Resin pipe connection device

Abstract

To improve strength of a connection device of a resin pipe.SOLUTION: A connection device 5 includes an upper split body 10, a lower split body 20, hinge means H for rotatably coupling one end portions of the split bodies 10, 20, and fastening means 30 for fastening the other end portions of the split bodies 10, 20 so as to come close to each other. Fitting grooves 12, 22 are formed on inner peripheries of body portions 11, 21 of the split bodies 10, 20. At the time of fastening, tapered surfaces 12x, 22x of the fitting grooves 12, 22 are abutted to tapered surfaces 1y, 2y of flange portions 1a, 2a of resin pipes 1, 2, and thereby, flanges 1a, 2a of the resin pipes 1, 2 are abutted with each other. The split bodies 10, 20 mainly consist of glass fiber reinforced nylon. In the first and the second split bodies 10, 20, a hydrophobic layer made of an acrylic resin, an ethylene-vinyl acetate resin, an urethane resin, etc., is formed on inner peripheries coming into contact with the resin pipes 1a, 2a (including inner surfaces of the fitting grooves 12, 22) and end facing surfaces.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a device for connecting two plastic pipes each having a flange at one end. [Background technology]

[0002] When it is necessary to connect plastic pipes without welding at the construction site for water supply piping, plastic pipes with flanges at the end are manufactured in the factory by butt welding a short pipe with a flange to a long plastic pipe body. The flange has a butt joint surface at the tip that is perpendicular to the axis of the plastic pipe and a tapered surface on the opposite side. At the construction site, a connecting device is used to connect the flanges of the two plastic pipes by butting them together.

[0003] As shown in Patent Documents 1 and 2, the connection device includes a pair of half-split segments, hinge means for rotatably connecting one end of the pair of segments to each other, and fastening means for tightening the other end of the pair of segments so as to bring the other end of the pair of segments closer to each other. A semicircular mating groove is formed on the inner periphery of each of the pair of segments. Tapered surfaces are formed on both sides of the mating groove at a taper angle equal to the tapered surface of the flange portion of the plastic pipe.

[0004] To briefly explain the process of connecting plastic pipes using the connecting device, the pair of segments is opened, and the flanges of the two plastic pipes are placed in the mating grooves of the lower segment. Next, the upper segment is rotated in the closing direction around the hinge means, loosely fitting the flanges of the two plastic pipes into the mating grooves. Finally, when the segments are tightened using the tightening means, the tapered surfaces on both sides of the mating grooves come into contact with the tapered surfaces of the flanges of the two plastic pipes, and the tightening force is converted into an axial force that moves the flanges of the two plastic pipes closer together. As a result, the two plastic pipes are connected with the butting surfaces of the flanges touching each other. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5740123 [Patent Document 2] Patent Publication No. 2021-50789 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 2, strength is increased by using glass fiber reinforced resin as the main raw material of the divided bodies. When glass fiber reinforced polypropylene (GFPP) is used as the main raw material for the glass fiber reinforced resin, thermal degradation occurs when high-temperature water flows through the piping, resulting in a decrease in strength. When glass fiber reinforced nylon (GFPA) is used as the main raw material for the segments, it has high strength and does not lose strength due to thermal degradation. However, nylon is water-absorbent, which causes a loss of strength, making it difficult to use for water supply piping. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides: A resin pipe connecting device in which annular flange portions at the pipe ends of two resin pipes are butted against each other and which includes first and second divided bodies that cover the flange portions from the outer periphery, The first and second divided bodies are made mainly of glass fiber reinforced nylon, and It is characterized by having a hydrophobic layer on the inner surface.

[0008] According to the above-mentioned configuration, the first and second division bodies are made of glass fiber reinforced nylon as the main material, which increases the strength of the body, and prevents the strength from decreasing due to thermal degradation even when high-temperature water flows through the resin pipe. split body A hydrophobic layer was formed on the inner surface of So, It can prevent water absorption in glass fiber reinforced nylon, and reduce the loss of strength due to water absorption. Not invited. As a result, it can be used as a connecting device for water supply piping.

[0009] Preferably, the inner periphery of the first and second divided bodies has cylindrical pipe portion pressing surfaces adjacent to both axial sides of the fitting groove, and in the tightened state, the pipe portion pressing surfaces press the outer peripheral surface of the pipe portion adjacent to the flange portion of the plastic pipe, and the hydrophobic layer is also formed on the pipe portion pressing surfaces. According to the above-mentioned configuration, water absorption by the glass fiber reinforced nylon can be prevented even on the pipe pressing surface which may come into contact with water.

[0010] Preferably, the hydrophobic layer is also formed on the opposing surfaces of the circumferential ends of the first and second divided bodies. According to the above-described configuration, water absorption by the glass fiber reinforced nylon can be prevented even at the end-facing surfaces that may come into contact with water.

[0011] Preferably, the hydrophobic layer is formed over the entire outer surfaces of the first and second divided bodies. According to this configuration, the glass fibers protruding from the outer surfaces of the first and second segments can be covered, improving the appearance.

[0012] Preferably, the hydrophobic layer is provided as a primer, and a paint is applied thereon. According to the above-mentioned configuration, the appearance can be further improved by applying paint.

[0013] The hydrophobic layer contains at least one of an acrylic resin, an ethylene vinyl acetate resin, and a urethane resin. The hydrophobic layer has a thickness of 10 μm or more. [Effects of the Invention]

[0014] According to the present invention, high strength can be maintained even when used to connect resin pipes that make up water supply piping. [Brief explanation of the drawings]

[0015] [Figure 1]1 is a perspective view showing a resin pipe connecting device according to an embodiment of the present invention in a state where the connection of the resin pipe has been completed, with the connecting device and the resin pipe partially cut away. FIG. [Figure 2] 1 is a perspective view showing a pair of upper and lower divided bodies of the connection device in a separated state, in which the pair of divided bodies are each cut in half in the width direction and are viewed from different directions. FIG. [Figure 3] FIG. 4 is a cross-sectional view showing the pair of divided bodies in a separated state. [Figure 4] 4A and 4B are cross-sectional views sequentially showing the steps of connecting a resin pipe using the connecting device, where FIG. 4A shows a state during the connecting step, and FIG. 4B shows a state after the connecting step is completed, with the resin pipe omitted. [Figure 5] 5A and 5B are longitudinal cross-sectional views sequentially illustrating a process of connecting a resin pipe using the connecting device, where FIG. 5A shows a state during the connecting process, and FIG. 5B shows a state after the connecting process is completed. [Figure 6] FIG. 4 is an enlarged cross-sectional view of a hydrophobic layer formed on the divided body. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Resin pipe structure First, referring to Figures 1 and 5, we will explain the plastic pipes 1 and 2 of the water supply piping to be connected. The plastic pipes 1 and 2 are made of a resin such as polyethylene and have annular flange portions 1a and 2a at one end. The tip surfaces of the flange portions 1a and 2a form mating surfaces 1x and 2x that are perpendicular to the axis L, and the surfaces on the opposite sides form tapered surfaces 1y and 2y. An annular groove 1z is formed in the mating surface 1x of the flange portion 1a of one of the plastic pipes 1, and an O-ring 3 is fitted into this annular groove 1z. The resin pipes 1 and 2 are manufactured by butt welding a short pipe having the flange portions 1a and 2a to a long resin pipe body.

[0017] A short cylindrical incore 4 is disposed on the inner periphery of one end of each of the plastic pipes 1 and 2. The incore 4 is made of stainless steel such as SUS304, and has an annular flange 4a that protrudes radially and outward at one end. This flange 4a engages with annular recesses 1b and 2b formed on the inner periphery of the tip of each of the plastic pipes 1 and 2, thereby attaching the incore 4 to the plastic pipes 1 and 2 with its axial movement restricted. Because the flange 4a is housed in the recesses 1b and 2b, it does not interfere with the butting of the flanges 1a and 2a, which will be described later.

[0018] Configuration of the connected device Next, we will explain the connection device 5 for connecting the resin pipes 1 and 2. The connection device 5 has a pair of upper and lower division bodies, namely, an upper division body 10 (first division body) and a lower division body 20 (second division body). The division bodies 10 and 20 are made mainly of glass fiber reinforced nylon and have approximately semi-cylindrical main body portions 11 and 21, respectively.

[0019] The main body portions 11, 21 of the segments 10, 20 have a circumferential dimension slightly shorter than that of a complete semicylinder. That is, as shown in Fig. 3, both circumferential end faces 11x, 11y (end-facing surfaces) of the main body portion 11 of the upper segment 10 are slightly set back from a plane P passing through the radial center C of the inner periphery of the main body portion 11 and are parallel to this plane P. Similarly, the circumferential end faces 21x, 21y (end-facing surfaces) of the main body portion 21 of the lower segment 20 are slightly set back from a plane P' passing through the radial center C' of the inner periphery of the main body portion 21 and are parallel to this plane P'.

[0020] The inner periphery of the main body 11, 21 of the divided body 10, 20 has a fitting groove 12, 22 extending in a roughly semicircular shape in the circumferential direction and semicylindrical pipe portion pressing surfaces 13, 23 adjacent to both axial sides of the fitting groove 12, 22. The diameter of the pipe portion pressing surfaces 13, 23 is equal to the outer diameter of the pipe portion of the resin pipe 1, 2 (excluding the flange portions 1a, 2a). The inner surfaces of the fitting grooves 12, 22 have tapered surfaces 12x, 22x on both sides and have bottom surfaces 12y, 22y in the center that form semi-cylindrical surfaces with a diameter larger than that of the pipe portion pressing surfaces 13, 23. The taper angle of the tapered surfaces 12x, 22x is the same as that of the tapered surfaces 1y, 2y of the flange portions 1a, 2a of the resin pipes 1, 2. The diameter of the bottom surfaces 12y, 22y is the same as the outer diameter of the flange portions 1a, 2a. The cross-sectional shape of the fitting grooves 12, 22 is approximately the same as that of the flange portions 1a, 2a when the butting surfaces 1x, 2x of the flange portions 1a, 2a are in contact, as will be described later.

[0021] An engaging portion 15 is provided integrally with the main body 11 at one circumferential end of the main body 11 of the upper half body 10. This engaging portion 15 has a protruding portion 15a that protrudes radially outward from one end of the main body 11, and an extending portion 15b that extends downward (toward the lower half body 20) from the tip of this protruding portion 15a, beyond the end face 11x, and perpendicular to the end face 11x. The lower surface of the protruding portion 15a forms an end-facing surface 15x that is flush with the end face 11x of the main body 11.

[0022] An engagement hole 16 is formed in the engagement portion 15 of the upper half body 10. This engagement hole 16 has a main hole portion 16a formed in the extension portion 15b and penetrating in the radial direction, and an escape recess portion 16b formed in the protrusion portion 15a and connected to the main hole portion 16a. The main hole portion 16a is substantially rectangular and occupies a portion between a lower surface 16x of the engagement hole 16 and an imaginary extension of the end opposing surface 15x. This lower surface 16x serves as a load-receiving surface, as will be described later. The relief recess 16b is located above the imaginary extension plane of the end opposing surface 15x (opposite the lower divided body 20) and is open only radially outward. The horizontal dimension of the relief recess 16b is equal to the horizontal dimension of the main hole portion 16a.

[0023] An engagement protrusion 25 extending radially outward is formed integrally with the main body 21 at one circumferential end of the main body 21 of the lower half body 20. The cross section of the engagement protrusion 25 is rectangular, and its upper surface forms an end-facing surface 25x that is flush with the end surface 21x of the main body 21. The vertical and horizontal dimensions of the engagement protrusion 25 are slightly shorter than the vertical and horizontal dimensions of the main hole portion 16a of the engagement hole 16 in the upper half body 10. As will be described later, the engagement protrusion 25 of the lower division body 20 is inserted into the engagement hole 16 of the upper division body 10 to form a hinge means H. This hinge means H connects the upper division body 10 to the lower division body 20 so as to be rotatable relative to each other along a plane perpendicular to the axis L of the resin pipes 1 and 2.

[0024] Support portions 18, 28 protruding radially outward are formed integrally with the main body portions 11, 21 at the other circumferential ends of the main body portions 11, 21 of the segments 10, 20. The support portions 18, 28 have end-facing surfaces 18x, 28x that are flush with the end faces 11y, 21y of the main body portions 11, 21. Through holes 18a, 28a are formed in the support portions 18, 28. A pair of anti-rotation projections 29 are formed on the underside of the support portion 28 and positioned on both sides of the through hole 28a. As shown in FIG. 4(B), fastening means 30 for fastening the support parts 18 and 28 together includes a bolt 31 and a nut 32.

[0025] Resin pipe connection process using a connecting device The process of connecting the plastic pipes 1 and 2 using the connecting device 5 will now be described. As shown in Figures 4(A) and 5(A), first, the flange portions 1a and 2a of the plastic pipes 1 and 2 are placed on the lower divided body 20 with the O-ring 3 brought close enough to lightly contact the mating surface 2x of the plastic pipe 2. The flange portions 1a and 2a are aligned with the fitting groove 22, and a portion of them is received in the fitting groove 22.

[0026] Next, the upper divisional body 10 is moved laterally toward the lower divisional body 20 while still in an inclined position, and the engaging protrusion 25 is inserted into the engaging hole 16 of the engaging portion 15. At this time, part of the tip of the engaging protrusion 25 comes out of the main hole portion 16a of the engaging hole 16, but can be received in the relief recess 16b.

[0027] Next, by rotating the upper divisional body 10 around the fulcrum F (the point where one end of the load-receiving surface 16x contacts the underside of the engaging protrusion 25) so as to move it closer to the lower divisional body 20, the support portion 18 of the upper divisional body 10 approaches and faces the support portion 28 of the lower divisional body 20. In this state, parts of the flange portions 1a, 2a are also accommodated in the fitting groove 12 of the upper divisional body 10. In addition, the engaging protrusion 25 of the lower divisional body 20 fits into the main hole portion 16a of the engaging hole 16 of the upper divisional body 10.

[0028] Next, with the nut 32 non-rotatably fitted between the pair of anti-rotation projections 29, as shown in FIG. 4(B), the bolt 31 is passed through the through-holes 18a, 28a of the support portions 18, 28 of the segments 10, 20, threaded onto the nut 32, and then turned in the tightening direction. This clamps the flanges 1a, 2a of the resin pipes 1, 2 between the lower segment 20 and the upper segment 10. This tightening force is converted into an axial force that moves the flanges 1a, 2a toward each other by the action of the tapered surfaces 12x, 22x on both sides of the fitting grooves 12, 22 and the tapered surfaces 1y, 2y of the flanges 1a, 2a. As a result, as shown in FIG. 5(B), the butting surfaces 1x, 2x of the flanges 1a, 2a come into surface contact with each other due to the elastic deformation of the O-ring 3. This completes the connection process.

[0029] Tightening the bolt 31 brings the support parts 18, 28 closer to each other, and a force acts in the direction of moving the opposite sides apart. As a result, the engaging protrusion 25 strongly hits the load-receiving surface 16x of the engaging hole 16 of the engaging part 15. This allows the lower half body 20 and the upper half body 10 to tightly fasten the flange parts 1a, 2a together.

[0030] In the fastened state, the inner surfaces of the fitting grooves 12, 22, i.e., the tapered surfaces 12x, 22x and the bottom surfaces 12y, 22y, are in contact with the tapered surfaces 1y, 2y and outer peripheral surfaces of the flange portions 1a, 2a of the resin pipes 1, 2, respectively, and the pipe portion pressing surfaces 13, 23 are in contact with the outer peripheral surfaces of the pipe portions adjacent to the flange portions 1a, 2a of the resin pipes 1, 2. Also, in this fastened state, the end surfaces 11x, 11y of the main body portion 11 of the upper division body 10 and the end surfaces 21x, 21y of the main body portion 21 of the lower division body 20 are closely opposed to each other, the engaging portion 15 of the hinge means H and the end-facing surfaces 15x, 25x of the engaging projection 15 are closely opposed to each other, and the end-facing surfaces 18x, 28x of the supporting portions 18, 28 are closely opposed to each other.

[0031] Formation of a hydrophobic layer The segments 10 and 20 are injection-molded products made primarily of glass-fiber-reinforced nylon. Therefore, they have high strength and can maintain their high strength without thermal degradation even when high-temperature water flows through the water supply pipe. However, nylon is water-absorbent, which can lead to a decrease in strength due to water absorption. For example, when nylon absorbs approximately 1 to 5% water, its strength decreases by up to 50% compared to when it is bone-dry. Therefore, in this embodiment, a hydrophobic layer 50 (see FIG. 6) is formed on the surfaces of the divided bodies 10, 20 that may come into contact with water if a small amount of water leaks from the joints of the resin pipes 1, 2. This hydrophobic layer 50 is formed by spraying a resin containing at least one of an acrylic resin, an ethylene vinyl acetate resin, and a urethane resin. The hydrophobic layer 50 has a thickness of 5 to 30 μm, and more preferably a thickness of 10 to 30 μm.

[0032] In this embodiment, the hydrophobic layer 50 is formed on the entire inner periphery of the divided bodies 10, 20 that contacts the resin pipes 1, 2 and on the surfaces that are close to and face each other. The inner periphery of each divided body 10, 20 includes the inner surface of the fitting groove 12, 22 (that is, the tapered surface 12x, 22x and the bottom surface 12y, 22y) and the pipe portion pressing surface 13, . The adjacent opposing surfaces of the divided bodies 10 and 20 include end surfaces 11x, 11y, 21x, and 21y of the main body portions 11 and 21, and end opposing surfaces 15x, 25x, 18x, and 28x.

[0033] As described above, the hydrophobic layer 50 is formed on the inner periphery and opposing surfaces of the divided bodies 10, 20, thereby preventing the glass fiber reinforced nylon of the divided bodies 10, 20 from absorbing water, thereby preventing a decrease in strength due to water absorption and maintaining high strength.

[0034] experiment Two types of dumbbell-shaped test pieces made of glass fiber reinforced nylon of the same dimensions were prepared. Test piece (1) had the above-mentioned hydrophobic layer formed to a thickness of 10 to 20 μm, while test piece (2) had no hydrophobic layer formed. Both test pieces were subjected to creep tests in warm water at 80°C, and the rupture times were compared, with the results shown in Table 1 below. Table 1 confirms the effect of the hydrophobic layer. [Table 1]

[0035] The hydrophobic layer 50 may be formed only on the inner surfaces of the fitting grooves 12, 22 that are most likely to come into contact with water. The hydrophobic layer 50 may also be formed on the entire outer surface (exposed surface) of the segments 10 and 20. When glass fiber reinforced nylon is injection molded, minute fibers protrude from the outer surface of the molded product, marring the appearance. However, by covering these fibers with the hydrophobic layer 50, the appearance can be improved.

[0036] When the hydrophobic layer 50 is formed on the entire outer surface of the divided bodies 10, 20, the appearance can be further improved by using the hydrophobic layer as a primer and applying paint 60 (see Figure 6) over the entire surface on top of this primer.

[0037] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the hinge device may include a shaft member, a link, etc. that are separate from the first and second halves. The fastening means can also be modified in various ways. [Industrial Applicability]

[0038] The present invention can be applied to a device for connecting a resin pipe having a flange portion at the end. [Explanation of symbols]

[0039] 1, 2 Resin pipe 1a, 2a flange 1x, 2x butt faces 1y, 2y tapered surface 5 Connecting Devices 10 Upper division body (first division body) 20 Lower divided body (second divided body) 11x, 11y, 21x, 21y End faces of the main body (opposite end faces) 12, 22 Fitting groove 12x, 22x tapered surface 12y, 22y bottom 13, 23 Pipe holding surface 15x, 25x, 18x, 28x End facing surface 30 Fastening means 50 Hydrophobic layer 60 paint H Hinge Means

Claims

1. The pipe end of each of the two resin pipes is butted against annular flange portions, and first and second divided bodies are provided to cover the flange portions from the outer periphery thereof. The first and second divided bodies are made mainly of glass fiber reinforced nylon, The resin pipe connecting device has a hydrophobic layer on the inner surface of the first and second divided bodies.

2. 2. The resin pipe connecting device according to claim 1, wherein the first and second divided bodies are also provided with hydrophobic layers on their opposing surfaces.

3. 3. The resin pipe connecting device according to claim 1, wherein the hydrophobic layer is also formed on the outer surfaces of the first and second divided bodies.

4. The resin pipe connecting device according to claim 1 , wherein the hydrophobic layer is a primer.

5. The resin pipe connecting device according to claim 1 , wherein the hydrophobic layer contains at least one of an acrylic resin, an ethylene vinyl acetate resin, and a urethane resin.

6. The resin pipe connecting device according to claim 1 , wherein the hydrophobic layer has a thickness of 5 μm or more.

7. A water supply pipe comprising: the resin pipe connecting device according to any one of claims 1 to 6; and a resin pipe connected to the resin pipe connecting device.

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