Piping structure

Abstract

To provide a piping structure with improved heat resistance at an insertion port pipe part of a pipe joint with an insertion port.SOLUTION: A piping structure 10 comprises: an electric fusion cheese 12 (pipe joint with an insertion port) having a joint body 20 and a synthetic resin insertion port pipe part 32 with thickness of 4.6 mm or more and 7.0 mm or less; a synthetic resin pipe member 14 having the same outside diameter as the insertion port pipe part and thickness exceeding 7.0 mm; and an electric fusion socket 16 having electric fusion sockets 34 at both ends, and connecting the insertion port pipe part with the pipe member. Axial length L of an exposure part 32b of the insertion port pipe part is set to 70 mm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a piping structure, and in particular to a piping structure including, for example, a spigot pipe fitting having a fitting body and a spigot pipe portion made of synthetic resin and having a pipe thickness of 4.6 mm or more and 7.0 mm or less. [Background technology]

[0002] An example of this type of conventional piping structure is disclosed in Patent Document 1. The technology of Patent Document 1 relates to a fused pipe in which a first resin pipe and a second resin pipe are connected by fusion, and an inner circumferential bead is formed on the inner circumferential surface of the connection part between the first resin pipe and the second resin pipe, and the inner circumferential bead has a first convex portion on the first resin pipe side and a second convex portion on the second resin pipe side. The ratio of the maximum inner diameter at the end of the first resin pipe in the region where the inner circumferential bead is not formed to the maximum inner diameter at the end of the second resin pipe in the region where the inner circumferential bead is not formed is 1.02 or more and 1.15 or less, and the inner diameter of the first resin pipe at the maximum height position of the first convex portion is larger than the inner diameter of the second resin pipe at the maximum height position of the second convex portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-122516 A Summary of the Invention [Problem to be solved by the invention]

[0004] Piping is basically constructed by connecting pipe members with the same SDR, but in some cases, pipe members with different SDRs (i.e., the same outer diameter but different pipe thicknesses) are connected together, as in the technology of Patent Document 1. Note that SDR (Standard Dimension Ratio) is the value obtained by dividing the pipe outer diameter by the pipe thickness, and if this ratio is kept constant even if the pipe outer diameter changes, the pressure resistance will be the same.

[0005] Here, it is known that the heat resistance of piping depends on the pipe thickness of the plastic pipe section. For this reason, in the case of a piping structure formed by connecting pipe members with different SDRs, the heat resistance of the plastic pipe section with a large SDR (i.e., a small pipe thickness) is of concern. For example, in the case of a piping structure including a spigot pipe fitting such as an EF tee and a reducer, the heat resistance of the fitting body of the spigot pipe fitting is ensured because the pipe thickness is large. In addition, the heat resistance of the pipe member connected to the spigot pipe fitting can be ensured by using a pipe member with a small SDR (i.e., a large pipe thickness). However, since the spigot pipe section of the spigot pipe fitting is thinner than the fitting body, the heat resistance of this spigot pipe section is of concern. Therefore, a technology that can improve the heat resistance of this spigot pipe section is desired.

[0006] Therefore, a primary object of the present invention is to provide a novel piping structure.

[0007] Another object of the present invention is to provide a piping structure in which the heat resistance of the spigot pipe portion of a spigot pipe fitting is improved. [Means for solving the problem]

[0008] The first invention is a piping structure comprising a spigot pipe fitting having a fitting body and a synthetic resin spigot pipe section with a pipe thickness of 4.6 mm or more and 7.0 mm or less, a synthetic resin pipe member having the same outer diameter as the spigot pipe section and a pipe thickness of more than 7.0 mm, and an electric fusion socket having electric fusion receiving ports at both ends to connect the spigot pipe section and the pipe members, wherein the axial length of the exposed part of the spigot pipe section is 70 mm or less.

[0009] In a first invention, the piping structure includes a spigot pipe fitting, a pipe member, and an electric fusion socket. The spigot pipe fitting includes a fitting body and a spigot pipe part made of synthetic resin with a pipe thickness of 4.6 mm or more and 7.0 mm or less. The pipe member is made of synthetic resin, has the same outer diameter as the outer diameter of the spigot pipe part, and has a pipe thickness of more than 7.0 mm. The electric fusion socket has electric fusion receptacles at both ends and connects the spigot pipe part and the pipe member. The axial length of the exposed part of the spigot pipe part is set to 70 mm or less. In this way, by setting the axial length of the exposed part of the spigot pipe part to 70 mm or less, even if the spigot pipe part has a pipe thickness of 4.6 mm or more and 7.0 mm or less, the heat resistance of this part is improved, and heat resistance that can pass the light heat resistance test specified in Fire and Disaster Management Agency Notification No. 19 can be obtained.

[0010] According to the first invention, the axial length of the exposed part of the spigot pipe section is set to 70 mm or less, so that the heat resistance of the spigot pipe section and therefore the piping structure can be appropriately improved, and heat resistance sufficient to pass the light heat resistance test can be obtained.

[0011] A second invention is dependent on the first invention, and the axial length of the exposed portion is 1.5 times or less the inner diameter of the spigot pipe portion.

[0012] According to the second aspect of the present invention, the heat resistance of the spigot pipe part can be improved more appropriately.

[0013] A third invention is according to the first or second invention, and the axial length of the exposed portion is 3.0 to 12.0 times the pipe thickness of the spigot pipe portion.

[0014] According to the third aspect of the present invention, the heat resistance of the spigot pipe part can be improved more appropriately. Effect of the Invention

[0015] According to the present invention, the heat resistance of the spigot pipe portion of the spigot pipe fitting and therefore the piping structure can be appropriately improved, and heat resistance sufficient to pass the light heat resistance test can be obtained.

[0016] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings. [Brief description of the drawings]

[0017] [Figure 1] 1 is a plan view showing a piping structure according to an embodiment of the present invention; [Diagram 2] 2 is a cross-sectional view showing an electric fusion socket portion of the piping structure of FIG. 1. [Diagram 3] FIG. 11 is a plan view showing a piping structure according to another embodiment of the present invention. [Figure 4] FIG. 11 is a plan view showing a piping structure according to still another embodiment of the present invention. [Diagram 5] FIG. 11 is a plan view showing a piping structure according to still another embodiment of the present invention. [Figure 6] FIG. 11 is a plan view showing a piping structure according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Referring to FIG. 1, a piping structure 10 which is one embodiment of the present invention comprises an electric fusion tee 12 (hereinafter referred to as "EF tee 12"), a pipe member 14, and an electric fusion socket 16 (hereinafter referred to as "EF socket 16"), etc., and is constructed by fusion joining these together.

[0019] The use and nominal diameter of the piping structure 10 are not particularly limited, but since the piping structure 10 has improved heat resistance as described below, it is suitable for use as a fire piping for a sprinkler system or a fire hydrant system. The nominal diameter (inner diameter) of the piping structure 10 is, for example, 40 mm to 300 mm, and the following description will be given by taking as an example the piping structure 10 at a branching portion where a pipe with a nominal diameter of 75 mm branches into a pipe with a nominal diameter of 50 mm. The SDR (Standard Dimension Ratio) described below is the value obtained by dividing the pipe outer diameter by the pipe thickness, and the pressure resistance is the same if this ratio is constant even if the pipe outer diameter changes.

[0020] 1 and 2, the piping structure 10 includes an EF tee 12, a pipe member 14, an EF socket 16, etc. Each of the EF tee 12, the pipe member 14, and the EF socket 16 is made of a polyolefin-based synthetic resin such as polyethylene or polybutene. In this embodiment, they are made of polyethylene (specifically, high-density polyethylene).

[0021] The EF tee 12 is an example of a spigot-equipped pipe joint, and includes a joint body 20 and a branch pipe section 22. The joint body 20 has electric fusion sockets 24 at both ends for receiving the ends of a pipe member 18 made of synthetic resin (polyethylene). A heating wire (not shown) is embedded in the vicinity of the inner surface of the electric fusion socket 24 so as to extend in a spiral shape. Both ends of the heating wire are connected to a power supply connection terminal 26 formed to protrude from the top of the electric fusion socket 24. When the power supply connection terminal 26 is connected to a power supply and an electric current is passed through the heating wire, the resin at the joint surface between the electric fusion socket 24 and the pipe member 18 is heated and melted by the heat generated, and the electric fusion socket 24 and the pipe member 18 are fused and joined. In this embodiment, the nominal diameter of the joint body 20 and the pipe member 18 connected to the joint body 20 is 75 mm. The outer diameter of the pipe member 18 is, for example, 90 mm, and the pipe thickness is, for example, 8.2 mm.

[0022] On the other hand, the branch pipe section 22 is formed protruding from the center of the joint body 20. In this embodiment, the nominal diameter of the branch pipe section 22 is 50 mm. The branch pipe section 22 includes a base end section 30 formed on the periphery of the branch port formed in the joint body 20, and a spigot pipe section 32 extending in the branching direction from the base end section 30. The base end section 30 is thicker than the spigot pipe section 32, and in this embodiment, the outer circumferential surface of the branch pipe section 22 is stepped down at the connecting portion between the base end section 30 and the spigot pipe section 32. The outer diameter of the spigot pipe section 32 is, for example, 63 mm. In this embodiment, the spigot pipe section 32 has a pipe thickness specification of SDR11, and the pipe thickness t1 is, for example, 5.8 mm. The inner diameter d1 of the spigot pipe section 32 is, for example, 51 mm.

[0023] The pipe member 14 may be, for example, a plain end straight pipe. The outer diameter of the pipe member 14 is the same as the outer diameter of the spigot pipe portion 32, for example, 63 mm. The pipe thickness t2 of the pipe member 14 is set to be larger than the pipe thickness t1 of the spigot pipe portion 32, specifically, set to be greater than 7.0 mm. In this embodiment, the pipe member 14 has a pipe thickness specification of SDR9, and the pipe thickness t2 is, for example, 7.1 mm. The inner diameter of the pipe member 14 is, for example, 49 mm.

[0024] The EF socket 16 has electric fusion receptacles 34 at both ends for receiving the respective ends of the spigot pipe section 32 of the EF tee 12 and the pipe member 14. As with the electric fusion receptacle 24 of the EF tee 12, an electric heating wire (not shown) is embedded in the vicinity of the inner surface of the electric fusion receptacle 34 so as to extend in a spiral shape. Both ends of the electric heating wire are connected to a power supply connection terminal 36 formed to protrude from the top of the electric fusion receptacle 34. When the power supply connection terminal 36 is connected to a power supply and an electric current is passed through the electric heating wire, the heat generated heats and melts the resin at the joint surfaces between the electric fusion receptacle 34 and the spigot pipe section 32 and the pipe member 14, and the spigot pipe section 32 and the pipe member 14 are fusion-joined to the electric fusion receptacle 34.

[0025] In such a piping structure 10, the joint body 20 of the EF tee 12 (pipe joint with spigot) and the base end 30 of the branch pipe section 22, and the part where the EF socket 16 are piped, have a large pipe thickness, so that heat resistance is ensured. Also, for the part where the pipe member 14 is piped, by using a pipe member 14 with a large pipe thickness (small SDR), heat resistance can be ensured. As a result of intensive research by the inventors, it was found that by having a pipe thickness of more than 7.0 mm, heat resistance that can pass the light heat resistance test specified in Fire and Disaster Management Agency Notification No. 19 (Standards for synthetic resin pipes and pipe joints) can be ensured. That is, by setting the pipe thickness t2 of the pipe member 14 to a value exceeding 7.0 mm as described above, heat resistance can be ensured. In addition, by setting the pipe member 18 connected to the joint body 20 of the EF tee 12 to a pipe thickness of more than 7.0 mm, heat resistance can also be ensured.

[0026] Furthermore, in the portion where the spigot pipe section 32 of the EF tee 12 is piped, the insertion section 32a (joint section) that is inserted into the electric fusion receptacle 34 of the EF socket 16 has a large pipe thickness, ensuring heat resistance. However, the exposed section 32b that is exposed to the outside on the base end 30 side of the spigot pipe section 32 has a smaller pipe thickness than other sections, raising concerns about its heat resistance. The heat resistance of this exposed section 32b can also be improved by increasing the pipe thickness t1 of the spigot pipe section 32, but this requires a change in the design of the entire EF tee 12, which increases costs.

[0027] As a result of further intensive study by the inventors, it was found that even if the pipe thickness t1 of the spigot pipe portion 32 (exposed portion 32b) is 7.0 mm or less, if the pipe thickness t1 is 4.6 mm or more, heat resistance (heat resistance strength) sufficient to pass the light heat resistance test can be obtained by setting the axial length L of the exposed portion 32b to 70 mm or less. In other words, it was found that it is good to set the axial length L of the exposed portion 32b of the spigot pipe portion 32 to 70 mm or less. In this embodiment, the axial length L of the exposed portion 32b is set to 35 mm.

[0028] In this way, by setting the axial length L of the exposed portion 32b of the spigot pipe portion 32 to 70 mm or less, even if the spigot pipe portion 32 has a pipe thickness of 4.6 mm or more and 7.0 mm or less, the heat resistance of this portion is improved, and the spigot pipe portion 32 (and therefore the piping structure 10) can obtain heat resistance sufficient to pass a light heat resistance test. Furthermore, by setting the axial length L of the exposed portion 32b to 70 mm or less, the pressure resistance strength (pressure resistance) of the spigot pipe portion 32 at room temperature can also be improved.

[0029] Furthermore, it is preferable to set the axial length L of exposed portion 32b to 1.5 times or less the inner diameter d1 of spigot pipe portion 32, that is, to satisfy the condition L / d1≦1.5, while satisfying the condition that the axial length L of exposed portion 32b is 70 mm or less. This is because the heat resistance of spigot pipe portion 32 can be improved more appropriately.

[0030] Furthermore, it is preferable to set the axial length L of the exposed portion 32b to 3.0 to 12.0 times the pipe thickness t1 of the spigot pipe portion 32, in other words, to satisfy the condition 3.0≦L / t1≦12.0. This is because the heat resistance of the spigot pipe portion 32 can be improved more appropriately.

[0031] As described above, according to this embodiment, the axial length L of the exposed portion 32b of the spigot pipe portion 32 is set to 70 mm or less, so that the heat resistance of the spigot pipe portion 32 and therefore the piping structure 10 can be appropriately improved, and heat resistance sufficient to pass the light heat resistance test can be obtained.

[0032] It should be noted that the specific configuration of the piping structure 10 described above, that is, the specific configurations of the EF tee 12 (spigot pipe joint), the pipe member 14, and the EF socket 16 are merely examples and can be modified as appropriate.

[0033] For example, as shown in the embodiment in FIG. 3, the spigot pipe section 32 of the EF tee 12 may be formed by butt welding. That is, the exposed section 32b of the spigot pipe section 32 may include a bead section 32c. The outer circumferential surface of the branch pipe section 22 does not necessarily have to be stepped at the connection between the base end section 30 and the spigot pipe section 32, and may be formed into a smoothly curved surface. In this embodiment, the outer diameter of the spigot pipe section 32 is 63 mm. The pipe thickness t1 of the spigot pipe section 32 is, for example, 5.8 mm, and the inner diameter d1 is, for example, 51 mm. The axial length L of the exposed section 32b is, for example, 45 mm.

[0034] As shown in the embodiment in FIG. 4, the EF socket 16 may have a clamp portion 40 provided so as to protrude from the tip surface of the electric fusion socket 34. In this case, the heat resistance of the part of the spigot pipe portion 32 that is clamped by the clamp portion 40 (covered part) is improved by the clamp portion 40. The exposed part 32b of the spigot pipe portion 32 is the part from the base end of the spigot pipe portion 32 to the end surface of the electric fusion socket 34. In this embodiment, the outer diameter of the spigot pipe portion 32 is 50 mm. The pipe thickness t1 of the spigot pipe portion 32 is, for example, 4.6 mm, and the inner diameter d1 is, for example, 41 mm. The axial length L of the exposed part 32b is, for example, 14 mm.

[0035] In the embodiment shown in Figures 3 and 4, as in the embodiment shown in Figure 1, the axial length L of the exposed portion 32b of the spigot pipe section 32 is set to 70 mm or less, so that the heat resistance of the spigot pipe section 32 and therefore the piping structure 10 can be appropriately improved and heat resistance sufficient to pass the light heat resistance test can be obtained.

[0036] Furthermore, in the above-mentioned embodiment, an EF tee was shown as an example of a spigot pipe joint, but the configuration of the portion (joint body) other than the spigot pipe portion of the spigot pipe joint is not particularly limited. For example, as in the embodiment shown in FIG. 5, the spigot pipe joint provided in the piping structure 10 may be a reducer 50. Simply put, the reducer 50 includes a joint body 52 and a spigot pipe portion 54. The joint body 52 includes a large diameter portion 56 having a larger diameter than the spigot pipe portion 54, and a tapered portion 58 whose diameter decreases from the large diameter portion 56 toward the spigot pipe portion 54 side. The pipe member 14 is connected to the end of the spigot pipe portion 54 of this reducer 50 (spigot pipe joint) via the EF socket 16. On the other hand, the pipe member 62 is connected to the end of the large diameter portion 56 of the reducer 50 via, for example, an EF socket 60. The pipe thickness of the joint body 52 (large diameter portion 56 and tapered portion 58) of the reducer 50 is larger than the pipe thickness t1 of the spigot pipe portion 54, and is, for example, 8.2 mm. In this embodiment, the outer diameter of the spigot pipe portion 54 is 63 mm. The pipe thickness t1 of the spigot pipe portion 54 is, for example, 5.8 mm, and its inner diameter d1 is, for example, 51 mm. Furthermore, the axial length L of the exposed portion 54a is, for example, 66 mm.

[0037] In the embodiment shown in FIG. 5, as in the embodiment shown in FIG. 1, the axial length L of the exposed portion 54a of the spigot pipe portion 54 is set to 70 mm or less, so that the heat resistance of the spigot pipe portion 54 and therefore the piping structure 10 can be appropriately improved and heat resistance sufficient to pass the light heat resistance test can be obtained.

[0038] Furthermore, as in the embodiment shown in Fig. 6, the spigot pipe joint may be a conversion joint 70 for connecting a metal pipe member (not shown) such as a steel pipe and a valve to a synthetic resin pipe member 14 such as a polyethylene pipe. Briefly, the conversion joint 70 includes a metal joint body 72 having a first connecting portion 80 and a second connecting portion 82, a synthetic resin spigot pipe portion 74 having one end fitted onto the first connecting portion 80, and a metal ring 76 fitted onto one end of the spigot pipe portion 74. The pipe member 14 is connected to the other end of the spigot pipe portion 74 via an EF socket 16. Meanwhile, a metal pipe member such as a steel pipe and a valve is connected to the second connecting portion 82 of the joint body 72.

[0039] In this embodiment, the spigot pipe portion 74 is made of a polyethylene short pipe of SDR11, and the pipe member 14 is made of a polyethylene pipe of SDR9. The outer diameters of the spigot pipe portion 74 and the pipe member 14 are, for example, 125 mm. The pipe thickness t1 of the spigot pipe portion 74 is, for example, 11.4 mm, and the pipe thickness t2 of the pipe member 14 is, for example, 14.0 mm. The inner diameter d1 of the pipe member 14 is, for example, 102.2 mm, and the inner diameter d2 of the pipe member 14 is, for example, 97.0 mm. The axial length L of the exposed portion 74a is, for example, 66 mm.

[0040] In the embodiment shown in FIG. 6, as in the embodiment shown in FIG. 1, the axial length L of the exposed portion 74a of the spigot pipe portion 74 is set to 70 mm or less, so that the heat resistance of the spigot pipe portion 74 and therefore the piping structure 10 can be appropriately improved and heat resistance sufficient to pass the light heat resistance test can be obtained.

[0041] It should be noted that the specific values ​​such as dimensions and specific configurations given above are merely examples and can be changed as appropriate according to the needs of product specifications, etc. [Explanation of symbols]

[0042] 10...Piping structure 12... Electric fusion tee (pipe joint with spigot) 14...Pipe member 16... Electric fusion socket 20 … Joint body 22 …Branch pipe section 32... Socket pipe part 32b...Exposed part 34... Electric fusion socket 50...Reducer (pipe joint with spigot) 52 … Joint body 54 … Socket pipe part 54a...Exposed part 70...Conversion joint (pipe joint with spigot) 72 … Joint body 74 … Socket pipe part 74a...Exposed part 76 ... Ring

Claims

1. A pipe joint with a spigot having a joint body and a spigot pipe part made of a synthetic resin and having a pipe thickness of 4.6 mm or more and 7.0 mm or less; A synthetic resin pipe member having the same outer diameter as the spigot pipe portion and a pipe thickness of more than 7.0 mm; and an electric fusion socket having electric fusion receiving ports at both ends and connecting the spigot pipe portion and the pipe member; A piping structure in which the axial length of the exposed portion of the spigot pipe is 70 mm or less.

2. 2. The piping structure according to claim 1, wherein the axial length of said exposed portion is 1.5 times or less the inner diameter of said spigot pipe portion.

3. 3. The piping structure according to claim 1, wherein the axial length of the exposed portion is 3.0 to 12.0 times the pipe thickness of the spigot pipe portion.

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