Collective joint, and manufacturing method of collective joint

Abstract

To provide a collective joint capable of improving drainage efficiency.SOLUTION: The collective joint includes: a joint body 16 that is formed tubular in shape, and the axis O is aligned vertically; and a swirling blade 34 placed on the inner peripheral surface of the joint body. The swirling blade has a first blade piece 35 and a second blade piece 36, in which the radially inner ends of each blade are connected to each other. A hollow portion S1 is formed between the first blade piece and the second blade piece.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a mass joint and a method for manufacturing a mass joint. [Background technology]

[0002] Conventionally, buildings such as apartment buildings and office buildings have been equipped with a collective joint system for drainage channels, etc. (See, for example, Patent Document 1.) For example, a collective joint system includes horizontal pipes that collect drainage water on each floor of the building, vertical pipes that direct the collected drainage water downward, and a collective joint that connects the horizontal pipes and the vertical pipes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-038005 Summary of the Invention [Problem to be solved by the invention]

[0004] Swirl vanes are sometimes placed inside the manifold to regulate the flow of wastewater. The manifold of Patent Document 1 has a surface (third inner surface) on the inner circumferential surface of the inclined pipe section of the joint body that faces the swirling direction of the wastewater. The third inner surface is parallel to the axis or gradually inclined toward the side where the swirl vanes incline as it extends downward. When the wastewater flowing inside the inclined pipe section collides with the third inner surface, the flow of wastewater inside the inclined pipe section is disturbed, causing a decrease in drainage efficiency.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a mass joint with improved drainage efficiency, and a method for manufacturing a mass joint. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention proposes the following means. (1) Aspect 1 of the present invention is a collective joint comprising a tubular joint body arranged with its axis aligned in the vertical direction, and a swirl vane provided on the inner peripheral surface of the joint body, the swirl vane having a first vane piece and a second vane piece connected to each other at their respective radially inner ends, and a hollow portion formed between the first vane piece and the second vane piece.

[0007] (2) Aspect 2 of the present invention may be the collective joint described in (1), in which, when the portion of the joint body where the swirl vanes are provided in the up-down direction is defined as the vane arrangement portion, the inner diameter of the vane arrangement portion gradually decreases from top to bottom, and the ratio of the radial length of the swirl vanes to the inner diameter of the vane arrangement portion gradually increases from top to bottom.

[0008] (3) Aspect 3 of the present invention is a method for manufacturing a collective joint that includes a tubular joint body that is arranged so that its axis is aligned in the vertical direction, and swirl vanes that are provided on the inner surface of the joint body, wherein the swirl vanes have first and second vanes that are connected to each other at their respective radially inner ends, and are manufactured by blow molding so that a hollow portion is formed between the first and second vanes. [Effects of the Invention]

[0009] The group joint and the method for manufacturing the group joint of the present invention can improve the efficiency of drainage. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a group joint system including a group joint according to one embodiment of the present invention. [Figure 2] FIG. 2 is a side view of a lower connecting pipe of the same joint assembly. [Figure 3] FIG. 3 is a cross-sectional view taken along the line A1-A1 in FIG. 2. [Figure 4] FIG. 3 is a cross-sectional view taken along the line A2-A2 in FIG. 2. [Figure 5] 1A is a plan view and FIG. 1B is a side view of a parison used in a manufacturing method of a lower connecting pipe of the same assembly joint. [Figure 6] 4 is a cross-sectional view of a mold used in the manufacturing method of the lower connecting pipe. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) Hereinafter, a group joint system in which one embodiment of a group joint according to the present invention is used will be described with reference to FIGS. As shown in Figure 1, this joint assembly system 1 is used for drainage of a building 101. The joint assembly system 1 is arranged on each floor through a slab penetration hole 102a formed in a floor slab 102 of the building 101. Note that Figure 1 shows a simplified configuration of a lower connecting pipe 19, which will be described later.

[0012] The joint collection system 1 includes a joint collection 11, a vertical pipe 46, and a horizontal pipe 48. The joint assembly 11 includes a joint body 16, a third swirl vane (swirl vane) 34, and a horizontal pipe connection portion 41. The joint body 16 is formed in a cylindrical shape and is disposed so that the axis O of the joint body 16 is aligned in the vertical direction. Hereinafter, the circumferential direction X of the joint body 16 (see FIG. 2) will be simply referred to as the circumferential direction X. The radial direction of the joint body 16 will be simply referred to as the radial direction. The joint body 16 includes an upper connecting pipe 17 and a lower connecting pipe 19 connected to the upper connecting pipe 17 via an intermediate pipe 18 . A horizontal pipe connecting portion 41 is fixed to the outer peripheral surface of the upper connecting pipe 17. In this embodiment, a plurality of horizontal pipe connecting portions 41 are provided on the outer peripheral surface of the upper connecting pipe 17. A horizontal pipe 48 is connected to the horizontal pipe connecting portion 41. A damming plate 22 is fixed to the inner peripheral surface of the upper connecting pipe 17. The damming plate 22 prevents wastewater from flowing back into the horizontal pipe 48. The upper connecting pipe 17 is made of vinyl chloride resin or the like.

[0013] A vertical pipe connection part 23 is attached to the upper end of the upper connecting pipe 17. The vertical pipe connection part 23 is equipped with a first swirl vane 24. The first swirl vane 24 is disposed at a position corresponding to the horizontal pipe 48 in the vertical direction. Note that the first swirl vane 24 does not necessarily have to be provided, and instead of the first swirl vane 24, a deflector plate 25 may be provided that protrudes from the inner circumferential surface of the upper connecting pipe 17 toward the axis O, as shown by the dashed line in FIG. 1. The deflector plate 25 is preferably provided upstream of the central axis of the horizontal pipe connecting portion 41, and more preferably upstream of the upper end of the horizontal pipe connecting portion 41. The deflector plate 25 deflects the wastewater flowing in from the vertical pipe 46. The deflector plate 25 is provided for the purposes of preventing collision between the wastewater flowing in from the vertical pipe 46 and the wastewater flowing in from the horizontal pipe connecting portion 41, and preventing the wastewater flowing in from the vertical pipe 46 from flowing back into the horizontal pipe connecting portion 41. For this purpose, the distance from the inner peripheral surface of the upper connecting pipe 17 to the tip 25a of the deflector plate 25 is set to 10 mm or more, and the tip 25a of the deflector plate 25 is sized so as not to protrude beyond the axis O in a cross-sectional view. The distance from the inner surface of the upper connecting pipe 17 to the tip 25a of the deflector plate 25 is preferably more than 15 mm, and the tip 25a of the deflector plate 25 preferably does not protrude more than half the distance from the inner surface of the upper connecting pipe 17 to the axis O in a cross-sectional view.

[0014] On the other hand, if the inner diameter of the upper connecting pipe 17 is smaller than the inner diameter of the vertical pipe 46, the deflector plate 25 provided on the inner peripheral surface of the upper connecting pipe 17 may be 5 mm or less. Moreover, it is preferable that one deflector plate 25 is provided at the same position as the horizontal pipe connecting portion 41 in a top view seen from the axis O, and when there are multiple horizontal pipe connecting portions 41, one deflector plate 25 is provided at the same position as at least one of the horizontal pipe connecting portions 41, and multiple deflector plates 25 may be provided according to the number of horizontal pipe connecting portions 41. Moreover, the deflector plate 25 may be located between multiple horizontal pipe connecting portions 41, or may be provided so as to span multiple horizontal pipe connecting portions 41. A vertical pipe 46 is connected to the vertical pipe connecting portion 23. The outer diameter of the vertical pipe 46 is smaller than the inner diameter of the upper connecting pipe 17.

[0015] The intermediate pipe 18 and the lower connecting pipe 19 are disposed below the horizontal pipe connecting portion 41 . The intermediate tube 18 is preferably made of a polyvinyl chloride resin, and contains a resin composition containing a polyvinyl chloride resin and thermally expandable graphite. That is, the intermediate tube 18 is produced by molding the resin composition. Typically, the intermediate tube 18 is produced by extrusion molding or injection molding the resin composition. Furthermore, the intermediate tube 18 may have a single-layer structure in which the entire intermediate tube 18 is made of a resin composition, or a multi-layer structure made of multiple layers. In the case of a multi-layer structure, it is sufficient that any one of the layers is made of a resin composition. For example, when the intermediate tube 18 has a three-layer structure made of a surface layer, an intermediate layer, and an inner layer, the intermediate layer may be made of a resin composition, and the surface layer, intermediate layer, and inner layer may contain a heat-absorbing agent. In addition, if the intermediate pipe 18 does not contain thermally expandable graphite, a sheet-like fire-resistant material containing thermally expandable graphite may be wrapped around the outer surface of the intermediate pipe 18 or the outer surface of the sound-insulating material covering the intermediate pipe 18, and the fire-resistant material may be embedded in the slab through-hole 102a.

[0016] As an example, a single-layer structure can be used, which is made of a resin composition containing 1 to 20 parts by weight of thermally expandable graphite per 100 parts by weight of polyvinyl chloride resin. Alternatively, a three-layer structure can be used, which is made of a thermally expandable fire-resistant layer made of a resin composition containing 1 to 20 parts by weight of thermally expandable graphite per 100 parts by weight of polyvinyl chloride resin, and coating layers of a polyvinyl chloride resin composition that does not contain thermally expandable graphite that cover the inner and outer surfaces of the thermally expandable fire-resistant layer.

[0017] When the intermediate tube 18 has a single-layer structure, if the amount of thermally expandable graphite is less than 1 part by weight, sufficient thermal expansion may not be obtained during combustion, and the desired fire resistance may not be achieved.If the amount is more than 20 parts by weight, the intermediate tube 18 may expand too much when heated, and may not be able to maintain its shape, causing residue to fall out of the slab through-hole 102a, resulting in a decrease in fire resistance.

[0018] When the intermediate tube 18 has a multi-layer structure, the resin composition containing the thermally expandable fire-resistant material is not particularly limited, but preferably contains 1 to 20 parts by weight of thermally expandable graphite per 100 parts by weight of polyvinyl chloride resin. The content of the thermally expandable graphite is more preferably 4 to 18 parts by weight, and even more preferably 6 to 16 parts by weight. Furthermore, if the intermediate pipe 18 is present throughout the entire slab penetration hole 102a, even if the content of thermally expandable graphite is relatively high at 15 parts by weight or more and the residue is brittle, the residue will block the entire slab penetration hole 102a, and the residue after thermal expansion will be retained within the floor slab 102, making it less likely to fall off.

[0019] When the intermediate layer contains thermally expandable graphite, the intermediate layer is black, so it is preferable that the surface layer and the inner layer contain a colorant other than black so that they can be distinguished from the intermediate layer. The thickness of the surface layer and the inner layer is preferably 0.3 mm to 3.0 mm, and more preferably 0.6 mm to 1.5 mm. If the thickness of the coating layer is 0.3 mm or more, the mechanical strength of the pipe can be sufficiently ensured, and if it is 3.0 mm or less, a decrease in fire resistance can be suppressed. Furthermore, it is preferable that the intermediate tube 18 meets the performance requirements set forth in JIS K6741. That is, if the amount of thermally expandable graphite is less than 1 part by weight, sufficient thermal expansion may not be obtained during combustion, and the desired fire resistance may not be obtained.If the amount of thermally expandable graphite is more than 20 parts by weight, the graphite may expand too much upon heating, and may not be able to maintain its shape, causing residue to fall out of the slab through-holes 102a, resulting in a decrease in fire resistance.

[0020] The thermally expandable graphite used in this embodiment can be, for example, a crystalline compound obtained by acid treating powder of natural scaly graphite, pyrolytic graphite, kish graphite, or the like with an inorganic acid and a strong oxidizing agent to insert the inorganic acid between the layers of the graphite, and then adjusting the pH. As the inorganic acid, concentrated sulfuric acid, nitric acid, selenic acid, etc. can be used. As the strong oxidizing agent, concentrated nitric acid, perchloric acid, perchlorates, permanganates, dichromates, hydrogen peroxide, etc. can be used.

[0021] By adjusting the pH, it is possible to use thermally expandable graphite which is a crystalline compound that maintains the layered structure of carbon and has a pH adjusted to 1.5 to 7.0, and thermally expandable graphite having a 1.3-fold expansion temperature of 180°C to 280°C.

[0022] If the pH of the thermally expandable graphite is less than 1.5, the acidity is too strong and it is likely to cause corrosion of the molding equipment, and if the pH is more than 7.0, the effect of promoting the carbonization of the polyvinyl chloride resin will be weakened, and sufficient fire resistance may not be achieved. The particle size of the thermally expandable graphite is not particularly limited, but for example, the range of 100 to 400 μm, preferably the range of 120 to 350 μm, can be used.

[0023] The resin composition constituting the intermediate tube 18 may contain additives such as stabilizers, inorganic fillers, flame retardants, lubricants, processing aids, impact modifiers, heat resistance improvers, antioxidants, light stabilizers, ultraviolet absorbers, pigments, plasticizers, thermoplastic elastomers, etc., as needed, within the scope that does not impair the object of this embodiment.

[0024] A second swirl vane may be provided on the inner peripheral surface of the intermediate pipe 18. The upper end of the intermediate pipe 18 is fitted inside the lower end of the upper connecting pipe 17. The connecting portion between the upper connecting pipe 17 and the intermediate pipe 18 is joined by, for example, an adhesive or the like. 1, the connection portion between the upper connecting pipe 17 and the intermediate pipe 18 is disposed in a slab penetration hole 102a of a floor slab 102. The slab penetration hole 102a is filled with mortar 103. However, this is not limited to this, and the lower end of the upper connecting pipe 17 and the upper end of the intermediate pipe 18 may be located above the upper surface of the floor slab 102.

[0025] The intermediate tube 18 may be omitted. In this case, the upper connecting pipe 17 and the lower connecting pipe 19 are directly connected. If the connecting pipe portion 31 at the upper end of the lower connecting pipe 19 is a socket, the lower end of the upper connecting pipe 17 is made into a spigot and inserted into the lower connecting pipe 19. If the connecting pipe portion 31 at the upper end of the lower connecting pipe 19 is a spigot, the lower end of the upper connecting pipe 17 is made into a spigot and the lower connecting pipe 19 is inserted into this lower end. Alternatively, an intermediate joint having upper and lower connecting portions to which the connecting pipe portion 31 at the upper end of the lower connecting pipe 19 and the lower end of the upper connecting pipe 17 are respectively connected may be provided between the upper connecting pipe 17 and the lower connecting pipe 19, and the upper connecting pipe 17 and the lower connecting pipe 19 may be connected via this intermediate joint.

[0026] In these cases, the above-mentioned sheet-like fire-resistant material (hereinafter also referred to as fire-resistant sheet) can be provided by wrapping it around the connection portion between the upper connecting pipe 17 and the lower connecting pipe 19. In this case, the fire-resistant sheet is provided on the portion of the upper connecting pipe 17 or the lower connecting pipe 19 that is located below the horizontal pipe connection portion 41. When wrapping a fire-resistant sheet around the lower connecting pipe 19, if the outer surface of the area of ​​the lower connecting pipe 19 where the third swirl vane 34 is present is concave as described below (hollow portion S1 in the inclined pipe section 32, described below; see Figure 2), it is difficult to wrap the fire-resistant sheet around this area. Therefore, it is preferable to wrap the fire-resistant sheet around the area of ​​the lower connecting pipe 19 where the third swirl vane 34 is not present, and specifically, it is preferable to wrap it around the outer surface of the connecting pipe section 31 or the lower pipe section 33. On the other hand, if a filler such as fireproof putty or rock wool is provided in this area, the fireproof sheet will be supported by the filler. Therefore, the fireproof sheet may be wrapped around the lower connecting pipe 19 up to the position where the third swirl vane 34 is located.

[0027] The length of the fireproof material, fireproof sheet, and intermediate pipe 18 in the direction of the axis O (vertical direction) may be, for example, less than 30 mm or 70 mm or more. Furthermore, the collective joint 11 may be combined with a fire-resistant material containing a heat-expandable fire-resistant material installed in a slab penetration hole 102a formed in the floor slab 102 of the building 101, or a fire-resistant material containing a heat-expandable fire-resistant material may be provided on the inner surface, inside or outer surface of a sound-insulating cover provided around the lower connecting pipe 19.If a fire-resistant material is provided on the outside of these collective joints 11, it is not necessary to provide fire-resistant material such as an intermediate pipe 18 or a fire-resistant sheet that is previously provided on the collective joint 11.

[0028] The upper ends of the fire-resistant materials separately provided outside these collective joints 11 may overlap in the direction of the axis O with the lower ends of the fire-resistant materials previously provided in the collective joints 11, or may be at the same position in the direction of the axis O, or may be spaced apart, but it is preferable that the separately provided fire-resistant materials be positioned lower in the up-down direction of the axis O than the fire-resistant materials previously provided in the collective joints 11. Because the upper end of the separately provided fire-resistant material is spaced apart from the lower end of the fire-resistant material previously provided in the collective joint 11, even if the horizontal pipe connection part 41 is installed floating above the upper surface of the floor slab 102, one of the fire-resistant materials can be placed in the slab penetration hole 102a of the floor slab 102. The distance between the lower end of the fire-resistant material previously provided in the collective joint 11 and the upper end of the separately provided fire-resistant material is preferably 30 mm or more, and more preferably more than 70 mm.

[0029] As shown in FIGS. 2 to 4, the lower connecting pipe 19 includes a connecting pipe portion 31, an inclined pipe portion (blade arrangement portion) 32, and a lower pipe portion (vertical pipe connecting portion) 33. In this example, the inclined pipe portion 32 is a portion of the lower connecting pipe 19 (joint body 16) where the third swirl blades 34 are provided in the vertical direction.

[0030] The connecting pipe portion 31 is formed in a cylindrical shape, and as shown in Fig. 1, is fitted onto the outside of the lower end portion of the intermediate pipe 18. The connecting pipe portion 31 is joined to the intermediate pipe 18, for example, by adhesive or the like. 2 to 4, the inclined pipe section 32 is formed in a cylindrical shape and is formed so that its diameter gradually decreases from top to bottom. In other words, the outer diameter and inner diameter of the inclined pipe section 32 are formed so that they gradually decrease from top to bottom. That is, the inner surface of the inclined pipe section 32 is tapered so that it approaches the axis O as it extends downward. 2, the inclined pipe section 32 is disposed coaxially with the connecting pipe section 31. The upper end of the inclined pipe section 32 is fixed to the inner circumferential surface of the lower end of the connecting pipe section 31. In other words, a step is formed between the connecting pipe section 31 and the inclined pipe section 32. The upper end of the inclined pipe portion 32 contacts the lower end of the intermediate pipe 18 from below the intermediate pipe 18 (see FIG. 1).

[0031] 2, the lower pipe portion 33 is formed in a cylindrical shape. The lower pipe portion 33 is arranged coaxially with the inclined pipe portion 32. The upper end portion of the lower pipe portion 33 is fixed to the outer circumferential surface of the lower end portion of the inclined pipe portion 32. In other words, a step is formed between the inclined pipe portion 32 and the lower pipe portion 33. The connecting pipe portion 31 and the lower pipe portion 33 are each a socket. As shown in FIG. 1, a vertical pipe 46 is connected to the lower pipe portion 33. Vertical pipes 46 are connected to the upper and lower ends of the joint body 16. The vertical pipes 46 are arranged coaxially.

[0032] 2 to 4, the third swirl vane 34 is provided on the inner circumferential surface of the inclined pipe section 32 (joint body 16) below the connecting pipe section 31. Alternatively, a portion of the third swirl vane 34 may be fixed to the inner circumferential surface of the inclined pipe section 32, and the remaining portion of the third swirl vane 34 may be fixed to the inner circumferential surface of the connecting pipe section 31 or the lower pipe section 33, or the like. The third swirl vane projects radially inward from the inclined pipe portion 32. The third swirl vane has a first blade piece 35 and a second blade piece .

[0033] The first blade piece 35 and the second blade piece 36 are each formed in a curved plate shape. The first blade piece 35 and the second blade piece 36 gradually extend downward from above toward a first side X1 (hereinafter simply referred to as the first side X1) in the circumferential direction X. Here, the side opposite to the first side X1 in the circumferential direction X is defined as a second side X2 in the circumferential direction X (hereinafter simply referred to as the second side X2). The first blade piece 35 is disposed closer to the first side X1 than the second blade piece 36. The radially inner end of the first blade 35 and the radially inner end of the second blade 36 are connected to each other. Here, "the radially inner end of A" means, for example, "a range from the radially inner end of A to 30% of the radial length of A." The upper end of A is also the same as the radially inner end of A.

[0034] On the other hand, the portion of the first blade 35 other than the end and the portion of the second blade 36 other than the end are spaced apart from each other in the circumferential direction X. A hollow portion (recess) S1 is formed between the portion of the first blade 35 other than the end and the portion of the second blade 36 other than the end. The hollow portion S1 is formed with air and opens radially outward. The upper end of the first blade 35 and the upper end of the second blade 36 are connected to each other, and the lower end of the first blade 35 and the lower end of the second blade 36 are connected to each other.

[0035] Here, the names of each surface are defined as follows: The surface of the first blade 35 facing upward and toward the first side X1 is defined as the first upper surface 35a. The surface of the first blade 35 facing downward and toward the second side X2 is defined as the first lower surface 35b. The surface of the second blade 36 facing upward and toward the first side X1 is defined as the second upper surface 36a. The surface of the second blade 36 facing downward and toward the second side X2 is defined as the second lower surface 36b.

[0036] The hollow portion S1 is formed between the first lower surface 35b and the second upper surface 36a. The first upper surface 35a and the second lower surface 36b are inclined surfaces that gradually extend from top to bottom toward the first side X1. Because the second lower surface 36b is an inclined surface that extends toward the first side X1, like the first upper surface 35a, the wastewater that flows down while being swirled in the direction of the first side X1 by the first swirl vanes 24 and the first vane pieces 35 on the upper floors is not obstructed by the second lower surface 36b, and is drained smoothly, without obstructing the formation of an air core due to the drainage.

[0037] Here, the ratio of the radial length of the third swirl vane 34 to the inner diameter of the inclined pipe section 32 in a given cross section in the axial direction O of the inclined pipe section 32 and the third swirl vane 34 is defined as the swirl vane ratio. The swirl vane ratio gradually increases from top to bottom. The third swirl vane 34 may be configured so that its radial length gradually increases from the top to the bottom. The lower connecting pipe 19 is made of vinyl chloride resin etc. The lower connecting pipe 19 can be manufactured by blow molding (hollow molding).

[0038] It should be noted that there may be no step between the connecting pipe section 31 and the inclined pipe section 32, and between the inclined pipe section 32 and the lower pipe section 33, and they may be connected to each other smoothly.

[0039] A sound-insulating cover may be provided on the outer peripheral surface of the joint body 16 as a sound-insulating measure. The sound-insulating cover is formed, for example, from a sound-insulating sheet having a thickness of 0.8 to 2 mm and made of soft polyvinyl chloride, butyl rubber, or polypropylene (PP) resin or rubber. The sound-insulating cover may be a laminate in which a sound-absorbing layer having a thickness of 5 to 20 mm and made of polyester fiber, urethane foam, glass wool, rock wool, or the like is provided on the inside of the above-mentioned sheet. The sound-insulating cover may also be provided with a fire-resistant material containing a thermally expandable material. The fire-resistant material may be provided on the inner surface of the sound-absorbing layer, inside the sound-absorbing layer, between the sound-absorbing layer and the sound-insulating sheet, or on the outer surface of the sound-insulating sheet. Furthermore, the hollow portion S1 provided on the outer surface of the inclined pipe portion 32 of the lower connecting pipe 19 may be filled with the material that constitutes the sound absorbing layer, thereby eliminating the hollow portion S1 from the outside. This allows the sound insulating cover provided around the lower connecting pipe 19 to be supported by the filled material.

[0040] Next, a method for manufacturing the collective joint 11 configured as above will be described, focusing on a method for manufacturing the lower connecting pipe 19 (hereinafter simply referred to as the manufacturing method). 5, a parison 110, which is a preformed resin, is used for the lower connecting pipe 19. The parison 110 is made of vinyl chloride resin or the like and has a cylindrical shape. For example, parison 110 can be manufactured by extrusion molding. The nominal diameter of parison 110 is preferably 125 to 200, and the outer diameter of parison 110 is more preferably 130 mm or more and 160 mm or less. In this case, a JIS standard pipe can be used as parison 110.

[0041] 6 is used to manufacture the lower connecting pipe 19. The mold 115 includes a first mold 116 and a second mold 121. The first mold 116 has a mold body 117 and a protrusion 118 . The mold body 117 has a rectangular parallelepiped shape. The mold body 117 has a recess 117a formed therein that corresponds to the outer shape of the lower connecting pipe 19 in the circumferential direction X on the side where the third swirl vane 34 is formed. The protrusion 118 protrudes radially inward from the recess 117a of the mold body 117. The protrusion 118 has a shape corresponding to the hollow portion S1 of the lower connecting pipe 19. The second mold 121 has a mold body 122. The mold body 122 is rectangular parallelepiped. A recess 122a is formed in the mold body 122, and the recess 122a corresponds to the outer shape of the lower connecting pipe 19 on the side opposite to the side on which the third swirl vane 34 is formed in the circumferential direction X.

[0042] After the parison 110 is appropriately heated, the molds 116 and 121 are opened (separated from each other), and the parison 110 is placed in the recesses 117a and 122a of the molds 116 and 121. The molds 116 and 121 are closed (brought into contact with each other), and air or the like is injected into the parison 110, causing the parison 110 to deform to fit the shapes of the molds 116 and 121, thereby forming the lower connecting pipe 19 in the mold 115. At this time, the outer and inner diameters of the parison 110 are each deformed smaller (reduced in diameter), forming the lower connecting pipe 19. In this manufacturing method, the third swirl vane 34 has a first vane piece 35 and a second vane piece 36 whose radially inner ends are connected to each other, and the lower connecting pipe 19 is manufactured by blow molding so that a hollow portion S1 is formed between the first vane piece 35 and the second vane piece 36.

[0043] The lower connecting pipe 19 is cooled, the dies 116 and 121 are opened, and the lower connecting pipe 19 is removed from the dies 116 and 121, whereby the lower connecting pipe 19 is manufactured.

[0044] Since the lower connecting pipe 19 is manufactured by blow molding from the parison 110, the inner surface of the lower connecting pipe 19 has a surface roughness similar to that of the inner surface of the parison 110, and fine irregularities are unlikely to form on the inner surface of the lower connecting pipe 19. As described above, in this manufacturing method, the lower connecting pipe 19 (inclined pipe portion 32) and the third swirl vane 34 are formed by blow molding. The upper and lower ends of the lower connecting pipe 19 may be spigots. Since the dimensions of JIS standard pipes are defined by their outer diameters, spigots are suitable for manufacturing the lower connecting pipe 19 by blow molding.

[0045] Next, the operation of the multiple joint system 1 configured as above will be described. The upper vertical pipe 46 and horizontal pipe 48 are connected to a drainage facility (not shown). The wastewater (water) that flows into the collecting joint 11 from the upper vertical pipe 46 and horizontal pipe 48 hits the third swirl blade 34. This wastewater gradually swirls toward the first side X1 as it flows from above to below. This drainage water hits mainly the first upper surface 35a of the first blade piece 35, and also hits the second lower surface 36b of the second blade piece 36. However, the drainage water does not hit the first lower surface 35b of the first blade piece 35 or the second upper surface 36a of the second blade piece 36. The wastewater flows out through the lower vertical pipe 46 to the outside.

[0046] As described above, in the collective joint 11 of this embodiment, the inclined pipe section 32, which is the section where the third swirl vanes 34 are provided, can be manufactured by blow molding. Therefore, even if the inclined pipe section 32 is provided with the third swirl vanes 34, it is difficult for small irregularities to be formed on the inner circumferential surface of the inclined pipe section 32. This reduces the resistance when water flows through the inclined pipe section 32, improving drainage efficiency.

[0047] Furthermore, the inner diameter of the inclined pipe section 32 gradually decreases from top to bottom, and the swirl vane ratio gradually increases from top to bottom. Therefore, when the inclined pipe section 32 and the third swirl vane 34 are manufactured by blow molding, the amount of parison 110 that was not used to form the inclined pipe section 32 increases from top to bottom, and this parison 110 can be used for the third swirl vane 34.

[0048] Furthermore, unlike injection molding, no core mold is required to form the inner surface of the inclined pipe section 32, which not only reduces manufacturing costs but also eliminates the need to consider the removal of the core mold when considering the shape of the lower connecting pipe 19, such as the third swirl vane 34, inclined pipe section 32, connecting pipe section 31, inclined pipe section 32, and lower pipe section 33, meaning there are fewer restrictions on the shape of these lower connecting pipes 19. Specifically, in injection molding, the inclined tube portion 32 below the second vane 36 needs a draft angle to allow the core to be extracted from the lower tube portion 33, but the lower connecting tube 19 of the present invention does not need to have such a draft angle. Also, in injection molding, it is difficult to give the lower tube portion 33 a spigot shape because it makes it difficult to extract the core mold, but in the present invention, there is no need to extract the core mold, so it is easy to make the lower tube portion 33 a spigot.

[0049] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and configuration changes, combinations, deletions, etc. are also included within the scope that does not deviate from the gist of the present invention. For example, in the above-described embodiment, the outer diameter and inner diameter of the inclined pipe portion may be constant regardless of the position in the vertical direction. The position at which the swirl vane is provided on the joint body is not limited. [Explanation of symbols]

[0050] 11. Collective joint 32 Inclined pipe section (blade arrangement section) 34 Third swirl blade (swirl blade) 35 First feather 36 Second feather O axis S1 Hollow part

Claims

1. a joint body formed in a tubular shape and arranged so that its axis is along the vertical direction; Swirl vanes provided on the inner peripheral surface of the joint body; Equipped with the swirl vane has a first vane and a second vane connected to each other at their respective radially inner ends, A hollow portion is formed between the first blade piece and the second blade piece.

2. When the portion of the joint body where the swirl vanes are provided in the up-down direction is defined as a vane arrangement portion, The inner diameter of the blade arrangement portion gradually decreases from top to bottom, The collective joint according to claim 1 , wherein a ratio of the length of the swirl vane in the radial direction to an inner diameter of the vane arrangement portion gradually increases from the top to the bottom.

3. a joint body formed in a tubular shape and arranged so that its axis is along the vertical direction; Swirl vanes provided on the inner peripheral surface of the joint body; A method for manufacturing a mass joint comprising: A method for manufacturing a collective joint, wherein the swirl vane has a first vane piece and a second vane piece connected to each other at their respective radially inner ends, and is manufactured by blow molding so that a hollow portion is formed between the first vane piece and the second vane piece.

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