Improvements in Electric Heaters.
Year: 1896

page_text: Improvements in Electric Heaters.
I, EDWARD ETHEL GOLD, of Number 64 West Seventy-seventh Street, in the
City of New York, United States of America, Manufacturer, do hereby declare the
nature of the said invention to be as follows:-
This invention relates to electric heaters, and aims to provide an improved and
simplified construction thereof applicable for use as heaters for electric cars, for
the state rooms of steam ships, and for other purposes.
In my heater the resistant medium consists of coils of wire which are extended
borizontally and arranged one above another, being confined in place between
upright insulating plates, the space between which is open at top and bottom, so
that a free upward circulation of air can take place between the plates and through
the open meshes of the successive coils.
The coils of wire are drawn open sufficiently to keep their convolutions out of
contact, and the upright insulating plates are formed with longitudinal horizontal
corrugations, grooves, or channels, in line with one another on their inner sides,
which constitute recesses between which the respective coils are received, and
whereby the coils are held in place. The plates may be made of any insulating
material of sufficient strength and which is unaffected by the heat, plates of asbestos
board moulded by pressure, coated or saturated with asbestos paint and then
tboroughly baked, having been found suitable. The plates are held together by
screws or bolts at intervals, and at the ends of the heater the plates are connected
together through upright blocks or cleats, to which they are fastened by screws or
otherwise. Through the respective cleats are passed bolts in line with the respective
coils to which the ends of the coils are connected, while on the outer side the
conducting wires are fastened to these bolts.
The electric heater thus made may be mounted or supported in any suitable way,
preferably by being enclosed in a casing of any suitable shape or construction.
The casing shown may be made of cast metal, or may be pressed or moulded, and
is dished sufficiently to provide an inner chamber or cavity sufficiently large to
receive the heater. The heater is mounted in this cavity in such manner preferably
as to keep it slightly out of contact with the casing. For attaching the heater to
the casing, screws may be passed through holes in the insulating plates and screwed
into bosses on the inner side of the casing, bushings being preferably interposed
between the screws and the plates. The heater is thus mounted within the casing
so that it can be transported therewith, and to mount it in place it is only necessary
to fasten the casing to the wall or other support by passing screws through holes
in the foot or base flange of the casing. To protect the wall from heat, it is
preferable to interpose a sheet of asbestos. The casing is formed with gratings or
perforated portions at top and bottom to admit of a free circulation of air, the air
entering at the lower grating, passing up through the heater, and out at the upper
grating.
For street car heating, I prefer to construct the heater with an elongated casing,
employing three coils one above another. For state rooms of ships and other
locations where a greater height is admissible, I may make the heater higher in
proportion to its width, employing for example six short coils in place of three
long ones. In either case the terminal wires may be carried out through holes in
the ends or sides of the casing in any convenient direction.

page_text: For regulating the amount of heat given out, I provide a suitable switch or
controller. With a three-coil heater, the switch may have a contact arm movable
to four different positions, and contact plates in positions 1, 2 and 3, position 4
being that in which the circuit is open or broken. In position number 1 the
switch connects coil number 1 alone in the circuit; in position number 2 it connects
coils numbers 2 and 3 in parallel; in position number 3 it connects all three coils
numbers 1, 2 and 3 in parallel; and in position number 4 it breaks the circuit
so as to throw the heater out of action. Various constructions of electric switches
are known by means of which these results may be attained, and my invention is
not limited to the use of any particular switch construction or arrangement.
An alternative arrangement is that in which the heating coils are connected
together serially, and the heat is controlled by a switch which acts to cut out one
or more coils, and thereby correspondingly reduce the resistance, so that a greater
volume of current passes through the remaining coils, and thereby heats them to a
higher temperature.
Dated this 4th day of April 1896.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.
Improvements in Electric Heaters.
J, EDWARD ETHEL GOLD, of Number 64 West Seventy-seventh Street, in
the City of New York, United States of America, Manufacturer, do hereby
declare the nature cf the said invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to electric heaters, and aims to provide an improved and
simplified construction thereof applicable for use as heaters for electric cars, for
the state rooms of steam ships, and for other purposes.
In my heater the resistant medium consists of coils of wire which are extended
horizontally and arranged one above another, being confined in place between
upright insulating plates, the space between which is open at top and bottom, so
that a free upward circulation of air can take place between the plates and through
the open meshes of the successive coils.
The coils of wire are drawn open sufficiently to keep their convolutions out of
contact, and the upright insulating plates are formed with longitudinal horizontal
corrugations, grooves, or channels, in line with one another on their inner sides,
which constitute recesses between which the respective coils are received, and
whereby the coils are held in place. The plates may be made of any insulating
material of sufficient strength and which is unaffected by the heat, plates of
asbestos board moulded by pressure, coated or saturated with asbestos paint and
then thoroughly baked, having been found suitable. The plates are held together
by screws er bolts at intervals, and at the ends of the heater the plates are
connected together through upright blocks or cleats, to which they are fastened by
screws or otherwise. Through the respective cleats are passed bolts in line with
the respective coils to which the ends of the coils are connected, while on the outer
side the conducting wires are fastened to these bolts.
The electric heater thus inade may be mounted or supported in any suitable way,
preferably by being enclosed in a casing of any suitable shape or construction.
The casing shown may be made of cast metal, or may be pressed or moulded,
and is dished sufficiently to provide an inner chamber or cavity sufficiently

page_text: large to receive the heater. The heater is mounted in this cavity in such
manner preferably as to keep it slightly out of contact with the casing. For
attaching the heater to the casing, screws may be passed through holes in
the insulating plates and screwed into bosses on the inner side of the casing,
bushings being preferably interposed between the screws and the plates. The
heater is thus mounted within the casing so that it can be transported therewith,
and to mount it in place it is only necessary to fasten the casing to the wall or
other support by passing screws through holes in the foot or base flange of the
casing. To protect the wall from heat, it is preferable to interpose a sheet of
asbestos. The casing is formed with gratings or perforated portions at top and
bottom to admit of a free circulation of air, the air entering at the lower grating,
passing up through the heater, and out at the upper grating.
Fig. 1 of the accompanying drawings is a front elevation of the heater casing;
Fig. 2 is a rear view of the heater in its casing, the heater being partly broken
away;
Fig. 3 is a transverse section of the heater and casing fastened against a wall;
Figs. 4 and 5 are transverse sections of the heater alone;
Fig. 6 is a horizontal section;
Fig. 7 is a diagram showing the circuit connections and controlling switch;
Fig. 8 is a rear view of an upright or six-coil heater;
Fig. 9 is a circuit diagram showing suitable switch connections for a six-coil
heater;
Fig. 10 is a diagram showing the connection of successive three-coil heaters with
one controlling switch.
In the drawings, B designates the heater proper, and A the casing. CC are the
coils or helices of resistant wire, and D D are the insulating plates connected
together by screws or bolts E E. The plates D D are preferably formed with
longitudinal grooves d d, whereby the coils are held in place. The screws or
bolts E E are passed through the spaces between the coils, and are preferably.
provided with insulating bushings e e, which may be of porcelain. The plates D D
may be of any insulating material, as moulded asbestos board, or porcelain, or of
metal suitably covered with insulating material. At their opposite ends the
plates D D are connected by means of upright cleats F, to which the plates are
fastened, and through which are passed bolts ff, to which the coils are connected
on the inner sides of the cleats, while on their outer sides the conducting wires are
fastened to these bolts, which thus constitute binding posts. Either the cleats F
are of insulating material, or the bolts require to be provided with insulating
bushings.
The henter B is mounted in the cavity of the casing A in any suitable way, as
by fastening screws G (Fig. 6) screwing through bushings g g into a base h
formed on the casing. The encased heater may then be fastened against a wall, as
shown in Fig. 3, a sheet of asbestos H being preferably interposed. The casing
is formed with gratings or perforations a a at top and bottom to admit of a free
circulation of air, the air passing up through the heater and out at the upper
grating, as shown in Fig. 3. A very effective means is thus provided for conducting
away the heat rapidly from the heater, thereby avoiding all overheating of the
parts thereof. The plates DD are kept cool by being exposed on both sides to
currents of air.
For heating electric street cars or tramcars, I prefer to construct the heater with
an elongated casing substantially of the proportions shown in Figs. 1 and 2,
employing coils of for example 14 inches diameter, and employing three coils one
above another as shown. Such heaters can readily be placed beneath the seats
without interfering with the existing construction of such cars, any suitable
number of heaters being placed end to end along each side of the car. For
state rooms of steam ships and other locations where a greater height is admissible,
I may proportion the heater as shown for example in Fig. 8, where it is made high
in proportion to its width, six short coils being employed in place of three long

page_text: ones. In either case the terminal wires of the coils which are lettered wow may be
carried out through holes in the ends or sides of the casing as shown, these holes
having suitable insulating bushings, or otherwise inay be carried out through the
bottom or top, or in any convenient direction.
If the plates DD are of suitably strong and properly finished material, no
extraneous casing is required. In Figs. 11 to 15 I have shown a construction in
which the plates D D are of metal, suitably enamelled or otherwise coated on at
least their inner surfaces to prevent electrical contact with the coils.
Fig. 11 is a front view of this construction of heater;
Figs. 12 and 13 are vertical transverse sections thereof;
Fig. 14 is a vertical longitudinal suction on the line 14-14 viewed from in
front;
Fig. 15 is a horizontal section on the line 15-15.
The plates DD are here made of enamelled sheet metal, the front plate being
bent back at top and bottom and flanged at & to meet the back plate, and the two
being fastened together by screws or rivets cc. The bolts E E by which the plates
are drawn together to clamp the coils, are provided with insulating bushings g or
they may be simply enamelled instead. In these figures the plates DD are not
grooved to form recesses for receiving the coils, but the coils are held by simple
frictional tangential contact with the plates. The surfaces of the plates where the
coils touch them are preferably roughened to prevent slipping of the coils, which
may be done by sprinkling sand or powdered glass on the enamelled or glazed
surface of the plates while moist and before baking the enamel. The omission of
grooves has a slight advantage, in that there is less surface contact between the
coils and plates, and the air space for upward circulation of air through the
meshes of the coils is of a width equal to the full diameter of the coils. The
open spaces at the ends of the plates are closed by plates or caps F F if desired.
The coils are connected at their opposite ends to binding posts and fl
respectively, which are fastened to or insulated from the back plate. The posts f
are shown in Fig. 15 as being extended back through the wall B', the electric
connection with the wire w being made by nuts ii behind this wall. The heater is
fastened to the wall by screws dd having interposed bushings to hold the heater
out from the wall and leave an air flue e between, an asbestos sheet H being
preferably placed against the wall.
For regulating the amount of heat given out by my heaters, a constant electro-
motive force being assumed, I may provide with a three-coil heater the switch
arrangement shown in Fig. 7. The coils CC are here numbered respectively
1, 2, 3, and their terminal wires w are connected to a switch J at one end, aud to
the out-going conductor e at the other, the incoming conductor & being connected
to the switch. The construction is such that in one position of the switch, coil
number 1 will alone be connected between the conductors be; in a second position
coils numbers 2 and 3 will be connected in parallel between the conductors bc; in
a third position of the switch all three coils 1, 2, 3 are connected in parallel between
the conductors; and in a fourth position of the switch the circuit is broken so as to
throw the heater out of action. Various constructions of electric switches are
known by means of which these results may be attained, and my invention is not
limited to the use of any particular switch construction or arrangement.
construction shown in Fig. 7, however, is in principle well adapted for this purpose.
It consists of a switch board having conducting contact plates, and a switch-
arm connected at its pivot to the wire b and arranged to sweep the contact
plates. In the first position it touches plate number which is connected with
coil number 1; in the second position it touches plate number 2 which is connected.
with coils numbers 2 and 3; in the third position it touches the twin plates, one of
which is connected to plate 1 and the other to plate 2, so that in this position the
current passes from the switch-arm through the conducting wires to all three of
the coils 1, 2 and 3; in the fourth position the switch-arm is out of contact with
all the contacting plates, thereby open-circuiting the heater.
The

page_text: 10 10 are
It is apparent that with this construction of switch only two wires
required to intervene between the three coils of the heater and the switch.
This is especially advantageous where several heaters are connected in succession
and all controlled by the same switch, this being the arrangement commonly
adopted in wiring heaters for electric tram-cars. This is indicated in Fig. 10,
where two heaters B B are thus connected with a single coutrolling switch J,
only two wires to w being carried from the switch to and between the respective
heaters. With the arrangements heretofore adopted, three wires would be required
for giving three different gradations of heat.
Fig. 9 shows another switch arrangement which is applicable with the arrange-
ment of heater shown in Fig. 8. The coils are here numbered from 1 to 6, and are
connected together serially by wires v. One terminal of coil number 1 is
connected to plate 1 of the switch J', while the opposite terminal of coil number 6
is connected to the outgoing conductor c. The incoming conductor b is connected
to the switch-arm i. Contact plate number 2 is connected between the coils 2 and 3;
contact plate number 3 is connected between coils 3 and 4. In the first position of
the switch the switch-arm rests on contact plate 1, so that the current flows through
all six coils in series and is opposed by their combined resistance, so that but a
comparatively feeble current passes, thereby generating but a low heat; in the
second position of the switch the arm i rests on contact 2, whereby coils numbers 1
and 2 are cut out and the current traverses the remaining coils in series, encountering
thus one-third less resistance than at first, thereby correspondingly increasing the
amperage and the amount of heat generated; in the third position of the switch
its arm rests on contact 3, so that the current passes through coils 4, 5 and 6,
encountering only half the resistance of the combined coils, and thereby still
further increasing the amperage and the amount of heat generated; in the fourth
position of the switch the coils are cut out. Numerous other arrangements of coils
in connection with a switch or switches may be made by means of which to control
the amount of heat generated by the heater.
My invention is subject to modification in details of construction without
departing from its essential features. When grooved plates are used it is preferable
to form the longitudinal grooves in the plates by corrugating the plates, thereby
retaining the plates of uniform thickness throughout, yet this is not essential, as the
grooves might be formed in other ways, as for example by means of pairs of
longitudinal ribs raised upon the plate, thereby forming the groove or channel
between them. The grooves or channels are preferably continuous as shown so as
to support the coil uninterruptedly from end to end, but this is not strictly essential,
as in some cases it may be found advantageous to interrupt the support afforded by
the grooves at intervals, the stiffness of the coil serving to sufficiently uphold it in
the intervals between the supports. Ordinarily the plates D D will be continuous
or imperforate as shown, but it may at times be found advantageous to perforate
the plates with either round or elongated perforations or otherwise, and either
contiguous to the coils or opposite the spaces between the coils.
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. The described electric heater characterized by a resistance coil or coils
confined between two parallel supporting plates, forming between them a space for
circulation of air through the meshes of the coils.
2. In such heater, the formation of the supporting plates with longitudinal
grooves for receiving and retaining the coils, substantially as and for the purposes
described.
3. The construction of such heaters with end pieces to which the plates are
fastened, and to which the ends of the coils are connected, substantially as and for
the purposes described.

page_text: 4. In such heaters, the provision of adjustable means by which the supporting
plates can be drawn together more or less tightly, and the intervening coils be
thereby more or less firmly embraced, substantially as described.
5. The combination with a heater of the character specified in Claim 1, of a
recessed casing partially enclosing it, and by which it is supported, as described.
6. An electric heater of the described construction, wherein the supporting
plates D D constitute the casing, and no extraneous casing is required.
7. An electric heater of the described construction, wherein the supporting
plates D D are of sheet metal coated with enamel or other insulating coating, and
exposed exteriorly to the air to permit free radiation of the heat conducted by the
metal plates from the coils.
8. An electric heater having three resistance coils in parallel, combined with a
switch and two intervening conducting wires, the one connected to one of the coils
and the other to the two remaining coils, and the switch constructed when in one
position to connect only with said first wire, in the second position to connect only
with said second wire, and in the third position to connect with both wires, to the
effect specified.
J. C. MEW BURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.