Improvements in Electric Heating Apparatus.
Year: 1890

page_text: Date of Application, 23rd Sept., 1890-Accepted, 20th Dec., 1890
COMPLETE SPECIFICATION.
[Communicated from abroad by ERNEST ABSHAGEN, of 632, West Taylor Street,
Chicago, Illinois, United States of America, Mechanical Engineer.]
Improvements in Electric Heating Apparatus.
I, WILLIAM ROBERT LAKE of the firm of Haseltine, Lake & Co., Patent
Agents, 45, Southampton Buildings, in the County of Middlesex, 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 improvements in electric heaters in which one or a series
of resistances are placed in the circuit of an electric current operated in conjunction
with a surrounding non-conductive heat retaining material, and the object of my
improvement is, First to provide the resistance with a non-conductive material of a
fluid and oily substance, such as sperm oil, cotton seed oil, lard oil, etc., or any other
fatty oil of a non-volatile character, which fluid material, unlike others heretofore
employed for this purpose, will always be in close contact with the resistance piece
either when hot or cold, and not shrink away by expansion or contraction as is the
case in other apparatus for like purpose, where earthy or mineral non-conductors,
like powdered clay, soapstone, plaster of Paris, etc., is employed. Second, to afford
facilities for taking up and retaining the heat generated by the resistance piece in
large quantities and at a high temperature. In order to remove the internal
pressure to which the casing of my electrical heating apparatus is subjected by
means of the expansion of the oil when heated, no precaution against internal
pressure other than that caused by the expansion of the oil is needed to be guarded
against. Third, to regulate the amount of heat required for each heater by shunting
automatically the current which supplies the electric energy by means of an
arrangement in the form of a governor set in operation by the heat developed in the
oil and acting through the expansive force of this fluid against an expansion
governor, which latter stands in connection with a shunt or rheostat of any approved
form, whereby the amount of current supplied to the resistance piece will be
automatically regulated, and the heat radiating from such electric heater will be
maintained at an even temperature.
I attain these objects by the mechanism illustrated in the accompanying drawing,
in which similar letters of reference indicate like parts, and in which
Fig. 1 is a longitudinal vertical view of my electric heater, in the shape of a
radiator;
Fig. 2 is a cross sectional view of the same;
Fig. 3 shows my appliance attached to a cooking stove, and
Fig. 4 illustrates my electric heater as used in connection with a steam boiler.
The casing A which forms the radiator proper is screwed to its base B. As is
usual with radiators the upper part A is subdivided into a number of compart-
ments a, a, a, for the purpose of giving as much radiating surface as possible. All
these compartments a, a, a are in communication with the lower compartment a' in
the base B, and are filled entirely with whale oil, or other oily fluids. The electrio
wire coming from the electric generator G, of any known form, is introduced at d
into the lower compartment a of the base B and suspended within said compart-
ment a' and connected therewith is the resistance coil R while the return wire 2
will leave the base B preferably at or near the same place d where wire 1 enters, and
by returning to the generator & complete the circuit.
It will be readily seen that in case the resistance coil R is of proper size to the
line wire 1 and to the electric current supplied by the latter, that according to the

page_text: well known "Joule's law of resistance a proportionate amount of heat will be
generated in the resistance coil R, which being surrounded by oil will be prevented
from fusing and will transfer such heat to the body of oil within the heater. The
heat will gradually rise into the upper compartments a a and be rapidly heated
throughout the radiator, which latter in the usual manner will radiate such heat in
proportion to its heating surface. The ratio of expansion of oil being well known I
have made provision for giving to the radiator an additional space into which the
enlarged bulk of the heated and expanded oil may flow, without subjecting the walls
of the radiator to any inward pressure. For this purpose I establish communication
between all of the upper compartments a a, as shown at a², and by providing an
expansion governor E at or near this point, the oil, even if unequally expanded in
any of the intermediate compartments a a of the lower and upper space a¹ a², may
have free access to said governor E. The governor consists of a piston e which fits
snugly into the piston cylinder f, which latter forms part of the upper compart-
ment a². It will readily be seen that the expansive force of the oil will gradually
push the piston e outwardly and thereby offer more space for the enlarged bulk of
the oil when heated, while at the same time in the cooling of the oil the outer
atmospheric pressure will push the piston again inwardly toward the stop g and
thereby prevent the formation of any air space in the radiator, my object being to
have the oil in contact with all parts of the radiator casing and to prevent the
formation of steam and vapour in such air spaces. At h is shown an overflow pipe C
heretofore mentioned, which latter has communication with the outer air by means
of the air vent k. Should, by reason of unforeseen causes, by too rapid heating of
the oil or failure of shunting off the current, as will be described hereafter, the
internal pressure becomes too great, then the piston E will pass the overflow h and
a sufficient amount of oil will flow off into the pipe C and relieve the internal
pressure.
In order to regulate the heat supplied by means of the resistance coil R to the
surrounding oil, I have provided the piston E at p with an insulated contact point
and I carry a wire 3 of low resistance to the electric generator G, while another
adjustable contact point q enters the head o properly insulated and connected by
wire 4 to the generator G. If now the heat supplied to the resistance coil R has
expanded the oil within the radiator sufficiently far and where it is deemed advis-
able to shut off any further supply of electric energy to the wires 1 and 2, then the
piston E carrying the contact point p has advanced far enough by means of the
propelling force exerted against it from the expanded oil to come in close contact
with the contact point q and will thereby short circuit the current and relieve the
resistance coil R of any further action. The oil being heated now to such an extent
as I deem it necessary will radiate through its casing for a long time without
receiving a fresh reheating, but as soon as sufficiently cooled off its bulk will try to
contract to its former capacity. As soon as this takes place the outer atmospheric
pressure will force the piston E inwardly and thereby break contact between p
and q and close the current 1 R 2 G and supply a fresh electric current to the
resistance piece R. By this means it is possible to maintain the same temperature
within the radiator.
In order to regulate the amount of heat which it is desirable to reach by the
radiator I have shown, in Figure 1 an adjusting screw J, which passing through to
the cylinder head o will permit the insulated contact point q to be brought nearer
toward the contact point p, and lessen the distance to be travelled by the cylinder
piston E, which conversely will not permit the temperature of the oil to rise to its
full extent, by short circuiting the current supplied to the resistance R at a time
when the oil has received a less quantity of heat from R, and thereby has not
expanded to the maximum point to which this radiator has been set or tested. Any
well known device of short circuiting the current or diminishing the strength of the
same gradually, as by means of a rheostat or rheocord may be employed in
conjunction with the forward and backward motion of my expansion governor.

page_text: One or a number of such heaters may be placed in connection with a main line,
receiving electrical energy from the same source or generator, and these electrical
heaters may be wired either in series or in multiple are.
Fig. 3 shows my invention as adapted for a cooking range, with hot water
apparatus, in which A is the surrounding casing, X the oil surrounding the different
compartments where heat is needed for cooking purposes, such as at a for boiling,
at y for roasting or baking, at for cake frying. w is a non-heat conducting
insulator as mineral wool, asbestos etc., placed at such parts where it is desirable
not to radiate outwardly but to concentrate the heat inwardly. E is the expansion
governor and R the resistance piece.
Fig. 4 shows my invention as adapted for raising steam in boilers without the use
of a furnace or grate fire. The tubes a a are connected at either end of the boiler
with a head compartment a' a2 filled with oil X. Through one or a number of tubes
is strung the resistance piece R and imparts the heat embodied in the oil to the
surrounding water of the boiler. As oil is a good electrical non-conductor the
current supplied to the different forms of my electrical heaters will not be grounded
or give any electrical shock to the touch of the metal casing.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, as communicated to me by my
foreign correspondent I declare that what I claim is :
1st. In an electric heat generator a resistance piece covered with a non-conductive
fluid, such as oil, lard or its equivalent, substantially as specified.
2nd. In an electric heat generator a resistance piece covered with oil and
combined with heat reservoirs, substantially as specified.
3rd. In an electric heater a closed vessel within which a resistance piece is
sustained covered with an oily fluid, said resistance piece being in circuit with a
generator of electricity, substantially as specified.
4th. In an electric heater a resistance piece being in continuous contact with an
oily fluid, substantially as specified.
5th. The combination in an electric heater of a metallic box or case with a heat
retaining material in the form of an oily fluid in said box or case and an electrical
resistance piece covered by said oily fluid, the resistance piece being placed in
circuit with a generator of electricity and an expansion governor arranged to
operate in such manner so as to remove automatically all external pressure from the
heater caused by the expansion of the heated oil within said heater, as herein set
forth and described.
6th. In an electrical heater a casing containing an oily fluid and surrounding an
electrical resistance piece which latter is in circuit with an electrical generator, an
automatic expansion governor operated by the expansion and contraction of the hot
and cold oil within said heater and an electrical shunt operated by the expansion
governor and so arranged as to withdraw at any certain point the electrical current
from the resistance piece within said heater by short circuiting the current auto-
matically at certain stages of the temperature of the oil within the heater, as herein
set forth and described.
7th. In an electrical heater the casing A, containing the oily fluid X, the
resistance piece R, placed within the current of the generator of electricity which
resistance piece is surrounded by said oily fluid X, the expansion governor E
actuated upon by the force exerted by the expansion of the heated oily fluid X and
pressing the same outwardly and thereby preventing an external pressure against
the inner sides of the heater, in combination with an adjustable shunt p q so arranged
that as soon as the limit of the desired expansion of the oil and the corresponding
temperature of the same has been reached, the energizing current supplied to the
resistance piece R will be automatically shunted off and any further supply of heat
to the radiator withdrawn, and reinstated again in the resistance piece automatically
as soon as the oil commences to contract by breaking the shunt circuit and closing
the resistance circuit, as herein set forth and described.

page_text: 8th. In an electrical heater a case A containing the oily fluid X, one or a series
of resistances R which latter are in circuit with an electric generator in combination
with an expansion governor operated by the action of the expanded oily fluid when
heated, and an overflow pipe or reservoir d connected with the main oil reservoir by
means of an overflow passage h which is automatically opened by said expansion
governor for the purpose of relieving the main reservoir of a part of its bulk to
prevent any internal pressure caused by the expansion of the heated oil within the
heater, as and for the purpose herein described.
9th. In an electrical heater arranged in the form of a cooking range a closed
metal casing containing an oily fluid which is brought to a high state of temperature
by means of an electrical resistance piece placed within the oil, said resistance piece
being energized by a generator of electricity, and said metal casing arranged in such
a manner that the same is subdivided in a partly closed, partly open receptacle,
which may be readily reached from the outside and used for the reception of various
articles such as food, in order to subject them to the influence of the heat radiating
from such metal casing, in combination with an expansion governor which controls
the internal pressure exerted by the heated oil, as and for the purpose set forth.
10th. In an electrical heater arranged in the form of a steam boiler for the
generation of hot water and steam, a metal casing composed of a series of tubes
traversing the boiler and surrounded by the water which is to be raised to and
beyond its boiling point, the interior of said tube being in communication with each
other by connecting heads, placed on either end of the tubes which form in
connection with the latter one closed vessel, such vessel being filled with an oily
fluid and brought to a high state of temperature by means of one or a series of
resistance pieces traversing this closed vessel, and energized by an electric current
which heats the surrounding oil in combination with an expansion governor for the
purpose of removing any internal pressure caused by the expansion of the oil when
heated, as herein described.
1
1
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.