IMPROVEMENTS IN ELECTRICAL METERS
Year: 1882

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LETTERS PATENT to Thomas John Handford of 42 Southampton Buildings in
the County of Middlesex Patent Agent for an Invention of "IMPROVEMENTS
IN ELECTRICAL METERS Communicated to him 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 Thomas John Handford at
the Office of the Commissioners of Patents on the 19th September 1882.
"
THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex Patent Agent IMPROVEMENTS IN ELECTRICAL METERS " a communi-
cation to me from abroad by Thomas Alva Edison of Menlo Park in the State of
New Jersey United States of America
This Invention relating to Electrical Meters has reference to the employment of
what is termed "an electrolytic motor" in which a body capable of rotation is
placed between the electrodes of an electrolytic cell forming part of the circuit
between them and is caused to revolve by the increase of weight occasioned by
deposition on the side adjacent to the anode and the decrease of weight on the
other side caused by the removal of metal therefrom.
The number of such revolutions is automatically indicated or registered and the
amount of deposition and consequently the quantity of current passing through
the cell is thus determined.
In carrying out the Invention an ordinary electrolytic cell is employed, placed
preferably in a shunt circuit from the main line whose current is to be measured
although it may if desired be placed directly in such main line. In the centre of
such cell is placed a hollow metal cylinder with open ends, preferably made of
amalgamated zinc. This cylinder is supported on a shaft made of insulating
material and having bearings on suitable standards. Within the cylinder radiating
from the axis are a number of flat paddle blades also preferably of amalgamated.
zinc which necessarily revolve with the cylinder within the liquid of the cell
which liquid offers considerable resistance to the passage of such blades. The
anode and cathode of the cell which are preferably amalgamated zinc plates are
suspended one on each side of the cylinder.

page_text: The current in passing between these electrodes necessarily selects the cylinder
as a portion of its path the resistance of such cylinder being much less than that
of the liquid; and the metal from the anode is deposited on the adjacent side of the
cylinder and thus increasing the weight of that side, the cylinder is caused to
revolve. On the opposite side the metal is removed from the cylinder and deposited
on the cathode and thus one side of the cylinder being always heavier than the
other a continuous rotation is produced.
A registering apparatus is placed at a convenient point and an arm is attached
to the axis of the cylinder which once during each revolution of the cylinder
moves such registering apparatus thus recording the number of revolutions. An
additional dial plate may be provided on which this arm will indicate fractions of
a revolution. Or in lieu of this arrangement of registering apparatus the cylinder
may be provided with means acting at a certain point in its revolution to close or
open a circuit whose closure or opening causes the operation of the registering or
indicating device. As such number of revolutions depends on the amount of metal
placed on and removed from the cylinder and this in turn depends on the amount
of current passing in the circuit the last is easily determined.
The main portion of the work done consists in turning the paddle blades in the
liquid and consequently the friction of the shaft of the cylinder in its bearings
becomes an unimportant factor and any variations therein need not be considered
in the calculation.
A wire resistance should be placed in the shunt which contains the cell such
resistance being affected oppositely by changes in temperature to the liquid in the
cell, and therefore compensating for changes in the resistance of the said liquid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas John Handford in the Great Seal Patent Office on the
16th March 1883.
THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex Patent Agent "IMPROVEMENTS IN ELECTRICAL METERS " A communi-
cation to me from abroad by Thomas Alva Edison of Menlo Park, in the State of
New Jersey, United States of America
The said Invention relating to electrical meters, has reference to the employment
of what is termed an " electrolytic motor" in which a body capable of rotation is
placed between the electrodes of an electrolytic cell, forming part of the circuit
between them, and is caused to revolve by the increase of weight occasioned by
deposition on the side adjacent to the anode, and the decrease of weight on the
other side caused by the removal of metal therefrom. The number of such
revolutions being automatically indicated or registered the amount of deposition
and consequently the quantity of current passing through the cell is thus
determined.
It has previously been proposed to use apparatus of this description as an
electrical meter, but the object of the present Invention is to so construct and
arrange the apparatus that a more efficient and reliable meter shall be produced,
than has been attainable by the arrangements of electrolytic motors heretofore
proposed for the purpose.
In carrying out the Invention in order to effect this object, an amalgamated
metallic cylinder is used mounted on insulated bearings and having paddles offering
a definite resistance to the revolution of the cylinder and electrodes of an
amalgamated metal immersed with the said cylinder in the liquid of the electrolytic
cell (necessarily a solution of the salt of the metal) and in combination with the
motor is employed registering apparatus operating in a manner fully hereinafter
described.
And in order that the said Invention may be perfectly understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the accompanying sheet of drawings the same letters of
reference indicating corresponding parts in all the figures.
Figure 1 is a sectional view of the meter with a diagram of the circuits.
Figure 2 a sectional elevation showing the paddle blades and the insulating
supports for them and the cylinder and
Figure 3 is a view illustrating a modification of the registering apparatus
A is the cell which contains the anode a and cathode c each being preferably an
amalgamated plate of zinc. Such electrodes are in a shunt circuit 3. 4 from the
multiple arc circuit 5, 6. which is the house circuit, whose current is to be
measured and which is derived from the main line 1. 2 A resistance R is placed
in conductor 6 so that the desired proportion of current may be diverted into the
shunt B is the metal cylinder placed between the electrodes and revolving on a
shaft which is preferably of glass with pointed ends. C. C are standards
preferably of hard rubber, through which pass hard rubber pins d, d held by hard
rubber screws e, e,.
The pins d d have cavities, which form bearings for the ends
of shaft b. The paddle blades D D extend from the shaft b to the inner surface
of the cylinder. The cell is filled with liquid which assuming the electrodes and
cylinder to be composed of amalgamated zinc is a solution of sulphate of zinc, and
the paddle blades revolve in such liquid.
An arm E attached to shaft b strikes the arms ff and moves the pointer g thus
recording the number of revolutions on a dial plate. Another dial plate F may be
provided on which the arm E will record fractions of a revolution.

page_text: In the form shown in Figure 3 the arm E strikes one of the arms h h at each
revolution of the cylinder, forcing together the contact springs, i, i, and closing a
multiple arc circuit 7. 8 through a magnet H This moves the armature j, and
pawl arm which work the registering apparatus illustrated by the train of
gearing l.
As the number of revolutions depends on the amount of metal placed on and
removed from the cylinder and this in turn depends on the amount of current
passing in the circuit, the last is easily determined
The main portion of the work done consists in turning the paddle blades in the
liquid and consequently the friction of the shaft of the cylinder in its bearings
becomes an unimportant factor and any variations therein need not be considered
in the calculation.
A wire resistance R¹ should be placed in the shunt 3. 4 which contains the cell,
such resistance being affected oppositely by changes in temperature to the
liquid in the cell, and therefore compensating for changes in the resistance of the
said liquid.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is.
The electrolytic meter composed of an amalgamated metallic cylinder, mounted
on insulated bearings, and having paddles offering a definite resistance to the
revolution of the cylinder and electrodes of an amalgamated metal immersed with
the said cylinder in the liquid of the electrolytic cell, in combination with registering
apparatus operating substantially as hereinbefore described.
In witness whereof I the said Thomas John Handford have hereunto set my
hand and seal this fifteenth day of March in the year of our Lord One
thousand eight hundred and eighty three.
TH J. HANDFORD. (L.S.)