Cleaning device

Abstract

The invention relates to a cleaning device for applying surfaces to be treated with a mixed stream formed of a pressurised gas and CO2 pellets, comprising a device for producing CO2 pellets from liquid or gaseous CO2, wherein the device comprises a compression unit for compressing CO2 snow to form the CO2 pellets, wherein the compression unit comprises an expansion unit for generating CO2 snow by expanding liquid or pressurised CO2, wherein the expansion unit comprises an expansion chamber with an expansion chamber inlet, wherein the cleaning device comprises a CO2 connection line fluidically connected to the expansion chamber inlet for supplying the liquid or gaseous CO2 to the expansion unit and wherein the cleaning device comprises a cooling unit for cooling the CO2 connection line.

Description

[0001] cleaning device

[0002] The present invention relates to a cleaning device for irradiating surfaces to be treated with a mixture stream of a compressed gas and CO2 pellets, comprising a device for producing CO2 pellets from liquid or gaseous CO2, wherein the device comprises a compression device for compressing CO2 snow to form the CO2 pellets, wherein the compression device comprises an expansion device for producing CO2 snow by expanding liquid or pressurized CO2, wherein the expansion device comprises an expansion chamber with an expansion chamber inlet and wherein the cleaning device has a CO2 connection line fluidly connected to the expansion chamber inlet for supplying the liquid or gaseous CO2 to the expansion device.

[0003] A cleaning device of the type described above is known, for example, from WO 2015 / 079022 A1. This cleaning device makes it possible to produce CO2 pellets, also known as dry ice pellets, from liquid CO2.

[0004] A particular problem with such known purification devices is the limited yield of CO2 pellets that can be produced from a given amount of liquid CO2.

[0005] It is therefore an object of the present invention to improve the efficiency of the cleaning device.

[0006] This object is achieved according to the invention in a cleaning device of the type described above in that the cleaning device comprises a cooling device for cooling the CO2 connection line. The further development proposed according to the invention makes it possible, in particular, to improve the efficiency of the cleaning device, i.e. in particular to increase the yield of CO2 pellets from a predetermined amount of liquid CO2. The cooling device allows the input product of the cleaning device, i.e. pressurized gaseous or liquid CO2, to be cooled. The colder the gaseous or liquid CO2, the more efficiently it can be used in the subsequent process. Therefore, the colder the gaseous or liquid CO2 used for this purpose, the more CO2 snow can be formed. The cooling device can here in particular be an active cooling device which cools the CO2 connection line.For example, the cooling system can be powered by electricity.

[0007] To increase the efficiency of the cleaning device, the cooling device can also be designed in the form of a passive cooling device. This has the particular advantage that no additional energy is required to cool the CO2 connection line. For example, the passive cooling device can be designed in the form of a countercurrent cooling device. For example, a cool exhaust gas from the cleaning device, such as cool CO2, can be used to cool the CO2 connection line. However, with the countercurrent cooling device, direct contact between the medium to be cooled, i.e. the liquid or gaseous CO2 on the one hand, and the cooling medium is prevented. Alternatively, any other sufficiently cool gas or liquid flow can be used as the cooling medium.The cooling device makes it possible, in particular, to pre-cool liquid CO2 from bottles that are not pre-conditioned, in order to produce as much CO2 snow as possible when the liquid or gaseous CO2 is released.

[0008] The cleaning device can be designed in a simple manner if the cooling device includes a heat exchanger and if the CO2 connection line extends through the heat exchanger. This design makes it possible, in particular, to directly cool the CO2 connection line, specifically in the area where it extends through the heat exchanger. It can then be cooled directly by a fluid flowing through the heat exchanger, i.e., a liquid or gas stream with a correspondingly low temperature.

[0009] It is advantageous if the heat exchanger comprises a cooling channel with a cooling channel inlet and a cooling channel outlet, and if the CO2 connecting line extends through the cooling channel. In particular, a connecting line section of the CO2 connecting line can extend through the cooling channel. Therefore, it is not absolutely necessary for the entire CO2 connecting line to be cooled; it is sufficient if at least one connecting line section of the CO2 connecting line is cooled.

[0010] It is advantageous if the heat exchanger has an inlet side and an outlet side, if the cooling channel inlet is arranged or formed on the inlet side, and if the cooling channel outlet is arranged or formed on the outlet side. Thus, if the inlet side and outlet side are spatially separated from each other, the cooling channel inlet and outlet can also be spatially separated from each other in a simple manner. This allows for optimal flow of a cooling fluid through the heat exchanger.

[0011] Preferably, the connecting line section extends from the outlet side through the cooling channel to the inlet side, or vice versa. Such an arrangement makes it possible, in particular, to cool the liquid or gaseous CO2 flowing through the CO2 connecting line in a countercurrent process by a cooling fluid flowing through the cooling channel.

[0012] It is advantageous if the connecting line section has a connecting line section length, if the cooling device has a cooling device length that corresponds to a distance between the inlet side and the outlet side, and if the ratio between the connecting line section length and the cooling device length is in a range from approximately 5:1 to approximately 25:1. Such a configuration makes it possible, in particular, to select or specify a heat exchanger surface that is as large as possible and optimized for heat exchange. Nevertheless, the cooling device can be designed compactly in order to achieve the smallest possible design, so that the cleaning device as a whole can retain a manageable and handy size.

[0013] For easy handling of the cleaning device, it is advantageous if the cooling channel inlet and / or the cooling channel outlet comprise a hose connection piece for fluid-tight connection to a hose. Such a design makes it particularly easy to guide a cooling fluid through a hose to the cooling device and away from it after flowing through the cooling device.

[0014] It is advantageous if the compression device comprises a CO2 exhaust outlet and if the CO2 exhaust outlet is fluidly connected to the cooling channel inlet. This configuration makes it possible, in particular, to use the gaseous CO2 emerging from the pre-compression device, which has a significantly lower temperature than the ambient temperature of the cleaning device, as a cooling medium for cooling the CO2 connecting line, in particular the connecting line section thereof. Sublimated, i.e. gaseous, CO2, which is created in the compression device, is then not only released into the environment of the cleaning device, but is initially used to pre-cool the CO2 connecting line. The cooling device can therefore be used, in particular, as a passive cooling device. No additional energy is required to cool the CO2 connecting line.Instead, a waste product from the use of the cleaning device, namely cooled gaseous CO2, is used as a cooling fluid.

[0015] It is advantageous if the cleaning device comprises a CO2 cleaning device exhaust outlet and if the cooling channel outlet is fluidly connected to the CO2 cleaning device exhaust outlet. This configuration makes it possible, in particular, to divert the gaseous CO2 from the cleaning device after flowing through the cooling device in a defined manner, for example, into its surroundings. Optionally, the CO2 cleaning device exhaust outlet can also be connected to a hose, for example to divert the gaseous CO2 produced during the CO2 pellet manufacturing process from a cleaning chamber in which a surface to be treated is exposed to a mixture of a compressed gas and CO2 pellets. In this way, the proportion of CO2 in the ambient air of the cleaning device can be controlled in a defined manner.

[0016] The cooling device preferably comprises at least one heat-conducting element that is thermally connected to the connecting line section. The at least one heat-conducting element serves, in particular, the purpose of enlarging the surface area of ​​the connecting line section in order to achieve improved heat exchange in the region of the cooling device.

[0017] The cooling device can be easily configured if the at least one heat-conducting element is in the form of a heat-conducting fin protruding from the connecting line section and / or in the form of a woven, knitted, or woolen body. The cooling medium, for example, cold gaseous CO2, can flow around the heat-conducting fins or the described woven, knitted, or woolen bodies, thereby cooling them. They are suitable for dissipating heat from the connecting line section, so that the cooling fluid flow flowing through the cooling device can absorb this heat.

[0018] It is advantageous if the at least one heat-conducting element is made of a heat-conducting body material which has a thermal conductivity of at least approximately 30 W / (m K). In particular, the thermal conductivity can be at least approximately 100 W / (m K). Heat-conducting elements made of a metallic material are particularly suitable for this purpose. For example, zinc has a thermal conductivity of approximately 110 W / (m K), aluminum of approximately 230 W / (m K). Copper has a thermal conductivity in the range of approximately 240 to 380 W / (m K). The cooling device can be formed simply and cost-effectively if the at least one heat-conducting element is made of a metallic material. Compared to plastics, metallic materials, in particular pure metals or metal alloys such as copper alloys or aluminum alloys, have a significantly higher thermal conductivity.

[0019] To increase the surface area of ​​the CO2 connecting line, it is advantageous if the connecting line section is helically shaped. In particular, it can be designed in the form of a helical coil. For this purpose, the connecting line section can be designed in the form of a tube that is wound in a helical manner.

[0020] To achieve the best possible heat transfer, it is advantageous if the connecting line section is made of a metallic material. Especially if the connecting line section is in thermal contact with at least one heat-conducting element, a cooling fluid flowing past the connecting line section can absorb heat from the connecting line section and thus cool it.

[0021] A particularly compact design of the cleaning device can be achieved in particular by the heat exchanger comprising a heat exchanger housing, and by the heat exchanger housing defining the cooling channel. The flow of a cooling medium can thus be achieved in a simple manner, in particular by passing it through the heat exchanger housing.

[0022] It is advantageous if the heat exchanger housing defines a heat exchanger housing longitudinal axis and is cylindrical or substantially cylindrical or cuboidal or substantially cuboidal. In this way, the cooling device can be designed to be particularly compact and cooling of the CO2 connection line can be optimized. For good cooling results, it is advantageous if the cooling channel inlet and / or the cooling channel outlet are arranged or designed eccentrically on the heat exchanger housing with respect to the heat exchanger housing longitudinal axis. For example, on the inlet side of the heat exchanger, the cooling channel inlet can be arranged eccentrically or coaxially to the heat exchanger housing longitudinal axis. On the inlet side, with an eccentrically arranged cooling channel inlet, the CO2 connection line can be led out of the heat exchanger housing coaxially to the heat exchanger housing longitudinal axis or likewise eccentrically relative to this.Similarly, the cooling channel outlet on the output side can be arranged eccentrically or coaxially to the longitudinal axis of the heat exchanger housing. Furthermore, with an eccentrically arranged cooling channel outlet, the CO2 connection line can be routed coaxially to the longitudinal axis of the heat exchanger housing or also eccentrically relative to it on the output side into the heat exchanger housing. In this way, optimal cooling of the connecting line section of the CO2 connection line in the heat exchanger housing can be achieved using the counterflow principle.

[0023] According to a further preferred embodiment, it can be provided that the cooling channel inlet defines a cooling channel inlet longitudinal axis, that the cooling channel outlet defines a cooling channel outlet longitudinal axis, and that the cooling channel inlet longitudinal axis and / or the cooling channel outlet longitudinal axis run parallel to the heat exchanger housing longitudinal axis. This configuration makes it possible, in particular, to guide the cooling fluid into the heat exchanger housing in a defined manner. In particular, the flow of the cooling fluid can be optimized so that heat exchange preferably takes place within the heat exchanger housing and not beforehand, i.e., outside of it.

[0024] Preferably, the cooling channel inlet longitudinal axis defines the cooling channel outlet longitudinal axis. Thus, the cooling channel inlet and the cooling channel outlet can be formed or arranged coaxially with each other on the heat exchanger. This allows, in particular, an optimized flow of the cooling fluid through the heat exchanger to be achieved.

[0025] It is advantageous if the heat exchanger housing defines a heat exchanger housing length and a heat exchanger housing diameter, and if the ratio between the heat exchanger housing length and the heat exchanger housing diameter is in a range from approximately 5:4 to approximately 5:1. In particular, the ratio can be in a range from approximately 3:2 to approximately 3:1. Such a heat exchanger is particularly compact in its design and can be easily retrofitted, for example, to cleaning devices already on the market.

[0026] It is advantageous if the heat exchanger housing has a heat exchanger housing wall that defines the cooling channel, and if the heat exchanger housing wall is thermally insulated. This can prevent the cooling medium from excessively cooling the area surrounding the heat exchanger. In other words, the cooling effect of the cooling fluid for the CO2 connection line can be improved.

[0027] For good thermal insulation of the cooling device, it is advantageous if the heat exchanger housing wall is made of a heat exchanger housing wall material that has a thermal conductivity of at most approximately 1 W / (m K). In particular, the thermal conductivity can be at most approximately 0.1 W / (m K). For example, the heat exchanger housing wall can be made of a plastic, for example based on polyethylene or polystyrene. Polyurethane can also be used as a heat exchanger housing wall material. The heat exchanger housing wall can optionally also comprise an insulating layer made of a suitable insulating material, which preferably has a thermal conductivity that does not exceed the specified limit values. Possible suitable insulating materials are, in particular, mineral wool, sheep's wool, cellulose, flax, or wood fibers.According to a further preferred embodiment, the cleaning device can comprise a CO2 connection that is connected or connectable to a CO2 source, and the CO2 connection is fluidly connected to the CO2 connection line. Such a cleaning device can, for example, be connected to a CO2 cylinder containing liquid CO2. This can then be supplied to the expansion device via the CO2 connection line.

[0028] It is advantageous if the expansion device comprises a switching device for opening and closing a fluid connection between the CO2 connection and the expansion chamber inlet, and if the switching device is arranged or formed between the cooling device and the expansion chamber inlet. Such a configuration makes it possible, in particular, to operate the expansion device in a pulsed manner, so that liquid or gaseous CO2 can only flow through the CO2 connection line when the fluid connection between the CO2 connection and the expansion chamber inlet is open. The formation of CO2 snow can thus be easily controlled with the switching device.

[0029] The following description of preferred embodiments of the invention serves to explain in more detail in conjunction with the drawings:

[0030] Figure 1: a schematic, partially broken overall view of an embodiment of a cleaning device;

[0031] Figure 2: a perspective, partially openwork overall view of the cleaning device from Figure 1 without the outer housing;

[0032] Figure 3: another perspective view of the arrangement of Figure 2;

[0033] Figure 4: an enlarged, partially broken view of a cooling device of the cleaning device; Figure 5: a sectional view along line 5-5 in Figure 4;

[0034] Figure 6: a sectional view along line 6-6 in Figure 5; and

[0035] Figure 7: a schematic representation of the structure of another embodiment of a cleaning device.

[0036] An embodiment of a cleaning device, designated overall by reference numeral 10, for irradiating surfaces to be treated with a mixed stream of a compressed gas, for example anhydrous or substantially anhydrous, i.e., dry compressed air, and CO2 pellets, is shown schematically in Figure 7. The cleaning device 10 comprises a device 12 for producing CO2 pellets from liquid or gaseous CO2.

[0037] The device 12 comprises a compression device 14 for compressing CO2 snow to form the CO2 pellets.

[0038] The compression device 14 comprises a pressure relief device 16 for generating CO2 snow by pressure relief of liquid or pressurized CO2. The pressure relief device 16 comprises a pressure relief chamber 18 with a pressure relief chamber inlet 20. Furthermore, the cleaning device 10 comprises a CO2 connection line 22 fluidly connected to the pressure relief chamber inlet 20 for supplying the liquid or gaseous CO2 to the pressure relief device 16.

[0039] To pre-cool the liquid or gaseous CO2, the cleaning device 10 includes a cooling device 24 for cooling the CO2 connection line 22. The CO2 connection line 22 is connectable or connected to a CO2 source 26. The CO2 source can be, in particular, a CO2 cylinder 28 containing liquid CO2 or a CO2 compressed gas source.

[0040] In the embodiment of the cleaning device 10 shown in Figure 7, the cooling device 24 is optionally designed in the form of an active cooling device 24, to which energy must be supplied for cooling the CO2 connection line 22, for example electrical energy, or in the form of a passive cooling device 24, which is explained in more detail below in connection with the embodiment shown in Figures 1 to 6.

[0041] Figures 1 to 6 show a further embodiment of a cleaning device 10 for irradiating surfaces to be treated with a mixed stream of a compressed gas and CO2 pellets. This embodiment of the cleaning device 10 also includes a device 12 for producing CO2 pellets from liquid or gaseous CO2.

[0042] The device 12 comprises a compression device 14 for compressing CO2 snow to form the CO2 pellets.

[0043] The compression device 14 includes a decompression device 16 for generating CO2 snow by decompressing liquid or pressurized CO2. The decompression device 16 includes a decompression chamber 18 in the form of a tube 30 bent at 90°.

[0044] The expansion chamber 18 comprises an expansion chamber inlet 20, at which an expansion nozzle (not shown in the figures) is arranged, through which liquid or pressurized gaseous CO2 can be introduced into the expansion chamber 18. The expansion chamber 18 forms part of a pre-compression device 32, in which CO2 snow is pre-compressed and then fed to the main compression device 36, designed in the form of a gear compressor 34.

[0045] A pellet transfer device 38 is connected downstream of the main compression device 36.

[0046] The pellet transfer device 38 comprises a compressed gas inlet 40, which is fluidly connected to a compressed gas connection 44 via a connecting line 42. A valve 46 is arranged on the connecting line 42 to selectively open or close the connecting line 42 to enable or interrupt a compressed gas flow.

[0047] The pellet transfer device 38 further includes a mixture flow outlet 48, which is fluidly connected to a mixture flow connection 52 via a connecting line 50. The mixture flow connection 52 can be connected via a hose to a jet nozzle, which can be guided by a user to clean or blast the surfaces to be treated with the mixture flow. For the sake of clarity, both the hose and the jet nozzle are not shown in the figures.

[0048] The compression device 14 comprises a CO2 exhaust outlet 54 from which gaseous CO2 emerges from the compression device 14, which is produced by sublimation during the production of CO2 pellets.

[0049] The cleaning device 10 further comprises a CO2 cleaning device exhaust outlet 56, which is fluidly connected to the CO2 exhaust outlet 54 via a CO2 exhaust line 58.

[0050] The cleaning device 10 further comprises a mobile frame 60 on which all components of the cleaning device 10 are arranged. This allows the cleaning device 10 to be moved easily and conveniently by a user.

[0051] A platform 62 is formed on the frame 60, on which a CO2 cylinder 28 can be positioned, as schematically shown in Figures 1 to 3. The CO2 cylinder 28 forms a CO2 source 26.

[0052] The cleaning device 10 includes a CO2 connection 64, which extends from a housing 66 of the cleaning device 10. The CO2 connection 64 can be connected to a connection 70 of the CO2 cylinder 28 via a connecting line 68. The CO2 connection 64 is thus fluidly connected to the CO2 connection line 22.

[0053] In the embodiment of Figures 1 to 6, the cooling device 24 is designed as a passive cooling device. It is implemented in the form of a countercurrent cooling device 72.

[0054] The cooling device 24 comprises a heat exchanger 74 through which the CO2 connection line 22 extends.

[0055] The heat exchanger 74 defines or comprises a cooling channel 76 with a cooling channel inlet 78 and a cooling channel outlet 80. The CO2 connection line 22, namely a connection line section 82 of the CO2 connection line 22, extends through the cooling channel 76.

[0056] The heat exchanger 74 defines an inlet side 84 and an outlet side 86, such that the cooling channel inlet 78 is arranged or formed on the inlet side 84 and that the cooling channel outlet 80 is arranged or formed on the outlet side 86.

[0057] The connecting line section 82 extends between the output side 86 and the input side 84 through the cooling channel 76.

[0058] The connecting line section 82 is helically shaped, as is schematically illustrated in particular in Figures 5 and 6. It has the shape of a helical coil 88.

[0059] The connecting line section 82 is tubular and made of a metallic material.

[0060] The heat exchanger 74 comprises a heat exchanger housing 90, which delimits and thus defines the cooling channel 76. In the embodiment illustrated in Figures 1 to 6, the heat exchanger housing 90 is cylindrical or substantially cylindrical and defines a heat exchanger housing longitudinal axis 92.

[0061] As schematically illustrated in Figure 5, both the cooling channel inlet 78 and the cooling channel outlet 80 are arranged or formed eccentrically on the heat exchanger housing 90 with respect to the heat exchanger housing longitudinal axis 92. This means, in particular, that both the cooling channel inlet 78 and the cooling channel outlet 80 are arranged or formed laterally offset on the inlet side 84 and the outlet side 86, respectively, with respect to the heat exchanger housing longitudinal axis 92.

[0062] The cooling channel inlet 78 defines a cooling channel inlet longitudinal axis 94. The cooling channel outlet 80 defines a cooling channel outlet longitudinal axis 96. In the exemplary embodiment illustrated in the figures, the cooling channel inlet longitudinal axis 94 and the cooling channel outlet longitudinal axis 96 run parallel to the heat exchanger housing longitudinal axis 92, but are laterally offset from it. In other words, the heat exchanger housing longitudinal axis 92 does not coincide with the other two axes.

[0063] In the embodiment shown in Figures 1 to 6, the cooling channel inlet longitudinal axis defines the cooling channel outlet longitudinal axis 96. Thus, the two axes are aligned with each other.

[0064] The heat exchanger housing 90 comprises a tubular housing wall 98 running concentrically to the heat exchanger housing longitudinal axis 92 as well as an end wall 100 defining the inlet side 84 and an end wall 102 defining the outlet side 86.

[0065] The cooling channel inlet 78 is designed in the form of a bore 106 in the end wall 100 provided with an internal thread 104. The cooling channel outlet 80 is designed in the form of a bore 110 in the end wall 102 provided with an internal thread 108. The cooling channel inlet 78 comprises a hose connection piece 112, which has an external thread section 114 corresponding to the internal thread 104. The hose connection piece 112 is screwed into the bore 106. An end section of the hose connection piece 112 pointing away from the end wall 100 is connected to the tubular CO2 exhaust line 58, which is in direct fluid communication with the CO2 exhaust outlet.

[0066] Another hose connection piece 116 is screwed to the bore 110 by an external thread section 118 corresponding to the internal thread 108. An end section of the hose connection piece 116 pointing away from the end wall 102 is connected to another section of the CO2 exhaust line 58, which is in direct fluid communication with the CO2 purification device exhaust outlet 56.

[0067] The heat exchanger housing 90 defines a heat exchanger housing length 120 and a heat exchanger housing diameter 122. In the embodiment illustrated in Figures 1 to 6, a ratio between the heat exchanger housing length 120 and the heat exchanger housing diameter 122 is in a range from approximately 5:4 to approximately 5:1, and more specifically in a range from approximately 3:2 to approximately 3:1.

[0068] The heat exchanger housing 90 defines a heat exchanger housing wall 124 that delimits the cooling channel 76. The heat exchanger housing wall 124 is formed by the housing wall 98 and the two end walls 100 and 102.

[0069] The heat exchanger housing wall 124 is optionally thermally insulated. It is optionally formed from a heat exchanger housing wall material having a maximum thermal conductivity of approximately 1 W / (m K). In preferred embodiments, the thermal conductivity of the heat exchanger housing wall material is approximately 0.1 W / (m K). In the embodiment illustrated in the figures, the connecting line section 82 has a connecting line section length 126. The connecting line section length 126 is defined by a length of the connecting line section 82 between the end walls 100 and 102, specifically by a center line 128 of the connecting line section 82.

[0070] The cooling device 24 defines a cooling device length 130, which corresponds to a distance 132 between the input side 84 and the output side 86.

[0071] The helical design of the connecting line section 82 results in a ratio between the connecting line section length 126 and the cooling device length 130 in a range from approximately 5:1 to approximately 25:1. In this way, a surface area of ​​the connecting line section 82 is enlarged compared to a design in which the connecting line section would extend parallel to the heat exchanger housing longitudinal axis 92 through the cooling channel 76.

[0072] To improve heat exchange between the cooling channel 76 and the gaseous CO2 flowing through it, on the one hand, and the connecting line section 82 and the liquid CO2 flowing through it, on the other hand, the cooling device 24 optionally comprises one or more heat-conducting elements 134, which are in thermal communication with the connecting line section 82. Figure 6 shows, by way of example, a heat-conducting element 134 in the form of a woven, knitted, or woolen body 136.

[0073] Figure 5 shows, alternatively and purely schematically, optional heat-conducting elements 134 in the form of heat-conducting fins 138. These also raise a surface of the connecting line section 82 in the cooling channel 76 in order to achieve heat exchange between the media flowing through the cooling channel 76 on the one hand and the connecting line section 82 on the other. The heat-conducting elements 134 are optionally formed from a metallic material.

[0074] In one embodiment, the heat-conducting elements 134 are formed from a heat-conducting material having a thermal conductivity of at least approximately 30 W / (m K). Preferably, the thermal conductivity of the heat-conducting material is at least approximately 100 W / (m K).

[0075] In order to control the inflow of liquid or pressurized CO2 through the expansion chamber inlet 20, the expansion device 16 comprises a switching device 140 for opening and closing a fluid connection between the CO2 connection 64 and the expansion chamber inlet 20. The switching device 140 comprises an electromagnetic valve 142, which is arranged in the CO2 connection line 22 in order to selectively open and close it. In the embodiment shown in Figures 1 to 6, the switching device 140 is arranged or formed between the cooling device 24 and the expansion chamber inlet 20.

[0076] The cooling device 24 allows the efficiency of producing CO2 pellets with the compression device 14 to be significantly increased, namely by over 25% compared to a cleaning device 10 that does not have a heat exchanger 74. In other words, this means that with the same content of the CO2 cylinder 28, 25% more CO2 pellets can be produced with the cleaning device 10 according to the embodiment of Figures 1 to 6, and thus, with the same CO2 pellet quality and production rate, a 25% longer treatment time for surfaces to be treated can be achieved. The CO2 cylinder 28 therefore needs to be replaced less frequently. Furthermore, the operating costs of the cleaning device 10 can be significantly reduced, thus protecting the environment. List of Reference Symbols

[0077] 10 Cleaning device

[0078] 12 Device

[0079] 14 Compaction device

[0080] 16 relaxation facilities

[0081] 18 relaxation chamber

[0082] 20 Expansion chamber inlet

[0083] 22 CO2 connection line

[0084] 24 Cooling device

[0085] 26 CO2 source

[0086] 28 CO2 bottles

[0087] 30 pipe

[0088] 32 Pre-compression device

[0089] 34 gear compressors

[0090] 36 Main compression device

[0091] 38 Pellet transfer device

[0092] 40 Compressed gas inlet

[0093] 42 connecting cable

[0094] 44 Compressed gas connection

[0095] 46 Valve

[0096] 48 Mixture flow outlet

[0097] 50 connecting cable

[0098] 52 Mixed flow connection

[0099] 54 CO2 exhaust outlet

[0100] 56 CO2 cleaning device exhaust outlet

[0101] 58 CO2 exhaust pipe

[0102] 60 frames

[0103] 62 Platform

[0104] 64 CO2 connection

[0105] 66 housings

[0106] 68 Connecting cable 70 Connection

[0107] 72 Counterflow cooling device

[0108] 74 heat exchangers

[0109] 76 Cooling channel

[0110] 78 Cooling channel inlet

[0111] 80 cooling channel outlet

[0112] 82 connecting line section

[0113] 84 Entrance page

[0114] 86 Output page

[0115] 88 screw coil

[0116] 90 heat exchanger housing

[0117] 92 Heat exchanger housing longitudinal axis

[0118] 94 Cooling channel inlet longitudinal axis

[0119] 96 Cooling channel outlet longitudinal axis

[0120] 98 Housing wall

[0121] 100 front wall

[0122] 102 front wall

[0123] 104 internal thread

[0124] 106 bore

[0125] 108 internal threads

[0126] 110 bore

[0127] 112 hose connectors

[0128] 114 External thread section

[0129] 116 hose connectors

[0130] 118 External thread section

[0131] 120 heat exchanger housing length

[0132] 122 heat exchanger housing diameter

[0133] 124 Heat exchanger housing wall

[0134] 126 Connection cable section length

[0135] 128 Center line

[0136] 130 Cooling device length

[0137] 132 distance

[0138] 134 Heat conducting element 136 Wool body

[0139] 138 Heat conducting fin

[0140] 140 switching device

[0141] 142 Valve

Claims

Patent claims 1.Cleaning device (10) for irradiating surfaces to be treated with a mixture stream of a pressurized gas and CO2 pellets, comprising a device (12) for producing CO2 pellets from liquid or gaseous CO2, wherein the device (12) comprises a compression device (14) for compressing CO2 snow to form the CO2 pellets, wherein the compression device (14) comprises a decompression device (16) for producing CO2 snow by decompressing liquid or pressurized CO2, wherein the decompression device (16) comprises a decompression chamber (18) with a decompression chamber inlet (20), and wherein the cleaning device (10) comprises a CO2 supply line (22) fluidly connected to the decompression chamber inlet (20) for supplying the liquid or gaseous CO2 to the decompression device (16), characterized in that the cleaning device (10) a cooling device (24) includes for cooling the CO2 connection line (22).

2. Cleaning device according to claim 1, characterized in that the cooling device (24) is designed in the form of a passive cooling device (24), in particular in the form of a counterflow cooling device (72).

3. Cleaning device according to any one of the preceding claims, characterized in that the cooling device (24) comprises a heat exchanger (74) and that the CO2 connection line (22) extends through the heat exchanger (74).

4. Cleaning device according to claim 3, characterized in that the heat exchanger (74) comprises a cooling channel (76) with a cooling channel inlet (78) and a cooling channel outlet (80) and that the CO2 connection line (22), in particular a connection line section (82) thereof, extends through the cooling channel (76).

5. Cleaning device according to claim 4, characterized in that the heat exchanger (74) has an inlet side (84) and an outlet side (86), and that the cooling channel inlet (78) is arranged or formed on the inlet side (84), and that the cooling channel outlet (86) is arranged or formed on the outlet side (86).

6. Cleaning device according to claim 5, characterized in that the connecting line section (82) extends from the outlet side (86) through the cooling channel (76) to the inlet side (84), or vice versa. 7.Cleaning device according to claim 5 or 6, characterized in that the connecting line section (82) has a connecting line section length (126), that the cooling device (24) has a cooling device length (130) which corresponds to a distance (132) between the inlet side (84) and the outlet side (86), and that the ratio between the connecting line section length (126) and the cooling device length (130) is in a range of approximately 5:1 to approximately 25:

1.

8. Cleaning device according to any one of claims 4 to 7, characterized in that the cooling channel inlet (78) and / or the cooling channel outlet (80) comprise a hose connection nozzle (112, 116) for fluid-tight connection with a hose (58).

9. Cleaning device according to one of claims 4 to 8, characterized in that the compression device (14) comprises a CO2 exhaust gas outlet (54) and that the CO2 exhaust gas outlet (54) is fluidly connected to the cooling channel inlet (78).

10. Cleaning device according to any one of claims 4 to 9, characterized in that the cleaning device (10) comprises a CO2 cleaning device exhaust outlet (56) and that the cooling channel outlet (80) is fluidly connected to the CO2 cleaning device exhaust outlet (56).

11. Cleaning device according to any one of claims 4 to 10, characterized in that the cooling device (24) comprises at least one heat-conducting element (134) which is in thermal contact with the connecting line section (136).

12. Cleaning device according to claim 11, characterized in that the at least one heat-conducting element (134) is designed in the form of a heat-conducting fin (138) projecting from the connecting line section (82) and / or in the form of a woven, knitted, or woolen body (136). 13.Cleaning device according to claim 11 or 12, characterized in that the at least one heat-conducting element (134) is made of a heat-conducting material having a thermal conductivity of at least approximately 30 W / (m K), in particular at least approximately 100 W / (m K).

14. Cleaning device according to any one of claims 11 to 13, characterized in that the at least one heat-conducting element (134) is made of a metallic material.

15. Cleaning device according to any one of claims 4 to 14, characterized in that the connecting cable section (82) is coiled, in particular in the form of a screw coil (88).

16. Cleaning device according to any one of claims 4 to 15, characterized in that the connecting cable section (82) is made of a metallic material.

17. Cleaning device according to one of claims 3 to 16, characterized in that the heat exchanger (74) comprises a heat exchanger housing (90) and that the heat exchanger housing (90) defines the cooling channel (76).

18. Cleaning device according to claim 17, characterized in that the heat exchanger housing (90) defines a heat exchanger housing longitudinal axis (92) and is cylindrical or substantially cylindrical or cuboid or substantially cuboid.

19. Cleaning device according to claim 18, characterized in that the cooling channel inlet (78) and / or the cooling channel outlet (80) are arranged or formed eccentrically on the heat exchanger housing (90) with respect to the longitudinal axis (92) of the heat exchanger housing.

20. Cleaning device according to claim 18 or 19, characterized in that the cooling channel inlet (78) defines a cooling channel inlet longitudinal axis (94), that the cooling channel outlet (80) defines a cooling channel outlet longitudinal axis (96) and that the cooling channel inlet longitudinal axis (94) and / or the cooling channel outlet longitudinal axis (96) run parallel to the heat exchanger housing longitudinal axis (92).

21. Cleaning device according to claim 20, characterized in that the cooling channel inlet longitudinal axis (94) defines the cooling channel outlet longitudinal axis (96).

22. Cleaning device according to one of claims 17 to 21, characterized in that the heat exchanger housing (90) defines a heat exchanger housing length (120) and a heat exchanger housing diameter (122) and that a ratio between the heat exchanger housing length (120) and the heat exchanger housing diameter (122) is in a range of about 5:4 to about 5:1, in particular in a range of about 3:2 to about 3:1.

23. Cleaning device according to any one of claims 17 to 22, characterized in that the heat exchanger housing (90) has a heat exchanger housing wall (124) that delimits the cooling channel (76) and that the heat exchanger housing wall (124) is thermally insulated.

24. Cleaning device according to claim 23, characterized in that the heat exchanger housing wall (124) is made of a heat exchanger housing wall material which has a thermal conductivity of at most about 1 W / (m K), in particular of at most about 0.1 W / (m K).

25. Cleaning device according to any one of the preceding claims, characterized in that the cleaning device (10) comprises a CO2 connection (64) which is connected or connectable to a CO2 source (26) and that the CO2 connection (64) is fluidly connected to the CO2 connection line (22). 26.Cleaning device according to claim 25, characterized in that the expansion device (16) comprises a switching device (140) for opening and closing a fluid connection between the CO2 connection (64) and the expansion chamber inlet (20) and that the switching device (140) is arranged or formed between the cooling device (24) and the expansion chamber inlet (20).

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