Cooling device and method therefore for CO2 washing machine

Abstract

The present invention relates to a cooling unit for cooling fluid in a dry cleaning system and a method therefore. The cooling unit (12) comprises a device (1, 7, 8) containing cooled fluid such as carbon dioxide, and a tube section (11) for conveying the fluid from a first compressor stage (2) to a second compressor stage (3), arranged so that the fluid in the tube section (11) is cooled by the cooled fluid in the device (1, 7, 8).

Claims

1. An apparatus for cleaning articles comprising: a first compressor stage for a first processing of fluid, a second compressor stage for a second processing of the fluid, a first cooling unit arranged between the first and second compressor stages, the first cooling unit being configured to first cool the fluid after the first processing of the fluid, the first cooling unit comprising a storage device and a tube section within or surrounding the storage device, the storage device being configured to store the fluid after a second cooling of the fluid that takes place after the second processing of the fluid, the tube section being configured to convey the fluid from the first compressor stage to the second compressor stage such that the fluid in the tube section is cooled by the fluid in the storage device.

2. An apparatus according to claim 1, wherein the tube section is about 0.2 to about 2 meter long.

3. The apparatus according to claim 1, further comprising a second cooling unit configured to perform the second cooling of the fluid that takes place after the second processing of the fluid.

4. The apparatus according to claim 1, wherein the tube section is immersed in the fluid in the storage device.

5. The apparatus according to claim 1, further comprising a tube configured to convey the stored fluid from the storage device to one or more components of the apparatus for an operation of the apparatus for cleaning articles.

6. A method for cooling fluid being used as a solvent in a dry cleaning system, the method comprising: first compressing the fluid, first cooling the fluid after the first compressing of the fluid, second compressing the fluid after the first cooling of the fluid, second cooling the fluid after the second compressing of the fluid, storing the fluid for a period of time after the second cooling of the fluid in a storage device, wherein, the first cooling comprises, after the first compressing of the fluid and before the second compressing of the fluid, cooling the fluid by the fluid that is stored, and after passage of the period of time, conveying the stored fluid from the storage device to one or more components of the apparatus for an operation of the apparatus for cleaning articles.

7. A method for cooling fluid according to claim 6, further comprising conveying the fluid after the second compressing of the fluid to a cleaning chamber before the second cooling of the fluid.

8. A method for cooling fluid according to claim 6, further comprising conveying the fluid after the second compressing of the fluid to a distillation vessel before the second cooling of the fluid.

9. A method for cooling fluid according to claim 6, wherein the pressure of the fluid is about 50-70 bar after the second compressing of the fluid.

10. A method according to claim 6, wherein the fluid comprises carbon dioxide.

11. A cooling system comprising: a compressor unit for sequential compression of a fluid, and a cooling unit for intermediary cooling of the fluid between the sequential compressions, the cooling unit comprising a storage device of cooled fluid and a tube section within or surrounding the storage device being configured to convey fluid between the sequential compressions, the compressor unit and the cooling unit being interlinked in such a way that the intermediary cooling is made by the stored cooled fluid.

12. A cooling system according to claim 11, wherein the compressor unit is at least a two stage compressor.

13. The cooling system according to claim 11, wherein the tube section is immersed in the fluid in the storage device.

14. The cooling system according to claim 11, further comprising a tube configured to convey the stored fluid from the storage device to one or more components of the apparatus for an operation of the apparatus for cleaning articles.

Description

BRIEF DESCRIPTION OF FIGURES

(1) FIG. 1 illustrates a prior art system having a mechanical cooling unit.

(2) FIG. 2 illustrates an embodiment of the present invention wherein the cooling unit comprises a storage device for cooling the fluid.

(3) FIG. 3 illustrates an embodiment wherein flanges are arranged to the tube section in the cooling unit.

(4) FIG. 4 illustrates an embodiment wherein the tube section is folded or winded in the cooling unit.

(5) FIG. 5 illustrates an embodiment of the present invention wherein the tube section is arranged on the outside of the storage device.

(6) FIG. 6 illustrates an embodiment of the present invention wherein the tube section is arranged on the lower part on the outside of the storage device.

(7) FIG. 7 illustrates an embodiment according to the present invention wherein the cooling unit comprises a distiller for cooling the liquid.

(8) FIG. 8 illustrates an embodiment according to the present invention wherein the cooling unit comprises a cleaning chamber for cooling the liquid.

(9) FIG. 9 illustrates a method according to the present invention.

(10) FIG. 10 illustrates further method steps according to the present invention.

(11) Figures are preferably schematically drafted in order to facilitate understanding. Therefore other designs that could be drafted in the same schematic way are implicitly also disclosed in this document.

DESCRIPTION OF PREFERRED EMBODIMENTS

(12) FIG. 1 illustrates a prior art dry cleaning system comprising a storage device 1, a compressor having two compressor stages 2 and 3, a cooling unit 23 comprising a tube section 4 and an air cooled intercooler 5. The system further comprises a distiller 7 and a cleaning chamber 8 for cleaning fabrics, a refilling tube 9 and a second cooling unit 6 for cooling fluid before the fluid enters the storage device 1.

(13) FIG. 2 illustrates a first embodiment according to the present invention wherein a cooling unit 12 comprises a tube section 11 and a storage device 1. As can be seen from FIG. 1 the first compressor stage 2 is used for compressing the fluid a first time, thereafter the fluid is conveyed via the tube section 11 to the second compressor stage 3 in the compressor unit 14 for a second compression. Once the fluid has passed through both compressor stages, and the intermediate cooling unit 12, it can for example be transferred to the storage device 1 via a second cooling unit 6. It can also be conveyed via the cleaning chamber 8 to provide heat to the cleaning chamber 8 before being conveyed to the storage device 1 via the cooling unit 6. Another option is to convey the fluid after it has passed the two compressor stages via the distiller 7 and then to the storage device 1 via the second cooling unit 6.

(14) According to a cleaning process the fluid is stored in the storage device 1, and upon start of the cleaning system, after a user have entered articles to be cleaned in the cleaning chamber 8, the fluid is transferred via the tubes to the cleaning chamber 8 containing the articles to be cleaned. After a cleaning program has been executed the cleaning chamber 8 is emptied from fluid via the tubes connected to the distiller 7. In the distiller the fluid evaporates in to gas and leaves any contaminant in the distiller 7. The distiller comprises a valve so that contaminants can be removed from the distiller 7 via the valve. After the distiller, the fluid is transferred to the compressor unit 14 for compression, in the multi-stage compressor, to a working pressure of the system. After the compression the compressed fluid having an increased pressure and temperature is transferred via the tubes to the storage device 1. On the way to the storage device 1 the fluid may pass the distiller 7 so that the heat in the compressed fluid can be used to evaporate the fluid in the distiller. Before the fluid enters the storage device it usually passes a cooling unit 6.

(15) FIG. 3 illustrates a further embodiment of the present invention wherein the tube section 11 in the cooling unit 12 comprises flanges 13 in order to further improve the cooling effect in the storage device 1. By having the flanges the contact surfaces between the cooling fluid and the fluid to be cooled is increased and more efficient cooling is achieved. The arrangement of flanges on the tube section 11 can be used in all embodiments of the present invention.

(16) FIG. 4 illustrates a further embodiment of the present invention similar to the one in FIG. 3, but instead of flanges the tube section in itself is configured so that the contact surface between the cooling fluid and the fluid to be cooled is increased and thereby more efficient cooling can be achieved. For example the tube section can have a serrated form or circular windings inside the storage device 1. This design on the tube section 11 is applicable to any of the embodiments of the present invention.

(17) FIG. 5 illustrates another embodiment of the present invention wherein the tube section in the cooling unit 12 is arranged on the outside of the device 1 containing the cooling fluid. In this particular embodiment illustrated in FIG. 5 the tube section 11 is arranged on the storage device 1. However the tube section 11 can be arranged on the outside of any of the cleaning chamber 8 or the distiller 7.

(18) FIG. 6 illustrates another embodiment of the present invention wherein the tube section in the cooling unit 12 is arranged around the lower part of the storage device 1 containing the cooling fluid. By arranging the tube section 11 around the lower part of the storage device 1, a more efficient heat exchange can be achieved since the cool fluid in the storage device 1 can be in two phases, liquid and gas. The fluid in liquid phase is heavier than the fluid in gas phase and therefore collects in the bottom of the storage device 1. In this example illustrated in FIG. 6 it is the storage device 1, however this arrangement may be applicable to any of the embodiments of the present invention using the cleaning chamber 8 or the distiller 7.

(19) FIG. 7 illustrates a second embodiment of the present invention wherein the cooling unit 12 comprises a tube section 11 and a distiller 7. Since the distiller have higher efficiency compared to other devices in the system when it comes to cooling the length of the tube section 11 in the distiller 7 can be shorter compared to when the tube section 11 is arranged in for example the storage device 1.

(20) Hence the length of the tube section 11 is dependent on if the tube section 11 is arranged in the storage device 1 or in the cleaning chamber 8 or in the distiller 7. It is also dependent on if the tube section is arranged on the outside or the inside of the devices 1, 7, 8. Trial have shown that the tube section may be between 0.2 and 2 meters long depending on which device 1, 7, 8, it is associated with, and if it is arranged on the inside or the outside. For example the tube section 11 is between 0.3 and 0.7 meter long if it is arranged in the storage device 1. Preferably it is about 0.5 meter long if it is arranged in the storage device 1. However it would be enough with a tube section 11 that is between 0.1 and 0.3 meter long if the tube section 11 is arranged in the distiller 7. Preferably the tube section is about 0.2 meter long if it is arranged in the distiller 7.

(21) FIG. 8 illustrates a third embodiment according to the present invention wherein the cooling unit 12 comprises a tube section 11 and a cleaning chamber 8 containing cool fluid for cooling the fluid in the tube section 11. Even though FIG. 8 illustrates the tube section 11 being arranged in the upper part of the cleaning chamber 8 it is only for illustrative purposes. Preferably the tube section 11 is arranged in the lower parts of the cleaning chamber 8 where the cool fluid is collected.

(22) FIG. 9 illustrates a method according to the present invention. The method comprises the steps of compressing the fluid in a first stage 15, thereafter cooling the fluid in a second step 16 and in a third step 17 further compressing the fluid. The cooling step 17 comprises the step 18 of conveying the fluid via cool fluid. The fluid is conveyed in a tube section 11, as mentioned above, to be cooled by cool fluid in one of the devices 1, 7, 8. Thus the fluid is circulated in the system so that the compressed fluid will later in the process become the cool fluid that cools the fluid. Thereby the system reuses internal energy and temperature differences in the system and no external energy is necessary to add for this particular step. Furthermore the present invention also removes the need of an additional coolant liquid which saves cost. Even further the present invention is more environmental friendly due to this.

(23) FIG. 10 illustrates further steps relating to the method of the present invention. The method comprises the steps of compressing the fluid in a first stage 15, thereafter cooling 16 the fluid and in a third step 17 further compressing the fluid. The cooling step 16 comprises the step 18 of conveying the fluid via cool fluid.

(24) The method may further comprise a second cooling step 19. For example if the compressor unit 14 is a three stage compressor it would be possible to have a further cooling unit 12 (not illustrated) according to the present invention between the second compressor stage 3 and a third compressor stage (not illustrated).

(25) The method may further comprise the step of conveying the fluid to storage, such as the storage device 1. If the system does not comprise a three stage compressor the second cooling step is for example the cooling performed by the cooling unit 6 before the fluid enters the storage device 1.

(26) The fluids stored in the storage device 1 may be used for cleaning, when cleaning is about to start the method may therefore comprise the step of conveying the fluid to cleaning, for example to the cleaning chamber 8 in the figures. When the cleaning is done contaminants needs to be removed from the fluid, this process takes place in the distiller 7, Therefore the method may further comprise the step of conveying the fluid to distillation.

(27) In the above description the term comprising does not exclude other elements or steps and a or an does not exclude a plurality.

(28) Furthermore the terms include and contain does not exclude other elements or steps.