Abstract: A gate valve for use in controlling the level of a dam has a first plate with an aperture on an upstream face of the dam and a movable plate on the upstream side of the fixed plate, with apertures sized and dimensioned to operate as a scissors when the movable plate is urged in a linear motion parallel to fixed plate. One or more edges of the apertures in the plates are provided with a sharp edge or a serrate edge oriented to sever obstructing object present in the apertures when the valve is transitioning from an open position to a closed position.

Abstract: A flood flaps vent for sealing a building crawlspace includes: (a) a vent box portion including open opposite front and rear ends on either end of a vent passageway, the vent box including a top box portion with at least one flap slot adjacent a rear end portion of the vent box, and an opposite bottom box portion; (b) at least one flexible flood flap extending across the open rear end portion, with its upper edge seated in the flap slot, other side flap edges of the flood flap being unattached; and (c) a grate portion over the open front end portion of the vent box; the flood flap occluding the rear end portion of the vent box when it is in an at rest, home position. This simplified abstract is not intended to limit, and should not be interpreted as limiting, the scope of the claims.

Abstract: A flood flaps vent for sealing a building crawlspace includes: (a) a vent box portion including open opposite front and rear ends on either end of a vent passageway, the vent box including a top box portion with at least one flap slot adjacent a rear end portion of the vent box, and an opposite bottom box portion; (b) at least one flexible flood flap extending across the open rear end portion, with its upper edge seated in the flap slot, other side flap edges of the flood flap being unattached; and (c) a grate portion over the open front end portion of the vent box; the flood flap occluding the rear end portion of the vent box when it is in an at rest, home position. This simplified abstract is not intended to limit, and should not be interpreted as limiting, the scope of the claims.

Abstract: The disclosure concerns a fusible shutter for a water structure such as a river sill, or a spillway on a dam or on a protective dyke, including a solid element disposed on the top of the structure and held on top by gravity, forming a watertight or substantially watertight wall, installed on the water structure and being able to retract so as to allow water to pass without obstruction when the level of the reservoir or watercourse reaches a predefined level, a chamber being formed at the base of the solid element between the latter and the surface that supports it, pressurisation means enabling the chamber to be filled with water in order to create under the solid element a thrust directed upwards when the water in the reservoir or watercourse reaches the predefined level.

Abstract: A fluid level control system, particularly useful for controlling the level of water flowing in an open channel. The fluid level control system includes a gate having a flap portion interconnected to a lever portion. The flap portion is rotatable about a first pivot point. The system further includes 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: (i) 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 and a method for controlling the level of a flowing fluid may also use such a fluid level control system.

Abstract: A water control gate assembly comprises a self-actuating top-hung gate for controlling the flow of water in a waterway. The gate is pivotably mounted on a pair of piers located above an upstream of the gate for allowing the gate to pivot between a closed position and an open position in which water flows beneath the gate. The gate includes a ballast tank having an upstream inlet for charging the ballast tank and a downstream outlet for discharging the ballast tank. The upstream inlet is arranged to start charging the ballast tank with water in the event of the upstream water level reaching a first lower level. The downstream outlet is arranged to start discharging the ballast tank in the event of the upstream water level reaching a second upper level, with the ingress of water into the ballast tank between the first and second levels progressively increasing the closing moment of the gate and maintaining it closed against the progressively increasing opening moment of upstream water pressure against the gate.

Abstract: The gate of the present invention regulates the level of a downstream reach (4) by means of a sector-shaped plate (1) carried by a frame (6, 7) that oscillates about a axis (5) and that also carries a float (8) dipping into said reach. Substantially neutral equilibrium is obtained at a reference level by raising the center of gravity above the oscillation axis, and the reference level is adjusted by transferring water between two longitudinally offset tanks (11, 13). The invention is particularly suitable for irrigation networks.

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: An apparatus for automatically and selectively discharging saline water at a tide-preventing floodgate between the ocean and a river or like which comprises a tide-preventing floodgate provided between the ocean and a river or the like, a drainpipe for discharging saline water distributed in a lower portion of said river or the like and disposed on the utmost lower part of said floodgate, a distal end mouth opened at an end portion of said drainpipe to upright direction, a hollow float positioned at the distal end mouth of the drainpipe and supported by at least one support pole for guiding the ascending or descending motion of the hollow float, a communication path provided at a submarine level portion of said floodgate and a flexible communication pipe for communicating the inside of the hollow float with the sea water of downstream through said communication path, whereby said hollow float automatically ascends or descends so as to open or close said end mouth of the drainpipe with respect to a level diffe