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Publication numberUS1392802 A
Publication typeGrant
Publication dateOct 4, 1921
Filing dateOct 31, 1919
Priority dateOct 31, 1919
Publication numberUS 1392802 A, US 1392802A, US-A-1392802, US1392802 A, US1392802A
InventorsLemuel W Serrell
Original AssigneeLemuel W Serrell
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electric fireless cooker and range
US 1392802 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)



APPLlcATxoN man ocT.31,1919.

1,392,802, Patented Oct. 4, 19.21`


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/d-` Afro/Mfr L. w. SERRELL. ELECTRC FIHELESS COOKER AND RANGE. APPLICATION FILED OCT, 31, [919. v 1,392,802. Patented Oct.

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Patented oet. 4, 1921,.





Application filed October 31, 1919.

To all whom z't may concern.'

Be it known that I, LEMUEL W. SERRELL, a citizen of the United States, and resident of the borough of Manhattamin the city, county, and State of New York, have invented a new and useful `Electric Fireless Cooker and Range, of which the following is a specification.

The object ofthe invention is to provide an electrical cooking apparatus, of moderate size and simple construction, combining in one oventhe capabilitiesof both a range and atireless cooker, and in theseA capabilities having special utility in respect to the amount and kinds of things that can be cooked, the adaptability and. convenience of the device for cooking different articles in the manner most edective therefor, and'its economy in' consumption of electrical energy.

rfhe oven as herein disclosed comprises a heat-insulated inclosure having a door and guides at different heights for racks. An

electrical heating element is disposed at the bottom of the oven, over a soapstone or equivalent heat-absorbing body, and another .electrical heating element is positionable at any height byv sliding it in and out on the wall guides. An important feature of the invention comprises vertical trolleys or continuous conductors by which this upper heater is supplied with current and with which it makes connection at any height.

lin practice l find it desirable to use a three-track trolley-or conductor system, and to arrange the windings in both the xed v bottom heating element and the movable heating element in such a way that the entire heat can be thrown into the bottom element or into the top element.or divided between the two elements, at will. lf it is desired to make more room in the coooker, the movable element maybe entirely removed, allowing more space for cooking utensils, but when using the oven as a grill or a range, the movable element is-prefen. ably placed in the oven at such elevationas to bring it close to the surface of the meat or whatever one desires to cook, so that the food is subjected to radiant heat from above, but preferably from both above and below, this mode of operation being suitable especially for cooking by the range process rather than by the fireless cooker process, although the fireless process can be used in Specification of etters Patent.

Patented Oct. 4, 192,1.

Serial No. 334,729.

conjunction therewith, as might be the case where a roast or poultry was to be cooked. rlhe movable element in such case may be placed close to the surface and by turning the current in both elements, a heat of approximately 12000 is developed, which quickly sears or browns the surface, thus keeping in the moisture and juices. Then the current is turned off and the roasting completed by the tireless process. Numerous other useful modes of cooking are made possible by the combination.

l also provide a movable cover or reflector for the lower heating element, whereby either the greater part of the heat generated by the coil can be stored in the bottom soap-1 stone to be given out over a prolonged period, or the element can be used as an open radiant grill,

To obtain the vgreatest eiiiciency in the reless cooker, the loss of the heat must be kept 'down to a minimum. To do cooking a certain number of heat units are required. Cooking, therefore, is not only a question of temperature, but a continuance of temperature and heat must be supplied from some source to make up losses due to conduction and radiation. `When heat is supplied to an oven through an internal heater,

.the oven air is first heated, that heat is absorbed fromthe oven air by the walls of the oven, and that no matter what insulation is used, the heat travels through the oven walls to the outer wall. As soon as the outer oven wall is raised to a temperature above the surrounding atmosphere, the oven loses heat by external radiation. llt is therefore essential that there be some form of a cake it is evident upon reliection that there must be some relation between the amount of heat absorbed by the soapstones, the amount of heat delivered to the oven air, and conse-l quently to the roven walls themselves, that will give when established a maximum eficiency in the utilization of the heat units centage of heat is absorbed by the soapstone than when the face of the heater is open to theoven air, that the inner oven walls heat more uniformly to the temperature of the oven air, that there is less loss of heat units by conductivity and radiation, and that the efficiency of the oven as a heat retainer can be practically doubled. I, therefore, provide at the bottom of the oven a soapstone of the proper relative size to the oven itself, placed on the top of which is a radiant electric heater covered over by a reflector or intercepter wherein the coils can be covered or uncovered at will, being covered when the oven lis to be used as a fireless cooker, in which case a very much greater amount of heat .units generated by the electricity is absorbed by the soapstone, while sufiicient heat is conducted through the closed cover plate to properly warm the oven air and the walls of the oven in a given time. Thus the total number of heat units generated by the electric heater are ivided up the most eiiicientlyand the oven 25 a1r and oven walls are heated with a minimum amount of loss of heat due to conductivity and radiation. so that when the current is turned off, the oven will take much longer to cool down to a predetermined temperature than it would without t-he arrangement mentioned.

When the oven, however, is used as an electric range, the advantage of the direct intense open radiant heat for quick cooking cannot be overestimated, and for this purpose the cover is moved, so that the heat from the coils may act directly on the broiling pan or other vessel that may be used.

n the accompanying drawings, forming a part hereof:

Figure 1 is a front elevation of an embodim-ent of the oven in which the outermost wall or inclosure at the sides and top is in the form of a removable hood;

Fig. 2 is a similar view with such hood removed;

Fig. 3 is a front elevation, looking at the interior, with the outermost wall in section l and the inner door broken away at its hinges,

illustrating one way in which food may be cooked;

Fig. 4 is a horizontal section looking down upon the bottom heating element, soapstone and register, a-portion of the latter being broken away to indicate the connections;

Fig. 5 is a view similar to Fig. 3 on a smaller scale, illustrative of the tireless cooking process with the upper heating element removed; v

Fig. 6 is a similar view illustrative of the range process, using both heating elements, theh outermost inclosure being dispensed wit Fig. 7 is a view similar to Fig. 6 looking down upon the upper or removable heating element, the plane of section being just below the top refiector plate of. this element;

Fig. 8 is an enlarged vertical section at the angle between one of the fixed side walls and the base;

Fig. 9 is asimilar view at the angle between the front door and the base;

Fig. 10 is an electrical wiring diagram;

Fig. 11 is an enlarged plan view of the register and the lower heating element, showing the outer part of the register closed and the inner part open;

Fig. 12 is a vertical section of the same taken in the direction of the longer horizontal dimension; v

Fig. 13 is a central vertical section at right angles to Fig. 12; and

Fig. 14 is a plan of the inner movable section of t-he register.

The oven is shown as comprising an oven proper 1 having heat-insulating walls and an outer inclosure 2 in the form of a removable hood spaced at top and sides from the outer wall of the oven pro er by an air space 3 forming a part or supp ementary part of the heat insulation. It is to be understood, however, that the `outer airspace-forming wall may be fixed and that I do not limit myself to the particular form and proportions of the heat insulation, which I prefer to constitute, however, by a thickness of asbestos or equivalent material 4 for the inner part and an air space for the outer part. If desired, insulation of one kind only can be employed. In the particular construction shown, the fixed walls comprise inner and outer approximately cubical shells 5 and 6, with the heat non-conducting filling 4 be-1 tween them. The joints where they occur in the inner shell, as at 7 in F ig. 8, are closed, so as to prevent access of molsture from the interior to the insulation 4, and the shells are so constructed that metal contact between them is avoided, heat insulation spaces 8 being interposed at the regions where the shells would otherwise bear upon each other. The front of the part of the inclosure which has been termed the oven proper is formed by a door 9 swung on side hinges 10 and of similar construction to the fixed walls, being formed of inner and outer shells 5a and 6a with interposed insulation 4l and insulation spacers 8a at the joints. The edges of the door are beveled to fit a correspondingly beveled frame 11 held out of metallic contact with the shells 5 and 6 by insulation spacers 8 and 12.

The youter portion 13 of the base is continued in the form illustrated to provide a sloping ledge with Seat 14 for the lower edge of the hood 2; and outside of said seat is a trough 15 to catch any condensation. A vent 16'(Fig. 3) passing through the shells 5, 6 and insulation 4 at the top permits steam to escape so that the cooking takes place without pressure; and the steam may be delivered into the air space 3, there to condense and give `up. its latent heat, though this is not essential. The front of the inclosure 2 `has a door 9a, the opening of which is large enoughtoenable the door 9 to be opened without tak-ing off the hood. suitable temperature'` indicator 9b is mounted in the inner door, and may be seen through a window in the outer door,

The interior of the oven, at opposite sides of the doorway is provided with horizontal ledges 17 extending from front torear and forming guides whereon removable and adjustable racks 18 may be slid to support the food and, utensils. The same guides are also adaptedto receive laterallyprojecting lugs 19 on the frame 20 of an upper, movable electrical heating element 21, which can be placed at any height desired.

In the bottom part of the oven interior is a relativelylargesoapstone slab 22, suitably held by clips 23 and resting on ribs 24 (Figs. 8 and 9), whereby a small air space is left between it and the bottom of the shell 5, the edges ofthe slab bein likewise spaced from the inner side walls. he dimensions of this slab can advantageously be approximately as shown in the drawing, though needless to say ,the exact size can be varied.

A lower electrical radiant heating element 25 in a suitable frame 26 is mounted 'on said bottom soapstone 22, where it may be held by suitable clips 27. As shown more particularly in Figs. 12 and 13 the coils of the element are supported in an open inner frame 28 of porcelainor other insulation, so that they are exposed atthe under side to the soapstone or heat reservoir beneath. 'At

the upper side they can be covered or uncovered by means of a movable heat-intercepter or reflector, represented by a register 29. The function of the movable cover is to cause the heat from the coil to be ,thrown into the stone or to permit it to be used for direct radiant cooking, at will, and its form may be varied. The register shown in the. drawing comprisesy an upper, fixed' plate 30 slotted in vertical coincidence with the coils, -and under slidable plates 31, 32 similarly slotted and adapted to be moved to open or blank the stationary slots. The movable register member 32 is located preferably at the middle and is of comparatively small area and generally circular, and occuv pies an opening in the outer mem'ber 31, which openingis large enough to permit of independent movement of the two members. rPhe inner member may be guided by pins 33, projecting downward from the Vstationary top plate into slots 34 in the inner member, and has a forwardly'extending stem l35 terminating in an accessible finger-piece 36.

-The outer section 31 has another forwardly projecting handle' 37 and the relations are latter view pushing in on the handle 37 will open the outer section, with the result seen in Fig. 4, and pulling out on the handle 36 will close the inner section, both sections being then closed. l

The upper,l movable heating element is similarly constructed and mounted, and could also be provided with a register at one side, but vfor most purposes it will be suficient to furnish it with a xed cover plate 38, which will cause it to throw its heat downward. If desired toradiate upward, the heating element can be turned upside down on the guides.

As shown in Fig. 7 the coils ofthe movable heating element 21 are connected alternately in series, the current 4passing from one of two outside terminals 39 at the back i through every other coil to the front, and then through the remaining coils to the backy and` out at the other terminal 39. A middle conductor 40 is connected to the forward coil and extends, without connection with the other coils to the back, to a mid-terminal 42.` By outside and mid-terminals I do not mean necessarily that the terminal 40 is between the terminals 39, but that the termi nals 39 are at the ends.of the complete heating element, whereas the terminal 40 is connected-to furnish a.return path for the cur` rent, under certain conditions, after it has traversed only half or other part of the n ,bers adapted to slip into and out of connection withtriple conductors 41, 41, 42, which extend up the back of the interior ofI the oven from the bottom, theconstruction being such that the terminals are adapted to s lip automatically into and out of connection with the fixed conductors at any height, by the mere act of inserting or removing the 'heating element on its guides 17. This may be accomplished in a variety of ways, but preferably the conductors or trolleys consist of bars projecting from the backs of channels in an insulation member 43, while the terminals are spring clips formed to embrace these bars. 4

The lower heating element is similarly wired, but in this instance the Aoutside terminals 39n are fastened to 'suitable binding posts 44 on the bottom. The mid-terminal 40"L is a contact like those of the upper element,l to connect with the conductor 42. The

conductors 41` are represented as connected 'with v.binding posts 45 on the bottom of the interior. The binding posts 44, 44, 45, 45 are connected with four main terminals 46,v 47,

48, 49, adapted to be connectedfin diferent pairs with an outside circuit, terminals of which are represented yat 50 and 51. Referring to the dlagram of Fig. 10 and assuming the movable heating element 2l to be in place in one or other of its positions, current is caused to flow through one or elther of the elements in its entirely, or can be divided between the two. Thus if the outside circuitl is connected with the terminals 46, 47, the current will enter the lower heating element 25 only, and will pass through all of its coils. .When the terminals 47, 48 are selected the current iows through one part of each of the elements, these parts being connected in series by the said terminals 40, 40a, the trolley conductor 42 and one of the conductors 41, and the other parts of both elements being cut out of circuit. Finally, when terminals 48 and 49 are connected with the outside circuit, the upper element only receives the current, which traverses al1 of its coils, by way of the conductors 41.

A relatively thin soapstone 52 is supported in the upper part of the interior slightly spaced from the top inner wall, and also from the side walls. Clips 53 are lindicated for holding the soapstone in a removable manner, it being desirable to take out both stones occasionally for cleanin While I have used the term soapstone, as 1t appears to be the best and typical example of a heat-absorbing reservoir or cake suitable for the purpose of fireless cooking, it is to be understood of course that I do not limit myself to one material.

The cooker constituted as described is serviceable fora variety of cooking operatlons and takes the place of both the range and the ireless cooker. For tireless cooking, the upper heating element may be removed if it is in the way, and any appropriate number of racks 18 are inserted to support the vessels containing the food (Fig. 5). The oven is closed and the current turned on into the lower heating element, the register 29 over this element being closed. The heat given off-from the radiant coils is largely taken up by the bottom soapstone 22, and enough passes through the cover to heat the air, the food and the walls to the desired temperature. The current is then turned oil", and the food left to cook by the heat confined in the oven and gradually given ofi' by the soapstones.

In the case of roasting or baking, it is desirable to use both heating elements, `above and below. the food. Thus, as shown in Fig. 3, the baking pan or other receptacle can be placed directly-on the frame or register of the bottom heater, and the upper heater can be disposed close over the fowl or other article, with its radiant coils facing downward. In this` way the surface can be nicely browned or seared, and the 'cookcan be saved and oApening only the portion 32 of the register.

ing of the interior completed in the ireless wa after the current has been turned off.

r the oven can be used as arange, without the hood or outer inclosure 2 if desired, and with the door open or not as desired. In such case, for example, steaks, chops and other articles can be quickly cooked between the upwardly and downwardly striking radiant heat from both heating elements, the register 29 being open. The pan or other receptacle can be placed on the open register, or supported at a greater or less elevation by one of the racks 18, as seen in Fig. 6, and the yupper element can also be placedat any desired height. In this form of cooking the lower heating element alone can be used, or all the current can be thrown in the upper, movable element if for any reason desirable. When making coiee or heating any small bottomed vessel, current the action hastened by t the same time other articles can be heated inthe upper partl of the oven, or upon the closed part of the register. Numerous other modes of use are also possible.

What I claim as new is:

1. In a cooking apparatus, an oven, a movable electrical heating element adapted to be supported in the oven at various heights, and continuous vertically extending stationary conductors coperative with said heating element at any height.

2. In a cooking apparatus, an oven pro vided with guides, vertical conductor trolleys at thev back of the oven, and a removable' lelectrical heating element adapted to make connection with said trolleys at any height.

3. In a cooking apparatus, the combination of an oven provided with guides, an electrical heating element at the bottom of the oven, an upper electrical heating e1ement positionable at various heights, and vertical conductor trolleys for coperation with said upper element.

4. In a cooking apparatus, the combination of an oven, a lower electrical heating element, an upper electrical heating element positionable at different heights, and means for supplying current to the entirety of either one of the elements or connecting halves of the two elements in series with the supply circuit at will.

5. In a cooking apparatus, the combination with an oven, of upper and lower electrical heating elements therein, each of said elements having three terminals, means for connecting the mid-terminals of the two elements, andv means for selectively connecting the outside terminals of the elements with a supply circuit, whereby the current may be caused to pass through the whole of either element or through half each of both elements in series, at will.

6. In a cooking apparatus, the combinationof an oven, a lower electrical heating element, an upper electrical heating element, positionable at different heights, each of said heating elements having two outside terminals and a mid-terminal, four main terminals, and three conductors with which the terminals of the movable element engage, two of said conductors being connected with two of the main terminals, the outside terminals of the lower heating element being connected with the other, two main terminals, and the mid-terminal of the lower element being connected with th third conductor.

7. In a cooking apparatus, a heat-insulated oven, a heat-absorbing body therein, an electrical heating element immediately over said body, and a register over the heating element.

8. In a cooking apparatus, the combination of a heat-insulated inclosure, a heatabsorbing body therein, an electrical heating element immediately over said body, and a movable cover for the heating element whereby the'heat can be forced principally into the heat-absorbing body to be given out over a period, or the radiant coils exposed for direct cooking, at will.

9. In a cooking apparatus, the combination of a heat-insulated inclosure, a heatabsorbing body therein, an electrical heating element immediately over said body, and a register over the heating element comprising outer and inner parts, both of which, or the inner part alone, can be opened at will.

10. In a fireless cooker, the combination of an oven having heat-insulating walls with a door in one sidev and guides for the racks, an electrical heating element and a heat-absorbingv body therein, a hood inclosing the oven with air space between, and a steam vent from the oven into said air space.

11. In a ireless cooker, the combinationof an oven having heat-insulating walls with a door in one side and guides for racks, an electrical heating element and heat-absorbing body in the oven, and a removable hood adapted to surround the oven in spaced relation and having a door outside the door of the oven.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2466349 *Nov 17, 1943Apr 5, 1949Mccord CorpElectric cooker
US2984730 *Feb 26, 1957May 16, 1961Electrolux AbMulti-purpose cooking unit
US3358120 *Sep 28, 1965Dec 12, 1967Westinghouse Electric CorpOven
US4164643 *Mar 6, 1978Aug 14, 1979Dewitt David PEnergy-efficient bi-radiant oven system
US4215266 *Dec 21, 1978Jul 29, 1980Smith Gilbert LBaking oven
US4238669 *Apr 3, 1978Dec 9, 1980Huntley James HOven having dual heating means
US4455319 *Jul 6, 1982Jun 19, 1984Toastmaster, Inc.Method of effecting long wavelength radiation cooking
US4942288 *Mar 10, 1989Jul 17, 1990Worsham Dillard DBaking oven
US8680439 *Dec 21, 2012Mar 25, 2014Duke Manufacturing Co.Rethermalizing apparatus
WO2010075079A1 *Dec 15, 2009Jul 1, 2010Conair CorporationOven with improved toasting function
U.S. Classification219/395, 219/404, 219/410, 219/507, 219/474, 219/540, 439/110, 219/414, 219/541, 219/399
International ClassificationF24C15/08, F24C7/06
Cooperative ClassificationF24C15/08, F24C7/06, F24C15/166
European ClassificationF24C15/16D, F24C15/08, F24C7/06