Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2/00—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor
  • A61L2/02—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor using physical phenomena
  • A61L2/14—Plasma, i.e. ionised gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B67—OPENING, CLOSING OR CLEANING BOTTLES, JARS OR SIMILAR CONTAINERS; LIQUID HANDLING
  • B67C—CLEANING, FILLING WITH LIQUIDS OR SEMILIQUIDS, OR EMPTYING, OF BOTTLES, JARS, CANS, CASKS, BARRELS, OR SIMILAR CONTAINERS, NOT OTHERWISE PROVIDED FOR; FUNNELS
  • B67C7/00—Concurrent cleaning, filling, and closing of bottles; Processes or devices for at least two of these operations
  • B67C7/0073—Sterilising, aseptic filling and closing
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
  • H05H1/00—Generating plasma; Handling plasma
  • H05H1/24—Generating plasma
  • H05H1/26—Plasma torches
  • H05H1/32—Plasma torches using an arc
  • H05H1/34—Details, e.g. electrodes, nozzles

Definitions

• DESCRIPTION Process and plasma torch for treating a surface in a cavity, and filling-capping installation relating thereto.
• the present invention relates to a method for treating a surface in a substantially atmospheric pressure in a cavity.
• the present invention also relates to a plasma torch for the implementation of this method.
• the present invention also relates to a filling-capping installation in which the decontamination of the containers is ensured according to the method and with the torch according to the invention.
• decontamination is meant a “treatment” for removing non-living residues and microorganisms, in particular after the surface has undergone the usual washing and rinsing operations.
• sterilization is meant “decontamination” as applied to eliminate microorganisms.
• the present invention relates in particular but not limited to the decontamination of containers and stoppers before filling, in particular in the context of an industrial filling-capping chain.
• the treatment methods of bringing the inner surface of the containers into contact with chemical substances pose many problems, in particular the duration of implementation, the quantities of chemical substances required, the problems of reprocessing or elimination of these substances after their use, the need to then carry out one or more rinses and drying of the container, then to treat the rinsing products.
• the object of the invention is to provide a method and a device of the type indicated at the start which are capable of treating, in particular decontaminating or sterilizing efficiently and quickly a surface in a cavity and in particular the interior surface of a hollow body such than a container or a stopper, and which in particular lends itself well to integration into an industrial bottling chain.
• the method for treating at least one surface in a cavity by means of a plasma torch opening into the interior of the cavity is characterized in that from an arc chamber of the torch , an impulse jet of plasma is generated, so that by sudden expansion of the plasma out of the chamber, the jet produced by an impulse sweeps substantially the entire interior of the cavity.
• the invention is based on the discovery that a plasma jet produced by a brief and powerful pulse, when ejecting this jet into the interior of a container, generally sweeps the entire interior surface of the container and, in most cases, treats and in particular completely decontaminates this surface.
• the cavity can be placed in a confinement or quasi-confinement situation before and during the generation of the jet.
• the properties of the plasma jet are particularly high: low wavelength ultraviolet flash and flash thermal. Thanks to the confinement which is preferably carried out on the hollow body just before the generation of the jet, there is no or very little plasma ejected out of the hollow body, and all the energy communicated to the plasma is dissipated in this hollow body. Furthermore, the shortness of the jet means that the action of the plasma on the walls of the hollow body only applies to the extreme surface of the material, without any degradation of its depth.
• the hollow body to which this decontamination process applies may be a container intended to be filled
• the cavity can also be formed by the inner surface of a stopper which must be perfectly clean just before it is used to close a container.
• the plasma torch for implementing the aforementioned method, comprises an elongated body in which the arc chamber is defined, having an ejection orifice at one end designed to be introduced into the cavity, a proximal main electrode and a distal main electrode connected to each other by a capacitor, spaced axially in the chamber, means for producing a trigger pulse in a priming circuit passing through a part of the arc chamber in the vicinity of the proximal electrode, and supply means for charging the capacitor.
• a small arc forms in a part of the arc chamber in the vicinity of the proximal electrode which is preferably the cathode.
• the resulting ionization for the gas between the main electrodes causes the capacitor to suddenly discharge through a circuit passing through the gas space of the chamber between the electrodes.
• the rapid and intense heating of the gas causes its expulsion from the chamber and throughout the interior space of the cavity.
• the filling-capping installation comprises means for transferring the containers through various successive stations, at least one of these stations being a treatment station comprising a torch according to the second aspect, and relative displacement means between the torch and the container for the introduction and the extraction of the torch relative to the container.
• FIG. 1 is a schematic view, in axial section, of a plasma torch according to the invention, and of certain elements of the associated electrical circuit;
• - Figure 2 is a graph of the current I passing through the main proximal electrode as a function of time t;
• - Figure 3 is a schematic view of the torch producing a plasma jet inside a bottle,
• - Figure 4 illustrates a variant of the electrical circuit;
• FIG. 5 is a partial top view of a filling-capping chain
• FIG. 6 is an elevational view of the station for decontamination and filling of lacons;
• Figures 7 and 8 partially illustrate, in perspective, a means of centering a bottle at two successive functional stages;
• FIG. 9 illustrates the application of the method according to the invention to the decontamination of a plug.
• the torch has an elongated body along an axis 1.
• the body is composed of a proximal part 2 fixed to a support 3 and a distal part 4 of generally cylindrical shape centered on the axis 1.
• the distal part 4 has an outside diameter suitable for being introduced with a suitable clearance, for example two or three millimeters, through the orifice of a container, such as a bottle, to be decontaminated.
• the support 3 is movable parallel to the axis 1 while being itself fixed to a column 6 movable along its own axis parallel to the axis 1.
• the axis 1 is vertical, and the distal part 4 is directed downward to penetrate into a container whose orifice is oriented upward.
• the body 2, 4 defines inside an axial chamber 7 which opens to the outside through the free end of the distal part 4, by an ejection orifice 8.
• the body carries two main electrodes which are exposed in the chamber 7, and more particularly a proximal electrode 9 which is an axial rod-shaped cathode protruding into the chamber 7 from its proximal end, and a distal electrode 11, which is an anode in the example, and which has an annular shape centered on the axis 1.
• the inner radial surface of the anode 11 defines the ejection orifice 8.
• a priming electrode 12 produced in the form of a ring whose radially inner face is exposed in the chamber 7 around the cathode 9.
• the priming electrode is isolated from with regard to any direct or indirect contact with the cathode 9 by a ceramic ring 13 interposed therebetween.
• the priming electrode 12 has an annular projection 14 directed radially inwards and more precisely towards the proximal electrode 9 to establish between the priming electrode 12 and the proximal electrode 9 a narrowed annular space 16 provided for the appearance of a starting arc of the "small arc" type, that is to say a substantially filiform arc.
• the distal electrode 11 is isolated from the priming electrode 12 by a ceramic tube 17 inserted between them and the internal surface 20 of which forms part of the internal surface of the chamber 7 following the electrode 12.
• the main electrodes 9 and 11 are thus normally electrically insulated from one another by the succession of the ceramic ring 13 and the ceramic tube 17, between which is the initiation electrode 12.
• the outer wall of the distal part 4 is constituted by a tube 18 made of conductive material of heat and electricity such as copper.
• the tube 18 is in electrical contact with the anode 11 to serve as a current return means.
• the tube 18 is connected to ground as well as the support 3 and the column 6 as illustrated in 19.
• the proximal part 2 of the body comprises an annular box 21 surrounding the initiation electrode 12 and serving for the circulation of a cooling fluid such as water arriving and leaving by fittings not shown any more.
• the box 21 is in thermal contact with a proximal collar 22 of the electrical and thermal return tube 18.
• the collar 22 forms the base of the proximal part 2 of the body.
• An electrical insulator 23 forms a continuity of insulation between the ring 13 and the ceramic tube 17 all around the axis 1 passing between the initiation electrode 12 and the box 21 then between the electrode 12 and the flange 22, then finally, at one end 24, between the ceramic tube 17 and the copper return tube 18.
• the insulator 23 is chosen to be of sufficient quality and thickness to provide the necessary insulation, in particular between the priming electrode 12 and the box 21, but with a
• a power capacitor C1 is mounted between the two main electrodes 9 and 11. One of the electrodes of the capacitor C1 is electrically connected directly to the cathode 9 and the other electrode of the power capacitor C1 is electrically connected to the anode 11.
• a capacitor d ignition C 0 of lower capacity, comprises an electrode electrically connected directly to the cathode 9 and another electrode connected to the ignition electrode 12 via the secondary 26 of an ignition transformer 27 whose primary 28 is connected to the output terminals of an initiation device 29 intended to produce a voltage pulse in the primary 28.
• the circuit further comprises a rectifier 31 producing between its output terminals 32 and 33 a rectified voltage produced from an alternating voltage of for example 600 volts supplied by a power transformer 34 whose input terminals are connected to the sector 36.
• the output terminal 32 of the rectifier 31 is connected directly on the one hand to the cathode 9 and on the other hand to a first terminal of each of the capacitors C 0 and C x .
• the positive terminal 33 of the rectifier 31 is connected to the other terminal of each of the capacitors C 0 and C x via a respective resistor R 0 and Ri.
• the rectifier 31 permanently recharges the capacitors C 0 and C x .
• the chamber 7 is in communication with the atmospheric air, and permanently receives a low flow 37 of protective gas from the cathode 9 (typically nitrogen, argon for example) injected into the chamber 7 in the vicinity of the cathode 9: the goal sought is to avoid any oxidation of the cathode, which is the most stressed electrode.
• the shielding gas may also be doped with hydrogen.
• the device 29 is controlled so that it produces a current pulse.
• Ions are now present in the space 16 between the electrodes 9 and 12, and are distributed in the latter until allowing the ignition capacitor C 0 to discharge by a current passing between the ignition electrode 12 and the main electrode 9 at a stage corresponding to the area 39 of the curve shown in FIG. 2.
• the priming plasma thus created ends up invading the chamber 7 by making the space between the main electrodes 9 and 11 conductive.
• the power capacitor C ⁇ then discharges very quickly through the main electrodes 9 and 11. and the inter-electrode space situated between them in the chamber 7, as illustrated by peak 41 in FIG. 2. During this discharge , the gas present in chamber 7 is suddenly heated to a temperature of more than 10,000 ° K, which causes its sudden expansion and its ejection through the ejection orifice 8.
• the plasma jet 44 strikes and / or licks, directly and / or by successive reflection the entire interior surface 45 of the container 43.
• the plasma exhaust regulation which can go as far as complete containment of the hollow body, is a significant parameter of the invention.
• the confinement device can play the role of a valve with respect to excessively high pressures which risk causing the hollow body to tear or explode.
• An illustration of such a device is given in FIG. 3 where a valve 47 which normally rests on the orifice of the container (right part of FIG. 3), but which rises from it (left part of FIG. 3) when 'a certain pressure threshold is exceeded in the container.
• a valve 47 which normally rests on the orifice of the container (right part of FIG. 3), but which rises from it (left part of FIG. 3) when 'a certain pressure threshold is exceeded in the container.
• FIG. 1 such a valve is advantageously produced in the form of a ring of suitable mass which is slidably mounted along the distal part 4, therefore around the return tube 18 in the example shown, being prevented from escaping by stop lugs 48 limiting its travel towards the distal end of the torch.
• stop lugs 48 limiting its travel towards the distal end of the torch.
• the resistors R 0 and R x have the function of preventing the power capacitor C x from discharging through the ignition electrode 12 and also of isolating the terminal from the ground. positive of the starting capacitor C 0 .
• These resistors on the other hand, have the drawback of slowing down the charging of the capacitors and of consuming power by the Joule effect.
• the means for charging the power capacitor C x and the means for charging the ignition capacitor C 0 include each a rectifier 49, 51 whose input terminals are connected to two separate secondary 52 and 53 of the power transformer 54.
• the two rectifiers 49, 51 have a first common output terminal 56 connected as in
• One of the preferred features of the process according to the invention is that during the plasma jet (FIG. 3), the main distal electrode 11 is located inside the cavity 50 to be treated while the proximal electrode 9 is found outside.
• WO-A-97/18343 is locked, consisting either in completely introducing into the container a device Plasmogen of small size, either to send a plasma generated outside to the container, or else to use a capacitive plasma by means of an electrode surrounding the container.
• the invention makes it possible to treat a container by means of a plasma generated in situ in an arc chamber of sufficient size so that the plasma obtained by a single pulse is superabundant to effectively treat the entire interior of the container.
• This arrangement made possible by the design of the plasma torch, makes it possible to release the plasma directly inside the hollow body to be sterilized, without external losses, making it possible to easily achieve confinement just before the triggering of the jet.
• the design of the torch finally makes it possible to obtain a distal portion of small diameter (of the order of 10 to 20 mm) compatible with the diameter of the neck of most of the containers concerned.
• FIGS. 5 and 6 illustrate a processing and filling-capping chain for bottles implementing the invention.
• the bottles to be filled arrive via a supply conveyor 59 to a rotary carousel 61 to leave in the form of bottles filled and capped by a starting conveyor 62.
• the bottles 43 can be positioned in cells 63 rotating with the carousel.
• the rotation of the carousel 61 is intermittent with between two stops a step of advance corresponding to the step of succession of the cells 63.
• each bottle 43 thus meets, successively, for example washing, rinsing, drying stations if necessary, then two decontaminating stations 64 and 66, a filling station 67, a capping station, etc.
• each of the decontamination stations 64 and 66 can be equipped with a torch 68 according to the invention.
• the two torches 68 as well as a filling cannula 69 of the filling station 67 can be fixed to the same plate 71 which rises during the rotation of the carousel 61 then descends to immerse simultaneously in three successive bottles 43 on the one hand the two 68 torches at the decontamination 64 and 66 and on the other hand the filling cannula 69 at station 67.
• the container 43 located at station 67 is filled, the two preceding containers are decontaminated in masked time. Each container therefore undergoes two successive decontaminations. This makes it possible to use less power for each plasma jet and to significantly increase the longevity of the electrodes or to increase the pulse rate.
• Figures 7 and 8 illustrate another embodiment for an industrial chain. So as to precisely center the container 43 before the introduction of the torch into the orifice 42 of the container, the container is gripped between the two concave dihedral jaws 72 with a centering clamp 73. The jaws 72 are movable one relative to the other between a withdrawal position shown in Figure 7
• the cavity to be treated is the internal surface of a plug 76, provided with an internal thread 77.
• a valve 47 of appropriate diameter is then used to rest on the free edge 78 of the plug 76.
• the torch penetrates relatively little into the interior space of the latter.
• the principle of decontamination remains the same, however. Tests have shown that even the hollows of the net 77 were properly decontaminated without the mechanical quality of the surface of the net being degraded.
• the invention is applicable to unit decontamination, for example in the laboratory.
• the industrial application of the invention has been illustrated in the form of a station in a machine comprising multiple stations.
• the invention is also applicable in the form of a specific machine intended for example to be inserted between two pre-existing machines in an initially traditional installation.

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• 2000
  • 2000-04-17 FR FR0004947A patent/FR2807912B1/fr not_active Expired - Fee Related
• 2001
  • 2001-04-17 WO PCT/FR2001/001168 patent/WO2001080607A1/fr not_active Application Discontinuation
  • 2001-04-17 AU AU2001252348A patent/AU2001252348A1/en not_active Abandoned
  • 2001-04-17 EP EP01925663A patent/EP1277377A1/de not_active Withdrawn
  • 2001-04-17 US US10/257,770 patent/US20040035838A1/en not_active Abandoned

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