EP2000003B1 - Infrared irradiation unit - Google Patents

Abstract

A high-power radiation module has thermal protection made of inorganic, oxidic material arranged between the radiator and housing. The thermal protection is made of an essentially fiber-free material that is optically inhomogeneous with respect to IR radiation and/or UV radiation The high-power radiation module has a power per unit contact area of at least 200 kW/m2. The use of a radiation module and a method for the production of a radiation module include radiators or radiation units connected electrically and held mechanically in a housing having an outlet opening for the emitted radiation.

Description

The present invention relates to high power radiator modules, in particular NIR modules. Such modules are surface radiators and usually contain at least two parallel juxtaposed infrared radiators, which have a simple round tube or a double tube. For modules with a surface power of up to 150 kW / m ² , air-cooled gold reflectors are suitable for focusing the radiation on the object to be irradiated. Connected loads of 200 kW / m ² and above can only be carried out with water-cooled reflectors, as the reflectors would otherwise be destroyed very quickly by overheating. Such provided with an additional water cooling modules are from the DE 101 56 915 or from the DE 101 25 888 known.

Elaborate water cooling is not desirable in electrical systems. Firstly, because of the additional costs and secondly because there is always the risk of water leakage. Water leakage can both damage the products to be irradiated and have disastrous consequences for the electrical equipment or the hot parts of the system. Water is therefore an extremely undesirable medium from the point of view of operational safety.

In the DE 101 56 915 In addition, ceramic fiber boards are disclosed as heat protection of the housing and as heat protection of a chamber in which the electrical leads and the cooling water hoses. These fiberboard protect the housing from stray radiation, which, despite the gold reflectors in the cooling channels, is still emitted in the direction of the module.

Also the JP 07-198949 A and the JP 05-024853 A describe IR emitters, which are provided with a heat protection.

The object of the present invention is to provide high performance radiator modules with reduced hazard potential.

Solutions to the problem are made according to the independent claims. Preferred embodiments are described in the dependent claims.

According to the invention, a heat protection which is inhomogeneous with respect to its optical density and consists of inorganic oxidic material is arranged between the radiator and the housing of a module. The heat protection according to the invention enables connection surface powers of 200 kW / m ² and more. High-power radiators with the heat protection according to the invention are extremely robust and suitable for continuous operation, ie the radiator can be operated with complete equilibrium with the environment. This equilibrium state usually sets in after 5 to 15 minutes.

Fibers are no longer necessary for the heat protection according to the invention, which is why the danger potential emanating from fiber material is eliminated according to the invention.

For producing a body, in particular monolithic sintered body, which is suitable as heat protection, in particular one-piece heat protection or as a heat protection element, the in EP 1 159 227 described method. Basically, monolithic sintered bodies of slip, such as. B. Quarzmehlschlicker, produced by sintering.

It has proven to be useful if one heat protection element or one integral heat protection is used per radiator or double-tube radiator for all radiators of a module.

• ist der Hitzeschutz oder sind die Hitzeschutzelemente ein oder jeweils ein Sinterkörper;
• weist der Hitzeschutz oder weisen die Hitzeschutzelemente Material mit einer Körnung im Nanometer- oder Mikrometerbereich auf;
• ist der Hitzeschutz oder sind die Hitzeschutzelemente ein oder jeweils ein Monolith;
• weist das Material des Hitzeschutzes oder der Hitzeschutzelemente Einschlüsse im Nanometer- oder Mikrometerbereich auf, beispielsweise Hohlräume oder Kristalle.

Especially

• is the heat protection or are the heat protection elements one or each a sintered body;
• the heat protection or the heat protection elements have material with a grain size in the nanometer or micrometer range;
• is the heat protection or are the heat protection elements one or a monolith;
• The material of the heat protection or the heat protection elements has inclusions in the nanometer or micrometer range, for example cavities or crystals.

The decisive factor is that the optical density of the heat protection varies with respect to IR radiation and possibly with respect to UV radiation, in particular in the micro range is uneven. Have to Bubbles or doping proven. In particular, the dimensions of these inclusions are less than 1 mm, preferably less than 100 μm, and more preferably less than 10 μm.

In a preferred embodiment, the heat protection which is optically inhomogeneous with respect to IR radiation consists of a material transparent to IR radiation, such as quartz glass or Al ₂ O ₃ ceramic. However, variations in the optical density, in particular by different phases within the inorganic oxide material, are formed so that these variations in the optical density of the material scatter substantial radiation components. Due to its special structure, this invention according to the invention in its optical density with respect to IR radiation or possibly UV radiation non-uniform material in the wavelength range in which a very high transparency would be achieved in homogeneous and single-phase design of the material, not the energy transfer, which Damage the case. Depending on the composition and proportion of trace impurities, this is the wavelength range from 180 nm to 5000 nm for quartz glass. The range from 180 to 400 nm, in particular 200 nm to 380 nm, is decisive for UV radiators and the range from 760 to 5000 nm. especially 780 to 4000 nm, relevant for IR emitters. This property is achieved by an optical inhomogeneity of the quartz glass, such as by targeted and homogeneous introduction of bubbles and disturbances. Alumina in pure form has a very good transmission of UV radiation to about 6000 nm out. Here, the said property is achieved by a suitable microcrystalline structure of the solid. It is surprising that the shield is applicable under conditions that metallic reflectors can no longer withstand, although the shield absorbs more radiant energy or radiant power than reflectors, but not as it thereby loses its functionality. While metallic reflectors depend in their functionality on their surface and thus lose their functionality when damaged, the functionality of the heat protection according to the invention depends on its thickness, which in contrast to the known reflectors, the rusticity of the heat protection increases with the thickness thereof.

High-performance radiator modules, which are distinguished by the fact that the heat protection arranged between radiator and housing has only one air cooling for its cooling, wherein in a preferred embodiment the air cooling additionally cools the radiator. With a simple air cooling, whose energy consumption in relation to the radiator power is negligible, for example in the percent or per thousand range, are with the heat protection according to the invention robust high-power radiator modules with a pad power from 400 to 600 KW / m ² feasible. With more complex cooling systems, connection capacities of more than 600 KW / m ^{2 are} possible, whereby even surface powers of more than 1 MW / m ² can be realized. A simple air cooling takes place for example by an air flow from a fan, a fan or a centrifugal compressor.

According to the invention, cooling with another process gas, e.g. Nitrogen or argon included. Further, the invention also encompasses the cooling with a stream of compressed air or other suitable gas, which was not generated directly by means of a centrifugal compressor, a fan or a fan, but is taken indirectly from a pressure circuit or pressure vessels, as well as any other known to the expert variant the generation of a suitable gas stream.

In an inventive development of the heat protection on the side of the case is coated with gold. This reduces the secondary radiation from the surface of a heated in operation heat protection. The radiation of the secondary radiation then takes place predominantly from the ungolded radiator-side surface.

The high-performance radiator modules equipped with the heat protection according to the invention show no deterioration of the efficiency with increasing operating time, as is known, for example, from high-power radiator modules with water-cooled reflectors.

The inorganic oxide material of the heat protection can be selected from high-temperature-stable glasses, in particular quartz glass, as well as from glass ceramics, aluminosilicate or ceramics, in particular aluminum oxide. Pure quartz glass and pure aluminum oxide ceramics have proven to be particularly suitable.

Invention vessel is provided a radiation protection, which returns much more power in the direction of the irradiating object of the radiation power directed at him, as he radiates on his back on the module and transmits. Another decisive factor is that the radiation protection does not heat up to self-destruction. With the radiation protection devices according to the invention, it is possible for the first time to provide high-power radiator modules with a connection area power of 200 watts and far beyond that without water or liquid cooling.

According to the invention, therefore, the tiresome security risk with regard to water cooling is eliminated, and the hitherto required enormous effort to minimize the risk with regard to water cooling is superfluous.

The radiation protection according to the invention is also suitable for modules with a connected load between 100 and 200 watts / m ² , in particular for the range of 150 to 200 watts / m ² in which considerable efforts are made to get along without water cooling.

The radiation protection according to the invention furthermore makes it possible to further increase the connection area power of the order of magnitude of 1 MW / m ² achievable so far with water-cooled reflectors, in particular in the case of water-cooled modules.

For high-performance applications, such as air-cooled modules with surface power from 400 watts / m ² , especially from 600 watts / m ² , optical, inhomogeneous quartz glass has proven to be radiation protection, especially in a composite with gold, in which the optical, inhomogeneous quartz glass directed to the module front is, ie in the direction of the object to be irradiated and the gold is arranged as a layer facing back on the back of the module on the optical, inhomogeneous quartz glass. Alternatively, quartz glass ceramics or ceramics glazed with quartz glass, in particular with a gold coating on the back, can be used.

For less extreme applications, such as air-cooled modules with a pad power of 100 to 300 watts / m ² , in particular 150 to 250 watts / m ² , are already high temperature stable optical, inhomogeneous glasses, such as alumino-silicate glasses, borate-silicate glasses , Alumino silicate borate glasses. In an advantageous embodiment, the back side is coated with gold or a gold reflector to spaced.

Air cooling has proved its worth by directing an air flow from the back of the module through openings in the radiation protection onto the radiators.

The emitters used according to the invention have a heating filament arranged in an envelope or a discharge space delimited in the envelope. The envelope is preferably tubular or double-tube-shaped, wherein the tube ends are sealed vacuum-tight and have current feedthroughs. The radiation maximum of the radiators is preferably in the NIR, in particular in the IR-A. The heating filament preferably consists essentially of tungsten or carbon.

For operating high-performance tungsten-based heating filaments with emitter temperatures of more than 2500 K, in particular more than 3000 K, a heat protection according to the invention between the cladding tube of the radiator and the housing holding the radiator is advantageous, in particular when using a plurality of radiators in a module.

• Figur 1 zeigt einen Querschnitt durch ein Hochleistungsmodut.
• Figur 2 zeigt einen Querschnitt einer Strahleranordnung des Moduls aus Figur 1.

In the following the invention will be clarified by means of examples with reference to figures.

• FIG. 1 shows a cross section through a high-power module.
• FIG. 2 shows a cross section of a radiator arrangement of the module FIG. 1 ,

The heat protection 3 is made of an optical, inhomogeneous quartz glass according to the Heraeus brochure "Opaque Fused Material OFM 970".

A heat protection 3 made of optically inhomogeneous quartz glass according to Heraeus brochure "Opaque Fused Material OFM 970" is coated on the housing side with gold, as already done for gold-plated cladding of infrared radiators in a known manner.

Embodiment 1

The FIG. 1 shows a module with a surface power of 400 kW / m ² , in which 6 twin tube radiator (1) arranged parallel to each other and fixed by means of holding elements (2). The heat protection elements (3) according to the invention made of optically inhomogeneous quartz glass are shaped as half shells and either fixed to the radiator tubes by glassblowing or correspondingly FIG. 1 by means of additional retaining elements (4). These half shells are arranged so that the individual emitters do not illuminate each other.

The actual module consists of a housing (11), an inlet opening for air (12) and a baffle plate (13) at which the incoming air flow is distributed in the module housing. Between the module interior and the radiator / heat shield assembly is a diffuser plate (14). This sheet is firstly the mechanical support of emitter and reflector, which can also be held elsewhere in the module. Second, holes or slots are incorporated in this diffuser plate, which serve to optimally shape the cooling gas flow. For this purpose, holes or slots in particular centrally behind the individual heat shields to be ordered. As a limitation of the radiator field additional plates from the heat shield material are arranged (15).

The FIG. 2 is an enlarged view of a section of the FIG. 1 , Shells made of OMF 70 are used as the heat shield (according to the Heraeus brochure "Opaque Fused Material OFM 70"), whereby many other quartz glasses optically inhomogeneous to IR radiation can serve as the starting material.

Embodiment 2

In a second exemplary embodiment with a surface power of 550 kW / m ² , the twin tube radiators arranged in parallel are held at their long, unheated ends and are arranged in front of a plate of optically inhomogeneous, gold-plated quartz glass. This plate consists of several segments to keep production costs low. Holes are inserted into the segments at suitable positions, so that the gas made available in the module housing by means of suitable devices flows out through these holes in such a way that the emitters are effectively blown and convectively cooled, and secondly the still cold gas flow from the housing through the heat shield this cools. The plates are made of OM100 (according to Heraeus brochure "OM 100 High purity opaque quartz glass"), although many other optically inhomogeneous quartz glasses can be used as starting material.

On the side, additional panels made of OM100 are arranged to protect the module, which are convection cooled on the back.

Embodiment 3

In a third exemplary embodiment with a surface power of 600 kW / m ² , the twin tube radiators arranged in parallel are held at their long, unheated ends. Arrangement as in Embodiment 2, but the rear heat shield consists of a plate transparent quartz glass, on which a sufficiently strong layer of optically inhomogeneous quartz was applied as a slip and subsequently sintered. This layer is aligned in the direction of the infrared radiator and gold plated the back quartz plate. Slots and holes for cooling the heat shield and the radiator are performed as in Embodiment 2, but the amount of air for cooling increased accordingly.

Claims (13)

1. A high-power radiator module, in the case of which a heat protection (3) of inorganic oxidic material is arranged between radiator (1) and housing (11), characterized in that the heat protection (3) consists of a material, which is substantially free of fibres and which is optically inhomogeneous for IR radiation and the high-power radiator module (1) encompasses a connection output per unit area of at least 200 kW/m² and the heat protection (3) is so thick that it encompasses an IR transmission of less than 10% in response to a temperature of between 0 to 1000°C.
2. The high-power radiator module according to claim 1, characterized in that the heat protection (3) encompasses only an air cooling for cooling it.
3. The high-power radiator module according to any one of claims 1 or 2, characterized in that the optically inhomogeneous oxidic material encompasses quartz glass, high-temperature stable glass, glass ceramics, aluminosilicates, ceramics.
4. The high-power radiator module according to any one of claims 1 to 3, characterized in that a cooling air stream is guided to the radiators (1) via heat protection shields.
5. The high-power radiator module according to any one of claims 1 to 4, characterized in that the heat protection (3) encompasses openings, through which the cooling air can be guided to the radiators (1).
6. The high-power radiator module according to any one of claims 1 to 5, characterized in that the material of the heat protection (3) encompasses inclusions.
7. The high-power radiator module according to any one of claims 1 to 6, characterized in that the heat protection (3) thereof encompasses material with a grain size in the nanometre or micrometre range.
8. The high-power radiator module according to any one of claims 1 to 7, characterized in that the heat protection (3) is a sinter body or encompasses a sinter body for each radiator.
9. The high-power radiator module according to any one of claims 1 to 8, characterized in that the heat protection (3) is a monolith or encompasses a monolith for each radiator.
10. A use of a radiator module according to claim 1 as water-cooled high-power radiator module comprising a connection output per unit area of at least 600 KW/m², in particular of at least 1 megawatt/m².
11. A method for producing a radiator module according to claim 1, in the case of which a plurality of radiators (1) or radiator units (1) are electrically connected and held mechanically in a housing (11) comprising an outlet opening for the emitted radiation, characterized in that a heat protection (3) of inorganic oxidic material is arranged on the side of the radiators, which face away from the outlet opening, characterized in that the heat protection (3) is optically inhomogeneous and substantially free of fibres.
12. The method for producing a radiator module according to claim 11, characterized in that a gold layer is arranged between the heat protection (3) and the housing (11), in particular by coating the heat protection with gold on the housing side.
13. A use of an inorganic oxidic heat protection (3) for a high-power radiator module according to claim 1, in particular comprising a connection output per unit area of at least 200 kW/m², characterized in that the heat protection (3) is optically inhomogeneous and substantially free of fibres.

Images