ITVI970050A1 - MUFFLE TO CARRY OUT HEAT TREATMENTS - Google Patents
MUFFLE TO CARRY OUT HEAT TREATMENTS Download PDFInfo
- Publication number
- ITVI970050A1 ITVI970050A1 IT97VI000050A ITVI970050A ITVI970050A1 IT VI970050 A1 ITVI970050 A1 IT VI970050A1 IT 97VI000050 A IT97VI000050 A IT 97VI000050A IT VI970050 A ITVI970050 A IT VI970050A IT VI970050 A1 ITVI970050 A1 IT VI970050A1
- Authority
- IT
- Italy
- Prior art keywords
- muffle
- stainless steel
- silicon carbide
- ceramic material
- conveyor belt
- Prior art date
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- 238000011282 treatment Methods 0.000 title description 2
- 238000010438 heat treatment Methods 0.000 claims description 16
- 229910001220 stainless steel Inorganic materials 0.000 claims description 15
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 14
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 14
- 239000010935 stainless steel Substances 0.000 claims description 14
- 229910010293 ceramic material Inorganic materials 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 230000003068 static effect Effects 0.000 claims description 4
- 238000005496 tempering Methods 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims description 4
- 239000000919 ceramic Substances 0.000 claims description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 2
- 229910045601 alloy Inorganic materials 0.000 claims description 2
- 239000000956 alloy Substances 0.000 claims description 2
- 238000000137 annealing Methods 0.000 claims description 2
- 238000005219 brazing Methods 0.000 claims description 2
- 238000001035 drying Methods 0.000 claims description 2
- 238000010304 firing Methods 0.000 claims description 2
- 229910001092 metal group alloy Inorganic materials 0.000 claims description 2
- 239000010970 precious metal Substances 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 claims description 2
- 239000010703 silicon Substances 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- 239000004332 silver Substances 0.000 claims description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims 2
- 229910001020 Au alloy Inorganic materials 0.000 claims 1
- 239000003353 gold alloy Substances 0.000 claims 1
- 239000003208 petroleum Substances 0.000 claims 1
- 229910052697 platinum Inorganic materials 0.000 claims 1
- 239000000463 material Substances 0.000 description 7
- 238000012545 processing Methods 0.000 description 4
- 230000002035 prolonged effect Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000035939 shock Effects 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000009533 lab test Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 230000000284 resting effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910001260 Pt alloy Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000004320 controlled atmosphere Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000008246 gaseous mixture Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0043—Muffle furnaces; Retort furnaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/06—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated
- F27B9/062—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated electrically heated
- F27B9/063—Resistor heating, e.g. with resistors also emitting IR rays
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/06—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated
- F27B9/08—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated heated through chamber walls
- F27B9/082—Muffle furnaces
- F27B9/084—Muffle furnaces the muffle being fixed and in a single piece
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
- F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace
- F27B9/24—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace being carried by a conveyor
- F27B9/243—Endless-strand conveyor
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Thermal Sciences (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Tunnel Furnaces (AREA)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
Description
Descr i z ione Description
Il trovato riguarda una muffola per eseguire trattamenti termici, secondo la parte generale della rivendicazione 1. The invention relates to a muffle for performing heat treatments, according to the general part of claim 1.
Quando un materiale metallico viene sottoposto a lavorazione meccanica, in modo particolare se a freddo, esso è soggetto al ben noto fenomeno dell'incrudimento, derivante dalla deformazione della disposizione cristallografica del reticolo che rende il materiale lavorato più duro e più fragile e tale da non prestarsi in modo ottimale alle eventuali successive lavorazioni quali la formatura, la piegatura ed altre ancora. When a metal material is subjected to mechanical processing, particularly if cold, it is subject to the well-known phenomenon of hardening, deriving from the deformation of the crystallographic arrangement of the lattice which makes the processed material harder and more fragile and such as not to lend themselves optimally to any subsequent processing such as forming, bending and others.
11 prodotto lavorato ed incrudito deve quindi essere sottoposto al trattamento di processi quali la rico ttura;med iante la quale si provvede alla ricostruzione dell’originale reticolo cr istallino conferendo al materiale stesso le caratteristiche di duttilità, malleabilità e le altre-proprietà meccaniche e fisiche possedute in origine e necessarie, per poter subire le successive lavorazioni. The worked and work hardened product must therefore be subjected to the treatment of processes such as coating; by means of which the original crystal lattice is reconstructed, giving the material itself the characteristics of ductility, malleability and other mechanical and physical properties. originally owned and necessary, in order to undergo subsequent processing.
La ricottura consiste in un trattamento termico prolungato, ad una temperatura elevata, ma inferiore a quella di rammollimento, con successivo lento o istantaneo raffreddamento, in modo da eliminare le tensioni interne. Annealing consists of a prolonged heat treatment, at a high temperature, but lower than the softening one, with subsequent slow or instant cooling, in order to eliminate internal tensions.
Altri processi industriali prevedono l'impiego di un trattamento termico prolungato come, ad esempio, le lavorazioni industriali di saldobrasatura, la saldatura, il rinvenimento, la bonifica, la tempra, l'asciugatura, la cementazione, la cottura di prodotti ceramici ed altre. Other industrial processes involve the use of a prolonged heat treatment such as, for example, industrial braze welding, welding, tempering, tempering, tempering, drying, cementation, firing of ceramic products and others.
Per attuare i trattamenti termici prolungati nelle lavorazioni succitate viene impiegata un’attrezzatura denominata muffola e costituita essenzialmente dalla camera di un fórno in cui il materiale da trattare è tenuto separato dalla fonte di calore, costituita da combustìbile solido, liquido, gassoso, da resistor! elettrici o da sorgenti di induzione elettromagnetica. To carry out the prolonged heat treatments in the aforementioned processes, an equipment called a muffle is used and essentially consists of the chamber of a furnace in which the material to be treated is kept separate from the heat source, consisting of solid, liquid, gaseous fuel, by resistor! electrical or electromagnetic induction sources.
Il riscaldamento della muffola avviene quindi indirettamente per irraggiamento e convezione. The heating of the muffle therefore takes place indirectly by radiation and convection.
Operativamente, per attuare il trattamento termico sopra citato il prodotto viene fatto passare in continuo o posto staticamente in muffole di riscaldamento, che vengono poste all'interno di forni coibentati e riscaldate indirettamente per convezione ed irraggiamento, tramite l’energia fornita da circuiti elettrici a resistenza o ad induzione, posti all'esterna della muffola stessa o a mezzo di miscela gassosa combustibile, fuoriuscente da bruciatori a propano o metano, che fluisce entro tubi radianti<” >anch'essi posti esternamente e perimetralmente rispetto alla muffola suddetta. Operationally, to carry out the aforementioned heat treatment, the product is passed continuously or statically placed in heating muffles, which are placed inside insulated ovens and heated indirectly by convection and radiation, through the energy supplied by electrical circuits. resistance or induction, placed outside the muffle itself or by means of a combustible gaseous mixture, coming out of propane or methane burners, which flows inside radiant tubes <”> also placed externally and perimetrically with respect to the aforementioned muffle.
In particolare per eseguire trattamenti termici prolungati in forni a ciclo continuo o statici, eventualmente con atmosfera controllata, di fili, nastri piattine, catename, lingotti, oggettistica, particolari in leghe di oro, argento, platino e leghe preziose in genere, nonché acciai inossidabili ed altre leghe metalliche utilizzate nel campo de ll'oreficer ie, orologeria, bigiotteria ed industria del metallo prezioso in genere, vengono impiegate delle muffole di forma parailelepipeidale, allungata in senso orizzontale, che delimita una camera riscaldata tramite dei resistori annegati nella porzione refrattaria del corpo del.forno o poste esternamente rispetto alla muffola stessa. In particular to perform prolonged heat treatments in continuous cycle or static ovens, possibly with controlled atmosphere, of wires, flat ribbons, chains, ingots, objects, details in gold, silver, platinum alloys and precious alloys in general, as well as stainless steels and other metal alloys used in the field of goldsmiths, watchmaking, costume jewelery and the precious metal industry in general, horizontally elongated parailelepipeidal flasks are used, which delimits a heated chamber by means of resistors embedded in the refractory portion of the furnace body or placed outside the muffle itself.
Allo stato attuale della tecnica le muffole sono realizzate in acciaio inox refrattario. In the current state of the art, the muffles are made of refractory stainless steel.
A fronte di un buon coefficiente di trasmissione termica l'utilizzo dell’acciaio inox refrattario per le costruzione di muffole presenta altresì anche numerosi inconvenienti, dipendenti specificatamente dalle particolari condizioni di lavoro a cui è sottoposta la muffola. In the face of a good heat transmission coefficient, the use of refractory stainless steel for the construction of muffles also has numerous drawbacks, depending specifically on the particular working conditions to which the muffle is subjected.
Infatti, dopo un certo periodo di lavoro le muffole costruite in acciaio inox refrattario sono soggette a fenomeni di ossidazione e sfogliatura del materiale metallico ed alla deformazione strutturale del corpo, con ben immaginabili conseguenze negative di tipo economico/ poichè ciò comporta l'arresto della macchina e la necessità di svolgere una operazione di manutenzione per la riparazione e o la sostituzione della muffola stessa. In fact, after a certain period of work, the muffles made of refractory stainless steel are subject to oxidation and flaking phenomena of the metal material and to structural deformation of the body, with well-conceivable negative economic consequences / as this involves stopping the machine. and the need to carry out a maintenance operation for the repair and or replacement of the muffle itself.
In dettaglio, l'ossidazione e la successiva sfogliatura dell'acciaio inox, costituente il corpo della muffola, è conseguente all'azione corrosiva degli additivi in polvere che vengono impiegati nei procedimenti di saldatura e sa 1dobrasatura degli oggetti contenuti nella muffola, nonché da altri componenti chimici impiegati nei trattamenti termici precedentemente subiti dagli oggetti medesimi. In detail, the oxidation and subsequent peeling of the stainless steel, which constitutes the body of the muffle, is a consequence of the corrosive action of the powder additives that are used in the welding and brazing processes of the objects contained in the muffle, as well as by other chemical components used in the heat treatments previously undergone by the objects themselves.
Tale fenomeno è così forte che nemmeno l'impiego di atmosfere controllate, protettive e disossidanti, immesse all'interno della muffola, riescono ad eliminare tale azione di corrosione del materiale, anche se contribuiscono a rallentarla. This phenomenon is so strong that not even the use of controlled, protective and deoxidizing atmospheres, placed inside the muffle, is able to eliminate this corrosion action of the material, even if they contribute to slowing it down.
L'inconveniente della deformazione strutturale, che può svilupparsi fino ad arrivare allo svergolamento del corpo della muffola, conseguente allo sbalzo termico che si genera fra le diverse zone del corpo metallico stesso, determina il fenomeno cosiddetto della "squamatura" del l ' acciaio per cui delle minuscole particelle metalliche vanno a porsi al di sopra di resistori ,determinando un cattivo funzionamento degli stessi e quindi un processo di riscaldamento non regolare. The drawback of the structural deformation, which can develop up to the warping of the muffle body, consequent to the thermal shock that is generated between the different areas of the metal body itself, determines the so-called "flaking" phenomenon of the steel for which of the tiny metal particles are placed above resistors, causing a malfunction of the same and therefore an irregular heating process.
In particolare, l'effetto dello sbalzo termico è notevole nei forni continui dove il nastro trasportatore, a maglia metallica, su cui sono depositati gli oggetti da riscaldare, percorre per l'intera lunghezza la camera della muffola. In particular, the effect of the thermal shock is considerable in continuous furnaces where the conveyor belt, with metal mesh, on which the objects to be heated are deposited, runs along the entire length of the muffle chamber.
In tale situazione;qu indi, lo sbalzo termico nella direzione longitudinale corrispondente alla direzione di avanzamento del nastra, è notevole,poichè è presente un continuo movimento di entrata nella muffola di pezzi da trattare che sono a temperatura ambiente, mentre l'interno della muffola ha una temperatura che può superare i 1100°C. In this situation; therefore, the thermal shock in the longitudinal direction corresponding to the direction of advancement of the belt is considerable, as there is a continuous movement of pieces to be treated entering the muffle which are at room temperature, while the inside of the muffle it has a temperature that can exceed 1100 ° C.
Alla deformazione del corpo metallico della muffola nella direzione longitudinale, dipendente dal fatto che si introducono pezzi a temperatura ambiente (freddi) ed escono pezzi molto caldi, si aggiunge anche una deformazione trasversale, cioè della sezione del corpo, dovuta al fatto che esiste sempre una differenza di temperatura fra la base ed il cielo della muf fola favorita dal nastro di trasporto che, dovendo rimanere perfettamente piano, scorre appoggiato sulla base della camera. To the deformation of the metal body of the muffle in the longitudinal direction, which depends on the fact that pieces are introduced at room temperature (cold) and very hot pieces come out, there is also a transversal deformation, i.e. of the section of the body, due to the fact that there is always a temperature difference between the base and the top of the muf fola favored by the conveyor belt which, having to remain perfectly flat, slides resting on the base of the chamber.
Scopo del trovato è quello di realizzare una muffola che elimini gli inconvenienti sopra citati. The object of the invention is to provide a muffle which eliminates the aforementioned drawbacks.
Prove di laboratorio ed esperiménti su forni funzionanti a diverse temperature hanno evidenziato come sia soddisfacente l'impiego di una muffola realizzata con un impasto a base di materiale ceramico e tra i diversi tipi di tale materiale il più vantaggioso é risultato il carburo di silicio, con una percentuale di silicio variante fra 82'/·- 88*/.. Laboratory tests and experiments on furnaces operating at different temperatures have shown how satisfactory the use of a muffle made with a mixture based on ceramic material is satisfactory and among the different types of this material the most advantageous is silicon carbide, with a percentage of silicon varying between 82 '/ - 88 * / ..
Tale impasto ceramico, oltre ad una ottima conducibilità termica ed alla facilità di lavorazione, per stampaggio o per colata, grazie alle proprietà chimiche dei suoi componenti risulta perfettamente stabile agli sbalzi improvvisi di temperatura, anche di elevato valore e totalmente inattaccabile dai gas e fumi che sì sprigionano nella camera durante il trattamento termico di riscaldamento. This ceramic mixture, in addition to excellent thermal conductivity and ease of processing, by molding or casting, thanks to the chemical properties of its components is perfectly stable to sudden changes in temperature, even of high value and totally unassailable by gases and fumes that they are released into the chamber during the heating heat treatment.
Con ciò si realizzano delle muffole dove la stabilità del materiale e l'indeformabilità della camera rendono meno frequenti le onerose operazioni di manutenzione periodica del forno ed il 'nastro di trasporto può scorrere nelle condizioni ottimali, ossia appoggiato sulla base della suddetta camera. With this, muffles are created where the stability of the material and the non-deformability of the chamber make the onerous operations of periodic maintenance of the furnace less frequent and the conveyor belt can run in optimal conditions, that is resting on the base of the aforementioned chamber.
L'impiego del Carburo di Silicio quale materiale per costituire il corpo della muffola permette inoltre di eliminare l'utilizzo della gabbia di supporto dei resistori, prevedendo, vantaggiosamente, che questi ultimi siano immersi entro lo spessore del suddetto corpo; ciò è possibile per la ottima conducibilità termina del carburo di silicio. The use of Silicon Carbide as a material for constituting the body of the muffle also allows to eliminate the use of the cage supporting the resistors, advantageously providing that the latter are immersed within the thickness of the aforesaid body; this is possible due to the excellent termination conductivity of the silicon carbide.
Quando le temperature di lavoro non sono troppo elevate, il trovato prevede che solamente la parte inferiore della muffola venga realizzata in carburo di silìcio mentre la parte superiore, meno soggetta agli sbalzi termici, può rimanere costruita in acciaio inox refrattario, come d'uso, con evidenti risparmi di tipo economico . When the working temperatures are not too high, the invention provides that only the lower part of the muffle is made of silicon carbide while the upper part, less subject to thermal changes, can remain made of refractory stainless steel, as usual. with obvious economic savings.
Infine, sempre per motivi economici e per poter utilizzare le muffole esistenti in acciaio, il trovato prevede che venga realizzata in carburo di silicio solo una base, che va ad interporsi fra il piano inferiore della muffola, in acciaio inox refrattario, ed il nastro di trasporto sul quale sono posti i pezzi da risca ldare. Finally, again for economic reasons and to be able to use the existing steel muffles, the invention provides that only one base is made of silicon carbide, which is to be interposed between the lower surface of the muffle, in refractory stainless steel, and the transport on which the pieces to be heated are placed.
Queste ed altre caratteristiche del trovato verranno maggiormente evidenziate mediante la descrizione di una sua possibile forma di realizzazione, resa a solo titolo di esempio illustrativo e non limitativo, con l'aiuto delle tavole di disegno allegate dove: These and other characteristics of the invention will be better highlighted by the description of a possible embodiment thereof, given only by way of illustrative and non-limiting example, with the help of the attached drawing tables where:
- la fig. 1 rappresenta una vista in elevazione - fig. 1 represents an elevation view
ed in sezione della muffola di cui al trovato. and in section of the muffle according to the invention.
- la fig. 2 rappresenta una vista trasversale, sezionata secondo la linea II—II di fig.l, del la muffola; - fig. 2 represents a transversal view, sectioned along the line II-II of fig. 1, of the muffle;
- la fig. 3 rappresenta una vista trasversale sezionata, in una seconda possibile forma di reai izzazione; - fig. 3 represents a cross sectional view, in a second possible embodiment;
- la fig. ^ rappresenta una vista trasversale sezionata, con la muffola di acciaio/carburo di silicio; - fig. ^ represents a cross sectional view, with the steel / silicon carbide muffle;
- la fig. 5 rappresenta una vista trasversale sezionata, con muffola in acciaio inox refrattario e base in carburo di silicio. - fig. 5 represents a cross sectional view, with muffle in refractory stainless steel and base in silicon carbide.
Come visibile nella fig. 1, la muffola è costituita da un corpo cavo 1, sostanzialmente di forma ■allungata nella direzione di avanzamento dei prodotti da trattare, che delimita una camera 2, all'interno della quale sono fatti passare in continuo su un nastro trasportatore 3 o posti staticamente i prodotti 4 da trat tare termicamente . As can be seen in fig. 1, the muffle consists of a hollow body 1, substantially elongated in the direction of advancement of the products to be treated, which delimits a chamber 2, inside which they are made to pass continuously on a conveyor belt 3 or statically placed the products 4 to be heat treated.
La caratteristica di novità del trovato risiede nel fatto che il corpo 1 della muffola è realizzato con un impasto a base di materiale ceramico, specificatamente carburo di silicio con percentuale di Si dal 85*/. al 88<*>/.. The novelty of the invention resides in the fact that the body 1 of the muffle is made of a mixture based on ceramic material, specifically silicon carbide with a percentage of Si from 85%. at 88 <*> / ..
L'azione dei resistor! elettrici 5, contenuti nella gabbia é>, provoca il riscaldamento della camera interna 2, la cui temperatura si porta al valore richiesto per il trattamento termico dei prodotti 4 in essa contenuti; il corpo 1 della muffola è rivestito esternamente con un materiale isolante 6 'per impedire perdite di calore verso l'esterno. The action of the resistors! electric 5, contained in the stand é>, causes the internal chamber 2 to heat up, the temperature of which reaches the value required for the heat treatment of the products 4 contained therein; the body 1 of the muffle is externally coated with an insulating material 6 'to prevent heat loss towards the outside.
Una prima possibile variante costruttiva prevede che i resistori 5' siano direttamente annegati entro il corpo 1‘ in carburo di silicio (vedi fig.3). A first possible construction variant provides that the resistors 5 'are directly embedded within the silicon carbide body 1' (see fig. 3).
Una seconda variante costruttiva prevede che il corpo della muffola sia costituito da una parte in carburo di silicio 8 e da una parte in lamiera di acciaio inox refrattario 9. A second construction variant provides that the body of the muffle is made up of a part in silicon carbide 8 and a part in refractory stainless steel sheet 9.
Una terza variante costruttiva prevede che il corpo della muffola sia interamente in lamiera di acciaio inox refrattario 11; con inserita una base 10 di supporto del nastro trasportatore. A third constructive variant provides that the body of the muffle is entirely made of refractory stainless steel sheet 11; with inserted a base 10 for supporting the conveyor belt.
Claims (1)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT97VI000050A IT1292971B1 (en) | 1997-03-28 | 1997-03-28 | MUFFLE TO CARRY OUT HEAT TREATMENTS |
| EP98105206A EP0869191A3 (en) | 1997-03-28 | 1998-03-23 | Muffle for heat treating furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT97VI000050A IT1292971B1 (en) | 1997-03-28 | 1997-03-28 | MUFFLE TO CARRY OUT HEAT TREATMENTS |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| ITVI970050A0 ITVI970050A0 (en) | 1997-03-28 |
| ITVI970050A1 true ITVI970050A1 (en) | 1998-09-28 |
| IT1292971B1 IT1292971B1 (en) | 1999-02-11 |
Family
ID=11426316
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IT97VI000050A IT1292971B1 (en) | 1997-03-28 | 1997-03-28 | MUFFLE TO CARRY OUT HEAT TREATMENTS |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0869191A3 (en) |
| IT (1) | IT1292971B1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106403583A (en) * | 2016-10-31 | 2017-02-15 | 洛阳索莱特材料科技有限公司 | Composite hearth of muffle furnace |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1100782A (en) * | 1954-05-19 | 1955-09-23 | Furnace for metallurgical treatments | |
| CH520909A (en) * | 1970-03-11 | 1972-03-31 | Electrozone Yverdon S A | Gas-fired tunnel kiln - with circular tunnel continuous belt conveyor and internal protective gas generator |
| DE2217271A1 (en) * | 1972-04-11 | 1973-10-31 | Koppers Gmbh Heinrich | METHOD FOR MANUFACTURING A FOR ERECTION OR LINING OF MUFFLED OVENS, IN PARTICULAR COOK OVEN, SUITABLE SILICON CARBIDE STONES |
| GB2072313B (en) * | 1980-03-26 | 1983-08-24 | Fhd Furnaces Ltd | Muffle furnace |
| FR2658276B3 (en) * | 1990-02-09 | 1991-12-13 | Siderurgie Fse Inst Rech | DEVICE FOR LOCALIZED HEATING OF THROUGH METALLURGICAL PRODUCTS. |
| JPH03260591A (en) * | 1990-03-08 | 1991-11-20 | O S Seramu Kk | Continuous sintering furnace |
-
1997
- 1997-03-28 IT IT97VI000050A patent/IT1292971B1/en active IP Right Grant
-
1998
- 1998-03-23 EP EP98105206A patent/EP0869191A3/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| EP0869191A2 (en) | 1998-10-07 |
| IT1292971B1 (en) | 1999-02-11 |
| EP0869191A3 (en) | 2000-10-04 |
| ITVI970050A0 (en) | 1997-03-28 |
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