US3122627A - Ovens or stoves - Google Patents

Description

H. JERU ovENs 0R sTovEs Feb. 25, 1964 2 Sheets-Smeltl 1 Filed Dec. 20, 1962 Feb. 25, 1964 H. JERU 3,122,627

OVENS OR STOVES Filed Dec. 2o, 1962 2 sheets-sheet 2 ef v mumumuu i .c f I `-qlo 111/' f1 2 l l I United States Patent O 3,122,627 OVENS OR STOVES Henri Jru, 4 Ave. du Chevalier Borda, `Le Trait, France Filed Dec. 20, 1962, Ser. No. 246,141 Claims priority, application France Dec. 28, 1961 2 Claims. (Cl. 21935) The present invention relates to improvements in ovens or stoves of the kind in which the side walls or the crown, and when so desired the sole or hearth, are fitted with thin metallic strips which form at least part of the said s1de walls and of the said crown or hearth, the said metallic strips being adapted to receive an electric heating current. These strips may or may not serve as supports for a heatinsulating lining.

Furnaces of this kind, utilized as electric furnaces heated by resistance strips, have a great many advantages: low heat inertia, resulting in a rapid run-up to operating temperature, uniform temperature distribution, which may be still further improved by providing a circulation of a air or some other gas in closed circuit in the interior of the furnace, and low cost of construction and operation.

An object of the present invention is to extend the application of the aforementioned type of furnace construction furnaces employing other sources of thermal energy and especially all liquid, solid or gaseous fuels, or nuclear energy, in combination, when so required, with they electrical energy generated in the metallic strips. This combination of two methods of heatngcan be carried out either successively or simultaneously. In particular, the strips may be used as electric resistance heaters at night rduring the off-peak hours, and solely as metal radiation and temperature-equalizing surfaces heated by a uid in contact with the walls thereof, during the day.

For this purpose, it is only necessary to heat a mass of air or other gas, inside or outside the furnace, by any particular form of energy, such as electrical, thermal or atomic, and to permit the heated air to come into contact with the initially-provided strips in closed circuit, the strips acting as electric resistance heaters. y

The hot fluid may be introduced into the furnace parallel to the surface of the radiant strips through one or more ducts parallel to the strips. It may also pass in through part or all the spaces which separate the heating strips. The extraction of the hot air or gases for the purpose of .re-cycling is effected in a similar manner, by means of a fan included in the circuit. Burners or heat exchangers are also included in the same circuit.

The invention will now be further described by means of several embodiments, given by way of example only,

reference being made to the accompanying drawings, in which: s y

FlG; lis a view in transverse section of a furnace according to the invention;

FIG. 2 is a view in transverse section of an alternative form of furnace according to the invention;

FIG. '3 is a view in longitudinal section of the furnace shown in FIG. 2;

ll'FIG. 4 is a view in transverse section of a further alternative form of furnace; f y

FIG. 5 is a View to a larger scale of a detail of FIG. 4.

Referring to FIG. l, a furnace is constituted by metallic strips 1, forming the crown and the side walls of the furnace, these metallic strips being rcapable of serving as electrical heating resistances. They are suspended by tierods 6 to a framework 7, when so required, through the intermediary of springs 8 intended to compensate for thermal expansion. y

A closed circulation of air is effected in the interior of the furnace, this air being delivered from an upper ventilation duct 17, and then flowing along the inner surface before being sucked into a lower suction duct 18 s0 lCe as to pass through a blower 19 which `delivers it into a duct 20 returning towards the duct 17. The air in the duct 20 is heated in an exchanger or a combustion chamber 21. ln FIGS. 2 and 3, the air circulation is effected by means of a transverse supply duct 24 located in the center of the furnace with a return duct at the lower part of the furnace, at 25. There is also provided on the delivery conduit 26, an exchanger or combustion chamber 27.

In FIGS. 4 and 5, the furnace is constituted by metallic strips 31 suspended from a framework by tie-rods 32 with springs 33 in the upper portion, and by brackets 34 in the side portions, the tie-rods and brackets acting through the intermediary of insulating rollers which permit the sliding movement of the strips 31, subjected at their free extremities to the action of tension springs 35. The furnace is insulated by a layer 36 of glass wool or refractory brick wool, contained between two sheets 37 andk 38.

The connections 31a and 31b at the lower portion of the furnace provide the heat necessary for heating, by convection and/ or radiation, the lower part of the articles in course of treatment.

The air circulation is effected by an upper duct 39 eX- tending along the furnace with side delivery holes 40 and 41, while the air is drawn into a lower duct 42 and delivered to a blower 43 and thence into a delivery duct 44 which terminates at the yduct 39. In this embodiment, the

The inner support of the insulation 36 is advantageously constituted by thin plates 37, reflecting or otherwise, which face the heating strips 31 and thus increase the insulation. The outer portion of this insulation may also be reflecting at 38, together with the outer part of the heating strips 31. On the other hand, the internal portion of the heating strips 31 is preferably black in color.

Depending on thetemperature to which they are subjected, these sheets, if they are reecting, may be of aluminum or of stainless steel of very small thickness, corrugated or ribber, as the case may be. They also fulfill the purpose of preventing small bits offglass wool or refractory brick wool from being carried away into the furnace by the circulation of air and` being deposited on the articles. y

They are thus of special advantage in painting or enameling ovens.

The insulating panels 36 to 38 have a thickness greater than the webs of the framework sections, so that the latter are covered with insulation at their upper portions, fluid-tightness being ensured for example by means of stuck strips 51.

What I claim is:

l. A furnace which is heated by electricity or by hoty gases or simultaneously by electricity and by hot gases, said furnace comprising a framework, a heat insulating casing affixed to said framework, a workingchamber supported by said framework` and spaced apart from said heat insulating casing, said working chamber comprising electrically conducting fiexible strips which form electrical heating resistances, said strips being disposed transversely to the longitudinal axis of the furnace and spaced apart longitudinally, means including tie-rods and springs for mounting said strips upon said framework, a source" of electric current, means for connecting said strips forming electrical heating resistances in series across' said source, `conduit means arranged at the upper portion of the furnace for bringing in the hot gases and delivering the latter into the space between the working chamber and the 'Patented Feb. 25, 1964 heat insulating casing, a duct for the outgoing hot gases arranged at the lower portion of the furnace, and means for creating a circulation of the hot gases through said conduit means, said Working chamber, and said duct.

2. A furnace as claimed 'in claim 1, in which Said tierods are disposed perpendicularly to said strips, electrically insulating rollers couple said tie-rods to said strips, and said springs connect said tie-rods to said framework.

269,760 Weston Dec. 26, 1882 Edwards Feb. 5, 1895 Haagn June 5, 1906 Youmans June 17, 1913 Asch May 6, 1930 Potensa Oct. 4, 1932 Heyroth et al Apr. 10, 1934 Trent Apr. 4, 1939 Ayers May 2, 1939 Duffy et al July 21, 1959 Naylor Oct. 13, 1959

Claims (1)

1. A FURNACE WHICH IS HEATED BY ELECTRICITY OR BY HOT GASES OR SIMULTANEOUSLY BY ELECTRICITY AND BY HOT GASES, SAID FURNACE COMPRISING A FRAMEWORK, A HEAT INSULATING CASING AFFIXED TO SAID FRAMEWORK, A WORKING CHAMBER SUPPORTED BY SAID FRAMEWORK AND SPACED APART FROM SAID HEAT INSULATING CASING, SAID WORKING CHAMBER COMPRISING ELECTRICALLY CONDUCTING FLEXIBLE STRIPS WHICH FORM ELECTRICAL HEATING RESISTANCES, SAID STRIPS BEING DISPOSED TRANSVERSELY TO THE LONGITUDINAL AXIS OF THE FURNACE AND SPACED APART LONGITUDINALLY, MEANS INCLUDING TIE-RODS AND SPRINGS FOR MOUNTING SAID STRIPS UPON SAID FRAMEWORK, A SOURCE OF ELECTRIC CURRENT, MEANS FOR CONNECTING SAID STRIPS FORMING ELECTRICAL HEATING RESISTANCES IN SERIES ACROSS SAID SOURCE, CONDUIT MEANS ARRANGED AT THE UPPER PORTION OF THE FURNACE FOR BRINGING IN THE HOT GASES AND DELIVERING THE LATTER INTO THE SPACE BETWEEN THE WORKING CHAMBER AND THE HEAT INSULATING CASING, A DUCT FOR THE OUTGOING HOT GASES AR-

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