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Publication numberUS2644881 A
Publication typeGrant
Publication dateJul 7, 1953
Filing dateDec 15, 1949
Priority dateDec 20, 1948
Publication numberUS 2644881 A, US 2644881A, US-A-2644881, US2644881 A, US2644881A
InventorsSchorg Carl Christian
Original AssigneeSchorg Carl Christian
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Inductively heated electrical contact furnace with preheater
US 2644881 A
Abstract  available in
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Description  (OCR text may contain errors)

July 7, 1953 c. c. sei-icm@ INDUCTIVELY HEAT ED ELECTRICAL CON FURNCE WITH PREHEATER Filed Dec. 1949 Patented July 7, 1953 INDUCTIVELY HEATED ELECTRICAL CON- IACT FURNACE WITH PREHEATER Carl Christian Schrg, Frankfurt am Main Hcchst, Germany Application December 15, 1949, Serial No. 133,205

In contact furnaces having annnular shaped reaction chambers for carrying out the chemical reactions, it is frequently the case that useful space is lost by taking in at too low a temperature cf the gases which are to carry out the reaction in the furnace, and which first must be raised to the temperature at which the reaction takes place.

Attempts have been made to avoid this difficulty by conducting the gases through a separately arranged pre-heater, wherein same are raised to approximately the reaction temperature, before they enter the reaction furnace itself. This method, it is true, accomplished the desired results, in production operation, but it unavoidably resulted in the disadvantages that the furnace and pre-heater structure became more complicated, required more space, and a greater capital expenditure. It has also been attempted to avoid these disadvantages by providing the heated furnace with a short circuited secondary winding consisting of a coiled pipe, wherein the gases were raised to approximately the reaction temperature by inductive heating before they entered the reaction chamber of the furnace. In this way, it was perhaps the case that a simple and somewhat inexpensive structure was provided. The disadvantage still existed, however, that there was a fixed ratio of heat transfer capacity between the primary and secondary components, that is, between the furnace and the pre-heater, whereas in actual practice this ratio is required to be variable within wide limits, a result that cannot be attained with the simple structure according to this arrangement.

According to the present invention the desired result may be attained by constructing in the inner space of the annular chamber of a reaction furnace an electrically energized preheater, which is preferably heated according to the induction heating principle.

The arrangement according to the present invention is shown in vertical section in Figure l; and,

Figure 2 is a cross-sectional view of the structure shown in Figure 1.

Referring now to the drawing in detail, the reference character A represents the annular reaction chamber of the contact furnace, wherein the reactions take place. The exterior wall B of the furnace is inductively heated by the heat resistant windings C, which are energized by the respective phases of a polyphase alternating current power system. A central conduit E In Germany December 20, 1948 1 claim. (c1. 21e-47) is positioned in the inner part ofthe annular space, which latter is bounded on its outer periphery bythe wall D. Heat resistant coils F are positioned intermediate the central conduit E and the wall D and are respectively connected to the different phases of a polyphase electrical power system to effect heating by the inductive heating principle. The space between the wall D and outer surface of the conduit E is determined so that the exciting coils F exactly t there. As thus positioned, they are equally effective in heating the wall D. The electrical energy converted into heat must be sufficient for equalizing the heat differential between the wall D and conduit E.

The interior G of the central conduit E constitutes the pre-heater chamber and this is normally lled with granular material. The gases are admitted to the pre-heater chamber G through a central tube H, which is connected to the central conduit E, and are raised in the preheater chamber to the reaction temperature or approximately thereto. They leave the preheater chamber G under the cover J and pass to the annular chamber A, where the reaction takes place. From the annular chamber A they are conducted from the furnace by pipes K.

For the purpose of obtaining the desired relative variations in the temperatures of the preheater chamber G and the annular reaction chamber A, it is desirable that the coils F for the pre-heater chamber and the coils C for the reaction chamber be separately energized.

The operation of the combined Contact furnace and pre-heater according to the present invention may be varied according to the load demands within wide limits. When carrying out exothermic processes, the superfluous heat, which is not used for carrying out the reaction is used for pre-heating; when carrying out endothermic processes, the heating from the inductor coils on both sides of the annular reaction chamber effects a very uniform reaction process. The heat resistant exciting windings, which effect the inductive heating, are put in and around the furnace in the usual manner. Automatic controllers (not shown) may be provided for maintaining the thermal equilibrium.

If the chemical reaction process to be carried out should so require, the pre-heater chamber and the annular reaction chamber may be interpositioned, the latter being placed on the outside of the furnace and the former axially thereof, without departing from the principle of the invention. Also, the reaction process to be carried out may be the inverse of that described, that is, the gases may be directed from the top into the pre-heater chamber and from below into the reaction chamber.

The electrical heating could also be accomplshed by resistance coils. Since, however, there is always present the danger of explosion in carrying 'out most production operations heating by the inductive effect is the preferred form.

Having now fully described my invention, what I claim as new and useful and desire to secure by Letters Patent of the United States:

In an electrical heating furnace for carrying out high temperature exothermic and endothermic reactions, a central pre-heating chamber, a central conduit connected to said pre-heating chamber for conducting gases thereto, a 'plurality of inductor coils adapted to be connected, respectively, to the various phases of a polyphase power system closely surrounding said pre- Lheating chamber in aligned .relationship,ran annular reaction chamber surrounding said preheating chamber closely positioned with respect to the coils therearound, a cover over the central pre-heating chamber and the annular reaction chamber for directing the heated gases from the former reversely through the latter, and a plurality of inductor coils adapted to be connected, respectively, to the various phases of a polyphase power system closely surrounding said an- .nular reaction chamber in aligned relationship.


References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,078,619 Greene Nov. 18, 1913 1,356,818 Hadaway, Jr. Oct. 26, 1920 .1,513,087 Buhl et al. Oct. 28, 1924 1,986,348 Lacy et al. Jan. l, 1935 2,517,098 Dreyfus Aug. 1, 1950

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1078619 *Jan 23, 1911Nov 18, 1913Albert E GreeneElectric furnace.
US1356818 *Jul 11, 1917Oct 26, 1920Hadaway Jr William SHeating apparatus
US1513087 *Mar 29, 1922Oct 28, 1924Nat Electric Water Heater CompElectric heater
US1986348 *Jun 13, 1931Jan 1, 1935Du PontApparatus for effecting gas reactions
US2517098 *Nov 12, 1948Aug 1, 1950Asea AbInduction furnace
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2805309 *Sep 20, 1955Sep 3, 1957Asea AbInduction heating
US3277265 *Jan 20, 1964Oct 4, 1966Traitements Electrolytiques EtPlasma heating systems
US3310426 *Oct 2, 1963Mar 21, 1967Siemens AgMethod and apparatus for producing semiconductor material
US3445616 *Dec 6, 1966May 20, 1969Corning Glass WorksElectric flame generator
US4217475 *Aug 25, 1978Aug 12, 1980Hagerty Research & Development Co., Inc.Apparatus for transferring heat to fluids
US4431890 *Dec 22, 1980Feb 14, 1984Ramer James LInduction heated steam flash plug
US4471191 *Sep 22, 1982Sep 11, 1984Asea AbDevice for heating fluent material flowing past short-circuited heating elements within induction coils
US4608471 *Mar 5, 1985Aug 26, 1986Allied Tube & Conduit CorporationImpeder with aggregate ferromagnetic core
US4855552 *Jul 1, 1988Aug 8, 1989Hydro-QuebecFluid heating device incorporating transformer secondary winding having a single electrical turn and cooling means optimized for heat transfer
US4869734 *Dec 27, 1988Sep 26, 1989Tri-Dim Filter CorporationAdsorption of solvents on carbon
US6046442 *Sep 17, 1996Apr 4, 2000Kabushiki Kaisha Seta GikenTemperature controller of electromagnetic induction heater and its start system
EP0193843A1 *Feb 25, 1986Sep 10, 1986AlsthomThermo-inductive generator for the production of a warm fluid
EP0852452A1 *Sep 17, 1996Jul 8, 1998Kabushiki Kaisha Seta GikenTemperature controller of electromagnetic induction heater and its start system
U.S. Classification219/630, 219/669, 392/468, 373/144
International ClassificationH05B6/02
Cooperative ClassificationH05B6/108
European ClassificationH05B6/10S6