US1496372A - Electric fire pot - Google Patents

Description

June 3 1924- W. S. HADAWAY. JR

ELECTRIC FIRE POT Filed March 24, 1922 A TTORNEY.

Patented June 3, 1924.

WHILIAI S. HADA'WAY', JR, NEW ROCHELLE, NEW YORK.

ntnc'rnrc rum ror.

Application fled larch 24, 1922. Serial Io. 548,387.

To all whom it may concern:

Be it known that I, WILLIAM S. HADAWAY Jr., acitizen of the United States, anda resident of New Rochelle. county of Westchester, and State of New York, have invented certain new and useful Improvements in Electric Fire Pots, of which the followin is a specification.

%his invention relates to improvements in W electric fire pots and more particularly to apparatus such as is used for the melting or heat treatment of metals, or for other purposes requiring very high temperatures. The invention has for its main object the improvement of means for the generation of high temperatures and the provision of apparatus of higher efficiency that shall be applicable to a variety of purposes For example, the heat applicator of my inven- 29 tion may be used in connection with a melting crucible for the refining or treatment of metal; in which case its heat is directed to the work by radiation and suitable reflection. Or it may be employed as an immersion type of heater; in which case its heat is applied by conduction. Again. it may be used as a central generator or furnace in a system of heat distribution; in which case the heat is carried to the utilities 30 by convection. The invention serves to intensify combustion in a chamber and effectually to control the rate of combustion.

Another object relates to means for employing as one active agent a relatively high cost medium in combination with a relatively low cost medium whereby the ciliciency of the high cost medium in producing heat is greatly increased resulting in a reduction of the proportional amount of the high cost medium.

Another object relates to the provision of electrodes of im roved construction and the employment 0? a fuel in proximity thereto, whereby high temperatures relative to the theoretical combustion temperature of the fuel may be obtained and utilized. According to this feature, a material such as magnesia, having predetermined characteristics at high temperatures, is employed in the electrodes, whereby the formation of carbides in combination with the carbon contained in the fuel, which has occurred with electrodes of dprior construction, is effectually prevente Another feature relates to the provision of an improved electric furnace em loying a gas for initiating combustion an maintaining the temperature of a burning fuel at or near its temperature of chemical combination, whereby an incandescent resistor of greatly increased length and temperature 15 produced.

nother feature relates to a heat applicator in which an electric fire pot is provided with active electric members or electrodes which are non-combustible whereby tllieficgntrol and regulation of heat are simp 1 e Still another feature relates to interchangeability of parts. whereby the heat applicator may be readily and conveniently replaced in the container in which it is employed.

Other objects will appear from the following description taken in connection with the accompanying drawing, in which,

Fig. 1 shows a sectional elevation of a heat applicator of my invention. in position for heating the contents of a melting pot.

Fig. 2 shows an enlarged sectional view of a portion of the apparatus.

Fig. 3 shows a section taken on the line 3-3 of Fig. 2.

Fig. 4.- is a sectional view of a modified form of the invention shown in Fig. 3.

' Like characters of reference refer to like parts in the several figures of the drawing.

Referrin to the drawing. there is shown an illustrative embodiment of the invention, comprising a cylinder 15 of refractory material, having its lower end closed and preferably rounded off to facilitate immersion thereof into viscous liquids. .The cylinder may be ridged or corrugated in order to increase its active surface. The open up er end of the cylinder is closed by a detachable seal comprising a cover plate 17 resting on an internal shoulder in the cylinder 15 and preferably secured thereto in any suitable manner. The plate 17 is made of a suitable refractory material and is surmounted by a second plate 18 made of a material which is an insulator of electricity and capable of withstanding a high degree of heat.

A urality of electrodes such as 20, 21 extend through slots in the plates 17, 18 the supports therefor being secured to the insulatin plate 18, in any desired manner. Eac of these supports (Fig. 2) comprises a yoke or bridge'22 for pivotally supporting upon trunnion bearings the respective electrode and its carriage 23 (Fig. 3). Thus the electrodes may be rocked or tilted. Each of the yokes 22 has an extension 24 with an upri ht toothed segment 25, and the corresponding electrode carriage 23 has an arm 26 movable in proximity to the segment 25. The free end of each arm 26 is shaped in the form of a handle and suitable latching means 27 may be provided for maintaining the electrode in a given position when desired. It is understood, how.-

- ever, that any suitable form of moving or maintaining means, automatic, manual or semi-automatic, may be employed for these pu ses.

e electrode supports and carriage are preferably made of nickel chromium or other suitable material.

The electrodes 20, 21' are made of a fulgurite such as oxide of magnesia, which is a conductor of electricity only when hot. They are made hollow in the form of tubes, the upper extremity of each being provided with a suitable binding post 30. Each elec trode is mounted or clamped on the carriage 23 in any suitable manner and a transverse passage .31 leads through the wall of the electrode, one flange of the carriage member 23 and through a stufiing box 32, connecting to a supply 33 for supplying a suitable gas or Vapor to the electrode. The binding posts each may comprise a split collar 30 of electrically conducting material fitted over the upper end of the respective electrode, and fastened by means of a suitable set screw. Leading from the electrodes is a corresponding plurality of conductors connected to a source of current 34:. The source current and as shown a single phase alternating current is supplied; it is understood,

however, that two or three phase current may be employed, the number of conductors and electrodes being then increased to four and three each respectively.

The supply 33 isconnected to a main passage 35 leading to one of the electrode supports for supplying active medium thereto. A by-pass therefrom (see Fig. 1) leads to one part of a valve 36. A second part of the valve is connected by means of a passage 37 to another of the electrode supports, and serves to supply or to withdraw active medium therefrom depending upon the position of the valve 36. A third part of the valve 36 is connected by means of a passage 38 to the source 33.

The passage 38 may be extended'to utilities instead of to the source 33, and theproducts of combustion and unconsumed vapors may thereby be employed to actuate such utilities. The utilities may take any desired form, such as that of a hot plate of conventional design.

In the interior of the receptacle formed by the cylinder 15 is placed a suitable uantity of carbonaceous fuel 40, preferab y in granular form.

The applicator comprising the cylinder 15, the plates 17, 18 and associated parts, is shown in position in connection with a melting pot 50. In the example illustrated a quantity of metal 51 is placed in the pot to be melted by heat. The a plicator may be similarly inserted into any ody of liquid for quick heating thereof. Furthermore, the applicator may be employed for heating a room. By providing a path of escape from the upper portion of the interior of the cylinder 15 to suitable conducting passages, the products of combustion and unconsumed vapors may be carried to utilities spaced from the applicator. Such use does not prevent the use of the applicator for the direct application of heat as well.

In operation, the source of current 34 is started and its circuit closed to cause current to flow through the circuit of the electrodes 20 and 21; the circuit also includes that portion of the carbonaceous fuel between the electrodes. On account of the high resistance of the electrodes when cold little or no current flows. The valve 36 is set in the position shown in Fig. 1. A supply of hot gas or vapor such as superheated steam, for example, is now supplied through.

the passages 31 and the interior passage of each of the electrodes to the lower extremities thereof. The heat of the vapor isimparted to the electrodes whose resistance is reduced thereby, and current flows. The temperature of the incoming gases may be and generally is sufliciently high to initiate combustion of the fuel surrounding the ends of the electrodes. I

The heat obtained from the burning fuel also lessens the resistance of the electrodes and as the temperature rises a gaseous path from electrode to electrode results which has the characteristics of a stable, enclosed arc.

The current flowing between the electrodes produces an intense heat. A peculiar action now takes place, the theoretical explanation of which is in some doubt on account of obvious difficulties of observation; but it is thought that the action may be that the oxide of magnesia of which the electrodes are formed is decomposed, and

.almost immediately recombines, so that there is substantially no real or permanent combustion thereof. While in its decomposed state, however, it forms, in combination with the vapor emitted by the e-lcc' trode ends. or in combination with the fuel, a gaseous conducting path for the current, so that a greatly extended gaseous resistor can be formed with constant voltage and current factors. having the characteristics of an electric arc.

The electrodes may be adjustedto var the distance between them. With the specific adjusting mechanism shown, this can be done readily as soon as the fuel surrounding them has been partially consumed.

The heat is imparted to the carbonaceous fuel 40 within the receptacle. The fuel is heated to a temperature of incandescence. The incoming vapor is dissociated by the intense heat produced and thus an initial supply of oxygen at a high temperature is provided for combustion of the fuel. The combustion of the fuel and the current flowing between the electrodes cooperate to produce exceedingly high temperatures, and it is possible to obtain a temperature very high with respect to the theoretical temperature of combustion of the fuel.

The heat transmitted by conduction through the electrodes 20, 21, to their respective supports is imparted to the incoming stream of vapor. The vapor, although hot, is at a temperature considerably below the melting point of nickel chromium or other material of which the supports are made, and serves to limit the rise of temperature therein and prevent damage thereto.

During the early period of the operation, the vapor after serving its purpose, or the residue of the vapor escapes through leaks or crevices in the devices. Later the valve -36 may be shifted to interconnect passages 37 and 38 thus permitting circulation of the vapor in through one electrode and out through another.

In the modified form of electrode terminal shown in Fig. 4, the split collar 30 is fitted over the upper end of the respective electrode, the fit being sutliciently tight so that the collar is securely maintained thereon. The upper end portion of the electrode 20 may in this case be made solid, thus forming a conductor for the electric current. This portion 20 above the hollow interior chamber of the electrode proper, may be made of a differently characterized material, such as carbon. The lower portion of the electrode 20, and the transverse passage 31 leading to the hollow interior thereof is formed of the same material as and is similar in construction to, the corresponding portion of the embodiment of Fig. 3. Thus I have provided an electric fire pot in which an increased rate of utilization of the heat energy, usually expressed in British thermal units, contained in a given charge or mass of fuel is obtained, and which is compact in construction and simple in operation.

Illustrative apparatus has been described but it is expressly understood that the scope of the invenion is not to be limited thereby, reference being had to the appended claims for that purpose.

What I claim is:-

1. A fire pot having an outer radiating y surface and arranged to contain fuel, means for causing at least a portion of the fuel to incandesce, comprising electrodes extending into the fuel, and means for supplying an oxygen carrying medium through the electrodes to sustain combustion of the fuel.

2. A fire pot having an outer radiating surface and arranged to contain fuel, means comprising electrodes for incandescing at least a portion of the fuel, and means for supplying an oxygen carrying medium to the fuel to sustain combustion thereof.

3. A fire pot. having an outer radiating surface and arranged to contain fuel, electrodes extending into the fuel, and means for supplying a hot oxygen carrying medium to the electrodes to heat the electrodes and to supply oxygen to the fuel.

4. A fire pot arranged to contain fu l, a. plurality of hollow electrodes which are conductors of electricity only when hot, extending into the fuel, and means for supplying a hot oxygen carrying medium to the electrodes to heat the electrodes and to supply oxygen to the fuel.

5. A fire pot arranged to contain fuel, electrodes extending into the fuel, and means for supplying an oxygen carrying medium to the electrodes and to the fuel at a temperature above the ignition point of the fuel to heat the electrodes, to initiate combustion of the fuel and to sustain the combustion thereof.

6. A fire pot arranged to contain fuel, a plurality of hollow electrodes extending into the fuel. and means for supplying an oxygen carrying medium through the electrodes to the fuel at a temperature above the ignition point of the fuel to heat the electrodes. to initiate combustion of the fuel and to sustain the combustion thereof.

7. A fire pot arranged to contain fuel, hollow electrodes which are non-conductors of electricity at ordinary temperatures and conductors of electricity when hot. extending into the fuel, and means for supplying an oxygen carrying medium through the electrodes to the fuel at a temperature above the ignition point of the fuel to heat the electrodes, to initiate combustion of the fuel and to sustain the combustion thereof.

8. A fire pot arranged to contain fuel, means for causing at least a portion of the fuel to incandesce, comprising magnesia electrodes, means for supplying electric current to the electrodes, and means for supplying a hot oxygen carrying medium to the electrodes to heat the electrodes to render them electrical conductors and to the trodes and throughthe fuel, said electrodes being formed of material substantially chemically inert with respect to the fuel at incandescent temperatures.

10. A fire pot arranged to contain fuel through the electrodes into the fuel and means for passing a current of electricit between said electrodes through said fue 16. A plurality of electrodes, a mass of fuel surrounding said electrodes, a source of electric energy operatively connected with said electrodes, and means for introducing a flow of vapor for providing) a gaseous path of electric conductivity etween the electrodes.

I 17. A heater comprising a casing having an outer radiating surface and forming a substantially closed; space arranged to conand means for causing a portion of the tain a massof fuel,.and electrodes extending to incandesce comprising spaced electrodes mto the fuel, said electrodes being non-conextending into the fuel, and means for causing electric current to .flow between the electhe fuel having a carbonaceous chemical COIIIPOSltlOIl and means for incandescing attrodes and through the fuel, said electrodes being formed of an oxide of magnesia.

11. A fire pot arranged to contain fuel,

least a ortion of the fuel including spaced electro es of non-carbonaceous material.

12. A fire pot arranged to contain fuel having a carbonaceous chemical composition, means for incandescing at least a portion of the fuel including spaced electrodes of non-carbonaceous material, and means for supplying an oxygen c'arrying'medium to the fuel.

' 13. A fire pot, a plurality of hollow electrodes which are conductors of electricity only when hot, positioned therein, means for supporting the electrodes whereby they may be relatively adjusted, means for supplying a hot oxygen carryin vapor to the electrodes to heat the electro es and to supply the oxygen in the fire pot, and means for supplying electric current to'the electrodes.

14. A plurality of hollow electrodes which are non-conductors of electricity at ordinary temperatures and conductors of electricity when hot, means for passing a hot vapor through the electrodes, a mass of fuel surrounding said electrodes and means for passing a current of electricity betweeen said electrodes through said fuel to cause incan; descence of the fuel. 1

15. A plurality of hollow electrodes which are non-conductors of electricity at ordinary temperatures and conductors of electricity when hot, a mass of fuel surrounding said electrodes, means for passing a hot vapor ductors of electricity at ordinary temperatures and conductors of electricity when hot.

18. A heater comprising a structure forming a substantially closed space arranged to contain a mass of fuel, electrodes'which are non-conductors of electricity at ordinary temperatures, and conductors of electricity when hot, said electrodes being positioned to extend into the fuel, and means for heating the electrodes. I

19. A heater comprising a structure forming a substantially. enclosed space arranged to contain a mass of fuel, electrodes extending into the fuel and means for passing a vapor having a predetermined temperature into the fuel for controlling combustion thereof.

20. A heater comprising a container for fuel having an outer radiating surface, electrodes extending into the container, a source of electric current operatively connected with the electrodes and means for passing a heatedvapor into the fuel whereby heat is generated by the combined action of the electric current, the heated vapor and the combustion of the fuel.

21. A heater comprising a container for fuel having an outer radiating surface, a plurality of hollow electrodes extending into the fuel, a source of electric currentopera tively connected with the electrodes and

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