Low-frequency ozone generator

Abstract

Ozone generator device comprising: - an ozone generator unit (27, 45) comprising: o a high-voltage electrode unit (16, 36); o a first (23, 43) and a second dielectric element (24, 44); o a first (14, 34) and a second earth electrode (15, 35); wherein the high-voltage electrode unit is positioned between the first and second dielectric elements, - wherein the generator unit is designed to be operated in an operating frequency range between 30 and 40 kHz; and the device further comprises: a low-frequency high-voltage AC power supply, such as a transformer assembly, configured to provide between 50 and 800 watts at a frequency between 30 and 40 kHz to the ozone generator unit; wherein the first and second dielectric elements are positioned at a distance from the high-voltage electrode unit within a range between 0.01 and 0.1 millimeters, such as between 0.01 and 0.075 millimeters.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to an ozone generator device designed to operate in an operating frequency range between 25 and 40 kHz.

[0002] The present invention further relates to a transformer assembly, such as a high-power transformer, which is designed or suitable for providing power in a frequency range between 25 and 40 kHz. BACKGROUND OF THE INVENTION

[0003] A successful ozone water treatment installation depends on the ability to ensure the required amount of ozone in the water at all times.

[0004] Proper removal of heavy metals from contaminated groundwater, effective removal of colloidal solids, dissolved organic compounds and the conversion of nitrite to nitrate in aquaculture systems, as well as efficient solutions for urban water treatment with ozone depend on the ability to ensure the required amount of ozone in the water at all times.

[0005] Ozone generating devices are preferably operated at a frequency above the range audible to humans, i.e. in the frequency range between 15 and 25 kHz, as disclosed, for example, in WO 2008 / 074767.

[0006] Operation at high frequency is desirable because it has the advantage that smaller operating voltages are required for a given input power compared to operation at low frequency, as disclosed, for example, by Kogelschatz in Plasma Chemistry and Plasma Processing, Vol 23, (1): (1-46).

[0007] However, high-frequency ozone generators do not always ensure the release of the required amount of ozone. For example, the actual release of ozone, i.e., the concentration of released ozone, may in some cases be less than a specified value or below acceptable limits.

[0008] Thus, an improved ozone generator would be advantageous, and in particular, a more efficient and reliable ozone generator device capable of ensuring the required amount of ozone in the water to be treated at all times would be advantageous. OBJECT OF THE INVENTION

[0009] An object of the present invention is to provide an ozone generator device capable of ensuring the required amount of ozone in the water to be treated at any time.

[0010] Yet another object of the present application is to provide a transformer assembly for supplying an ozone generator device capable of ensuring at any time the required amount of ozone in the water to be treated.

[0011] An object of the present invention can also be seen in providing an alternative to the prior art.

[0012] In particular, a further object of the present invention can be seen in providing an ozone generator device and a transformer assembly for supplying an ozone generator device, which solve the above-mentioned problems of the prior art by being designed to be operated in an operating frequency range between 25 and 40 kHz. SUMMARY OF THE INVENTION

[0013] Thus, the above-mentioned object and some other objects are to be achieved in a first aspect of the invention by providing an ozone generator device comprising: an ozone generator unit having a high voltage electrode unit, first and second dielectric elements, and first and second ground electrodes.

[0014] The generator unit is designed or suitable to be operated in an operating frequency range between 25 and 40 kHz.

[0015] For example, the operating frequency can be between 30 and 40 kHz, such as between 31 and 37 kHz.

[0016] In their search for optimizations in the field of ozone generation, the inventors found that decreasing the operating frequency increases the productivity of the ozone generator.

[0017] In general, operation at low frequency is not desirable because operating an ozone generator at high frequency has the advantage of lower operating voltages for a given input power.

[0018] Furthermore, decreasing the operating frequency increases the audible noise generated by the ozone generator unit. In fact, ozone generation devices are preferably operated at a frequency well above the human audible range.

[0019] In their search for optimizations in the field of ozone generation, the inventors investigated the operating frequency range in relation to the undesirable background noise generated during operation and in relation to the optimal ozone release.

[0020] The inventors thus identified a frequency range in which a correspondence between the target value and the actual value of ozone release is optimized for minimal audible operational disturbance.

[0021] The ozone generator device according to the first aspect of the invention may further comprise a low frequency high voltage AC power supply, such as a high power transformer or transformer assembly, configured or suitable to provide between 50 and 800 watts at a frequency between 25 and 40 kHz to the ozone generator unit.

[0022] For example, the high voltage AC power supply may be configured or adapted to provide between 50 and 800 watts at a frequency between 30 and 40 kHz, such as preferably between 31 and 37 kHz.

[0023] The presence of a high-voltage AC power supply designed or capable of providing between 50 and 800 watts enables the ozone generator unit to operate at a frequency of between 25 and 40 kHz.

[0024] The high voltage AC power supply according to the invention may be referred to herein as a high power transformer, a transformer or a transformer assembly.

[0025] With respect to the structure of the ozone generator unit, such as the high-voltage electrode unit, the first and second dielectric members, and the first and second ground electrodes, reference is made to the structures and elements disclosed in WO 02 / 20398, which are incorporated herein by reference.

[0026] The first and second dielectric elements may be polymer layers, such as a thin layer of polymer materials, e.g., a layer of polytetrafluoroethylene (PTFE).

[0027] In some embodiments, the high voltage electrode unit is located between the first and second dielectric elements.

[0028] The first and second dielectric elements may be positioned at a distance from the high-voltage electrode unit within a range between 0.01 and 0.5 millimeters, such as between 0.01 and 0.4 millimeters, for example between 0.01 and 0.3 millimeters, such as between 0.01 and 0.1 millimeters.

[0029] In some further embodiments, the first and second dielectric elements may be spaced from the high voltage electrode assembly by one or more spacer elements.

[0030] The first and second dielectric elements may be spaced from the high voltage electrode unit by the one or more spacer elements within 0.01 and 0.5 millimeters, such as between 0.01 and 0.4 millimeters, for example between 0.01 and 0.3 millimeters, such as between 0.01 and 0.1 millimeters.

[0031] The first and second dielectric elements may be arranged on both sides of the high-voltage electrode.

[0032] In some embodiments, the first and second ground electrodes define first and second reaction chambers with the first and second dielectric elements.

[0033] The first and second reaction chambers may each have an inlet for supplying oxygen gas or oxygen-containing gas and an outlet for releasing ozone gas.

[0034] The outer surface of the first and second reaction chambers may have cooling elements, such as cooling fins.

[0035] In some embodiments, air cooling may be used alone or in combination with water cooling, increasing the efficiency of the ozone generator unit.

[0036] In some other embodiments, water cooling alone may be used to cool the ozone generator unit.

[0037] The high-voltage electrode may be arranged as a metallic coating on the first and / or the second dielectric element.

[0038] In some further embodiments, the high voltage electrode is a metal foil or a metal layer.

[0039] In some further embodiments, the first and second dielectric elements may be in contact with an inner surface of the first and second reaction chambers.

[0040] The above-mentioned specific configuration has the advantage that heat generated during ozone generation can be dissipated more efficiently as heat exchange between the cooled earth electrodes that are part of the first and second reaction chambers and the first and second dielectric elements because the contact with the inner surface of the first and second reaction chambers is more efficient.

[0041] In a second aspect, the invention relates to an ozone generator device which is designed and configured to carry out a method, the method comprising: operating the ozone generator device at a frequency between 25 and 40 kHz, such as between 30 and 40 kHz.

[0042] In some embodiments according to the second aspect of the invention, operating the ozone generator device according to the first aspect of the invention comprises: supplying a fluid stream containing oxygen gas to the ozone generator unit; regulating the fluid stream containing oxygen gas; regulating a power supplied from a power supply device to the ozone generator at a frequency between 25 and 40 kHz, such as between 30 and 40 kHz.

[0043] In a third aspect, the invention relates to an ozone generator device which is designed and configured to carry out a method, the method comprising operating the ozone generator device at a frequency between 25 and 40 kHz, such as between 30 and 40 kHz.

[0044] In some embodiments of the ozone generator device configured and arranged to perform a method according to the third aspect of the invention, operating the ozone generator comprises: supplying a fluid stream containing oxygen gas to the ozone generator; regulating the fluid stream containing oxygen gas; regulating a power supplied by a power supply device to the ozone generator at a frequency between 25 and 40 kHz, such as between 30 and 40 kHz.

[0045] In some further embodiments of the first, second or third aspect of the invention, the operating frequency is a frequency between 31 and 40 kHz, such as a frequency between 32 and 35 kHz.

[0046] In a fourth aspect, the invention relates to a transformer assembly or a transformer, such as a high power transformer, which is designed or suitable to supply electrical power within a frequency range between 25 and 40 kHz, such as between 30 and 40 kHz.

[0047] The transformer assembly according to the fourth aspect may include a ferrite cup-type core surrounding a primary winding and a secondary winding. The primary winding may have fewer than 14 turns, and the secondary winding may have more than 107 turns. The ferrite cup-type core may have an air gap of less than 2.0 mm.

[0048] In some embodiments, the ferrite shell type core comprises at least two parts separated from each other by an air gap of less than 2.0 mm.

[0049] The inventors designed the high-performance transformer taking into account that the operating frequency of the ozone generator unit depends on the capacitance of the reactor and the inductance on the secondary side of the high-voltage transformer. The inductance on the primary side of the high-voltage transformer and the series inductance also have a certain influence on the operating frequency of the ozone generator unit.

[0050] To modify the operating frequency, the invention uses a transformer assembly with increased inductance.

[0051] An approximation of the inductance can be calculated using the following formula: L=N2∗μ0∑(IAe)μe+GAe

[0052] µ 0is a physical constant and cannot be changed. The mechanical dimensions of the transformer assembly are limited by the size of the ozone generator unit. In addition, the ferrite core in the transformer assembly also has predefined dimensions that cannot be changed.

[0053] In practice, according to the formula above, it means that no modification of ∑(lAe) (geometric constant of the nucleus) and A e (area of ​​the core) is possible. µ e is the constant of the material used, which is ferrite according to the state of the art.

[0054] The solution of the invention is to change N (number of turns of the primary winding) and G (air gap of the core).

[0055] However, the limitation of the mechanical dimensions of the generator unit means that there is no possibility to increase the number of turns in the secondary winding in the transformer without decreasing the number of turns in the primary winding.

[0056] The solution of the invention was to modify the number of turns in the primary winding, for example by reducing it by a certain number, such as 1, 2, 3, 4, or 5 turns, compared to the value currently used in transformer assemblies operating at ≈45 kHz, which is, for example, approximately 14 turns. This provided more possibilities for modifying the number of turns in the secondary winding, for example by increasing it by a certain number, such as 1, 2, 3, 4, or 5 turns, compared to the value currently used in transformer assemblies operating at ≈45 kHz, which is, for example, approximately 107 turns.

[0057] Reducing the gap in the transformer increases the magnetic flux in the core. Lowering the frequency increases the magnetic flux, which leads to an increase in core losses. On the other hand, lowering the frequency reduces the number of changes in the direction of the flux. On the other hand, this reduces losses. In this way, the gap has been modified, such as reduced by 0.25, 0.5, 0.75, 1, 1.1, 1.2 mm compared to the value currently used in transformer assemblies that have an operating frequency of ≈45 kHz, which is approximately 2.1 to 2.2 mm, for example.

[0058] Thus, in some embodiments, the invention relates to a transformer assembly comprising a ferrite cup type core surrounding a primary winding and a secondary winding, wherein the primary winding has a number of turns less than 14 and the secondary winding has a number of turns greater than 107, and the ferrite cup type core has an air gap less than 2 mm.

[0059] By reducing the gap and increasing the number of turns in the secondary winding and decreasing the number of turns in the primary winding, the operating frequency decreased from ≈45 kHz to ≈30 kHz.

[0060] This modification may slightly increase the operating temperature. However, the increase in operating temperature can be mitigated with improved cooling solutions.

[0061] The first, second, third and further aspects and embodiments of the present invention may each be combined with any of the other aspects and embodiments.

[0062] These and other aspects of the invention will become apparent from and be explained with reference to the embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The ozone generator, the method for operating the ozone generator, and the transformer assembly according to the invention will now be described in more detail with reference to the accompanying drawings. The drawings illustrate one possible implementation of the present invention and are not to be considered limiting of other possible embodiments falling within the scope of the appended set of claims. Fig. 1 shows a cross-section of an ozone generator unit according to some embodiments of the invention. Fig. 2 shows a cross section of an ozone generator unit according to some further embodiments of the invention. Fig. Figure 3 shows a graphical representation of the operating frequency versus the weighted audible noise and the relationship between the setpoint and the actual value of ozone production. Fig. 4 is an exploded view of the transformer assembly according to some embodiments of the invention. Fig. 5 is a perspective view of the transformer assembly according to some embodiments of the invention. Fig. 6 is a flowchart of a method performed with an ozone generator device according to some embodiments of the invention. DETAILED DESCRIPTION OF AN EMBODIMENT

[0064] Fig. 1 shows an ozone generator unit 27 having a first PTFE layer 23 and a second PTFE layer 24 surrounding a high voltage electrode 16.

[0065] The first and a second reaction chamber in which ozone is generated are bounded by the first PTFE layer 23 and the second PTFE layer 24 on one side and the inner surface of the housing or the earth electrodes 14 and 15, respectively.

[0066] Oxygen gas enters the ozone generator unit 27 via inlets 19 and 20 and is subjected to a corona discharge in the first and second reaction chambers, resulting in the formation of ozone gas, which is released through ozone outlets 21 and 22, respectively.

[0067] The housing or the ground electrodes 14 and 15 are cooled by water flowing into water cooling chambers 11 and 13. The water cooling chambers 11 and 13 are defined by recesses on the outer surface of the ground electrodes 14 and 15 covered by covers 10 and 12.

[0068] Stainless steel meshes or sheets 25 and 26 are positioned between the inner surface of the ground electrodes 14 and 15 and the first PTFE layer 23 and the second PTFE layer 24. The stainless steel meshes or sheets 25 and 26 are structures that promote the corona effect, which promotes the discharge between the electrodes.

[0069] Support rings 17 and 18 made of PTFE are arranged between the earth electrodes 14 and 15.

[0070] The PTFE support rings can function as spacer elements and ensure the formation of reaction chambers between the earth electrodes and the high-voltage electrode.

[0071] Fig. Figure 2 shows an ozone generator unit 45 having a first PTFE layer 43 and a second PTFE layer 44 surrounding a high voltage electrode 36.

[0072] The first and a second reaction chamber in which ozone is generated are bounded by the first PTFE layer 43 and the second PTFE layer 44 on one side and the inner surface of the housing or the earth electrodes 34 and 35, respectively.

[0073] Oxygen gas enters the ozone generator unit 45 via inlets 39 and 40 and is subjected to a corona discharge in the first and second reaction chambers, resulting in the formation of ozone gas which is released through ozone outlets 41 and 42, respectively.

[0074] The housing or the ground electrodes 34 and 35 are cooled by cooling with water flowing into water cooling chambers 31 and 33. The water cooling chambers 31 and 33 are defined by recesses on the outer surface of the ground electrodes 34 and 35 covered by covers 30 and 32.

[0075] PTFE support rings 37 and 38 are arranged between the earth electrodes 34 and 35.

[0076] In the ozone generator unit 45, the first and second PTFE layers 43 and 44 are in contact with an inner surface of the first and second reaction chambers, that is, with the inner surface of the ground electrodes 34 and 35.

[0077] This configuration allows for improved and efficient cooling of the PTFE layers as they are in contact with the inner surface of the earth electrodes, which is externally cooled with water.

[0078] Fig. Figure 3 shows a graphical representation of the operating frequency versus the weighted audible noise and the relationship between the setpoint and the actual value of ozone production.

[0079] The X-axis represents the operating frequency of an ozone generator according to the first aspect of the invention in Hz.

[0080] The Y 1 -axis is a weighted value of the reduction of audible noise in dBa.

[0081] Line 1 represents a collection of data from ozone generators operating at different frequencies versus noise reduction.

[0082] It can be seen that increasing the frequency between 10 kHz and 30 kHz produces a significant reduction in noise, down to -32.5 dBa. A further increase to 40 kHz provides a further reduction down to -37.5 dBa. A further increase in the operating frequency does not significantly reduce the noise generated by the ozone generator that is audible to humans.

[0083] The Y 2 -axis is the ratio between an actual value of ozone production and a target value of ozone production O av / O sv at a concentration of 200 g O 3 / Nm 3 Ozone, at 2 bar, 100% ozone release capacity.

[0084] The value 100 on the Y2 axis represents the state when the setpoint value corresponds to the actual value, thus for a setpoint of 200 g O 3 / Nm 3 the actual value of released ozone 200 g O 3 / Nm 3Values ​​lower than 100 correspond to conditions where the setpoint is higher than the actual ozone release, i.e. less ozone is released compared to the setpoint.

[0085] Values ​​higher than 100 correspond to conditions where the setpoint is lower than the actual ozone release, i.e. more ozone is released compared to the setpoint.

[0086] Line 2 shows the correspondence between the setpoints and the actual values ​​depending on the operating frequency.

[0087] It can be seen that the higher the operating frequency, the worse the correspondence between the setpoint and the actual value of ozone released.

[0088] In fact, at high frequency, e.g., at 60 kHz, the correspondence value of 90 means that at a setpoint of 200 g O 3 / Nm 3 only 180 g O 3 / Nm 3 be released.

[0089] Reducing the operating frequency improves the correspondence between the setpoint and the actual value of ozone released.

[0090] For example, at an operating frequency of 30 kHz, the correspondence value of 102 means that at a setpoint of 200 g O 3 / Nm 3 204 g O 3 / Nm 3 be released.

[0091] Within the acceptable limits of deviation between nominal and actual value, i.e. 100 + / - 2, it was surprisingly found that the operating frequency between 30 and 40 kHz is the frequency that provided the lowest audible noise, i.e. the highest reduction in dBa, i.e. between -32.5 dBa and -37.5 dBa.

[0092] The inventors therefore designed the ozone generator to operate at a frequency between 30 and 40 kHz.

[0093] In Fig. 4, the transformer assembly 5 according to some embodiments of the invention comprises a ferrite core consisting of two parts 3 and 6 separated by a gap 7 and primary and secondary windings 4 and 8.

[0094] Fig. 5 is a perspective view of the transformer assembly 5 shown in an exploded view in Fig. 4 is shown.

[0095] Fig. 6 is a flowchart of a method of operating an ozone generator 9 performed with the ozone generator device, wherein the ozone generator device according to the first aspect of the invention comprises operating the ozone generator device at a frequency between 25 and 40 kHz, such as between 30 and 40 kHz.

[0096] Operating the ozone generator includes the following: - S1, supplying a fluid stream containing oxygen gas to the ozone generator; - S2, regulating the flow of fluid containing oxygen gas; - S3, regulating a power supplied to the ozone generator by a power supply device at a frequency between 25 and 40 kHz, such as between 30 and 40 kHz.

[0097] Although the present invention has been described in connection with the specified embodiments, this is not to be construed as limiting the examples presented in any way. The scope of the present invention is indicated by the appended claims. In the context of the claims, the terms "comprise", "has", "comprise" or "includes" do not exclude other possible elements or steps. Nor should the mention of references such as "a" or "an" etc. be construed as excluding the plural. The use of reference numerals in the claims with reference to elements listed in the figures is also not to be construed as limiting the scope of the invention.Furthermore, individual features mentioned in different claims may possibly be advantageously combined, and the mention of these features in different claims does not exclude the possibility of a combination of features being possible and advantageous. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2008 / 074767

[0005] WO 02 / 20398

[0025] Cited non-patent literature

[0000] Plasma Chemistry and Plasma Processing, Vol 23, (1): (1-46)

[0006]

Claims

[1] Ozone generator device comprising: - an ozone generator unit (27, 45) comprising: o a high-voltage electrode unit (16, 36); o a first (23, 43) and a second dielectric element (24, 44); o a first (14, 34) and a second earth electrode (15, 35); wherein the high-voltage electrode unit is positioned between the first and second dielectric elements, - wherein the generator unit is designed to be operated in an operating frequency range between 30 and 40 kHz; and the device further comprises: a low-frequency high-voltage AC power supply, such as a transformer assembly, configured to provide between 50 and 800 watts at a frequency between 30 and 40 kHz to the ozone generator unit; wherein the first and second dielectric elements are positioned at a distance from the high-voltage electrode unit within a range between 0.01 and 0.1 millimeters, such as between 0.01 and 0.075 millimeters. [2] Ozone generator device according to one of the preceding claims, wherein the first and second dielectric elements are spaced from the high voltage electrode unit by one or more spacer elements. [3] An ozone generator device according to any preceding claim, wherein the first and second dielectric members are disposed on both sides of the high voltage electrode. [4] An ozone generator device according to any preceding claim, wherein the first and a second ground electrode define first and a second reaction chamber having the first and second dielectric members. [5] Ozone generator device according to one of the preceding claims, wherein the high voltage electrode is arranged as a metallic coating on the first and second dielectric elements. [6] The ozone generator device according to any one of claims 1 to 4, wherein the high voltage electrode is a metal foil or a metal sheet. [7] Ozone generator device according to one of claims 4 to 6, wherein the first and second reaction chambers each have at least one inlet (19, 20, 39, 40) for supplying oxygen gas or oxygen-containing gas and at least one outlet (21, 22, 41, 42) for releasing ozone gas. [8] Ozone generator device according to one of claims 4 to 7, wherein an outer surface of the first and second chambers has cooling elements, such as cooling fins. [9] An ozone generator device according to any preceding claim, wherein the first and second dielectric members are in contact with an inner surface of the first and second reaction chambers. [10] Ozone generator apparatus according to any one of the preceding claims, wherein the transformer assembly is a high power transformer. [11] Ozone generator device according to one of the preceding claims, wherein the transformer assembly is a high-power transformer comprising a ferrite cup type core surrounding a primary winding and a secondary winding, the primary winding having a number of turns lower than 14 and the secondary winding having a number of turns higher than 107, and the ferrite cup type core having an air gap smaller than 2 mm.

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