US643744A

US643744A - Electric heater.

Info

Publication number: US643744A
Application number: US70879499A
Authority: US
Inventors: Gardner C Hawkins; George E Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1899-03-13
Filing date: 1899-03-13
Publication date: 1900-02-20
Anticipated expiration: 1917-02-20

Description

No. 643,744. Patented Feb. 20, I900. G. C. HAWKINS.

ELECTRIC HEATER.

(Application filed Mar. 13, 1899.)

(No Model.;

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GARDNER O. HAWKINS, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO GEORGE E. SMITH, OF SAME PLACE.

ELECTRIC HEATER.

SPECIFICATION forming part of Letters Patent No. 643,744, dated February 20, 1900.

, Application filed March 18, 1899. Serial No- 708,794. (No model.)

To all whom, it may concern.-

Be it known that I, GARDNER O. HAWKINS, of Boston, county of Suffolk, State of Massachusetts, have invented an Improvement in Electric Heaters, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention has for its object the production of a novel electric heater adapted for use in cars, steamships, dwellings, factories, &c., the same being so constructed that it may be easily mounted in working position and when started may be made to heat the air in the room or apartment where the heater is located.

Myimproved heater consists, essentially, of

1 a surrounding case, preferably of sheet metal,

suitable resistance medium or coils sustained within the delivery end of said case and 0ceupying a position at or near the delivery end of said shell, said resistance medium or coils occupying a position between the inner wall of the case and the center of rotation of the motor-shaft, and an electric motor carrying a fan adapted to suck air into said shell at or near the base thereof and force it over the re sistance medium or coils, said air being heated on its way through said shell and out from its open or delivery end. Each resistance medium or coil presents a surface of considerable diameter, and they are preferably arranged in a circle, and the fan cooperating with the resistance medium or coils is so constructed and actuated by the electric motor that said fan blows the air diagonally out-.

ward across the heated resistance medium or coils, and also, due to the circular current established in the air within the case by the fan, it results that the air is made to impinge against a very large portion of the cylindrical exterior surface of the resistance medium or coils, and the greater the surface of the resistance medium or coils directly impinged or struck by the blast of air the greater the quantity of heat taken up by the air therefrom. The fan is carried by the shaft of an electric motor located centrally within the case, the motor being preferably inclosed in a shell, the fan standing and turning, preferably, in the case between its ends, one end of the case being open for the discharge of air, whereas the case at or near its opposite end has suitable air-inlets.

Figure 1, in vertical section, shows an electric heater embodying myinvention. Fig. 2 is a view of the same looking into its delivery end, the resistance-coil H being mostly broken out. Fig. 3 shows part of one of the resistance-coils detached and enlarged.

The electric-motor shaft a carries a suitable armature which revolves within the usual field, and this shaft and field, which may be of any usual or suitable construction, are sustained in a suitable shellb b. The said shell, as herein shown, is composed of two semispherical parts, each having a flange, as b and b the flange 72 resting on a series of posts b extended from a base b Thefiange 1) receives upon it the flange b and suitable screws b extended through said flanges, serve to confine the semispherical parts of the shell in position on said base.

The electric motor is not of my invention, and I may employ any of the usual forms of electric motor. The fan carried by the shaft a may, however, for the best results have a construction which I will now proceed to describe. This fan is composed of a suitable bottom plate a, the hub of which may be secured to the shaft a by a suitable set-screw c and two inclined circular walls 0 0 connected by blades 0 so that said walls and blades constituting the fan are made to travel in unison with said bottom plate. These walls occupy a position each with relation to the other substantially concentric, (see Fig. 1,) and, as herein shown, the said walls are inclined outwardly away from the center of motion of the shaft a. The blades a represented as six in number, are suitably riveted at their ends, respectively, to the walls 0 0 The fan so made presents two circular walls open at bottom and top and connected across by the blades. The motor and fan are surrounded by and rotate in a case d, having bolted to it at one end a flanged ring cl. open at its outer or delivery end and has at or near its opposite end, preferably below the plane in which the fan rotates, a series of inlet-passages d for the entrance of air which is sucked into the case to be heated, said air The case isbeing driven through the case into the room or apartment and over the resistance medium or coils to be described.

The resistance medium or coils 6 shown are substantially cylindrical in cross-section, and theypresent a heated surface of considerable diameter in cross-section.

The resistance-coils e are represented as six in number, and they are composed of a series of porcelain or other insulating tubes 6, (see Fig. 3,) Wound externally with fine Wire 0 said tubes being supported on suitable studs or carriers e herein represented as sustained by the metallic case CZ within its open end, said tubes being retained on said studs by suitable cotter-pins e or otherwise. These resistance-coils are connected together in series, as best represented in Fig. 2, by a series of wires connecting the tubes, and the currentcomes into the resistance-coil through a feed-wiref.

By increasing the area of the heated surfaces of the resistance-coils the heat may be greatly augmented, and to provide for this I have provided a resistance-coil H, it being composed of a flat ring h, of porcelain or other insulating material, wound with fine wire h, said wire being suitably connected in circuit with any usual source of electric supply. The resistancecoil II may be supported on arms 7L3, sustained by the shell d at suitable points, said coil being represented as set at an inclination, so that the blast of air heated by the fan after crossing the coils 6 may impinge directly against the inclined surface of the coil II and be thrown back again across the coils e, &c. These resistance-coils may be of greater or less diameter and strength, and they are preferably so located as to stand between the center of rotation of the face and the inner wall of the case and in the path of the air-current generated by the fan.

It will be understood that the air is heated by being impinged against the heated surfaces of the resistance-coils, and realizing this I have constructed the resistance-coils so that they present a cylindrical mass of Wound wire of considerable diameter, thus making them more serviceable for heating than would be a series of strands of wire stretched across within a tube or frame. The fan shown, it being located within the case and rotating in a plane between the air-inlets of the case and the open end or outlet thereof, creates an air-current which is defined by a combined outward and circular movement, such a current of air established within the case impinging against a substantially large area of the heated resistance located within said case.

In my judgment,derived from experiments,

I find that the mere circulation of air about a resistance-coil without direct impingement by a fan or blower does not enable the air to take any great amount of heat from said coil. This invention is not limited to the exact number of blades in the fan nor to the exact number of resistance-coils employed,and

I may employ any desired number of blades or coils, nor is the invention limited to the exact manner shown for supporting the said resistance-coils, but it is preferred to support them by or through studs carried by the case, and it is also preferred that the free ends of the coils 6 point toward the center of rotation of the fan.

It will be noticed that the shaft a outside of the shell I) b carries only the fan and is not burdened by any wire constituting part of a resistance medium to supply heat.

I provide the interior of the case 61 at a point just below the lower end of the fan with a stop-plate m, which acts to prevent the air from coming into the case from its open end, said plate aiding in inducing the flow or current of air from the inlets (1 into the inlet of the fan and therefrom through the outlet end of the shell.

Preferably the exterior diameter of the fan is but little smaller than the interior diameter of the case, so that the space between the rotating fan and the interior of the case is substantially closed, thus preventing air from coming into the case, due to back draft of the fan.

Vhile I prefer metal for the case, yet this invention is not limited to the use of metal, as I may employ any other suitable material.

By the term resistance medium used in the claims I intend to cover any form of resistance-coil having a surface composed of wire wound about it as contradistinguished from wires crossing each other singly, like a seive or network.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an electric heater, a surroundingcase, a series of resistance mediums composed of Wire wound about an insulating-core and located within said case and occupying aposition at or near the delivery end thereof, said resistance mediums surrounding the center of rotation of the motor-shaft, an electric motor carrying a fan adapted to draw air into said case at or near its base, and force said air as ablast over the resistance medium, said air being heated on its way through said case to its delivery end, the construction and arrangement of parts being such as to establish air-currents which are defined by a combined whirling and outward movement,whereby the airis subjected to the repeated heating action of the heating mediums, substantially as described.

2. In an electric heater, a surrounding case, a series of resistance mediums composed of Wire wound about an insulating-core to present a surface of considerable diameter, said mediums being exposed in said case, a fan composed of a plurality of inclined circular walls connected by blades, an electric motor to revolve said fan and create a blast of air which is delivered diagonally outward across said resistance mediums and is also made to travel about in said case to thereby impinge the air against a large portion of the exterior of said resistance mediums from different directions, substantially as described.

3. In an electric heater, an external case open at its outer or delivery end and adapted to receive air opposite or at its air-receiving end, an electric motor located in said case and carrying a fan which rotates in said case between its air-receiving end and its air-delivering end, a resistance medium contained Within said case between its air-receiving and air-delivering ends, said resistance and said motor each deriving their electrical energy through independent wires, the construction and arrangement of parts being such as to establish air-currents which are defined bya combined outward and circular movement of the air within the case, said current impinging against a substantially large area of the heated resistance medium in said case, substantially as described.

4. In an electric heater, a surrounding case open at its outer or deliver end, and adapted to receive air at or near its opposite or airreceiving end, an electric motor located in said case and carrying a fan which rotates in said case between its air-receiving end and its delivering end, and a resistance-coil composed of a ring wound externally with wire, and means to support said ring inside of but removed from contact with the interior of said surrounding case between its air-receiving and air-delivering end, the blast of air. created by said fan having access to the entire exterior surface of said resistance-coil, substantially as described.

5. In an electric heater, a surrounding case open at its outer or delivery end and adapted to receive air at or near its opposite or air-receivin g end, an electric motor located therein and carrying a fan which rotates in said case between its air-receiving end and its air-delivering end, and a resistance-coil composed of a ring of insulating material occupying an angular position within said surrounding case and covered with a fine wire, the blast of air created by said fan impinging directly against said wire, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GARDNER G. HAWKINS.

Witnesses:

Gno. W. GREGORY, MARGARET N. DUNN.