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.

Abstract: A backwater valve (for preventing the flow of liquid in a reverse direction when water backs up in the valve) has a gate which sealingly engages the input opening to the valve chamber so as to prevent the flow of water out of or into the input opening. The gate is angularly moveable about a pivot point between a lower, closed position in which the input opening is closed by the gate and an upper, open position in which the input opening is open. Linked to the gate, but positioned angularly away from the gate, is a float. The float and the gate are linked such that gravity normally maintains the float in a lower position and the gate in the upper, open position but, when liquid backs up into the value, the float will float to an upper position thereby moving the gate into the lower, closed position thereby closing the input opening and preventing liquid from flowing out of the valve through the input opening.

Abstract: The invention relates to a movable dam for a water-course. This dam comprises a chamber which, for example, is formed in a dike or alike and wherein a buoyant body is housed supporting a vertical retaining wall. At its top the chamber communicates with the surroundings through a slot receiving the vertical retaining wall, whereas further a filling channel connects to said chamber and extends towards the watercourse. It is possible that a discharge channel is connected to the lower part of the chamber. Further sealing means may be provided.

Abstract: The weir gate includes a pair of spaced juxtaposed guides that are disposed vertically on either side of an opening between the interior of a spa and a filtration cavity. A lower gate is fixed to and spans the guides in a generally vertical plane. A floating gate is disposed between the guides, and can be placed in an upper position to regulate the flow of surface water into the filtration cavity and in a lower recessed position adjacent the lower gate to provide access to the filter cavity. An upper latch mechanism holds the floating gate in the upper position so that it pivots in a plane generally orthogonal to the lower gate and its upper edge floats near the surface of the water in the spa. A lower latch mechanism holds the floating gate in the lower position adjacent the lower gate so that a user can access the filters without having to hold the floating gate down.

Abstract: The method relates to a method and a device for controlling the flow of a liquid. In a well (10) having at least one inlet (11) and one outlet (12) the areas of said inlet (11) is adjusted in dependence on the liquid level in said well (10) by a floating body (13) controlled by said level. Said well is provided with an inlet tube (15) ended by said inlet (11), and at least one outlet (12), a floating body (13) arranged movable in a vertical direction in said well (10), and a slide (14) arranged in said well (10) in front of said outlet (12), said inlet tube (15) and said slide (14) being movable in relation to each other in dependence of a movement of said floating body (13) so as to close adjustably by said slide said inlet (11) of said inlet tube (15).

Abstract: A liquid barrier system includes a structure forming a below ground level float-receiving chamber. An inlet passageway for round water or other liquid directs the liquid into the bottom of said chamber to fill the chamber when it is desired that a barrier wall-forming part of the barrier system is to rise above ground level. Where the barrier system is a flood water barrier, the chamber bottom connects with a sewer system so that the chamber does not fill unless flood risk conditions exist, as when sewer back-up occurs. A float structure with which the barrier wall is associated is vertically movable in the chamber from a bottommost position therein when there is no liquid build up therein to an uppermost position when said liquid rises therein where the barrier wall is substantially above ground level. Seals are provided which prevent the liquid from gaining access to said one side of the barrier wall.

Abstract: The invention concerns a weir with an on a horizontal axis tilting gate (1). The control is automatic and completely mechanical and operates without an external source of energy. The control uses a float/counterweight (4) placed in an enclosure (5) which is in connection with the upstream level. The float/counterweight (4) is connected to the equator (13) on the gate (1) by a transmission mechanism consisting of (7), (10) and (11). The float/counterweight (4) is in balance with the hydraulic forces on the gate (1). The tilting axis is placed about 0.4 of the height of the gate (1) from the underside.During large discharges the gate (1) tilts further to increase the flow. This enables the weir to establish within shorter time the desired level. A horizontal submerged grate (15) prevents choking of the weir.The gate (1) can adjusted vertically by a leadscrew (16) to set the weirlevel. A threshold-beam (20) is connected to guidings (17) to the gate-equilibrium by every adjusted height.

Abstract: A valve is installed into an underground conduit to control drainage of water through that conduit. The drainage control valve includes a perforated plate across the conduit. The latter plate is formed with a peripheral groove rectangular in cross section and a hollow tube made of flexible material is inserted into this groove to seal the joint between the plate and the inner surface of the conduit. A flap also made of flexible material is applied against the upstream surface of the plate and is formed with a peripheral edge taper whereby pressure applied on the flap by water upstream of the drainage valve forces the edge taper against the upstream plate surface to form a sealed joint between these flap and plate. The upper portion of the flap is attached to the upper portion of the plate through screw and nut assemblies. These assemblies traverse rigid washers inserted in respective holes made in the flap.

Abstract: A system for controlling and preventing flooding of areas adjacent a waterway includes a multiplicity of interconnected flood gates located in the banks of the waterway. The system includes water level sensors and devices for moving the floodgates in response to signals from the water level sensors.

Abstract: An energy-efficient automatic sluice gate for sustaining a fluid level, separating an upstream pool from a downstream pool in an irrigation system and enabling the level of water in one of the pools to be kept constant at a settable value.

Abstract: A means and method for transporting fish from a lower body of water to a higher body of water. The means comprises a tubular lock with a gated entrance below the level of the lower body of water through which fish may enter the lock and a discharge passage above the level of the upper body of water. The fish raising means in the lock is a crowder pulled upward by a surface float as water from the upper body of water gravitationally flows into the closed lock filling it to the level of the upper body. Water is then pumped into the lock to raise the level to the discharge passage. The crowder is then caused to float upward the remaining distance through the water to the level of the discharge passage by the introduction of air into a pocket on the underside of the crowder. The fish are then automatically discharged from the lock into the discharge passage by the out of water position of the crowder.

Abstract: A self-regulating tide gate is installed on a conduit connecting an open body of water with a protected body of water. The tide gate comprises a mounting plate secured to the conduit at its end in the open body of water, the mounting plate defining an opening into the conduit. A door has its upper edge pivotally mounted at the top of the conduit, a door float is mounted to the door on its edge opposite the hinged edge and counterfloats are mounted to counterfloat arms extending from the door across the pivot axis thereof. When the water is below a critical level at which it is desired that the door close, the door float maintains the lower edge of the door on the surface of the water, thereby maintaining the door open and blocking debris from jamming the mouth of the conduit. As the water level rises, it acts on the counterfloat to pivot the door towards its closed position, whereafter the door is caught in the flow of water entering the conduit and rapidly pivoted to its closed position.

Abstract: An artificial dam or barrage which is adapted to be moved vertically from e bottom of the waterway in which it is installed is provided with a sheet of flexible material fixed to the bottom of the waterway and suspended with flexible cables above the bottom of the waterway.

Abstract: A perimeter skimming gutter for swimming pools is provided including a gutter conduit for disposition about the perimeter of a swimming pool and adapted to carry water at a level below a predetermined level of water in the swimming pool; a retaining wall on the pool side of the conduit over the top of which wall water may flow from the pool into the gutter conduit; a weir flow passage providing a fluid flow connection between the pool and at least one gutter conduit, entering the pool through the retaining wall at a level below the top thereof; and a fluid level responsive buoyant weir closure in the weir flow passage; a flow restriction in the weir flow passage confining normal weir flow through the weir flow passage to the gutter conduit to a predetermined maximum, the flow restriction blocking flow in excess of the predetermined maximum and thereby increasing fluid level in the weir flow passage between the weir closure and the pool; the weir closure responding to increasing weir flow passage fluid level t

Abstract: The salinity intrusion of ocean tidewater into a communicating fresh water river is prevented by laterally restricting the out-flow cross-section of the river with a series of flotation weirs and control weirs so that the surface level of the out-flow cross-section is higher than the surface level of the adjacent tidal salt water. The weirs are located so as to not obstruct the ship channel of the river.