Electric Meters.
Year: 1898

page_text: Date of Application, 29th Aug., 1898-Accepted, 7th Jan., 1899
Electric Meters.
I, BENJAMIN JOSEPH BARNARD MILLS, of 23, Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention
(a communication to me from Thomas Alva Edison, residing at Llewellyn Park, in
the County of Essex and State of New Jersey, in the United States of America,
Inventor) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The invention relates to an improved registering electric meter, which is of
simple construction and of the highest accuracy.
In the drawings, Figure 1 is a front elevation of the meter with the door of
the meter case open: Figure 2 is a side elevation and partial section of the meter;
Figure 3 is a plan view of the scale beam and clockwork mechanism of the meter;
Figure 4 is an elevation of the clockwork mechanism; Figure 5 is a side elevation
and partial section at one end of the scale-beam; Figure 6 is a sectional view of
one of the electrolytic cells; Figure 7 is a diagram showing the electrical con-
nections of the meter; and Figure 8 is a view illustrating a method of securing a
continuous current for operating the meter from an alternating current circuit.
In all of the above views, corresponding parts are represented by the same
numerals of reference.
therein.
1 is a case, having a door 2 provided with a glass-covered opening
The parts of the meter are carried by a board 4 or other insulating backing within
the case 1. 5 is a three-arm bracket, carrying on two of its arms glass jars 6, 7,
each of such jars having within it a fixed electrode 8 and a movable electrode 9.
These electrodes are preferably cylindrical and open-ended. The fixed electrode 8
is carried by posts 10, from which it is insulated, and by adjustment of the connections
between the electrode and these posts the fixed electrode can be accurately centered
with relation to the movable electrode and independent of the enclosing glass jar.
The glass jars are preferably dipped exteriorly a number of times in acetate of
amyl-collodion, the jar being dried after each dipping. This forms a thin, tough
The
coating on the outside of the jar, so as to prevent leakage if the jar cracks.
electrodes 8, 9, are made preferably of pure metallic zinc, which is amalgamated,
and they are immersed in a solution 11 of a salt of the metal; in this instance,
sulphate of zinc. A solution of from ten to twenty-five per cent. of sulphate of
zinc in distilled water gives good results. If desired, the electrodes may be made
of any other suitable metal, such, for example, as pure silver immersed in a
solution of nitrate of silver or in a solution of cyanide of silver and cyanide of
potassium or of pure copper immersed in a solution of sulphate of copper; or
instead thereof silver electrodes may be used with a solution giving chlorine by
electrolysis, as a solution of hydrochloric acid, whereby, instead of the metal being
deposited, chloride of silver is formed on one electrode and when the current is

page_text: reversed the other electrode is coated with chloride of silver, while the electrode
first chloridized is reduced to metallic silver, no metal being deposited from the
solution. The solution 11 is covered with a layer 12 of a stable, inorganic, non-
miscible liquid, such as a mineral oil, of which pure paraffine oil is the preferred
example. A thickness of one eighth of an inch of this layer will be sufficient.
The presence of this layer prevents any evaporation or creeping of the solution,
so that the resistance of the solution and its rate of deposition remain always
constant.
The movable electrode 9 of each cell is carried by a wire 13 from a ring of ivory
or other insulating material 14, hung from a stirrup 15, which in turn is hung by
a knife-edge 16 from a scale-beam 17. The scale-beam is carried on knife-edges 18
on standards 19. The two movable electrodes being carried by opposite ends of
the scale-beam counterbalance each other. 20 is an arm depending from the
scale-beam in line with knife edges 18, and carries on its lower end an adjustable
weight 21, which resists the movement of the scale-beam from its central position.
22 and 23 are plates supported by the bracket 5 and carrying a suitable register-
train 24. The shafts of the register-train carry indexes 25, which cooperate with
dials 26 to register the current. The train is driven by a weight 27 or a suitably
arranged spring. The fast or escapement shaft 28 of the train carries an escape-
ment arm 29, which is made as long as practicable and has at its ends two pallets 30
and 31 arranged at different distances from the shaft 28. These pallets coöperate
with a pallet stud 32 carried by the scale-beam above its knife-edge.
beam in oscillating will carry the pallet-stud 32 from beneath one or the other of
the pallets and into the path of the other pallet, as will be under-
stood. Thé escapement shaft 28 carries a crank-pin 33. which works in
a fork at the lower end of the pivoted lever 34, which lever carries at
its upper end a contact bar 35, whose contact surface is preferably gold-plated.
This contact bar 35 is moved by the escapement into and out of contact with
springs 36 and 37. These springs approach each other at their free ends, leaving
a small gap between, and each movement of the escapement carries the contact
piece from one set of springs to the other. The ends of the springs where they
make contact with the contact piece are also preferably gold plated.
The scale-
An electrical connection of definite and uniform resistance is made from the
base to the pivoted-lever 34 by means of a flexible and non-elastic strip of metal leaf 38.
The springs 36 and 37 are mounted upon blocks of insulating material 39 and are
connected with wires 40 and 41. Connections of definite and uniform electrical
resistance are made with the movable electrodes by means of flexible, non elastic
strips of metal foil 42 and 43, which are connected with extensions from the
wires 13 which support the movable electrodes. In this way the circuits through
the meter have a definite electrical resistance at all times, no circuit connection
being carried through a movable joint or being dependent upon surface contact,
except in the case of the reverser. The wires 13, which support the movable
electrodes, are coated, as are the glass jars 6 and 7, with a number of layers of
acetate of amyl-collodion from the point of their connection with the movable
electrodes to a point above the surface of the liquid, so as to insulate them and
prevent any electrolytic action upon these wires or at their connections with the
electrodes.
The meter with a current-reverser such as I have described will be connected
around a resistance 44, made preferably of German silver. This resistance is
connected in the circuit of one of the main conductors 45 of the circuit whose
current is to be measured, such main conductor being broken within the meter and
the resistance being located in the break. The other main conductor, 46, passes
directly through the meter. The resistance 44 may be arranged in flat form around
the inside of the case over spools 47. The two ends of the resistance are
connected with the ends of the break in the main 45, while from the centre of the
resistance a connection 48 is made with the resistance, which leads through a

page_text: temperature-compensating spool 49 to a connection with the movable electrode of
one of the cells.
An incandescent lamp 50 is arranged in a branch circuit
between the two main conductors, and its circuit is controlled by a thermostat 51,
which closes the circuit to the lamp when the temperature approaches the freezing
point of the solution, thus preventing the freezing of the solution.
Referring to Figure 7, in which the electrical connections are illustrated, it will
be seen that the two electrolytic cells are connected in series around one-half of the
resistance 44 or the other half of the resistance 44, according to the position of
the current-reversing contact 35, and this arrangement enables a current-reverser
to be used with only one contact point in operation at any time and which reverses
the current by a simple movement from one contact point to another contact point.
While it is preferred to use this simple current-reverser, it is evident that the other
features of the meter might be used with other forms of current-reverser. It will
be observed that when the current passes through the electrolytic cells, the scale-
beam being tipped in one direction, the elevated movable electrode will have metal
deposited upon it, or will become heavier, while the depressed movable electrode
will have metal stripped from it, or become lighter. This process continues until
the elevated electrode overbalances the depressed electrode sufficiently to disengage
the pallet-stud 32 from the pallet 30 or 31 which is in contact with it, when the
escapement will be released and the current will be reversed through the meter.
This reversal of current will produce the reverse operation, and the scale-beam will
move in the opposite direction. These movements are registered on the dials and
correspond with uniform current values.
When it is desired to utilize the improved meter for measuring alternating
currents, it is preferred to generate by means of such alternating currents a direct
current proportional to the alternating current and which direct current will be
used to effect the action in the electrolytic cells. This principle is illustrated in
Figure 8, in which 52 represents one of the main conductors of a circuit, which is
reduced in cross-section so as to generate heat at the point 53, which heat is utilized
to raise the temperature of the alternate junctions of a thermopile 54, from
the centre and ends of which are taken wires for conveying a continuous current
through the meter.
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:
-
1) An electrolytic registering meter having a scale-beam operated by electrolytic
action, a power-driven escapement controlled by the scale-beam, and a current-
reverser and register operated by said power escapement, substantially as described.
2) In an electrolytic meter, an electrolytic cell whose solution is covered with a
stable. inorganic, non-miscible liquid, substantially as described.
3) In a registering electrolytic meter, the two-point current reverser operating
to shunt the meter first around one-half of a resistance and then around the other
half, substantially as described.
4) In a registering electrolytic meter, the flexible, non-elastic, metallic leaf
strips for establishing permanent electrical connections with movable parts,
substantially as described."
5) A registering electrolytic meter having two cells whose movable electrodes are
carried by the opposite ends of a scale-beam, such movable electrodes being in-
sulated from the scale-beam and having permanent connections with the circuit
through flexible metallic connections, substantially as described.
6) In an electrolytic meter, the coating of the glass jars with acetate of amyl-
collodion to avoid leakage from cracking, substantially as described.
7) In an electrolytic registering meter having electrolytic cells and fixed and
movable electrodes, the supporting of the fixed electrodes independent of the cells,
so that they may be centered with reference to the movable electrodes, substantially
as described.

page_text: 8) In an electrolytic meter, the employment of thermopiles for generating a
continuous from an alternating current, so as to measure an alternating current
by electrolysis substantially as described.
Dated this 20th day of August 1808
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.