Abstract: A mechanical closure device comprises an enclosure having four sides, a top and bottom and defining a discharge opening at the bottom. A floodgate assembly is interiorly removably mounted to the enclosure and comprises a pair of doors pivoted on a hinge assembly between an opened position and closed position. In the closed position, the doors seal against the flange to prevent passage of water through the discharge opening. A discharge drain assembly is preferably disposed on one door and has an opened and a closed position. An appendage is provided to facilitate opening and of the door. Upon removal, the floodgate assembly is stably positionable on a multipositionable service rack. A multipurpose tool is employed unlatching the floodgate doors and slidably removing the floodgate assembly.

Abstract: According to one embodiment, a flood vent panel includes a plurality of insulation pieces positioned together, and a panel frame surrounding the plurality of insulation pieces. The flood vent panel is configured to be coupled to a frame positionable into an opening in a structure, so as to at least partially block a fluid passageway through the opening in the structure. One or more of the plurality of insulation pieces are configured to uncouple from the flood vent panel when at least a predetermined amount of pressure is applied to a portion of the flood vent panel by one or more of a fluid or an object carried by the fluid, so as to reduce an amount of blockage of the fluid passageway provided by the flood vent panel.

Abstract: The flow control gate for detention ponds includes a movable gate that discharges fluid at a constant flow despite the depth of the fluid for a given depth range. The gate is moved by a lever that supports a float on the opposite end of the lever than the gate. As the fluid level around the flow control gate changes, the float tracks the changes, therefore raising and lowering the gate. Since the fluid head to discharge area relationship is not linear in the orifice equation, the curved track that the lever rests on is shaped in such a way so that the gate is moved non linearly to match the orifice equation. The flow control gate for detention ponds does not use electricity and can vastly reduce the required size of detention ponds.

Abstract: The invention discloses an overshot control gate for use with trapezoidal irrigation channels. A gate has a rigid rectangular section adapted to, in use, be pivotally mounted to a base of a trapezoidal irrigation channel. A pair of triangular sections are pivotally mounted on opposite sides of the rigid rectangular section. Each of the triangular sections are divided into first and second triangular sections with a common apex at the base of the trapezoidal irrigation channel. Each of the first triangular sections are rigid and adapted to, in use, be pivotally mounted to opposite side walls of the trapezoidal irrigation channel. Each of the second triangular sections including the pivotal mounting on opposite sides of the rigid rectangular section are formed of a flexible material. Also disclosed is a pipe flow meter and a duckbill valve.

Abstract: A flow control system for a body of water includes a floating portion that is covered by a shroud and includes a buoyant member. The floating portion has an inlet portion within the shroud and the inlet portion is suspended distal from the floating portion forming a gap. A stationary portion is interfaced to a containment surface of the body of water and is in fluid communication with a drainage system. An extendable member is interfaced to the inlet portion, fluidly interfacing an orifice of the inlet portion to the stationary portion, and therefore to the drainage system. When in use, fluid from below a surface of the body of water flows through the gap, into the orifice, through the extendable member, and out through the drainage system. The flow rate of the fluid is constant through a range of depths of the body of water.

Abstract: The present invention provides a floating flap gap which has a door body with a forward end which is able to swing upwards, in a direction in which the water flows into an opening or at an access way, around a base end thereof serving as a fulcrum. The door body is attached to one end of a wire rope, and an auxiliary force generating means is attached to the other end thereof. This structure makes it possible to prevent an overflow during the initial influx of water and to enhance the ability of the door body to follow the water level when the door body begins to lower. This structure additionally makes it possible to mitigate a shock which occurs when raising of the door body is completed and when lowering of the door body is completed.

Abstract: A flow control system of the present invention includes a movable riser slideably engaged with a stationary riser and having a flange. The stationary riser is interfaced to a downstream drainage system. The movable riser is made buoyant by one or more floats such that, as the water level around the flow control system changes, the movable riser follows the changes based upon the buoyancy of the float(s), thereby maintaining the flange at a constant depth. The gap between an upper edge of the flange and the inner perimeter of the stationary riser coupled with an area of the gap defines a flow rate that is constant. Vents couple an inner cavity of the movable riser to air above the fluid, the inner cavity being in communication with the drainage system as well.

Abstract: Provided is a flood protection system for protecting an area from flooding water, wherein the area includes a trench defined at least along a portion of the boundaries thereof and a at least one depression on the side of the trench facing away from the area to be protected. The system comprising a barrier, configured for being at least partially fitted in the trench; and a float coupled to the barrier and being configured for at least partially is disposed in the depression. The float is configured for rising in response to a rise in the water level inside the depression and about the boundaries of the area. The float is further configured for lifting the barrier out of the trench therewith, thereby blocking the waters from entering the area.

Abstract: To prevent a door body from shaking significantly when it rises. A floating body flap gate is provided which is disposed on a roadway surface in an opening; and causes a door body to rise to block the opening when water is trying to flow in from the opening by using a water pressure of the water which is trying to flow in and a buoyancy of the door body. The door body is formed with three door body blocks, which are separated in the vertical direction. These door body blocks which are separated in the vertical direction, are connected by rotation mechanisms for rotation at a specified angle within a vertical plane in a direction in which the water is trying to flow in from the opening. The door body is not subject to significant shaking, regardless of the water level at which the water tries to flow in from the opening.

Abstract: An opening/closing device 1 according to the present invention includes a gate 10 that receives a flow of a sewage W in an upright state, and can fall toward a downstream side of the flow and a first spring 52a that generates a force for bringing the gate 10 into an upright state, wherein the first spring 52 generates a force insufficient for bringing the gate 10 into the upright state if the gate 10 is in a fallen state, and generates a force sufficient for bringing the gate into the upright state if the gate 10 is tilted by an angle equal to or less than a predetermined angle.

Abstract: A flow control system of the present invention includes a movable riser slideably engaged with a stationary riser and having a flange. The stationary riser is interfaced to a downstream drainage system. The movable riser is made buoyant by one or more floats such that, as the water level around the flow control system changes, the movable riser follows the changes based upon the buoyancy of the float(s), thereby maintaining the flange at a constant depth. The gap between an upper edge of the flange and the inner perimeter of the stationary riser coupled with an area of the gap defines a flow rate that is constant. Vents couple an inner cavity of the movable riser to air above the fluid, the inner cavity being in communication with the drainage system as well.

Abstract: A flow control system includes a movable riser with multiple flow rate restrictors within a stationary riser that is interfaced to a drainage system. The movable riser is buoyed by float(s) attached to the movable riser. As the fluid level around the flow control system changes, the movable riser tracks the changes, thereby raising and lowering the flow rate restrictors. Since the flow rate restrictors have differing areas in the horizontal plane, an interstitial opening between the outer edge of each flow rate restrictor and the inner perimeter of the stationary riser differs. The flow rate is constant and proportional to the depth of the fluid over the interstitial opening with the least area. The flow rate remains constant until that flow rate restrictor creating the smallest interstitial opening lifts above the upper edge of the stationary riser at which time, the next flow rate restrictor determines the flow rate.

Abstract: An opening/closing device includes a gate that receives a flow of a sewage, and can fall toward a downstream side of the flow, a fall prevention unit that prevents the gate from falling by supporting the gate, a support release unit that releases the support for the gate by the fall prevention unit, a first float that is arranged on the upstream side of the gate, and is smaller in specific gravity than the sewage, a surfacing prevention unit that prevents the first float from surfacing, a second float that is arranged on the upstream side of the gate, above the first float, and is smaller in specific gravity than the fluid, and a surfacing-prevention release unit that releases, resulting from surfacing of the second float, the prevention of the surfacing of the first float by the surfacing prevention unit. Further, the support release unit is activated resulting from surfacing of the first float.

Abstract: An application for a flow control system includes a movable riser in fluid communication and slideably engaged with a stationary riser, the stationary riser being in fluid communication with a drainage system. The movable riser is made buoyant by one or more attached floats such that, when the liquid level around the flow control system increases to a pre-determined level, the movable riser lifts due to the buoyancy of the float(s), thereby maintaining the pre-determined displacement as the water level continues to rise, yielding either a constant flow rate or a variable, predictable flow rate through the drainage system.

Abstract: A low profile backwater valve includes a hollow valve body having an inlet, an outlet, and a bottom. A pivoting valve member is pivotally movable between a normally open position along the bottom of the valve body and a closed position sealing the inlet. The valve member has a hinge end, a remote end, and opposed sides. A float is positioned as an appendage along at least one of the opposed sides of the valve member, such that the float adds buoyancy to the valve member causing the valve member to float into the closed position in the presence of a backflow.

Abstract: The shore side of a shore line water barrier is protected from flooding caused by storm surge over-topping the barrier. Water overtopping the barrier, such as from wind waves crashing against the barrier, is trapped, impounded and accumulated between a parapet atop the barrier and walls on the sides of a buoyant gate unit taller than the parapet and walls and normally resident below grade on the shore side of the barrier, hinged about an axis generally parallel to the barrier and spaced from the parapet by a distance not less than the height of the gate unit. The accumulated overtopping water is applied to rotationally float the gate unit from the horizontal position initially principally by buoyancy and then principally by hydrostatic pressure to drive the gate unit to an upright position to oppose storm surges having a water level higher than the parapet.

Abstract: A system and valve for regulating the level of a fluid. The valve having a floating head member that is connected via a rotatable member to a drain member, where fluid may drain from the valve. The system having the valve and a tank, where the fluid drains from the tank once the fluid level reaches the level of the drain member of the valve.

Abstract: To prevent a door body from shaking significantly when it rises. A floating body flap gate is provided which is disposed on a roadway surface in an opening; and causes a door body to rise to block the opening when water is trying to flow in from the opening by using a water pressure of the water which is trying to flow in and a buoyancy of the door body. The door body is formed with three door body blocks, which are separated in the vertical direction. These door body blocks which are separated in the vertical direction, are connected by rotation mechanisms for rotation at a specified angle within a vertical plane in a direction in which the water is trying to flow in from the opening. The door body is not subject to significant shaking, regardless of the water level at which the water tries to flow in from the opening.

Abstract: An aqueduct assembly is provided as having a front gate assembly and a rear gate assembly. The front gate assembly has a front gate which will open to let water into the aqueduct assembly. When water begins to rise in the aqueduct assembly, a rear gate of the rear gate assembly opens to let water flow out of the aqueduct assembly. A method for diverting water is also provided. A front gate assembly opens for allowing water to flow into the aqueduct assembly. Subsequently, rear gate assembly opens for permitting water to flow out of the aqueduct assembly.

Abstract: An application for a flow control system includes a tapered plunger situated within an conduit. The conduit is open to a downstream drainage system. The tapered plunger is buoyant, assisted by one or more floats attached such that, when the water level around the flow control system increases to a pre-determined level above a top rim of the conduit, the tapered plunger lifts due to the buoyancy. In such, the flow rate is maintained substantially constant. At the emergency level, alternate drain systems provide increased drainage to reduce the potential of flooding.

Abstract: Embodiments are described for preventing downward flow of substantial surface water into an underground ventilation duct communicating upwardly to a ground surface opening. The embodiments comprise a support having a top opening and an opening in a lower portion above a floor. The opening in the lower portion is for venting communication with a proximate portion of the ventilation duct. The support supports at least one seat and paired buoyant gate set. The seat is mounted perpendicularly relative to the gate and a portion of a passageway under the seat for fluidly communicating beyond such portion to the top opening of the support and to the proximate portion of the ventilation duct. The buoyant gate is positioned lower than the seat and the passageway, is of sufficient size to block the passageway, and is responsive to water rising in the support by floatingly pivoting upwardly until engaging the seat, thereby blocking the passageway.

Abstract: An application for a flow control system includes a movable plunger held within a stationary riser, the stationary riser being in fluid communication with a drainage system. The movable plunger is buoyant, assisted by one or more attached floats such that, when the liquid level around the flow control system increases to a pre-determined level, the movable plunger lifts due to the buoyancy, thereby maintaining the pre-determined distance between the surface level and a bottom surface of the movable plunger, keeping the flow rate at an approximately constant level independent of the water level.

Abstract: A flow control system includes a movable riser with multiple flow rate restrictors within a stationary riser that is interfaced to a drainage system. The movable riser is buoyed by float(s) attached to the movable riser. As the fluid level around the flow control system changes, the movable riser tracks the changes, thereby raising and lowering the flow rate restrictors. Since the flow rate restrictors have differing areas in the horizontal plane, an interstitial opening between the outer edge of each flow rate restrictor and the inner perimeter of the stationary riser differs. The flow rate is constant and proportional to the depth of the fluid over the interstitial opening with the least area. The flow rate remains constant until that flow rate restrictor creating the smallest interstitial opening lifts above the upper edge of the stationary riser at which time, the next flow rate restrictor determines the flow rate.

Abstract: An automatic water flow regulator apparatus and a system for controlling and regulating the level of groundwater in an agricultural field. An automatic flow regulator adapted for use in a buried tile line that responds to conditions upstream and downstream along the line in order to regulate flow. A system having a tile line buried in a field for draining water therefrom, a preferably manually operated terminal control stand positioned at the discharge end of the system, and one or more automatic water flow regulators along the line for controlling the flow of water therethrough in conjunction with said terminal control stand.

Abstract: A buoyancy adjustment device utilizes an inflation valve connected between the diver's breathing gas supply and a compartment to admit gas into the compartment to increase the diver's buoyancy. An exhaust valve connects between the compartment and the outside of the vest, to release gas from the compartment to the surrounding environment to decrease the diver's buoyancy. A hand-operated controller connected to the inflation valve, when caused to move from a neutral position to an inflation position, actuates the inflation valve and admits gas to the compartment. The hand-operated controller is also connected to the exhaust valve via a flexible pushrod so that, when caused to move from the neutral position to an exhaust position, actuates the exhaust valve and releases gas from the compartment. The flexible pushrod is housed in a sleeve that is totally contained within the compartment.

Abstract: An application for a flow control system includes a movable plunger held within a stationary riser, the stationary riser being in fluid communication with a drainage system. The movable plunger is buoyant, assisted by one or more attached floats such that, when the liquid level around the flow control system increases to a pre-determined level, the movable plunger lifts due to the buoyancy, thereby maintaining the pre-determined distance between the surface level and a bottom surface of the movable plunger, keeping the flow rate at an approximately constant level independent of the water level.

Abstract: An application for a flow control system includes a tapered plunger situated within an conduit. The conduit is open to a downstream drainage system. The tapered plunger is buoyant, assisted by one or more floats attached such that, when the water level around the flow control system increases to a predetermined level above a top rim of the conduit, the tapered plunger lifts due to the buoyancy. In such, the flow rate is maintained substantially constant. At the emergency level, alternate drain systems provide increased drainage to reduce the potential of flooding.

Abstract: An application for a flow control system includes a movable riser in fluid communication and slideably engaged with a stationary riser, the stationary riser being in fluid communication with a drainage system. The movable riser is made buoyant by one or more attached floats such that, when the liquid level around the flow control system increases to a pre-determined level, the movable riser lifts due to the buoyancy of the float(s), thereby maintaining the pre-determined displacement as the water level continues to rise, yielding either a constant flow rate or a variable, predictable flow rate through the drainage system.

Abstract: An application for a flow control system includes a movable riser in fluid communication and slideably engaged with a stationary riser, the stationary riser being in fluid communication with a drainage system. The movable riser is made buoyant by one or more attached floats such that, when the liquid level around the flow control system increases to a pre-determined level above a top rim of the movable riser, the movable riser lifts due to the buoyancy of the float(s), thereby maintaining the pre-determined displacement as the water level continues to rise.

Abstract: A self-adjusting barrier incorporates a series of float units restrained between a primary wall, such as a bulkhead, and a secondary wall, such as sheetpile. The secondary wall may be braced to the primary wall. The float units slidably interconnect along adjacent edges to self-adjust along a perimeter, such as a marina or waterfront lot, based on the height of water within the chamber (stilling basin) provided between the two walls. Mechanisms for deterring vandalism and providing increased environmental integrity are also provided for select embodiments. Methods of employing the barrier are also disclosed.

Abstract: It is an object to provide a tide apparatus comprising a storage tank connected to a underground pit for normally storing water of a constant amount, a connecting pipe for connecting between the underground pit and the storage tank, and a seismograph releasing apparatus formed on the connecting pipe for sensing a shake in an earthquake and for releasing the water stored in the storage tank into the underground pit, wherein the tide plate can protrude upward from the soil foundation face by operating the seismograph releasing apparatus in an earthquake to make the water stored in the storage tank flow into the underground pit via the connecting pipe.

Abstract: Preventing a flood by lowering the water level of the water channel in the flood prone zone by methods consisting of pushing large quantities of water downstream and partially blocking the inflow of water at various strategic locations.

Abstract: The flood vent of the invention provides a frame configured for installation in a concrete block foundation wall in place of a single block. The frame includes an angularly oriented window. A gate is pivotally mounted at an upper end thereof within the frame to rest against the window, causing the gate to reside at an angle and be held closed by gravity. A float is mounted to the gate and positioned at rest below the lower edge of the frame to cause the gate to pivot toward an open position when flood water rises to a level approaching the wall opening.

Abstract: Embodiments are described for preventing downward flow of substantial surface water into an underground ventilation duct communicating upwardly to a ground surface opening. The embodiments comprise a support having a top opening and an opening in a lower portion above a floor. The opening in the lower portion is for venting communication with a proximate portion of the ventilation duct. The support supports at least one seat and paired buoyant gate set. The seat is mounted perpendicularly relative to the gate and a portion of a passageway under the seat for fluidly communicating beyond such portion to the top opening of the support and to the proximate portion of the ventilation duct. The buoyant gate is positioned lower than the seat and the passageway, is of sufficient size to block the passageway, and is responsive to water rising in the support by floatingly pivoting upwardly until engaging the seat, thereby blocking the passageway.

Abstract: A liquid barrier system automatically deploys when a predetermined liquid level is attained, thereby preventing water or other liquid from entering a structure through an accessway, and automatically retracts when the liquid level recedes. The liquid barrier system includes a float housing assembly installed substantially below grade and adjacent an accessway to a structure. The system also includes a float assembly having a float which is positionable within a float housing relative to a liquid level in the housing. A barrier assembly includes a barrier interconnected to the float, and one or more seal members disposed along a periphery of an accessway. In a high water event, the float rises with the liquid level in the float housing thus causing the barrier to automatically deploy into a sealing engagement with the seal member(s) along the periphery of the accessway, thereby preventing the entry of fluid into the structure.

Abstract: An anti-flooding device with possible displacement of the waters for the exploitation of water energy includes a double closing system with an outer or inner cylindrical element with automatic, semi-automatic or manual operation, a pipe-line provided with an opening at the surface level which assures a constantly equal water level in the basin, and below which there are a plurality of pipes which come out above the surface for the air passage and for being guided to a float connected to a tubular sluice-gate that closes an opening on the bottom of the main pipe-line.

Abstract: Apparatus (10) is defined for regulating the level of liquid on a first side of a barrier (12) with respect to a moveable level of liquid on a second side of the barrier. The apparatus includes an inlet conduit (30) for positioning on the second side of the barrier and having an inlet (38) that is arranged for moving up and down with the liquid level, and an outlet conduit (16) for positioning on the first side of the barrier (12) and in liquid communication with the inlet conduit (30) across the barrier. The outlet conduit has an outlet (22) that can be located at a predetermined liquid level at the first side.

Abstract: The flood vent has an elongated box-shaped frame having a top end, a bottom end including a floor, and opposing sidewalls that define a fluid passageway. The frame has an open front and a track formed in the rear of the frame. A door is slidably mounted in the track so that a normally closed position blocks the fluid passageway. The door is sufficiently buoyant to permit floodwater to float the door in the track and, thus, to automatically vent excess water through the fluid passageway. Installed in a crawl space, basement, or similar structure, the venting action of the flood vent limits hydrostatic pressure buildup against the walls of the structure when floodwaters rise, thus preventing structural damage from occurring.

Abstract: An apparatus for controlling the fluid flow rate from a drainage pond that is common in developed sites where the drainage pond is adapted to supply a degree of fluid capacitance so the runoff does not overflow downstream creek beds and the like. The method and apparatus for controlling the fluid draining from a pond comprises a system for allowing a higher flow that is allowed by regulatory bodies when the pond is at a lower level so the pond drains more quickly when it is at a lower water level. Thus the apparatus allows for a smaller retention pond.

Abstract: Passive control of fluid flow from a vessel is provided by a floating weir assembly. The assembly includes a float and a weir opening that is in fluid communication with an outlet from the vessel. The weir opening and the fluid path connecting the weir opening and the outlet are designed such that the rate of outflow is determined by the geometry and position of the weir opening. The weir opening is preferably vertically adjustable so that desired outflow rates can be specified.

Abstract: A muted tidal regulator adapted to be interposed between a tidal body of water and an inland area at least partially isolated from the tidal body of water by a physical barrier. The assembly includes a tide gate that is made up of a conduit connecting said tidal body of water to said inland area and a closure operable to selectively prevent water flow through the conduit. The assembly also includes an inland water level sensing device and a closure control assembly responsive to the sensing device and adapted to affirmatively permit water flow through the conduit when the sensing device senses an inland water level below a threshold.

Abstract: A tidal gate system for a regulating the flow of tidal waters between a first side and a second side of a main opening. The tidal gate system comprises a primary door member defining a regulated opening, a secondary door member sized and dimensioned to cover the regulated opening, a door float, and a regulation float Gravity biases the primary and secondary door members into their closed positions. The door float causes the secondary door assembly to move out of its closed position when a primary water level on the first side of the main opening exceeds a predetermined regulated opening level. The regulation float is operatively connected to the secondary door assembly such that the regulation float forces the secondary door assembly into its closed position when the primary water level exceeds a predetermined regulation float level.

Abstract: A flood gate is provided that includes a frame defining a fluid passageway, a door pivotally mounted in the frame for movement between a plurality of open positions to permit flow of fluid therethrough, and at least one latching mechanism for holding the door in the closed position. The latching mechanism can release the door when the fluid force meets a preset level, by floatation, or by flow actuation. In addition, the latching mechanism can reset the door to the closed position when the fluid force acting on the door drops below the preset level. The door can include a ventilation opening, an automatic louver assembly for controlling air flow through the ventilation opening and a screen covering the ventilation opening. The flood gate may include a retention mechanism for preventing the door from opening when the structure in which the flood gate is mounted, such as an overhead garage door is rotated or otherwise moved.

Abstract: There is described a novel fluid level control system, particularly useful for controlling the level of water flowing in an open channel. The fluid level control system comprises a gate having a flap portion interconnected to a lever portion. The flap portion is rotatable about a first pivot point. The system further comprises a frame which is fixed with respect to the flap portion. A linkage interconnects the flap portion and the lever portion, and is connected to the frame at a second pivot point different than the first pivot point. Under changing flow conditions in the channel, the present system operates by both: absolute movement of the lever portion and the flap portion, and (ii) relative movement between the lever portion and the flap portion. A fluid treatment system comprising the fluid level control system and a method for controlling the level of a flowing fluid are also described.

Abstract: A flood gate is provided which includes a frame defining a fluid passageway therethrough, a door pivotally mounted in the frame for movement between a plurality of open positions to permit flow of fluid therethrough, and at least one latching mechanism for holding the door in the closed position. The latching mechanism can sense a fluid force acting on the door and can release the door when the fluid force meets a preset level. In addition, the latching mechanism can reset the door to the closed position when the fluid force acting on the door drops below the preset level. The door can include a ventilation opening, an automatic louver assembly for controlling air flow through the ventilation opening and a screen covering the ventilation opening. The automatic louver assembly can contain at least one louver, a temperature sensitive actuating device and a member connecting the louver to the temperature sensitive actuating device and can open and close in response to ambient temperatures.

Abstract: A floating debris removal system has a bypass or overflow grate that is hinged at the top and positioned to swing downstream under certain conditions. The grate is fastened with a shear ring that will break when sufficient force is generated against the grate by the flow of overflow water and debris through the system. A plow-shaped member pivots off upwardly as flow increases. The member has a plow-shaped blade that spreads the flow across the inlet of the trap of the system to reduce the velocity of the flow. The shape and weight of the blade are selected for optimal function under a range of water levels and flow velocities, and can be altered to perform best for different installations. Debris pits are provided before or after the traps of the system to collect small suspended debris that is not removed by the traps. The pits are sized and configured to slow the velocity of the flow of that the suspended debris settles into the pits.

Abstract: A floating weir assembly for controlling the discharge of fluid from a fluid reservoir. The weir assembly includes a buoyant body preferably comprising a sidewall surrounding a central bottom opening. A weir is provided on the inside surface of the sidewall, and a gauge is provided on the opposite side of the sidewall's inside surface. The sidewall may provide a ballast chamber for holding ballast, such as sand. By adjusting the amount of the ballast, the depth to which the body is submerged can be varied. By distributing the sand circumferentially, the body can be leveled in the fluid to ensure accuracy of the weir. Because the sidewall is partially submerged, undesirable surface matter, such as oil and debris, is prevented from entering the weir. While there are many applications for this floating weir assembly, a preferred application is in the field of sewage treatment systems.

Abstract: A spa weir includes a support member forming an opening between a spa body interior and a filter housing interior. Two or more spa doors are located at the opening to control the flow of water through the opening, the spa doors being pivotally connected to one another and one of the spa doors being pivotally connected to the support member.

Abstract: An automatically self-erecting barrier which prevents ingress of flood water into a building. A float is provided which when inactive may serve as a doorstep, and which when active rises with the flood water to extend a barrier across a lower part of a doorway into the building. The barrier is guided at its lateral edge, and vertical channels may be fixed to the building on either side of the doorway. The barrier may be sealed to the channels by inflatable sealing elements.

Abstract: A backflow valve which includes a closure gate pivotally mounted along a substantially vertical pivot axis to one of the opposed sides of the valve body. A closure gate engaging profile positioned in a bottom of the valve body locks the closure gate in the open position. The closure gate is biased into the closed position. The closure gate moves to the closed position upon floating free of the closure gate engaging profile.