US2528503A - Electric heater - Google Patents

Description

Nov. 7, 1950 o. L. DILWORTH 2,528,503

ELECTRIC HEATER Filed Sept. 21, 1945 INVEN TOR. 0770.11. D/L WORTH.

BY p46; Z/Zu' HTTORNEY.

Patented Nov. 7, 1950 UNITED STATES PATENT OFFlCE- ELECTRIC HEATER Otto L. Dilworth, Hartford, Conn.

Application September 21, 1945, Serial N 0. 617,750

3 Claims. 1

This invention relates to electric heaters and has for an object thereof the provision of an electric heating element which is adapted to produce a maximum degree of heating in proportion to its size and with a minimum amount of current consumption.

A further object of the invention is to provide a novel heating element adapted for utilizing the effects of radiation to increase the heating capacity of the element.

Further objects and advantages of my invention will be more clearly understood from the following description and from the accompanying drawings in which:

Fig. 1 is a side view, partly in central vertical section, of an electric stove embodying m invention.

Fig. 2 is a bottom view thereof on line 22 of Fig. 1.

Fig. 3 is an enlarged view showing the arrangesection, of the oxygen consumer.

Fig. 6 is a plan view of my improved stove with the upper cover and plate removed.

Fig. 7 is a fragmentary side view, in central vertical section, of an insulated connector used in my improved stove.

As illustrated in the drawings, my improved stove may comprise a casing constructed of a base upon which is supported a frame 6 that is enclosed within an inner shell 1 having integrally therewith a top 8 and a plurality of lateral fins 9, preferably surrounded by a screen or perforated shell ID. If desired, the top 8 may extend over said perforated shell to retain it in position upon the base 5.

The said stove may be supported upon a suitable stand comprising legs l3 which may be secured within a base ring M as shown.

My invention also includes a novel heating element, preferably in the form of a coil [5, which is wound upon suitable refractory spools l6 and I! that are supported in the frame 6 by means of bolts l8 extending therethrough. At one side of each of said spools, I provide a copper disc I9 for the purpose hereinafter set forth.

One end of the said heating element is electrically connected to a set of binding posts 20 mounted on a conductor bar 20-a and the other end of the element is connected to a set of similar posts 2| mounted on the conductor bar 2 I-a. The said posts are each mounted on an insulated connector having a binding post 22 that extends through the base 5 and is constructed as shown in Fig. 7, wherein the base 5 has a depending flange 23 through which extends the post 22 that is insulated from the base by means of a resilient insulating material, such as asbestos or glass fiber, shown at 24 and which is compressed by means of a washer 26. The opening in the base is sealed by said asbestos and also by a suitable insulating washer 21 upon which is mounted a spacer 28 that supports the conductor bar a or 2 a.

As illustrated, the ends of the resistance Wires in the heating element coil [5 are connected to the binding posts 20 and 2| and an electric supply cord 29 is connected with one Wire 30 extending to the binding post 2| and the other wire 30a extending to the conductor bar 2I-a through a suitable heat responsive control, such as a thermostat 3|, which may be. of a well known construction and which is responsive to heat in the stove for controlling the electrical circuit for the operation of the heating element. The said thermostat 31 may be adjusted, by means of a knob 33, for the amount of heat desired and may also be adjustably positioned nearer to or farther from the base 5 so that the responsiveness of the thermostat to the heat from the stove may be selectively changed to further regulate the operation of the heating element for the amount of heat desired.

As shown, the thermostat 3| may be carried by a lever 34 which is pivoted at 35 and may be swung on said pivot and then looked in the desired position by suitable means, such as a nut 36, to retain the thermostat in the desired adjusted position which may be indicated by graduations 31, preferably on the base 5, registering with a pointer on a dial plate 38 that is carried by the thermostat 3| and has graduations registering with a pointer on the knob 33. It is pointed out that when the said thermostat is positioned further away from the base 5, it will be less responsive to theheat from the stove and therefore will permit the stove to operate at a higher heat than when the said thermostat is located closer to the base.

An important element of my invention is the novel means which I have provided for increasing the heating capacity of the heating element coil i5. This is accomplished by uniting a plurality of individual strands of wire 39, or ribbon, by

plaiting or braiding them together, as shown in Fig. 3 or otherwise, so that they will form a single resistance wire having a plurality of individual strands which are in close proximity with each other and in contact at spaced points. The resistanc wire or plait formed by the said strands is then wound into a spiral soil which is in turn wound upon the supporting spools l6 and ii as shown. After the element is so constructed, it will comprise a coil, as shown in Fig. 4, within which each turn, or loop, will include separate strands that are bound together in close proximity but in contact with each other only at spaced points.

In the operation of my invention, the electric current is supplied through the conductor 30 of the cord 29 to the heating element and from said heating element, through the conductor 3l-a. and the thermostat 3| to the other wire 30a of the said cord.

The efficiency of the heating element is greatly increased by the provision of the multi-strand wire since, when the said heating element is energized and heated, there is caused a compounded radiation which is due to the proximity of the individual strands 39 that is maintained by the spaced points of contact between said strands and which serves to create additional heating of the resistance wire as has been proven by numerous tests and experiments that have been carried out.-

It is commonly known that when a wire is energized it becomesheated and therefore it radiates heat. The hotter the wire, the more heat it radiates. It isalso known that when a plurality of heated wires are placed near each other, each tends to-heat the other by radiation. Therefore, by plaiting the strands together, as above described, and energizing them individually and in parallel within the electric circuit,I provide a single resistance wire in the form of a plait, or braid, having a plurality of 'strands'retained in proximity to eachother, whereby each strand tends to heat the other by radiation so that the temperature of each strand-is thereby raised and the heating element will give off a maximum amount of heat for any given amount of electric current. I

It will be understood, therefore, that by uniting the strands as above stated, myinvention provides a heating element having a resistance containing a plurality of strands each radiating heat upon the other and thereby effectively producing compound'radiation within the resistance which will greatly assist in raising the temperature of the heating element so that it will produce more heat without additional consumption of electric energy.

In the structure shown, the shells i and the cover 8 are integrally constructed and the said shell is hermetically secured to the base 5, by soldering or welding, as at 40, so that the chamber within said shell is sufficiently air tight to prevent the entry of air into said chamber and 4 around the heating element which operates therein.

If desired, the oxygen may be removed from the chamber by bleeding the said chamber with an air pump. For this purpose, there is provided a bleeding valve 42 which is connected to a nipple 33 to which may be attached a suitable pump. When the air is removed, the valve 42 is closed.

From the above it will be clearly understood that my invention provides a novel heating ele ment for electric stoves and the like which is capable of producing an additional amount of heat in proportion to the amount of electric energy consumed and which may be of types other than the open resistance type of heating element herein described without departing from the scope of my invention.

I claim:

1. For an electric heater of the character described, a heating element comprising an insulating support, and a resistance including a plurality ofstrands which are plaited together, formed into an elongated coil, and then said coil wound around said support, with adjacent turns of the coilspaced from each other, and connected in parallel within an electric circuitj whereby heating of said strands will cause radiation from each strand onto the others and increase the heating efficiency of the element.

2. For an electric heater,a heating element comprising an insulating support, and a resistance including a plurality of strands which are plaited together, then formed into a coil, and then said coil wound upon said support with adjacent turns of the coil spaced from each other.

3. The method of manufacturing an electric heating element which comprises the steps of plaiting a plurality of strands, coiling said plaited strands into an elongated coil to form a resistance for said element, and then winding said coil around a support of insulating material with adjacent turns of the coil spaced from each other.

- OTTO L. DILWORTH.

REFERENCES CITED The following references are of record in the file of this patent: I

' UNITED STATES PATENTS Obermaier 1 Sept. 2'7, 1938

Images