WO2006007639A1

WO2006007639A1 - An improved apparatus and method for cleaning using a combination of electrolysis and ultrasonics

Info

Publication number: WO2006007639A1
Application number: PCT/AU2005/001048
Authority: WO
Inventors: Wah-Tong Lee
Original assignee: Soniclean Pty Ltd
Priority date: 2004-07-16
Filing date: 2005-07-18
Publication date: 2006-01-26

Abstract

The present invention relates to a method and apparatus which combines the effects of electrolysis and ultrasonics. The apparatus (10) can be used to clean electrically conducting material and electrically non-conducting material. Electrolysis augments the use of an ultrasonic generator (18) by assisting in the removal of foreign matter from the surface of the article being cleaned. Furthermore, the process of electrolysis creates free radicals (60), such nascent oxygen, which is dispersed by the affects of an ultrasonic generator (18). Free radicals (60) are toxic to living organisms and therefore are able to destroy bacteria and other harmful organisms on the articles (34, 56, 62) being cleaned. The present invention therefore provides an improved cleaning apparatus and sterilising unit by combining the effects of electrolysis and ultrasonics.

Description

An improved apparatus and method for cleaning using a combination of electrolysis and ultrasonics

FIELD OF THE INVENTION

The present invention relates to an apparatus useful for cleaning a surface using the combined effects of electrolysis and ultrasonics. The surface cleaned by the apparatus and method of the invention may either be electrically conductive material, such as metal, or non-electrically conductive material, such as plastic or wood.

BACKGROUND OF THE INVENTION

Ultrasonic cleaning is used in numerous applications for sterilising and cleaning surfaces. Ultrasonic baths are widely used in the cleaning of small articles such as rings and other jewellery articles. These articles are often small and have complex surface geometries that make simpler washing processes less effective. For example, crevices may be inaccessible by a simple washing process. Also, jewellery items are often relatively delicate and are not suited to harsh physical cleaning treatments that may scratch or otherwise damage the surface. This applies to other metal surfaces to be cleaned. Ultrasonics are also used in cleaning the interior surface of wine barrels.

Ultrasonic cleaning is the introduction of high-frequency sound waves into a liquid, usually between 20 to 80 kHz. The resulting action is called "cavitation".

Cavitation is created by high and low pressure areas produced in the solution as the sound waves pass through it. In low-pressure areas, microscopic vapour bubbles form. The pressure rises rapidly as the next sound wave pass through the area, violently imploding the minute bubbles and relating the energy that does the cleaning. At 20 kHz, this is happening 20,000 times per second. The resulting cleaning action is very effective on those parts of the article that are directly in the line of sight of the sound wave although less so on those parts of the article that are less exposed to the ultrasonic action.

An alternative method of cleaning is the use of electrolysis. During typical operation of an electrolysis cell, an electric current is produced and hydrogen and oxygen are produced at the negative (cathode) and positive (anode) electrodes, respectively, which typically are metal plates positioned in a selected electrolyte. The hydrogen and oxygen thus produced may be captured and used as desired, or may be discarded, depending on the particular application.

Many different electrolysis systems are known, but typically, a pulsating DC voltage is generated and applied to the electrodes. The signal has particular characteristics with values selected such that hydrogen is produced at the cathodic portion of the electrode. The article to be cleaned is attached to and forms a part of the cathode and whilst the current is maintained rapidly acquires a coating of small hydrogen bubbles. The article at the cathode undergoes a process of cathodic reduction and any detritus or oxide material on the surface of the metal is rapidly reduced to the point where it is readily removed from the article.

The present invention is directed to a method and apparatus that is able to combine the effects of these two techniques.

SUMMARY OF THE INVENTION

Therefore, in one form of the invention there is provided an apparatus adapted for the treatment of an article in contact with an electrolyte, by the combined application of electrolytic and ultrasonic energy, including: at least one cathode; at least one anode, wherein a current flows through said electrolyte between said anode and said cathode; at least one ultrasonic generator adapted to emit an ultrasonic signal within said electrolyte; wherein said electrolytic and ultrasonic energy is controllably applied to said article.

Preferably, the activity of said ultrasonic generator and said cathode and anode are controlled independently.

Preferably, said article is electrically conductive.

" Preferably, said article is electrically non-conductive.

Preferably, said electrically non-conductive article is suspended within said electrolyte. Preferably, said apparatus is used to clean a wine barrel having a restricted opening.

Preferably, said apparatus includes a first and a second probe adapted to fit through said restricted opening.

Preferably, said first probe is configured to act as an ultrasonic generator and a +ve electrode, said second probe is configured to act as an ultrasonic generator and a -ve electrode.

Preferably, said electrolyte is water.

In a further form of the there is provided an apparatus adapted for cleaning conductive articles by the combined application of electrolytic and ultrasonic energy wherein said apparatus includes: a cleaning vessel having associated therewith means for supporting an article to be cleaned and means for the supply of pulsed electrical power to the article to be cleaned to thereby effect an electrolytic cleaning process; and an ultrasonic generator to thereby effect an ultrasonic cleaning process for the supply, wherein the electrolytic cleaning process and the ultrasonic cleaning process are controlled independently.

Preferably, the means for the supply of pulsed electrical power includes a conductor cable extending around a periphery of the vessel, the conductor being attachable to a connector to which a work support is attached, said work support, in turn, being attachable to said article to be cleaned.

Preferably, said connector includes a pin receivable in a socket in said vessel said socket being electrically connected to said conductor.

Preferably, the apparatus includes a safety shut off mechanism designed to detect a short circuit condition.

Preferably, said conductive article is connected to the cathode.

In yet a further form of the invention there is provided a method for treating an article including the steps of: placing said article in an electrolyte; applying electrolytic energy to said electrolyte; applying ultrasonic energy to said electrolyte; wherein the production of said electrolytic and ultrasonic energies are controlled to thereby treat said article.

Preferably, the production of said electrolytic and ultrasonic energies is controlled independently.

DESCRIPTION OF DRAWINGS

The above and other objects, features, and advantages of the present invention will be apparent from the following detailed description of a preferred embodiment in conjunction with the accompanying drawings. In the drawings:

Figure 1 illustrates a cleaning apparatus in accordance with a first embodiment of the present invention;

Figure 2 illustrates in cross sectional view a detail of the apparatus of Figure 1 in a first position;

Figure 3 illustrates in cross-sectional view a detail of the apparatus of Figure 1 in a second position;

Figure 4a, 4b & 4c illustrate schematically how the apparatus of the invention operates;

Figures 5 illustrates schematically an apparatus in accordance with a second embodiment of the invention;

Figure 6 illustrates in cross-sectional view an apparatus in accordance with a third embodiment of the invention;

Figure 7 illustrates in cross-sectional view an apparatus in accordance with a fourth embodiment of the invention; and

Figure 8 illustrates in cross-sectional view the apparatus of Figure 7 including a shield.

DESCRIPTION OF THE PREFERRED EMBODIMENT The following detailed description of the invention refers to the accompanying drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts.

Shown in Figure 1 is an apparatus 10 constructed in accordance with the present invention. The apparatus 10 is thus adapted to perform both an electrolytic cleaning function and an ultrasonic cleaning function. The apparatus 10 includes a bath 12 having a work supporting bar 14 suspended over the bath 12, electrical connectors 16 attached to the bar 14. Not shown in the drawings are a source of direct current electrical power and an ultrasonic generator 18.

The bath 12 is generally rectangular, although it will be appreciated that any shape of bath could be used and that the dimensions of the bath are more dependent on the geometry of the article to be cleaned than on any specific physical requirements. The bath 12 is a double skinned bath and thus has an interior volume 20 than can conveniently house the ultrasonic generator 18 and other functional parts. Importantly around an upper periphery of the bath and within the cavity 20 is an electrical conductor 22. The conductor 22 is connected to the DC power supply.

In the embodiment under consideration the work supporting bar 14 extends diagonally across the bath 12. At each end the work supporting bar 14 is attached to a respective electrical connector 16. A shown in Figures 2 and 3 the electrical connectors 16 are in electrical contact with the conductor 22 and thus the DC power supply.

The electrical connectors 16 each consist of a pin element 24 that extends through and forms an electrical contact with the work supporting bar 14. The pin elements 24 have a generally vertically arranged split 26 therein and an upmost insulating sheath 27.

The pin elements 24 are each received in a respective connector 28. The connector 28 incudes an outermost electrically insulated nut 30 and an axial conductive tube 32. The conductor 22 is attached to a lower end of the tube 32.

The pin 24 is received in the tube 32 and by splaying the pin about the split 26 a secure electrical contact to the tube 32 and thus to the conductor 22 is assured. The drawings in Figures 2 and 3 illustrate how easily the work supporting bar 14 can be disconnected from the conductor 22 simply by grasping the sheath 27 and lifting the pin 24 out of the connector 28.

Articles to be cleaned, for example, rings 34, are suspended by a conductive wire from the work supporting bar 14.

In use, the apparatus 10 is provided with a control unit (not shown) that controls the operation of the unit and permits all of the functions of the unit to be controlled independently. The controller allows:

• Programmable power levels and duty cycles for electrolysis. • Programmable power patterns (powers and duty cycle) for ultrasonic cleaning.

• Programmable degassing process.

• Programmable cut-out temperature for tank temperature.

• Digital display and audible beeper to show the current operational status of the cleaner. • Operator alerted power failure during a cleaning or degas process detection.

• Operator alerted electrolysis overload detection

• Operator alerted over temperature detection and

• Internal cooling control of electronics.

The apparatus 10 can thus operate independently as an ultrasonic cleaning unit, an electrolytic cleaning unit or in combination.

Electrolytic cleaning is achieved by applying a pulsating DC current to the unit. Typically, the device is wired such that the article to be cleaned is the cathode and the bath 12 is wired as the anode. Hence, during electrolysis hydrogen generated will accumulate around the article. A simplified illustration of this process is shown in Figures 4a, 4b and 4c. The article 34 has attached thereto dirt or metal oxide or other material to be removed 36. The bubbles 38 generated in the electrolytic cleaning process are generated around all of the surfaces of the article 34 and, importantly, at the surface of the article, that is, between the article and the surface contaminant. The bubbles 38 therefore serve to partially dislodge the contaminant 36 from the article 34 as illustrated in Figure 4b. The cleaning process is completed by the application of ultrasonics. The ultrasonic process further dislodges the dirt or surface contamination 36, as a result of mechanical interference, further lifting it completely from the surface of the article. It also aids in the dispersion of the bubbles 38 so that the article 34 is not insulated against further electrolysis.

Not illustrated but also included in the control module is a short circuit safety device. In the event that two or more of the items in the bath 12 touch one another thereby causing a short circuit the safety device will operate to cut off power.

Typically the electrolytic cleaning will be carried out in duty cycles, based on 60 seconds cycle for the user. For example, electrolysis may occur in from 20 seconds in a 60 second cycle to a max 60 seconds in a 60 second cycle. The duty cycle rate may be varied between three ranges in a stepped fashion. It is, of course, important to note that these ranges are selected arbitrarily and that any given article to be cleaned and indeed any cleaning apparatus may have entirely different duty cycles.

Similarly, the power level during electrolytic cleaning may be increased in fractions from 2/10 to max 10/10 (amps or amperage) in 5 simplified increments. Each power level is divided into 5 millisecond increments. It is possible to step through and select any duty cycle and power levels and combine these two configurations.

With "ultrasonic power patterns" one can select power levels 1 , 2 or 3 and duty cycle 25%, 50% or 75%, and then combine the electrolytic and ultrasonic cycles.

Separate electrolysis power patterns and ultrasonic power patterns may be operated or it is possible to combine these two configured process simultaneously.

Aside from the use of electrolysis power pattern a preset power of Watts could be used to allow the patterns for electrolysis and ultrasonic to be configured. The use of constant fixed voltage will reach a limitation of maximum optimum power, given a constant conductivity of cleaning fluid, temperature and electrodes (-ve electrode substrates of parts and the +ve electrode the tank). To extend this power limitation (given the rest of the variable being the same) one can step into higher voltages eg up to say 24 Volts (using Ohms Law). This requires a feedback control to be installed onto the circuit to provide the necessary control to give the nominated power output.

Below are the methodologies for electrolysis and ultrasonic configurations each separately or both simultaneously:

1. Monitor the electrolysis current to switch to the correct electrolysis power pattern or the ultrasonic power pattern. 2. Switch both on simultaneously self-configuring optimum electrolysis power patterns and ultrasonic power pattern

3. Switch on/off self-configuring alternating between electrolysis power patterns and ultrasonic power pattern

The above 3 possible process can be dependent on fluid conductivity, fluid temperature and conductivity of the part substrate. These three variables will change during the clean cycle.

An alternative form of the invention is illustrated in Figure 5. This illustrates the usefulness of the conductor 22. In this case a multiple of work support bars 14 are each connected through two respective connectors 16 configured as previously described. The unit thus has a great degree of flexibility as to the size and disposition of articles placed with the bath.

In yet a further alternate embodiment as illustrated in Figure 6 the apparatus 10 can be in the form of a bath 12 for use in relation to cleaning non-conductive surfaces. The bath 12 includes a conductive insert 40 and an outer non-conductive housing 42 as is well known in the art. A clamp 44 which is connected to a power source (not shown) by way of cable 46 is connected to conductive insert 40. In the present embodiment the conductive insert 40 acts as the anode for electrolysis. A probe 48 which is connected to a power source (not shown) by way of cable 50 is suspended in the bath 12 which contains electrolyte 52. Probe 48 is configured to act as a cathode. The non-conducting articles 54 which are being cleaned are placed within tray 56 which is suspended within electrolyte 52. An ultrasonic generator 18 which is connected to a power source (not shown) by cable 58 is also placed within the bath 12.

The process of electrolysis which results in a flow of ions between the cathode 49 and anode 40 results in the production of free radicals 60. Free radicals 60, such nascent oxygen, are toxic to living organisms and consequently bacteria and other harmful organisms which are in contact with electrolyte 52 are eradicated. In addition, to assist the formation of free radicals 60, chemicals such as chlorine (Cl) and hydrogen peroxide (H₂O₂) may be added if suitable.

To assist in the cleaning and disinfection of electrically non-conductive porous material, metallic particles that are known to be harmful to bacteria, such as silver, can be added to the electrolyte 52. These metallic particles are dispersed by the action of the ultrasonic generator 18 and assist in disinfecting the surface being cleaned. This would be particularly useful on articles used in the medical field or in food storage and preparation.

The apparatus 10 can be further used for cleaning containers such as wine barrels 62. As illustrated in Figure 7, wine barrels 62 typically include wooden staves 64, metal bands 66 and bung holes 68. The interior surfaces of wine barrels 62 are electrically non-conductive. Consequently, both an anode and a cathode must be inserted into the electrolyte 52 to undertake electrolysis. As illustrated in Figure 7, probes 70 and 72 are inserted through bung hole 68. Probe 70 is connected to a power source by cable 46 and is configured to act as the anode for electrolysis. The probe 72 is connected to a power source by cable 50 and is configured to act as the cathode. In this manner, free radicals 60, which are toxic to living organisms, are able to be formed within the electrolyte 52. Because ions will typically find the shortest or least resistive path between the anode and cathode the probes 70 and 72 include insulation 74 which prevents the flow of ions in close proximity to the bung hole 68 where the distance between the probes 70 and 72 is the least. The probes 70 and 72 are also adapted to act as ultrasonic generator and are connected to ultrasonic generators (not shown) by cables 56. As the reader would now appreciate, the probes 70 and 72 are configured to both produce free radicals 60 and disperse them throughout the wine barrel 62. The apparatus, as illustrated in Figure 8, further includes a shield 76 adapted to restrict the current flow and movement of free radicals 60 within the cleaning fluid 52. The ions will find the shortest or least restrictive path between the anode probe 70 and the cathode probe 72 and consequently the shield 76 ensures that the flow indicated by arrows 78 is diverted from a direct path to ensure the barrel 62 is sufficiently cleaned.

It is well known that the more material that is suspended in the electrolyte 52 the more conductive the fluid will become. Therefore as the reader would appreciate, the longer the cleaning is undertaken the more effective the electrolysis will be. Consequently, as the electrolyte 52 becomes more saturated with suspended material and the effectiveness of the ultrasonic generator 18 is reduced, the efficiency of the electrolytic cleaning function increases.

Chemicals may also be added to improve conductivity of the electrolyte 52, for instance, salt, sugar or detergent could be added to increase the efficiency of the electrolysis. This would be particularly useful when cleaning articles such as containers used for transporting organs.

In effect, where the item being cleaned is electrically conductive, electrolysis strips material and creates free radicals 60, whilst the ultrasonic generator 18 acts to clean and disperse the free radicals 60 within the bath 12. In the situation where the article being cleaned is electrically non- conductive, electrolysis creates free radicals 60 which are dispersed by the action of the ultrasonic generator 18. The ultrasonic generator 18 further acts to clean the electrically non-conductive article. As the reader would appreciate the dual action of electrolysis and ultrasonics produces a more efficient cleaning apparatus.

The reader would appreciate that the present invention has many applications for cleaning electrically conducting and electrically non¬ conducting material. The invention could also be used to sterilise bodies of fluid such as wine or water in fish ponds. The present invention has many advantages over the prior art by combining the effects of electrolysis and ultrasonics. The combination of these two processes enhances each individual method, for instance, the free radicals 60 produced by electrolysis are dispersed by the action of ultrasonic generator 18. Consequently, the present invention increases the effectiveness of the individual techniques. Furthermore, where the water includes large quantities of particles in suspension and hence the effectiveness of the ultrasonic activity may be reduced, electrolysis will be more efficient.

Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

In any claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

Claims

1. An apparatus adapted for the treatment of an article in contact with an electrolyte, by the combined application of electrolytic and ultrasonic energy, including: at least one cathode; at least one anode, wherein a current flows through said electrolyte between said anode and said cathode; at least one ultrasonic generator adapted to emit an ultrasonic signal within said electrolyte; wherein said electrolytic and ultrasonic energy is controllably applied to said article.

2. An apparatus as in claim 1 wherein the activity of said ultrasonic generator and said cathode and anode are controlled independently.

3. An apparatus as in any one of the above claims wherein said article is electrically conductive.

4. An apparatus as in claim 3 wherein said electrically conductive article is attached to said cathode.

5. An apparatus as in any one of the above claims wherein said article is electrically non-conductive.

6. An apparatus as in claim 5 wherein said electrically non-conductive article is suspended within said electrolyte.

7. An apparatus as in claim 1 wherein said apparatus is used to clean a wine barrel having a restricted opening.

8. An apparatus as in claim 7 wherein said apparatus includes a first and a second probe adapted to fit through said restricted opening.

9. An apparatus as in claim 8 wherein said first probe is configured to act as an ultrasonic generator and a +ve electrode, said second probe is configured to act as an ultrasonic generator and a -ve electrode.

10. An apparatus as in any one of the above claims wherein said electrolyte is water.

11. An apparatus adapted for cleaning conductive articles by the combined application of electrolytic and ultrasonic energy wherein said apparatus includes: a cleaning vessel having associated therewith means for supporting an article to be cleaned and means for the supply of pulsed electrical power to the article to be cleaned to thereby effect an electrolytic cleaning process; and an ultrasonic generator to thereby effect an ultrasonic cleaning process for the supply, wherein the electrolytic cleaning process and the ultrasonic cleaning process are controlled independently.

12. An apparatus as in claim 11 wherein the means for the supply of pulsed electrical power includes a conductor cable extending around a periphery of the vessel, the conductor being attachable to a connector to which a work support is attached, said work support, in turn, being attachable to said article to be cleaned.

13. An apparatus as in claim 12 wherein said connector includes a pin receivable in a socket in said vessel said socket being electrically connected to said conductor.

14. An apparatus as in claims 11 to 13 wherein the apparatus includes a safety shut off mechanism designed to detect a short circuit condition.

15. A method for treating an article including the steps of: placing said article in an electrolyte; applying electrolytic energy to said electrolyte; applying ultrasonic energy to said electrolyte; wherein the production of said electrolytic and ultrasonic energies are controlled to thereby treat said article.

16. An apparatus as in claims 11 to 13 wherein the production of said electrolytic and ultrasonic energies is controlled independently.