Stormwater containment chamber and system

Abstract

The present invention relates to a plastic arch-shaped corrugated chamber for receiving and dispersing stormwater when buried beneath the surface of the earth, the chamber comprising one or more hollow stacking lugs protruding upwardly from the sidewall base flanges adjacent and in fluid communication with one or more corrugated peaks or valleys or both, wherein at least one hollow stacking lug comprises a top aperture for water to flow through.

Description

[0001] STORMWATER CONTAINMENT CHAMBER AND SYSTEM

[0002] The present invention relates to improvements in stormwater containment systems, in particular to enhancements to hydraulic efficiency of modular plastic corrugated-arch stormwater chambers.

[0003] BACKGROUND TO THE INVENTION

[0004] It is well known for attenuation systems to feature arch-shape cross-section moulded thermoplastic chambers with open bases. The chambers are buried in the ground to receive stormwater runoff from paved and roofed areas for storage and release into the local water table to replenish groundwater supply.

[0005] Such chambers are typically made by injection moulding and thermoforming. Generally, an interconnected array of chambers is laid into cavities in the ground and then covered over to create large void spaces embedded in a matrix of free-draining stone. Stormwater, such as results from rainfall, e.g., on a paved parking lot, is flowed to the end chambers via pipes. The water is detained, and over time either controllably flowed to a discharge point, and or allowed to be dispersed to the ground, soil etc.

[0006] In such systems, it is desirable to facilitate free movement of stormwater entering or exiting the system, specifically between the volume within the chambers and the stone matrix. In arched chamber systems this is generally achieved through the base of the chamber. However, as sediment carried in the stormwater may settle over time and begin to clog the base it is desirable for other water paths to be available such as to ensure sufficient water movement as not to reduce the effective capacity of the system in storm events. In prior systems, this has been achieved by incorporating vertical apertures into the side walls of the chambers. However, doing so reduces the structural performance of the walls and potentially compromises the structural capacity of the overall system.

[0007] Furthermore, to enable inexpensive and safe transportation of arched chambers, these are required to stack efficiently and safely. Usually, this involves vertical stacking, however, horizontal stacking has also been used. Nevertheless, vertical stacking is utilised in manufacturing as the chamber is not as rigid due to is still being warm from the manufacturing process. This warmth results in the need to support the base of the top arch by the arch underneath. If the base of a chamber is not supported, the chamber may flex open. Existing ways to overcome this involve a vertically orientated fin with a horizontal top surface to support the next arch.

[0008] It is therefore an object of the present invention to provide a chamber for receiving and dispersing stormwater when buried beneath the surface of the earth which overcomes the drawbacks of known solutions or at least provides a suitable alternative.

[0009] SUMMARY OF THE INVENTION

[0010] The present invention addresses the problem of facilitating the flow of water within a storm water attenuation system in a manner that does not compromise structural performance.

[0011] This problem is solved by providing the chamber with one or more hollow stacking lugs having an aperture on the top, the or each lug being located at the base of a corrugation and extending upwardly from the base flange.

[0012] The present invention relates to a chamber for receiving and dispersing stormwater when buried beneath the surface of the earth, the chamber comprising upstanding hollow stacking lugs having apertures in their tops.

[0013] The invention is set out in the claims.

[0014] Accordingly, a first aspect of the present invention is a plastic arch-shaped corrugated chamber for receiving and dispersing stormwater when buried beneath the surface of the earth, the chamber comprising: a plurality of corrugation peaks and a plurality of corrugation valleys distributed along a length of the chamber, the corrugation peaks and corrugation valleys extending transverse to a lengthwise axis of the chamber, an open base, a curved top and opposing sides running upwardly from the base to the curved top; opposing sidewall base flanges extending generally horizontally from each side of the base along the length of the chamber, wherein the chamber further comprises one or more hollow stacking lugs protruding upwardly from each sidewall base flange, each hollow stacking lug being adjacent and in fluid communication with one or more corrugated peaks or valleys or both, wherein at least one hollow stacking lug comprises a top aperture for water to flow through.

[0015] Advantageously, the hollow stacking lugs improve the structural and hydraulic performance of the chamber with the aperture in each stacking lug permitting two-way flow of water between the chamber and a surrounding stone matrix without compromising structural integrity of the chamber and limiting blockage by silt / water-borne particulate matter. This ensures water flow will still be facilitated even if there is a build-up of silt on the surface on which the chamber is placed.

[0016] The or each hollow stacking lug is open to the interior of the arch chamber.

[0017] The height of each hollow stacking lug independently is preferably in the range of from about 2% to about 10% of the height of the chamber, e.g. about 5.7%.

[0018] Advantageously, the presence of one or more hollow stacking lugs also improves packing and transport efficiency of multiple chambers, providing support for another chamber stacked on top.

[0019] The sides of the chamber may be curved or straight.

[0020] In a preferred embodiment, the or each hollow stacking lug containing a top aperture has a substantially flat, i.e., horizontal, top containing the aperture. However, this is not to be considered limiting and the top may be sloped up to about 30 degrees away from the horizontal. A larger slope than this puts too much pressure on the hollow stacking lug.

[0021] In a preferred embodiment, at least one upstanding protrusion is located adjacent the aperture on the top surface of the lug to protect the aperture from being blocked by backfill stone in use of the chamber, particularly preferably two upstanding protrusions either side of the aperture.

[0022] In a preferred embodiment, the chamber further comprises a step feature in the form of a protruding ledge part way up an arch corrugation, particularly preferably at the same location as injection ports, to increase the moment of section locally and improve shape retention during stacking and installation of the chamber.

[0023] The chamber is preferably made of injection moulded polypropylene, polyethylene, polyvinyl chloride, glass reinforced plastic or other suitable material.

[0024] A preferred chamber according to the invention may be from about 300mm to 5m wide at the base, 150mm to 5m high at the peak interior and 300mm to 12m long. The chamber within this size range may be used where there are very high inflow rates, i.e., from about 1 litre per second to 10m3per second, filling the internal voids of an inlet row quickly which requires the air in the chamber to escape quickly. Chambers with heights towards the lower end of the range are for use where there is limited depth available for the stormwater drainage system.

[0025] In another aspect, the invention provides a stormwater containment system comprising a plurality of chambers as described herein.

[0026] In this aspect, chambers are preferably installed in rows separated by backfill stone and surrounded by geotextiles. Geotextiles are filters that are known to clog with sediment over time particularly under one way flow conditions and so limit the amount of water that can escape. Geotextiles in two-way flow clog less than when in a one-way flow condition.

[0027] Preferably, the system further comprises a manhole that extends to the surface to enable cleaning from the surface, e.g., by self-propelled jetting units used in conjunction with a vacuum truck.

[0028] The horizontal positioning of the apertures on the stacking lugs results in any geotextile placed over the aperture being in a two-way flow condition with the initial flows being upflows. Additionally, this location does not detract from structural requirements.

[0029] Advantageously, the apertures enable a larger amount of inflow to the chamber to escape such that less pipework is required to cope with the inlet flow.

[0030] The skilled person will understand that where the same feature has been referenced in different aspects of the invention, this feature comprises the same parts and operates in the same way unless otherwise stated. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Two preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0032] Figure 1 is a perspective view of a first embodiment of a large chamber according to the invention for receiving and dispersing stormwater;

[0033] Figure 2 is a side view of the chamber of Figure 1 ;

[0034] Figure 3 is an end view of the chamber of Figure 1 ;

[0035] Figure 4 is an enlarged perspective view of detail 01 in Figure 3;

[0036] Figure 5 is a plan view of the chamber of Figure 1 ;

[0037] Figure 6 is a cross-sectional side view of the chamber of Figure 1 ;

[0038] Figure 7 is an enlarged underneath perspective view of detail 02 in Figures 5 and 6;

[0039] Figure 8 is a cross-sectional view of a corner detail of two chambers of Figure 1 stacked on one another;

[0040] Figure 9 is a perspective view of a second embodiment of a smaller chamber according to the invention for receiving and dispersing stormwater;

[0041] Figure 10 is a side view of the chamber of Figure 9;

[0042] Figure 11 is an end view of the chamber of Figure 9;

[0043] Figure 12 is an enlarged perspective view of detail 03 in Figure 11 ;

[0044] Figure 13 is a plan view of the chamber of Figure 9;

[0045] Figure 14 is a cross-sectional side view of the chamber of Figure 9; Figure 15 is an enlarged underneath perspective view of detail 04 in Figure 14; and

[0046] Figure 16 is a cross-sectional view of a corner detail of two chambers of Figure 9 stacked on one another.

[0047] DETAILED DESCRIPTION

[0048] In overview, a corrugated upflow chamber for receiving and dispersing stormwater is provided, the chamber comprising hollow stacking lugs at the base of one or more corrugations, the lugs having a top aperture for flow of water therethrough.

[0049] Two embodiments of the present invention will be described in detail with reference to the drawings, where like reference numerals represent like parts and assemblies throughout the several views.

[0050] It will be appreciated that the invention should not be construed to be limited to the examples, which are now described; rather, the invention is construed to include any and all applications provided herein and all equivalent variations within the skill of the ordinary artisan.

[0051] Referring to Figures 1 to 8 of the drawings, there is shown a chamber according to the first embodiment of the invention, generally referred to herein by reference numeral 100 and comprising an open base 110, curved sidewalls 121 , 122 which run upwardly to top 120 from opposing horizontal side base flange portions 130 bearing on soil (not shown) during use.

[0052] Chamber 100 has a plurality of corrugations 150 which run transverse to the chamber length axis. As shown in Figure 2, the corrugations comprise a plurality of peak corrugations 151 and valley corrugations 152 spaced apart along the length axis of chamber 100.

[0053] Each peak corrugation 151 is provided with stiffening buttresses 153 projecting therefrom.

[0054] Extending upwardly from base flanges 130 adjacent intermediate ribs are a multiplicity of spaced apart hollow upflow lugs 140.

[0055] Each hollow lug 140 defines an enclosed space and has a flat top 141 provided with an aperture 142 to allow upflow of water therethrough. In the preferred embodiment shown in the drawings, each upflow lug 140 is in the form of a hollow trapezoidal prism open to the interior of the chamber. However, this is not to be considered limiting and other suitable shapes for forming an effective buttress to support the upper part of chamber 100 such as cones, cuboids, triangular prisms etc., are contemplated within the scope of the invention.

[0056] Upstands 143 are located adjacent aperture 142 to prevent clogging of the aperture, e.g., by silt.

[0057] As shown in Figure 8, upflow lugs 140 help to support the base flange 130 of an overlying nested chamber 101 , to stop nested chambers 100, 101 from jamming during shipment or storage.

[0058] Using horizontal apertures 142 above base 110 of chamber 100 achieves the objective of facilitating water movement in a way that avoids both: i) potential blockage from silt / allowing silt into a surrounding stone matrix (not shown); ii) reduction in structural capacity of side walls 121 , 122.

[0059] As shown in Figure 7, the aperture 142 extends to the bottom of the flange portions 130 bifurcate lugs 145 allow easy water access into the flange portions 130.

[0060] Injection moulded products require injection ports that allow the flow of polymer in a minimum amount of time. In the preferred embodiment shown, each injection port is in the form of a truncated trapezoid to increase the moment of section at this location and to act as a buttress pushing on stone backfill to support arch 120 above the buttress level enabling arch 120 to carry more vertical load.

[0061] The dimensions of channel 100 are given by way of reference only and are not limiting in any way, the height is 1140mm and the width is 1950mm.

[0062] Referring to Figures 9 to 16, there is shown an alternative chamber according to the invention, generally referred to herein by reference numeral 200. Chamber 200 differs from chamber 100 in that it is smaller. The dimensions for reference only and are not limiting in any way and comprise 720 mm in height and 1150mm in width. Chamber 200 comprises an open base 210, curved sidewalls 221 , 222 which run upwardly to top 220 from opposing horizontal side base flange portions 230 bearing on soil (not shown) during use.

[0063] Chamber 200 has a plurality of corrugations 250 which run transverse to the chamber length axis. As shown in Figure 10, the corrugations comprise a plurality of peak corrugations 251 and valley corrugations 252 spaced apart along the length axis of chamber 200.

[0064] Each valley corrugation 252 is provided with stiffening buttresses 253 projecting therefrom.

[0065] Extending upwardly from base flanges 230 adjacent intermediate ribs are a multiplicity of spaced apart hollow upflow lugs 240.

[0066] Each hollow lug 240 defines an enclosed space and has a flat top 241 provided with an aperture 242 to allow upflow of water therethrough. In the preferred embodiment shown in the drawings, each upflow lug 240 is in the form of a hollow trapezoidal prism open to the interior of the chamber. However, this is not to be considered limiting and other suitable shapes for forming an effective buttress to support the upper part of chamber 200 such as cones, cuboids, triangular prisms etc., are contemplated within the scope of the invention.

[0067] Additionally, additional curved lugs 260 are provided in recess of 252 and have a pair of stacking pins 265 but no aperture.

[0068] It is to be understood that the invention is not limited to the specific details described herein which are given by way of example only and that various modifications and additions are possible without departing from the scope of the invention as defined in the appended claims.

Claims

9CLAIMS:1 . A plastic arch-shaped corrugated chamber for receiving and dispersing stormwater when buried beneath the surface of the earth, the chamber comprising: a plurality of corrugation peaks and a plurality of corrugation valleys distributed along a length of the chamber, the corrugation peaks and corrugation valleys extending transverse to a lengthwise axis of the chamber, an open base, a curved top and opposing sides running upwardly from the base to the curved top; and opposing sidewall base flanges extending horizontally from each side of the base along the length of the chamber, wherein the chamber further comprises one or more hollow stacking lugs protruding upwardly from each sidewall base flange, each hollow stacking lug being adjacent and in fluid communication with one or more corrugated peaks or valleys or both, wherein at least one hollow stacking lug comprises a top aperture for water to flow through.

2. The chamber as claimed in claim 1 , wherein the or each hollow stacking lug comprising a top aperture independently has a substantially flat top containing the aperture.

3. The chamber as claimed in claim 1 or claim 2, wherein the or each stacking lug comprising a top aperture independently further comprises one or more upstands adjacent the top aperture to prevent clogging of the aperture.

4. The chamber as claimed in any one of the preceding claims, wherein the chamber has straight sides.

5. The chamber as claimed in any one of claims 1 to 3, wherein the chamber cross section is continuously curved.

6. The chamber as claimed in any one of the preceding claims, wherein the chamber comprises a first plurality of hollow stacking lugs protruding upwardly from the sidewall base flanges, wherein each lug of said first plurality indepedently comprises a top aperture for water to flow through.

7. The chamber as claimed in claim 6, wherein the chamber further comprises a second plurality of hollow stacking lugs protruding upwardly from the sidewall base flanges, wherein each lug of said first plurality indepedently comprises an upwardly protruding stacking pin.

8. The chamber as claimed in any one of the preceding claims, wherein the chamber further comprises a step feature in the form of a protruding ledge partway up a peak or valley corrugation to increase the moment of section locally and improve shape retention during stacking and installation of the chamber.

9. The chamber as claimed in claim 8, wherein the protruding ledge is in the form of a truncated trapezoid and comprises an injection port.

10. A stormwater containment system comprising a plurality of chambers as claimed in any one of claims 1 to 9 interconnected in serial fashion to form a string of chambers.

11. The stormwater containment system as claimed in claim 10, wherein the system further comprises an end cap at each end, each end cap being provided with at least one hollow stacking lug comprising a top aperture for water to flow through.

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