Improvements in and relating to Electric Heaters.
Year: 1897

page_text: Date of Application, 16th Dec., 1897-Accepted, 29th Jan., 1898
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Heaters.
I, EDWIN FORSYTHE PORTER, a citizen of the United States of America, residing
at 109, Bower Street, in the Town of Roxbury, County of Suffolk and State of
Massachusetts, United States of America, Gentleman, do hereby declare the nature
of this invention, and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
This invention relates to that type of electric heating, apparatus disclosed and
broadly claimed in British Patent to Mark W. Dewey, No. 5595, dated March 31st,
1891, and consists in certain improvements thereon' hereinafter described.
Such heaters to be adapted for commercial use under the varying conditions, to
which they are subjected must be strong and durable, compact and neat in con-
struction, and a large amount of wire must be arranged in a comparatively small
space, further, said wire must be held firmly against the action of centrifugal
force and must also be carefully and properly insulated and confined to the limits
of a flat blade, that is to say, it should not protrude beyond the surface acting on
the air and should not be liable to be broken or otherwise disarranged or electrically
disturbed.
$141
After a thorough investigation and many experiments I have 's discovered that
the wire which constitutes the electrical heating conductors when embedded in an
air resisting medium, such as enamel, accomplishes and meets all the requirements
necessary for the construction of 'a 'commercial electric heater. In a heater so con-
structed with the electric heating conductors embedded in enamel the wire is pro-
tected from the action of the air and oxidation is prevented, it is held firmly in
place against the action of centrifugal force, and the different convolutions of the
wire are held separately one from the other,, preventing, short-circuiting: The
wire is protected from contact with other bodies, and the surface of the fan blade is
smooth and even and not broken up by the protruding of the wire, so that no con-
flicting currents of air are produced and the fan is capable of doing its best work
as a blower and agitator; and furthermore, it makes a neat," compact and light
structure.
The enamel is tenacious, adhering firmly to the blade, and therefore not dis-
turbed by the rotation of the fan, it has sufficient mechanical strength to resist
any strain to which it may be subjected in this construction. It is a perfect in-
sulator and therefore prevents short-circuiting and also excludes the air from
contact with the heating conductor and thereby prevents oxidation and is non-
soluble, and therefore not affected by moisture, and in fact, meets every require-
ment of an electric heater of the type herein described.
In the accompanying drawings:
Figure 1 represents a side view of a ventilating fan and electrical heater mounted
thereon suspended from the ceiling.
Figure 2 is a detail view of one of the blades showing the wires embedded in
the enamel or glaze.
Figure 3 is an enlarged view of the thermostat in the electric circuit.

page_text: Like letters of reference refer to like parts throughout the several views.
Fixed to the ceiling B is a frame A which, supports a shaft from which the
blades D are extended, and a suitable electric motor rotates said shaft and blades.
Fare electrical conductors extending from any source of electricity to the
terminals G G¹ of the motor E, and G2 is an electrical resistance in the conductor F
for controlling the current. H H are conductors on the branch circuit connecting
the conductors F F to the terminals J and J, and G³ is an adjustable resistance
circuit maker and breaker in the conductor H¹ for controlling the current flowing
to the heater K mounted upon the blades of the fan. Instead of connecting the
conductor H to the conductor F between the terminal G' and the adjustable resist-
ance G2 said conductor may be connected as shown by the dotted line G+.
The heater K is of wire of suitable metal serpentinely arranged, and after the
first coating of enamel or glaze or other: substance having similar properties is
applied to the blade of the fan, said wire is laid on said coat and another coating
of enamel is applied on top of the wire and the two coats adhere together with the
wire in the center of the enamel, so that the wire is insulated from the blade of
copper or other metal and is also protected from the air to prevent oxidation and
held firmly in place, and the blade presents a smooth surface to the air so that the
air may be blown in the desired direction instead of being cut up by the projec-
tion of the resistances from the blades.
In order to convey the electricity from the stationary terminals J J₁ to the
rotating heating blades of the fan, I fix two insulated metallic rings L L' upon
the shaft C between said terminals so that they will revolve with the shaft, and
extend metallic fingers or brushes M M from said terminals to the rings to bear
with their free ends on the periphery thereof with the brush M bearing upon the
ring L and the brush M bearing upon the ring L¹. From these rings electric con-
ductors N N¹ extend to the wires of the heater K embedded in the enamel O. If
heat is not desired the circuit to the heater K may be opened by nieans of the cir-
cuit breaker G³, and the fan may be rotated without supplying heat. In this
blade (Figure 2) the heat is imparted to the air from the enamel which receives
its heat from the resistance wire by direct conduction.
In this construction the object is primarily to heat and circulate a body of air
rapidly by bringing a greater volume in contact with the heated surface than is
the case with the ordinary radiator, by means of power through the agency of the
revolution of the blades.
As shown in Figure 3, which illustrates an enlarged detail view of the thermo-
stat P, the electrical conductor F is connected with the thermostatic strip 2 at
the point p¹, the current flowing through said strip 72 through the link con-
nected at p to said strip, and this link is secured to the switch Q at the point p³.
A hand p is arranged with a graduated scale for the purpose of regulating the
temperature. The thermostatic strip 72 is operated by the temperature of the air,
being lengthened and shortened, thereby making and breaking the circuit through
the switch Q. The hand 7 is set at a desired degree, the rising of the temperature
beyond this point opens the switch and cuts off the heat, and the lowering of the
temperature again closes the switch.
While I have shown the invention embodied in a revolving fan, yet it may be
carried out equally as well with a fan having a reciprocating or other movement.
I do not limit myself to the arrangement and construction shown, as the same
may be varied without departing from the spirit of my invention.
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 combination with a fan, and a motor to, operate the same, of an electri-
cally heated conductor mounted upon said fan and embedded within an air
resisting medium.
2. The combination with a fan, and a motor to operate the same;, of an elec-

page_text: trically heated conductor mounted upon the blades of said fan and embedded within
an air resisting medium.
3. In an electric heating apparatus, one or more heat-developing electrical con-
ductors embedded within an air resisting medium, and a motor for moving said
conductors.
4. In an electric heating apparatus, one or more heat-developing electrical con-
ductors embedded within an air resisting medium, a fan, and a motor for moving
said fan.
5. The combination with a fan and a motor to operate the same, of an electrically
heated conductor mounted upon said fan and embedded within enamel.
6. The combination with a revolving fan, and a motor to operate the same; of
an electrically heated conductor mounted upon the blades thereof and embedded
within enamel.
.
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1007
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.