METHOD FOR OPERATING AN AIR-DRYING DEVICE FOR DRYING AIR, AIR-DRYING DEVICE FOR DRYING AIR AS WELL AS COMPRESSED AIR SYSTEM

Abstract

A method for operating an air-drying device (10) and an air-drying device (10) are provided. The air-drying device (10) has at least one adsorption device (20) with a first adsorption section (21), a second adsorption section (22), an air feed line (11), an air removal line and an analysis unit (13). The first adsorption section (21) and the second adsorption section (22) can be used alternatingly to dry air (70). The air feed line (11) feeds air (70) to be dried and is connected to an inlet opening (24) of the adsorption device (20) in a fluid-communicating manner. The air removal line (12) removes dried air (70) and is connected to an outlet opening (25) of the adsorption device (20) in a fluid-communicating manner. A compressed air system (60) for providing compressed air (70) has such an air-drying device (10).

Claims

1. A method for drying air, the method comprising the steps of: providing air-drying device comprising: at least one adsorption device with a first adsorption section and with a second adsorption section, wherein the first adsorption section and the second adsorption section can be used alternatingly for drying the air; an air feed line and an air removal line, wherein the air feed line is for feeding air to be dried and is connected to an inlet opening of the adsorption device in a fluid-communicating manner and the air removal line is for removing dried air and is connected to an outlet opening of the adsorption device in a fluid-communicating manner; and an analysis unit; feeding air to be dried for drying in the first adsorption section; determining a carbon dioxide content in the air; analyzing a result of the determination with the analysis unit; and ending the feed of air to be dried to the first adsorption section and feeding air to be dried for drying in the second adsorption section based on the step of analyzing.

2. A method in accordance with claim 1, wherein the water content in the dry air is determined after the step of determining a carbon dioxide and downstream of the first adsorption section.

3. A method in accordance with claim 1, wherein a comparison with an upper limit value or a lower limit value or with both an upper limit value and a lower limit value is carried out in the step of analyzing a result of the determination.

4. A method in accordance with claim 1, wherein short-term fluctuations of the determined content are taken into account in the step of analyzing a result of the determination by forming a mean value.

5. A method in accordance with claim 1, wherein the determination of the carbon dioxide content is carried out in the air feed line or in the air removal line or in both the air feed line and in the air removal line .

6. A method in accordance with claim 1, wherein the air to be dried is compressed before the step of feeding air to be dried for drying in the first adsorption section.

7. An air-drying device for drying air, the device comprising: at least one adsorption device comprising: a first adsorption section; a second adsorption section, wherein the first adsorption section and the second adsorption section can be used alternatingly to dry the air; an air feed line, for feeding air to be dried, connected to an inlet opening of the adsorption device in a fluid-communicating manner; an air removal line, for removing dried air, connected to an outlet opening of the adsorption device in a fluid-communicating manner; and an analysis unit, wherein air to be dried is fed for drying in the first adsorption section; and at least one carbon dioxide sensor determining a carbon dioxide content in the air, wherein the analysis unit analyzes a result of the determination and ends the feed of air to be dried to the first adsorption section and feeds air to be dried for drying in the second adsorption section based on an analysis of a measurement result of the at least one carbon dioxide sensor by the analysis unit.

8. An air-drying device in accordance with claim 7, wherein the air-drying device is configured to: feed air to be dried for drying in the first adsorption section; determine a carbon dioxide content in the air with the at least one carbon dioxide sensor; analyze a result of the determination with the analysis unit; and end the feed of air to be dried to the first adsorption section and feed air to be dried for drying in the second adsorption section based on the analysis of the result of the determination.

9. An air-drying device in accordance with claim 8, further comprising an equalizing volume arranged in the air feed line.

10. An air-drying device in accordance with claim 8, wherein the carbon dioxide sensor is arranged in the air removal line at a distance from the adsorption device.

11. An air-drying device in accordance with claim 8, further comprising a sensor device for determining a content of at least one of the following components of the air: water; oxygen; carbon monoxide; oil; sulfur dioxide; and nitrogen oxide.

12. An air-drying device in accordance with claim 8, wherein the first adsorption section or the second adsorption section or both the first adsorption section and the second adsorption section contain a plurality of desiccants arranged in layers.

13. An air-drying device in accordance with claim 12, wherein at least one of the desiccants is selected from the list comprising: molecular sieve; silica gel; and activated aluminum.

14. An air-drying device in accordance with claim 7, further comprising a further adsorption device comprising: a first adsorption section; a second adsorption section, wherein the first adsorption section and the second adsorption section can be used alternatingly to dry the air; an air feed line, for feeding air to be dried, connected to an inlet opening of the adsorption device in a fluid-communicating manner; an air removal line, for removing dried air, connected to an outlet opening of the adsorption device in a fluid-communicating manner; and an analysis unit, wherein the at least one adsorption device and the further adsorption device provide at least two adsorption devices arranged fluid mechanically in parallel or provide at least two adsorption devices arranged fluid mechanically in series or at least two adsorption devices arranged both fluid mechanically in parallel and fluid mechanically in series.

15. An air-drying device in accordance with claim 7, further comprising a carbon dioxide absorber arranged in the air removal line, the carbon dioxide absorber containing breathing lime.

16. A compressed air system for providing compressed air, the compressed air system comprising an air-drying device comprising: at least one adsorption device comprising: a first adsorption section; a second adsorption section, wherein the first adsorption section and the second adsorption section can be used alternatingly to dry the air; an air feed line, for feeding air to be dried, connected to an inlet opening of the adsorption device in a fluid-communicating manner; an air removal line, for removing dried air, connected to an outlet opening of the adsorption device in a fluid-communicating manner; and an analysis unit, wherein air to be dried is fed for drying in the first adsorption section; and at least one carbon dioxide sensor determining a carbon dioxide content in the air, wherein the analysis unit analyzes a result of the determination and ends the feed of air to be dried to the first adsorption section and feeds air to be dried for drying in the second adsorption section based on an analysis of a measurement result of the at least one carbon dioxide sensor by the analysis unit.

17. A compressed air system in accordance with claim 16, wherein the air-drying device is configured to: feed air to be dried for drying in the first adsorption section; determine a carbon dioxide content in the air with the at least one carbon dioxide sensor; analyze a result of the determination with the analysis unit; and end the feed of air to be dried to the first adsorption section and feed air to be dried for drying in the second adsorption section based on the analysis of the result of the determination.

18. A compressed air system accordance with claim 17, further comprising a sensor device for determining a content of at least one of the following components of the air: water; oxygen; carbon monoxide; oil; sulfur dioxide; and nitrogen oxide.

19. A compressed air system accordance with claim 17, wherein the first adsorption section or the second adsorption section or both the first adsorption section and the second adsorption section contain a plurality of desiccants arranged in layers and at least one of the desiccants is selected from the list comprising: molecular sieve; silica gel; and activated aluminum.

20. A compressed air system accordance with claim 17, further comprising a further adsorption device comprising: a first adsorption section; a second adsorption section, wherein the first adsorption section and the second adsorption section can be used alternatingly to dry the air; an air feed line, for feeding air to be dried, connected to an inlet opening of the adsorption device in a fluid-communicating manner; an air removal line, for removing dried air, connected to an outlet opening of the adsorption device in a fluid-communicating manner; and an analysis unit, wherein the at least one adsorption device and the further adsorption device provide at least two adsorption devices arranged fluid mechanically in parallel or provide at least two adsorption devices arranged fluid mechanically in series at least two adsorption devices arranged both fluid mechanically in parallel and fluid mechanically in series.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In the drawings:

[0048] FIG. 1 is a schematic sectional view showing a first embodiment of an air-drying device according to the present invention; and

[0049] FIG. 2 is a schematic sectional view showing a second embodiment of an air-drying device according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] Referring to the drawings, components having the same function and mode of action are always provided with the same reference numbers in FIG. 1 and FIG. 2.

[0051] FIG. 1 shows an air-drying device 10 of a compressed air system 60 according to the present invention. The air-drying device 10 has two adsorption devices 20, which are arranged in a fluid mechanically parallel manner. The quantity of dried air 70 provided can be increased in an especially simple manner here by operating both adsorption devices 20 simultaneously. If only one of the adsorption devices 20 is used to dry air 70, the respective other adsorption device 20 represents a fail-safe operation. The most uninterrupted possible operation of the air-drying device 10 according to the present invention can be ensured hereby.

[0052] The supply with air 70 to be dried is ensured by a common air feed line 11, and air 70 to be dried can be sent through a valve 14 to one of the two adsorption devices 20 or to both adsorption devices 20. The air feed line 11 is always connected for this to an inlet opening 24 of the respective adsorption device 20 in a fluid-communicating manner. The adsorption devices 20, in the shown embodiment of the air-drying device 10 according to the present invention, have an identical configuration and have each a first adsorption section 21 and a second adsorption section 22. The feeding of the air 70 to the individual adsorption sections 21, 22 is controlled and/or regulated by valves 14. Two desiccants 23 are arranged in a layered form in the adsorption sections 21, 22. The individual desiccants 23 may be especially suitable for the adsorption of a certain component of the air 70. An overall even better drying of the air 70 can be achieved thereby. The presence of two adsorption sections 21, 22, which especially have an identical configuration, makes it possible to always use one adsorption section 21, 22 for drying the air 70 and to regenerate the other adsorption section 21, 22 at the same time. The other adsorption section 22, 21 can, of course, be operated in an energy-saving inoperative mode after the conclusion of the regeneration. After the drying has been carried out in the adsorption device 20 or adsorption devices 20, air 70 is removed in a common air removal line 12, which is connected to a respective outlet opening 25 of the respective adsorption device 20 in a fluid-communicating manner. The control and/or regulation of the removal is again made possible by actuating valves 14. To equalize short-term fluctuations in the carbon dioxide content in the dried air 70, which may develop at the time of a change of the adsorption section 21, 22 being used, an equalizing volume 15 is arranged in the air removal line 12. The air 70 present in the equalizing volume 15 now acts as a buffer volume, which dilutes a short-term fluctuation in the carbon dioxide content by mixing and is thus able to equalize it. Further, a carbon dioxide absorber 50, which may contain especially breathing lime, is arranged in the air removal line 12. The carbon dioxide content in the dried air 70 provided can be reduced even more thereby.

[0053] The air-drying device 10 shown has, in addition to additional sensor devices 40, especially carbon dioxide sensors 30. The sensor devices 40 may be configured, for example, for measuring water, oxygen, carbon monoxide, oil, sulfur dioxide and/or nitrogen oxide. The carbon dioxide content in the air 70 can be determined by the carbon dioxide sensors 30. The measurement result of the carbon dioxide sensors 30 is sent to an analysis unit 13 and is analyzed in this. This has especially the advantage that saturation of at least one of the desiccants 23 of the adsorption section 21, 22 currently being used can be detected. The fact that a saturation concerning a possible adsorption of carbon dioxide often develops sooner than a saturation concerning other components of the air 70, especially a saturation concerning water.

[0054] Air 70 is fed to at least one of the adsorption sections 21, 22 during the operation of the air-drying device 10 according to the present invention. At the same time, the carbon dioxide content in the dried air 70 is determined with at least one of the carbon dioxide sensors 30, preferably with the carbon dioxide sensor 30 arranged in the air removal line 12. This determined content is analyzed in the analysis unit 13. An analysis may comprise especially a comparison with an upper limit value. If it is determined by the analysis unit 13 that this limit value is exceeded by the carbon dioxide content determined, saturation of at least one of the desiccants 23 of the adsorption section 21, 22 being used can be inferred. Based on this result of the analysis, the adsorption section 21, 22 being used is changed. A result of a determination of the content of an additional component of the air, for example, water, which is determined especially by a sensor device 40, may, of course, also be included in this analysis. By actuating the corresponding valves 14, the feed of air 70 to the adsorption section 21, 22 of the active adsorption device 20, which section is currently being used, is stopped and the feed of air 70 to the corresponding other adsorption section 22 is started. The stopping and starting may take place preferably simultaneously or at least essentially simultaneously, but also in any desired chronological order. A control or regulation of this change may be performed, for example, by the analysis unit 13. The respective other adsorption section 22, 21 is used in this manner for the drying operation and the adsorption section 21, 22 that is no longer being used can be regenerated. A repeated performance of these steps of a method according to the present invention with the now active adsorption section 221, 21 makes possible a closed-circuit type operation of an air-drying device 10 according to the present invention and as a result the essentially uninterrupted supply of dried air 70.

[0055] FIG. 2 shows another embodiment of an air-drying device 10 according to the present invention of a compressed air system 60. The individual components of the air-drying device 10 shown are essentially identical to the components of the air-drying device 10 shown in FIG. 1, so that mainly the differences between the two embodiments will be described below and reference will otherwise be made to the description given in connection with FIG. 1. Thus, the air-drying device 10 shown in FIG. 2 also has two adsorption devices 20. These adsorption devices 20 also have two adsorption sections 21, 22 each, which can alternatingly be used to dry the air 70. A change of the adsorption sections 21, 22 being used can again be carried out based on an analysis of the carbon dioxide content determined by a carbon dioxide sensor 30 in the air 70, which analysis is performed in an analysis unit 13. Further, an equalizing volume 15 is also arranged in this embodiment of an air-drying device 10 according to the present invention in the air removal line 12. A measurement result of an additional sensor device 40 is, of course also possible here during the analysis.

[0056] However, contrary to the embodiment shown in FIG. 1, the adsorption devices 20 are not arranged here in a fluid mechanically parallel manner but in series. In particular, one outlet opening 25 of one adsorption device 20 is connected to an inlet opening 24 of the other adsorption device 20 in a fluid-communicating manner via an intermediate air line 16. At least two adsorption sections 21, 22, one each of each of the two adsorption devices 20, are thus always participating in the drying of the air 70. The drying capacity of the entire air-drying device 10 can be increased thereby. This may be advantageous especially in respect to drying concerning the water content and the carbon dioxide content, because provisions may, for example, be made for the adsorption section 21, 22 being used of the adsorption device 20, through which the air flows first, absorbing above all water and for the adsorption section 21, 22 being used of the other adsorption device 20 being able to absorbed, based on this, above all carbon dioxide. An air 70, which is, on the whole, even drier, especially in terms of its water content and carbon dioxide content, can be provided hereby.

[0057] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

APPENDIX:

LIST OF REFERENCE NUMBERS

[0058] 10 Air-drying device [0059] 11 Air feed line [0060] 12 Air removal line [0061] 13 Analysis unit [0062] 14 Valve [0063] 15 Equalizing volume [0064] 16 Intermediate air line [0065] 20 Adsorption device [0066] 21 First adsorption section [0067] 22 Second adsorption section [0068] 23 Desiccant [0069] 24 Inlet opening [0070] 25 Outlet opening [0071] 30 Carbon dioxide sensor [0072] 40 Sensor device [0073] 50 Carbon dioxide absorber [0074] 60 Compressed air system [0075] 70 Air