A LOW FREQUENCY OZONE GENERATOR

Abstract

The present invention relates to a method of operating an ozone generator, a transformer assembly and an ozone generator apparatus configured to be operated at an operational frequency range between 25-40 kHz, such as between 30 and 40 kHz.

Claims

1. An ozone generator apparatus comprising: an ozone generator unit comprising: a high voltage electrode unit; a first and second dielectric element; a first and second earth electrode; wherein said high voltage electrode unit is located between said first and said second dielectric element; and wherein said 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.

2-17. (canceled)

18. The ozone generator apparatus according to claim 1, wherein said first and second dielectric element are located at a distance from said high voltage electrode unit within a range between 0.01 and 0.1 millimeters.

19. The ozone generator apparatus according to claim 1, wherein said first and second dielectric element are spaced a part from said high voltage electrode unit by one or more spacer elements.

20. The ozone generator apparatus according to claim 1, wherein said first and second dielectric are arranged on both sides of said high voltage electrode.

21. The ozone generator apparatus according to claim 1, wherein said first and second earth electrode delimit a first and a second reaction chamber with said first and second dielectric.

22. The ozone generator apparatus according to claim 1, wherein said high voltage electrode is a metallic coating on said first and said second dielectric.

23. The ozone generator apparatus according to claim 1, wherein said high voltage electrode is a metal foil or a metal sheet.

24. The ozone generator apparatus according to claim 1, wherein said first and second reaction chamber comprise each at least an inlet configured to supply oxygen or an oxygen containing gas and at least an outlet for releasing ozone.

25. The ozone generator apparatus according to claim 1, wherein an external surface of said first and second chamber comprises a cooling element.

26. The ozone generator apparatus according to claim 1, wherein said first and second dielectric element are in contact with an internal surface of said first and second reaction chamber.

27. The ozone generator apparatus according to claim 1, wherein said transformer assembly is a high power transformer.

28. The ozone generator apparatus according to claim 1, wherein said transformer assembly is a high power transformer comprising a ferrite shell type core surrounding a primary winding and a secondary winding, wherein said primary windings has a number of turns lower than 14 and said secondary winding has a number of turns higher than 107 and said ferrite shell type core has an airgap smaller than 2 mm.

29. A method of operating an ozone generator apparatus according to claim 1, said method comprising: operating the ozone generator apparatus of claim 1 at a frequency between and 40 kHz.

30. A method of operating an ozone generator apparatus according to claim 29, wherein said operating comprises: supplying a flow of fluid containing oxygen to said ozone generator apparatus; controlling said flow of fluid containing oxygen; and controlling power supplied from a power supply apparatus to said ozone generator at a frequency between 30 and 40 kHz.

31. A method of operating the ozone generator apparatus according to claim 29, wherein said frequency is a frequency between 31 and 40 kHz.

32. A transformer assembly, being a high power transformer configured to provide electrical power within a frequency range between 30 and 40 kHz said transformer assembly comprising a ferrite shell type core surrounding a primary winding and a secondary winding, wherein said primary windings has a number of turns lower than 14 and said secondary winding has a number of turns higher than 107 and said ferrite shell type core has an airgap smaller than 2 mm.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0062] The ozone generator, the method of operating the ozone generator and the transformer assembly according to the invention will now be described in more details with regard to the accompanying figures. The figures show one way of implementing the present invention and are not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

[0063] FIG. 1 shows a cross section of an ozone generator unit according to some embodiments of the invention.

[0064] FIG. 2 shows a cross section of an ozone generator unit according to some other embodiments of the invention.

[0065] FIG. 3 shows a graph of operational frequency versus weighting audible noise and the ratio between the set value and the actual value of ozone production.

[0066] FIG. 4 is an exploded view of the transformer assembly according to some embodiments of the invention.

[0067] FIG. 5 is a perspective view of the transformer assembly according to some embodiments of the invention.

[0068] FIG. 6 is a flow-chart of a method of operating an ozone generator according to some embodiments of the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

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

[0070] The first and a second reaction chamber, in which ozone is generated, are delimited by the first PTFE sheet 23 and second PTFE sheet 24 on one side and the internal surface of the housing or earth electrodes 14 and 15, respectively. Oxygen gas enters the ozone generator unit 27 via inlets 19 and 20, is exposed to corona discharge in first and second reaction chambers leading to the formation of ozone gas that is released through ozone outlets 21 and 22, respectively.

[0071] The housing or earth electrodes 14 and 15 are cooled through water cooling flowing in the water cooling chambers 11 and 13. The water cooling chambers 11 and 13 are defined by recesses on the external surface of the earth electrodes 14 and 15 covered by covers 10 and 12.

[0072] Stainless steel nets or sheet 25 and 26 are located between the internal surface of the earth electrodes 14 and 15 and the first PTFE sheet 23 and second PTFE sheet 24. Stainless steel nets or sheet 25 and 26 are corona-effect promoting structures promoting discharge between the electrodes.

[0073] Support PTFE rings 17 and 18 are arrange between earth electrodes 14 and 15.

[0074] Support PTFE rings may have the function of spacers, ensuring the formation of reaction chambers between the earth electrodes and the high voltage electrode.

[0075] FIG. 2 shows an ozone generator unit 45 comprising a first PTFE sheet 43 and second PTFE sheet 44 surrounding a high voltage electrode 36.

[0076] The first and a second reaction chamber, in which ozone is generated, are delimited by the first PTFE sheet 43 and second PTFE sheet 44 on one side and the internal surface of the housing or earth electrodes 34 and 35, respectively.

[0077] Oxygen gas enters the ozone generator unit 45 via inlets 39 and 40, is exposed to corona discharge in first and second reaction chambers leading to the formation of ozone gas that is released through ozone outlets 41 and 42, respectively. The housing or earth electrodes 34 and 35 are cooled through water cooling flowing in the water cooling chambers 31 and 33. The water cooling chambers 31 and 33 are defined by recesses on the external surface of the earth electrodes 34 and 35 covered by covers 30 and 32.

[0078] Support PTFE rings 37 and 38 are arrange between earth electrodes 34 and 35.

[0079] The ozone generator unit 45 has the first and second PTFE sheet 43 and 44 in contact with an internal surface of the first and second reaction chamber, i.e. with the internal surface of the earth electrodes 34 and 35.

[0080] This configuration allows for an improved and efficient cooling of the PTFE sheets as being in contact with the internal surface of the earth electrodes that is externally water cooled.

[0081] FIG. 3 shows a graph of operational frequency versus weighting audible noise and a ratio between an actual value and a set value of production of ozone production.

[0082] The X axis represents the operational frequency, in Hz, of an ozone generator according to the first aspect of the invention.

[0083] The Y.sub.1 axis is a weighting value of the reduction of audible noise in dBa.

[0084] The line 1 represents a collection of data of ozone generators operated at different frequency versus noise reduction.

[0085] It can be noticed that the increase of frequency between 10 kHz and 30 kHz produces a substantial reduction of noise, i.e. up to −32.5 dBa. A further increase to 40 kHz provides a further reduction up to −37.5 Dba. An additional increase in operational frequency does not substantially reduce the noise audible by humans, which is produced by the ozone generator.

[0086] The Y.sub.2 axis is the ratio between an actual value of ozone production and a set value of ozone production O.sub.av/O.sub.sv at a 200 gr O.sub.3/Nm.sup.3 ozone concentration, at 2 bars, 100% capacity of ozone release.

[0087] The value 100 on the axis Y.sub.2 represents the condition when the set value corresponds to the actual value, thus for a set value of 200 gr O.sub.3/Nm.sup.3, the actual value of ozone released is 200 gr O.sub.3/Nm.sup.3. Values lower than 100 correspond to conditions in which the set value is higher than the actual ozone release, i.e. less ozone is released compared to the set value.

[0088] Values higher than 100 correspond to conditions in which the set value is lower than the actual ozone release, i.e. more ozone is released compared to the set value.

[0089] Line 2 shows the correspondence between the set values and actual values depending on the operational frequency.

[0090] It can be noticed that the higher the operational frequency, the worse the correspondence between the set value and the actual value of ozone released.

[0091] Indeed at high frequency, e.g. at 60 kHz, the correspondent value of 90 means that for a set value of 200 gr O.sub.3/Nm.sup.3 only 180 gr O.sub.3/Nm.sup.3 are released.

[0092] Reducing the operational frequency improves the correspondence between the set value and actual value of ozone released.

[0093] For example, for an operational frequency of 30 kHz, the correspondent value of 102 means that for a set value of 200 gr O.sub.3/Nm.sup.3, 204 gr O.sub.3/Nm.sup.3 are released.

[0094] Within the acceptable limits of deviation between set and actual value, i.e. 100+/−2, the operational frequency between 30 and 40 kHz was surprisingly found as the frequency providing the lowest audible noise, i.e. the highest reduction in dBa, i.e. between −32.5 Dba and −37.5 Dba.

[0095] The inventors thus configured the ozone generator so as to be operated with a frequency between 30 and 40 kHz.

[0096] In FIG. 4, the transformer assembly 5 according to some embodiments of the invention comprises a ferrite core having two parts 3 and 6 separated by a gap pad 7 and a primary and secondary windings 4 and 8.

[0097] FIG. 5 is a perspective view of the transformer assembly 5 showed in an exploded view in FIG. 4.

[0098] FIG. 6 is a flow-chart of a method of operating an ozone generator 9, the ozone generator apparatus according to the first aspect of the invention the method comprising operating the ozone generator apparatus at a frequency between 25-40 KHz, such as between 30 and 40 kHz.

[0099] The operating of the ozone generator comprises: [0100] S1, supplying a flow of fluid containing oxygen gas to the ozone generator; [0101] S2, controlling the flow of fluid containing oxygen gas; [0102] S3, controlling a power supplied from a power supply apparatus to the ozone generator at a frequency between 25-40 kHz, such as between 30 and 40 kHz.

[0103] Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms “comprising” or “comprises” do not exclude other possible elements or steps. Also, the mentioning of references such as “a” or “an” etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.