IMPROVEMENTS IN SELF-ACTING FLOOD GATES, SLUICES, OR TURNING GATES
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by James Ball Mannix and William
Sidney Cox at the Office of the Commissioners of Patents on the 11th June
1879.
JAMES BALL MANNIX and WILLIAM SIDNEY Cox, both of Limerick, Ireland, Civil
Engineers. "IMPROVEMENTS IN SELF-ACTING FLOOD GATES, SLUICES, OR TURNING
GATES."
This Invention has for its object to allow pent up water to escape when it has
attained a given height, or a given relative height to the level of the water into
which it is to be discharged by the self action of the flood gate, sluice, or turning
gate itself, and independently of any special apparatus or personal attention to
regulate the same.
An ordinary turning-gate is constructed with one side somewhat wider from the
vertical line of axis than the other, so that the sea or other backwater should have
the power of shutting it. The sides of such gates are parallel with the axis, or
intended to be so, and fit against their respective reveals. Such gates can only act
by resisting a return current, such as the sea when it rises above the level of the
outgoing current of the stream which the gate is intended to protect from flood.
Now our Invention is not only intended to resist the return current of the
back water or inlet of the sea, but it will cause the stream to be dammed up to any
desired height or relative level to the back-water or influx of the sea or other water;
and when such height has been attained, the stream, by its own action or pressure
against the gate, will cause the latter to turn or open and give free passage to the
excess of water that may arise and thereby allow it to escape without the aid of
any special apparatus or personal attendance, and this we accomplish in the
following manner :—
The flood or turning gate, according to our Invention, is provided with pivots
placed at the top and bottom of the gate in the usual manner, but the sides of
the gate instead of being made parallel to the axis or common centre line of the
said pivots, we incline to or from such axis or line in such manner that the
opposite sides of the gate present more or less relative area to the pressure of the
water, according to the relative height or level of the same. Thus according to our
Invention the foot or lower part of the gate may be made so that at one side of
the pivot it may extend 10 feet, whilst at the other side it may extend only 2 feet.
But the sides being made inclined as above stated, the side commencing at 10 feet
may incline so much that at the top of the gate it will approach the top pivot to
within 2 feet, whilst the opposite side has been extended to 10 feet.

page_text: Therefore there will be in accordance with the difference of level of the water at
the respective sides of the gate, a variable degree of pressure exerted upon the two
sides of the gate, and at a certain relative point the pressure may become so great
as to press open the gate and allow the pent up water to escape, although the
pressure of the backwater or sea inlet would not have the same effect.
This we accomplish as already stated by varying the relative areas (with
reference to their height) of the opposite sides of the gate, increasing the area of
one side as the other decreases, which may be done either by making the sides
tapering or inclined, or by various projections formed on the sides of the gate. By
so forming the opposite lateral edges of the gate, any given relative levels of the 1
water at its respective sides may be obtained, for on exceeding the predetermined
level the pressure of the outflowing current will overcome the resistance of the gate
and allow the water to escape.
When the water has subsided to the given level as
desired, the gate will again close.
It will be evident that the framing of the gate with the necessary sill, head, 1
reveals, and pivots may be constructed either of wood or iron as in ordinary cases,
the essential feature of our Invention being the forming the opposite sides of the
gate, with reference to the line of axis, with a varying surface or arca for the
purposes above described.
Gates as described may be made with one side vertical, which will facilitate the 2
arrangement of the masonry piers.