Infrared heating unit

Abstract

An infrared heating unit with a furnace includes a housing that accommodates a process space, and a heating facility, whereby the process space is bordered, at least in part, by a furnace lining made of quartz glass. In order to provide, on this basis, an infrared heating unit that enables energy-efficient and uniform (homogeneous) heating of the heating goods by infrared radiation to temperatures of even above 600° C., the heating facility is formed by at least one heating substrate that includes a contact surface in contact with a printed conductor made of a resistor material that is electrically conductive and generates heat when current flows through it, whereby the heating substrate includes doped quartz glass, into which an additional component that absorbs in the infrared spectral range is embedded and forms at least a part of the furnace lining.

1 . An infrared heating unit with a furnace comprising:
 a housing that accommodates a process space, and a heating facility, whereby the process space is bordered, at least in part, by a furnace lining made of quartz glass, wherein the heating facility is formed by at least one heating substrate defining a contact surface that is in contact with a printed conductor that is made of a resistor material that is electrically conductive and generates heat when current flows through it, whereby the heating substrate includes doped quartz glass into which an additional component that absorbs in the infrared spectral range is embedded, the heating substrate forming at least a part of the furnace lining.   
     
     
         2 . The infrared heating unit according to  claim 1 , wherein the furnace lining is fully made of the doped quartz glass. 
     
     
         3 . The infrared heating unit according to  claim 2 , wherein a distance between the heating goods and the heating substrate is set to less than 5 mm. 
     
     
         4 . The infrared heating unit according to  claim 2 , the additional component is elemental silicon and is embedded in an amount that effects, in the heating substrate material for wavelengths between 2 and 8 μm, an emissivity ε of at least 0.6 at a temperature of 600° C. and an emissivity ε of at least 0.75 at a temperature of 1,000° C. 
     
     
         5 . The infrared heating unit according to  claim 4 , wherein an amount of the additional component, relative to the weight of the heating substrate, is in the range of 0.1 to 5% by weight. 
     
     
         6 . The infrared heating unit according to  claim 1 , wherein the printed conductor is provided as a burned-in thick film layer and as a line pattern that covers the contact surface appropriately such that an intervening space of at least 1 mm remains between neighbouring sections of the printed conductor. 
     
     
         7 . The infrared heating unit according to  claim 1 , wherein the contact surface is occupied, at least in part, by a cover layer made of porous quartz glass. 
     
     
         8 . The infrared heating unit according to  claim 1 , wherein the heating substrate is provided to be plate-shaped and to have a plate thickness of less than 5 mm. 
     
     
         9 . The infrared heating unit according to  claim 1 , wherein a transport facility for transport of heating goods through the process space is provided that extends through the process space and includes support elements made of quartz glass on which the heating goods are supported. 
     
     
         10 . The infrared heating unit according to  claim 9 , wherein the transport facility includes two continuous transport belts that run parallel to and at a distance from each other, whereby the support elements are provided in the form of quartz glass cylinders that bridge the distance between the transport belts and are connected to the transport belts in a torque-proof manner. 
     
     
         11 . The infrared heating unit according to  claim 10 , wherein the quartz glass cylinders include a coating made of opaque quartz glass. 
     
     
         12 . The infrared heating unit according to  claim 1 , wherein the furnace lining includes at least one heated side and in that the heating facility is designed for generation of an overall power density per surface area in the range of more than 100 kW/m 2  per heated side. 
     
     
         13 . The infrared heating unit according  claim 1 , wherein the printed conductor is provided as a burned-in thick film layer and as a line pattern that covers the contact surface appropriately such that an intervening space of at least 2 mm remains between neighbouring sections of printed conductor. 
     
     
         14 . The infrared heating unit according to  claim 2 , wherein the contact surface is occupied, at least in part, by a cover layer made of porous quartz glass. 
     
     
         15 . The infrared heating unit according to  claim 1 , wherein the contact surface is occupied, at least in part, by a cover layer made of porous quartz glass. 
     
     
         16 . The infrared heating unit according to  claim 1 , wherein the distance between the heating goods and the heating substrate is set to less than 5 mm. 
     
     
         17 . The infrared heating unit according to  claim 1 , wherein the additional component is elemental silicon and is embedded in an amount that effects, in the heating substrate material for wavelengths between 2 and 8 μm, an emissivity ε of at least 0.6 at a temperature of 600° C. and an emissivity ε of at least 0.75 at a temperature of 1,000° C. 
     
     
         18 . The infrared heating unit according to  claim 17 , wherein an amount of the additional component, relative to the weight of the heating substrate, is in the range of 0.1 to 5% by weight. 
     
     
         19 . The infrared heating unit according to  claim 1 , wherein the furnace lining is fully made of the doped quartz glass, wherein the distance between the heating goods and the heating substrate is set to less than 5 mm, wherein the additional component is elemental silicon and is embedded in an amount that effects, in the heating substrate material for wavelengths between 2 and 8 μm, an emissivity ε of at least 0.6 at a temperature of 600° C. and an emissivity ε of at least 0.75 at a temperature of 1,000° C. 
     
     
         20 . The infrared heating unit according to  claim 19 , wherein an amount of the additional component, relative to the weight of the heating substrate, is in the range of 0.1 to 5% by weight.