IMPROVEMENTS IN METERS FOR MEASURING ELECTRIC CURRENTS
Year: 1881

page_text: "
LETTERS PATENT to Edward Griffith Brewer, of 33, Chancery Lane, in the
County of Middlesex, for an Invention of IMPROVEMENTS IN METERS FOR
MEASURING ELECTRIC CURRENTS." A communication from abroad by Thomas
Alva Edison, of Menlo Park, in the State of New Jersey, United States of
America.
PROVISIONAL SPECIFICATION left by the said Edward Griffith Brewer at
the Office of the Commissioners of Patents on the 19th October 1881.
EDWARD GRIFFITH Brewer, of 33, Chancery Lane, in the County of Middlesex.
IMPROVEMENTS IN METERS FOR MEASURING ELECTRIC CURRENTS."
A coin-
munication from abroad by Thomas Alva Edison, of Menlo Park, in the State of
New Jersey, United States of America.
This Invention relates to the electro plating or metal depositing cell electric meter
for measuring the amount of electrical energy consumed in a system of electric
lighting, in which meter the metal is taken from one electrode of the cell and is
deposited upon the other by the action of the current. This depositing cell is
arranged so that only a small part of the current will pass through it, the total
current being determined by the measurement of a definite fractional portion
thereof.
The object of the first part of the Invention is to produce an electric meter of
this character which will produce a correct deposit of metal by the use of a much
weaker current (or smaller portion of the entire current) than is possible with the
employment, as heretofore practiced, of simple copper electrodes, thus causing a
considerable saving in electrical energy.
This is accomplished by using amalgamated electrodes in the depositing cell.
The electrodes preferred for this purpose, and which are the most accurate, are made
of metallic zinc placed in a strong solution of sulphate of zinc. It is preferable that

page_text: such electrodes before being used in the meter should have a heavy coating of
deposited zinc placed on them by the action of an electric current, which zinc will
be thoroughly amalgamated while being deposited.
Plates thus prepared are precisely alike and give accurate results.
Other metals which can be amalgamated, such as cadmium, lead, and tin, are
capable of being used in this connection when immersed in solutions of their salts
not acting upon the mercury, such as the sulphate of cadmium and acetate of lead,
but none are as accurate as zinc treated as described.
The depositing cell meter is arranged in a shunt from one of the conductors of a
house or other consumption circuit, a resistance being placed in the line to shunt a
definite small portion of the entire current through the meter.
A wire resistance is placed in the same shunt as the depositing cell, and is
arranged to compensate for the effect of changes in temperature or the resistance
of the cell. The wire being increased in resistance by a rise of temperature, and
the cell proportionately decreased, and a fall of temperature having exactly the
opposite effect on the wire and cell, the total resistance of the shunt will always
be the same, and consequently the same fraction of the current will always pass
through it.
Two or more depositing cells may be used instead of one cell in the same shant,
or two cells may be placed in separate shunt circuits, so that one will act upon the
other.
prevent the establishing by the cell of a counter current and the re-com-
position of the solution when no lamp is on and no current is flowing through the
house or consumption circuit, a device is provided for automatically breaking the
shunt when the circuit of the last lamp is broken, and for closing such shunt when
the first lamp circuit is completed. This device may consist of an electro-magnet
placed directly in the house or consumption circuit, or in a multiple arc circuit there-
from, or in a shunt from one of the conductors of the consumption circuit, and
operating a lever arranged to make and break the meter shunt at its front
contact; or this magnet may be the resistance around which the meter shunt is
placed.
The object of another part of this Invention is to produce a vebermeter of the
above described class, which will have the temperature within the enclosing case so
automatically regulated that the solution in the electrolytic cells cannot reach the
freezing point, which low temperature would render the cells inoperative, and a
further object is to produce a simple and cheap construction of cells for use in
vebermeters of this character which will not necessitate the employment of glass
jars.
The first object is accomplished by placing in the box which encloses the meter
a carbon or metallic resistance, situated in a space common to both cells of the
meter, if more than one cell is used, and arranged in a derived circuit in which is
placed an automatic thermo circuit regulator, which closes the circuit when a
definite low temperature is reached (for instance, ten degrees above the freezing
point of the solution contained in the cell). The carbon resistance is heated by
the passage of the current, but not sufficiently to be destructive of the same, and
the temperature of the meter is maintained above the freezing point of the
solution.
The thermo circuit regulator may be a spring carrying a lever on its free end,
which lever is thrown by the contraction of the spring against a contact point,
completing the circuit in which the carbon resistance is placed.
When the temperature rises the spring expands and the circuit is broken, and it
is closed again by the fall of the temperature. The plates of the electrolytic cells
are maintained at a definite distance apart by simple means.
For this purpose there are placed between the plates blocks of non-conducting
material, which are of a definite thickness, representing the distance it is desired to
keep the plates apart, and such plates are removably clamped upon the blocks by

page_text: means of a screw, also of non-conducting material, hard rubber being suitable for
this purpose.
The meter is preferably provided with two cells, one of which, having its plates
placed farther apart, and having a smaller proportion of the current shunted through
it, will deposit only a small proportion of what the first cell deposits, and may be
used as a check upon the first cell.
To accomplish the second object mentioned above (the production of a simple
cell without the use of glass) the jar is made of copper, and within it is placed
removably upon a block of non-conducting material an inner and smaller cylinder
of copper. The jar is connected to one pole and the inner cylinder to the other, the
deposition taking place upon said inner cylinder. The jar. has a removable cap,
which allows the inner cylinder to be removed and replaced at will.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Griffith Brewer in the Great Seal Patent Office on the
19th April 1882.
EDWARD GRIFFITH BREWER, of 33, Chancery Lane, in the County of Middlesex.
" IMPROVEMENTS IN METERS FOR MEASURING ELECTRIC CURRENTS."
A com-
munication from abroad by Thomas Alva Edison, of Menlo Park, in the State of
New Jersey, United States of America.
This Invention relates to the electro plating or metal-depositing cell electric meter
for measuring the amount of electrical energy consumed in a system of electric
lighting, in which meter the metal is taken from one electrode of the cell and is
deposited upon the other by the action of the current. This depositing cell is
arranged so that only a small part of the current will pass through it, the total
current being determined by the measurement of a definite fractional portion
thereof.
The object of the first part of the Invention is to produce an electric meter of
this character which will produce a correct deposit of metal by the use of a much
weaker current (or smaller portion of the entire current) than is possible with the
employment as heretofore practiced of simple copper electrodes, thus causing a
considerable saving in electrical energy.
This is accomplished by using amalgamated electrodes in the depositing cell.
The electrodes preferred for this purpose, and which are the most accurate are
made of metallic zinc placed in a strong solution of sulphate of zinc. It is
preferable that such electrodes before being used in the meter should have a heavy
coating of deposited zinc placed on them by the action of an electric current, which
zinc will be thoroughly amalgamated while being deposited.
Plates thus prepared are precisely alike, and give accurate results.
Other metals which can be amalgamated, such as cadmium, lead, and tin, are
capable of being used in this connection when immersed in solutions of their salts
not acting upon the mercury, such as the sulphate of cadmium and acetate of lead,
but none are as accurate as zinc treated as described.
The depositing cell meter is arranged in a shunt from one of the conductors of
a house or other consumption circuit, a resistance being placed in the line to shunt
a definite small portion of the entire current through the meter.
A wire resistance is placed in the same shunt as the depositing cell, and is
arranged to compensate for the effect of changes in temperature on the resistance
of the cell. The wire being increased in resistance by a rise of temperature and
the cell proportionately decreased, and a fall of temperature having exactly the
opposite effect on the wire and cell, the total resistance of the shunt will always be
the same, and consequently the same fraction of the current will always pass
through it.
Two or more depositing cells may be used instead of one cell in the same shunt,
or two cells may be placed in separate shunt circuits, so that one will act upon the
other.
To prevent the establishing of the cell of a counter current and the recomposition
of the solution when no lamp is on and no current is flowing through the house or
consumption circuit, a device is provided for automatically breaking the shunt
when the circuit of the last lamp is broken, and for closing such shunt when the
first lamp circuit is completed. This device may consist of an electro magnet placed
directly in the house or consumption circuit, or in a multiple arc circuit therefrom,
or in a shunt from one of the conductors of the consumption circuit, and operating

page_text: a lever arranged to make and break the meter shunt at its front contact. Or this
magnet may be the resistance around which the meter shunt is placed.
The object of another part of this Invention is to produce a vebermeter of the
above described class which will have the temperature within the enclosing case
so automatically regulated, that the solution in the electrolytic cells cannot reach
the freezing point, which low temperature would render the cells inoperative, and a
further object is to produce a simple and cheap construction of cells for use in
vebermeters of this character, which will not necessitate the employment of glass
jars.
The first object is accomplished by placing in the box which incloses the meter a
carbon or metallic resistance, situated in a space common to both cells of the meter,
if more than one cell is used, and arranged in a derived circuit in which is placed
an automatic thermo circuit regulator, which closes the circuit when a definite low
temperature is reached (for instance, ten degrees above the freezing point of the
solution contained in the cell). The carbon resistance is heated by the passage of
the current, but not sufficiently to be destructive of the same, and the temperature
of the meter is maintained above the freezing point of the solution.
The termo circuit regulator may be a spring carrying a lever on its free end,
which lever is thrown by the contraction of the spring against a contact point,
completing the circuit in which the carbon resistance is placed.
When the temperature rises the spring expands, and the circuit is broken, and it
is closed again by the fall of the temperature. The plates of the electrolytic cells
are maintained at a definite distance apart by simple means.
For this purpose there are placed between the plates blocks of non conducting
material which are of a definite thickness, representing the distance it is desired to
keep the plates apart, and such plates are removably clamped upon the blocks by
means of a screw also of non-conducting material, hard rubber being suitable for
this purpose.
The meter is preferably provided with two cells, one of which having its plates
placed farther apart, and having a smaller proportion of the current shunted
through it, will deposit only a small proportion of what the first cell deposits, and
may be used as a check upon the first cell.
To accomplish the second object mentioned above (the production of a simple cell
without the use of glass) the jar is made of copper, and within it is placed
removably upon a block of non conducting material an inner and smaller cylinder
of copper. The jar is connected to one pole, and the inner cylinder to the other,
the deposition taking place upon said inner cylinder. The jar has a removable cap
which allows the inner cylinder to be removed and replaced at will.
The first part of this Invention is illustrated in Figure 1 of the Drawings, which
is a diagrammatic view of a meter and connections.
1, 2, are the conductors of the house or consumption circuit, and L lamps or
other translating devices placed in multiple arc or cross circuits. Ris resistance in
either conductor 1 or 2. 3, 4, represent the meter shunt. M is the depositing cell
forming the meter, having amalgamated zinc electrodes E, E¹, and a solution of
sulphate of zinc S. R¹ is the wire resistance in shunt 3, 4, to compensate for the
varying resistance of S.
A is the electro magnet in one of the conductors 1, 2,
operating lever B placed in shunt 3, 4, and making and breaking said shunt at
contact c.
The second part of the Invention is shown in Figures 2, 3, and 4, of which
Figure 2 is a view showing the arrangement of the cells and carbon resistance.
Figure 3, a separate view of the plates of one cell and the stopple connections,
and
Figure 4, a vertical section of the modified construction of cell.
1, 2, are the main conductors in shunt circuits, from which are arranged the two
electrolytic cells A, B. The resistances a, b, (preferably of German silver), shunt
portions of the current through the cells. In the shunt circuit of the cells are fine
wire resistances a, b, which counterbalance the increase and decrease in the con-

page_text: ductivity of the cells, due to variation of the temperature. The plates C, D, of the
cells are separated by non conducting blocks or strips c, and are clamped removably
upon such blocks or strips by screws d of non conducting material.
The plates of cell B are placed farther apart than those of A, and the resistance b
is made less than a, so that the deposit in cell B is made in proportion to that in A.
For instance, B may be arranged to deposit in six months the same amount A will
deposit in one month, and B can be examined at the end of that time, and used to
check the accounts based on the monthly examination of A.
In the meter box is placed the carbon resistance E, which is made of carbonized
paper or of other suitable material or of a suitable metal.
This carbon resistance is in the derived circuit 3, 4, in which is also placed the
lever F and contact e. The lever F is carried by the free end of a coiled spring G,
which is adjusted to throw F against e when a certain low temperature is reached,
as, for instance, ten degrees above the freezing point of the solution.
In the modified form of cell not employing glass, H, Figure 4, is the copper
vessel in which is placed the copper cylinder I resting removably on a block F of
non conducting material; J is the removable cover, and g, h, are the connections
with the outer and inner cylinders. It is obvious that instead of carbon resistance
exposed to air an incandescent electric lamp containing a filament of carbon may
be used to heat the electrolytic cells.
WHAT IS CLAIMED IS,-
First. In an electric meter an electro depositing cell provided with amalgamated
metallic electrodes.
Second. In an electric meter an electro depositing cell having amalgamated zinc
electrodes.
Third. The combination with an electric circuit having a definite and known
resistance of a shunt circuit around such resistance, containing one or more electro
depositing cells provided with amalgamated metallic electrodes for determining the
current in the main circuit, substantially as set forth.
Fourth. The combination with an electric circuit having a definite and known
resistance of a shunt circuit around such resistance, containing one or more electro
depositing cells provided with amalgamated zinc electrodes for determining the
current in the main circuit, substantially as set forth.
Fifth. A meter for measuring the current in any electric circuit, consisting of a
known resistance in such circuit, around which is a shunt circuit containing one or
more electro depositing cells with amalgamated metallic electrodes and resistances
for compensating for the effect of changes of temperature on the resistance of such
cells, substantially as set forth.
Sixth. The combination with an electro depositing cell acting as a meter of a
circuit closer and breaker, arranged to break the meter circuit when no translating
devices are in operation and to close such meter circuit when a single translating
device is put in operation, substantially as set forth.
Seventh. The combination with an electric circuit having a definite and known
resistance of one or more electro depositing cells arranged in a shunt around such
resistance, and an electro magnet in the main circuit or in a shunt or multiple arc
circuit therefrom operating to open and close the meter shunt, substantially as and
for the purpose set forth.
Eighth. In an electrolytic cell vebermeter a carbon or other resistance heated
by an electric current, and arranged in proximity to the cell or cells for main-
taining the temperature of the solution above the freezing point, substantially as
set forth.
Ninth. In an electrolytic cell vebermeter the combination of a carbon or other
resistance arranged in proximity to the cell or cells and an automatic thermo
circuit regulator for making and breaking the circuit of the resistance, substantially
as set forth.
Tenth. In an electrolytic cell vebermeter the combination of a carbon or other

page_text: resistance arranged in proximity to the cell or cells and an automatic thermo
circuit regulator composed of a spring and contact lever for making and breaking
the circuit of the carbon or other resistance, substantially as set forth.
Eleventh. In an electrolytic cell vebermeter the plates of the cell retained a
definite distance apart by means of non-conducting blocks or strips, and removably
clamped upon such blocks or strips, substantially as set forth.
Twelfth. An electrolytic cell for vebermeters, composed of a copper vessel and
a removable copper cylinder placed in such vessel and insulated therefrom, the
connections being made with such vessel and cylinder, substantially as set forth.
Thirteenth. The method of maintaining the solution of an electrolytic cell above
the freezing point, consisting in heating the same from a carbon or other resistance,
the circuit of which is made or broken automatically by the fall and rise of the
temperature, substantially as set forth.
In witness whereof, I, the said Edward Griffith Brewer, have hereunto set
my hand and seal, this Eighteenth day of April, in the year of our Lord
One thousand eight hundred and eighty two.
E. G. BREWER.
(LS.)