CH177743A - Process for introducing protective gas into electric annealing and heating furnaces with tubular heating resistors made of silicon carbide. - Google Patents
Process for introducing protective gas into electric annealing and heating furnaces with tubular heating resistors made of silicon carbide.Info
- Publication number
- CH177743A CH177743A CH177743DA CH177743A CH 177743 A CH177743 A CH 177743A CH 177743D A CH177743D A CH 177743DA CH 177743 A CH177743 A CH 177743A
- Authority
- CH
- Switzerland
- Prior art keywords
- silicon carbide
- protective gas
- heating resistors
- heating
- introducing protective
- Prior art date
Links
Landscapes
- Non-Adjustable Resistors (AREA)
- Resistance Heating (AREA)
Description
Verfahren zum Einführen von Schutzgas in elektrischen Glülr und Wärmeöfen mit röhrenförmigen Heizwiderständen aus Siliziumkarbid. Es ist bekannt, elektrische Ofen mit röh renförmigen Heizwiderständen aus Silizium karbid im Betriebe mit einem indifferenten leas, z. B. zum Zweck des Schutzes des darin zu. behandelnden Gutes gegen Abbrand oder Verzunderung, zu beschicken. Dies geschah bisher durch besondere Öffnungen in der Ofenwandung oder durch die Ofentür.
Nach dem Verfahren gemäss der Erfin dung wird das Gas in die Widerstandsrohre selbst eingeführt, z. B. von beiden Enden her oder, sofern das andere Ende verschlossen gehalten wird, von einem Ende her, und zwar unter Überdruck. Es hat sich nämlich her ausgestellt, dass wegen der Gasdurchlässig keit der Widerstände auch auf diesem Wege eine ausreichende Gaszufuhr sichergestellt wird, ohne dass es erforderlich ist, gesonderte Öffnungen für die Gaszufuhr vorzusehen.
Das Verfahren gemäss der Erfindung hat darüber hinaus den Vorteil, dass eine Oxy- dation der Heizwiderstände vermieden wird. Dies wurde bisher bei Zufuhr des indifferen ten Gases durch gesonderte Öffnungen oder durch die Ofentür deshalb nicht erreicht, weil im Innern des Ofens kein solcher Druck vorhanden war, der ausgereicht hätte, um das indifferente Gas durch die Wandung der Heizwiderstände in ,das Innere der gewöhn lich mit der Aussenluft in Verbindung ste henden Widerstandsrohre hindurchzudrücken.
Es ist also günstigstenfalles lediglich eine dünne äussere .Schicht der Widerstände gegen Oxydation geschützt, nicht aber der Teil, der an den Hohlraum der Heizwiderstände an grenzt, der aber besonders stark der Oxyda tion ausgesetzt ist.
Durch die Herabsetzung der Oxydations gefahr wird auch noch der Vorteil erzielt, dass es nunmehr ermöglicht ist, die Heiz- widerstände zur Erzielung höherer Tempera turen zu verwenden als bisher. Dies wie- derum hat einen nicht unbeträchtlichen wirt schaftlichen Vorteil zur Folge.
Method for introducing protective gas into electrical furnace and heating furnace with tubular heating resistors made of silicon carbide. It is known, electric furnace with Röh reniform heating resistors made of silicon carbide in operation with an indifferent leas, z. B. for the purpose of protecting it too. goods to be treated against burn-off or scaling. Until now, this has been done through special openings in the furnace wall or through the furnace door.
According to the method according to the invention, the gas is introduced into the resistance tubes themselves, e.g. B. from both ends or, if the other end is kept closed, from one end, under excess pressure. It has been shown that, because of the gas permeability of the resistors, a sufficient gas supply is also ensured in this way without it being necessary to provide separate openings for the gas supply.
The method according to the invention also has the advantage that oxidation of the heating resistors is avoided. So far, this has not been achieved when the indifferent gas is supplied through separate openings or through the oven door because there was no pressure inside the oven that would have been sufficient to pass the indifferent gas through the wall of the heating resistors into the interior of the oven Lich standing resistance pipes in contact with the outside air must be pushed through.
In the best case scenario, only a thin outer layer of the resistors is protected against oxidation, but not the part that borders the cavity of the heating resistors, but which is particularly exposed to the oxidation.
By reducing the risk of oxidation, the advantage is also achieved that it is now possible to use the heating resistors to achieve higher temperatures than before. This in turn has a not inconsiderable economic advantage.
Claims (1)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE177743X | 1933-12-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
CH177743A true CH177743A (en) | 1935-06-15 |
Family
ID=5703191
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CH177743D CH177743A (en) | 1933-12-15 | 1934-08-30 | Process for introducing protective gas into electric annealing and heating furnaces with tubular heating resistors made of silicon carbide. |
Country Status (1)
Country | Link |
---|---|
CH (1) | CH177743A (en) |
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1934
- 1934-08-30 CH CH177743D patent/CH177743A/en unknown
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