Backflow prevention joint

Abstract

To provide a backflow prevention fitting capable of being installed between the upstream drain pipe and the downstream drain pipe, which is configured so that a check valve (valve body) reliably closes even against backflow water that flows upward from below the check valve (valve body).MEANS FOR SOLVING THE PROBLEM: A disclosed backflow prevention fitting includes: an inlet that extends horizontally; an outlet that extends horizontally or vertically; a body connecting the inlet and the outlet; a valve pipe that communicates with the inlet and projects into the body; a valve seat that is formed at the open end of the valve pipe inclining toward the inlet from the top to the bottom; and a valve body rotatably supported at the upper part of the valve pipe and at a position offset toward the inlet port from the open end of the valve pipe.SELECTED DRAWING: Figure 7a

Description

Technical Field

[0001] The present invention relates to a backflow prevention joint that includes a valve pipe inside and a check valve (valve body) that opens and closes with respect to the valve pipe, and connects a horizontally extending drain pipe and a vertically extending drain pipe. In particular, the check valve (valve body) is rotatably supported at a position offset toward the inlet side from the upper part of the valve pipe and the opening end of the valve pipe. The present invention relates to a backflow prevention joint characterized by this.

Background Art

[0002] Generally, the drainage discharged from drainage facilities such as toilets, bathrooms, and kitchens in houses, etc., is collected in a drain pit installed on the residential land via drain pipes connected to each drainage facility, and the drainage collected in the drain pit flows out to the main sewer pipe via a public drain pit or a manhole.

[0003] Also, in order to prevent the intrusion of backflow water generated in downstream drainage facilities such as the main sewer pipe into the house, for example, as described in Japanese Patent Application Laid-Open No. 2020-153508 (Patent Document 1), a backflow prevention device attached to the inlet of a drain pit or the like is widely known.

[0004] On the other hand, in recent years, due to the occurrence of abnormal weather associated with global warming and the like, there have been many cases where a large amount of rainwater flows into the main sewer pipe in a short period of time. Therefore, in order to more effectively prevent the backflow of rainwater and the like, for example, as described in Japanese Patent Application Laid-Open No. 2021-169701 (Patent Document 2), a drain pit or a vertical pipe is provided between the upstream drain pipe and the downstream drain pipe having a height difference, and a backflow prevention device as described in Patent Document 1 is attached to the outlet of the upstream drain pipe on the upstream side. The number of such cases is also increasing.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] However, depending on the amount of rainwater and other factors generated, backflow water may flow in horizontally, directly colliding with the check valve of the backflow prevention device, or it may flow in upward from below the check valve, causing the liquid level to rise. Therefore, in the check valves (valve bodies) described in Patent Documents 1 and 2, which are suspended almost directly below (vertically) the point of rotation, the valve body moves in either the opening or closing direction depending on how the backflow water collides, resulting in an extremely unstable opening and closing operation.

[0007] In particular, when a backflow prevention device is connected between an upstream drain pipe and a downstream drain pipe with a difference in elevation, the backflow water does not flow horizontally so as to collide with the front of the check valve, but rather flows upward from below the check valve. As a result, with check valves (valve bodies) such as those described in Patent Documents 1 and 2, the backflow water flows around to the back side (upstream side) of the valve body before the front side (downstream side), and the valve body moves in the direction of opening to block the flow of backflow water, which is a problem.

[0008] Furthermore, if one attempts to install a backflow prevention device, such as the one described in Patent Document 1, at the connection point between an upstream drainage pipe and a downstream drainage pipe with a difference in elevation, it becomes necessary to install a drainage manhole or vertical pipe for the backflow prevention device at that location, resulting in a complex configuration and large-scale construction work.

[0009] Furthermore, when attempting to install drainage manholes or vertical pipes and attach backflow prevention devices as described in Patent Document 1, there is a problem in that the drainage manholes or vertical pipes must be made larger than the size determined by the drainage flow rate in order to secure space for the movement of the check valve. Moreover, since backflow prevention devices are generally installed near the wall surface of drainage manholes or vertical pipes, even if inspection openings are provided at the top of them, they cannot be easily accessed (see Figure 2 in Patent Document 2), which causes problems in maintenance and other operations.

[0010] Therefore, the present invention aims to provide a backflow suppression joint (backflow prevention device) that can reliably close the check valve (valve body) against backflow water that flows in horizontally, directly impacting the check valve (valve body), and against backflow water that flows in upward from below the check valve, causing the liquid level to rise. Furthermore, the present invention aims to provide a backflow suppression joint (backflow prevention device) that can be easily installed between an upstream drain pipe and a downstream drain pipe with a difference in elevation, without the need to install drain manholes or vertical pipes, and that can reliably close the check valve (valve body) against backflow water that flows upward from below the check valve (valve body). [Means for solving the problem]

[0011] The inventors of the present invention have diligently studied the piping layout and the structure of the check valve (valve body) when installing a backflow prevention joint (backflow prevention device) at the connection point between an upstream drain pipe and a downstream drain pipe. As a result, they have found that in a joint having an inlet open for connection to the upstream drain pipe and an outlet open for connection to the downstream drain pipe, if a valve pipe communicating with the inlet and a check valve (valve body) that opens and closes relative to the valve pipe are provided inside, and the check valve (valve body) is rotatably supported at a position above the valve pipe and offset toward the inlet side from the opening end of the valve pipe, it is possible to ensure sufficient space for the movement of the check valve (valve body) without unnecessarily increasing the size of the backflow prevention joint, and to operate the check valve (valve body) in a way that reliably closes against backflowing water, thus completing the present invention.

[0012] In other words, the present invention provides a backflow suppression joint comprising an inlet, an outlet, a body connecting the inlet and the outlet, a valve pipe communicating with the inlet and protruding into the body, a valve seat formed at the open end of the valve pipe which is inclined to approach the inlet from top to bottom, and a valve body rotatably supported at the upper part of the valve pipe and at a position offset toward the inlet side from the open end of the valve pipe. In this case, the inlet and outlet may extend horizontally, or the inlet may extend horizontally and the outlet may extend vertically.

[0013] In this invention, since the pivot point of the valve body is positioned above the valve tube and offset toward the inlet side from the open end (valve seat) of the valve tube, the trajectory of the lower end of the valve body, that is, the trajectory of the part of the valve body furthest from the pivot point, approaches the inlet and valve seat. As a result, without changing the opening and closing angle of the valve body, the range of motion of the valve body in the outlet region of the valve tube can be substantially narrowed, and the backflow suppression joint can be made more compact.

[0014] Furthermore, since the center of gravity of the valve body is located vertically below the pivot point of the valve body, if the pivot point of the valve body is positioned offset as described above, when the valve body is suspended, it will be positioned at an inclination such that the contact surface with the valve seat approaches the inlet side as it moves from the top to the bottom. For this reason, it is preferable that the center of gravity of the valve body be located downstream of the contact surface with the valve seat when the valve body is suspended.

[0015] In other words, in the present invention, when the outer diameter of the open end of the valve tube is D (mm) and the distance from the open end face of the valve tube to the pivot point of the valve body is L (mm), it is desirable that L / D is preferably 0.15 or more and 0.45 or less, and more preferably 0.20 or more and 0.40 or less.

[0016] If the L / D ratio is set to less than 0.15, the valve body cannot be tilted sufficiently so that the backflow water rising upward from the outlet first hits the downstream surface of the valve body. This makes the valve body more likely to move in the opening direction, and it becomes impossible to adequately block the flow of backflow water. Furthermore, it becomes impossible to narrow the range of motion of the valve body in the outlet region of the valve pipe to the extent that it contributes to the compactness of the backflow suppression joint. On the other hand, if the L / D ratio is set to more than 0.45, space must be secured for the movement of the support arm of the elongated valve body, resulting in the disadvantage of the joint body becoming unnecessarily large.

[0017] Furthermore, the valve body preferably has a circular shape so that it can make liquid-tight contact with the circular valve seat when viewed from the front, and preferably has a recess that is recessed from the downstream side to the upstream side when viewed from the side, such that the force (resistance) received from reverse flow drainage is large and the force (resistance) received from forward flow drainage is small.

[0018] As a result, the backflow suppression joint of the present invention can reliably close the valve body even when backflow water flows in horizontally, directly impacting the valve body, or when backflow water flows in upward from below the valve body, causing the liquid level to rise. Furthermore, even when the backflow suppression joint of the present invention is installed between an upstream drain pipe and a downstream drain pipe with a difference in height, backflow water rising upward from the outlet of the backflow suppression joint will impact the downstream surface of the valve body first, rather than the upstream surface, thus making the operation of closing the valve body with backflow water more reliable.

[0019] In the present invention, the inlet may be formed to have a first central axis extending horizontally, and the outlet may be formed to have a second central axis extending vertically. That is, the backflow suppression joint of the present invention may be configured to include an inlet having a first central axis extending horizontally, an outlet having a second central axis extending vertically, a body connecting the inlet and the outlet, a valve pipe communicating with the inlet and protruding into the body, a valve seat formed at the open end of the valve pipe which is inclined to approach the inlet from top to bottom, and a valve body rotatably supported at the upper part of the valve pipe and at a position offset toward the inlet side from the open end of the valve pipe.

[0020] In this case, the backflow prevention joint of the present invention can be easily installed between an upstream drain pipe and a downstream drain pipe that have a difference in height. Because of the difference in height, it can more effectively prevent backflow of wastewater and the rise of backflow water than conventional backflow prevention devices that are installed between upstream and downstream drain pipes that do not have a difference in height and are at approximately the same level. Furthermore, in the present invention, the pivot point of the valve body is positioned offset, so that a narrowed movable space for the valve body is secured in the outlet region of the valve pipe, and the valve body can be operated to reliably close to backflow water.

[0021] In this specification, "horizontal" does not mean only the horizontal direction in a strict sense, but is used to include a range that includes a degree of gradient provided when drainage is directed horizontally. Similarly, "vertical" does not mean only the vertical direction in a strict sense, but is used to include a range that includes a degree of error that occurs during the manufacturing and installation of joints.

[0022] In this invention, a valve pipe is provided that communicates with the inlet and protrudes into the body, so as to ensure that wastewater flowing horizontally from the inlet is reliably and smoothly deflected downward within the joint, and so as to allow the outlet to be positioned perpendicular to the inlet. The valve pipe only needs to be provided so that all or part of its circumferential direction protrudes into the body.

[0023] Also, the valve body holds a slightly open state during normal times, allowing a forward flow drainage to occur even when the drainage volume is small, thus preventing drainage blockage caused by foreign objects or the like. Therefore, the opening end of the valve pipe is inclined so as to approach the inlet as it goes from the upper part to the lower part.

[0024] As described above, when the backflow prevention joint of the present invention is provided with an inlet opening horizontally and an outlet opening vertically, it can be easily connected directly or via an elbow pipe or the like between the upstream drain pipe and the downstream drain pipe having a height difference. Moreover, since the backflow prevention joint of the present invention includes a valve body that functions as a check valve and a valve seat portion of the valve pipe, if it is connected between the upstream drain pipe and the downstream drain pipe, a function as a backflow prevention device can also be obtained simultaneously.

[0025] Also, when the backflow prevention joint is provided with an inlet and an outlet arranged to be orthogonal, it further includes an inspection port having a third central axis extending from the body portion and extending obliquely upward away from the inlet, and a lid portion detachably attached to the inspection port, and it is preferable that the valve body is rotatably supported by the lid portion.

[0026] Furthermore, if the backflow prevention joint of the present invention includes an inspection port extending from the body portion in the middle of the joint body and extending obliquely upward away from the inlet, it is possible to secure a movable space for the check valve without unnecessarily increasing the size of the backflow prevention joint, and since it is possible to easily access the valve body, valve seat portion, etc. through the inspection port, maintenance such as inspection and cleaning can be easily carried out.

[0027] Also, by attaching the valve body to the lid portion, when the lid portion is removed, the valve body can be removed together, and the inside of the joint after removing the valve body can be made substantially hollow, so that maintenance such as inspection and cleaning inside the joint becomes even easier.

[0028] In the present invention, the lid is preferably composed of a cap portion that is not rotatably attached to the inspection opening in the circumferential direction, and a lid body that is rotatably attached to the inspection opening in the circumferential direction on the cap portion, and the valve body is preferably supported by the cap portion.

[0029] Furthermore, when the lid is composed of a lid body and a cap portion as described above, it is preferable that a first engaging portion is provided on the inner circumferential surface of the inspection opening to fix the cap portion so that it cannot rotate circumferentially relative to the inspection opening, and that a second engaging portion is provided on the cap portion to engage with the first engaging portion, so that the valve body can be easily set in the predetermined position.

[0030] Furthermore, if the valve body is attached to the cover, and the cover becomes detached from the inspection port for any reason, the valve body will also come off, making it impossible to prevent backflow of wastewater. For this reason, in the present invention, it is preferable to have a locking mechanism to prevent the cover from becoming detached from the inspection port due to an increase in the pressure of water or air inside the joint. The locking mechanism can be, for example, a bayonet mechanism that allows for arbitrary selection of engagement and disengagement between the cover and the inspection port by rotating the cover circumferentially relative to the inspection port.

[0031] Furthermore, using a bayonet mechanism as a locking mechanism for the lid not only prevents the lid from unintentionally detaching, but also allows the cap to be secured by being sandwiched between the lid body and the inspection opening. This ensures that the valve body supported by the cap is precisely set in its designated position without any looseness.

[0032] In this invention, from the viewpoint of preventing the joint body from becoming unnecessarily large and ensuring space for the valve body to move downstream, it is preferable that the diameter of the inspection port is the same as the diameter of the outlet. Furthermore, the diameter of the outlet may be the same as the diameter of the inlet, but it is preferable that it be larger than the diameter of the inlet. Therefore, when the diameter of the outlet is the same as the diameter of the inspection port, the diameter of the inspection port will also be larger than the diameter of the inlet.

[0033] In this specification, "identical" bore diameter does not mean that the bore diameters are exactly the same, but rather includes a range in which the inner diameter of one and the outer diameter of the other, or the outer diameter of one and the inner diameter of the other, are approximately the same, including manufacturing tolerances. [Effects of the Invention]

[0034] The present invention provides a backflow suppression joint comprising an inlet, an outlet, a body connecting the inlet and the outlet, a valve tube communicating with the inlet and protruding into the body, a valve seat formed at the open end of the valve tube which slopes toward the inlet from top to bottom, and a valve body rotatably supported at the upper part of the valve tube and offset toward the inlet side from the open end of the valve tube. In this case, the inlet and outlet may extend horizontally, or the inlet may extend horizontally and the outlet may extend vertically.

[0035] In particular, in this invention, when the outer diameter of the open end of the valve tube is D (mm) and the distance from the open end face of the valve tube to the pivot point of the valve body is L (mm), it is desirable that L / D is preferably 0.15 or more and 0.45 or less, and more preferably 0.20 or more and 0.40 or less. Furthermore, it is preferable that the center of gravity of the valve body is located downstream of the contact surface that contacts the valve seat portion of the valve body when the valve body is suspended.

[0036] According to the backflow suppression joint of the present invention, since the pivot point of the valve body is positioned above the valve pipe and offset toward the inlet side from the open end (valve seat) of the valve pipe, the trajectory of the lower end of the valve body, that is, the trajectory of the part of the valve body furthest from the pivot point, approaches the inlet and the valve seat. As a result, without changing the opening and closing angle of the valve body, the range of motion of the valve body in the outlet region of the valve pipe can be substantially narrowed, and the backflow suppression joint can be made more compact.

[0037] Furthermore, since the center of gravity of the valve body is located vertically below the fulcrum of the valve body, if the fulcrum of the valve body is positioned offset as described above, when the valve body is suspended, the valve body is positioned at an inclination such that the contact surface with the valve seat approaches the inlet side from top to bottom. Therefore, in the present invention, the valve body can be reliably closed not only by backflow water flowing in horizontally so as to collide with the valve body from the front, but also by backflow water flowing in upward from below the valve body so as to raise the liquid level. In addition, even when the backflow suppression joint of the present invention is installed between an upstream drain pipe and a downstream drain pipe with a difference in height, backflow water rising upward from the outlet of the backflow suppression joint will collide with the downstream surface of the valve body first, rather than the upstream surface, thus making the operation of closing the valve body with backflow water more reliable.

[0038] In the backflow prevention joint of the present invention, when an inlet opening horizontally and an outlet opening vertically are provided, it can be easily connected directly or via an elbow pipe or the like between an upstream drain pipe and a downstream drain pipe having a difference in height. Moreover, since the backflow prevention joint of the present invention is equipped with a valve body that functions as a check valve and a valve seat portion of a valve pipe, when connected between an upstream drain pipe and a downstream drain pipe, it also functions as a backflow prevention device.

[0039] Thus, the backflow prevention joint of the present invention can be easily installed between upstream and downstream drain pipes that have a difference in elevation. Therefore, because there is a difference in elevation, it can more effectively prevent backflow of wastewater and the rise of backflow water than conventional backflow prevention devices that are installed between upstream and downstream drain pipes that do not have a difference in elevation and are at approximately the same level. Furthermore, in the present invention, the pivot point of the valve body is offset, so that a narrowed movable space for the valve body is secured in the outlet region of the valve pipe, and the valve body can be operated to reliably close to the backflow water.

[0040] Furthermore, in a backflow prevention joint equipped with an inlet and outlet arranged perpendicularly to each other, if an inspection port is provided in the middle of the joint body that extends upward diagonally from the body and away from the inlet, it is possible to secure the movable space of the check valve without unnecessarily increasing the size of the backflow prevention joint, and the valve body and valve seat can be easily accessed through the inspection port, making maintenance and other processes easier. [Brief explanation of the drawing]

[0041] [Figure 1] This is a perspective view of a backflow prevention joint according to one embodiment of the present invention, as seen from the inspection port side. [Figure 2] Figure 1 is a perspective view of the backflow prevention joint shown from the inlet side. [Figure 3] Figures 1 and 2 are side views of the backflow suppression joint. [Figure 4] Figures 1 and 2 are front views of the backflow suppression joint. [Figure 5] Figures 1 and 2 show the rear view of the backflow suppression joint. [Figure 6] Figures 1 and 2 are plan views of the backflow prevention joint. [Figure 7a] Figure 6 is a cross-sectional view of the backflow suppression joint shown, taken at section AA. [Figure 7b] Figure 7a is a cross-sectional view of another application example of the backflow suppression joint shown. [Figure 7c] Figure 7a is a cross-sectional view of another application example of the backflow suppression joint shown. [Figure 7d] Figure 7a is a cross-sectional view of another application example of the backflow suppression joint shown. [Figure 8] This is a perspective view from above of the cover and valve body of a backflow suppression joint according to the first embodiment of the present invention. [Figure 9] Figure 8 is a perspective view of the lid and valve body from below. [Figure 10] Figures 8 and 9 are front views of the lid and valve body. [Figure 11] Figures 8 and 9 are side views of the lid and valve body. [Figure 12] Figures 8 and 9 show exploded views of the lid and valve body. [Modes for carrying out the invention]

[0042] A backflow suppression joint according to one embodiment of the present invention will be described in detail below with reference to the drawings. It should be noted that the present invention is not limited to the embodiments shown below, and various modifications are possible without departing from the technical spirit of the present invention.

[0043] Figure 1 shows a perspective view of the backflow suppression joint 1 according to one embodiment of the present invention, viewed from the inspection port 7 side. Figure 2 shows a perspective view of the backflow suppression joint 1 shown in Figure 1, viewed from the inlet 2 side. Figure 3 shows a side view of the backflow suppression joint 1 shown in Figure 1. Figure 4 shows a front view of the backflow suppression joint 1 shown in Figure 1. Figure 5 shows a rear view of the backflow suppression joint 1 shown in Figure 1. Figure 6 shows a plan view of the backflow suppression joint 1 shown in Figure 1. Figure 7a shows a cross-sectional view of the backflow suppression joint 1 shown in Figure 6, cut along section AA.

[0044] As shown in Figures 1-6 and 7a, the backflow suppression joint 1 of this embodiment comprises a joint body 10 consisting of an inlet 2, an outlet 3, a body 4 connecting the inlet 2 and the outlet 3, and an inspection port 7 provided in the body 4, and a cover 8 that can be detachably attached to the inspection port 7. Furthermore, a valve pipe 5 is provided in the body 4 so as to communicate with the inlet 2 and protrude into the interior of the body 4, a valve seat 50 is formed at the open end of the valve pipe 5, and a valve body 6 is supported inside the body 4 so as to be able to open and close relative to the valve seat 50. The backflow suppression joint 1 according to one embodiment of the present invention will be described in detail below, divided into the joint body 10, the cover 8, and the valve body 6.

[0045] <Fitting body> In this embodiment, the joint body 10 includes an inlet 2 that opens horizontally and has a first central axis a extending horizontally, and an outlet 3 that opens vertically and has a second central axis b extending vertically. In this embodiment, the inlet 2 has a socket shape, and the outlet 3 has a spigot shape. Therefore, a socket step portion 20 is formed inside the inlet 2, which functions as a stopper when the tip of the connected drain pipe abuts against it. In this embodiment, the inlet 2 has a socket shape and the outlet 3 has a spigot shape, but the shapes of the inlet 2 and outlet 3 are not limited to this combination, and either may have a socket shape or a spigot shape. Although not shown in the figures, in this embodiment, the joint body may also include an inlet that opens horizontally and extends horizontally, and an outlet that opens vertically and extends vertically.

[0046] As described above, the backflow prevention joint 1 of this embodiment is equipped with an inlet 2 that opens horizontally and an outlet 3 that opens vertically, so it can be easily connected between an upstream drain pipe and a downstream drain pipe (not shown) that have a difference in elevation. For example, if the upstream drain pipe extends horizontally and the downstream drain pipe extends vertically, the backflow prevention joint 1 can be directly connected between them. If both the upstream and downstream drain pipes extend horizontally while having a difference in elevation, the backflow prevention joint 1 can be connected between them by attaching an elbow pipe or the like to the outlet 3.

[0047] Furthermore, since the backflow prevention joint 1 of this embodiment can be easily installed between an upstream drain pipe and a downstream drain pipe that have a difference in elevation, it can more effectively prevent backflow of wastewater and the rise of backflow water than conventional backflow prevention devices that are installed between upstream and downstream drain pipes that do not have a difference in elevation and are at approximately the same level.

[0048] In this embodiment, the inspection port 7 has a third central axis c that extends diagonally upward so as it moves away from the inlet 2, and extends diagonally upward from the body 4 to form an opening. The upper part of the inspection port 7 has the shape of a receiving port, and a stepped portion 70 is formed for detachably supporting the lid portion 8, which will be described later. In addition, a concave first engaging portion 71 is provided on the inner circumferential surface of the inspection port 7 for supporting the lid portion 8 from below and fixing it so that it cannot rotate in the circumferential direction (see Figures 2, 3, and 5).

[0049] As described above, in this embodiment, the inspection port 7 is positioned diagonally upward, so unlike conventional horizontal backflow prevention devices, the drainage inside the joint does not easily overflow even when the cover 8 is opened. Also, by removing the cover 8, the inside of the joint body 10 can be easily accessed, making maintenance and other procedures easy. Furthermore, the inspection port 7 can be effectively utilized as the movable area of ​​the valve body 6, which will be described later, so that the movable space of the valve body 6 can be secured without unnecessarily increasing the size of the backflow prevention joint 1.

[0050] Therefore, in this embodiment, it is preferable that the diameter of the inspection port 7 is the same as the original diameter of the outlet port 3. In particular, by making the diameter of the inspection port 7 the same as the original diameter of the outlet port 3, a movable space for the valve body 6 can be formed on the downstream side (opening side) of the valve body 6 using the inspection port 7. This eliminates the need to provide extra space for the movement of the valve body 6, and allows for an efficient size in which the width of the outlet port 3 and the width of the joint body 10 are approximately the same. Note that "original diameter" refers to the diameter of the inlet port 2 and outlet port 3 when no adapters or the like are attached to the receiving port or spigot port to adjust their diameters.

[0051] On the other hand, the original diameter of outlet 3 may be the same as the original diameter of inlet 2. However, usually the diameters of the upstream and downstream drain pipes are the same, or the diameter of the downstream drain pipe is larger than that of the upstream drain pipe. Therefore, by using an adapter to adjust the diameter, the original diameter of outlet 3 can be made larger than the original diameter of inlet 2, thereby expanding the range of application of the backflow prevention joint 1. As mentioned above, when the original diameter of outlet 3 is the same as the diameter of inspection port 7, the diameter of inspection port 7 will also be larger than the diameter of inlet 2.

[0052] Figure 7a shows a cross-sectional view of a backflow suppression joint 1 in which a first reducing increaser 30 is attached only to the outlet 3 to reduce its diameter to the same as the diameter of the inlet 2. Figure 7b shows a cross-sectional view of a backflow suppression joint 1 in which, as a first application example of the backflow suppression joint 1 shown in Figure 7a, a reducing socket 21 is attached to the inlet 2 to reduce its diameter, and a second reducing increaser 31 is attached to the outlet 3 to adjust (reduce) its diameter to the same as the reduced diameter of the inlet 2.

[0053] As shown in Figures 7a and 7b, in this embodiment, the original diameter of the outlet 3 of the backflow prevention joint 1 is larger than the original diameter of the inlet 2. Therefore, when installing the backflow prevention joint 1 of this embodiment between an upstream drain pipe (not shown) whose downstream end diameter is the same as the original diameter of the inlet 2 and which opens horizontally, and a downstream drain pipe (not shown) whose upstream end opens vertically, the inlet 2 can be connected directly to the upstream drain pipe, and only the outlet 3 can be fitted with a first reducing insert 30 to adjust (reduce) its original diameter to match the diameter of the downstream drain pipe, in other words, the original diameter of the inlet 2, and then the downstream drain pipe can be connected (Figure 7a). Also, if the outlet 3 can be connected directly to the downstream drain pipe, it is not necessary to use the first reducing insert 30.

[0054] Furthermore, in the case of an upstream drain pipe (not shown) and a downstream drain pipe (not shown) with the same layout as in Figure 7a, if the diameter of either drain pipe is smaller than the original diameter of the inlet 2 and the original diameter of the outlet 3, then a reducing socket 21 can be attached to the inlet 2 to adjust (reduce the diameter) its original diameter to match the diameter of the upstream drain pipe and connect it to the upstream drain pipe, and a second reducing increaser 31 can be attached to the outlet 3 to adjust (reduce the diameter) its original diameter to match the diameter of the downstream drain pipe, in other words, the diameter of the inlet 2 reduced by the reducing socket 21 and connect it to the downstream drain pipe (Figure 7b). Also, if the outlet 3 can be connected directly to the downstream drain pipe, it is not necessary to use the second reducing increaser 31.

[0055] Figure 7c shows a cross-sectional view of a backflow suppression joint 1 as a third application example of the backflow suppression joint 1 shown in Figure 7a, in which a first reducing 45° elbow 32 is attached only to the outlet 3 to reduce its diameter and change the direction of outflow. Figure 7d shows a cross-sectional view of a backflow suppression joint 1 as a fourth application example of the backflow suppression joint shown in Figure 7a, in which a reducing socket 21 is attached to the inlet 2 to reduce its diameter, and a second reducing 45° elbow 33 is attached to the outlet 3 to reduce its diameter and change the direction of outflow.

[0056] When installing the backflow suppression joint 1 of this embodiment between an upstream drain pipe (not shown) whose downstream end diameter is the same as the original diameter of the inlet 2 and which opens horizontally, and a downstream drain pipe (not shown) whose upstream end opens diagonally upward, the inlet 2 is connected directly to the upstream drain pipe, and only the outlet 3 is fitted with a first reducing 45° elbow 32 to reduce its original diameter and change the direction of outflow, and then the downstream drain pipe is connected (Figure 7c).

[0057] Furthermore, in the case of an upstream drain pipe (not shown) and a downstream drain pipe (not shown) with the same layout as in Figure 7c, if the diameter of either drain pipe is smaller than the original diameter of the inlet 2 and the original diameter of the outlet 3, then a reducing socket 21 is attached to the inlet 2 to adjust (reduce the diameter) its original diameter to match the diameter of the upstream drain pipe, and the upstream drain pipe is connected. At the outlet 3, a second reducing 45° elbow 33 is attached to adjust (reduce the diameter) its original diameter to match the diameter of the downstream drain pipe, in other words, the diameter of the inlet 2 reduced by the reducing socket 21, and to change the direction of outflow, and the downstream drain pipe is connected (Figure 7d).

[0058] As can be understood by referring to Figures 7a to 7d, the backflow prevention joint 1 of this embodiment can be easily installed between upstream and downstream drain pipes that have a difference in height and various diameters and inclinations, by attaching a reducing socket 21 or the like that matches the diameter of the upstream drain pipe to the inlet 2 as needed, and reducing increases 30, 31 or reducing elbows 32, 33 or the like that that match the diameter and inclination of the downstream drain pipe to the outlet 3 as needed. In this embodiment, the combinations of reducing sockets 21, reducing increases 30, 31 and reducing 45° elbows 32, 33 shown in Figures 7a to 7d are merely examples, and any combination is possible depending on the diameter and inclination of the upstream and downstream drain pipes, and various adapters can be attached as needed.

[0059] The backflow suppression joint 1 of this embodiment includes a valve pipe 5 that communicates with the inlet 2 and protrudes downward from the inlet 2 so as to curve toward the interior of the body 4, penetrating the wall surface of the body 4 (Figures 7a to 7d). The valve pipe 5 does not necessarily have to protrude entirely toward the interior of the body 4 in the circumferential direction; for example, a part of the valve pipe 5, such as the upper half in the circumferential direction, may protrude toward the interior of the body 4. The protruding portion of the valve pipe 5 may be formed integrally with the body 4, or it may be configured as a separate part that can be separated from the body 4.

[0060] Furthermore, a valve seat portion 50 is formed at the open end of the valve pipe 5, which is inclined to approach the inlet 2 from top to bottom. The valve seat portion 50 functions in cooperation with the valve body 6, which will be described later, by contacting the valve body 6, in order to prevent backflow of wastewater.

[0061] In this embodiment, by providing the valve pipe 5, the wastewater that flows horizontally from the inlet 2 into the body 4 can be reliably and smoothly deflected downward. Furthermore, since the valve pipe 5 is cylindrical, if the opening surface cut off by a plane perpendicular to the pipe axis of the valve pipe 5 is made into the valve seat portion 50 at the opening end, the valve seat portion 50 is formed to be approximately circular, and the shape of the valve body 6 that abuts against the valve seat portion 50 can also be approximately circular, thus simplifying the design and molding process.

[0062] Furthermore, as described above, the valve seat portion 50 is inclined such that the protrusion decreases from the top to the bottom. Therefore, the valve body 6, which is suspended from the valve seat portion 50 so as to be able to open and close, forms a gap between itself and the valve seat portion 50 under normal conditions, thereby ensuring the smooth flow of forward-flowing wastewater. In the event of an abnormality (when backflow occurs), the pressure of the reverse-flowing wastewater causes the valve body 6 to come into contact with the valve seat portion 50, effectively suppressing the backflow of wastewater.

[0063] In this embodiment, the joint body 10 is integrally formed from a plastic material. There are no particular limitations on the material used for the joint body 10, and mainly known materials such as plastics can be used. From the viewpoint of having high strength, water resistance, and ease of molding, polyvinyl chloride resin is preferred.

[0064] <Lid> Figure 8 shows a perspective view from above of the cover 8 and valve body 6 of the backflow suppression joint 1 according to this embodiment, and Figure 9 shows a perspective view from below of the cover 8 and valve body 6 shown in Figure 8. Figure 10 shows a front view of the cover 8 and valve body 6 shown in Figures 8 and 9, Figure 11 shows a side view of the cover 8 and valve body 6 shown in Figures 8 and 9, and Figure 12 shows an exploded view of the cover 8 and valve body 6 shown in Figures 8 and 9.

[0065] As shown in Figures 7a-7d and 8-12, the lid 8 has a thick, roughly disc-shaped form, and the valve body 6 is pivotally supported on its lower surface via a suspension arm 82 extending downward. A pair of triangular handles 800 are formed on the upper surface of the lid 8 for gripping and rotating it. Both the lid 8 and the valve body 6 are made of polyvinyl chloride resin, but there are no particular limitations on the materials used; mainly known materials such as plastics can be used.

[0066] More specifically, as shown in Figure 12, the lid 8 consists of a lid body 80 having a handle 800 for opening and closing the inspection port 7, a cap portion 81 fitted to the lower part of the lid body 80, and a suspension arm 82 integrally molded with the cap portion 81 and extending downward from the lower surface of the cap portion 81. In other words, in this embodiment, the lid body 80 and the cap portion 81 are configured as separate and independent parts, and the lid body 80 and the cap portion 81 are rotatable relative to each other in the circumferential direction.

[0067] Furthermore, the upper surface of the cap portion 81 is provided with a pair of auxiliary handles 813 (Figure 12) to facilitate gripping the cap portion 81, and the lower surface of the cap portion 81 has a planar bulge 810 with a different inclination angle from the upper surface of the cap portion 81 to prevent the valve body 6 from unnecessarily rotating too far toward the inspection port 7, i.e., toward the side where the valve body 6 opens.

[0068] The shape and structure of the bulge portion 810 are not particularly limited as long as they can restrict the rotation of the valve body 6 within a certain range. In this embodiment, the bulge portion 810 is provided so as to occupy most of the internal space of the inspection opening 7, and its restricting surface 811 is inclined so as to approach the valve body 6 from bottom to top (Figures 7a to 7d). As a result, the backflow water rising upward from the outlet 3 collides with the restricting surface 811 of the bulge portion 810 and is converted into a flow that pushes the valve body 6 in a direction that closes it from the downstream side, thus making the closing action of the valve body 6 by the backflow water more reliable. Furthermore, when the bulge portion 810 is opened until it contacts the valve body 6, it forms a flow path that curves downward so as to be continuous with the ceiling portion of the valve pipe 5 inside the joint body 10. As a result, even if a large amount of wastewater flows horizontally from the inlet 2, the wastewater can be reliably and smoothly deflected downward.

[0069] Furthermore, in this embodiment, the lower surface of the cap portion 81 is provided with a convex second engaging portion 812 that can be fitted with a concave first engaging portion 71 provided on the inner circumferential surface of the inspection opening 7 described above, and is positioned opposite to it using the side surface of the bulging portion 810. The shape and structure of the second engaging portion 812 are not particularly limited as long as it can be fitted with the concave first engaging portion 71, and may be, for example, a projection that extends vertically on its own from the back surface of the cap portion 81.

[0070] In this embodiment, a groove 814 (Figure 12) is formed on the side surface (circumferential surface) of the cap portion 81, and a packing 83 made of elastomer material is fitted into the groove 814 to improve sealing with the inspection opening 7 (see Figures 7a to 7d). In this embodiment, the lid portion 8 is composed of a lid body 80 and a cap portion 81 with a suspension arm 82 as separate and independent parts, but these may be formed as a single integrated part.

[0071] In this embodiment, when closing the inspection opening 7 using the lid portion 8, first a pair of convex second engaging portions 812 provided on the cap portion 81 are fitted into a pair of concave first engaging portions 71 provided inside the inspection opening 7. The cap portion 81, which supports the valve body 6, is supported from below by the stepped portion 70 inside the inspection opening 7, and is fixed to the inspection opening 7 so as not to rotate in the circumferential direction by the engagement of the second engaging portions 812 and the first engaging portions 71.

[0072] Next, after setting the cap portion 81 inside the inspection port 7, the lid body 80 is placed on top of the cap portion 81 inside the inspection port 7. This ensures that the cap portion 81 is sandwiched between the lid body 80 and the stepped portion 70 of the inspection port 7 without any looseness or rotation. As a result, the valve body 6 supported by the cap portion 81 is precisely set in the predetermined position and can be precisely brought into contact with the valve seat portion 50 inside the joint body 10.

[0073] Furthermore, when removing the cover 8 to open the inspection port 7, the valve body 6 can be easily removed by removing the cover body 80 and cap portion 81 from the inspection port 7 using the reverse procedure described above. Also, if the cover body 80 and cap portion 81 are integrally formed, the valve body 6 can be removed together with the cover 8 when it is removed from the inspection port 7.

[0074] As shown in Figures 1-4, 6, 8, and 9, the backflow prevention joint 1 of this embodiment is equipped with a locking mechanism 9 to prevent the lid 8 from detaching from the inspection port 7 due to an increase in the pressure of water or air inside the joint 1. In this embodiment, the locking mechanism 9 uses a bayonet mechanism that prevents the lid 8 from detaching from the inspection port 7 by rotating the lid body 80 circumferentially relative to the inspection port 7. More specifically, the locking mechanism 9 consists of a pair of crank-shaped projections 90 provided at opposing positions 180° apart on the side surface (circumferential surface) of the lid body 80, and a pair of crank-shaped notches 91 provided at opposing positions 180° apart on the receiving end of the inspection port 7.

[0075] Therefore, when the lid 8 is set into the inspection port 7 with the cap portion 81 that supports the valve body 6, and the lid body 80 is fitted into the receiving port of the inspection port 7, it can be rotated to a position where the projection 90 and the notch 91 engage, thereby locking the cap portion 81 in a way that prevents it from being unintentionally detached from the inspection port 23 without rotating it. In the bayonet mechanism described above, the notch 91 does not necessarily have to be a crank-shaped projection, but may be a simple rod-shaped projection, for example. Also, the locking means 9 does not necessarily have to be a bayonet mechanism, and especially when the lid body 80 and the cap portion 81 are integrally formed, known engaging means such as a hook that locks the lid 8 from above can also be used.

[0076] <valve body> As shown in Figures 7a-7d and 8-12, in this embodiment, the valve body 6 has a circular shape so that it can contact the circular valve seat portion 50 in a liquid-tight manner when viewed from the front (Figure 10), and in a side view, it has a recess 60 that is recessed from the downstream side to the upstream side so that it receives a large force (resistance) from reverse flow drainage and a small force (resistance) from forward flow drainage (Figures 8 and 11).

[0077] The valve body 6 is supported in a rotatable manner so as to be able to open and close relative to the valve seat portion 50, but there are no particular limitations on the support position or support method, and it may be supported by, for example, the inner wall of the joint body 10, the valve tube 5, or the cover portion 8.

[0078] In this embodiment, the valve body 6 has a horizontally oriented L-shaped support arm 61 on its upper part, and is pivotally supported on the suspension arm 82 of the cover 8 via the support arm 61, either by a pin or directly. Furthermore, when the cover 8 is set in a predetermined position inside the inspection opening 7, the valve body 6 is pivotally supported above the valve pipe 5 and at a position (fulcrum p) offset towards the inlet 2 side from the open end of the valve pipe 5 (valve seat 50), so that it can open and close relative to the valve seat 50. It is preferable that the shaft hole of the valve body 6 be formed to be slightly larger than the shaft diameter of the pin so that the valve body 6 can rotate smoothly, and in order to improve the sealing performance with the valve seat 50, it may be made into an elongated hole shape so that there is no play between the pin and the valve body 6 when the valve body 6 abuts against the valve seat 50.

[0079] Therefore, when the valve body 6 is suspended, it is positioned at an inclination so that it approaches the inlet 2 from top to bottom, as shown in Figures 7a to 7d. When the valve body 6 is positioned at an inclination as described above, backflow water flowing horizontally from the outlet 3 towards the front of the valve body 6 and backflow water rising upward from the outlet 3 will collide with the recessed downstream surface of the valve body 6 rather than the upstream surface, thus making the action of closing the valve body 6 with backflow water more reliable.

[0080] Furthermore, as described above, by positioning the pivot point p of the valve body 6 at a location offset towards the inlet 2 side from the valve seat portion 50, the trajectory of the lower end of the valve body 6, that is, the trajectory of the part of the valve body 6 furthest from the pivot point p, approaches the inlet 2 and the valve seat portion 50. As a result, without changing the opening and closing angle of the valve body 6, the range of motion of the valve body 6 in the outlet region of the valve pipe 5 can be substantially narrowed, and the backflow suppression joint 1 can be made more compact.

[0081] More specifically, as shown in Figure 7a, the valve body 6 is preferably pivotally supported at a pivot point p that is offset such that L / D is preferably 0.15 to 0.45, more preferably 0.20 to 0.40, when D (mm) is the outer diameter of the open end (valve seat portion 50) of the valve pipe 5 and L (mm) is the distance from the open end face of the valve pipe 5 to the pivot point p of the valve body 6. In this case, the center of gravity of the valve body 6 will be located downstream of the contact surface that contacts the valve seat portion 50 of the valve body 6 when the valve body 6 is suspended.

[0082] If L / D is set to less than 0.15, the valve body 6 cannot be tilted sufficiently so that the backflow water rising upward from the outlet 3 first hits the downstream surface of the valve body 6. This makes the valve body 6 more likely to move in the opening direction, and it becomes impossible to adequately block the flow of backflow water. Furthermore, it becomes impossible to narrow the range of motion of the valve body 6 in the outlet region of the valve pipe 5 to the extent that it contributes to the compactness of the backflow suppression joint 1. On the other hand, if L / D is set to more than 0.45, it becomes necessary to secure space for the movement of the support arm 61 of the elongated valve body 6, which leads to the disadvantage of the joint body 10 becoming unnecessarily large.

[0083] In addition, in the backflow suppression joint 1 of this embodiment, a stopper (not shown) may be provided at the pivot point p of the valve body 6 to prevent the valve body 6 from rotating unnecessarily too far toward the inspection port 7, i.e., toward the opening side. If a stopper is provided at the pivot point p of the valve body 6 as described above, the bulge 810 provided on the lower surface of the cover 8 for the same purpose can be omitted.

[0084] Furthermore, in the backflow suppression joint 1 of this embodiment, a buoyancy generating part (not shown) having a specific gravity less than that of water may be provided upstream of the valve body 6 and on the inlet 2 side of the vertical plane passing through the fulcrum p of the valve body 6. By positioning the buoyancy generating part eccentrically upstream of the valve body 6 in this way, when backflow occurs, the buoyancy generating part is pulled up in the direction of closing the valve body 6 by the backflow rising upward from the outlet 3, thereby more reliably preventing malfunction of the valve body 6. [Explanation of Symbols]

[0085] 1. Backflow prevention joint 10. Fitting body 2...Inlet 20····Sort opening step section 21.. Reducing socket 3... Outlet 30.....First Diameter Increaser 31..Second reducing increaser 32.....First reducing 45° elbow 33...Second reducing 45° elbow 4. Torso 5. Valve tube 50... Valve seat 6. Valve body 60····recess 61. Support arm 7...Inspection hatch 70... Step section 71...First engagement part 8...Lid part 80····Lid body 800...handle 81... Cap part 810...bulge 811...Regulations 812...Second engaging part 813...Auxiliary handle 814... Groove 82.. Suspension arm 83...Gasket 9. Locking mechanism 90...Protrusion 91...Notch a·····First central axis b....Second central axis c·····Third central axis p...Fulcrum D·····Outer diameter of the opening end (valve seat) (mm) L·····Distance from the opening end face to the pivot point of the valve body (mm)

Claims

1. Inlet and Outlet and A body portion connecting the inlet and the outlet, A valve tube is provided that communicates with the inlet and protrudes into the interior of the body, A valve seat portion formed at the open end of the valve pipe, which is inclined to approach the inlet from the top to the bottom, and A valve body is rotatably supported at the upper part of the valve tube and at a position offset toward the inlet side from the open end of the valve tube, A backflow suppression joint equipped with [a specific feature].

2. The backflow suppression joint according to claim 1, characterized in that when the outer diameter of the open end of the valve pipe is D (mm) and the distance from the open end face of the valve pipe to the pivot point of the valve body is L (mm), L / D is 0.15 or more and 0.45 or less.

3. The backflow suppression joint according to claim 1, characterized in that when the valve body is suspended, the center of gravity of the valve body is located downstream of the contact surface of the valve body that contacts the valve seat portion.

4. The backflow suppression joint according to claim 1, characterized in that when the valve body is suspended, the valve body is inclined such that the contact surface with the valve seat portion approaches the inlet side as it moves from the top to the bottom.

5. The backflow suppression joint according to claim 4, characterized in that the valve body has a recess that extends from the downstream side to the upstream side.

6. The inlet is formed to have a first central axis extending horizontally, and The backflow suppression joint according to claim 1, characterized in that the outlet is formed to have a second central axis extending in the vertical direction.

7. An inspection port having a third central axis that extends from the body and extends upward diagonally away from the inlet, The invention further comprises a lid that can be detachably attached to the inspection opening, and The backflow suppression joint according to any one of claims 1 to 6, characterized in that the valve body is rotatably supported on the cover.

8. The lid portion includes a cap portion that is attached to the inspection opening so as not to rotate in the circumferential direction, It consists of a lid body which is mounted on the cap portion so as to be rotatable in the circumferential direction relative to the inspection opening, and The backflow suppression joint according to claim 7, characterized in that the valve body is supported by the cap portion.

9. The inner circumferential surface of the inspection opening is provided with a first engaging portion that fixes the cap portion to the inspection opening so that it cannot rotate in the circumferential direction, and The backflow suppression joint according to claim 8, characterized in that the cap portion is provided with a second engaging portion that engages with the first engaging portion.

10. The body is equipped with a locking mechanism to prevent the lid from detaching from the inspection opening due to an increase in the pressure of water or air inside the body, The backflow suppression joint according to claim 9, characterized in that the locking means is a bayonet mechanism which engages the lid with the inspection opening by rotating the lid circumferentially with respect to the inspection opening.

11. The backflow suppression joint according to claim 7, characterized in that the diameter of the inspection port is the same as the diameter of the outlet.

12. The backflow suppression joint according to claim 11, characterized in that the diameter of the outlet is larger than the diameter of the inlet.

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