Sluice-gate.
（Hydraulic Engineering.) a. Lock-gates of canals are provided with sluice-gates, as are also the sluice-walls in other structures where a flush is obtained by the sudden releasing of the pent — up water. The sluice-gate is a simple plate, which covers the opening, and is raised or lowered by means of a rackbar and pinion. See flushing.
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| Sluice-gate. |
Brunot's (Fig. 5215) is more particularly designed for application to dams erected for purposes of slack-water navigation, and is intended to be available when, in floods, the water has risen to such a hight over the head of the dam that the locks cannot be made use of. In the form illustrated, it consists of a hollow structure of timber or plate-iron. D D placed within a pit or chamber in the dam A B, which, as shown, is of crib-work filled in with stone, but may be of masonry. At each end of the pit is a well E E provided with a gate l l′, one of which communicates with the up-stream and the other with the down-stream side of the dam, and is raised or lowered by the shafts m m or other contrivances. The gate D D is also provided with valves, which are opened or closed to admit or withdraw water as required. At ordinary stages of water, it is retained at a level with the head of the dam and assists in retaining the water behind it; but when the river has risen to a considerable bight above the dam, one or more of the valves are opened, permitting the water to flow into the gate, which sinks, leaving the sluice open so that it [2219] may afford a passage for boat. When the gate D D is to be raised, the gate l′ of the down-stream passage of the well E is opened and the other gate l of the up-stream passage is closed, permitting the water to flow wholly or partially out of the pit, and the appropriate valve in the gate D D is also opened, allowing water to escape from and air to enter it, so that it will float. The valve is then closed and the action of the gates l l′ reversed, again filling the pit with water, upon which the gate D D rises and closes the sluice as before.
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| Sluice-gate for water-wheels. |
b. The gate which admits water to the scroll-chute of a water-wheel. In the example, this is worked by rack and pinion.
