CA2068588A1 - High-power radiator - Google Patents
High-power radiatorInfo
- Publication number
- CA2068588A1 CA2068588A1 CA 2068588 CA2068588A CA2068588A1 CA 2068588 A1 CA2068588 A1 CA 2068588A1 CA 2068588 CA2068588 CA 2068588 CA 2068588 A CA2068588 A CA 2068588A CA 2068588 A1 CA2068588 A1 CA 2068588A1
- Authority
- CA
- Canada
- Prior art keywords
- radiator
- electrode
- dielectric
- electrodes
- protective layer
- 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.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J65/00—Lamps without any electrode inside the vessel; Lamps with at least one main electrode outside the vessel
- H01J65/04—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels
- H01J65/042—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels by an external electromagnetic field
- H01J65/046—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels by an external electromagnetic field the field being produced by using capacitive means around the vessel
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J65/00—Lamps without any electrode inside the vessel; Lamps with at least one main electrode outside the vessel
- H01J65/04—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels
- H01J65/042—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels by an external electromagnetic field
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Discharge Lamps And Accessories Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
In order to protect, in the case of UV-high power radiators, the electrodes (5, 3) facing the process and/or coolant from environmental effects, they are coated with a protective layer (8a).
In order to protect, in the case of UV-high power radiators, the electrodes (5, 3) facing the process and/or coolant from environmental effects, they are coated with a protective layer (8a).
Description
2 ~ 8 8 - 1 - 24.5.91/He gl/04 0 i~
,¦ TITLE OF THE INVENTION
~igh-power radiator BACKGROUND OF THE INVENTION
Field of the Invention The invention relates to a high-power radiator, in particular for ultraviolet light, having a discharge space which is filled with a filling gas emitting radia-tion under discharge conditions and whose wall~ are formed by a first and a second dielectric provided with metallic latticed or reticular first and second electro-des on its surfaces remote from the discharge space, and having an alternating-current source connected to the first and second electrodes for supplying the discharge.
In this connection, the invention proceeds from the prior art which emerges, for instance, from EP-A O 254 111.
Discus~ion o~ Backaround The industrial use of photochemical processes is heavily dependent on the availability of suitable W
sources. The conventional W radiators provide low to medium UV intensities at a few discrete wavelengths such as, for examplé, the low-pressure mercury lamps at 185 nm and, in particular at 254 nm. Really high UV powers are obtained only from high-pressure lamps (Xe, Hg) but these then distribute their radiation over a larger wavelength range. The new excimer lasers have made a few new wave-lengths available for fundamental photochemical experi-ments and are at present suitable for an industrial process probably only in exceptional cases for cost reasons.
The EP patent application mentioned in the introduction or, alternatively, the conference reprint entitled ~Neue W - und YUV- Excimerstrahler" ("New W and V W excimer radiators~) by U. Kogelschatz and B. Eliasson . . , ; ~ . , ~ . -:
.' ` - ~ , .
20~88 distributed at the Tenth Seminar of the Society of German Chemists, Specialist Group on Photochemistry, in Wurzburg ~FRG) on 18-20 November 1987, describe a new excimer radiator. This new type of radiator is based on the principle that excimer radiation can also be generated in dark electrical discharges, a type of discharge which is used on a large industrial scale in the generation of ozone. In the current filaments of this discharge, which are only present for a short time (< 1 microsecond), electron impact excite~ noble-gas atoms, which r~act further to form excited molecular complexes (excimers).
Said excimers live only for a few hundred nanoseconds and give off their bonding energy in the form of W radiati-on when they decompose.
The construction of such an excimer radiator largely corresponds to that of a conventional ozone generator including the power supply, with the essential difference that at least one of the electrodes and/or dielectric layers bounding the discharge space is trans-parent to the radiation generated. In addition to the high W transmission, said electrodes must also have, inter alia, the following properties: good electric current conductivity, low cost, good flexibility in order to produce as intimate as possible a contact with the dielectric, and long service life. The long service life reguires, in particular, a low chemical reactivity with the environment of the radiator. If it is desired to use the radiator as a light source in chemical reactors, even chemi~al inertness towards some substances is absolutely necessary for many applications.
SUMMARY OF THE INVENTION
Proceeding from the prior art, the o~ject of the invention is to provide a high-power radiator, in par-ticular for W or V W radiation, whose electrodes are ideally protected against environmental effects in addition to high W transmission.
.
~.:: . , i - .
2~6~5~
To achieve this object, provision is made, according to the invention, that at least the first electrodes are provided with a protective layer or embedded in such a layer.
A radiator having such a structure fulfills all the practical requirements:
- The electrodes exposed to the environment are protected against chemical attacks ~prolonging of the service life);
10 - The electrodes are also protected, in addition, against physical attacks: discharges cause erosion;
erosion removes electrode material which deposits on the transparent areas of the dielectric and reduces the transparency at those points;
15 _ If the environment itself is a gas or liquid to be treated with W radiation, a metallic contact with this substance is avoided in order not to initiate any additional chemical reactions in which metals are involved (chemical inertness);
20 - Any discharges (for example, Korona) in the environ-ment of the electrodes onto the dielectric or to voltage-carrying parts situated in the vicinity, or surface discharges over the dielectric are avoided by better contact with the dielectric; the better electrical insulation of the electrodes prevents, in addition, undesirable energy-consuming discharges.
The invention can be implemented practically in various ways. In addition to the mere coating of the metallic wires, for example, by immersing the electrodes in a suitable bath, the immersion of the completely assembled radiator in a bath is advantageously possible.
Coatings with so-called thick-film casting compounds which result in the advantage of an easy-to-clean outer surface of the radiator are also possible.
,¦ TITLE OF THE INVENTION
~igh-power radiator BACKGROUND OF THE INVENTION
Field of the Invention The invention relates to a high-power radiator, in particular for ultraviolet light, having a discharge space which is filled with a filling gas emitting radia-tion under discharge conditions and whose wall~ are formed by a first and a second dielectric provided with metallic latticed or reticular first and second electro-des on its surfaces remote from the discharge space, and having an alternating-current source connected to the first and second electrodes for supplying the discharge.
In this connection, the invention proceeds from the prior art which emerges, for instance, from EP-A O 254 111.
Discus~ion o~ Backaround The industrial use of photochemical processes is heavily dependent on the availability of suitable W
sources. The conventional W radiators provide low to medium UV intensities at a few discrete wavelengths such as, for examplé, the low-pressure mercury lamps at 185 nm and, in particular at 254 nm. Really high UV powers are obtained only from high-pressure lamps (Xe, Hg) but these then distribute their radiation over a larger wavelength range. The new excimer lasers have made a few new wave-lengths available for fundamental photochemical experi-ments and are at present suitable for an industrial process probably only in exceptional cases for cost reasons.
The EP patent application mentioned in the introduction or, alternatively, the conference reprint entitled ~Neue W - und YUV- Excimerstrahler" ("New W and V W excimer radiators~) by U. Kogelschatz and B. Eliasson . . , ; ~ . , ~ . -:
.' ` - ~ , .
20~88 distributed at the Tenth Seminar of the Society of German Chemists, Specialist Group on Photochemistry, in Wurzburg ~FRG) on 18-20 November 1987, describe a new excimer radiator. This new type of radiator is based on the principle that excimer radiation can also be generated in dark electrical discharges, a type of discharge which is used on a large industrial scale in the generation of ozone. In the current filaments of this discharge, which are only present for a short time (< 1 microsecond), electron impact excite~ noble-gas atoms, which r~act further to form excited molecular complexes (excimers).
Said excimers live only for a few hundred nanoseconds and give off their bonding energy in the form of W radiati-on when they decompose.
The construction of such an excimer radiator largely corresponds to that of a conventional ozone generator including the power supply, with the essential difference that at least one of the electrodes and/or dielectric layers bounding the discharge space is trans-parent to the radiation generated. In addition to the high W transmission, said electrodes must also have, inter alia, the following properties: good electric current conductivity, low cost, good flexibility in order to produce as intimate as possible a contact with the dielectric, and long service life. The long service life reguires, in particular, a low chemical reactivity with the environment of the radiator. If it is desired to use the radiator as a light source in chemical reactors, even chemi~al inertness towards some substances is absolutely necessary for many applications.
SUMMARY OF THE INVENTION
Proceeding from the prior art, the o~ject of the invention is to provide a high-power radiator, in par-ticular for W or V W radiation, whose electrodes are ideally protected against environmental effects in addition to high W transmission.
.
~.:: . , i - .
2~6~5~
To achieve this object, provision is made, according to the invention, that at least the first electrodes are provided with a protective layer or embedded in such a layer.
A radiator having such a structure fulfills all the practical requirements:
- The electrodes exposed to the environment are protected against chemical attacks ~prolonging of the service life);
10 - The electrodes are also protected, in addition, against physical attacks: discharges cause erosion;
erosion removes electrode material which deposits on the transparent areas of the dielectric and reduces the transparency at those points;
15 _ If the environment itself is a gas or liquid to be treated with W radiation, a metallic contact with this substance is avoided in order not to initiate any additional chemical reactions in which metals are involved (chemical inertness);
20 - Any discharges (for example, Korona) in the environ-ment of the electrodes onto the dielectric or to voltage-carrying parts situated in the vicinity, or surface discharges over the dielectric are avoided by better contact with the dielectric; the better electrical insulation of the electrodes prevents, in addition, undesirable energy-consuming discharges.
The invention can be implemented practically in various ways. In addition to the mere coating of the metallic wires, for example, by immersing the electrodes in a suitable bath, the immersion of the completely assembled radiator in a bath is advantageously possible.
Coatings with so-called thick-film casting compounds which result in the advantage of an easy-to-clean outer surface of the radiator are also possible.
3~ Suitable as coating or embedding material are, in particular, dielectric substances which make a good contact to the dielectric of the radiator and are at the same time easy to apply. If materials are also used in , 2068~88 this process which are W-curing, they can be extremely rapidly cured by the radiator itself.
~ Particular developments of the invention and the further advantages achieved therewith are explained in S greater detail below by reference to the drawings.
BRIEF DESCRIPTION OF TH~ DRAWINGS
A more complete sppreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by refer-ence to the following detailed description when con-sidered in connection with the accompanying drawings, wherein embodiments of h.igh-power radiators are shown in extremely simplified form; in the drawing Figure 1 shows a cylindrical W radiator of known construction;
Figure 2 shows a portion of the outer dielectric tube of a W radiator with outer electrode which is disposed thereon and composed of round wire coated with dielectric material;
Figure 3 show~ a portion of the outer dielectric tube of a W radiator with outer electrode which is disposed thereon and composed of round wire, the entire outer surface being provided with a coating material;
Figure ~ shows a portion of the outer dielectric tub~ of a UV radiator with outer electrode which is disposed thereon and composed of round wire situated in the depressions in the outer dielectric tube which are filled in their turn with coating material;
Figure 5 shows a portion of the outer dielectric tube of a UV radiator with outer electrode which is disposed thereon and is composed of round wire, with a smooth outer dielectric tube and a thick-film casting compound in which the electrodes are embedded;
- . . : . . - .
2~68~88 Figure 6 shows a portion of a UV radîator which emits radiation both outwards and inwards.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, the W high-power radiator shown diagrammatically in Figure 1 comprises an outer dielectric tube 1, for example made of quartz glass, and an inner dielectric tube 2 which is disposed concentrically therewith and whose inner wall is provided with an inner electrode 3. The annular space between the two tubes 1 and 2 forms the discharge space 4 of the radiator. The inner tube 2 is inserted in a gastight manner into the outer tube 1, which has previously been filled with a gas or gas mixture which emits W or VUV
radiation under the influence of dark electric discharges.
The outer electrode 5 used is a metal net or metal lattice which extends over the entire circumference of the outer tub~ 1. Both the outer electrode 5 and the outer dielectric tube 1 are transparent to the W ra-diation generated.
The electrodes 3 and 5 are routed to the two poles of an alternating-current source 6. The alternat-ing-current source basically corresponds to those such as are used to feed ozone generators. Typically it delivers an adjustable alternating voltage in the order or mag-nitude of several 100 volts to 20,000 volts at frequen-cies in the range of industrial alternating current up to - 30 and including a few 1000 k~z, depending on the electrode geometry, pressuxe in the discharge space 4 and composi-tion of the illing gas.
The filling gas is, for example, mercury, noble gas, noble gas/metal vapor mixture, noble gas/halogen mixture, optionally with the use of an additional further noble gas, preferably Ar, He, Ne, as buffer gas.
2~6~88 Depending on the desired spectral composition of the radiation, a substance/substance mixture in accordance with the table below may be used in this connection:
5 Fillinq qas Radiation Helium 60 - 100 nm Neon 80 - 90 mn Argon 107 - 165 nm Argon + fluorine 180 - 200 nm Argon + chlorine 165 - 190 nm Argon + krypton + chlorine 165 - 190, 200-240 nm Xenon. 160 - 190 nm Nitrogen 337 - 415 nm Xrypton 124, 140 - 160 nm Krypton + fluorine 240 - 255 nm Krypton + chlorine 200 - 240 nm Mercury 185, 254, 320-370, 390-420 nm Selenium 196, 204, 206 nm Deuterium 150 - 250 nm Xenon + fluorine 340 - 360 nm, 400-550 nm Xenon + chlorine 300 - 320 nm In addition, a whole of number of further filling gases are possible:
- a noble gas (~r, He, Kr, Ne, Xe) or Hg with a gas or vapor composed of F2, I2, Br2, C12 or a compound which releases one or more F, I, Br or Cl atoms in the discharge;
- a noble gas (Ar, He, Kr, Ne, Xe) or Hg with 2 or a compound which releases one or more O atoms in the discharge;
- a noble gas (Ar, He, Kr, Ne, Xe) with Hg.
In the dark electric discharge (silent discharge) which forms, the electron energy distribution can be ideally adjusted by the thickness of the dielectrics and their properties and the pressure andJor temperature in the discharge space.
When an alternating voltage is applied between the electxodes 3, 5, a multiplicity of discharge channels ~,, (partial discharges) forms in the discharge space 4.
These interact with the atoms/molecules of the filling - gas, and this ultimately results in W or VUV radiation.
In the portion shown in Figure 2, the individual wires 7 of the outer electrode are provided with a coating 8. In the simplest case, this may be composed of wire enamel. Such insulated wires with baked enamel are standard in transformer construction. Depending on the enamel thickness and the type of enamel, the additional voltage advantage due to the enamel can be optimized with respect to the voltage of the discharge.
In the portion shown in Figure 3, not only the wire but the entire radiator surfa~e is provided with a coating 8a of clear enamel. Although this arrangement reduces the W radiator output of some wavelengths, it can be produced particularly easily by immersing the completely assembled radiator in a bath of enamel, or by spraying on an enamel or, alternatively, by brushing it on and then curing it. For a 308 nm radiation and a typical layer thickness of 1 to 2 ~m, the transmission is in this case more than 80%. Preferably, UV-curiny clear enamels are used in this process which can be cured extremely rapidly by the radiator itself and for which the transmission improves after the curing because of the chemical transformation.
In the arrangement shown in Figure 4, the in-dividual wires 7 of the outer electrode 5 are situated in depressions in the outer dielectric tube 1 and are completely embedded in the coating 8b, for example a clear enamel. The enamel layer ~b then has alternately varying thickness along the radiator surface. Since thin enamel layers transmit the UV radiation generated better than thick ones, a corresponding intensity pattern is produced. This is of advantage for applications in which an object which is to be W-irradiated is moved along the surface and well-defined exposure intervals are to occur.
Finally, Figure 5 illustrates the arrangement of wires compl~tely embedded in a W-transparent thick-film 20~8~88 casting compound ~c on a smooth outer dielectric tube l.
The modern development of W-curing products has made it;
possible to produce such casting compounds from clear enamel and even pigmented systems. Examples of UV-curing epoxy resins and UV-curing acrylates are described, for example, in the lecture manuscript of the Panacol-Elosol GmbH company entitled " W-E~OXIES - Neue Moglichkeiten mit strahlungshartenden Klebstoffen und Vergussmassen"
("UV-EXPOXIES - New possibilities using radiation-curing adhe~ives and casting compounds"), Hau~ der Technik e.V., Essen dated 20.11.1990. In such an arrangement, the "base" of the casting compound 8c, the outer dielectric tube 1, can be of thinner construction and in the limit case can even be omitted if the dielectric properties of the casting compound are matched to the discharge process.
The rearrangement, according to the invention, of the electrodes can be used successfully not only in cylindrical radiators but also in two-dimensional radia-tors. The outer electrodes themselves may also be of different design, for example not reticular or latticed, but con isting only of parallel strips, and this suggests itself, in particular, in an arrangement as shown in Figure 3.
Instead of separate or discrete electrode arrangements, those which are deposited by strip-type or lattice/reticular metallizations on the outer surface of the dielectric tube 1 and are then provided with a coating using the process described in connection with Figure 3 can also be used.
The invention was explained a~ove by reference to exemplary embodiments which relate to so-called outward radiators. The measureg of protecting the electrodes disclosed in this connection also apply, of course, to a so-called inward radiator. Apart from the position of the transparent electrodes 5, such an inward radiator corresponds to the outward radiator shown in Figure l.
-. ;~
2~68~88 _ 9 _ Furthermore, radiator configurations are also possible in which the UV radiation is radiated both ~ outwards and inwards. Figure 6 illustrates a portion of such a radiator. In such arrangements, both dielectric tubes 1, 2 and also the respective electrodes 3, 5 have to be transparent to the radiation generated. In this cas~, both the first electrodes 5 and the second elec-trodes 3 can be ideally protected against chemical and physical attacks in the way described above.
Outward and inward radiators are norm~lly cooled with a liquid coolant. In outward radiators, this is passed through the inner dielectric tube 2 and in inward radiators the coolant flows round the outer dielectric tube 1. Here, again, protective layers composed of the materials described contribute to preventing the erosive attack by the coolant or at least to reducing it. Insofar as electrodes are involved in this connection which must not transmit any W radiation, other protective layers may also be used, for example those applied by anodizing, enameling etc. In the case of aluminum electrodes vapor-deposited or sputtered onto the dielectric, anodization of the free surface suggests itself. In the case of reticular or latticed electrodes which must not transmit any UV xadiation, care must be taken that no (external) discharges occur between electrode and dielectric sur-face, which may take place as a result of filling the gap with an enamel or other fillers such as adhesive or nonconducting or conducting pastes, for ex~mple fluid s Llver .
Obviously, numerous modifications and variations - of the present invention are possible in light of the above teachings. It is therefore to be understood that wi~hin the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
,;; ,,~ .
., . .. . ~ .
~ Particular developments of the invention and the further advantages achieved therewith are explained in S greater detail below by reference to the drawings.
BRIEF DESCRIPTION OF TH~ DRAWINGS
A more complete sppreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by refer-ence to the following detailed description when con-sidered in connection with the accompanying drawings, wherein embodiments of h.igh-power radiators are shown in extremely simplified form; in the drawing Figure 1 shows a cylindrical W radiator of known construction;
Figure 2 shows a portion of the outer dielectric tube of a W radiator with outer electrode which is disposed thereon and composed of round wire coated with dielectric material;
Figure 3 show~ a portion of the outer dielectric tube of a W radiator with outer electrode which is disposed thereon and composed of round wire, the entire outer surface being provided with a coating material;
Figure ~ shows a portion of the outer dielectric tub~ of a UV radiator with outer electrode which is disposed thereon and composed of round wire situated in the depressions in the outer dielectric tube which are filled in their turn with coating material;
Figure 5 shows a portion of the outer dielectric tube of a UV radiator with outer electrode which is disposed thereon and is composed of round wire, with a smooth outer dielectric tube and a thick-film casting compound in which the electrodes are embedded;
- . . : . . - .
2~68~88 Figure 6 shows a portion of a UV radîator which emits radiation both outwards and inwards.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, the W high-power radiator shown diagrammatically in Figure 1 comprises an outer dielectric tube 1, for example made of quartz glass, and an inner dielectric tube 2 which is disposed concentrically therewith and whose inner wall is provided with an inner electrode 3. The annular space between the two tubes 1 and 2 forms the discharge space 4 of the radiator. The inner tube 2 is inserted in a gastight manner into the outer tube 1, which has previously been filled with a gas or gas mixture which emits W or VUV
radiation under the influence of dark electric discharges.
The outer electrode 5 used is a metal net or metal lattice which extends over the entire circumference of the outer tub~ 1. Both the outer electrode 5 and the outer dielectric tube 1 are transparent to the W ra-diation generated.
The electrodes 3 and 5 are routed to the two poles of an alternating-current source 6. The alternat-ing-current source basically corresponds to those such as are used to feed ozone generators. Typically it delivers an adjustable alternating voltage in the order or mag-nitude of several 100 volts to 20,000 volts at frequen-cies in the range of industrial alternating current up to - 30 and including a few 1000 k~z, depending on the electrode geometry, pressuxe in the discharge space 4 and composi-tion of the illing gas.
The filling gas is, for example, mercury, noble gas, noble gas/metal vapor mixture, noble gas/halogen mixture, optionally with the use of an additional further noble gas, preferably Ar, He, Ne, as buffer gas.
2~6~88 Depending on the desired spectral composition of the radiation, a substance/substance mixture in accordance with the table below may be used in this connection:
5 Fillinq qas Radiation Helium 60 - 100 nm Neon 80 - 90 mn Argon 107 - 165 nm Argon + fluorine 180 - 200 nm Argon + chlorine 165 - 190 nm Argon + krypton + chlorine 165 - 190, 200-240 nm Xenon. 160 - 190 nm Nitrogen 337 - 415 nm Xrypton 124, 140 - 160 nm Krypton + fluorine 240 - 255 nm Krypton + chlorine 200 - 240 nm Mercury 185, 254, 320-370, 390-420 nm Selenium 196, 204, 206 nm Deuterium 150 - 250 nm Xenon + fluorine 340 - 360 nm, 400-550 nm Xenon + chlorine 300 - 320 nm In addition, a whole of number of further filling gases are possible:
- a noble gas (~r, He, Kr, Ne, Xe) or Hg with a gas or vapor composed of F2, I2, Br2, C12 or a compound which releases one or more F, I, Br or Cl atoms in the discharge;
- a noble gas (Ar, He, Kr, Ne, Xe) or Hg with 2 or a compound which releases one or more O atoms in the discharge;
- a noble gas (Ar, He, Kr, Ne, Xe) with Hg.
In the dark electric discharge (silent discharge) which forms, the electron energy distribution can be ideally adjusted by the thickness of the dielectrics and their properties and the pressure andJor temperature in the discharge space.
When an alternating voltage is applied between the electxodes 3, 5, a multiplicity of discharge channels ~,, (partial discharges) forms in the discharge space 4.
These interact with the atoms/molecules of the filling - gas, and this ultimately results in W or VUV radiation.
In the portion shown in Figure 2, the individual wires 7 of the outer electrode are provided with a coating 8. In the simplest case, this may be composed of wire enamel. Such insulated wires with baked enamel are standard in transformer construction. Depending on the enamel thickness and the type of enamel, the additional voltage advantage due to the enamel can be optimized with respect to the voltage of the discharge.
In the portion shown in Figure 3, not only the wire but the entire radiator surfa~e is provided with a coating 8a of clear enamel. Although this arrangement reduces the W radiator output of some wavelengths, it can be produced particularly easily by immersing the completely assembled radiator in a bath of enamel, or by spraying on an enamel or, alternatively, by brushing it on and then curing it. For a 308 nm radiation and a typical layer thickness of 1 to 2 ~m, the transmission is in this case more than 80%. Preferably, UV-curiny clear enamels are used in this process which can be cured extremely rapidly by the radiator itself and for which the transmission improves after the curing because of the chemical transformation.
In the arrangement shown in Figure 4, the in-dividual wires 7 of the outer electrode 5 are situated in depressions in the outer dielectric tube 1 and are completely embedded in the coating 8b, for example a clear enamel. The enamel layer ~b then has alternately varying thickness along the radiator surface. Since thin enamel layers transmit the UV radiation generated better than thick ones, a corresponding intensity pattern is produced. This is of advantage for applications in which an object which is to be W-irradiated is moved along the surface and well-defined exposure intervals are to occur.
Finally, Figure 5 illustrates the arrangement of wires compl~tely embedded in a W-transparent thick-film 20~8~88 casting compound ~c on a smooth outer dielectric tube l.
The modern development of W-curing products has made it;
possible to produce such casting compounds from clear enamel and even pigmented systems. Examples of UV-curing epoxy resins and UV-curing acrylates are described, for example, in the lecture manuscript of the Panacol-Elosol GmbH company entitled " W-E~OXIES - Neue Moglichkeiten mit strahlungshartenden Klebstoffen und Vergussmassen"
("UV-EXPOXIES - New possibilities using radiation-curing adhe~ives and casting compounds"), Hau~ der Technik e.V., Essen dated 20.11.1990. In such an arrangement, the "base" of the casting compound 8c, the outer dielectric tube 1, can be of thinner construction and in the limit case can even be omitted if the dielectric properties of the casting compound are matched to the discharge process.
The rearrangement, according to the invention, of the electrodes can be used successfully not only in cylindrical radiators but also in two-dimensional radia-tors. The outer electrodes themselves may also be of different design, for example not reticular or latticed, but con isting only of parallel strips, and this suggests itself, in particular, in an arrangement as shown in Figure 3.
Instead of separate or discrete electrode arrangements, those which are deposited by strip-type or lattice/reticular metallizations on the outer surface of the dielectric tube 1 and are then provided with a coating using the process described in connection with Figure 3 can also be used.
The invention was explained a~ove by reference to exemplary embodiments which relate to so-called outward radiators. The measureg of protecting the electrodes disclosed in this connection also apply, of course, to a so-called inward radiator. Apart from the position of the transparent electrodes 5, such an inward radiator corresponds to the outward radiator shown in Figure l.
-. ;~
2~68~88 _ 9 _ Furthermore, radiator configurations are also possible in which the UV radiation is radiated both ~ outwards and inwards. Figure 6 illustrates a portion of such a radiator. In such arrangements, both dielectric tubes 1, 2 and also the respective electrodes 3, 5 have to be transparent to the radiation generated. In this cas~, both the first electrodes 5 and the second elec-trodes 3 can be ideally protected against chemical and physical attacks in the way described above.
Outward and inward radiators are norm~lly cooled with a liquid coolant. In outward radiators, this is passed through the inner dielectric tube 2 and in inward radiators the coolant flows round the outer dielectric tube 1. Here, again, protective layers composed of the materials described contribute to preventing the erosive attack by the coolant or at least to reducing it. Insofar as electrodes are involved in this connection which must not transmit any W radiation, other protective layers may also be used, for example those applied by anodizing, enameling etc. In the case of aluminum electrodes vapor-deposited or sputtered onto the dielectric, anodization of the free surface suggests itself. In the case of reticular or latticed electrodes which must not transmit any UV xadiation, care must be taken that no (external) discharges occur between electrode and dielectric sur-face, which may take place as a result of filling the gap with an enamel or other fillers such as adhesive or nonconducting or conducting pastes, for ex~mple fluid s Llver .
Obviously, numerous modifications and variations - of the present invention are possible in light of the above teachings. It is therefore to be understood that wi~hin the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
,;; ,,~ .
., . .. . ~ .
Claims (6)
1. A high-power radiator, in particular for ultra-violet light, having a discharge space (4) which is filled with a filling gas emitting radiation under discharge conditions and whose walls are formed by a first and a second dielectric (1, 2) provided with a metallic latticed or reticular first (5) and second electrode (3) on its surfaces remote from the discharge space (4), and having an alternating-current source (6) connected to the first and second electrode for supplying the discharge, wherein at least the first electrodes (5) are provided with a protective layer (8; 8a; 8b; 8c) or are embedded in such a layer.
2. The high-power radiator as claimed in claim 1, wherein only the material of which the electrode (5, 3) is made is provided with a protective layer (8), prefer-ably of wire enamel (Figure 2).
3. The high-power radiator as claimed in claim 1, wherein at least the first electrode (5) and at least the surface of the first dielectric (1) in the region of this electrode are provided with a UV-transparent protective layer (8a) (Figure 3).
4. The high-power radiator as claimed in claim 1 or 2, wherein the outer surface of the first dielectric (1) and/or the inner surface of the second dielectric (2) are/is provided with regular depressions in which the electrodes (5, 3) are at least partially embedded and the depressions are filled with a UV-transparent compound (8b) which covers the electrodes (5, 3) completely.
5. The high-power radiator as claimed in claim 1 or 3, wherein at least the first electrode (5) is embedded in a protective layer (8c) composed of a UV-transparent casting compound.
6. The high-power radiator as claimed in one of claims 1 to 5, wherein the protective layer is a UV-curing enamel, adhesive or casting compound which is cured by the radiator itself.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP91108604A EP0515711A1 (en) | 1991-05-27 | 1991-05-27 | High power radiator |
| EP91108604.9 | 1991-05-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2068588A1 true CA2068588A1 (en) | 1992-11-28 |
Family
ID=8206776
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2068588 Abandoned CA2068588A1 (en) | 1991-05-27 | 1992-05-13 | High-power radiator |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0515711A1 (en) |
| JP (1) | JPH05174792A (en) |
| CA (1) | CA2068588A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022023613A1 (en) * | 2020-07-28 | 2022-02-03 | Oozbein Biohigiene, Sociedad Limitada | Ozone-generating bulb |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE9405142U1 (en) * | 1994-03-25 | 1994-06-23 | Brand-Erbisdorfer Lichtquellenproduktions- und Vertriebsgesellschaft mbH, 09618 Brand-Erbisdorf | Transmitter for introducing electrical energy into gas discharge lamps |
| DE19843419A1 (en) * | 1998-09-22 | 2000-03-23 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Discharge lamp suited for operation by dielectrically obstructed discharge has part of electrodes covered with dielectric layer additionally covered directly with blocking layer between each electrode and dielectric layer. |
| US6727649B1 (en) | 1999-11-10 | 2004-04-27 | Harison Toshiba Lighting Corporation | Fluorescent lamp, discharge lamp and liquid crystal backlight device incorporating this |
| US20070210713A1 (en) * | 2004-04-08 | 2007-09-13 | Sen Engineering Co., Ltd. | Dielectric Barrier Discharge Excimer Light Source |
| JP5600590B2 (en) * | 2008-06-19 | 2014-10-01 | ベイジン ティアンヤン プタイ インベストメント アンド コンサルティング カンパニー リミテッド | Power-saving high-intensity integrated fluorescent lamp |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1128880A (en) * | 1966-09-16 | 1968-10-02 | Gen Electric | Improvements in metal bonding |
| US4279590A (en) * | 1976-06-23 | 1981-07-21 | Gte Products Corporation | Lamp with protective coating and method of applying same |
| US4427923A (en) * | 1981-10-01 | 1984-01-24 | Gte Laboratories Inc. | Electrodeless fluorescent light source |
| NL8205025A (en) * | 1982-12-29 | 1984-07-16 | Philips Nv | GAS DISCHARGE LAMP. |
| JPS62262361A (en) * | 1986-05-07 | 1987-11-14 | Canon Inc | Flat light source device |
| CH670171A5 (en) * | 1986-07-22 | 1989-05-12 | Bbc Brown Boveri & Cie | |
| JPH079796B2 (en) * | 1987-03-28 | 1995-02-01 | 東芝ライテック株式会社 | Discharge lamp |
| CH675178A5 (en) * | 1987-10-23 | 1990-08-31 | Bbc Brown Boveri & Cie | |
| CH676168A5 (en) * | 1988-10-10 | 1990-12-14 | Asea Brown Boveri |
-
1991
- 1991-05-27 EP EP91108604A patent/EP0515711A1/en not_active Withdrawn
-
1992
- 1992-05-13 CA CA 2068588 patent/CA2068588A1/en not_active Abandoned
- 1992-05-27 JP JP13484092A patent/JPH05174792A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022023613A1 (en) * | 2020-07-28 | 2022-02-03 | Oozbein Biohigiene, Sociedad Limitada | Ozone-generating bulb |
| ES2893247A1 (en) * | 2020-07-28 | 2022-02-08 | Oozbein Biohigiene Sl | Ozone generating light bulb (Machine-translation by Google Translate, not legally binding) |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0515711A1 (en) | 1992-12-02 |
| JPH05174792A (en) | 1993-07-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |