Improvements in Instruments for Indicating and Registering the State of the Charge in Accumulators.
Year: 1890

page_text: Date of Application, 28th Aug., 1890
Complete Specification Left, 27th May, 1891-Accepted, 26th Sept., 1891
PROVISIONAL SPECIFICATION.
Improvements in Instruments for Indicating and Registering the
State of the Charge in Accumulators.
I, GASTON ROUX, of 51 Rue de Dunkerque, Paris, in the Republic of France,
do hereby declare the nature of this invention to be as follows:-
The object of my invention is the construction of an apparatus or instrument
indicating, in a continuous manner, the quantity of electricity stored in an electric
accumulator or other vessel, the indication being given by a hand or pointer moving
in front of a graded scale.
The apparatus is based upon the following principle that the density of an
electrolytic liquid varies, within certain limits, in a direct ratio to the quantity of
electricity stored in a chemical shape in an accumulator.
Consequently an apparatus indicating the average density of the totality of the
liquid will be sufficient for the deduction of the state of charge of an accumulator.
If the liquid was homogeneous a mere hydrometer would suffice but as it is not
such I obtain the desired result by means of a body immersed in the liquid & the
height of which is very nearly equal to the height of the said liquid. The
hydrostatic pressure upon the said body is the product of the average density of
the totality of the liquid mass by the volume of the displaced liquid. This volume
remaining constant the measure of the average density corresponds to that of the
hydrostatic pressure.
My apparatus is essentially composed of a cylindrical body with flat ends and
suspended at the top end, by a very fine rod. This body, the length of which is
slightly inferior to the height of the liquid contained in the accumulator, is
weighted and counterpoised in a suitable manner and its rod is attached at one end
of a very short lever which is in a horizontal position when the accumulator is
charged to saturation. On the same axle than that of the short lever, and making
with the said lever a convenient angle, is mounted a screwed rod provided with a
counterweight the shifting of which allows of the regulation of the instrument.
I make the above mentioned angle preferably 45 degrees which allows of a direct
reading for the hydrostatic pressure of the liquid is in direct ratio to tang. 45-
tang. a, value that can be read directly upon a horizontal scale, a being the angle
made by the short lever with the horizontal. Perpendicularly to the short
horizontal lever and mounted on the same axle is mounted an equilibrated hand or
pointer which is free to move in front of a horizontal scale divided into equal parts
or any other graded scale.
When the accumulator is discharged the hand points to zero of the scale; when
it is charged the hand is vertical.
When passing from a certain state of charge to another the density of the liquid
varies and the cylindrical body is displaced of a feeble quantity; but this displace-
ment may be made to be as small as desirable by altering the length of the short
lever.
The apparatus may be made to automatically record the indications by the
addition of the mechanism usually adopted in automatic recording instruments such
as a combination of one or more drums actuated by clockwork, a pen tracing a line
on a ruled band of paper, etc.
Asnières (Seine). Twenty-first August 1890.

page_text: COMPLETE SPECIFICATION.
Improvements in Instruments for Indicating and Registering the
State of the Charge in Accumulators.
-I GASTON ROUX, Electrician, of 51 Rue de Dunkerque, Paris, in the Republic of
France 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 :-
The object of my invention is the construction of an apparatus or instrument
indicating, in a continuous manner, the quantity of electricity stored in an electric
accumulator, the indication being given by a hand or pointer moving in front of a
graded scale.
The apparatus is based upon the following principle that the density of an
electrolytic liquid varies, within certain limits, in a direct ratio to the quantity of
electricity stored in a chemical shape in an accumulator.
Consequently an apparatus indicating the average density of the totality of
the liquid will be sufficient for the deduction of the state of charge of an
accumulator.
If the liquid was homogeneous a mere hydrometer would suffice but as it is not
such I obtain the desired result by means of a body immersed in the liquid and the
height of which is very nearly equal to the height of the said liquid. The hydro-
static pressure upon the said body is the product of the average density of the
totality of liquid mass by the volume of the displaced liquid. This volume
remaining constant the measure of the average density corresponds to that of the
hydrostatic pressure.
My apparatus is essentially composed of a cylindrical body with flat ends and
suspended at the top end, by a very fine rod. This body, the length of which is
slightly inferior to the height of the liquid contained in the accumulator, is
weighted and counterpoised in a suitable manner and its rod is attached at one end
of a very small lever which is in a horizontal position when the accumulator is
charged to saturation. On the same axle as that of the small lever, and making
with the said lever a convenient angle, is mounted a screwed rod provided with a
counterweight the shifting of which allows of the regulation of the instrument. I
make the above mentioned angle preferably 45 degrees which allows of a direct
reading for the hydrostatic pressure of the liquid is in direct ratio to tang. 45°---
tang. a, value that can be read directly upon a horizontal scale, and being the angle
made by the small lever with the horizontal. Perpendicularly to the small
horizontal lever and mounted on the same axle is mounted an equilibrated hand or
pointer which is free to move in front of a horizontal scale divided into equal parts
or any other graded scale. I divide the scale preferably, into one hundred parts.
"When the accumulator is discharged the hand points to the zero of the scale;
when it is charged the hand is vertical, pointing to 100.
When passing from a certain state of charge to another, the density of the liquid
varies and the cylindrical body is displaced of a feeble quantity; but this dis-
placement may be made to be as small as desirable by altering the length of the
small lever and therefore rendering practically nil the errors due to displacement.
The scale being divided into 100 parts each position of the hand correspond to the
state of charge in per cent. of the maximum charge.
The apparatus may be made to automatically record the indications by the
addition of the mechanism usually adopted in automatic recording instruments such
as a combination of one or more drums actuated by clockwork, a pen tracing a line
on a ruled band of paper, etc.
The apparatus may also be provided with electric contacts which on the hand
reaching one or the other of them cause the automatic ringing of a bell thereby
warning the attendant of the complete charging or discharging of the accumulators.

page_text: In the accompanying drawing:
A is the liquid of varying density.
B is a cylinder of circular or other shaped section, with flat top and bottom, and
equilibrated by the counterweight M.
C is a rod, or a suspension wire which transmits to the lever D the motions of the
cylinder B.
D is a balanced lever.
E is the axle of the lever D.
F is a counterweight used for regulating the vertical displacement of the
cylinder B.
G is a balanced hand or pointer.
His a scale graduated in equal divisions.
M is a moveable counterweight.
V is the accumulator or vessel.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what mauner the same is to be performed, I declare that what I
claim is:
1° The utilisation of the variation in the average density of the electrolytic
liquid contained in an accumulator for the indication of the quantity of electricity
stored in the said accumulator or vessel the said quantity of electricity being, at
every moment, within the limits of ordinary practice, directly proportional to the
average density of the said electrolytic liquid as hereinbefore described and
ascertained.
2° The combination of a body of cylindral or other shaped section with flat top
and bottom and occupying very nearly the whole of the height of the column of
liquid contained in an accumulator with a system of levers, counterweights, pointing
hand and gradation for the indication, recording and signalling at every moment
of the quantity of electricity stored in the said accumulator or vessel as herein before
described and ascertained, and illustrated.
London, Twenty-seventh May 1891.
J. A. BERLY,
43, London Wall, London, E.C.