JP2020500729A - Apparatus and method for treating a surface - Google Patents

Abstract

An apparatus (1) for treating a surface with a jet comprising a plurality of particles, at least a mixing chamber (2) for mixing a propellant gas stream with the plurality of particles, generating a plurality of particles, A particle generator (8) designed to introduce a plurality of particles into the mixing chamber (2) in a solid state, comprising at least one screen plate (10); and a solid starting material (12). ), And a plurality of particles can be formed in a solid state by passing through a screen plate (10), and a particle generator (8) for introducing a propellant gas into the mixing chamber (2). An apparatus (1) comprising a propellant gas line (3) with a propellant gas nozzle (4) and an outlet (7) from a mixing chamber (2) for a propellant gas stream. With the indicated device and the indicated method for treating a surface, a particularly uniform and particularly intensive treatment of the surface can be achieved. In this case, it is possible to use particularly large carbon dioxide particles having a high kinetic energy, having a particularly uniform and particularly well controllable particle size. This applies in particular to the cleaning and removal of burrs or burrs. The device and method can be used in particular for the production of wire or plastic products. [Selection diagram] Fig. 1

Description

  The invention particularly relates to an apparatus and a method for treating a surface with a jet comprising a plurality of particles.

  In many situations, surfaces need to undergo mechanical cleaning. For example, in wire manufacturing, it may be necessary to clean the end product, for example to ensure product quality. Known solutions to do this use a variety of chemical and / or mechanical cleaning methods. For example, grinding, brush polishing, ultrasonic exposure or superheated steaming are contemplated. In particular, it is also known to treat the surface with a jet of carbon dioxide particles.

  These methods are also used in the manufacture of plastic products to remove burrs from the surface of the manufactured plastic product.

  Combinations of the mentioned methods are often used to achieve the desired results in each of the described applications. However, nevertheless, the results are often inadequate, not reproducible, too difficult to process, and consequently a limiting factor of the product quality and also of the production speed.

  Known methods in which carbon dioxide particles are used, in particular, have a non-constant and uncontrollable particle size and may not be able to achieve a uniform flow of particles. In particular, there may be pulsations in the flow of the particles. In particular, uniform cleaning or removal of burrs or burrs with reproducible results is not easily possible. In many cases, the method must be repeated several times for at least individual regions of the surface to be treated. It is also known that the kinetic energy of carbon dioxide particles is not sufficient. In that case, a larger particle size is desirable. Known solutions that attempt to achieve this in the prior art, but with particularly large particles, have the disadvantage that the particle sizes can vary widely. Furthermore, known solutions with particularly large particles are often susceptible to failure, especially in automated configurations.

  Based on this, it is an object of the present invention to at least partially overcome the technical problems described in connection with the prior art. In particular, it is intended to present an apparatus for the treatment of surfaces, which allows a particularly uniform and particularly intensive treatment of the surface. It is also intended to present a corresponding method.

  These objects are achieved by an apparatus and a method for treating a surface according to the features of the independent claims. Further advantageous refinements of the device and method are provided in the dependent claims respectively. Features described individually in the claims may be combined with one another in any desired technically meaningful manner, supplemented by explanatory material from this specification, and may further comprise features of the present invention. This shows a modification.

According to the present invention, there is provided an apparatus for treating a surface with a jet comprising a plurality of particles. This device, at least,
A mixing chamber for mixing the propellant gas stream with the plurality of particles;
A particle generator designed to generate a plurality of particles and to introduce the plurality of particles into a mixing chamber in a solid state, comprising at least one screen plate and pressing a solid starting material to screen A particle generator, wherein a plurality of particles can be formed in a solid state by passing through a plate;
A propellant gas line with a propellant gas nozzle for introducing the propellant gas into the mixing chamber;
An outlet from the mixing chamber for the propellant gas stream.

  The described apparatus is used, for example, in particular in the manufacture of wire and plastic products, but can also be used in other applications, in particular in the case of carbon dioxide jets in principle. With the described apparatus, for example, cleaning of the surface of a manufactured wire or a manufactured plastic product can be performed. Buds or burrs may also be removed from the surface of the manufactured wire or plastic article. Removal of burrs or burrs means that excess material is removed from the surface. Excess material may be formed as burrs or burrs, particularly where the parts of the casting mold are joined and / or where the casting mold is provided with an inlet for the casting material.

  The solid starting material from which the particles are formed is preferably a liquid or gaseous substance at room temperature. Especially when the substance is a gas at room temperature, the treatment of the surface can be carried out without residue of the substance remaining on the surface. The substance is preferably carbon dioxide.

  To generate a jet comprising a plurality of particles, a propellant gas stream is first provided. This can be performed, for example, by a compressor. The propellant gas stream is preferably a stream of compressed air. However, gases other than air, for example nitrogen or carbon dioxide, may also be used.

  The mixing chamber is a closed space except for the openings described. Said openings are especially openings and outlets of propellant gas nozzles. The propellant gas nozzle is preferably located on the side of the mixing chamber opposite the outlet.

  The suitability of the mixing chamber for mixing the propellant gas stream with the particles is such that the mixing chamber is configured to contain a plurality of particles after the propellant gas stream passes through the mixing chamber and is connected to a particle generator. Should be understood as meaning.

  The particle generator is preferably configured such that the solid starting material can be pressed onto the screen plate by a conveying screw or a pneumatic or mechanical press. For this purpose, the particle generator preferably has a particle generator chamber with an inlet, through which the starting material can be introduced. This can be done in the solid state by nature or alternatively in the liquid state. In the latter case, the particle generator chamber is preferably temperature controlled or cooled such that the starting material is converted to a solid state in the path from the inlet to the screen plate. The solid starting material can preferably be transported through the particle generator chamber by a conveying screw or a pneumatic or mechanical press. Preferably, the solid starting material is in a form that allows such transport through the particle generator chamber. This means, in particular, that the solid starting material need not be a solid block. The solid starting material may also be subdivided into a plurality of smaller parts. The solid starting material may, for example, take the form of compacted snow.

  Preferably, the particle generator chamber is configured concentrically around the propellant gas line. Furthermore, the screen plate is preferably of circular configuration, in particular provided with cutouts for propellant gas lines or propellant gas nozzles. Preferably, the notch is located at the center of the screen plate. The notch is preferably of circular configuration. A round propellant gas line or propellant gas nozzle in the center of the round screen plate allows to achieve a particularly uniform mixing of the particles and the propellant gas stream. In particular, a circular jet can be generated. Such a jet is preferred for most applications.

  Preferably, the screen plate has a plurality of openings. The opening of the screen plate is preferably of a circular configuration. The openings allow the solid starting material to be pressed through the screen plate, resulting in the formation of particles. The particles have a particle diameter that results from the opening diameter of the opening. Thus, the particle size can be controlled by selecting the opening diameter of the opening. The opening diameter of the opening of the screen plate is preferably in the range of 0.5 mm to 5 mm [millimeter], particularly in the range of 1 mm to 3 mm. The particle size can in particular also influence the mass of the particles, and thus the impact energy at which the particles strike the surface. The higher the impact energy, the greater the attrition that can be achieved. For example, in the case of light soiling and / or sensitive surfaces, such as, for example, plastic surfaces, an opening diameter of 0.5 mm to 2 mm [mm] is preferably selected. In the case of more severe soiling and / or less susceptible surfaces such as, for example, metal surfaces, an opening diameter of 1 mm to 5 mm [mm] is preferably chosen.

  Preferably, the device is configured so that the screen plate can be easily replaced. In that case, it is possible to adapt the particle size to the requirements of different applications by choosing from different screen plates. In some applications, a uniform particle size may be desired. In other applications, for example, it may be appropriate to simultaneously spray different sized particles onto the surface to be treated. Similarly, the opening diameters of all the openings can be equal or different in size.

  The generation of particles by the particle generator makes it possible to supply particularly large particles and mix them with the propellant gas stream. Thus, the particles can in particular be larger than those which can be formed, for example, by spraying liquid carbon dioxide. Larger particles can have a higher kinetic energy and therefore have a greater effect in treating the surface. For example, large particles can remove severe dirt on the surface. Allowing the generation of large particles of uniform size by means of the screen plate means that excellent and also uniform effects can be obtained with the described apparatus, and in particular reproducible cleaning performance can be achieved.

  The components of the device, and in particular of the device that can come into contact with the substance, in particular the solid starting material and / or the particles, are preferably formed of a material that can withstand the low temperatures expected when contact takes place. In the case of solid carbon dioxide, this temperature can be, for example, about -80 <0> C. Steel, particularly preferably high-grade steel, is preferred as material for the device.

  The propellant gas stream can be introduced into the mixing chamber through a propellant gas line, and the particles can be introduced into the mixing chamber through a screen plate. Preferably, the particles are introduced into the mixing chamber in the direction of the propellant gas flow. This allows the entire mixing chamber to be used to mix the propellant gas stream with the particles. The propellant gas stream mixed with the particles can exit the device through an outlet from the mixing chamber for the propellant gas stream. The outlet is preferably configured with a circular cross section. This enables a circular jet. In order to achieve the most uniform mixing of the particles with the propellant gas stream, the propellant gas nozzles, mixing chamber and outlet generate a flow that allows the particles to mix with the propellant gas stream by swirling. It is configured and arranged so that

  In a preferred embodiment of the device, the propellant gas nozzle is configured as a Laval nozzle.

  Laval nozzles are particularly suitable for uniformly mixing the propellant gas stream with the particles.

  In a further preferred embodiment of the device, at least the mixing chamber and the propellant gas nozzle are configured to be rotationally symmetric about the axis of the device.

  In this embodiment, it is possible in particular to generate a circular jet. This is advantageous in many applications as described further above.

  In a further preferred embodiment of the device, the particle generator further comprises a transport screw, the transport screw being designed to push the solid starting material through the screen plate.

  The transport screw is preferably configured to be able to transport the solid starting material from the entrance of the particle generator chamber to the screen plate. Furthermore, the solid starting material can be pushed through the screen plate by a conveying screw. Thus, the transport screw can perform two functions. In particular, the transport screw can generate particles continuously. Therefore, the apparatus can continuously generate a jet for treating a surface.

  In a further preferred embodiment of the device, the mixing chamber is configured as at least part of an external Laval nozzle.

  As further described above, the propellant gas nozzles, mixing chamber, and outlet are configured and arranged to generate a stream that allows the particles to mix with the propellant gas stream by swirling. Such a flow can be generated in particular in the manner of a Laval nozzle.

  In a further preferred embodiment of the device, the particles can be formed at least in part of solid carbon dioxide.

  Carbon dioxide has the advantage that it is converted into a gaseous state immediately after impacting the surface to be treated without leaving any residue.

  According to a further aspect of the present invention, there is provided a method for treating a surface with a jet comprising a plurality of particles, wherein the apparatus as described is used.

  Certain advantages and design features of the devices described further above are applicable and convertible to the described method, and vice versa.

  In a preferred embodiment of the method, the plurality of particles are generated by a solid starting material that is forced through a screen plate.

  In a further preferred embodiment of the method, the solid starting material comprises carbon dioxide, in particular carbon dioxide snow.

In a further preferred embodiment of the method, the treatment of the surface comprises:
Cleaning the surface;
-Removing burrs or burrs from the surface.

  The steps shown can be performed alternatively or cumulatively, i.e., the surface can only be cleaned, only burrs or burrs can be removed, or the surface can be cleaned and burrs or burrs removed. Both can be done.

  The invention and the technical environment are described in more detail below with reference to the figures. The figures show particularly preferred exemplary embodiments, but the invention is not limited thereto. In particular, it should be noted that the figures and particularly the relative sizes shown are only schematic.

1 schematically shows a cross-sectional view of an apparatus for treating a surface.

  FIG. 1 shows a cross-sectional view of an apparatus 1 for treating a surface with a jet comprising a plurality of particles. Apparatus 1 includes a mixing chamber 2 for mixing a propellant gas stream with a plurality of particles. The device 1 further comprises a particle generator 8, which is designed to generate a plurality of particles and introduce them into the mixing chamber 2 in the solid state. The particle generator 8 has a screen plate 10 and a transport screw 9. The plurality of particles can be formed in a solid state by pushing the solid starting material 12 by the conveying screw 9 and passing it through the screen plate 10. The particle generator 8 preferably has a particle generator chamber 14 with an inlet 13 through which the starting material or substances for producing the starting material can be introduced. In this case, the liquid carbon dioxide can, for example, be advanced into the particle generator chamber 14 through the inlet 13 and solid carbon dioxide and carbon dioxide gas will be formed in the particle generator chamber 14 as solid starting materials. .

  The device 1 further comprises a propellant gas line 3 comprising a propellant gas nozzle 4 configured as a Laval nozzle 5 serving to introduce a propellant gas into the mixing chamber 2. The device 1 also has an outlet 7 from the mixing chamber 2 for the propellant gas stream. The mixing chamber 2 is configured as a part of the external Laval nozzle 11.

  The mixing chamber 2 and the propellant gas nozzle 4 are configured to be rotationally symmetric about the axis 6 of the device 1. The outlet 7 has a round configuration.

  With the indicated device and the indicated method for treating a surface, a particularly uniform and particularly intensive treatment of the surface can be achieved. In this case, it is possible to use particularly large carbon dioxide particles having a high kinetic energy, having a particularly uniform and particularly well-controllable particle size. This applies in particular to the cleaning and removal of burrs or burrs. The apparatus and method can be used in particular for the production of wire or plastic products.

DESCRIPTION OF SYMBOLS 1 Apparatus 2 Mixing chamber 3 Propellant gas line 4 Propellant gas nozzle 5 Laval nozzle 6 Axis 7 Outlet 8 Particle generator 9 Conveyor screw 10 Screen plate 11 External Laval nozzle 12 Solid starting material 13 Inlet 14 Particle generator chamber

Claims (10)

An apparatus (1) for treating a surface with a jet comprising a plurality of particles, at least comprising:
A mixing chamber (2) for mixing a propellant gas stream with said plurality of particles;
A particle generator (8) designed to generate said plurality of particles and to introduce said plurality of particles into said mixing chamber (2) in a solid state, said at least one screen plate (10); A) wherein said plurality of particles can be formed in a solid state by pressing a solid starting material (12) through said screen plate (10);
A propellant gas line (3) comprising a propellant gas nozzle (4) for introducing the propellant gas into the mixing chamber (2);
An outlet (7) from said mixing chamber (2) for said propellant gas stream.   The device (1) according to claim 1, wherein the propellant gas nozzle (4) is configured as a Laval nozzle (5).   Device according to claim 1 or 2, wherein at least the mixing chamber (2) and the propellant gas nozzle (4) are configured to be rotationally symmetric about an axis (6) of the device (1). (1).   The particle generator (8) further comprises a transport screw (9), which is designed to push the solid starting material (12) through the screen plate (10). Apparatus (1) according to any of the preceding claims.   Apparatus (1) according to any of the preceding claims, wherein the mixing chamber (2) is configured as at least part of an external Laval nozzle (11).   The device (1) according to any of the preceding claims, wherein the particles are at least partially formable with solid carbon dioxide.   A method for treating a surface with a jet comprising a plurality of particles, wherein the device (1) according to any one of claims 1 to 6 is used.   The method of claim 7, wherein the plurality of particles are generated by a solid starting material (12) that is forced through a screen plate (10).   The method according to claim 7 or 8, wherein the solid starting material (12) comprises carbon dioxide. The treatment of the surface comprises:
-Cleaning the surface;
Removing at least one of burrs or burrs from the surface.

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