EP0489834B1 - Infra-red radiation emission arrangement - Google Patents
Infra-red radiation emission arrangement Download PDFInfo
- Publication number
- EP0489834B1 EP0489834B1 EP90913501A EP90913501A EP0489834B1 EP 0489834 B1 EP0489834 B1 EP 0489834B1 EP 90913501 A EP90913501 A EP 90913501A EP 90913501 A EP90913501 A EP 90913501A EP 0489834 B1 EP0489834 B1 EP 0489834B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- infra
- red radiation
- radiation
- red
- coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/68—Heating arrangements specially adapted for cooking plates or analogous hot-plates
- H05B3/74—Non-metallic plates, e.g. vitroceramic, ceramic or glassceramic hobs, also including power or control circuits
- H05B3/744—Lamps as heat source, i.e. heating elements with protective gas envelope, e.g. halogen lamps
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/0033—Heating devices using lamps
- H05B3/0071—Heating devices using lamps for domestic applications
- H05B3/008—Heating devices using lamps for domestic applications for heating of inner spaces
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/0033—Heating devices using lamps
- H05B3/009—Heating devices using lamps heating devices not specially adapted for a particular application
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/40—Heating elements having the shape of rods or tubes
- H05B3/42—Heating elements having the shape of rods or tubes non-flexible
- H05B3/44—Heating elements having the shape of rods or tubes non-flexible heating conductor arranged within rods or tubes of insulating material
Definitions
- This invention relates to an infra-red radiation emission arrangement.
- Infra-red radiation emitters which comprise a tungsten filament in an envelope of vitreous silica. Such emitters have a fast response, in that the radiation emitted can change from full power to negligible values within one second of the emitter being switched off.
- Such emitters emit radiation primarily in the short wavelength of infra-red radiation, ie. in the range of from 0.8 to 2.5 microns or in the medium wavelength of infra-red radiation, from 1.2 to 4.0 microns.
- EP-A-0134090 and GB-A-2160400 It is known from EP-A-0134090 and GB-A-2160400 to provide an infra-red radiation emission arrangement comprising a primary source of short or medium wavelength infra-red radiation arranged to emit the radiation in a first direction, and a substrate of thermally insulating material having a surface spaced apart from the primary source and facing the first direction. This arrangement does not, however, provide for significant re-radiation of long wavelength infra-red radiation since the surface has a high reflectivity.
- an infra-red radiation emission arrangement comprising: a primary source of short or medium wavelength infra-red radiation arranged to emit said short or medium wavelength infra-red radiation in a first direction; and a substrate of thermally insulating material having a surface spaced apart from said primary source and facing said first direction; characterised by a coating of an infra-red radiation absorptive material provided on at least a part of said surface on which, in use, said short or medium wavelength infra-red radiation is incident, said coating being adapted to absorb said short or medium wavelength infra-red radiation whereby said coating is heated to re-radiate infra-red radiation at a longer wavelength in a second direction, substantially opposite said first direction; said infra-red absorptive material having a normal spectral emittance at infra-red wavelengths of at least 0.8.
- radiation from said primary source is incident on, and absorbed by, said coating.
- the substrate is thermally insulating, little heat is conducted away from said coating and so the coating is maintained above ambient temperature.
- the temperature achieved by the infra-red absorptive material will depend upon the intensity of the short or medium wavelength infra-red radiation from said primary source incident thereon, and on the absorptivity/reflectivity of said coating.
- the intensity of radiation incident on said coating is itself dependent upon the positioning and shaping of said coating relative to said primary source. Accordingly, said coating will be at a lower temperature, and so will emit radiation of a longer wavelength than, said primary source.
- a part of said surface is reflective of radiation at infra-red wavelengths.
- the total radiation output of such an arrangement is a combination of the short or medium wavelength radiation from said primary source, reflected by said surface, and medium/long wavelength radiation emitted by said coating. In this way, the total radiation output of the arrangement can be further controlled.
- said coating has a low thermal mass, responding rapidly in temperature to variations in the incident infra-red radiation.
- the thermal response of the arrangement is dependent upon the thermal response of said primary source, which can be very fast as indicated previously and the thermal mass of that part of the substrate which responds to the incident infra-red radiation. Accordingly, an arrangement according to this aspect of the present invention has a relatively fast thermal response and an emission spectrum in the long wavelength infra-red.
- the arrangement of the invention has the advantages that it has a faster thermal response time when emitting in the long wavelength region of the infra-red spectrum than known emission arrangements, and also that it provides for controllable broadening of the useful wavelength limits of the total radiation output from the arrangement as compared with a conventional single hot body infra-red emitter.
- said surface of the coating re-radiates at least 50%, and preferably at least 85% of the radiation energy incident on said coating from the primary source.
- said primary source includes an envelope, a part of said envelope through which radiation is transmitted away from said surface being coated with an infra-red radiation absorptive material which, in operation, is heated to re-radiate infra-red radiation at a longer wavelength.
- the arrangement can include a secondary reflector to direct radiation from said primary source towards said surface.
- Figure 1 shows three infra-red radiation emission arrangements 1, 2 and 3, each comprising a short wavelength infra-red radiation emitter 4, such as a tungsten quartz emitter.
- a short wavelength infra-red radiation emitter 4 such as a tungsten quartz emitter.
- the spectral output of a known tungsten quartz emitter is shown in Figure 2.
- Each short wavelength infra-red radiation emitter 4 has an associated reflector 5 which is arranged to direct infra-red radiation from the emitter 4 towards a concave surface 6 of a high efficiency thermally insulating substrate 7.
- the substrate 7 may be made of a low thermal mass material, such as ceramic fibres or microporous thermally insulating material, which reflects radiation of infra-red wavelengths as well as being thermally insulating.
- the surface 6 has a coating 8 on which the radiation from the associated emitter 4 is incident.
- the coating 8 is of an infra-red radiation absorptive material, such as copper oxide, boron carbide or iron oxide.
- the coating 8 is heated by the incident radiation from the associated emitter 4 (indicated by arrow S) and emits infra-red radiation in the medium/long wavelength part of the infra-red radiation spectrum (as indicated by the arrow M/L).
- the coating is very thin, so that it has a low thermal mass and so responds quickly to variations in the infra-red radiation incident thereon.
- the coating 8 may be made of any infra-red radiation absorptive material which has a high emissivity, preferably of at least 0.8.
- Table 1 shows a number of high emissivity materials and indicates the conditions at which this high emissivity was measured, namely the wavelength range of radiation emitted and the temperature of the material at which this emission took place.
- Figure 3 shows a second embodiment of a radiation emission arrangement according to the present invention.
- the surface 6 is provided as a planar surface. Surfaces having other geometries may also be used.
- Figure 4 shows a third embodiment of an infra-red radiation emission arrangement prepared in accordance with the present invention.
- the primary source 4 is shown in greater detail as a tungsten filament 10 in an envelope 12 of vitreous silica.
- Part of the envelope 12 through which radiation from the filament 10 is transmitted, away from the substrate 7, is coated with an infra-red radiation absorptive material having a high emissivity. Suitable materials are those disclosed in table 1 previously.
- the coating 14 on the envelope 12 is heated by the incident radiation from the tungsten filament 10 and emits infra-red radiation in the medium/long wavelength part of the infra-red radiation spectrum.
- An advantage of this embodiment over the embodiments of Figures 1 and 3 is that the effect of shielding of radiation from the coating 8 by the secondary reflector 5 of Figure 1 and 3 on the total radiation output of the embodiment is reduced.
- the arrow s indicates short wavelength radiation from the primary source and the arrow M/L indicate longer wavelength radiation.
- each infra-red radiation emission arrangement 1, 2 or 3 can be set by appropriate selection of the mass, ie. the thickness, and the material of the coating 8, and of the position of the emitter 4 and its reflector 5 relative to the coated surface 6 of the substrate 7, such selection determining the temperature of the coating 8 during operation.
- Figure 5 shows a substrate 7 for use with a fourth embodiment of an infra-red radiation emission arrangement provided in accordance with the present invention.
- the surface 6 is partially not covered by the coating 8. Accordingly, infra-red radiation incident on the uncoated parts 9 from the associated emitter 4 will be directly reflected therefrom.
- the total radiation output of this arrangement is a combination of radiation at medium/long wavelengths emitted from the coating 8 and infra-red radiation of short/medium wavelengths reflected from the uncoated part 9.
- the coating 8 has a sufficient quantity of infra-red absorptive material per unit surface area of the part of the substrate 7 that substantially all of the incident infra-red radiation is absorbed and re-radiated at longer wavelengths.
- the coating 8 may include an insufficient quantity of infra-red radiation absorptive material to absorb all of the incident infra-red radiation. It is envisaged that this may be because the quantity of material is insufficient to coat the entire surface of the substrate 7 so that incident radiation is reflected from the uncoated parts. In this latter case, the infra-red radiation that is not absorbed by the coating 8 is transmitted to the substrate 7 and reflected therefrom. Accordingly, as with the embodiment of Figure 5, the total radiation output of such an arrangement is a combination of radiation at medium/long wavelength emitted from the coating 8 and infra-red radiation of short/medium wavelengths reflected from the substrate 7.
- Figures 6 and 7 show spectral output for infra-red emission arrangements provided in accordance with the present invention.
- the substrate 7 was made of an alumino-silicate ceramic fibre board (for example "Kaowool 1600" manufactured by Morgan Ceramic Fibres Limited) of thickness 5 mm to 7 mm with a backing of microporous thermal insulation board (for example, "Microtherm” manufactured by Micropore Insulation Limited) of thickness 25 mm.
- a single board of ceramic fibre or Microtherm of thickness 25 mm to 30 mm may be used.
- the quoted thermal conductivities of the substrate material are 0.079 W/mK for Kaowool and 0.025 W/mK for Microtherm.
- the reflectivity of these two substrate materials at short wavelengths of infra-red radiation is high - a graph showing the reflectivity of Microtherm is provided as Figure 8.
- the material used for the absorptive coating is silicon carbide although successful emission arrangements have also been made using coatings of copper oxide, boron silicide and molybdenum disilicide.
- silicon carbide is known to have an emissivity of at least 0.8. Its absorptivity is dependent on the quantity of material provided per unit surface area of substrate. Above a certain value of the coating thickness, the absorptivity equals the emissivity and the coating is opaque to the incident radiation. For the particular silicon carbide used, this critical value was 150 grams per square metre.
- the substrate 7 and coating 8 were planar and the substate and primary sources were arranged horizontally.
- Figure 6 shows the effect of the amount of material in the coating on the spectral radiation output from the substrate.
- the details of the examples are as follows:
- the spectral radiation output for example C is primarily at wavelengths greater than 2 microns.
- the spectral radiation output for example B includes a significant component at wavelengths less than 2 microns which is contributed by reflection from the Kaowool.
- Figure 7 shows the effect of leaving part of the substrate surface uncoated, the remainder being coated with silicon carbide of coat weight 150 grams per square metre. The details are as follows:
- example A the spectral output of example A is primarily at the short wavelength end of the infra-red radiation spectrum and although this example, which is not an emission arrangement in accordance with the present invention, has the best thermal response, this is primarily due to the fast thermal response of the primary source.
- the other examples B, C, D and E have a substantially faster thermal response than the commercial long wavelength radiation emitters such as Pearlco 500 watt and Vulcan 400 watt.
- Arrangements in accordance with the invention can be used as heat/curing sources in commercial process ovens, or as domestic heating sources.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Resistance Heating (AREA)
Abstract
Description
- This invention relates to an infra-red radiation emission arrangement.
- Infra-red radiation emitters are known which comprise a tungsten filament in an envelope of vitreous silica. Such emitters have a fast response, in that the radiation emitted can change from full power to negligible values within one second of the emitter being switched off. However, such emitters emit radiation primarily in the short wavelength of infra-red radiation, ie. in the range of from 0.8 to 2.5 microns or in the medium wavelength of infra-red radiation, from 1.2 to 4.0 microns.
- It is also known to provide long wavelength infra-red radiation emitters, emitting radiation in the wavelength range from 2 to 10 microns, in which a substrate is maintained at a temperature which determines the wavelength of the emitted radiation. However, such emitters have a slow thermal response, of the order of 200 to 300 seconds.
- It is known from EP-A-0134090 and GB-A-2160400 to provide an infra-red radiation emission arrangement comprising a primary source of short or medium wavelength infra-red radiation arranged to emit the radiation in a first direction, and a substrate of thermally insulating material having a surface spaced apart from the primary source and facing the first direction. This arrangement does not, however, provide for significant re-radiation of long wavelength infra-red radiation since the surface has a high reflectivity.
- It is an object of the present invention to provide an improved infra-red radiation emission arrangement.
- According to the present invention there is provided an infra-red radiation emission arrangement comprising:
a primary source of short or medium wavelength infra-red radiation arranged to emit said short or medium wavelength infra-red radiation in a first direction;
and a substrate of thermally insulating material having a surface spaced apart from said primary source and facing said first direction;
characterised by a coating of an infra-red radiation absorptive material provided on at least a part of said surface on which, in use, said short or medium wavelength infra-red radiation is incident, said coating being adapted to absorb said short or medium wavelength infra-red radiation whereby said coating is heated to re-radiate infra-red radiation at a longer wavelength in a second direction, substantially opposite said first direction; said infra-red absorptive material having a normal spectral emittance at infra-red wavelengths of at least 0.8. - In an arrangement provided in accordance with the present invention, radiation from said primary source is incident on, and absorbed by, said coating. As the substrate is thermally insulating, little heat is conducted away from said coating and so the coating is maintained above ambient temperature. The temperature achieved by the infra-red absorptive material will depend upon the intensity of the short or medium wavelength infra-red radiation from said primary source incident thereon, and on the absorptivity/reflectivity of said coating. The intensity of radiation incident on said coating is itself dependent upon the positioning and shaping of said coating relative to said primary source. Accordingly, said coating will be at a lower temperature, and so will emit radiation of a longer wavelength than, said primary source.
- Advantageously, a part of said surface is reflective of radiation at infra-red wavelengths. The total radiation output of such an arrangement is a combination of the short or medium wavelength radiation from said primary source, reflected by said surface, and medium/long wavelength radiation emitted by said coating. In this way, the total radiation output of the arrangement can be further controlled.
- Advantageously, said coating has a low thermal mass, responding rapidly in temperature to variations in the incident infra-red radiation. The thermal response of the arrangement is dependent upon the thermal response of said primary source, which can be very fast as indicated previously and the thermal mass of that part of the substrate which responds to the incident infra-red radiation. Accordingly, an arrangement according to this aspect of the present invention has a relatively fast thermal response and an emission spectrum in the long wavelength infra-red.
- The arrangement of the invention has the advantages that it has a faster thermal response time when emitting in the long wavelength region of the infra-red spectrum than known emission arrangements, and also that it provides for controllable broadening of the useful wavelength limits of the total radiation output from the arrangement as compared with a conventional single hot body infra-red emitter.
- Preferably said surface of the coating re-radiates at least 50%, and preferably at least 85% of the radiation energy incident on said coating from the primary source.
- Advantageously said primary source includes an envelope, a part of said envelope through which radiation is transmitted away from said surface being coated with an infra-red radiation absorptive material which, in operation, is heated to re-radiate infra-red radiation at a longer wavelength.
- Alternatively, the arrangement can include a secondary reflector to direct radiation from said primary source towards said surface.
- Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:
- Figure 1 shows a composite arrangement comprising three infra-red radiation emission arrangements provided in accordance with the present invention;
- Figure 2 shows the spectral output of a tungsten quartz emitter for use with an arrangement according to the present invention;
- Figures 3 and 4 show second and third embodiments of infra-red radiation emission arrangements provided in accordance with the present invention;
- Figure 5 shows a substrate for use with a fourth embodiment of an infra-red radiation emission arrangement provided in accordance with the present invention;
- Figures 6 and 7 show spectral outputs of arrangements provided in accordance with the present invention;
- and Figure 8 shows the reflectivity of a substrate for use with an arrangement according to the present invention.
- Figure 1 shows three infra-red
radiation emission arrangements 1, 2 and 3, each comprising a short wavelength infra-red radiation emitter 4, such as a tungsten quartz emitter. The spectral output of a known tungsten quartz emitter is shown in Figure 2. Each short wavelength infra-red radiation emitter 4 has an associatedreflector 5 which is arranged to direct infra-red radiation from theemitter 4 towards aconcave surface 6 of a high efficiency thermally insulatingsubstrate 7. Thesubstrate 7 may be made of a low thermal mass material, such as ceramic fibres or microporous thermally insulating material, which reflects radiation of infra-red wavelengths as well as being thermally insulating. Thesurface 6 has acoating 8 on which the radiation from the associatedemitter 4 is incident. Thecoating 8 is of an infra-red radiation absorptive material, such as copper oxide, boron carbide or iron oxide. Thecoating 8 is heated by the incident radiation from the associated emitter 4 (indicated by arrow S) and emits infra-red radiation in the medium/long wavelength part of the infra-red radiation spectrum (as indicated by the arrow M/L). The coating is very thin, so that it has a low thermal mass and so responds quickly to variations in the infra-red radiation incident thereon. - The
coating 8 may be made of any infra-red radiation absorptive material which has a high emissivity, preferably of at least 0.8. Table 1 shows a number of high emissivity materials and indicates the conditions at which this high emissivity was measured, namely the wavelength range of radiation emitted and the temperature of the material at which this emission took place. - Figure 3 shows a second embodiment of a radiation emission arrangement according to the present invention. In view of the similarity between this embodiment and the embodiment of Figure 1, like parts are designated by like references. In the embodiment of Figure 3, the
surface 6 is provided as a planar surface. Surfaces having other geometries may also be used. - Figure 4 shows a third embodiment of an infra-red radiation emission arrangement prepared in accordance with the present invention. Like parts to those of Figures 1 and 3 are designated by like references. In this embodiment, the
primary source 4 is shown in greater detail as atungsten filament 10 in an envelope 12 of vitreous silica. Part of the envelope 12 through which radiation from thefilament 10 is transmitted, away from thesubstrate 7, is coated with an infra-red radiation absorptive material having a high emissivity. Suitable materials are those disclosed in table 1 previously. As with thecoating 8 on thesubstrate 7, thecoating 14 on the envelope 12 is heated by the incident radiation from thetungsten filament 10 and emits infra-red radiation in the medium/long wavelength part of the infra-red radiation spectrum. An advantage of this embodiment over the embodiments of Figures 1 and 3 is that the effect of shielding of radiation from thecoating 8 by thesecondary reflector 5 of Figure 1 and 3 on the total radiation output of the embodiment is reduced. In Figure 4, the arrow s indicates short wavelength radiation from the primary source and the arrow M/L indicate longer wavelength radiation. - As discussed above, the total radiation output of each infra-red
radiation emission arrangement 1, 2 or 3 can be set by appropriate selection of the mass, ie. the thickness, and the material of thecoating 8, and of the position of theemitter 4 and itsreflector 5 relative to the coatedsurface 6 of thesubstrate 7, such selection determining the temperature of thecoating 8 during operation. - Figure 5 shows a
substrate 7 for use with a fourth embodiment of an infra-red radiation emission arrangement provided in accordance with the present invention. Like parts to those of Figures 1 and 3 are designated by like references. In this embodiment, thesurface 6 is partially not covered by thecoating 8. Accordingly, infra-red radiation incident on the uncoated parts 9 from the associatedemitter 4 will be directly reflected therefrom. The total radiation output of this arrangement is a combination of radiation at medium/long wavelengths emitted from thecoating 8 and infra-red radiation of short/medium wavelengths reflected from the uncoated part 9. - In the embodiments described previously, the
coating 8 has a sufficient quantity of infra-red absorptive material per unit surface area of the part of thesubstrate 7 that substantially all of the incident infra-red radiation is absorbed and re-radiated at longer wavelengths. Alternatively, thecoating 8 may include an insufficient quantity of infra-red radiation absorptive material to absorb all of the incident infra-red radiation. It is envisaged that this may be because the quantity of material is insufficient to coat the entire surface of thesubstrate 7 so that incident radiation is reflected from the uncoated parts. In this latter case, the infra-red radiation that is not absorbed by thecoating 8 is transmitted to thesubstrate 7 and reflected therefrom. Accordingly, as with the embodiment of Figure 5, the total radiation output of such an arrangement is a combination of radiation at medium/long wavelength emitted from thecoating 8 and infra-red radiation of short/medium wavelengths reflected from thesubstrate 7. - Figures 6 and 7 show spectral output for infra-red emission arrangements provided in accordance with the present invention. In the examples, the
substrate 7 was made of an alumino-silicate ceramic fibre board (for example "Kaowool 1600" manufactured by Morgan Ceramic Fibres Limited) ofthickness 5 mm to 7 mm with a backing of microporous thermal insulation board (for example, "Microtherm" manufactured by Micropore Insulation Limited) of thickness 25 mm. Alternatively, a single board of ceramic fibre or Microtherm of thickness 25 mm to 30 mm may be used. The quoted thermal conductivities of the substrate material are 0.079 W/mK for Kaowool and 0.025 W/mK for Microtherm. The reflectivity of these two substrate materials at short wavelengths of infra-red radiation is high - a graph showing the reflectivity of Microtherm is provided as Figure 8. - In the examples, the material used for the absorptive coating is silicon carbide although successful emission arrangements have also been made using coatings of copper oxide, boron silicide and molybdenum disilicide. As indicated previously, silicon carbide is known to have an emissivity of at least 0.8. Its absorptivity is dependent on the quantity of material provided per unit surface area of substrate. Above a certain value of the coating thickness, the absorptivity equals the emissivity and the coating is opaque to the incident radiation. For the particular silicon carbide used, this critical value was 150 grams per square metre.
- In each example, the
substrate 7 andcoating 8 were planar and the substate and primary sources were arranged horizontally. - Figure 6 shows the effect of the amount of material in the coating on the spectral radiation output from the substrate. The details of the examples are as follows:
- Example A - uncoated Kaowool;
- Example B - Kaowool with a coating of silicon carbide of
coat weight 50 grams per square metre; - Example C - Kaowool with a coating of silicon carbide of coat weight 150 grams per square metre.
- It can be seen that the spectral radiation output for example C is primarily at wavelengths greater than 2 microns. The spectral radiation output for example B, however, includes a significant component at wavelengths less than 2 microns which is contributed by reflection from the Kaowool.
- Figure 7 shows the effect of leaving part of the substrate surface uncoated, the remainder being coated with silicon carbide of coat weight 150 grams per square metre. The details are as follows:
- Example A - uncoated Kaowool;
- Example D - equal strips of coated and uncoated Kaowool;
- Example E - surface area of coating is twice that of the uncoated Kaowool;
- Example F - Kaowool completely coated;
- It can be seen that as the area of uncoated Kaowool is increased, the proportion of infra-red radiation at wavelengths less than 2 microns increases.
- As shown in Figures 6 and 7, the spectral output of example A is primarily at the short wavelength end of the infra-red radiation spectrum and although this example, which is not an emission arrangement in accordance with the present invention, has the best thermal response, this is primarily due to the fast thermal response of the primary source. The other examples B, C, D and E have a substantially faster thermal response than the commercial long wavelength radiation emitters such as Pearlco 500 watt and Vulcan 400 watt.
- Arrangements in accordance with the invention can be used as heat/curing sources in commercial process ovens, or as domestic heating sources.
- Modifications to the embodiments described within the scope of the present invention will be apparent to those skilled in the art.
Claims (14)
- An infra-red radiation emission arrangement comprising:
a primary source (4) of short or medium wavelength infra-red radiation arranged to emit said short or medium wavelength infra-red radiation in a first direction;
and a substrate (7) of thermally insulating material having a surface (6) spaced apart from said primary source (4) and facing said first direction;
characterised by a coating (8) of an infra-red radiation absorptive material provided on at least a part of said surface (6) on which, in use, said short or medium wavelength infra-red radiation is incident, said coating (8) being adapted to absorb said short or medium wavelength infra-red radiation whereby said coating (8) is heated to re-radiate infra-red radiation at a longer wavelength in a second direction, substantially opposite said first direction; said infra-red absorptive material having a normal spectral emittance at infra-red wavelengths of at least 0.8. - An arrangement according to Claim 1 characterised in that said coating (8) re-radiates at least 50% of the incident infra-red radiation energy.
- An arrangement according to Claim 2 characterised in that coating (8) re-radiates at least 85% of the incident infra-red radiation energy.
- An arrangement according to any preceding claim characterised in that said coating (8) covers only a part of said surface (6) and a part of said surface (6) not covered by said coating (8) is reflective of radiation at infra-red wavelengths.
- An arrangement according to any preceding claim characterised in that the quantity of said infra-red radiation absorptive material provided per unit surface area of said at least part of said surface (6) is sufficient to absorb substantially all of said short and medium wavelength infra-red radiation.
- An arrangement according to any preceding claim characterised in that said surface (6) is reflective of radiation at infra-red wavelengths and the quantity of said infra-red radiation absorptive material provided per unit surface area of said at least part of said surface (6) is insufficient to absorb substantially all of said short and medium wavelength infra-red radiation whereby a part of said short and medium wavelength infra-red radiation is reflected from said surface (6).
- An arrangement according to any preceding claim characterised in that said infra-red radiation absorptive material is selected from the group consisting of copper oxide, boron carbide and iron oxide.
- An arrangement according to any preceding claim characterised in that said infra-red radiation absorptive material is silicon carbide.
- An arrangement according to any preceding claim characterised in that said thermally insulating material comprises ceramic fibre.
- An arrangement according to any one of Claims 1 to 8 characterisd in that said thermally insulating material is microporous thermally insulating material.
- An arrangement according to any preceding claim characterised in that said primary source (4) includes an envelope (12).
- An arrangement according to Claim 11 characterised in that said primary source (4) includes a tungsten filament (10) in said envelope (12).
- An arrangement according to Claims 11 or 12 characterised in that said primary source (4) is arranged to emit said short or medium wavelength infra-red radiation also in said second direction, and a part of said envelope (12) through which radiation is transmitted in said second direction is provided with a primary source coating (4) formed of an infra-red radiation absorptive material which absorbs said short or medium wavelength infra-red radiation emitted by said primary source (4) in said second direction, whereby said primary source coating (14) is heated to re-radiate infra-red radiation at a longer wavelength.
- An arrangement according to any one of Claims 1 to 12 characterised by a secondary reflector (5) to direct radiation from said primary source (4) towards said surface (6) in said first direction.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8919700 | 1989-08-31 | ||
GB898919700A GB8919700D0 (en) | 1989-08-31 | 1989-08-31 | Infra-red radiation emission arrangement |
PCT/GB1990/001346 WO1991003915A1 (en) | 1989-08-31 | 1990-08-31 | Infra-red radiation emission arrangement |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0489834A1 EP0489834A1 (en) | 1992-06-17 |
EP0489834B1 true EP0489834B1 (en) | 1994-12-07 |
Family
ID=10662329
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90913501A Expired - Lifetime EP0489834B1 (en) | 1989-08-31 | 1990-08-31 | Infra-red radiation emission arrangement |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0489834B1 (en) |
DE (1) | DE69014892T2 (en) |
ES (1) | ES2064760T3 (en) |
GB (1) | GB8919700D0 (en) |
WO (1) | WO1991003915A1 (en) |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2257002A (en) * | 1991-06-21 | 1992-12-23 | Electrolux Cookers | Ceramic electric hob |
GB9214380D0 (en) * | 1992-07-07 | 1992-08-19 | Sev Furnaces Ltd | Radiation transmitting apparatus |
US5751896A (en) * | 1996-02-22 | 1998-05-12 | Micron Technology, Inc. | Method and apparatus to compensate for non-uniform film growth during chemical vapor deposition |
US6188836B1 (en) * | 1999-03-22 | 2001-02-13 | Appliance Development Corporation | Portable radiant heater with two reflectors |
JP3360072B2 (en) * | 2000-07-10 | 2002-12-24 | アイシー テック コ.,エルティーディー | Electric heater |
US6526227B2 (en) * | 2001-02-27 | 2003-02-25 | Ic Tech Co., Ltd. | Radiant electric heater |
US7507575B2 (en) | 2005-04-01 | 2009-03-24 | 3M Innovative Properties Company | Multiplex fluorescence detection device having removable optical modules |
US7709249B2 (en) | 2005-04-01 | 2010-05-04 | 3M Innovative Properties Company | Multiplex fluorescence detection device having fiber bundle coupling multiple optical modules to a common detector |
US20070009382A1 (en) * | 2005-07-05 | 2007-01-11 | William Bedingham | Heating element for a rotating multiplex fluorescence detection device |
US7527763B2 (en) | 2005-07-05 | 2009-05-05 | 3M Innovative Properties Company | Valve control system for a rotating multiplex fluorescence detection device |
JP4743495B2 (en) * | 2005-07-08 | 2011-08-10 | 東京エレクトロン株式会社 | Fluid heating device |
US9121055B2 (en) | 2008-04-24 | 2015-09-01 | 3M Innovative Properties Company | Analysis of nucleic acid amplification curves using wavelet transformation |
CN108180991A (en) * | 2018-03-05 | 2018-06-19 | 清华大学 | A kind of infrared narrowband heat radiator and preparation method |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1114485A (en) * | 1954-10-25 | 1956-04-12 | infrared transmitter | |
US3179789A (en) * | 1963-08-26 | 1965-04-20 | Joseph A Gialanella | Radiant energy generating and distributing apparatus |
US3546431A (en) * | 1969-04-25 | 1970-12-08 | Erich L Gibbs | Immersion heater and method of making the same |
US3805024A (en) * | 1973-06-18 | 1974-04-16 | Irex Corp | Electrical infrared heater with a coated silicon carbide emitter |
GB1599452A (en) * | 1978-02-02 | 1981-10-07 | Thorn Emi Ltd | Infra-red heating device |
GB8321717D0 (en) * | 1983-08-12 | 1983-09-14 | Thorn Emi Domestic Appliances | Heating apparatus |
GB2160400B (en) * | 1984-06-09 | 1987-04-15 | Micropore International Ltd | Radiant heater |
-
1989
- 1989-08-31 GB GB898919700A patent/GB8919700D0/en active Pending
-
1990
- 1990-08-31 WO PCT/GB1990/001346 patent/WO1991003915A1/en active IP Right Grant
- 1990-08-31 EP EP90913501A patent/EP0489834B1/en not_active Expired - Lifetime
- 1990-08-31 ES ES90913501T patent/ES2064760T3/en not_active Expired - Lifetime
- 1990-08-31 DE DE69014892T patent/DE69014892T2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
WO1991003915A1 (en) | 1991-03-21 |
ES2064760T3 (en) | 1995-02-01 |
DE69014892T2 (en) | 1995-04-27 |
DE69014892D1 (en) | 1995-01-19 |
GB8919700D0 (en) | 1989-10-11 |
EP0489834A1 (en) | 1992-06-17 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0489834B1 (en) | Infra-red radiation emission arrangement | |
JP5450331B2 (en) | Method and apparatus for uniformly heating glass and / or glass ceramic using infrared radiation | |
US6348676B2 (en) | Rapid cooking device using infrared light | |
US5391408A (en) | Method for firing enamel on a metal article | |
US4563572A (en) | High-efficiency task heater | |
GB2161348A (en) | Radiation heater reflector | |
US5055819A (en) | Temperature switch | |
JP7211029B2 (en) | Method for manufacturing glass article and method for heating thin glass | |
EP0150087B1 (en) | A thermal limiting device | |
WO1994001982A1 (en) | Radiant heating apparatus | |
JP2978716B2 (en) | Far infrared heater | |
JP2917542B2 (en) | Light heat source iron | |
DE59007428D1 (en) | Cooking appliance with a radiant heater. | |
JP3296676B2 (en) | Electric hot plate | |
JPH0625913Y2 (en) | Heat ray radiator | |
US6993253B2 (en) | Heating apparatus with special selective radiant material partially coated thereon | |
SU1083253A1 (en) | Electric incandescent lamp | |
JPH0576699A (en) | Iron | |
JPS6038534A (en) | Reflector for stove | |
KR200252935Y1 (en) | Far-infrared heater of fan shape | |
JP2023548025A (en) | Infrared radiators and infrared radiating components | |
JP2870203B2 (en) | Cordless iron | |
JP3932364B2 (en) | Heat radiation source | |
JPH0527831Y2 (en) | ||
KR930007831Y1 (en) | Lighting apparatus |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19920205 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): BE CH DE ES FR GB IT LI NL |
|
17Q | First examination report despatched |
Effective date: 19930921 |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: EA TECHNOLOGY LIMITED |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE PATENT HAS BEEN GRANTED |
|
ITF | It: translation for a ep patent filed |
Owner name: BARZANO' E ZANARDO ROMA S.P.A. |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): BE CH DE ES FR GB IT LI NL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Effective date: 19941207 Ref country code: BE Effective date: 19941207 |
|
REF | Corresponds to: |
Ref document number: 69014892 Country of ref document: DE Date of ref document: 19950119 |
|
REG | Reference to a national code |
Ref country code: ES Ref legal event code: FG2A Ref document number: 2064760 Country of ref document: ES Kind code of ref document: T3 |
|
ET | Fr: translation filed | ||
NLV1 | Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act | ||
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Effective date: 19950831 Ref country code: CH Effective date: 19950831 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: ES Free format text: LAPSE BECAUSE OF THE APPLICANT RENOUNCES Effective date: 19950901 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19960808 Year of fee payment: 7 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19960830 Year of fee payment: 7 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 19980430 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 19980501 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20000623 Year of fee payment: 11 |
|
REG | Reference to a national code |
Ref country code: ES Ref legal event code: FD2A Effective date: 20001102 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20010831 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20010831 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED. Effective date: 20050831 |