DK157284B - Procedure for production of an electric thermal radiation element - Google Patents

Abstract

Procedure for production of an electric radiating heat element, the procedure having a spiral wire (21) electrical heat resistor fixed to an insulating carrier (20). According to the invention the spiral wire (21) is pressed into the face of the essentially flat-formed fibre-containing plastically deformable insulation carrier (20), after which the insulation carrier is set upon drying. The spiral wire (21) is thereby fixed directly into the insulation carrier without further attachment agents, such as wire tacks or the like, whereby the procedure will be able to be carried out in a relatively short amount of time.

Description

DK 157284 BDK 157284 B

Opfindelsen angàr en fremgangsmâde til fremstilling af et elektrisk varmestrâ1ingselement, ved hvilken fremgangsmâde en som trâdspiral udformet varmemodstand nedsænkes i et fiberhol-digt isolerende materiale indeholdende en isolerende bærer, 5 der derefter hærdes eller torres.The invention relates to a method for producing an electric heat radiation element, in which a heat resistance-shaped heat resistance method is immersed in a fiber-containing insulating material containing an insulating support, which is then cured or dried.

Norsk patentskrift nr. 69.901 viser en ubetydelig indtrykning af varmespirâler i en isolerende bærer bestàende af et kera-misk hærdet materiale. Varmeviklingerne indtrykkes kun sâ me-10 get, at de fastholdes til materialet. Varmeviklingerne kan imidlertid frigores som folge af de forskellige varmespændin-ger i iso1erings1egemet og varmespira 1 en.Norwegian Patent No. 69,901 discloses a negligible impression of heat coils in an insulating support consisting of a ceramic cured material. The heat coils are only pressed in so that they are held to the material. However, the heat fluxes can be released as a result of the different heat stresses of the insulator and heat sink in one.

Formâ1 et med opfindelsen er at anvise en f remgangsmâde til 15 fremstilling af et udstrâlende varmee 1 ement, der pâ en for-holdsvis enkel mâde og uden yderligere fastgorelseselementer muliggor en sikker befæstigelse af de elektriske varmemod-stande i isolationsbæreren, og hvor de elektriske modstande har gode udstràlingsegenskaber og lang levetid.It is an object of the invention to provide a method for producing a radiant heat element which, in a relatively simple manner and without additional attachment elements, allows a secure attachment of the electrical heat resistances in the insulation carrier and wherein the electrical resistors has good radiating properties and long life.

2020

Dette formâl er ifolge opfindelsen opnàet ved, at trâdspiralen over en de! af sin hojde indtrykkes i en forberedt plastisk deformerbar isolerende bærer med en i det væsentlige pladefor-met overflade og i en sàdan grad, at det isolerende materiale 25 kun i mindre mængde trænger ind i mellemrummene mellem vindin-gerne af trâdspiralen og i vid udstrækning kun omslutter trâ-dene og i vid udstrækning frilægger det frie indre af trâdspiralen fra isolationsmaterialet.According to the invention, this object is achieved by the coil of a wire over one of them! of its height is pressed into a prepared plastic deformable insulating carrier having a substantially plate-shaped surface and to such an extent that insulating material 25 penetrates to a lesser extent only between the windings of the wire coil and to a large extent only. encloses the wires and largely exposes the free interior of the wire coil from the insulation material.

30 Trâdspiralen fastgores derved direkte til isolationsbæreren uden yderligere fastgore1sesmid1er sàsom kit, trâdstifter eller lignende, hvorved fremgangsmâden vil kunne gennemfores pâ forholdsvis kort tid. Trâdspiralen er desuden sikret mod ind-flydelsen af varmeudvide 1sen.The wire coil is thereby fastened directly to the insulation carrier without additional fastening means such as kits, wire pins or the like, whereby the method can be carried out in a relatively short time. The wire coil is also secured against the influence of heat expansion 1sen.

Indtrykningen kan med fordel foretages under presningen af isolationsbæreren. Derved spares et yderligere procestrin. De 35 2The impression may advantageously be made during the pressing of the insulation carrier. This saves an additional process step. The 35 2

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enkelte vindinger af trâden virker ogsà som et gitter, der i overvejende grad tilbageholder de fiberholdige materia 1er , sâ-ledes at kun bindemiddel eller korte fibre vil kunne trænge ind i det indre af spiralen. Spiralerne er ogsâ kun i et nedre 5 omrâde omsluttet af isolationsmateriale, men ogsà i dette om-ràde bliver den evrige de! af spiralens indre holdt fri, sâ-leaes at der i dette omrâde dannes en fordybning i isolations-bæreren. Derved er det indre af trâdspiralen ikke forhindret i at blive bestrâlet, og den udstràlende flade er overfor en 10 ikke-indlejret trâdspiral kun afdækket i ganske ringe grad og kun ved den flade, der vender mod den side, ser skal opvarmes.Some coils of the wire also act as a grating that largely retains the fibrous materials, so that only binder or short fibers will be able to penetrate the interior of the coil. The spirals are also only in a lower area enclosed by insulating material, but also in this area the eternal they become! of the interior of the coil kept free, so that in this area a recess is formed in the insulation carrier. Thus, the interior of the wire coil is not prevented from being irradiated, and the radiating surface facing a non-embedded wire coil is only slightly exposed and only at the surface facing the side must be heated.

Det er fortrinsvis kun en lille del af h ver vikling af trâdspiralen, der er indlejret, idet det evrige omrâde af spira-15 lens omrâde holdes fri.Preferably, only a small portion of the rear winding of the wire coil is embedded, keeping the eternal area of the coil area free.

Det isolationsmateriale, hvoraf isolationsbæreren bestâr, inde-holder fibre, der fortrinsvis er forsynet med bindemiddel. Trâdspiralen indpresses, medens isolationsbæreren endnu er 20 bled henholdsvis plastisk deformerbar, hvorefter der foretages en terring eller hærdning henholdsvis brænding t i 1 fasthol-delse af trâdspiralen.The insulation material of which the insulation carrier consists contains fibers which are preferably provided with a binder. The wire coil is pressed while the insulating carrier is still 20 blades or plastic deformable respectively, after which a ring or cure or firing t is made in 1 holding the wire coil.

Opfindelsen skal nærmere forklares i det folgende under hen-25 visning t i1 tegningen, hvor f i g. 1 viser et snit gennem en varmestrâlingsenhed i et glas-keramik-kogeapparat, 30 fig. 2 en isolerende bærer, fig. 3 den del, der i fig. 1 er omgivet af en cirkel III, i stort mâlforhold, 35 fig. 4 en variant af den i fig. 1 illustrerede fremstillings-metode, 3BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further explained in the following with reference to the drawing, in which FIG. 1 shows a section through a heat radiation unit in a glass-ceramic cooker. FIG. 2 shows an insulating carrier; FIG. 3 shows the part shown in FIG. 1 is surrounded by a circle III, in large dimensions, 35 fig. 4 shows a variant of the embodiment of FIG. 1 illustrated manufacturing method, 3

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fig'. 5 en varmeenhed, hvor der med stiplede linier er antydet en alternativ udformning, fig. δ den i fig. 5 viste varmeenhed, set i snit efter linien 5 VI-VI, fig. 7 den i fig. 5 viste varmeenhed, set i snit efter linien VII-VII, 10 fig. 8 et snit svarende til snitferingen i fig. 7 i stort mà 1 -forho 1d, fig. 9 en variant af den i fig. 6 viste snitf0ring, 15 fig. 10 en detalje af en anden udformning og fig. 11 et snit efter linien XI-XI i fig. 10 i stort màlfor-ho 1 d.FIG '. 5 shows a heating unit in which an alternate design is indicated by broken lines; FIG. δ the one in fig. 5 is a sectional view taken along line 5 VI-VI; FIG. 7 is the one shown in FIG. 5 is a sectional view taken along line VII-VII; FIG. 8 is a section similar to the sectional view of FIG. 7 in large measure 1-stage 1d, fig. 9 shows a variant of the embodiment shown in FIG. 6, FIG. 10 shows a detail of another embodiment and FIG. 11 is a sectional view taken along the line XI-XI of FIG. 10 in large measure-ho 1 d.

20 I fig. 1 er der vist en glaskeramikplade 11, der danner koge-fladen af et ikke vist elektrisk komfur. Under glaskeramikpla-den 11 er der anbragt en varmeenhed 12, der fortrinsvis er trykket mod undersiden af glaskerami kpladen 11 ved hjælp af ikke viste fjederelementer. Varmeenheden 12 har en bæreskâl 13 25 af plade bestàende af en nedre pladedel 14 i form af en flad skâl med jævn bund 16 og en evre pladedel 15 i form af en ring med Z-formet tværsnit. Pladedelene er forbundet indbyrdes ved deres mod hinanden liggende ringformede flanger.In FIG. 1 shows a glass ceramic plate 11 which forms the cooking surface of an electric cooker not shown. Under the glass ceramic plate 11 is arranged a heating unit 12, which is preferably pressed against the underside of the glass ceramic plate 11 by means of spring elements not shown. The heater unit 12 has a support bowl 13 25 of plate consisting of a lower plate portion 14 in the form of a flat bowl with a smooth bottom 16 and an outer plate portion 15 in the form of a ring of Z-shaped cross section. The plate members are interconnected by their annular annular flanges.

30 Bæreskâlen 13 er beklædt med isolerende materiale bestàende af to parallelt med bæreskâlens bund 16 liggende isolationslag eller -skiver 17, 18 samt en isolationsring 19. Disse isola tionslag kan være opbygget af flere materialer. Da varmeisola-tionsegenskaberne af hojtemperaturbestandige isolationsmateri-35 aler normalt aftager med stigende mekanisk styrke, kan der til isolationslagene 17, 18 anvendes et materiale med en forholds-vis ringe mekanisk styrke og gode varmeisolationsegenskaber, 430 The supporting shell 13 is coated with insulating material consisting of two insulating layers or discs 17, 18 lying parallel to the base of the supporting shell and an insulating ring 19. These insulating layers may be made up of several materials. Since the heat insulation properties of high temperature resistant insulating materials usually decrease with increasing mechanical strength, a material of relatively low mechanical strength and good thermal insulation properties can be used for the insulation layers 17, 18.

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eftersom isolationslagene i praksis ikke belastes særligt me-get. Det nedre lag 17 kan bestâ af et ikke eller kun svagt komprimeret beskyttelsesmateriale (eksempelvis tint fordelt kiselsyre) eller et materiale med en mindre varmebestandig-5 hed, eftersom dette sted er det "koldeste" af varmenheden.since in practice the insulation layers are not particularly stressed. The lower layer 17 may consist of a non-or only slightly compressed protective material (e.g., thinly distributed silicic acid) or a material with a less heat resistance, since this location is the "coldest" of the heating unit.

Derimod skal den isolerende underst0tningsring 19 hâve en noget hejere mekanisk styrke. Den kan f.eks. bestâ af et trævlet isolationsmateriale, eksempelvis af aluminiumoxidfibre, som under tilsætning af et passende bindemiddel sammenpresses til 10 dannelse af en papagtig struktur. Et sàdant materiale markeds-fsres under betegnelsen "Fiberfrax". André mineralske fibre kan dog ogsâ komme pâ taie.In contrast, the insulating support ring 19 must have a somewhat higher mechanical strength. It can e.g. consist of a wood-woven insulating material, for example aluminum oxide fibers, which, with the addition of a suitable binder, are compressed to form a cardboard-like structure. Such material is marketed under the term "Fiber Frax". However, other mineral fibers can also come in handy.

Pâ det .ovre iso 1 at ions 1 ag 18 og inde i isolationsr ingen 19 dog 15 indesluttet i en ringformet udskæring af isolationsringen, ligger der en isolerende bærer 20 i form af en cirkulær skive. Ved almindelige varmelegemer til et glaskeramikkomfur er ski-ven af storrelsesordenen 15 cm i diameter og 5 mm i tykkelse. Denne isolerende bærer 20 bestâr ligeledes af et presset trev-20 let isolationsmateriale med en meget hoj varmebestandighed og bærer pâ oversiden en efter en spiral forlobende og af trâd-spiraler bestâende varmemodstand 21, hvorved der tilvejebrin-ges et cirkulært varmeomrâde, hvor kun midterzonen 22 ikke er opvarmet.However, on the surface of ions 1 ag 18 and inside insulator 19, however, 15 enclosed in an annular cut of the insulation ring, there is an insulating support 20 in the form of a circular disc. In ordinary heaters for a glass ceramic stove, the disc is of the order of 15 cm in diameter and 5 mm in thickness. This insulating carrier 20 also consists of a pressed, lightweight insulating material with a very high heat resistance and carries on the upper side a heat resistance 21 which extends along a spiral and wire spirals, thereby providing a circular heat area where only the middle zone 22 not heated.

2525

Varmemodstandene 21 ligger over storstedelen af deres udstræk-ning pâ isolationsbærerens 20 overflade 23 eller en smule der-over. Fra den i det væsentlige plane overflade 23 er der nogle radiært udragende fremspring 24, 25. Fremspringene 24 forlober 30 fra yderranden til den uopvarmede midterzone 22, medens frem-springene 25 kun udstrækker sig ca. den halve vej. Afstandene imellem fremspringene ligger sâledes indenfor et bestemt om-râde. Fremspringene er fremstillet ved prægning af den isolerende bærer 20 under dennes fremstilling ved presning af den 35 med bindemiddel forsynede fibermasse. Derved indpresses varmemodstandene 21, sâledes at de gennemtrænger fremspringene 25 og fastholdes i disse. Som det fremgâr af fig. 2 og 3, er var- 5The heat resistors 21 lie over most of their extent on the surface 23 of the insulation carrier 20 or slightly above. From the substantially planar surface 23, there are some radially projecting projections 24, 25. The projections 24 extend from the outer edge to the unheated middle zone 22, while the projections 25 extend only approx. half way. Thus, the distances between the projections lie within a certain range. The projections are made by embossing the insulating support 20 during its manufacture by pressing the binder-bonded fiber pulp. Thereby the heat resistors 21 are pressed in such a way that they penetrate the projections 25 and are retained therein. As can be seen from FIG. 2 and 3, are 5

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memodstandene 21 i omrâdet af fremspringene 25 fortrinsvis indlejret med noget mere end halvdelen af deres omkreds, hvor-ved deres ovre bukning og nærmere bestemt næsten hele den ovre halvdel samt det indre af vindingen forbliver fri.the resistors 21 in the region of the projections 25 are preferably embedded with somewhat more than half of their circumference, whereby their upper bending and more nearly the entire upper half as well as the interior of the winding remain free.

55

Derved opnâs en ualmindelig god fastholdelse af varmemodstan-dene 21, uden at varmeudstrâlingen hæmmes. I omràdet mellem fremspringene 25 kan udstrâ1ingen fra varmemodstandene 21 uhindret finde sted, og i omrâdet ved fremspringene 25 er kun 10 udstrâlingen fra den nedre vindingsbue hæmmet. Derved tilveje-bringes et meget virksomt varmeelement med de bedste udstrâ-lingsforhold i opadgâende retning.Thereby, an exceptionally good retention of the heat resistances 21 is obtained without inhibiting the heat radiation. In the region between the projections 25, the radiating from the heat resistors 21 can occur unobstructed, and in the region of the projections 25 only the radiation from the lower winding arc is inhibited. This provides a very efficient heating element with the best radiating conditions in the upward direction.

Den isolerende bærer 20 kan ved et passende materialevalg el -15 1er ved en stærkere komprimer i ng af materialet fà en sterre mekanisk styrke end den evrige isolering. Den er derfor udfor-met som en skive, der dog altid har en papagtig struktur, og som er let at hândtere under fremsti11ing, montering og repe-ration. Varmemodstandene sidder sà godt fast pâ denne bærer, 20 at der ikke er risiko for, at de pâ en eller anden mâde fri-gores ved rystelser eller varmeudvidelser.The insulating support 20 can, by a suitable choice of material or -15, by a stronger compressor in the material, obtain a stronger mechanical strength than the eternal insulation. It is therefore designed as a disc, which always has a cardboard-like structure and which is easy to handle during manufacture, assembly and repair. The heat resistors are so firmly attached to this carrier that there is no risk that they will be released in some way by shaking or heat expansion.

Prægningen til dannelse af fremspringene 24, 25 giver anled- ning til, at der pâ isolationsbærerens underside dannes for-25 dybninger 26. Oversiden af det ovre isolationslag 18 kan lige-ledes være forsynet med indskæringer 27, sàledes at disse eventuelt krydsende indskæringer danner et hulrum til forbed-ring af isoleringen. Den elektriske tilslutning til spiralen fores fortrinsvis gennem isolationsbæreren nede fra, sàledes 30 at tilslutningslederne f.eks. kan forlobe i en af fordybnin-gerne 26. De tilsvarende ti1 s 1utningsstifter eller tunger kan under sammenpresningen trykkes gennem det endnu blode materia-le af iso1ationsbæreren. Isolationsbæreren udsættes efter sammenpresni ngen for en torrings- eller brændingsproces.The embossing to form the projections 24, 25 causes the holes 25 to be formed on the underside of the insulation carrier 26. The upper surface of the upper insulation layer 18 may also be provided with notches 27, so that these possibly intersecting cuts form a cavity for improving insulation. The electrical connection to the coil is preferably conducted downwards from the insulation carrier, such that the connection conductors, e.g. may extend in one of the recesses 26. The corresponding tenon pins or tongues may, during compression, be pressed through the still-bleed material of the insulation carrier. The insulation carrier is subjected to a drying or firing process after compression.

Varmeenheden monteres ved at isolations 1agene 17, 18 hældes ind i den nedre pladedel 14 eller indlægges, hvis det drejer 35 6The heating unit is mounted by pouring the insulating layers 17, 18 into the lower plate part 14 or inserting if it rotates.

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s ig om f orud pressede skiver, hvorefter isolationsbæreren 20 indlægges. Ti1 siutningslederne 28 fores ud til siden via en udskæring 29 i omràdet ved skillelinien mellem pladedelene 14 og 15. Derefter pâsættes isolationsringen 19, og varmeenheden 5 færdiggores ved pâsætning og fastgorelse af den ovre pladedel 15. Isolationsringen 19 har ogsâ en opdadvendt ringformet de! 30, der ligger an mod undersiden af g 1askeramikp1aden 11.apply pre-pressed discs, after which the insulation carrier 20 is inserted. The sealing conductors 28 are brought out to the side via a cut-out 29 in the area at the dividing line between the plate parts 14 and 15. The insulation ring 19 is then mounted and the heating unit 5 is completed by mounting and fixing the upper plate part 15. The insulation ring 19 also has an upwardly annular shape. 30, abutting the underside of the g ash ceramic plate 11.

I fig. 1 er der anvendt en temperaturbegrænser henholdsvis en 10 temperaturregulator 31 omfattende en stavformet temperaturfo-ler 31, der er fort diamentralt gennem strâlingsrummet 33 mellem varmemodstanden 21 og undersiden af glaskeramikpladen 11. Temperaturfoleren er fort gennem en âbning i pladedelen 15 og isolationsringen 19. Ved denne udformning mà temperaturfoleren 15 31 isoleres elektrisk som folge af, at der ogsâ kræves bero- ringssikkerhed i tilfælde af brud af glaskeramikpladen 11, hvilken isolering eksempelvis kan foretages ved overtrækning med et kvartsror. Af denne ârsag kan temperaturregulatoren 31 i udformningen i fig. 4, der i ovrigt er opbygget pâ samme 20 màde, vare sâledes anbragt, at den lige!edes gâr gennem skillelinien mellem de to pladedele 14 og 15 og ligger i indskæ-ringen i undersiden af iso1eringen 19 og pâ oversiden af i so-lationslaget 18. Ogsâ den isolerende bærer 20 har en diamen-tral indskæring 34 for temperaturfoleren 32, sâledes at denne 25 vil kunne affole opvarmningstemperaturen, eftersom den isolerende bærer pâ grund af den hojere mekaniske styrke og ringere termiske isolationsvirknirig meget hurtigt antager opvarmnings-temperaturen.In FIG. 1, a temperature limiter and a temperature regulator 31, respectively, comprising a rod-shaped temperature sensor 31 which is diametrically passed through the radiation space 33 between the heat resistance 21 and the underside of the glass ceramic plate 11, are used respectively. The temperature sensor is passed through an opening in the plate part 15 and the insulation ring 19. design, the temperature sensor 15 31 must be electrically insulated as a result of the fact that contact safety is also required in case of breakage of the glass ceramic plate 11, which can be done, for example, by coating with a quartz tube. For this reason, the temperature controller 31 of the embodiment of FIG. 4, which is otherwise constructed in the same way 20, is arranged so as to pass straight through the dividing line between the two plate parts 14 and 15 and lies in the notch in the underside of the insulation 19 and on the upper side of the insulation layer. 18. Also, the insulating support 20 has a diametrical cut-in 34 for the temperature sensor 32, so that it will be able to withstand the heating temperature since the insulating carrier, due to the higher mechanical strength and poor thermal insulation effect, very quickly adopts the heating temperature.

30 Ved denne udformning bliver strâlingsrummet 33 i stor udstræk-ning frigjort, og der kan indfores et jordforbundet gitter 35, sâledes at det hviler pâ en skulder af isoleringen 19', og kort under glaskeramikpladen 11 danner en beroringsbeskyttelse mod de under spænding stâende varmemodstande 21.30 In this embodiment, the radiation space 33 is largely freed, and a grounded grid 35 can be inserted to rest on a shoulder of the insulation 19 ', and shortly below the glass ceramic plate 11 provides a contact protection against the stressed heat resistances 21 .

0a den samlede isolation 17, 18, 19 og den isolerende bærer 20 kun skal komprimeres sâ meget, som det er pâkrævet af hensyn 35 70a the overall insulation 17, 18, 19 and the insulating carrier 20 must be compressed only to the extent required for

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tiTden mekaniske styrke, kan iso1ationsdelenes overflade ved ber0ring udvise nogen slitage. Af denne ârsag kan man behandle iso1ationsdelenes overflade ved f.eks. at oge tilsætningen af bindemiddel eller sprojte dern med en varmebestandig lak. Det 5 er endvidere fordelagtigt at forsyne isolationsbærerens over-side med en sort lak for derved at forbedre varmeudstrâlingen i opadgâende retning.Due to mechanical strength, the surface of the insulating members may exhibit wear on contact. For this reason, the surface of the insulating members can be treated by e.g. increasing the addition of binder or spray therewith with a heat-resistant varnish. It is further advantageous to provide the top side of the insulation carrier with a black lacquer so as to improve the heat radiation in the upward direction.

Varmeenheden er normalt cirkulær. Iso1ationsbæreren kan derfor 10 med fordel ogsà være cirkulær. Til opnâelse af en bedre t i 1 -pasning til den normale fire-anbringe1 se af kogeplader kan det imidlertid være en fordel at anvende firkantede eller kvadra-tiske varmeenheder. I dette tilfælde kan isolationsringen til overvindelse af en ydre firkantet og indre rund form hâve en 15 rund isolationsbærer.The heater is usually circular. Consequently, the insulation carrier 10 may advantageously also be circular. However, in order to obtain a better t in 1 fit to the normal four-plate of hobs, it may be advantageous to use square or square heating units. In this case, the insulation ring for overcoming an outer square and inner round shape may have a 15 round insulation support.

I tilfældet med en firkantet iso1ationsbærer henholdsvis iso-lationsring ved runde varmeringsomràder, kan der i overophe-dede hjorner være overvâgriings- eller affolingsanordninger til 20 overvâgning af temperaturen. Et styrtgodsagtigt isolationsma-teriale i omrâdet af iso1ations1agene 17, 18 til opnâelse af en stor varmeiso1ationsevne muliggores ved at anbringe varme-elementet pâ en mekanisk fast og forholdsvis tyk afslutnings-dannende isolationsbærer . Til andre netspændinger eller var-25 meeffekter mâ der kun fremstilles en anden isolationsbærer eller anvendes andre varmemodstande, medens de almindelige varmeenheder er uændrede og kan være seriefremsti1lede. Dette er ogsà muligt i forbindelse med lagring og reperation. Varmemod-standsspira 1 en kan udformes dobbelt svarende til, at begge en-30 derne ligger ved periferien, og de spira 1formede modstande danner to parallelle strenge, der forlober ind mod midten.In the case of a square insulation support or insulation ring at round heating areas, in overheated corners there may be overgrazing or unloading devices for monitoring the temperature. An impact-like insulating material in the area of the insulation layers 17, 18 to obtain a high thermal insulation capability is made possible by placing the heating element on a mechanically fixed and relatively thick end-forming insulation support. For other mains voltages or heat effects, only one other insulation carrier may be used or other heat resistors may be used, while the ordinary heating units are unchanged and may be series-produced. This is also possible in connection with storage and repair. The heat resistance coil 1 can be formed double corresponding to both ends lying at the periphery, and the coil 1 shaped resistors form two parallel strands extending towards the center.

Varmemodstandene pâ isolationsbæreren udgcres normalt af spi-raler, der er lagt i cirkelrunde trâdviklinger. Det kan dog 35 ogsà være fordelagtigt at gore trâdviklingen oval, nærmere be-stemt med den mindste udstrækning i retning af glaskeramik-pladen. Derved kan strâ1ingsrummet ogsâ ved storre viklingerThe heat resistors on the insulation carrier are usually formed by spirals placed in circular thread windings. However, it may also be advantageous to make the wire winding oval, more precisely with the smallest extent in the direction of the glass ceramic plate. In this way, the radiation space can also with larger windings

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8 fâ en betydelig storrelse, hvilket under visse omstændigheder er nodvendigt af hensyn til gennems1agsstyrken. Det er dog al-tid vanskeligt trods god isolation og fornaden gennems1ags-styrke at fremstille varmeenheden i en ringe tykkelse, samti-5 digt med at varmeenheden pâ undersiden har en lav temperatur af hensyn til éventuelle tilstadede brændbare dele.8 of considerable size, which is necessary in certain circumstances for the sake of average strength. However, it is always difficult, despite good insulation and the required average strength, to produce the heating unit at a small thickness, while at the lower side the heating unit has a low temperature for any combustible parts present.

I en yderligere ikke vist variant kan spiralen enkelte steder være anbragt noget dybere i iso1ationsbæreren, eksempelvis for 10 at give plads for en stavformet temperaturfaler. Ved denne fordybning kan den nadvendige isolatoinsafstand opnâs, uden at hele strâîingsfladen ligger dybere.In a further variant not shown, the coil may in some places be positioned somewhat deeper in the insulation carrier, for example to allow for a rod-shaped temperature sensor. At this recess, the required isolatoin distance can be obtained without the entire radiation surface being deeper.

I det beskrevne udfare!seseksempel har hver varmeenhed en sær-15 lig bæreskâl, der er pâtrykt pâ g 1 askeramikp 1 aden . Ved et af flere enheder bestâende kogeapparat er det dog ogsâ muligt at najes med én bæreskâl, i hvilken der ligger en isolering, der afgrænser skâlforinenes indskæringer til optagelse af isola-t i onsbæreren.In the disclosed example, each heating unit has a separate support shell printed on 1 ash ceramic package. However, with one cooker consisting of several units, it is also possible to sew with one support bowl, in which there is an insulation, which delimits the cut-outs of the shell liners to accommodate isolation in the onion carrier.

2020

Den i fig. 5-9 viste varmeenhed 111 har en isolationsbærer 112 med en firkantet form og fortrinsvis en kvadratisk flad skâl med en bund 113 og kanter 114, der er fremstillet af isola-tionsmateriale, eksempelvis et ved presning formet og ved 25 hjælp af bindemiddel fastgjort fiberagtigt isolationsmateriale.The FIG. 5-9, heating unit 111 has an insulating support 112 of a square shape and preferably a square flat shell with a bottom 113 and edges 114 made of insulating material, for example a compression-molded fibrous insulating material formed by means of binder. .

Den mod skâlens indre 116 vendende side 115 af bunden 113 er s i k-sak-f ormet, sâledes som det især fremgâr af fig. 7 og 8.The side 115 of the bottom 113 facing the shell 116 of the shell 113 is s in the k-sak shape, as is particularly apparent from FIG. 7 and 8.

30 Den bestâr af parallelt forlabende balgeformede fremspring og forsænkninger, hvoraf toppunktet 117 er forholdsvis skarpt.30 It consists of parallel extending bellows projections and recesses, of which the apex 117 is relatively sharp.

Sik-sak-formen er forholdsvis flad.The zig-zag shape is relatively flat.

I inderrummet 116 og pâ overf1aden 115 er der en varmemodstand 35 118 bestâende af en balgeformet frem- og ti1bagegâende mod- standstrâd, idet pâ hinanden falgende afsnit 119 af varmemod-standene forlaber frem og tilbage ved siden af hinanden. De er 9In the interior space 116 and on the surface 115 there is a heat resistance 35 118 consisting of a bellows-shaped reciprocating resistance wire, with successive sections 119 of the heating resistors advancing back and forth side by side. They are 9

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forbundet indbyrdes via U-formede omrâder 120, der eksempe1vis ved "trækning" (g 1astrækning) af den opvarmede vikling er ud-formet i det væsentlige som en glat og uviklet trâd. Disse forbinde1sesomrâder 120 er indlejret i forhojninger 121 af 5 isolat ionsbæreren, dvs. fortrinsvis indpresset inden isola-tionsbæreren haerdes. Forhojningerne kan hâve form som en eller flere sik-sak-formede bslger, sàledes at det indlejrede omrâde trods vidtgâende fastg0relse er indskrænket til et minimum.are interconnected via U-shaped regions 120, which, for example, by "pulling" (g 1 stretching) the heated winding is formed essentially as a smooth and unwinding thread. These connection areas 120 are embedded in elevations 121 of the insulation carrier, i.e. preferably pressed before curing the insulating support. The elevations may take the form of one or more zigzag-shaped beetles, so that the embedded area is minimized despite extensive fixation.

10 Det ses at udstrækningen af de sik-sak-formede forhojninger 121 og de derimellem liggende fordybninger 122 forlofoer pâ tværs af udstrækningen af varmemodstandsafsnittene 119. Det fremgâr af fig. 8, at varmemodstandene i omràdet af toppunk-terne 117 er indlejret med fortrinsvis kun én og i aile til-15 fælde kum fâ vindinger ved indpresning inden hærdningen. Der-ved er af hver vinding kun en ringe de! af den mod overfladen 115 vendende deT indlejret, medens den 0vrige del af vindingen 1 igger fri.10 It is seen that the extent of the zigzag-shaped elevations 121 and the recesses 122 lying there transverse the extension of the heat resistance sections 119. It can be seen from FIG. 8, that the heat resistors in the region of the apexes 117 are embedded with preferably only one and in all cases cum turns in compression prior to curing. Thereby, of every winnings, there is only one poor one! of the deT facing the surface 115 embedded while the other part of the winding 1 is free.

20 Fig. 9 viser en variant, hvor der pâ tværs af forhejningen 121' og fordybningen 122' yderligere er indlejret en vinding, sâledes at varmeviklingen er indlejret i en ved forhajninger-nes skæringspunkter dannet spids 123.FIG. 9 shows a variant in which a winding is further embedded across the elevation 121 'and the recess 122' so that the heat winding is embedded in a tip 123 formed at the intersections of the elevations.

25 Ved denne foranstaltning er varmeviklingen trods vidtgâende fastgorelse til i so 1 at i onsbeereren, der danner en let monterbar enhed, kun indlejret i et lille omrâde, sâledes at faren for lokal overophedning med risiko for gennembrænding er elimine-ret. Dertil bidrager ogsâ den omstændighed, at spiralen under 30 udvidelse tilpassses til den sik-sak-formede overflade, og derved ligger pâ overfladen, uden at der ved stodpâvirkninger sker en udbojning til siden. Hele varmeviklingens overside er fri, og udstràling vil derfor frit kunne finde sted. Den mean-derformede udformning muliggor en ret god procentuel varmefla-35 debelægning, hvortil kommer, at varmeviklingerne kan ligge forholdsvis tæt, dels som folge af den sik-sak-formede udformning, og dels som folge af at udbojningerne til siden forhin- 1025 By this measure, the thermal winding, despite extensive fixing, is that in the sole carrier forming an easily assembled unit is only embedded in a small area, so that the danger of local overheating with the risk of burnout is eliminated. In addition, the coil contributes to the zigzag-shaped surface during the extension, and thereby lies on the surface, without sideways deflection. The entire surface of the heat exchanger is free, and radiation can therefore freely take place. The mean-shaped configuration allows for a fairly good percentage of heat-surface coating, in addition to which the heat windings can be relatively dense, partly as a result of the zig-zag-shaped design and partly as a result of the lateral projections being prevented.

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dres, hvorved risikoen for kortslutning reduceres. Dertil kom-mer, at en eventuel kortslutning ikke fâr store folger, efter-som spændingsforskellen mellem to enkelte afsnit 119 er meget Tille.is reduced, thereby reducing the risk of short-circuiting. In addition, a possible short circuit will not have major consequences, as the voltage difference between two individual sections 119 is very low.

5 I forbindelsesomràderne 120 afgives der kun lidt varmeenergi, eftersom der anvendes ikke-viklet tràd. Dette er særlig vig-tigt, da der ved U-bojningerne er fare for varmeophobni ng, hvorfor en fastgorelse ved indlejring vil være nodvendig.5 In the connection areas 120, only a little heat energy is emitted, since non-wound thread is used. This is particularly important, as there is a risk of heat buildup at the U-bends, so a fixing on embedding will be necessary.

10 Pâ begge sider af de ydre varmemodstandsafsnit 119 ligger der temperaturfolere 125 af temperaturkoblingsorganer 126; enten i form af en temperaturbegrænser eller en temperaturregulator.On both sides of the outer heat resistance sections 119 there are temperature sensors 125 of temperature coupling means 126; either in the form of a temperature limiter or a temperature controller.

Det kan her dreje sig om en stavformet temperatur fol er be-15 stâende af en udvide!sesbælg og en deri liggende stav, der kun udvider sig forholdsvis lidt, hvilken foler udstrækker sig over hele isolationsbærerens indre kant og forlober i varmemod-standens plan mellem randen 114 og langs det ydre afsnit 119.Here it can be a rod-shaped temperature consisting of an expanding bellows and a rod extending therein only a little, extending over the entire inner edge of the insulation carrier and extending in the plane of the heat resistance between the rim 114 and along the outer section 119.

Den gâr gennem en udskæring 127 i randen 114, sâledes at ho~ 20 vedet, der bærer en omskifter, stikker uden for det opvarmede omrâde. Varmemodstandens 118 tilslutninger er ogsâ fort gennem dette omrâde, hvilke tilslutninger umiddelbart kan tilsluttes til omskifterhovedets tilslutning, sâledes at dette samtidigt danner tilslutningsdelen for varmemodstanden. I en temperatur-25 foleranordning er begge tilslutninger foretaget pâ begge sider ved hjælp af tiIslutningsorganerne, sâledes at særlige til-s1utningsdele ikke er nodvendige. Temperaturomskifterorganerne er dermed forbundet i sérié med varmemodstande, sâledes at varmemodstanden 118 vil kunne udkobles ved en temperaturfolers 30 me 11emkomst.It passes through a cutout 127 in the rim 114, such that the high wood carrying a switch protrudes outside the heated area. The connections of the heat resistance 118 are also fast through this area, which connections can be immediately connected to the connection of the switch head, so that this simultaneously forms the connection part for the heat resistance. In a temperature sensing device, both connections are made on both sides by means of the connecting means, so that no special connection parts are necessary. The temperature switching means are thus connected in series with heat resistors, so that the heat resistance 118 can be switched off at a temperature sensor 30 meters.

I fig. 5 og 6 er der vist et temperaturomski fterorgan 126', der kan være udformet pâ samme màde som tidligere beskrevet.In FIG. 5 and 6 there is shown a temperature switching means 126 'which may be designed in the same manner as previously described.

Den respektive temperaturfoler 125' ligger noget under varme-35 modstandenes plan i en fordybning 128 af isolationsbæreren og gennembryder ribberne 121. Ogsâ her er temperaturfoleren an-bragt parallelt med afsnittene 119, og nærmere bestemt i umid- 11The respective temperature foil 125 'lies somewhat below the plane of the heat resistors in a recess 128 of the insulation carrier and pierces the ribs 121. Here, too, the temperature sensor is arranged parallel to the sections 119, and more particularly in

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delbar nærhed af to afstvit, sàledes at den har et gunstigt greb i varmemodstandenes temperatur. Temperaturanordningen pa-rallelt med varmemodstandene sorger for en effektiv regulering og begrænsning af temperaturen, og overtemperaturer i glaske-5 ramikpladen undgâs. Man undgâr derved, at der under tempera-turmodstandenes temperaturforleb og derved i glaskeramikmate-rialet opstàr temperaturer, der kan fore til beskadigelse af glaskeramikoverfladen. Opvarmningen kan ogsâ ske ved en hejere middelværdi, hvorved effektgennemgangen forbedres yderligere.divisible proximity of two offset so that it has a favorable grip on the temperature of the heat resistance. The temperature device parallel to the heat resistors provides for effective control and limitation of the temperature, and overtemperatures in the glass ceramic plate are avoided. In this way, it is avoided that during the temperature resistance of the temperature resistors and thereby in the glass ceramic material, temperatures are created which can lead to damage to the glass ceramic surface. The heating can also be done at a higher mean, which further improves the power output.

1010

Varmeenheden 111'.i fig. 10 svarer med hensyn til isolatîons-bærerens udformning og med hensyn til udformningen og anbrin-gelsen af varmemodstandene til udformningen i fig. 5. Tempera-turomskifterorganet 126a er blot anbragt pâ en anden mâde. Den 15 tilhorende temperaturfizrl er 125a, der ligeledes er en stavfor-met foler, ligger som vist i fig. 11 i en dyb udskæring 130 i isolationsbærerens 112a bund 113a. Udskærîngen og dermed tem-peraturfoleren 125a forlober pâ tværs af de enkelte afsnit 119 af varmemodstandene 118. Eftersom foleren 125a ligger for-20 holdsvis tæt under varmemodstandene, er udskæringen 130 for- synet med en afdækning 131 i form af en kvartsskive. Det er ogsâ her muligt at forsyne foleren med en belægning af et hoj-temperaturbestandigt isolerende, men alligevel strâ1ingsgen-nemtrængeligt materiale.The heating unit 111'.in fig. 10 corresponds to the design of the insulating carrier and to the design and application of the heat resistors to the configuration of FIG. 5. The temperature switching means 126a is merely arranged in a different way. The associated temperature fi gure is 125a, which is also a rod-shaped foil, as shown in Figs. 11 in a deep cut 130 in the bottom 113a of the insulation carrier 112a. The cutout and thus the temperature foil 125a extends across the individual sections 119 of the heat resistors 118. Since the foil 125a is relatively close to the heat resistors, the cut 130 is provided with a cover 131 in the form of a quartz disc. Here it is also possible to provide the foil with a coating of a high-temperature resistant insulating, yet radiation-permeable material.

2525

De beskrevne udforelseseksempler vil kunne varieres pâ flere forskellige mâder. F.eks. kan der anvendes en sik-sak-formet form, hvor der i omrâdet mellem fordybningerne 122 er et fladt stykke. Ved modstandenes fastgærelse skal det frem for ait 30 sikres, at toppunkterne er forholdsvis spidse, hvorved det indlejrede omràde af varmeviklingen bliver forholdsvis lille.The embodiments described may be varied in several ways. Eg. For example, a zigzag-shaped shape may be used, in which in the area between the recesses 122 is a flat piece. In fixing the resistors, it must be ensured, rather than ait 30, that the apexes are relatively pointed, whereby the embedded area of the heat winding becomes relatively small.

I stedet for som beskrevet til opvarmning af en glaskeramikko-geplade, kan varmeenheden ogsâ indrettes til opvarmning af an-dre genstande, f.eks. i industriovne til opvarmning af metal-35 plader eller -vægge, eller til opvarmning af kar.Instead of as described for heating a glass ceramic hob, the heating unit can also be arranged for heating other objects, e.g. in industrial furnaces for heating metal plates or walls, or for heating vessels.

Forseg har vist, at der ogsâ opnâs en udmærket fastgorelse og gode udstrâlingsegenskaber, hvis varmespira1 en ikke kun erForseg has shown that excellent fixation and good radiating properties are also obtained, if the heat sink is not only

Claims (3)

5 Patentkrav.5 Patent claims. 1. Fremgangsmâde til fremsti11ing af et elektrisk varmestrâ-1ingselement, ved hvilken fremgangsmâde en som tràdspiral ud- 10 formet varmemodstand (21, 118) nedsænkes i et fiberholdigt isolerende mater i ale indeholdende en isolerende bærer (20, 112), der derefter hærdes eller t0rres, kendetegnet ved, at trâdspiralen over en de! af sin h0jde indtrykkes i en forberedt plastisk deformerbar isolerende bærer (20, 112) med 15 en i det væsentlige pladeformet overflade og i en sàdan grad, at det isolerende materiale kun i mindre mængde tranger ind i me 11emrummene mellem vindingerne af trâdspiralen, og i vid ud-strækning kun omslutter trâdene og i vid udstrækning frilægger det frie indre af trâdspiralen fra isolationsmaterialet. 20A method of producing an electric heat radiation element, wherein a method of wire-shaped heat resistance (21, 118) is immersed in a fiber-containing insulating material in ale containing an insulating support (20, 112) which is then cured or dried, characterized by the threading coil over a de! of its height, is pressed into a prepared plastic deformable insulating carrier (20, 112) having a substantially plate-shaped surface and to such an extent that the insulating material penetrates only to a lesser extent between the windings of the wire coil, and in to a large extent, the wires only enclose and to a large extent expose the free interior of the wire coil from the insulation material. 20 2. Fremgangsmâde if0lge krav 1, kendetegnet ved, at indtrykningen foretages under presningen af isolationsbæreren (20, 112).Method according to claim 1, characterized in that the impression is made during the pressing of the insulation carrier (20, 112). 3. Fremgangsmâde ifolge ethvert af de foregâende krav, k e n d e t e g n e t ved, at kun en lille de! af tràdspira-lens vinding indlejres, medens det evrige omrâde af spiralens periferi holdes fri. 30 353. A method according to any of the preceding claims, wherein only a small de! of the wire coil winding is embedded while keeping the eternal area of the spiral periphery. 30 35