IMPROVEMENTS IN ELECTRICAL HEATING AND IN APPARATUS CONNECTED THEREWITH "
Year: 1883

page_text: LETTERS PATENT to John Scudamore Sellon of Hatton Garden in the County
of Middlesex, and Robert Percy Sellon of Surbiton in the County of Surrey,
Electrical Engineer for an Invention of "IMPROVEMENTS IN ELECTRICAL
HEATING AND IN APPARATUS CONNECTED THEREWITH
"
PROVISIONAL SPECIFICATION left by the said John Scudamore Sellon
and Robert Percy Sellon at the Office of the Commissioners of Patents on
the 16th April 1883.
JOHN SCUDAMORE SELLON of Hatton Garden in the County of Middlesex and
ROBERT PERCY SELLON of Surbiton in the County of Surrey Electrical Engineer
"IMPROVEMENTS IN ELECTRICAL HEATING AND IN APPARATUS CONNECTED
THERE WITH
"
This Invention relates to the application of Electrical Energy or currents in
whatsoever manner derived whether from a Dynamo or other machine direct or from
primary or secondary batteries or from any other source to heating or other
purposes where Electrical Energy is transformed into heat, and it further relates to
appliances or devices for automatically or otherwise regulating the supply of
Electrical Energy or current to be transformed into heat so that the temperature
may be regulated and maintained approximately constant at any degree desired
so long as the supply of Electrical Energy is available, the Invention also relates
to devices or arrangements for automatically or otherwise regulating and maintaining
such currents in Electrical heating apparatus so as to prevent an excess of Electrical
Energy or current from traversing the conducting or heating coils or portions of
the apparatus such as might cause waste of power and of heat or might tend to
oxidise or otherwise injure or destroy the apparatus.
In carrying out this Invention the coils or forms of iron platinum or other
metallic wire, sheet foil or other suitable form of metal or suitable material or
composition may be wound round or otherwise attached to or placed in proximity

page_text: to cylinders or blocks of any suitable fire resisting substance such as for instance
pumice stone asbestos fire brick or other substance or composition capable of
withstanding high temperatures which substances shall be at the same time of a
sufficiently insulating character and which may serve to absorb convey disperse or
retain heat without rapid or material deterioration or a composition may be
employed composed of a combination of metals or other substances capable of
transmitting current without offering undue resistance and which substances will
allow at the same time of being subjected to a high temperature without fusion or
material deterioration such composition to be wound round attached to or placed
in contact with or in proximity to some substance capable of resisting high
temperatures as mentioned above, this substance may then be placed in contact
with or in proximity to a metal or other vessel (which may be closed or open) in
which water or some liquid is contained or the vessel itself may be constructed of
earthenware fire brick, or some fire resisting substance and the coils or other form
of metal or suitable material may be placed in contact with or near the vessel or
in some cases the fire resisting substances themselves may be exposed to the direct
action of the air in order to avoid the loss in the transference of heat from the
above substance to a liquid and from the liquid to the matter to be heated.
In the application of heat to any ordinary purposes it may be desirable to raise
the temperature to a predetermined degree and then to maintain it at that degree
for any desired period which may be effected in many cases-by the expenditure
of less heat energy than was required to raise the temperature to that degree.
The second part of our Invention relates to means and devices for accomplishing
this end automatically-We sometimes employ a current of electricity traversing
the mercury or other liquid in a thermometer or any other apparatus affected by
variation in temperature such as a Pyrometer the said thermometer or other
instrument or appliance being affected by the temperature of the coils or substances
emitting heat or to be heated to control an electro magnet or magnets in a shunt
circuit with the heating coils, the object of this electro magnet or magnets is to
maintain a constant or approximately constant current in the heating coils and to.
prevent an excess of currents from injuring or destroying the coils or composition
or other matter by inserting a resistance into the circuits of the above coils or
composition or other matter whenever the current shall exceed its normal or the
.desired amount, this may be effected by causing an armature or core controlled by
the current in the shunt magnet to vary a resistance in the same circuit with the
coils or heating parts or other arrangements in such a manner that the current
passing in the coils or other arrangements may be regulated and an approximate
constancy be maintained controlling the temperature of the coils or other heating
arrangements. Or the thermometer or other instrument for the like purpose may
be dispensed with and the electro magnet or magnets be placed in the same circuit
with the heating coils or other arrangements maintaining a constant or approxi-
mately constant current in the heating coils in the same manner as before by
causing the core or armature controlled by the electro magnet or magnets to vary
a resistance which shall be in the same circuit with the heating coils or parts or
electro magnet or magnets may cause a portion of the current to be shunted from
the heating coils or parts instead of inserting a resistance in the same circuit with
them; in this way the desired temperature may be obtained without undue
deterioration or destruction of the heating coils parts or arrangements
•
It is obvious however that should the coils or heating parts continue to receive
their full share of current the temperature of the space or matter to be heated may
in time be raised beyond the temperature required In order to prevent this a
thermometer or other apparatus affected by temperature may be employed which
registers the temperature of the room or space or matter to be heated and which
may control an electro magnet or magnets in a shunt or high resistance circuit
with the main electro magnet or heating coils or other apparatus the circuit of this
electro magnets to be closed by the rise or fall of the mercury or other liquido

page_text: contained in the thermometer which thermometer is suitably constructed with
metallic contact for adjustments to any required degree of temperature. This may
either be done directly or by means of a relay or other device where a comparatively
weak current and electro magnet may close the circuit of the shunt magnet before
mentioned. This latter or other device by the attraction of an armature or core
controls an arm or lever or suitable arrangement which inserts a resistance in the
main circuit of the heating coils or parts causing a decreased current in the same
thus maintaining a more constant temperature in the space or matter to be heated or
the shunt magnet may break the current flowing in the heating coils or arrange-
ments until such time as the rise or fall of the mercury or other liquid shall break
the circuit of the shunt magnet and so increase or reestablish the current in the
heating coils or arrangements. Thus any desired temperature may be approximately
arrived at by adjustment of the contacts which can be made by the rise or fall of
the mercury or other liquid in the thermometer so that by such regulation with a
constant or variable current flowing in the main circuit any number of heating
coils arrangements or apparatus may be made to maintain approximately any
degree of temperature within reasonable limits and an approximate constancy of
temperature in each separate room space or matter to be heated according to
requirements.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Scudamore Sellon and Robert Percy Sellon in the Great
Seal Patent Office on the 16th October 1883.
JOHN SCUDAMORE SELLON of Hatton Garden in the County of Middlesex and
ROBERT PERCY SELLON of Surbiton in the County of Surrey Electrical Engineer
"IMPROVEMENTS IN ELECTRICAL HEATING AND IN APPARATUS CONNECTED
THEREWITH
"
This Invention relates to the application of Electrical energy or current in
whatsoever manner derived whether from a Dynamo or other machine direct or
from primary or secondary batteries or from any other source to heating or other
purposes where electrical energy is transformed into heat and consists in the
provision of appliances, or devices for automatically or otherwise regulating the
supply of electrical energy or current to be transformed into heat so that
the temperature may be regulated and maintained approximately constant at any
degree desired so long as the supply of electrical energy is available and to devices
or arrangements for automatically or otherwise regulating and maintaining such
current in electrical heating apparatus so as to prevent an excess of electrical
energy or current from traversing the conducting or heating coils or portions of the
apparatus such as might cause waste of power and of heat and might tend to
oxidize or otherwise injure or destroy the apparatus In the electrical heating
apparatus the coils or forms of iron platinum or other metallic wire, sheet foil, or
other suitable form of metal or suitable material or composition may be wound
round or otherwise attached to or placed in proximity to cylinders or blocks of any
suitable fire resisting substance such as for instance pumice stone asbestos fire
brick or other substance or composition capable of withstanding high temperatures
which substances shall be at the same time of a sufficiently insulating character
and which may serve to absorb convey disperse or retain heat without rapid or
material deterioration or a composition may be employed composed of a combination
of metals or other substances capable of transmitting current without offering
undue resistance which substances will allow at the same time of being subjected
to a high temperature without fusion or material deterioration such composition
to be wound round attached to or placed in contact with or in proximity to
some substance capable of resisting high temperatures as herein before mentioned
This substance may then be placed in contact with or in proximity to a metal or
other Vessel (which may be closed or open) in which water or some liquid or
Chemical Salt or compound may be contained or the vessel itself may be constructed
of earthenware firebrick or some fire resisting substance and the coils or other
form of metal or suitable material may be placed in contact with or near the vessel
or in some cases the fire resisting substances themselves may be exposed to the
direct action of the air in order to avoid the loss in the transference of heat from
the above substance to a liquid or chemical salt or compound and from such to the
matter or space to be heated.
In the application of heat to any ordinary purposes it may be desirable to raise
the temperature to a predetermined degree and then to maintain it at that degree
for any desired period which may be effected in many cases by the expenditure of
less heat energy than was required to raise the temperature to that degree We will
now proceed to describe the means by which we propose to carry our Invention
into effect.
We sometimes employ a current of electricity traversing the mercury or other
liquid in a thermometer (or any other instrument or apparatus affected by variation
in temperature such as a pyrometer) the said thermometer (or other like instrument

page_text: or apparatus) being affected by the temperature of the coils or substances emitting
heat or to be heated to control an electro magnet or magnets (or a solenoid or
solenoids) in a shunt circuit with the heating coils the object of this electro magnet
or solenoid (or magnets or solenoids) is to maintain a constant or approximately
constant current in the heating coils and to prevent an excess of current from
injuring or destroying the coils or composition or other matter by inserting a
resistance into the circuit of the above coils or composition or other matter whenever
the current shall exceed its normal or the desired amount. This may be effected
by causing an armature or core controlled by the current in the shunt magnet to
vary a resistance in the same circuit with the coils or heating parts or other
arrangements in such a manner that the current passing in the coils or other
arrangements may be regulated and an approximate constancy be maintained con-
trolling the temperature of the coils or other heating arrangements. Or the
thermometer or other instrument for the like purpose may be dispensed with and
the electro magnet or magnets be placed in the same circuit with the heating coils
or other arrangements maintaining a constant or approximately constant current
in the heating coils in the same manner as before by causing the core or armature
controlled by the solenoid electro magnet (or solenoids or magnets) to vary a
resistance which shall be in the same circuit with the heating coils or parts or the
electro magnet or magnets or solenoid or solenoids may cause a portion of the
current to be shunted from the heating coils or parts instead of inserting a
resistance in the same circuit with them; in this way the desired temperature may
be obtained without undue deterioration or destruction of the heating coils or
arrangements.
Should the coils or heating parts continue to receive their full share of current
the temperature of the space or matter to be heated may in time be raisea beyond
the temperature required In order to prevent this a thermometer or other
apparatus affected by temperature may be employed which registers the temperature
of the room or space or matter to be heated and which may control an electro
magnet or magnets in a shunt or high resistance circuit with the main electro
magnet or heating coils or other apparatus the circuit of this electro magnet or
magnets to be closed by the rise or fall of the mercury or other liquid contained
in the thermometer which thermometer is suitably constructed with metallic
contacts for adjustment to any required degree of temperature This may either
be done directly or by means of a relay or other device where a comparatively
weak current and electro magnet may close the circuit of the shunt magnet before
mentioned The device by the attraction of an armature or core controls an arm
or lever or suitable arrangement which inserts a resistance in the main circuit of
the heating coils or parts causing a decreased current in the same thus maintaining
a more constant temperature in the space or matter to be heated or the shunt
magnet may break the current towing in the heating coils or arrangements until
such time as the rise or fall of the mercury or other liquid shall break the circuit
of the shunt magnet and so increase or reestablish the current in the heating coils
or arrangements.
And in Order that our said Invention may be fully understood we shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheets of drawings the same letters of referenco
indicating corresponding parts in all the figures.
With reference to Figure I of the accompanying drawings, T may be a thermo-
meter or any suitable device affected by variation in temperature, the said
thermometer T being affected by the rise or fall in temperature of the coils C. C
wound round or suitably attached to the fire resisting block F; on the face of the
thermometer T are placed two metallic contact pieces M and M', the former of
which (M) is in permanent contact with the mercury in the base of the.
thermometer, the latter (M) being set at such a height upon the tube that when
the temperature of the coils has caused the mercury to rise. up to the point at
which it is required to shut the current off, the circuit of an electro magnet or-

page_text: solonoid S is closed through the mercury and contact pieces, the magnet S and
.thermometer T being either on a shunt with the coils CC or including some
source of power whereby the magnet S may become energised and by attracting an
armature may break the circuit of the coil C C in any suitable manner, for
instance as shewn in the figure by withdrawing a finger G from a cup H con-
taining mercury. Thus the circuit of the coils C. C remain broken until such time
as a drop in the mercury within the thermometer T causes a break in the circuit
of the magnet S when the circuit will be re-established in the coils C. C. Or the
thermometer T may be dispensed with as in Figure II. In this case the magnet
or solenoid S is placed in the same circuit with the heating coils CC. When an
excess of current tends to traverse the coils C. C. the core K shewn in the Figure
is sucked into the solenoid S and inserts in any suitable way a resistance in the
main circuit of the coils in such a manner as to permit of a diminished current to
traverse the coils and thus avoid destruction or rapid deterioration of the
apparatus; the resistance may be inserted as shewn in the Figure by the movement
of an arm connected to the core K over a series of contact pieces between each of
which a resistance R is inserted, or in some cases where it may not be desirable to
diminish the current flowing in the heating coils by inserting a resistance in the
main circuit, a device as shewn in Figure III of the accompanying drawings may
be employed where a portion or all of the current when it becomes excessive may
be shunted round a resistance; in this case the main current passes through the
magnet or solenoid S; when the current is at its normal the core K causes a
maximum of resistance to be inserted in the circuit R, which circuit is on a shunt
with the heating coils C C, or the core may cause this shunt circuit to be entirely
broken until such time as an excessive current passing in the solenoid S sucks in
the core K and by moving the contact arm N may cause such portion of the total
current to be shunted round the circuit R as to maintain a normal current in the
coils C C and thus prevent their destruction or rapid deterioration.
It is obvious however that should the coils or heating parts continue to receive
their full share of current the temperature of the space or matter to be heated may
in time be raised beyond the point required. Figure IV of the accompanying
drawings illustrates one method of obviating this. A thermometer T or suitable
apparatus affected by temperature is provided with two metallic contacts M M¹,
the former of which (M) is in contact with the mercury in the base of the
thermometer, the latter (M') being moveable along the face of the tube and
adjustable to any required degree of temperature. In connection with the above
metallic contacts is a magnet or solenoid S₁, the circuit of which is closed and
broken by the rise or fall of the liquid in the thermometer; or the rise or fall of
the liquid may be made to actuate a relay which may close the circuit of the
magnet S¹, the magnet being energized in any convenient way; on the mercury
rising to the degree required, videlicit: the degree at which the adjustable contact
has been set, the circuit of the magnet S' will be closed, which, magnet, by the
attraction of an armature or core K may be made to insert a resistance in the
circuit of the heating coils C C in such a manner that a diminished current will
flow through the coils and permit the temperature of the space or matter to be
heated to drop, when the circuit of the shunt magnet S¹ will be broken, and a
magnet S through which the main current passes will attract the core or armature K
and by diminishing the resistance in circuit with the coils will permit of an
increased current traversing them, which will raise the temperature again to its
normal or desired degree; or the aforesaid magnet S¹ instead of inserting a
resistance in the circuit of the coils CC may be made to break the above circuit
entirely.
By means of the herein before described arrangements according to our Invention
any desired temperature may be approximately arrived at by adjustment of the
contacts which can be made by the rise or fall of the mercury or other liquid in
the thermometer so that by such regulation with a constant or variable current
flowing in the main circuit any number of heating coils arrangements or apparatus

page_text: may be made to maintain approximately any degree of temperature within
reasonable limits and an approximate constancy of temperature in each separate
room space or matter to be heated according to requirements.
Having now described and particularly ascertained the nature of our said
Invention and the manner in which the same is or may be used or carried into
effect we would observe in conclusion that what we consider to be novel and original
and therefore claim as the Invention secured to us by the hereinbefore in part
recited Letters Patent is :-
In electrical heating apparatus, the provision of means for automatically cutting
out, or putting in, or diverting, the heating current, or part thereof, for regulating
the temperature of the beating apparatus, and for obtaining, and maintaining, an
approximately constant temperature, at the degree required, substantially as herein-
before described; also the various arrangements, or devices, for the said purposes
herein before described and illustrated in the accompanying Drawings.
In witness whereof we the said John Scudamore Sellon and Robert Percy
Sellon have to this our Specification sot our hands and seals this sixteenth day
of October One thousand eight hundred and eighty three