Elbow and rain gutter system

Abstract

To provide an elbow and a rain gutter system capable of improving drainage capacity.SOLUTION: An elbow 5 is equipped with a bent pipe part 50 and sockets 51, 52 provided at both ends of the bent pipe part 50, respectively. Let ζ be a parameter indicating the difficulty of fluid flow in the curved pipe section 50, and ζ is expressed by the following equation 1. δ is the diameter [mm] of openings 501, 502 of the bent pipe part 50; R is the radius of curvature [mm] of the pipe axis A10 of the bent pipe part 50; ρ is the angle [°] between tangent liness L11, L12 of the pipe axis A10 at the openings 501, 502 in the section in the plane containing the tube axis A10 of the bent pipe part 50. α is the angle [°] between the center lines A11, A12 of the sockets 51, 52 and the tangent lines L11, L12 in the cross-section in the plane containing the pipe axis A. ζ is less than 0.14.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to elbows and gutter systems.

Background Art

[0002] Conventionally, in gutter systems, various elbows (also referred to as elbow joints) have been proposed to allow rainwater to flow smoothly (see Patent Documents 1 and 2).

[0003] The elbow disclosed in Patent Document 1 is an elbow installed on the downstream side of a siphon generating portion, and includes a curved pipe portion and receiving ports provided at both ends of the curved pipe portion. The radius of curvature of the inner wall surface on the inner peripheral side in the curved pipe portion is greater than 0 mm and less than 64 mm.

[0004] The elbow disclosed in Patent Document 2 is an elbow installed on the downstream side of a siphon gutter system including an eaves gutter and a cylindrical portion penetrating a water collecting port formed on the bottom surface of the eaves gutter, and a siphon generating portion for generating a siphon phenomenon. The elbow includes a curved pipe portion and receiving ports provided at both ends of the curved pipe portion. When viewed in a cross section in a plane including the pipe axis of the curved pipe portion, the radius of curvature of the inner wall surface on the inner peripheral side in the curved pipe portion is greater than 64 mm and less than 125 mm.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years in Japan, the amount of rainfall per unit time has tended to increase due to heavy rainstorms and the like, and there is a demand for a gutter system with improved drainage capacity.

[0007] The present disclosure provides an elbow and a rain gutter system that enable an improvement in drainage capacity.

Means for Solving the Problem

[0008] The elbow according to one aspect of the present disclosure includes a curved pipe portion having openings at both ends, and receiving ports provided at both ends of the curved pipe portion, respectively. When a parameter indicating the flow resistance of the fluid in the curved pipe portion is ζ, ζ is represented by the following formula.

Equation

[0009] The elbow according to another aspect of the present disclosure includes a curved pipe portion having openings at both ends, and receiving ports provided at both ends of the curved pipe portion, respectively. In the cross section in the plane including the pipe axis of the curved pipe portion, the first intersection of the center line of the receiving port is on the side opposite to the pipe axis with respect to the first inner wall surface of the outer peripheral portion of the curved pipe portion. In the cross section in the plane including the pipe axis, the second intersection of the tangent of the pipe axis at the opening of the curved pipe portion is closer to the first inner wall surface than the pipe axis. The radius of curvature of the second inner wall surface of the inner peripheral portion of the curved pipe portion in the cross section in the plane including the pipe axis is 130 mm or more.

[0010] The rain gutter system according to one aspect of the present disclosure includes a vertical gutter fixed to the wall surface of a building, a downspout for flowing rainwater from the building to the vertical gutter from a drop opening, a first elbow connecting the upstream end of the downspout to the drop opening, and a second elbow connecting the downstream end of the downspout to the upstream end of the vertical gutter. At least one of the first elbow and the second elbow is an elbow according to any of the above aspects.

Advantages of the Invention

[0011] Aspects of the present disclosure enable an improvement in drainage capacity.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, a more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and duplicate descriptions of substantially the same configurations may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art. Note that the inventors provide the accompanying drawings and the following description so that those skilled in the art can fully understand the present disclosure, and do not intend to limit the subject matter described in the claims thereby.

[0014] The positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Each of the drawings described in the following embodiments is a schematic diagram, and the ratios of the sizes and thicknesses of the respective components in each drawing do not necessarily reflect the actual dimensional ratios. Also, the dimensional ratios of the respective elements are not limited to the ratios illustrated in the drawings.

[0015] [1. Embodiment] [1.1 Configuration] FIG. 1 is a schematic diagram of a configuration example of the rain gutter system 1 according to the present embodiment. The rain gutter system 1 in FIG. 1 receives rainwater from the roof 11 of the building 10 and flows it to the step portion 21 on the ground 20. The rainwater collected in the step portion 21 flows out from the step portion 21 through the buried pipe 22 into the rainwater pipe. The building 10 is, for example, a building of a non-residential facility such as a store, an office, a factory, a building, a school, a welfare facility, or a hospital, and a residential facility such as a detached house, an apartment house, or each dwelling unit of a detached house or an apartment house. The non-residential facilities also include a theater, a cinema, a concert hall, a game arcade, a complex facility, a department store, a hotel, an inn, a kindergarten, a library, a museum, an art museum, an underground shopping street, a station, and an airport, etc.

[0016] The rain gutter system 1 in FIG. 1 includes a eaves gutter 2, a downspout 3, a leader 4, and first and second elbows 5A, 5B.

[0017] The eaves gutter 2 receives rainwater from the roof 11 of the building 10. The eaves gutter 2 is installed under the roof 11 of the building 10. The eaves gutter 2 has a long barrel shape. The eaves gutter 2 in FIG. 1 has a bottom wall 2a, and there is a drain hole 2b in the bottom wall 2a. In FIG. 1, a drain 6 is arranged at the drain hole 2b of the eaves gutter 2. The drain 6 reduces the generation of vortices and the entrainment of air at the drain hole 2b.

[0018] In the rain gutter system 1 in FIG. 1, the downspout 3, the leader 4, and the first and second elbows 5A, 5B form a flow path for flowing the rainwater from the drain hole 2b to the step portion 21 on the ground 20.

[0019] The vertical downspout 3 is a part that vertically drains rainwater from the drain opening 2b. The vertical downspout 3 is in a straight tubular shape. The cross-section perpendicular to the pipe axis of the vertical downspout 3 is circular. The material of the vertical downspout 3 is rigid polyvinyl chloride. The dimensions of the vertical downspout 3, such as the outer shape and thickness, may be set in accordance with the standards of the rigid polyvinyl chloride pipe (general) in JIS K 6741, "Rigid Polyvinyl Chloride Pipe". The vertical downspout 3 in FIG. 1 is fixed to the wall surface 12 of the building 10 so that the direction of the pipe axis of the vertical downspout 3 coincides with the vertical direction. The vertical downspout 3 has an upstream end 3a and a downstream end 3b. The upstream end 3a is the end (the upper end in FIG. 1) of the vertical downspout 3 that is connected to the drain opening 2b. The downstream end 3b is the end (the lower end in FIG. 1) of the vertical downspout 3 that is inserted into the step part 21. In FIG. 1, the drain pipe cover 7 is arranged so that rainwater does not flow into the step part 21 from the gap between the vertical downspout 3 and the step part 21. In FIG. 1, the vertical downspout 3 is fixed to the wall surface 12 of the building 10 by the holding fittings 30a, 30b, and 30c. In FIG. 1, H1 is the distance [mm] from the ground 20 to the upper end of the vertical downspout 3. H11 is the distance [mm] from the upper end of the vertical downspout 3 to the uppermost holding fitting 30a. H12 is the distance [mm] from the ground 20 to the lowermost holding fitting 30c. H13 is the pitch [mm] between the holding fittings 30a, 30b, and 30c. Generally, H11 and H12 are 200 mm or more and 300 mm or less. H13 is 800 mm or more and 1200 mm or less, and in a fixed case, it is 1000 mm or less. D1 is the distance between the vertical downspout 3 and the wall surface 12. Generally, D1 is 30 mm or more and 100 mm or less.

[0020] The downspout 4 is a part for flowing rainwater from the building 10 from the drain opening 2b to the vertical pipe 3. The downspout 4 is between the drain opening 2b of the rainwater from the building 10 and the vertical pipe 3. The downspout 4 is straight tubular. The cross-section orthogonal to the pipe axis of the downspout 4 is circular. The material of the downspout 4 is rigid polyvinyl chloride. The downspout 4 in Fig. 1 is fixed such that the direction of the pipe axis of the downspout 4 is inclined with respect to the vertical direction. The downspout 4 has an upstream end 4a and a downstream end 4b. The upstream end 4a is the end (the upper end in Fig. 1) connected to the drain opening 2b in the downspout 4. The downstream end 4b is the end (the lower end in Fig. 1) connected to the vertical pipe 3 in the downspout 4. The downspout 4 is cylindrical. The material of the downspout 4 is rigid polyvinyl chloride. The dimensions of the downspout 4, for example, the outer shape and the thickness, may be set in accordance with the standard of the rigid polyvinyl chloride pipe (general) of JIS K 6741 "Rigid Polyvinyl Chloride Pipe". In Fig. 1, D2 is the eccentricity distance [mm]. The eccentricity distance is the distance between the center line of the drain opening 2b and the center line of the vertical pipe 3. D2 may be set to 1000 mm or less, for example.

[0021] The first elbow 5A connects the upstream end 4a of the downspout 4 to the drain opening 2b. The second elbow 5B connects the downstream end 4b of the downspout 4 to the upstream end 3a of the vertical pipe 3. In the present embodiment, the first elbow 5A and the second elbow 5B have the same shape. Hereinafter, for the sake of easy understanding of the explanation, when the first elbow 5A and the second elbow 5B are not distinguished, they are simply referred to as an elbow and denoted by the reference numeral 5.

[0022] Fig. 2 is a cross-sectional view of a configuration example of the elbow 5. The elbow 5 has a curved pipe portion 50 and receiving ports 51, 52. The curved pipe portion 50 and the receiving ports 51, 52 are formed continuously and integrally. The material of the elbow 5, that is, the material of the curved pipe portion 50, is rigid polyvinyl chloride.

[0023] The bent pipe portion 50 has openings 501 and 502 at both ends. The bent pipe portion 50 is cylindrical, but the pipe axis (center line) A10 of the bent pipe portion 50 is not linear but curved. That is, the bent pipe portion 50 has a curved pipe axis A10. FIG. 2 is a cross-sectional view of the elbow 5 in a plane including the pipe axis A10 of the bent pipe portion 50. The inner diameter of the bent pipe portion 50 of the elbow 5 in FIG. 2 is uniform. Therefore, in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50, the center of the circle defining the radius of curvature of the pipe axis A10, the center of the circle defining the radius of curvature of the inner wall surface 50b of the inner peripheral portion 50a of the pipe axis A10, and the center of the circle defining the radius of curvature of the inner wall surface 50d of the outer peripheral portion 50c of the pipe axis A10 coincide. Hereinafter, the inner wall surface 50d may be referred to as the first inner wall surface 50d, and the inner wall surface 50b may be referred to as the second inner wall surface 50b.

[0024] The receiving ports 51 and 52 are respectively provided at both ends of the bent pipe portion 50. The receiving port 51 is cylindrical and surrounds the opening 501 of the bent pipe portion 50. The receiving port 52 is cylindrical and surrounds the opening 502 of the bent pipe portion 50. The center lines A11 and A12 of the receivers 51 and 52 pass through the centers C1 and C2 of the openings 501 and 502. The center lines A11 and A12 of the receivers 51 and 52 are not curved but linear. In FIG. 2, the receiving ports 51 and 52 have the same shape. FIG. 2 shows D, d, and l as the dimensions of the receiving port 51 of the elbow 5. l is the length of the receiving port 51 (or the length of the receiving port 52) in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50. D is the outer diameter [mm] of the receiving port 51 (or the receiving port 52). d is the inner diameter [mm] of the receiving port 51 (or the receiving port 52). The dimensions D, d, and l of the elbow 5 may be set in accordance with, for example, the standards of JIS K 6739 "Rigid Polyvinyl Chloride Pipe Fittings for Drainage".

[0025] In the elbow 5, as shown in Fig. 2, in the cross-section in the plane including the pipe axis A10 of the curved pipe portion 50, the tangent line L11 of the pipe axis A10 at the opening 501 of the curved pipe portion 50 is inclined with respect to the center line A11 of the receiving port 51. Since the pipe axis A10 passes through the center C1 of the opening 501, the tangent line L11 passes through the center C1 of the opening 501. In the cross-section in the plane including the pipe axis A10 of the curved pipe portion 50, the tangent line L12 of the pipe axis A10 at the opening 502 of the curved pipe portion 50 is inclined with respect to the center line A12 of the receiving port 52. Since the pipe axis A10 passes through the center C2 of the opening 502, the tangent line L12 passes through the center C2 of the opening 502. Thus, since the tangent lines L11 and L12 are inclined with respect to the center lines A11 and A12 respectively, the intersection point P1 of the center lines A11 and A12 of the receiving ports 51 and 52 does not coincide with the intersection point P2 of the tangent lines L11 and L12 of the pipe axis A10 at the openings 501 and 502 of the curved pipe portion 50. Hereinafter, the intersection point P1 may be referred to as the first intersection point P1, and the intersection point P2 may be referred to as the second intersection point P2.

[0026] The inventors have found that the flow resistance of the fluid in the curved pipe portion 50 of the elbow 5 in Fig. 2 can be evaluated based on the loss coefficient of the bend pipe and the loss coefficient of the elbow pipe. The loss coefficient of the bend pipe and the loss coefficient of the elbow pipe can be calculated based on the experimental formula of Weissbach. Let the parameter indicating the flow resistance of the fluid in the curved pipe portion 50 be ζ, then ζ is represented by the following formula (1).

[0027]

Equation

[0028] As is clear from the above equation (1), ζ is a function of δ, R, ρ, and α. δ is the diameter [mm] of the openings 501 and 502 of the bent pipe portion 50. R is the radius of curvature [mm] of the pipe axis A10 of the bent pipe portion 50. ρ is the angle (bend angle) [°] between the tangents L11 and L12 at the openings 501 and 502 of the pipe axis A10 in the cross-section in the plane including the pipe axis A of the bent pipe portion 50. α is the angle (refraction angle) [°] between the center line A11 of the inlet 51 and the tangent L11 when viewed in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50. α is also the angle [°] between the center line A12 of the inlet 52 and the tangent L12 when viewed in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50.

[0029] When the angle [°] between the center lines A11 and A12 of the inlets 51 and 52 when viewed in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50 is θ, geometrically, the following relationship of equation (2) holds for ρ. However, ρ > θ. α is positive.

[0030]

Equation

[0031] As is clear from the above equation (2), ρ is a function of θ and α.

[0032] For α, geometrically, the following relationship of equation (3) holds. More specifically, in FIG. 2, in the triangle with the center O of the circle defining the radius of curvature R, the intersection point P1, and the center C1 as vertices, if the length of the side between the center O and the intersection point P1 is E, then from the cosine theorem, E 2 = R 2 + Z 2 - 2×RZ cos(α + 90), and, R 2 = E 2 + Z 2 - 2×EZ cos(θ / 2) holds. By eliminating E from these equations and arranging them, the following equation (3) is obtained.

[0033]

Equation

[0034] As is apparent from the above formula (3), α is a function of θ, R, and Z. As shown in FIG. 2, Z is the distance between the opening 501 or 502 of the bent pipe portion 50 and the intersection point P1 of the center lines A11 and A12 of the inlets 51 and 52 when viewed in a cross section in a plane including the pipe axis A10 of the bent pipe portion 50.

[0035] From the above formulas (1) to (3), it can be seen that ζ is determined by δ, θ, R, and Z.

[0036] In the elbow 5 of FIG. 2, in a cross section in a plane including the pipe axis A10 of the bent pipe portion 50, the circle defining the radius of curvature R of the pipe axis A10 and the circle defining the radius of curvature r of the inner wall surface 50b of the inner peripheral portion 50a of the pipe axis A10 have the same center O. For R, r, and δ, the following formula (4) holds.

[0037]

Number

[0038] Z is set within a range where α is positive. In this case, since it is only necessary for the denominator on the right side of the above formula (3) to be negative, Z satisfies the following formula (5).

[0039]

Number

[0040] As described above, δ is the diameter [mm] of the openings 501 and 502 of the bent pipe portion 50. δ may be determined in consideration of the target drainage capacity of the rain gutter system 1 or the like. δ may be set in accordance with the standards of JIS K 6739 "Rigid Polyvinyl Chloride Pipe Fittings for Drainage". δ may be set, for example, so as to satisfy the reference dimensions of the nominal diameters defined in JIS K 6739. According to JIS K 6739 "Rigid Polyvinyl Chloride Pipe Fittings for Drainage", when the nominal diameters are 75 mm, 100 mm, and 125 mm, the reference dimensions are 77.2 mm, 98.8 mm, and 125 mm, respectively.

[0041] As described above, θ is the angle [°] between the centerlines A11 and A12 of the inlets 51 and 52 when viewed in a cross-section in the plane including the pipe axis A10 of the curved pipe portion 50. In the standard of the VU large bend elbow joint of JIS K 6714 "Rigid Polyvinyl Chloride Pipe", θ is set to 91.17°. In the rain gutter system 1, in order to efficiently flow rainwater from the drain port 2b to the collecting portion 21, the upstream end 4a of the downspout 4 should be higher than the downstream end 4b of the downspout 4. However, in the vertical gutter 3, expansion and contraction due to temperature difference may occur. When the vertical gutter 3 thermally expands, the downstream end 4b of the downspout 4 can be lifted by the vertical gutter 3. In this case, the downspout 4 can be in an inverted gradient state where the downstream end 4b of the downspout 4 is higher than the upstream end 4a of the downspout 4. In the inverted gradient state, it becomes difficult for rainwater to flow in the downspout 4, so the flow of rainwater from the drain port 2b to the collecting portion 21 can be hindered. Therefore, θ is preferably set so that the downspout 4 is less likely to be in an inverted gradient state.

[0042] Figure 3 is a schematic explanatory diagram of the dimensions of the rain gutter system 1. In the rain gutter system 1, the first and second elbows 5A and 5B are small with respect to the vertical gutter 3 and the downspout 4. In Figure 3, the vertical gutter 3 and the downspout 4 are shown schematically as lines, and the first and second elbows 5A and 5B and the retaining fitting 30a are shown schematically as dots. In Figure 3, the solid line indicates the state during construction, and the dotted line indicates the state after thermal expansion. In Figure 3, h is the length [mm] serving as the reference for the thermal expansion of the vertical gutter 3. h is, for example, the pitch of the members for absorbing the expansion and contraction of the vertical gutter 3. When a member for absorbing the expansion and contraction of the vertical gutter 3 is installed at one place every 8000 mm, h is 8000 mm. Δh is the amount of elongation [mm] of the vertical gutter 3 due to thermal expansion. Δh is given by h×c×(t2 - t1). c is the linear expansion coefficient [1 / °C] of the material of the vertical gutter 3. t1 is the maximum surface temperature [°C] of the vertical gutter 3. t2 is the temperature [°C] at the time of construction of the rain gutter system 1.

[0043] β1 is the angle [°] of the downspout 4 with respect to the horizontal plane during the construction of the rain gutter system 1. β1 is given by θ - 90. β2 is the angle [°] of the downspout 4 with respect to the horizontal plane during the thermal expansion of the vertical gutter 3 of the rain gutter system 1. β2 is given by β1 - tan -1 (Δh / D2). Therefore, β2 can be expressed by the following equation (5).

[0044]

Equation

[0045] θ is set, for example, such that β2 is substantially 0 or more. In this way, the possibility of the downspout 4 being in an inverted gradient state is reduced, and the rain gutter system 1 can exhibit stable drainage capacity.

[0046] When θ is changed with h, D2, c, t1, and t2 as fixed values, the relationship between θ and β2 is as shown in Table 1 below. Here, h is 8000 mm. D2 is 356 mm, which is the minimum value of a general eccentric distance. c is 8×10 -5 / °C, which is the upper limit value of the range of the linear expansion coefficient of general rigid polyvinyl chloride. t1 is 60°C, assuming midsummer. t2 is -10°C, assuming midwinter. In this case, Δh becomes 44.8 mm.

[0047]

Table 1

[0048] From the results in Table 1, when θ is near 90°, when the vertical downspout 3 extends upward due to thermal expansion and contraction, the leader pipe 4 is likely to be in an inverted gradient state. When the leader pipe 4 is in an inverted gradient state, the occurrence of the siphon phenomenon in the gutter system 1 is inhibited, and the drainage capacity may decrease. Considering such points, θ is preferably 97° or more. In particular, θ is preferably 97.17° or more. In particular, θ is preferably 98° or more. Considering the variations during product and construction, θ is preferably 100° or more. In particular, θ is preferably 103° or more. Furthermore, θ is preferably 105° or more.

[0049] On the other hand, as θ increases, the distance between the uppermost retaining fitting 30a of the vertical downspout 3 and the drain 6 in the vertical direction tends to increase. In the gutter system 1, between the uppermost retaining fitting 30a of the vertical downspout 3 and the drain 6, there are the leader pipe 4 and the first and second elbows 5A, 5B. The leader pipe 4 and the first and second elbows 5A, 5B are not necessarily fixed to the building 10. Therefore, when the distance between the uppermost retaining fitting 30a of the vertical downspout 3 and the drain 6 in the vertical direction increases, the leader pipe 4 and the first and second elbows 5A, 5B become unstable, and the structural stability of the gutter system 1 may decrease. Thus, so that the structural stability of the gutter system 1 does not decrease, θ is preferably set such that, for example, the distance between the uppermost retaining fitting 30a of the vertical downspout 3 and the drain 6 in the vertical direction is equal to or less than the upper limit value of the pitch between the retaining fittings 30a, 30b, 30c of the vertical downspout 3.

[0050] In FIG. 3, H2 corresponds to the distance between the uppermost retaining fitting 30a of the vertical downspout 3 and the drain 6 in the vertical direction. H2 is the sum of H11, which is the distance [mm] from the upper end of the vertical downspout 3 to the uppermost retaining fitting 30a, and H3. H3 indicates the amount of descent due to the leader pipe 4. H3 is represented by D2×tan(θ - 90). Therefore, H2 can be expressed by the following formula (5).

[0051]

Equation

[0052] θ is set such that, for example, H2 is equal to or less than the upper limit value of the recommended pitch of the elbows of the vertical downspout 3. The recommended pitch of the elbows of the vertical downspout 3 is, for example, 800 mm or more and 1200 mm or less. The upper limit value of the recommended pitch is 1200 mm. By setting θ such that H2 is 1200 mm or less, the structural stability of the rain gutter system 1 can be improved.

[0053] When θ is changed with H11 and D2 as fixed values, the relationship between θ and H2 is as shown in Table 2 below. Here, H11 is 200 mm. In this case, H3 (= D2 × tan(θ - 90)) is 1000 mm. D2 is 1000 mm, which is the maximum value of a general eccentricity distance.

[0054]

Table 2

[0055] From the results in Table 2, θ is preferably 135° or less. In particular, θ is preferably 128° or less such that H2 is equal to or less than the lower limit value (800 mm) of the recommended pitch of the elbows of the vertical downspout 3. In particular, θ is preferably 120° or less such that H3 is equal to or less than the lower limit value (800 mm) of the recommended pitch of the elbows of the vertical downspout 3. Furthermore, θ is preferably 105° or less.

[0056] Next, when R and Z were changed, the flow resistance of the fluid in the bent pipe portion 50 was evaluated by the parameter ζ indicating the flow resistance of the fluid in the bent pipe portion 50 of the elbow 5. In the evaluation, considering using rigid polyvinyl chloride pipes with nominal diameters of 75 mm, 100 mm, and 125 mm specified in JIS K 6741 as the vertical pipe 3 and the downspout 4, δ was set so as to correspond to nominal diameters of 75 mm, 100 mm, and 125 mm respectively. Table 3 shows a part of the evaluation results for the case of a nominal diameter of 75 mm, and δ is 77.2 mm. Table 4 shows a part of the evaluation results for the case of a nominal diameter of 100 mm, and δ is 98.8 mm. Table 5 shows a part of the evaluation results for the case of a nominal diameter of 125 mm, and δ is 125 mm. In any of the evaluations in Tables 3, 4, and 5, θ was set to 105°. In order to make the fluid flow in the bent pipe portion 50 of the elbow 5 smooth, the radius of curvature r of the inner wall surface 50b of the inner peripheral portion 50a of the pipe axis A10 is preferably 130 [mm] or more. From the above formula (4), in the case of a nominal diameter of 75 mm, the radius of curvature R of the pipe axis is preferably 180 mm or more. In the case of a nominal diameter of 100 mm, the radius of curvature R of the pipe axis is preferably 180 mm or more. In the case of a nominal diameter of 125 mm, the radius of curvature R of the pipe axis is preferably 200 mm or more.

[0057]

Table 3

[0058]

Table 4

[0059]

Table 5

[0060] As criteria for evaluating ζ, ζ was calculated for a normal elbow commercially available as a 90° large bend elbow (abbreviation LL) in JIS K 6739 "Rigid Polyvinyl Chloride Pipe Fittings for Drainage" and an elbow commercially available for high drainage applications. The ζ of the normal elbow was approximately 0.14 for a nominal diameter of 75 mm, approximately 0.14 for a nominal diameter of 100 mm, and approximately 0.15 for a nominal diameter of 125 mm. The ζ of the elbow commercially available for high drainage applications was approximately 0.12 for a nominal diameter of 75 mm, approximately 0.12 for a nominal diameter of 100 mm, and approximately 0.13 for a nominal diameter of 125 mm. Therefore, it is preferable that the ζ of elbow 5 is less than 0.14, and more preferably less than 0.12. In Tables 3, 4, and 5, "〇" indicates that the ζ of elbow 5 is less than 0.12. "◎" indicates that the ζ of elbow 5 is less than 0.12 and is less than or equal to 1.1 times the minimum value of ζ with respect to Z. Note that in Tables 3, 4, and 5, "×" means that Z does not satisfy formula (5).

[0061] Next, with reference to FIGS. 2, 4, and 5, the change in the shape of elbow 5 when R and Z are changed will be described. FIG. 4 is a cross-sectional view of another configuration example of elbow 5. FIG. 5 is a cross-sectional view of another configuration example of elbow 5. In elbow 5 of FIGS. 2, 4, and 5, δ is 98.8 [mm] and θ is 105 [°].

[0062] In the elbow 5 of FIG. 2, R is 180 [mm] and Z is 90 [mm]. In the cross-section of the elbow 5 of FIG. 2 in the plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 of the center lines A11, A12 of the inlets 51, 52 and the second intersection point P2 of the tangents L11, L12 of the pipe axis A10 at the openings 501, 502 of the curved pipe portion 50 are on a straight line passing through the center O of the circle defining the radius of curvature R of the pipe axis A10. In the cross-section of the plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 is between the intermediate line M1 between the pipe axis A10 of the curved pipe portion 50 and the first inner wall surface 50d of the outer peripheral portion 50c of the curved pipe portion 50 and the first inner wall surface 50d. In the cross-section of the plane including the pipe axis A10, the second intersection point P2 is between the intermediate line M1 and the pipe axis A10.

[0063] In the elbow 5 of Fig. 4, R is 260 [mm] and Z is 150 [mm]. In the elbow 5 of Fig. 4, in the cross-section in the plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 of the center lines A11 and A12 of the inlets 51 and 52 and the second intersection point P2 of the tangents L11 and L12 of the pipe axis A10 at the openings 501 and 502 of the curved pipe portion 50 are on a straight line passing through the center O of the circle defining the radius of curvature R of the pipe axis A10. In the cross-section in the plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 is on the side opposite to the pipe axis A10 of the curved pipe portion 50 with respect to the first inner wall surface 50d of the outer peripheral portion 50c of the curved pipe portion 50. The first intersection point P1 is outside the curved pipe portion 50. In the cross-section in the plane including the pipe axis A10, the second intersection point P2 is closer to the first inner wall surface 50d than the pipe axis A10. In Fig. 4, the second intersection point P2 is between the intermediate line M1 and the first inner wall surface 50d.

[0064] In the elbow 5 of Fig. 5, R is 340 [mm] and Z is 230 [mm]. In the elbow 5 of Fig. 5, in the cross-section in the plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 of the center lines A11 and A12 of the inlets 51 and 52 and the second intersection point P2 of the tangents L11 and L12 of the pipe axis A10 at the openings 501 and 502 of the curved pipe portion 50 are on a straight line passing through the center O of the circle defining the radius of curvature R of the pipe axis A10. In the cross-section in the plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 is on the side opposite to the pipe axis A10 of the curved pipe portion 50 with respect to the first inner wall surface 50d of the outer peripheral portion 50c of the curved pipe portion 50. In the cross-section in the plane including the pipe axis A10, the second intersection point P2 is between the first inner wall surface 50d and the first intersection point P1. As shown in Fig. 5, the first intersection point P1 and the second intersection point P2 are outside the curved pipe portion 50.

[0065] Thus, in a cross-section in a plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 may be on the side opposite to the pipe axis A10 of the curved pipe portion 50 with respect to the first inner wall surface 50d of the outer peripheral portion 50c of the curved pipe portion 50. The first intersection point P1 may be outside the curved pipe portion 50. In a cross-section in a plane including the pipe axis A10, the second intersection point P2 may be closer to the first inner wall surface 50d than the pipe axis A10. The second intersection point P2 may be between the first inner wall surface 50d and the first intersection point P1 on the side opposite to the pipe axis A10 of the curved pipe portion 50 with respect to the first inner wall surface 50d of the outer peripheral portion 50c of the curved pipe portion 50. The second intersection point P2 may be outside the curved pipe portion 50.

[0066] When comparing ζ in the elbows 5 of FIGS. 2, 4, and 5, ζ of the elbow 5 in FIG. 4 is the smallest, and the fluid flows easily in the curved pipe portion 50. When comparing the elbows 5 of FIGS. 2, 4, and 5, in a cross-section in a plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 is preferably on the side opposite to the pipe axis A10 of the curved pipe portion 50 with respect to the first inner wall surface 50d of the outer peripheral portion 50c of the curved pipe portion 50. In particular, the first intersection point P1 is preferably outside the curved pipe portion 50. In a cross-section in a plane including the pipe axis A10, the second intersection point P2 is preferably closer to the first inner wall surface 50d than the pipe axis A10. In particular, the second intersection point P2 is preferably between the first inner wall surface 50d and the first intersection point P1 on the side opposite to the pipe axis A10 of the curved pipe portion 50 with respect to the first inner wall surface 50d of the outer peripheral portion 50c of the curved pipe portion 50.

[0067] [1.2 Effects, etc.] The elbow 5 described above includes a curved pipe portion 50 having openings 501 and 502 at both ends, and receiving ports 51 and 52 provided at both ends of the curved pipe portion 50, respectively. When a parameter indicating the difficulty of fluid flow in the curved pipe portion 50 is ζ, ζ is represented by the following equation. [Equation] δ is the diameter [mm] of the openings 501 and 502 of the bent pipe portion 50. R is the radius of curvature [mm] of the pipe axis A10 of the bent pipe portion 50. ρ is the angle [°] between the tangents L11 and L12 of the pipe axis A10 at the openings 501 and 502 of the bent pipe portion 50 in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50. α is the angle [°] between the center lines A11 and A12 of the inlets 51 and 52 and the tangents L11 and L12 in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50. ζ is less than 0.14. This configuration enables an improvement in drainage capacity.

[0068] In the elbow 5, ζ is less than 0.12. This configuration enables a further improvement in drainage capacity.

[0069] In the elbow 5, if the angle between the center lines A11 and A12 of the inlets 51 and 52 in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50 is θ [°], and the distance between the intersection point P1 of the center lines A11 and A12 of the inlets 51 and 52 and the openings 501 and 502 in the cross-section in the plane including the pipe axis A10 of the bent pipe portion 50 is Z [mm], then Z satisfies the following equation.

Equation

[0070] In the elbow 5, δ and θ are set such that ζ has a minimum value with respect to the change in Z. This configuration enables a further improvement in drainage capacity.

[0071] In the elbow 5, ζ is less than or equal to 1.1 times the minimum value. This configuration enables a further improvement in drainage capacity.

[0072] In the elbow 5, ζ is the minimum value. This configuration enables a further improvement in drainage capacity.

[0073] In the elbow 5, when the angle between the center lines A11 and A12 of the inlets 51 and 52 in the cross section in the plane including the pipe axis A10 of the curved pipe portion 50 is θ [°], θ is 97° or more and 135° or less. This configuration can suppress a decrease in drainage capacity due to a temperature difference in a rain gutter system including the elbow, and further improve stability.

[0074] In the elbow 5, θ is 100° or more. This configuration can further suppress a decrease in drainage capacity due to a temperature difference in a rain gutter system including the elbow.

[0075] In the elbow 5, θ is 128° or less. This configuration can further improve stability in a rain gutter system including the elbow.

[0076] In the elbow 5, θ is 105°. This configuration can further suppress a decrease in drainage capacity due to a temperature difference in a rain gutter system including the elbow, and in addition, can further improve stability.

[0077] In the elbow 5, δ satisfies the reference dimension of the nominal diameter defined in JIS K 6739. This configuration enables an improvement in the versatility of the elbow. When δ corresponds to the nominal diameter of 75 mm or 100 mm defined in JIS K 6739, R is preferably 180 mm or more. In this case, a further improvement in drainage capacity is enabled. When δ corresponds to the nominal diameter of 125 mm defined in JIS K 6739, R is preferably 200 mm or more. In this case, a further improvement in drainage capacity is enabled.

[0078] In the elbow 5, the material of the curved pipe portion 50 is rigid polyvinyl chloride. This configuration enables a further improvement in drainage capacity.

[0079] From another perspective, the elbow 5 described above includes a curved pipe portion 50 having openings 501 and 502 at both ends, and receiving ports 51 and 52 provided at both ends of the curved pipe portion 50, respectively. In a cross-section in a plane including the pipe axis A10 of the curved pipe portion 50, the first intersection point P1 of the center lines A11 and A12 of the receiving ports 51 and 52 is on the side opposite to the pipe axis A10 of the curved pipe portion 50 with respect to the first inner wall surface 50d of the outer peripheral portion 50c of the curved pipe portion 50. In a cross-section in a plane including the pipe axis A10, the second intersection point P2 of the tangent lines L11 and L12 of the pipe axis A10 at the openings 501 and 502 of the curved pipe portion 50 is closer to the first inner wall surface 50d than the pipe axis A10. In a cross-section in a plane including the pipe axis A10, the radius of curvature of the second inner wall surface 50b of the inner peripheral portion 50a of the curved pipe portion 50 is 130 [mm] or more. This configuration enables an improvement in drainage capacity.

[0080] In the elbow 5, in a cross-section in a plane including the pipe axis A10, the second intersection point P2 is between the intermediate line M1 between the pipe axis A10 and the first inner wall surface 50d and the first inner wall surface 50d. This configuration enables a further improvement in drainage capacity.

[0081] The rain gutter system 1 described above includes a vertical gutter 3 fixed to the wall surface 12 of the building 10, a downspout 4 between the rainwater outlet 2b from the building 10 and the vertical gutter 3, a first elbow 5A connecting the upstream end 4a of the downspout 4 to the rainwater outlet 2b, and a second elbow 5B connecting the downstream end 4b of the downspout 4 to the upstream end 3a of the vertical gutter 3. Both the first elbow 5A and the second elbow 5B are the above-described elbow 5. This configuration enables an improvement in drainage capacity.

[0082] [2. Modification Example] The embodiments of the present disclosure are not limited to the above embodiments. The above embodiments can be variously modified according to design and the like as long as the problems of the present disclosure can be achieved. Below, modification examples of the above embodiments are listed. The modification examples described below can be applied in appropriate combinations.

[0083] In one modification example, the elbow 5 is not limited to the configurations shown in FIGS. 2, 4, and 5, and the above parameter ζ may be less than 0.14 and r may be 130 mm or more.

[0084] In a modification, the first elbow 5A and the second elbow 5B do not necessarily have the same shape. However, when α of the first elbow 5A and the second elbow 5B is equal, the installation of the rain gutter system 1 becomes easier. When the inlets 51 and 52 of the first elbow 5A and the second elbow 5B have the same shape, the installation of the rain gutter system 1 becomes easier.

[0085] In a modification, the material of the elbow 5 does not necessarily have to be rigid polyvinyl chloride. The material of the elbow 5 may be determined according to the requirements for the rain gutter system 1, and for example, it may be metal.

[0086] In a modification, δ of the elbow 5 does not necessarily have to satisfy the standard dimension of the nominal diameter defined in JIS K 6739. D, d, and l of the elbow 5 do not necessarily have to be set in accordance with the provisions of JIS K 6739.

[0087] In a modification, in the rain gutter system 1, at least one of the first elbow 5A and the second elbow 5B may be the above-described elbow 5. Also in this configuration, it is possible to improve the drainage capacity.

[0088] In a modification, the rain gutter system 1 may not include the eaves gutter 2. For example, when the building 10 has a structure with a drop-off such as a balcony, the first elbow 5A of the rain gutter system 1 may be connected to the drop-off of the building 10.

[0089] [3. Aspect] As is clear from the above embodiments and modifications, the present disclosure includes the following aspects. Hereinafter, for the sole purpose of clarifying the correspondence with the embodiments, reference numerals are attached in parentheses. Note that, in consideration of the readability of the text, the description of the reference numerals in parentheses may be omitted after the second time.

[0090] The first aspect is an elbow (5), comprising a curved pipe portion (50) having openings (501, 502) at both ends, and receiving ports (51, 52) provided at both ends of the curved pipe portion (50), respectively. Let ζ be a parameter indicating the fluid flow resistance in the curved pipe portion (50), then ζ is represented by the following formula.

Equation

[0091] The second aspect is an elbow (5) based on the first aspect. In the second aspect, ζ is less than 0.12. This aspect enables further improvement of the drainage capacity.

[0092] The third aspect is an elbow (5) based on the first or second aspect. In the third aspect, let the angle between the center lines (A11, A12) of the receiving ports (51, 52) in the cross-section in the plane including the pipe axis (A10) of the curved pipe portion (50) be θ [°], and the distance between the intersection point (P1) of the center lines (A11, A12) of the receiving ports (51, 52) and the openings (501, 502) in the cross-section in the plane including the pipe axis (A10) of the curved pipe portion (50) be Z [mm], then Z satisfies the following formula.

Equation

[0093] The fourth aspect is the elbow (5) based on the third aspect. In the fourth aspect, δ and θ are set such that ζ has a minimum value with respect to the change in Z. This aspect enables further improvement of the drainage capacity.

[0094] The fifth aspect is the elbow (5) based on the fourth aspect. In the fifth aspect, ζ is 1.1 times or less of the minimum value. This aspect enables further improvement of the drainage capacity.

[0095] The sixth aspect is the elbow (5) based on the fourth aspect. In the sixth aspect, ζ is the minimum value. This aspect enables further improvement of the drainage capacity.

[0096] The seventh aspect is the elbow (5) based on any one of the third to sixth aspects. In the seventh aspect, when the angle between the center lines (A11, A12) of the inlets (51, 52) in the cross-section in the plane including the pipe axis (A10) of the curved pipe portion (50) is θ [°], θ is 97° or more and 135° or less. This aspect can suppress the decrease in the drainage capacity due to the temperature difference in the rain gutter system provided with the elbow, and further improve the stability.

[0097] The eighth aspect is the elbow (5) based on the seventh aspect. In the eighth aspect, θ is 100° or more. This aspect can further suppress the decrease in the drainage capacity due to the temperature difference in the rain gutter system provided with the elbow.

[0098] The ninth aspect is the elbow (5) based on the seventh or eighth aspect. In the ninth aspect, θ is 128° or less. This aspect can further improve the stability in the rain gutter system provided with the elbow.

[0099] The 10th aspect is the elbow (5) based on the 7th aspect. In the 10th aspect, θ is 105°. This aspect can further suppress the decrease in drainage capacity due to temperature difference in a rain gutter system provided with an elbow, and in addition, can further improve the stability.

[0100] The 11th aspect is the elbow (5) based on any one of the 1st to 10th aspects. In the 11th aspect, δ satisfies the reference dimension of the nominal diameter defined in JIS K 6739. This aspect enables the improvement of the versatility of the elbow.

[0101] The 12th aspect is the elbow (5) based on the 11th aspect. In the 12th aspect, δ corresponds to the nominal diameter of 75 mm or 100 mm defined in JIS K 6739. R is 180 mm or more. This aspect enables the further improvement of the drainage capacity.

[0102] The 13th aspect is the elbow (5) based on the 11th aspect. In the 13th aspect, δ corresponds to the nominal diameter of 125 mm defined in JIS K 6739. R is 200 mm or more. This aspect enables the further improvement of the drainage capacity.

[0103] The 14th aspect is the elbow (5) based on any one of the 1st to 13th aspects. In the 14th aspect, the material of the curved pipe portion (50) is rigid polyvinyl chloride. This aspect enables the further improvement of the drainage capacity.

[0104] The 15th aspect is a rain gutter system (1), comprising a vertical gutter (3) fixed to the wall surface (12) of a building (10), a downspout (4) between a rainwater outlet (2b) from the building (10) and the vertical gutter (3), a first elbow (5A) connecting an upstream end (4a) of the downspout (4) to the rainwater outlet (2b), and a second elbow (5B) connecting a downstream end (4b) of the downspout (4) to an upstream end (3a) of the vertical gutter (3). At least one of the first elbow (5A) and the second elbow (5B) is an elbow (5) based on any one of the 1st to 14th aspects. This aspect enables improvement of drainage capacity.

[0105] The above 2nd to 14th aspects are optional elements.

Industrial Applicability

[0106] The present disclosure is applicable to elbows and rain gutter systems. Specifically, the present disclosure is applicable to elbows used for installing downspouts and rain gutter systems including elbows.

Explanation of Reference Numerals

[0107] 1 Rain gutter system 2b Rainwater outlet 3 Vertical gutter 3a Upstream end 4 Downspout 4a Upstream end 4b Downstream end 5 Elbow 5A First elbow 5B Second elbow 50 Curved pipe portion 50a Inner peripheral portion 50b Inner wall surface (second inner wall surface) 50c Outer peripheral portion 50d Inner wall surface (first inner wall surface) 501, 502 Openings 51, 52 Inlets A10 Pipe axis A11, A12 Center lines L11, L12 Tangent lines P1 Intersection point (First intersection point) P2 Intersection point (Second intersection point) M1 Intermediate line 10 Building 12 Wall surface

Claims

1. A curved pipe section having openings at both ends, Receiving ports respectively provided at both ends of the curved pipe section, Comprising, When the parameter indicating the fluid flow resistance in the curved pipe section is ζ, ζ is, 【Number 1】 Represented by, δ is the diameter [mm] of the opening of the curved pipe section, R is the radius of curvature [mm] of the pipe axis of the curved pipe section, ρ is the angle [°] between the tangents of the pipe axis at the opening of the curved pipe section in the cross-section in the plane including the pipe axis of the curved pipe section, α is the angle [°] between the center line of the receiving port and the tangent in the cross-section in the plane including the pipe axis of the curved pipe section, ζ is less than 0.14, Elbow.

2. ζ is less than 0.12, The elbow according to claim 1.

3. Let the angle between the center lines of the receiving ports in the cross-section in the plane including the pipe axis of the curved pipe section be θ [°], Let the distance between the intersection of the center lines of the receiving ports and the opening in the cross-section in the plane including the pipe axis of the curved pipe section be Z [mm], then Z is, 【Number 2】 Satisfying, The elbow according to claim 1 or 2.

4. δ and θ are set such that ζ has a minimum value with respect to the change in Z, The elbow according to claim 3.

5. ζ is less than or equal to 1.1 times the minimum value, The elbow according to claim 4.

6. ζ is the minimum value, The elbow according to claim 4.

7. θ is 97° or more and 135° or less, The elbow according to any one of claims 3 to 6.

8. θ is 100° or more, The elbow according to claim 7.

9. θ is 128° or less, The elbow according to claim 7 or 8.

10. θ is 105°, The elbow according to claim 7.

11. δ satisfies the reference dimension of the nominal diameter defined in JIS K 6739, The elbow according to any one of claims 1 to 10.

12. δ corresponds to the nominal diameter of 75 mm or 100 mm defined in JIS K 6739, R is 180 mm or more, The elbow according to claim 11.

13. δ corresponds to the nominal diameter of 125 mm defined in JIS K 6739, R is 200 mm or more, The elbow according to claim 11.

14. The material of the curved pipe section is rigid polyvinyl chloride, The elbow according to any one of claims 1 to 13.

15. A vertical drainpipe fixed to the wall surface of a building, A downspout between the rainwater outlet from the building and the vertical drainpipe, A first elbow connecting the upstream end of the downspout to the outlet, A second elbow connecting the downstream end of the downspout to the upstream end of the vertical pipe, comprising, wherein at least one of the first elbow and the second elbow is the elbow according to any one of claims 1 to 14, a rain gutter system.

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