An Herodotus machine, or bottom-source, up-stair, hybrid pump and step lock system, includes synchronized reciprocating cross-gate displacers with commonly synchronized gates and floating body movers; specifically including a sequence of ascending adjacent step locks separated by gates with reciprocating gears on axles aligned over respective gates. A chain over each reciprocating gear has a displacer on each end, with one displacer in the upper lock and the other displacer in the lower lock. Rotating first, the downstream displacer descends to raise the lower lock water level, while the upstream displacer rises to lower the upper lock water level, and vice versa on the reverse gear rotation. Displacers are sized such that water levels in alternate pairs of upper lock and lower lock are made the same. The gate is then opened and a watercraft can be transferred from the lower lock to the upper lock or vice versa.

An Herodotus machine, or bottom-source, up-stair, hybrid pump and step lock system, includes synchronized reciprocating cross-gate displacers with commonly synchronized gates and floating body movers; specifically including a sequence of ascending adjacent step locks separated by gates with reciprocating gears on axles aligned over respective gates. A chain over each reciprocating gear has a displacer on each end, with one displacer in the upper lock and the other displacer in the lower lock. Rotating first, the downstream displacer descends to raise the lower lock water level, while the upstream displacer rises to lower the upper lock water level, and vice versa on the reverse gear rotation. Displacers are sized such that water levels in alternate pairs of upper lock and lower lock are made the same. The gate is then opened and a watercraft can be transferred from the lower lock to the upper lock or vice versa.

The present invention provides an acoustic flow meter assembly (2) for pipes or open channels, said assembly including a frame (24) with a predetermined geometry. The frame has at least one user accessible port (36-42) with the at least one user accessible port (36-42) adapted to receive an interchangeable cartridge (44) which contains at least one acoustic transducer (46) to measure fluid velocity through said frame (24).

The present invention provides an acoustic flow meter assembly (2) for pipes or open channels, said assembly including a frame (24) with a predetermined geometry. The frame has at least one user accessible port (36-42) with the at least one user accessible port (36-42) adapted to receive an interchangeable cartridge (44) which contains at least one acoustic transducer (46) to measure fluid velocity through said frame (24).

According to one embodiment, a flood vent includes a frame forming a fluid passageway through an opening in a structure. The flood vent further includes a door pivotally mounted to the frame in the fluid passageway for allowing a fluid to flow through the fluid passageway. The door has two opposing faces that include a first face and a second face. The flood vent further includes a first float positioned within the door in a location in-between the first face and a second float. Additionally, the first float is configured to allow the door to pivot in a first direction. The flood vent further includes the second float positioned within the door in a location in-between the second face and the first float. Furthermore, the second float is configured to allow the door to pivot in a second direction.

According to one embodiment, a flood vent includes a frame forming a fluid passageway through an opening in a structure. The flood vent further includes a door pivotally mounted to the frame in the fluid passageway for allowing a fluid to flow through the fluid passageway. The door has two opposing faces that include a first face and a second face. The flood vent further includes a first float positioned within the door in a location in-between the first face and a second float. Additionally, the first float is configured to allow the door to pivot in a first direction. The flood vent further includes the second float positioned within the door in a location in-between the second face and the first float. Furthermore, the second float is configured to allow the door to pivot in a second direction.

A flood vent includes a door pivotable within a frame between a closed position and an open position. A fluid trigger that is triggerable by a fluid to allow the door to pivot from the closed position to the open position includes a retainer and a fluid modifiable material. The fluid modifiable material is positioned between the door and the retainer thereby obstructing the door from pivoting from the closed position to the open position until the fluid modifiable material is modified by contact with the fluid.

A flood vent includes a door pivotable within a frame between a closed position and an open position. A fluid trigger that is triggerable by a fluid to allow the door to pivot from the closed position to the open position includes a retainer and a fluid modifiable material. The fluid modifiable material is positioned between the door and the retainer thereby obstructing the door from pivoting from the closed position to the open position until the fluid modifiable material is modified by contact with the fluid.

A watertight structure in a flap gate 1 provided with a weight-balance supported door 2 to open an opening 200 of a floodgate 100 in a state in which no external force other than gravity is applied, wherein the structure has: a gap opening-closing member 72 that oscillates in the water flow direction and opens and closes a gap C, wherein the gap C is provided between the lower edge 23 of the door 2 and the bottom face 300 of the floodgate 100 in a state in which the door 2 is blocking the floodgate 100; and an opening operation assist means 73 for operating the gap opening-closing member 72 so as to be in an open state by lifting same toward the outer water side.

The present invention provides an acoustic flow meter assembly (2) for pipes or open channels, said assembly including a frame (24) with a predetermined geometry. The frame has at least one user accessible port (36-42) with the at least one user accessible port (36-42) adapted to receive an interchangeable cartridge (44) which contains at least one acoustic transducer (46) to measure fluid velocity through said frame (24).