WO2024251346A1 - Metal workpiece which can be oxidized, method for thermally generating an oxide layer of the metal workpiece which can be oxidized, and irradiating assembly for irradiating a fluid with ultraviolet radiation - Google Patents

Abstract

The invention relates to a metal workpiece (100) which can be oxidized. The metal workpiece (100) which can be oxidized has a thermally generated oxide layer (101) on at least one workpiece surface. The oxide layer (101) is designed to absorb at least part of an ultraviolet radiation (103) which is incident on the workpiece that can be oxidized and at least reduce the reflection of the ultraviolet radiation (105) reflected by the oxide layer (101). The oxide layer (101) has a composition of different metal oxides which are designed to absorb a specific light wavelength range of the ultraviolet radiation (103) which is incident on the metal workpiece (100) which can be oxidized.

Description

OXIDIZABLE METALLIC WORKPIECE, METHOD FOR THERMAL PRODUCTION OF AN OXIDE LAYER OF THE OXIDIZABLE METALLIC WORKPIECE AND IRRADIATION ARRANGEMENT

FOR IRRADIATION OF A FLUID WITH ULTRAVIOLET RADIATION

The invention relates to an oxidizable metallic workpiece, a method for thermally producing an oxide layer of the oxidizable metallic workpiece and

5 an irradiation arrangement for irradiating a fluid with ultraviolet radiation, wherein the irradiation arrangement comprises a radiation filter with the oxidizable metallic workpiece.

When using artificial ultraviolet radiation or under the influence of natural ultraviolet radiation, it is typically desirable to limit the range of action of the ultraviolet radiation, for example to protect downstream material and/or living beings, especially persons, since ultraviolet radiation is harmful to health, especially in persons.

15 The present invention is based on the object of providing an efficient workpiece for reducing the intensity of ultraviolet radiation.

This object is achieved by the features of the independent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the

20 Description and the accompanying figures.

According to a first aspect, the object of the invention is achieved by an oxidizable metallic workpiece, wherein the oxidizable metallic workpiece has a thermally generated oxide layer on at least one workpiece surface,

25 wherein the oxide layer is designed to at least partially absorb ultraviolet radiation incident on the oxidizable workpiece and to at least reduce reflection of the ultraviolet radiation reflected by the oxide layer, wherein the oxide layer has a composition of different metal oxides which are designed to absorb a predetermined light wavelength range of the ultraviolet radiation incident on the oxidizable metallic workpiece.

As a result, the oxidizable metallic workpiece (hereinafter also referred to as workpiece) can have a specific composition of metal oxides which have advantageous absorption properties in the predetermined

35 light wavelength range. This effectively reduces the potentially harmful ultraviolet radiation emitted by the workpiece. By adjusting the composition of the different metal oxides, in particular at least two different metal oxides, the absorbing light wavelength range of the ultraviolet radiation can be effectively adjusted.

The oxide layer can be distributed homogeneously on the at least one workpiece surface. The oxide layer can completely cover the at least one workpiece surface.

In one embodiment, the composition of different metal oxides is an optimal composition of different metal oxides. The optimal composition of different metal oxides can, for example, be correlated with a minimum range, in particular a minimum, of a wavelength-dependent reflectivity of the oxide layer in the predetermined light wavelength range.

In one embodiment, the oxidizable metallic workpiece comprises iron, chromium and/or nickel, in particular steel according to one of the DIN standards 1.4301 or 1.4307 or 1.0503 or 1.4404.

In one embodiment, the metal oxides comprise iron oxide, chromium oxide and/or nickel oxide.

The proportion of iron oxide in the oxide layer can in particular be more than 90 percent by volume, preferably more than 95 percent by volume and more preferably more than 99 percent by volume based on the total volume of the oxide layer.

The proportion of chromium oxide and/or nickel oxide in the oxide layer can in particular be less than 10 percent by volume, preferably less than 5 percent by volume and more preferably less than 1 percent by volume based on the total volume of the oxide layer.

In one embodiment, the metal oxides of the oxide layer comprise magnetite (FeaO^) and hematite (Fe2O3).

In one embodiment, the ratio of magnetite to hematite is between 10 volume percent magnetite to 90 volume percent hematite to 70 volume percent magnetite to 30 volume percent hematite based on the total volume of the Oxide layer, in particular between 20 volume percent magnetite to 80 volume percent hematite to 50 volume percent magnetite to 50 volume percent hematite.

A corresponding volume ratio results in an oxide layer which is particularly suitable for the absorption of ultraviolet radiation in the predetermined light wavelength range.

In one embodiment, the oxide layer is designed to reflect a radiation component in a wavelength range from 560 nm to 650 nm.

As a result, the oxide layer can have a yellow, golden yellow, yellow-brown or brown-red color, and thus be characteristically identifiable for a user.

In one embodiment, the predetermined wavelength of ultraviolet radiation absorbed by the metal oxides is between 240 nm and 295 nm, preferably between 250 nm and 285 nm, more preferably between 252 nm and 256 nm.

As a result, the oxide layer can particularly effectively absorb ultraviolet radiation in a light wavelength range that is common in air disinfection, for example. For example, the oxide layer can be adjusted to the radiation ranges of UV LEDs, in particular UV-C LEDs, and/or to the radiation ranges of UV fluorescent lamps, in particular UV-C fluorescent lamps.

In one embodiment, the predetermined wavelength of ultraviolet radiation absorbed by the metal oxides is between 340 nm to 470 nm, preferably between 360 nm to 380 nm.

As a result, the oxide layer can particularly effectively absorb ultraviolet radiation in a light wavelength range that is common in the curing of adhesives. For example, the oxide layer can be adjusted to radiation ranges of UV LEDs, in particular UV-A LEDs, and/or to radiation ranges of UV fluorescent lamps, in particular UV-A fluorescent lamps.

In one embodiment, a ratio of an intensity of the ultraviolet radiation reflected by the oxide layer to an intensity of the ultraviolet radiation reflected on the oxide layer incident ultraviolet radiation, in particular in a light wavelength range of 250 nm to 280 nm and/or 280 nm to 330 nm, less than 15%, in particular less than 10%.

This enables an effective reduction in the intensity of the reflected ultraviolet radiation to be achieved compared to a workpiece without an oxide layer.

In one embodiment, a ratio of an intensity of the ultraviolet radiation reflected by the oxide layer to an intensity of the ultraviolet radiation incident on the oxide layer, in particular in a light wavelength range from 330 nm to 400 nm, is less than 20%, in particular less than 15%.

This enables an effective reduction in the intensity of the reflected ultraviolet radiation to be achieved compared to a workpiece without an oxide layer.

In one embodiment, a ratio of an intensity of further radiation reflected by the oxide layer to an intensity of the further radiation incident on the oxide layer in a light wavelength range from 400 nm to 500 nm is more than 10%, in particular more than 12%, and/or in a light wavelength range from 500 nm to 600 nm more than 20%, in particular more than 25%, and/or in a light wavelength range from 600 nm to 800 nm more than 35%, in particular more than 40%.

This means that the workpiece can be used in arrangements for indirect lighting, thus ensuring sufficient reflection of additional radiation. The additional radiation can be, for example, daylight or artificially generated light.

In one embodiment, a layer thickness of the oxide layer is between 50nm and 1000pm, in particular between 100nm and 500pm.

The effectiveness of the oxide layer can be increased by the layer thickness.

In one embodiment, the oxidizable metallic workpiece is designed as a plate. In particular, the oxidizable metallic workpiece can be designed as a sheet. In particular, a thickness of the sheet or plate can be between 0.1 mm and 0.3 mm. In one embodiment, the oxidizable metallic workpiece designed as a plate is wave-shaped, in particular waves of the wave-shaped oxidizable metallic workpiece extend along at least one extension direction of the oxidizable metallic workpiece.

In one embodiment, a shape of the oxidizable metallic workpiece is at least partially formed by one of the following manufacturing processes: machining processes, in particular milling, turning, drilling, countersinking, rubbing, planing, broaching, reaming, sawing, filing, rasping, brush cutting, grinding, jet cutting, honing or primary forming processes, in particular casting, sintering, 3D printing, laser sintering, or forming processes, in particular bending, extrusion, upsetting, embossing, countersinking, piercing, deep drawing, collar drawing, cold forming, cold rolling, warm and hot forming, warm and hot rolling, punching, forging, or joining processes, in particular assembling, pressing and pressing in, primary forming, forming, fusion welding, pressure welding, soldering, gluing.

The oxidizable metallic workpiece can thus be manufactured in an application-specific form using any manufacturing process, in particular with machining processes such as milling, turning, drilling, countersinking, grinding, planing, broaching, reaming, sawing, filing, rasping, brushing, grinding, jet cutting, honing or with primary forming processes such as casting, sintering, 3D printing, laser sintering or with forming processes such as bending, extrusion, upsetting, embossing, countersinking, piercing, deep drawing, collar drawing, cold forming, cold rolling, warm and hot forming, punching, forging or with joining processes such as assembling, pressing and pressing in, primary forming, forming, fusion welding, pressure welding, soldering, gluing. The workpiece surface of the workpiece can therefore have any shape and surface finish.

In one embodiment, the oxide layer is resistant to ultraviolet radiation.

This means that the oxide layer of the workpiece can be used particularly efficiently to reduce the intensity of ultraviolet radiation.

In one embodiment, the oxidizable metallic workpiece is resistant to corrosion and/or intergranular corrosion, in particular according to the DIN standards DIN EN ISO 3651-2 and/or DIN EN ISO 9227. This means that the oxide layer of the workpiece can be used particularly efficiently to reduce the intensity of ultraviolet radiation in operating rooms or to protect people.

According to a second aspect, the object of the invention is achieved by a thermal method for producing the oxide layer of the oxidizable workpiece according to the first aspect, the method comprising: heating the oxidizable metallic workpiece for a predetermined duration and a predetermined temperature while supplying a predetermined amount of gas with a predetermined oxygen content in order to obtain an oxide layer on a material surface of the oxidizable metallic workpiece, which oxide layer is designed to at least partially absorb ultraviolet radiation incident on the oxidizable workpiece and to at least reduce reflection of the ultraviolet radiation reflected by the oxide layer, the oxide layer having a composition of different metal oxides which are designed to absorb a predetermined light wavelength range of the ultraviolet radiation incident on the oxidizable metallic workpiece.

The predetermined oxygen content can in particular be between 19% and 23% based on the total volume of the gas.

In one embodiment, the method further comprises: determining the predetermined duration and/or the predetermined temperature prior to the step of heating the oxidizable metallic workpiece; and/or determining the predetermined amount of oxygen prior to the step of heating the oxidizable metallic workpiece.

This makes it possible to determine precisely the predetermined duration, the predetermined temperature and/or the predetermined amount of oxygen for heating, which achieves an advantageous layer thickness and/or composition of the oxide layer of the workpiece. The predetermined duration, the predetermined temperature and/or the predetermined amount of oxygen can be determined, for example, via reference experiments.

According to a third aspect, the object of the invention is achieved by an irradiation arrangement for irradiating a fluid with ultraviolet radiation, comprising: a housing with a housing interior, wherein the housing is designed to guide the fluid in the housing interior along a flow direction, wherein the housing has a fluid inlet side which is designed to receive the fluid, and a fluid outlet side which is designed to discharge the fluid, wherein the fluid is guided through the housing from the fluid inlet side to the fluid outlet side; a lighting means which is arranged in the housing interior between the fluid inlet side and the fluid outlet side and is designed to irradiate the fluid guided through the housing with ultraviolet radiation; and a radiation filter which is arranged on the fluid inlet side or fluid outlet side on or in the housing and is designed to reduce the intensity of ultraviolet radiation emerging on the fluid inlet side or fluid outlet side; wherein the radiation filter comprises an oxidizable metallic workpiece according to the first aspect.

This achieves the technical advantage that microorganisms in the fluid are exposed to ultraviolet radiation in the housing interior along the flow direction through the housing interior. The ultraviolet radiation emitted by the light source can reach an irradiation intensity within the housing interior to inactivate, for example, 99.9999% of the microorganisms in the housing interior (according to a Log 6 reduction in microorganisms, suitable for the operating room) by irradiation. Efficient irradiation can therefore take place just by passing the fluid through the housing interior once. The radiation filter and the workpiece can reduce the intensity of the ultraviolet radiation on the fluid inlet side or fluid outlet side, so that the intensity of the ultraviolet radiation outside the housing of the irradiation arrangement can be reduced.

Fluids are gases, for example ambient air, or liquids, for example water. In one embodiment, the fluid is a gas or gas mixture, for example ambient air.

In one embodiment, the radiation filter further comprises a further oxidizable metallic workpiece according to the first aspect, wherein the oxidizable metallic workpiece and the further oxidizable metallic workpiece are spaced apart from one another. As a result, ultraviolet radiation can be reflected multiple times between the oxidizable metallic workpiece and the other oxidizable metallic workpiece, whereby a particularly advantageous reduction in the intensity of the ultraviolet radiation can be achieved.

In one embodiment, the respective oxide layers of the oxidizable metallic workpieces face each other and/or the oxidizable metallic workpieces are wave-shaped.

Due to the oxide layers facing each other, ultraviolet radiation can be reflected multiple times between the oxidizable metallic workpiece and the other oxidizable metallic workpiece, even if the oxide layers are arranged on one side of the corresponding workpieces, whereby a particularly advantageous reduction in the intensity of the ultraviolet radiation can be achieved.

The wave-shaped shape of the workpieces can increase the probability of multiple reflection of the ultraviolet radiation, which can achieve a particularly advantageous reduction in the intensity of the ultraviolet radiation down to risk class 0 according to IEC 62471 “exempt group”.

The embodiments mentioned for the subject matter of the first aspect are also embodiments for the subject matter of the second aspect and the third aspect.

The embodiments mentioned for the subject matter of the second aspect are also embodiments for the subject matter of the first aspect and the third aspect.

The embodiments mentioned for the subject matter of the third aspect are also embodiments for the subject matter of the first aspect and the second aspect.

The invention is described in more detail below using exemplary embodiments and the figures. The figures show:

Fig. 1a is a side view of an oxidizable metallic workpiece according to an embodiment; Fig. 1b is a side view of an oxidizable metallic workpiece according to another embodiment;

Fig. 1c is a cross-section of an oxidizable metallic workpiece according to another embodiment;

Fig. 2 shows a method for the thermal production of an oxide layer of an oxidizable workpiece according to an embodiment;

Fig. 3 is a diagram showing a heating curve of a temperature during a method for producing an oxide layer of a workpiece according to an embodiment;

Fig. 4 is a diagram with measurement results of a reflectivity of a workpiece according to an embodiment as a function of a residual radiation intensity;

Fig. 5a is a diagram with measurement results of a reflectivity of a workpiece according to an embodiment as a function of a wavelength of radiation applied to the workpiece;

Fig. 5b is a diagram with measurement results of a reflectivity of a workpiece according to an embodiment as a function of a wavelength of radiation applied to the workpiece;

Fig. 6a is a side view of a radiation filter in cross section with a workpiece according to an embodiment and another workpiece according to an embodiment;

Fig. 6b is another view of a radiation filter with a plurality of workpieces according to an embodiment;

Fig. 6c is another view of a radiation filter with a plurality of workpieces according to an embodiment; and

Fig. 7 is a view of a radiation filter in an irradiation arrangement according to an embodiment. In the following description, reference is made to the accompanying figures which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense. Furthermore, it is to be understood that the features of the various embodiments described herein may be combined with one another unless specifically stated otherwise.

The aspects and embodiments of the present invention are described with reference to the figures, wherein like reference numerals generally refer to like elements. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects of the present invention.

Figure 1a shows a schematic side view of an oxidizable metallic workpiece 100 according to one embodiment and Figure 1b shows a schematic side view of an oxidizable metallic workpiece 100 according to a further embodiment. Figure 1c shows schematically a cross or longitudinal section of an oxidizable metallic workpiece 100 according to a further embodiment.

As shown schematically in Figures 1a, 1b and 1c, the oxidizable metallic workpiece 100 (hereinafter also referred to as workpiece for short) can be a metallic sheet according to one embodiment. Alternatively, the workpiece 100 can be a workpiece 100 of any shape depending on the application scenario. The workpiece can comprise, for example, iron, chromium and/or nickel, in particular as alloying elements and/or in particular be a steel according to one of the DIN standards 1.4301, or 1.4307 or 1.0503 or 1.4404.

As shown in Figure 1a, the oxidizable metallic workpiece 100 has a thermally generated oxide layer 101 on at least one workpiece surface. As shown in Figure 1b, the workpiece 100 can have the oxide layer 101 on both sides, in particular on all outer workpiece surfaces of the workpiece 100. As shown in Figure 1c, the oxide layer 101 of the oxidizable metallic workpiece 100 can be arranged circumferentially on each material surface of the workpiece 100.

The oxide layer 101 can be homogeneously distributed on the at least one workpiece surface. The oxide layer 101 can completely cover the at least one workpiece surface.

As shown only schematically in Figure 1a, the oxide layer 101 is designed to at least partially absorb ultraviolet radiation 103 incident on the oxidizable workpiece, in particular at any angle of incidence a, and to at least reduce reflection of the ultraviolet radiation 105 reflected by the oxide layer 101. The angle of incidence a can be between 0° and 180° (relative to the surface of the oxide layer 101).

The oxide layer 101 has a composition of different metal oxides which are designed to absorb a predetermined light wavelength range of the ultraviolet radiation 103 incident on the oxidizable metallic workpiece 100.

The metal oxides of the oxide layer 101 can include magnetite (Fe3O4) and hematite (Fe2O3). The ratio of magnetite to hematite can be between 10 volume percent magnetite to 90 volume percent hematite to 70 volume percent magnetite to 30 volume percent hematite based on the total volume of the oxide layer 101, in particular between 20 volume percent magnetite to 80 volume percent hematite to 50 volume percent magnetite to 50 volume percent hematite.

The predetermined wavelength of ultraviolet radiation absorbed by the metal oxides can be, for example, between 240 nm and 295 nm, preferably between 250 nm and 285 nm, more preferably between 252 nm and 256 nm.

Alternatively, the predetermined wavelength of ultraviolet radiation absorbed by the metal oxides can be, for example, between 340 nm to 470 nm, preferably 360 nm to 380 nm. The oxide layer 101 can act as an efficient absorption filter for ultraviolet radiation in the wavelength range between 250 nm and 450 nm. The ultraviolet radiation can pass through the oxide layer 101 until it is reflected back, can be reflected once or multiple times within the oxide layer 101 and can pass through the oxide layer 101 once or multiple times again. The ultraviolet radiation can be partially absorbed in the process.

According to the Lambert-Beer law, the absorption of ultraviolet radiation when passing through the oxide layer 101 is wavelength-dependent and proportional to the absorption coefficient of the material being irradiated and the thickness of the layer being irradiated. According to the law of conservation of energy, the absorbed portion of radiation leads to a reduction in reflectivity.

Depending on the nature of the metal oxides and the thickness of the oxide layer 101, different frequency ranges of the ultraviolet radiation can be absorbed or reflected to varying degrees. The oxide layer 101 can appear yellowish to reddish and reflect red light frequencies and absorb blue ones. The absorption can cover the light wavelength ranges between 250 nm or less and 450 nm. In particular, the effect of resonance absorption can come into play.

The incident ultraviolet radiation 103 may be designed to excite the metal oxides of the oxide layer 101 depending on the nature of the metal oxides.

The effective range of the oxide layer 101 can be set to the UV-C range, in particular to 254 nm. The effectiveness of the oxide layer 101 can, as shown in more detail below, include effectiveness over a larger range of light wavelengths. The reflection reduction can cover a light wavelength range of at least 250 nm to 450 nm. As shown below, the oxide layer 101 can be effective in the complete UV-A range, i.e. at a wavelength of 315 nm to 400 nm, in the complete UV-B range, i.e. at a wavelength of 280 nm to 315 nm, and at least from 250 nm to 280 nm of the UV-C range. The oxide layer 101 can thus be used particularly advantageously in disinfection applications in which wavelengths around 254 nm and between 270 nm to 285 nm are typically used. Furthermore, the oxide layer 101 can be used, for example, at a wavelength of 340 nm to 470 nm, in particular from 360 nm to 380 nm, which is suitable for UV curing of adhesives. Figure 2 shows a method 200 for thermally generating the oxide layer 101 of the oxidizable workpiece 100 according to one embodiment.

As shown in Figure 2, the method 200 comprises a step of heating 201 the oxidizable metallic workpiece 100 for a predetermined duration and a predetermined temperature while supplying a predetermined amount of gas with a predetermined oxygen content in order to obtain the oxide layer 101 on a material surface of the oxidizable metallic workpiece 100, which, as already described, is designed to at least partially absorb ultraviolet radiation 103 incident on the oxidizable workpiece and at least to reduce reflection of the ultraviolet radiation 105 reflected by the oxide layer 101. The oxide layer 101 has a composition of different metal oxides, which are designed to absorb a predetermined light wavelength range of the ultraviolet radiation 103 incident on the oxidizable metallic workpiece 100.

Furthermore, the method 200 may comprise, prior to the step of heating 201 the oxidizable metallic workpiece 100, determining the predetermined duration and/or the predetermined temperature; and/or determining the predetermined amount of oxygen.

In this respect, the predetermined duration, the predetermined temperature and/or the predetermined amount of oxygen can be determined for the heating 201, which achieves an advantageous layer thickness and/or composition of the oxide layer 101 of the workpiece 100.

Figure 3 shows a diagram with a heating curve 300 of a temperature during the method 200 for producing the oxide layer 101 of the workpiece 100 according to an embodiment. The time of the temperature treatment method in minutes is shown on the abscissa of Figure 3 and a temperature of the temperature treatment method is shown on the ordinate of Figure 3.

The creation of the oxide layer 101 is described below using a steel sheet made of 1.4301 steel (also called V2A steel), i.e. in accordance with DIN standard 1.4301, in a furnace. Other steels, in particular other FeCr steels, can be used to create the oxide layer 101. The parameters listed below during production, such as temperature, duration and O2 concentration, can vary accordingly.

Other devices for applying temperature to the workpiece 100 may be used, such as inductively based systems or systems based on heated fluids, the latter especially for pipes.

The oxide layer 101 can be created by a temperature treatment similar to tempering. In steel processing, tempering can be used to change the properties of the steel, such as hardness and toughness, and to reduce internal stresses. Here, however, the aim of the temperature treatment is not to influence the internal crystal structure of the material in order to bring about changes in the mechanical material properties, but rather to specifically build up the oxide layer 101.

As shown by the heating curve 300 in Figure 3, the temperature treatment can comprise a heating phase 301, a holding phase 303 and a cooling phase 305. The heating step 201 of the method 200 described in relation to Figure 2 can comprise the holding phase 303 and in particular at least portions of the heating phase 301 and/or the cooling phase 305.

In the heating phase 301, the temperature can be continuously increased to a temperature value between 380°C and 410°C, in particular 400°C, for the temperature treatment of the, in particular uncoated, workpiece 100. The heating phase 301 can last, for example, 45 minutes.

In the holding phase 303, the temperature can be kept at the temperature value. The holding phase 303 can last for 150 minutes, for example. During the holding phase 303, a shape and size of metal oxide crystals in the oxide layer 101 can be advantageously formed and the oxide layer 101 can also achieve an advantageous layer thickness.

In the cooling phase 305, the temperature can be continuously reduced starting from the temperature value. The cooling phase 305 can last, for example, 45 minutes.

As shown in Figure 3, a temperature range 307 at which a favorable oxide layer 101 is formed may be the temperature value during the holding phase 303 The temperature range 307 can include a value range between 380°C and 410°C. If the temperature falls below the temperature range 307 during the holding phase 303, the oxide layer 101 can become too thin and/or an unfavorable composition of the oxides can arise, whereby the reflectivity of the oxide layer 101 in the UV range can be too high. If the temperature range 307 is exceeded, material-related intergranular corrosion can occur in the material of the steel sheet 301.

For an advantageous conversion of the boundary layer or the individual crystals of the metal oxides on the surface of the steel, oxidation is provided. In the temperature treatment process, it can be provided to supply ambient air during the tempering process, i.e. mainly during the holding phase 303, but in particular also in the transition phases between the holding phase 303 and the heating phase 301 and/or the cooling phase 305.

In this way, enough oxygen can be added to the process so that the crystals of the metal oxides can be advantageously formed and the boundary layer can be advantageously converted. If gas with too high an oxygen concentration is added, an undesirable combustion-promoting atmosphere can develop in the furnace, so ambient air with the typical oxygen content of around 21% can be very suitable.

The resulting oxide layer 101 can be yellow, golden yellow, yellow-brown or brown-red. This is caused by oxygen diffusing into the upper metal layers of the steel when heated. The color depends on how deeply the oxygen penetrates into the surface layer. The penetration depth in turn depends on the temperature and the duration of exposure. The color can also depend on the thickness of the oxide layer 101.

Figure 4 shows a diagram with measurement results of a reflectivity of the workpiece 100 according to an embodiment as a function of a residual radiation intensity. The abscissa of Figure 4 shows the residual radiation intensity of the workpiece 100 in mW/cm ² and the ordinate of Figure 4 shows the reflectivity of the workpiece 100 in percent.

The measurements in Figure 4 show the reflection-reducing effect of the oxide layer 101. Here, the workpiece 100 was placed in an Ulbricht sphere and irradiated with UV-C radiation with a wavelength of 254 nm. The reflected radiation was measured by a UV-C Sensor and the residual radiation intensity is measured. The measured value 405 of the workpiece 100 can be converted to the reflectivity of the workpiece 100 by interpolation of reference samples with first and second reference reflection values 401, 403 of first and second reference samples.

The first reference sample is a white sheet of metal. The first reference reflection value 401 is 93.53% at a sensor irradiation of 0.5420 mW/cm ² .

Furthermore, the second reference sample is designed as a standard black sheet. The second reference reflection value 403 is 2.03% at a sensor irradiation of 0.0173 mW/cm ² .

Thus, the measured reflectivity of the workpiece 100 is 9.3%. With a calculated maximum measurement inaccuracy of 5%, the actual reflectivity of the workpiece 100 can be proven to be 9.8%.

This measurement value could be remeasured and proven several times.

Since an uncoated 1.4301 BLANK steel sheet has a reflection value of more than 30%, the coated steel sheet achieves a reduction in reflectivity of more than 67%. The oxide layer 101 of the workpiece 100 therefore has advantageous reflection-reducing properties in the UV range that typical metallic surfaces do not have.

Figure 5a shows a diagram with measurement results of a reflectivity of the workpiece 100 according to an embodiment as a function of a wavelength of radiation applied to the workpiece 100. The wavelength of the radiation in nanometers is shown on the abscissa of Figure 5a and the reflectivity of the workpiece 100 in percent is shown on the ordinate of Figure 5a.

Curve 501 shows the measured values on workpiece 100. The measurements were carried out at an ISO 9001 certified institute using a calibrated (calibration standard certificate, Physikalisch-Technische Bundesanstalt: PTB 44052/15) Perkin-Elmer Lambda 950 UV-VIS-NIR spectrometer (serial number 950L1211082). A second curve 503 shows an uncoated reference sheet made of steel according to DIN standard 1.4301 in comparison with a reflectivity of more than 30% over the wavelength range from 250nm to 400nm, in particular 33.76% at 254nm.

As shown in Figure 5a, a ratio of an intensity of the ultraviolet radiation 105 reflected by the oxide layer 101 to an intensity of the ultraviolet radiation 103 incident on the oxide layer 101, in particular in a light wavelength range of 250 nm to 280 nm and/or 280 nm to 330 nm, can be less than 15%, in particular less than 10%. In particular, a ratio of the intensity of the ultraviolet radiation 105 reflected by the oxide layer 101 to an intensity of the ultraviolet radiation 103 incident on the oxide layer 101, i.e. a reflectivity, can be 9.44% at a light wavelength of 254 nm.

As further shown in Figure 5a, a ratio of an intensity of the ultraviolet radiation 105 reflected by the oxide layer 101 to an intensity of the ultraviolet radiation 103 incident on the oxide layer 101, in particular in a light wavelength range from 330 nm to 400 nm, can be below 20%, in particular below 17.5%.

In particular, at the wavelength of 254 nm, a reduction in reflectivity of more than 67% can be achieved by the coated steel sheet. The reduction in reflectivity can be calculated based on the quotient of the corresponding reflectivities at the wavelength of 243 nm as follows: 1-9.44/33.76=72%. The oxide layer 101 of the workpiece 100 therefore has advantageous reflection-reducing properties in the UV range that typical metallic surfaces do not have.

Figure 5b shows a diagram with measurement results of a reflectivity of the workpiece 100 according to an embodiment as a function of a wavelength of the radiation applied to the workpiece 100. The wavelength of the radiation in nanometers is shown on the abscissa of Figure 5b and the reflectivity of the workpiece 100 in percent is shown on the ordinate of Figure 5b.

Here, a fourth curve 505 shows the measured values at the first measuring point of the workpiece 100 and curve 507 shows measured values of the uncoated reference sheet made of steel according to DIN standard 1.4301 in comparison (%R > 30%). As shown in Figure 5b, a ratio of an intensity of a further radiation reflected by the oxide layer 101 to an intensity of the further radiation incident on the oxide layer 101 in a visible wavelength range from 450 nm to 600 nm can be over 15%, in particular over 20%, and from 600 nm to 800 nm over 35%, in particular over 40%.

Figure 6a shows a side view of a radiation filter 600 in cross section with the workpiece 100 according to an embodiment and a further workpiece 100' according to an embodiment. The further workpiece 100' can have one or more features of the workpiece 100. The further workpiece 100' comprises a further oxide layer 101'. The further oxide layer 101' can have one or more features of the oxide layer 101.

The radiation filter 600 can be designed to reduce the intensity of ultraviolet radiation. The longitudinal direction 601-1 of the radiation filter 600, the transverse direction 601-2 of the radiation filter 600, and the vertical direction 601-3 of the radiation filter 600 are shown schematically in Figure 6a.

As shown in Figure 6a, the workpiece 100 and the further workpiece 100' can be manufactured in a wave-shaped manner. The workpiece 100 and the further workpiece 100' can be spaced apart from one another. The respective oxide layers 101, 101' of the workpieces 100, 100' can face one another.

As shown in Figure 6a, the workpiece 100 and the further workpiece 100' can be shaped in a wave-like manner with wave fronts arranged one behind the other in the longitudinal direction 601-1. A fluid channel can be formed between the workpiece 100 and the further workpiece 100' in the propagation direction, i.e. in the longitudinal direction 601-1, of the wave fronts. As a result, the incident ultraviolet radiation 103, which enters the radiation filter 600, for example in the longitudinal direction 601-1 or at an angle to the longitudinal direction 601-1, can be reflected multiple times between the first workpiece 100 and the further workpiece 100' and thus the intensity of the multiple reflected ultraviolet radiation 105 can be reduced.

Figure 6b shows another view of a radiation filter 600 with a plurality of

Workpieces 100 according to an embodiment. As shown in Figure 6b, the A plurality of workpieces 100 can be arranged one above the other in engagement in the vertical direction 601-3 and form a stack.

The plurality of workpieces 100 can be arranged in a contactless manner to form a fluid channel between the workpieces 100.

For a stable arrangement of the workpieces 100, for example as shown in Figure 6b to form the stack, the workpieces 100 can be connected by means of at least one connecting web 603 extending in the longitudinal direction 601-1 and the vertical direction 601-3.

In one embodiment, the web can be made from the workpiece 100 and have a layer according to 101.

The at least one connecting web 603 can extend in the vertical direction 601-3 and pass through the respective workpieces 100, for example through a slot formed in the respective workpieces 100 in the longitudinal direction 601-1.

In one embodiment, the workpieces 100 are spaced apart from one another and guided via lateral guide slots 605 formed in the longitudinal direction 601-1, in particular in a wave-shaped manner. The lateral guide slots 605 are shown in Figure 6c.

Figure 7 shows a view of a radiation filter 600 in an irradiation arrangement 700 according to an embodiment.

The irradiation arrangement 700 is designed to irradiate a flowing fluid with ultraviolet radiation and comprises a housing 701 with a housing interior 703. The housing 701 is designed to guide the flowing fluid in the housing interior 703 along a flow direction 705 shown only schematically in Figure 7. The housing 701 has a fluid inlet side 707 which is designed to receive the fluid and a fluid outlet side 709 which is designed to discharge the flowing fluid. The flowing fluid is guided from the fluid inlet side 707 to the fluid outlet side 709 through the housing 701. The irradiation arrangement 700 further comprises a lighting means 711, which can be arranged in the housing interior 703 between the fluid inlet side 707 and the fluid outlet side 709 along the flow direction 705 in the longitudinal direction 601-1, and is designed to irradiate the fluid guided through the housing 701 with ultraviolet radiation.

The irradiation arrangement 700 further comprises the radiation filter 600 described in the previous embodiments for Figures 6a or 6b, which is arranged on the fluid inlet side or fluid outlet side and is designed to reduce the intensity of ultraviolet radiation emerging on the fluid inlet side or fluid outlet side. The radiation filter 600 further comprises the oxidizable metallic workpiece 100 comprising the oxide layer 101.

In Figure 7, the radiation filter 600 is shown on the fluid inlet side and a further radiation filter 600' on the fluid outlet side. The further radiation filter 600' can have one or more of the features of the radiation filter 600 described in Figures 6a and 6b. The workpiece 600 of the radiation filter 600 can be designed according to one of the embodiments of Figures 1a to 1c.

The fluid inlet side 707 can have a fluid inlet 713, wherein the radiation filter 600 is arranged downstream of the fluid inlet 713 in terms of fluid flow, i.e. is arranged at a distance from the fluid inlet side in the longitudinal direction 601-1. The fluid outlet side 709 can have a fluid outlet 715, wherein the further radiation filter 600' is arranged upstream of the fluid outlet 715 in terms of fluid flow, i.e. is arranged at a distance from the fluid outlet side in the longitudinal direction 601-1.

The radiation filter 600 can be designed to guide the fluid in the flow direction 705, in particular to form a fluid channel in the flow direction 705. In one embodiment, the fluid channel formed by the radiation filter 600 or by the radiation filter 600 and the further radiation filter 600' is formed laminarly in the longitudinal direction 601-1 along the lighting means 711 between the fluid inlet 713 and the fluid outlet 715.

As shown in Figure 7, the radiation filter 600 and the workpiece 100 with the oxide layer 101 can be designed to guide the fluid flowing through the housing interior 703 in the fluid channel in a laminar manner in order to provide the radiation filter 600 with to generate downstream laminar fluid flow in the longitudinal direction 601-1.

In one embodiment, the housing shape of the irradiation arrangement 700 at least partially follows the structural arrangements of the radiation filter 600 in order to ensure efficient use of the fluid channel, even if this is not shown in Figure 7.

The fluid outlet side 709 can have(s) a fan(s) 717 or a pump(s) 717, which is designed to generate negative pressure in the housing interior 703 in order to guide the fluid along the flow direction 705 through the radiation filter 600 or through the radiation filter 600 and the further radiation filter 600'.

The use of the workpiece 100 allows a particularly efficient irradiation arrangement 700. Efficiency has been proven by a VDE certification under the certificate number 40056875. The certificate guarantees compliance with electrical safety (Safety Standard, EN ISO 62471, Photobiological Safety - Risk Class 0) and proves requirements according to DIN TS 67506 (disinfection classification class 100 >= 400 joules) and VDI 4300 Sheet 14.

The use of the irradiation arrangement 700 with the radiation filter 600 and the workpiece 100 with 101 is particularly relevant when irradiating the fluid with ultraviolet radiation to inactivate or damage microorganisms, such as bacteria or viruses. A corresponding inactivation or damage to the microorganisms is achieved in particular by damaging the DNA of the microorganisms by irradiating the microorganisms with ultraviolet (UV) light, so that the reproduction of the microorganisms is inhibited and thus inactivated.

A large number of microorganisms are transmitted through the air, e.g. through aerosols present in the air to which the microorganisms attach. If the aerosols containing the attached microorganisms are inhaled by a living being, the microorganisms can infect the living being.

Aerosols can thus serve as carriers of microorganisms in the fluid, for example in air, and can float in the fluid for a long time and, for example, in enclosed spaces. An infection of a living being can occur, for example, through microorganisms when microorganisms attached to aerosols reach the mucous membranes of the nose, mouth and/or eyes of the living being and then multiply in the living being.

However, microorganisms adhering to aerosols are more susceptible to damage than when these microorganisms are suspended in a liquid, so that damage to the DNA of the microorganisms adhering to aerosols by ultraviolet radiation is particularly effective, and effective air disinfection is achieved.

Particularly in sensitive areas such as hospitals, air disinfection in treatment rooms and inpatient facilities plays a major role in preventing people from becoming infected with microorganisms. But disinfection of the room air is also beneficial in other rooms, such as classrooms, where a large number of people spend a long time, especially if the rooms in question are only ventilated irregularly. However, the ultraviolet radiation used to irradiate the microorganisms must not enter a room used by people, or only in very reduced amounts. This can be achieved particularly efficiently using the oxide layer 101 of the workpiece 100 described above and below, and its integration into the radiation filter 600.

Even though the use of the workpiece 100 has been described in detail for a radiation filter 600 of an irradiation arrangement 700, the workpiece 100 is not limited to this advantageous application.

Applications of the workpiece 100 can be, for example, material protection and/or personal protection to protect against artificial and/or natural UV radiation, in particular UV-C radiation.

The shape of the workpiece 100 may depend on the application and can be adapted to the application. Arrangements of the workpieces 100, 100' and their oxide layers 101, 101' other than those shown in the previous figures can be used, in particular to achieve multiple reflections. For example, in space telescopes, elements and/or people positioned behind the workpiece 100 can be protected from UV radiation, in particular UV-C radiation. This makes it possible, for example, to use materials positioned behind the workpiece 100 that have not yet been able to be installed due to their susceptibility to UV radiation or that may not be economically viable. New materials can also be used, for example, in satellites and/or manned or unmanned spacecraft, space capsules, space shuttles or space stations if they are protected from UV radiation by the workpiece 100.

For example, elements and persons can be protected from ultraviolet radiation during curing processes with UV radiation, especially during 3D printing or the (industrial) curing of UV reactive adhesives.

For example, devices, organisms and/or people in areas affected by ozone holes with increased UV radiation exposure on the earth's surface can be effectively protected from UV radiation by the workpiece 100 and, in particular, exposure to natural light can be ensured. The workpiece 100 can be used, for example, as a UV, in particular UV-C, filter.

For example, components, persons and/or organisms located behind the workpiece 100 can be protected from UV radiation, in particular from artificial UV-C radiation, in terrestrial applications. Examples of terrestrial applications are water disinfection, air disinfection, surface disinfection and laboratory protection.

The workpiece 100 and the radiation filter 600 can be exposed to UV-C irradiation for a long time.

The workpiece 100 with the oxide layer 101 and the radiation filter 600 were tested according to DIN EN ISO 3651-2 and DIN EN ISO 9227 for risk-free corrosion and intergranular corrosion. The workpiece 100 can also be manufactured efficiently and cost-effectively, can be designed free of additives, can be used on large-area, complex-shaped, undercut parts and can be used on hard-to-reach and/or small-dimensioned component regions such as gaps and slots, and can be manufactured industrially and automatically. List of reference symbols:

100 Oxidizable metallic workpiece

100‘ Additional oxidizable metallic workpiece

101 Oxide layer of the oxidizable metallic workpiece

101 ‘ Oxide layer of the further oxidizable metallic workpiece

103 Incident ultraviolet radiation

105 Reflected ultraviolet radiation

200 Processes for the thermal generation of the oxide layer

201 procedural step of the procedure

300 heating curve

301 heating phase

303 holding phase

305 cooling phase

401 First reference reflection value

403 Second reference reflection value

405 Reflection measurement value of the workpiece

501 First curve: Reflection values of the workpiece over the wavelength

503 Second curve: Reflectance values of 1.4301 -Blank over the wavelength

505 Third curve: Reflection values of the workpiece over the wavelength

507 Fourth curve: Reflectance values of 1.4301 -Blank over the wavelength

600 radiation filters

600’ Additional radiation filter

601-1 Longitudinal direction of the radiation filter

601-2 Transverse direction of the radiation filter

601-3 Vertical direction of the radiation filter

603 connecting bridge

605 guide slots

700 irradiation arrangement

701 housing

703 housing interior

705 flow direction

707 fluid inlet side

709 fluid outlet side

711 bulbs

713 fluid inlet 715 fluid outlet

717 Fan/Pump

Claims

PATENT CLAIMS 1. Oxidizable metallic workpiece (100), wherein the oxidizable metallic workpiece (100) has a thermally generated oxide layer (101) on at least one workpiece surface, wherein the oxide layer (101) is designed to at least partially absorb ultraviolet radiation (103) incident on the oxidizable workpiece and to at least reduce reflection of the ultraviolet radiation (105) reflected by the oxide layer (101), wherein the oxide layer (101) has a composition of different metal oxides which are designed to absorb a predetermined light wavelength range of the ultraviolet radiation (103) incident on the oxidizable metallic workpiece (100). 2. Oxidizable metallic workpiece (100) according to claim 1, wherein the oxidizable metallic workpiece (100) comprises iron, chromium and/or nickel, in particular steel according to one of the DIN standards 1.4301 or 1.4307 or 1.0503 or 1.4404. 3. Oxidizable metallic workpiece (100) according to claim 1 or 2, wherein the metal oxides of the oxide layer (101) comprise magnetite (FeO) and hematite (Fe2O3). 4. Oxidizable metallic workpiece (100) according to claim 3, wherein the ratio of magnetite to hematite is between 10 volume percent magnetite to 90 volume percent hematite to 70 volume percent magnetite to 30 volume percent hematite based on the total volume of the oxide layer (101), in particular between 20 volume percent magnetite to 80 volume percent hematite to 50 volume percent magnetite to 50 volume percent hematite. 5. Oxidizable metallic workpiece (100) according to one of the preceding claims, wherein the oxide layer (101) is designed to reflect a radiation component in a wavelength range from 560 nm to 650 nm. 6. Oxidizable metallic workpiece (100) according to one of the preceding claims, wherein the predetermined light wavelength of the ultraviolet radiation absorbed by the metal oxides is between 240 nm and 295 nm, preferably between 250 nm and 285 nm, more preferably between 252 nm and 256 nm. 7. Oxidizable metallic workpiece (100) according to one of claims 1 to 5, wherein the predetermined light wavelength of the ultraviolet radiation absorbed by the metal oxides is between 340 nm and 470 nm, preferably between 360 nm and 380 nm. 8. Oxidizable metallic workpiece (100) according to one of the preceding claims, wherein a ratio of an intensity of the ultraviolet radiation (105) reflected by the oxide layer (101) to an intensity of the ultraviolet radiation (103) incident on the oxide layer (101), in particular in a light wavelength range of 250 nm to 280 nm and/or 280 nm to 330 nm, is less than 15%, in particular less than 10%, and/or wherein the ratio of the intensity of the ultraviolet radiation (105) reflected by the oxide layer (101) to the intensity of the ultraviolet radiation (103) incident on the oxide layer (101), in particular in a light wavelength range of 330 nm to 450 nm, is less than 20%, in particular less than 17.5%. 9. Oxidizable metallic workpiece (100) according to one of the preceding claims, wherein the oxidizable metallic workpiece (100) is designed as a plate, in particular wherein the oxidizable metallic workpiece (100) designed as a plate is wave-shaped, in particular waves of the wave-shaped oxidizable metallic workpiece (100) extend at least along an extension direction of the oxidizable metallic workpiece (100). 10. Oxidizable metallic workpiece (100) according to one of the preceding claims, wherein a shape of the oxidizable metallic workpiece (100) is at least partially formed by one of the following manufacturing processes: machining processes, in particular milling, turning, drilling, countersinking, grinding, planing, punching, reaming, sawing, filing, rasping, brushing, grinding, jet cutting, honing or primary forming processes, in particular casting, sintering, 3D printing, laser sintering, or forming processes, in particular bending, extrusion, upsetting, embossing, countersinking, Punching, deep drawing, collar drawing, cold forming, cold rolling, warm and hot forming, warm and hot rolling, punching, forging, or joining processes, in particular assembling, pressing and pressing in, primary shaping, forming, fusion welding, pressure welding, soldering, gluing. 11. Oxidizable metallic workpiece (100) according to one of the preceding claims, wherein the oxide layer (101) is resistant to ultraviolet radiation. 12. Oxidizable metallic workpiece (100) according to one of the preceding claims, wherein the oxidizable metallic workpiece (100) is resistant to corrosion and/or intergranular corrosion, in particular according to the DIN standards DIN EN ISO 3651-2 and/or DIN EN ISO 9227. 13. Method (200) for thermally producing the oxide layer (101) of the oxidizable workpiece (100) according to one of claims 1 to 12, wherein the method (200) comprises: Heating (201) the oxidizable metallic workpiece (100) for a predetermined duration and a predetermined temperature while supplying a predetermined amount of gas with a predetermined oxygen content in order to obtain an oxide layer (101) on a material surface of the oxidizable metallic workpiece (100), which oxide layer is designed to at least partially absorb ultraviolet radiation (103) incident on the oxidizable workpiece (100), and to at least reduce reflection of the ultraviolet radiation (105) reflected by the oxide layer (101), wherein the oxide layer (101) has a composition of different metal oxides which are designed to absorb a predetermined light wavelength range of the ultraviolet radiation incident on the oxidizable metallic workpiece (100). 14. Irradiation arrangement (700) for irradiating a fluid with ultraviolet radiation, comprising: a housing (701) with a housing interior (703), wherein the housing (701) is designed to guide the fluid in the housing interior (703) along a flow direction (705), wherein the housing (701) has a fluid inlet side (707) which is designed to receive the fluid, and a fluid outlet side (709) which is designed to dispense the fluid, wherein the fluid is guided from the fluid inlet side (707) to the fluid outlet side (709) through the housing (701); a lighting means (711) which is arranged in the housing interior (703) between the fluid inlet side (707) and the fluid outlet side (709) and is designed to irradiate the fluid guided through the housing (701) with ultraviolet radiation; and a radiation filter (600) which is arranged on the fluid inlet side or fluid outlet side on or in the housing (701) and is designed to reduce the intensity of ultraviolet radiation emerging on the fluid inlet side or fluid outlet side; wherein the radiation filter (600) comprises an oxidizable metallic workpiece (100) according to one of claims 1 to 13. 15. Irradiation arrangement (700) according to claim 14, wherein the radiation filter (600) further comprises a further oxidizable metallic workpiece (100') according to one of claims 1 to 13, wherein the oxidizable metallic workpiece (100) and the further oxidizable metallic workpiece (100') are spaced apart from one another, wherein in particular the respective oxide layers (101, 101') of the oxidizable metallic workpieces (100, 100') face one another and/or wherein in particular the oxidizable metallic workpieces (100, 100') are wave-shaped.