Improvements in Electric Meters.
Year: 1891

page_text: Date of Application (in United Kingdom), 5th Oct., 1891
Complete Specification Left, 5th Oct., 1891-Accepted, 21st May, 1892
COMPLETE SPECIFICATION.
Improvements in Electric Meters.
I, EMILE CHARLES GRASSOT, of 45 Rue Saint-Sebastien, Paris, in the
Republic of France, Electrical 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:-
The electric meter which forms the subject of this invention is represented in
the accompanying drawing to which I refer in the following description.
In this drawing
Figure 1 is a front view partly in section of the improved meter, and
Figure 2 a side view of the same.
My electric meter comprises a vessel A containing a solution of a metallic salt,
an anode b and a cathode à of the same metal as the salt of the solution.
The cathode is formed of a metallic strip a arranged in the interior of the
vessel A, and connected with the negative pole.
The anode is formed of a wire badapted to descend freely in a tube B of glass
or other insulating material and dipping about three millimetres into the solution.
This wire is pointed at its lower end, and bears with its' point upon the upper
plane surface of a support C of glass or other insulating material.
C
The tube B and the support C are suitably fixed to the metallic cover D which
closes the vessel A. This cover carries mechanism comprising a drum d, against
which the wire 6 is lightly pressed by means of a roller e and an adjustable
weight f.
For a short distance above and below the drum d the glass tube is interrupted so
as to leave the wire bare.
Upon the axis of the drum d is provided a hand g adapted to turn in front of a
dial which is suitably graduated.
A pinion and wheel transmit the movement of the drum to a second parallel axis
upon which is provided a hand also adapted to turn in front of a suitably
graduated dial.
g
The proportion between the pinion and the wheel is such that while the hand
makes one complete revolution the hand & advances upon its dial one division. The
number of hands can be increased as in the case of other meters.
Although the dimensions of the vessel A can be varied, it is expedient to
construct the latter so as to contain about 500 grammes of the metallic solution.
This solution consists of about 100 grammes of nitrate of silver or cyanide of
silver per litre.
The metallic anode is made of silver wire of about 0-5 millimetres diameter.
When the current flows through the apparatus the metal dissolves from the
anode 6 and is deposited on the cathode a. The wire anode 6 remains pointed and
as it diminishes in length descends at a rate proportional to the intensity of the
surrent passing.
This descending movement is transmitted to the drum d against which the wire b

page_text: is pressed, and is therefore shown by the hand g which moves round in front of its
dial.
The number of turns of this hand g is indicated by the hand h and so on.
When using this meter in an electric lighting circuit it is sufficient to arrange the
apparatus as a shunt to a very small resistance through which the main current
passes, so as to allow about one-thousandth of the current which it is desired to
measure to pass through the said apparatus.
I wish it to be clearly understood that I do not limit myself with regard to the
forms and dimensions of this meter, the parts of which can be adjusted, mounted
and fixed in any suitable manner.
The materials employed may also be of any kind adapted to appropriately
operate the parts.
The above stated proportions for the metallic solution may likewise be varied,
and other metallic salt employed.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that
what I claim is :-
First. For measuring the quantity of electricity supplied to an electric circnit,
the arrangement in the circuit of an apparatus formed of a vessel containing a
metallic solution, an anode and a cathode of the same metal as the salt of the said
solution, the anode consisting of a wire free to descend in proportion as it is used
up by the transference of its metal to the cathode during the action of the current,
the said wire being consumed proportionately to the intensity of the current passing
and therefore descending at a rate proportional to this intensity, as hereinbefore set
forth with reference to the accompanying drawing.
Second. In an electric meter the arrangement in an insulating tube B of a
metallic anode 6 extending beyond the said tube only a very small distance (about
three millimetres for example), the point of the said anode resting or bearing
upon a fixed insulating support C, in combination with a metallic cathode a arranged
in a vessel A containing a metallic solution, the said anode 6 descending in propor-
tion to the transference of its metal to the cathode a under the action of the
electric current, as hereinbefore set forth with reference to the accompanying
drawing.
Third. In an electric meter the combination of a metallic anode 6 adapted to
descend in proportion to the transference of its metals to a cathode a under the
action of an electric current, with a drum d against which the said anode is pressed
by a rollere so as to cause the drum to turn when the said anode descends and
indicates upon a dial by its hand 9, the quantity of electricity which it is desired to
measure, the drum & being combined with a greater or less number of dials, as
hereinbefore set forth with reference to the accompanying drawing.
Fourth. The electric meter constructed and operating substantially as herein-
before described with reference to the accompanying drawing.
Dated this 5th day of October 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.