US1081233A - Electric heating element. - Google Patents

Description

` invention; Figs. 2 and 3 i parts may be results.

DAVI) HUNTLEY, DE LONDON,

ENGLAND.

ELECTRIC HEATING ELEMENT.

Specification of Letters Patent.

Patented Dec. 9, 1913.

Application led February 8, 1913. Serial No.. 747,174.

To all tti/1,0m t may concern:

Be it known that l, DAVID HUNTLEY, a subject of the Kingjot England, and resi# dent; of `London, England, have invented certain new and userul improvements in New or improved Electric Heating Elements, of which the following is a specification. l

The object of this invention is to produce a strong, compact electric heating element, of simple construction, easily handled, readily replaceable, and in which the various removed with great facility and by persons of ordinary skill but with out technical or electrical knowledge.

Heretofore mica and asbestos have been employed as insulators in combination with resistance wires, strips or tapes in the construction ot electric heating elements, but it has been found that when heated to a high'temperature the mica or asbestos chemically atl'ects the metal or alloy and produces more or less rapid oxidation, and a reduction of the sectional area-of the Wire, strip, or'tape, and consequently sets up a greater resistance locally and ultimately causes the destruction of the metal. This is believed to be due to the presence of metallic or other substances in the mica or asbestos which produce chemical action when in contact with the metal or alloy, which action is increased Y by the presence ot the electric current but it has been' found that neither of these insulating materials used alone yield satisfactory Other substances such as porcelain, glass, fireclay, quartz, or the like, have been employed for inclosing or supporting the resistance wires, strips, or tapes, but I pret'er to use a combination of insulators and supports as hereinafter described,

Figure 1 of the acconn'ianying drawings illustraties in front view an electric heating elementconstructcd in accordance with my are longittuilinal edge and end Views respectively of Fig. l; Fig, 4 is afront elevation ot' a heating' stove illustrating one application ot my improved i electric heating elements; and Fig.` 5 is a side elevation of the same stove with the portion upon which the heating elements are mounted turned down to," ythe purpose ot' examination or repairs.

Similar letters or reference relate to like parte` in all tbe figures of the drawings.'

Referring to Figs. l, 2 and t-. n is the base tormedof tireclay'for example, or ot other 'plate or slab are connected may be left at the top material of a. refractory and highly electri cal insulating character, in the face of which is molded or otherwise formed a recess b preferably of zigzag shape with rounded corners as sho n, and'extending from end to end of the base a. c is a helical Wire coil' ot' metal or alloy of relatively high resistance which is laid loosely into the recess I). d is a plain plate or slab of quartz or fused silica, preferably of the same length and width as the i'reclay base a and arranged t0 cover the resistance coil c. In some cases the outer surface of the plate or slab al may be corrugated to form a greater surface for radiation or broken up into any convenient pattern. The iireclay base .o and the quartz together at one or both ends by means of caps or clamps e which may be conveniently formed of sheet brass or other metal bent or stamped into the shape shown and carrying terminal or contact screws f by which the ends of the resist-ance coils c are removably connected to the caps or clamps e for conducting the current vinto the said resistance coils c. Or such connection may be effected in any other suitable manner.

If desired more than one resistance coil c may be laid into the recess b, or instead of such coils one or more strips of metal or alloy ot' relatively high resistance may be employed.

I'soinetimes inclose the back ireclay base a 1n a metal or other closed casing or jacket y (Fig. 3) with a Space l2,`

between, thereby preventing too rapid radiation of the heat from the back of the tireclay portion t of the element. And when it is desired to'carry oil' the heat, openings ing or jacket g, thereby allowingfor thecirculation of the air.

The metal caps or clamps c arepreferably provided with a flange c' by which any desired number of elements may be readily connected to a metal conductor plate by means oi screwed studs 7' and wing-nuts (Figs. 4l and 5) or by other suitable devices. And 'in order to retain the quartz plate or slab (Z firmly in place, one or more portions of the caps or clamps e may be slit, as shown at m t'or example, and bent' inward so as to bear upon the quartz plate or slab with a more or less yielding or resilient, pressure.

These completed elements may be employed for a great variety ot' purposes, such portion of the and bottom of the casssl Cri

electric radiators, electric ovens7 or other electric cooking 0i' heating appliances, their shape and simple Construction enabling them te be applied in a very easy and ef- Yl'eel'ive. manner. For exemple, they nnLy be made to forni horizontal luminous bays in in electric radiator stove, :1nd Lhey muy be provided wiix bent el' corrugated ie'lecing surfaces al mie bzicli thei'ee'f, se ab' 'ie :is-eist or increase the circulation 01 the mii, und ielleet ille heat :myn: Buch :in electric rsidiaoi' suive is illnrfei'ulfed in Figs. l und in which four elein'eiiis constructed as hereinhelei'e described Willi reference Lo .Fil l 2 land 3 are shown inuunied in u heiizen tul peeitien (ly means of 'ille wingnus 17a) upon vei'ieally disposed conductor plates n which are attached by Screws 0 and nnte ',v le die buse plaine y lil-0in which they iii'e el tiieully insulated by means eil Lhe mishe, v", rlhe brise pluie g is mounted ngen the Duel; plante :i el" the Stove :it zi Suimbie di tenue therefrom :is shown, and @bhe seid heel: :plaie s is hinge-jointed at t ie the ixed pei'tzien u ef the steve so hat may he znned down inte the position. shown in if@ 5.2 for examination or i'epuii'ea oy be Lui-ned up intelhe Closed oi' working `pesition and iet-:lined therein by the turn-but- 'lun er. w :ire beni plaies el' bleek plzwirgheo. steel ei the like :itin/hed te the Las@ niet@ Q between lle eleinenls S0 is te give lille z l l l l l l l l l l i l l i l i in relation to the switches 0J thai. the whole or part of the elements muy be :in'inehed on ei' eli' aeeoiding le reqnii'einent'-,

ln Figs. l and the heated dir ehznnbei fix ie seiniiaed frein the lmcls of the elements ny die bei-e plaie g, bul; it

that portions the eid plaie may he se fut and lient as lie hiciese he @if each elen'ivntfse ihm; ih@ l li su *es el lhe lii'eeiziy lmes y, 'wen l tm'in p rtien# the well el'. me l n' chain-- bei' ./LX.

The easing i5 em'e ed :it the freni., by i am'een e; gm@ v wing new :l'dlljf7 de `C1filzed my i veniion, *what l elziiin and desil'a'; Le secure l an elem' lll ie combihinged menieine',

ies el condi ed apen the p w zii-illy pr-93 e Li n liars and fre-1n he plaie and he for eeein'nig sind conduction u1 n plate and ineens fer eeni'elling ehe el Cirie Supply.

in eslnnony wheres' in y hund in pres ebvimxs

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