FR2862070A1 - Installation for the continuous surface treatment of plastic, composite, mineral or glass objects in a treatment chamber with the introduction and circulation of a plasmagenic gas - Google Patents

Abstract

An installation for the continuous surface treatment of objects comprises a treatment chamber (1) connected to a suction pump (2) for creating a depression in the chamber and to a system (3, 4) for the introduction and circulation of a plasmagenic gas in the chamber. The installation also includes a system (5, 6, 7) for the creation of electric discharges in the plasmagenic gas. An installation for the continuous surface treatment of objects comprises a treatment chamber (1) connected to a suction pump (2) for creating a depression in the chamber and to a system (3, 4) for the introduction and circulation of a plasmagenic gas in the chamber. The installation also includes, upstream of the chamber relative to the plasmagenic gas flow, a system (5, 6, 7) for the creation of electric discharges in the plasmagenic gas. The lower part of the chamber incorporates a platform (14), for the reception of the objects to be treated, that moves between a position in which it seals the lower part of the chamber and a position in which the platform is separated from the lower part of the chamber by a distance sufficient to be able to place the objects on the platform. An independent claim is also included for the operation of this installation for the continuous surface treatment of an object.

Description

The present invention relates to a continuous treatment plant

of the surface of objects.

  The invention also relates to the method for implementing this installation.

  Installations for treating the surface of objects, in particular made of plastics, are already known, comprising a treatment chamber intended to receive the objects to be treated, connected on the one hand with suction means to create a depression in the chamber and on the other hand to means for introducing and circulating in this chamber a plasmagene gas.

  These installations furthermore comprise, upstream of the chamber, relative to the flow direction of said plasma gas, means for creating electric discharges in said plasma gas, in order to create in the chamber a plasma comprising a certain proportion of atoms. free.

  These free atoms modify the surface of objects by making it adherent with respect to certain coatings.

  The disadvantage of known installations is that they are not able to perform a continuous treatment of objects.

  These must first be placed in the treatment chamber placed in the open air.

  Then you have to empty the room. This operation requires a relatively long duration.

  The plasma treatment can then begin.

  After the end of the treatment, it is necessary to put the chamber in the open air before opening the chamber and unloading the treated objects.

  If one wants to treat a new series of objects, it is necessary to repeat the aforementioned operations.

  The known installations are thus poorly suited to large-scale industrial production and reduced costs.

  The object of the present invention is to overcome the disadvantages of known embodiments by creating a treatment facility that can operate continuously.

  According to the invention, this installation is characterized in that the lower part of the chamber comprises a receiving plate of the objects to be treated, movable between a position in which it closes the lower part of the chamber in a sealed manner and a position in which, the tray is spaced from the lower part of the chamber a sufficient distance to be able to place said objects on the tray.

  This installation can thus be implemented, according to the method characterized by the following steps: loading of objects to be treated, on the movable plate in position io spaced from the chamber, control of the rise of the plate towards the sealed closure position of the chamber controls the suction means for producing a depression in the chamber, controls means for introducing the plasma gas into the chamber and controlling its composition, controls means for generating electric discharges in the gas to create in the chamber a gas containing free atoms in order to treat the surface of said objects, control, after the end of the treatment, means for venting the interior of the chamber, control of the descent of the plate to the position spaced from the lower part of the chamber, unloading the tray and loading it with a new series of objects to be treated.

  This method thus makes it possible to process successive series of objects in a substantially continuous manner.

  The plate is movable between the two positions, under the action of mechanical or electro-mechanical control means, such as a jack.

  Also preferably, the treatment chamber is placed above a compartment enclosing said suction means, the means for introducing and circulating a plasmagene gas in the chamber, the means for creating electric discharges in the plasma gas and a part of the control means of the displacement of the plate.

  According to a particularly advantageous characteristic of the invention, the gas outlet opening of the chamber is covered inside the chamber by a diffusion wall comprising a multitude of small holes, this diffusion wall covering a preponderant fraction of the inner surface of the side wall having the gas outlet opening.

  This diffusion wall makes it possible to uniformly distribute the gas and, in particular, the free active atoms throughout the volume of the chamber, which makes it possible to improve the efficiency of the treatment.

  Other features and advantages of the invention will become apparent throughout the description below.

  In the accompanying drawings, given by way of nonlimiting example: FIG. 1 is a diagram of the treatment plant according to the invention, FIG. 2 is a view showing the internal side face of the chamber equipped with a plate. FIG. 3 is a sectional view along the plane AA of FIG. 2; FIGS. 4 to 9 are diagrams similar to FIG. 1 showing the various steps of the treatment method according to the invention.

  As shown in FIG. 1, the installation for continuous treatment of the surface of objects made of plastic, composite material, mineral material or glass, comprises a treatment chamber 1 intended to receive the objects to be treated connected to firstly to suction means constituted by a vacuum pump 2 to create a vacuum in the chamber 1 and secondly to means, namely a pipe 3 comprising a mass flow controller 4 to introduce and circulate in chamber 1 a plasma gas.

  The installation further comprises, upstream of the chamber 1, relative to the direction of flow of the plasma gas, means, namely a coupler 5 and a discharge tube 6, to create electric discharges in the plasma gas. The discharge tube 6 is extended by a conduit 7 which opens into the chamber 1, through a side wall 8 of this chamber.

  The wall 18 opposite the wall 8 carries a gas outlet pipe 10 which is connected to the vacuum pump 2 which opens outwards by an oil mist filter 11.

  Furthermore, the pipe 10 which serves to evacuate the gases and to create the vacuum is equipped with a suction valve 12 and a valve 13 for venting.

  According to the invention the lower part of the chamber 1 comprises a plate 14 for receiving the objects to be treated, movable between a position in which it closes sealingly through a seal 14a, the lower part of the chamber 1, as shown in FIG. 1, and a position in which the plate 14 is spaced from the lower part of the chamber 1 by a distance sufficient to be able to place said objects 15 on the plate 14, as shown in FIG. 4.

  The plate 14 is movable between the two positions above, under the action of mechanical or electro-mechanical control means, constituted for example by at least one cylinder 16, hydraulic or pneumatic.

  As shown in FIG. 1, the treatment chamber 1 is placed above a compartment 17, forming a frame, enclosing all of the suction means, in particular the vacuum pump 2, the means for introducing and circulating in the chamber a plasmagene gas, in particular the pipe 3 and the flowmeter 4, the means for creating electric discharges in the plasma gas, in particular the coupler 5 and the discharge tube 6, and the lower part of the jack 16.

  As indicated in FIGS. 1, 2 and 3, the side wall 18 which carries the gas outlet duct 10 is internally covered by a diffusion wall 19 comprising a multitude of small holes 20. This diffusion wall 19 covers the opening 21 of the outlet duct 10 and a preponderant fraction of the inner surface of the side wall 18.

  The gas introduced into the chamber 1 may consist of a mixture of oxygen and nitrogen in the proportions of 80% of O 2 and 20% of N 2. However, the oxygen level can vary between 0 and 100%.

  The microwave frequency of the coupler 5 may be equal to 2450 MHz. The gas flow rate can be between 100 N cc / min and 2000 Ncc / min.

  The residual pressure inside the chamber 1, before introduction of the gas is of the order of 5 to 10.10 -3 mbar.

  After introducing the gas, that is to say during the treatment, the pressure inside the chamber 1 is between 0.5 and 5 mbar. The discharges carried out in the gas have the consequence that the gas present in the chamber contains a relatively large proportion of oxygen and nitrogen atoms in the free state.

  These free atoms have the effect of modifying the surface of the objects by improving adhesion or wetting properties vis-à-vis a coating, a varnish, a glue, a decor, etc. .

  The diffusion plate 19 placed at the gas outlet of the chamber 1 makes it possible to homogeneously distribute the gas and in particular the free atoms it contains in the entire volume of the chamber, which has the effect of increase the effectiveness of the treatment.

  We will now describe, with reference to Figures 4 to 9, the treatment method according to the invention, as implemented by the installation that has just been described.

  This method comprises the following steps: loading objects 15 to be treated, on the movable plate 14 in a position spaced from the chamber 1 (see FIG. 4), controlling the rise of the plate 14 towards the sealed position of the chamber 1 (see Figure 5), control of the suction means, that is to say the vacuum pump 2, to achieve a vacuum in the chamber 1 (see Figure 6), control means 3, 4 to introduce the gas in the chamber 1 and controlling its composition, controls means 5 to generate electric discharges 30 in the gas to create in the chamber a gas containing free atoms in order to treat the surface of the objects 15 (see FIG. after the end of the treatment, means for venting the interior of the chamber 1, by closing the valve 6 and opening the valve 7 (see FIG. 8), controlling the descent of the plate 14 towards the position spaced from the lower part of chamber 1 (see f 9), unloading the plate 14 and loading it with a new series of objects 15 to be treated.

  In an installation created by the Applicant, the duration of the different Io phases are as follows: Phase 1: (FIG 4): Loading: 3 s Phase 2: (FIG 5): rise of the plateau: 2 s Phase 3: ( Fig 6): pumping: 10 s Phase 4: (Fig. 7): treatment: 20 s Phase 5: (Fig. 8): venting: 3 s Phase 6 (Fig. 9): unloading: 5 s The installation preferably comprises an automaton coordinating the various steps or phases of the method and including software specific for each type of application to a given material.

Claims (7)

  1. Installation for continuous treatment of the surface of objects made of plastic, composite material, mineral material or glass, comprising a treatment chamber (1) intended to receive the objects to be treated connected on the one hand to suction means (2) for creating a vacuum in the chamber (1) and secondly means (3) for introducing and circulating in this chamber (1) a plasma gas, the installation further comprising upstream of the chamber (1), relative to the direction of flow of said plasma gas, means (5) for creating electric discharges in said plasma gas, the installation being characterized in that the lower part of the chamber (1 ) comprises a plate (14) for receiving the objects to be treated, movable between a position in which, it closes in a sealed manner the lower part of the chamber (1) and a position in which the plate (14) is spaced from the lower part of the cham bre (1) a distance sufficient to place said objects on the tray (14).   2. Installation according to claim 1, characterized in that said plate (14) is movable between the two positions, under the action of mechanical or electro-mechanical control means.   3. Installation according to claim 1, characterized in that said control means comprise at least one jack (16).   4. Installation according to one of claims 2 to 3, characterized in that the treatment chamber (1) is placed above a compartment (17) enclosing said suction means (2), the means (3) ) to introduce and circulate in the chamber (1) a plasma gas, the means (5) for creating electric discharges in the plasma gas and a portion of the control means of the displacement of the plate (14).   5. Installation according to claim 4, characterized in that one of the side walls (8) of the chamber (1) comprises an inlet conduit (7) of the plasma gas having undergone electrical discharges and the side wall (18). ) opposite the wall (8) above carries a conduit (10) for the exit of gases.   6. Installation according to claim 5, characterized in that the outlet opening (21) of the gas is covered, inside the chamber (1) by a diffusion wall (19) comprising a multitude of small holes ( 20), said diffusion wall (19) covering a predominant fraction of the inner surface of said side wall (18).   7. A method for implementing the installation according to one of claims 1 to 6, characterized by the following steps: ts loading the objects to be treated (15) on the movable plate (14) in spaced position of the chamber (1), control of the rise of the tray (14) towards the sealed position of the chamber (1), - control of the suction means (2) for producing a depression in the chamber (1), control of the means (3, 4) for introducing the plasmagenic gas into the chamber (1) and controlling its composition, controls means for generating electric discharges in the gas to create in the chamber (1) a gas containing free atoms in order to treat the surface of said objects (15), control, after the end of the treatment, means for venting the interior of the chamber (1), controlling the descent of the plate (14) towards the position spaced from the lower part of the chamber (1), unloading the tray (14) and loading of it by a new series of objects to be treated (15).