System and method for preventing backflow in vertical rainwater drainage pipes with multiple lateral branches

Abstract

The present invention provides a branch pipe system that prevents backflow in rainwater drainage for wind and rain spaces, particularly in downpipes and related branching systems used in high-rise buildings. [Solution] The branch pipe equipment 295 for branching from a vertical pipe comprises a branch connection 305 attached to the vertical pipe having a constricted cross section in the vertical portion that forms a nozzle, wherein the nozzle comprises the branch connection 305 configured to increase the velocity head of water passing through the nozzle, an expansion chamber located directly below the nozzle and having a cross-sectional area larger than the cross-sectional area of ​​the vertical pipe, a branch section protruding from the expansion chamber, a floor outlet 320, and a branch pipe connecting the branch section to the floor outlet 320.

Description

Technical Field

[0001] The present invention relates to rainwater drainage for a风雨空间 (wind and rain space). In particular, the present invention relates to vertical downspouts and related branches such as those used in high-rise buildings.

Background Art

[0002] A rainwater pipe having a multi-stage horizontal branch connection portion has a risk of backflow of water through the horizontal branch. This risk is extremely difficult to predict with the current design principle of gravity rainwater vertical downspouts.

[0003] Important factors causing backflow in the horizontal branch are as follows. · Release of air trapped in the pipe; · Impossibility of predicting two-phase flow characteristics when the flow rate increases beyond the safety limit that can maintain a clear separation between air and water.

[0004] To prevent the above uncertainties, the flow rate of the vertical stack must be limited to a very small flow capacity. Rainwater drainage standards in many countries adopt the principle of not permitting the connection of horizontal branches to vertical roof drainage pipes in order to prevent the problem of backflow.

[0005] At a very low flow rate where the water flow does not affect the air flow, there is no risk of backflow. However, as the flow increases, the filling rate of water in the pipe increases. This increase in water flow affects the air inside the vertical pipe. As the downward water flow increases, additional air may be drawn in from the upper part of the vertical pipe (located on the roof) or from a horizontal branch located in a higher part of the stack.

[0006] When the air taken in together with the water flow, such as in a pipe that discharges vertically into an open space, can move freely downward and be freely discharged at the downstream end, there is no risk of backflow.

[0007] It should be noted that the term "风雨空间" in the original text seems to be a specific term in the original language context. If there is a more accurate English equivalent, it should be used instead. Here, a literal translation is provided for the time.however, • Downstream, the pipe extends horizontally for a long distance. • An elbow exists downstream. • Flows from other stacks merge, or • The pipe discharge is submerged due to overflow from the external drain. In situations where air cannot freely flow out at the downstream end of the pipe, the air escapes through the multi-stage lateral branch connection, particularly in the lower part of the stack.

[0008] The air escaping through the lateral branching creates three problems. - It obstructs the effective flow of water to the floor outlet (which forms the entrance to the lateral branch). • It obstructs the effective flow of water through the lateral branch pipes. • The water flowing within the vertical stack is pushed out through the lateral branch, thus causing backflow. [Overview of the Initiative]

[0009] A first aspect of the present invention provides a branch pipe system for branching from a vertical pipe, the branch pipe system comprising a branch connector attached to the vertical pipe having a tapered cross section in the vertical portion forming a nozzle, the nozzle comprising: a branch connector configured to increase the velocity head of water passing through the nozzle; an expansion chamber located directly below the nozzle and having a cross-sectional area larger than that of the vertical pipe; a branch section protruding from the expansion chamber; a floor outlet; and a branch pipe connecting the branch section to the floor outlet.

[0010] A second aspect of the present invention provides a floor outlet for receiving water inflow, the floor outlet comprising a socket for connection to a pipe, and an inlet having two openings: a first opening for receiving water inflow and a second opening for releasing air, the openings being in fluid communication with the socket.

[0011] A third aspect of the present invention provides an elbow for providing an angled connection between two pipes, the elbow having an inner radius and an outer radius, the inner radius being larger than the diameter of the pipes.

[0012] A fourth aspect of the present invention provides an air discharge device to be attached to a pipe, the air discharge device comprising a housing that defines a vertically oriented internal chamber, an opening at the base of the chamber for receiving air from the pipe, and a vent at the top of the chamber for releasing the received air, wherein the height of the chamber is greater than or equal to the width of the chamber. [Brief explanation of the drawing]

[0013] It would be convenient to further describe the present invention with reference to the accompanying drawings illustrating possible configurations of the invention. Other configurations of the invention are possible, and therefore, the details in the accompanying drawings should not be understood as prejudicing the generality of the above description of the invention.

[0014] [Figure 1] This is an elevation view of a vertical pipe with a branch in a flow state of stage 2. [Figure 2] This is an elevation view of a vertical pipe with a branch in flow states 3 and 4. [Figure 3] This is a schematic elevation view of a vertical pipe and a horizontal branch. [Figure 4A] This is an elevation view of the joint according to one embodiment of the present invention. [Figure 4B] This is an isometric view of an elbow according to one embodiment of the present invention. [Figure 4C] This is an isometric view of the outlet according to one embodiment of the present invention. [Figure 4D] This is an air release device according to one embodiment of the present invention. [Figure 5] This is a schematic elevation view of a vertical pipe having a joint according to one embodiment of the present invention. [Figure 6] This is a schematic elevation view of a joint according to one embodiment of the present invention. [Figure 7A] Schematic elevation view of an elbow according to the prior art subject to a countercurrent state. [Figure 7B] Schematic elevation view of an elbow according to the prior art subject to a countercurrent state. [Figure 7C] Schematic elevation view of an elbow according to the prior art subject to a countercurrent state. [Figure 8] Schematic elevation view of an elbow according to an embodiment of the present invention. [Figure 9A] Schematic elevation view of an outlet according to an embodiment of the present invention. [Figure 9B] Schematic elevation view of an outlet according to an embodiment of the present invention. [Figure 10A] Schematic elevation view of an air release device according to an embodiment of the present invention. [Figure 10B] Schematic elevation view of an air release device according to an embodiment of the present invention. [Figure 11A] Isometric view of various configurations of a vertical pipe and a horizontal branch according to some embodiments of the present invention. [Figure 11B] Isometric view of various configurations of a vertical pipe and a horizontal branch according to some embodiments of the present invention. [Figure 11C] Isometric view of various configurations of a vertical pipe and a horizontal branch according to some embodiments of the present invention. [Figure 11D] Isometric view of various configurations of a vertical pipe and a horizontal branch according to some embodiments of the present invention.

Mode for Carrying Out the Invention

[0015] The flow along the vertical pipe undergoes the following stages (as the flow increases). · Stage 1: A very low flow rate where there is a clear separation between air and water. The water typically flows along the inner surface of the pipe wall and can be described as an annular flow. · Stage 2: A low flow rate where the water flow affects the air flow in the pipe. This stage of the flow brings additional air into the pipe and causes an accumulation of air at the bottom of the pipe. Stage 3: Two-phase flow stage: Pressure fluctuations occur within the piping, and air and water mix in the flow. The flow conditions can become extremely unstable and unpredictable. Stage 4: The flow rate reaches a stable pressure flow state where the pressure is relatively stable. This state is characterized by the presence of small bubbles mixed with the water flow. • Stage 5: The maximum possible flow rate at which the flow reaches the flow state throughout the hole in the vertical stack.

[0016] The risk of backflow arises in stages 2, 3, 4, and 5. Conventional gravity design principles limit the capacity of the gravity system to the flow rate in stage 1 in order to prevent any backflow.

[0017] Figure 1 shows a downpipe system 5 comprising a vertical pipe 10 with a lateral branch 15. In stage 2, air 30 is carried downward by the water flow. As the air pressure 20 increases, a problem arises in which air 35 is pushed laterally through the lateral branch. The escaping air intersects with the water flowing downward along the inner surface of the pipe wall, and thus pushes the water 25 into the lateral branch.

[0018] This causes water to accumulate in the lateral branch, eventually preventing air from freely escaping through the branch pipe. When this happens, the air pushes the water upstream along the branch pipe, causing a backflow.

[0019] Figure 2 shows the same equipment 5 as in Figure 1, but the water flow increases as it progresses from stages 3 and 4 to stage 5. In this stage, the water flow has the characteristics of a pressurized flow, with the downward flow containing entrained air, exhibiting a two-phase flow. Because the flow passing through the branch connection has a pressure higher than atmospheric pressure, the water 45 is pushed out through the branch connection by the water pressure, causing a backflow.

[0020] The airflow conditions at a lateral branch differ based on the various flow conditions within the vertical stack. As the flow through the vertical stack increases, various stages of airflow occur. Stage 1: The minimum amount of air flowing outward against the direction of the water flow. Stage 2: The air flows outward against the direction of the water flow to its maximum extent. • Stage 3: The amount of air flowing outward against the direction of the water flow is minimal (same as Stage 1). • Stage 4: Neutral state where air movement is minimal Stage 5: Inward air movement following the direction of water flow.

[0021] The critical condition occurs in the stage 2 flow of the branched pipe, which also occurs in the stage 2 and stage 3 flows of the vertical pipe. The solution to backflow needs to address the situation in the branched pipe where the outward flow of air against the direction of water flow is greatest.

[0022] Figure 3 shows locations in a vertical rainwater drainage pipe 50 with multi-stage lateral branch connections where backflow is likely to occur. • Positioned along the vertical stack 55. • Because the escaping air pushes the water outwards through the lateral branch from the stack. Due to pressure fluctuations within the vertical cross-section of the pipe. • The location of the connection point 60 between the vertical stack and the horizontal branch. • Located along the horizontal branch pipe 65 where the flow changes direction from horizontal to vertical. • Location of the water inlet point 70 to the lateral branch (e.g., balcony floor exit).

[0023] The present invention relates to several embodiments, each of which can be incorporated to solve the problem at the location identified in Figure 3. These various embodiments may be used individually as needed, but it will be understood that they may be used in combination with any or all of the other embodiments to form a system-wide solution when a system-wide solution is required in a particular application.

[0024] Various embodiments configured to solve situations in different locations are shown in Figures 4A to 4D. Figure 4A: Backflow prevention joints 75 located at all connection points of lateral branches to the vertical pipe. Figure 4B: Adaptive elbow 80 positioned at all angle changes between vertical and horizontal in a branch pipe. Figure 4C: Adaptive floor outlet 85 into which water enters the branch pipe. Figure 4D: Adaptive air release device 90 that can be incorporated into the backflow prevention joint and other locations within the branch pipe.

[0025] Figure 5 shows a vertical pipe, which has branches extending from it. Each branch includes a backflow prevention joint 75.

[0026] The backflow prevention joint 75 includes a constricted cross section 120 that forms a nozzle level 124 having an opening 132 for the branch 134, as shown in Figure 6. The constriction causes an accumulation of water 100, 105 above the joint 75 that forms a pressure head. This changes the flow pattern from gravity-induced unpressurized flow to pressurized flow, and the nozzle converts the pressure head into a high-velocity head in the form of a high-velocity jet 130 of water that has passed through the branch, thus creating an air-water separation zone 125 that allows trapped air to escape through the branch 134 in both vertical and horizontal directions (135). At high flow rates in the vertical pipe, the pressure jet achieves extremely high velocities that produce an suction effect at the connection point with the transverse branch. This increases the flow capacity of the transverse branch.

[0027] The wider separation zone 125 is also open to atmospheric pressure through branch 134, allowing the water jet to expand and thus to return to a gravity-driven flow.

[0028] At every connection point, the nozzle creates a pressure flow state above the nozzle while simultaneously generating a sudden pressure change below the nozzle. This occurs at every branching point, regardless of the location of the joint in the vertical piping and the height of the piping. Therefore, the flow state within the vertical stack is divided into small, controlled pressure flow segments. Pressure fluctuations within the vertical stack are eliminated.

[0029] This allows the system to operate under controlled pressure flow conditions, achieving much higher flow rates compared to conventional solutions that are only safe in Stage 1 (extremely low flow rate conditions).

[0030] A controlled water level at the lateral branch is crucial to allow air to escape through the lateral branch pipe without interfering with the water flow. The water flow must be designed to maintain an open channel state in the horizontal section of the branch pipe.

[0031] Conventional gravity drainage pipe designs for horizontal pipes allow water depths of up to 70% of the pipe's total cross-sectional depth, but this filling rate does not allow sufficient space for air to escape freely.

[0032] The maximum water depth through which air can be freely discharged through a branch pipe is 50% of the total depth of the pipe's cross-section.

[0033] As explained with reference to Figures 11A to 11D, for water depths exceeding 50%, a special air release device 90 can be incorporated into the backflow prevention joint.

[0034] Figures 7A to 7C show further locations in branch pipe systems that experience problems as a result of backflow. When the water flow changes direction downward from the horizontal section of the branch pipe to the vertical section of the pipe, the configuration of the elbow / bend 140 at the change of direction is important in preventing backflow.

[0035] When the airflow 145 from the vertical section of the pipe intersects with the water flow 150, which may protrude across the airflow path due to the shape of the bend between the horizontal upstream section and the vertical downstream section, there is a risk of backflow. In fact, this acts as a discontinuity for the water flow 150, leading to its separation from the pipe at this point 152. The upward airflow 145 pushes the water back 155 (147, 160), causing a buildup of water upstream of the bend, and eventually forming a plug 166 of water that can be pushed back upstream over a long distance, causing backflow.

[0036] Bends with sharp inner edges 152 (typical of sharp 90-degree plastic fittings) tend to cause water to overshoot away from the inside of the pipe wall, resulting in a protrusion of flow across the center of the vertical section of the pipe.

[0037] Figure 8 shows a solution to this problem using an adaptive elbow 170. Having a curved surface with an inner diameter 172 on the elbow helps to keep the water flow 190 along the lower part of the horizontal pipe by providing a continuous surface and thus preventing separation between the water flow and the pipe. The water 195 follows the bend along the wall of the pipe inside the bend. This prevents intersection between the water flow and the airflow 175, 180, 185 and keeps the airflow separated from the water flow in changes of flow direction.

[0038] According to the present invention, an elbow 170 having a minimum inner diameter corresponding to twice the inner bending radius, which is 0.3 times the diameter of the pipe, is used to ensure that water flow does not intersect with air flow to a depth of up to 50%.

[0039] The enlarged portion 178 in the outer radius of the elbow provides additional air space to avoid interference between airflow and waterflow. For this purpose, the cross-sectional area of ​​the elbow, defined by the line 171 connecting the centers 173 and 174 of the inner and outer radii, is larger than the cross-sectional areas of the upstream and downstream portions of the elbow, including the socket that connects the elbow to the pipe.

[0040] In further embodiments, the radius of the inner portion 172 of the elbow may be greater than the outer radius 176 of the elbow. Typically, elbows of the prior art have equal radii, or in some cases, the inner radius is smaller than the outer radius. In further embodiments of the present invention, the inner radius can be made larger to prevent separation as water flows near the curve, and the outer radius can be made smaller to create additional space for air to flow and remain separate from the water flow. Thus, as the shape conforms to a right angle, the outer radius may approach zero.

[0041] In a further embodiment, Figures 9A–9C show a floor outlet 200 used as the water inlet point to the lateral branch. This is also the outlet point for air escaping from the lateral branch.

[0042] Collisions between outflowing air and inflowing water can hinder effective drainage, potentially preventing water from entering the outlet and subsequently the branch pipe.

[0043] In this embodiment, the floor outlet 200 has a horizontal inlet 208, which ensures that the upper part of the piping moves into a chamber 240 having a larger cross-sectional area than the inlet and therefore enlarged relative to the inlet, the chamber having an upper and lower section. Note that although the figure shows a horizontal inlet, the inlet may also be vertical. In a further alternative embodiment, an inlet having two openings 214, 215, with an elbow as shown in Figure 8 attached to or integrated with the inlet, is located at the other end of the outlet 200 and communicates with the inlet. The first opening 215 is positioned to receive the inflow of water, and the second opening 214 is positioned to allow air to escape from the pipe. The air at the top of the pipe cross-section is directed toward the center of the floor outlet, where it can escape (230) through the second opening 214 without interfering with the water 220 flowing in through the first opening 215. The entrance to the second opening is bounded by an inner edge 213 connected to the canopy 210. The first opening is bounded by an outer edge 205 and an inner edge 213. When arranging the floor outlet, despite the conventional incline for directing water towards the entrance, the outer and inner edges are positioned to be coplanar with the floor surface. Thus, the water flow 220 received by the outlet 200 can be guided through the first opening 215, to the lower part 235 of the chamber 240, and then flow into the horizontal pipe 208 (225).

[0044] The floor outlet 200 has the following two main features: A vertically enlarged air chamber 240 at the connection between the branch pipe 208 and the floor outlet 205. This enlargement 240 allows an additional upper air space to direct airflow toward the central vent opening. An extended semicircular canopy 210 extends from the wall of the floor outlet toward the center, guiding the airflow so that it is released at the center of the outlet. This separates the airflow released outwards from the floor outlet from the water flow into the floor outlet.

[0045] Figure 10A shows the air release component 245. The air release component 245 is configured to be used near a branch to facilitate the release of trapped air and thus help overcome the problem of backflow at the branch. Therefore, it communicates with the branch and is located vertically above the branch, though not necessarily directly above it. Although it may be installed separately from other embodiments of the invention, when used in conjunction with, for example, a backflow prevention joint, the air release component allows for direct release of air very close to the connection point of the joint, thus reducing / eliminating the need to release air through the branch pipe. This allows the branch pipe to drain in its entirety, i.e., 100% water, thus greatly improving drainage capacity. The chamber within the housing may have a height greater than the width of the chamber. It may also have a cross-sectional area greater than the cross-sectional area of ​​the branch or branch pipe.

[0046] The air release device 245 includes a housing 250 having an upper part 255. At the base of the device is an opening 265 that fits into a socket or other mounting part on or near the joint. The opening 265 allows air to escape from the branch pipe. Air enters the chamber 285 and passes through a central tray 270, which in this case is an inverted cone-shaped plate. The tray 270 includes a central vent 273 and peripheral vents 271, 275 around the tray 270. The conical shape of the tray allows the ball 277 to sit inside the device 245 when not in operation. As the air enters the chamber 285 and passes through the tray 270 (280), the air eventually exits through a vent 260 in the upper part 255 of the device and thus exits the device.

[0047] A floating ball 277 is incorporated into the device, and the ball rises and falls (279) based on the water level inside the device, ensuring that the device automatically seals the vent 260 if water is introduced into the device.

[0048] Figure 10B shows an alternative configuration in which one or more flaps 274 are attached to the upper part 255 of the device and are arranged to move from an open position to a closed position (276) to seal the upper vent 260 when water flows in from the base.

[0049] It can be seen that the ball functions in a similar way to a one-way valve, and therefore the ball can be replaced with a freely moving disc that floats above the rising water level and seals the vent.

[0050] As described above, the present invention includes four distinct embodiments as shown in Figures 4A to 4D. These components can be used individually, or they can be used together to form a branch pipe system.

[0051] For example, Figures 11A to 11D show various combinations that can be used in such branching pipe systems, and these combinations are intended to provide continuous air paths and continuous inflow paths that are separated from each other to prevent air from being drawn into the branching pipes.

[0052] Figure 11A: High filling rate with vertical drop incorporated into branch pipe: Branching equipment 295 having a branching joint 305 equipped with an air discharge device 310, two elbows 315, and a floor outlet 320;

[0053] Figure 11B: Low filling rate with vertical drop incorporated into branch pipe: A branching device 325 having a branching joint 305, two elbows 315, and a floor outlet 320;

[0054] Figure 11C: High packing rate with branch pipe directly connected to backflow prevention joint: A branching device 330 having a branching joint 305 equipped with an air discharge device 310 and a floor outlet;

[0055] Figure 11D: Low filling rate where the branch pipe is directly connected to the backflow prevention joint: Branching equipment 335 having a branching joint 305 and a floor outlet 320;

[0056] Each of these branching pipe systems includes various components to achieve high flow rates by utilizing the principle of pressurized flow while effectively preventing backflow in lateral branching.

Claims

1. A branch pipe system for branching from a vertical pipe, A branch connection attached to the vertical pipe having a narrowed cross section forming a nozzle in the vertical portion, wherein the nozzle is configured to increase the velocity head of the water passing through the nozzle, An expansion chamber located directly below the nozzle and having a cross-sectional area larger than the cross-sectional area of ​​the vertical pipe, A branch portion protruding from the expansion chamber, Floor exit and A branch pipe connecting the aforementioned branch section to the floor outlet, Equipped with, The aforementioned floor outlet is configured to accept the inflow of water. An outlet for connecting to a pipe, An inlet having an open outer opening for receiving water inflow and an open inner opening for releasing air, wherein the outer opening and the inner opening are in fluid communication with the insertion port, The entrance comprises an inner edge portion and an outer edge portion that define the inner opening and the outer opening, The inner opening is defined by the inner edge portion. A branch pipe system in which the outer opening is determined by the outer edge and the inner edge such that the inner opening is located within the outer opening and the inner edge is common between the outer opening and the inner opening.

2. The branch pipe equipment according to claim 1, further comprising a chamber located midway between the insertion port and the opening, wherein the chamber has a larger cross-sectional area than the insertion port.

3. The branch pipe equipment according to claim 2, wherein the chamber includes an upper part configured to receive air from the pipe and release the air to the inner opening, and a lower part configured to receive inflow from the outer opening and guide the inflow to the pipe.

4. The branch pipe equipment according to any one of claims 1 to 3, wherein the outer edge and the inner edge are located on the same plane as the floor on which the floor outlet is located.

5. The chamber includes a canopy that covers the upper part of the chamber, The branch pipe equipment according to claim 3, wherein the canopy forms a first conduit through which air flows from the insertion port located below the front of the inlet to the inner opening, and the canopy forms a second conduit through which water flows from the front of the inlet to the rear of the inlet, thereby guiding the water flow through the rear of the inlet to the insertion port.

6. The present invention further includes an air discharge device attached near the aforementioned branching portion and communicating with the aforementioned branching portion, The aforementioned air release device is The housing defines the internal chamber oriented vertically, The opening at the base of the internal chamber for receiving air from the branch pipe, The upper vent of the internal chamber for releasing the received air, It is equipped with, The branch pipe equipment according to any one of claims 1 to 5, wherein the height of the internal chamber is greater than or equal to the width of the internal chamber.

7. The system further includes a tray provided within the internal chamber and extending horizontally across the internal chamber, The branch pipe equipment according to claim 6, wherein the tray includes a vent configured to allow air to pass through the tray.

8. The air release device further includes a ball located above the tray within the internal chamber, The branch pipe equipment according to claim 7, wherein the ball is configured to float when water flows in from the base of the internal chamber and to seal the upper vent hole.

9. The branch pipe equipment according to any one of claims 6 to 8, wherein the air discharge device further includes at least one flap mounted adjacent to the top of the air discharge device within the internal chamber, the flap being configured to move from an open position to a closed position, to seal the upper vent when water flows in from the base.

10. The branch pipe equipment according to any one of claims 1 to 9, wherein the branch pipe includes a first elbow adjacent to the branch for guiding the pipe horizontally.

11. The branch pipe installation according to claim 10, wherein the branch pipe includes two additional elbows between the first elbow and the floor outlet.

12. At least one of the first elbow and the additional elbow is It has an inner radius and an outer radius, The branch pipe equipment according to claim 11, wherein the inner radius is larger than the diameter of the branch pipe.

13. The branch pipe equipment according to claim 12, wherein the outer radius is smaller than the diameter of the pipe.

14. The branch pipe equipment according to claim 12, wherein the outer radius is smaller than the inner radius.

15. The branch pipe equipment according to claim 12, wherein twice the inner radius is 0.3 or more of the diameter of the branch pipe.

16. The branch pipe equipment according to claim 12, wherein the cross-sectional area of ​​the elbow along the line connecting the centers of the inner radius and the outer radius is larger than the cross-sectional area of ​​the pipe to which the elbow is connected.

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