Drain pipe fittings

Abstract

This invention provides a joint for drainage pipes that has excellent heat resistance and chemical resistance, as well as excellent workability. [Solution] The drain pipe fitting 10 of the present invention is a drain pipe fitting made of polypropylene resin, having a socket 12 on at least one side, with a rubber ring 20 fitted on the inner surface of the socket. A cover member 30 that holds the rubber ring can be attached to the tip side of the socket. The drain pipe fitting is also elbow-shaped, and consists of two fittings 17, 17, each having a socket with the above configuration and an end face 18 on the opposite side, connected by a connecting pipe 19 that connects the end faces.

Description

Technical Field

[0001] The present invention relates to a joint for resin drain pipes.

Background Art

[0002] As a joint for drain pipes that connects resin drain pipes or pipes to each other, vinyl chloride resin (PVC) is used. However, vinyl chloride resin is inferior in heat resistance and chemical resistance. Therefore, when the drain pipe joint is a confluence joint or a cheese joint, cracks may occur due to repeated thermal expansion and contraction caused by the flow of high-temperature drainage. In addition, drain pipes and drain pipe joints made of vinyl chloride resin are not suitable for food factories and kitchens where industrial detergents and high-temperature drainage are used. Therefore, polypropylene resin (PP), which has excellent chemical resistance and heat resistance, is also used for these drainage applications.

[0003] Drain pipes and drain pipe joints made of polypropylene resin cannot be joined with an adhesive, so these joints are performed by EF (electrofusion) joining (see, for example, Patent Document 1). EF joining is a joining method in which a pipe is inserted into a pipe joint in which a heating wire is embedded in the socket, and electricity is supplied from a controller to heat the heating wire, thereby fusing and integrating the pipe and the pipe joint.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] EF joining requires a pipe joint in which a heating wire is embedded in the socket, and also requires a controller for joining, so it is costly in terms of equipment and the construction is relatively troublesome. In addition, once fused, it cannot be removed, so it takes time and cost to replace parts.

[0006] The objective of the present invention is to provide a joint for drainage pipes that has excellent heat resistance and chemical resistance, as well as excellent workability. [Means for solving the problem]

[0007] The drain pipe fitting of the present invention is A drain pipe fitting made of polypropylene resin, Having an opening on at least one side, A rubber ring is fitted onto the inner surface of the aforementioned socket.

[0008] A cover member for holding down the rubber ring can be attached to the tip side of the receiving opening.

[0009] The aforementioned drain pipe fitting is of the elbow type, Two joints, each having a receiving end formed on the opposite side and an end face formed on the opposite side, The end faces are connected by connecting pipes.

[0010] Between the tip of the receiving opening and the cover member, A retaining ring with claws formed on its inner surface can be provided.

[0011] Ribs can be formed along the axial direction on the outer circumference of the socket.

[0012] The joint structure of the present invention is The pipe is connected to the socket of the drain pipe fitting with the above configuration. [Effects of the Invention]

[0013] The drain pipe fitting of the present invention is made of polypropylene resin, and therefore has superior heat resistance and chemical resistance compared to polyvinyl chloride resin. Furthermore, although the drain pipe fitting of the present invention is made of polypropylene resin, a rubber ring is provided inside the socket, allowing for easy joining of drain pipes.

[0014] By adopting a structure connected by a rubber ring, after connecting the drain pipe to the drain pipe joint, the drain pipe joint can be rotated, so it is easy to adjust the gradient. Also, since it is a rubber ring connection, the rubber ring follows the thermal expansion and contraction of the drain pipe and the drain pipe joint and deforms, preventing cracks and the like.

[0015] Furthermore, since the drain pipe joint of the present invention is a rubber ring connection, the drain pipe to be connected is not limited to being made of polypropylene resin, and other pipes with the same outer diameter can be connected.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a cross-sectional view near the receiving port of the drain pipe joint according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the joint structure in which a drain pipe is connected to the drain pipe joint according to the present invention. [Figure 3] FIG. 3 is an enlarged view of the engaging portion between the receiving port and the cover member of the drain pipe joint according to the present invention. [Figure 4] FIG. 4 is a perspective view of a drain pipe joint provided with ribs on the outer periphery. [Figure 5] FIG. 5 is a cross-sectional view of an elbow-shaped drain pipe joint. [Figure 6] FIG. 6 is a cross-sectional view of a drain pipe joint with a retaining ring. [Figure 7] FIG. 7 is a perspective view of the retaining ring. [Figure 8] FIG. 8 is a plan view of the retaining ring. [Figure 9] FIG. 9 is a side view of the retaining ring. [Figure 10] FIG. 10 is a bottom view of the retaining ring. [Figure 11] FIG. 11 is (a) a cross-sectional view taken along line A-A of FIG. 8 and (b) an end view taken along line B-B of FIG. 8. [Figure 12] FIG. 12 is a cross-sectional view of the joint structure in which a drain pipe is connected to a drain pipe joint with a retaining ring. [Figure 13]Figure 13 shows the shape of the claw portion of the retaining ring. [Modes for carrying out the invention]

[0017] The drainage pipe fitting according to the present invention will be described below with reference to the drawings.

[0018] <Drainpipe fitting 10> The drain pipe fitting 10 of the present invention (hereinafter simply referred to as "fitting") is made of polypropylene resin (PP) which has excellent heat resistance and chemical resistance, and as shown in Figure 1, a socket 12 is formed at the tip of a pipe section 11 through which fluid can flow. The socket 12 is larger in diameter than the pipe section 11, a rubber ring 20 is fitted to its inner surface, and a cover member 30 is attached to the tip side. The fitting 10 can be formed, for example, by injection molding.

[0019] The joint 10 can be a socket type or elbow type with sockets 12 at both ends, or it may be a branch joint such as a junction joint or a tee-type joint having three or more sockets 12. The joint 10 may also be in a form where one end is closed.

[0020] As a specific embodiment, the receiving port 12 has a cylindrical portion 13 that is widened at the tip of the pipe portion 11, as shown in Figure 1. A drain pipe 60 (hereinafter simply referred to as "pipe") is inserted into the cylindrical portion 13, as shown in Figure 2. The tip of the cylindrical portion 13 has a further widened rubber ring mounting cylinder 15. A rubber ring 20 is fitted into the rubber ring mounting cylinder 15. The inner diameter of the cylindrical portion 13 can be determined according to the outer diameter of the pipe 60, which will be described later.

[0021] <Rubber ring 20> As shown in Figure 2, the rubber ring 20 is a component that elastically deforms when the pipe 60 is inserted, conforming tightly to the outer surface of the pipe 60 and holding the pipe 60. As a specific embodiment of the rubber ring 20, as shown in Figure 1, an example can be provided in which a lip portion 22 is provided protruding inward from an annular base portion 21 that abuts against the inner surface of the rubber ring mounting cylinder 15. Of course, the configuration of the rubber ring 20 is not limited to this. In the rubber ring 20 of Figure 1, the lip portion 22 protrudes inward beyond the outer diameter of the pipe 60, and when the pipe 60 is inserted into the cylinder portion 13, the lip portion 22 is pushed outward by the outer surface of the pipe 60, thereby holding the pipe 60.

[0022] The rubber ring 20 can be made of synthetic rubber such as styrene-butadiene rubber (SBR), chloroprene rubber (CR), ethylene-propylene diene rubber (EPDM), fluororubber (FKM), or silicone rubber (VMQ). For heat-resistant applications, ethylene-propylene diene rubber, silicone rubber, or fluororubber can be used.

[0023] <Cover member 30> In the embodiment shown in Figure 1, a cover member 30 is attached to the tip of the socket 12 to prevent the rubber ring 20 fitted into the socket 12 from falling off. The cover member 30 has a sleeve 31 that fits around the outer circumference of the socket 12 and an inner flange 33 that protrudes inward from the tip of the sleeve 31. The inner flange 33 has a hole 34 in the center into which the pipe 60 can be inserted. When the sleeve 31 is fitted around the outer circumference of the socket 12, the inner flange 33 closes the outer circumference of the rubber ring mounting cylinder 15 of the socket 12, preventing the rubber ring 20 from falling off.

[0024] The cover member 30 can be attached to the sleeve 31 by engagement, screwing, or adhesive. In Figure 1, the cover member 30 is attached to the receiving opening 12 by engagement. Specifically, as shown in Figure 3, engaging protrusions 14 and 32 are formed on the inner surface of the sleeve 31 and the outer surface of the receiving opening 12, respectively, and the cover member 30 can be attached by pushing the cover member 30 into the receiving opening 12, thereby engaging the engaging protrusions 14 and 32 with each other. The cover member 30 is configured to be attached after the rubber ring 20 is fitted, so that, for example, as in Embodiment 3 described later, if it is desired to insert an additional retaining ring 40, the retaining ring 40 can be inserted before attaching the cover member 30.

[0025] Furthermore, the cover member 30 can be made unnecessary by integrally molding the inner flange 33 inward from the tip of the receiving opening 12. In this case, the rubber ring 20 can be bent to reduce its diameter and pushed into the rubber ring mounting cylinder 15 through the hole 34 in the inner flange 33. Alternatively, the joint 10 may be formed by insert molding.

[0026] <Fabrication of joint 10> As shown in Figure 1, the joint 10 is manufactured by fitting the rubber ring 20 into the rubber ring mounting cylinder 15 of the socket 12, placing the retaining ring 40 on the tip of the socket 12, and attaching the cover member 30.

[0027] <Tube 60> The pipe 60 fitted to the fitting 10 in the above configuration can have various outer and inner diameters depending on the application. The inner diameter of the cylindrical portion 13 of the fitting 10 should be matched to that of the pipe 60.

[0028] The pipe 60 can have an outer diameter of, for example, 40 to 100 mm. The pipe 60 can be made of the same polypropylene resin as the fitting 10, or it may be made of polyvinyl chloride resin or steel pipe. The pipe 60 may also be a single-layer pipe or a multi-layer pipe. In Figure 2, the pipe 60 has a two-layer structure with the inner circumference 61 being polypropylene and the outer circumference 62 being polypropylene mixed with glass fibers, but it may also have a structure of three or more layers.

[0029] <Joint structure 50> To attach the pipe 60 to the fitting 10, simply insert the tip of the pipe 60 into the hole 34 of the inner flange 33 of the fitting 10 and push it in by hand. The pipe 60 enters the cylindrical part 13 while compressing the lip portion 22 of the rubber ring 20. By pushing it in until the tip of the pipe 60 touches the base end of the cylindrical part 13, the pipe 60 is inserted into the cylindrical part 13, and a fitting structure 50 is obtained in which the rubber ring 20 prevents it from coming loose, as shown in Figure 2.

[0030] Since the joint 10 of the present invention is made of polypropylene, it has excellent heat resistance and chemical resistance. Therefore, the joint 10 and joint structure 50 of the present invention are particularly suitable for food factories, kitchens, and the like where industrial detergents and high-temperature wastewater are used.

[0031] Furthermore, since the joint 10 of the present invention is made of polypropylene but uses a rubber ring connection, the joint structure 50 of the present invention allows for easy fine-tuning of the length of the pipe 60 after connecting the pipe 60, and also allows for easy rotation of the pipe 60 relative to the joint 10 to adjust the gradient of the pipe 60 in branch joints. In addition, since the joint structure 50 of the present invention does not involve fusion or bonding of the joint 10 and the pipe 60, parts of the joint 10 and pipe 60 can be easily replaced.

[0032] <Embodiment 1> As shown in Figure 4, the joint 10 has multiple ribs 16 formed on the outer circumference of the cylindrical portion 13. In the illustration, eight ribs 16 are provided at equal intervals parallel to the axial direction of the cylindrical portion 13. If the outer diameter of the cylindrical portion 13 of the joint 10 is smaller than that of the existing piping, it cannot be fitted to existing or commercially available metal pipe support fixtures. However, the ribs 16 allow the outer diameter of the joint 10 to be increased, which has the advantage of allowing the joint 10 to be fixed with existing or commercially available metal pipe support fixtures. In addition, when adjusting the slope by rotating the socket 12 of the joint 10, the ribs 16 serve as a guide for the rotation position, making it easier to adjust the slope.

[0033] <Embodiment 2> The joint 10 in Figure 5 is of the elbow type. The joint 10 is made by cutting a socket-type (straight pipe type) joint, which has receiving openings 12 at both ends, into two pieces (reference numerals 17, 17), and inserting a connecting pipe 19 between the end faces 18, 18 of the two cut joints 17, 17. The socket-type joint is cut at planes 18, 18 perpendicular to the pipe axis, and one or more connecting pipes 19 are cut at different angles depending on the required bending angle, and the end faces are integrated by welding or the like. In the illustration, three connecting pipes 19 are inserted between the cut joints 17, 17, and the connecting pipes 19 are also integrated by welding or the like at their end faces 19c. The cut joints 17, 17 are made of polypropylene, but the connecting pipe 19 is not limited to polypropylene and may be a multilayer pipe with two or more layers. In the illustration, the connecting pipe 19 has a two-layer structure, with the inner circumference 19a being polypropylene and the outer circumference 19b being polypropylene reinforced with glass fibers. The shape of the joint 10 may be cheese-shaped, and the cutting joint 17 may be cut at a plane oblique to the pipe axis and connected to the connecting pipe 19. Furthermore, the cutting joints 17 may be directly joined together.

[0034] <Embodiment 3> As shown in Figure 6, the fitting 10 of this embodiment has a retaining ring 40 in addition to the rubber ring 20. The retaining ring 40 has a number of inwardly facing claws 42. These claws 42 bend to hold the pipe 60 when it is inserted into the fitting 10, and when the inserted pipe 60 moves in the direction of removal, the tips of the claws 42 pierce the outer surface of the pipe 60, preventing the pipe 60 from falling out of the fitting 10.

[0035] The retaining ring 40 is made from a metal plate such as stainless steel with a thickness of 0.2 mm to 1 mm, and has numerous claws 42 protruding inward from the inner circumferential surface of the annular ring portion 41. The tips of the claws 42 are split into two (see Figure 13(a)). As shown in Figure 6, the retaining ring 40 is positioned on the tip side of the rubber ring 20 of the socket 12 of the joint 10. In the illustration, the retaining ring 40 is positioned so that the ring portion 41 is sandwiched between the end face of the socket 12 and the inner flange 33 of the cover member 30.

[0036] As shown in Figure 8, for the retaining ring 40, the outer diameter of the ring portion 41 is φ1, and the inner diameter to the tip of the claw body 42, i.e., the claw 46, is φ2. In this case, φ1 is the diameter that can be inserted into the cover member 30, and φ2 is smaller than the diameter of the pipe 60 so that it can bend when it comes into contact with the pipe 60 to be inserted. φ2 is set to be 1 mm to 10 mm, preferably 3 mm to 6 mm smaller than the outer diameter of the pipe 60. For example, if the outer diameter of the pipe 60 is 89 mm, it is preferable that φ2 be approximately 86 mm. If φ2 is larger than this, the claw body 42 may not come into contact with the pipe 60, or even if it does, it may hardly bend, resulting in weak fixation. On the other hand, if φ2 is smaller than this, it becomes difficult to insert the pipe 60 manually, reducing workability.

[0037] Furthermore, if the proportion of the claws 42 relative to the inner circumference of the retaining ring 40 is small, the pipe 60 is easy to insert, but the fixing strength of the pipe 60 decreases. Conversely, if the proportion of the claws 42 increases, the pipe 60 becomes difficult to insert, reducing workability, while the fixing strength of the pipe 60 improves. The proportion of the claws 42 is determined by the number of claws 42 and the width of each claw 42. To ensure that the pipe 60 is easy to insert and that the fixing strength of the pipe 60 is secured, it is preferable for the proportion of the claws 42 to be 30% to 70%, and more preferably 40% to 60%. In the illustrated embodiment, there are 24 claws 42, and the width of each claw 42 is 6 mm, so the proportion of the claws 42 is approximately 45%.

[0038] Specific embodiments of the retaining ring 40 are shown in Figures 7 to 10, as well as in the cross-sectional view 11(a) along line AA in Figure 8 and the end view 11(b) along line BB in Figure 8. As shown in the figures, the claw body 42 includes a flat portion 44 extending inward from the ring portion 41 in a direction parallel to the ring portion 41, and a claw 46 extending diagonally from the inner end of the flat portion 44. The boundary between the ring portion 41 and the flat portion 44 is called the base portion 43, and the boundary between the flat portion 44 and the claw 46 is called the bent portion 45. As shown in Figure 6, when the claw 46 is attached to the joint 10, it is inclined toward the insertion direction of the pipe 60.

[0039] Of course, the claw body 42 may also be configured such that the flat portion 44 is omitted and the claw 46 extends directly diagonally from the ring portion 41.

[0040] In this embodiment, the claw body 42 does not form the claw 46 directly and obliquely from the ring portion 41, but rather extends a flat portion 44 from the ring portion 41 and forms the claw 46 at the tip of the flat portion 44. This is to make the claw body 42 more flexible by setting the fulcrum for the bending of the claw body 42 far from the tip of the claw 46 when the pipe 60 is inserted into the joint 10. As the outer diameter of the pipe 60 increases, the diameter of the retaining ring 40 also increases, so if the claw body 42 is difficult to bend, it becomes even more difficult to insert the pipe 60 into the joint 10 by hand. Therefore, this embodiment is particularly suitable for application to joints 10 used with large-diameter pipes 60 with a diameter of 48 mm to 114 mm.

[0041] When the claws are formed diagonally directly from the ring portion, the pivot point for the bending of the claws becomes the bend between the ring portion and the claw, and the distance between the tip of the claw and the pivot point becomes shorter, making it difficult for the claws to bend. For this reason, with the same number of claws and claw width, it becomes more difficult to insert the tube 60 compared to the claw body 42 of this embodiment.

[0042] Furthermore, when the claw body 42 is shaped as shown in Figures 7 to 10, it is desirable that the bent portion 45, which is the boundary between the flat portion 44 and the claw 46, be positioned on the inner circumference side of the end face of the rubber ring 20, as shown in Figure 6. This is to prevent interference between the claw 46 and the rubber ring 20 when the claw 46 bends upon contact with the pipe 60.

[0043] Specifically, as shown in Figure 6, when the width of the ring portion 41 of the retaining ring 40, that is, the length from the outer circumference to the base portion 43, is L1, the length of the flat portion 44, that is, the length from the base portion 43 to the bent portion 45, is L2, and the length of the claw 46, that is, the length from the bent portion 45 to the tip, is L3, these dimensions are preferably as follows.

[0044] For example, for large-diameter pipes 60 with an outer diameter of 48 mm to 114 mm, the width L1 of the ring portion 41 is a length that can be sandwiched between the tip of the receiving end 12 and the cover member 30. For example, for large-diameter pipes 60 with an outer diameter of 48 mm to 114 mm, L1 is 3 mm to 7 mm, preferably 4 mm to 6 mm.

[0045] Furthermore, as described above, the length L2 of the flat portion 44 is such that the bent portion 45 is located on the inner circumference side of the end face of the rubber ring 20 in order to avoid interference with the rubber ring 20. As will be explained later, the base portion 43 serves as the fulcrum for the bending of the claw body 42, so it is desirable to make the base portion 43 long. Therefore, for large diameter pipes with an outer diameter of 48 mm to 114 mm, L2 is 1 mm to 8 mm, preferably 1.5 mm to 7.5 mm.

[0046] The length L3 of the claw 46 is the length that reaches the outer circumference of the pipe 60 when the angle θ between the flat portion 44 and the claw 46, as described below, is set so that it protrudes inward from the outer diameter of the pipe 60 by 1 mm to 10 mm, preferably 3 mm to 6 mm. For large diameter pipes with an outer diameter of 48 mm to 114 mm, for example, L3 is 3 mm to 9 mm, preferably 3.5 mm to 8.5 mm.

[0047] The length of the claw body 42 is the sum of the lengths of the flat section 44 and the claw 46 (L2 + L3). If the claw body 42 is long, it will bend more easily, making it easier to insert the pipe 60, but the pipe 60 will also be more likely to come out. Conversely, if the claw body 42 is short, it will bend less, making it difficult to insert the pipe 60, resulting in poor workability. For the above pipe diameter, the length of the claw body 42 (L2 + L3) is preferably 4mm to 17mm, and preferably 5mm to 16mm. The ratio of the lengths of the flat section 44 and the claw 46 is preferably L2:L3 = 30:70 to 70:30, and preferably L2:L3 = 40:60 to 60:40. If one is too long compared to the other, there is a risk of reduced strength.

[0048] Regarding the claw body 42, as shown in Figure 11, when the angle between the flat portion 44 and the claw 46 is θ, it is preferable that θ be between 45° and 65°. If θ is greater than 65°, the angle of the claw 46 with respect to the pipe 60 being inserted is shallow, making it easier to insert the fitting 10, but when the pipe 60 moves in the withdrawal direction, the claw 46 may not penetrate the pipe 60 and may come out. Conversely, if θ is less than 45°, the resistance of the claw 46 when inserting the pipe 60 becomes large, making it time-consuming to insert the pipe 60, or it may not be possible to insert it manually, resulting in poor workability.

[0049] Then, as shown in Figure 6, the retaining ring 40 of the above configuration is placed on the tip of the socket 12 of the joint 10 fitted with the rubber ring 20, and the cover member 30 is engaged to attach it, thereby obtaining the joint 10. As shown in Figure 12, the pipe 60 is connected to the obtained joint 10. When the pipe 60 is inserted through the hole 34 of the cover member 30, the claws 46 of the claw body 42, whose tips protrude inward beyond the outer diameter of the pipe 60, hit the tip of the pipe 60 and bend outward.

[0050] In this embodiment, the claw body 42 has a configuration in which a claw 46 is formed at the tip of the flat portion 44. When the tip of the claw 46 is pushed outward, the claw body 42 flexes with the base 43 shown in Figure 11 as the fulcrum. Because the distance between the tip of the claw 46 and the base 43, which acts as the fulcrum, is relatively long, the resistance of the claw 46 when inserting the pipe 60 can be reduced compared to when the claw is formed directly on the ring portion, and the pipe 60 can be easily inserted even by hand.

[0051] Then, if the pipe 60 is pushed in further, it will enter the cylindrical portion 13 while compressing the lip portion 22 of the rubber ring 20. By pushing the pipe 60 until its tip touches the base end of the cylindrical portion 13, the pipe 60 is inserted into the cylindrical portion 13, and a joint structure 50 is obtained in which the claw body 42 and rubber ring 20 prevent it from coming loose. If a force is applied to the pipe 60 in the pulling direction, the claws 46 of the claw body 42 will pierce the pipe 60, preventing it from coming loose.

[0052] Figure 13 shows examples of the tip shapes of the claws 46 of the claw body 42. Figure 13(a) shows the claw shape used in the retaining ring 40 shown in Figure 7, etc., which is split into two at the tip. Figure 13(b) shows a shape in which the tip of the claw 46 is rectangular. Figure 13(c) shows a shape in which the claw 46 is pointed toward the center. In any of these shapes, the pipe 60 can be fixed stably, but the configuration in Figure 13(c) is easy to insert into the pipe 60 and difficult to remove, followed by Figure 13(a) and then Figure 13(b).

[0053] The above description is for the purpose of explaining the present invention and should not be interpreted as limiting or restricting the scope of the invention described in the claims. Furthermore, it goes without saying that the configuration of each part of the present invention is not limited to the above embodiments and can be modified in various ways within the technical scope described in the claims. [Explanation of Symbols]

[0054] 10 Drain pipe fittings 12 socket 13 Cylinder part 15 Rubber ring mounting tube 16 Ribs 17 Cutting joint 19 Connecting pipe 20 rubber rings 30 Cover component 40 Retaining ring 50 Joint Structure 60 Drain pipe

Claims

1. A drain pipe fitting made of polypropylene resin, Having an opening on at least one side, A rubber ring is fitted onto the inner surface of the aforementioned socket. Drain pipe fittings.

2. A cover member for holding down the rubber ring is attached to the tip side of the receiving opening. A drain pipe fitting according to claim 1.

3. It is elbow-shaped, Two joints, each having a receiving end and an end face on the opposite side, The end faces are connected by connecting pipes, A drain pipe fitting according to claim 2.

4. Between the tip of the receiving opening and the cover member, It is equipped with a retaining ring with claws formed on its inner surface. A drain pipe fitting according to claim 2.

5. Ribs are formed on the outer circumference of the socket along the axial direction. A drain pipe fitting according to claim 2.

6. A pipe is connected to the socket of a drain pipe fitting according to any one of claims 1 to 5. Joint structure.

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