Piping member and backflow prevention valve

Abstract

To prevent wastewater from flowing backward into a piping member when wastewater flows backward, and to allow wastewater to flow easily when wastewater is not flowing backward.SOLUTION: A piping member 10 comprises a main body 11 having a main body cylindrical portion 15 in which a drain outlet 44 through which wastewater passes is formed, and backflow prevention means 50 capable of closing the drain outlet 44 when wastewater passing through the drain outlet 44 flows backward. The backflow prevention means 50 has a valve body 55 opening and closing the drain outlet 44, and an opening force applying mechanism 57 applying an opening force to the valve body 55 in the direction of opening the drain outlet 44, at least at times other than backflow when wastewater passing through the drain outlet 44 flows backward. The valve body 55 is configured to close the drain outlet 44 when backflow occurs, by applying backflow pressure which is the pressure of the wastewater when the wastewater passing through the drain outlet 44 flows backward.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a piping component (for example, a catch basin, a manhole, a pipe joint, etc.) and a check valve. [Background technology]

[0002] For example, Patent Document 1 discloses a check valve attached to a catch basin. An inlet pipe is connected to pass through the catch basin. The check valve is disposed in the catch basin and includes a valve pipe connected to the inlet pipe and a valve body that opens and closes the valve pipe.

[0003] In this catch basin, the valve body closes the valve pipe except when wastewater flows into the catch basin from the inlet pipe, and the check valve closes the inlet pipe. Because the check valve closes the inlet pipe in this way, when wastewater backflows into the catch basin, the valve body blocks the wastewater, making it difficult for it to flow into the inlet pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5084877 Summary of the Invention [Problem to be solved by the invention]

[0005] In the invention disclosed in Patent Document 1, as described above, the inlet pipe is closed by the check valve except when wastewater flows from the inlet pipe into the catch basin. Therefore, when wastewater flows into the inlet pipe, the wastewater pushes the check valve, causing it to open from the inlet pipe. At this time, a level of wastewater pressure is required to open the check valve from the inlet pipe, which could make it difficult for the wastewater to flow.

[0006] The present invention has been made in consideration of these points, and its purpose is to provide a piping component and a backflow prevention valve that make it difficult for wastewater to flow back into the piping component when the wastewater backflows, and that makes it easier for the wastewater to flow when the wastewater is not backflowing. [Means for solving the problem]

[0007] The piping member according to the present invention comprises a main body having a tubular main body portion formed with a drain port through which wastewater passes, and backflow prevention means capable of closing the drain port when wastewater passing through the drain port backflows. The backflow prevention means comprises a valve body that opens and closes the drain port, and an opening force applying mechanism that applies an opening force to the valve body in a direction to open the drain port at least during times other than backflow when wastewater passing through the drain port backflows. The valve body is configured to close the drain port when backflow occurs by applying backflow pressure, which is the pressure of wastewater when passing through the drain port backflows.

[0008] According to the piping member, when backflow is not occurring, the opening force exerted by the opening force exerting mechanism is applied to the valve body, thereby keeping the drain outlet open from the valve body. Therefore, when backflow is not occurring, it is possible to facilitate the flow of wastewater through the drain outlet. On the other hand, when backflow occurs, backflow pressure is exerted on the valve body, causing the valve body to close the drain outlet. This makes it difficult for the backflowing wastewater to flow through the drain outlet when backflow occurs.

[0009] According to another preferred aspect of the present invention, the drain port is an outlet through which wastewater passes when it flows out of the main body.

[0010] According to the above aspect, the valve body of the backflow prevention means can close the outlet when backflow occurs, thereby making it difficult for backflowing wastewater to flow into the tubular main body portion of the main body through the outlet.

[0011] According to another preferred aspect of the present invention, the valve body is configured to close the drain outlet when the sum of the backflow pressure and the weight of the valve body is greater than the opening force.

[0012] According to the above aspect, when the backflow pressure increases and the sum of the backflow pressure and the weight of the valve body becomes greater than the opening force, the valve body can close the drain outlet. Therefore, depending on the magnitude of the backflow pressure, it becomes more difficult for the backflow wastewater to pass through the drain outlet.

[0013] According to another preferred aspect of the present invention, the opening force applying mechanism includes a valve-side magnetic body provided on the valve body and a body-side magnetic body fixed to the body, and the valve-side magnetic body and the body-side magnetic body generate the opening force by magnetic forces that repel or attract each other.

[0014] According to the above aspect, an opening force for the valve can be generated by using the magnetic force of repulsion or attraction between the magnetic body on the valve body side and the magnetic body on the main body side, so that the valve body can be opened from the drain outlet when backflow is not occurring.

[0015] According to another preferred aspect of the present invention, the backflow prevention means includes a backflow prevention body attached to the drain outlet and having a communication port formed therein that communicates with the drain outlet. The valve body is configured to open and close the drain outlet by opening and closing the communication port. The body-side magnetic body is provided on a portion of the backflow prevention body that faces the valve body-side magnetic body when the valve body closes the communication port. The valve body-side magnetic body and the body-side magnetic body generate the opening force by the magnetic forces that repel each other.

[0016] According to the above aspect, by arranging the main body side magnetic body in the part of the backflow prevention main body that faces the valve body side magnetic body, an opening force can be generated on the valve body using the repulsive magnetic force between the valve body side magnetic body and the main body side magnetic body.

[0017] According to another preferred aspect of the present invention, the communication opening is inclined downwardly away from the drain opening.

[0018] According to the above aspect, when the valve element closes the communication port, the communication port can be closed while the valve element is tilted along the slope of the communication port, making it easier for the valve element to close the communication port during backflow.

[0019] According to another preferred aspect of the present invention, the main body has a drain tube portion connected to the drain outlet on the outside of the main body tube portion. The backflow prevention means has a backflow prevention body attached to the drain outlet and having a communication port formed therein that communicates with the drain outlet. The valve body is configured to open and close the drain outlet by opening and closing the communication port. The backflow prevention body is fitted into the drain tube portion. The backflow prevention means is provided between the backflow prevention body and the drain tube portion and has an annular elastic body that follows the circumferential direction of the backflow prevention body.

[0020] According to the above aspect, the annular elastic body can improve the sealing performance between the backflow prevention main body and the drain tube portion, thereby making it difficult for drainage water to leak between the backflow prevention main body and the drain tube portion.

[0021] According to another preferred aspect of the present invention, the elastic body has an upper portion and a lower portion that is positioned below the upper portion and extends further in the axial direction of the drain outlet than the upper portion.

[0022] According to the above aspect, wastewater flows easily to the lower portion of the backflow prevention body. Therefore, by extending the lower portion of the elastic body in the axial direction of the drain outlet, it is possible to further improve the sealing performance between the lower portion of the backflow prevention body, through which wastewater flows easily, and the drain tube portion.

[0023] According to another preferred aspect of the present invention, the main body has a tubular drain portion connected to the drain outlet on the outside of the tubular main body portion, the valve body is disposed within the tubular drain portion, and the valve body curves along the inner circumferential surface of the tubular drain portion when the drain outlet is open.

[0024] According to the above aspect, the valve body is curved along the inner circumferential surface of the drain tube portion, so that it is less likely to interfere with the drain tube portion when opening and closing the drain outlet. Furthermore, because the valve body opens the drain outlet while curved along the inner circumferential surface of the drain tube portion, the drain outlet can be opened more widely. Therefore, more wastewater can be discharged into the drain outlet when not in backflow.

[0025] The check valve of the present invention is a check valve that can close a drain outlet when wastewater passing through the drain outlet flows back in a piping member having a main body with a drain outlet through which wastewater passes. The check valve includes a valve body that opens and closes the drain outlet, and an opening force applying mechanism that applies an opening force to the valve body in a direction to open the drain outlet at least during times other than backflow when wastewater passing through the drain outlet flows back. The valve body is configured to close the drain outlet when backflow occurs by applying backflow pressure, which is the pressure of wastewater when passing through the drain outlet flows back. The check valve can achieve the same effects as the above-mentioned piping member. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a piping member and a check valve that make it difficult for wastewater to flow back into the piping member when the wastewater backflows, and that allows the wastewater to flow easily when the wastewater is not backflowing. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 2 is a plan view showing the catch basin according to the first embodiment. [Figure 2] 2 is a cross-sectional view of the catch basin taken along the line II-II in FIG. 1, showing the state of the valve body under normal conditions. FIG. [Figure 3] 2 and shows the state of the valve body during backflow. FIG. [Figure 4] 2 and shows the valve body in a state where it is fully opened. [Figure 5] FIG. [Figure 6]FIG. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. 10 shows a backflow prevention body. [Figure 10] FIG. 10 is a cross-sectional view showing the outlet tube portion of the catch basin according to the second embodiment, and is a schematic diagram showing a state in which the valve body opens the outlet port. [Figure 11] FIG. 10 is a cross-sectional view showing the outlet tube portion of the catch basin according to the second embodiment, and is a schematic diagram showing a state in which the valve body closes the outlet port. [Figure 12] FIG. 10 is a cross-sectional view showing the outlet tube portion of the catch basin according to the third embodiment, and is a schematic diagram showing a state in which the valve body opens the outlet port. [Figure 13] FIG. 10 is a cross-sectional view showing the outlet tube portion of the catch basin according to the third embodiment, and is a schematic diagram showing a state in which the valve body closes the outlet port. [Figure 14] FIG. 10 is a cross-sectional view showing the outlet tube portion of the catch basin according to the fourth embodiment, and is a schematic diagram showing a state in which the valve body opens the outlet port. [Figure 15] FIG. 10 is a cross-sectional view showing the outlet tube portion of the catch basin according to the fourth embodiment, and is a schematic diagram showing a state in which the valve body closes the outlet port. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, a drainage system equipped with a drain inlet, which is an example of a piping member according to an embodiment of the present invention, will be described with reference to the drawings. However, the embodiment described below is merely one embodiment of the present invention, and is not intended to limit the present invention.

[0029] First Embodiment FIG. 1 is a plan view showing a drainage system 100 equipped with a catch basin 10 according to a first embodiment. The drainage system 100 is a system through which wastewater flows. Here, wastewater is a general term that includes at least sewage and rainwater. Sewage is water discharged from toilets, bathtubs, kitchen sinks, etc., and cannot be discharged directly into rivers. Rainwater is water resulting from natural phenomena such as rainfall, and can be discharged directly into rivers. Here, the drainage system 100 is a system through which sewage flows. However, the drainage system 100 may also be a system through which rainwater flows.

[0030] In this embodiment, the drainage system 100 is buried underground. However, the drainage system 100 may also be disposed above ground (for example, inside a building). As shown in Fig. 1, the drainage system 100 includes a first inlet pipeline 101, a second inlet pipeline 102, a third inlet pipeline 103, an outlet pipeline 104, and a catch basin 10.

[0031] Here, a pipeline is a structure made up of one or more pipes and one or more joints connecting the pipes, through which wastewater flows. Drainage facilities (not shown) are connected to the upstream ends of each of the first inlet pipeline 101 to the third inlet pipeline 103. The drainage facilities are facilities into which wastewater is discharged, such as toilets, kitchens, and bathrooms. The first inlet pipeline 101 to the third inlet pipeline 103 are pipelines into which wastewater discharged from the drainage facilities flows.

[0032] The outlet pipeline 104 is disposed downstream of the first inlet pipeline 101, the second inlet pipeline 102, and the third inlet pipeline 103. A main sewer pipe (not shown) is connected to the downstream end of the outlet pipeline 104. Here, the wastewater flowing through the outlet pipeline 104 flows out into the main sewer pipe. More specifically, the wastewater flowing in from the first inlet pipeline 101 to the third inlet pipeline 103 flows out from the outlet pipeline 104 toward the main sewer pipe.

[0033] Next, we will explain the catch basin 10, which is an example of a piping component. Wastewater flowing through the first inlet pipeline 101 to the third inlet pipeline 103 flows into the catch basin 10, and the wastewater that has flowed into the catch basin 10 flows to the outlet pipeline 104. Here, as shown in FIG. 1 , the catch basin 10 is arranged between the first inlet pipeline 101 and the outlet pipeline 104, between the second inlet pipeline 102 and the outlet pipeline 104, and between the third inlet pipeline 103 and the outlet pipeline 104. In this embodiment, the catch basin 10 is buried underground, but it may also be arranged above ground. The catch basin 10 is a so-called public catch basin.

[0034] FIG. 2 is a cross-sectional view of the catch basin 10 taken along line II-II in FIG. 1, showing the state of the valve element 55 under normal conditions. FIG. 3 is a view equivalent to FIG. 2, showing the state of the valve element 55 under backflow. FIG. 4 is a view equivalent to FIG. 2, showing the valve element 55 in its maximum open state. As shown in FIG. 2, the catch basin 10 includes a main body 11 and a backflow prevention means 50. The main body 11 is a cylindrical body with a bottom and an internal space. The configuration of the main body 11 is not particularly limited. In this embodiment, the main body 11 includes a main body tubular portion 15, an inspection tubular portion 16, a first inlet tubular portion 21, a second inlet tubular portion 22 (see FIG. 1), a third inlet tubular portion 23 (see FIG. 1), and an outlet tubular portion 24. In the following description, the side closer to the center C1 (see FIG. 1) of the main body 11 is referred to as the inside, and the side away from the center C1 of the main body 11 is referred to as the outside.

[0035] The main body tubular portion 15 is a tubular member that extends vertically. The configuration of the main body tubular portion 15 is not particularly limited. Here, the main body tubular portion 15 is a tubular member that opens upward and has a bottom. The main body tubular portion 15 has a bottom wall portion 30 and a side wall portion 31. The bottom wall portion 30 forms the bottom portion of the main body tubular portion 15. The side wall portion 31 is a tubular member that extends vertically and stands up from the bottom wall portion 30. The side wall portion 31 extends upward from the edge of the bottom wall portion 30.

[0036] The inspection tube portion 16 is cylindrical and extends vertically above the main body cylindrical portion 15. The inspection tube portion 16 is connected to the upper end of the main body cylindrical portion 15 (here, the upper end of the side wall portion 31). The inspection tube portion 16 opens upward, and this opening in the inspection tube portion 16 forms an inspection hatch 35. That is, the inspection hatch 35 is formed at the upper end of the inspection tube portion 16 and opens upward. In this embodiment, the inspection tube portion 16 is a single member together with the main body cylindrical portion 15, but it may also be a separate member from the main body cylindrical portion 15 and assembled to the main body cylindrical portion 15.

[0037] The main body 11 is formed with a first inlet 41, a second inlet 42, a third inlet 43, and an outlet 44. Wastewater passes through the first inlet 41, the second inlet 42, the third inlet 43, and the outlet 44. The first inlet 41, the second inlet 42, and the third inlet 43 are portions through which wastewater flows into the main body 11 of the catch basin 10. The outlet 44 is a portion through which wastewater flows out of the main body 11 of the catch basin 10. In this embodiment, the first inlet 41, the second inlet 42, the third inlet 43, and the outlet 44 are formed in the side wall portion 31 of the cylindrical main body 15. Here, the first inlet 41, the second inlet 42, the third inlet 43, and the outlet 44 open toward the side, but the opening direction is not particularly limited. In this embodiment, the outlet 44 is an example of a drain port through which wastewater passes in the present invention.

[0038] In this embodiment, as shown in FIG. 1 , the first inlet 41 and the outlet 44 face each other across the center C1 of the main body 11. The second inlet 42 and the third inlet 43 face each other across the center C1 of the main body 11. Here, in a plan view, the central axis of the first inlet 41 coincides with the central axis of the outlet 44. Here, in a plan view, the central axis of the second inlet 42 coincides with the central axis of the third inlet 43. Here, the second inlet 42 and the third inlet 43 are formed closer to the first inlet 41 than the center C1 of the main body 11. The opening area of ​​the outlet 44 is larger than the opening areas of the first inlet 41, the second inlet 42, and the third inlet 43. Furthermore, as shown in FIG. 2 , the lower end of the outlet 44 is positioned higher than the lower ends of the first inlet 41 and the second inlet 42. Although not shown, the lower end of the outlet 44 is positioned higher than the lower end of the third inlet 43. However, the relative positional relationship, opening direction, size, etc. of the first inlet 41, the second inlet 42, the third inlet 43 and the outlet 44 are not particularly limited.

[0039] In this embodiment, as shown in Fig. 2, an invert 46 is formed on the bottom wall 30 of the tubular main body 15. The invert 46 is formed so as to be recessed downward on the upper surface of the bottom wall 30. The invert 46 is disposed at a position lower than the first inlet 41, the second inlet 42, and the third inlet 43. The invert 46 slopes downward toward the outlet 44. Therefore, wastewater that flows into the main body 11 from the first inlet 41, the second inlet 42, and the third inlet 43 reaches the invert 46 and flows along the invert 46 toward the outlet 44.

[0040] The first inlet tube 21, the second inlet tube 22, the third inlet tube 23, and the outlet tube 24 are connected to the outside of the tubular main body 15. Here, the first inlet tube 21 is connected to the first inlet 41. The downstream end of the first inlet tube 21 is connected to the first inlet 41. As shown in FIG. 1 , the upstream end of the first inlet tube 21 is connected to the downstream end of the first inlet pipe 101. The second inlet tube 22 is connected to the second inlet 42. The downstream end of the second inlet tube 22 is connected to the second inlet 42. The upstream end of the second inlet tube 22 is connected to the downstream end of the second inlet pipe 102. The third inlet tube 23 is connected to the third inlet 43. The downstream end of the third inlet tube 23 is connected to the third inlet 43. The upstream end of the third inlet tubular portion 23 is connected to the downstream end of the third inlet pipe 103. As shown in FIG. 2, the outlet tubular portion 24 is connected to the outlet port 44. The upstream end of the outlet tubular portion 24 is connected to the outlet port 44. As shown in FIG. 1, the upstream end of the outlet pipe 104 is connected to the downstream end of the outlet tubular portion 24. In this embodiment, the first inlet tubular portion 21, the second inlet tubular portion 22, the third inlet tubular portion 23, and the outlet tubular portion 24 are each formed integrally with the main tubular portion 15, but they may also be separate bodies that are assembled to the main tubular portion 15. In this embodiment, the outlet tubular portion 24 is an example of a drain tubular portion connected to a drain outlet of the present invention.

[0041] Next, the backflow prevention means 50 according to this embodiment will be described. As shown in FIG. 3, the backflow prevention means 50 prevents wastewater from backflowing in the catch basin 10. The backflow prevention means 50 is an example of a backflow prevention valve according to the present invention. Here, the backflow prevention means 50 is provided at the outlet 44 and prevents wastewater from backflowing at the outlet 44. In other words, the backflow prevention means 50 prevents wastewater from backflowing from the outlet pipe 104 through the outlet 44 into the main body 11 of the catch basin 10. In this embodiment, as shown in FIG. 2, the direction in which wastewater flows under normal circumstances is referred to as the normal direction D1. On the other hand, as shown in FIG. 3, the direction in which wastewater flows when wastewater backflows (in other words, when not under normal circumstances) is referred to as the backflow direction D2. The backflow direction D2 is the direction opposite to the normal direction D1. At the outlet 44, the normal direction D1 refers to the direction in which wastewater flows from the main body 11 to the outlet tube portion 24 (in other words, the outlet pipe 104). At the outlet 44, the reverse flow direction D2 is the direction in which wastewater flows from the outlet cylindrical portion 24 into the main body 11.

[0042] In this embodiment, the backflow prevention means 50 is configured to open the outlet 44 during normal times, as shown in Fig. 2, and to close the outlet 44 during backflow, as shown in Fig. 3. Here, normal times refer to times other than backflow, and include times when wastewater is flowing in the normal direction D1 and times when wastewater is not flowing.

[0043] FIG. 5 is a perspective view showing the backflow prevention means 50. FIG. 6 is a front view showing the backflow prevention means 50. As shown in FIG. 5, the backflow prevention means 50 has a backflow prevention main body 51, an elastic body 53, a valve body 55, and an opening force imparting mechanism 57. As shown in FIG. 2, the backflow prevention main body 51 is attached to the outlet 44 of the main body 11. Here, the backflow prevention main body 51 is fitted into the outlet tubular portion 24 connected to the outlet 44. The backflow prevention main body 51 is cylindrical and is fitted into the outlet tubular portion 24.

[0044] In this embodiment, a communication port 60 is formed in the backflow prevention body 51. The communication port 60 is formed to penetrate the backflow prevention body 51 and opens in the same direction as the outflow port 44, in this case, facing sideways. The communication port 60 communicates with the outflow port 44 when the backflow prevention body 51 is fitted into the outflow tubular portion 24. Here, the end face of the backflow prevention body 51 on the normal direction D1 side where the communication port 60 is formed (in other words, the downstream end face) is inclined downward, away from the outflow port 44. Therefore, the communication port 60 formed in the backflow prevention body 51 is inclined downward, away from the outflow port 44. Here, the inclination angle of the communication port 60 (for example, the inclination angle from an axis parallel to the normal direction D1) becomes smaller downward. The end face of the backflow prevention body 51 on the normal direction D1 side where the communication port 60 is formed is curved.

[0045] In this embodiment, as shown in Fig. 5, the backflow prevention main body 51 is provided with an abutment plate 62. As shown in Fig. 2, the abutment plate 62 is provided at the end of the backflow prevention main body 51 on the tubular main body portion 15 side and protrudes upward from the backflow prevention main body 51. Here, when the backflow prevention main body 51 is fitted into the tubular outflow portion 24, the abutment plate 62 abuts against the inner circumferential surface of the side wall portion 31 of the tubular main body portion 15 of the main body 11. This abutment of the abutment plate 62 with the inner circumferential surface of the side wall portion 31 makes it difficult for the backflow prevention main body 51 to come off in the normal direction D1 relative to the tubular outflow portion 24. In addition, the abutment plate 62 makes it possible to align the backflow prevention main body 51 with respect to the tubular outflow portion 24.

[0046] In this embodiment, as shown in Fig. 2, an elastic body 53 is provided between the backflow prevention main body 51 and the outflow tubular portion 24. As shown in Fig. 5, the elastic body 53 is annular and has a shape that follows the circumferential direction of the backflow prevention main body 51. Here, the elastic body 53 is attached to the outer circumferential surface of the backflow prevention main body 51. The elastic body 53 is formed, for example, from an elastic member having a predetermined elastic force. For example, rubber can be used as the elastic member. As the rubber, synthetic rubber (for example, ethylene propylene rubber (EPDM)) can be suitably used.

[0047] In this embodiment, the length of the elastic body 53 in the axial direction of the outflow port 44 (here, the same direction as the normal direction D1) may vary depending on the portion. Here, as shown in FIG. 6 , the elastic body 53 has an upper portion 53a and a lower portion 53b. For example, when the elastic body 53 is divided into two (here, approximately equal halves) vertically, the upper portion is the upper portion 53a and the lower portion is the lower portion 53b. The upper portion 53a and the lower portion 53b have different lengths in the normal direction D1. In this embodiment, the lower portion 53b is longer in the normal direction D1 than the upper portion 53a. As shown in FIG. 2 , the lower portion 53b is disposed below the upper portion 53a and extends further in the axial direction of the outflow port 44 than the upper portion 53a. Here, the lower portion 53b of the elastic body 53 extends further inward of the main body 11 than the backflow prevention main body 51.

[0048] As shown in FIGS. 2 and 3 , the valve element 55 opens and closes the outflow port 44. In this embodiment, the valve element 55 is provided in the backflow prevention main body 51 and is configured to be able to open and close the communication port 60. The valve element 55 can open and close the outflow port 44 by opening and closing the communication port 60. The valve element 55 is configured to open and close the communication port 60 with its upper end as an axis. In this embodiment, a hinge 64 is provided at the upper edge of the communication port 60 in the backflow prevention main body 51. The valve element 55 is provided on the hinge 64 and is attached to the backflow prevention main body 51 via the hinge 64. The valve element 55 is configured to be able to open and close the communication port 60 and the outflow port 44 with the hinge 64 as an axis. Note that in this embodiment, there is one hinge 64, but the number of hinges 64 is not particularly limited.

[0049] 7 and 8 are diagrams showing the valve element 55. FIG. 7 is a view of the valve element 55 from below when the valve element 55 closes the outflow port 44. FIG. 8 shows the surface of the valve element 55 facing the backflow prevention main body 51. In this embodiment, as shown in FIG. 7, the valve element 55 is curved. As shown in FIG. 2, the valve element 55 is curved so as to protrude away from the main body 11 as it approaches the center in direction D3 (see FIG. 7) perpendicular to the normal direction D1 in a plan view. Here, the valve element 55 is disposed within the tubular outflow portion 24. As shown in FIG. 4, the valve element 55 curves along the inner circumferential surface of the tubular outflow portion 24 when the outflow port 44 is open. Furthermore, as shown in FIG. 3, the valve element 55 is disposed so as to tilt along the inclined communication port 60 when the communication port 60 is closed. As shown in FIG. 8, the valve body 55 has a width (length in a direction D3 perpendicular to the normal direction D1) that decreases downward (in other words, as it moves away from the hinge 64).

[0050] In this embodiment, a seal member 56 is provided on the periphery of the surface of the valve disc 55 on the outlet 44 side. As shown in FIG. 3 , when the valve disc 55 closes the communication port 60, the seal member 56 is interposed between the valve disc 55 and the backflow prevention main body 51 and comes into contact with the portion of the backflow prevention main body 51 that forms the communication port 60. The seal member 56 is made of an elastic material such as rubber (for example, synthetic rubber such as EPDM). This seal member 56 can improve the sealing performance between the valve disc 55 and the backflow prevention main body 51 when the valve disc 55 closes the communication port 60.

[0051] The opening force imparting mechanism 57 is a mechanism that imparts an opening force to the valve disc 55 in a direction that opens the outflow port 44 when there is no backflow, i.e., during normal operation. This opening force is different from the force of gravity acting on the valve disc 55. The direction of the opening force with respect to the valve disc 55 is normal direction D1, which is different from the direction of gravity acting on the valve disc 55 (downward in this case). In this way, by applying an opening force to the valve disc 55 in a direction that opens the outflow port 44, in this case normal direction D1, the valve disc 55 can open the communication port 60 during normal operation, as shown in FIG. 2 . The specific configuration for the opening force imparting mechanism 57 to generate the opening force is not particularly limited. In this embodiment, the opening force imparting mechanism 57 generates the opening force using magnetic force.

[0052] 2, the opening force applying mechanism 57 has a valve-side magnetic body 71 and a main body-side magnetic body 72. The valve-side magnetic body 71 and the main body-side magnetic body 72 generate magnetic forces and are formed, for example, by magnets. In this embodiment, the valve-side magnetic body 71 and the main body-side magnetic body 72 are arranged so as to generate a repulsive force that repels each other. This repulsive force serves as an opening force that normally opens the valve body 55 from the outlet 44.

[0053] In this embodiment, the valve-element side magnetic body 71 is provided on the valve element 55. Here, as shown in FIG. 8, the valve-element side magnetic body 71 is provided on the upper part of the surface of the valve element 55 facing the backflow prevention main body 51. The number of valve-element side magnetic bodies 71 is not particularly limited. In this embodiment, there are two valve-element side magnetic bodies 71, but there may be one, or three or more. The two valve-element side magnetic bodies 71 are arranged to sandwich a central axis L1 that passes through the center of the valve element 55 in the direction D3. One valve-element side magnetic body 71 is arranged on one side of the central axis L1. The other valve-element side magnetic body 71 is arranged on the other side of the central axis L1.

[0054] 2, the main body side magnetic body 72 is fixed to the main body 11 of the catch basin 10. In other words, the main body side magnetic body 72 is fixed so as not to move when the valve body 55 is opening or closing. In this embodiment, the main body side magnetic body 72 is provided on the backflow prevention main body 51. The main body side magnetic body 72 is provided on a portion of the backflow prevention main body 51 that faces the valve body side magnetic body 71 when the valve body 55 closes the communication port 60.

[0055] FIG. 9 is a diagram showing the backflow prevention main body 51. FIG. 9 shows the valve disc 55 side of the backflow prevention main body 51. Here, as shown in FIG. 9, the valve disc-side magnetic body 71 is provided at a position overlapping the communication port 60 and is provided on the top of the backflow prevention main body 51. The number of main body-side magnetic bodies 72 is not particularly limited, but here, there are two, the same number as the number of valve disc-side magnetic bodies 71. The two main body-side magnetic bodies 72 are arranged on either side of the central axis L2 that passes through the center of the backflow prevention main body 51 in the direction D3. Here, the backflow prevention main body 51 is provided with attachment pieces 66 that protrude from the upper edge of the communication port 60 toward the inside of the communication port 60. There are two attachment pieces 66. The main body-side magnetic bodies 72 are attached to these attachment pieces 66.

[0056] As described above, in this embodiment, the valve-body-side magnetic body 71 and the main body-side magnetic body 72 are arranged so as to repel each other. Here, for example, if the surface of the valve-body-side magnetic body 71 facing the main body-side magnetic body 72 is an S pole, the surface of the main body-side magnetic body 72 facing the valve-body-side magnetic body 71 also becomes an S pole. Furthermore, for example, if the surface of the valve-body-side magnetic body 71 facing the main body-side magnetic body 72 is an N pole, the surface of the main body-side magnetic body 72 facing the valve-body-side magnetic body 71 also becomes an N pole.

[0057] In this embodiment, as shown in FIG. 3, during backflow, the valve element 55 is subjected to the pressure of the wastewater when the wastewater passing through the outlet 44 flows backward (referred to here as backflow pressure). The backflow pressure is pressure applied to the valve element 55 in the backflow direction D2. When this backflow pressure becomes large, the valve element 55 is configured to close the outlet 44. Here, even during backflow, an opening force in the normal direction D1 (see FIG. 2) is applied to the valve element 55 to resist the backflow pressure. Therefore, when the sum of the backflow pressure and the weight of the valve element 55 becomes larger than the opening force, that is, when the opening force < the backflow pressure + the weight of the valve element 55, the valve element 55 is configured to close the outlet 44.

[0058] The configuration of the drainage system 100 including the catch basin 10 according to this embodiment has been described above. Next, a method of using the drainage system 100 will be described.

[0059] As shown in FIG. 1 , in the drainage system 100, wastewater is normally discharged from the drainage equipment connected to the first inlet pipe 101 to the third inlet pipe 103. The wastewater discharged from the drainage equipment connected to the first inlet pipe 101 flows into the tubular main body 15 of the main body 11 through the first inlet pipe 101, the first inlet tubular portion 21, and the first inlet 41. The wastewater discharged from the drainage equipment connected to the second inlet pipe 102 flows into the tubular main body 15 through the second inlet pipe 102, the second inlet tubular portion 22, and the second inlet 42. Similarly, the wastewater discharged from the drainage equipment connected to the third inlet pipe 103 flows into the tubular main body 15 through the third inlet pipe 103, the third inlet tubular portion 23, and the third inlet 43. The wastewater that flows into the tubular main body 15 of the main body 11 flows along an invert 46 formed in the bottom wall 30 of the tubular main body 15 toward the outlet 44. Then, as shown in FIG. 2, the wastewater passes through the outlet 44 in the normal direction D1, and is discharged through the outlet tube section 24 and the outlet pipe 104 into the above-mentioned main sewer pipe connected to the outlet pipe 104.

[0060] In this embodiment, the valve element 55 of the backflow prevention means 50 normally opens the outflow port 44. Under normal circumstances, wastewater does not flow in the reverse flow direction D2, and an opening force is applied to the valve element 55 by the repulsion between the valve element-side magnetic body 71 and the main body-side magnetic body 72 of the opening force applying mechanism 57. This opening force is typically greater than the weight of the valve element 55. Therefore, under normal circumstances, the opening force is greater than the weight of the valve element 55. Therefore, under normal circumstances, the valve element 55 opens the outflow port 44 due to the opening force applied by the opening force applying mechanism 57. Under normal circumstances, when wastewater does not flow through the outflow port 44, the valve element 55 is positioned in an inclined state, as shown in FIG. 2 . Specifically, the valve element 55 is also positioned in an inclined state with respect to the communication port 60. In this embodiment, when wastewater normally flows in the normal direction D1, a large amount of wastewater may hit the valve element 55 and push the valve element 55 toward the normal direction D1. As a result, as shown in Fig. 4, the valve body 55 rotates via the hinge 64, increasing the opening area between the outlet 44 and the valve body 55 and allowing more wastewater to flow. When the valve body 55 is hit by the wastewater flowing in the normal direction D1, it can rotate up to a position extending horizontally as shown in Fig. 4 (for example, a position parallel to the pipe axis of the outflow tubular portion 24).

[0061] For example, if the main sewer pipe connected to the outflow conduit 104 breaks or if a large amount of wastewater flows into the main sewer pipe all at once, wastewater may backflow from the main sewer pipe toward the catch basin 10. During such backflow, the wastewater flows in a reverse flow direction D2 toward the outlet 44, as shown in FIG. 3 . At this time, the valve element 55, which opens the outlet 44, is pushed by the backflowing wastewater, exerting backflow pressure on the valve element 55. This backflow pressure increases as the amount of backflowing wastewater increases or the flow rate of the wastewater increases. When the opening force on the valve element 55 becomes less than the backflow pressure plus the weight of the valve element 55, the valve element 55 rotates about the hinge 64 and closes the communication port 60 formed in the backflow prevention body 51. The valve element 55 closes the outlet 44 by closing the communication port 60. As a result, when backflow occurs, the outlet 44 is closed and the backflowing wastewater is blocked by the valve body 55, making it difficult for the wastewater to flow into the main body 11 of the catch basin 10.

[0062] In this embodiment, as the amount of wastewater flowing back decreases, the backflow pressure applied to the valve element 55 decreases. When the opening force for the valve element 55 becomes equal to or greater than the backflow pressure plus the weight of the valve element 55, the valve element 55 rotates about the hinge 64 as an axis, as shown in Fig. 2, to open the communication port 60. By opening the communication port 60, the valve element 55 opens the outflow port 44.

[0063] As described above, in this embodiment, as shown in FIG. 2 , the catch basin 10 includes a main body 11 having a tubular main body portion 15 with an outlet 44, which is an example of a drain port through which wastewater passes, formed therein, and a backflow prevention mechanism 50 capable of closing the outlet 44 when wastewater passing through the outlet 44 backflows. The backflow prevention mechanism 50 includes a valve element 55 that opens and closes the outlet 44, and an opening force applying mechanism 57 that applies an opening force to the valve element 55 in a direction to open the outlet 44, at least during periods other than backflow, in which wastewater passing through the outlet 44 backflows. As shown in FIG. 3 , the valve element 55 is configured to close the outlet 44 during backflow by applying a backflow pressure, which is the pressure of wastewater when the wastewater passing through the outlet 44 backflows. As a result, as shown in FIG. 2 , during normal times other than backflow, the opening force applied to the valve element 55 by the opening force applying mechanism 57 keeps the outlet 44 open from the valve element 55. This allows wastewater to flow more easily through the outlet 44 during normal times. 3, during backflow, backflow pressure is applied to the valve element 55, causing the valve element 55 to close the outlet 44. This makes it difficult for the backflowing wastewater to flow through the outlet 44 during backflow.

[0064] In this embodiment, the valve body 55 of the backflow prevention means 50 opens and closes the outlet 44 through which the wastewater passes when it flows out of the main body 11. This makes it difficult for the backflowing wastewater to flow into the tubular main body portion 15 of the main body 11 through the outlet 44 during backflow.

[0065] In this embodiment, the valve element 55 is configured to close the outflow port 44 when the sum of the backflow pressure and the weight of the valve element 55 is greater than the opening force. In this way, when the amount of backflowing wastewater increases and the backflow pressure increases, and the sum of the backflow pressure and the weight of the valve element 55 becomes greater than the opening force, the valve element 55 can close the outflow port 44. Therefore, it is possible to make it more difficult for the backflowing wastewater to pass through the outflow port 44 depending on the magnitude of the backflow pressure.

[0066] 2, in this embodiment, the opening force imparting mechanism 57 has a valve-element-side magnetic body 71 provided on the valve element 55 and a body-side magnetic body 72 fixed to the main body 11. The valve-element-side magnetic body 71 and the body-side magnetic body 72 generate an opening force by the magnetic force that repels each other. In this way, by using the repulsive magnetic force between the valve-element-side magnetic body 71 and the body-side magnetic body 72, an opening force can be generated on the valve element 55. Therefore, the valve element 55 can be opened from the outlet 44 under normal circumstances by using the magnetic force.

[0067] In this embodiment, the backflow prevention means 50 includes a backflow prevention body 51 that is attached to the outlet 44 and has a communication port 60 that communicates with the outlet 44. The valve element 55 is configured to open and close the outlet 44 by opening and closing the communication port 60. The body-side magnetic body 72 is provided in a portion of the backflow prevention body 51 that faces the valve element-side magnetic body 71 when the valve element 55 closes the communication port 60. The valve element-side magnetic body 71 and the body-side magnetic body 72 generate an opening force due to their mutually repulsive magnetic forces. In this way, by arranging the body-side magnetic body 72 in a portion of the backflow prevention body 51 that faces the valve element-side magnetic body 71, an opening force can be generated on the valve element 55 using the repulsive magnetic force between the valve element-side magnetic body 71 and the body-side magnetic body 72.

[0068] In this embodiment, the communication port 60 is inclined downwardly away from the outlet 44. As a result, as shown in Fig. 3, when the valve element 55 closes the communication port 60, the valve element 55 can close the communication port 60 while inclined along the inclination of the communication port 60. This makes it easier for the valve element 55 to close the communication port 60 during backflow.

[0069] In this embodiment, the main body 11 has an outflow tubular portion 24, which is an example of a drain tubular portion, connected to the outlet 44 on the outside of the main body tubular portion 15. A backflow prevention main body 51 is fitted into the outflow tubular portion 24. The backflow prevention means 50 is provided between the backflow prevention main body 51 and the outflow tubular portion 24 and has an annular elastic body 53 that follows the circumferential direction of the backflow prevention main body 51. This annular elastic body 53 can improve the sealing performance between the backflow prevention main body 51 and the outflow tubular portion 24. This makes it less likely that drainage will leak between the backflow prevention main body 51 and the outflow tubular portion 24.

[0070] 6, the elastic body 53 has an upper portion 53a and a lower portion 53b that is disposed below the upper portion 53a and extends further in the axial direction of the outlet 44 (here, normal direction D1) than the upper portion 53a. For example, in the catch basin 10, wastewater tends to flow toward the lower portion of the backflow prevention main body 51. Therefore, by extending the lower portion 53b of the elastic body 53 in the axial direction of the outlet 44 (here, normal direction D1), it is possible to further improve the sealing performance between the lower portion of the backflow prevention main body 51, through which wastewater tends to flow, and the outlet tubular portion 24.

[0071] In this embodiment, as shown in Fig. 4, the valve element 55 is disposed within the outflow tubular portion 24. When the outflow port 44 is open, the valve element 55 is curved along the inner circumferential surface of the outflow tubular portion 24. Because the valve element 55 is curved along the inner circumferential surface of the outflow tubular portion 24 in this manner, it is possible to reduce the likelihood of interference with the outflow tubular portion 24 when opening and closing the outflow port 44. Furthermore, because the valve element 55 opens the outflow port 44 while curved along the inner circumferential surface of the outflow tubular portion 24, the outflow port 44 can be opened more widely. Therefore, more wastewater can flow through the outflow port 44 under normal circumstances.

[0072] Second Embodiment Next, the catch basins 10A, 10B, and 10C according to the second to fourth embodiments will be described in order. In the second to fourth embodiments, the configuration of the backflow prevention means, other than the opening force imparting mechanism, is the same as that of the catch basin 10 according to the first embodiment, and therefore the description will be omitted as appropriate. In the second to fourth embodiments, the configuration of the catch basin 10 according to the first embodiment can be adopted as appropriate. For example, the elastic body 53 of the backflow prevention means 50 according to the first embodiment can be adopted in the second to fourth embodiments.

[0073] First, a catch basin 10A according to the second embodiment will be described. FIGS. 10 and 11 are cross-sectional views schematically illustrating the outlet tube portion 24 of the catch basin 10A according to the second embodiment. FIG. 10 illustrates a state in which the valve body 55 opens the outlet 44. FIG. 11 illustrates a state in which the valve body 55 closes the outlet 44. As shown in FIG. 11, the catch basin 10A includes a backflow prevention means 50A that can close the outlet 44 when wastewater passing through the outlet 44 backflows. As shown in FIG. 10, the backflow prevention means 50A normally includes an opening force imparting mechanism 57A that imparts an opening force to the valve body 55. In the first embodiment, the opening force imparting mechanism 57 generates the opening force using repulsive magnetic forces. However, in the second embodiment, the opening force imparting mechanism 57A generates the opening force imparted to the valve body 55 using attractive magnetic forces.

[0074] In this embodiment, the opening force imparting mechanism 57A has a valve-element-side magnetic body 71A and a main body-side magnetic body 72A. The valve-element-side magnetic body 71A and the main body-side magnetic body 72A generate magnetic forces and are formed, for example, by magnets. Here, the valve-element-side magnetic body 71A and the main body-side magnetic body 72A are arranged so as to generate an attractive force between them. This attractive force serves as an opening force that normally opens the valve element 55 from the outlet 44.

[0075] In this embodiment, the valve-element-side magnetic body 71A is provided on the valve element 55. The valve-element-side magnetic body 71A is provided on the upper part of the surface of the valve element 55 opposite to the backflow prevention main body 51. Although one valve-element-side magnetic body 71A is shown in FIG. 10, the number of valve-element-side magnetic bodies 71A may be two, as with the valve-element-side magnetic body 71 according to the first embodiment, or may be three or more.

[0076] The main body side magnetic body 72A is fixed to the main body 11 of the catch basin 10A. In this embodiment, the main body side magnetic body 72A is provided on the inner circumferential surface of the outflow tube portion 24 of the main body 11. More specifically, the main body side magnetic body 72A is provided on a portion of the inner circumferential surface of the outflow tube portion 24 that faces the valve body side magnetic body 71A when the valve body 55 opens the outflow port 44. The main body side magnetic body 72A is paired with the valve body side magnetic body 71A, and the number of the main body side magnetic bodies 72A is the same as the number of the valve body side magnetic bodies 71A.

[0077] As described above, the valve-body-side magnetic body 71A and the main body-side magnetic body 72A are arranged so that they attract each other. Here, for example, if the surface of the valve-body-side magnetic body 71A facing the main body-side magnetic body 72A is an S pole, the surface of the main body-side magnetic body 72A facing the valve-body-side magnetic body 71A will be an N pole. Also, for example, if the surface of the valve-body-side magnetic body 71A facing the main body-side magnetic body 72A is an N pole, the surface of the main body-side magnetic body 72A facing the valve-body-side magnetic body 71A will be an S pole.

[0078] In this embodiment, when the valve element 55 opens the outlet 44, the valve element-side magnetic body 71A and the main body-side magnetic body 72A may stick together. If the valve element-side magnetic body 71A and the main body-side magnetic body 72A stick together, the valve element 55 may have difficulty closing the outlet 44, even when backflow pressure caused by backflow of wastewater is applied to the valve element 55. Therefore, in this embodiment, as shown in FIG. 10 , a restricting member 73 is provided between the valve element 55 and the inner circumferential surface of the outlet tubular portion 24 when the valve element 55 opens the outlet 44. The restricting member 73 is a member for preventing the valve element-side magnetic body 71A and the main body-side magnetic body 72A from sticking together when the valve element 55 opens the outlet 44. The restricting member 73 is configured to come into contact with the valve element 55 when the valve element 55 rotates beyond a predetermined rotation angle and restrict further rotation of the valve element 55. For example, the restricting member 73 is provided around the hinge 64. The restricting member 73 is provided closer to the hinge 64 than the valve-body-side magnetic body 71A. In this embodiment, the restricting member 73 is attached to the inner circumferential surface of the outflow cylindrical portion 24, but it may also be attached to the valve body 55.

[0079] In this embodiment, as shown in Fig. 10, the attractive force between the valve-element-side magnetic body 71A and the main body-side magnetic body 72A normally serves as an opening force. This opening force is greater than the weight of the valve element 55. Therefore, normally, the valve element 55 opens the outflow port 44. At this time, since the restricting member 73 is interposed between the inner circumferential surface of the outflow cylindrical portion 24 and the valve element 55, the valve element-side magnetic body 71A and the main body-side magnetic body 72A do not easily stick together.

[0080] As shown in FIG. 11 , during backflow, wastewater flowing in the backflow direction D2 presses on the valve disc 55, applying backflow pressure to the valve disc 55. When the opening force on the valve disc 55 becomes less than the backflow pressure plus the weight of the valve disc 55, the valve disc 55 rotates about the hinge 64 to close the outlet 44. Therefore, the backflowing wastewater is blocked by the valve disc 55, making it difficult for the backflowing wastewater to flow into the main body 11 of the catch basin 10. Even in this embodiment, as the amount of backflowing wastewater decreases, the backflow pressure applied to the valve disc 55 decreases. When the opening force on the valve disc 55 becomes greater than or equal to the backflow pressure plus the weight of the valve disc 55, the valve disc 55 rotates about the hinge 64 to open the outlet 44, as shown in FIG. 10 .

[0081] In this embodiment, too, since the valve body 55 normally opens the outlet 44, it is possible to facilitate the flow of wastewater through the outlet 44. Furthermore, since the valve body 55 closes the outlet 44 during backflow, it is possible to make it difficult for the backflowing wastewater to flow through the outlet 44.

[0082] <Third embodiment> Next, a catch basin 10B according to a third embodiment will be described. FIGS. 12 and 13 are cross-sectional views schematically illustrating the outlet tube portion 24 of the catch basin 10B according to the third embodiment. FIG. 12 illustrates a state in which the valve body 55 opens the outlet 44. FIG. 13 illustrates a state in which the valve body 55 closes the outlet 44. As shown in FIG. 13, the catch basin 10B includes a backflow prevention means 50B that can close the outlet 44 when wastewater passing through the outlet 44 backflows. As shown in FIG. 12, the backflow prevention means 50B normally includes an opening force applying mechanism 57B that applies an opening force to the valve body 55. In this embodiment, the opening force applying mechanism 57B uses elastic force to generate the opening force to be applied to the valve body 55.

[0083] In this embodiment, the opening force imparting mechanism 57B has an elasticity generating body 71B. The elasticity generating body 71B is formed from a member having a predetermined elastic force. There are no particular limitations on the material from which the elasticity generating body 71B is formed, as long as it can generate the predetermined elastic force. In this embodiment, the elasticity generating body 71B is formed from rubber (for example, synthetic rubber such as EPDM). However, the elasticity generating body 71B may also be formed from a porous material such as a sponge, or may also be formed from a spring.

[0084] In this embodiment, the elasticity generating body 71B is disposed between the valve body 55 and the outlet 44. Here, the elasticity generating body 71B is disposed between the valve body 55 and the surface of the backflow prevention body 51 facing the valve body 55. The elasticity generating body 71B is provided on the backflow prevention body 51, but may also be provided on the valve body 55. In this embodiment, the elasticity generating body 71B applies an elastic force from the outlet 44 toward the valve body 55. The elastic force applied to the valve body 55 becomes an opening force.

[0085] In this embodiment, as shown in Fig. 12, under normal circumstances, the elasticity generating body 71B applies an elastic force to the valve body 55, pushing the valve body 55 in the normal direction D1. This elastic force of the elasticity generating body 71B serves as an opening force. This opening force is greater than the weight of the valve body 55. Therefore, under normal circumstances, the valve body 55 opens the outlet 44.

[0086] As shown in FIG. 13 , during backflow, the wastewater flowing in the backflow direction D2 presses on the valve disc 55, applying backflow pressure to the valve disc 55. When the opening force on the valve disc 55 becomes less than the backflow pressure plus the weight of the valve disc 55, the valve disc 55 rotates about the hinge 64, causing the elasticity generating body 71B to be crushed by the valve disc 55. As the elasticity generating body 71B is crushed in this manner, the valve disc 55 closes the outlet 44. Therefore, the backflowing wastewater is blocked by the valve disc 55, making it difficult for the wastewater to flow into the main body 11 of the catch basin 10. Furthermore, even in this embodiment, as the amount of backflowing wastewater decreases, the backflow pressure applied to the valve disc 55 decreases, and the elasticity generating body 71B gradually presses the valve disc 55. Then, when the opening force for the valve body 55 becomes equal to or greater than the backflow pressure plus the weight of the valve body 55, as shown in Figure 12, the valve body 55 is pushed by the elasticity generating body 71B, causing it to rotate around the hinge 64 and open the outlet 44.

[0087] In this embodiment, too, since the valve body 55 normally opens the outlet 44, it is possible to facilitate the flow of wastewater through the outlet 44. Furthermore, since the valve body 55 closes the outlet 44 during backflow, it is possible to make it difficult for the backflowing wastewater to flow through the outlet 44.

[0088] <Fourth embodiment> Next, a catch basin 10C according to a fourth embodiment will be described. FIGS. 14 and 15 are cross-sectional views schematically illustrating the outlet tube portion 24 of the catch basin 10C according to the fourth embodiment. FIG. 14 illustrates a state in which the valve body 55 opens the outlet 44. FIG. 15 illustrates a state in which the valve body 55 closes the outlet 44. As shown in FIG. 15, the catch basin 10C includes a backflow prevention means 50C that can close the outlet 44 when wastewater passing through the outlet 44 backflows. As shown in FIG. 14, the backflow prevention means 50C includes an opening force imparting mechanism 57C that normally imparts an opening force to the valve body 55. In this embodiment, the opening force imparting mechanism 57C generates an opening force to be imparted to the valve body 55 using a support force that supports the valve body 55 in a state in which it is opened from the outlet 44.

[0089] In this embodiment, the opening force imparting mechanism 57C has a pair of support pieces 71C and a recess 72C. Here, the pair of support pieces 71C are provided on the surface of the backflow prevention main body 51 facing the valve body 55. The recess 72C is provided on the surface of the valve body 55 facing the backflow prevention main body 51. The recess 72C is configured to be able to fit into the pair of support pieces 71C, and is positioned opposite the pair of support pieces 71C.

[0090] The pair of support pieces 71C face each other and are configured to bend in a direction narrowing toward each other. Although not shown, the tip ends of the pair of support pieces 71C may be provided with protrusions that protrude in directions away from each other. The recesses 72C fit into the pair of support pieces 71C when the pair of support pieces 71C bend in a direction narrowing toward each other.

[0091] In this embodiment, as shown in FIG. 14 , under normal circumstances, the valve element 55 rests on at least one of a pair of support pieces 71C provided on the backflow prevention main body 51. At this time, the pair of support pieces 71C support the valve element 55 and apply a supporting force to the valve element 55. At this time, the tips of the pair of support pieces 71C may be slightly recessed into the recess 72C of the valve element 55. As such, under normal circumstances, the pair of support pieces 71C apply a supporting force to the valve element 55 and support the valve element 55. This supporting force serves as an opening force. This opening force is greater than the weight of the valve element 55. Therefore, under normal circumstances, the valve element 55 opens the outflow port 44. Note that even in this embodiment, when wastewater flows in the normal direction D1 under normal circumstances, the valve element 55 is pushed in the normal direction D1 by the wastewater, causing it to rotate about the hinge 64, and the opening area between the valve element 55 and the outflow port 44 becomes larger. Therefore, more wastewater can be discharged through the outlet 44 under normal circumstances.

[0092] As shown in Figure 15, during backflow, wastewater flowing in the backflow direction D2 presses on the valve element 55, applying backflow pressure to the valve element 55. When the opening force on the valve element 55 becomes less than the backflow pressure plus the weight of the valve element 55, the valve element 55 rotates about the hinge 64, causing the pair of support pieces 71C to bend in a direction narrowing toward each other and fit into the recesses 72C. In this way, the pair of support pieces 71C fit into the recesses 72C, causing the valve element 55 to close the outflow port 44. Therefore, the backflowing wastewater is blocked by the valve element 55, making it difficult for the wastewater to flow into the main body 11 of the catch basin 10.

[0093] In this embodiment, even if the wastewater no longer flows backward, the pair of support pieces 71C may remain fitted in the recessed portion 72C. Therefore, even if the wastewater no longer flows backward, the outlet 44 may remain closed by the valve body 55. Therefore, in this embodiment, after the backflow of the wastewater has stopped, the worker may remove the pair of support pieces 71C from the recessed portion 72C and release the valve body 55 from the outlet 44.

[0094] In this embodiment, too, since the valve body 55 normally opens the outlet 44, it is possible to facilitate the flow of wastewater through the outlet 44. Furthermore, since the valve body 55 closes the outlet 44 during backflow, it is possible to make it difficult for the backflowing wastewater to flow through the outlet 44.

[0095] In each of the above embodiments, the catch basins 10, 10A, 10B, and 10C have three inlets through which wastewater flows: the first inlet 41, the second inlet 42, and the third inlet 43. However, the number of inlets is not particularly limited and may be one, two, or four or more. Any one or two of the first inlet 41, the second inlet 42, and the third inlet 43 may be omitted.

[0096] In each of the above embodiments, the outlet 44 is an example of a drain port through which wastewater passes in the present invention. However, the drain port is not limited to the outlet 44. For example, the drain port may be any of the first inlet 41, the second inlet 42, and the third inlet 43 through which wastewater passes when it flows into the main body 11. In this case, the backflow prevention means 50 may be capable of closing any of the first inlet 41, the second inlet 42, and the third inlet 43, and the valve body 55 may be capable of opening and closing any of the first inlet 41, the second inlet 42, and the third inlet 43.

[0097] The catch basins 10, 10A, 10B, and 10C in the above-described embodiments are examples of piping members according to the present invention. However, the piping members are not limited to the catch basins 10, 10A, 10B, and 10C. The piping members may be, for example, pipe joints or manholes. [Explanation of symbols]

[0098] 10, 10A, 10B, 10C Drainage manhole (piping components) 11 Main unit 15 Main body cylinder 24 Outflow pipe part (drain pipe part) 44 Outlet (drain) 50, 50A, 50B, 50C Backflow prevention means 51 Backflow prevention body 53 Elastic Body 53a Upper part 53b Lower part 55 Valve body 57 Opening force applying mechanism 60 Connecting port 71, 71A Valve body side magnetic material 72, 72A Main body side magnetic body

Claims

1. a main body having a main body tubular portion formed with a drainage port through which drainage passes; a backflow prevention means capable of closing the drain outlet when wastewater passing through the drain outlet flows back; Equipped with The backflow prevention means is a valve body that opens and closes the drain outlet; an opening force applying mechanism that applies an opening force to the valve body in a direction that opens the drain outlet at least when the drained water passing through the drain outlet is not flowing backward; and A piping component configured such that the valve body closes the drain outlet when backflow pressure, which is the pressure of the drainage when the drainage passing through the drain outlet flows backward, is applied during the backflow.

2. The piping member according to claim 1 , wherein the drain port is an outlet through which wastewater passes when it flows out of the main body.

3. The piping member according to claim 1 , wherein the valve body is configured to close the drain port when the sum of the backflow pressure and the weight of the valve body is greater than the opening force.

4. The opening force imparting mechanism includes: a valve element-side magnetic body provided on the valve element; a main body side magnetic body fixed to the main body; and 4. The piping member according to claim 1, wherein the valve-side magnetic body and the main body-side magnetic body generate the opening force by magnetic forces that repel or attract each other.

5. the backflow prevention means is attached to the drain outlet and has a backflow prevention body formed with a communication port that communicates with the drain outlet, The valve body is configured to open and close the drain outlet by opening and closing the communication port, the main body-side magnetic body is provided in a portion of the backflow prevention main body that faces the valve body-side magnetic body when the valve body closes the communication port, The piping member according to claim 4 , wherein the valve-side magnetic body and the main body-side magnetic body generate the opening force by mutually repulsive magnetic forces.

6. The piping member according to claim 5 , wherein the communication opening is inclined downwardly away from the drain opening.

7. The main body has a drain tube portion connected to the drain outlet on the outside of the main body tube portion, the backflow prevention means is attached to the drain outlet and has a backflow prevention body formed with a communication port that communicates with the drain outlet, The valve body is configured to open and close the drain outlet by opening and closing the communication port, The backflow prevention body is fitted into the drain tube portion, 2. The piping member according to claim 1, wherein the backflow prevention means is provided between the backflow prevention body and the drain tube portion and has an annular elastic body that follows the circumferential direction of the backflow prevention body.

8. The elastic body is The upper part and a lower portion disposed below the upper portion and extending further in the axial direction of the drain outlet than the upper portion; The piping member according to claim 7, comprising:

9. The main body has a drain tube portion connected to the drain outlet on the outside of the main body tube portion, The valve body is disposed in the drain tube portion, The piping member according to claim 1 , wherein the valve body is curved along an inner peripheral surface of the drain tube portion when the drain outlet is open.

10. In a piping member having a main body formed with a drain port through which drainage passes, a backflow prevention valve capable of closing the drain port when drainage passing through the drain port backflows, a valve body that opens and closes the drain outlet; an opening force applying mechanism that applies an opening force to the valve body in a direction that opens the drain outlet at least when the drained water passing through the drain outlet is not flowing backward; Equipped with The valve body is a backflow prevention valve configured to close the drain outlet when backflow occurs by applying backflow pressure, which is the pressure of the drainage when the drainage passing through the drain outlet flows backward.

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