CZ304838B6 - Device for surface treatment by plasma generated under standard pressure - Google Patents

Abstract

In the present invention, there is disclosed a device consisting of a fixed frame (12) for installation by connection to a belt conveyor (15) provided with a grounded plate (16). A movable frame (9) is slidably mounted on the fixed frame (12) wherein an electrically conducting plate with tips and hung within an internal cover of electrically non-conducting material, is connected to said movable frame (9). The internal cover hinge (Z) is provided with a subsystem of synchronization of suspension of the plate with tips with the height of the profile of a treated material passing below the tips.

Description

Equipment for surface treatment of plasma generated under normal pressure

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for plasma treatment generated under normal pressure by high voltage. The device is intended for treatment of products passing under it on a belt conveyor. It is designed for inclusion in a production line with continuous and discontinuous cyclic production, where the uniformity of surface treatment is ensured by its own linear movement. Devices of this type can be used for the surface treatment of various materials, particularly the surfaces of injection molded plastic products.

BACKGROUND OF THE INVENTION

For plasma surface treatment there are technologies producing plasma both under reduced pressure at the level of technical or very high vacuum, and also under atmospheric conditions. The advantage of plasma treatment of the surface is that due to its specific properties, chemical reactions proceed quickly and, under well-designed plasma conditions, the modified surface is not damaged.

A disadvantage of low-pressure plasma techniques is the need for an evacuated chamber where production delays arise due to evacuation and re-aeration of the interior space. Related to this is the necessity of batch processing of products. Both increase costs due to energy and time consumption.

In the case of atmospheric pressure plasma generation technologies, known plasma jet beam technologies - sometimes referred to as APPJ (Atmospheric Pressure Plasma Jet), are formed on a nozzle into which a gas is injected under pressure, which is a high voltage electrode in the nozzle. changed to plasma. This beam is usually short in reach and, in particular, its cross-section is generally small in diameter. This is disadvantageous for the treatment of large surfaces where there is a demand for special devices that move the nozzle over the entire surface to be treated.

Plasma generating devices are also used in the form of a dielectric discharge that occurs between two plates, one of which is covered by a dielectric. The discharge is ignited by a sinusoidal or pulsed energy source. To ensure a stable plasma process, the gap between the electrodes is minimized to a width of a few millimeters, which is unsuitable for plasma larger products.

The equivalent is the Qur'anic discharge, which is generated by applying high voltage to the sharp electrode tips. Linear electrode arrangements are often used to produce a surface corona discharge that is used to change the surface energy of various materials, particularly plastics, fabrics or paper. Koran discharge treatment is an extended treatment method, especially in continuous lines with a fixed distance of the treated surface from the electrodes. However, it cannot be used in cyclic production, such as injection molding, in which three-dimensional bodies are produced in which the surfaces would be unevenly treated due to different distances from the plasma.

With respect to the particular design of plasma treatment devices in particular applications, the following solutions may be mentioned:

Devices for processing substrates such as semiconductors, conductors, and insulating foils by plasma are the subject of U.S. Patent Application Publication 2011005681. electrodes on its opposite side. The gas supply directly to the electrodes is solved by distribution and supply channels between the electrodes. The exhaust gas is solved by the outlet piping in the lower part of the chamber.

The plasma generating apparatus for processing the passing material according to PCT International Application WO 2008032856 consists of a microwave source which is connected by a waveguide to a set of plasma generating nozzles. The material to be processed is guided by rollers under the nozzles.

The atmospheric pressure plasma treatment apparatus of European Patent Application 1286382 comprises two opposing electrodes. The reactive gas supply and the surrounding inert gas supply are situated in the space between the two electrodes. The material to be processed passes under the electrodes and the mouth of both gas inlets.

A device for manufacturing printed circuit boards based on a laminate with a conductive copper layer by plasma generated by capillary discharge is the subject of US patent application 2002148816. This device is equipped with a plasma generator comprising a power supply and a first electrode with pins leading into a capillary array formed in a dielectric body. The workpiece to be processed is positioned between the aforementioned upper electrode and the lower grounded electrode.

SUMMARY OF THE INVENTION

These disadvantages and drawbacks of the prior art methods and apparatus for plasma treatment of surfaces are largely eliminated by the plasma treatment apparatus generated under normal pressure according to the invention.

SUMMARY OF THE INVENTION The device consists of a rigid frame for installation by connection to a grounded belt conveyor. Said apparatus envisages a belt conveyor with metal plates which can be used as a grounded electrode or a conveyor structure where a grounded plate (electrode) can be placed under the belt. A movable frame is slidably mounted on the rigid frame, to which is attached a conductive plate with spikes suspended in an inner cover of non-conductive material (dielectrics), wherein the inner cover hinge is equipped with a height suspension synchronization subsystem with spikes with profile height under the spikes .

The hinge of the inner housing can advantageously be designed such that it comprises a guide rod and a guide rod, respectively. guide rods and toothed rack slidable by the stepper hinge motor. This stepper hinge motor, together with the profile height sensor of the passing treated product, is connected to an external control of the rack height synchronization subsystem of the studs with the profile height below the studs of the passing treatment material.

Preferably, an outer cover is placed around the inner cover with the conductive plate with spikes and hinge rod, which shields the surrounding metal structure, thereby preventing discharge. This cover is hinged to the support frame so that there is a space of a few millimeters between it and the conveyor belt, except for the central part, where there is space for passing plasma treatment products. Furthermore, this cover has openings for the connection to the exhaust, which prevents the leakage of plasma-generated radicals outside the core of the technical solution. The outer cover also prevents ultraviolet radiation from entering the core.

The movable frame can be displaceably supported on the rails of the fixed frame, and the displacement of the movable frame on the fixed frame is preferably brought about by the threaded rod of the frame motor.

The benefit of the device according to the invention is that the inner plate (electrode) can perform linear vertical movement due to the movable suspension, thereby achieving a uniform surface treatment in irregular productions by raising or lowering the electrode according to the height of the treated surface. . The determination of the profile of the surface-treated body is ensured by a sensor placed in front of the entrance to the core - the space under the top plate.

In addition, the device is suspended on a frame which, due to the bearing on the rail, can be moved along the axis of the conveyor. The movement is accomplished by means of a stepper motor and a threaded rod. The motor is controlled to compensate for a too fast or slow passage of the treated product through the active zone of the device, or for the device itself to pass evenly over the treated body placed on a stationary conveyor in the event of discontinuous cyclic movement of the conveyor.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings illustrate the invention in greater detail:

FIG. 1 is a perspective view of a device according to the invention with a conveyor belt passing through; FIG. 2 is a perspective view of a device according to the invention;

DETAILED DESCRIPTION OF THE INVENTION

The device according to the invention in the exemplary embodiment (see Figs. 1 to 3) is provided with a metal plate with spikes, to which a high voltage provided by an external source (not shown) is applied to produce a corona discharge. The plate with spikes is suspended in the inner casing 2 of non-conductive material (dielectric), which insulates it from the rack Z with toothed rack 3 and a pair of guide rods 4. By means of the controlled stepper motor 5 the tip plate 1 from the surface to be treated (not shown) was constant. The treated material profile (not shown) is measured by means of the profile height measuring sensor 6 passing through the treated material, hung here above the core entry, which transmits information to an external control unit (not shown).

Around the inner housing 2 is an outer housing 7 of a non-conductive material which does not transmit UV radiation due to corona discharge. This outer cover 7 is provided with suction openings 8, which ensure the evacuation of the radicals formed outside the workplace.

The entire structure is mounted on a metal movable frame 9, which is provided with wheels 10. The frame 9 is slidably mounted on the rails 11 of the fixed frame 12. The threaded rod 12 permeates the movable frame 9, which is rotated by the controlled stepper motor 14 of the frame. This structure is intended for installation to a belt conveyor 15 which is provided with a grounding plate 16 or a belt conveyor under which the grounded plate 16 can be placed.

Industrial applicability

The device according to the invention can be used for the plasma treatment of both the continuously passing product and for the surface treatment of the product while the uniform treatment of the entire product is ensured by the passing device according to the invention.

Claims (6)

PATENT CLAIMS A high voltage plasma surface treatment apparatus for plasma treatment at normal pressure, characterized in that it comprises a fixed frame (12) for installation by connection to a belt conveyor (15) provided with a grounded plate (16), provided that on a fixed frame (12) 12) a movable frame (9) is slidably mounted, to which is connected a conductive plate (1) with spikes, suspended in the inner casing (2) of non-conductive material, the hinge (Z) of the inner casing (2) being equipped with suspension height synchronization subsystem prong plates (1) with a profile height below the prongs of the material being passed. Device according to claim 1, characterized in that the hinge (Z) of the inner housing (2) comprises a guide rod and a guide rod, respectively. a guide rod (4) and a toothed rack (3) slidably displaced from the hinge step motor (5), which hinge step motor (5) is coupled to an external height synchronization subsystem control unit together with a height measurement sensor (6) suspending the tip plate (1) with the profile height below the tips of the material being passed. Device according to claim 1, characterized in that an outer cover (7) is arranged around the inner cover (2) with the conductive plate (1) with the spikes and the rod (3, 4) of the hinge (Z). Device according to claim 1, characterized in that the outer cover (7) is provided with at least one suction opening (8). Device according to claim 1, characterized in that the movable frame (9) is slidably supported on the rails (11) of the fixed frame (12). Device according to claim 5, characterized in that the displacement of the movable frame (9) on the fixed frame (12) is exerted via the threaded rod (13) by the frame motor (14).