Improvements in Electric Heaters, especially for Cars.
Year: 1894

page_text: Date of Application, 18th Dec., 1894-Accepted, 9th Feb., 1895
Improvements in Electric Heaters, especially for Cars.
I, GEORGE HERBert Whittingham, of No. 703 Equitable Building, in the
City of Baltimore, State of Maryland, United States of America, Electrical
Engineer, 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:-
This invention relates to an improvement in electric heaters for cars and provides
for a pipe-constructed electric heater. One object of my improvement in electric
heaters is to construct an apparatus with a view to distributing the heat in the car
to the best advantage, and to accomplish this in such manner that the resistance
wire generating the heat shall not be overtaxed.
The invention is illustrated in the accompanying drawing, in which,
Figure 1 is a perspective view of a car with one side broken away to expose the
interior and show the improved electric heater.
Figure 2 shows the adjoining or abutting ends of two tubular heaters, electrically
connected, being a side view of one heater and a sectional view of the other.
Figure 3 is a cross-section of a tubular heater, taken on the line of the binding
post.
Figures 4, 5, and 6, are detail views of the means for mounting the tubular
heaters in the car.
Figure 7 shows the adjoining ends of parallel pipes connected by a conductor
wire.
Figure 8 shows one end of a tubular heater in section, being a modification of
the internal construction shown in Figure 1.
Figures 9 and 10 are diagrams showing the circuit of my heater as arranged in
a car and showing how the heat can be turned on at one side only or at both sides.
I employ pipes or tubes, D, of small diameter and of iron or like material
suitable for rapidly radiating heat. These pipes contain a resistance wire, A,
which has its ends connected with binding posts, B, which extend crosswise
diametrically through the pipe or tube. The binding posts, B, have at each end
a head, a, and at the other end a screw-thread, b; two insulating collars or
bushings, e, surround each binding post and insulate the post from the pipe, and
nuts, 6, on the screw-threaded end serve to confine the bolt and also retain the end
of a conducting wire, C. Each end of the pipe is closed by a screw-cap, d, which
is independent of the binding post and may be put on or taken off without disturbing
the binding post, the resistance wire, or the conducting wire.
Suitable electric insulation is placed in the radiating pipe and interposed between
the resistance wire, A, and the inner surface of said pipe; the insulating material, h,
employed, which may be clear loose sand, pulverized quartz, or some other highly
efficient conductor of heat, is filled in between the resistance wire, A, and the inner
surface of the radiating pipe. The pipe containing the resistance wire, A, has an
outer exterior surface only for radiating heat.
As a precaution to prevent the possibility of contact between the resistance
wire, A, and radiating pipe, D, an insulating tube, E, of glass or mica, is employed
in the said pipe. This glass or mica tube, E, in the present instance, surrounds
the resistance wire and extends lengthwise of the pipe, D. The heat-conducting
medium or packing, h, completely fills the radiating tube, D, and surrounds the

page_text: resistance wire, A, and is on both sides of the glass or mica tube, E, and is packed
tightly so as the better to serve as a heat-conductor from said wire, A, to the
pipe, D. Instead of the glass or mica tube the inner surface of the radiating
pipe, D, may be coated with an insulating enamel, E', as represented in Figure 8.
By this construction the heat of the wire, A, is rapidly conducted to the wall of
the radiating pipe, D, and therefrom readily delivered to the atmosphere.
The radiating pipes may be of any desired length. When the radiating
pipes, D, are complete, with resistance wire, binding posts, the insulating, heat-
conducting filling, and end-caps, they are most perfectly adapted for use in street
cars where they may be mounted so as to distribute their heat in the car, in the
most effective manner.
Figure 1 shows the manner of placing the radiating pipes or heaters on the
risers or supports, 1, of the car-seats, J.
To extend a series of these radiating pipes, D, along the entire length of the
seat-riser, I, of any ordinary street car, two or three sections of radiating pipes
are preferably used. The pipes are supported by pillow-blocks, K, having
notches, l, to receive the pipes which are placed parallel two, three or more in a
section; these blocks are made fast to the risers, I. The pipes are held in the
notches by confining blocks, m, which are placed as a bridge across or between two
adjoining parallel pipes so that one end of said block, m, will bear on one pipe and
the other end of the block ou the next adjoining pipe; a screw, n, is entered
through each block and between the said two pipes into the pillow-block, K, and
thus confines the pipes. If the two parallel pipes are not perfectly true in place in
the notches, or if any other variation or irregularity exists, the confining blocks, m,
will tilt from one pipe to another to accommodate such irregularity and thus the
pipes will be held tight and will not be rattled by the jar motion of the car. A
suitable plate or frame, O, covers the confining blocks, the pipe-ends, and the
pillow-blocks.
The electric wire, U, is connected with a binding post, B, on the end of one
pipe, D; the other end of said pipe and the end of another pipe abutting said
pipe, as in Figure 2, have their binding posts connected by a wire, (", as shown
in Figure 7. This manner of connecting the resistance wires of the radiating
pipe can go on indefinitely, thus enabling the radiating pipes to be placed or
arranged in a car to the best advantage.
It will be seen that this radiating-pipe form of electric-heater affords, relatively
to the enclosed resistance wire, a large heat-radiating surface, and therefore such
heater will deliver from a given resistance wire the greatest number of heat units
with such rapidity as to prevent the temperature of the wire from rising many
degrees above the actual temperature of the pipe. It is evident that the resistance
wires of this heater may be operated by an electric current which will maintain
the wires at such a comparatively low temperature as to avoid injury to the
resistance wire.
In the diagrammatic views, Figures 9 and 10, the heater circuits are shown in
such manner that the electric current from the trolley may be conducted to the
heaters at one side of the car only or to the heaters at both sides. In Figure 9
the circuit shown is continuous from one side to the other of the car, with one end
only of the circuit in connection with the ground; a switch, p, is provided at a
point between the trolley and the heaters to regulate the supply of electric current
to the heaters.
In Figure 10 there are two independent circuits instead of one,-a circuit at
each side of the car. Each of these circuits has a connection at one end with the
trolley and a switch, one designated, and the other r¹, between the trolley and
the heaters whereby the electric current may be supplied to either one of the
circuits while the current is shut off from the other circuit, or both circuits may be
supplied with the electric current. In this instance both circuits have a common
connection, ats, with the ground.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is,
1. In an electric heater, the combination of a casing having an outer exterior
surface only for radiating beat; a resistance wire within the casing; and an
electric insulating, heat-conducting filler packed within the casing and separating
the resistance-wire from the casing.
2. In an electric heater, the combination of a pipe casing having an outer
exterior surface only for radiating heat; a resistance wire within the pipe; an
electric insulating, heat-conducting filler packed within the pipe and separating the
resistance wire from the pipe; and a cap closing each end of said pipe.
3. In a system for heating cars by electricity, the combination of a radiating
pipe or a series of pipes mounted within the car; an electrical resistance wire
within said pipe or pipes; and a packing filling the pipe or pipes for insulating the
said resistance wire from the wall of the pipe and which also serves to conduct the
heat of the resistance wire to the pipe.
4. An electric heater comprising a pipe having an outer exterior surface only
for radiating heat; a resistance wire within the pipe; means in the pipe for
sustaining the resistance wire; a heat-conducting medium completely surrounding
the resistance wire and filling the pipe; a binding post projecting from the sides
of the pipe and connected with the resistance wire; and a cap closing each end of
the pipe and independent of the binding post.
5. An electric heater comprising a pipe having an outer exterior surface only
for radiating heat; a resistance wire within the pipe; a heat-conducting medium
completely surrounding the resistance wire and filling the said pipe; an electric
insulator additional to the said heat-conducting medium and separating the
resistance wire from the pipe; and a cap closing each end of said pipe.
6. An electric heater comprising a pipe having an outer exterior surface only
for radiating heat; a resistance wire within the pipe; a glass or mica tube
surrounding the resistance wire; a heat-conducting packing surrounding the said
wire and filling the radiating pipe; and binding posts extending crosswise through
the pipe at the ends of the glass tube.
7. In an electric car-heater, the combination of the pillow-blocks having notches
For the pipes; radiating pipes containing resistance wires and placed in said
notches; wires connecting the resistance wires of said pipes; and blocks, m,
placed as a bridge across two adjoining pipes with one end of said block bearing
on one pipe and the other end on the other pipe; and a screw, n, entered through
each block and between the two pipes into the pillow-block.
Dated this 13th day of November 1894.
GEORGE HERBERT WHITTINGHAM.