Electrochemical Treatment Equipment

Abstract

The present disclosure relates to a device comprising a device casing and first and second flexible contacts extending from the casing, each comprising a mounting means and a flexible applicator portion extending from the mounting means, the first and second flexible contacts each adapted to receive a conductive fluid and subsequently apply the conductive fluid to a surface, and one of the first and second flexible contacts being relatively positively charged and the other being relatively negatively charged.

Description

[Technical field]

[0001] The present invention relates generally to the field of treating conductive surfaces, and more particularly to the field of devices for electrochemically treating conductive surfaces. [Background technology]

[0002] Electrochemical reactions are used for a variety of processes on metal surfaces, such as cleaning a weld tint after assembly, electropolishing a surface, depositing or plating a material on a surface, or electrochemically etching a stencil design on a surface. This process requires that an electrical circuit be completed in the presence of a conductive fluid, which means that the conductive surface must be electrically connected to both opposing terminals of a power source. These connections are typically made by using a pair of opposing electrodes, which for convenience are referred to below as the "working" and "return" electrodes to indicate that the electrodes are connected to opposing power source terminals. Electrochemical processes require that the working electrode be positively or negatively charged relative to the conductive surface and the return electrode. The particular charge of the working electrode depends on the conductive surface, the desired electrochemical process, and the nature of the conductive fluid.

[0003] It is well known that when a conductive fluid is present at both the working and return electrodes, opposing electrochemical reactions, one desirable and the other potentially undesirable, will occur in the vicinity of both electrodes. However, if only one of these electrochemical reactions is desired to occur, then only the working electrode should conduct electricity through the conductive fluid, and the return electrode must be a "direct return electrode," in that it is directly connected to a conductive surface.

[0004] A typical prior art electrochemical cleaning / etching / marking tool includes a contact tool that functions as a working electrode (sometimes called a "wand") and conductive fluid applicator, and a ground clamp that is fixed directly on the conductive surface to provide a direct return electrode. The contact tool and ground clamp are connected to opposing terminals of a power source. As long as the ground clamp is connected, contacting the contact tool with a conductive fluid to a conductive surface can complete a circuit and induce a desired electrochemical reaction.

[0005] Some alternative prior art configurations may utilize a direct return electrode that relies on pressure from the user and a spring to maintain a return connection to the workpiece, while other configurations may rely on a conductive workbench to act as a direct return electrode and maintain an electrical connection with the workpiece.

[0006] Those skilled in the art will appreciate that applying or "plating" a material onto a conductive surface generally requires that the working electrode be positive with respect to the conductive surface, while removing material (e.g., as occurs during a cleaning or polishing process) generally requires that the working electrode be negative with respect to the conductive surface. However, those skilled in the art will appreciate that the electrochemical principles are the same regardless of what effect the user is seeking: an electrical circuit must still be established and a conductive fluid must still be applied.

[0007] Prior art electrochemical cleaning / etching / marking tools vary in working electrode size, shape, and configuration, and may have various advantages or disadvantages. However, each electrochemical cleaning / etching / marking tool requires the presence of a ground clamp or other form of direct return electrode. Unfortunately, the various prior art direct return electrode designs each represent significant limitations imposed on the user. For example, the use of a ground clamp limits the user's mobility; i.e., the ground clamp is tethered to the electrochemical cleaning / etching tool's power source via a cable, and to move beyond the reach of said cable, the user must remove the ground clamp and reinstall it in a new location. Furthermore, not all surfaces provide an easily accessible protrusion onto which a ground clamp can be properly attached to function; for example, a large, smooth metal surface, such as the inside of a silo or water tank, may not have a suitable protrusion to accept a ground clamp. Similarly, a spring-pressure direct return electrode requires constant attention from the user to maintain the required pressure. Finally, prior art electrochemical cleaning / etching / marking tools that rely on a conductive workbench can only work on projects where they are placed directly on the workbench, limiting the user in that such prior art tools are essentially completely immobile.

[0008] There is therefore a need to provide an electrochemical cleaning / etching apparatus that offers improvements in its mobility and / or portability or that at least overcomes some of the shortcomings of the prior art. In particular, it is an object of the present invention to provide an electrochemical cleaning / etching apparatus that does not require a separate ground clamp or other form of separate direct return electrode that tethers or otherwise restricts the user to a particular area. Summary of the Invention

[0009] In a first aspect, the present disclosure relates to a device comprising a device casing and first and second flexible contacts extending from the casing, each comprising an attachment means and a flexible applicator portion extending from the attachment means, the first and second flexible contacts each adapted to receive a conductive fluid and subsequently apply the conductive fluid to a surface, and one of the first and second flexible contacts being relatively positively charged and the other being relatively negatively charged.

[0010] In one embodiment, the power received by the first and second flexible contacts from the power source may be alternating current (AC) power such that the first flexible contact alternates between being positively and negatively charged and the second flexible contact alternates between being negatively and positively charged, the alternation of each of the first and second flexible contacts occurring simultaneously and in opposite directions.

[0011] In one embodiment, the power source may be an alternating current (AC) power source.

[0012] In an alternative embodiment, the power source may be a direct current (DC) power source, and the apparatus may further comprise a switch unit between the power source and the first and second flexible contacts, the switch unit electrically connected to the voltage output terminal, the ground terminal, and the first and second flexible contacts, and a switch controller connected to the switch unit and having a charging polarity period, the switch unit having a first configuration in which the first flexible contact is relatively positively charged and the second flexible contact is negatively charged, and a second configuration in which the first flexible contact is relatively negatively charged and the second flexible contact is positively charged, and the switch controller configured to periodically toggle the switch unit between the first configuration and the second configuration at a rate determined by the toggle period.

[0013] In one embodiment, the apparatus may further comprise a DC-DC converter electrically connected to the power source and the switch unit, the voltage output terminal and the ground terminal being respective terminals of the DC-DC converter, and the DC-DC converter is configured to receive a constant voltage input from the power source, convert the constant voltage input to a pulsed voltage output, and provide the pulsed voltage output to the switch unit via the voltage output terminal, and further, the pulsed voltage output includes a voltage waveform having a repeating pattern formed by alternating maximum and minimum voltages and having a pulse period, and the charging polarity period is substantially equal to an integer multiple of the pulse period. In one embodiment, the charging polarity period may be substantially equal to an odd multiple of the pulse period.

[0014] In one embodiment, the pulsed voltage output may include a voltage waveform having an asymptotic slope at its minimum voltage and a non-asymptotic slope elsewhere, and the timing at which the switch controller toggles the switch unit is substantially coincident with the minimum voltage. In one embodiment, the voltage waveform may be a rectified full wave sinusoidal waveform.

[0015] In one embodiment, the switch unit may comprise an array of switches, the array comprising a first switch forming a closeable circuit segment between the voltage output terminal and the first flexible contact, a second switch forming a closeable circuit segment between the voltage output terminal and the second flexible contact, a third switch forming a closeable circuit segment between the ground terminal and the first flexible contact, and a fourth switch forming a closeable circuit segment between the ground terminal and the second flexible contact, further wherein toggling the switch unit to the first configuration includes closing the first and fourth switches and opening the second and third switches, and toggling the switch unit to the second configuration includes opening the first and fourth switches and closing the second and third switches.

[0016] In an alternative embodiment, the power source is a direct current (DC) power source and the first flexible contact may comprise a contact area substantially smaller than a contact area of ​​the second flexible contact, hi one embodiment, the contact area of ​​the first flexible contact may be at least two times smaller than the contact area of ​​the second flexible contact.

[0017] In one embodiment, the DC power source may be a battery, a power cell, a fuel cell, or other stand-alone DC power source.

[0018] In one embodiment, at least one of the first and second flexible contacts may include a roller having a roller mount and a rolling element formed from an absorbent material attached to the roller mount, the rolling element adapted to receive a conductive fluid and subsequently apply the conductive fluid to a surface.

[0019] In one embodiment, the roller may be a split roller having a first rolling body portion arranged to form a first electrode and a second rolling body portion arranged to form a second electrode, the split roller being electrically connected to a power source and the first and second rolling body portions being electrically insulated from each other.

[0020] In one embodiment, at least one of the first and second flexible contacts may comprise an absorbent pad adapted to receive the conductive fluid and subsequently apply the conductive fluid to a surface.

[0021] In one embodiment, at least one of the first and second flexible contacts may comprise a brush. In one embodiment, the brush may comprise a conductive filament.

[0022] In one embodiment, the apparatus may further comprise a separator element formed of a non-conductive material arranged to prevent the first or second flexible contacts from directly contacting the other flexible contact, In one embodiment, the separator element may comprise a shroud extending at least partially around at least one of the first and second flexible contacts.

[0023] In one embodiment, the power source may be an on-board power source contained within or attached to the device casing, hi one embodiment, the on-board power source may be in a power source housing that is removably attached to the device casing.

[0024] In an alternative embodiment, the power supply may be in a power supply housing separate from and electrically connected to the device casing.

[0025] In one embodiment, the device may further comprise a fluid conduit arranged to provide a conductive fluid from a fluid source to each of the first and second flexible contacts. In one embodiment, the fluid source may be a fluid reservoir contained within or attached to the device casing. In one embodiment, the fluid reservoir may be removable from the device casing. In one embodiment, the power source may be in a power supply housing that is removably attached to the device casing, and the fluid reservoir may be located within the power supply housing.

[0026] One embodiment of the apparatus is used to electrochemically clean and passivate welds in an electrically conductive article.One embodiment of the apparatus is used to electrochemically etch designs, patterns, or other forms of markings into the surface of an electrically conductive article.

[0027] Further embodiments or variations of the invention may be disclosed herein or may otherwise become apparent to those of skill in the art through the following disclosure. These and other embodiments are considered to be within the scope of the present invention.

[0028] Next, an embodiment of the present invention will be described with reference to the drawings. [Brief description of the drawings]

[0029] [Figure 1A] FIG. 1 illustrates one embodiment of the present invention. [Figure 1B] FIG. 1 illustrates one embodiment of the present invention. [Diagram 2] FIG. 1 illustrates desired and undesired reactions. [Diagram 3] FIG. 4 is a circuit diagram of an alternative embodiment of the present invention. [Figure 4] FIG. 4 is a circuit diagram of an alternative embodiment of the present invention. [Diagram 5] FIG. 4 is a circuit diagram of an alternative embodiment of the present invention. [Figure 6A] 4 is a voltage waveform graph of one embodiment of the present invention. [Figure 6B] 4 is a voltage waveform graph of one embodiment of the present invention. [Figure 6C] 4 is a voltage waveform graph of one embodiment of the present invention. [Figure 7] FIG. 2 is a circuit diagram of an embodiment of the present invention comprising a switch unit. [Figure 8] FIG. 2 is a circuit diagram of an embodiment of the present invention comprising a switch unit. [Figure 9A] 13 is a voltage waveform graph of an embodiment of the present invention comprising a switch unit. [Figure 9B] 13 is a voltage waveform graph of an embodiment of the present invention comprising a switch unit. [Figure 10A] 13 is a voltage waveform graph of an embodiment of the present invention comprising a switch unit. [Figure 10B] 13 is a voltage waveform graph of an embodiment of the present invention comprising a switch unit. [Figure 10C] 13 is a voltage waveform graph of an embodiment of the present invention comprising a switch unit. [Figure 11A] FIG. 1 illustrates an alternative embodiment of the present invention. [Figure 11B] FIG. 1 illustrates an alternative embodiment of the present invention. [Figure 12] 1A-1C illustrate various embodiments of the first and / or second flexible contacts. [Figure 13] 1A-1C illustrate various embodiments of the first and / or second flexible contacts. [Figure 14] 1A-1C illustrate various embodiments of the first and / or second flexible contacts. [Figure 15] 1A-1C illustrate various embodiments of the first and / or second flexible contacts. [Figure 16] 1A-1C illustrate various embodiments of the first and / or second flexible contacts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] In a first aspect, the present invention relates to an apparatus for applying a conductive fluid to a conductive surface in order to clean, passivate, etch or otherwise treat the conductive surface. Figures 1A and 1B show one embodiment of the present invention, with Figure 1A being a visual depiction and Figure 1B being a circuit diagram. The embodiment of the apparatus shown comprises an apparatus casing 10 and first and second flexible contacts 14, 16 extending from the apparatus casing. The first and second flexible contacts 14, 16 are in electrical communication with opposing terminals of a power source 12 such that one of the flexible contacts is relatively positively charged and the other is relatively negatively charged (said electrical connection is shown by dashed lines in Figure 1A), and each is configured to be capable of transporting a conductive fluid in some manner. The first and second flexible contacts 14, 16 may comprise attachment means for fixing said flexible contacts to the apparatus casing 10 and a flexible applicator portion configured to transport the conductive fluid.

[0031] As used herein, the term "charge polarity" refers to whether an element is positively or negatively charged. As used herein, unless expressly specified otherwise, the identification of the charge polarity of either flexible contact 14, 16 should be interpreted as an identification relative to the other flexible contact. For example, if a first flexible contact is positively charged and a second flexible contact is grounded, the second flexible contact is "negatively charged" relative to the first flexible contact.

[0032] As the circuit diagram of FIG. 1B illustrates, there is no direct electrical connection between the first and second flexible contacts 14, 16. When a conductive fluid is applied to the conductive surface 18 using the first and second flexible contacts 14, 16, an electrical circuit is completed through the conductive surface such that a voltage generated by the power source 12 drives a current through the conductive surface 18 (and any conductive fluid that may be present) between the first and second flexible contacts. The power source 12 may be any particular power source capable of providing sufficient voltage. Although the power source 12 is shown in FIG. 1A as a portable battery pack, this is by way of example only.

[0033] As will be appreciated by those skilled in the art, electrochemical processes such as weld cleaning, surface passivation and electrochemical etching or marking all require the presence of a particular conductive fluid and the formation of a circuit that allows electricity to flow, thereby driving an electrochemical reaction between ions dissolved in the conductive fluid and the conductive surface 18. Because the device includes oppositely charged first and second flexible contacts 14, 16, both of which are adapted to carry a conductive fluid, either flexible contact can function as both a "working electrode" and a "return electrode," depending on the desired electrochemical reaction and the relative charge of the flexible contacts. This can be contrasted with prior art configurations that utilize a ground clamp or spring mechanism, which cannot carry or apply a conductive fluid and cannot function as a "working electrode" because they cannot connect directly to the conductive surface 18, limiting the flow of current through any conductive fluid that may be in its vicinity.

[0034] In at least one embodiment of the present invention, there may be a plurality of first flexible contacts 14 arranged electrically in parallel with one another, and / or a plurality of second flexible contacts 16 arranged electrically in parallel with one another. These embodiments are not considered to depart from the scope of the present invention, and any reference to one first or second flexible contact 14, 16 should be considered to be equally applicable to a plurality of first or second flexible contacts, unless otherwise specified.

[0035] It is believed that embodiments of the present invention may enable a user to electrochemically clean and passivate welds and electrochemically etch designs, patterns or other forms of markings on a conductive surface of an article without the need for ground clamps, ground spring mechanisms or conductive workbenches. This may allow a user to use an apparatus with significantly improved mobility and flexibility compared to prior art tools that require ground clamps and are therefore tethered in place. Users may also be able to use embodiments of the apparatus on ladders, in harnesses, or in other difficult to access or restricted movement situations without the risk of ground clamps and cables blocking their movement.

[0036] Those skilled in the art will appreciate that electrochemical processes require a particular electrical potential to occur at a useful rate. In at least one embodiment, power supply 12 may be a power supply capable of providing at least 12 volts. In further embodiments, power supply 12 is capable of providing at least 18 volts.

[0037] Desired and undesired reactions Referring to FIG. 2, there is shown a portion of an embodiment of the present invention arranged for use in cleaning or polishing a conductive surface. Shown are first and second flexible contacts 14, 16, a conductive surface 18 including a bulk material 18A and an upper surface layer 18B, and a conductive fluid 20. In some embodiments, the surface layer 18B may be an oxidized material, a shaded weld or other deposit on the conductive surface 18, thus covering the bulk material 18A. In other embodiments (not shown), the surface layer 18B may be an upper layer of the conductive surface 18 that is removed, such as by an etching process, to expose the underlying bulk material 18A. Although not shown, those skilled in the art will appreciate that the flexible contacts are oppositely charged with respect to each other, and that the appropriate charge polarity for a desired reaction will depend on the nature of the conductive surface, the particular electrochemical process applied thereto, and the type of conductive fluid employed. For ease of explanation, the flexible contacts 14, 16 that are appropriately charged to promote the desired reaction 22 may be referred to herein as "active flexible contacts."

[0038] When both the first and second flexible contacts 14, 16 are in contact with the conductive fluid, a reaction process 22, 24 takes place at each flexible contact. The reaction process that occurs at each flexible contact depends on its charge polarity relative to the conductive surface and the other flexible contact, the nature of which is well known in the art. Positively charged ions in solution within the conductive fluid migrate from the positively charged flexible contact through the conductive fluid toward the conductive surface and the negatively charged flexible contact. Similarly, negatively charged ions in solution migrate away from the negatively charged flexible contact toward the positively charged flexible contact and the conductive surface.

[0039] Generally, only one of these processes is the desired process 22, which in the example of FIG. 2 is shown as the surface layer 18B going into solution in the conductive fluid 20, migrating toward the appropriately charged first flexible contact 14, and finally depositing thereon. The charge balance process 24 may include other reactions, such as the evolution of gas or water, which are not detrimental, but may also include the reverse of the desired process 22. For example, as indicated by the curved arrow, the charge balance process 24 may also include redepositing material that has been drawn into solution from the surface layer 18B onto the conductive surface 18, which is undesirable. Undesirable forms of the charge balance process 24 may also include dissolution of material deposited on the second flexible contact 16, migration of these ions to the conductive surface 18, and subsequent deposition.

[0040] Those skilled in the art will appreciate that the properties of the conductive surface 18 (including the properties of the bulk material 18A and surface layer 18B), the conductive fluid 20, and the desired and undesired processes 22, 24 may vary between applications of an embodiment of the invention. Those skilled in the art will further appreciate that these various properties are generally well known in the art.

[0041] Accelerating desired processes / improving undesired processes The time it takes for an electrochemical reaction to occur at each reaction site depends on the rate of movement of the ions in the solution and the length of the path the ions must travel. The ion rate depends on the nature of the ions, the concentration of the solution, the temperature, and the applied potential gradient. With further reference to FIG. 2, without limiting the scope of the invention by theory, if the desired process 22 involves dissolution of a surface material (e.g., by etching, cleaning, and / or polishing), the "path length" of the desired process 22 is believed to be the distance between the first flexible contact 14 and its immediately proximate surface layer 18B.

[0042] Conversely, one form of undesirable process (represented by the curved arrows in charge balance process 24) requires that the dissolved ions in surface layer 18B first migrate through conductive fluid 20 toward second flexible contact 16, because the dissolved ions must first leave the influence of first flexible contact 14, and only then can they migrate to conductive surface 18 and deposit thereon. An alternative form of undesirable process (dissolution of material on second flexible contact 16 and subsequent deposition on conductive surface 18) requires three steps: dissolution, migration, and deposition. In general, it has been found that undesirable processes take longer to complete than desired process 22 does. In some embodiments, the undesirable process may take at least twice as long as the desired process.

[0043] In configurations (not shown) where the desired process 22 is the deposition or plating marking of a material onto a conductive surface, the desired process 22 attracts ions already dissolved in the conductive fluid 20. The ions migrate away from the appropriately charged flexible contact and toward the conductive surface 18 as well as the other oppositely charged flexible contact. Deposition of the ions onto the other flexible contact or the pull back into solution of the material deposited on the conductive surface 18 is typically an undesirable process. As with the previous example, it is envisioned that the undesirable process (e.g., migration of ions from the first flexible contact 14 or conductive surface 18 to the second flexible contact 16 and subsequent deposition) will take longer to complete than the desired process 22.

[0044] Based on the above, a particular electrochemical process (i.e., a desired process 22 and its associated charge balancing and / or undesired processes 24) applied to a conductive surface 18 having particular properties and utilizing a particular conductive fluid 20 and applied voltage will have a particular desired process completion time (T C ). T D,min ≦T C <T U Here, T D,minis the minimum time required for the desired process 22 to proceed, and T U is the time required for the undesired process 24 to proceed. C T D,min and T U It will be appreciated that the range of time values ​​between

[0045] In one embodiment, promotion of the desired reaction 22 and limiting the charge balance reaction 24 may be accomplished by rapidly switching the charge polarity of the first and second flexible contacts 14, 16 such that the first and second flexible contacts 14, 16 alternately become positively or negatively charged relative to one another. Without wishing to limit the scope of the invention by theory, it is envisioned that by switching the charge polarity of the first and second flexible contacts 14, 16 such that each unbroken period spent at a particular charge polarity is longer than the minimum time required for the desired process but shorter than the time required for the undesired process, the desired process 22 may be selectively promoted over the undesired process, thereby reducing, negating, or at least ameliorating the need for a direct return electrode such as a ground clamp.

[0046] For ease of explanation, the cleaning, etching or polishing configuration will be described in terms of a configuration in which the surface layer 18B dissolves to form positively charged ions, such as when the surface layer to be removed comprises a metal. The apparatus is powered such that the first flexible contact 14 is negatively charged and the second flexible contact 16 is positively charged. The surface layer 18B is drawn into solution and its ions move towards the first flexible contact 14, some of which move across the conductive fluid 20, leaving the influence of the first flexible contact 14 and subsequently being influenced by the positively charged second flexible contact. However, before these ions can be redeposited, the charging polarity of the power supply 12 is reversed so that the first flexible contact 14 is now positively charged and the second flexible contact 16 is negatively charged.

[0047] With respect to a marking or electroplating configuration, as an illustrative example, the apparatus may be powered such that the first flexible contact 14 is positively charged and the second flexible contact 16 is negatively charged. Positively charged ions already dissolved in the conductive fluid 20 are urged by the positively charged first flexible contact 14 to deposit on the conductive surface 18 and migrate from the first flexible contact towards the second flexible contact 16. However, by reversing the charge polarity of the flexible contacts 14, 16 before the ions can plate thereon, the plating or deposition of dissolved material onto the now positively charged second flexible contact 16 is reduced, inhibited, or at least ameliorated.

[0048] Although the above examples are described with reference to positively charged ions being drawn into or deposited from solution, those skilled in the art will appreciate that this is merely exemplary and that it is within the scope of the invention disclosed herein to adapt the device to draw negatively charged ions into or deposit them from solution.

[0049] In further embodiments, the device may be configured such that the voltage at the first flexible contact 14 when the first flexible contact is positively charged and the voltage at the second flexible contact 16 when the second flexible contact is positively charged are substantially similar in magnitude to each other. In further alternative embodiments, the device may be configured such that the voltage at the first flexible contact 14 when the first flexible contact is negatively charged and the voltage at the second flexible contact 16 when the second flexible contact is negatively charged are substantially similar in magnitude to each other. In either embodiment, the device may be further configured such that each of the flexible contacts 14, 16 spends a substantially similar amount of time either positively or negatively charged to reduce or at least ameliorate any "DC bias" that may occur.

[0050] The continuous period of time spent charging to a particular charging polarity is referred to herein as a "charging polarity period" (T P), i.e., the period of time for switching the charge polarity of the flexible contacts 14, 16. In an ideal embodiment, the charge polarity period T P is the desired process completion time T C is equal to.

[0051] In an alternative embodiment, the first flexible contact 14 may be configured to promote the desired reaction 22 by providing a reduced contact area compared to the second flexible contact 16. As will be appreciated by those skilled in the art, the overall reaction rate of each of the desired reaction 22 and the charge balance reaction 24 depends at least in part on the total current flowing through the completed circuit, but the rate of the desired reaction 22 or charge balance reaction 24 per unit area depends on the current density. Thus, by making the contact area of ​​the first flexible contact 14 substantially smaller than the contact area of ​​the second flexible contact 16 such that the current density immediately proximal to the first flexible contact 14 is increased relative to the current density immediately proximal to the second flexible contact 16, the rate of the desired reaction 22 per unit area is increased. Conversely, any products of the charge balance reaction 24 will be spread over a relatively large surface area without increasing the amount produced, allowing any undesirable deposits to be gradually thinned and substantially removed. In further embodiments, the contact area of ​​the first flexible contact 14 may be at least twice the contact area of ​​the second flexible contact 16. Those skilled in the art will appreciate that the ratio between the contact areas of the first and second flexible contacts 14, 16 may also depend on various factors, such as the reaction rates per unit area of ​​the desired and undesired reactions 22, 24.

[0052] power supply In one embodiment, and with reference to FIG. 3, switching the charge polarity of the first and second flexible contacts 14, 16 may be enabled by utilizing an alternating current (AC) power source 12A. It is believed that an AC power source provides the advantage that switching the charge polarity to effect the promotion of the desired reaction 22 may be accomplished without the need for complex electrical circuitry. As will be appreciated by those skilled in the art, the AC power source 12A has an associated power output frequency, the reciprocal of which is the power output period (T 出力The power output period is equal to the length of time it takes for a particular flexible contact 14, 16 to fully cycle through its charge polarity, e.g., from positively charged to negatively charged and back again, and is thus the power output period T 出力 is the charging period T P Thus, in a further embodiment, AC power source 12A may be selected or configured such that its power output is at a frequency (f) that complies with the following criteria:

number

[0053] AC power sources are not always practical, especially when portability is desired. Thus, in an alternative embodiment of the invention, and with reference to FIG. 4, the power source 12 may be a direct current (DC) power source 12B. It is contemplated that the use of a DC power source 12B may be particularly beneficial in providing an embodiment of the device that is portable. In some embodiments, the DC power source 12B may be one or more of a fuel cell, a battery, a power cell, or an alternative form of standalone DC power source.

[0054] Embodiments of the present invention utilizing DC power source 12B may be configured to promote a desired reaction 22 by reducing the contact area of ​​first flexible contact 14.

[0055] Switching charging polarity using a DC power supply The DC power source 12B, as such, is not capable of switching charge polarity to facilitate the desired reaction 22. Therefore, to enable this functionality without sacrificing the potential portability offered by a DC power source 18B, such as a fuel cell or battery pack, in an alternative further embodiment, referring to FIG. 5, the device may further comprise a switch unit 26 between the DC power source 12B and the flexible contacts 14, 16, and a switch controller 28 connected to the switch unit. The switch unit may be electrically connected to a voltage output terminal 30, a ground terminal 32, and the first and second flexible contacts 14, 16. In such an embodiment, the switch unit 26 may have a first configuration in which the first flexible contact 14 is positively charged and the second flexible contact 16 is negatively charged, and a second configuration in which the first flexible contact is negatively charged and the second flexible contact is positively charged. The switch controller 28 may be configured to switch the T P =T C So, the charging polarity period T P may be configured to periodically toggle the switch unit 26 between the first and second configurations according to

[0056] In some embodiments, the switch controller 28 can toggle the switch unit 26 by periodically issuing a single "toggle" signal. In such embodiments, the charging polarity period may be equal to the "clock period" of the switch controller 28, which is the period between signal pulses. In some alternative embodiments, the switch controller 28 can toggle the switch unit 26 by alternately issuing two different signals, a "toggle from first configuration to second configuration" signal and a "toggle from second configuration to first configuration" signal. As will be appreciated by those skilled in the art, in such embodiments, the "clock period" of the switch controller is the period between two successive instances of the same signal (e.g., two successive instances of issuing a "toggle from first configuration to second configuration" signal), and is therefore twice the length of the charging polarity period.

[0057] In one embodiment of the invention comprising the switch unit 26 and the switch controller 28, the first and second flexible contacts 14, 16 may have respective contact areas that are substantially similar in size to improve or otherwise reduce the induction of DC voltage bias during use of the device. In the embodiment shown in FIG. 5, the voltage output terminal 30 and the ground terminal 32 are shown as respective terminals of the DC power source 12B, however, one skilled in the art will appreciate that other circuit components may be positioned between the DC power source 12B and the switch unit 26. As used herein, the terms voltage output terminal 30 and / or ground terminal 32 may refer to the respective terminals immediately "upstream" or "downstream" of the switch unit 26 (depending on whether the other circuit component provides the voltage output terminal 30 and / or the ground terminal 32).

[0058] FIG. 6a shows the electrode potential at the first flexible contact 14, while FIG. 6b shows the electrode potential at the second flexible contact 16 when the switch unit 26 is implemented, assuming no losses, for an 18 volt DC power supply 12B. Finally, FIG. 6c shows the voltage across both flexible contacts 14, 16. The overall voltage waveform is such that the first flexible contact 14 is the default "positive" terminal, but those skilled in the art will understand that this is merely a convention and does not limit the scope of the invention. As will be appreciated by those skilled in the art, the "peak-to-peak" voltage across both contacts is 36 volts, double the voltage of the 18 volt DC power supply 12B.

[0059] 7, in one embodiment, the switch unit 26 may comprise an array of switches having at least a first switch 26A, a second switch 26B, a third switch 26C, and a fourth switch 26D. The first switch 26A may form a closeable circuit segment between the voltage output terminal 30 and the first flexible contact 14, the second switch 26B may form a closeable circuit segment between the voltage output terminal 30 and the second flexible contact 16, the third switch 26C may form a closeable circuit segment between the first flexible contact and the ground terminal 32, and the fourth switch 26D may form a closeable circuit segment between the second flexible contact and the ground terminal. In such an embodiment, the switch controller 28 can be configured such that toggling the switch unit 26 to a first configuration includes closing the first and fourth switches 26A, 26D and opening the second and third switches 26B, 26C, and toggling the switch unit to a second configuration includes opening the first and fourth switches 26A, 26D and closing the second and third switches 26B, 26C, where closed switches allow electricity to flow and open switches inhibit electricity flow.

[0060] One or more of the switches 26A-26D may comprise a transistor. One or more of the switches 26A-26D may comprise a thyristor and a diode connected in parallel. In one embodiment, the switch unit 26 may comprise a full-bridge inverter switch.

[0061] Interference Mitigation In at least one embodiment of the invention that includes a switch unit 26, the electrode potential at each of the first and second flexible contacts 14, 16 may be a square waveform. An example of each waveform is shown in Figures 6a and 6b, where the switch controller 28 toggles the switch unit 26 between a first configuration and a second configuration every 2 milliseconds (i.e., T P=2 ms). One skilled in the art will appreciate that the voltage and charging polarity periods are chosen arbitrarily and, for example, for purposes only. When toggling at high frequencies, the sudden spikes or dips in voltage occurring at the edges of each "square" of the waveforms shown in Figures 6a-6c can induce high levels of electromagnetic interference in nearby electrical circuits and other electronic equipment, with the amount of electromagnetic interference generated being at least partially proportional to the instantaneous rate of change of the voltage. While embodiments of the invention that generate electromagnetic interference may be sufficient in some situations, they may not be appropriate when the device is used in areas with sensitive electronic equipment, for example.

[0062] To remedy this, one embodiment of the apparatus may be configured to reduce the voltage across the first and second flexible contacts when the switch unit 26 is toggled, such that the instantaneous rate of change of voltage across the first and second flexible contacts 14, 16 caused by the toggling of the switch unit 26 is reduced, thereby reducing or ameliorating the amount of electromagnetic interference generated.

[0063] In one embodiment, referring to FIG. 8, the apparatus may further include a DC-DC converter 34 between the DC power source 12B and the switch unit 26. At least in this embodiment, the voltage output terminal 30 and the ground terminal 32 electrically connecting with the switch unit 26 are respective terminals of the DC-DC converter. At least in this embodiment, the DC-DC converter 34 may be configured to receive a constant voltage input from the DC power source 12B, convert the constant DC voltage input to a pulsed DC voltage output, and provide the pulsed DC voltage output to the switch unit 26 via the voltage output terminal 30. Those skilled in the art will appreciate that the DC-DC converter 34 does not generate an AC output.

[0064] In a further preferred embodiment, the pulse voltage output is formed by alternating maximum and minimum voltages, and the pulse period (T パルス) As used herein, the term "pulse period" refers to the period of time it takes for a pulsed voltage output to be repeated, e.g., the length of time between two successive maximum voltages or two successive minimum voltages.

[0065] In a further preferred embodiment, the pulsed voltage output may include a voltage waveform having an asymptotic slope at a voltage minimum and a non-asymptotic slope elsewhere, such that the voltage waveform is substantially curved at non-minima of the voltage. An example of a waveform having an asymptotic slope at a voltage minimum and a non-asymptotic slope elsewhere is shown in FIG. 9A, where the pulse period T パルス is 2 ms. Although the voltage waveform shown in FIG. 9A includes a minimum voltage of 0 V, this is selected for illustrative purposes only. The minimum voltage may be selected as a value greater than 0 V, such as the voltage waveform of the alternative embodiment of the pulsed voltage output shown in FIG. 9B. Those skilled in the art will appreciate that the voltages and pulse periods shown in FIG. 9A and FIG. 9B are for illustrative purposes only.

[0066] In one embodiment, the charging polarity period T P is the pulse period T パルス In a further embodiment, the integer multiple of the pulse period is an odd multiple. In a further embodiment, the odd multiple of the pulse period may be 1, i.e., the charging polarity period T P is the pulse period T パルス may be substantially equal to

[0067] In one embodiment, the timing at which the switch unit 26 is toggled by the switch controller 28 may be substantially coincident with the minimum voltage to reduce the level of electromagnetic interference generated. If the voltage across the first and second flexible contacts 14, 16 is substantially reduced, the instantaneous rate of change of voltage is significantly reduced when the charge polarity of said flexible contacts is reversed. In a further embodiment, if the minimum voltage is at or near zero, it substantially completely ameliorates the generation of electromagnetic interference.

[0068] Figures 10A and 10B show voltage waveforms for the first and second flexible contacts 14, 16, where the potential is measured as the voltage between the respective flexible contacts 14, 16 and the conductive surface 18, while Figure 10C shows the voltage waveform of the device between the flexible contacts 14, 16 based on the input of an exemplary 18 volt DC power supply 12B. In Figure 10C, the overall voltage waveform is such that the first flexible contact 14 is the default "positive" terminal, although those skilled in the art will understand that this is merely a convention and does not limit the scope of the invention.

[0069] In contrast to Figures 6C-10C, one skilled in the art can appreciate that the instantaneous rate of change of voltage is substantially reduced at each instance of toggling, resulting in substantially improved electromagnetic interference generation. Rather than the voltage across the first and second flexible contacts 14, 16 changing abruptly, the transition is smoothed out to a sinusoidal shape. This, in addition to reducing the generated electromagnetic interference, may be achieved by reducing the voltage across the first and second flexible contacts 14, 16 immediately prior to toggling the charge polarity of the first and second flexible contacts 14, 16.

[0070] As can be appreciated by those skilled in the art, the peak voltage values ​​in Figures 10a and 10b are essentially the same as the voltage output of DC power supply 12B, such that the peak-to-peak voltage (based on an 18 volt DC power supply 12B input) is 36 volts. For a voltage waveform that substantially approaches a sine wave, the "useful" voltage (which is the RMS voltage) is approximately 12.6 volts.

number

[0071] Power and Fluid Source Design 11A, the power source 12 may be an on-board power source 36. In such an embodiment, the device may be a fully portable device. In a further embodiment, the on-board power source 36 may be within a power source housing 38 that is removable from a handle portion 40 of the device, with the first and second flexible contacts 14, 16 extending therefrom.

[0072] 11B, the power source 12 may be located within a power source housing 38 spaced from and electrically connected to a handle portion 40 of the device from which the first and second flexible contacts 14, 16 extend. The power source housing 38 may be electrically connected to the handle portion of the device by one or more flexible cables. Such an embodiment may allow for use of the device over extended periods of time.

[0073] In one embodiment, the device may further comprise a fluid conduit 42 arranged to deliver a conductive fluid from a fluid source 44 to at least one of the first and second flexible contacts 14, 16. This may allow for at least a partially continuous flow of conductive fluid to the first and second flexible contacts 14, 16, eliminating or at least ameliorating the need to immerse the first and second flexible contacts in a container of said conductive fluid. The delivery of the conductive fluid through the fluid conduit 42 may be manual (e.g., actuated by a user-operated button or switch) or automatic. The delivery may be pressure-driven by one or more pump units or the like. In a further embodiment, the fluid source may be a fluid reservoir 46 contained within or attached to the device casing 10 and in fluid communication with the fluid conduit 42. In a further embodiment (not shown) in which the device also comprises a power source 12 in the power source housing 38, the fluid reservoir 46 may be located within the power source housing.

[0074] Flexible contact design Generally, referring to FIG. 12, the first and second flexible contacts each comprise a mounting means 48 for mounting to the device casing 10 and receiving electrical current from the power source 12, and a flexible applicator portion 50 extending therefrom and adapted to apply a conductive fluid to the conductive surface 18. The first and second flexible contacts 14, 16 are further adapted to allow electrical current to flow from the power source 12 through the respective flexible contacts and into the conductive fluid. In some embodiments, this may be accomplished by a conductive element contacting or projecting into the flexible applicator portion 50 and thus contacting the conductive fluid carried therein. In alternative embodiments, the flexible applicator portion 50 may be constructed from a conductive material, thereby allowing electrical current to flow along the flexible applicator portion 50 along with or instead of flowing through the loaded conductive fluid. In some embodiments, the mounting means 48 may be adapted to receive a conductive fluid through a fluid conduit 46.

[0075] 12, in one embodiment, the flexible applicator portion 50 may include an absorbent pad 50A at the end of the attachment means 48. The embodiment may also include a conductive element 52. The absorbent material acts as a fluid transport means, transporting the conductive fluid and enabling its application to a conductive surface (not shown).

[0076] In one embodiment, referring to FIG. 13, the flexible applicator portion 50 of at least one of the first and second flexible contacts 14, 16 may be a roller element comprising an absorbent material and mounted on a mounting means 48. As in the embodiment comprising the absorbent pad 50A, the absorbent material of the roller element 50B functions to transport the conductive fluid. In a further embodiment, referring to FIG. 14, each of the first and second flexible contacts 14, 16 may be provided in the form of a split roller having a first mounting means 48-1 and a first roller element 50B-1 arranged to form the first flexible contact 14, and a second roller means 48-2 and a second roller element 50B-2 arranged to form the second flexible contact 16. In one embodiment, the split roller may comprise one or more central portions 54 to provide some structural rigidity. In such an embodiment, the central portion 54 is non-conductive to ensure that the first and second roller elements 50B-1, 50B-2 are electrically isolated from one another.

[0077] In one embodiment, referring to FIG. 15, the flexible applicator portion 50 of at least one of the first and second flexible contacts 14, 16 may be a brush. In a further embodiment, the flexible applicator portion 50 of the brush may comprise a conductive filament 50C. In a further embodiment, the brush may be extendable and / or retractable. The extension and / or retraction may be manual or driven by a motor. The extension and / or retraction may be automated by a switch controller based on a sensor input to sense the extent to which the brush has worn from use.

[0078] As will be appreciated by those skilled in the art, the flexible applicator portion 50 of the first and second flexible contacts 14, 16 is flexible. This helps to promote adequate and proper contact with the conductive surface 18 by both contacts 14, 16, necessary to ensure that an electrical circuit is completed. However, depending on the size, type and configuration of the first and second flexible contacts 14, 16, the flexible contacts may be at risk of flexing, bending or otherwise deforming towards each other. If they directly contact each other, the circuit may be prematurely completed, leading to a short circuit. In one embodiment, referring to FIG. 16, the device may further comprise a partition element 56 formed of a non-conductive material arranged to prevent the first or second flexible contacts 14, 16 from directly contacting the other flexible contact. In a further embodiment, referring again to Figure 15, the partition element 56 may comprise a shroud that extends at least partially around at least one of the first and second flexible contacts 14, 16. In some embodiments, the shroud may be expandable and / or contractible. Although the partition element 56 depicted in Figure 15 is shown with a cutout, this is for purposes of illustration and clarity only.

[0079] Although the present invention has been described with reference to the above preferred embodiments, those skilled in the art will appreciate that the present invention is not limited to those embodiments and may be embodied in many other forms, variations and modifications other than those specifically described. The present invention includes all such variations and modifications. The present invention also includes all of the steps, features, components and / or devices referred to or indicated in this specification, individually or collectively, and includes any and all combinations of the steps or features or any two or more of them.

[0080] In this specification, unless the context clearly indicates otherwise, the word "comprising" is not intended to have the exclusive meaning of words such as "consisting only of" but has a non-exclusive meaning in the sense of "including at least". The same applies to other forms of words such as "comprise", with the corresponding grammatical changes.

[0081] Other definitions of selected terms used herein may be found in the detailed description of the invention and may be applied throughout. Unless otherwise defined, all other scientific and technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0082] Any promises made herein should be understood to relate to some embodiments of the invention and are not intended to be promises made with respect to the invention in all embodiments. If there are promises that are deemed to apply to all embodiments of the invention, the applicant / patent owner reserves the right to subsequently delete them from the specification and will not rely on those promises for the grant or subsequent grant of a patent in any country.

Claims

1. an apparatus casing; first and second flexible contacts extending from the casing, each having a mounting means and a flexible applicator portion extending from the mounting means, each being electrically connected to a power source; and Equipped with the first and second flexible contacts are each adapted to receive a conductive fluid and subsequently apply the conductive fluid to a surface; the first and second flexible contacts receive power having a periodically varying voltage; the first flexible contact alternately becomes positively and negatively charged relative to the second flexible contact; the second flexible contact alternately becomes negatively and positively charged relative to the first flexible contact; The portable handheld electrochemical processing device, wherein said alternating of each of said first and second flexible contacts occurs simultaneously and in opposite directions.

2. The apparatus of claim 1 , wherein the power source is an alternating current (AC) power source.

3. the power source is a direct current (DC) power source; The device, a switch unit between the power source and the first and second flexible contacts, the switch unit being electrically connected to a voltage output terminal, a ground terminal, and the first and second flexible contacts; a switch controller connected to the switch unit and having a charging polarity cycle; the switch unit having a first configuration in which the first flexible contact is relatively positively charged and the second flexible contact is relatively negatively charged, and a second configuration in which the first flexible contact is relatively negatively charged and the second flexible contact is relatively positively charged; and 2. The apparatus of claim 1, wherein the switch controller is configured to periodically toggle the switch unit between the first configuration and the second configuration at a rate determined by the charge polarity period.

4. a DC-DC converter electrically connected to the power supply and the switch unit; the voltage output terminal and the ground terminal are respective terminals of the DC-DC converter; and The DC-DC converter (i) receiving a constant voltage input from a power source; (ii) converting the constant voltage input into a pulsed voltage output; and (iii) providing the pulsed voltage output to the switch unit via the voltage output terminal; It is configured as follows: Furthermore, the pulse voltage output includes a voltage waveform having a repeating pattern formed by alternating maximum and minimum voltages and having a pulse period; and The apparatus of claim 3 , wherein the charging polarity period is substantially equal to an integer multiple of the pulse period.

5. The apparatus of claim 4 , wherein the charging polarity period is substantially equal to an odd multiple of the pulse period.

6. the pulsed voltage output includes a voltage waveform having an asymptotic slope at its minimum voltage and a non-asymptotic slope elsewhere; and 6. The apparatus of claim 4, wherein the timing at which the switch controller toggles the switch unit substantially coincides with the minimum voltage.

7. 5. The apparatus of claim 4, wherein the voltage waveform is a rectified full-wave sinusoidal waveform.

8. The switch unit comprises an array of switches, the array comprising: a first switch forming a closeable circuit segment between the voltage output terminal and the first flexible contact; a second switch forming a closeable circuit segment between the voltage output terminal and the second flexible contact; a third switch forming a closeable circuit segment between the ground terminal and the first flexible contact; a fourth switch forming a closeable circuit segment between the ground terminal and the second flexible contact; and further wherein toggling the switch unit to the first configuration includes closing the first and fourth switches and opening the second and third switches; and 4. The apparatus of claim 3, wherein toggling the switch unit to the second configuration comprises opening the first and fourth switches and closing the second and third switches.

9. the charging polarity period is equal to the desired process completion time; Furthermore, the desired process completion time (T Ｃ ) but the following: T Ｄ，ｍｉｎ ≦T Ｃ <T Ｕ is defined as follows: Ｄ，ｍｉｎ is the minimum time required for the desired process to proceed, and T Ｕ 4. The apparatus of claim 3, wherein t is the time required for an undesired process to proceed.

10. 4. The apparatus of claim 3, wherein the DC power source is a battery, a power cell, a fuel cell, or other stand-alone DC power source.

11. The device of claim 1 , wherein the flexible applicator portion of at least one of the first and second flexible contacts comprises a roller element including an absorbent material.

12. 10. The device of claim 1, wherein the flexible applicator portion of at least one of the first and second flexible contacts includes an absorbent pad at an end of the attachment means.

13. The device of claim 1 , wherein the flexible applicator portion of at least one of the first and second flexible contacts comprises a brush.

14. The apparatus of claim 13 , wherein the brush comprises a conductive filament.

15. 10. The device of claim 1, further comprising a separation element formed of a non-conductive material positioned to prevent the first or second flexible contact from directly contacting the other flexible contact.

16. The apparatus of claim 15 , wherein the separation element comprises a shroud extending at least partially around at least one of the first and second flexible contacts.

17. 10. The device of claim 1, wherein the power source is an on-board power source housed within or attached to the device casing.

18. 20. The device of claim 17, wherein the on-board power supply is within a power supply housing removably attached to the device casing.

19. 10. The device of claim 1, wherein the power source is within a power source housing spaced apart from the device casing and electrically connectable to the flexible contacts.

20. The apparatus of claim 1 , further comprising a fluid conduit positioned to provide the conductive fluid from a fluid source to each of the first and second flexible contacts.

21. 21. The device of claim 20, wherein the fluid source is a fluid reservoir contained within or attached to the device casing.

22. 22. The device of claim 21, wherein the fluid reservoir is removable from the device casing.

23. the power supply is in a power supply housing that is removably attached to the device casing; and 23. The device of claim 21 or 22, wherein the fluid reservoir is located within a power supply housing.

24. 10. The apparatus of claim 1 used to electrolytically clean and passivate welds on conductive articles.

25. 10. The apparatus of claim 1 used to electrochemically etch designs, patterns, or other forms of markings into the surface of a conductive article.

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