Drainage assembly and method

Abstract

A collecting assembly for connection with a downpipe, the assembly comprising: a collecting pipe, the upstream diameter of the collecting pipe being equal to the diameter of the downpipe, the outlet diameter of the collecting pipe being smaller than the upstream diameter; the collecting pipe is positioned in the downpipe, so that an outlet hole of the outlet part is concentric with the downpipe, and the outlet hole faces downwards; and a flow concentration section disposed on the downpipe, the flow concentration section enabling fluid communication between a point adjacent to the outlet hole and a point outside the downpipe; in use, water is arranged to flow through the outlet aperture, thereby forming an annular space around the flow of water such that air in the annular space can be released along the fluid path.

Description

Technical Field

[0001] The present invention relates to drainage systems, and in particular to drainage systems for multi-story / repetitive floor drainage (eg balcony, corridor) for draining rainwater into vertical downpipes. Background Art

[0002] Gravity drainage systems with multiple floors / repeated levels (e.g. balconies, corridors, etc.) are at risk of backflow when draining if the system is not sized correctly. Backflow is difficult to predict based on existing gravity drainage system design principles. The main cause of backflow is air escaping from the gravity flow path through openings. Backflow is exacerbated when the drainage of a gravity drainage system is obstructed, such as a flooded discharge due to flooding of the external drain outlet, undersized drain pipes, etc.

[0003] To prevent this uncertainty, the flow rate in the vertical channels must be limited to very low velocities. This creates a central core space that allows air to escape vertically upwards, rather than being exhausted through repeated layer drains.

[0004] Most stormwater drainage specifications recommend a fill level of between 0.2 and 0.33 for vertical pipes, such as the British Standard and European Standard BS EN 12056-3. This means that more than 67% of the pipe cross section is filled with air in the central core. The purpose of this is to avoid any pressure fluctuations within the gravity system and to always keep the system pressure at atmospheric pressure.

[0005] However, these stormwater drainage codes are all for roof gravity drainage. It does not mention anything about repeated layer drainage. From the experience of repeated layer drainage, repeated layer drainage is more prone to backflow due to the large number of air inlet and outlet points in the pipe. The most reliable way to reduce the chance of backflow is to use large vertical pipes or limit the capacity of the gravity system. However, such a setup will make the gravity system inefficient. Summary of the invention

[0006] In a first aspect, the present invention provides a collecting assembly for connecting to a downpipe, the assembly comprising: a collecting pipe, wherein the upstream diameter of the collecting pipe is equal to the diameter of the downpipe, and the diameter of the outlet portion of the collecting pipe is smaller than the upstream diameter; the collecting pipe is positioned in the downpipe so that the outlet hole of the outlet portion is concentric with the downpipe and the outlet hole faces downward; and a flow concentrating section provided on the downpipe, wherein the flow concentrating section enables fluid communication between points adjacent to the outlet hole and points outside the downpipe; in use, water is arranged to flow through the outlet hole, thereby forming an annular space around the water flow, so that air in the annular space can be released along the fluid path.

[0007] In a second aspect, the present invention provides a method for releasing air trapped in a downpipe, the method comprising the following steps: causing water to flow around a hole in the downpipe into a header coaxially positioned to the downpipe; reducing the diameter of the water flow to be smaller than the diameter of the downpipe as the water flows through the header; causing the water to flow out from a concentrically arranged outlet hole of the header, thereby forming an annular space around the outflowing water flow; providing a fluid path between a point adjacent to the outlet hole and a point outside the downpipe; thereby releasing air trapped in the annular space along the fluid path.

[0008] The present invention provides a current collecting assembly, which can be installed at a key position of a pipeline system, such as a water inlet, and water entering the pipeline system from the key position can easily prevent air from being released from the system.

[0009] In summary, the present invention provides a manifold that acts as a transition portion that reduces the upstream diameter to a smaller diameter, collects the falling water flow to a central guide column to prevent the water flow from flowing in a circular manner. This forms an annular space around the central guide column in the lower pipe. This can achieve a dual effect, even if the incoming water enters the system in the form of a downward circular flow, while releasing the air in the system to prevent the air from being blocked by one or both of the upstream pipe flow or the incoming flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The possible configurations shown in the drawings of the present invention are convenient for further describing the present invention. The present invention may also have other configurations, and therefore, the particularity of the drawings should not be understood as superseding the generality of the previous description of the present invention.

[0011] FIG1 is a cross-sectional view of a gravity rainwater assembly according to the prior art;

[0012] Figure 2 is a cross-sectional view of a gravity rainwater assembly according to one embodiment of the present invention;

[0013] FIG. 3A to FIG. 3C is an isometric view of a gravity rainwater assembly according to a second embodiment of the present invention; and

[0014] Figure 4 are various cross-sectional views of gravity rainwater assemblies according to various embodiments of the present invention. DETAILED DESCRIPTION

[0015] FIG. 1 shows a prior art piping system in which a water inlet (e.g., a balcony gully 25) receives a surface water flow 8. In this case, the gully 25 is part of a stormwater flow channel, and an upper pipe 2 guides a water flow 3 to flow downward. The flow characteristics determine that when the water flow rate of the flow channel is less than the full load capacity, the water flow 3 is annular, leaving a central gap 4 in the flow channel. During heavy rains, the surface water flow 8 and the pipe water flow 3 merge to form a water curtain 6, which blocks the surface water flow from entering the downstream pipe 10, resulting in flooding of the surface (e.g., balcony, etc.). In addition, this water curtain 6 arranged circumferentially around the interior of the pipe also blocks the release of air 9 in the downstream pipe 10, thereby reducing the available capacity of the system, resulting in general overflow and local overflow at each inlet / outlet.

[0016] Figure 2 A manifold 5 is shown coaxially disposed within a downpipe 10 having a drainage / water inlet section 25. The water inlet section 25 may be disposed on a balcony as part of a stormwater channel for a multi-storey building. The manifold 5 may be an extension of an existing pipe or a detachable element that may be attached to an existing pipe in a stormwater channel. The manifold 5 includes an upper portion, a transition section 15, and an outlet portion, wherein the upper portion corresponds to the downpipe system. The transition section 15 is a diameter reduction section disposed in the middle for reducing the water flow from the diameter of the upper portion to the smaller diameter of the outlet portion 20. The outlet portion 20 has a pipe hole 30 through which the water flow 35 flows from the upstream 55 and eventually flows out 40. The manifold assembly also includes a modified downpipe 10, which includes a flow concentration section 25, which includes an enlarged annular flange.

[0017] When the upstream water 55 enters the transition section, the shrinking diameter of the transition section causes a small blockage 37 of the water, which causes the water to pass through the entire pipe hole, avoiding the annular flow pattern in Figure 1. When the water flow 35 passes through the transition section 15 and enters the outlet section 20, the diameter of the water flow 40 flowing out of the header 5 is smaller than the diameter of the downpipe 10, and the water flow 40 flowing out of the header 5 is concentric with the downpipe 10. The water then flows out of the outlet hole, and an annular space 45 is formed around the water flow 40. The speed and pressure of the water flow 40 increase when flowing out of the outlet hole, forming a concentric concentrated water column. As a result, the upstream water is prevented from forming an annular water flow in the downpipe 10, avoiding the water curtain shown in Figure 1. The annular space 45 allows air to flow along the fluid path from a point adjacent to the outlet hole 30 to a point 50 outside the downpipe. In this way, the air in the annular space can be released from the flow concentration section 25. In addition, surface water 47 is collected by the drainage pipe section 25 and allows the surface water 47 to flow into the downpipe 10. When the surface water 47 contacts the ground surface, it flows downward in a circular flow. When the drainage pipe section 25 receives the surface water within its capacity, the arrangement of the manifold 5 causes the surface water 47 to flow in a circular flow. Therefore, the three fluid paths (surface water 47, released air 50, and fluid 40 in the downpipe) can coexist without interfering with the flow capacity of the system.

[0018] FIG. 3A to FIG. 3C Another embodiment of a header assembly according to the present invention is shown. In this embodiment, the header 60 is a separable element that can be connected to an existing downpipe, such as being brazed, bolted, tied, clamped, screwed or welded into place. FIG. 3A to FIG. 3C The embodiment as Figure 2 A comparison with the embodiment of FIG. 1 shows a header 60 including a transition portion and an outlet portion.

[0019] In the above embodiment, the manifold 60 includes a profiled outlet portion 70 having a recessed portion 75 disposed on the circumference of the manifold 60, the recessed portion 75 not only serves as a diameter of the transition water flow, but also provides a profile for the water flow to limit it to the central axis of the fluid concentration pipe section 65. Therefore, water flows from the outlet hole 90 into the downpipe 65, forming an annular space 95. It should be noted that the drainage pipe section 85 is similar to Figure 2 Drain pipe section 25. It can be understood that, by applying the concentrator provided by the present invention, drain pipes of different structures can operate in the same way to achieve the above three fluid paths.

[0020] The relationship between the diameter of the downpipe and the outlet orifice may be a function of a number of parameters, including flow rate, downpipe length, height of the downpipe above the header, and secondary factors that affect these parameters, such as the size and number of upper and lower branches of the header assemblies 60, 65. Thus, at very high flow rates, the outlet orifice diameter may be 50% to 90% of the downpipe diameter in order to create sufficient annular space to effectively release air.

[0021] Figure 4 Various embodiments of the shape of the manifold outlet hole are shown. Four outlet holes of shapes 125 to 140 are provided, wherein the cross-sections of the various outlet holes are 105 to 120. It is understood that the applicable shapes of the present invention may exceed Figure 4 The range of shapes shown, Figure 4 Possible shapes of headers are shown, but not all shapes. Other shapes, such as cylindrical, where the converging pipes are reduced to create pressure to expel water upstream, thereby allowing air to escape and water to enter the system, will also fall within the scope of the present invention.

[0022] The first part 105 is a cross section of the header, the second part 110 is a plan view of the header assembly, the third part 115 is a downpipe, and the last part is a cross section of the outlet opening of the header.

[0023] Each of the shapes shown is a concave polygon with three or more degrees of rotational symmetry. It will be appreciated that shapes with one or two degrees of rotational symmetry are possible in order to achieve concentric water flow. The concave portion of the header is used to help the flow transition from the upper downpipe diameter to the outlet orifice diameter. The octagonal 135 and hexagonal 140 convex polygons simulate a more rounded outlet flow shape, and the three-point 125 and four-point star-shaped concave polygons act as a more rigid transition. Compared to the more open shapes 135, 140, the star-shaped orifice may require a longer transition to reduce shock losses during the transition.

[0024] In each case, while each shape may produce a different flow pattern as the water exits the header, the advantage of each shape depends on the flow rate and transition length, which can also be a function of the relationship between the aperture and header diameters.

Claims

1. A current collecting assembly for connecting to a downpipe, the current collecting assembly comprising: A header, wherein the upstream diameter of the header is equal to the diameter of the downpipe, and the outlet diameter of the header is smaller than the upstream diameter; The header is positioned in the downpipe so that the outlet hole of the outlet portion is concentric with the downpipe and the outlet hole faces downward; as well as a flow concentrating section disposed on the downpipe, the flow concentrating section enabling fluid communication between a point adjacent to the outlet opening and a point outside the downpipe; In use, water is arranged to flow through the outlet aperture, thereby forming an annular space around the water flow, allowing air in the annular space to be released along the fluid path.

2. The current collecting assembly according to claim 1, wherein: The cross-sectional shape of the outlet hole is a concave polygon.

3. The current collecting assembly according to claim 2, wherein: The concave polygon includes at least three degrees of rotational symmetry.

4. The current collecting assembly according to claim 2, wherein: The concave polygon has arc-shaped sides.

5. The current collecting assembly according to any one of claims 1 to 4, wherein: The manifold comprises a transition portion between the water drop portion and the outlet portion, and the transition portion is provided with an intermediate diameter reduction section.

6. A method for releasing air trapped in a downpipe, the method comprising the steps of: causing water to flow around the aperture of the downpipe into a header coaxially positioned to the downpipe; When the water flows through the header, the diameter of the water flow is reduced to be smaller than the diameter of the downpipe; allowing water to flow out of the concentrically disposed outlet holes of the manifold, thereby forming an annular space around the outflowing water flow; A fluid path is provided between a point adjacent the outlet aperture and a point external to the downpipe; air trapped in the annular space is thereby released along the fluid path.

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