US2041486A - Electric furnace - Google Patents

Description

May 19, 1936. p RICHALET 2,041,486

ELECTRIC FURNACE Filed Ju ne29, 1934 2 Sheets-Sheet l [22Ve22 for:

May 19, 1936. P. RICHALET ELECTRIC FURNACE 2 Sheets-sheaf. 2

Filed June 29, 1934 Patented. May 19, 193

UNITED TATE TENT Application June 29, 1934, Serial No. 733,110 In Belgium June 30, 1933 y 6 Claims.

The present invention relates to electric furnaces and more especially to electric furnaces for melting and treating materials with a view to obtaining glass or similar products. a

The object of the present invention is to provide a furnace of the type above referred to with which the thermic treatment in a quicker, more precise and more economical manner, while giving-products, and more especially glass products, which are more homogeneous and more regular in their structure.

The essential feature of the present invention consists in providing furnaces of the type above referred to with heating elements which are movable and immersed, at least partly, in thematerials to be treated, so that these elements are capable of ensuring not only heating to the de-- sired temperature but also the stirring of said materials.

Other features of the present invention will result from the following detailed description thereof.

Preferred embodiments of the present invention will be hereinafter described, with reference to the accompanying drawings, given merely by way of example, and in which:

Fig. 1 is a vertical sectional view of an electric furnace according to a first embodiment of the present invention;

Fig. 2 is a similar view of an electric furnace made according to another embodiment of the invention;

Fig. 3 shows on an enlarged scale a detail of the structure of Fig. 2;

Fig. 4 is a diagrammatic elevational View, partly in section, of a third embodiment of the electric furnace according to the present invention.

As shown in the drawings, the furnace-or crucible proper a is made in any suitable manner, as far as its size and its shape are concerned and the walls of this furnace are suitably heat insulated. In these walls I provide one or several openings b for introducing the raw materials into the furnace and one or several openings 12 for withdrawing melted glass. The furnace may consist of a. single chamber or of several chambers separated by a partition 0 (Fig. 1-) provided with a passage 0 for connecting the difierent chambers together. For instance, in the embodiment of Fig. l, chamber may serve to melting the matters and chamber c to the refining of the glass.

Instead of heating the mass by means of electric resistances utilized either alone or in combination with other heating means, I make use of heating elements 11 immersed either partly or fully in the mass of matters to be treated.

These heating elements consist of electric resistances, either single or multiple, 6 which are either bare or encased, either Wholly or partly, in 5 a mass of a refractory material 1 in such manner as to develop and transmit heat in any suitable manner.

Each furnace or each compartment of the furnace is provided with one or more heating elements suitably distributed therein. These heating elements are disposed either vertically, as in the embodiment of Fig. 1, or horizontally, as in the embodiment of Fig. 2, or generally speaking in any suitable position, the respective resistances of the various elements being either similar or different.

By disposing the heating elements in the midst of the mass to be treated, I can utilize the whole of the calories to be emitted, which corresponds to the maximum calorific efiiciency with a View to obtaining a reduction of the components of glass, their vitrification and the refining of the melted glass.

- The heating elements aremovable in the mass, with any desired motion, for instance with a rotary, oscillating, rectilinear, reciprocating, or other movement, in order to obtain not only the heating of the mass but its stirring, which makes it possible to do away with supplementary organs, both cumbersome and expensive, for performing this function. In order to improve this stirring effect, I may provide, on the heating elements, auxiliary organs, such as ribs, projections, blades or the like, which complete the stirring action resulting from the rotary movement of the heating elements.

In the embodiment shown in the drawings it has been assumed, by Way of example, that the heating elements are given a rotary movement 40 about their longitudinal axis, either in the same direction or in opposite directions. As shown by way of example by Fig. 1, these movements are imparted to the heating elements (Z through gears 91 driven by a suitable motor. for instance an electrical motor provided with a suitable speed reducing gear. Furthermore, each element carries a helical rib h wound in accordance with the direction of rotation. Close to 50 the place where the spires of this helical rib emerge from the mass that is treated, they stop and are prolonged by some spires of a helical rib h wound in the opposite directions so as to prevent the materials from being conveyed as far as the end of the heating element as by a kind of Archimedean screw.

When the heating elements are disposed in a vertical position and are Supported merely by the upper face (or even the under face of the furnace) in such manner that the free end of each of these elements is not in contact with the opposite wall of the furnace, the resistance, made of graphite, metal or any suitable matter, is advantageously given the shape of a Li (Figs. 1 and 4). The free ends of the lateral branches then serve as input and output terminals and are then connected, through a suitable rotary distributor i, with the source of energy.

when the heating elements rest on two opposite walls of the furnace, and especially when they are disposed horizontally, as in the embodiment of Figs. 2 and 3, the resistance may be rectilinear, current flowing in at one end and out at the other end of each resistance.

Special precautions must be taken for the movable resistances, and more particularly when the heating elements are disposed horizontally in the furnace below the free level of the mass, so as to ensure tightness and lubrication at the places where the elements pass through the walls of the furnace. In Fig. 3, I have shown an example of an arrangement giving satisfactory results to this respect. Each end of the heating element is engaged in a sleeve is made of an insulating material, which constitutes the journal of the rotary heating element. The outer lateral face of this sleeve is is provided with circular ribs on which are engaged annular pieces 2 made of a lubricating material adapted to withstand high temperatures, such as plumbago. Between these pieces 1, I insert, for instance by moulding, crushed graphite or an analogous material 112, which also resists the temperatures that are considered and which fills, in a fluidtight manner, all the cavities that may exist between sleeve is and pieces I, on the one hand and between the different pieces I themselves, on the other hand. Of course this is not the only possible means for insuring tightnets and lubrication and it should be well understood that I do not limit myself to this specific embodiment.

In the preceding description it has been assumed that the furnace proper is itself stationary. But the arrangement above described can be utilized with a furnace, crucible, or other container, that is movable, for instance rotatable, this container being thus mounted either in a stationary position or removable or again of the tilting type (Fig.4). Furthermore, the furnace may include heating means that are either permanent or temporary, said means being not necessarily electric means and being not necessarilylodged in the walls of the furnace.

To each of the heating elements, or to only certain of them I may add thermostatic or py ometric organs, and especially thermostatic couples p mounted for instance in said elements and through which it is possible to ascertain the degree of heating of the mass, with a view to adjusting .the temperature.

In Fig. 4 I have shown by way of example a furnace a. heated according to the invention and which is more especially adapted to the pouring of melted glass or the like. This furnace is mounted through trunnions n in bearings provided in a suitable support 0. In this case, the heating element or elements (.1, their support, their electric distributor, and also their control organs mayfbe so arranged that these heating elements can be moved upwardly out from the casting ladle a. The support 0 might also be arranged in such manner as to be movable downwardly a sufficient distance for disengaging the heating elements from the casting ladle, said heating elements remaining at a fixed level.

In either of these cases it is possible, after disengaging the heating elements, to tilt the casting ladle a so that the melted glass is poured in the usual manner.

I might also make the heating element in such manner that it is a part of a mould, the remainder of which consists of the crucible or furnace, and the faces of which that cooperate with said crucible are so shaped that (a relative movement being provided between these organs) after melting of the raw material, or of the composition of matter introduced into the crucible, there is obtained a piece, for instance of moulded or pressed glass, or again of metal, having the desired shape, which may be the definitive shape.

As already stated, the disposition of the heat ing elements in the mass to be treated permits of obtaining the maximum calorific efficiency, because the whole or the heat, emitted and transmitted by conductibility, radiation, or convection, is transmitted directly to said mass without externallosses having to be taken into account.

Furthermore this arrangement makes it possible to activate the melting of the components, while improving the quality and reducing the cost of the finished product by dispensing with the use of some active components that are usually employed for obtaining the chemical stirring of the mixture in the course of melting.

It is possible to stop, at any given time, the vitrification of the glass components, before complete melting, so as to obtain in this way, with great accuracy, an intermediate product that is of interest for particular applications.

The obtainment of high and stable temperatures permits of obtaining easily and with great regularity the melting of the components of a glass having a very low coeflicient of dilatation. which, with known methods and furnaces, was practically impossible to obtain.

Furthermore it is possible to avoid devitriiication phenomenons, which are often observed in the course of the usual melting operations. Up to now these drawbacks could only be attenuated through chemical means.

By disposing the heating elements in the mass, which renders the whole practically independent of any external heating device, it is possible to obtain melting in an autoclave, either stationary or movable, with compression, or self-compression, of the materials that are treated. This greatly reduces ignition loss due to melting and also reduces to a considerable degree the time necessary for the melting of the components and therefore the amount of energy that is consumed. In this case the melting operation can take place in a neutral, reducing, or oxidizing medium by introducing into the autoclave a suitable product for instance in the solid or gaseous form.

The electric furnace above described can be used for the treatment of all matters, either simple or composite, vaporizable, reducible and fusible, and especially glass compounds, in thermic plants of any known type, without it being necessary to insist on the detail of the various cases that may occur. Among the important and possible applications of this invention, attention should be called to continuous furnaces for feeding automatic machines for the 75 manufacture of glass objects, such as bottles, the melted matter being withdrawn from the furnace mechanically by means of feeders, through pneumatic means, etc.

While I have, in the preceding description, disclosed what I deem to be practical and eflicient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

1. An electric furnace for treating or melting glass, which comprises in combination, a container for the glass mass to be treated, at least one cylindrical heating element rotatable during heating in said container about its own axis and so positioned as to be at least partly immersed in said mass, means for rotating said heating element, means carried by said heating element for stirring the mass, and electric means in said element for generating heat therein.

2. An electric furnace for treating or melting glass, which comprises in combination, a container for the glass mass to be treated, at least one cylindrical heating element rotatable during heating in said container about its own axis and so positioned as to be at least partly immersed in said mass, means for rotating said heating element, means carried by said heating element for stirring the mass, at least one heating resistance in the interior of said heating element.

3. An electric furnace for treating or melting glass, which comprises in combination, a container for the glass mass to be treated, at least one cylindrical heating element rotatable during heating in said container about its own axis and so positioned as to be at least partly immersed in said mass, means for rotating said heating element about its axis, a helical rib carried by the periphery of said heating element for causing the surrounding matter to move along it, means for preventing said matter to move past a certain point of said heating element, and electric means in said element for generating heat therein.

4. An electric furnace according to claim 3 in which the means for preventing said matter to move past a certain point of said heating element consist of a helical rib carried by said element and wound in opposite relation to the first mentioned helical rib.

5. An electric furnace for treating or melting glass, which comprises in combination, a container for the glass mass to be treated, at least one cylindrical heating element rotatable during heating in said container about its own axis and so positioned as to be at least partly immersed in said mass, means for rotating said heating element, means carried by said heating element for stirring the mass, means in said element for indicating the temperature thereof, and electric means in said element for generating heat therein.

6. An electric furnace according to claim 1 in which the heating element is horizontally disposed below the upper surface of the mass and is joumalled in the lateral walls of the container, further comprising means for ensuring tightness and lubrication of the bearings.

PAUL RICHALET.

CERTIFICATE OF CORRECTIOH.

Patent No. 2,041,486. May 19, 1936.

PAUL RICHALET.

It is hereby certified that error appears in the above numbered patent requiring correcticn as follows: In the drawings strike out Sheet 2- containing Figure 4; and the heading to present Sheet 1, strike out "2 Sheets- Sheet 1"; and that the said Letters Patent shquld be read with these corrections therein that the same may conform to the record of the case in the Patent Office. V

Signed and sealed this 30th day June, A. D. 1956.

Henry Van Arsdale Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 2,041,486. May 19, 1936.

PAUL RICHALET.

It is hereby certified that error appears in the above numbered patent In the drawings strike out Sheet 2 conrequiring correction as follows: taining Figure 4; and in the heading to present Sheet 1 strike out "2 Sheets- Sheet 1"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 30th day June, A. D. 1956.

Henry Van Arsdale Acting Commissioner of Patents.

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