Method and apparatus for producing a solid cryogenic-mechanical cryogenic abrasive from water in a countercurrent process, as well as method and apparatus for cleaning surfaces with the produced cryogenic abrasive.

Abstract

A method for producing a solid cryogenic abrasive from water for cleaning bodies, surfaces, and interiors, wherein water is sprayed both vertically and horizontally from several different nozzles with different directions of action into a closed cryogenic tube, which can be cooled internally to a temperature of -185 °C by spraying and releasing liquid nitrogen, such that the directions of action of the individual nozzles overlap in a given area, and a further quantity of nitrogen is injected into the area, depending on the quantity of water introduced, which can be varied in specific areas by combining several nozzles to maintain the energy balance, and turbulence and collisions occur within the cryogenic tube due to the different spray parameters and directions of action.which promote the formation of differently sized water ice particles, wherein the amount of water to be introduced is divided in a variable ratio and the larger proportion of water is sprayed from below at a differential pressure of 0.5 to 6.0 bar, preferably 0.8 to 3.5 bar, and the water droplets describe a parabolic path with decreasing speed and, due to the high temperature difference, freeze from the outside and the thin ice layer in the area of ​​effect, where the path of the water droplets sprayed from below has its inflection point, is sprayed horizontally with the smaller proportion of water from laterally arranged pairs of opposite spray nozzles at the level of the area of ​​effect, at a low differential pressure of 0.2 to 0.6 bar, preferably 0.3 to 0.4 bar, in such a way that one or more further ice layers can form and these larger water droplets fall downwards at increasing speed.where individual water droplets are slowed down by a collision with the water droplets sprayed from below, the water droplets coming from below burst, and thus a water-ice mixture with different droplet sizes and shapes is created.

Description

[0001] The invention relates to a method and a device for producing a low-residue / residue-free aggressive blasting medium from cryogenic ice particles of varying sizes and geometric shapes. This is achieved by spraying water from multiple nozzles, some in opposite directions, into a cold nitrogen atmosphere within a closed cryogenic tube. To maintain a balanced energy level between the introduced water and the nitrogen atmosphere in the cryogenic tube, liquid nitrogen is additionally injected. The cryogenic tube can be designed to be either stationary for the production of large quantities of blasting medium or portable for on-site production directly at the blasting system for specific applications.The blasting medium made from deep-cold water ice is a new blasting medium available that has cryogenic and mechanical properties and leaves no or only minimal residue when used.

[0002] Several blasting methods are known. These largely mechanical processes utilize different blasting media, such as glass beads, slag, sand, or salts, which are propelled onto the surface to be cleaned with water or compressed air. A disadvantage of these cleaning technologies is that, on the one hand, blasting media residue can accumulate in the surrounding area and within the equipment being cleaned, and on the other hand, the surface of the components can be damaged.

[0003] In addition to purely mechanical methods, thermal methods, known as cold blasting, are also used. These methods primarily employ CO2 dry ice at a temperature of approximately -75 °C as the blasting medium. This material sublimates after blasting and evaporates as a gas. The disadvantages of this blasting medium are its low corrosiveness and its sublimation properties.

[0004] From WO 2003 101667 A1, it is known that CO2 pellets are used as a solid blasting medium for cleaning surfaces. The CO2 pellets act as a soft, non-abrasive blasting medium, thus preventing damage to the surface being cleaned. The temperature of approximately -75°C of the CO2 pellets creates a thermal stress between the contaminant and the surface of the component being cleaned, leading to the removal of the contaminant (cryogenic effect). CO2 pellets, CO2 snow, or generally CO2 particles and compressed air are used as the energy carrier. However, a disadvantage of cleaning with CO2 as a blasting medium is its low abrasive effect. This low abrasiveness limits the range of applications for this cleaning technology.

[0005] German patent DE 103 09 191 A1 discloses a device for dry ice blasting using a mixture of compressed air and dry ice for cleaning surfaces. The brittleness of the CO2 pellets has proven to be a disadvantage. Due to this brittleness, approximately 70% of the CO2 pellets are partially lost upon impact with the surface to be cleaned, or have a negative impact by cooling the surrounding area. For effective use of CO2 blasting technology, a temperature difference between the contaminant to be removed and the substrate is required. The contaminant is cooled by the CO2 pellets, creating the necessary temperature difference or thermoelectric stress. This poses no problem for heated components. The heat capacity, and therefore the temperature difference, remains nearly constant.For thin-walled or unheated components, the heat capacity and thus the temperature difference decreases, while the cleaning performance also decreases.

[0006] In DE 100 10 012 A1 and DE 201 15 013 U1, CO2 pellets and, to increase abrasiveness, an additional blasting medium that is solid at room temperature are added to the compressed air stream. A disadvantage of this method, however, is that some of the added solid blasting medium remains in the system, and dust generation cannot be avoided. Furthermore, the low consistency of the ratio between the CO2 blasting medium and the additional blasting medium is a drawback.

[0007] DE 100 36 557 A1 describes a device for adding solid blasting media as a third blasting medium to the CO2-air mixture. Disadvantages include the inconsistent ratio of CO2 pellets to the additional blasting media and the high wear in the metering unit.

[0008] It is known from the literature that the hardness of ice increases with decreasing temperature. At a temperature of -120 °C, the hardness is said to be approximately 5 Mohs, which corresponds to the hardness of glass.

[0009] US Patent 5367838A describes a device in which ice water at a temperature of approximately -30°C is blown onto the contaminated surface for cleaning purposes using compressed air. The low hardness of the ice and the formation of condensate due to the moisture in the blasted air proved to be disadvantages, leading to a reduction in cleaning performance.

[0010] German patent DE 35 05 675 A1 describes a method for surface ablation in which water ice particles at a maximum temperature of -30°C are added to a water jet. The water ice can also be formed by ice-forming nuclei within the water jet. A disadvantage of this method is that no cryogenic effect occurs; only mechanical ablation takes place, and even that is minimal.

[0011] German patent DE 10 2006 002 653 B4 describes a process in which a specific quantity of water is added to a stream of dry ice. In this cleaning process, the dry ice has an active function, as the resulting mixture is used for textile cleaning, and the cleaning agent is released as a gas after the washing process, thus eliminating the need for rinsing.

[0012] In DE 34 34 163 A1, water is added to the CO2 snow produced when liquid CO2 is depressurized, resulting in the additional formation of water snow. This mixture is pelletized and blown onto the surface to be cleaned using a water jet or compressed air.

[0013] US Patent 5,785,581 A describes a system in which a cryogenic liquid, preferably liquid nitrogen, is used as a coolant to produce ice particles.

[0014] In this process, water droplets are introduced under pressure into a cold gas stream within a freezing tube, where they are converted into ice. Using the pressure difference, the ice is then blown from the nozzle onto the surface to be cleaned. Again, only a minimal mechanical effect is observed, as the ice temperature, due to the short distance within the freezing tube, is only around -25 °C.

[0015] German patent DE 689 146 57 T2 describes a method for producing ice water spheres for cleaning surfaces. This device is only suitable for stationary use, as it is designed to form a closed unit, preventing the ice water particles from coming into contact with the ambient air and thus preventing condensation.

[0016] EP 0 225 081 A1 describes a method for producing microparticles from frozen water, in the size range of 5 to 300 µm. This water ice, which is formed by briefly passing a cold, highly viscous liquid through it, does not have the temperature required for aggressive cleaning and a condensate film forms immediately upon contact with the ambient air.

[0017] German patent DE 10 2010 020 618 A1 describes a process for producing CO2 pellets or CO2 particles with increased mechanical hardness and abrasiveness, in which CO2 water ice particles are manufactured by adding water. A disadvantage of this method is that the CO2 water ice particles must be crushed for blasting, and the required pressure creates a water film that reduces the cleaning performance. German patent WO 2015 / 074765 A1 describes various methods for producing water ice. A disadvantage of this method is that the water ice must be crushed again to obtain blasting-capable particles, or contact with the ambient air is unavoidable. A cylinder is also described that allows the production of water ice particles of different sizes using various nozzle sizes. A disadvantage of this method is the relatively inflexible cooling by spraying or...De-icing liquid nitrogen has proven problematic, as it aims to simultaneously create a cold gas atmosphere and cool the injected water droplets. However, a relatively stationary gas atmosphere forms around the water droplets or ice particles, negatively impacting further cooling. The manufacturing process itself has also proven to be a disadvantage. Only the actual fall time is available for cooling. The required spray velocity accelerates the free fall of the water droplets, thus reducing the cooling time. This limits the size of the ice particles. Production cannot be continuous but must be interrupted after a certain period to allow for the removal of the finished ice.

[0018] German patent application DE 102015209994 A1 describes a method and device for cleaning a jet engine with solid particles such as dry ice and water ice. A disadvantage of this method is the use of commercially available crushed ice at a temperature of approximately -12 °C, which has low hardness and produces a film of water during crushing, negatively impacting cleaning performance. The size and high noise level of the device have also proven to be disadvantages.

[0019] German patent DE 10 2020 000018 A1 describes a method in which the falling velocity of water droplets sprayed from above is slowed by a counter-current generated by the circulation of the cold nitrogen atmosphere, thus extending the freezing time of the water droplet. The high design and energy costs required for its implementation have proven to be a disadvantage.

[0020] DE 10 2019 109 860 A1 describes a method for producing water ice spheres by introducing water at high pressure through a microsieve into a cold atmosphere created by the flow of air through liquid nitrogen, freezing in the cold atmosphere, and then extracting it via a collecting funnel. A disadvantage of this method is that only one particle size can be produced, and due to the relatively short freezing time, the particles are not completely frozen and still have a high water content, making storage and transport impossible.

[0021] WO 2015 / 074765 A1 describes a process for producing a blasting medium from water, in which specially purified water is introduced in droplet form into a liquid refrigerant. A disadvantage of this method is that the frozen water droplet, coated with refrigerant, enters the transport container and, upon contact with the ambient air, freezes into larger pieces of ice due to condensation. In a further development of this process, the water droplets are sprayed with a refrigerant while in free fall. The disadvantages of this method, besides the required height to ensure the necessary freezing time, are the refrigerant coating that forms.

[0022] Analysis of the state of the art has shown that standard CO2 dry ice blasting is suitable for contaminants that become brittle due to the cold of the blasting media or sublimation. Its aggressiveness is low due to its low hardness, comparable to that of gypsum. By crushing the commercially available CO2 pellets—various CO2 blasting systems are equipped with appropriate devices—the performance of the CO2 blasting systems can be increased and the blasting media consumption reduced. However, this does not increase the aggressiveness.

[0023] The addition of solid blasting media, as described in DE 100 36 557 A1 and DE 102015209994 A1 or / 1 / the company brochure of Cryonomic “Abrasives Dry Ice Blasting” and / 2 / the company brochure of DCA Deckert Anlagenbau GmbH “New Generation Dry Ice Cleaning”, combines the cryogenic effect of CO2 dry ice with the mechanical effect of the solid blasting media, thereby increasing the aggressiveness and significantly reducing the dry ice requirement. A disadvantage is the retention of the solid blasting media in the system and the potential for surface damage.

[0024] From / 3 / A. Momber “Handbook for the Surface Treatment of Concrete” and / 4 / B. Karpuschewski “Basic Considerations on Deburring as a Novel Method for Deburring Complex Components”, it is known that the hardness of water ice is temperature-dependent. The hardness of water ice is inversely proportional to its temperature. This means that the hardness of water ice increases with decreasing temperature. Thus, water ice at a temperature of -10°C has a Mohs hardness of 2, comparable to gypsum. In comparison, water ice at a temperature of -120°C has a Mohs hardness of 5–6.

[0025] The processes described in US 4 974 375 A and DE 689 14 657 T2 are designed as stationary plants for the production of a specific particle size and are not suitable for mass production.

[0026] It is logical to use water ice with a hardness of approximately 5 Mohs as an abrasive. The solutions presented have demonstrated that water ice at low temperatures can, in principle, be produced, but no systems for the continuous production of blasting-grade cryogenic water ice in various particle sizes are currently available on the market.

[0027] Several technologies for the production of water ice are known (e.g., / 5 / company publications of ZIEGRA, or / 6 / company publications of Kälte Berlin). The produced water ice is mainly used for cooling in the food industry and has a temperature down to -25 °C. The water ice is manufactured and sold in blocks, as slices, as nuggets in various sizes, or as crushed ice.

[0028] This commercially available water ice in the form offered is unsuitable as an abrasive. Firstly, its structure is too large, and secondly, its hardness is too low. To utilize the advantages of brittleness and the multiple uses of individual particles that water ice offers over CO2 dry ice, a small, blasting-capable particle size is required.

[0029] The inventor discovered through experimentation that further processing of the offered ice water, e.g., by further cooling and subsequent crushing, even in several stages, does not bring the desired result, since crushing, regardless of the type of crushing, exerts mechanical pressure on the ice water, which in turn leads to the formation of a water film (ice skating effect) that causes the crushed ice particles to freeze together immediately.

[0030] In / 7 / “Ice blasting / deburring – an innovative concept for problem-oriented deburring of components and workpieces,” a cryogenic tube is described that can be used to produce fine water ice particles by spraying water into the cold nitrogen atmosphere inside the cryogenic tube at a pressure significantly higher than that prevailing inside the tube. A disadvantage of this method is that only a specific particle size, dependent on the spray nozzle parameters, can be produced. Another disadvantage is the inconsistent application of water and nitrogen.

[0031] Another disadvantage has proven to be the immediate formation of condensate upon contact of the water ice with the ambient air. During filling after production and transfer to the blasting device, contact with the ambient air causes condensate to form on the surface of the water ice particles, leading to the refreezing of the individual particles. In further experiments with the cryo-tube described in / 7 / , the inventor discovered that the exposure time to the cold is reduced by the interaction of the falling and spraying velocities, since the spray pressure imparts a certain velocity to the water droplets, which increases their falling speed. Furthermore, the inventor recognized that the ratio of the volume of water introduced to the droplet surface area is crucial for ice formation.The smaller the water droplets, the larger the total surface area and thus the heat transfer surface from the interior of the water droplet to the surrounding cold gas atmosphere in the cryo-tube. At the same time, a gas layer forms around the small water droplets, which negatively affects heat transfer.

[0032] Furthermore, the inventor discovered during the experiments that the generated water ice particles were larger than the sprayed water droplets. This suggests that several water droplets must have coalesced after spraying.

[0033] Since the prior art has not provided a satisfactory solution for the continuous production of cryogenic water ice in various sizes, the object of the present invention is to find a method and a device for producing a water ice-based blasting media that is more aggressive than CO2 particles and leaves relatively no residue. Furthermore, the device for producing the blasting media should be adaptable to the operating conditions and the required quantities. In addition to its thermal effect, the blasting media should also possess high aggressiveness so that contaminants on the surfaces of components can be removed without leaving any residue. In particular, the surface of the component should not be scratched or roughened.

[0034] Furthermore, the object of the invention is to find a way to store and gently transport the blasting media, as well as a device for processing the cryogenic blasting media.

[0035] The problems are solved by a manufacturing process for cryogenic blasting media based on water ice according to claim 1, and a device for manufacturing this blasting media according to claim 3, as well as a method for cleaning surfaces and components according to claim 6 with a device adapted to the blasting media. Advantageous embodiments are described or specified in the dependent claims.

[0036] The shape and size of the manufactured ice water particles are determined by the application. If the ice water particles are to be used for surface compaction, large spherical particles are preferred, which are applied vertically and at high speed to the surface to be treated.

[0037] In subsequent experiments, the inventor discovered that the challenge of producing a water-based blasting medium with varying particle sizes in a single operation could be surprisingly solved by spraying water in small droplet form—the droplet size of which depends on the chosen spray nozzle and spray parameters—from multiple nozzles with different spray angles and, in some cases, different directions of action into a cold atmosphere. This creates a vortex flow that promotes collisions between the water droplets, thus influencing the size of the resulting ice particles. Due to the significant temperature difference, a thin layer of ice forms immediately. Depending on its thickness, this layer either shatters upon collision, producing angular fragments, or it forms another film of water to create a new ice layer.

[0038] It was further discovered that ice formation depends on the freezing time. With free droplet formation, the freezing time corresponds to the fall time. Since the droplets are introduced into the cryo-tube with a differential pressure and thus a relatively high initial velocity, the freezing time is reduced.

[0039] If, however, the water is sprayed from below at a specific angle to the vertical, the longer path taken by the water droplets results in a significantly longer freezing time. The water is introduced at a speed and spray height that depend on the pressure. As the spray height increases, the speed decreases and is zero at the inflection point. The spray angle is chosen so that the lines of action of the individual nozzles intersect at the height of the inflection point, within the effective area. From the inflection point onward, the water droplets, or the partially frozen water droplets, fall freely downwards.

[0040] At the turning point, lateral spray nozzles are arranged in pairs opposite each other so that the spray jets meet in the middle of the cryo-tube in the effective area and are thereby slowed down, forming larger water droplets, and also fall downwards in free fall.

[0041] Experiments have shown that there is a point at which the ice layer surrounding each water droplet becomes so stable that it no longer breaks upon contact with other drops or the inner wall of the cryo-tube, nor does it form an ice layer on the inner wall. Due to the multitude of influencing factors, it is very difficult to determine this point precisely.

[0042] The inventor has determined through numerous experiments that by maintaining a constant temperature inside the cryo-tube and a high temperature difference between the introduced water and the interior of the cryo-tube, as well as by ensuring a balanced energy balance between the amount of water introduced and the amount of nitrogen sprayed, ice formation can be influenced in such a way that a stable ice layer is present when the effective range is reached.

[0043] The free fall of water droplets from the effective area or of water droplets sprayed laterally can be slowed down by a counter-current. The inventor achieves this by spraying the water from below, at a specific angle opposite to the direction in which the water droplets fall from the distributor head.

[0044] Depending on the speed of the amount of water sprayed from below, the path of the individual water droplet is lengthened compared to a water droplet sprayed from above, and the speed of the water droplets is slowed down, thus extending the time available for freezing and the formation of a stable ice particle.

[0045] These findings led to the development of a manufacturing technology characterized by the introduction of water into the nitrogen-cooled cryo-tube in different, sometimes opposing directions, with different parameter combinations of spray pressure and spray quantity, while maintaining a stable energy balance.

[0046] Heated spray nozzles introduce water as small droplets at an adjustable differential pressure, depending on the chosen nozzle shape.

[0047] The main volume of water is sprayed into the cryo-tube from below through several heated nozzles. This ensures that the water traverses the height of the cryo-tube twice at different speeds, partially reducing the falling speed of the water droplets from the side spray nozzles. The relatively small amounts of water sprayed from the opposing pairs of side nozzles meet in the effective zone, their intensity reduced, and simultaneously impact the water droplets sprayed from below, which are slowing down and reversing their direction of travel.The collision of partially frozen water particles introduced with varying parameters within the operating area causes some of the partially frozen water particles to burst, while one or more layers of water adhere to other partially frozen water ice particles. Direct cooling with nitrogen then promotes the formation of a partially angular and multi-layered cryogenic water ice blasting medium. The volume and spray height of the water injected from below can be controlled by adjusting the pressure and nozzle dimensions. This allows the size of the cryogenic tube and the quantity of cryogenic water ice produced to be tailored to the specific cleaning task and the technological sequence of the cleaning process.

[0048] For centralized production, a large stationary cryogenic tube with high production capacity, storage and transport capabilities, and a blasting system adapted to the specific properties of the cryogenic water-ice blasting media are required. For small, recurring stationary applications or for service providers with low media consumption, a smaller version of the cryogenic tube coupled with the blasting system can be used.

[0049] A further development of the solution according to the invention involves designing the cryo-tube as a small cryo-tube with intermittent production and placing it directly on the blasting system and connecting it to the blasting system's control system. The water ice is produced in small quantities, depending on the blasting volume required for the application, and dispensed directly into the blasting system at short intervals. To loosen the water ice in the collecting cone or to completely freeze the water ice particles, a small amount of liquid nitrogen is introduced into an uninsulated, closed container outside the cryo-tube. This small amount of nitrogen absorbs heat and expands in volume. The increase in volume during the transition from the liquid to the gaseous state causes a pressure increase in the container, which is measured by a sensor.When a predetermined pressure is reached, a valve opens, and the pressure difference between the container and the cryogenic tube causes pressure equalization via a T-piece installed below the collecting cone, with the outlet valve closed. This process agitates and loosens the ice already present in the collecting cone. Simultaneously, the pressure in the cryogenic tube increases slightly. This slight pressure increase, after the valve on the container closes again, facilitates the discharge of the ice from the cryogenic tube into the blasting system or the transport container.

[0050] A further embodiment of the inventive solution provides that the injector is mounted directly on the cryogenic tube, separated only by a rotary valve. The rotary valve transports the cryogenic ice produced in the cryogenic tube directly into the injector. The rotary valve does not have a metering function, but serves not only to transport the ice but also as a seal between the cryogenic tube and the injector. The transport grooves are slightly spiral-shaped, so that the ice can be metered evenly into the transport gas stream.

[0051] The main advantage of the invention is that an aggressive yet gentle solid blasting medium, combining cryogenic and mechanical properties, can be produced in a targeted manner in a single operation, and its particle size can be controlled. -shape and structure can be determined during manufacturing by combining different spraying conditions and spraying parameters.

[0052] Another significant advantage of the invention is that the cryo-tube required for the production of the blasting medium can be adapted in size and design to the operating conditions.

[0053] Another significant advantage of the invention is that an abrasive is available which enables the regular cleaning of components exposed to high thermal or mechanical stress without "hammering over" any existing microcracks or without scratching the surfaces and the scratches being interpreted as defects.

[0054] Another advantage is that the double cooling, with separate cooling for the cryo-tube and additional cooling for water particles, allows for a lower temperature in the cryo-tube and thus a greater temperature difference.

[0055] Another advantage is that the production of the ice cream, according to a specific program, with variable parameters and a balanced energy budget, can be carried out continuously in one operation, thus ensuring that the quality remains constant.

[0056] It is also advantageous that the blasting media can be built up layer by layer by adjusting the counterflow and spray parameters, thus increasing the cleaning performance through the angular fragments created upon impact. It is also advantageous that the introduced water droplets can be slowed down by the counterflow, the freezing time extended, and their size increased by collision with subsequent water droplets or by coating with water droplets generated by the spray mist of the spray nozzle.

[0057] Another advantage is that the water ice particles can be produced in different geometric shapes, from small almost spherical particles, to angular fragments with smooth or angular surfaces, to large spherical particles, in one manufacturing process and thus adapted to the cleaning task.

[0058] Another advantage is that the forced flow causes the water ice particles to freeze through and prevents the manufactured water ice particles from freezing together in the collection chamber.

[0059] Another advantage of compact manufacturing is that the blasting media does not come into contact with the ambient air from manufacturing to the blasting process.

[0060] It is also advantageous that the size of the cryo-tube can be varied and thus its performance can be adapted to the cleaning process. Another advantage is the possibility of mixing the water ice with CO2 particles or CO2 snow, thereby increasing the thermal effect.

[0061] It is also advantageous that the use of cryogenic water ice as an abrasive and in combination with CO2 particles does not produce any waste requiring disposal.

[0062] It is also considered advantageous that the size of the cryo tube and the production quantity can be adapted to the cleaning task, thus providing a compact, transportable system.

[0063] Another advantage is that the blasting system can process two different blasting media individually or as a variable mixture.

[0064] The invention will be described using 3 exemplary embodiments. In Fig. Figure 1 shows the basic structure of a cryo-tube for the production of cryogenic water ice. In Fig. 2 describes the combination of a small cryo-tube with a blasting system for blasting with cryogenic water ice and / or CO2 dry ice. In Fig. Figure 3 shows a cryo-tube with an attached beam unit.

[0065] The in Fig. The cryo tube shown (1) can be manufactured in different sizes, depending on the application, location, production volume and cleaning technology.

[0066] The cryo tube (1) consists of the tube (2) with lid (3), the collecting cone (4) with outlet (5) and the gas unit (6).

[0067] The outlet (5) consists of the shut-off valve (7), the adapter (8), and the T-piece (9). The adapter (8) allows for the optional connection of a sample container (10), a transport container, or a mixing chamber for the possible addition of dry ice.

[0068] The gas unit (6) consists of the pressure build-up chamber (11) with the heater (12), the valve (13), and the pipe sections (14). One pipe section (14) is connected to the T-piece (9).

[0069] In the collecting cone (4) are several heated spray nozzles (15), which are used individually or in different combinations depending on the quantity of frozen water ice to be produced. The lines of action (16) intersect in the working area (17). In the tube (2) are several, also heated, fine water spray nozzles (18), arranged in pairs opposite each other, at the level of the working area (17).

[0070] The nitrogen required to cool the cryo-tube (1) is introduced via nitrogen nozzles (19) located at different heights within the tube (2). The temperature in the cryo-tube (1) is determined by several sensors (20). The temperature established in the effective area (17) is measured by sensor (21). The amount of nitrogen required to freeze the water, depending on the amount of water introduced, is sprayed in via nitrogen nozzle (22). The temperatures measured by sensors (20 and 21), as well as the amounts of water and nitrogen introduced, are recorded and evaluated by the control system. The system then determines the required amounts of nitrogen for cooling the cryo-tube (1) and freezing the water and supplies them to the corresponding nozzles.

[0071] The finished cryogenic ice collects in the collection chamber (23) of the collection cone (4). To loosen any adhering ice particles for removal, one or more knockers (24) are attached to the outside of the collection cone (3).

[0072] The entire cryo tube (1) is completely insulated (25).

[0073] For the production of cryogenic ice, all valves and nozzles are closed in the initial position. The spray nozzles (15) intended for production are inserted, and the differential pressure experimentally determined for this combination is entered into the control unit. The quantity of cryogenic ice to be produced is also entered into the control unit. Upon receiving the start signal, the control unit opens the nitrogen supply via the nitrogen nozzles (19) and cools the interior (26) of the cryogenic tube (1) to the operating temperature, which is measured and regulated by the sensors (20 and 21). Once the target operating temperature is reached, the nitrogen valves are closed. A pressure sensor (27) measures the pressure building up in the interior (26). A safety valve limits the pressure in the interior (26) of the cryogenic tube (1) to the specified operating pressure.

[0074] Simultaneously with the cooling process, the water supply is prepared. The water, regulated in quantity and pressure by the control system, is sprayed into the interior (26) of the cryo-tube (1) through the spray nozzles (15 and 18). The water droplets sprayed via the spray nozzles (15) fly upwards at a shallow angle and decreasing speed into the effective zone (17). In the effective zone (17), the direction of the water droplets sprayed from below reverses, and they fall freely downwards again. At the same time, the rising water droplets, which are already partially frozen due to the high temperature difference, are sprayed with water droplets from the fine water spray nozzles (18). This causes one or more additional ice layers to form on the partially frozen water droplets.

[0075] In the operating area (17), the rising water droplets directly collide with the falling water droplets. Collisions occur, resulting in the formation of angular water ice particles. The mixture of water droplets and water ice particles that forms in the operating area is intensively cooled by direct spraying with nitrogen from the nitrogen nozzle (22). The amount of nitrogen required for this cooling is determined and regulated by the control system based on the measured amount of water supplied. The resulting cryogenic water ice particles fall downwards and collect in the collection chamber (23).

[0076] By opening the shut-off valve (7) at the outlet (6), the cryogenic ice can be filled into the container docked to the adapter. To keep the cryogenic ice in the collection chamber (23) loose, a small amount of gas, at a pressure higher than the internal pressure in the cryo-tube, is injected at specific, adjustable intervals. The required amount of gas is supplied by the gas unit (6). A small amount of liquid nitrogen is metered into the uninsulated, heated pressure build-up chamber (11). In the pressure build-up chamber (11), the liquid nitrogen vaporizes, and pressure builds up. The timing of the pressure build-up process can be controlled by the heater (12). Once the predetermined pressure is reached, the valve (13) opens. Pressure equalization then occurs between the pressure build-up chamber (11) and the interior (26) of the cryo-tube (1). In this process, the extremely cold water ice located in the collection chamber (23) is loosened.Once the pressure has equalized, the valve (13) is closed and the shut-off valve (7) is opened. The blasting media is forced by the pressure inside (26) into the sample container (10), the blasting system, or a special transport container.

[0077] The in Fig. The small cryogenic tube (28) shown in Figure 2 is placed directly onto the adapter (29) of the blasting system (30). A T-piece (31) and the outlet valve (32) are positioned between the adapter (30) and the small cryogenic tube (28). The small cryogenic tube (28) consists of the tube (33), the welded-on outlet cone (34), and the screwed-on cap (35). The entire small cryogenic tube (28) is insulated (36). Several water spray nozzles (37) are arranged in the outlet cone (34). A T-piece is attached to each water spray nozzle (37), to which the water supply and a nitrogen supply for purging to prevent freezing are connected. This makes it possible to purge the water spray nozzles (37) immediately after water is introduced using a nitrogen gas pulse. The water spray nozzles (37) are heated.

[0078] Nitrogen nozzles (38) are installed in the outlet cone (34) and in the tube (33). Nitrogen is supplied via the nitrogen nozzles (38) to cool the interior (39) of the cryo-tube (28). A further nitrogen nozzle (40) with the valve (41) and the temperature sensor (42) are located in the lid (35). The sensor (42) in the upper section and the sensor (43) in the lower section measure the temperature in the interior (39) of the small cryo-tube (28). A safety sensor monitors the temperature in the lower section of the outlet cone (34). This safety sensor monitors the temperature of the produced ice water (44) and also oversees the production process. If the nitrogen supply is interrupted, the water cannot be frozen sufficiently, water collects in the outlet cone (34), and the temperature rises.If the water supply is disrupted, more nitrogen is supplied than required, and liquid nitrogen collects in the outlet cone (34). This causes a significant temperature drop. The water spray nozzles (37) are arranged at a specific angle to the vertical so that the lines of action (45) of the spray cones intersect in the effective area (46). The sensor (47) is installed in the effective area (46). In conjunction with the control system, the sensor (47) detects and regulates the temperature in the effective area (46), particularly during the manufacturing process, since water and nitrogen particles with different temperatures meet in this area.

[0079] Liquid nitrogen is injected into the interior (39) of the small cryo-tube (28) through nitrogen nozzles (38) at a pressure of approximately 6 bar. The pressure inside (39) is set to approximately 3 bar and is monitored by the pressure sensor (48). The resulting pressure difference causes the nitrogen to vaporize, absorbing heat in the process. The heat required for the transition from the liquid to the gaseous phase is extracted from the water introduced into the tube (33) in the first stage and from the water introduced into the tube in the second stage.

[0080] To prevent the finished ice cream (44) from freezing together in the discharge cone (34) and to facilitate the discharge of small quantities, a specific amount of liquid nitrogen is converted into a gaseous state in a pressure vessel (49) located outside the small cryogenic tube (28). The pressure vessel (49) is not insulated and is equipped with a heater. The heater allows the gas formation in the pressure vessel (49) to be regulated. As the gas formation increases, so does the pressure in the pressure vessel (49). Once a predetermined pressure is reached, a pressure relief valve located in the connecting pipe between the pressure vessel (49) and the T-piece (31) is briefly opened. Due to the pressure difference between the pressure vessel (49) and the interior (39) of the small cryogenic tube (28), pressure equalization occurs. A small amount of nitrogen then passes from the pressure vessel (49) into the interior (39), stirring up the ice cream (44) in the discharge cone (34).This results in a relatively small pressure increase inside (39) the small cryogenic tube (28). If the outlet valve (32) is opened immediately after the pressure valve is closed, the finished, liquefied ice water (44), aided by the increased pressure inside (39), can pass through the adapter (29) into the storage chamber (50) of the blasting system (30). Since the gas formation in the pressure vessel (49) is influenced by the amount of nitrogen supplied and the adjustable heating, the intervals for loading the blasting system (30) with cryogenic ice water can be controlled.

[0081] The blasting system (30) consists of the storage chamber (50) for cryogenic water ice and the storage chamber (51) for dry ice. The metering roller (52) with drive (53) and gearbox (54) is located on the storage chamber (50). To reduce the tendency to be crushed, the intake area of ​​the metering roller (52) is restricted by the scraper (55) and the direction of rotation is predetermined (56).

[0082] The metering roller (57) for dry ice with drive (58) and gearbox (59) is located at the storage chamber (51). Both metering rollers are mounted in the partition wall (64).

[0083] The separately stored and metered abrasive material enters the injector (61) via the mixing shaft (60). In the injector (61), the abrasive material is mixed by being added to a transport gas stream and fed through the abrasive material connection (62) to the blast gun. In the blast gun, it merges with the main gas stream (63). The entire abrasive material-carrying area is enclosed by a casing (65) and surrounded by insulation (66). The space enclosed by the casing (65) is cooled to maintain the stability of the cold abrasive material. This is achieved by a known system consisting of a compressor (69), evaporator (67), and collector (68).

[0084] To ensure a safe and uniform discharge of the abrasive material from the storage chambers, each storage chamber is equipped with a gas connection nozzle (70) to build up a slight overpressure in the storage chambers. To prevent overpressure, a safety valve (71) is provided on each storage chamber.

[0085] For manufacturing, the small cryogenic tube (28) with its outlet valve (32) closed is placed on the adapter (29) of the blasting system (30). Upon receiving the start signal, the control unit opens the main valve in the nitrogen line, and liquid nitrogen flows through the nitrogen nozzles (38) into the interior (39) formed by the tube (33) and the outlet cone (34). The interior (39) is cooled by the expansion of the liquid nitrogen and the associated heat absorption. The temperature in the interior (39) is measured by sensors (42), (43), and (47), as well as a safety sensor. Once the preset operating temperature is reached, the nitrogen supply is interrupted by closing the main valve. The control unit then opens the water supply, and water is injected at a specific angle into the cold interior (39) of the small cryogenic tube (28) through the heated water spray nozzles (37).Depending on the quantity of cryogenic water ice (44) to be produced, the water introduced from one or more water spray nozzles (37) meets in the working area (46) after its velocity has decreased to zero and the individual water droplets have already partially frozen due to the high temperature difference. The partially frozen water droplets sprayed from below are then additionally sprayed with water from the laterally arranged fine spray nozzles (72) in the working area (46) to form one or more ice layers. To ensure and accelerate the complete freezing of the water droplets, liquid nitrogen, the amount of which depends on the amount of water sprayed, is injected from the nitrogen nozzle (40) in the working area (46) after the valve (41) has been opened.The sensor (60) monitors the temperature in the operating area (46) and thus, in cooperation with the control system, regulates the amount of material to be supplied through the nitrogen nozzle (40).

[0086] In parallel with the production of the cryogenic water ice (44), a nitrogen gas is generated in the pressure vessel (49), depending on the small amount of nitrogen introduced and the heating temperature.

[0087] Once the specified quantity of cryogenic ice (44) has been produced, the quantity of ice produced corresponding to the quantity of water supplied, the water supply through nozzles (37) and (72) and the nitrogen supply through nozzle (49) are interrupted. To prevent the residual water in nozzles (37) and (72) from freezing, the nozzles are cleared by a short gas pulse from the pressure vessel (49). The gas valve in the connecting pipe between the pressure vessel (49) and the T-piece (31) is then briefly opened, causing the cryogenic ice (44) in the discharge cone (34) to be agitated. Immediately after the gas valve closes, the outlet valve (32) is opened. The finished ice falls freely, aided by the pressure in the interior (39), into the cooled storage container (50) of the blasting system (30) and is then available for the cleaning process.

[0088] Simultaneously with the production of the cryogenic water ice, the storage container (51) for the CO2 dry ice is filled. Depending on the desired type and composition, the metering rollers (52) for cryogenic water ice are set in motion by the drive (53) with gearbox (54), and / or (57) for dry ice by the drive (58) with gearbox (59). The direction of rotation (56) of the metering roller (52) for cryogenic water ice (44) is mandatory so that the scraper (55) can effectively push the amount of abrasive material exceeding the transport grooves back into the filling chamber (73). The abrasive material conveyed by the respective metering rollers passes through the mixing chute (60) into the injector (61). The injector (61) is permeated by the transport gas flow and is first loaded with dry ice and then with cryogenic water ice.The transport gas stream loaded with blasting media passes through the transport hose to the blasting gun, where it is combined with the high-energy blasting gas stream and blown onto the surface to be cleaned.

[0089] In Fig. Figure 3 shows a cryo-tube with an attached beam unit.

[0090] The small cryogenic tube (28) is mounted on the ice pop metering block (75) via the outlet cone (74). A rotary valve roller (76) is arranged in the ice pop metering block (75) for transporting the cryogenic ice pop produced in the small cryogenic tube (28) into the injector (77). The ice pop metering block (75) is equipped with a scraper (78) that pushes the excess cryogenic ice pop back into the loading chamber (80) via the transport grooves (79). The scraper (78) requires a specific direction of rotation (81) of the rotary valve roller (76) to be effective. The variable speed motor (82) with the gearbox (83) ensures the required adjustable rotational speed.

[0091] The dry ice storage container (84) (85) is mounted on the dry ice metering block (86). The transport roller (87), which is driven by the motor (88) and gearbox (89), ensures the supply of dry ice to the injector (90) by its variable rotational speed. The injector (77) for cryogenic water ice is connected to the dry ice injector (90) via the injector tube (91).

[0092] A portion of the total gas flow is diverted as a transport gas flow and directed via the inlet nozzle (92) to the metering block (86) for loading with dry ice. The dry ice-laden gas flow passes through the injector tube (91) into the metering block (75) and is loaded with cryogenic water ice in the injector (77). From the outlet nozzle (93), the gas flow loaded with abrasive material is conveyed via a blast hose to the blast gun, where it is combined with the main gas flow and blown onto the surface to be cleaned. The rotary valve (76) mounted in the metering block (75) does not meter the quantity of cryogenic water ice required for cleaning, but only transports the produced cryogenic water ice via a rotary valve from the small cryogenic tube (28) into the injector (77).The quantity of cryogenic ice required for cleaning, as well as the composition of the required blasting media mixture, is set at the control panel (95) and implemented by the control unit (94). The control unit (94) meters the amount of water to be introduced through the water spray nozzles (37) and the fine spray nozzles (72) for the required quantity of cryogenic ice, as well as the amount of nitrogen required for freezing through the nitrogen nozzle (40). The produced cryogenic ice is immediately transported into the injector (77) by the rotary drum (76).

[0093] The temperature of the rotary valve (76) and the metering block (75) is influenced by direct contact with the cryogenic water ice on the one hand, and by the temperature of the transport gas stream and the amount of dry ice carried by the transport gas stream on the other. To ensure reliable operation and safe transport of the cryogenic water ice through these fluctuating temperatures in the metering block (75), the temperature in the metering block (75) is measured and adjusted by a metered supply of cold nitrogen gas from the small cryogenic tube.

[0094] Upon receiving the start signal, the control unit (94) opens the main valve in the nitrogen line, and the liquid nitrogen flows through the nitrogen nozzles (38) into the interior (39) formed by the tube (33) and outlet cone (34). The interior (39) is cooled by the expansion of the liquid nitrogen and the associated heat absorption.

[0095] The temperature inside (39) is measured by the sensors (42), (43) and (47) as well as a safety sensor.

[0096] Once the specified operating temperature is reached, the nitrogen supply is interrupted by closing the nitrogen nozzles (38). If the temperature rises above the set limit, the nitrogen nozzles are reopened until the system cools down to operating temperature. The system is ready for start-up once the operating temperature is reached. The required jet parameters are set on the control panel (95), and the system can then be started.

[0097] After the start signal, triggered by actuating the blast gun, the control unit simultaneously opens the water supply, switches on the motors (82) and (88), and opens the supply of the main gas flow. The water is blown into the cold interior (39) of the small cryogenic tube (28) at a specific angle through the heated water spray nozzles (37). Depending on the quantity of cryogenic ice to be produced, the water introduced from one or more water spray nozzles (37) meets in the working area (46) after its velocity has decreased to zero and the individual water droplets have already partially frozen due to the high temperature difference. The partially frozen water droplets sprayed in from below are then additionally sprayed with a small amount of water from the laterally arranged fine spray nozzles (72) in the working area (46) to form one or more ice layers.To ensure and accelerate the complete freezing of the water droplets, liquid nitrogen, the amount of which depends on the amount of water introduced, is sprayed from the nitrogen nozzle (40) into the working area (46) after the valve (41) has been opened. The sensor (60) monitors the temperature in the working area (46) and thus, in conjunction with the control unit, regulates the amount of nitrogen supplied through the nitrogen nozzle (40).

[0098] The production process for cryogenic water ice (44) begins with the spraying of water through the water spray nozzles (37). Simultaneously, the transport gas flow is switched on. As needed, the transport gas flow is loaded with dry ice in the injector (90) of the dry ice metering block (86). The amount of dry ice supplied can be varied by adjusting the rotational speed of the transport roller (87). The empty or dry ice-loaded transport gas flow passes through the injector tube (91) into the metering block (75). In the injector (77) of the metering block (75), the transport gas flow is loaded with cryogenic water ice. The cryogenic water ice (44) produced in the small cryogenic tube (28) is immediately conveyed directly into the injector (77) by the rotary drum (76).The transport gas stream loaded with abrasive material is transported from the outlet nozzle (93) through a flexible hose to the blast gun, where it is recombined with the high-energy main gas stream and blown onto the appropriate surface for cleaning.

[0099] A method for producing the abrasive according to the invention from water, for blasting bodies, surfaces, interiors and the like, is disclosed, which is introduced at a temperature of +1 °C to +95 °C into a nitrogen atmosphere as cold as -185 °C, by dripping and / or spraying from different, partially opposing directions and with different intensity, wherein the main quantity of water is introduced from below and thus counteracts the falling motion of the water droplets introduced from above.

[0100] Furthermore, a device for producing an abrasive from water is disclosed, which has two separate control circuits, one for cooling the cryo-tube and another for freezing the introduced water, which complement each other in their effect and thus positively influence the energy balance.

[0101] Furthermore, a blasting medium produced according to the invention is disclosed which contains solidified water and can be manufactured in several layers and with different structures.

[0102] Furthermore, a blasting medium produced according to the invention is disclosed, which has special shapes and sizes that differ due to the nature of the manufacturing process, and can be manufactured in a range of 2 to 6 mm, preferably 4 mm, for compacting surfaces.

[0103] Furthermore, a device for producing cryogenic water ice is disclosed, which is directly connected to a blasting system and thus enables blasting with cryogenic water ice or with CO2 particles or with a mixture of cryogenic water ice and CO2 particles, wherein the water ice production is controlled depending on the amount of blasting media used in the blasting system.

[0104] Furthermore, a device for producing and loosening the manufactured blasting media and for intermittently filling the blasting system depending on the throughput of the blasting system is disclosed.

[0105] Furthermore, a heated spray nozzle is revealed which can be alternately supplied with water or nitrogen gas.

[0106] Furthermore, the combination of a counter-current cryo-tube with a blasting system designed for processing the cryogenic blasting media produced in the cryo-tube into a transportable compact unit is revealed.

[0107] Furthermore, a transportable system for blasting with dry ice and / or cryogenic water ice is revealed, whereby the transport gas stream can be filled with different quantities in two independent positions.

[0108] Other particularly advantageous features of the invention are: Production of cryogenic ice particles of different shapes and sizes according to a predetermined program sequence. Adjustable and separate nitrogen supply for generating a cold gas atmosphere in the cryo-tube and for cooling the water particles, wherein the amount of nitrogen to be introduced for cooling the water particles depends on the amount of water particles. Targeted production of mixtures of water ice particles with different sizes and shapes of the individual particles. Option to remove the water ice during continuous production. Possibility of increasing the exposure time of the internal temperature to the water particles through targeted counter-current. Possibility of mixing the cryogenic water ice with CO2 particles after production in such a way as to prevent condensation. It has become clear that the present invention provides a novel manufacturing process which, in particular, can produce water ice particles in a novel way from water with a high variable cooling rate and thus with different hardness and in different sizes and layers, by extending the cooling time by generating a counter-current and, if necessary, combine them with CO2 particles, so that a stable, aggressive, yet gentle CO2-water ice mixture is produced.

[0109] The preceding description has made clear numerous advantages of the present invention. Among them, the following are particularly noteworthy: An abrasive is available that combines the advantageous mechanical effect of solid and hard water ice with the thermal advantages of temperatures down to -180 °C.

[0110] The aggressiveness of the water ice or the CO2-water ice mixture can be specifically adapted to the component to be cleaned and the type of contamination.

[0111] It has proven particularly advantageous that it is possible to clean large components in the installed state using the blasting medium according to the invention, without the need for time-consuming installation and removal, since no solid components remain.

[0112] The multi-layered structure of the abrasive material according to the invention, made of solidified water, has also proven to be very advantageous, since its special fracture behavior makes it possible to clean successive levels using the billiard effect, for example in jet engines.

[0113] Another advantage is that the production of the blasting media can be adapted to the cleaning process and automated through adjustable interval-based dosing. Designations 1 cryo tube 2 tubes 3 lids 4 Collecting cone 5 outlets 6 gas units 7 Shut-off valve 8 adapters 9 T-piece 10 sample containers 11 Pressure build-up chamber 12 Heating 13 valve 14 Pipe section 15 spray nozzles 16 Line of action 17 Area of ​​influence 18 fine water spray nozzles 19 nitrogen nozzles 20 sensors 21 Sensor 22 Nitrogen nozzle 23 Collection room 24 Knockers 25 Insulation 26 Interior 27 Pressure sensor 28 small cryo tubes 29 adapters 30 blasting systems 31 T-piece 32 Exhaust valve 33 tubes 34 Outlet cone 35 lids 36 Insulation 37 water spray nozzles 38 nitrogen nozzles 39 Interior 40 Nitrogen nozzle 41 Valve 42 temperature sensors 43 sensors 44 ice pops 45 Line of action 46 Area of ​​influence 47 sensors 48 Pressure sensor 49 pressure vessels 50 pantry ice pops 51 Pantry dry ice 52 Metering roller 53 Drive 54 gearboxes 55 wipers 56 Direction of rotation 57 Metering roller 58 Drive 59 gearboxes 60 mixing shaft 61 Injector 62 Abrasive connection 63 Main gas flow 64 Partition wall 65 Fairing 66 Insulation 67 compressors 68 evaporators 69 collectors 70 gas connection nozzles 71 Safety valve 72 Fine spray nozzle 73 Filling chamber 74 Outlet cone 75 Ice pop dispenser blocks 76 Rotary wheel 77 Injector 78 wipers 79 Transport groove 80 cargo space 81 Direction of rotation 82 Engine 83 gearboxes 84 Pantry 85 dry ice 86 Dry ice dosing block 87 Transport roller 88 engine 89 gearboxes 90 injector 91 Injector pipe 92 inlet nozzles 93 outlet nozzles List of cited non-patent literature: / 1 / Company brochure of Cryonomic “Abrasive dry ice blasting” / 2 / Company brochure of DCA, Deckert Anlagenbau GmbH “Dry ice cleaning of the new generation” / 3 / A. Momber “Handbook for the surface treatment of concrete” / 4 / B. Karpuschewski “Basic considerations on deburring as a new method for deburring complex components” / 5 / ZIEGRA Ice Machines GmbH www.ziegra.com / 6 / Company information Kälte Berlin www.kaelte..berlin.com / 7 / Ice blasting / deburring - an innovative concept for problem-oriented deburring of components and workpieces Petzel, Mathias Master's thesis Faculty of Process and Systems Engineering Institute for Apparatus and Environmental Technology (IAUT) Otto von Guericke University Magdeburg

Claims

[1] A method for producing a solid cryogenic abrasive from water for cleaning bodies, surfaces and interiors, wherein water is sprayed both vertically and horizontally from several different nozzles with different directions of action into a closed cryo-tube, which can be cooled internally by spraying and expanding liquid nitrogen down to a temperature of -185 °C, such that the directions of action of the individual nozzles overlap in an area of ​​action and a further quantity of nitrogen is injected into the area of ​​action, depending on the quantity of water introduced, which can be varied in certain areas by combining several nozzles to maintain the energy balance, and turbulence and collisions occur within the cryo-tube due to the different spray parameters and the different directions of action.which promote the formation of differently sized water ice particles, wherein the amount of water to be introduced is divided in a variable ratio and the larger proportion of water is sprayed from below at a differential pressure of 0.5 to 6.0 bar, preferably 0.8 to 3.5 bar, and the water droplets describe a parabolic path with decreasing speed and, due to the high temperature difference, freeze from the outside and the thin ice layer in the area of ​​effect, where the path of the water droplets sprayed from below has its inflection point, is sprayed horizontally with the smaller proportion of water from laterally arranged pairs of opposite spray nozzles at the level of the area of ​​effect, at a low differential pressure of 0.2 to 0.6 bar, preferably 0.3 to 0.4 bar, in such a way that one or more further ice layers can form and these larger water droplets fall downwards at increasing speed.where individual water droplets are slowed down by a collision with the water droplets sprayed from below, the water droplets coming from below burst, and thus a water-ice mixture with different droplet sizes and shapes is created. [2] Procedure according to the preceding claim characterized byThe nitrogen required for production is supplied in a controlled manner in two separate cycles with different tasks. The task of the first cycle is to establish and maintain the predetermined operating temperature in the cryo-tube in the range of -120 °C to -185 °C, preferably -160 °C to -175 °C, by supplying a certain amount of nitrogen. The task of the second cycle is to regulate the freezing temperature required for water ice formation in the effective range of -160 °C to -185 °C, preferably -170 °C to -175 °C, by a metered supply of an additional amount of nitrogen, depending on the currently introduced amount of water and the required freezing temperature, so that it is introduced simultaneously and in the predetermined ratio with the respective introduced amount of water, thus keeping the energy balance constant. [3] Device for producing a solid cryogenic abrasive from water for cleaning bodies, surfaces and interiors, characterized by , that water from several different interchangeable nozzles with different parameters is introduced both vertically from below and horizontally into a closed cryo-tube supplied with a cold nitrogen atmosphere, wherein the vertically operating nozzles are arranged in the collecting cone, at a certain angle to the central axis of the cryo-tube, such that their lines of action intersect in an effective area dependent on the spray pressure, and a further horizontally acting group of nozzles is arranged in pairs opposite each other at the level of the effective area such that the lines of action lie on one plane and meet in the effective area. [4] Device according to claim 3 for producing a solid cryogenic blasting medium characterized bythat the replaceable nozzles for spraying the water are heated and insulated from the cryo-tube and are blown out immediately after the spraying process is completed by a short pulse of dry nitrogen gas, thus preventing the spray nozzles from freezing due to residual water. [5] Device according to claim 3 for producing a solid cryogenic blasting medium characterized byTo loosen and reliably freeze the manufactured ice pops, a small amount of liquid nitrogen is introduced into a closed, uninsulated container outside the cryo-tube and gasified while absorbing heat. The resulting gas pressure continuously increases, and when a predetermined limit, which is 3 bar above the internal pressure of the cryo-tube, is reached, a valve is opened to blow the nitrogen into the cryo-tube from below. This agitates the ice pops in the collecting cone, preventing them from refreezing, especially during production breaks. Simultaneously, the pressure in the cryo-tube increases, facilitating filling into transport and storage containers or, when connected to a blasting system, the continuous filling of the blasting system. [6] Methods for cleaning bodies, surfaces and interiors, characterized by, that the blasting medium is produced according to a method of claims 1 and 2 or with a device according to one of claims 3 to 5 and is transported, stored and used under refrigeration due to its special properties, and which, to increase its mechanical effect, can be mixed with another blasting medium, preferably with thermally effective dry ice particles, immediately before blasting, wherein the mixing ratio can be changed during the blasting process.

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