US 2806931 A
Description (OCR text may contain errors)
. INVENTOR. 6057/7 C" HKEPLQF cs.v c; AKERLOF ELECTRICAL HEATING DEVICE Filed Sept. 22.l 1952- Sept. 17, 1957 United States Patent O 2,806,931 ELECTRICAL HEATING DEVICE Application September 22, 1952, Serial No. 310,818
S Claims. (Cl. 219-19) This invention relates to heating devices and is directed particularly to a method and means for producing heat through the direct utilization of high-voltage electrical energy.
Electrical devices commonly used for a variety of heating purposes comprise low-voltage high-current resistance wires or coils. Because of the high currents required in such heaters, heavy wiring must be provided both to keep line losses low and to minimize the possibility of fire. Other disadvantages in the use of resistance wires or coils Ias heaters are that they are subject to breakage and burning out.
Accordingly, one object of this invention is to provide a method and means for producing a novel heating device operative directly from a high-voltage source.
Another object is to provide a device of the above character having no wire or coil resistance elements or other parts subject to deterioration or breakage in use.
A further object is to provide a method of utilizing high-voltage electrical energy to produce heat that is readily adaptable to the production of heating units of a variety of sizes and shapes.
A further object is to provide a heating device of the above nature that is rugged, eilicient and has a long useful life.
Other objects and many of the attendant advantages of this invention will readily be appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing, wherein:
Fig. 1 is an elevational view, in cross-section, of a typical embodiment of the novel heating device disclosed herein, and
Fig. 2 is a horizontal cross-sectional View of Fig. l taken along the line 2-2 thereof.
As known to those versed in the art, the electrons in a non-isothermal electric plasma created by a high-voltage discharge in space follow accurately a Maxwellan velocity distribution. The electron temperatures corresponding to measured electron velocities in such plasma are often surprisingly high, values of 80,000 C. having been observed. Briey, this phenomenon is utilized in the present invention by forcing such high-velocity electrons to go through a porous, non-electrically conductive layer of material, whereby the thermal energy of the electrons is transferred to the porous material to heat it uniformly without formation of an electric arc.
In the drawing, wherein like reference characters denote corresponding parts in each of the two views, the numeral indicates a porous, non-electrically conductive tubular member, closed at one end, preferably formed of unglazed porcelain. Extending axially within the porous member 10 is a rod-like metallic electrode 12, held in place therein by Aan insulating bushing 14 pressfitted Within the open end thereof. A circular base member 16 of insulating material is fixed against the open end of the porous member 10 in coaxial relation thereto, said base member being provided with a central opening for passage of the outwardly extending end of the electrode 12. A metallic tube 18, closed at one end, envelops the porous member 10 and is fixed with respect thereto by having its open end crimped about the outer periphery of the circular base member 16. The diameter of the base member 16 is somewhat larger than the outside diameter of the porous member 10, so that the inner surface of the outer cylindrical tube 18 is held in uniform spaced relation with respect to the outer surface of the porous member.
The heater unit is evacuated of air and substitution made of a small amount of a noble gas such as argon.
Electrical connection is made through conductors 20, 22 carrying the output of a high voltage power source 2.4 to the electrode 12 and the outer metallic tube 18, respectively.
Operation The application of a source of voltage suiciently high to create an electric discharge ield within the heating device causes electrons to collide with the walls of the pores of the porous member 10, with the result that the thermal energy of the electrons is transferred to the porous member. This heat is radiated to the outer metal tube 18 to provide an evenly heated unit. The amount of heat evolved is a function of the voltage applied, the type of current being immaterial.
Although the particular embodiment of the invention described herein is tubular, it will be evident that the principle disclosed is as readily applicable to other shapes of heating devices. Thus, the inner and outer electrodes and the central porous member comprising the device can be disk shaped, to provide a disk-like heater suitable, for example, in electric stoves. Obviously, many modiiications of the present invention are possible in the light of the above teachings, and it is therefore to be understood that within the scope of the appended claims, the invention can be practiced otherwise than as specifically described.
1. An electrical heating device comprising a first electrode, a second electrode ixed in spaced relation with respect to and encasing said lirst electrode, a porous, non-electrically conductive member disposed Within the space defined by said first and second electrodes encasing said first and encased by said second electrode, an atmosphere of a noble gas only, under low pressure, in the space between said -irst electrode and said porous member, and a high-voltage source connected to said electrodes to create an electric plasma between said electrodes.
2. The invention as defined in claim 1 wherein said porous member comprises unglazed porcelain.
3. An electrical heating device comprising an elongated cylindrical electrode, a tubular electrode surrounding said cylindrical electrode, coaxial with respect thereto and defining a space therebetween, a porous, nonelectrically conductive member fixed within the space between said electrodes, an atmosphere of a noble gas only, under low pressure, in the space between said lirst electrode and said porous member, and a high voltage source connected to said electrodes to create an electric plasma between said electrodes, whereby electrons, in migrating from one electrode to the other, will collide with the walls of the pores of the porous member to generate heat therein.
4. The invention as delined in claim 3 wherein said porous member comprises unglazed porcelain.
5. An electrical heating device comprising a nonelectrically conductive unglazed porcelain tubular member, closed at one end, an insulating bushing press-fitted in the other end of said member, an insulating base member abutting said bushing and the other end of said member and extending radially beyond the major diameter of said member, a first electrode extending axially within .said member in spaced relation to said member and through said bushing and said base member, a second electrode secured to said base member in spaced relation to and encasing said member, an atmosphere of a noble gas only, under low pressure, in the space between said iirst electrode and said member, and a high voltage source connected to said electrodes to create an electric plasma between said electrodes.
References Cited in the file of this patent UNITED STATES PATENTS White Feb. 22, Audain June 30, Clark Dec. 13, Berghaus et al. Dec. 23, Rummel Dec. 30, Depp May 16, Godley May 29,