MXPA97001649A - Removal of particles of dust from a dematerial track with motion relat - Google Patents

Abstract

The procedure is based on the realization of dedusting devices. By means of the use of a gas or air stream, the corresponding flow energy can be applied directly on the surface of the material, which causes a discharge effect (according to Paschen's Law) and by means of a special profiling or a deviation of flow simultaneously causes a suction effect and with this a removal of the dust particles. For this, the entire dedusting device can be formed in a very compact manner, and the maintenance costs are reduced to an absolute minimum.

Description

REMOVAL OF DUST PARTICLES FROM A TRACK OF MATERIAL WITH RELATIVE MOVEMENT DESCRIPTION OF THE INVENTION The present invention relates to a method according to the main idea of claim 1 as well as to a device according to the main idea of claim 4. The construction of apparatus for removing dust for tracks of material in motion, also called track cleaning apparatuses can be roughly divided into contact free as well as those that work with a brushing support, in the last apparatuses the dust particles are mechanically released with rotating brush rollers or rows of brushes stationary material track, and then sucked. The kind of brushing as well as its material strength and shape are determined by the properties of the material surface to be cleaned. Such devices for dust removal not in accordance with the common are described in Bundesverband Druck e. V Postfach 1869 Biebricher Alie 79, D-6200 Wiesbaden 1 Technischer Informationdienst 11/1985, p. 1 to 20 as well as in patent WO87 / 06527. Apparatus for dust removal that work free of contact have a blowing unit, which sends a jet of gas on the track to be cleaned, as well as a suction unit, with which the gas that has been taken by the particle is sucked off. dust. With the blow unit REF: 24205 together or in the vicinity, discharge electrodes are arranged to discharge the dust particles that are on the material track. Such dusting apparatuses are known from European patents EP-A 0 245 526, EP-A 0520 145, EP-0 524 415, EP 0 395 864 and Swiss CH-A 649 725. Another way is described in FIG. EP-A 0084 633, a stream of turbulent gas is directed here on a fabric track to be dedusted and this is vibrated by the turbulent flow, whereby the dust particle of the material track is released or detached. . This type of de-polishing can only be applied on thin material tracks, which are allowed to be vibrated by the gas jet. A cleaning apparatus that does not belong to this type for the removal of a liquid on a moving band, especially a roller band having a liquid adhered thereto is described in DE-A 4 215602. In this case it is not solved the problem that occurs in a device for de-polishing the particles adhered to the surface by the electrostatic forces While the aforementioned dedusting apparatuses have a technical conformation of current at the outlet of the nozzle of the blowing units, they have they are constructed with channels of constant cross section suitable for the material track in the outlet opening of the nozzle, as for example in EP-A 0 245 526, EP-A 0520145 and DE-A 214 602. Only in the EP- A 0 084 633 and a variant embodiment of DE-A 4 215602 describes a cross section of the outlet channel with a variable cross section. In EP-A 084 633 the gas stream is directed perpendicularly to the tissue track. DE-A 4 215 602 uses a nozzle or nozzle falsely named Laval nozzle with a pear-shaped extension after a narrowing and which then narrows again in its cross section. The invention solves the problem of removing dust from a track of stable moving material that is not put into vibration, where it can be dispensed with using discharge electrodes. The invention is based on the surprising knowledge that only by the selection of a gas stream, especially its pressure, is it possible to effectively de-dust an area that has pressure of a track of material as well as the selection of the spacing of that area of a grounded surface. It has continued with knowledge, that an effective dedusting is only possible if the gas pressure of the gaseous current on the area that has pressure is so great, that the critical tension corresponding to the product of the gas pressure and the upper distance according to the Paschen's law is smaller than the electrostatic voltage (charge) of the powder particle, which preponderantly fixes the particle on the material surface. That is, under these relationships a self-discharge of the dust particle takes place, they are neutralized. Now they only adhere because of the small Van der Waal force and other non-electrostatic forces. The velocity of the gas stream that generates the conditions of Paschen's law will now be so high that it can also remove the weakly adhered powder particles. The discharge effect (Paschen's law) is supported by Bailo's electricity effect (cascade electricity, Lenard effect) as produced by the narrow nozzle section. Here at least partial ionization of the gas flowing through it is carried out, which in this case would be air, without the use of any electrical energy in the ionization unit. The second surprising knowledge that has been acquired is that by the special conformation of the suction unit the gaseous current is deflected at a certain angle and with this the suction effect necessary to bring the powder particle to the suction unit is achieved. Based on this knowledge, there is only a small selection here. With this disappear both the almost daily disassembly for cleaning the high voltage electrodes and the subsequent exact adjustment when reassembling, in devices constructed in accordance with the present invention. The driving gas stream is preferably achievable by the shaping of the blowing unit and / or the suction unit, as described in the appended claims. In the following, the method according to the invention as well as the devices that can be used to carry it out will be described in more detail by means of examples. In addition to the arrangement of nozzles described here and the corresponding constructions, other embodiments can also be used for the discharge of the powder particle as well as to overcome the arresting forces in the track of the material without the use of high voltage electrodes using electrical energy. . In the drawings shows: Fig. 1 a schematic representation of the forces, which stop a particle of dust on the material track. Fig 2 the law of Paschen Fig 3 a cross section through the dedusting device Fig 4a and 4b a partial cross section and a plan view in the direction IVb in a blower unit of the dedusting device with an output of slit-shaped gas Fig 5a and 5b a representation analogous to those of Figs 4a and 4b for a gas outlet arranged in a row of nozzles Fig 6 a cross-section through a variant of the dedusting device with two blowing units arranged on the same side of the surface of the material track Fig. 7 a cross section through another variant of the dedusting device, wherein the material that has been pressed is deflected Fig. 8 a cross section through the device shown in Fig 3, but with influencing elements on the blowing and suction units Fig 9 a plan view in the observation direction X in Fig 8 on the elements of influence on the flow for the blow unit Fig. 10 a plan view in the direction of observation X in figure 89 on the influence element for the suction unit Fig. 11 a longitudinal section through a variant of a blow and suction unit Fig. 12 a schematic representation of a dedusting device with the blow and suction unit shown in figure 11 to remove dust from sheet material. In Fig. 1, the electrostatic and Van-der-Waal forces E and W, which act on the dust particle S, are schematically represented. Often, the dust particles S, kept fixed by liquid bridges F. The gas stream G, which acts on the dust particle S, penetrates on the right side B, of Fig. 1. The gas stream G, is suctioned on the left side A. In Fig. 2, Paschen's law is presented, that is, the dependence of the critical tension U / crit, of the product of the pressure p, and the distance d, for different gases. Fig. 2 is a copy of drawing 6. 20, by K. Simonyi "Physikalische Elektronik" Verlag BG Teubner Stuttgart, 1972, page 526. The Law of Paschen among others, is described in this book on pages 524 to 526 , as well as in the book Physik Springer Verlag 1960, page 303, by Ch. Gertsen. By means of this law, the critical electric voltage U / crit is indicated, where a discharge between flat electrodes is ignited or produced, where p is the pressure of the gaseous current between the electrodes. The product pressure distance p. d. , is given on the abscissa d in Fig. 2, in Torr. cm. where 1 torr, is 133 Pa at 0 ° C. According to the invention, Paschen's law will now be used to dust off a track of material 1. The powder particle S, adheres due to its electric charge to the track. Now, according to the present invention, a blowing unit 3a / b, of the dedusting device with a potential surface grounded at a distance d, from the surface of the material track will be arranged and the speed and pressure will be adjusted between the material surface and the potential of the gas stream G, which rises above the sound velocity of the blowing unit 3, that the voltage caused by the charged dust particle S, is equal to the critical stress U / crit, in Paschen's law.

You can now look in Fig. 2, the product p. d. needed for the critical voltage U / crit. Now the pressure of the gas between the material surface carrying the powder particles 5, and the potential surface to ground is adjusted in such a way, that with the constructive distance d, predated between the material surface and the potential surface to ground, approach the value sought for the product p. d. With the help of an electronic field meter, the high electrical load can be determined.

In this way, the product p is brought to an optimal state. d. , in the assembly and adjustment of the dedusting device. The required conditions are allowed to reach with the gaseous current at a speed higher than that of sound, the particle of discharged powder S, is now taken by the gas stream G, without the use of discharge electrodes, with electric voltage and is suctioned with a suction unit 7, this eliminates the high maintenance costs needed for devices with electric discharge electrodes. The blowing unit as well as the suction unit, 3a / b, or 7a / b, respectively, are made of metal and grounded, therefore, the distance of the blowing unit 3a / b from the surface of the track of material 1, will be equal to distance d, from the potential ground surface, to that. To obtain a good electrical conductivity, the surfaces opposite the material track 1, belonging to the blowing unit and to the suction unit 3a / b, 7a / b, can be coated with an electrically conductive layer. With aluminum, for example, an anodization process would be used to obtain a good electrical conductivity. In the dedusting device shown in cross-section in Fig. 3, both a top and lower side dust removal, 9a, 9b, of the material track 1 is possible. For this, it is arranged both on the side upper as in the lower 9a, 9b, a corresponding blow unit 3a, 3b, and a suction unit 7a, 7b? the movement of the material track 1 is performed in the direction of the arrow 11, the transport speed of the material track 1 remains in the exemplary embodiment described between 4.75 and 15m / S, the transport speed, it has no influence on the degree of efficiency of the dedusting device. The blowing device described below 3a, 3b is constructed in such a way that a supersonic gas stream emerges therefrom, in this case, a supersonic air stream G, the gas stream G, leaving the device blown 3a / b, it hits against the surface of the track of material 1, under an angle alpha, from 20 to 100 ° preferably, between 30 and 55 °, against its direction of movement 11. The suction of the dust particles S, raised from the surface of the material, takes place in the direction of stream 25, of the gas G, flowing outward, under a first sigma angle, of between 20 and 70 *, preferably of approximately less than 45 °, and still becomes to connect to a second position approximately perpendicular to the surface of the material. This second suction acts especially on the dust particles S, which are in subsidence and holes. The blowing unit 3a / b has a partly branched nozzle structure described below. Starting from a pressure channel 13, as a gas supply unit, there is a cross section of nozzle 15, which narrows continuously, which after a narrowing 17, is transformed into a cross section 19, which is continuously widened to the exit of nozzle 20. The narrowing width 17, is between 0. 02mm and 0. 08mm; preferably somewhat less than 0. 04mm. The opening angle at the outlet of the nozzle 20 is between 3 and 15 *, preferably between 5 and 10 °; the generatrix line that remains to the left in the cross section of Fig. 13, in the cross section of the widening nozzle 19, is constructed in a domed manner, while the opposite generatrix line is a straight line 21. This line 21 runs under the angle alpha to the plane of the track of material 1.

The alpha angle is between 20 and 100 *, preferably between 30 and 55 °; the edge point 22, of that line 21, at the exit of nozzle 20, has the minimum distance d, to the track of material 1, between 0. 5 and 2 mm of the material that has pressure; this distance d, corresponds to the distance d, of the law of Paschen, the opening 23, between the two blowing units 3a, 3b, is constructed in the direction of movement 11, as a "V", which is enlarged in a manner triple, whose vertex angle increases in the stages of step 24a, 24b. The exit of the gas from the nozzle opening 20, takes place as indicated in Fig. 3, by an arrow , with inclination to the track of material 1, against its direction of movement 11, and in a suitable direction to find the suction unit 7a, 7b. The edge point 22, is constructed as a cutting edge; through this edge, at the outlet of the supersonic current G, from the outlet of the nozzle 20, a current swirl zone, whose turbulence supports a rise of the powder particle S, from the surface 9a, 9b, takes place. according to the law of Paschen, and against the force of Van-der-Waal W, the blowing units 3a, 3b, are made of metal and grounded by an electrical earth represented schematically analogous to the suction unit 7a, 7b. The nozzle outlet 20 remains in a plane 6, which cuts the material track 1, with an angle between 25 and 65 *, preferably less than 45 *. Similarly, to the two blowing units 3a, 3b, two suction units 7a, 7b are also provided; the two suction units 7a, 7b are positioned and constructed symmetrically with each other. Each of the two suction units 7a, 7b, has two suction channels 27 and 29, which open into a suction chamber 30, the inlets of the suction channels 31, 31b, are arranged in a plane 33, the which has a constant distance from the upper, lower side 9a, 9b, of the material track 1. The plane 33 is simultaneously the upper side of the suction unit 7a, 7b, which opposes the lower or upper side of the material . Preferably, the suction units 7a, 7b are made of an electrically conductive (metal) material. If another material or metal is used over time, it will be covered with a layer of non-conductive corrosion, then this surface like those of the blowing units 3a, 3b, as indicated above, will be covered with an electrically conductive layer. The plane 33 is as shown in FIG. 3, retracted with respect to the outlet of the nozzle 20; this recoil may be smaller, the plane 33 may also be arranged directly connected to the outlet 20 of the nozzle. The suction channel 27 has a suction mouth 35, inclined against the surface of the track of material 1, which narrows into a funnel; the inclination of the suction mouth 35, is directed towards the outlet 20, of the nozzle, the generatrix line 36a, of the suction mouth 35, funnel-shaped directed or opposite the outlet of nozzle 20, presents a beta angle as flat as possible with respect to the surface of the track of material 1; the beta angle is between 15 and 30 °. The other generating line 36b, from the suction mouth 35, opposite the generating line 36a, runs steeper and has a sigma angle between 20 and 70 ° with respect to the surface of the track of material 1. Since in each case, the suction mouth 35 must be constructed as a funnel, it avoids by itself that the beta and sigma angles have both extreme values of 30 °. The suction mouth 35, is transformed into a piece of channel 37, of which a generating line, is the extension of the generating line 36b; this piece of channel 37, expands to another piece of channel 39, which opens into suction chamber 30.

The distance h, of the cutoff point of the generatrix 36b, with the plane 33, from edge 22, (= a lower end of line 21), is ten to twenty-five times the distance d. By the arrangement of the blowing unit 3a, 3b, the suction channel 27, of dust particles S, which would eventually have adhered, is cleaned. The suction channel 29 is likewise constructed in the form of a funnel, where, however, its generating line 40a runs perpendicularly to the surface of the material track 1, while the opposite generating line 40b is slightly inclined with respect to the surface of the material track 1. The suction chamber 30m each time presents at an opposite wall at least one profiling 44, this profiling serves to hang current conducting sheets (not shown). The current-conducting sheets are necessary so that in the suction chamber 30, as much as possible in all the mouths of the channels 27 and 29, approximately equal pressure proportions prevail. To dust the material track 1, which moves with a speed of up to 30m / s, air G is blown from the blowing unit 3a, 3b, with an air velocity of up to a maximum of 550m / s. , to reach this current speed prevails in the pressure channel 13, an approximate pressure of 2bar. On the track of material 1, a pressure is produced according to the gas velocity above the selected sound of 50 to 100 mm.; the powder particles S, which are on the surface of the track of material 1, are now neutralized by the laws described by Paschen, in a dark discharge, which in principle is a discharge of effluvia with small current intensities, simultaneously a rise of the dust particles S takes place, by the supersonic current G, supported by the eddy caused by the edge 22, against the forces acting on them of Van-der-Waals. The dust particles S, are sucked by the suction channels 27, 29, where the channel 29, which runs almost perpendicular to the surface of the track of material 1, has the main role, to remove the dust particles S, from the sinking of holes. The air blown through the blowing unit or blowing units 3a, 3b, as well as the suction power of the suction units 7a, 7b, is in the temperature range between 18 to 23 °, in the space in which the dedusting device is overpressure prevails. The nozzle outlet 20, as well as the entrances to channels 27 and 29, as shown in Figs. 4a, 4b, with increase in cross section and in plan view respectively, may be constructed as longitudinal slots 41, and as rows of nozzles 43, as shown in Figs. 5a, 5b. In order to improve the capture process of the powder particles S, in the supersonic gas stream G, they can be arranged in the widened cross-section of nozzle 19, of the blowing unit 3a, 3b, as well as in the two suction channels 27 and 29, elements that influence the stream 49, 50 and 51, as indicated in Fig. 8.

In the current influencing elements arranged in the nozzle area 19, next to the wall 21, and indicated by the figure 49, these are narrow longitudinal rods as shown in a plan view in the direction of observation IX, in Fig. 9, each longitudinal rod 49, lies in a plane running parallel to the direction of movement 11, plane having an angle of 82 °, with respect to the track of material 1. In the example described above, they have the longitudinal rods 49, a width of lmm, and a distance between the opposite sides of 15mm. In the rows of rods 50 and 51, disposed in the suction channels 27 and 29, these are narrow longitudinal rods as shown in a plan view in the direction of observation X, in Fig. 10. Each longitudinal rod 50 and 51, is in a plane that also runs parallel to the direction of movement 11, which runs under an angle of 60 *, with respect to the track of material 1. In the example described above, have the longitudinal rods 50, 51 , a width of 2mm, and a distance between the opposite sides of 30mm. Additionally, to the blowing units 3a and 3b, shown in Fig. 3, there can also be arranged on both sides of the suction unit 7a, 7b, another blowing unit as shown in Fig. 6. Instead of tracks of flat material 1, can also be replaced by a deflection unit 45, tracks of twisted material; the position of the blowing unit, as well as that of the suction unit, will then, as shown in FIG. 7, be adjusted to the course of the material track 46; the detachment angle of the material track 46, of the diverter unit 45, is preferably between 15 and 20 °, so as not to unnecessarily increase an electric load by load exchange and load separation. The aforementioned division in two of the blower unit 3a, 3b, with the partial pieces 3 'and 3", allows an easy manufacturing compared to a one-piece manufacture, the division is carried out along the line 47, which becomes the line 19. The sealing takes place by a sealing ring 48, whose course is determined by the use of the nozzle row 43, or the longitudinal slot 41, only by the division of the blow unit 3a, 3b, simple fabrication of the elements 49 influencing the flow is possible The blowing unit 3a, 3b, as well as the corresponding suction units 7a, 7b, are preferably made as blocks, which can be install next to each other in a row parallel to the movement of the material track, in order to be able to adjust the width of the dedusting device to the corresponding width of the material track. e material, you can also move the dedusting device over the material track; but as a rule, it is preferred that the material track passes down or between the inlets and outlets of the nozzle. With the dedusting device described above, not only tracks of material can be dedusted, but also plates and arcs. The dedusting device described above, can be used to dust all kinds of material in the form of a plate track, such as pressed chip plates, plates for tables, bands, made of synthetic material, paper, cardboard, glass, sheets as general, metallic and medicinal sheets, textiles, conductive plates, industrial meshes, film strips and magnetic. Instead of the blow unit 3a, 3b, shown in Figs. 3 to 10, a unit 53, shown in Fig. 11, which represents a composition of a blow unit with a suction unit, can also be used, in addition, here work in the area below and the speed of sound on the contrary that in the blowing units 3a, 3b, with respect to the gaseous output stream; however, it is also possible to work in the supersonic zone, analogously to the blowing units 3a, 3b, also the unit 53, it is constructed of two parts of nozzle 54a, 54b, grounded and has a narrowing 55, in the section cross section 56, of the nozzle channel. Starting from a pressure channel 57, constructed analogously to the pressure channel 13, this nozzle also has a cross section 59, which narrows (analogous to 15). In contrast to the blowing units 3a, 3b, the narrowing 55, which has the straight generating lines, is continued until the exit 60, of the nozzle, and with this, is significantly longer. That is, here a stronger ionization effect (Bailo electricity) takes place, on the gaseous stream flowing therethrough, the narrowing axis 55, has a preferred delta angle, of about 51 °, with the tangent 68, a the material surface 71, other values for the delta angle between 20 and 100 °, and especially between 30 and 55 °; however, the value indicated in the exemplary embodiment allows optimum work, especially if a low air flow and a good pressure is considered on the material track 71, which has pressure on the drum 74, (pressure cylinder). Also this unit 53 has, analogously to the blowing units 3a, 3b, a nozzle cross section that expands in a technical manner for the current that now forms the space 61, before the outlet of the nozzle 60. In contrast to the blowing units 3a, 3b, the edge 63, is here constructed analogously to the lower edge 22, opposite one side of the nozzle channel and the other with a height of edge a, from 0. lmm to 0. 9mm, that is to say prolonged outward 0. 6mm. This prolongation causes, on the one hand, a widening of the nozzle channel, and on the other, a deviation of the gaseous stream that exits, as indicated by the arrow 64; with this, the gaseous current causes a suction effect which forces the dust particles to the unit 65, which finally takes care by means of an ordered series of rods in the suction channel, the direction of the current and finally, a important role for the drive of dust particles to the suction hose. The width b, of the narrowing 55, is adjusted together with the gas pressure in the pressure channel 57, in such a way that optimum dedusting takes place with the minimum possible air flow. In the variant embodiment described herein, preference is given to a narrowing width of 0. 04mm, at a pressure of 1.5bar, in the pressure channel 57, and a distance d / 53 of 4m to 7mm, preferably 5mm. The inclination of the narrow nozzle channel 55, with respect to the tangent 68, to the material track 61, is here of for example 51 °. The suction unit integrated in the unit 53, consists of a suction channel 65, constructed analogously to the suction channel 35, 37, 39, where here in a simplified construction embodiment, a wall of the channel is formed by a sheet 67, modeled Correspondingly, the suction channel inlet 65 also presents, in a manner analogous to that described above, an acute angle fi, in the conveying direction 70, of the material track. The angle fi, must have a value between 20 and 50 °, and preferably between 33 and 39 °. The edge opposite the outlet 60, of the nozzle and belonging to the inlet opening of the suction channel, is at a distance e, which in this example of embodiment measures 17mm. In order to minimize the air consumption required for dedusting, the pressure channel 57 is subdivided, in the direction transverse to the track of material 71, into individual partial channels. These partial channels are not explicitly represented, which in Figs. 11 and 12, are identified with the figure 57, are connected each time through a supply channel that closes by a plunger that is not represented by a supply chamber 69. To perform a pressure equalization, they present the supply channels, cross sections of current that vary very slightly, the pistons are adjustable through a mechanism not shown starting from the outer periphery a supply channel is separable after the other, and with this also a partial channel after the other, the supply of air, and with this, the supply chamber 69. This makes possible an adjustment to the width of the track that really should be cleaned. In this way, only a necessary number of partial channels are fed with pressurized air, and with this, the air expenditure is optimized by making it at a minimum. The arrangement of the blow / suction unit 53, in a dedusting device for material 71, in sheet form, is shown in Fig. 12, the leaves 71, which are to be cleaned, put on and fixed with a handle 72, on a first drum 73 (supply cylinder), the passage to a second drum 74 (pressure cylinder), takes place in an approach position 76, with neighboring handles 72, 75, where the handle 72 is opened synchronously, and closes the handle 75, in the arc socket. The representation in Fig. 12, shows the material 71, already grasped by the handle 75, with the handle 72, open, where a part of the material 71, in sheet form, still rests on the drum 73, while pull this To the drum 74, the blow / suction unit 53 is coordinated, to which in the direction transverse to the width of the material 71, safety rollers 77 are arranged, which ensure a guide of the sheet material in form 71, to a fall of the air stream, or also ensure a problem-free sheet transmission.

Due to the high speeds of rotation used in the drums 73, 74, the bows 71 (made of material) tend to detach from the surface of the drum, with the device or devices according to the invention, it is allowed to adjust by the pressure of air this lifting, together with the dedusting satisfactorily, however, if the air pressure is adjusted in such a way, that only a dust removal is achieved without problems, it may be too low for the fixing of the arcs, in this case the security rollers 77 will take the paper to stop the arches in a low position. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the present invention as above, the content of the following is claimed as property:

Claims (13)

1. REVINDIC ACTIONS 1. - Procedure for the removal of dust particles of a track surface of especially stable material that move relative to each other, with a dedusting device that works free of contact, a method characterized in that a potential flat region of a blow unit opposite the surface of the track of material and ground, and belonging to the dedusting device, is at a certain distance from the surface of the track of material, the speed and pressure between a surface area of the track of material to be pressurized and the potential surface of the gaseous stream leaving the blow unit, are adjusted in such a way that the product of the pressure and distance, according to the law of Paschen, which corresponds to the critical tension is below the electrostatic tension of the powder particle on the surface of the material track, thereby neutralizing it In this way, the expiration of the forces of retention of dust particles on the surface of the material track, and dust particles without an ionization unit that uses electrical energy, will be captured by the gaseous current and suctioned. by at least one suction unit.
2. 2. Method according to claim 1, characterized in that the gas stream, especially a stream of air, is blown at an angle K »cD between 20 and 100 °, preferably between 30 and 55 ° on the surface of the material track. and suctioned by means of at least one suction unit connected against the gas current direction, that is, in the direction of material transport.
3. 3. -Procedure in accordance with the claim 2, characterized in that the powder particle lifted by the gas stream from the surface of the material track is taken by a first suction opening inclined at an angle. { (T fF) between 20 and 70 °, preferably 45s, with respect to the current direction, as well as preferably by a second additional suction opening which is approximately perpendicular to the track surface of the material.
4. 4. - Dust removal device for carrying out the method according to one of claims 1 to 3, provided with a blowing unit attached to a supply unit as well as a suction unit, characterized in that the blowing unit starting from the supply unit of the fluid to be blown has a narrow cross section, which after a narrowing is transformed in a widened cross-section, the blowing unit has an electrically conductive, earthed surface area, opposite to the track surface area of material carrying the powder particle, where it was pressurized by gas in the supply unit as well as the distance of the grounded surface area from the surface area of the material track are adjustable in such a way that the dust particle is detached, without having to use an ionizing unit connected to a source of electrical energy for iononization of the gas stream, and is sucked by the suction unit.
5. 5. - Device according to claim 4, characterized in that, the gas pressure in the supply unit, the distance of the potential surface earthed with respect to the surface area of the material track as well as the conformation of the cross section of the nozzle and its arrangement in relation to the region that must pressure are adjusted in such a way, that the critical voltage or critical voltage of Paschen's law depending on the product of the distance and a second pressure of gas generated with the blower unit from the gas pressure in the supply unit and that occurs between the earthed surface area and the surface area of track material that has pressure, is below the electrostatic voltage that stops in the area the particle of dust.
6. 6. Device according to claim 4 or 5, characterized in that the outlet of the nozzle is arranged in such a way that the gas stream that falls off hits the material track in the opposite direction to the transport direction.
7. 7. Device according to one of claims 4 to 6, characterized in that the axis of the nozzle channel of the blowing unit lies in a plane that is with respect to the material track or its tangents at an angle between 20 and 20. and 100 °, especially between 30 and 55 °.
8. 8. - Device according to the claim 7, characterized in that, the wall of the nozzle of the blowing unit has a wall area constructed asymmetrically to its axis, especially in the area of the opening, where one of the generating lines of the nozzle channel of the blowing unit is a straight line, which remains in a plane that runs with respect to the material track with an angle (oCßT) between 20 and 100 », preferably between 30 and 55».
9. 9. - Device according to the claim 8, characterized in that the generating line of the straight nozzle channel ends at the outlet of the nozzle at a cutting edge, to produce a current swirl zone that starts there from the surface of the material track.
10. 10. Device according to one of claims 4 to 9. characterized in that the suction mouth of the suction unit is narrowed starting from the funnel-shaped suction opening, where one of the generating lines is a first straight line, which runs in a plane that remains at an angle (ß, jfc) of 15 to 50a especially between 33 and 39 ° with respect to the material track.
11. 11. Device according to one of claims 4 to 10, characterized in that the blowing unit consists of at least two partial pieces and preferably the line or separating lines pass through the line of the generating line of the nozzle channel.
12. 12. - Device according to one of claims 4 to 11, characterized in that by means of a division into blocks preferably parallel to the direction of relative movement of the material track, the width of the device can be adjusted in a simple manner. width of the material track.
13. 13. - Device according to one of claims 4 to 12, characterized in that a first and a second blower unit disposed spaced apart in the direction of relative movement of the material track, which are on both sides of the suction unit, and preferably the axes of the channels of the blowing nozzles of the first unit and of the second blowing unit are directed against each other.