Dry-ice cleaning in a painting installation

Abstract

A painting-installation cleaning system is provided for cleaning at least one component of a painting installation, in particular at least one component of a painting robot or of a handling robot, characterized by at least one dry-ice nozzle for producing a dry-ice jet which cleans the component.

Claims

1. A dry ice cleaning system for a component on a robot, the component being one of an atomizer and a handling tool, the robot being located in a paint booth, the system comprising: at least one stationary dry ice nozzle located in the paint booth; at least one supply device upstream from the at least one dry ice nozzle; a checking unit configured to check at least one operating parameter during a cleaning action, at least one output variable of the cleaning system depending on the at least one operating parameter and performance requirements of the cleaning action; and a valve located downstream from the at least one supply device that at least partially closes an emission of carbon dioxide to the dry ice nozzle in response to a risk of excessive escape of carbon dioxide and independent of performance requirements of the cleaning action.

2. A dry ice cleaning system as in claim 1 further comprising an agglomeration chamber upstream from the at least one dry ice nozzle, the agglomeration chamber arranged to receive fluid carbon dioxide such that a carbon dioxide mixture that comprises carbon dioxide gas and carbon dioxide particles is formable by agglomeration of carbon dioxide snow crystals; wherein the carbon dioxide mixture is mixable with a pressurized carrier gas in at least one of the agglomeration chamber and a mixing chamber to accelerate dry ice which is to be applied.

3. A dry ice cleaning system as in claim 2 wherein the liquid carbon dioxide is relaxed in the agglomeration chamber and carbon dioxide crystals are produced that are compressed and agglomerated.

4. A dry ice system as in claim 3 wherein at least one of a quality, pressure and temperature of the carbon dioxide gas which is miscible with the carbon dioxide is settable by at least one setting mechanism to influence the cleaning action before or during the cleaning action.

5. A dry ice cleaning system as in claim 4 including an upper dry ice nozzle for cleaning an electrode ring of an atomizer and a lower dry ice nozzle for cleaning an atomizer housing.

6. A dry ice cleaning system as in claim 1 wherein the at least one operating parameter includes at least one of: at least one of pressure, quantity, and temperature of carbon dioxide, at least one of pressure, quantity, and temperature of dry ice, at least one of pressure, quantity, and temperature of a carrier gas, a room temperature, a distance between the dry ice nozzle and the component to be cleaned, a position of the component to be cleaned, an orientation of the component to be cleaned, a position of the dry ice nozzle, and an orientation of the dry ice nozzle.

7. A dry ice cleaning system as in claim 1, further comprising a heating device arranged to heat a surface of the component to be cleaned in conjunction with dry ice exposure.

8. A dry ice cleaning system as in claim 7, wherein the heating device is a hot air blower directed onto the surface of the component to be cleaned.

9. A dry ice cleaning system as in claim 7, wherein the heating device operates with infrared radiation.

10. A dry ice cleaning system as in claim 7, further comprising a portion of the component to be cleaned, the portion including channels through which hot air is passed to heat the surface to be cleaned.

11. A dry ice cleaning system as in claim 7, further comprising a portion of the component to be cleaned, the portion including an electric heating device which heats the surface to be cleaned.

12. A dry ice cleaning system as in claim 1, wherein the dry-ice nozzle is a Laval nozzle.

Description

(1) The above features and embodiments according to this disclosure can be combined with each other. Other advantageous developments of this disclosure are disclosed in the sub claims or will become apparent from the description below of preferred examples of embodiment of this disclosure in conjunction with the appended figures. The figures are summarized as follows:

(2) FIG. 1 shows a top view of part of a painting installation in the form of a painting booth, and a cleaning system according to an embodiment,

(3) FIG. 2 shows a side view of a part of a cleaning system according to an embodiment,

(4) FIG. 3 shows a view of a dry-ice nozzle of a cleaning system according to an embodiment,

(5) FIG. 4 shows a schematic representation of the indirect jet exposure and cleaning of a particular part of the coating mechanism, and

(6) FIG. 5 shows a possible division of the surface of a component to be cleaned for sequential jet exposure and cleaning.

(7) The embodiments shown in the figures partially correspond, with similar or identical parts being provided with the same reference signs, and for their explanation reference also being made to the description of one or more other embodiments, in order to avoid repetition.

(8) FIG. 1 shows a top view of a part of a painting installation in the form of a painting booth 100, for example, for vehicle bodies or their attachment parts and other parts, and a cleaning system 1 according to an embodiment. In FIG. 1, for clarity only two cleaning systems 1 are provided with reference signs, although a total of six cleaning systems can be seen in FIG. 1. The cleaning system 1 comprises at least one dry-ice nozzle 2 for applying dry ice to a component B to be cleaned. The dry ice is emitted by the dry-ice nozzle 2 in the form of a dry-ice jet, e.g., a jet of carbon dioxide snow.

(9) The component B to be cleaned is borne and guided by a robot RB which is configured such that the robot RB positions the component B to be cleaned in front of the dry-ice nozzle 2 and during the cleaning operation moves, e.g., rotationally, transversely, or translationally moves, the component B relative to the dry-ice nozzle 2. The dry-ice nozzle 2 is arranged in the painting booth 100 in stationary manner. In the example illustrated, the robots RB may typically be painting robots and/or handling robots, and the component B may be the atomiser or handling tool thereof.

(10) The cleaning system 1 comprises a supply device V for supplying the dry-ice nozzle 2 with the dry ice or generally carbon dioxide for producing the dry ice.

(11) For example, the cleaning system 1 comprises a main supply line RL for connecting the supply device V to a plurality of dry-ice nozzles 2 via respectively one stub line SL which branches off from the ring line RL to the respective dry-ice nozzle 2.

(12) The cleaning system 1 furthermore comprises a checking unit KE (e.g. camera sensor, temperature sensor, etc.), which is shown only diagrammatically in FIG. 1, for checking at least one parameter which allows a conclusion to be drawn about the hardware elements associated with the cleaning system 1, the elements necessary for producing the dry ice (e.g., carbon dioxide and carrier gas), the cleaning operation, e.g., the cleaning result, etc.

(13) The checking unit KE is shown separated from the dry-ice nozzle 2 and the robot RB in FIG. 1. In the context of this disclosure, it is however possible for the checking unit KE to be formed in or on the robot RB, on or in the dry-ice nozzle 2 and/or at another suitable position.

(14) It is advantageous that, dependent on the at least one parameter by means of at least one setting means ER (see FIG. 2), at least one output variable of the cleaning system 1 can be set, e.g., regulated and/or controlled, in order to be able to set the hardware elements associated with the cleaning system 1, the elements necessary for producing the dry ice (e.g. carbon dioxide and carrier gas), the cleaning operation, e.g., the cleaning result, etc., according to requirements.

(15) The cleaning system 1 is designed to be explosion-protected. The cleaning system 1 furthermore comprises a valve SV which for safety automatically closes or at least reduces an emission of carbon dioxide if a potential, e.g., imminent, excessive escape of carbon dioxide or one which has already taken place is ascertained by a detection mechanism (e.g. a sensor). By way of example, in FIG. 1 the valve SV is shown at the exit from the supply device V, but can be positioned at a large number of other suitable locations.

(16) FIG. 2 shows a partially schematic side view of a part of a cleaning system 1 according to another embodiment.

(17) FIG. 2 shows two dry-ice nozzles 2 which are respectively carried and guided movably by a schematically-indicated robot RT. The dry-ice nozzles 2 emit dry ice 3 in the form of a dry-ice jet.

(18) The robots RT are configured such that they position the dry-ice nozzles 2 in front of the component B to be cleaned, which here is depicted as a rotary atomiser, and during the cleaning operation move them relative to the component to be cleaned. The robot RT can rotate the dry-ice nozzles 2, e.g., at least partially about the component B to be cleaned, so that the entire outer periphery of the component B to be cleaned can be cleaned by only one dry-ice nozzle 2.

(19) In FIG. 2, the upper dry-ice nozzle 2 cleans an electrode ring of an atomiser, and the lower dry-ice nozzle 2 cleans an atomiser housing and/or the bell cup of the atomiser. It is however also possible for, e.g., only a single dry-ice nozzle 2 to be provided which is guided by a robot RT which is configured such that the robot RT positions the dry-ice nozzle 2 in front of the component B to be cleaned and during the cleaning operation moves the component B, e.g., upwards/downwards to different portions of the component B to be cleaned (e.g., from the electrode ring or electrode fingers to the atomiser housing, and following this to the bell cup and optionally the hand axis of the robot RB). This means that different portions of the component B to be cleaned can be cleaned with a reduced number of dry-ice nozzles.

(20) The dry-ice nozzles 2 may be mounted fixedly or exchangeably on the robots RT. In the latter variant, it is possible for the dry-ice nozzles 2 to be put down automatically after a cleaning operation and to be picked up before a cleaning operation. The robots RT carrying the dry-ice nozzles 2 can be configured accordingly for this purpose.

(21) The dry-ice nozzles 2 comprise a protective element S shown schematically in FIG. 2, which is designed as a protective sheet or protective housing, in order to prevent dirt particles detached during cleaning or dry ice 3 from striking a component to be painted.

(22) The cleaning system 1 shown in FIG. 2 is designed such that the component B to be cleaned can be cleaned in a substantially exposed manner by the dry ice 3 and thus conventional cleaning receptacles, into which the component to be cleaned has to be introduced, can be dispensed with. The cleaning system 1 comprises an air-stream generation mechanism LE which generates a downwards air stream to guide cleaned-off dirt or emitted dry ice 3 downwards, e.g, via a painting booth floor in the form of a grating and out of the painting booth 100. The cleaning system 1 may also comprise a cleaning receptacle, into which the component B to be cleaned is introduced, e.g., by means of the robot RB, in order to clean it by means of at least one dry-ice nozzle 2.

(23) FIG. 2 furthermore shows a schematically illustrated setting means ER, which by way of example is in an operative connection with the robots RT carrying the dry-ice nozzles 2, the dry-ice nozzles 2 and the robot RB carrying the component B to be cleaned, in order to set them according to requirements. The setting mechanism ER can however also be used to set, e.g., the quantity, pressure and temperature of the carrier gas which is miscible with the carbon dioxide and of the carbon dioxide for producing the dry ice 3. It is possible to provide a setting mechanism ER optionally consisting of a plurality of sub-units as in FIG. 1 to set a plurality of elements. It is, however, also possible to provide a plurality of setting mechanisms, which are respectively associated, e.g., with only a single element.

(24) Although the cleaning angle of the upper dry-ice nozzle 2 which is shown in FIG. 2 is substantially horizontal and the cleaning angle of the lower dry-ice nozzle 2 is directed upwards, in the context of this disclosure it is possible for the dry-ice nozzles 2 to be directed downwards during a cleaning operation, so that detached dirt particles can be carried away downwards more easily or more quickly.

(25) It should be mentioned that in the context of this disclosure it is also possible for both a dry-ice nozzle 2 to be carried and guided by a robot RT and for the component B to be cleaned to be carried and guided by a robot RB, and for them to be moved relative to each other during the cleaning process. The movements in such case can be selected at will. For example, the component B to be cleaned can be, e.g., rotated and moved translationally relative to the dry-ice nozzle 2. Likewise, it is possible for the dry-ice nozzle 2, e.g., at least in portions, to be rotated about the component B to be cleaned, and simultaneously or in succession for the dry-ice nozzle 2 to be moved along the component to be cleaned (e.g., from the bell cup to the electrode ring). The movements of the dry-ice nozzle 2 and of the component B to be cleaned may take place simultaneously or in succession.

(26) It should furthermore be mentioned that the dry-ice nozzles 2 shown in FIG. 2, similarly to what is shown in FIG. 1, can also be arranged without the robots RT, e.g., in stationary manner. In this case, the component B to be cleaned may again be positioned in front of the dry-ice nozzles 2 by the robot RB carrying and guiding it, and be moved, e.g., rotated (arrow P1) and/or moved transversely/translationally (arrow P2) relative to the dry-ice nozzles 2.

(27) FIG. 3 shows a view of a dry-ice nozzle 2 of a cleaning system 1 according to an embodiment.

(28) The dry-ice nozzle 2 comprises an agglomeration chamber AK to which fluid carbon dioxide (CO2) can be supplied and in which a two-phase carbon dioxide mixture which comprises carbon dioxide gas and carbon dioxide particles can be formed by agglomeration of carbon dioxide snow crystals. The liquid carbon dioxide supplied to the agglomeration chamber AK is relaxed in the agglomeration chamber AK, and carbon dioxide crystals are produced which are compressed and agglomerated.

(29) The carbon dioxide mixture is mixed with a pressurised carrier gas TG (e.g., compressed air) in the agglomeration chamber AK, preferably in order to accelerate it. In one embodiment of the invention, not shown, it is possible for the agglomeration chamber AK to be connected, e.g., via a metering opening, to a mixing device in the form of a mixing chamber, and for the carbon dioxide mixture to be mixed with the pressurised carrier gas TG in the mixing chamber. In the embodiment shown in FIG. 3, the agglomeration chamber AK so to speak takes on the function of a mixing chamber, so that the agglomeration chamber and the mixing chamber virtually represent one and the same chamber.

(30) It can be seen from FIG. 3 that the dry ice 3 is at least partially carbon dioxide, e.g., a two-phase carbon dioxide mixture which comprises carbon dioxide gas and carbon dioxide particles. The two-phase carbon dioxide mixture is mixed with the pressurised carrier gas TG in the agglomeration and/or mixing chamber before the dry ice 3 is applied from the dry-ice nozzle 2. The dry ice emitted from the dry-ice nozzle 3 is thus preferably a two-phase carbon dioxide mixture which is provided with a pressurised carrier gas TG, and is, e.g., emitted from the dry-ice nozzle 2 in the form of a carbon dioxide snow jet.

(31) The dry-ice nozzle 2 is adjustable in its nozzle contour (e.g., the jet divergence angle can be changed, which is indicated by the arrow P3). Alternatively or additionally, the dry-ice nozzle 2 may comprise an adjustment function to be able to change its orientation, e.g., the cleaning angle. These features make possible adaptation to different outer contours of the component B to be cleaned or generally make the cleaning operation able to be set according to requirements.

(32) The cleaning system 1 may furthermore have a carrier-gas heater TE indicated schematically in FIG. 3 for heating the carrier gas TG.

(33) The cleaning system 1 in the context of this disclosure may comprise a plurality of dry-ice nozzles 2, which are fixedly arranged or can be arranged such that they can preferably cover the entire outer periphery of the component B to be cleaned and/or that they can correspond to the outer contour of the component B to be cleaned.

(34) In an embodiment, not shown, one robot carries both an atomiser and a dry-ice nozzle, which is attached to and arranged on the robot such that the function of the atomiser is not impaired by the dry-ice nozzle. For this purpose, the dry-ice nozzle may be shielded from the atomiser, e.g., by a covering.

(35) FIG. 4 shows the possibility of exposure and cleaning the object to be cleaned optionally partially indirectly with dry ice, by the example of an application component 40 illustrated diagrammatically as a rotary atomiser. The upper part of this component 40 in FIG. 4 can be exposed to the jet directly (not shown), whereas the lower region 41 in the vicinity of the bell cup 44 is indirectly exposed to the jet and cleaned. In this example, the dry-ice nozzle 42 is therefore not directed directly onto the surface of the region 41, which here is cylindrical or conical, but is arranged such that the dry-ice jet 43 brushes laterally or tangentially past the surface to be cleaned. This spraying-past has the advantage that, for example, the surface to be cleaned is not deformed or damaged by particles impinging thereon. The spraying-past of the cold carbon dioxide carrier gas mixture in this case effects cooling of the contaminated surface and removal of the soiling by the air stream. Of course, other surfaces can also be indirectly exposed to the jet and cleaned, while yet other component regions can be cleaned by direct application of dry ice to the respective component.

(36) FIG. 5 shows a possible division of the surface of a coating mechanism 50, which is divided into sections for the sequential cleaning. In the example illustrated, the coating mechanism 50 is part of the rotary atomiser of a painting robot (not shown, but cf. robot RB and component B in FIG. 2) with adjacent regions or sections 51, 52, 53 and 54. Each section can be approached separately with a painting robot and then cleaned by the painting robot rotating the coating means 50 in the programmed position 360 about the dry-ice nozzle. After this cleaning, the painting robot can carry on with its normal painting activity until the next section is due to be cleaned. The control of the various cycles and dependencies is dictated by the robot control, or they can also be determined and implemented by visual measurement methods for example dependent on the degree of soiling.

(37) The invention is not limited to the preferred embodiments described above. Rather, a large number of variants and modifications, which likewise make use of the inventive concept and therefore fall within the scope of protection, is possible. Protection is claimed for the subject-matter and the features of the individual dependent claims independently of the subject-matter and the features of the claims referred to.