Improvements in Electrical Heaters.
Year: 1893

page_text: Date of Application, 13th June, 1893-Accepted, 22nd July, 1893
COMPLETE SPECIFICATION.
Improvements in Electrical Heaters.
I, JAMES FINNEY MCELROY of No. 936 Broadway City and County of Albany,
State of New York, United States of America, Manufacturer, 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 mechanism for converting the energy of an electric
current into heat energy for the purpose of warming an apartment; and the object
of my invention is to provide a device for heating street cars, railway trains or
houses by electricity.
I accomplish this object by means of the mechanism illustrated in the accompanying
drawings, in which
Fig. 1 is an elevation of a cabinet containing my heater.
Fig. 2 is a section along the lines 1-1 on Fig. 1.
Fig. 3 is a detail view showing a substance placed between the adjacent layers
of the wire, and
Fig. 4 is a section along the lines 21-2¹ on Fig. 2.
Similar letters refer to similar parts throughout the several views.
Around the spindle B, I place an insulating substance C which may be porcelain,
or it may be of asbestos, or other suitable heat resisting insulating substance.
Around the insulating substance on the spindle B. I wind in a spiral path the
wire D in a continuous spiral form, in such a manner that the wire touches the
insulating substance only at one edge of each spiral. These spirals are formed
and wound after the manner of a spiral spring, and the coil of the spirally wound
wire is passed about the insulating material on the spindle B beginning at one end
of the spindle and continuing along the spindle toward its opposite end, each layer
of the coil being separated from the adjoining layer by the insulating material
surrounding the spindle, so as to prevent electrical contact. I also place between
the adjacent layers wicking N or similar substance, as shown in Fig. 3, when I use
my heater in direct contact with the atmosphere.
In this way, the spirally.formed coil, of wire is drawn out and wound about the
insulating substance on the spindle in such a manner that no two successive spirals
are in contact with each other.
In consequence of this winding, I am enabled to place upon the non-conductor a
very large amount of wire, so that the wire at all points is entirely insulated and so
that a current traversing this wire cannot be short circuited between any two
parts of the winding.
By this method of arranging my wire in the form of a spiral spring, I provide
for the expansion of the wire when heated, the wire instead of becoming loose
and bunching and thus short circuiting, remains tightly wound, the expansion
being taken up by the spring of the wire. If two adjoining spirals should by the
expansion be drawn into contact, there would be no appreciable loss of force,
simply one of the spirals would be interfered with.
There is no danger of two successive layers of spirals coming in contact with
each other, separated as they are by the insulating material, but if this should
occur, it would result simply in one of the layers being short circuited and no
appreciable injury would take place.
By my method of winding the wire, having but one point of the edge of each
spiral in contact with the insulating substance, and the spirals separated from
each other and the layers of spirals separated in their path along the non-conducting
substance, the air or liquid in which this winding may be placed can circulate
freely on all sides thereof.

page_text: Thus the insulating material is protected from excessive heat and the atmosphere
and liquid are in contact with the greater portion of the wire.
In this way I am enabled to place a very large amount of wire on a small
cylindrical insulator and thus obtain a very great amount of heat energy from the
electrical current.
My apparatus may be used in this form and connected between the poles of an
ordinary dynamo, so that the current of electricity will pass through the long
spiral and cause the wire to become heated.
It is advisable to coat the wire with a suitable substance to prevent oxidation.
For this reason, I nickel plate the wire, or coat it with a substance to prevent
oxidation.
I place the cylinder containing the wire wound as described within the cabinet H,
which is provided with a box open at the bottom, raised a short distance from the
floor of the apartment, as shown in Figs. 1 and 2, and provided along one side
with a wire screen J extending from the top of the box downward a short distance
in order to allow for a circulation of the air from beneath the box, as shown by
arrows in Fig. 2. In this way, I protect the heater from coming into contact
with the occupants of the apartment in which it is placed, and provide for the
atmosphere circulating about it and becoming heated.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1st. In an electric heater, a wire wound in the form of a spiral spring extending
in a spiral path about a cylindrically formed non-conductor, in such a manner that
each spiral shall come into contact with the non-conductor at one point only and
the layers of spirals shall be separated from each other, substantially as described
and for the purpose set forth.
2nd. In an electric heater, the combination of an insulating substance, a wire
coiled in the form of a spiral spring extending in a spiral path about said insulating
substance, a non-conducting material placed between the adjacent layers of the
said spring, substantially as described and for the purpose set forth.
Dated this 13th day of June 1893
JAMES FINNEY MCELROY.
R. Haddan,
Herbert Haddan & Co.,
18, Buckingham Street, Strand, London, Agent for Applicant..