The invention relates to a treatment arrangement for the treatment of a surface of a body with a dielectric barrier plasma, having an electrode arrangement in which at least one electrode is disposed in a base section of the electrode arrangement, is fully shielded with respect to the surface to be treated by a dielectric, and extends by a terminal conductor into a contacting projection of the dielectric, and having a contacting element having a receiving opening for the contacting projection and a lever arrangement for opening and closing the receiving opening and for contact pressure on a contact pin through a prefabricated recess in the dielectric onto the electrode for guiding a terminal of a high-voltage AC source onto the electrode.
It has long been known that dielectric barrier plasma discharge of a surface of a body can have a positive influence on the surface. For instance, surfaces made of a wide variety of different materials can be disinfected and/or prepared for acceptance of adhesives, paints or the like by means of a low-temperature plasma discharge, like a dielectric barrier plasma discharge. Also known is the treatment of surfaces of the skin of living bodies with a dielectric barrier plasma discharge, which can achieve either disinfection or an increase in microcirculation in the skin, and hence also improved wound healing.
For the generation of a dielectric barrier plasma, the electrode of the treatment arrangement is supplied with high-voltage AC. While the electrode arrangement was first connected via a suitable high-voltage cable to a treatment device in which the high-voltage AC was generated, an idea that has increasingly been pursued is that of designing such an electrode arrangement in readily exchangeable form, so that, especially for the treatment of surfaces of the skin, it was possible after a treatment to replace the used electrode arrangement rapidly and easily with a new, sterile-packed electrode arrangement.
Such a treatment arrangement having the features mentioned at the outset is known, for example, from DE 10 2014 013 716 A1. The dielectric of the electrode arrangement has a contacting projection into which the electrode extends by a terminal conductor. In the contacting projection, the dielectric is provided with a recess through which a small surface area of the terminal conductor is exposed as the base of the recess. In use, a contacting pin of the contacting element projects into the recess and contacts the exposed surface of the terminal conductor at the end face, by means of which the high-voltage AC is fed in via the contact pin. The contacting element encloses the arrangement composed of contact pin and recess in the dielectric with an insulating housing, the receiving opening of which for the contacting element can be closed with the lever arrangement, such that contact safety with respect to the high-voltage supply is assured.
EP 3 320 759 B1 discloses an electrode arrangement in which two electrodes are arranged alongside one another in the base section. The two electrodes are fully embedded into the dielectric and hence also insulated from one another by the dielectric. While it is known that two electrodes in an electric arrangement can be connected to the different terminals of a high-voltage AC source, such that one of the electrodes receives the high-voltage phase and the other electrode is at ground potential, EP 3 320 759 B1 envisages supplying both electrodes with the mirror-image phases of the AC voltage source. This achieves the effect that, in the vicinity of the electrodes, twice the amplitude of the high-voltage AC signals arises, whereas the excitation fields are eliminated within a short distance from the electrodes, such that there is a considerable reduction in electromagnetic fields that disrupt the environment. In order not to allow the contacting element to become too large, it is envisaged that the terminal conductors of the two electrodes be allowed to run parallel to one another in the very narrow contacting projection, and that they be contacted there with contact pins of the contacting element. However, the result of this is that the contacting pins must be arranged close to one another. However, voltage amplitudes of 20 kV, for example, that are used here require a minimum distance from one another that is a function of the length of the distance through the air between the contact pins or the terminal conductors that is required for prevention of sparkover. This distance can be observed when the dielectric has one contacting projection for each electrode that extend from the base section of the electrode arrangement in different directions. However, this necessitates the use of two contacting elements that in practice lead to doubling of the complexity.
The objective underlying the invention is thus that of designing a treatment arrangement of the type mentioned at the outset with at least two electrodes in the electrode arrangement such that they can be contacted with a minimum level of complexity.
For achievement of this object, a treatment arrangement of the type mentioned at the outset is characterized in that that the electrode arrangement has at least two electrodes that are disposed in the base section and are isolated from one another by the dielectric and each extend by a terminal conductor into the contacting projection, in that there is one recess in the dielectric and one contact pin for each terminal conductor, in that at least one of the contact pins in the contacting element is coated with a dielectric sheath and is designed with a non-insulated end face for establishing contact with the corresponding electrode and in that the at least one dielectric sheath is oversized with respect to the corresponding recess in the dielectric, by virtue of which the sheath, by means of the lever arrangement, is press-fitted into the dielectric so as to avoid an air gap when the non-insulated end face of the contact pin contacts the corresponding electrode.
The design of the invention ensures that the contact pin with its dielectric sheath rests in the dielectric without an air gap, such that there is no direct pathway through the air between the contact pins for the at least two electrodes or the at least two electrodes themselves. Instead, the relevant minimum distance is determined to a crucial degree by the dielectric properties of the dielectric and of the dielectric sheath.
The invention is employable when the at least two electrodes are connected to an AC voltage source in a conventional manner, i.e. one electrode to an AC voltage phase and the other electrode to ground. In that case, it is not absolutely necessary to provide the contact pin connected to the ground connection of the high-voltage source with a dielectric sheath. It will be appreciated that flashover security is increased when this contact pin too, in the inventive manner, is provided a dielectric sheath that is oversized relative to the corresponding recess in the dielectric.
The present invention is particularly appropriate in the case in which the electrode arrangement has two electrodes that are connected to opposite phases of an AC voltage. In this case, owing to the doubling of the maximum potential difference, it is particularly necessary to provide both contact pins with the dielectric sheath of the invention in order to embed the contact pins into the dielectric effectively without an air gap when the connection with the corresponding electrodes is established via the end faces of the contact pins.
In one modification of the described embodiment with two electrodes driven in antiphase, it is also possible to provide a ground electrode as third electrode in the electrode arrangement. It may be appropriate here to arrange the ground electrode, with respect to the two electrodes driven in antiphase, in a different position in a multilayer structure of the electrode arrangement, such that the ground electrode comes to rest in the dielectric between the electrodes driven in antiphase and the surface to be treated. It will be appreciated that the ground electrode is insulated with respect to the antiphase electrodes by the dielectric. The ground electrode here has apertures that enable the formation of what is called a surface plasma on account of the excitation field that extends through the openings in the ground electrode.
For the present invention, however, preference is given to the design with two electrodes driven in antiphase, for which the surface to be treated or the corresponding body form a counterelectrode. For this purpose, the body may be grounded by a ground connection. In general, it is sufficient when the body, on account of its mass, constitutes a “floating” ground electrode/counterelectrode.
In one embodiment of the invention, the dielectric sheath with at least one gradation is formed with at least two different outer cross sections, with the dimension of the outer cross section being reduced toward the non-insulated end face. It is correspondingly possible to provide the recess of the dielectric with a corresponding gradation. In the interaction of the dielectric sheath with the recess, it is possible to ensure an improved and safer press fit of the sheath in the recess.
This purpose is also served by a design in which the inner cross section of the dielectric, relative to the outer cross section of the dielectric sheath that is assigned to it in the contact position, is at a sharp angle in axial direction of the contact pin, resulting in a funnel-like insertion of the sheath into the recess.
The inner cross section of the recess and the outer cross section of the sheath are circular in one embodiment, although other cross-sectional shapes, for example a square cross section, are likewise possible.
It may be appropriate for the invention when the electrode arrangement is in planar form and the electrodes in two-dimensional form therein are shielded from the surface to be treated by a planar layer of the dielectric. The shielding from the surface to be treated results from the fact that the dielectric forms a contact surface for contact with the surface to be treated but is preferably structured, in order to form air spaces for the formation of the plasma when the dielectric rests by its contact surface on the surface to be treated. The structuring of the surface may be formed in a manner known per se by pimples, a grid structure, recesses in the form of blind holes or the like.
Especially for treatment of curved or irregular surfaces, it is appropriate when the electrodes and the dielectric are flexible.
The lever arrangement by which the contact pressure of the contacting element on the contacting projection of the dielectric is brought about is appropriately lockable in the closed position. A useful lever arrangement is a lever arrangement known as a rocker switch. In order to increase the safety of the connection established between electrode arrangement and contacting element, the lever arrangement may have a two-arm lever with an axis of rotation and an actuation end on one side of the axis of rotation and a control end on the other side of the axis of rotation, wherein the control end is connected via a swivel joint in a swiveling manner to a wall section that opens and closes the receiving opening and is rotatably mounted on an axis of rotation, wherein the axis of rotation is closer to the receiving opening than the swivel joint. The lever arrangement thus constitutes a knee joint controller, by means of which the wall section can be opened wide to form the receiving opening and, when the receiving opening is closed, exerts a suitable contact pressure on the contacting projection of the dielectric when the contacting projection is correctly positioned in the receiving opening.
It may be appropriate to provide the contacting projection additionally with a mechanical positioning aid in the formed of a shaped-on pin or a shaped depression that interacts with a corresponding pin or a corresponding depression in the contacting element, and only enables the closing of the receiving opening to a possibly locked position of the lever arrangement when the positioning is correct. Correct positioning likewise requires engagement of the contact pin with its sheath into the corresponding recess in the dielectric into the press fit.
The moving wall section that forms the receiving opening may take the form of a hood that covers the contact pins in the closed state of the receiving opening. In one embodiment, this may have a surrounding wall, the circumferential margin of which, in the closed state of the receiving opening, ends parallel to a planar base of the receiving opening. The circumferential margin thus serves to clamp the contacting projection of the dielectric in the receiving opening, and the prestress of the wall section causes the flexible dielectric to be indented by the circumferential margin.
For increasing the safety of the connection between the contacting element and the contacting projection of the electrode arrangement that serves to transfer a high voltage, a first sensor may be provided for the closed position of the lever arrangement, which controls a switch for the stoppage of the feed for the high voltage to the electrodes. The supply of the electrode with high voltage is therefore possible only when the sensor has recognized a closed position of the lever arrangement.
In an analogous manner, a second sensor can detect complete introduction of the contacting projection into the receiving opening when the receiving opening is closed.
This ensures that the contacting element does not conduct any high voltage onto the contact pin when no electrode arrangement at all is connected to the contacting element.
Suitable sensors are, for example, light barriers that interact with corresponding projections on moving parts of the contacting element. For instance, a projection on the lever arrangement can project into an assigned light barrier in order to indicate the closed state of the lever arrangement by breaking of the light barrier. In a similar manner, the contacting projection inserted into the receiving opening, on closure of the receiving opening, can actuate a lever arrangement that has a projection that engages with a second light barrier and breaks the light barrier when the contacting projection is correctly positioned in the receiving opening. It will be appreciated that it is also possible to use light barriers in reverse function, in which the light barriers are not broken when the correct positioning of the contacting projection and/or the correct closure of the lever arrangement has taken place. In a skillful embodiment, the two light barriers may be arranged at a fork-shaped end of a light barrier body having three “prongs”. The two interspaces formed can each be bridged by one of the light barriers. The projections on the moving parts of the contacting element can then, for the respective detection state, engage into a corresponding interspace between the prongs and hence break the respective light barrier, which is evaluated as the sensor signal.
The high-voltage AC signals that excite the plasma field are preferably pulse signals, the pulsewidth of which is significantly shorter than the interval to the next pulse. In practice, the excitation pulses appear as a damped vibration with significantly (for example exponentially) decreasing pulse amplitude, with the damped wave train thus formed likewise taking up only a portion of the interval to the next excitation pulse.
Since only a low current flows in the dielectric barrier plasma discharge, the contacting element can be designed as a standalone device with a battery voltage supply and a dedicated high-voltage generator stage. For the actuation of the two electrodes with antiphase high-voltage signals, for example in the form of vapor-deposited pulse trains, two high-voltage generator stages are required, each of which may have inductivity, for example. The inductivities may have opposite winding, which then results in the antiphase formation of the high-voltage signals.
It will be appreciated that it is also possible to supply the voltage supply cable to the contacting element. In this case too, it is possible to generate the high voltage in the contacting element, such that no transfer of the high voltage to the contacting element is required, but merely supply with a customary supply voltage that is not a high voltage.
Alternatively, it is of course also possible to supply the contacting element with externally generated high-voltage signals. In this case, it is necessary to use high-voltage-safe cables and cable bushings. The invention is to be elucidated hereinafter by working examples shown in the drawing. The figures show:
The treatment arrangement of the invention consists of an electrode arrangement 1 and a contacting element 2.
The electrode arrangement 1, in the working example shown, consists of two electrodes 1a, 1b, that have a planar design and are fully embedded into a dielectric 3. The dielectric 3 that essentially takes the form of a square area in a base section has thin application flaps 4 connected to it in one piece by which the electrode arrangement 1 can be bonded to an area to be treated, for example by adhesive bonding. In this way, the electrode arrangement is especially suitable as wound dressing.
The base section of the dielectric is adjoined, in the middle of one of its sides, by an elongated contacting projection 5 with a distinctly reduced width compared to the maximum width of the dielectric 3. In the contacting projection 5 that forms part of the dielectric 3 and is formed in one piece therewith, a terminal conductor 6a, 6b extends away from each of the two electrodes 1a, 1b, and these are connected in one piece to the corresponding electrode 1a, 1b. The electrodes 1a, 1b and the terminal conductors 6a, 6b are embedded on all sides into the dielectric 3 with its contacting projection 5, such that there is no possibility of contact with the electrodes 1a, 1b and the terminal conductors 6a, 6b. The dielectric 3 thus electrically shields all current-carrying parts of the electrodes 1a, 1b and their terminal conductors 6a, 6b, and prevents direct flow of current from the electrodes 1a, 1b to a counterelectrode outside the electrode arrangement 1. The two electrodes 1a, 1b and their terminal conductors 6a, 6b are in planar form and are insulated from one another along a middle axis 7 by material of the dielectric 3. The middle axis 7 in
In the region of the essentially square footprint of the dielectric 3, it is provided with numerous passage holes 8 that extend from a top side 9 of the dielectric 3 down to a bottom side 10 of the dielectric that forms a contact face for the surface to be treated. The passage holes 8 of the dielectric 3 are flush with passage holes 8′ of the electrodes 1a, 1b that are larger than the passage holes 8, such that the electrodes 1a, 1b are also shielded by the dielectric 3 in the channels formed by the passage holes 8.
As indicated in
The contacting projection 5 has, on its bottom side 10, a projection 13 in the form of a land that runs transverse to the middle axis 7, which, in the manner described below, serves for correct positioning of the electrode arrangement 1 in the contacting element 2.
The contacting element 2 serves for the feeding of the high-voltage signals to the electrode arrangement 1. This has a housing with a lower housing section 16 and an upper housing section 17, which form an essentially closed housing 15 with a receiving opening 18. The receiving opening 18 is closable by a wall section 19 that is mounted in a swivelable manner on an axis 20 which is fixed with respect to the housing 15. Formed in the upper housing section 17 is a hollow 21 into which an actuating lever 22 can be swiveled when the actuating lever 22 closes the receiving opening 18 with the wall section 19. The wall section 19 forms a hood which, on its lower side, forms a margin 23 which is closed laterally and toward the electrode arrangement 1, and which, in the closed state of the wall section 19, is parallel to the planar contacting projection 5 of the electrode arrangement 1 in the contacting state of the electrode arrangement 1 with the contacting element 2. The wall section 19 in the form of a hood has a certain hood height, such that a further axis of rotation 24 is above the fixed axis 20. Above the axis of rotation 24, the wall section 19 is connected to an intermediate link 25 which is connected by a further swivel joint 26 firstly to a projection on the actuating lever 22 and secondly to a tension lever 27 which is in turn mounted by means of a swivel joint 28 which is fixed with respect to housing 15.
Also present in the contacting element 2 is a light barrier holder 33 in which two light barriers are arranged successively between two outer walls and one intermediate wall, which each form one gap that can be bridged by one light barrier. For the interaction with one of the light barriers, the tension lever 27 is provided with a protruding projection 34 in one-piece form. For the interaction with the other light barrier, a two-arm lever 35 is mounted on a fixed rotation axis 36, one lever arm 37 of which projects into the receiving opening 18, while the other lever arm can project into the region of the second light barrier by a free end.
Also apparent schematically from
a show the arrangement according to
Comparison of the enlarged diagrams of
In a similar manner,
If the electrode arrangement 1 is inserted correctly into the receiving opening 18 of the contacting element 2 and the receiving opening 18 is closed correctly by the wall section 19, as illustrated in
The switching states for the two light barriers are shown in a cross section in
The dielectric sheath 30 is produced slightly oversized with respect to the recess 14 shaped in the same way, such that the contact pressure of the wall section 19 causes the dielectric sheath 30 to enter into a press fit in the recess 14. To facilitate the introduction of the dielectric sheath 30 in the press fit of the recess 14, dielectric sheath and recess 14 may be in slightly conical form, so as to result in a funnel-like introduction of the dielectric sheath 30 into the recess 14. In the embodiment shown, the introduction is facilitated in that the dielectric sheath 30 narrows in a stepwise manner towards the end face 46 of the contact pin 31, so as to result in two sections of roughly equal length with outer cross sections that differ in steps. The outer cross section is preferably circular.
The press fit of the dielectric sheath 30 in the recess 14 effectively prevents the formation of an air gap at the transition between dielectric 3 and dielectric sheath 30, since the dielectric 3 and the dielectric sheath 30 are formed with sufficient elasticity. The formation of an air gap directed in longitudinal direction of the contact pin 31 can be even more reliably prevented when the wall of the recess 14 or of the dielectric sheath 30 is provided with fine grooves that run in circumferential direction, as indicated in
The electrode arrangement 1 with the dielectric 3 and the electrodes 1a, 1b is preferably flexible. The electrodes 1a, 1b may be formed by a thin metal foil, but may especially also consist of a synthetic polymer that has been rendered conductive by suitable additives. In this way, dielectric and electrode may consist of related materials that can be efficiently bonded facially to one another, such that the risk of delamination within the electrode arrangement is avoided even when the electrode arrangement is bent to a greater or lesser degree in use.
By contrast,
The contacting element 2′ in this embodiment is designed with an actuating lever 52 in the form of a rocker 54 which is pivotable about a fixed axis of rotation 53 and which has, at one end, the wall section 19 in the form of the hood described, shaped in the same way for contact pressure of the contacting projection 5 of the electrode arrangement 1, while, at the other end of the rocker 54, there is an effective locking button 55, which is elucidated hereinafter. The locking button 55 is mounted in a sliding manner on the lever 56 that is remote from the electrode on the rocker 54, and is under prestress by two compression springs 57 that pushes the locking button away from the lever 56. The lever 58 close to the electrode, which forms the wall section 19, is held by a pair of compression springs 66 supported against the housing 15′ of the contacting element 2′ (
For unlocking, i.e. for opening of the receiving opening 19, for example for the purpose of withdrawing the electrode arrangement 1, the locking button 55 has to be pressed in the direction of electrode arrangement 1 against the force of the compression springs 57. In order to facilitate this, there is a suitable corrugation 61 on the top side of the locking button 55, which makes it difficult for an actuating finger to slip off the locking button.
All other parts of the contacting element 2′ correspond to the corresponding parts of the first embodiment, and are therefore not described here again.
The second working example described in
Number | Date | Country | Kind |
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10 2019 109 940.4 | Apr 2019 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/060447 | 4/14/2020 | WO |