A METHOD OF AND APPARATUS FOR MEASURING AND REGISTERING ELECTRIC CURRENTS
Year: 1884

page_text: I, JOSEPH TAVENER, of Lawson Villa, Burgess Road, Basingstoke, in the county
of Hants, commercial traveller, do hereby declare the nature. of my invention
for A METHOD OF AND APPARATUS FOR MEASURING AND REGISTERING ELECTRIC
CURRENTS to be as follows:-
1st A tube terminating in bulbs, similar in principle to a differential ´air
thermometer, but having platinum wire or other substance, of sufficient resistance
to generate heat on the passage of a current of electricity through it, inserted
through each bulb; the whole being partly filled with a fluid, such as mercury, and
hermetically sealed.
2nd This tube with bulbs &c rests on a support, at a point intermediate between
the bulbs, and may be regarded as a hollow lever, whose support is its fulcrum, on
which it turns, and whose equilibrium can be disturbed by the displacement of the
contained fluid.
3rd The whole is so metalically connected up and arranged, that on inserting it
in a circuit, the electric current will first traverse one bulb, heating the resistance;
expanding the air, driving the fluid to the other bulb, making that heaviest,
turning the lever, breaking connection with the one bulb, making connection with
the other, heating the resistance contained in that, and in a similar manner again
turning the lever-this action continuing so long as the current passes, but its
frequency being dependent on the heat generated, which is equal to the product of
the electro-motive force into the quantity of current passing.
4th This lever with bulbs is also metalically connected with an electro-magnet,
in proximity to another lever, upon which the electro-magnet acts, in opposition to
a spring; and acted upon by this lever in proximity to the electro-magnet is a
train of wheels, whose spindles carry hands, movable over the faces of dials, on
which the registrations are to be made, so that at each turn of the lever with bulbs,
either connection is made or broken between it and the electro-magnet, causing
the lever in proximity to it to move through a limited distance, affecting the
train of wheels to the same extent, registering at each turn of the lever with
bulbs, the same quantity of heat generated by the passage of the current, or its
:

page_text: equivalent, the product of the electro-motive force into the quantity of current
passing in circuit.
5th Lastly I particularly point out that the essential feature of my invention is
the differential thermometer arrangement, or tube with bulbs, having a resistance
inserted through them, and so fixed and placed in a circuit, that the registration of
its movements, under the influence of the heat generated by the passage of a
current of electricity, shall also be a registration of the product of the current into
the electro-motive force.
I, JOSEPH TAVENER, of Lawson Villa, Burgess Road, Basingstoke, in the county
of Hants, commercial traveller do hereby declare the nature of my invention
for A METHOD OF AND APPARATUS FOR MEASURING AND REGISTERING ELECTRIC
CURRENTS and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :—
The tube terminating in bulbs A¹ A², similar in principle to a differential air
thermometer, and particularly referred to in my provisional specification, has,
preferably, platinum wire a¹ a³, a³ a^, &c, for the resistance, inserted through each
bulb A, A, and mercury W₁ W2, for the fluid, with which it is partly filled, the
remaining space containing air, and the whole hermetically sealed.
This tube with bulbs &c A¹ A2, is attached, at a point intermediate between the
bulbs A¹ A², to the middle of a spindle E, terminating in knife edges, which rest
on supports H, H, and this spindle E, passes through the centre of one or more
sets of four discs K1, K2, K³, K', or otherwised shaped pieces of metal, placed
side by side, and insulated from each other; the number of such sets of
discs K, K, K³, K, being regulated by the number of lights or quantity of
current the meter is designed to register.
The first and second disc K1, K2, of each set, are split through their diameter, in
a direction, at right angles with the tube with bulbs A¹ A, and the halves of each
insulated from each other. On the one side A2, of the tube with bulbs metallic
connection is made between the half of the first metal disc K¹, and one end of the
platinum wire a¹, in the bulb, the other end of the platinum wire a², being
connected with the half of the second metal disc K². On the other side of the
tube with bulbs, the other halves of the first and second disc are similarly
connected with the platinum wire in that bulb. Projections from the halves of the
first and second disc on one side H2, make contact, when that end of the tube with
bulbs is depressed, with mercury in the first and second compartments M¹, M³, of a
vessel placed beneath, and having a number of compartments, insulated from each
other, corresponding with the number of discs on the spindle E. Projections from
the halves of the first and second discs, on the other side A', similarly make
contact with the mercury in the first and second compartments K1, K2, when that

page_text: end of the tube with bulbs is depressed. A wire N¹, connects the first com.
partment M¹, containing the mercury, with the branch P¹, supplying the circuit,
and another wire N³, connects the second compartment M³, to the same branch-
the whole forming a shunt to such branch.
The third and fourth discs K³, K4, are connected at their upper part, and each
disc has a projection in a direction at right angles to the tube with bulbs A' A²,
which make contact, with the mercury in the third and fourth compartments M³ M*,
on the tube with bulbs getting in a parallel position, and these compartments are
similarly connected with the branch supplying the circuit forming a second shunt
to such branch, including in its circuit one of the electro-magnets B¹, actuating the
clock-work. The other sets of four discs K' K° K' K' is similarly connected with
the branch wire P³ & the other resistances in the bulbs as a³, a7 a³.
The clock-work consists of a train of wheels, whose spindles carry hands,
movable over the faces of dials, and is actuated from either the unit, ten, or
hundred, &c, spindle, by an electro-magnet B¹, &c, and lever C¹, &c working in
opposition to a spring D¹, &c placed in proximity to one or more of such spindles,
according to the number of lights or quantity of current the meter is designed to
register.
The supply of current to the bulbs of the movable arm A¹ A2, and its distri-
bution to either of the electro-magnets in proximity to the unit, ten, or hundred, &c
spindle is controlled by one, or more regulators R1, R2, R3, (provisionally protected
by me No 10699 & used in conjunction with this apparatus), according to the
number of lights or quantity of current the meter is designed to register, consisting
of a tube terminating in bulbs, substantially the same in principle as the one
movable on supports A¹ A², partly filled with mercury S¹ S³, and partly with air,
and hermetically sealed. A resistance is inserted through the bulb of R' & the
bulbs of R2, R3 and prolonged to the bottom of the mercury S¹ S³.
The current enters the regulator R¹, through the resistance T¹, to the mercury S¹, S³
As the current increases the temperature of that portion of the spiral in the
bulb (T), rises, heating and expanding the air in the bulb, displacing the
mercury S¹, S². So long as the current does not rise to a fixed quantity, as ten
amperes, it passes from the mercury S¹ S2, to the wire P¹, having a shunt to the
electro-magnet B', in proximity to the unit spindle-One portion of the current
circulating through the resistance a¹ a², in the bulb A2, at the depressed end,
heating and expanding the air in the bulb A³, driving the mercury W2, to the other
bulb A, making that heaviest, causing the arm or tube with bulbs A1 A2, to turn,
breaking connection with the one bulb A², and making connection with the
other A¹, heating the resistance as a¹, contained in that, and in a similar manner
again turning the arm: this action continuing so long as the current passes, but its
frequency depending on the current passing in the circuit on the arm getting in a
parallel position, while turning, contact is made between the third and fourth
discs K, K, and the mercury in the third and fourth compartments M³, M*,
beneath it, enabling a current to circulate through the coils of the electro-
magnet B', in proximity to the unit spindle, causing it to attract the lever C¹, in
proximity to it. On the arm with bulbs A¹ A falling, contact is broken between
the third and fourth discs K³ K, and the mercury, the electro-magnet B₁, ceases to
act, and the spring D', working in opposition exerts itself, moving the lever C¹
through a limited distance, affecting the train of wheels to the same extent,
registering at each turn of the arm with bulbs A¹ A³, a unit of heat, which may
represent an ampere or Volt-ampere.
On the current rising to the fixed quantity, or ten amperes, sufficient heat is
generated in the bulb of the regulator R¹, to so displace the mercury S¹, S' as to
break connection with the wire P¹, having a branch to the electro-magnet B₁, in
proximity to the unit spindle, and make connection with the wire P*, in the other
limb, having a branch to the electro-magnet B³, in proximity to the ten spindle and
second set of discs, shewn in drawing. A resistance inserted in this branch to the
bulbs A A², reduces the current one-tenth, but the registrations are now made in

page_text: tens, instead of units, and this principle of registration is capable of extension to
hundreds, thousands, &c, by the addition of other regulators, suitably connected,
without any further increase of waste of current than when units are being
registered. The heat generated in the resistances V1 V₁ displaces the mercury &
introduces an increasing resistance into the branch to the bulbs of the movable
arm & a decreasing one to the lamp thereby controlling the current & making
the heat generated in the bulbs of the movable arm proportionate to the current.
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
1st The tube terminating in bulbs A' A2, similar in principle to a differential air
thermometer, partly filled with mercury W₁ W2, and partly with air, having
resistances a¹ a², as a³, &c, inserted through the bulbs A1, A2, and the whole
hermetically sealed, and connected with the other parts and the circuit, as
specifically set forth; so that the registrations of its movements, through the
displacement of the mercury WW2, by the heat generated in the bulbs A1, A2, on
the
passage of a current of electricity, shall also be a registration of the current
passing in the circuit.
2nd That part of the registering apparatus, which drives the train of wheels or
clock-work, consisting of one, or more than one, electro-magnet B¹, &c, and
lever C, &c, working in opposition to a spring D1, &c; 80 placed in proximity to
one or more of the spindles carrying the unit, ten, or hundred, &c hand that the
train of wheels can be driven, by the attraction between the electro magnet, and
the lever, from any one of such spindles, through the intervention of suitable
toothed wheels; thereby enabling units, tens, hundreds, &c, to be registered, at
each turn of the arm with bulbs, according to the quantity of current passing in
the circuit.
Date: 20th low of Sentember 1884