Improvements in Apparatus for Drawing Off Liquid from Sewage Tanks.
Year: 1891

page_text: Date of Application, 25th June, 1891
Complete Specification Left, 25th Mar., 1892-Accepted, 30th Apr., 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Drawing Off Liquid from
Sewage Tanks.
I FREDERICK BIRD of 11 Great Castle Street, Regent Street, London, W.
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to the pivoted, floating, tubular arms used for drawing off
the supernatant liquid from sewage settling tanks, and it has for its object to cause
the valve by which the outflow is controlled to be opened or closed automatically
according to the position of the draw off tube in the settling tank in order that the
outflow of the effluent liquid shall be permitted only when the liquid level rises to
a certain height in the tank, and shall be arrested when the level falls so far that
the liquid would no longer be clear or the deposit of solid matter would be liable to
be disturbed. This may be effected by a pivoted valve which is caused to open
and close suddenly preferably under the action of a tumbler weight or weights acted
on in opposite directions by the pivoted draw off arm or tube at certain points of
its motion through arms attached thereto striking arms on the valve spindle.
Dated this 25th day of June 1891.
F. BIRD,
By A. M. & Win. Clark,
53, Chancery Lane, London, Patent Agents."
COMPLETE SPECIFICATION.
Improvements in Apparatus for Drawing Off Liquid from
Sewage Tanks.
I, FREDERICK BIRD of 11, Great Castle Street, Regent Street, London, W.,
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement:-
My invention relates to the pivoted, floating, tubular arms used for drawing-off
the supernatant liquid from settling tanks, and it has for its object to cause the
valve controlling the outflow to be operated automatically according to the height
of the draw-off tube in the settling tank, in order that the supernatant liquid shall
only be drawn off down to a certain level in the tank so as to ensure a clear effluent,
the valve being closed when the level falls beyond the point at which the liquid
would no longer be clear or the deposit of solid matter would be liable to be
disturbed. This may be effected by a pivoted or throttle valve which is caused to
open and close suddenly, preferably under the action of a tumbler weight or
weights acted on in opposite directions by the pivoted draw-off arm or tube at
certain points of its motion.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein
Figure 1 is an elevation, Figure 2 a cross-sectional elevation, and Figure 3 a
horizontal section, of as much of the apparatus as is necessary to explain the
improvement.
A is the draw-off tube pivoted upon a horizontal axis open at its upper end and
supported in an inclined position by a float B within a sewage settling tank, all as
usual, the hollow body portion A' being connected to the valve casing C by a
gland joint in which the body A' is free to turn and in which it is supported by an
end centre. The valve c is carried by a horizontal spindle c¹ mounted in casing C

page_text: and closes against seats c². D, E, are two weighted arms, fixed to opposite ends of
spindle and quartering, ie. in planes at right angles to each other. F, G, are
arins bolted to the body portion A', said arms also quartering (approximately) and
extending to such positions as to act on the arms D, E, respectively when the latter
are in a horizontal position.
In the position shewn in the drawing, the valve is closed and by the continued
rising of the float B and arm A the arm F is just about to act on the arm D and
move it upwards. By so doing, the arm E is brought to such position that it
preponderates over arm D and its weight causes the valve to suddenly open, as
indicated by the arrows. In the open position of the valve the arm E is horizontal
and arm D in the vertical plane of the axis e¹ and as the arm A descends by the
fall of the water-level the other arm G on the body portion A' strikes arm E,
raises it, and throws arm D over to such position that it preponderates over arm E
and closes the valve.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is―
In an apparatus for drawing-off the supernatant liquid from settling tanks, the
combination, with the pivoted, floating, draw-off tube, of a valve and mechanism
whereby the rise and fall of the draw-off tube is caused to open and close the
valve, substantially as specified.
Dated this 25th day of March 1899
By A. M. & Wm. Clark,
F. BIRD,
53, Chancery Lane, London, Chartered Patent Agents.