US1910700A - Electric radiant range - Google Patents

Description

May 23, 1933. L. LEBAU ELECTRIC RADIANT RANGE Filed Jan. 25, 1952 2 Sheets-Sheet l INVENTOR.

BY ZaZA M A TTURNEYS- May 23, 1933. L. LEBAU 1,910,700

ELECTRIC RADIANT RANGE Filed Jan. 25, 1932 2 Sheets-Sheet 2 IN VENTOR.

A TTORNE Y8.

Patented May 23, 1933 LOUIS LEBAU, 0F PITTSBURGH, PENNSYLVANIA ELECTRIC RADIANT RANGE Application filed January 25, 1932.

This invention relates to improvements in electric radiant ranges or stoves especially adapted for cooking purposes.

Heretofore, so far asI am aware, electric ranges or stoves have had a resistor element carried by a base plate formed of china or other brittle material, the latter having the resistor elements either embedded therein completely, or, in some instances, having a coiled resistor element loosely held in open grooves below the level of the upper surface of said plate.

In such constructions, the cooking uten sil is placed directly on the china base plate in order to obtain sufiicient heat, and this frequently results in fracturing the plate, due to impact. Liquids are frequently spilled during the process of cooking, and upon striking the hot china base plate, cause the same to disintegrate by producing small cracks therein.

Further in the case of the open top plate having the coiled resistor element loosely held in open grooves, there is danger of short circuits from spilled liquids. The contact of the liquid with the hot resistor element may cause the latter to warp or buckle into contact with a metal utensil or the metal of the range, causing current to flow and possibly result in injury.

VVith'units of the above character, it has been dangerous as well as impractical to employ metal grids or gratings similar to those used in; gas stoves, since the grating would necessarily have to be placed at such a distance therefrom as to render the unit incitic-ient.

- It is a prime object of my invention to providean electric range or stove construction havingan electric heating unit therein, ineluding a resistor element carried by a heatreflecting plate or block, an open-work retractory radiant member superimposed thereon for securely retaining said resistor element on the plate, and a metallic grid or grating member extending over the radiant member in close proximity to the resistor element for supporting cooking utensils thereabove.

A further object is to provide cooperating Serial No. 588,517.

passages in the heat-reflecting blocks for ad initting air to the resistor element, for heating the air and moving the same upwardly to assist the transfer of heat for the purpose intended, said passages also functioning in connection with a slotted resistor elementand the open-work radiant member to permit ready drainage of fluids through the heating unit.

Additional objects and advantages will be come apparent from the following descrip tion taken in connection with the accompanying drawings, wherein:

Fig. 1 is a perspective view of an electric range embodying my invention;

Fig. 2, an enlarged vertical section taken on the line II-II of Fig. 1;

F ig. 3, a top plan view of the heat-reflecting plate;

Fig. 4, a bottom plan View of the radiant member, particularly showing the electric resistor element positioned therein; and i Fig. :5, a bottom plan View of the metal grid or grating.

Referring to the drawings, the range or stove, somewhat diagrammatically shown in Fig. 1, consists of a body portion 2 constructed in the conventional manner of sheet metal or the like, and has a top 3 positioned thereon. The top may be formed with one or more openings at therein for receiving the heating units, a single unit range being illustrated in Fig. 1.

It will be understood that various designs of ranges or stoves may be employed in connection with my invention to provide an efficient and attractive assembly.

The heating unit is of the electric radiant type shown in my pending application Serial No. 435.468, filed March 13, 1930, and in my companion application filed herewith, Serial No. 588,518. Said unit includes a heat-reflecting plate or block 5 of suitable material capable of reflecting heat and having insulating properties.

For example, the plate or block may be formed of fire clay prepared with sawdust or the like and kiln fired to burn out the sawdust and form a more or less porous body. Such material, when formed into a plate or block of substantial thickness, will properly insulate the range or stove and will provide a face or surface which, when subjected to the extreme heat of an electric resistor element, will attain a high temperature and glow with a red color. The applied heat w ll penetrate the plate or block but a slight distance'due to the insulating qualities of the material. The hot surface area of the plate acts as a reflector to reflect and radiate heat therefrom.

As illustrated, the reflector plate comprises a body of rectangular shape having the top or heat-reflecting face thereof formed with a rectangular depression or recess 6. Positioned in the depression or recess, I provide a lurality of spaced-apart parallel horizontal y extending ribs or projecting elements 7, preferably formed integral with the bod i Elements 7, as shown and as preferred, are narrow in width and are arranged in groups of three, each group consisting of outer ribs a and a central rib I), and are spaced to produce horizontally extending air passages 8. The groups are also spaced apart to provide intervening horizontal spaces or grooves 9 for a purpose hereinafter described. A series of air ducts or openings 10 are also provided and extend vertically through the plate 5 from the communicating air passages 8.

In connection with such a back wall or reflector plate, I prefer to employ a flat resistor element formed of thin metal strips 11 having narrow spaced-apart slots 12 cut therein alternately from the edges of said strips to provide a sinuous path for the current. The said strips 11 are of substantially the same width as thedistance between the outer ribs (1 of each group hereinbefore described, and are positioned thereon to lie flatwise in'a horizontal plane.

When the resistor strips 11 are thus positioned on the ribs 7, one strip for each group of three ribs, adjacent strips are electrically connected by portions 13, either at the upper or lower portions of the ribs. For this purpose, the end portions of the outer ribs a of adjacent groups are cut away, as at 14, to accommodate the connecting portions 13. The central ribs 1) of each group serve to support the thin flat resistor elements and prevent buckling or distortion.

Superimposed upon the block or reflector plate 5v is an open-work radiant member 15; this radiant member is formed of refractory clay or the like and includes irregular connecting face portions 16 separated by openings 17 worked into an attractive design. The radiant member substantially conforms in shape and size to the depression 6 of the plate 5, and has a downwardly depending mar inal flange 18 for entrance in the outer portion of said depression.

Radiant member 15 is provided with spaced-apart vertically extending ribs 19 adapted to be positioned in the spaces or grooves 9 between adjacent groups of reflector plate ribs 7, as particu arly shown by Fi 2. Said ribs 19 are cut away at their en portions, as at 20, to span the connecting portions 13 of the resistor strips.

The under face of the radiant member 15 contacts with the resistor elements or strips 11 to securely maintain the same flat against their supporting ribs 7. The ribs 19 and vertical portion of the marginal flange 18 cooperate with grooves 8 and the depression 6 to prevent lateral movement or disengagenient of the resistor strips 11.

Positioned directly on the radiant'member 15 with its under surface contacting the upper surface of said radiant member, I pro vide a metal grid or grating member 21 preferably formed of cast iron or the like, consistin of a marginal frame portion 22 and radia ly extending spaced-apart members 23 arranged to form a grating for supporting cooking utensils thereon. The said grid is relatively thin and is spaced but a slight distance above the electric resistor elements 11, thus providing for the efficient heating of a utensil or the like placed on the grid member.

Screws or bolts 24 are passed through the grid member and the reflector plate 5 to secure said member thereto and securely hold the radiant member 15 in position on the resistor elements. Downwardly extending projections or feet are provided on the grid member for extending and resting in the depression or recess 6 in the top of the reflector block.

Depending ribs 26 are also provided on the under side of the grid member 21 for embracing and securing the radiant member 15 against lateral movement.

The heating unit is supported as a whole in the opening 4 of the range top 3 so that the upper surfaces of the grid member 21 and said range to lie in the same horizontal plane. For t is purpose I provide angle members 27 embracing opposite lower edges of the reflector plate. Said angle members may be secured to the said plate by bolts 01' screws 25 as shown or in any suitable manner.

The angles 27 and hence the heating unit is supported by cross angle members 28 becured to the range body as at 29. Bolts or other means may be em loyed in securing said unit in position on t e angles 28.

The body of the range is provided, preferably at its rear wall, with a series of openings 30 for the purpose of admitting air to the interior thereof and to the heating unit. For this purpose the interior of the range is sufiiciently large to provide an air chamber 31 below and around the heating unit to permit the air to circulate from the openings 30 upwardly through the said unit.

In the operation of my invention, the terminals of the resistor element are connected with a source of electrical energy in any suitable manner through a control switch indicated at 32. When the switch is turned on, the resistor element 11 becomes heated and imparts heat to the reflector plate 5 as described.

Due to the open slots 12 in the resistor element, the air passages 8 and the vertical ducts or openings 10 in the reflector plate, an upward circulation of air is induced by the heatof the element, the air drawn into chamber 31 through the openings 30 in the body of the range passes upwardly through the chamber. The air in passing through the resistor element becomes heated and passes upwardly through the open-work radiant and grid members where its heat may be utilized for cooking purposes.

In the event that fluids are spilled on the range and the heating unit, they will be speedily drained through the radiant, resistor and reflector plate to the chamber 31 therebelow where they may be collected and removed by means of a tray The resistor element is securely held between the radiant member and reflector plate, and therefore it is impossible for it to become warped or distorted.

With my construction maximum current may be initially applied and continued for a short time or until the heating surface of the reflector plate reaches a red heat after which the current may be considerably reduced and continued at the reduced Value without a reduction of the heating medium to a point below satisfactory cooking temperature, thus providing an electric range that may be operated at a minimum cost.

What I claim is:

1. An electric radiant range including a heating unit including a reflector plate having an air passage in the top thereof and a communicating opening extending through the plate, an electric resistor element dis= posed on the plate adjacent the air passage, an open-work refractory radiant member superimposed on the plate and over the resistor element, and a grid member positioned over said radiant member.

2. An electric radiant range including a heating unit comprising a reflector plate having an air passage in the top thereof and a communicating opening extending through the plate, an electric resistor element on the plate adjacent the. air passage, an open-work refractory radiant member superimposed on the plate and over the resistor element, and a metal grid member positioned over said radiant member.

3. An electric radiant range including a heating unit comprising a reflector plate hav ing an air passage in the top thereof and a communicating opening extending through the plate, an electric resistor element on the plate adjacent the air passage, an open-Work refractory radiant member su aerimposed on the plate and over the resistor element, and a metal grid member positioned over said radiant member and secured to the reflector plate.

4. An electric radiant range having an air chamber and an air opening therein, a range top having an opening therein, a heating unit positioned in the said top opening and including a reflector plate having air passages therethrough communicating with the air chamber, a flat slotted electric resistor element on said plate and extending over said air passages, an open-work refractory radiant member superimposed on the plate and engaging said resistor element, and a metal grid member disposed over said resistor element and spaced therefrom by the radiant member.

5. An electric radiant range having a top formed with an opening therein, a heating unit positioned in said opening and including a reflector plate having air passages there through, a flat slotted electric resistor ele ment on said plate and extending over said air passages, an open-work refractory radiant member superimposed on the plate and engaging said resistor element, and a metal grid member positioned on said radiant memher with its upper surface in alinement with the upper surface of the said range top.

(3. An electric radiant range comp-rising a hollow body having an air chamber and an air opening therein, an apertured range top, a heating unit for the range including a reflector plate having air passages therethrough connnunicating with said air chamber, a fiat slotted electric resistor element on said plate and extending over said said air passages, an open-work refractory radiant member superimposed on the plate and engaging said resistor element, a metal grid member on said radiant member. and means in the air chamher for supporting the heating unit.

In testimony whereof I afiix my signature.

LOUIS LEBAU.

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