EP3822023B1 - Device for dry ice treatment of surfaces and method for treating surfaces - Google Patents

Description

The invention relates to a device for dry ice treatment and in particular dry ice cleaning of surfaces and a corresponding method.

Devices for cleaning surfaces with dry ice are well known. Such devices, which are also sometimes referred to as dry ice blasting systems, generate a dry ice jet in which dry ice particles, such as dry ice pellets, are accelerated by compressed air to a speed of around 300 meters per second and shot at the surface to be cleaned, where they create a local thermal shock. The coating to be removed, such as in particular contaminants, on the surface to be cleaned contracts and the subsequent dry ice particles, in conjunction with the kinetic energy they contain, cause the contaminants to flake off. The dry ice particles sublimate immediately upon impact and leave a dry surface behind.

Dry ice is made from liquid CO2. Liquid CO2 is expanded under controlled conditions in a pelletizer. This physical process creates dry ice snow. This is pressed through an extruder plate into round, hard pellets, which have elongated grains with a diameter of 1.7 mm to 3.0 mm. Dry ice has a temperature of approximately -79 °C.

Carbon dioxide (CO2) is an odorless, non-flammable gas that is 1.5 times heavier than air. The earth's atmosphere normally contains about 0.03% CO2. Today, CO2 is mainly produced as a byproduct of various chemical processes and is stored in tanks after extraction.

Dry ice blasting systems are a modern alternative to conventional industrial cleaning methods. What is unique about using dry ice as a blasting agent is that dry ice particles change into gaseous form, i.e. sublimate, the moment they hit the surface to be cleaned. This means that the surface is left dry and clean after treatment, with no cleaning or blasting agent residues. Since it is a completely dry and electricity-free process, dry ice blasting can be used in areas where other methods are not possible. For example, electric motors and technical systems with electrical, pneumatic and hydraulic components can be cleaned without the need to shut them down or dismantle them. Dry ice blasting is also suitable for a wide range of other applications, such as cleaning machines, electrical installations, any surfaces and shapes.

When cleaning, dry ice particles are accelerated to the speed of sound using compressed air before they hit the surface to be treated. The three different circumstances mentioned above contribute to the cleaning effect: firstly, when the dry ice particles hit the surface at the speed of sound, the coating is loosened and bursts apart - kinetic effect.

On the other hand, the low temperature of the dry ice particles makes the coating brittle, leads to cracking and contributes to its detachment, as the bond between the coating and the surface underneath is reduced. This means that dry ice also gets underneath the coating - thermal effect.

Thirdly, the dry ice penetrates the coating and evaporates instantly, causing the coating to expand by about 700 to 1,000 times in volume. This explosive reaction causes the coating to be lifted off the surface - sublimation effect/explosion effect. A moist layer, such as oil or Grease is carried away by the air stream - similar to high-pressure cleaning. However, unlike high-pressure cleaning, the cleaned surface is left dry and clean.

Since dry ice evaporates immediately when it hits the surface to be treated and therefore leaves no waste product, only the removed layer needs to be disposed of after dry ice blasting. This can usually be swept up from the floor beneath the treated object or removed with the help of a vacuum cleaner.

Dry ice blasting can be seen as an alternative to high-pressure cleaning and other conventional blasting methods that use various blasting media such as sand, water, glass or plastic granulate. It is ideal for removing glue, paint, oil, grease, coal dust, soot, lubricants and bitumen.

Dry ice blasting does not use any chemicals or solvents that are hazardous to health. The operating personnel are therefore not exposed to fumes or similar during cleaning. There are also no disposal costs for such chemicals.

Even though dry ice blasting is gentler on materials and surfaces than high-pressure cleaning and other conventional blasting methods that use various blasting media, the areas of application of dry ice blasting technology are limited with conventional dry ice blasting systems. In particular, conventional dry ice blasting systems, in which the dry ice particles are shot at the surface to be treated at a speed of around 300 meters per second, cannot be considered non-abrasive for certain surfaces. This is especially true for sensitive surfaces such as nickel, chrome and soft aluminum.

In addition, conventional dry ice blasting systems have limitations when it comes to treating textiles or other open-pored objects, Plexiglas, highly polished aluminum and especially ceramics, ceramic honeycombs from 3D production, circuit boards and printed circuit boards. Due to the kinetic energy of the dry ice particles shot at the surfaces to be treated, the area of application of dry ice blasting systems is correspondingly limited.

The publication JP 2010064027 A relates to a nozzle for a device for dry ice cleaning of surfaces and discloses the preamble of independent claim 1.

The publication DE 20 2005 018 952 U1 relates to a dry ice blasting system for blasting an object to be cleaned with a dry ice particle-compressed air mixture, with an ice storage container, an air storage container and a mixing unit for producing the dry ice particle-compressed air mixture, wherein an air treatment system for drying and/or cleaning the compressed air is connected between the air storage container and the mixing unit.

The publication JP 2014206423 A relates to a decontamination system for cleaning contaminated objects, in particular radioactively contaminated surfaces.

The publication US 2014/0367479 A1 relates to a device and a method for dry ice cleaning of surfaces and discloses the preamble of independent claim 12.

Therefore, the present invention is based on the object of specifying a device for dry ice treatment and in particular dry ice cleaning of surfaces, whereby a wider application is made possible while avoiding the aforementioned disadvantages of conventional dry ice blasting systems.

Furthermore, the invention is based on the object of specifying a corresponding method for dry ice treatment and in particular dry ice cleaning of surfaces.

With regard to the device, the object underlying the invention is solved by the subject matter of independent patent claim 1, with advantageous developments of the device according to the invention being specified in the corresponding dependent claims. With regard to the method, the object underlying the invention is solved by the subject matter of the independent patent claim 12.

Accordingly, the invention relates in particular to a device for dry ice treatment and in particular dry ice cleaning of surfaces, wherein the device comprises a dry ice source for providing dry ice, in particular in the form of dry ice particles, a mixing unit that is fluidly connected or connectable to the dry ice source, and a compressed air source that is fluidly connected or connectable to the mixing unit. According to the invention, the The device further comprises a conditioning unit that is fluidically connected or connectable to the mixing unit for adapting a dry ice particle-compressed air mixture provided by the mixing unit to application-specific conditions before applying the dry ice particle-compressed air mixture to the surface to be treated. The conditioning unit is designed to condition the dry ice particle-compressed air mixture in such a way that a predetermined or definable proportion of the dry ice particles in the dry ice particle-compressed air mixture completely sublimates at a predetermined or definable distance from the surface to be treated.

The advantages that can be achieved with the device according to the invention are obvious: by providing a conditioning unit with which a dry ice particle-compressed air mixture provided by the mixing unit of the device can be adapted to application-specific conditions before the dry ice particle-compressed air mixture is applied to the surface to be treated, the dry ice particle-compressed air mixture can be adapted in such a way that the dry ice treatment of the surface is carried out in a completely non-abrasive manner and is therefore extremely gentle on the material and surface, since with the help of the conditioning unit, among other things, the wear caused by the kinetic energy of the dry ice particles in conventional dry ice blasting systems can be prevented.

The dry ice particle-compressed air mixture can be conditioned in such a way that an undesirable coating is removed from the surface to be treated without damaging the underlying layer. The device and the corresponding process can therefore also be used on sensitive surfaces such as nickel, chrome and soft aluminum. Plexiglass and highly polished aluminum can also be cleaned without the surface becoming matt.

By conditioning the dry ice particle-compressed air mixture, the thermal load on the material to be cleaned can be significantly reduced compared to conventional dry ice blasting systems.

On the other hand, the invention provides that the conditioning unit is designed to condition/adapt the dry ice particle-compressed air mixture before application to the surface to be treated in such a way that a predetermined or definable proportion of the dry ice particles in the dry ice particle-compressed air mixture completely sublimates at a predetermined or definable distance from the surface to be treated. In this way, the kinetic The stress on the treated surface due to the impact of dry ice particles at high speed can be significantly reduced. On the other hand, the sublimation effect is still present because the distance in front of the surface to be treated at which the predetermined or definable proportion of dry ice particles sublimates in the dry ice particle-compressed air mixture is selected accordingly.

Thus, according to the invention, the distance of a sublimation area in front of the surface to be treated can be set to suit the application, preferably automatically and even more preferably automatically, using the conditioning unit. The term "sublimation area" is understood to mean the area in which the previously determined or determinable proportion of dry ice particles in the dry ice particle-compressed air mixture completely sublimates.

With the conditioning unit, preferably all parameters of the dry ice particle-compressed air mixture that are essential for dry ice treatment and in particular dry ice cleaning can be adapted to the specific application, before the dry ice particle-compressed air mixture is applied to the surface to be treated.

Thus, according to embodiments of the device according to the invention, it is provided that the conditioning unit is designed to preferably automatically and even more preferably optionally automatically set an average size and in particular an average diameter of the dry ice particles in the dry ice particle-compressed air mixture, in particular in an application-specific manner.

According to the invention, the conditioning unit has at least one filtration device, wherein the dry ice particle-compressed air mixture to be conditioned is passed through this filtration device before the dry ice particle-compressed air mixture is applied to the surface to be treated. The filtration device is designed to only allow dry ice particles with a particle size that does not exceed a predetermined or definable value to pass through. A mesh size of the filtration device is adjustable in order to set a critical particle size of the dry ice particles in the dry ice particle-compressed air mixture, up to which dry ice particles can pass through the filtration unit.

By using the conditioning unit to vary the particle size of the dry ice particles in the dry ice particle-compressed air mixture for each application, the kinetic load on the surface to be treated when applying the dry ice particle-compressed air mixture can be regulated and, in particular, reduced as required.

1. (a) dem zehn- bis sechsfachen des mittleren Durchmessers der Trockeneispartikel in dem Trockeneispartikel-Druckluftgemisch entspricht; oder
2. (b) dem sechs- bis vierfachen und insbesondere dem 4,5-fachen des mittleren Durchmessers der Trockeneispartikel in dem Trockeneispartikel-Druckluftgemisch entspricht; oder
3. (c) weniger als dem vierfachen des mittleren Durchmessers der Trockeneispartikel in dem Trockeneispartikel-Druckluftgemisch entspricht; oder
4. (d) mindestens dem fünffachen des mittleren Durchmessers der Trockeneispartikel in dem Trockeneispartikel-Druckluftgemisch entspricht.

In particular, according to implementations of the device, it is provided that the conditioning unit is designed to preferably automatically and even more preferably optionally automatically adjust the distance of the sublimation area from the surface to be treated depending on an average size and in particular depending on an average diameter of the dry ice particles in the dry ice particle-compressed air mixture. According to implementations of the last-mentioned embodiment, the conditioning unit is designed to preferably automatically and even more preferably optionally automatically condition the dry ice particle-compressed air mixture in such a way that preferably optionally the distance of the sublimation area from the surface to be treated:

1. (a) ten to six times the mean diameter of the dry ice particles in the dry ice particle-compressed air mixture; or
2. (b) corresponds to six to four times and in particular 4.5 times the average diameter of the dry ice particles in the dry ice particle-compressed air mixture; or
3. (c) less than four times the mean diameter of the dry ice particles in the dry ice particle-compressed air mixture; or
4. (d) at least five times the mean diameter of the dry ice particles in the dry ice particle-compressed air mixture.

In this context, it is particularly conceivable that an interface device is provided for the preferably manual selection and adjustment of one of the distance ranges (a) to (d). In this case, it is advisable for the interface device to be arranged on a spray gun for applying the conditioned dry ice particle-compressed air mixture to the surface to be treated.

Because the conditioning unit is designed to preferably automatically and even more preferably optionally automatically adjust the distance of the sublimation area from the surface to be treated as a function of an average size and in particular as a function of an average diameter of the By setting dry ice particles in the dry ice particle-compressed air mixture, the sublimation effect used for surface treatment and in particular surface cleaning can be selected in a particularly gentle manner and in a way that is particularly specific to the application. The sublimation effect is at its lowest (and thus also the material load on the surface to be treated) when the distance of the sublimation area from the surface to be treated corresponds to ten to six times the average diameter of the dry ice particles in the dry ice particle-compressed air mixture.

On the other hand, if the distance between the sublimation area and the surface to be treated is less than four times the average diameter of the dry ice particles in the dry ice particle-compressed air mixture, the surface to be treated lies completely in the sublimation area, i.e. in the area of volume expansion of the dry ice particles during the sublimation process. In this way, a particularly intensive, but nevertheless material-friendly surface treatment is possible.

According to further developments of the device, it is provided in particular that the compressed air source of the device is designed to supply a predetermined or definable amount of compressed air to the mixing unit per unit of time, wherein the amount of compressed air supplied to the mixing unit per unit of time depends in particular on an amount of dry ice particles supplied to the mixing unit per unit of time. In this way, the jet pressure of the dry ice particle-compressed air mixture can be variably adjusted and in particular selected such that an undesirable coating is removed from the surface to be treated without damaging the underlying layer.

In order to enable particularly variable and fine adjustment of the jet pressure, according to further developments of the last-mentioned embodiment, the compressed air source is further designed to supply a predetermined or definable amount of compressed air as additional compressed air to the dry ice particle-compressed air mixture per unit of time. This additional compressed air serves as transport air, whereby the amount of additional compressed air supplied to the dry ice particle-compressed air mixture per unit of time is in particular independent of the amount of dry ice particles supplied to the mixing unit per unit of time.

According to preferred implementations, the conditioning unit is particularly designed to control or regulate the amount of additional compressed air supplied per unit of time from the compressed air source of the mixing unit and/or the amount of additional compressed air supplied per unit of time from the compressed air source such that the total pressure and/or the dynamic and/or static pressure of the dry ice particle-compressed air mixture at the predetermined or definable distance in front of the surface to be treated can be variably adjusted in a range between 0.1 bar and 24 bar.

In a further development of the device, the compressed air source is further designed to supply additional compressed air to the dry ice particle-compressed air mixture, which is not primarily used as additional transport compressed air, but rather as shaping air. For example, it is conceivable that the dry ice particle-compressed air mixture is surrounded as a core jet by a sheath flow of shaping air. In this context, it is particularly conceivable that the temperature of the shaping air is different from the temperature of the dry ice particle-compressed air mixture, i.e. different from the core jet. In particular, the sheath flow (which is formed by the shaping air) can have a temperature of +20 °C to +80 °C, in particular from +60 °C to +80 °C. This allows the surface to be treated to be heated.

Heating the surface to be treated as needed can have significant advantages in surface treatment, as the heat capacity is not cooled or only slightly cooled by the heat extraction due to the core jet when the dry ice particles transition from the solid to the gaseous state. In this context, it is therefore sensible for the sheath flow to parallelize or focus the dry ice particle-compressed air mixture, which preferably has a temperature between -10 °C and -130 °C, in order to enable particularly efficient and targeted surface treatment.

1. (i) ein Abstand der Sprühpistole zu der zu behandelnden Oberfläche;
2. (ii) eine Geschwindigkeit des konditionierten Trockeneispartikel-Druckluftgemisches am Düsenauslass der Sprühpistole;
3. (iii) einen Gesamtdruck und/oder statischen und/oder dynamischen Druck des konditionierten Trockeneispartikel-Druckluftgemisches am Düsenauslass der Sprühpistole; und/oder
4. (iv) eine Temperatur des konditionierten Trockeneispartikel-Druckluftgemisches am Düsenauslass der Sprühpistole.

According to implementations of the device, it has at least one manual or automatic spray gun for applying the conditioned dry ice particle-compressed air mixture to the surface to be treated. In this context, it is conceivable that the at least one A corresponding sensor system is assigned to the spray gun, with which at least one of the following application-specific parameters can preferably be automatically recorded:

1. (i) a distance of the spray gun from the surface to be treated;
2. (ii) a velocity of the conditioned dry ice particle-compressed air mixture at the nozzle outlet of the spray gun;
3. (iii) a total pressure and/or static and/or dynamic pressure of the conditioned dry ice particle-compressed air mixture at the nozzle outlet of the spray gun; and/or
4. (iv) a temperature of the conditioned dry ice particle-compressed air mixture at the nozzle outlet of the spray gun.

• eine mittlere Größe und insbesondere einen mittleren Durchmesser der Trockeneispartikel in dem Trockeneispartikel-Druckluftgemisch;
• eine Geschwindigkeit des Trockeneispartikel-Druckluftgemisches;
• einen Gesamtdruck und/oder statischen und/oder dynamischen Druck des Trockeneispartikel-Druckluftgemisches;
• eine Temperatur des Trockeneispartikel-Druckluftgemisches; und/oder
• einen Anteil der Trockeneispartikel in dem Trockeneispartikel-Druckluftgemisch.

In a preferred development of the last-mentioned embodiment, the device according to the invention has at least one control or regulating device which is designed to control the conditioning unit, the dry ice source and/or the compressed air source in such a way that, depending on at least one parameter detected by the sensor system, at least one of the following parameters of the dry ice particle-compressed air mixture can preferably be set automatically and in a regulated manner:

• an average size and in particular an average diameter of the dry ice particles in the dry ice particle-compressed air mixture;
• a speed of the dry ice particle-compressed air mixture;
• a total pressure and/or static and/or dynamic pressure of the dry ice particle-compressed air mixture;
• a temperature of the dry ice particle-compressed air mixture; and/or
• a proportion of dry ice particles in the dry ice particle-compressed air mixture.

1. (i) zwischen 10 % bis 90 % aller im Trockeneispartikel-Druckluftgemisch enthaltenen Trockeneispartikel entspricht; oder
2. (ii) zwischen 20 % bis 80 % aller im Trockeneispartikel-Druckluftgemisch enthaltenen Trockeneispartikel entspricht; oder
3. (iii) zwischen 30 % bis 70 % aller im Trockeneispartikel-Druckluftgemisch enthaltenen Trockeneispartikel entspricht; oder
4. (iv) zwischen 40 % bis 60 % aller im Trockeneispartikel-Druckluftgemisch enthaltenen Trockeneispartikel entspricht.

Finally, according to embodiments of the present invention, the predetermined or determinable proportion of dry ice particles in the dry ice particle-compressed air mixture is preferably adjustable such that the proportion:

1. (i) corresponds to between 10% and 90% of all dry ice particles contained in the dry ice particle/compressed air mixture; or
2. (ii) corresponds to between 20% and 80% of all dry ice particles contained in the dry ice particle/compressed air mixture; or
3. (iii) corresponds to between 30% and 70% of all dry ice particles contained in the dry ice particle/compressed air mixture; or
4. (iv) corresponds to between 40% and 60% of all dry ice particles contained in the dry ice particle/compressed air mixture.

In summary, it can be said that the device can automatically or optionally automatically adjust all the parameters essential for the treatment and in particular the cleaning of surfaces in such a way that the treatment is particularly efficient and targeted, but still extremely gentle on the material. In this way, the dry ice treatment process can also be used, for example, in semiconductor production or in the treatment of open-pored, relatively sensitive surfaces.

The invention further relates to a method for treating surfaces, in particular for cleaning and/or finishing surfaces, using a device of the type according to the invention. According to the invention, the method for cleaning and/or finishing surfaces comprises the following method steps:
A dry ice particle-compressed air mixture is provided and conditioned to application-specific conditions, whereby the conditioned dry ice particle-compressed air mixture is then applied to the surface to be treated. In particular, it is provided that the dry ice particle-compressed air mixture provided is conditioned in such a way that a predetermined or definable proportion of the dry ice particles in the dry ice particle-compressed air mixture completely sublimated at a predetermined or definable distance in front of the surface to be treated, wherein for this purpose the distance of a sublimation region from the surface to be treated is preferably automatically and even more preferably optionally automatically adjusted in an application-specific manner, wherein the sublimation region is a region in which the predetermined or definable proportion of the dry ice particles in the dry ice particle-compressed air mixture completely sublimates.

An exemplary embodiment of the device according to the invention is described in more detail below with reference to the drawings.

FIG. 1a-c

schematisch das erfindungsgemäße Verfahren zur Behandlung von Oberflächen, insbesondere zur Reinigung und/oder Veredelung von Oberflächen; und

FIG. 2

schematisch eine exemplarische Ausführungsform der erfindungsgemäßen Vorrichtung zur Behandlung von Oberflächen, insbesondere zur Reinigung und/oder Veredelung von Oberflächen.

Show it:

FIG. 1a-c

schematically the method according to the invention for treating surfaces, in particular for cleaning and/or finishing surfaces; and

FIG. 2

schematically an exemplary embodiment of the device according to the invention for treating surfaces, in particular for cleaning and/or finishing surfaces.

In the FIG. 2 The schematically shown exemplary embodiment of the device 1 according to the invention has a dry ice source 2 for providing dry ice, in particular in the form of dry ice particles, a compressed air source 4 and a mixing unit 3, wherein the mixing unit 3 is fluidly connected to the dry ice source 2 on the one hand and the compressed air source 4 on the other hand and serves to generate a dry ice particle-compressed air mixture 14 from the dry ice provided by the dry ice source 2 and the compressed air provided by the compressed air source 4.

According to the invention, a conditioning unit 5 is also used, with which a dry ice particle-compressed air mixture 14 provided or to be provided by the mixing unit 3 can be adapted to application-specific conditions before the dry ice particle-compressed air mixture 14 is applied to the surface to be treated.

In the FIG. 2 The schematically shown dry ice source 2 may comprise a device 1 for generating solid CO2 particles, said device 1 comprising, for example, a snow chamber having an inlet for CO2 and a compressor for compressing CO2 snow located in the snow chamber. In this context, it is conceivable that the snow chamber is closed on one side by a matrix provided with openings.

Alternatively, it is also conceivable that the dry ice source 2 of the device 1 according to the invention has a storage container for storing dry ice particles the size of a grain of rice, so-called CO2 pellets.

The CO2 pellets are produced by taking liquid carbon dioxide from an insulated tank, in which the carbon dioxide is stored at a pressure of between 12 and 22 bar, and expanding it to atmospheric pressure via nozzles in a snow chamber. When the liquid carbon dioxide is expanded, a mixture of CO2 snow and cold CO2 gas is created. The gas phase is separated from the CO2 snow and the CO2 snow is compressed using a compressor. A piston compressor, for example, is used for this. The resulting dry ice block is then pressed through a die to produce solid CO2 strands, which are then cut into pellets about the size of a grain of rice using a suitable breaking tool.

The dry ice particles provided by the dry ice source 2, such as dry ice pellets, are metered into a compressed air stream provided by the compressed air source 4 in the mixing unit 3 and conveyed with this to a jet nozzle. In the device 1 according to the invention, the compressed air stream has a pressure between 0.1 bar and 24 bar, while the dry ice particles (CO2 pellets) are at atmospheric pressure. A pressure lock is preferably used to meter the dry ice particles into the compressed air stream, which is shown in the schematic drawing according to FIG. 2 is not shown.

When applying the dry ice particle-compressed air mixture 14 generated in the mixing unit 3 of the device 1 according to the invention to the surface 12 to be treated, the dry ice particles in the dry ice particle-compressed air mixture 14 are accelerated with the aid of the compressed air provided by the compressed air source 4, and the dry ice particle compressed air flow is - as in FIG. 1a indicated - directed towards the surface 12 to be cleaned or treated.

According to the invention, it is provided in this context that the dry ice particle-compressed air mixture 14 is conditioned with the aid of the conditioning unit 5 in such a way that a predetermined or definable proportion of the dry ice particles in the dry ice particle-compressed air mixture 14 completely sublimates at a predetermined or definable distance in front of the surface 12 to be treated. This so-called sublimation area 15, ie the area in which the predetermined or definable proportion of the dry ice particles in the dry ice particle-compressed air mixture 14 completely sublimates, is in FIG. 1a indicated accordingly.

In this context, it is particularly provided that not only the proportion of dry ice particles in the dry ice particle-compressed air mixture 14, which completely sublimates in the sublimation region 15, but also the distance of the sublimation region 15 from the surface 12 to be treated is preferably variably adjustable.

Thus, according to implementations of the device 1, it is provided that the predetermined or definable proportion of dry ice particles in the dry ice particle-compressed air mixture 14 is preferably adjustable such that the proportion corresponds to between 10% and 90% of all dry ice particles contained in the dry ice particle-compressed air mixture 14, or between 20% and 80% of all dry ice particles contained in the dry ice particle-compressed air mixture 14, or between 30% and 70% of all dry ice particles contained in the dry ice particle-compressed air mixture 14, or between 40% and 60% of all dry ice particles contained in the dry ice particle-compressed air mixture 14.

Of course, other ranges for the proportion of dry ice particles are also conceivable.

With regard to the distance of the sublimation area 15 from the surface 12 to be treated, according to the exemplary embodiment of the device 1 according to the invention, it is provided that the conditioning unit 5 is designed to preferably automatically and even more preferably optionally automatically condition the dry ice particle-compressed air mixture 14 in such a way that optionally the distance of the sublimation area 15 from the surface to be treated 12 corresponds to ten to six times the average diameter of the dry ice particles in the dry ice particle-compressed air mixture 14, or corresponds to six to four times and in particular 4.5 times the average diameter of the dry ice particles in the dry ice particle-compressed air mixture 14, or corresponds to less than four times the average diameter of the dry ice particles in the dry ice particle-compressed air mixture 14, or corresponds to at least five times the average diameter of the dry ice particles in the dry ice particle-compressed air mixture 14.

In particular, it is thus provided that the distance of the sublimation region 15 from the surface 12 to be treated can be adjusted with the aid of the conditioning unit 5 as a function of an average size and in particular as a function of an average diameter of the dry ice particles in the dry ice particle-compressed air mixture 14.

The distance of the sublimation region 15 is in particular variably adjustable by varying the average size and in particular the average diameter of the dry ice particles in the dry ice particle-compressed air mixture 14 and/or by varying the amount of compressed air supplied per unit of time from the compressed air source 4 to the mixing unit 3 accordingly.

To adjust the average size of the dry ice particles in the dry ice particle-compressed air mixture 14, the device 1 according to the invention has FIG. 2 a filtration device 7, wherein the dry ice particle-compressed air mixture 14 to be conditioned is passed through this filtration device 7, and wherein the filtration device 7 is designed to allow only dry ice particles with a particle size that does not exceed a predetermined or definable value to pass through.

In this context, the invention provides that a mesh size of the filtration device 7 is adjustable in order to be able to set a critical particle size of the dry ice particles in the dry ice particle-compressed air mixture 14.

The compressed air source 4 of the device 1 serves not only to supply a predetermined or definable amount of compressed air per unit of time Mixing unit 3, wherein the amount of compressed air supplied to mixing unit 3 per unit of time depends in particular on an amount of dry ice particles supplied to mixing unit 3 per unit of time, but also to meter a predetermined or definable amount of compressed air as additional compressed air 8 per unit of time to the dry ice particle-compressed air mixture 14 generated by mixing unit 3. This additional compressed air 8 serves in particular to vary the jet pressure and/or to adjust a speed of the dry ice particle-compressed air mixture 14.

According to further developments of the device 1, the compressed air source 4 is further designed to supply shaping air 9 to a manual or automatic spray gun 6, which serves to apply the conditioned dry ice particle-compressed air mixture 14 to the surface 12 to be treated, in order to form, for example, an enveloping flow which envelops the dry ice particle-compressed air mixture 14 and has a parallelizing or focusing effect.

1. (i) einen Abstand der Sprühpistole 6 zu der zu behandelnden Oberfläche 12;
2. (ii) eine Geschwindigkeit des konditionierten Trockeneispartikel-Druckluftgemisches 14 am Düsenauslass der Sprühpistole 6;
3. (iii) einen Gesamtdruck und/oder statischen und/oder dynamischen Druck des konditionierten Trockeneispartikel-Druckluftgemisches 14 am Düsenauslass der Sprühpistole 6; und/oder
4. (iv) eine Temperatur des konditionierten Trockeneispartikel-Druckluftgemisches 14 am Düsenauslass der Sprühpistole 6.

The spray gun 6 can - as in FIG. 2 indicated - have a corresponding sensor system 10 to preferably automatically detect at least one of the following application-specific parameters:

1. (i) a distance of the spray gun 6 from the surface 12 to be treated;
2. (ii) a velocity of the conditioned dry ice particle-compressed air mixture 14 at the nozzle outlet of the spray gun 6;
3. (iii) a total pressure and/or static and/or dynamic pressure of the conditioned dry ice particle-compressed air mixture 14 at the nozzle outlet of the spray gun 6; and/or
4. (iv) a temperature of the conditioned dry ice particle-compressed air mixture 14 at the nozzle outlet of the spray gun 6.

• eine mittlere Größe und insbesondere einen mittleren Durchmesser der Trockeneispartikel in dem Trockeneispartikel-Druckluftgemisch;
• eine Geschwindigkeit des Trockeneispartikel-Druckluftgemisches 14;
• einen Gesamtdruck und/oder statischen und/oder dynamischen Druck des Trockeneispartikel-Druckluftgemisches 14;
• eine Temperatur des Trockeneispartikel-Druckluftgemisches 14; und/oder
• einen Anteil der Trockeneispartikel in dem Trockeneispartikel-Druckluftgemisch.

Advantageously, the device 1 has a FIG. 2 not explicitly shown control or regulating device, which is designed to control the conditioning unit 5, the dry ice source 2 and/or the compressed air source 4 in such a way, that depending on at least one parameter detected by the sensor system 10, at least one of the following parameters of the dry ice particle-compressed air mixture 14 is preferably adjustable in a control manner:

• an average size and in particular an average diameter of the dry ice particles in the dry ice particle-compressed air mixture;
• a speed of the dry ice particle-compressed air mixture 14;
• a total pressure and/or static and/or dynamic pressure of the dry ice particle-compressed air mixture 14;
• a temperature of the dry ice particle-compressed air mixture 14; and/or
• a proportion of dry ice particles in the dry ice particle-compressed air mixture.

As already explained, the method according to the invention provides that a predetermined or definable proportion of the dry ice particles in the dry ice particle-compressed air mixture 14 is completely sublimated at a predetermined or definable distance in front of the surface 12 to be treated (= sublimation area 15). In this way, the surface 12 to be treated is protected as much as possible, since the dry ice particles in the dry ice particle-compressed air mixture 14 no longer, or at least for the most part, no longer impact the surface 12 to be treated.

Nevertheless, as in FIG. 1b and 1c As shown, the method according to the invention results in optimum cleaning or treatment of the surface 12, since the sublimation region 15 is preferably selected such that - although the dry ice particles no longer directly impinge on the surface 12 - the low temperature of the sublimated dry ice leads to cracking of the coating 13 on the surface 12 to be treated and thus leads to the detachment of the coating 13.

In addition, the sublimation area 15 is preferably selected in the immediate vicinity of the surface 12, so that due to the sublimation effect or is cleaned due to the explosive effect when the dry ice particles sublimate.

List of reference symbols

1

Dry ice treatment device

2

Dry ice source

3

Mixing unit

4

Compressed air source

5

Conditioning unit

6

Spray gun

7

Filtration device

8th

Additional compressed air

9

Forming air

10

Sensor technology

11

Dry ice particle-compressed air mixture

12

surface

13

coating to be removed (contamination)

14

Dry ice particle-compressed air mixture

15

Sublimation area

Claims (12)

1. A device (1) for dry ice treatment and in particular for dry ice cleaning of surfaces (12), wherein the device (1) comprises the following:

   - a dry ice source (2) for providing dry ice, particularly in the form of dry ice particles;

   - a mixing unit (3) fluidly connected or connectable to the dry ice source (2);

   - a compressed air source (4) fluidly connected or connectable to the mixing unit (3); and

   - a conditioning unit (5) fluidly connected or connectable to the mixing unit (3) for adapting a dry ice particle/compressed air mixture (11) provided by the mixing unit (3) to application-specific conditions prior to the dry ice particle/compressed air mixture (11) being applied to the surface (12) to be treated,

   wherein the conditioning unit (5) is designed to condition the dry ice particle/compressed air mixture (11) such that a predefined or definable portion of dry ice particles in the dry ice particle/compressed air mixture (11) is completely sublimated at a predefined or definable distance in front of the surface (12) to be treated,

   wherein the distance of a sublimation range (15) from the surface (12) to be treated can to that end be set in an application-specific manner, preferably automatically and more preferentially selectively automatically, by means of the conditioning unit (5), wherein the sublimation range (15) is an area in which the predefined or definable portion of dry ice particles in the dry ice particle/compressed air mixture (11) is completely sublimated,

   wherein the conditioning unit (5) comprises at least one filtration device (7), wherein at least part of the dry ice particle/compressed air mixture (11) to be conditioned is directed through the filtration device (7), and wherein the filtration device (7) is designed to only allow dry ice particles of a particle size not exceeding a predefined or definable value to pass through, characterized in that

   a mesh size of the filtration device (7) is adjustable for setting a critical particle size of the dry ice particles in the dry ice particle/compressed air mixture (11) up to which dry ice particles pass through the filtration device (7).
2. The device (1) according to claim 1,
   wherein the conditioning unit (5) is designed to preferably automatically and more preferentially selectively automatically set the distance of the sublimation range (15) from the surface (12) to be treated as a function of average size and in particular as a function of average diameter of the dry ice particles in the dry ice particle/compressed air mixture (11).
3. The device (1) according to claim 1 or 2,
   wherein the conditioning unit (5) is designed to preferably automatically and more preferentially selectively automatically condition the dry ice particle/ compressed air mixture (11) such that the distance of the sublimation range (15) from the surface (12) to be treated preferably selectively corresponds to:

   (a) ten to six times the average diameter of the dry ice particles in the dry ice particle/compressed air mixture (11); or

   (b) six to four times and in particular 4.5 times the average diameter of the dry ice particles in the dry ice particle/compressed air mixture (11); or

   (c) less than four times the average diameter of the dry ice particles in the dry ice particle/compressed air mixture (11); or

   (d) at least five times the average diameter of the dry ice particles in the dry ice particle/compressed air mixture (11).
4. The device (1) according to claim 3,
   wherein an interface device is provided for preferably manually selecting and setting one of the distance ranges (a) to (d), wherein the interface device is preferably arranged on a spray gun (6) for applying the conditioned dry ice particle/compressed air mixture (11) to the surface (12) to be treated.
5. The device (1) according to one of claims 1 to 4,
   wherein the conditioning unit (5) is designed to preferably automatically and more preferentially selectively automatically set an average size and in particular an average diameter of the dry ice particles in the dry ice particle/ compressed air mixture (11), particularly in application-specific manner.
6. The device (1) according to one of claims 1 to 5,
   wherein the compressed air source (4) is designed to supply a predefined or definable amount of compressed air to the mixing unit (3) per unit of time, wherein the amount of compressed air supplied to the mixing unit (3) per unit of time particularly depends on an amount of dry ice particles supplied to the mixing unit (3) per unit of time.
7. The device (1) according to claim 6,
   wherein the compressed air source (4) is further designed to supply a predefined or definable amount of compressed air to the dry ice particle/ compressed air mixture (11) per unit of time as additional compressed air.
8. The device (1) according to claim 6 or 7,
   wherein the conditioning unit (5) is designed to control or regulate the amount of additional compressed air supplied to the mixing unit (3) per unit of time from the compressed air source (4) and/or the amount of additional compressed air supplied per unit of time from the compressed air source (4) such that the dynamic and/or static pressure of the dry ice particle/ compressed air mixture (11) in the predefined or definable distance in front of the surface (12) to be treated is variably adjustable in a range of between 0.1 bar to 24 bar.
9. The device (1) according to one of claims 1 to 8,
   wherein the predefined or definable portion of dry ice particles in the dry ice particle/compressed air mixture (11) is preferably adjustable such that the portion corresponds to:

   (i) between 10% to 90% of all the dry ice particles contained in the dry ice particle/compressed air mixture (11); or

   (ii) between 20% to 80% of all the dry ice ice particles contained in the dry ice particle/compressed air mixture (11); or

   (iii) between 30% to 70% of all the dry ice ice particles contained in the dry ice particle/compressed air mixture (11); or

   (iv) between 40% to 60% of all the dry ice ice particles contained in the dry ice particle/compressed air mixture (11).
10. The device (1) according to one of claims 1 to 9,
    wherein the device (1) comprises at least one manual or automatic spray gun (6) for applying the conditioned dry ice particle/compressed air mixture (11) to the surface (12) to be treated (12), wherein the device (1) further comprises a sensor system allocated to the at least one spray gun (6) for preferably automatically detecting at least one of the following, in particular application-specific, parameters:

    (i) a distance of the spray gun (6) to the surface (12) to be treated;

    (ii) a speed of the conditioned dry ice particle/compressed air mixture (11) at the nozzle outlet of the spray gun (6);

    (iii) a static and/or dynamic pressure of the conditioned dry ice particle/compressed air mixture (11) at the nozzle outlet of the spray gun (6); and/or

    (iv) a temperature of the conditioned dry ice particle/compressed air mixture (11) at the nozzle outlet of the spray gun (6).
11. The device (1) according to claim 10,
    wherein the device (1) comprises at least one control or regulating device which is designed to control the conditioning unit (5), the dry ice source (2) and/or the compressed air source (4) such that at least one of the following parameters of the dry ice particle/compressed air mixture (11) is preferably controllably adjustable as a function of at least one parameter detected by means of the sensor system:

    - an average size and particularly an average diameter of the dry ice particles;

    - a speed of the dry ice particle/compressed air mixture (11);

    - a static and/or dynamic pressure of the dry ice particle/compressed air mixture (11);

    - a temperature of the dry ice particle/compressed air mixture (11); and/or

    - a portion of dry ice particles in the dry ice particle/compressed air mixture.
12. A method for treating surfaces (12), in particular for cleaning and/or refining surfaces (12), and wherein the method comprises the following method steps:

    - providing a dry ice particle/compressed air mixture (11);

    - conditioning the provided dry ice particle/compressed air mixture (11) to application-specific conditions; and

    - applying the conditioned dry ice particle/compressed air mixture (11) to the surface (12) to be treated,

    wherein the provided dry ice particle/compressed air mixture (11) is conditioned such that a predefined or definable portion of dry ice particles in the dry ice particle/compressed air mixture (11) is completely sublimated at a predefined or definable distance in front of the surface (12) to be treated, wherein the distance of a sublimation range (15) from the surface (12) to be treated can to that end be set in an application-specific manner, preferably automatically and more preferentially selectively automatically, wherein the sublimation range (15) is an area in which the predefined or definable portion of dry ice particles in the dry ice particle/compressed air mixture (11) is completely sublimated,

    wherein the method is characterized in that a device (1) according to one of claims 1 to 11 is used thereto.

Images