Improvements in and relating to Apparatus for Measuring Electric Currents.
Year: 1891

page_text: Date of Application, 14th Aug., 1891
Complete Specification Left, 14th May, 1892-Accepted, 3th Aug, 1892
PROVISIONAL SPECIFICATION.
Improvements in and relating to Apparatus for Measuring Electric
Currents.
I HERBERT WOODVILLE MILLER of 2 York Mansions, Earls Court S. W. in
the County of Middlesex Electrical Engineer, do hereby declare the nature of this
invention to be as follows :-
My invention relates to apparatus chiefly designed for measuring electric
currents.
By my invention I provide an improved device by means of which the quantity
or amount of electric current passing through a circuit may be accurately measured
and recorded or registered upon a suitable dial or dials.
In carrying my said invention into practice I provide an electrolytic bath of
suitable composition having a metallic anode and cathode which may be either
zinc, copper or silver or other suitable metal, and at a suitable distance between
them place
metallic conductor preferably in the form of a balanced cylindrical
wheel arranged to revolve freely in the liquid upon a horizontal axis, the anode
and cathode are so shaped as to embrace opposite portions on either side of the
cylindrical conductor leaving a suitable amount of clearance. The operation of
the apparatus is as follows:-On passing a current through the bath from the
anode to the cathode, metal is dissolved from the anode and is deposited on that
surface of the cylindrical conductor which it embraces, the metal thus deposited
upsets the equilibrium of the cylinder and causes it to turn towards the anode, at
the same time metal is dissolved off the opposite face of the cylinder and is
deposited on the cathode, the cylinder thus becomes heavier on one side and lighter
on the other and consequently revolves, and in so doing presents fresh surfaces to
the anode and cathode, the action being thus continued the cylinder continues to
revolve as long as current passes through the bath, the cylindrical conductor
becomes as it were a carrier to transfer the metal from the anode to the cathode,
itself remaining practically unaltered. The said cylinder or wheel is connected by
means of toothed gearing or in any other suitable manner with a dial or dials for
registering or recording the number of revolutions of the same and from this is
deducted the quantity or amount of electric current that has passed through the
apparatus. I sometimes prefer instead of using a cylinder to use a number of
discs placed at suitable distances upon a central shaft, and to groove out the
surfaces of the anode and cathode so as to fit between the discs leaving a suitable
amount of clearance with the object of obtaining an increased surface.
I sometimes form the revolving conductor of a different metal to the anode and
cathode preferably of some material upon which the bath has no direct action.
It is obvious that the anode will in course of time become eaten away and
will require to be augmented or renewed from time to time, to
meet this
requirement provide a simple means of reversing the positions of the anode and
cathode either by hand or automatically, in the latter case 1 find it advantageous
to form the anode and cathode in the shape of bars or rods arranged concen-
trically around the cylindrical conductor leaving a suitable amount of clearance, the
extremities of the said bars or rods are rigidly fixed at suitable intervals along
the periphery of two insulating discs, and are connected to the metallic cogs or
spokes of two small wheels arranged to run in mercury cups, thus forming a cage
or drum within which the cylindrical conductor is free to revolve. The said cogs
or spokes are suitably insulated from each other and are so arranged relatively to
the aforementioned bars or rods that those cogs or spokes which dip into the

page_text: mercury cup on one side of the drum are connected to bars on the right side and
those which dip into the mercury cup on the opposite side are similarly connected
to bars on the left side or vice versa, the said drum is supported on suitable bearings
so as to cause no friction to the internal cylinder. When a current is sent through
the apparatus by means of the mercury cups a certain number of bars on one side
will become anodes and an equal number on the other side will become cathodes,
these bars owing to the action of the current will become lighter and heavier
respectively, the drum of which these bars form a part will consequently revolve
and thereby present fresh bars to the action of the current, so that when a complete
revolution has taken place those bars which at first were anodes now become
cathodes, and vice versa, this action continues as long as the current passes.
In some instances I prefer to connect the anode and cathode by a metallic
conductor of low resistance, so that only a portion of the current passing in the
circuit flows through the apparatus. Although I have hereinbefore described
convenient and advantageous methods of carrying my said invention into practice
it is obvious that I can somewhat modify the construction of my apparatus without
however in any way departing from the nature of my said invention.
1
t 1901
COMPLETE SPECIFICATION.
Improvements in and relating to Apparatus for Measuring Electric
Currents.
I HERBERT WOODVILLE MILLER of 2 York Mansions, Earls Court, S. W. in
the County of Middlesex, 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:-
My invention relates to apparatus chiefly designed for measuring electric
currents.
By my invention I provide an improved device by means of which the quantity
or amount of electric current passing through a circuit, may be accurately measured
and recorded or registered upon a suitable dial or dials.
In carrying my said invention into practice I provide an electrolytic bath of
suitable construction such as sulphate of zinc or copper and in this bath, I place
one or more metallic anodes and cathodes made of zinc, or copper or silver or other
suitable metal and between them I place a metallic conductor preferably of the
same metal as the anodes and cathodes in the form of a balanced cylindrical wheel
arranged to revolve freely in the liquid upon a horizontal axis, the anodes and
cathodes are so shaped as to embrace opposite portions on either side of the
cylindrical conductor leaving a suitable amount of clearance. The operation of
the apparatus is as follows. Conductors from the outside of the bath are connected
to the anodes and cathodes and on passing an electric current through the bath
from the anode to the cathode, metal is dissolved from the anode and is deposited
on that surface of the cylindrical conductor which it embraces, the metal thus
deposited upsets the equilibrium of the cylinder and causes it to turn towards the
anode, at the same time metal is dissolved off the opposite face of the cylinder and
- deposited on the cathode, the cylinder thus becomes heavier on one side and lighter
on the other and consequently revolves, and in so doing presents fresh surfaces
to the anode & cathode, the action being thus continued the cylinder continues to
revolve as long as current passes through the bath, the cylindrical conductor
becomes as it were a carrier to transfer the metal from the anode to the cathode,
itself remaining practically unaltered. The said cylinder or wheel is connected by
means of toothed gearing or in any other suitable manner with dials for
recording the number of revolutions by which the amount of electric current passed
through the meter is recorded.

page_text: Another way of effecting the same result is shewn in Figs. I and II, where
a, a, represent a number of discs of metal placed at suitable distances upon a frame b
mounted on a shaft c, the frame & may be formed with an air tight chamber & the
object of which is to relieve the weight on the wheel bearings d by its buoyancy in
the bathe and are the anodes and cathodes arranged to fit between the discs a, a
leaving a suitable amount of clearance, by use of the discs a larger surface is
obtained; and are the terminals for the current to enter or leave the meter,
&k, are the conducting strips bringing the current to and from the anodes and
cathodes e & by contact with them. The anodes and cathodes e & fare mounted
on a disc, so arranged that by turning the disc round by hand the position of the
anodes and cathodes can be reversed, m is a worm wheel driving the shaft n,
connected with the recording dials, the disc is mounted on wheels o, o, so that it
can be turned when required." I sometimes form the revolving conductors or discs
of a different metal to the anodes and cathodes preferably of some material upon
which the bath has no direct action, such as aluminium. It is obvious that the
anodes will in course of time become eaten away and will require to be renewed, to
meet this requirement 1 provide a simple means of reversing the positions of the
anodes and cathodes automatically, Figs. 3 and 4 shew one way of doing this, I
form the anodes e and cathodes in the shape of bars or rods arranged concentrically
around the cylindrical conductor a or discs, leaving a suitable amount of clearance,
the extremities of the bars or rods e and are rigidly fixed at suitable intervals
along the periphery of two insulating discs and are connected by wires and k
to metallic cogs or spokes m arranged as a commutator dipping in mercury cups h;
thus forming a cage or drum within which the cylindrical conductor a or dises are
free to revolve, the parts of the commutators are insulated from each other and
connected each with a separate bar or rod, and so arranged that those parts of the
commutators which dip into the mercury cups on one side of the drum are connected
to bars on the right side and those which dip into the mercury cup on the opposite
side are similarly connected to bars on the left side or cice-rersi, the said drum or
cage is supported on suitable bearings d so as to cause no friction to the internal
cylinder or disce in revolving. When a current is sent through the apparatus by
means of the mercury cups a certain number of the bars or rods e will become
anodes and an equal number on the other side will become cathodes. These bars
owing to the action of the current will become lighter and heavier respectively,
the drum of which these bars or rods form a part will consequently revolve and
thereby present fresh bars to the action of the current so that when a half
revolution has taken place those bars which at first were anodes now become
cathodes and vice-versa.
Where it is not desirable to increase the size of the electrolytic bath anodes &
cathodes etc. in proportion to the current to be passed directly through the bath
such as for instance above 20 ampères I prefer to connect the electrolytic bath as a
shunt circuit to a conductor of low resistance preferably of the same metal as the
anodes & cathodes and to immerse this conductor in the same bath as the anodes
& cathodes to avoid errors due to change of temperature between the conductor &
the electrolytic bath by means of this shunt circuit only a known fraction of the
total current to be measured passes through the electrolytic bath.
Although I have hereinbefore described convenient methods of carrying out my
invention it is obvious that I can somewhat modify the construction of my
apparatus without however in any way departing from the nature of my invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
(1) In electrolytic meters the combination of revolving cylinders or discs placed
between anodes and cathodes with indicating devices for recording the number
of revolutions of the cylinders or discs.
(2) In electrolytic meters the combination of revolving cylinders or discs placed

page_text: between anodes and cathodes with indicating devices for recording the number of
revolutions of the cylinders or discs together with means of reversing the positions
of the anodes & cathodes either by hand or automatically substantially as described.
Dated this 14th day of May 1892.
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