US1756444A - Electric heating means - Google Patents

Description

April 29, 1930. R. voN BRocKDoRFF 1,755,444

ELECTRIC HEATING MEANS Filed Feb. '7. 1929 Sie Patented Apr. 29, 1930 UNITED STATES .RUDOLF VON BROCKDORFF, OF MUNICH,v

PATENT OFFICE GERMANY, ASSIGNOR TO SCHUTTE A NI) PENNSYLVANIA ELECTRIC HEATING MEANS Application lfiled February 7, 1929, Serial No.

My invention relates to electric heating fneans wherein one or more electric heating coils of novel construction is or are supported by suspension or otherwise within a chamber to be heated, or within a chamber of an (element the latter being the heat radiating means of the heater structure.

The general object of the invention is to provide a heating means comprising one or more coils or helices through which current is adapted to low and which coils are provided with means whereby the inductance thereof is reduced the said means also operating to prevent objectionable humming noises when alternating current is supplied.

It also is an object of the invention to provide the coils with means of novel construction whereby pressure is adapted to be applied axially thereto'to compensate expansion and contraction changes due to variations in temperature.

In order that the invention may be readily understood and its practical advantages fully appreciated reference should be had to the accompanying drawing in which I have illustrated a coil embodying the invention and certain applications thereof to practical uses.

In the drawing Fig. 1 is a view in elevation of a coil constructed in accordance with the invention;

Fig. 2 is a longitudinal sectionalview of a tubular member having a plurality of coils mounted in series therein, the heatin of which is adapted to effect heatingo the tubular member which acts as a heat radiating element;

Fig. 3 is a view in transverse section taken on the line 3-3 of Fig. 2; Fig. 4 is a view in longitudinal section similar to that shown in Fig. 2 but illustrating 338,141, and in Great Britain June 16, 1928.

b er, such as the fuel chamber of a stove, which is to be heated; or the said coil or a plurality of such coils may be mounted within a hollow member of tubular character and a current caused to iiow therethrough for heating the said member, the latter operating as the heat radiating element of the heating structure.

One form of heating coil or helix embodying my invention as illustrated in the drawing comprises a coil or helix 1 of small diameter in which theturns of the coil are located in contact with each other. The adjoining contacting turns of the coil or helix 1 should be insulated from each other so as to prevent short-circuiting between the said turns, and to this end the wire of which the coil is formed may be covered with an oxide of the metal of which the wire consists or other oxide of suitable character which possesses the requisite qualities of insulation. The wire of the coil or helix l is extended at its opposite ends and is employed in the formation of terminal coils or helices 2 and 3 of large diameter as compared with the diameter of the coil or helix 1. The turns of these coils or helices 2 and 3 are separated from each other as indicated,

and thesaid coils or helices are wound in directions opposite that of the winding or coiling of the coil or helix l. The purpose of reversing the directions of the turns of the coils or helices 2 and 3 with respect to the direction of the turns voit' the coil or helix 1 is to reduce the inductance of the structure and alsofto prevent or at least reduce objectionable humming noises which otherwise would be present. By providing a helix 1 of small diameter the magnetic iux there: through is relatively small whereby the inductance is reduced' and also singingl noises which otherwise might be present are reduced. The coils or elices 2 and 3 not only serve as means to reduce the inductance of the element but they also serve as means for oyieldingly holding or suspending the helix 1 and for protecting the element against shocks to which they may be subjected when shipped by the ordinary means lof transportation. The said coils 2 and 3 also operate to compensate for changes in length of the helix 1 due to variations in, temperature.

relatively to each other and thereby become ltelescoped, as it were, in relation to each other. The heating coil 1 is of relatively rigid structure so that when it is supported at its opposite ends no intermediate support or steadying means is required.

In Fig. 2 of the drawing I have shown a plurality of heating coils of the character of that shown in Fig. l mounted within a tubular member 5 which is adapted to be heated by heat radiated from the said coils, the said tube 5 becoming theheat radiating element of the structure. The metal tubular member or element 5 is closed at one end by an integral portion 6, as indicated, and its opposite end is closed by a plug 7 of insulating material such as steatite, which is secured in place by means of fastening screws 8. A couple of metal bars 9 are secured to theirner side of the plug 7 and extend throughout the greater portion of the length of the tubular member or element 5. Crosswise extending metal bars 10 and blocks 1-1 of insulating material, such-as steatite, are mounted atintervals upon the said bars 9, the said bars 10 and 11 being arranged in co-uples and located upon opposite sides of the bars 9 and being secured in place upon the latter by means of fastening bolts 15. In the construction as illustrated there are three of these couples of members 10 and 11, but it will be understood that the number of such couples may be increased or diminished within practical limits if desired. One of the blocks 11 of insulat- 404 ing material is provided, in the construction shown, with a couple of transversely extendmg notches 16 of rectangular sha-pe within which aremounted metal blocks 17 of suitable metal, such as brass. These blocks are provided with holes or openings 18 extending therethrough in directions parallel with the axls of the tubular member or element 5.

The plug 7 of insulating material is provided With a couple of openings 20 which lead from the outside into the interior of the tubular member or element 5. These openings are provided with tubular linings of suitable insulating material 21 through which extend wires 22 and 23 to the outer ends of which 55 are connected terminal blocks 24 and 25. These terminal blocks are provided with- `holes 26 which extend transversely therethrough, into which holes the ends of conducting wires 27 and 28 are adapted to be inl --serted and 'held in place by binding screws or posts 29. v

. The inner ends of the wires 22 and 23 project into the outer ends of the holes 18 in the blocks 17 mounted upon the firstof the insulating blocks 11 and are secured therein by means of binding screws 24. The wire at the opposite ends of each of the heating elements is extended as indicated at 30, andthe outer ends of these extensions project into the opposing ends of openings 18 in the blocks 17 It will be noted that there are two of the'heatingunits located in parallel relation to each other between the adjoining blocks 11 of insuit will-flow through theheating elements in series and that all of them will be heated to an extent depending upon the energy of the current flowing therethrough and that the heat therefrom will radiate therefrom and result in the heating of the tubular member or element 5 from which the heat ris radiated into a room or into any other chamber within which the said member 5 may be located. It will be noted that the brass blocks 17 are located considerable distances from the heating elements consisting of the coils 1 and the extensions 2 and 3 thereof, in consequence of which they are without the zones of greatest heat intensity. Hence destruction thereof by the application oftoo high heat thereto is avoided.

In Fig. 4 of the drawing I have shown a construction comprising a tubular member or element 5 within which are mounted at intervals blocks 40 of insulatin material through which holes 41 of relative y large diameters are provided. The heating member of this structure comprises a wire 39 having at intervals helices 1 of small diameter, similar to the helix 1 shown in Figs. 1 and 2 of the drawing. The turns of the helices 1 are lo-pv cated in contact Witheach other, as shown. The said wirealso'is provided at intervals with coils or helices 42 of relatively large diameter, the turns of which are separated as shown. In the construction as illustrated the two intermediate coils 42 of large diameter helix 42 through the tubular member 43 mounted in an opening44provided in the block 45 of insulating material which is secured to and closes one end of the tubular member 5. The outer end of the said wire is provided with a terminal block 46 havin@ an opening therethrough into which one endbf a conductor 47 projects.` A binding screw 48 holdsl the said conductor in place in the said opening. The wire at the inner end of the innermost coil 42 is extended and is threaded through openings 50 provided in the blocks 40 and is finally threaded through a tubular lining member 51 of insulating material mounted in an opening 52 provided in adjoining relation to the opening 44. The outer end of the said extension Wire is provided with a terminal block 53having an opening therein into which one end of a conductor 54 extends. The said conductor is held in said opening by means of a binding screw 55. The coils orhelices 42, with their' turns spaced or` separated from each other as shown, yield so as to permit expansion and contraction of the coils or helices l due to variations in temperature. It will be noted that the turns of the wire which form the coils or helices 42 extend in directions opposite that in which the turns of the wire of the adjoining coils or helices 1 extend. The purpose of such reversal in the direction of the coils has been fully set forth and described in connection with the description of the coils illustrated in Fig. I.

In Fig. 5 of the drawing I have shown a structure `comprising' 'a coil or helix 1" in which the turns are located in contactual relation with respect to each other. The lower end of the coil or helix 1 is extended and is connected to a terminal 56 to which a conductor 57 is connected and heldy by means of a binding screw 58. The wire at the o posite end of the `oil or helix 1" is extende as indicated at 60, and is connected to one end of a lever 61 pivoted intermediate its ends to a support 62. The opposite end of said lever is connected to one end of a coiled spring 63 which tends to contract, the opposite end of said spring being connected to a stationary support 64. l It will be seen that the spring 63 exerts continuously a pull upon the outer end of the lever 61 tending to cause inward movement of the inner or o posite end thereof. The extension 60 prevlously referred to is connected to one end of a wire conductor 65 the opposite end of which is connected to a binding post 66 mounted upon a support 67 l of insulating material.

A'The heating elements in the several forms of construction may consist of any suitable metal but preferabl an alloy of chrome-nickel Iis employed. Tliis alloy, by reason of its high specilic resistance and resistance to heat, is particularly suitable for the construction of the heating elements employed for heating by radiation. y

It willbe seen that by my invention I have provided a heatin element consisting of a heating coil or helix of small diameter with the turns thereof in contact with each other, the opposite ends of which helix are provided with or terminate in oppositely wound coils or helices of relatively large diameters which are adapted to yield upon variations in the length of the coil or helix of small diameter due to variations in temperature and also it will be seen that I have provided heating structures embodying said coils or helices in cooperative relation with respect to each other. i

Having thus described my invention, what I claim and desire to secure by Letters Patent is An electric heating means, comprismg a wire having helical portions of relatively small diameter at intervals therein, and the said wire also having helical portions of rela.- tively large diaineterlocated alternately with respect-to the first named portions, the turns of the rst and second named portions extending in reverse directions with respect to each other, means for insulating the adjolnmg turns of the saidcoils from each other, and means having connection with said heating means at its opposite ends and constltuting the sole means of support therefor.

In testimony that I claim the foregolng as my invention, I have hereunto slgned my name this 11th da of December, 1928.

RUDOLFyvoN BROCKDORFF.

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