DEVICE AND METHOD FOR FREEZE-DRYING

Abstract

The invention relates to a device and a method for freeze-drying products, wherein products are arranged in a drying chamber (2) for a freeze-drying process, wherein energy is supplied to the products arranged in the drying chamber (2) by means of microwaves at least during some parts of the freeze-drying process, and wherein the microwaves are generated by at least one microwave module (6) based on semiconductor technology. The invention also relates to the use of a microwave module (6) based on semiconductor technology in a freeze-drying process.

Claims

1. A device for freeze-drying products having a drying chamber in which products can be arranged for a freeze-drying process, wherein a microwave module based on semiconductor technology is provided, by means of which microwaves can be generated for supplying energy to the products arranged in the drying chamber during the freeze-drying process.

2. The device as claimed in claim 1, wherein the microwave module comprises at least one microwave control unit, at least one microwave generator and at least one microwave antenna based on semiconductor technology.

3. The device as claimed in claim 2, wherein the at least one microwave antenna is arranged in the drying chamber.

4. The device as claimed in claim 3, wherein at least one shelf (5) is provided in the drying chamber, on which the products are placed for a freeze-drying process, the at least one microwave antenna being arranged adjoining to the at least one shelf, in particular on a flat side of the at least one shelf.

5. The device as claimed in claim 2, wherein the at least one microwave generator and the at least one microwave control unit are arranged outside the drying chamber.

6. The device as claimed in claim 2, wherein the at least one microwave control unit is connected to a higher-level control system and at least one lower-level microwave generator for signal transmission.

7. The device as claimed in claim 2, wherein the at least one microwave generator is connected to at least one microwave antenna for signal transmission, wherein an output power and/or an output frequency of the at least one microwave antenna connected for signal transmission is adjustable by means of the at least one microwave generator.

8. The device as claimed in claim 7, wherein the output power and/or the output frequency of the at least one microwave antenna can be adjusted incrementally and/or continuously during operation of the device.

9. The device as claimed in claim 7, wherein the at least one microwave generator is connected to a plurality of microwave antennas for signal transmission, wherein output powers and/or output frequencies of the plurality of microwave antennas connected for signal transmission are adjustable independently of one another by means of the microwave generator.

10. The device as claimed in claim 2, wherein the at least one microwave control unit is connected to a plurality of microwave generators for signal transmission.

11. The device as claimed in claim 1, wherein a condenser chamber with a condenser is provided, wherein the drying chamber and the condenser chamber are arranged relative to each other so as to prevent or at least minimize the coupling of microwaves into the condenser chamber.

12. A method for freeze-drying products, wherein products are arranged in a drying chamber for a freeze-drying process, wherein energy is supplied to the products arranged in the drying chamber by means of microwaves, at least during parts of the freeze-drying process, wherein the microwaves are generated by means of a microwave module based on semiconductor technology, comprising at least one microwave antenna based on semiconductor technology.

13. The method as claimed in claim 12, wherein an output power and/or an output frequency of the at least one microwave antenna is varied during at least some parts of the freeze-drying process.

14. The method as claimed in claim 13, wherein microwaves are emitted by means of a plurality of microwave antennas based on semiconductor technology, wherein output powers and/or output frequencies of the microwave antennas are adjusted independently of each other at least during parts of the freeze-drying process.

15. Use of at least one microwave module based on semiconductor technology for generating microwaves for supplying energy to products in a freeze-drying process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Further advantages and aspects of the invention are derived from the claims and from the following description of preferred exemplary embodiments of the invention, which are explained below by reference to the figures. In the drawings:

[0048] FIG. 1: shows a schematic view of a first exemplary embodiment of a device for freeze-drying according to the invention;

[0049] FIG. 2: shows a schematic view of a second exemplary embodiment of a device for freeze-drying according to the invention; and

[0050] FIG. 3: shows a schematic view of a third exemplary embodiment of a device for freeze-drying according to the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0051] FIG. 1 shows a schematic view of a device 1 for freeze-drying, comprising a drying chamber 2 and a condenser chamber 3 with a condenser 30. In the exemplary embodiment shown, the drying chamber and the condenser chamber 3 are connected via an intermediate valve 4. In other designs, no intermediate valve 4 is provided. In other designs again, the condenser 30 is arranged in the drying chamber 2.

[0052] A plurality of shelves 5 are provided in the drying chamber 2, wherein four shelves 5 are shown in FIG. 1 as an example. However, the number of shelves 5 can vary depending on the application. Products that are to undergo the freeze-drying process are placed on the shelves 5 in vials, for example (not shown).

[0053] Device 1 also comprises a microwave module 6 based on semiconductor technology, having a plurality of microwave antennas 60, a microwave generator 62 and a microwave control unit 64.

[0054] In the exemplary embodiment shown, only one microwave generator 62 is provided, wherein the microwave antennas 64 are each connected to the microwave generator 62 for signal reception. The number and arrangement of the microwave antennas 62 connected to the microwave generator 62 can be selected by the person skilled in the art according to the requirements. In one design, all microwave antennas 64 provided in a device 1 are designed identically. In other designs, the microwave antennas 64 of a device 1 —as shown in FIG. 1—are designed differently. In a different design, a plurality of microwave generators 62 are provided, wherein the number and/or arrangement of the microwave antennas 64 connected to a microwave generator 62 can be different. The microwave generator 62 is controlled by means of the microwave control unit 64. If a plurality of microwave generators 62 are provided, these can each be assigned to a separate microwave control unit 64 or assigned to a central microwave control unit 64 in groups or in their entirety.

[0055] In the exemplary embodiment shown in FIG. 1, the microwave antennas 60 are each arranged adjoining to a shelf 5, below the shelf 5. In one design, a microwave antenna 60 is assigned to each shelf 5. In other designs—as shown in FIG. 1—microwave antennas 60 are provided only on some of the shelves 5.

[0056] In the design shown in FIG. 1, the microwave antennas 60 are connected to the microwave generator 62 via conductors, such as cables, for example. In other designs, a signal transmission can also be implemented wirelessly, for example. The implementation of the signal transmission via cables—as shown in FIG. 1—between the individual microwave antennas 64 and the microwave generator 62 allows the transmission of power-related electromagnetic signals from the microwave generator 62 to the microwave antennas 64. An output power and/or an output frequency can be adjusted by means of the microwave generator 62 and the microwave antennas 64 therefore emit microwaves with a defined power and/or frequency in the drying chamber 2.

[0057] The microwave generators 62 are connected to the microwave control unit 64 wirelessly and/or using conductors, via a communication interface in each case.

[0058] The microwave control unit 64 communicates information to the microwave generator 62 as to how the output power and/or an output frequency of the microwave antennas 64 should be adjusted. To do this, in one design the output powers and/or output frequencies of all microwave antennas 64 are adjusted separately. In other designs, a group-by-group adjustment occurs, wherein microwave antennas 64 in a group are connected to one microwave generator 62 or are distributed over more than one microwave generator 62.

[0059] The device 1 preferably comprises further devices known from conventional devices for freeze-drying, not described further, such as a cooling/heating module for temperature control of the shelves 5 and/or a heat exchanger of the condenser 30, a vacuum module for evacuating the drying chamber 2 and/or a ventilation system, which is used, for example, both for ventilation of the device 1 and adjustment of the pressure during the freeze-drying process.

[0060] The device 1 comprises a higher-level control system 8, wherein, in the exemplary embodiment shown, the microwave control unit 64 is connected to the higher-level control system 8 for the exchange of data and/or control signals.

[0061] For example, the higher-level control system 8 is designed as a SCADA system. In particular, it is used to control and monitor relevant process steps of the freeze-drying process, including subsidiary process steps, such as automatic cleaning and sterilization.

[0062] The freeze-drying process comprises, for example, the following process steps:

[0063] 1. Load product

[0064] 2. Cool, freeze and under-cool the product to a specific temperature

[0065] 3. Evacuate down to a defined pressure

[0066] 4. Heat the product to a defined temperature

[0067] 5. Seal the product (necessary if the product has been freeze-dried in sealable containers, e.g. glass vessels with stoppers)

[0068] 6. Unload product

[0069] 7. Prepare the freeze-dryer for the next process.

[0070] According to the invention, at least during parts of the freeze-drying process, energy is supplied to the products arranged in the drying chamber 2 via microwaves generated by means of the microwave module 6 based on semiconductor technology, which comprises at least one microwave antenna 64 based on semiconductor technology. Depending on the application, the energy supply can, for example, replace or supplement an energy supply by conventional temperature control of the shelves 5.

[0071] Preferably, energy is supplied by means of radiant heat input from the microwaves, at least for heating the products under vacuum.

[0072] FIGS. 2 and 3 show two further exemplary embodiments of devices 1 for freeze-drying with semiconductor-technology based microwave antennas 64 for generating microwaves to supply energy to products present in drying chambers 2.

[0073] The devices 1 according to FIGS. 2 and 3 are similar to the device 1 according to FIG. 1. Corresponding reference signs are used for identical or similar components and for a description, refer to the text above.

[0074] The microwave antennas 64 here are also each connected to at least one microwave generator 62. In contrast to the design according to FIG. 1, in the devices 1 according to FIG. 2, the microwave antennas 62 are arranged above the shelves 5, adjoining to them. In the case of the devices 1 according to FIG. 3, the microwave antennas 64 are arranged both above and below the shelves 5 and adjoining to them.

[0075] In the exemplary embodiment shown in FIG. 3, a plurality of microwave antennas 64 are provided on a shelf 5, in the drawing the lowest shelf 5, which are arranged both above and below the lowest shelf 5. Each of these microwave antennas is separately connected to the microwave generator 62. The illustration represents only one example. In an alternative design, a plurality of microwave antennas 64 may also be provided on some or all of the shelves 5.

[0076] In all the exemplary embodiments shown, the microwave antennas 64 are arranged in a drying chamber 2 and connected for signal reception to at least one microwave generator 62 located outside the drying chamber 2. The microwave antennas 64 in this case are mounted on or under the shelves 5. This design is advantageous because it is simple to assemble. In addition, it is possible to equip already existing devices in the same way using the microwave antennas 64. However, other designs are also possible, in which the microwave antennas 64 are integrated, for example, in the shelves 5 and/or in wall elements of the drying chamber 2.

[0077] The exemplary embodiments illustrated are merely examples and do not limit the subject matter defined by the claims. In particular, the size of the drying chamber 2 and the number of shelves 5, as well as the arrangement and number of microwave antennas 64 on the shelves 5, the number of microwave generators 62 and their connection to the microwave antennas 64, and the number of microwave control units 64 are only examples.