In a further aspect of the invention said buoyant walls partially submerged in a fluid, located inside said channel, raise due to vertical hydrostatic forces as pressure acting below said wall are greater than the atmospheric forces acting above. The buoyant force has a magnitude equal and opposite to the weight of fluid displaced by said wall. Said channel would usually be positioned underground and able to receive surface fluid flows.

In a further aspect of the invention said wall with an unstable equilibrium centroid of displacement volume rotates the top of said wall towards contained fluid flows. The rotating wall equilibrium offsets vertical buoyant forces against horizontal hydrostatic forces from contained fluids on a pivot seal.

In a further aspect of the invention the rotating wall equilibrium is positioned on said pivot seal with a guide bracket which compresses said seal into a counter lever support frame. Vertical partitions in said wall create a bending moment shorter than that of a horizontal continuous beam reducing the deflection forces acting on said wall by the contained hydrostatic loads.

In a further aspect of the invention no components are required on the upstream side of said wall which can facilitate ground level open grates, filtration screens or baskets and convenient access of said seals for maintenance.

In a further aspect of the invention said buoyant wall will rise before the water level reaches said seals thereby keep maintenance requirements to a minimum and ensuring optimal operation.

In a further aspect of the invention said channel can be drained by a float activated pump, self-siphon with air break release valve or at grade to a downstream pipe network using a one way non return valve.

In a further aspect of the invention a vertical seal is located on each end of said wall where hydrostatic pressure is applied by the contained fluid against a vertical frame mounted on boundary retaining walls. In a further aspect of the invention tension brackets are mounted on said boundary walls to prevent wave action from removing pressure from said vertical wall seal.

Embodiments of the invention will now be described in further detail with reference to, and as illustrated in the accompanying figures. These embodiments are illustrative and not intended to be restrictive of the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG .1 depicts a perspective top view of a partial breakaway of an embodiment of the hydrostatic fluid containment system in place between the boundary wall flow interception zone of an underground car park and in the open resting state.

FIG .2 depicts a perspective top view of a partial breakaway of an embodiment of the hydrostatic fluid containment system in place between the boundary wall flow interception zone of an underground car park and in the closed resting state. FIG .3 depicts a cross section of the buoyant wall chamber in the open resting state.

FIG .4 depicts a cross section of the buoyant wall chamber in the partial open state.

FIG .5 depicts a cross section of the buoyant wall chamber in the closed state. FIG .6 depicts a cross section of the buoyant wall chamber in the closed state including boundary wall and pump isolated.

FIG .7 depicts a cross section of the buoyant wall chamber in the closed state including boundary wall and pump in operation.

FIG .8 depicts a cross section of the buoyant wall chamber in the closed state including boundary wall, pump and self-siphon in operation.

FIG .9 depicts a cross section of the buoyant wall chamber in the closed state including boundary wall and gravity discharge in operation.

FIG .10 depicts a cross section of the buoyant wall chamber in the open resting state with filtration screen.

FIG .11 depicts a cross section of the buoyant wall chamber in the open resting state with filtration basket.

FIG .12 depicts a cross section of the buoyant wall chamber in the open resting state including boundary wall and freestanding installation. FIG. 1 depicts the hydrostatic fluid containment system apparatus 10 in the lowered open state constructed of impervious material such as concrete, steel or plastic. In this form the embodiment of the invention is located between boundary wall openings 11 in which rising water flows are to be intercepted from the upstream road, path or waterway 12 from entering the downstream dry zone 13. The buoyant wall 14 is in the open resting state where nearby water levels are below the removable inlet grates 15 and both vehicle and pedestrian traffic are unobstructed. Chamber 16 contains an angled bracket seal 17 connected to pivot seal 18 and pivot seal 18 connected to chamber wall 16 both constructed preferably from stainless steel or similar corrosive resistant material. The pivot seal 18 is used for sealing the buoyant wall in the horizontal and vertical direction. Buoyant wall 14 is fixed to a support beam 19 which displace top loads from traffic across the apparatus 10 and prevents vertical forces from being applied to buoyant wall 14 when in the lowered open position. Support beam 19 also restricts horizontal deflection loads applied by the contained fluid from deforming buoyant wall 14 when in the raised closed position. Buoyant wall base 20 is wider than buoyant wall 14 which facilitates pivot sealing guide 21 to align with angle seal bracket 17 and provides a seating bed for sealing rubber or appropriate flexible material 22 which will also align with pivot seal 18 when in the raised closed position. Buoyant base 20 dimensions can be calibrated to ensure equal and opposite mass displacement in order to raise varying height buoyant walls 14. Sealing rubber 22 is attached to the downstream side of buoyant wall 14 in both horizontal and vertical faces of buoyant wall 14 to create a watertight seal on against pivot seal 18 in both horizontal and vertical directions. Wave tension brackets 23 and guide wall frame 24 are connected to boundary wall 11 which guide buoyant wall 14 when raising into the closed position. Hydrostatic forces imposed on buoyant wall 14 from the contained fluids in the upstream catchment zone 12 create a water sight seal when sealing rubber 22 is compressed against guide wall frame 24 when in the raised closed position. Wave tension brackets 23 compress buoyant wall 14 against wall frame 24 when in the upright closed position which create a watertight join on sealing rubber 22 to prevent fluid from entering downstream dry zone 13. Wave tension brackets 23 prevent waves on the upstream catchment side 12 from creating negative hydrostatic forces on buoyant wall 14 which may break the watertight connection on sealing rubbers 22. A float activated pump 25 transmits fluid from collection sump 26 to discharge drain 27 which can be directed back to the road, path or waterway 12 either upstream or downstream of apparatus 10. Float activated pump 25 ensures buoyant wall 14 rests at the bottom of chamber 16 when in the open state such as when the fluid levels to be contained subside or if small spills are intercepted. Float activation pump 25 prevents buoyant wall 14 from resting in the half open/closed state if incoming intercepted flows are less than the pump can displace from collection sump 26. Buoyant wall 14 comprises of vertical partitions 28 which act as vertical support beams to reduce vertical and horizontal bending moments on buoyant wall 14 applied from the contained hydrostatic forces in upstream catchment 12. Pivot sealing guide 21 and angled bracket seal 17 create a fixed point to which vertical partitions 28 are attached when buoyant wall 14 is in the raised closed position to prevent deflection of buoyant wall 14 as explained with more detail later in the specification. Angled bracket seal 17 and pivot sealing guide 21 could be constructed in a continuous section or in shorter individual modules spaced along the length of buoyant wall 14. Pivot seal 18 is connected to chamber 16 with fasteners 29 and angled bracket seal 17 is connected to pivot seal 18 with fasteners 30 which can be removed to access buoyant wall 14 and associated components during service or maintenance. Angled bracket seal 17 can be adjusted to obtain watertight alignment between pivot seal 18 sealing rubber 22 and buoyant wall 14.

FIG. 2 depicts the hydrostatic fluid containment system apparatus 10 in the open closed state described with greater detail later in the specification (water level not shown in FIG. 2 but depicted in FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8 and FIG. 9). Fluid enters inlet grate 15 from upstream road, path or waterway 12 and settles in collection sump 26 where the fluid level rises in chamber 16 causing the buoyant wall base 20 to raise buoyant wall 14. As buoyant wall 14 raises it is positioned by pivot seal guide 21 and wall frame 24 until it reaches the angled seal bracket 17, sealing rubber 22 and pivot seal 18. Wave tension brackets 23 compress buoyant wall 14 against wall frame 24 when in the upright closed position. Vertical partitions 28 act as vertical support beams to reduce vertical and horizontal bending moments on buoyant wall 14. Pivot sealing guide 21 and angled bracket seal 17 create a fixed point to which vertical partitions 28 are attached when buoyant barrier 14 is in the raised closed position. Support beam 19 restricts horizontal deflection loads applied by the contained fluid from deforming buoyant wall 14 when in the raised closed position. FIG. 3 depicts the hydrostatic fluid containment system apparatus 10 in the lowered open state where buoyant wall base 20 is located above collection sump 26 to prevent vertical compression forces acting on buoyant wall 14 applied by traffic on support beam 19. Support beam 19 displaces traffic loads across inlet 15 and pivot seal 18. Chamber 16 has an internal rebate below inlet grate 15 to allow the flow of fluids from upstream catchment 12. Sealing rubber 22 and pivot seal guides 21 are attached to buoyant wall 14. Pivot seal 18 is connected to chamber 16 with fastener 29 while angled bracket seal 17 is connected to pivot seal 18 with fastener 30 on the downstream dry zone 13.

FIG. 4 depicts the hydrostatic fluid containment system apparatus 10 in the partially raised closing state. Fluid from upstream catchment 12 has entered inlet grate 15 and started filling chamber 16. Fluid levels in collection sump 26 has risen to a point where the displacement mass of buoyant wall base 20 is greater than the total mass of buoyant wall 14. The configuration size of buoyant wall base 20 is in such a way that seal rubber 22 remains above rising fluid levels to restrict particles in suspension from being attached to rubber seal 22. Pivot sealing guide 21 follows the profile of chamber wall 16 as the unstable equilibrium centroid of displacement volume from buoyant wall base 20 rotates the top of buoyant wall 14 towards contained fluid in catchment 12. This rotation and positioning of pivot sealing guide 21 facilitates the interlocking connection between angled bracket seal 17 and pivot sealing guide 21 which ensures the correct mating of components.

FIG. 5 depicts the hydrostatic fluid containment system apparatus 10 in the raised closed state. Fluid has filled chamber 16 raising buoyant wall 14 to the fully closed position creating vertical hydrostatic forces on buoyant wall base 20 which compresses sealing rubber 22 between pivot seal 18. Pivot sealing guide 21 is connected with angle bracket seal 17 which has horizontally compressed sealing rubber 22 against pivot seal 18 due to the tapered shape of pivot sealing guide 21. Vertical forces from buoyant wall base 20 which pivot the top of buoyant wall 14 towards contained fluids on upstream catchment 12 are counteracted by horizontal hydrostatic forces from the contained fluid which pivot the top of buoyant wall 14 towards downstream dry zone 13. Vertical partitions 28 act as vertical support beams to reduce vertical and horizontal bending moments on buoyant wall 14. Pivot sealing guide 21 and angled bracket seal 17 create a fixed point to which vertical partitions 28 are attached when buoyant barrier 14 is in the raised closed position. Support beam 19 restricts horizontal deflection loads applied by the contained fluid from deforming buoyant wall 14 when in the raised closed position.

FIG. 6 depicts the hydrostatic fluid containment system apparatus 10 in the raised closed state detailing the boundary wall 11 sealing configuration. Sealing rubber 22 is compressed between buoyant wall 14 and guide wall frame 24 by horizontal hydrostatic forces from contained fluid in catchment 12. Tension brackets 23 prevent wave motion in the upstream catchment 12 from creating negative pressures on buoyant wall 14 and support bracket 19 which could allow fluid flows to the downstream dry zone 13. The float activated pump 25 non-return valve 31 on discharge drain 27 is in the closed position until the pump is activated when contained fluid in upstream catchment 12 subside.

FIG. 7 depicts the hydrostatic fluid containment system apparatus 10 in the raised closed state when contained fluid in catchment 12 has subsided. Float activated pump 25 conveys fluid through discharge drain 27 and past non-return valve 31 expelling fluid from chamber 16 to either upstream catchment 12 or downstream zone 13 depending on the existing drainage system surrounding the apparatus. Buoyant wall 14 lowers back into chamber 16 as depicted in FIG. 3 when the contained fluid is expelled by pumping means as described in FIG.7 or siphon and gravity means as described in FIG. 8 and FIG. 9 respectively.

FIG. 8 depicts the hydrostatic fluid containment system apparatus 10 in the raised closed state when contained fluid in catchment 12 has subsided. A siphon tube 32 with attached air break and isolation valve can be attached to chamber 16 where the downstream dry zone 13 is lower than upstream catchment 12 such as

underground car park installations. As fluid fills chamber 16 it also flows through siphon tube 32 which becomes self-primed by fitting an air break device and isolation valve to siphon tube 32. When the contained fluids subside at catchment 12 the isolation valve can be opened which will drain chamber 16 of fluid and lower buoyant wall 14 to its open resting state as depicted in FIG. 3.

FIG. 9 depicts the hydrostatic fluid containment system apparatus 10 in the raised closed state when contained fluid in catchment 12 has subsided. A gravity discharge drain 27 can be used to expel fluid from chamber 16 and fitted with a nonreturn valve 31 when the upstream catchment 12 fluid levels subside lower than catchment sump 26 such as a river, waterway or esplanade installation. FIG. 10 depicts the hydrostatic fluid containment system apparatus 10 in the lowered open state showing design flexibility by not requiring any support structures on the upstream catchment 12 side of the device. The internal taper on rebate chamber 16 may be increased so a filtration screen 33 can be installed to prevent water borne pollutants from entering collection sump 26.

FIG. 11 depicts the hydrostatic fluid containment system apparatus 10 in the lowered open state showing design flexibility by not requiring any support structures on the upstream catchment 12 side of the device. The distance between buoyant wall 14 and the internal upstream wall on Chamber 16 may be increased so a filtration basket 34 can be installed and retain large volumes of water borne pollutants from entering collection sump 26.

FIG. 12 depicts the hydrostatic fluid containment system apparatus 10 in the lowered open state showing design flexibility by not requiring any support structures on the upstream catchment 12 side of the device. Chamber 16 can be completely removed from the upstream side of the apparatus when installed on a river, walkway or esplanade as all of the components required for operation are mounted on the downstream dry zone 13 of the installation.

DETAILED DESCRIPTION AND BEST MODE OF IMPLEMENTATION

It is preferable that the hydrostatic fluid containment system apparatus be constructed from 150mm reinforced precast concrete fitted with lifting lugs to achieve uniform horizontal and vertical faces to enable the internal and external fabricated components of the device to be fitted to smooth surfaces of the chamber 16 and to allow for lifting, transportation and installation. Alternatively corrosion resistant steel treated metal, plastic or composite material could deliver a similar smooth surface for component precision. Chamber 16 is preferably located between smooth boundary walls 11 to facilitate watertight joins between vertical guide wall frames 24 which should be constructed from 5mm thick stainless steel angle extrusions to prevent stormwater passing between boundary walls 11 and buoyant wall 14 from reaching dry zone 13.

It is preferable that sealing rubber 22 be constructed from 25mm diameter half round hollow rubber tube with a 25mm flat continuous tag attached. The hollow tube allows for greater deformation and can seal along faces that may not be completely straight due to manufacturing or installation tolerances. The flat continuous tag facilitates a mounting compression join using flat bar that joins the sealing rubber 22 to buoyant wall 14. Pivot sealing guide 21 should be tapered at 10 degrees to allow for a smooth transition when compressing sealing rubber 22 and pivot seal 18.

Pivot seal guide 21 constructed from rigid material to prevent deformation and attached directly to vertical partitions 28 on buoyant wall 14 to enable a stable connection with limited joins between support beam 19 through to angled bracket seal 17. Pivot sealing guide 21 should have friction resistant material such at HDPE attached to the edge facing chamber 16 wall to prevent gouging. Angled bracket seal 17, pivot seal 18, support bean 19 and tension brackets constructed from 5mm thick stainless steel extrusions. Angled bracket seal 17 should have elongated holes for fasteners 30 which allows calibration to obtain a watertight seal if manufacturing tolerances are not met during construction of buoyant wall 14.

Buoyant wall 14 should be constructed from closed cell foam laminated in 2mm stainless steel metal sheet or hollow roto moulded polyethylene plastic for extra impact and corrosive resistance. Vertical partitions 28 should be 5mm thick and 100mm wide to provide sufficient rigidity and prevent deflection of buoyant wall 14.

Inlet grate 15 should withstand vehicular traffic and be removable for servicing and maintenance of chamber 16. Filtration screen 32 and basket 33 will be constructed from corrosion resistant material with aperture sizes of between 1.5 and 3mm to prevent debris from interfering with the movement of buoyant wall 14 and the water sealing rubber 22.

It is preferable that in the current configuration, buoyant wall 14 is 100mm wide while the buoyant wall base 20 is 200mm wide and 200mm deep to provide enough hydrostatic force to lift a 500mm tall buoyant wall 14. A gap between collection sump 26 and buoyant wall base 20 is required to stop compressive forces from traffic above from deforming buoyant wall 14.

Float activated pump 25 should be submersible with 32mm diameter discharge drains 27 for both pumped and siphon 32 pipes. It is preferable that float activated pump 25 has twin activation heights, initially when the collection sump 26 fluid level is just below the lifting displacement volume of buoyant wall base 20 and disengage when fluid levels are above ground surface level, then re-engage when fluid in the upstream catchment 12 subsides back to ground level. This operation will ensure buoyant wall 14 will remain below ground when small volumes of fluid enter chamber 16 and disengage pump from operating when the buoyant wall 14 is in the raised open position until upstream catchment 12 has subsided. It will be appreciated by those skilled in the art, that the invention is not restricted in its use to the particular application described, nor is it restricted to the feature of the preferred embodiment described herein. It will be appreciated that various modifications can be made without departing from the principals of the invention, therefore, the invention should be understood to include all such modifications within its scope.