Patent Application
20250041914
The present invention relates to cleaning appliances for blasting surfaces to be treated with a mixed stream of a pressurized gas and CO2 pellets generally, and more specifically to a cleaning appliance for blasting surfaces to be treated with a mixed stream of a pressurized gas and CO2 pellets, comprising an apparatus for producing CO2 pellets from liquid or gaseous CO2, wherein the apparatus comprises a compressing device for compressing CO2 snow to form the CO2 pellets, wherein the compressing device comprises an expansion device for creating 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 appliance comprises a CO2 connection line that is fluidically connected to the expansion chamber inlet for supplying the liquid or gaseous CO2 to the expansion device.
A cleaning appliance of the kind described at the outset is known, e.g., from WO 2015/079022 A1. With this cleaning appliance, it is possible to produce CO2 pellets, i.e. so-called dry ice pellets, from liquid CO2.
A problem with known cleaning appliances of that kind is, in particular, the limited yield of CO2 pellets producible from a predetermined amount of liquid CO2.
In a first aspect of the invention a cleaning appliance for blasting surfaces to be treated with a mixed stream of a pressurized gas and CO2 pellets, comprises an apparatus for producing CO2 pellets from liquid or gaseous CO2. The apparatus comprises a compressing device for compressing CO2 snow to form the CO2 pellets. The compressing device comprises an expansion device for creating CO2 snow by expanding liquid or pressurized CO2. The expansion device comprises an expansion chamber with an expansion chamber inlet. The cleaning appliance comprises a CO2 connection line that is fluidically connected to the expansion chamber inlet for supplying the liquid or gaseous CO2 to the expansion device. The cleaning appliance comprises a cooling device for cooling the CO2 connection line.
The foregoing summary and the following description may be better understood in conjunction with the drawing figures, of which:
Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.
The present invention relates to a cleaning appliance for blasting surfaces to be treated with a mixed stream of a pressurized gas and CO2 pellets, comprising an apparatus for producing CO2 pellets from liquid or gaseous CO2, wherein the apparatus comprises a compressing device for compressing CO2 snow to form the CO2 pellets, wherein the compressing device comprises an expansion device for creating 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 appliance comprises a CO2 connection line that is fluidically connected to the expansion chamber inlet for supplying the liquid or gaseous CO2 to the expansion device, wherein the cleaning appliance comprises a cooling device for cooling the CO2 connection line.
The further development proposed in accordance with the invention makes it possible, in particular, to improve the efficiency of the cleaning appliance, i.e. in particular to increase the yield of CO2 pellets from a predetermined amount of liquid CO2. By means of the cooling device, the starting product of the cleaning appliance, i.e. pressurized gaseous or liquid CO2, can be cooled. The colder the gaseous or liquid CO2 is, the more efficiently it can be used in the subsequent process. Thus, more CO2 snow can be produced, the colder the gaseous or liquid CO2 used for this is. The cooling device may here be, in particular, an active cooling device, which cools the CO2 connection line. For example, the cooling device can be powered by electricity.
To increase the efficiency of the cleaning appliance, provision may further be made that the cooling device is configured in the form of a passive cooling device. This has the advantage, in particular, that no additional energy has to be used to cool the CO2 connection line. For example, the passive cooling device may be configured in the form of a counterflow cooling device. Thus, for example, a cool exhaust gas of the cleaning appliance, for example cool CO2, can be used to cool the CO2 connection line. In the counterflow cooling device, however, direct contact between the medium to be cooled, i.e. the liquid or gaseous CO2 on the one hand, and the cooling medium on the other hand is prevented. Alternatively, any other sufficiently cool gas or liquid flow can be used as a cooling medium. The cooling device makes it possible, in particular, to pre-cool liquid CO2 from bottles, which are not pre-conditioned, in order to thus create as much CO2 snow as possible when expanding the liquid or gaseous CO2.
The cleaning appliance can be formed in a simple manner if the cooling device comprises a heat exchanger and if the CO2 connection line extends through the heat exchanger. This configuration makes it possible, in particular, to directly cool the CO2 connection line, namely in the region in which 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 that has a correspondingly low temperature.
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 connection line extends through the cooling channel. In particular, a connection line portion of the CO2 connection line may extend through the cooling channel. Thus, in particular, it is not absolutely necessary that the entire CO2 connection line is cooled, but rather it is sufficient if at least a connection line portion of the CO2 connection line is cooled.
It is favorable if the heat exchanger has an inlet side and an outlet side and 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 the outlet side are spatially separated from one another, the cooling channel inlet and the cooling channel outlet can thus also be separated from one another in a simple manner. An optimal flow of a cooling fluid through the heat exchange can thus be achieved.
Preferably, the connection line portion 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 connection line by the counterflow method by means of a cooling fluid flowing through the cooling channel.
It is favorable if the connection line portion has a connection line portion length, if the cooling device has a cooling device length, which corresponds to a distance between the inlet side and the outlet side, and if a ratio between the connection line portion length and the cooling device length is in a range of about 5:1 to about 25:1. Such a configuration makes it possible, in particular, to select or predetermine a largest possible surface area of the heat exchanger that is optimized for heat exchange. The cooling device can still be formed compactly, however, in order to achieve a smallest possible size thereof, such that the cleaning appliance as a whole can maintain a moderate, manageable size.
For a simple handling of the cleaning appliance, it is advantageous if the cooling channel inlet and/or the cooling channel outlet comprise a hose connection piece for connecting to a hose in a fluid-tight manner. In particular, such a configuration makes it possible in a simple manner to conduct a cooling fluid through a hose to the cooling device and away therefrom after flowing through the cooling device.
It is favorable if the compressing device comprises a CO2 exhaust gas outlet and if the CO2 exhaust gas outlet is fluidically connected to the cooling channel inlet. This configuration makes it possible, in particular, to use the gaseous CO2 exiting the pre-compression device, which has a significantly lower temperature than the ambient temperature of the cleaning appliance, as a cooling medium for cooling the CO2 connection line, in particular the connection line portion thereof. Sublimated, i.e. gaseous, CO2 that is created in the pre-compression device is then not only emitted to the environment of the cleaning appliance, but instead is first used to pre-cool the CO2 connection line. The cooling device can thus be used, in particular, as a passive cooling device. No additional energy requirement is necessary to cool the CO2 connection line. Rather, a waste product in the use of the cleaning appliance, namely cooled gaseous CO2, is used as cooling fluid.
It is advantageous if the cleaning appliance comprises a CO2 cleaning appliance exhaust gas outlet and if the cooling channel outlet is fluidically connected to the CO2 cleaning appliance exhaust gas outlet. This configuration makes it possible, in particular, to discharge the gaseous CO2 from or out of the cleaning appliance in a defined manner, for example to an environment thereof, after flowing through the cooling device. Optionally, the CO2 cleaning appliance exhaust gas outlet may also be connected to a hose, for example in order to discharge the gaseous CO2 created during the production process of CO2 pellets from a cleaning space in which a surface to be treated is acted upon with a mixture of a pressurized gas and CO2 pellets. A proportion of CO2 in the ambient air of the cleaning appliance can thus be controlled in a defined manner.
Preferably, the cooling device comprises at least one heat conducting element, which is in thermal connection with the connection line portion. The at least one heat conducting element serves the purpose, in particular, of increasing a surface area of the connection line portion in order to thus achieve an improved heat exchange in the region of the cooling device.
The cooling device can be configured in a simple manner if the at least one heat conducting element is configured in the form of a heat conducting rib projecting from the connecting line portion and/or in the form of a woven fabric body, knitted fabric body, or wool body. Cooling medium, for example cold gaseous CO2, can flow around heat conducting ribs or the described woven fabric body, knitted fabric body, or wool body, and cool them in this way. They are suited to remove heat from the connection line portion, so that the cooling fluid stream flowing through the cooling device is able to absorb this heat.
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 about 30 W/(m K). In particular, the thermal conductivity may be at least about 100 W/(m K). In particular, thermal conducting elements that are made of a metallic material are suitable for this purpose. Zinc, for example, has a thermal conductivity of about 110 W/(m K), aluminum about 230 W/(m K). Copper has a thermal conductivity in the range of about 240 to 380 W/(m K).
The cooling device can be configured in a simple and cost-effective manner if the at least one heat conducting element is made of a metallic material. Compared to plastic materials, metallic material, in particular pure metals or metal alloys such as, e.g., copper alloys or aluminum alloys, have a significantly higher thermal conductivity.
In order to increase a surface area of the CO2 connection line, it is advantageous if the connection line portion is of helical configuration. In particular, it may be configured in the form of a helical coil. For this purpose, the connection line portion may be configured in form of a pipe that is helically wound.
In order to achieve a best possible heat transfer, it is favorable if the connection line portion is made of a metallic material. In particular when the connection line portion is in thermal contact with at least one heat conducting element, a cooling fluid flowing past the connection line portion can thus absorb heat from the connection line portion and can thus cool it.
A particularly compact structure of the cleaning appliance can be achieved, in particular, in that the heat exchanger comprises a heat exchanger housing and in that the heat exchanger housing defines the cooling channel. The flow of a cooling medium can thus be achieved in a simple manner, in particular by being conducted through the heat exchanger housing.
It is advantageous if the heat exchanger housing defines a heat exchanger housing longitudinal axis and is of cylindrical or substantially cylindrical or cuboidal or substantially cuboidal configuration. In this way, the cooling device can be configured in particular in a compact manner and a cooling of the CO2 connection line can be optimized.
For a good cooling result, it is favorable if the cooling channel inlet and/or the cooling channel outlet is arranged or formed excentrically on the heat exchanger housing relative to the heat exchanger housing longitudinal axis. Thus, for example, the cooling channel inlet may be arranged on the inlet side of the heat exchanger excentrically or coaxially with the heat exchanger housing longitudinal axis. The CO2 connection line on the inlet side may be conducted out of the heat exchanger housing coaxially with the heat exchanger housing longitudinal axis in the case of an excentrically arranged cooling channel inlet, or may also be conducted excentrically out of the heat exchanger housing relative to said heat exchanger housing longitudinal axis. In a corresponding manner, the cooling channel outlet may be arranged on the outlet side excentrically or coaxially with the heat exchanger housing longitudinal axis. Furthermore, in the case of an excentrically arranged cooling channel outlet, the CO2 connection line may be conducted on the outlet side into the heat exchanger housing coaxially with the heat exchanger housing longitudinal axis or also excentrically relative to said heat exchanger housing longitudinal axis. In particular, an optimal cooling of the connection line portion of the CO2 connection line in the heat exchanger housing according to the counterflow principle can be achieved in this way.
In accordance with a further preferred embodiment, provision may be made 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 extend in parallel to the heat exchanger housing longitudinal axis. This configuration makes it possible, in particular, to conduct the cooling fluid into the heat exchanger housing in a defined manner. In particular, a flow of the cooling fluid can thus be optimized so that a heat exchange preferably takes place in the heat exchanger housing and not before, i.e. outside of said heat exchanger housing.
Preferably, the cooling channel inlet longitudinal axis defines the cooling channel outlet longitudinal axis. The cooling channel inlet and the cooling channel outlet can thus be arranged or formed coaxially with one another on the heat exchanger. Thus, in particular, an optimized flow of the cooling fluid through the heat exchanger can be achieved.
It is advantageous if the heat exchanger housing defines a heat exchanger housing length and a heat exchanger housing diameter, and if a ratio between the heat exchanger housing length and the heat exchanger housing diameter is in a range of about 5:4 to about 5:1. In particular, the ratio may be in a range of about 3:2 to about 3:1. A heat exchanger of that kind is particularly compact in its design and can be retrofitted in a simple manner, for example to cleaning appliances that are already on the market.
It is favorable if the heat exchanger housing has a heat exchanger housing wall delimiting the cooling channel and if the heat exchanger housing wall is thermally insulated. It can thus be prevented, in particular, that the cooling medium excessively cools an environment of the heat exchanger. In other words, a cooling effect of the cooling fluid for the CO2 connection line can thus be improved.
For a good thermal insulation of the cooling device, it is favorable if the heat exchanger housing wall is made of a heat exchanger housing wall material, which has a thermal conductivity of at most about 1 W/(m K). In particular, the thermal conductivity may be at most about 0.1 W/(m K). For example, the heat exchanger housing wall may be made of a plastic material, for example on a polyethylene or polystyrene basis. Polyurethane could also be considered as a heat exchanger housing wall material. The heat exchanger housing wall may optionally also comprise an insulating layer made of an insulation material suitable for this purpose, which preferably has a thermal conductivity that does not exceed the stated limit values. Possible suitable insulating materials are, in particular, mineral wool, sheep's wool, cellulose, flax, or wood fibers.
In accordance with a further preferred embodiment, provision may be made that the cleaning appliance comprises a CO2 connection, which is connected or connectable to a CO2 source, and that the CO2 connection is fluidically connected to the CO2 connection line. Such a cleaning appliance can be connected, for example, to a CO2 bottle that contains liquid CO2. The CO2 can then be supplied via the CO2 connection line to the expansion device.
It is advantageous if the expansion device comprises a switching device for opening and closing a fluidic 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, such that liquid or gaseous CO2 is only able to flow through the CO2 connection line when the fluidic connection between the CO2 connection and the expansion chamber inlet is open. The formation of CO2 snow can thus be controlled in a simple manner with the switching device.
Schematically depicted in
The apparatus 12 comprises a compressing device 14 for compressing CO2 snow to form the CO2 pellets.
The compressing device 14 comprises an expansion device 16 for creating CO2 snow by expanding liquid or pressurized CO2. The expansion device 16 comprises an expansion chamber 18 with an expansion chamber inlet 20. Furthermore, the cleaning appliance 10 comprises a CO2 connection line 22 that is fluidically connected to the expansion chamber inlet 20 for supplying the liquid or gaseous CO2 to the expansion device 16.
For pre-cooling the liquid or gaseous CO2, the cleaning appliance 10 comprises 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 may be, in particular, a CO2 bottle 28 with liquid CO2 or a CO2 pressurized gas source.
In the embodiment of the cleaning appliance 10 depicted in
Schematically depicted in
The apparatus 12 comprises a compressing device 14 for compressing CO2 snow to form the CO2 pellets.
The compressing device 14 comprises an expansion device 16 for creating CO2 snow by expanding liquid or pressurized CO2. The expansion device 16 comprises an expansion chamber 18 in the form of a pipe 30 bent by 90°.
The expansion chamber 18 comprises an expansion chamber inlet 20, on which an expansion nozzle not depicted in the Figures is arranged, by means of which liquid or pressurized gaseous CO2 is able to be conducted into the expansion chamber 18. The expansion chamber 18 forms a portion of a pre-compression device 32 in which CO2 snow is pre-compressed and then supplied to the main compressing device 36 configured in the form of a gear compressor 34.
A pellet delivery device 38 is arranged downstream of the main compressing device 36.
The pellet delivery device 38 comprises a pressurized gas inlet 40, which is fluidically connected to a pressurized gas connection 44 by way of a connection line 42. Arranged on the connection line 42 is a valve 46 in order to selectively open or close the connection line 42 to enable or interrupt a pressurized gas stream.
The pellet delivery device 38 further comprises a mixed stream outlet 48, which is fluidically connected to a mixed stream connection 52 by way of a connection line 50. The mixed stream connection 52 can be connected by way of a hose to a blasting nozzle, which can be guided by a user for cleaning or blasting the surfaces to be treated with the mixed stream. For the sake of clarity, both the hose and the blasting nozzle are not depicted in the Figures.
The compressing device 14 comprises a CO2 exhaust gas outlet 54, out of which gaseous CO2 exits the compressing device 14, said gaseous CO2 being created through sublimation during the production of CO2 pellets.
The cleaning appliance 10 further comprises a CO2 cleaning appliance exhaust gas outlet 56, which is fluidically connected to the CO2 exhaust gas outlet 54, namely by way of a CO2 exhaust gas line 58.
The cleaning appliance 10 further comprises a movable frame 60 on which all components of the cleaning appliance 10 are arranged. The cleaning appliance 10 can thus be moved by a user in a simple and comfortable manner.
Formed on the frame 60 is a platform 62 on which a CO2 bottle 28 is positionable as schematically depicted in
The cleaning appliance 10 comprises a CO2 connection 64, which is conducted out of a housing 66 of the cleaning appliance 10. The CO2 connection 64 can be connected to a connection 70 of the CO2 bottle 28 by way of a connecting line 68. The CO2 connection 64 is fluidically connected to the CO2 connection line 22 in this way.
In the embodiment of
The cooling device 24 comprises a heat exchanger 74 through which the CO2 connection line 22 extends.
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 portion 82 of the CO2 connection line 22, extends through the cooling channel 76.
The heat exchanger 74 defines an inlet side 84 and an outlet side 86, namely 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.
The connection line portion 82 extends between the outlet side 86 and the inlet side 84 through the cooling channel 76.
The connection line portion 82 is of helical configuration, as is schematically depicted, in particular, in
The connection line portion 82 is of pipe-shaped configuration and is made of a metallic material.
The heat exchanger 74 comprises a heat exchanger housing 90, which delimits and thus defines the cooling channel 76. In the embodiment depicted in
As schematically depicted in
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 embodiment depicted in the Figures, the cooling channel inlet longitudinal axis 94 and the cooling channel outlet longitudinal axis 96 extend in parallel to the heat exchanger housing longitudinal axis 92, but laterally offset therefrom. In other words, the heat exchanger housing longitudinal axis 92 does not coincide with the two other axes.
In the embodiment depicted in
The heat exchanger housing 90 comprises a pipe-shaped housing wall 98 extending 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.
The cooling channel inlet 78 is configured in the form of a bore 106 of the end wall 100 provided with an internal thread 104. The cooling channel outlet 80 is configured in the form of a bore 110 of the end wall 102 provided with an internal thread 108.
The cooling channel inlet 78 comprises a hose connection piece 112, which comprises an externally threaded portion 114 corresponding to the internal thread 104. The hose connection piece 112 is screwed into the bore 106. An end portion of the hose connection piece 112 pointing away from the end wall 100 is connected to the hose-shaped CO2 exhaust gas line 58, which is in direct fluidic connection with the CO2 exhaust gas outlet.
A further hose connection piece 116 is screwed to the bore 110 with an externally threaded portion 118 corresponding to the internal thread 108. An end portion of the hose connection piece 116 pointing away from the end wall 102 is connected to a further portion of the CO2 exhaust gas line 58 that is in direct fluidic connection with the CO2 cleaning appliance exhaust gas outlet 56.
The heat exchanger housing 90 defines a heat exchanger housing length 120 and a heat exchanger housing diameter 122. In the embodiment depicted in
The heat exchanger housing wall 124 is optionally thermally insulated. Optionally, it is made of a heat exchanger housing wall material, which has a thermal conductivity of at most about 1 W/(m K). In preferred embodiments, the thermal conductivity of the heat exchanger housing wall material is at most about 0.1 W/(m K).
In the embodiment depicted in the Figures, the connection line portion 82 has a connection line portion length 126. The connection line portion length 126 is defined by a length of the connection line portion 82 between the end walls 100 and 102, namely by a center line 128 of the connection line portion 82.
The cooling device 24 defines a cooling device length 130, which corresponds to a distance 132 between the inlet side 84 and the outlet side 86.
The helical configuration of the connection line portion 82 results in a ratio between the connection line portion length 126 and the cooling device length 130 in a range of about 5:1 to about 25:1. The surface area of the connection line portion 82 is increased in this way compared to a configuration in which the connection line portion would extend in parallel to the heat exchanger housing longitudinal axis 92 through the cooling channel 76.
For improving a heat exchange between the cooling channel 76 and the gaseous CO2 flowing therethrough on the one hand and the connection line portion 82 and the liquid CO2 flowing therethrough on the other hand, the cooling device 24 optionally comprises one or more heat conducting elements 134, which is/are in thermal connection with the connection line portion 82. As an example, a heat conducting element 134 in the form of a woven fabric body, knitted fabric body, or wool body 136 is depicted in
Alternatively and purely schematically, optional heat conducting elements 134 in the form of heat conducting ribs 138 are drawn in
The heat conducting elements 134 are optionally made of a metallic material.
In one embodiment, the heat conducting elements 134 are made of a heat conducting body material, which has a thermal conductivity of at least about 30 W/(m K). Preferably, the thermal conductivity of the heat conducting body material is at least about 100 W/(m K).
In order to be able 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 fluidic 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 depicted in
By means of the cooling device 24, an efficiency in the production of CO2 pellets with the compressing device 14 can be significantly increased, namely by 25% compared to a cleaning appliance 10 that has no heat exchanger 74. In other words, this means that with the same contents of the CO2 bottle 28, 25% more CO2 pellets can be produced with the cleaning appliance 10 according to the embodiment of
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2022 109 526.6 | Apr 2022 | DE | national |
This application is a continuation of international application number PCT/EP2023/059992, filed on Apr. 18, 2023, and claims the benefit of German application number 10 2022 109 526.6, filed on Apr. 20, 2022, which are incorporated herein by reference in their entirety and for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2023/059992 | Apr 2023 | WO |
| Child | 18918999 | US |
