Abstract:
This invention relates to an inflatable dam assembly. In particular, this invention relates to a combined inflation, sealing and anchoring arrangement for a self-supporting dam for protecting buildings and property from rising flood water. An inflatable dam assembly comprises an inflatable membrane; means for inflating said membrane; an anchoring element operably engaged with the inflatable membrane; and a duct for housing the anchoring element and at least a part of said membrane, the duct comprising retaining means configured to retain the anchoring element within the duct, wherein, in use, the anchoring element is moveable relative to the duct in a first direction towards the retaining means and in a second direction away from the retaining means.

Description:
BACKGROUND 
       [0001]    a. Field of the Invention 
         [0002]    This invention relates to an inflatable dam assembly. In particular, this invention relates to a combined inflation, sealing and anchoring arrangement for a self-supporting dam for protecting buildings and property from rising flood water. 
         [0003]    b. Related Art 
         [0004]    When flood water rises above normal ground level it begins to infiltrate building fabrics exploiting any weakness in/or absence of damp proofing arrangements. If the flooding below the damp proof course is sustained or rises to apertures within the building envelope severe damage to the property and its contents occurs. Severe flood water damage usually renders a property uninhabitable for long periods of time. 
         [0005]    A number of flood defense systems for buildings and other structures are known; however, many of these systems have disadvantages in relation to cost, size and the ease and speed of deployment when flooding occurs. 
         [0006]    It is, therefore, an object of the present invention to provide an inflatable dam assembly that overcomes the disadvantages of prior art systems. 
       SUMMARY OF THE INVENTION 
       [0007]    According to a first aspect of the present invention there is provided an inflatable dam assembly comprising:
       an inflatable membrane;   means for inflating said membrane;   an anchoring element operably engaged with the inflatable membrane; and   a duct for housing the anchoring element and at least a part of said membrane, the duct comprising retaining means configured to retain the anchoring element within the duct,   wherein, in use, the anchoring element is moveable relative to the duct in a first direction towards the retaining means and in a second direction away from the retaining means.       
 
         [0013]    Preferably the anchoring element is movable between a first position in which the membrane is not clamped between the anchoring element and the retaining means, such that there is a gap between the membrane and the retaining means, and a second position in which a part of the membrane is clamped between the anchoring element and the retaining means. 
         [0014]    Preferably the duct has opposing side walls and the retaining means comprises a first protrusion extending inwardly from a first one of said side walls and a second protrusion extending inwardly from a second one of said side walls. 
         [0015]    Preferably the retaining means comprises a pair of opposing first and second protrusions forming a neck region of the duct, a dimension of the neck region being smaller than a dimension of the anchoring element, such that the anchoring element cannot pass through the neck region of the duct. A lower region of the duct may, therefore, be defined between a base of the duct and the neck region, and the anchoring element may be housed within said lower region. Preferably a distance between the base of the duct and the neck region is at least two times a dimension of the anchoring element. 
         [0016]    In embodiments in which the retaining means comprises protrusions, the protrusions preferably have a substantially semi-cylindrical shape. 
         [0017]    Preferably the anchoring element is substantially cylindrical. 
         [0018]    In preferred embodiments the anchoring element is provided within the inflatable membrane. 
         [0019]    In embodiments in which the retaining means comprises protrusions, the duct preferably comprises separate first and second components, the first component including the first protrusion and the second component including the second protrusion. The first and second components are preferably secured to each other to form the duct. 
         [0020]    In preferred embodiments the inflatable dam assembly further comprises a membrane terminating element including guide means engaged with an end region of the inflatable membrane. Preferably the guide means comprises a guide rod and the end region of the inflatable membrane includes a plurality of apertures through which the rod is received. 
         [0021]    According to a second aspect of the present invention there is provided a method of installing an inflatable dam assembly, the dam assembly comprising an inflatable membrane, means for inflating said membrane, an anchoring element, and a duct having retaining means, and the method comprising the steps of:
       positioning the duct in a trench in the ground;   operably engaging the anchoring element with the inflatable membrane;   positioning the anchoring element within the duct such that the retaining means retain the anchoring element within the duct; and   connecting said inflating means to the membrane to permit inflation of the membrane,   wherein the duct is configured such that the anchoring element is moveable relative to the duct in a first direction towards the retaining means and in a second direction away from the retaining means.       
 
         [0027]    In preferred embodiments the duct has opposing side walls and the retaining means comprises opposing first and second protrusions, a first protrusion extending inwardly from a first one of said side walls and a second protrusion extending inwardly from a second one of said side walls, and the duct comprises separate first and second components, the first component including the first protrusion and the second component including the second protrusion. In these embodiments the method preferably comprises:
       inserting the first component into the trench;   positioning the anchoring element with respect to the first component;   inserting the second component into the trench, such that the first and second protrusions retain the anchoring element within the duct; and   securing the second component to the first component.       
 
         [0032]    The present invention is the key part of an impervious self-supporting dam system deployed away from any structure/site to be protected. The dam activation medium is self-contained, non-perishable and not dependant on external energy sources such as electricity which could be lost prior to flooding occurring. 
         [0033]    This invention prevents water ingress between dam and the ground by utilising a loose anchor element that wedges itself against two lower fixed points (usually below ground). As a membrane inflates it creates a seal on the inner (side to be protected) fixed point and stabilises itself against a further set of secondary upper fixed points (usually at ground level). By continuing this inner fixed point from its normal horizontal position to a vertical orientation a continuous seal can be achieved up a vertical surface from the horizontal inner fixed point below ground. 
         [0034]    As this system is self-supporting it is able to be installed away from any structure&#39;s to be protected. This ensures that natural air movement around the structure&#39;s fabric is maintained so minimising the risk of damp penetration. 
         [0035]    This invention could be activated by operating a simple hand valve or automatically triggered by a float switch arrangement or water level sensor/s detecting rising water conditions. 
         [0036]    It is possible that if chemical toilets, water storage and generator back-up were in place or temporarily available the protected building could remain habitable so that the flood situation could be monitored and the property remain secured from possible looting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    The invention will now be further described by way of example only and with reference to the accompanying drawings, in which: 
           [0038]      FIG. 1  shows an inflatable dam according to a first preferred embodiment of the present invention, and illustrates in particular the dam inflation, anchoring and sealing arrangement; 
           [0039]      FIG. 2  shows a connection between a means for inflating the dam and dam anchoring means of the inflatable dam of  FIG. 1 ; 
           [0040]      FIG. 3  shows the inflatable dam of  FIG. 1  installed in a flood defense location at a distance from a building structure; 
           [0041]      FIG. 4  shows an arrangement for terminating an inflatable membrane of an embodiment of the inflatable dam; 
           [0042]      FIGS. 5   a  to  5   c  show plan views of inflatable dams according to the present invention installed around detached, semi-detached and terraced buildings; 
           [0043]      FIG. 6  shows an inflatable dam according to a preferred embodiment of the present invention in a stowed and covered configuration below ground (solid lines) and an uncovered and deployed configuration (dashed lines); 
           [0044]      FIGS. 7 to 9  show alternative constructions of anchoring means of an inflatable dam according to embodiments of the present invention; and 
           [0045]      FIGS. 10   a  to  10   e  show stages in the method of installation of an inflatable dam according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]      FIG. 1  shows an inflatable dam  1  according to a preferred embodiment of the present invention. The inflatable dam  1  comprises a membrane  2  that, when inflated, provides a barrier to flood waters. 
         [0047]    In its inflated state an upper portion  4  of the membrane  2  is located above the level of the ground  6  and a lower portion  8  of the membrane  2  is retained below the level of the ground  6  within anchoring means  10 . The upper portion  4  of the membrane  2  has a substantially cylindrical shape when fully inflated. 
         [0048]    An anchoring and inflation assembly  12  is retained within and encapsulated by the membrane  2 . In this embodiment the anchoring and inflation assembly  12 , shown more clearly in  FIG. 2 , comprises an anchoring element  14 , an inflation manifold  16  and a means  18  for connecting the inflation manifold  16  to a source of compressed gas, for example compressed air. 
         [0049]    In this embodiment the anchoring element  14  is a substantially cylindrical tube and the inflation manifold  16 , also in the form of a substantially cylindrical tube, is positioned within the anchoring element  14 . Both the anchoring element  14  and the inflation manifold  16  include one or more holes  15 ,  17 . 
         [0050]    The anchoring means  10  comprises a duct  20  installed in the ground  6 . The duct  20  has opposing, substantially vertical side walls  22 ,  24  and a base  26 . A top of the duct  20  is open such that the duct is in the form of a substantially U-shaped channel. The duct  20  comprises retaining means or detents  28 ,  30  that extend inwardly from each of the side walls  22 ,  24 . The detents  28 ,  30 , therefore, create a narrow neck region  32  of the duct  20  and an upper chamber  34  is defined in an upper region of the duct  20  above the detents  28 ,  30  and a lower chamber  36  is defined in a lower region of the duct  20  below the detents  28 ,  30 . 
         [0051]    The duct  20  is preferably formed from two components  31 ,  33 . A main component  31  includes at least the base  26  of the duct  20 , together with one of the side walls  22  and its associated detent  28 . A second component  33  includes at least a part of the second one of the side walls  24  and the associated detent  30 . 
         [0052]    The underground duct section  20  can be readily manufactured in a wide range of materials which include, but are not limited to, Thermoplastics, Thermosetting Plastics, Aluminium, Plated Steel, Stainless Steel, Reinforced Resins and Concrete. 
         [0053]    Preferably, the main duct  20  is surrounded on either side with concrete  35  of suitable mass to serve as a robust foundation to resist the lifting and rolling forces exerted on the membrane  2  when in use, as shown most clearly in  FIG. 3 . 
         [0054]    The detents  28 ,  30  preferably comprise opposing ridges or lobes that protrude into an interior space of the duct  20 . The detents  28 ,  30  preferably have a semi-cylindrical profile and extend along the length of the duct  20 . Although the detents  28 ,  30  are described and shown in this embodiment as having a convex curved inwardly facing surface, it will be appreciated that in other embodiments the detents  28 ,  30  may be of any suitable shape for retaining the anchoring element  14  and membrane  2  as described below. 
         [0055]    The lower chamber  36  houses the anchoring and inflation assembly  12  within the lower portion  8  of the inflatable membrane  2  with the remainder of the membrane  2  being stowed in the upper chamber  34 , as illustrated most clearly in  FIG. 6 . 
         [0056]    The distance between the detents  28 ,  30 , i.e. the width of the neck region  32 , is slightly smaller than the width or diameter of the anchoring element  14 , therefore not allowing it to be pulled out of the duct  20  by membrane  2  when inflated and promoting angular contact between the anchoring element  14  and surfaces of the detents  28 ,  30  creating a wedging action. 
         [0057]    The lower chamber  36  is sized to permit vertical movement of the anchoring and inflation assembly  12 , as illustrated in  FIG. 6 . Accordingly, a height of the lower chamber  36 , i.e. the distance between the base  26  and the neck region  32  of the duct  20 , is greater than a height or diameter of the anchoring element  14 . This allows the anchoring and inflation assembly  12  to move between a first position in which the anchoring element  14  is spaced away from the detents  28 ,  30  and there is a gap between the membrane  2  and at least one of the detents  28 ,  30 , and a second position in which the anchoring element  14  clamps or seals the membrane  2  against the detents  28 ,  30 , as explained further below. Preferably the height of the lower chamber  36  is at least two times the diameter of the anchoring element  14 , but the height of the lower chamber  36  may be between 150% and 300% of the diameter of the anchoring element  14 . 
         [0058]    One advantage of the anchoring and inflation assembly  12  being significantly smaller than the lower chamber  36  of the duct  20  it is placed in, is that there is little risk of the membrane  2  being damaged during installation of the inflatable dam  1 . Accordingly, installation is a task that can be undertaken without any specialist training. 
         [0059]    A second advantage is that it allows the anchoring element  14  to be seated on the base  26  of the lower chamber  36  of the duct  20  when the membrane is in a stowed, or non-deployed, position, thereby allowing any rainfall to wash any accumulated sediment past the detents  28 ,  30  when the dam  1  is not in use. Furthermore, when the membrane  2  is deployed and inflated, the detents  28 ,  30  are wiped clean as the membrane  2  inflates and rises into position. 
         [0060]    Although anchoring element  14  and detents  28 ,  30  are depicted as rounded in shape, other geometries could also be used, including but not limited to, triangular, pentagon, hexagon, heptagon, octagon etc. or combinations of other geometries and rounded forms. 
         [0061]    One advantage of having a wedging action with the anchoring element  14  pushing against the matching profiles of the detents  28 ,  30  is that it puts the material of the two components  31 ,  33  of the underground duct  20  (restrained by its concrete surround  35 ) in compression rather than in shear allowing the duct  20  to be more compact, i.e. less material is used in the duct and the duct is easier to handle and to transport to site. 
         [0062]    Another advantage of having a wedging action coupled with small contact areas in this way is that a high compressive force can be applied across the sealing point allowing it to accommodate imperfections in the mating surface of the ridge profile  28 ,  30  of the underground duct  20 , i.e. the surface of the detents  28 ,  30  against which the membrane  2  is clamped by the anchoring element  14 . 
         [0063]    As membrane  2  inflates it sandwiches itself between anchoring element  14  and both matching ridges  28 ,  30  creating a continuous compression seal at least on the fixed ridged profile  28 . In other words, a part of the membrane is clamped between the anchoring element  14  and both matching ridges  28 ,  30 . This arrangement of having a single sealing surface and allowing the lower chamber  36  to fill with water when in use has the advantage of not having to seal any part of the secondary removable component  33  to the main component  31 . In this way, only one side of each end of main duct section needs a seal/gasket, the side incorporating the fixed prominent ridge  28 . This could be a gasket strip or a bead of flexible sealant/chemically hardened compound placed vertically from top to bottom which is simply trimmed flush with fixed prominent ridge  28  before membrane  2  and the secondary component  33  is installed. It is also possible to cast the main component  31  of the underground duct  20  with in-situ concrete using two part formers and a continuous pour technique thus eliminating the need for gaskets/sealants. 
         [0064]    A second pair of prominent ridges/radius corners  38 ,  40  located at an upper end of each of the side walls  22 ,  24 , stabilise the inflated membrane  2  from rolling when subjected to water pressure on one side, due to flood waters. The inflation pressure of the membrane  2  can be up to 8 bar above atmospheric pressure which means it can resist side pressure in a similar way a motor vehicle tyre does when cornering. Therefore, this arrangement requires no additional support to be added in order to resist imposed side movement of the membrane  2  when inflated. 
         [0065]    The materials of which the membrane  2  can made include but are not limited to Kevlar Cloth and Polyaramid Cord impregnated with Vulcanized Neoprene Rubber. 
         [0066]    The membrane  2  is inflated via the perforated, semi-rigid anchoring element  14  and the inflation manifold  16  by a flexible hose  42  within a conduit  44  connected to one or more remote gas cylinders  46  or a compressor backed-up by one or more gas cylinders (shown in  FIG. 3 ). Manifold  16  also serves as a clamping nut into which a proprietary gas connection may be screwed, using the membrane  2  as a gasket seal between the anchoring element  14  and the gas connection assembly. 
         [0067]    The materials from which the anchoring element  14  can be made include, but are not limited to, Polypropylene, Polythene and Nylon. The materials from which the inflation manifold  16  can be made include, but are not limited to, Stainless Steel, Plated Steel, Thermoplastics materials, Brass, Aluminium Bronze and Copper. 
         [0068]    All drains serving a protected building  3  would be fitted with proprietary non-return type flood protection devices and down pipes from guttering would be temporarily diverted to flow over the inflatable dam  1  to cope with rain fall-off from the roof/s. It is inevitable that some storm water will collect between the dam  1  and the building  3  due to continued rainfall, water lapping over the dam  1  from bow waves of passing rescue vehicles/boats or prolonged seepage under the dam  1  etc. It would, therefore, be preferable to install a proprietary drive channel drain system  48  connected to a sump and pump arrangement to ensure the protection of a building  3  is maintained over longer periods of flooding. 
         [0069]    Where there is a need for the inflatable membrane  2  to be attached to a structure/s, a membrane terminating element  50  is used. The membrane terminating element  50  comprises a vertically extending protrusion  52  having a profile or shape substantially the same as the horizontally extending detent  28 . This vertical section  52  having a prominent ridge profile extends upwards to above the height of the inflated membrane  2 , as illustrated in  FIG. 4 . 
         [0070]    This vertical profile element  52  works in a similar way to the underground duct arrangement  20  where membrane  2  is sealed against the prominent ridge profile  52 , but instead of being anchored by an anchoring element, a vertical pre-tensioned rod or pole  54  is used. This vertical rod or pole  54  being in tension resists horizontal forces applied when in use. Sealed end portions  56  of the membrane  2  are perforated with slots or holes  58  through which the rod or pole  54  extends. The slots or holes  58  are arranged to allow the sealed end portion  56  to rise vertically up the retaining rod or pole  54  when the membrane  2  is inflated from a stowed position underground. 
         [0071]    The materials from which the vertical profile element  52  can be made include, but are not limited to, Stainless Steel, Plated Steel and Concrete. The materials from which the vertical rod or pole  54  can be made include, but are not limited to, Stainless Steel, Plated Steel, Brass and Aluminium Bronze. 
         [0072]    This vertical profile termination arrangement  50  has the advantage that it can be secured to the side of any structure such as a bridge over a river or an existing sea/harbour wall. 
         [0073]    Furthermore, two vertical profile elements  52  bolted or otherwise secured together in a back to back arrangement (not shown) can allow two membranes  2  to be connected together making it possible for membranes  2  of different heights or materials/duty and/or inflation pressures to be used in combination in a membrane run to protect a particular structure or dwelling. This back to back arrangement has the particular advantage of allowing a section or sections of a membrane run to be deflated in order to allow flood control by purposely creating a flood plain upstream of any section under threat of being breached or structure such as a bridge being overwhelmed or damaged. 
         [0074]    Another less obvious advantage of using this back to back arrangement is to create an exact demarcation boundary point between areas of responsibility e.g. between Local Governments or Public to Private or Military/Defense installations. 
         [0075]    Groups of buildings such as housing estates or villages may have a continuous membrane run across the low lying areas prone to flooding and running up to higher ground, stopping in a simple sealed end/terminating arrangement, such as that described above. Alternatively, whole communities may be encircled by a continuous membrane. 
         [0076]    Detached buildings  60  may have a continuous dam  1  extending around the external walls with one single, joint  62  in the membrane  2 , preferably located on a straight run, as illustrated in  FIG. 5   a . Alternatively, overhead services could be disconnected and an already completed, continuous membrane  2  lifted over the building  60  and overhead services reconnected. 
         [0077]    Semi-detached and terraced buildings  64 ,  66  or obstructing structures require the internal fixed prominent ridge  28  to be continued from its underground position up the structure&#39;s vertical surface by means of a vertical profile element  52  within the termination arrangement  50 . 
         [0078]    The membrane  2  when in the stowed position is preferably covered with a non-perishable loose fitting cover  68  which is displaced during inflation, as shown in  FIG. 6 . This cover  68  can be simply laid in the underground duct  20  or tethered to it. The cover  68  may be seated on the radius corners  38  at the top of the duct side walls  22 ,  24 . The materials used for the manufacture of this cover  68  include, but are not limited to, Cast Iron, Plated Steel, Stainless Steel, Aluminium, Reinforced Resins, Thermoplastics materials and Concrete. 
         [0079]    In  FIGS. 1 to 8 , the duct  20  has been depicted as comprising an extruded profile. In particular the main component  31  of the duct  20  comprises a first extruded profile including the base  26 , side walls  22 ,  24  and detent  28 . The second component  33  comprises an extruded profile that includes the second detent  30 , and at least a part of the second component  33  has a shape that matches the profile of a part of the second side wall  24 . In this way, the second component  33  may be secured to the main component  31  by means of bolts or other suitable fixing means such that a part of the second component  33  is in contact with a part of the side wall  24  of the main component  31 . 
         [0080]    It will be appreciated, however, that many other methods of construction could be used to form the duct  20 . Examples of some other methods of production for the underground duct are illustrated in  FIGS. 7 to 9 .  FIG. 7  shows a main component  131  and a second component  133  of duct  120  that have been formed by moulding.  FIG. 8  shows an embodiment of a duct  220  in which the base  226 , side wall  222  and first detent  228  are formed by surfaces of a first region  221  of cast material, for example cast concrete. The second side wall  224  and second detent  230  are formed by surfaces of a second region or block  223  of cast material, for example cast concrete. In this embodiment the second block  223  is received within a channel  225  formed in the base  226  of the first region  221  of cast material.  FIG. 9  shows a further embodiment of a duct  320  in which the main component  331  and second component  333  are extruded. Combinations of different materials may be used for the main component  31 ,  131 ,  221 ,  331  and the removable component  33 ,  133 ,  223 ,  333  of the underground duct  20 ,  120 ,  220 ,  320 . 
         [0081]    To install the inflatable dam assembly  1  of the present invention, first the main component  31  of the two part underground duct  20  is installed in the ground  4 . 
         [0082]    The main component  31  of the duct  20  incorporating fixed detent or prominent ridge  28  is preferably laid within a simple trench on a bed of concrete with its uppermost surfaces flush with the ground level and fixed detent or prominent ridge  28  orientated toward the buildings/site to be protected by the inflatable dam  1 . The continuous cylindrical membrane  2  encasing the anchoring element  14  is then loosely placed within the main component  31  of the duct  20 , with the anchoring element  14  below the detent  28 . The second removable component  33  of the underground duct  20  having the matching detent or ridged element  30  is then secured into position, thereby forming the upper and lower chambers  34 ,  36  within the duct  20 . 
         [0083]    The method of installation of an inflatable dam assembly according to the present invention will now be described in more detail with reference to  FIGS. 10   a  to  10   e.    
         [0084]    In Stage  1  both components  31 ,  33  of the two part duct section  20  are bedded on a layer of concrete  70  within a trench  72  in the ground  4  so that the tops of its side walls  22 ,  24  are flush with the surrounding ground level. The first section of duct  20  is placed over a conduit run  44  so as to allow the flexible inflation hose to pass through. Each subsequent section of duct  20  is aligned with each other so that detent or prominent ridge  28  forms a continuous sealing surface along all sections installed. To assist in this alignment an optional guide assembly  74  comprising two wedge-shaped components  76  bolted or otherwise secured together may be used. The guide assembly is located such that the two wedge-shaped components straddle the detents or prominent ridges  28 ,  30 , as illustrated most clearly in  FIG. 10   b.    
         [0085]    In Stage  2  of the installation, spaces  78  between each side wall  22 ,  24  of the underground duct  20  and respective side walls of the trench  72  are filled with concrete, until a top surface of the concrete is flush with the ground level. In some embodiments it may be desirable if the top surface of the concrete is slightly lower than the surrounding ground level. This would allow a more aesthetic finish to be applied such as block paving, tarmac, shingle or grass. 
         [0086]    In Stage  3 , when the concrete laid in Stages  1  and  2  is sufficiently cured or hardened, the removable component  33  incorporating detent or prominent ridge  30  is removed. The inflation hose  42  is connected to the inflation manifold  16 , and therefore to membrane  2  and anchoring element  14 . The inflation hose  42  is then fed through conduit  44  until the anchoring element  14  within a part of the membrane  2  is resting on the base  26  of the underground duct  20 , as shown in  FIG. 10   c . The majority of the membrane  2  is laid at ground level above prominent ridge profile  28  in order to allow maximum access to the duct wall  24  opposite the prominent ridge  28 . 
         [0087]    In Stage  4  the removable component  33  of the underground duct  20  incorporating prominent ridge profile  30  is secured in place, as illustrated in  FIG. 10   d . At this point the membrane  2  can be inflated and inspected and/or tested. 
         [0088]    In Stage  5  the membrane  2  is folded or rolled and stowed within the underground duct  20  and enclosed by the loose fitting cover section  68 .