EP1502063B1 - Freeze-drying device - Google Patents

Abstract

A drying unit for removing solvent from moist material, and a method for drying moist material with the drying unit. The unit comprises at least one drying chamber ( 23 ) having at least one stand plate ( 2 ) for holding vessels ( 3 ), which are filled with moist material, or flat layers of moist material, the drying chamber ( 23 ) being connected to a condenser ( 22 ) via a vapor passage ( 15 ), in which sublimed solvent can be separated out, the stand plates ( 2 ) being connected to a temperature-controlled heating/cooling circuit, the chamber ( 23 ) having heating/cooling plates ( 4 ) or ( 4 ') which are connected to a second heat-transfer circuit, wherein the heating/cooling plates ( 4 ) or ( 4 ') are substantially thermally isolated from the chamber wall ( 6 ).

Description

The invention relates to a freeze-drying chamber with coolable / heatable shelves for a variety of produktgefiillten containers or assignable with product layers cool / heatable control panels with special facilities that eliminate the drying progress dependent harmful temperature influences the chamber wall surfaces. Special versions allow the avoidance of high energy loss through a special chamber wall construction with simultaneous mass reduction of the tempered components

When drying in known freeze-drying chambers with a variety of shelves for product-filled containers or even product layers, the containers or product layers in the edge region of the panels by radiation heat exchange and natural convection in the gap between the wall and stack of stacks have a more intensive energy exchange than the container / product layers positioned in the middle of the plate. This inhomogeneity of the energy distribution leads to different freezing and drying kinetics when comparing containers arranged at the edge and in the middle, or product layers.

The avoidance of inhomogeneity is achieved by eliminating the driving potential responsible for the irregularities. Driving potential for drying are temperature differences between product-filled containers or product layers and their environment, which provides the potential necessary for the progress of freeze-drying. This potential is greater in the edge region of the control panels than in the middle of the control panel, because direct heat exchange by radiation and convection takes place between containers at the edge and the chamber wall. During the freezing process according to the prior art (at normal or slightly reduced pressure), the natural convection of the gas in the free gap between wall and temperature-controlled control panels acts particularly strongly as a heat carrier for the convection current exposed container. These additional heat flows decrease towards the center of the plate and thus cause the inhomogeneous freezing and drying process of the containers or product layers distributed over the plate.

Freeze dryers are made according to the prior art either entirely without tempering the chamber walls or with heating / Kühlinäntelt which are applied directly to the supporting structure. These heating / cooling jackets have the purpose of the chamber to cool down from the sterilization temperature to the temperature suitable for loading because of the short to ground with the heavy supporting structure of the chamber. Thereafter, the coolant is usually emptied from these heating / cooling surfaces to reduce mass. The cooling of the chamber wall to a temperature which eliminates the driving potential responsible for the disturbance is not possible with these constructions.

1. 1. Die zusätzlichen Kühlflächen sind in die mechanische Tragkonstruktion des Trockners integriert, die für eine Evakuierung hinreichend armiert sein muss. Dies bewirkt den Nachteil, im Betrieb des Trockners große Massen heizen/- kühlen zu müssen. Daher reagiert der Trockner notwendigerweise thermisch träge.
2. 2. Die Regelung entsprechend US-A-5 398 426 , nämlich der Gleichheit von Wand- und Stellflächentemperatur, führt besonders während des ersten Trocknungsabschnitts, der Sublimationstrocknung, nicht zu der gewünschten Beseitigung des für die Störung verantwortlichen treibenden Potenzials und daher auch nicht zur Beseitigung von Inhomogenitäten speziell während der Sublimationstrocknung. Dieses Problem wird zwar durch den Trockenapparat gemäß JP-A-02169984 gelöst, indem die Kühlflächen von der Außenwand beabstandet angebracht wurden, jedoch tritt auch hier eine starke Ungleichmäßigkeit der Kühlung auf, weil die Kühlflächen nicht die gesamte Fläche der Stellplatten erfassen.

In Scripture US-A-5,398,426 describes a freeze dryer, the chamber walls are cooled to eliminate the same temperature differences of chamber walls and panels the disturbing temperature differences. This construction has two disadvantages:

1. 1. The additional cooling surfaces are integrated into the mechanical support structure of the dryer, which must be adequately armored for evacuation. This has the disadvantage of having to heat / cool large masses during operation of the dryer. Therefore, the dryer necessarily reacts thermally inert.
2. 2. The regulation accordingly US-A-5,398,426 namely the equality of wall and shelf temperature, especially during the first drying section, the sublimation drying, does not result in the desired elimination of the driving potential responsible for the disturbance and therefore also not in the removal of inhomogeneities, especially during sublimation drying. Although this problem is due to the drying apparatus according to JP-A-02169984 solved by the cooling surfaces are mounted spaced from the outer wall, but also occurs here a strong unevenness of cooling, because the cooling surfaces do not cover the entire surface of the adjusting plates.

• Beseitigung der Ungleichmäßigkeit zwischen Rand- und Mittenbereich der Stellplatten die bei dem Einfrieren und Trocknen von produktgefüllten Behältern zu ungleichen Temperatur-und Trocknungsverläufen der Behälter führt.

The invention is therefore based on the following tasks:

• Elimination of non-uniformity between the edge and center areas of the panels, which leads to uneven temperature and drying characteristics of the containers during the freezing and drying of product-filled containers.

The elimination of the non-uniformity is achieved by controlled heating / cooling plates, which surround the control panels like a radiation cage, which are adjusted so that there is no driving temperature gradient between wall and container. The resulting homogeneity of the freezing and drying process of all containers, the uniformity of the product quality and the drying capacity can be significantly increased.

The invention relates to a drying apparatus for removing solvent from moist material, comprising at least one drying chamber with at least one adjusting plate for receiving wet-filled containers or layers of moist material, wherein the drying chamber is connected to a condenser via a vapor channel in which the sublimated solvent is separable, wherein the control panels are connected to a temperature-controlled heating / cooling circuit, the chamber having heating / cooling plates, which are connected to a second heat transfer circuit and wherein the Heating / cooling plates are carried out largely thermally decoupled from the chamber wall, characterized in that the heating / cooling plates are suspended parallel to the edges of the adjusting plates at a distance from the adjusting plates in the drying chamber, so that the hanging heating / cooling plates a nearly closed Form radiation cage around the stack of piles.

The elimination of the non-uniformity is achieved by controlled heating / cooling plates, which surround the control panels like a radiation cage, which are adjusted so that there is no driving temperature gradient between wall and container. The resulting homogeneity of the freezing and drying process of all containers can improve the uniformity of the product quality and significantly increase the drying capacity.

In order to allow temperature control, the control panels can be provided with a piping system. The pipe system is traversed by a stream of temperature-controlled heat transfer medium, which is supplied from a heating / cooling system.

A preferred drying apparatus is characterized in that the heating / cooling plates are spaced from the chamber wall.

Particularly preferably, the outer chamber wall is pressure-resistant, so that the surface forces are absorbed without deformation during evacuation of the chamber.

Also preferred is a drying apparatus wherein the outer chamber wall has thermal insulation to minimize energy loss of the system.

Also preferred is a drying apparatus in which the heating / cooling plates are vacuum-tightly connected to the chamber wall, so that effectively results in a 2-chamber system

The heating / cooling surfaces are mechanically connected in particular via spacers with the inside of the chamber wall and form with this an evacuated planar gap. Here, vacuum connections are provided in the chamber wall.

Preference is furthermore a drying apparatus, characterized in that the gap is adjustable by a vacuum system to the pressure level of the drying chamber for the purpose of pressure equalization.

The spacers are preferably made of poorly heat-conducting material, in particular stainless steel.

A particular embodiment of the drying apparatus is characterized in that elastic connecting plates between the side heating / cooling plates and the chamber wall are designed so flexible that the temperature-induced changes in length of the heating / cooling surfaces are compensated without material damage.

In a preferred further embodiment of the drying apparatus, the drying chamber is already evacuated during the freezing process in order to reduce convection influences.

The chamber wall has a special design on an external heat insulation.

In a preferred drying apparatus, the CIP / SIP devices are mounted so that all surfaces can be cleaned.

Preferably, a drying apparatus, characterized in that the temperature control systems for the heating / cooling plates are sensor-controlled to the appropriate temperature adjustable.

In a variant of the preferred drying apparatus, the temperature control systems for the heating / cooling plates are predictively controlled by a computer program controlled to the appropriate temperature.

In a further preferred variant of the drying apparatus, the temperature control systems for the heating / cooling plates are controlled by a hybrid system of sensor and computer and set to the appropriate temperature.

The inventive arrangement of the heating / cooling plates equal mass ratios between heating / cooling plates and control panels are made and thus allows approximately the same temperature / time profiles for walls and panels / container.

The regulation of the heating / cooling plates follows the following strategy:

Due to temperature equality of walls and excluding control panels (as in US-A-5,398,426 described) this disorder can be reduced, but not eliminated. Rather, the wall temperatures during freeze-drying must essentially be adjusted to the vial temperature ( Fig. 3.b ) to almost completely eliminate the disturbances. This effect is achieved by eliminating the disturbing temperature difference between chamber wall and container / panels. Containers and control panels do not have the same temperature during the first dry section, so a mixing temperature of tank and platen temperature must be set for the wall temperature. This mixing temperature is expediently determined with the aid of a simulation program on the basis of a predetermined lyocycle (temperature, pressure and time profile).

The solution to this problem is achieved by installing the above-described separately temperature-controlled heating / cooling surfaces surrounding the control panels on all four sides, so that an almost closed radiation cage is formed. By eliminating the temperature differences between heating / cooling plates and shelves / container is also the emergence of disturbing free convection with their heat supply to the marginal containers or the product layer at the edge of the plate - especially at Einfrierschritt (here the free convection at ambient pressure particularly strong) - prevented. During freeze-drying at low system pressures, however, free convection plays a rather minor role.

The regulation / control of the heating / cooling plate temperature can be carried out according to the following strategies:

Sensor-controlled control : During the freezing phase, the control panels and heating / cooling plates are controlled following the same temperature program. After the start of the drying program, the heating / cooling plate temperature and the plate temperature follow different programs. The platen temperature is determined by the given Lyozyklus and it is traversed and regulated in the Lyozyklus specified temperature / Zeitprogamm. The temperature of the heating / cooling plates is set in the first drying section on the sublimation of the frozen product, which adjusts chamber pressure-dependent and solvent-dependent. As a first approximation, this temperature can be calculated on the basis of the material values. Measurements of the sublimation temperature in the laboratory experiment can be used to correct this calculated temperature. It is also possible to use the pressure rise method for the direct determination of the sublimation temperature, as described, for example, by GW Oetjen in "Gefriertrocknen", VCH Verlag, 1997.

The temperature of the heating / cooling plates must be changed when the second drying section starts. The beginning of the second drying section can be detected by measuring the system pressure in the gas stream from the freezing chamber with different pressure measuring probes, eg: an absolute pressure gauge and a conductivity probe (eg Pirani probe) set to nitrogen. If the solvent vapor flow approaches 0 at the end of the first drying section, both measured values approach the same value, since the nitrogen content in the gas flow increases steadily and thus the measured value of the Pirani probe approaches more and more the absolute pressure measured value. The temperature of the heating / cooling plates can now be slowly raised to the plate temperature and be tracked in the further course of drying the platen temperature. For example, the degree of approach to the platen temperature is determined as a function of the pressure difference between the two pressure readings.

Predictive control of the heating / cooling plates : If, in the laboratory test, drying characteristics were recorded on the product to be dried under defined conditions and a drying program was used to determine all freeze drying properties / parameters of the product, the drying process can be determined with knowledge of the freeze drying properties of the freeze dryer of the product and the values of the product temperature determined by the calculation program are used as the reference variable for the heating / cooling plate temperatures. This method is in Fig. 3b shown.

Hybrid method: From the measurements in the freeze dryer (absolute pressure, pressure according to conductivity probe) and simulation calculations, the product temperatures are determined and used as a reference variable for the heating / cooling plate temperature.

• Sterilisieren, gegebenenfalls Heißsterilisieren der Kammer inklusive der unbelegten Stellplatten,
• Beladen der Stellplatten mit Feuchtgut oder Feuchtgut enthaltenden Behältern
• Schließen der Kammeröffnung und Abkühlen der Stellplatten,
• Gleichzeitiges Abkühlen der Heiz-/Kühlplatten,
  anschließendes Evakuieren und Durchfahren eines Temperaturprogrammes zur schrittweisen Erwärmung der Stellplatten und gleichzeitiger allmählicher Anpassung
  der Temperatur der Heiz-/Kühlplatten an die Temperatur der Behälter bzw. des Feuchtgutes,
• Belüften der Vorrichtung mit sterilem Gas,
• Einstellen der Temperatur der Stellplatten und der Heiz-/Kühlplatten auf Entladetemperatur, gegebenenfalls auf die Umgebungstemperatur, gegebenenfalls verschließen der Behälter und Entnahme der Behälter oder des Trockengutes.

The invention also provides a process for drying moist material using a drying apparatus according to the invention, comprising the steps of:

• Sterilization, if necessary, sterilizing the chamber, including blank panels, if necessary
• Loading the control panels with wet or moist containers
• Closing the chamber opening and cooling the control panels,
• Simultaneous cooling of the heating / cooling plates,
  subsequent evacuation and passing through a temperature program for the step-by-step heating of the control panels and, at the same time, gradual adaptation
  the temperature of the heating / cooling plates to the temperature of the containers or of the moist material,
• Aerating the device with sterile gas,
• Setting the temperature of the control panels and the heating / cooling plates at discharge temperature, possibly to the ambient temperature, if necessary, close the container and remove the container or the dry material.

Fig. 1

den typischen Aufbau einer Gefriertrockungskammer nach dem Stand der Technik mit Kondensator, Stellplatten und wandintegrierten Heiz-/Kühlplatten, die an einen separat regelbaren Heiz-/Kühlkreislauf angeschlossen sind und deren Zwischenraum zwischen mechanisch steifem, schweren Wandaufbau und Heiz-/Kühlplatten evakuiert werden kann;

Fig. 1a

einen horizontalen Schnitt durch die Gefriertrocknungskammer nach Fig. 1 mit wandintegrierten Heiz-/Kühlplatten;

Fig. 2

eine Variante der erfindungsgemäßen Gefriertrocknungskammer mit Heiz/Kühlplatten, die senkrecht vor die Stellplattenstapel gehängt werden und an einen separat regelbaren Heiz-/Kühlkreislauf angeschlossen sind;

Fig. 3a

den Temperaturverlauf von Behälter, die am Rand bzw. in der Mitte der Stellplatte stehen, bei ungeregelter Wandtemperatur;

Fig. 3b

den Temperaturverlauf der Behälter, die am Plattenrand bzw. in der Mitte der Stellplatte stehen, bei erfindungsgemäß geregelter Wandtemperatur;

Fig. 3c

den Temperaturverlauf der Behälter, die am Plattenrand bzw. in der Mitte der Stellplatte stehen, wenn die Wandtemperatur gemäss US-A-5,398,426 geregelt wird;

Fig. 4

Berechnungen zum Temperaturverlauf bei randständigen und in der Mitte der Stellplatte 2 angeordneten Behältern 3.

In the figures, the new freeze-drying device is shown purely schematically and explained in more detail below by way of example. Show it:

Fig. 1

the typical structure of a freeze-drying chamber according to the prior art with capacitor, control panels and wall-integrated heating / cooling plates, which are connected to a separately controllable heating / cooling circuit and the space between mechanically stiff, heavy wall construction and heating / cooling plates can be evacuated;

Fig. 1a

a horizontal section through the freeze-drying chamber after Fig. 1 with wall-integrated heating / cooling plates;

Fig. 2

a variant of the freeze-drying chamber according to the invention with heating / cooling plates, which are hung vertically in front of the stack of stacks and are connected to a separately controllable heating / cooling circuit;

Fig. 3a

the temperature profile of containers, which are at the edge or in the middle of the table, at unregulated wall temperature;

Fig. 3b

the temperature profile of the container, which are at the edge of the plate or in the middle of the control plate, according to the invention controlled wall temperature;

Fig. 3c

the temperature profile of the containers, which are at the edge of the plate or in the middle of the table, if the wall temperature according US-A-5,398,426 is regulated;

Fig. 4

Calculations on the temperature profile at marginal and in the middle of the adjusting plate 2 arranged containers. 3

Examples

In Fig. 1 For example, a conventional system of freeze-drying chamber 1 and condenser chamber 22 is shown in which packages of product-filled containers are frozen and freeze-dried. In Fig. 1a Container 3 are indicated on the shelf 2 in the edge and middle area standing. The chamber 1 has two separately openable doors 11, 11a, which are sealed. The freeze-drying chamber 1 has a bivalve structure. The heavy chamber wall construction 6 with reinforcing ribs 7 has the task of offering a vacuum-tight, torsionally stiff housing, which withstands atmospheric pressure during evacuation of the freeze-drying chamber 1, for the second, inner chamber 23 integrated therein. The chamber 1 is equipped with thermal insulation material 8 on its outside against heat exchange with the environment. The inner freeze-drying chamber 23 is formed from the heating / cooling plates 4, which are held by means of spacers 5 at a distance from the chamber wall 6, pressure-tight connected via flexible sheets 9 with the chamber wall 6, so that the gap 24 between heating / cooling plates and supporting wall 6 of the chamber 1 can be evacuated. The evacuation takes place via pipelines 10, 12, which are connected to the main vacuum pump 21 via valves 20. The evacuation of the gap 24 serves two purposes: First, the pressure equalization between freeze-drying chamber 23 and the space 24 between heating / cooling plates 4 and chamber wall 6, so that pressure forces on the heating / cooling plates 4 are avoided. Second, it serves to lower the heat exchanger by the pressure-dependent lowering of the effective heat conduction of the intermediate space 24. During the drying phase prevails in the space 24, the same pressure as in the freeze-drying chamber 23 (p <0.1 mbar), so that the gap 24 as the evacuated Gap of a Dewar flask acts. The spacers 5 between the heating / cooling plates 4 and the chamber wall 6 are made of a poorly heat-conductive material (eg stainless steel), and the number of spacers 5 is minimized to the necessary extent, so that the heat transfer is minimized by heat conduction through the spacers 5 ,

The connecting plates 9 are structurally designed so that the temperature-dependent change in length of the heating / cooling plates 4 can be absorbed by the sheets without risk to the mechanical strength of the connection to the chamber wall 6. In this way, a smooth-surface freeze-drying chamber 23, which can be easily cleaned. The heating / cooling plates 4 are supplied via a separately controllable temperature control (not shown) with heat transfer fluid (silicone oil), which is discharged via the line 13 and line 14. The temperature control system uses the same heat transfer medium as the control panels and can be supplied from the same reservoir. The temperature control system for the heating / cooling plates 4 must always be operated with a temperature adjusted to the vial temperature, while the heat transfer medium for the control plates 2 follows another temperature program following the Lyo cycle.

The temperature program for the heating / cooling plates 4 depends on the temperature of the container. This method is already described in general above.

Example 2

In Fig. 2 another embodiment of the freeze dryer with respect to the attachment of heating / cooling plates 4 'is shown. Here, the tempered plates 4 'hang freely in the chamber 23. The heating / cooling plates 4' are suspended parallel to the edges of the panels 2 at a distance, so that space for all the panels 2 associated organs eg tubes 25, 26 for the Heat transfer medium, shelf holder (not shown), is maintained.

Known CIP / SIP devices (automatic cleaning and sterilization systems) can also be provided in the chamber interior. The heating / cooling plates 4 'are in turn fed by a separate heat transfer circuit via inlet 13 and return 14 with the heat transfer medium. The crowd the heating / cooling plates corresponds in both cases (according to Example 1 and 2) of the mass of the adjusting plates 2, so that the heating / cooling dynamics of the plates 2 and 4 or 4 'are matched and no temperature shifts caused by mass inequality.

Calculations on the temperature profile:

Fig. 3a

zeigt den Temperaturverlauf der Behälter, die am Rand bzw. in der Mitte der Stellplatte stehen, bei ungeregelter Wandtemperatur; hierin bezeichnen die Kürzel:

• a ungeregelte Wandtemperatur
• b Stellenplattentemperatur
• c Randbehältertemperatur
• d Mittenbehältertemperatur
  die Indices 1 stehen hier wie in den nachfolgenden Diagrammen für die Temperatur auf 1 mm Kuchenhöhe des Trocknungsgutes und Indices 6 für die Temperatur auf 6 mm Kuchenhöhe des Trocknungsgutes;

Fig. 3b

den Temperaturverlauf der Behälter, die am Plattenrand bzw. in der Mitte der Stellplatte stehen, bei erfindungsgemäß geregelter Wandtemperatur; hierin bezeichnen die Kürzel:

• a geregelte Wandtemperatur
• b Stellplattentemperatur
• c Randbehältertemperatur
• d Mittenbehältertemperatur;

Fig. 3c

den Temperaturverlauf der Behälter, die am Plattenrand bzw. in der Mitte der Stellplatte stehen, wenn die Wandtemperatur gemäss US-A-5,398,426 geregelt wird; hierin bezeichnen die Kürzel:

• a geregelte Wandtemperatur
• b Stellplattentemperatur
• c Randbehältertemperatur
• d Mittenbehältertemperatur.

For the temperature profile in different variants of the freeze-drying device calculations are performed, which in the diagrams according to 3a to 3c and 4 are reproduced.

Fig. 3a

shows the temperature profile of the containers, which are at the edge or in the middle of the table, at unregulated wall temperature; Here the abbreviations designate:

• a unregulated wall temperature
• b hotplate temperature
• c edge tank temperature
• d center tank temperature
  the indices 1 are here as in the following diagrams for the temperature to 1 mm cake height of the material to be dried and indices 6 for the temperature to 6 mm cake height of the material to be dried;

Fig. 3b

the temperature profile of the container, which are at the edge of the plate or in the middle of the control plate, according to the invention controlled wall temperature; Here the abbreviations designate:

• a controlled wall temperature
• b control plate temperature
• c edge tank temperature
• d center tank temperature;

Fig. 3c

the temperature profile of the containers, which are at the edge of the plate or in the middle of the table, if the wall temperature according US-A-5,398,426 is regulated; Here the abbreviations designate:

• a controlled wall temperature
• b control plate temperature
• c edge tank temperature
• d center tank temperature.

It can immediately be seen from the diagrams that, when the device according to the invention with controlled wall temperature is used, the temperature behavior of the edge-side containers substantially equals the behavior of the containers arranged centrally on the positioning plate ( Fig. 3b ) while operating conventional devices significant differences in the temperature profile occur ( Fig. 3a ); also in accordance with regulation of the wall temperature accordingly US Pat. No. 5,398,426 (3c).

• für die im Zentrum angeordneten Vials wird keine Wärmeübertragung durch die strahlende Wand berücksichtigt,
• für die am Rand positionierten Vials wird der vollständige Wärmeaustausch mit der Wand berücksichtigt.

In FIG. 4 the data of one experiment are shown in a 1 m ² pilot freeze drier (1 m ² footprint). All thin lines are measured values. The thick lines are calculated values. Opposite were the temperature profiles of containers 3, which are at the edge of the plate and temperature profiles of containers 3, which were in the center of the plate - far away from the wall and protected by the neighboring containers - were arranged. The calculated temperature profiles distinguish two cases:

• for the vials arranged in the center, no heat transfer through the radiating wall is considered,
• for the vials positioned at the edge, the complete heat exchange with the wall is considered.

a

Stellplattentemperatur

b

berechnete Wandtemperatur

b_1,2,3

gemessene Wandtemperaturen

c

Kammerdruck (gemessen)

d

Mittebehältertemperatur (gemessen)

e

Mittebehältertemperatur (berechnet)

f

Randbehältertemperatur (gemessen)

g

Randbehältertemperatur (berechnet).

The wall itself is in heat exchange with the control panels 2 and the environment and is therefore considered to be temporally variable. The agreement of the calculated temperatures with the measured temperatures can be considered satisfactory, taking into account the difficulties of temperature measurement in the containers. From this measurement and the evaluation by the simulation program can be deduced that even the marginal container 3 will follow the temperature profile of the container in the center when eliminating the driving temperature potential between wall and 2 adjusting plates, as shown in the diagram Fig. 3b was calculated for another case; in Fig. 4 the abbreviations a to g mean:

a

Shelf temperature

b

calculated wall temperature

b _1,2,3

measured wall temperatures

c

Chamber pressure (measured)

d

Center tank temperature (measured)

e

Center tank temperature (calculated)

f

Edge tank temperature (measured)

G

Border tank temperature (calculated).

Claims (13)

1. A drying unit (1) for removing solvent from moist material, comprising at least one drying chamber (23) with at least one stand plate (2) for receiving vessels (3) filled with moist material or level layers of moist material, said drying chamber (23) being connected to a condenser (22) via a vapor passageway (15) in which the sublimated solvent can be precipitated, said stand plates (2) being connected to a first temperature-regulated heating/cooling circuit, said chamber (23) comprising heating/cooling plates (4) or (4') that are connected to a second heat carrier circuit, said heating/cooling plates (4) or (4') being implemented so as to be widely thermally decoupled from the chamber wall (6),
   characterized in
   that the heating/cooling plates (4') are hung in the drying chamber (1) parallel to the edges of the stand plates (2) and at a distance from said stand plates (2) so that the suspended heating/cooling plates (4') form an almost closed radiation cage about the stack of stand plates.
2. The drying unit as set forth in claim 1,
   characterized in
   that the heating/cooling plates (4) or (4') are spaced away from the chamber wall (6).
3. The drying unit as set forth in any one of the previous claims,
   characterized in
   that the heating/cooling plates (4) are connected in vacuum-tight fashion to the chamber wall (6).
4. The drying unit as set forth in any one of the previous claims,
   characterized in
   that the heating/cooling surfaces (4; 4') are mechanically connected to the inner side of the chamber wall (6) via spacers (5) and form with said inner side of the chamber wall a level gap that may be evacuated. Vacuum connections are hereby provided in the chamber wall (6).
5. The drying unit as set forth in any one of the previous claims,
   characterized in
   that the gap can be adjusted to the pressure level of the drying chamber via a vacuum system for the purpose of pressure equalization.
6. The drying unit as set forth in any one of the previous claims,
   characterized in
   that the spacers (5) are made from a material having poor heat-conducting properties, in particular from stainless steel.
7. The drying unit as set forth in any one of the previous claims,
   characterized in
   that elastic connecting sheets (9) between lateral heating/cooling plates (4; 4') and the chamber wall (6) are configured to be so flexible that the temperature-related length variations of the heating/cooling surfaces are compensated without damage to the material.
8. The drying unit as set forth in any one of the previous claims,
   characterized in
   that the drying chamber (23) may be evacuated already during the freezing process in order to reduce convection influences.
9. The drying unit as set forth in any one of the previous claims,
   characterized in
   that the devices for CIP/SIP are mounted so that all the surfaces can be cleaned.
10. The drying unit as set forth in any one of the previous claims,
    characterized in
    that the temperature-control systems for the heating/cooling plates can be set to the appropriate temperature under sensor control.
11. The drying unit as set forth in any one of the previous claims,
    characterized in
    that the temperature-control systems for the heating/cooling plates can be set predictively to the appropriate temperature under control of a computing program.
12. The drying unit as set forth in any one of the claims 1 through 9,
    characterized in
    that the temperature-control systems for the heating/cooling plates can be set to the appropriate temperature through a hybrid system consisting of sensor and computer.
13. A method for drying moist material using a drying unit (1) as set forth in any one of the claims 1 through 12, with the steps:

    sterilizing, at need hot sterilizing, the chamber (23) inclusive of the empty stand plates (2),

    loading said stand plates (2) with moist material or with vessels (3) holding moist material

    closing the chamber opening and cooling the stand plates (2)

    whilst simultaneously cooling the heating/cooling plates (4, 4'),

    then, evacuating and carrying out a temperature program for stepwise heating of the stand plates (2) and concurrent progressive adaptation of the temperature of the heating/cooling plates (4, 4') to the temperature of the vessels (3) or of the moist material,

    ventilating the device with sterile gas,

    setting the temperature of the stand plates (2) and of the heating/cooling plates (4, 4') to the unloading temperature, at need to the ambient temperature, at need closing the vessels (3) and

    removing the vessels (3) or the moist material.

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