|Publication number||US2939807 A|
|Publication date||Jun 7, 1960|
|Filing date||Jun 29, 1956|
|Priority date||Jun 29, 1956|
|Publication number||US 2939807 A, US 2939807A, US-A-2939807, US2939807 A, US2939807A|
|Inventors||Needham Basil A|
|Original Assignee||Thermway Ind Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (14), Referenced by (53), Classifications (14)|
|External Links: USPTO, USPTO Assignment, Espacenet|
June 7, 1950 B. A. NEEDHAM 2,939,807
METHOD OF MAKING A HEATING PANEL Filed June 29. 1956 /7 f TQFNIK United States O.
METHOD OFMAKING A HEATING PANEL Basil A. Needham, Bayside, N .Y., assgnor to Thermway Industries, Inc., New York, N.Y., a company of Delaware Filed June 29, 1956, ser. No.s94,s34 t 4 claims. (ci. 111-212) This invention relates to heating devices and particularly to an improved electrically energized radiant heating element and the method of making it.
An object of the invention is to provide an improved radiant heating element suitable for use in space heating panels adapted to be mounted on the walls or ceilings of buildings, in portable heaters, and 'as a heating element for water heaters, ranges, etc. My improved element is also suitable for use in industrial applications.
Another object is to provide an improved radiant heating element whichv is self supporting, has inherent rigidity, yet is rugged in construction and not easily subject to damage by mechanical or heat shock.
Still another object is to provide an improved electrical heating element wherein the resistor is fused on a self supporting backing member which may be llat or curved and wherein the resistor presents a relatively large area of heating surface.
Another object of the invention is to provide an improved electrically tenergized heating element of sheet form which includes ya metal sheet with a resistor element mounted thereon suitably insulated from the metal sheet, and which has a vitreous or porcelain enamel coating on the front surface of the sheet for diffusing the radiation thereof.
Other objects and advantages of the invention will become apparent from the following specification which describes preferred embodiments of the invention.
In the drawing accompanying the specification,
Fig. l is a rear view of my improved heating element with a portion of the protecting coating broken away to show the resistor;
Fig. 2 is 1an enlarged section taken on the line 2-2 of Fig. 1; and
Fig. 3 is a section, similar to Fig. 2, of a modified form of element.
Referring to Figs. l and 2 of the drawing, it may be seen that my improved heating element comprises a sheet which is preferably of metal but may be of other suitable material. The sheet 10 may be of any desired thickness so long as it is self supporting and substantially rigid. Generally, met-al of sufficient section to provide the desired characteristics with lightest weight is used. While the sheet 10 is shown as at and rectangular, any regular or irregular shape may be used and the sheet may be formed into a cylinder or other shape.
The sheet 10 is coated with a layer of frit, vitreous enamel or porcelain enamel 12, and an electrical resistor 14 is applied to the refractory coating as indicated at 14.
Terminal electrodes 16 are suitably soldered or otherwise attached to the resistor as shown. The other surface of the sheet 10 has a coating 18 of frit, vitreous or porcelain enamel, and preferably the rear (element carrying) side is coated with a layer 20 of corrosion retardant material such as silicone enamel, melamine resin, or the like.
The coating 20 protects the rear surface of the panel generally and prevents corrosion of the resistor 14 which might occur from exposure to air, water or a corrosive atmosphere. Such corrosion sometimes causes 4localized high resistance which, in turn, causes localized over heating and failure of the resistor.
Application of the vvitreous coating and the resistor presents some difiiculty because the element in use is subjected to rapid heating and cooling and it has been found that unless the various coatings are applied under careilly controlled conditions, chipping and spalling may result. Furthermore, unless the vitreous coatings are applied correctly warping of the element results and this is highly objectionable. Heating elements made in accordance with the method outlined herein have proven completely satisfactory.
A metal backing sheet 10 is first heated uniformly to approximately 1500 F. and the vitreous layers 12 and 18 are applied, preferably by spraying from a spray gun or nozzle, while the sheet lisrnaintained at the indicated temperature. The coated sheet is then carefully annealed and brought to room temperature slowly such that the coating or coatings do not spall and no warping of the element takes place. It is of prime importance that the vitreous coating be uniform in thickness, and if coatings are applied to both sides of the sheet, the thickness should be the sa'me for best results.
I have found that steel coated with porcelain to a uniform thickness of one-sixteenth of an inch on each surface is ideal for the heating element herein described.
The coated sheet is then cleaned, preferably in a vaporizing oven with a vaporized solvent, `and is reheated to a uniform temperature of 550-700 F. or somewhat higher and maintained at this temperature while the resistor 14 is applied. The latter may be pure aluminum or an alloy and is applied by spraying molten metal from a gun or nozzle to a thickness of .O05 inch. During application of the metal coating, the sheet is moved at a uniform rate past the gun which is oscillated vertically or horizontally.
The metallic coating 14 m-ay be sprayed through a mask to provide the grid-like path desired, but I prefer to lapply a uniform coating of metal on the porcelain then etch the grid pattern. Accordingly, a silk screen I pattern is placed on the hardened metal coating and a coating of silicone Varnish or resin is squeezed over the entire surface of the sheet. The element is then placed in an etching bath, such as a 2% nitric acid solution, for a time sufficient to etch the metal completely away in the places not covered by the enamel.
Next, the element is removed from the etching bath and dried whereupon it is complete, the silicone still adhering to the resistor pattern forming an anti-corrosive layer.
As illustrated in Fig. l, a border 11 of bare metal is preferably left around the margin of the sheet 10 on both sides. This uncoated border protects the coatings from being chipped at their marginal edges dur-ing handling and provides space for holes 13 which can be used to fasten the element in a frame or other support.
Fig. 3 shows a modification wherein the element above described is provided with an additional coating 22 on its rear side. This coating 22 may be of rock wool, foam glass, fibre glass, or other suitable heat insulating material, and improves the heat radiating qualities of the element by reducing rad-iation from the rear side which is generally against or close to the mounting surface, such ias a wall or ceiling.
In either form of the invention, the metal base sheet 10 may be of any suitable metal or alloy such as copper, aluminum, steel, etc. Stainless steel has approximately the same coecient of expansion as the vitreous enamel and therefore works very well. In general, it may be `PatentedJune7,1960
stated that the coeicients of expansion of the metal base y and the refractory coatings used should be approximately ment is heated and cooled. This requirement is, ofi
course, not so critical if it is intended to operatethe element at'fairly low temperature. For space'heating, electrically energized panels of the sheet-element type are :operated at temperatures of approximately 150" to 375 F. In industrial use, much higher temperatures are utilized.
' I claim:
1. The method of making an electrical radiant heater.
comprising, heating a metal sheet to approximately 15 00v F. and While maintaining the sheet at such temperature? applying lan insulating, hard, vitreous coating to bothv surfaces of said sheet, annealing said coated sheet, re-
heating said coated sheet to a temperature of approxi-A 4 surfaces of said sheet, annealing said coated sheet, reheating said coated sheet to a temperature of approximately 550 F. and While maintaining the coated sheet at such temperature spraying one of the coated surfaces with molten metal, then etching said metal to provide a grid-like pattern.
4. The method of claim 3k including the stepv of Y applying facoating of silicone varnish to said grid-like pattern.
References Cited in the ile of this patent UNITED STATES PATENTS 617,375 'Voigt Jan. 10, 1899 2,061,107 Schellenger Nov. 17, 1936 2,119,680 Long June 7, 1938 2,179,566 Stoekle Nov. 14, 1939 2,357,473 Jira Sept. 5, 1944 2,432,800 Reichold Dec. 16, 1947 2,441,960 Eisler May 25, 1948 2,486,148 Glynn et al. Oct. 25, 1949 2,502,291 Taylor Mar. 28, 1950 2,542,726l Sullivan Feb. 20, 1951 2,679,569 Hall May 25, 1954 2,695,351 Beck Nov. 23, 1954 2,739,085 McBride f.. Mar. 20, 1956 FOREIGN PATENTS 162,632 Australia Apr. 29,
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US617375 *||Dec 26, 1895||Jan 10, 1899||THE ROESSLER a HASSLACHER CHEMICAL COMPANY||Julius ferdinand heinrich voigt and jacob adolf haeffner|
|US2061107 *||Nov 2, 1934||Nov 17, 1936||Chicago Telephone Supply Co||Method of making resistance elements|
|US2119680 *||Jun 14, 1935||Jun 7, 1938||Saint Gobain||Method and means for the manufacture of electrical resistances|
|US2179566 *||Mar 5, 1936||Nov 14, 1939||Globe Union Inc||Resistor|
|US2357473 *||Jun 6, 1941||Sep 5, 1944||Continental Carbon Inc||Protective coating for resistors|
|US2432800 *||Mar 2, 1946||Dec 16, 1947||Silex Co||Heating element and method of making same|
|US2441960 *||Feb 3, 1944||May 25, 1948||Eisler Paul||Manufacture of electric circuit components|
|US2486148 *||Mar 19, 1946||Oct 25, 1949||Blue Ridge Glass Corp||Electric heating element|
|US2502291 *||Feb 27, 1946||Mar 28, 1950||Lawrence H Taylor||Method for establishing electrical connections in electrical apparatus|
|US2542726 *||Jun 30, 1945||Feb 20, 1951||Herbert W Sullivan||Method of forming inductor coils|
|US2679569 *||Aug 25, 1951||May 25, 1954||Electrofilm Corp||Electrically conductive film|
|US2695351 *||Jan 12, 1950||Nov 23, 1954||Beck S Inc||Electric circuit components and methods of preparing the same|
|US2739085 *||Mar 13, 1953||Mar 20, 1956||Westinghouse Electric Corp||Insulating coatings for magnetic sheets|
|AU162632B *||Title not available|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3026398 *||Apr 22, 1959||Mar 20, 1962||Gen Electric||Baseboard electric heating system and electric heating units therefor|
|US3057989 *||May 23, 1958||Oct 9, 1962||Thermway Ind Inc||Curtain wall|
|US3067310 *||Dec 2, 1959||Dec 4, 1962||William D Oliver||Microfilm electric heaters|
|US3071749 *||May 17, 1960||Jan 1, 1963||Budd Co||Adjustable resistors and method of making the same|
|US3072500 *||May 6, 1959||Jan 8, 1963||Motson Services Inc||Printed circuit|
|US3108170 *||Feb 17, 1958||Oct 22, 1963||Maxwell K Murphy||Heating element|
|US3109228 *||Aug 10, 1959||Nov 5, 1963||Thermway Ind Inc||Manufacture of electric radiant heating panels|
|US3126470 *||Dec 30, 1960||Mar 24, 1964||Electric water heating apparatus|
|US3174211 *||Jul 26, 1961||Mar 23, 1965||General Electric Company||Gaszak method of manufacturing a resistance-heating type water heater|
|US3177338 *||Jun 29, 1962||Apr 6, 1965||Smith Corp A O||Multi-operator resistor grid welding apparatus|
|US3197335 *||Apr 9, 1962||Jul 27, 1965||Stanley W Leszynski||Surface-mounted electrical resistance structure and method for producing same|
|US3202951 *||Aug 16, 1961||Aug 24, 1965||Krinsky Albert||Alloys and electrical transducers|
|US3231718 *||Feb 5, 1962||Jan 25, 1966||Akay Corp||Automatic electric food warmer tray|
|US3243313 *||Apr 25, 1960||Mar 29, 1966||Ling Temco Vought Inc||Heat-resistant article|
|US3252831 *||May 6, 1964||May 24, 1966||Electra Mfg Company||Electrical resistor and method of producing the same|
|US3259559 *||Aug 22, 1962||Jul 5, 1966||Day Company||Method for electroless copper plating|
|US3343329 *||May 14, 1964||Sep 26, 1967||Pohutsky Arthur J||Spacer-support clip for ceiling construction|
|US3349722 *||Nov 27, 1964||Oct 31, 1967||Cleveland Technical Ct Inc||Electrical resistance rail heater|
|US3370262 *||May 27, 1963||Feb 20, 1968||Sprague Electric Co||Electrical resistor|
|US3396055 *||Apr 16, 1965||Aug 6, 1968||Vitreous Steel Products Compan||Radiant heating panels and resistive compositions for the same|
|US3405381 *||May 4, 1965||Oct 8, 1968||Vishay Intertechnology Inc||Thin film resistor|
|US3505498 *||Jul 23, 1968||Apr 7, 1970||Minnesota Mining & Mfg||Cooking utensil with integral dielectric layer and electrical heating element|
|US3517436 *||Nov 1, 1967||Jun 30, 1970||Vishay Intertechnology Inc||Precision resistor of great stability|
|US3694623 *||Sep 3, 1970||Sep 26, 1972||Matsushita Electric Ind Co Ltd||Surface heater for a toaster|
|US3751633 *||Oct 8, 1971||Aug 7, 1973||Green W||Plug-in chamber furnace|
|US3767895 *||Dec 1, 1971||Oct 23, 1973||Infra Red Circuits & Controls||Portable electric radiant space heating panel|
|US3806701 *||Nov 3, 1972||Apr 23, 1974||Rival Manufacturing Co||Electric cooking utensil having a removable vessel|
|US3816704 *||Mar 20, 1972||Jun 11, 1974||Gen Electric||Surface heating apparatus|
|US3839620 *||Oct 13, 1972||Oct 1, 1974||Seibel R||Condensation free mirror|
|US3869596 *||Sep 28, 1973||Mar 4, 1975||Safeway Products Inc||Cookware heater|
|US3883719 *||May 10, 1974||May 13, 1975||Gen Electric||Glass-ceramic cooktop with film heaters|
|US3887788 *||Jun 26, 1973||Jun 3, 1975||Seibel & Seibel Enterprises||Condensation free mirror|
|US4063068 *||Aug 12, 1976||Dec 13, 1977||Minnesota Mining And Manufacturing Company||Food heating and cooking receptacle|
|US4250396 *||Sep 4, 1979||Feb 10, 1981||Walter Leuca||Heated drafting board|
|US4294009 *||Jun 28, 1979||Oct 13, 1981||Le Material Telephonique||Method of manufacturing a hybrid integrated circuit|
|US4542268 *||Jan 28, 1980||Sep 17, 1985||Litton Systems, Inc.||Browning heater for a microwave oven|
|US4602238 *||Jan 20, 1984||Jul 22, 1986||Vitronics Corporation||Infrared panel emitter and method of producing the same|
|US4677801 *||Sep 11, 1985||Jul 7, 1987||Martin Bard||Wall, ceiling and/or floor formation and a method for producing it|
|US4682009 *||Jun 11, 1985||Jul 21, 1987||Thermotechnik G. Bauknecht Gmbh||Wall mounted combined radiactive-convective electric space heater|
|US4833301 *||Mar 25, 1987||May 23, 1989||Vitronics Corporation||Multi-zone thermal process system utilizing nonfocused infrared panel emitters|
|US4843218 *||Sep 8, 1988||Jun 27, 1989||Bosch-Siemens Hausgerate Gmbh||Heating element for thermal heating devices, especially cooking stations|
|US5026970 *||Jul 27, 1989||Jun 25, 1991||Emaco Ltd.||Cooking appliances|
|US5502293 *||May 25, 1993||Mar 26, 1996||Terumo Kabushiki Kaisha||Heater element for a tube connecting device|
|US6018288 *||May 14, 1998||Jan 25, 2000||Indak Manufacturing Corp.||Flat resistors for automotive blower motor speed control or other service|
|US7764873 *||Apr 8, 2004||Jul 27, 2010||Stylianos Panaghe||Radiant electricating element with printed heating and ceramic tracks|
|US8447176 *||Oct 8, 2009||May 21, 2013||Mark J. McCourt||Dual chimney flat panel convection air space heater|
|US20050002659 *||Apr 8, 2004||Jan 6, 2005||Stylianos Panaghe||Radiant electric heating element|
|US20050167414 *||Jan 30, 2004||Aug 4, 2005||Po-Chun Kuo||Cooking device with a thick film resistive element heater|
|US20110085783 *||Oct 8, 2009||Apr 14, 2011||Mccourt Mark J||Dual chimney flat panel convection air space heater|
|EP0229351A1 *||Dec 17, 1986||Jul 22, 1987||Buchtal Gesellschaft mit beschränkter Haftung||Flat ceramic element|
|EP0280150A1 *||Feb 15, 1988||Aug 31, 1988||Buchtal Gesellschaft mit beschränkter Haftung||Space heating element consisting of a ceramic body provided with an electrically resistant layer, especially in the form of a ceramic plate|
|EP0675670A2 *||Mar 27, 1995||Oct 4, 1995||Morillo Casals, Pilar||Radiant panel with improved printed circuit|
|WO1985003402A1 *||Jan 10, 1985||Aug 1, 1985||Vitronics Corp||Infrared panel emitter and method of producing the same|
|U.S. Classification||216/16, 392/439, 427/123, 427/259, 29/611, 219/543, 427/96.2, 427/270, 338/254, 338/308|
|International Classification||H05B3/26, H05B3/22|