.074D), 19.5 mm (Z = 0.087D), 23 mm (Z = 0. 096D) are shown in Table 2 as Example 13, Example 14, and Example 15, respectively.

  In the socket-shaped polypropylene joint 1 for joining the polypropylene pipes 3 with D of 140 mm, the fracture hydraulic pressure test results when Z is 7.5 mm (Z = 0.054D) are shown in Table 2 as Comparative Example 10. Show.

  Fracture water pressure test when D is 7.5 mm (Z = 0.042D) and 11.5 mm (Z = 0.064D) in a socket-shaped polypropylene joint 1 for joining polypropylene pipes 3 with D of 180 mm The results are shown in Table 2 as Comparative Example 11 and Comparative Example 12, respectively.

In a socket-shaped polypropylene joint 1 for joining polypropylene pipes 3 with D of 225 mm, Z is 7.5 mm (Z = 0.33D), 11.5 mm (Z = 0.051D), and 15 mm (Z = 0.67D). Table 2 shows the results of the fracture hydraulic pressure test as Comparative Example 13, Comparative Example 14, and Comparative Example 15, respectively.

  As can be seen from Table 2, from Comparative Examples 10 to 15, when 0.08D (1 + sin θ) <Z is not satisfied, the internal pressure applied to the inside of the pipe is the gap 12 formed between the end faces of the inserted pipe 3 due to the structure of the joint portion. Stress concentrates on the portion, and if the dimension of Z is small, the stress is concentrated and applied in the narrow gap 12, so that it cannot withstand the internal pressure and breaks. From Examples 4 to 15, if 0.08D (1 + sinθ) <Z, even if D is 140 mm, 180 mm, or 225 mm, if Z is greater than 0.08D, sufficient destruction Strength can be obtained.

  From the above, since it is a socket-shaped polypropylene joint, the bent pipe angle θ of the joint is 0 °. If 0.08D (1 + sinθ) <Z, the stress should be concentrated in the gap portion of the joint. In addition, the breaking strength can be maintained. In addition, if Z of a joint becomes long, the joint 1 becomes large and molding becomes difficult, leading to an increase in material cost and weight. Therefore, in order to suppress these, it is necessary that Z <0.13D (1 + sin θ). 0.08D (1 + sin θ) <Z <0.13D (1 + sin θ) is preferable.

  The present invention is made of polypropylene or polyethylene into which an insertion portion of a pipe joint having an outer diameter of 140 mm to 1000 mm is used for water distribution pipes, ultrapure water pipes, various chemical pipes, agricultural water pipes, steam pipes, various gas pipes, etc. The above-described excellent effects can be obtained by using as a joint having a receiving portion such as a socket, elbow, cheese or reducer.

It is a longitudinal cross-sectional view of the socket-shaped coupling which shows the 1st Example of this invention. It is a principal part expanded longitudinal cross-sectional view of FIG. It is a longitudinal cross-sectional view which shows the state at the time of a heating at the time of fusion-joining a joint and a pipe | tube. It is a longitudinal cross-sectional view which shows the state which inserted the pipe | tube into the joint by heat melting. It is a longitudinal cross-sectional view which shows the state which carried out the fusion splicing of the pipe | tube to the both opening parts of the coupling of FIG. It is a perspective view which shows the other Example of the protrusion provided in the outer periphery of the edge part of a coupling. It is a longitudinal cross-sectional view of a 90 ° elbow-shaped joint showing a second embodiment of the present invention. It is a longitudinal cross-sectional view which shows the state which carried out the fusion splicing of the pipe | tube to the both receiving port parts of the coupling of FIG. It is a longitudinal cross-sectional view which shows the conventional pipe joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Joint 2 ... Insertion part 3 ... Pipe 4 ... Receptacle part 5 ... Claw part 6 ... Clamp 7 ... Clamp 8 ... Step part 9 ... Projection part 10 ... Intermittent protrusion part 11 ... Chamfer part 12 ... Cavity 13 ... Heater 14 ... Joint 15 ... Fusion part 16 ... Insertion part 17 ... Pipe 18 ... Receiving part 19 ... Claw part 20 ... Chamfering part 21 ... Cavity 22 ... Bending part D ... Pipe outer diameter D1 ... Butt part outer diameter D2 ... Joint Outer diameter L ... Joint receiving port length Z ... Joint receiving port end to center straight portion length S ... Joint end surface to stepped portion θ ... Joint is a curved pipe joint Curved tube angle

Claims (2)

In the olefin resin joint having an inlet portion where the end of the olefin resin pipe and / or joint is inserted and heat-sealed,
D (mm): outer diameter of the insertion portion of the pipe and / or joint,
L (mm): length of the receiving portion of the joint,
Z (mm): the length of the straight portion from the end of the joint to the center of the joint (however, when the joint is a straight pipe, “center” means the midpoint between the two terminal ends of the joint, When the joint is a curved pipe, the “center” is defined as the intersection of the axes of the two receiving portions of the joint.
θ: bent pipe angle when the joint is a bent pipe joint,
When
1) 0.25D <L <0.32D
2) 0.08D (1 + sin θ) <Z
3) 140 ≦ D ≦ 1000
An olefin resin joint characterized by the above. At least two protrusions, intermittent protrusions, or flanges are provided on the outer periphery of at least one end of the joint so that when the joint is set on the fuser clamp, the joint hits the edge of the clamp. The olefin resin joint according to claim 1, wherein the olefin resin joint is fixed to the olefin resin joint.

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