FIELD PARTICULATE PRODUCTION SYSTEM AND PROCESS FIELD OF THE ART The present invention relates to systems and processes for the production of fluidized particles for the production of fluidized particles and is particularly useful but not exclusive for the production of fluidized particles of ice. for application of ice jets. PREVIOUS TECHNIQUE Several systems have been created to carry out one or more functions of ice formation and removal, and ice particle formation and transport. The removal or harvest of ice from ice-making surfaces of ice-making units has been carried out by several methods, including melting, the use of gravity, scrapers, and other mechanical means or a combination of the above means, some of which are described in US Pat. Nos. 2,344,922? 2,995,017; 4,389,820; 4,707,951 and 4,965.96e. The formation of ice particles has been carried out by scraping or harvesting (US Pat. No. 2,344,922) or other methods involving grinding or crushing. Mechanical feeding technologies, by gravity or induction, have been used to facilitate the transport of ice particles in US Patents Nos. 4,707,951; 4,389,820; 2,995,017; 2,344,922; 4,965,968 and 2,724,949. "Pressure cooker" systems or b 10 batch atmospheric pressure = > Are they known and used for relatively non-degradable media where a prefabricated medium is batch-loaded in a holding vessel for subsequent treatment with, for example, particle grit, agitation and transport supply *? Such systems may be simplified and improved in terms of capital and operating costs and complexity through continuous systems or icon i nuo. There are inherent problems in continuous partially sealed systems, especially those used for particle transport and jet treatment. This system uses a means of air purge or another, as for example gave! gone carbon, in order to avoid the penetration of moisture and heat, and to minimize the formation of ice, agglomeration and problems of fluidity. It is also desired to be able to quickly suspend and quickly start systems between continuous operations. Such a purge, with the costs of operation, production and capital related, is one of the most expensive elements of the system. Without a total effective seal, its practical use causes waste. You can reduce costs by minimizing the volume required and optimizing its use.
The prior art systems try to isolate the production of particles from the treatment comprising the conditioning, including caliper, cooling and drying, and also the transport of the particles. This requires expensive and complicated equipment and a delicate balance of control between process unit operations. The present invention can be employed immediately in systems employing nozzles employing inductive suction for transport and / or jet effect. In such systems, a flow of purge medium to effect fluid transport of the particle is one of the most important factors in an inductor-type nozzle for transporting and achieving jetting. Therefore, the control and quantity of the purge medium are not only necessary aspects to correct the efficient processing, treatment and transport of the particles, but also the operation of correction of the inductive nozzle for the transport and operation of a final nozzle for the jet effect. Continuous prior art systems compared in the present invention are usually employed under partial environmental pressure conditions or are totally unsealed and as a result suffer from inefficiency and high equipment costs and a skilled workforce is required, said costs are caused by the agglomeration and clogging that arise from the penetration of moisture and the pressure imbalance of the system, which requires a delicate adjustment to correct the pressure of the system and the imbalance of flow. In practice, mechanical equipment that requires high energy consumption and important labor force such as sealing arrangements, airbags, vibrators, pumps and alpha radiators were used to correct these deficiencies, but In the case of efforts to seal part of the system in order to increase the efficiency of the system, such attempts created only greater complexity and higher cost. Therefore, the need for a simplified system that can reduce the mechanical, capital and operational costs, conserves the integrity of the solids by means of the integration of the production, calibra- tion and fi lydi fication of isolated particles. The prior art systems employing a positive pressure have been limited to subsystems partially sealed or individually sealed or batch operation, agitation, clogging prevention or short-distance fluidification in accordance with that illustrated in the North American Patents gray nos. 4,048,757 and 5,071, 289. PRESENTATION OF THE INVENTION In accordance with the present invention, a fluidized particle production system has a solidification unit with a solidification surface for supporting a solidified layer of a medium sol id idica / a traction apparatus to remove the solidified medium from the solidification surface and to calibrate the solidified medium stirred into particles of desired dimensions. The treatment apparatus comprises a calibrating device that cooperates with the solidification surface to achieve the calibration of the particles. Adjacent portions of the solidification surface and the gauging device are placed together in such a manner that the particles are formed without grinding the solidifying medium. A box, preferably sealed, encloses the solidification unit and the treatment apparatus and has an outlet duct communicating with the internal part of the channel, and at least one flushing fluid outlet positioned to discharge a fluid flow. in the boxes preferably in the vicinity of the calibrating device to fluidize the particles and transport the fluidized particles through the outlet duct. A source of sweep fluid supply is connected to the outlet and a valve between the source and outlet controls the pressure and fluid flow at the outlet. The present invention can be used to create particles made from solids, such as water, additives (solids or liquids), oryanic solvents, plastics and other materials that can be solidified into a friable, manageable form. Once produced, the particles can be adequately cooled or cooled ad libitum and fluidized in the flushing fluid which can be either a gaseous or a liquid medium, to produce a finished particle that flows freely from a liquid. suitable size for either ba ba or environmental pressure or under high pressure and also application of jets on a surface. The present invention is useful for operating together with transport ducts, pressure boosting accelerators (in the case of long distance or pneumatic transport pressure resistance) and discharge jet heads (in the case of cleaning and treatment). with jet). Preferably but not necessarily, the pressure boosting accelerators and the discharge jet forming heads employ an effective nozzle, in accordance with my copending application Serial No. 08 / 203,584, filed on 1 March of 1 *? 94. whose presentation is incorporated herein by reference. In such a nozzle a nozzle for forming jets is placed inside a main nozzle box through which the medium is supplied in the form of a high pressure jet to a main duct of the main nozzle head. As a result of the decompression of the jetting jet at high pressure after discharge of the jetting nozzle, a tapered flow front is formed in a construction nozzle throat of a discharge end of a nozzle box and forms a powerful effective nozzle. This effective nozzle arrangement not only provides a better and more controllable induction as well as a better energy transfer to accelerate the particles, but it also provides a device to further fracture and calibrate the transported particles for better acceleration. The system in accordance with the present invention is useful for increasing the performance of jet formation in jet cleaning systems employing inductive tuplet nozzles that are limited to an inductive vacuum for particle transport and are sensitive to imbalances, either in stops or starts, or in continuous operation, and also in heads of formation of discharge jet that employ such effective nozzles. The solidification unit can produce friable solids and, in the case of particulate ice, it can take the form of a conventional ice-making unit. As regards other friable solids, the invention can be used with another known apparatus that creates so-called particles, for example, moving strip surfaces, spray and instant dryers as well as cleaning columns. Regarding particulate ice, with the appropriate settings, the treatment unit can work in combination with several types of conventional ice manufacturing units, including horizontal drum, vertical drum and disc type ice making units. In a horizontal drum ice making unit, it is a variable speed or rotating drum having a forming or solidifying surface on which water is frozen. Water can be applied to the drum by spraying or flooding, or the drum can be partially immersed in water. Preferably, with the horizontal drum configuration, the water is first applied at a distance, in the direction of rotation of the drum, from the point where the ice is harvested. This allows an adequate pre-fogging of the drum surface and an adequate period to efficiently freeze the water. As the drum rotates, the water forms a solidified layer of ice. Additionally, water can be applied later in the rotation cycle to increase the thickness of the ice sheet. However, an area prior to the treatment apparatus is preferably reserved for subsequent cooling after solidification to increase the friability and ease of handling of the ice. The circumferential lengths of these zones depend on the conditions required to manufacture an adequately friable ice. In the case of water ice used for jet cleaning, the subsequent cooling zone facilitates the production of hard clear friable ice instead of the "normal" wet ice, and the best use of the sweeping fluid. Similarly, for other solids, singular or combined solids, to obtain hardness and friability by cooling, evaporation or curing, the same requirements are applied. Alternatively, a prior art apparatus comprising a vertical drum ice manufacturing facility or one of rotating discs (not illustrated) can be used, water is applied to the surface of a motor-driven drum. , on disc surfaces or on the internal surface of a drum, depending on the case. While the use of the horizontal drum is preferred because of its geometrical arrangement and space-saving feature, it will be apparent to one in the art that any other type of solidification unit or ice preparation may be employed in the present invention. In the case, particularly, of the horizontal rotating drum or of the disc type ice making unit, the application of the water can be affected by the partial immersion of the solidification or formation. However, for stopping and starting purposes it is preferred that the water be applied by means of multiple sprays. These have the advantage of a more practical control of the thickness and hardness of the ice layers positioning and applying the ice at one or several points of application. Such an application also means control and facilitates start-up conditions, par- ticularly when idle or off-line system conditions are required for practical operation. In a preferred method, for simplicity and flexibility when the process is stopped and started, the dryness and cold level of a sealed system incorporating the present apparatus can be maintained without keeping the sun medium idifiable in an immersion sump, maintaining a at operating temperature and controlling the application of the material to be solidified. The thermal tracing of the distribution lines and, if necessary, a renthole can be easily effected by techniques known in the art for environmental pressure or high pressure conditions. The treatment unit is indicated near the solidification unit, both are contained within the sealed box. If operated under high pressure, the frame can be of a common pressure vessel design and can allow practical access and overpressure protection. S-i can install seals and seals to avoid pressure loss and also leakage of air and moisture in the box. The box is effectively sealed to facilitate a high production rate of ice that has a high quality of clarity, hardness and friability and to allow efficient use of sweeping air. High quality cold dry air can be used for sweeping air and underpressure conditions can be used to increase the performance of a pressure boosting accelerator or b in a discharge jet head. The treatment unit preferably comprises a scaler, a calibrator and a sweeping medium distribution manifold. The gauge is positioned after the harvester in the direction of movement of the solidification surface. The profile of the gauge surface may comprise several regularly spaced teeth, of varying patterns, designed to produce particles of a desired uniform size, and may also include a profile suitable for harvesting the ice, in which case the harvester may be omitted. The fluid removal by means of the sweeping fluid helps to keep the calibrator free and to transport the particles. The fluidized medium may be the same as the scavenging medium as a gas for a pneumatic operation or a liquid such as a liquefied gas or a combination of both. Any of the means or both means can also be used to control the transport flow and the pressure of the enclosure for improved transport performance and the effect of jet formation in accordance with that described above, particularly when employed with a nozzle effective type. The harvester may have the shape of a fixed blade that may have teeth, a rotating roller, which may be helical in order to fracture or scrape the solid medium from the solidifying surface. The harvester may either be articulated or it may rotate freely or it may be coordinated with the solidification surface, but it will nevertheless be placed in contact with the solidified medium but not with the solidification surface. The main function of the harvester is to fracture the solidified layer into large blocks or flakes for a subsequent calibration. The calibrator may be in the form of a roll gauge having a profiled surface that fractures and releases a friable material from the solidification surface.
For simplicity and a better transport effect it has been found that the calibration device can be a calibration roller positioned near the solidification surface in motion of the solidification unit in such a way that a double roller-like assembly is created. In this case, the calibration roller is profiled with spaced teeth or it has either a propeller or b in another profile or a combination similar to the combination of a conventional combine. The roller can? to be activated by gears, a chain and cogwheel or other usual device, or it may be activated by the rotation of the solidification surface in such a way that its rotation corresponds to the surface of soli ification. The orientation and position of the calibration roller will depend on the type of solidification unit used. However, the calibration roller will be placed with a small clearance in relation to the solidification surface and positioned so that it is in contact with the solidified layer and penetrates the full width of the solidified layer to fracture and release the layer. solidified. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be apparent from the following description of modalities thereof with reference to the attached drawings, wherein:
Figure 1 shows a partially open perspective view of a sealed box having a solidification unit, an apparatus and treatment and associated components, according to the first embodiment of the present invention; Figure 2 shows a cross-sectional view through the apparatus of Figure 1; Figure 3 shows a block diagram of a system *? production of ice particles and ice jets incorporating the apparatus of Figures 1 and 2; Figure 4 shows an open cross-sectional view through parts of a modification of the apparatus of Figures 1 and 2, and Figure 5 shows an open perspective view of parts of the apparatus of Figure 4. DESCRIPTION OF THE PREFERRED MODALITY As shown in Figure 1, a separate box indicated generally by the reference number 10 has a pore i ón c 11 i ndri 9 and an extension l l l 11 that c omuni • "a a duct downwardly convergent outlet 12. The box 10 contains a solidification unit in the form of a horizontal ice drum generally indicated by the reference number 14, whose part mlrfrna communicates through a duct 16 with a light refill unit. ion 18 (FIG. 3) for cooling a solidification surface 20 or formation on the outside of the drum 14. As shown in FIG. 2, the channel 10 is provided with a drain opening 22 in the bottom , that opening connects by means of a drain tube 24 to a water reservoir 62 (FIG. 3) to recirculate the water from the drum 14. An electric motor 26 which connects through a reduction gear 28 to the drum 14 for rotating the drum 14 around its horizontal ee. Water supply pipes 30 and 32 are connected to perforated spray pipes 34 and 36 which extend parallel to the drum 14 and which serve to sprinkle water on the surface 20 in order to rear a layer (not shown) of water. ice on the surface of the drum 14 as the drum 14 rotates in the direction of the arrow A of figure 2. The lateral extension 11 of the channel 10 has an upper surface open upwards closed in a sealed manner by a cover 38 screwed on the box 10 and the crossover 10 and can be easily removed to provide a comfortable access to the inner part of the ca 10. Within the ca 10, a first roller in the form of helical harvester roll 40 is spaced from the surface of the drum 20 by a gap 41 that efficiently forms a narrow zone between the harvester roll 40 and the drum surface 20.
The harvester roll 40 is followed, in 1 to s > rotation of the drum 14, by a caliper roller 42 [mu] m. = > e extends also parallel to the drum 40 and forming in its external part, in a known manner, a plurality of spaced projections 44 and diessioned to produce, in cooperation with the drum surface 20, ice particles of desired dimensions. Further from the roll of the gauge 42 in the direction of rotation of the drum 14, a blade 48 fixed by means of screws 50 on the box extension 9 lies in the vicinity of the drum surface 20 in a location that follows almost immediately the caliper roller 42. A first air outlet in the form of an air discharge manifold 50 is run parallel to the rollers 40 and 42 and is located near the rollers 40 and 42 to direct a sweeping ie discharge. on the roller 42 v between the rollers 40 v 42, in accordance with that indicated by the arrow B, towards the outlet duct 12. A second outlet of air in the form of an air discharge manifold 52 is: parallel to the manifold 50 and is provided directly above the outlet duct 12 to direct the flow of air in the direction of the arrow C to the outlet duct 12. The spray pipe 34 is placed near under the knife 48 for download water on the s drum surface 2? A further solidification of this water to form a frozen layer of ice (not shown) on the surface of the drum 20 is then carried out in an area defined by the arc A 1 extending from the pipe 34 to the pipeline 36. It should be understood that, while the water is solidified by freezing in the present embodiment of the invention, different means may be solidified by another different way such as, for example, by curing or evaporation. The water is then sprayed by the pipe 36 on the drum surface 20, and the final solidification of the ice layer is then carried out on an area defined by a second arc A 2 from the pipe 36 towards the backlash 41. In the clearance 41, the harvester roll 40, in cooperation with the drum surface 20, fractures the ice sheet into ice flakes. These ice flakes are crushed between the gauge roll 42 and the drum surface 20 such that ice particles of the desired size are formed. The caliper roller 42 and the drum 14 consequently act as a pair of counter-rotating rollers forming between them a narrow groove in which the ice particles are formed. More particularly, the caliper roller 42 is driven by the motor 26 and the speed reduction gear in timed relationship with the rotation of the drum 14 such that adjacent portions of the periphery of the caliper roller 42 and the drum surface are move together between them, that is, in the same direction and at the same speed. In this way, the ice flakes are crushed but not ground between these adjacent portions, thus counteracting the formation of too small ice particles. These ice particles are then swept past the caliper roller 42 by the flow to ai e which comes from the air discharge manifold 50 on the blade 48 and in the outlet duct 12. Over an area defined by an arc A 3 which slopes from the clearance 41 to the pipe 34, the ice layer is thus removed from the mbor surface 20 and the drum surface is prepared by the blade 48 to receive a new layer of ice. ice. The > ?) - c & ~ > The au is discharged from the pipes 34 and 36 and does not form in ice particles. It is collected by the channel 14 and passes through the drain 22 and the drain pipe 24. The harvester roller 40 can be coordinated with the drum 14 to rotate in a synchronized relationship with the, in the directions indicated by l3 arrows D, by the reduction gear 28, but you can alternatively turn 1 ibremen e. The air discharge manifold 52 can be omitted in cases where it is found that the air discharged by the manifold 50 is sufficient to achieve the fication and transport of the ice particles from the play 46. However, the manifold 52 or other conveying and fluidizing inlets (not shown) can also be used to provide fluid flow for a desired pressure raising action in the box 10 through the control valves 74, 75 , 76 (figure 3) in order to improve the transport and formation of jets. The height of the projections 44 of the caliper roller 42 is proportional to the thickness of the ice layer on the drum surface 20 which, for purposes of ice-jet cleaning is preferably of the order of 0.158 cm to 0.476 cm. The spacing between the projections 44 must be within the same range and the caliper roller 42 is preferably located such that the joints of the projections 44 are at least 0.0793 cm from the drum surface 20. This arrangement is suitable for fracturing the ice layer that forms on the drum surface 20 and then raising the resulting particles from the surface of the drum 20 with a minimum amount of "snow" generated by the pulsing of the ice. The fractured pieces of ice or the ice flakes not released from the drum surface 20 are thus removed by the blade 48 comprising a non-abrasive scraper co or for example an aquaphobic plastic knife. To avoid the "snow" solution, an additional reduction in particle size can be carried out, if required for a better cleaning effect by jets, after the transport of the particles from the outlet duct 12 and by means of example, of an effective nozzle jet head in accordance with that presented in the aforementioned copending patent Serial No. 08 / 203,584. In any case, the profiles of the harvest and calibration rolls are designed to produce high quality cold dry particles for storage, transport and subsequent fluidized calibration, if required for a better cleaning effect by jets. The harvesting roller 40 can be omitted. When the harvesting roller 40 is provided, it has the advantage of being in contact with the ice and of releasing the ice from the drum surface 20. However, the harvesting roller 40 has the disadvantage of producing large ice flakes of random shapes which must be broken again until the desired particle size is achieved and because it must correspond to the capacity of the calibrator roll 42 without the production of too fine ice particles, which would result in the packing of the apparatus. When the harvester roll 40 is omitted, the periphery of the caliper roll 42 can be designed with a suitable profile to produce the appropriate particle size by means of the invention ion and the ice calibration in one step, thus combining the calibration and the harvest. In general terms, the smaller the particles formed or calibrated, the greater the difficulty in avoiding the accumulation of fine particles. A profiled harvester / harvester will normally remain free of particles provided they are not adhesive, for example, in the case of water ice, dry and cold will be defined by the brittle fracture when removed from the forming surface, and the surfaces of treatment will preferably be water-based. If required, the profiled harvester / harvester can also be cleaned mechanically by devices such as a rigid brush which, in the case of water ice, uses waterproof bristles such as nylon or the like, as described above. details below with reference to figures 4 and 5 or by means of a saw blade in the form of a saw properly fixed near the calibration and harvesting rollers. Fixed blades operating on a forming surface have been employed and are known in the art, but they produce fine "shaved" particles and do not produce discrete calibrated particles and therefore have no useful value for the application of jets and cause agglomeration, accumulation and transport problems. For the purposes of particle production, the fixed blades are preferably used to clean the ice parts not previously removed. The present apparatus uses internal stresses in the ice sheet to fracture into uniform sizes instead of scraping, grinding or grinding. The fractionation must be carried out with a minimum relative speed, and by means of pressure applied by shaped shapes in such a way that the natural fragility and the e? shrinking or shrinking of the material releases it from the surface of the drum, and also from the harvester and caliper rollers. The drive and calibration must be performed by means of forces directed in a pattern to produce desirable particle sizes, using the internal tensions of the solidified ice instead of an important energy coming from the calibration roller. Accordingly, the double profile rollers of the prior art and the impact mills are less effective than the present apparatus. The initial function of the sweep air from 50 is to dislodge large chunks of ice or large ice flakes and calibrated particles from the drum surface 20, harvester surfaces and caliper roller surfaces 40 and 42 and from the walls of the to 10. It is preferred that the sweep ire be under pressure.
In addition to the advantages of an ice unit under high pressure to control humidity, the high pressure improves the quality and density of the ice formed in the ice maker by minimizing the formation of air bubbles in the ice, and helps seal of the system (eliminating any leak). In addition, the high pressure proposes a pulsing force for the sweeping and flow of the ice particles, for transport to the exit point 12 and to overcome a resistance of the ducts in longer transports towards the pressure rise accelerator or to the discharge jet head, if included. The high pressure also improves the performance of the pressure booster and the discharge jet head, where the final discharge is controlled by a construction in such a way that the transport speed within the transport duct is kept low to avoid degradation of the particles. In the case of ejector-type nozzles that are based on low melting injuries, the high pressure can cause a large positive pressure gradient, thus increasing the driving force behind the particle flow. It is important to note that the elevation of the pressure of the solidification and transport system does not imply velocity in the wood or transport wood. The speed and the related disintegration and the accumulation of heat can be controlled by means of mechanical resistances or, more simply, pneumatic generated by the transport pressure elevators or jet head. The effective nozzle presented in my aforementioned copending patent application no. Series 08 / 203,584, offers an improved system control capability. The sweep air pressure inside the sealed box 10 with a correct control of the sweep air could have a pressure from 0 t < g / m2, which is suitable for the pre-cooling of the entire system and the transport duct, and cooling of the particles and will allow a design of low pressure container boxes at low cost. However, a pressure equal to or greater than 35,155 t.g / m2 on atmospheric pressure should be used to obtain an optimal char cleaning effect. The sweep air should have a low level of humidity and temperature so as to maintain the hardness and dryness of the ice particles formed. In the case where the ice formed requires additional cooling, the wetness and temperature must be maintained to facilitate friability. The height of cooling and drying of the sweep air can be remitted by using acceleration air from a smaller cavity in the pressure-raising accelerator and discharge head. In addition, a slightly more humid sweeping medium and a slightly higher temperature can be used to reduce the overall energy consumption of the system if the ice occurs at low temperatures of -10 ° C or less. For the production of ice at these temperatures, the sweeping air requires only to be dehumidified at the pressure dew point temperature of the water in order to achieve treatable conditions of friability, cooling, fluidification and transport. . Gases other than air generally do not require dehumidification. The dehumidification of the air is carried out by means of the treatment of the compressed sweep air (70.310 - 105.465 l ~ g / m2 on the atmospheric pressure) with filters and traps for the removal of particles and oils, and post-pressurizers of air. normal air / water for initial dehumidification. The final drying, if required, can be carried out in two steps. First, the sweeping air will be cooled just above the freezing point of the water and dried by a refrigerated heat exchanger that will remove virtually all of the water content. All of the treatment equipment described above is known in the art. Al erna i amente, secant dryers or vortex tubes can be used. A final heat exchanger will cool the air to a temperature between -18 ° C and ~ 12 ° C. By releasing this air, if the pressure is reduced within the sealed channel, the air will pan and reach even lower temperatures compatible with the formation of ice, an additional cooling of the ice particles and counteract the penetration of heat. throughout the system and during transport. The pressure, temperature and humidity ranges described above provide a smooth flow and prevent agglomeration and clogging. Variation of the positive pressure gradient between the solidification unit and the pressure rise accelerator or the discharge jet head can be carried out by modulating the sweep air inlet in the sealed cavity and its resulting pressure or by an adjustable fluidized pneumatic restriction located at the junction of the treatment unit and the transport flow, the modulation of an effective nozzle, or a combination of all. In the case of treatment with jets, the particle flow of ice can be controlled with greater precision and optimized mechanically or pneumatically with the nozzle of the effective type. The rate of ice processing can be varied by modifying the speed of the forming surface 20, the supply and the temperature of the coolant or the speed of the supply of water on the drum surface 20. When energetically or otherwise In a combined manner, the relative downstream pressure in the transport duct can be emptied, in accordance with the written one, against the effect of the air pressure of sweep or the pneumatic repression, or the pressure riser or accelerator, thus expanding Adhere to the range of possible operational flow rates only. Referring now to Figure 3 there is shown a block diagram of a jet cleaning system incorporating a particle production system used in accordance with the present invention, indicated generally by the reference numeral 60, diagrammatically illustrating the system of fluidized particle production illustrated in Figures 1 and 2. The drum for making ice 14 is illustrated in Figure 3 in condition connected to the refrigeration unit 18 by means of pipes 24 and 25. The spray pipes 34 and 36 are connected to a water reservoir 62 by means of a pipe 63 for supplying water from the water reservoir 62 to the drum 14 and the drain pipe 16 returns the excess water from the drum 14, through a liquid-only flow restrictor similar to a steam condensate trap 64, to the water reservoir 62. A compressed-air source 66 is connected through a dryer and cooler of air 68 and through a manual or automatic opening / closing valve 70 to the particle production system 60. More particularly, the valve 70 is connected via a line 72 to the air discharge manifold 50 and through a valve 74 of two directions OPERATION / VACUUM, a LOAD 75 valve and a VACUUM valve 76 to the manifold 52. By manually adjusting the valve 74, the compressed air from the compressed air source 66 can be supplied through the valve 75 until the system is in operation to produce particles, and through the valve 76 while the system is idling. The valves 75 and 76 can be manually adjusted to the preset level and then automatically control the pressure and flow supplied to the air outlet manifold 52 and consequently the resulting production in the box 10. The dryer and air cooler 68 is located also connected through an OPEN / CLOSED valve 78 and an adjustable pressure control valve 79 to an accelerator 80. The object of the accelerator 80 is to accelerate the fluidized flow of particles supplied from the outlet duct 12 through the hose 82 to a jet head 84, from which the particles are discharged through an outlet nozzle 36 to impact against a white surface 88. The arrangement of the accelerator 80, the jet head 84, the outlet nozzle 86 is described in more detail in the aforementioned copending patent application no. No. 08 / 203,584, and therefore will not be described in greater detail here. The purpose of the dryer / in dryer 68 has been described. In some cases, the dryer / cooler 68 may be omitted, and the process air may be supplied through another source 94. Also, in cases where transportation through the hose 82 is adequate, paricularly when the When the pressure is present, the accelerator 80 and its fluid supply in motion from the dryer / cooler 68 may not be required. The compressed air from the source 66 / of compressed air is supplied to the jet head 84 through an opening / closing valve 90 and a pressure control valve 92. If desired, an air source can be employed. compressed or other alternative fluid to supply or replace the dryer or cooler the dryer or air cooler 68. The particle production system 60 is provided with a safety ring valve against overpressure 96 for venting the air to the air. to the atmosphere in case of an excess pressure inside the ca 10. Figures 4 and 5 show an apparatus illustrated in figures 1 and 2. As shown in figures 4 and 5, a brush indicated generally by means of the reference number 100 is mounted in the vicinity of the outer surface of caliper roller 42, with the bristles of the fabric 100 rubbing against the surface of the roller to remove any piece of ice remaining on the part of the roller. the surface of the roller 42 that they have taken care of the most finds the location in which the ice particles are formed. The brush 100 is fixed by means of nuts 104 and bolts 106 on a support part 108. As can be seen from FIGS. 4 and 5, the fabric 100 is equipped with an elongated slot 112 through which the The bolt 106 extends in such a way that the brush 100 can be adjusted in position relative to the caliper roller 42 and then fixed by tightening the nut 104. The brush 102 is adjusted in the same manner in position relative to the caliper roller 42. Under the the support plate 108, there is provided an air outlet manifold 114 in the form of a perforated pipe having outlet openings 116 directed towards the caliper roller 42. Any piece of ice that remains on the surface of the caliper roll 40 after the Calibration of the ice between the caliper roller 42 and the drum 14 can be removed by means of the air discharged from the air outlet manifold 114 and by means of the brush 100, and is then guided to the Support plate-? 100 towards the outlet duct 12. As a result, the brush 100 can be replaced by a fabric 102 mounted on a support plate 110 which are illustrated in interrupted lines in Figures 4 and 5. Below the support floor 110 is The two output manifolds 118 and 120 are provided. The air outlet manifold 118 has outlet openings 122 directed towards the caliper roller 42 while the air outlet manifold 120 has an outlet opening 124 directed towards the outlet filter 12. The ice particles, and also the ice remaining on the part of the surface of the caliper roller 42 that moves past the drum surface 14 are fluidized by air jets coming from the outlet openings 122 of the manifold 118 air vent. The air that comes from the ionic manifold 120 then helps the movement of these particles to the outlet of the duct 12. As can be seen from Figure 4, a scraper blade 126 replaces the doctor blade 48 of the figure 2, and serves to guide the ice particles towards the outlet filter 12. The brushes 100 and 102 can, if desired, be replaced by suitable profiled scraper plates of aquaphobic material. In the same way, the scraper 126 is preferably formed from an aquaphobic matepal ready to counteract the deposition of ice particles on the scraper 126. It will be understood from the foregoing description and it will be apparent that various modifications and alterations can be made in relation to the form, construction and arrangement of the parts of said invention without departing neither from the spirit nor from the scope of the invention in accordance with that defined by the appended claims, the forms described herein s >; n only preferred embodiments of the invention.