MOVABLE WEIRS
Year: 1886

page_text: I, SAMUEL HARRISON, 5 Hall Yard, Kirkgate, Ripon, Yorka do hereby declare
the nature of my invention for MOVABLE WEIRS and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement :-
These movable weirs are intended to allow floods to pass whilst maintaining the
height of water at a nearly uniform level. They have the advantages, in ordinary
freshets, of an automatic weir, being self righting but in an extraordinary flood
they have the power of laying themselves flat on the ground & so not presenting
any obstruction to the flow of the stream.
Each sheet of drawings shews in full black lines the plane A B D, the block I,
the strut B E and the double-link B C D, when the weir is in its highest position;
the top dotted line of plane, shews how far it can move & still retain the power of
self righting & the other dotted lines shew weir, in a heavy flood or when under
control descending to the ground. The plane A B D may be of any material only
it be strong enough to sustain the thrust & pressure of the water held up; it is
hinged to & moves with the end of the strut at B and also hinged to & moves with
the end of the double-link at B. The plane is most sensitive when balanced on
the hinge B.
The strut B E is hinged to the plane at B & also hinged to the support at E
which is immovable; the position of the hinge B is decided by the depth of water
required & will generally be from to the height of plane; the support at E can
be any convenient distance from D.
The double-link B C D is hinged to the plane at B, also to a fixed support at D
& has a joint at C; this double-link, when the weir is at its highest is parallel or
nearly so with the plane; the hinge joining the two links at C must have a
knuckle-joint or be so constructed that the links can only move outwards that is
towards upstream; the joint C must be so situate as to allow the plane to lie flat
on the ground; the mode of securing this is shewn in the drawings.
The block I is so fixed, that when the plane has moved into a nearly horizontal
position or to any position that may be considered suitable, it will move the top
Link BC forwards & so cause the whole to descend this motion may also be secured
by a stop in the joint B.
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page_text: The lift H is not an absolute necessity but will be useful in regulating & con-
trolling the weir, from the banks of the stream; it may be a ram, a screw, a cam,
a chain or a rope & fixed in any convenient position; that shewn in the drawing
being considered best.
The mode of action is this-when the centre of pressure of water rises above
the joint B the plane will tilt & can move as far as the dotted line & still retain
the power of returning to its highest position but if the flow of water is greater
than this position can allow to pass the plane will tilt further & with the block
cause the joint C of the double-link to move & so lower the weir to the ground
giving then an unobstructed waterway.
A hollow in the ground in front of the weir would make its action more
efficient.
The lift H will raise or lower the weir by other means than that of the pressure
of water & will set the weir in any position to suit any flow of water.
CLAIMS:
- 1. The power for the plane to tilt till it is nearly horizontal & still be able to
return to its highest position.
2. The power for the weir to lay itself perfectly flat on the bed of the stream.
3. The power to raise or lower the weir by artificial means.
4. The combination of the plane, the block, & the strut with the double-link.
5. The combination of the plane, the block, the hinged strut, the hinged double-
link with the lift H.
:
Dated this 98th day of Inl. 100g