A dropdown flood barrier (100) is disclosed, which comprises at least one panel (102) and an associated counterweight (104), the panel configured to be movable between an elevated position and a lowered position in cooperation with the counterweight; and at least one rotatable drive (106) coupled to the panel, and is configured such that rotation of the rotatable drive enables the panel to be moved from the elevated position to the lowered position, the rotatable drive includes a brake arranged to exert a force against the rotation of the rotatable drive when a speed of the rotation exceeds a predetermined threshold, wherein in use, the rotatable drive is activated to enable the panel to controllably move under its own weight from the elevated position to the lowered position to form a barrier against flood water, the controllable movement of the panel enabled by the brake of the rotatable drive and the counterweight.

An axis positioning mechanism serving as a rotation bearing of a flap gate includes a housing disposed at the bottom of an opening, a first rotating plate rotationally supported by the housing via a first shaft, a second rotating plate rotationally supported by the housing via a second shaft having a different axis from the first shaft, and a synchronizing rod rotationally connected to the rotating plates so as to synchronize the rotations of the rotating plates. The axis positioning mechanism further includes connecting members rotationally connecting a door base and the rotating plates with different axes. The door is laid flat with a pivot at a higher position than the axes.

Described herein is a floating flap gate including a gate leaf having a buoyancy forming portion, the gate leaf being configured to be raised due to buoyancy effect (e.g., from water), a bottom fitting mounted to a proximal end portion of the gate leaf, the bottom fitting having a convex circular arc-shaped surface across a width direction of the gate leaf, a plate member having a concave circular arc-shaped surface to be mated with the convex circular arc-shaped surface of the bottom fitting when the gate leaf is in a lowered state, wherein the concave circular arc-shaped surface is in contact with the convex circular arc-shaped surface when the gate leaf is raised.

Described herein is a floating flap gate including a gate leaf having a buoyancy forming portion, the gate leaf being configured to be raised due to buoyancy effect (e.g., from water), a bottom fitting mounted to a proximal end portion of the gate leaf, the bottom fitting having a convex circular arc-shaped surface across a width direction of the gate leaf, a plate member having a concave circular arc-shaped surface to be mated with the convex circular arc-shaped surface of the bottom fitting when the gate leaf is in a lowered state, wherein the concave circular arc-shaped surface is in contact with the convex circular arc-shaped surface when the gate leaf is raised.

A pressure-tight door allowing movement of hinges includes: a hinge fixating part including a fixed member having one surface with a movable groove formed therein and the other surface fixed to a door frame, and a movable member having one surface inserted into the movable groove so as to slide bidirectionally on the movable groove and a hinge attached to the other surface of the movable member, connected to a door and sliding together with the movable member. The movable member of the hinge fixating part slides inwardly together with the hinge only when the pressure due to flooding or explosion is applied to the pressure-tight door, whereby the pressure-tight door is able to effectively block any leakage by compressing the gasket.

A pressure-tight door allowing movement of hinges includes: a hinge fixating part including a fixed member having one surface with a movable groove formed therein and the other surface fixed to a door frame, and a movable member having one surface inserted into the movable groove so as to slide bidirectionally on the movable groove and a hinge attached to the other surface of the movable member, connected to a door and sliding together with the movable member. The movable member of the hinge fixating part slides inwardly together with the hinge only when the pressure due to flooding or explosion is applied to the pressure-tight door, whereby the pressure-tight door is able to effectively block any leakage by compressing the gasket.

The invention relates to a friction reduced and ice resistant water control gate abutment plates that permit, without damage to the concrete, large relative thermal movement between the abutment plate assembly and the concrete abutment or pier to which the assembly is attached. Features that provide ease of maintenance, tight sealing and debris damage resistance are also disclosed.

An arrangement for controlling and measuring flow. The arrangement includes a fluid control barrier and a flow-measuring apparatus upstream of the fluid control barrier. The fluid control barrier includes a pair of plates for opening and closing a pipe, and the plates are movable towards a center line of the pipe to open the pipe and produce a symmetrical flow profile for the flow-measuring apparatus.

An arrangement for controlling and measuring flow. The arrangement includes a fluid control barrier and a flow-measuring apparatus upstream of the fluid control barrier. The fluid control barrier includes a pair of plates for opening and closing a pipe, and the plates are movable towards a center line of the pipe to open the pipe and produce a symmetrical flow profile for the flow-measuring apparatus.

The invention relates to improved water control gates and related inflatable actuators, and associated sealing, manufacture and operation apparatus and methods. Advancements in technologies related to air fitting design, inflated bladder stress relief, inflatable bladder strength enhancement, water gate related slide friction mitigation, abutment and other impounded water seals, gate panel fabrication, traffic accommodating water impoundment structures, and water gate panel system operation efficiency, as well as nappe aeration, hinges, and bladder manufacture technology are disclosed herein.