Low frequency ozone generator

Abstract

To provide an ozone generator apparatus able to secure the required level of ozone in the water to be treated at all times, a method of operating the ozone generator apparatus, and a transformer assembly.SOLUTION: An ozone generator apparatus comprises an ozone generator unit comprising a high voltage electrode unit, a first and second dielectric element, and a first and second earth electrode. The high voltage electrode unit is located between the first and the second dielectric element. The ozone generator unit is configured to be operated at an operational frequency range between 30 and 40 kHz, and a low frequency, high voltage AC power supply, being a transformer assembly, configured to provide between 50 and 800 Watts at a frequency between 30 and 40 kHz to the ozone generator unit.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an ozone generator configured to operate in the operating frequency range of 25 to 40 kHz.

[0002] The present invention also relates to a method for operating an ozone generator at a frequency between 25 and 40 kHz.

[0003] The present invention also relates to a transformer assembly, such as a high power transformer, configured or adapted to provide power in the frequency range of 25 to 40 kHz. [Background technology]

[0004] The suitability of an ozone water treatment system depends on its ability to consistently maintain the required level of ozone in the water.

[0005] Accurate removal of heavy metals from contaminated groundwater, adequate removal of colloidal solids and dissolved organic compounds, conversion of nitrite to nitrate in aquaculture systems, and efficient solutions to municipal ozone water treatment problems depend on the ability to ensure the required levels of ozone are always present in the water.

[0006] The ozone generator is preferably operated at frequencies above the human hearing range, ie in the frequency range of 15-25 kHz, as disclosed, for example, by WO 2008 / 074767.

[0007] High frequency operation is also desirable because it has the advantage of requiring a lower operating voltage for a given input power compared to low frequency operation, as disclosed, for example, in Kogelschatz, Plasma Chemistry and Plasma Processing, Vol 23, (1):(1-46).

[0008] However, ozone generators operating at high frequencies do not always guarantee the required level of ozone emission, for example the actual emission of ozone, i.e. the concentration of emitted ozone, may in some cases be lower than the set value or below the permissible limit.

[0009] Therefore, improvements in ozone generators would be advantageous, and in particular, more efficient and reliable ozone generating devices that can consistently ensure the required levels of ozone in the water being treated would be advantageous. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide an ozone generator capable of always ensuring a required level of ozone in the water to be treated.

[0011] It is a further object of the present invention to provide a method of operating an ozone generator which ensures that the required level of ozone is always present in the water being treated.

[0012] It is a further object of the present application to provide a transformer assembly for supplying power to an ozone generating device that is capable of consistently ensuring a required level of ozone in the water being treated.

[0013] An object of the present invention may also be seen as providing an alternative to the prior art.

[0014] In particular, a further object of the present invention can be seen to be to provide an ozone generator, a transformer assembly for powering the ozone generator, and a method for operating the ozone generator that is configured to operate in an operating frequency range of 25-40 kHz, thereby solving the above-mentioned problems of the prior art. [Means for solving the problem]

[0015] It is therefore intended that the above objects and several other objects may be obtained in a first aspect of the present invention by providing an ozone generator comprising an ozone generating section comprising a high voltage electrode section, first and second dielectric elements, and first and second earth electrodes.

[0016] The generating section is configured or adapted to operate in an operating frequency range of 25 to 40 kHz.

[0017] For example, the operating frequency may be 30 to 40 kHz (such as 31 to 37 kHz).

[0018] In their search for optimization in the field of ozone generation, the inventors have realized that reducing the operating frequency increases the productivity of the ozone generator.

[0019] Generally, operating the ozone generator at a higher frequency has the advantage of lowering the operating voltage for a given input power, so operation at a lower frequency is undesirable.

[0020] Furthermore, lowering the operating frequency increases the audible noise generated by the ozone generating unit. In fact, it is desirable to operate ozone generators at frequencies well above the range of human hearing.

[0021] In their search for optimization in the field of ozone generation, the inventors have investigated the operating frequency range with respect to the unwanted background noise generated during operation and the optimal amount of ozone released.

[0022] As a result, the inventors have identified a frequency range in which the correspondence between setpoint and measured ozone release is optimized while minimizing audible interference from operation.

[0023] The ozone generator according to the first aspect of the present invention may further comprise a low frequency, high voltage AC power source, such as a high power transformer or transformer assembly, configured or adapted to provide 50-800 watts at a frequency of 25-40 kHz to the ozone generating portion.

[0024] For example, the high voltage AC power source may be configured or adapted to provide 50-800 watts at a frequency such as 30-40 kHz, preferably 31-37 kHz.

[0025] A high voltage AC power supply configured or adapted to provide 50-800 watts is capable of providing an operating frequency of 25-40 kHz to the ozone generator.

[0026] The high voltage AC power supply of the present invention may be referred to herein as a high power transformer, a transformer, or a transformer assembly.

[0027] With regard to the structure of the ozone generating section, such as the high voltage electrode section, the first and second dielectric elements, and the first and second earth electrodes, please refer to the structures and elements disclosed in WO 02 / 20398, which is incorporated herein by reference.

[0028] The first and second dielectric elements may be thin layers of polymeric material, for example polymer layers such as polytetrafluoroethylene (PTFE) sheets.

[0029] In some embodiments, the high voltage electrode portion is disposed between the first dielectric element and the second dielectric element.

[0030] The first and second dielectric elements may be disposed at a distance within a range of 0.01 to 0.5 mm (eg, 0.01 to 0.4 mm, 0.01 to 0.3 mm, 0.01 to 0.1 mm, etc.) from the high voltage electrode portion.

[0031] In some further embodiments, the first and second dielectric elements may be spaced from the high voltage electrode portion by one or more spacer elements.

[0032] The first and second dielectric elements may be spaced from the high voltage electrode portion by one or more spacer elements at a distance within a range of 0.01 to 0.5 millimeters (e.g., 0.01 to 0.4 millimeters, 0.01 to 0.3 millimeters, 0.01 to 0.1 millimeters, etc.).

[0033] The first and second dielectrics may be disposed on either side of the high voltage electrode.

[0034] In some embodiments, the first and second ground electrodes separate the first and second reaction chambers by first and second dielectrics.

[0035] The first and second reaction chambers may each include an inlet for supplying oxygen gas or an oxygen-containing gas, and an outlet for releasing ozone gas.

[0036] The exterior surfaces of the first and second reaction chambers may be provided with cooling elements, such as cooling fins.

[0037] In some embodiments, air cooling may be used alone or in combination with water cooling to increase the efficiency of the ozone generation section.

[0038] In some other embodiments, only water cooling may be used to cool the ozone generation section.

[0039] The high voltage electrode may be disposed as a metallization of the first and / or second dielectric.

[0040] In some other embodiments, the high voltage electrode is a metal foil or sheet.

[0041] In some further embodiments, the first and second dielectric elements may contact the interior surfaces of the first and second reaction chambers.

[0042] The particular configuration described above has the advantage that heat generated during ozone generation can be more efficiently dissipated due to more efficient heat exchange between the cooled earth electrodes that are part of the first and second reaction chambers and the first and second dielectrics in contact with the inner surfaces of the first and second reaction chambers.

[0043] In a second aspect, the present invention relates to a method of operating an ozone generator according to the first aspect of the invention, the method comprising operating the ozone generator at a frequency of 25-40 kHz (such as 30-40 kHz).

[0044] In some embodiments, according to a second aspect of the present invention, operation of the ozone generator according to the first aspect of the present invention includes providing a flow of a fluid comprising oxygen gas to an ozone generating section, controlling the flow of the fluid comprising oxygen gas, and controlling the power provided from the power supply to the ozone generator at a frequency of 25-40 kHz (e.g., 30-40 kHz).

[0045] In a third aspect, the present invention relates to a method of operating an ozone generator, the method comprising operating the ozone generator at a frequency of 25-40 kHz, such as 30-40 kHz.

[0046] In some embodiments of the method of operating an ozone generator according to the third aspect of the present invention, operating the ozone generator includes providing a flow of a fluid comprising oxygen gas to the ozone generator, controlling the flow of the fluid comprising oxygen gas, and controlling power provided from a power supply to the ozone generator at a frequency between 25 and 40 kHz (e.g., 30 and 40 kHz).

[0047] In some further embodiments of the first, second or third aspects of the invention, the operating frequency is a frequency between 31 and 40 kHz (such as a frequency between 32 and 35 kHz).

[0048] In a fourth aspect, the present invention relates to a transformer assembly or transformer, such as a high power transformer configured or adapted to supply power in the frequency range of 25-40 kHz (such as 30-40 kHz).

[0049] The transformer assembly according to the fourth aspect may include a ferrite shell-type core surrounding the primary winding and the secondary winding.

[0050] The primary winding may have fewer than 14 turns and the secondary winding may have more than 107 turns. The ferrite shell-type core may have an air gap of less than 2.0 mm.

[0051] In some embodiments, the ferrite shell core comprises at least two portions separated from each other by an air gap of less than 2.0 mm.

[0052] The inventors have devised a high power transformer considering that the operating frequency of the ozone generator depends on the capacitance of the reactor and the inductance of the secondary side of the high voltage transformer. The inductance of the primary side of the high voltage transformer and the series inductance also have some effect on the operating frequency of the ozone generator.

[0053] To vary the operating frequency, the present invention uses a transformer assembly with increased inductance.

[0054] The inductance can be approximated by the following formula:

[0055]

number

[0056] μ0 is a physical constant and cannot be changed. The mechanical dimensions of the transformer assembly are constrained by the size of the ozone generating section. Furthermore, the ferrite core of the transformer assembly also has a predetermined dimension that cannot be changed.

[0057] In fact, according to the above formula,

[0058]

number

[0059] (geometric constant of the core) and A e (Core area) cannot be changed. e is a constant for the material used, modern ferrite.

[0060] The solution of the present invention is to change N (the number of turns in the primary winding) and G (the air gap of the core).

[0061] However, the constraints of the mechanical dimensions of the generator suggest that there is no room to increase the number of turns of the secondary winding without decreasing the number of turns of the primary winding of the transformer. The solution of the present invention was to modify the number of turns of the primary winding, for example by reducing it by a fixed number, such as by 1, 2, 3, 4 or 5 turns from a value currently used in transformer assemblies with an operating frequency of approximately 45 kHz, for example about 14 turns. This created enough space to modify the number of turns of the secondary winding, for example by increasing it by a fixed number, such as by 1, 2, 3, 4 or 5 turns from a value currently used in transformer assemblies with an operating frequency of approximately 45 kHz, for example about 107 turns.

[0062] Reducing the gap in a transformer increases the magnetic flux in the core. Reducing the frequency increases the magnetic flux, which leads to increased losses in the core. Reducing the frequency, on the other hand, reduces the number of flux direction changes, which in turn reduces losses. Thus, the gap was reduced by 0.25, 0.5, 0.75, 1, 1.1, and 1.2 mm from the values ​​currently used for transformer assemblies with operating frequencies of around 45 kHz, for example, about 2.1 to 2.2 mm.

[0063] Thus, in some embodiments, the present invention relates to a transformer assembly including a ferrite shell core surrounding a primary winding and a secondary winding, where the primary winding has fewer than 14 turns and the secondary winding has more than 107 turns, and where the ferrite shell core has an air gap of less than 2 mm.

[0064] By decreasing the gap, increasing the number of turns on the secondary winding, and decreasing the number of turns on the primary winding, the operating frequency was reduced from approximately 45 kHz to approximately 30 kHz.

[0065] This change may result in a slight increase in operating temperatures, although improved cooling solutions can help reduce the increase in operating temperatures.

[0066] Each of the first, second, third and other aspects and embodiments of the invention may be combined with any of the other aspects and embodiments. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief description of the drawings]

[0067] The ozone generator, its method of operation, and transformer assembly according to the present invention will now be described in more detail with reference to the accompanying drawings, which illustrate one way of practicing the invention and should not be construed as limiting to other possible embodiments within the scope of the appended claims.

[0068] [Figure 1] FIG. 1 shows a cross-section of an ozone generation section according to some embodiments of the present invention. [Diagram 2] FIG. 2 shows a cross section of an ozone generation section according to some other embodiments of the present invention. [Diagram 3] Figure 3 shows a graph of weighted audible noise versus operating frequency, showing the ratio of actual ozone production to setpoint production. [Figure 4] FIG. 4 is an exploded view of a transformer assembly according to some embodiments of the present invention. [Diagram 5] FIG. 5 is a perspective view of a transformer assembly according to some embodiments of the present invention. [Figure 6] FIG. 6 is a flow diagram of a method of operating an ozone generator according to some embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0069] FIG. 1 shows an ozone generating section 27 comprising a first PTFE sheet 23 and a second PTFE sheet 24 surrounding a high voltage electrode 16 .

[0070] First and second reaction chambers for producing ozone are defined on one side by first and second PTFE sheets 23 and 24, respectively, and by the inner surfaces of the housings or earth electrodes 14 and 15.

[0071] Oxygen gas enters ozone generation section 27 via inlets 19 and 20 and is exposed to corona discharge in the first and second reaction chambers, resulting in the formation of ozone gas, which is released from ozone outlets 21 and 22, respectively.

[0072] The housings or earth electrodes 14 and 15 are cooled by water flowing through water cooled chambers 11 and 13. The water cooled chambers 11 and 13 are defined by recesses on the outer surfaces of the earth electrodes 14 and 15 which are covered by covers 10 and 12.

[0073] Stainless steel nets or sheets 25 and 26 are disposed between the inner surfaces of the earth electrodes 14 and 15 and the first PTFE sheet 23 and the second PTFE sheet 24. The stainless steel nets or sheets 25 and 26 are corona effect promoting structures which promote electrical discharge between the electrodes.

[0074] Supporting PTFE rings 17 and 18 are positioned between the earth electrodes 14 and 15 .

[0075] The supporting PTFE ring may function as a spacer, ensuring that a reaction chamber is formed between the earth electrode and the high voltage electrode.

[0076] FIG. 2 shows an ozone generating section 45 comprising a first PTFE sheet 43 and a second PTFE sheet 44 surrounding the high voltage electrode 36 .

[0077] First and second reaction chambers for producing ozone are defined on one side by first and second PTFE sheets 43 and 44, respectively, and by the inner surfaces of the housings or earth electrodes 34 and 35.

[0078] Oxygen gas enters ozone generation section 45 via inlets 39 and 40 and is exposed to corona discharge in the first and second reaction chambers, resulting in the formation of ozone gas, which is released from ozone outlets 41 and 42, respectively.

[0079] The housings or earth electrodes 34 and 35 are cooled by water flowing through water cooled chambers 31 and 33. The water cooled chambers 31 and 33 are defined by recesses on the outer surfaces of the earth electrodes 34 and 35 which are covered by covers 30 and 32.

[0080] Supporting PTFE rings 37 and 38 are positioned between the earth electrodes 34 and 35 .

[0081] The ozone generating section 45 has first and second PTFE sheets 43 and 44 which are in contact with the inner surfaces of the first and second reaction chambers, i.e., the inner surfaces of the earth electrodes 34 and 35 .

[0082] This configuration allows for improved and efficient cooling of the PTFE sheet by contacting the inner surface of an externally water-cooled earth electrode.

[0083] Figure 3 shows a graph of weighted audible noise versus operating frequency, showing the ratio of actual ozone production to setpoint production.

[0084] The X-axis represents the operating frequency (Hz) of the ozone generator according to the first aspect of the present invention.

[0085] The Y1 axis is the weighted value of audible noise reduction (dBa).

[0086] Line 1 represents the aggregate data for ozone generators operated at various frequencies and noise reduction.

[0087] It can be seen that by increasing the frequency between 10kHz and 30kHz, the noise is significantly reduced, with a maximum reduction of -32.5dBa. By increasing the operating frequency further to 40kHz, the noise can be reduced by a maximum of -37.5dBa. Even if the operating frequency is increased beyond this, the audible noise generated by the ozone generator does not decrease significantly.

[0088] The Y2 axis is the ozone concentration of 200grO3 / Nm 3 , 2 bar, ozone release 100% capacity, the ratio of the actual ozone production to the set ozone production (Oa v / O sv ).

[0089] A value of 100 on the Y2 axis represents a state where the set value corresponds to the actual value. That is, a set value of 200 grO3 / Nm 3 In this case, the actual value of ozone released was 200grO3 / Nm 3 A value below 100 corresponds to a condition where the setpoint is higher than the actual ozone release, i.e. less ozone is released compared to the setpoint.

[0090] A value greater than 100 corresponds to a condition where the setpoint is lower than the actual ozone release, i.e. more ozone is released compared to the setpoint.

[0091] Line 2 shows the correspondence between the set value and the actual measured value depending on the operating frequency.

[0092] It can be seen that the higher the operating frequency, the worse the correspondence between the set value and the actual measured value of released ozone.

[0093] In fact, for example, at a high frequency of 60 kHz, the corresponding value of 90 corresponds to a set value of 200 grO3 / Nm 3 For 180grO3 / Nm 3 This means that only

[0094] Reducing the operating frequency improves the correspondence between the setpoint and measured ozone emissions.

[0095] For example, when the operating frequency is 30 kHz, the corresponding value 102 is set to 200 grO3 / Nm 3 204grO3 / Nm 3 This means that is released.

[0096] Within the acceptable range of deviation between the set value and the actual measured value, i.e. within 100+ / -2, it was surprisingly found that an operating frequency of 30~40kHz was the frequency that produced the least audible noise, i.e. the greatest reduction in dBa (i.e. -32.5dBa~-37.5dBa).

[0097] Therefore, the inventors configured the ozone generator to operate at a frequency of 30-40 kHz.

[0098] In FIG. 4, a transformer assembly 5 according to some embodiments of the present invention comprises a ferrite core having two portions 3 and 6 separated by a gap pad 7 and primary and secondary windings 4 and 8 .

[0099] FIG. 5 is a perspective view of the transformer assembly 5 shown in exploded view in FIG.

[0100] 6 is a flow diagram of a method of operating an ozone generator 9, an ozone generator according to a first aspect of the present invention. The method comprises operating the ozone generator at a frequency of 25-40 kHz (such as 30-40 kHz).

[0101] The operation of an ozone generator involves: S1, supplying a fluid stream containing oxygen gas to an ozone generator; S2, controlling the flow of a fluid containing oxygen gas; · S3, which includes controlling the power supplied from the power supply to the ozone generator at a frequency of 25-40 kHz (e.g., 30-40 kHz).

[0102] Although the present invention has been described with reference to certain embodiments, it should not be construed as being limited to the examples presented. The scope of the present invention is indicated by the appended set of claims. In the context of the claims, the term "comprising" or "comprises" does not exclude other possible elements or steps. Also, the recitation of references using "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims for elements shown in the drawings should not be construed as limiting the scope of the present invention. Moreover, individual features recited in different claims can possibly be combined advantageously, and the recitation of these features in different claims does not exclude that a combination of features is not possible or advantageous.

Claims

1. A high voltage electrode portion (16, 36); a first (23, 43) and a second (24, 44) dielectric element; an ozone generating unit (27, 45) having a first (14, 34) and a second (15, 35) earth electrode; the high voltage electrode portion is disposed between the first dielectric element and the second dielectric element; The ozone generating unit is configured to operate at an operating frequency range of 30 to 40 kHz; An ozone generator, comprising a transformer assembly, a low frequency, high voltage AC power supply configured to provide 50-800 watts at a frequency of 30-40 kHz to an ozone generating section.

2. 2. The ozone generator of claim 1, wherein the first and second dielectric elements are disposed at a distance within a range of 0.01 to 0.1 mm, for example 0.01 to 0.075 mm, from the high voltage electrode portion.

3. 3. An ozone generator as claimed in claim 1 or 2, wherein the first and second dielectric elements are spaced from the high voltage electrode portion by one or more spacer elements.

4. 4. The ozone generator according to claim 1, wherein the first and second dielectrics are disposed on either side of the high voltage electrode.

5. 5. The ozone generator according to claim 1, wherein the first and second earth electrodes divide the first and second reaction chambers by the first and second dielectrics.

6. An ozone generator according to any one of claims 1 to 5, wherein the high voltage electrodes are disposed as metal coatings on the first and second dielectrics.

7. The ozone generator according to any one of claims 1 to 5, wherein the high voltage electrode is a metal foil or a metal sheet.

8. The ozone generator according to any one of claims 5 to 7, wherein the first and second reaction chambers each comprise at least an inlet (19, 20, 39, 40) for supplying oxygen gas or an oxygen-containing gas and at least an outlet (21, 22, 41, 42) for releasing ozone gas.

9. An ozone generator according to any one of claims 5 to 8, wherein the outer surfaces of the first and second reaction chambers are provided with cooling elements, such as cooling fins.

10. 10. An ozone generator according to any one of claims 5 to 9, wherein the first and second dielectric elements are in contact with inner surfaces of the first and second reaction chambers.

11. An ozone generator according to any one of claims 1 to 10, wherein the transformer assembly is a high power transformer.

12. 12. The ozone generator of claim 1, wherein the transformer assembly is a high power transformer comprising a ferrite shell-type core surrounding a primary winding and a secondary winding, the primary winding having fewer than 14 turns and the secondary winding having more than 107 turns, and the ferrite shell-type core having an air gap of less than 2 mm.

13. A method for operating the ozone generator according to any one of claims 1 to 12, said method comprising the steps of: A method for operating an ozone generator, comprising operating the ozone generator at a frequency of 30 to 40 kHz.

14. The operation includes: providing a fluid stream comprising oxygen gas to the ozone generator; controlling a flow of the oxygen gas-containing fluid; and controlling the power supplied to the ozone generator from a power supply at a frequency of 30 to 40 kHz.

15. A method of operating an ozone generator according to any one of claims 13 to 15, wherein the frequency is between 31 and 40 kHz, such as between 32 and 35 kHz.

16. 1. A transformer assembly, such as a high power transformer, configured to provide power in a frequency range of 30-40 kHz, A ferrite shell-type core surrounding a primary winding and a secondary winding, 1. A transformer assembly, wherein the primary winding has fewer than 14 turns, the secondary winding has more than 107 turns, and the ferrite shell core has an air gap of less than 2 mm.

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