Device for ionizing an air stream and method for manufacturing such a device for ionizing an air stream

Abstract

A device (1) for ionizing an air stream comprises a container (2) made of electrically insulating material, an inner electrode (3) arranged inside the container (2), an outer electrode (10) arranged on the outside of the container (2), and control electronics (12) connected to the inner electrode (3) and the outer electrode (10) for supplying a voltage. The inner and / or outer surface of the container (2) is acid-treated. An electrically conductive material (7) is placed inside the container (2) with the inner electrode (3) inserted into the electrically conductive material (7), and the inner electrode (3) is surrounded by the electrically conductive material (7). The inner and / or outer surface of the container (2) is made hydrophobic by silanization.

Description

[0001] The invention relates to a device for ionizing an air stream with a container made of electrically insulating material, an inner electrode arranged in the interior of the container and an outer electrode arranged on the outside of the container, and with control electronics which are connected to the inner electrode and the outer electrode for application of a supply voltage, wherein the inner and / or outer surface of the container is acid-treated and an electrically conductive material is pressed together with the inner electrode inserted into the electrically conductive material in the interior of the container and the inner electrode is surrounded by the electrically conductive material.

[0002] The invention further relates to a method for manufacturing such a device for ionizing an air stream.

[0003] The device is specifically designed and suitable for generating hydroxyl radicals -OH and ozone O3.

[0004] EP 3 120 185 B1 discloses an ionization device comprising a glass bulb, an inner electrode arranged inside the glass bulb, and an outer electrode arranged on the outer side of the glass bulb. The glass bulb is covered with a polymer film. This ensures that glass fragments are contained and no hazard arises.

[0005] GB 2 093 638 A discloses an ion generator with a concentric inner electrode and an outer electrode surrounding it in a cylindrical shape, wherein an activated carbon fabric is arranged in the space between the inner electrode and the outer electrode.

[0006] EP 0 789 666 B1 also discloses a device for generating ozone in which the gap between two electrodes is filled by an electrically conductive and thermally conductive, gas-permeable arrangement made of wire as a braid, woven fabric or knitted fabric.

[0007] US 2008 / 0030918 A1 describes an ionizer with discharge needles and a wire grid to which a voltage is applied.

[0008] US 2003 / 0137794 A1 discloses an ion generator with a glass tube. The electrode configuration proposes a ground electrode made of a stainless steel wire mesh and a working electrode made of a stainless steel plate.

[0009] EP 0 231 436 A1 describes a spray electrode which has aluminium granules as the filling of a tube made of quartz or a comparable insulating material which is closed at the spraying end.

[0010] US 2004 / 0256225 A1 describes a device for dielectrically hindered discharge with a glass tube filled with coarse-grained carbon granules with a grain size of 3 to 5 mm x 1 mm.

[0011] WO 97 / 09268 A1 discloses a device for generating ozone comprising a rod-shaped inner electrode, a cylindrical outer electrode, and an intermediate cylindrical dielectric. The gap between the inner electrode and the dielectric, and the gap between the outer electrode and the dielectric, are filled by an electrically conductive, thermally conductive, and gas-permeable arrangement. A gas stream is passed through the gaps of the tubular device, and ozone is generated by dielectrically hindered discharge at the dielectric. The gas-permeable arrangement in the gaps can be chips, granules, wire, mesh, fabric, nonwoven, knitted, or porous granules, provided that gas permeability is ensured such that the gap volume is not filled by more than 50%.

[0012] US 2017 / 333587 A1 discloses an ozone generator consisting of a glass tube, an inner electrode made of rolled perforated aluminum sheet, and an outer electrode made of a tubular stainless steel wire mesh.

[0013] DE 10 2005 056 726 A1 shows a device for ozone production by means of dielectrically hindered discharge with a carrier body made of soda-lime glass, into which a stainless steel wool is inserted as an internal electrode, which is intended to be crucial for low energy consumption.

[0014] A generic device for ionizing ambient air with the features of the preamble of claim 1 of the present invention is disclosed in EP 4 175 082 B1.

[0015] Based on this, the object of the present invention is to create a further improved device for the ionization of ambient air, which leads to an even higher yield of radicals, in particular hydroxyl radicals, and effective ozone while reducing harmful nitrogen compounds (NO₂). X leads.

[0016] The problem is solved by the device with the feature of claim 1. Advantageous embodiments are described in the dependent claims.

[0017] It is proposed that the inner and / or outer surface of the container, roughened by acid treatment, is made hydrophobic by silanization.

[0018] The surface of the container is roughened by the acid treatment and further made hydrophobic by silanization. This increases the surface resistance and the charge density on the container's surface. As a result, the plasma reaction occurring at the Helmholtz layer is intensified, so that, without changing the potential difference of the plasma reaction, the yield—especially of the disinfectant hydroxyl radicals—is significantly increased compared to the standard device.

[0019] The electrically conductive material surrounding the inner electrode and placed inside the container can be a wire mesh, electrically conductive granules, a solid electrically conductive material, or similar. The granules can be pressed into a solid material or compressed after being placed inside the container.

[0020] Such granules preferably have a mean particle size of up to 450 µm and preferably a particle size distribution in the range of 10 to 450 µm. These granules are arranged in the interior of the container, with the granules being compressed when the inner electrode is inserted and the inner electrode being surrounded by the granules.

[0021] In contrast to filling the container with electrically conductive solid material, a wire mesh, or simply air, fine-grained compressed granules lead to an improved efficiency.

[0022] The air gaps that contribute to the formation of corona discharges in a wire mesh are not present. However, they are also not completely removed, as they are in solid material. The very short, extremely small spaces always present in fine-grained granules, especially fine-grained powders, result in a higher ionization efficiency compared to solid material. Similarly, compared to fiber materials and fabrics used as intermediate materials with larger air inclusions, a granule filling with electrically conductive particles also leads to a higher degree of ionization.

[0023] In particular, in combination with the surface of the container roughened by etching and made hydrophobic by silanization, a fine-grained coal powder, i.e., coal dust, has proven to be particularly advantageous.

[0024] The electrically conductive material can consist of granules containing, for example, aluminum, copper, stainless steel, titanium, graphite, and / or magnesium particles. These can also be present in the form of alloys, such as bronze, brass, and the like.

[0025] Furthermore, precious metals can be used in a similar form as electrode materials, such as gold, platinum, palladium, silver, etc.

[0026] It is also conceivable to electroplat the surface of the metal materials used for the granules and / or the electrodes. For example, copper or copper shot can be coated with gold.

[0027] Such granules are particularly suitable with a medium grain size in the range of 10 to 450 µm.

[0028] The electrically conductive material can be compressed after the inner electrode is inserted. This further improves the ionization properties. A compression weight of 2 to 3 kg, preferably about 2.35 kg, is suitable for this purpose. Compression can be performed before the granules and inner electrode are placed in the container, so that the compressed granules, such as a volume of graphite, are introduced into the container as a solid material. Alternatively, compression can also be performed inside the container after the inner electrode and the granules surrounding it have been inserted.

[0029] The electrically insulating container can, for example, be made of a dielectric material. A container made of glass or ceramic is particularly suitable. Glass with a dielectric constant of 2 to 16, and preferably in the range of 6 to 9, is especially suitable. For example, a glass material with a dielectric constant of 7.2 and a dielectric loss factor of 70 x 10⁻⁶ has proven suitable. -4 Measured at one megahertz and 25 °C, suitable glass tubes were found to be suitable. Flat-bottomed test tubes made of AR clear glass with a smoothly fused rim are recommended, such as type 231 test tubes made of soda-lime glass or borosilicate glass. The wall thickness is preferably in the range of 0.4 to 1.2 mm.

[0030] It is advantageous if the container has a wall thickness in the range of 0.4 to 1.0 mm. Wall thicknesses in the range of 0.4 to 0.5 mm are suitable, but also those in the range of 0.6 to 0.8 mm. For example, a suitable glass container has a length of 30 mm ± 0.5 mm, an outer diameter of 11.5 mm ± 0.14 mm, and a wall thickness of 0.7 mm ± 0.2 mm.

[0031] In any case, it is advantageous to degrease the surfaces of the container to prevent leakage currents.

[0032] The outer electrode can be a grid structure attached to the outer circumference of the container. A grid size in the range of mesh 20 to mesh 38, and preferably mesh 30, is advantageous for this purpose; that is, the screen size is preferably in the range of 0.465 mm (mesh 38) to 0.85 mm (mesh 20) and particularly preferably in the range of 0.60 mm (mesh 30).

[0033] The choice of mesh size also influences the ionization efficiency and should be neither too small nor too large. A suitable mesh structure (Mesh 30), for example, is made of stainless steel material no. 1.4301 with an inner diameter of 11.3 mm, a mesh size of 0.6 mm, a wire thickness of 0.25 mm, and a length of 25 mm.

[0034] The effective length of the container is preferably in the range of 25 to 35 mm and is preferably 30 mm.

[0035] With optimal device design, the ionization efficiency can be improved through optimized proportions. For example, an outer diameter of 11.5 mm ±0.2 mm, a wall thickness of 0.7 mm ±0.2 mm, and a length of 30 mm ±0.5 mm for the container have proven advantageous. The external electrode then surrounds the container in the area of ​​the granule filling with an effective length of approximately 25 cm.

[0036] However, the design of the device can be enlarged or reduced independently of this, while maintaining the so-called proportions between outer diameter, wall thickness and length.

[0037] The granules can be covered with a silicone seal. For this purpose, a seal made of UKTAsil 60T material with an outer diameter of 10.5 mm and a material thickness of 1 mm, and a hole in the center for the electrode lead, is suitable. Alternatively, liquid silicone can be poured in, compacted, and allowed to cure.

[0038] This electrical insulation prevents contamination, for example, from moisture or additional potting compound. The stripped end of the electrode lead forming the inner electrode can be passed through the silicone cover, with the silicone sheath of the electrode lead abutting the silicone cover. After filling the container with granules, the electrode lead of the inner electrode, with its stripped end attached to the silicone cover, can be inserted into the container. The electrically conductive material, such as the granules, is then compressed by the silicone sheath of the electrode lead and the adjacent silicone cover. This can be achieved with a suitable handling device applying a predetermined pressure.

[0039] The space between the container and the inner wall of the container in the section of the container opening outwards from the silicone cover can then be filled with potting material, such as a resin material.

[0040] The stripped end of the insulating electrode lead can be tinned and aligned centrally within the interior of the container. This stripped end then forms the inner electrode of the device.

[0041] It is also conceivable that the stripped end of a stranded conductor is inserted into the granules in such a way that the individual strands are independently contained within the granules and distributed throughout the container. Thus, the strands of the stripped end of the electrode conductor can be spatially spaced apart from one another within the container, separated by electrically conductive material, such as the granule filling.

[0042] Suitable examples include high-voltage license conductors with silicone insulation and a conductor cross-section of 1 mm². 2 (AWG 15 to 20, preferably AWG 17, i.e. 19 strands of 0.25 mm each) 2 ).

[0043] The invention is explained in more detail below with reference to the accompanying drawings, using an exemplary embodiment. The drawings show: Fig. 1 - Sketch of a device for ionizing an air stream; Fig. 2 - Flowchart for the surface treatment of the container in Fig. 1 device shown; Fig. 3 - Sketch of the device without external electrode; Fig. 4 - Sketch of a disinfection device with aerosol additive.

[0044] Fig. Figure 1 shows a sketch of a device 1 for ionizing an air stream. The device 1 has a container 2 made of an electrically insulating material, preferably a dielectric glass. An internal electrode 3 is arranged in the interior of the container 2. This electrode 3 is, for example, the stripped end of an electrode lead 4, which is surrounded by an insulating sheath 5. Silicone material is suitable as the insulating sheath 5; thus, an electrode lead with silicone insulation can be used, which has a high-voltage withstand rating of at least 10 kV and preferably 20 kV or more. The air stream to be ionized is guided past the outer wall of the container 2.

[0045] The container 2 is closed at the top by a base 6 and open at the opposite end. The stripped end 3 of the electrode lead 4 is inserted from the open end of the container 2 towards the base 6 and is preferably centered with standard tolerances.

[0046] An electrically conductive material 7 in the form of granules is arranged in the interior of the container between the inner wall and the inner electrode 3. Towards the free end of the container 2, the filling of electrically conductive material 7 is then covered with a silicone disc 8. It can be seen that the stripped end 3 of the electrode lead is also partially insulated and passes through the silicone disc 8. To prevent leakage currents and flashover, it is advantageous if a portion of the insulation sheath 5, which may be tapered in diameter, also passes through the silicone disc 8 and extends a few millimeters from there into the electrically conductive material 7.

[0047] The remaining space between the opening in the inner wall of container 2 and the insulating sheath 5 of the electrode lead 4 can then be filled with an electrically insulating filler material 9, such as a resin. This securely holds the electrode lead, together with the silicone disc 8 and the granules 7, within the container 2. The filler material 9, in conjunction with the silicone disc 8, effectively prevents the ingress of contaminants, such as moisture, into the electrically conductive material 7.

[0048] An external electrode 10 is arranged on the outer circumference of the container 2. This electrode can also be made of a grid material that concentrically surrounds the container 2 and, viewed from its outlet towards the end of the container 2 and its base 6, has a length that extends over a substantial part of the length of the filling with the electrically conductive material 7. The length of the external electrode should be approximately two-thirds of the length of the filling with the electrically conductive material 7, i.e., the effective length of the device 1.

[0049] It can be seen that the outer electrode 10 in the illustrated embodiment is designed as a grid structure. The grid size should be in the range of mesh 20 to mesh 38 and preferably mesh 30. This corresponds to a sieve size in the range of 0.85 to 0.456 mm, preferably 0.60 mm.

[0050] Fig. Figure 2 shows a flowchart of the process for manufacturing the device described above. The surface of container 2 is roughened by acid treatment and made hydrophobic by silanization. This increases the surface resistance and the charge density on the surface of container 2. This intensifies the plasma reaction occurring at the Helmholtz layer, thus increasing the yield—especially of the disinfectant hydroxyl radicals—without changing the potential difference of the plasma reaction.

[0051] The procedure has the following steps: a) Rinsing the container (2) with an acetone-containing solution and with water; b) Acid treatment of container 2 by immersing container 2 in an aqueous etching solution, whereby the etching solution is moved at least temporarily relative to container 2; c) Removing container 2 from the etching solution; d) Rinsing container 2 with water, isopropanol and iso-dodecane; e) Silanizing the container 2 by immersing the container in a silanizing solution containing iso-dodecane and dichlorodimethylsilane, wherein the silanizing solution is moved at least temporarily relative to the container 2; f) Removing container 2 from the silanization solution; g) Rinsing container 2 with isopropanol and water; h) Drying of container 2 with the application of heat at a minimum of 60°C.

[0052] The surface area of ​​the dielectric container, preferably made of soda-lime glass, is increased by etching. The etching solution used produces a kind of "egg-cup pattern" in the ultrastructure of the glass surface. The surface of the container can be etched, for example, by hydrofluoric acid and hydrofluoric acid salts in combination with strong inorganic acids, preferably sulfuric acid.

[0053] The silicon from the silicon dioxide in the glass mixture is converted into silicon hexafluoride. This is gaseous and escapes. Simultaneously, fluorides react with calcium compounds in the glass mixture to form calcium fluoride, which is deposited on the surface. These deposits are mobilized by the sulfuric acid in the etching solution; by agitating the etching mixture, they are rinsed from the glass surface. At the same time, ammonium hydrogen difluoride in the etching solution accelerates this process.

[0054] Subsequently, the glass surface, prepared by etching, is silanized with dichlorodimethylsilane. The compound dichlorodimethylsilane reacts chemically with the glass surface, releasing hydrogen chloride. This process binds dimethylsilane units to the surface, leading to further hydrophobization. Simultaneously, the surface resistance increases, and the charge density at the surface is enhanced. Other silanization reagents (e.g., n-octyltriethoxysilanes) are less effective than dichlorodimethylsilane in achieving the desired surface modification. Furthermore, the silanization products produced by dichlorodimethylsilane are irreversibly bound to the glass surface, ensuring long-term stability of the surface silanization.

[0055] The plasma reaction taking place at the Helmholtz layer is enhanced by this surface modification, so that the yield - especially of the disinfecting hydroxyl radicals - is increased without changing the potential difference of the plasma reaction.

[0056] The rinsing in step a) can be carried out by rinsing the glass components twice with acetone and then rinsing the glass components twice with demineralized water.

[0057] The acid treatment of the glass components in step b) can be carried out with an etching solution containing: - 1000 mL water H2O, demineralized water or distilled water - 500 mL sulfuric acid H2SO4 with a mass fraction w of preferably about 48% - 500 mL hydrogen fluoride HF with a mass fraction w of preferably about 40% - 100 g ammonium hydrogen difluoride (NH4)HF2 - 10 g potassium fluoride KF

[0058] These chemicals are mixed in the order listed above. They are added slowly while stirring continuously, for example with a magnetic stirrer. The ammonium hydrogen difluoride and potassium fluoride dissolve after hydrofluoric acid has been present in the solution.

[0059] The solution should be cooled to room temperature before etching.

[0060] The glass components are immersed in this etching solution. It is recommended to use approximately 2000 mL of etching solution for approximately 600 g of glass material. The etched container 2 can be a type 231 laboratory test tube made of soda-lime glass with a wall thickness of approximately 0.7 mm ±0.2 mm. Borosilicate glass is also suitable. This can have a thinner wall thickness in the range of 0.4 to 0.5 mm.

[0061] The exposure time of container 2 in the etching solution should be approximately 10 minutes for soda-lime glass and 60 minutes for borosilicate glass. The mixture can be kept in slow motion using a shaker plate. This can be done at approximately 5 oscillations per minute.

[0062] Rinsing in step d) can be carried out by rinsing the glass components three times with demineralized water. This can then be followed by rinsing the glass components twice with isopropanol and once with iso-dodecane.

[0063] The glass container, roughened and cleaned by etching, is subsequently made hydrophobic. This is done in step e) by silanizing the glass components through immersion in a silanizing solution. This silanizing solution preferably contains: - 1900 mL iso-dodecane - 100 mL dichlorodimethylsilane C2H6Cl2Si.

[0064] For silanization, approximately 2000mL of silanization solution can also be used for approximately 600g of glass material in the form of laboratory test tubes type 231 made of soda-lime glass with a wall thickness of approximately 0.7 mm ±0.2 mm or made of borosilicate glass (i.e., 231 stand-up tubes).

[0065] The exposure time for silanization should be approximately 60 minutes. During this time, the mixture should be kept in slow motion using a shaking plate. Approximately 5 vibrations per minute have proven suitable for this purpose.

[0066] The silanized glass container 2 is rinsed in step g). For this purpose, the glass components are preferably rinsed twice with isopropanol and three times with deionized water.

[0067] In step h), the glass components are then dried in a drying oven at 60°C for about 8 hours.

[0068] The surface modification is resistant to chemicals with the exception of fluorides and hydrofluoric acid. Furthermore, the surface modification is thermally resistant up to approximately 600°C.

[0069] An external electrode lead 11 is connected to the external electrode 10, which, together with the internal electrode lead 4, is connected to a control electronics unit 12. This control electronics unit 12 is supplied with a supply voltage UV and is configured to apply a high voltage to the internal and external electrodes 3 and 10.

[0070] The high voltage applied to the inner and outer electrodes 3, 10 should be less than 2 kV and preferably in the range of 1.45 to 1.75 kV. The current of the overall system can, for example, be between 180 and 230 mA. The high voltage can be an alternating voltage. The sinusoidal frequency of the alternating voltage can preferably be in the range of 38 kHz. This reduces the formation of harmful nitrogen oxides (NOx).X prevents this and ionizes the surrounding air in such a way that hydroxyl radicals are formed.

[0071] At higher voltages in the range of approximately 2 to 3 kV, ambient air is ionized through the formation of ozone. Higher voltages above 3 kV then lead to the harmful formation of nitrogen oxides (NOx). X .

[0072] The ambient air ionized by the device can then be used for disinfection in a variety of ways.

[0073] The device can be used to purify room air of harmful bacteria, viruses, and fungal spores. It is particularly advantageous, however, when used to generate an ionized airflow into which aerosols are introduced, and when this aerosol-containing, ionized airflow is then used for disinfection. In this context, the device can be used for patient care, for example, to deliver aerosol-containing ionized air into the lungs, and especially into the alveolar ducts, via a breathing tube, in order to treat bacterial and viral lung diseases.

[0074] For this purpose, the air should be heated, but not exceeding 37 °C. The particle size of the aerosols should be as small as possible, in the range of 0.2 to 0.4 µm. This ensures that the water input is not excessive.

[0075] The aerosols, in combination with the ionized air, prevent harmful drying of the skin.

[0076] Fig. Figure 3 shows a sketch of part of the device 1 with the electrically conductive material 7 introduced into the container 2.

[0077] It becomes clear that the inner electrode 3 forms the stripped end of an electrical conductor 4, which is surrounded by a silicone sheath 5. This silicone sheath 5 rests with its end face on the silicone disc 8, so that after the electrically conductive material 7 is poured into the container 2, the electrically conductive material 7 is compressed by the silicone disc 8 through the silicone sheath 5 by force. The remaining gap between the silicone sheath 5 and the free end of the container 2 is then filled with potting compound 9.

[0078] Fig.Figure 4 shows a sketch of a disinfection device with the ionization device 1 described above and a mixing box 15 for aerosol supply.

[0079] The ionization device 1 is arranged in a pipe section 13 or container. The ambient air L is passed through the pipe section 13, for example by a fan (not shown), and ionized by operation of the ionization device 1 so that hydroxyl radicals -OH are formed. These are fed into a mixing box 15, into which fine water-containing aerosols continue to flow.

[0080] It is advantageous, especially for medical applications involving delivery into the respiratory tract, that the aerosols have a particle size of less than 0.4 µm.

[0081] The aerosols are generated in an aerosol generator 14 from water or aqueous solution, especially pure water, introduced therein. This can be done by ultrasonic nebulization, atomization using compressed air, and the like.

[0082] The aerosol-containing air mixture, enriched with hydroxyl radicals, is then extracted for disinfection. It can be directed into a housing, for example for hand disinfection, into the room volume of a building for air purification, into a tube for introduction into a patient's airways, etc.

Claims

[1] Device (1) for ionizing an air stream comprising a container (2) made of electrically insulating material, an inner electrode (3) arranged in the interior of the container (2) and an outer electrode (10) arranged on the outside of the container (2), with control electronics (12) which is connected to the inner electrode (3) and the outer electrode (10) for supplying a voltage, wherein the inner and / or outer surface of the container (2) is acid-treated and an electrically conductive material (7) with the inner electrode (3) inserted into the electrically conductive material (7) is placed in the interior of the container (2) and the inner electrode (3) is surrounded by the electrically conductive material (7), characterized by , that the inner and / or outer surface of the container (2) is made hydrophobic by silanization. [2] Device (1) according to claim 1, characterized by, that the electrically conductive material is a granulate (7) which contains carbon-containing particles. [3] Device (1) according to claim 2, characterized by , that the granules (7) are a coal powder with a mean particle size of at most 450 µm. [4] Device (1) according to claim 2, characterized by , that the granules (7) are a coal powder with a particle size distribution in the range of 1 to 100 µm. [5] Device (1) according to claim 1 or 2, characterized by , that the electrically conductive material is a granulate (7) containing aluminium, copper, stainless steel, titanium, graphite and / or magnesium particles. [6] Device (1) according to claim 5, characterized by , that the aluminium-containing, copper-containing, stainless-containing, titanium-containing, graphite-containing and / or magnesium-containing particles of the granules (7) have a mean particle size in the range of 10 to 450 µm. [7] Device (1) according to any one of the preceding claims, characterized by that the container (2) is made of a dielectric material, preferably glass or ceramic. [8] Device (1) according to any one of the preceding claims, characterized by , that the container (2) has a wall thickness in the range of 0.5 to 1.0 mm, preferably in the range of 0.6 to 0.8 mm. [9] Device (1) according to any of the preceding claims, characterized by , that the outer electrode (10) has a grid structure with a grid size in the range of 0.85 mm (Mesh 20) to 0.456 mm (Mesh 38), preferably 0.60 mm (Mesh 30). [10] Device (1) according to any of the preceding claims, characterized by , that the effective length of the container (2) is in the range of 25 to 35 mm and preferably 30 mm. [11] Device (1) according to any of the preceding claims, characterized by, that the length of the outer electrode (10) is in the range of 20 to 30 mm and preferably 25 mm. [12] Device (1) according to any of the preceding claims, characterized by , that the electrically conductive material (7) is covered with a silicone cover (8) and an electrode lead (4) connected to or forming the inner electrode (3) is passed through the silicone cover (8), wherein a silicone sheath (5) of the electrode lead (4) adjoins the silicone disc (8). [13] Method for manufacturing a device for ionizing an air stream according to any one of the preceding claims, characterized byEtching of the inner and / or outer surface of the container (2) by means of acid treatment and silanization of this acid-treated inner and / or outer surface of the container (2), wherein an inner electrode (3) is subsequently inserted into the container (2) roughened by the acid treatment and hydrophobized by silanization and a conductive material (7) surrounding the inner electrode (3) is introduced into the interior of the container (2). [14] Method according to claim 13, characterized by the steps: a) Rinsing the container (2) with an acetone-containing solution and with water; b) Acid treatment of the container (2) by immersing the container (2) in an aqueous etching solution, whereby the etching solution is moved at least temporarily relative to the container (2); c) Removing the container (2) from the etching solution; d) Rinsing the container (2) with water, isopropanol and iso-dodecane; e) Silanizing the container (2) by immersing the container in a silanizing solution containing iso-dodecane and dichlorodimethylsilane, wherein the silanizing solution is moved at least temporarily relative to the container (2); f) Removal of the container (2) from the silanization solution; g) Rinsing the container (2) with isopropanol and water; h) Drying the container (2) by applying heat at a minimum of 60°C. [15] Method according to claim 14, characterized by , that the acid treatment of the container (2) in step b) is carried out for at least 10 minutes, the silanization of the container (2) in step e) is carried out for at least 60 minutes and / or the drying of the container (2) in step h) is carried out for at least 8 hours.

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