Hydrostatic fluid containment system

A hydrostatic fluid containment system, or flood barrier, that is positioned underground in its open state consisting of a buoyant wall which floats up and above ground level when submerged in a fluid, creating a seal from both buoyant vertical and hydrostatic horizontal forces on the containment wall imposed by the contained fluid. The system will not open prematurely and restrict access of vehicles or pedestrians until containment is necessary. The system comprises a pivot seal which seals the barrier on the upstream side, as well as another sealing element that is positioned between the pivot seal and the buoyant wall. The pivot helps to tilt the barrier towards the upstream direction.

BACKGROUND OF THE INVENTION

Loss of income due to business closure, increased insurance premiums and decreased property values may be experienced after significant fluid damage such as tidal surges, stormwater runoff, burst water pipes or industrial spills. In events such as these members of the community are often left unprepared and under resourced.

Repair and replacement cost to property and infrastructure can be significant if effected by fluid damage during floods or industrial accidents. The time taken to clean up fluid damage may be increased due to access restrictions of property, equipment and machinery.

Permanent conventional flood barriers can restrict the movement of vehicles and pedestrians while temporary barriers such as sand bags and demountable walls may be in limited supply or difficult to access during emergencies.

In one example of a floating barrier a combination service and entry pit receives floodwater from a river or ground surface area. The floodwater gradually fills the service pit until the water is just below ground level then a riser pipe allows the flow to pass down the pipe and along an underground piping network that directs the floodwater to the base of channels that contain floating barriers. The barriers float up and above ground when enough water is received however this action occurs before floodwater is actually flowing across the ground surface thereby restricting vehicles and pedestrian traffic where they would normally be trying to get to a safe location before the actual flood water became a real risk.

Fluid containment systems can be installed at and not limited to river banks, esplanades, property boundaries, underground car park access points, infrastructure access points and agricultural flow channels.

Fluids entering a channel containing a floating barrier at ground level ensure the wall will only raise when fluids are flowing across the ground surface. Fluids entering a channel below the ground surface would raise a wall before surface fluid flows are encountered. Fluids raising a wall before surface fluid flows are encountered create an unnecessary restriction above ground level. Walls raising above ground level when surface fluid flows are not encountered restrict movement of pedestrians and vehicles.

Some of the less than desirable features of floating barriers include:

Fluid entry points below ground level which float the barrier before surface flows are a threat.

Even with risers inside of entry pits, the barriers still float before surfaces flows are actually at ground level which restricts vehicle and pedestrian traffic.

Fluid entry points below ground and connected directly to stormwater drainage networks will raise prematurely as the piping pressurizes under normal design flow.

Service and flow entry pits located away from the fluid interception zone therefore unable to intercept a point source.

Piping that transfers fluid from entry pits to interception channels interfere with existing underground services.

Entry pits require large areas of sealed surfaces to be removed and regraded to divert fluid flow.

Interconnecting pipework from entry pits to interception channels require deep trenching through existing sealed surfaces.

Support blocks which create pressure for the sealing mechanism are on the upstream flow side preventing entry grates to be installed at ground level in the channel interception zone.

Support blocks restrict access to the barrier during maintenance.

Guide frames for barrier seals interfere with barrier removal and require multiple calibrations points.

Guide frames don't apply even pressure across the length of the barrier seal.

Support blocks and pipe risers in entry pits restrict the ability to install filtration screens. Long continuous barriers deflect when tall and deep installations are required.

Barriers that retract horizontally into the ground can be damaged by vehicle traffic passing above.

These and other problems are reduced or eliminated by the invention disclosed herein.

SUMMARY OF THE INVENTION

In its broadest form a hydrostatic fluid containment system ensure upstream fluids flowing across the ground surface will be intercepted by a channel where vertical buoyant fluid forces act on a submerged wall raising it out of said channel restricting fluid flow and hydrostatic fluid forces from passing downstream beyond said channel.

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.

FIG. 1depicts the hydrostatic fluid containment system apparatus10in 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 openings11in which rising water flows are to be intercepted from the upstream road, path or waterway12from entering the downstream dry zone13. The buoyant wall14is in the open resting state where nearby water levels are below the removable inlet grates15and both vehicle and pedestrian traffic are unobstructed. Chamber16contains an angled bracket seal17connected to pivot seal18and pivot seal18connected to chamber wall16both constructed preferably from stainless steel or similar corrosive resistant material. The pivot seal18is used for sealing the buoyant wall in the horizontal and vertical direction. Buoyant wall14is fixed to a support beam19which displace top loads from traffic across the apparatus10and prevents vertical forces from being applied to buoyant wall14when in the lowered open position. Support beam19also restricts horizontal deflection loads applied by the contained fluid from deforming buoyant wall14when in the raised closed position. Buoyant wall base20is wider than buoyant wall14which facilitates pivot sealing guide21to align with angle seal bracket17and provides a seating bed for sealing rubber or appropriate flexible material22which will also align with pivot seal18when in the raised closed position. Buoyant base20dimensions can be calibrated to ensure equal and opposite mass displacement in order to raise varying height buoyant walls14. Sealing rubber (or sealing element)22is attached to the downstream side of buoyant wall14in both horizontal and vertical faces of buoyant wall14to create a watertight seal on against pivot seal18in both horizontal and vertical directions. Wave tension brackets23and guide wall frame24are connected to boundary wall11which guide buoyant wall14when raising into the closed position. Hydrostatic forces imposed on buoyant wall14from the contained fluids in the upstream catchment zone12create a water sight seal when sealing rubber22is compressed against guide wall frame24when in the raised closed position. Wave tension brackets23compress buoyant wall14against wall frame24when in the upright closed position which create a watertight join on sealing rubber22to prevent fluid from entering downstream dry zone13. Wave tension brackets23prevent waves on the upstream catchment side12from creating negative hydrostatic forces on buoyant wall14which may break the watertight connection on sealing rubbers22. A float activated pump25transmits fluid from collection sump26to discharge drain27which can be directed back to the road, path or waterway12either upstream or downstream of apparatus10. Float activated pump25ensures buoyant wall14rests at the bottom of chamber16when in the open state such as when the fluid levels to be contained subside or if small spills are intercepted. Float activation pump25prevents buoyant wall14from resting in the half open/closed state if incoming intercepted flows are less than the pump can displace from collection sump26. Buoyant wall14comprises of vertical partitions28which act as vertical support beams to reduce vertical and horizontal bending moments on buoyant wall14applied from the contained hydrostatic forces in upstream catchment12. Pivot sealing guide21and angled bracket seal17create a fixed point to which vertical partitions28are attached when buoyant wall14is in the raised closed position to prevent deflection of buoyant wall14as explained with more detail later in the specification. Angled bracket seal17and pivot sealing guide21could be constructed in a continuous section or in shorter individual modules spaced along the length of buoyant wall14. Pivot seal18is connected to chamber16with fasteners29and angled bracket seal17is connected to pivot seal18with fasteners30which can be removed to access buoyant wall14and associated components during service or maintenance. Angled bracket seal17can be adjusted to obtain watertight alignment between pivot seal18sealing rubber22and buoyant wall14.

FIG. 2depicts the hydrostatic fluid containment system apparatus10in the open closed state described with greater detail later in the specification (water level not shown inFIG. 2but depicted inFIG. 4,FIG. 5,FIG. 6,FIG. 7,FIG. 8andFIG. 9). Fluid enters inlet grate15from upstream road, path or waterway12and settles in collection sump26where the fluid level rises in chamber16causing the buoyant wall base20to raise buoyant wall14. As buoyant wall14raises it is positioned by pivot seal guide21and wall frame24until it reaches the angled seal bracket17, sealing rubber22and pivot seal18. Wave tension brackets23compress buoyant wall14against wall frame24when in the upright closed position. Vertical partitions28act as vertical support beams to reduce vertical and horizontal bending moments on buoyant wall14. Pivot sealing guide21and angled bracket seal17create a fixed point to which vertical partitions28are attached when buoyant barrier14is in the raised closed position. Support beam19restricts horizontal deflection loads applied by the contained fluid from deforming buoyant wall14when in the raised closed position.

FIG. 3depicts the hydrostatic fluid containment system apparatus10in the lowered open state where buoyant wall base20is located above collection sump26to prevent vertical compression forces acting on buoyant wall14applied by traffic on support beam19. Support beam19displaces traffic loads across inlet15and pivot seal18. Chamber16has an internal rebate below inlet grate15to allow the flow of fluids from upstream catchment12. Sealing rubber22and pivot seal guides21are attached to buoyant wall14. Pivot seal18is connected to chamber16with fastener29while angled bracket seal17is connected to pivot seal18with fastener30on the downstream dry zone13.

FIG. 4depicts the hydrostatic fluid containment system apparatus10in the partially raised closing state. Fluid from upstream catchment12has entered inlet grate15and started filling chamber16. Fluid levels in collection sump26has risen to a point where the displacement mass of buoyant wall base20is greater than the total mass of buoyant wall14. The configuration size of buoyant wall base20is in such a way that seal rubber22remains above rising fluid levels to restrict particles in suspension from being attached to rubber seal22. Pivot sealing guide21follows the profile of chamber wall16as the unstable equilibrium centroid of displacement volume from buoyant wall base20rotates the top of buoyant wall14towards contained fluid in catchment12. This rotation and positioning of pivot sealing guide21facilitates the interlocking connection between angled bracket seal17and pivot sealing guide21which ensures the correct mating of components.

FIG. 5depicts the hydrostatic fluid containment system apparatus10in the raised closed state. Fluid has filled chamber16raising buoyant wall14to the fully closed position creating vertical hydrostatic forces on buoyant wall base20which compresses sealing rubber22between pivot seal18. Pivot sealing guide21is connected with angle bracket seal17which has horizontally compressed sealing rubber22against pivot seal18due to the tapered shape of pivot sealing guide21. Vertical forces from buoyant wall base20which pivot the top of buoyant wall14towards contained fluids on upstream catchment12are counteracted by horizontal hydrostatic forces from the contained fluid which pivot the top of buoyant wall14towards downstream dry zone13. Vertical partitions28act as vertical support beams to reduce vertical and horizontal bending moments on buoyant wall14. Pivot sealing guide21and angled bracket seal17create a fixed point to which vertical partitions28are attached when buoyant barrier14is in the raised closed position. Support beam19restricts horizontal deflection loads applied by the contained fluid from deforming buoyant wall14when in the raised closed position.

FIG. 6depicts the hydrostatic fluid containment system apparatus10in the raised closed state detailing the boundary wall11sealing configuration. Sealing rubber22is compressed between buoyant wall14and guide wall frame24by horizontal hydrostatic forces from contained fluid in catchment12. Tension brackets23prevent wave motion in the upstream catchment12from creating negative pressures on buoyant wall14and support bracket19which could allow fluid flows to the downstream dry zone13. The float activated pump25non-return valve31on discharge drain27is in the closed position until the pump is activated when contained fluid in upstream catchment12subside.

FIG. 7depicts the hydrostatic fluid containment system apparatus10in the raised closed state when contained fluid in catchment12has subsided. Float activated pump25conveys fluid through discharge drain27and past non-return valve31expelling fluid from chamber16to either upstream catchment12or downstream zone13depending on the existing drainage system surrounding the apparatus. Buoyant wall14lowers back into chamber16as depicted inFIG. 3when the contained fluid is expelled by pumping means as described inFIG. 7or siphon and gravity means as described inFIG. 8andFIG. 9respectively.

FIG. 8depicts the hydrostatic fluid containment system apparatus10in the raised closed state when contained fluid in catchment12has subsided. A siphon tube32with attached air break and isolation valve can be attached to chamber16where the downstream dry zone13is lower than upstream catchment12such as underground car park installations. As fluid fills chamber16it also flows through siphon tube32which becomes self-primed by fitting an air break device and isolation valve to siphon tube32. When the contained fluids subside at catchment12the isolation valve can be opened which will drain chamber16of fluid and lower buoyant wall14to its open resting state as depicted inFIG. 3.

FIG. 9depicts the hydrostatic fluid containment system apparatus10in the raised closed state when contained fluid in catchment12has subsided. A gravity discharge drain27can be used to expel fluid from chamber16and fitted with a non-return valve31when the upstream catchment12fluid levels subside lower than catchment sump26such as a river, waterway or esplanade installation.

FIG. 10depicts the hydrostatic fluid containment system apparatus10in the lowered open state showing design flexibility by not requiring any support structures on the upstream catchment12side of the device. The internal taper on rebate chamber16may be increased so a filtration screen33can be installed to prevent water borne pollutants from entering collection sump26.

FIG. 11depicts the hydrostatic fluid containment system apparatus10in the lowered open state showing design flexibility by not requiring any support structures on the upstream catchment12side of the device. The distance between buoyant wall14and the internal upstream wall on Chamber16may be increased so a filtration basket34can be installed and retain large volumes of water borne pollutants from entering collection sump26.

FIG. 12depicts the hydrostatic fluid containment system apparatus10in the lowered open state showing design flexibility by not requiring any support structures on the upstream catchment12side of the device. Chamber16can 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 zone13of the installation.

DETAILED DESCRIPTION AND BEST MODE OF IMPLEMENTATION

It is preferable that the hydrostatic fluid containment system apparatus be constructed from 150 mm 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 chamber16and 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. Chamber16is preferably located between smooth boundary walls11to facilitate watertight joins between vertical guide wall frames24which should be constructed from 5 mm thick stainless steel angle extrusions to prevent stormwater passing between boundary walls11and buoyant wall14from reaching dry zone13.

It is preferable that sealing rubber22be constructed from 25 mm diameter half round hollow rubber tube with a 25 mm 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 rubber22to buoyant wall14. Pivot sealing guide21should be tapered at 10 degrees to allow for a smooth transition when compressing sealing rubber22and pivot seal18.

Pivot seal guide21constructed from rigid material to prevent deformation and attached directly to vertical partitions28on buoyant wall14to enable a stable connection with limited joins between support beam19through to angled bracket seal17. Pivot sealing guide21should have friction resistant material such at HDPE attached to the edge facing chamber16wall to prevent gouging. Angled bracket seal17, pivot seal18, support bean19and tension brackets constructed from 5 mm thick stainless steel extrusions. Angled bracket seal17should have elongated holes for fasteners30which allows calibration to obtain a watertight seal if manufacturing tolerances are not met during construction of buoyant wall14.

Buoyant wall14should be constructed from closed cell foam laminated in 2 mm stainless steel metal sheet or hollow roto moulded polyethylene plastic for extra impact and corrosive resistance. Vertical partitions28should be 5 mm thick and 100 mm wide to provide sufficient rigidity and prevent deflection of buoyant wall14.

Inlet grate15should withstand vehicular traffic and be removable for servicing and maintenance of chamber16. Filtration screen32and basket33will be constructed from corrosion resistant material with aperture sizes of between 1.5 and 3 mm to prevent debris from interfering with the movement of buoyant wall14and the water sealing rubber22.

It is preferable that in the current configuration, buoyant wall14is 100 mm wide while the buoyant wall base20is 200 mm wide and 200 mm deep to provide enough hydrostatic force to lift a 500 mm tall buoyant wall14. A gap between collection sump26and buoyant wall base20is required to stop compressive forces from traffic above from deforming buoyant wall14.

Float activated pump25should be submersible with 32 mm diameter discharge drains27for both pumped and siphon32pipes. It is preferable that float activated pump25has twin activation heights, initially when the collection sump26fluid level is just below the lifting displacement volume of buoyant wall base20and disengage when fluid levels are above ground surface level, then re-engage when fluid in the upstream catchment12subsides back to ground level. This operation will ensure buoyant wall14will remain below ground when small volumes of fluid enter chamber16and disengage pump from operating when the buoyant wall14is in the raised open position until upstream catchment12has 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.