PROCESS AND DEVICE FOR PROVIDING VAPOR

Abstract

The present invention is directed to a method and an apparatus for providing vapor for a discontinuous process.

Claims

1. A method for providing vapor for a discontinuous process, the method comprising: evaporating a liquid in a direct evaporator for generating a vapor; transporting the vapor from the direct evaporator to a process region via a storage volume, wherein the temperature of the storage device is closed loop controllable; wherein the fluid connection between the storage volume and the process region is interrupted if no vapor is required in the process region, and wherein vapor continues to be generated and transported into the storage volume at least temporarily during the interruption so that the pressure within the storage volume increases during the interruption.

2. The method according to claim 1, wherein the temperature of the storage volume is closed loop controlled during the interruption, wherein the storage volume is heated during the interruption.

3. The method according to claim 1, wherein the temperature of the storage volume is at least so high that during the interruption no condensation of the vapor occurs within the storage volume.

4. The method according to claim 1, wherein vapor continues to be generated and transported into the storage volume continuously during the complete interruption period.

5. The method according to claim 1, wherein the fluid connection between the storage volume and the process region is restored as soon as vapor is required in the process region.

6. The method according to claim 1, wherein the interruption and/or the restoration of the fluid connection between the storage volume and the process region takes place by means of an automatically closed loop controlled valve.

7. The method according to claim 1, wherein the discontinuous process is a clocked process so that vapor is alternatingly required or not required within the process region, wherein the interruption and restoration of the fluid connection between the storage volume and the process region is clocked as well and wherein vapor continues to be generated and transported into the storage volume continuously during the complete process.

8. The method according to claim 1, wherein the vapor is transported from the direct evaporator to the process region via the storage volume by means of a carrier gas, wherein the supply of carrier gas is interrupted as long as the fluid connection between the storage volume and the process region is interrupted.

9. A method for filling a process region with vapor from a direct evaporator that is connected with the process region via a storage volume and a fluid connection, wherein the method comprises: evaporating a liquid in the direct evaporator for generating a vapor while the fluid connection between the storage volume and the process region is interrupted until a predetermined filling condition is met; restoring the fluid connection between the storage volume and the process region; and filling the process region with vapor.

10. The method according to claim 9, wherein the predetermined filling condition comprises one or a combination of the following conditions: reaching a predetermined evaporation rate; reaching a predetermined pressure and/or vapor volume in the storage volume.

11. The method according to claim 9, wherein the pressure in the storage volume is smaller than the vapor pressure of the liquid before evaporation begins.

12. The method according to claim 9, wherein the storage volume is heated during evaporation.

13. The method according to claim 9, wherein the process region is part of a coating machine.

14. An apparatus for providing vapor for a discontinuous process, the apparatus comprising: a direct evaporator for generating vapor; a storage volume in fluid connection with the direct evaporator; a temperature closed loop control by means of which the temperature of the storage may be closed loop controlled; a conduit by means of which the storage volume may be connected with a process region, wherein the conduit comprises a valve; and a control unit which is suitable and configured for controlling the direct evaporator and the valve such that: the valve is open and the generated vapor is transported from the direct evaporator to the process region via the storage volume if no vapor is required in the process region, the valve is closed if no vapor is required in the process region, and vapor continues to be generated at least temporarily during the interruption so that the pressure within the storage volume increases during the interruption.

15. The apparatus according to claim 14, wherein the control unit is further suitable and configured for controlling the temperature closed loop control such that the temperature of the storage volume is closed loop controlled during the interruption.

16. The apparatus according to claim 14, wherein the control unit is further suitable and configured for controlling the temperature closed loop control such that the temperature of the storage volume is at least so high during the interruption that no condensation of the vapor takes place within the storage volume during the interruption.

17. The apparatus according to claim 14, wherein vapor continues to be generated and transported into the storage volume continuously during the complete interruption.

18. The apparatus according to claim 14, further comprising a conduit for supplying a carrier gas, the conduit being interruptible by means of an additional valve, wherein the control unit is further suitable and configured for closing the additional valve as long as the fluid connection between the storage volume and the process region is interrupted.

19. The apparatus according to claim 14, wherein the storage volume and/or the conduit by means of which the storage volume may be connected with a process region comprises an inner cross-sectional area of at least 25 mm.sup.2.

20. The apparatus according to claim 14, wherein the apparatus is suitable for carrying out the method according to claim 1.

21. A coating machine for coating a substrate, wherein the coating machine comprises a process region and an apparatus according to claim 14, the conduit of which is connected with the process region.

Description

[0035] In the following, a preferred embodiment of the present invention is described with reference to the Figures. in which

[0036] FIG. 1 shows an apparatus for providing vapor for a discontinuous process according to a preferred embodiment.

[0037] FIG. 1 schematically shows an apparatus for providing vapor for a discontinuous process according to a preferred embodiment. The discontinuous process is carried out in the process region 7 (illustrated as well), which does not form part of the apparatus according to the invention. The apparatus comprises a direct evaporator 2 for generating a vapor from liquid which is provided to the direct evaporator 2 from a liquid metering device 1 via the conduit 12. The conduit 12 may be closed and opened by the valve 13. The apparatus further comprises a storage volume 5 in fluid communication with the direct evaporator 2 via a conduit 9. The temperature of the storage volume 5 may be closed loop controlled by the closed loop temperature control 4. The apparatus further comprises a conduit 8 by means of which the storage volume 5 may be connected with the process region 7, wherein a valve 6 is provided in the conduit 8. The apparatus further comprises a non-illustrated control unit which is suitable and configured for controlling the direct evaporator 2 and the valve 6 such that the valve 6 is open and the generated vapor is transported from the direct evaporator 2 to the process region 7 via the storage volume 5 if no vapor is required in the process region 7, and that vapor continues to be generated at least temporarily during the interruption so that the pressure within the storage volume 5 increases during the interruption.

[0038] In the embodiment shown in FIG. 1, the temperature closed loop control 4, which preferably comprises one or a plurality of heating elements, is configured such that not only the temperature of the storage volume 5 but also the temperature of the conduit 9 between the direct evaporator 2 and the storage volume 5 as well as of the conduit 8 between the storage volume 5 and the process region 7 may be closed loop controlled. In this way, it may be made sure that no vapor condensates in the complete area between the direct evaporator 2 and the process region 7.

[0039] In the illustrated preferred embodiment, the vapor is transported from the direct evaporator to the process region 7 via the storage volume 5 by a carrier gas. For this purpose, the apparatus comprises a conduit 10 for supplying a carrier gas, said conduit being interruptible by an additional valve 11. The volume flow of the carrier gas is preferably closed loop controlled by the constant flow controller 3.

[0040] Preferably, the non-illustrated control unit is also suitable and configured for closing the additional valve 11 as long as the fluid connection 8 between the storage volume 5 and the process region 7 is interrupted. It is further preferred that the control unit controls the liquid metering device 1 and/or the valve 13 in the conduit 12 and/or the constant flow controller 3 as well.

[0041] For instance, the liquid metering 1 may be carried out with the help of a mass flow controller for liquids, which uses thermal, Coriolis and/or ultrasonic measuring methods. Alternatively, a combination of a mass flow meter and a closed loop control valve or a dosing system and a dosing pump (e.g., micro annular gear pump, plunger pump, membrane pump) may be used. In the direct evaporator, the entire evaporation of the supplied liquid takes place by energy supply and temperature closed loop control. The closed loop control valve of the liquid metering device 1 may also be integrated into the direct evaporator 2 or into the conduit 12 (e.g., in the form of the valve 13 or as an additional closed loop control valve). Furthermore, the liquid metering device 1 and the direct evaporator 2, which are illustrated as separate units in FIG. 1, may also form a joint unit.

[0042] However, the invention is not limited to the arrangements shown in FIG. 1 or described above. Rather, other methods for metering and direct evaporation that are known to the skilled person may also be used.