Freeze-drying device

Abstract

The invention relates to a freeze-drying device having: an evaporation chamber that is mounted so as to be rotated on a shaft (30); a condensation chamber (10) in communication with the evaporation chamber, a product inlet and a product outlet (1, 8) which are connected to the evaporation chamber (5) by first flexible connectors, the product inlet and the product outlet (1, 8) being fixedly mounted relative to the evaporation chamber, and a motor (12) which drives the shaft (30) back and forth on itself, the condensation chamber (10) being fixedly mounted relative to the evaporation chamber (5), the evaporation chamber (5) and the condensation chamber (10) being connected by second flexible connectors.

Description

[0001] TITLE OF THE INVENTION: FREEZE-DRYING DEVICE

[0002] TECHNICAL FIELD

[0003] The invention relates to the field of devices for treating products by freeze-drying. The invention relates more particularly to devices for carrying out bulk freeze-drying.

[0004] The invention finds a particularly advantageous application in the fields of pharmaceutical preparation and food preparation and, more generally, for all high value-added industries which require a freeze-drying preservation process. For example, the invention can be implemented in the field of biotechnology for the production of inoculum for the fermentation of biomass, in the food field for the freeze-drying of fruits, vegetables, beverages and food preparations, in the health field for the freeze-drying of proteins, peptides, enzymes, bacteria, viruses, living cells, sensitive formulations based on antibodies or sensitive molecules, plasma fraction or sensitive polymer formulations.

[0005] PREVIOUS ART

[0006] Freeze-drying is a low-temperature dehydration process that involves removing most of the water contained in a product by sublimation. Freeze-drying produces high-quality end products without damaging the structure and while retaining a large part of the activity of microorganisms or cells. Freeze-dried products have a long-term shelf life due to the lowering of the product's water activity.

[0007] Indeed, by lowering the water activity in the product, no living organisms can develop and all the chemical reactions that take place in water cannot occur. The very low water activity also blocks any microbiological development activity. Thus, the shape and appearance of freeze-dried products are well preserved and their aromatic qualities are much superior to those of products dried by spray drying, fluidized bed or simple drying by multi-effect evaporator processes.

[0008] In addition, the transition of products from frozen to dehydrated, in the absence of a high proportion of liquid water, reduces the possibilities of developing spoilage reactions. Another major technological advantage of freeze-drying is the ability of freeze-dried products to rehydrate quickly thanks to the microscopic pores formed by ice on their surface at the time of freezing.

[0009] The use of freeze-drying, however, is limited by its cost and remains much lower than the use of other drying processes. The low productivity in freeze-drying is due to the discontinuous vacuum operating mode, which results in long processing times ranging from ten hours to several days. Investment and operating costs are also high. For example, the energy consumption of a freeze-drying device is typically in the order of 1,500 to 2,500 kWh per ton of water to be removed.

[0010] As a result, freeze-drying is only applicable for products with high added value. In the food industry, examples include coffee, herbs and spices, ready meals, or ingredients sensitive to heat dehydration (vegetables, fruits, seafood, etc.). For instant dehydrated soups, culinary preparations, and breakfast cereals, processes based on atomization or fluidized beds are commonly used because they are significantly less expensive. The pharmaceutical (vaccines, serum, drugs) and bio-industry (sourdough) sectors are much more strongly concerned by freeze-drying processes, which are the only processes that allow preservation of an active ingredient (biological and / or medicinal activity) in a product stored at room temperature.

[0011] Freeze-drying requires the use of a device comprising an evaporation chamber, incorporating heating means, configured to sublimate the water contained in frozen products, and a condensation chamber connected to the evaporation chamber. The condensation chamber incorporates an ice trap to collect the water vapor from the evaporation chamber. To do this, cooling means are placed in the condensation chamber to cool the ice trap. The chambers are also evacuated by a vacuum pump so as to pass the triple point of water and allow the passage of water from the solid phase to the gaseous phase.

[0012] The freeze-drying process involves a first step of freezing the products in the evaporation chamber or before the products are introduced into this chamber. Rapid freezing is sought so as to form small ice crystals. Indeed, freezing too slowly has the effect of promoting the formation of large crystals likely to damage the structure of the product by tearing its cell walls, for example for yeasts, viruses and animal or plant cells. A second step involves creating a vacuum in the evaporation chamber, the low pressure, generally well below 1 hPa, allowing water in the form of ice to transform into vapor without thawing the products. To do this, the products receive a heat input to provide the energy necessary for the latent heat of sublimation of ice into vapor.The steam enters the conditioned condensation chamber to transform the water vapor into ice by using the ice trap maintained at low temperature, for example -60°C.

[0013] This freeze-drying process allows up to 95% of the water contained in products to be extracted. Freeze-drying can reduce the moisture content of the product to an extremely low level, between 1% and 10% of the product's density, and prevent bacteria and mold from proliferating and enzymes from triggering chemical reactions that could deteriorate the product. As a result, freeze-dried products have a very long shelf life. In airtight packaging, protected from moisture, light, and oxygen, freeze-dried products can be stored at room temperature for many years.

[0014] Bulk freeze-drying is primarily used in the industrial sector, particularly in the food industry, as it allows for the processing of large quantities of products over limited periods of time. Bulk freeze-drying allows for an average freeze-drying time of between five and fifty hours. Reducing freeze-drying time reduces energy consumption, production time, and therefore production costs. In addition, limiting freeze-drying time reduces the product's exposure to heat. This improves the quality of the freeze-dried product.

[0015] However, bulk freeze-drying requires the products to be introduced into the freeze-dryer in a jumble. However, there is a risk of the products clumping together, which could deteriorate the quality of the freeze-dried products.

[0016] To solve this problem, it is possible to set the freeze dryer in motion during the freeze-drying process. The rotating movements thus prevent the products from clumping in the evaporation chamber during freeze-drying while limiting the freeze-drying process time.

[0017] To this end, document WO 82 / 02246 describes a freeze-drying device formed from a cylinder having two concentric parts: respectively a central compartment acting as an evaporation chamber and a peripheral compartment acting as a condensation chamber. The two concentric chambers are installed around a rotation axis allowing a rotational movement to be carried out during freeze-drying to avoid agglomeration of the products.

[0018] However, this document requires opening the chambers to introduce and extract the products before and after freeze-drying. This opening is complex to implement when it is also necessary to ensure that vacuum is applied to the chambers during freeze-drying.

[0019] To address this problem, WO 2017 / 178740 proposes using an evaporation chamber mounted on a controlled rotation axis to perform a reciprocating movement with a small rotation angle, between -90 and 90°. To avoid having to open the evaporation chamber before and after freeze-drying, it is connected to a product inlet and outlet that are fixed relative to the evaporation chamber. The product inlet and outlet are connected by flexible connectors to the evaporation chamber so that the small reciprocating movements cause deformation of the flexible connectors around the evaporation chamber without breaking the connection between the evaporation chamber and the product inlet and outlet.

[0020] However, in all existing freeze-drying devices, the condensation chamber is placed as close as possible to the evaporation chamber, so that the steam extracted from the products to be freeze-dried is very quickly captured and stored in the condensation chamber. The immediate proximity of the two chambers prevents the steam from condensing along the walls of the evaporation chamber and risking falling back into the products.

[0021] For freeze-drying devices using a rotational movement, as described in WO 82 / 02246 and WO 2017 / 178740, the evaporation chamber and the condensation chamber are both set in motion on the same rotational axis. In some embodiments of WO 2017 / 178740, it is even possible to use two condensation chambers. Thus, a powerful motor must be selected to be able to set all the chambers in motion simultaneously. However, these motors consume a lot of energy and are very bulky.

[0022] The technical problem that the invention aims to solve is to set up a freeze-drying device using a rotational movement that consumes less energy and is more compact.

[0023] STATEMENT OF THE INVENTION

[0024] The present invention aims to solve this problem by separating the condensation chamber from the rotational axis and by making it fixed relative to the evaporation chamber. Only the evaporation chamber is then set in motion by the motor, which makes it possible to select a less powerful motor, therefore less energy-consuming and more compact. In addition, the fixed condensation chamber is connected to the moving evaporation chamber by flexible connectors, called "second flexible connectors", which are capable of moving and deforming to absorb the movements of the evaporation chamber relative to the condensation chamber.

[0025] Surprisingly, even if the use of second flexible connectors increases the distance between the evaporation chamber and the condensation chamber, it has been found that the steam generated by the evaporation chamber does not condense on the walls of the evaporation chamber or the hoses and does not fall back into the products being freeze-dried if the hoses are correctly sized, i.e. if the type and number of hoses allows all the steam produced to be extracted according to the pressure and temperature parameters of the chambers. The quality of the freeze-dried products therefore remains unchanged. Thus, contrary to the constant teaching of the state of the art, it is not necessary to place the condensation chamber directly near the evaporation chamber.

[0026] To this end, the invention relates to a freeze-drying device comprising:

[0027] - an evaporation chamber comprising means for heating said evaporation chamber configured to carry out sublimation of the solvent contained in the frozen products intended to be placed in said evaporation chamber, said evaporation chamber being mounted to move in rotation around an axis;

[0028] - at least one condensation chamber communicating with said evaporation chamber, and comprising means for cooling said condensation chamber configured to transform the vapor coming from said evaporation chamber into ice;

[0029] - a product inlet and outlet connected to said evaporation chamber by first flexible connectors, the product inlets and outlets being mounted fixed relative to the evaporation chamber, and

[0030] - a motor driving said axis on itself according to the following back and forth movement:

[0031] - a first movement driving said axis in a first direction of rotation with an angle of rotation between 5° and 90°; and

[0032] - a second movement driving said axis in a second direction of rotation, opposite to the first angle of rotation, with an angle of rotation between -5° and -90°.

[0033] The invention is characterized in that the at least one condensation chamber is fixedly mounted relative to said evaporation chamber, said evaporation chamber and said at least one condensation chamber being connected by second flexible connectors. In certain embodiments, the device comprises at least two condensation chambers. A steam collector provided with means for controlling the steam flow rate can then be arranged between the evaporation chamber and the condensation chambers. The steam collector thus receives the steam from the evaporation chamber and controls the steam flow rate sent to each condensation chamber according to the trapping capacity of said condensation chamber.

[0034] According to the invention, the trapping capacity corresponds to the flow rate of vapor that can be condensed by the condensation chamber in a predetermined time interval. In practice, this trapping capacity can change over time. For example, the vapor can be condensed by an ice trap in the form of a coiled tube in which a heat transfer fluid, for example liquid nitrogen, circulates.

[0035] When steam comes into contact with the ice trap, it solidifies on the trap wall. This causes ice to build up in layers on the trap walls. The thicker this layer of ice, the less effective the trap becomes. The trapping capacity of the condensation chamber then decreases, and it may be useful to send the steam to another trap via the steam collector while waiting for the trap to regenerate and regain sufficient performance.

[0036] In practice, in order to limit energy losses linked to the passage through the second flexible connectors connecting the condensation chamber to the evaporation chamber, it is possible to determine the optimal number of flexible connectors. This determination of the number of flexible connectors depends on several parameters such as the pressure and temperature of the evaporation and condensation chambers, the desired flow rate for processing the products to be freeze-dried, and the diameter and length of the flexible connectors available.

[0037] In practice, when all other parameters are fixed, the number N of flexible connectors is proportional to the vaporization flow rate of the evaporation chamber 5. When it is desired to evaporate a solvent with an evaporation flow rate, and the evaporation and condensation chambers have the following parameters:

[0038] - the evaporation chamber has an operating temperature between -30°C and -20°C, a pressure between 200 and 600 pbars, and

[0039] - the condensation chamber has an operating temperature between -100 and - 50°C, a pressure between 40 and 200 pbars.

[0040] Then, the second flexible connectors are selected with:

[0041] - a diameter between 0.08 and 0.12 m, - a length between 2 and 10 m, and

[0042] - a number of hoses proportional to the evaporation flow rate, with a proportionality coefficient between 0.7 and 1.

[0043] There are different embodiments in which parameters can be set, depending on constraints related to the operation of certain products to be lyophilized for example. Typically, the nature of the solvent may require specific pressure and temperature ranges to carry out lyophilization.

[0044] According to a first embodiment, when it is desired to evaporate an aqueous solvent with an evaporation rate of between 10 and 11 kg / h, and the evaporation and condensation chambers have the following parameters:

[0045] - the evaporation chamber has an operating temperature between -30°C and -20°C, a pressure between 400 and 580 pbars, and

[0046] - the condensation chamber has an operating temperature set at -60°C, a pressure set at 100 pbars.

[0047] Then, the second flexible connectors are selected with:

[0048] - a diameter between 0.1 and 0.105 m,

[0049] - a length between 3 and 4.5 m, and

[0050] - a number of hoses between 7 and 13.

[0051] According to a second embodiment, when it is desired to evaporate an aqueous solvent with an evaporation rate of between 9 and 11 kg / h, and the evaporation and condensation chambers have the following parameters:

[0052] - the evaporation chamber has an operating temperature of -20°C, a pressure of 600 pbars, and

[0053] - the condensation chamber has an operating temperature between -100 and -50°C, a pressure between 100 and 200 pbars.

[0054] Then, the second flexible connectors are selected with:

[0055] - a diameter fixed at 0.08 m,

[0056] - a length fixed at 3 m, and

[0057] - a number of hoses between 11 and 13.

[0058] According to a third embodiment when it is desired to evaporate an aqueous solvent with an evaporation flow rate set at 9 kg / h, and the evaporation and condensation chambers have the following parameters:

[0059] - the evaporation chamber has an operating temperature of -30°C, a pressure of 600 pbars, and

[0060] - the condensation chamber has an operating temperature set at -60°C, a pressure between 100 and 200 pbars.

[0061] Then, the second flexible connectors are selected with:

[0062] - a diameter fixed at 0.08 m,

[0063] - a length between 3 and 7 m, and

[0064] - a number of hoses between 10 and 15.

[0065] According to a fourth embodiment, when it is desired to evaporate an aqueous solvent with an evaporation flow rate set at 10 kg / h, and the evaporation and condensation chambers have the following parameters:

[0066] - the evaporation chamber has an operating temperature of -20°C, a pressure between 200 and 250 pbars, and

[0067] - the condensation chamber has an operating temperature set at -60°C, a pressure set at 100 pbars.

[0068] Then, the second flexible connectors are selected with:

[0069] - a diameter fixed at 0.12 m,

[0070] - a length between 2 and 3 m, and

[0071] - a number of hoses between 11 and 18.

[0072] According to a fifth embodiment, when it is desired to evaporate an aqueous solvent with an evaporation flow rate set at 11 kg / h, and the evaporation and condensation chambers have the following parameters:

[0073] - the evaporation chamber has an operating temperature between -30°C and -10°C, a pressure between 400 and 550 pbars, and

[0074] - the condensation chamber has an operating temperature set at -70°C, a pressure set at 100 pbars.

[0075] Then, the second flexible connectors are selected with:

[0076] - a diameter fixed at 0.1 m,

[0077] - a length fixed at 4 m, and

[0078] - a number of hoses between 9 and 13.

[0079] According to a sixth embodiment, when it is desired to evaporate an organic solvent having an apparent molar mass of between 0.02 and 0.025 kg / mol, with an evaporation flow rate of 10 kg / h, and the evaporation and condensation chambers have the following parameters:

[0080] - the evaporation chamber has an operating temperature set at -15°C, a pressure set at 300 pbars, and

[0081] - the condensation chamber has an operating temperature set at -70°C, a pressure set at 100 pbars.

[0082] Then, the second flexible connectors are selected with:

[0083] - a diameter fixed at 0.12 m,

[0084] - a length between 5 and 8 m, and

[0085] - a number of hoses between 9 and 14.

[0086] According to a seventh embodiment, when it is desired to evaporate an organic solvent having an apparent molar mass fixed at 0.025 kg / mol, with an evaporation flow rate of 10 kg / h, and the evaporation and condensation chambers have the following parameters:

[0087] - the evaporation chamber has an operating temperature between -30°C and -20°C, a pressure set at 300 pbars, and

[0088] - the condensation chamber has an operating temperature between -90 and -70°C, a pressure between 50 and 100 pbars.

[0089] Then, the second flexible connectors are selected with:

[0090] - a diameter fixed at 0.1 m,

[0091] - a length between 7 and 10 m, and

[0092] - a number of hoses between 18 and 24.

[0093] SUMMARY DESCRIPTION OF THE FIGURES

[0094] The manner of carrying out the invention, as well as the advantages which result from it, will emerge clearly from the description of the embodiment which follows, supported by the appended figures in which:

[0095] [Fig.l] Figure 1 is a schematic structural representation of a freeze-drying device according to a first embodiment of the invention;

[0096] [Fig.2] Figure 2 is a schematic structural representation of a freeze-drying device according to a second embodiment of the invention;

[0097] [Fig.3] Figure 3 is a sectional view of the position of a partition relative to the evaporation chamber in a first position of the freeze-drying device of Figure 1;

[0098] [Fig.4] Figure 4 is a sectional view of the position of a partition relative to the evaporation chamber in a second position of the freeze-drying device of Figure 1; and [Fig.5] Figure 5 is a sectional view of the position of a partition relative to the evaporation chamber in a third position of the freeze-drying device of Figure 1.

[0099] DETAILED DESCRIPTION OF THE INVENTION

[0100] Figure 1 illustrates a freeze-drying device comprising an evaporation chamber 5 and a condensation chamber 10. An inlet 1 in the form of a hopper is connected to the evaporation chamber 5 via a first flexible connector 42. The hopper is further equipped with a first lock 2 so as to introduce products to be freeze-dried when the lock 2 is open. An outlet 8 in the form of a hopper is also connected to the evaporation chamber 5 via a flexible connector. The hopper is further equipped with a second lock 9 so as to extract the freeze-dried products when the lock 9 is open. The locks 2 and 9 also make it possible to guarantee the sealing and sterility of the chambers 5, 10. For example, locks 2, 9 of the brand "

[0101] Agilent Technologies" or "Gericke" can be used. Alternatively, the invention can be implemented with a single inlet / outlet performing both product introduction and extraction functions.

[0102] The evaporation chamber 5 has a double external wall in which a heat transfer fluid circulates to heat the evaporation chamber 5. Preferably, the internal surface of the evaporation chamber 5 is mirror polished so as to promote the sliding of the load and minimize the angle of slope.

[0103] The heat transfer fluid is heated by an external device connected to the double wall by a fluid inlet 15 and a fluid outlet 16. A steam inlet 31 is also connected to the evaporation chamber 5 in order to sterilize the evaporation chamber 5.

[0104] These heating means 15, 16 allow sublimation of the frozen products placed in the evaporation chamber. Alternatively, the heat transfer fluid can be heated by a heat exchanger coupled to an external heat source. Preferably, the heating can be provided by an electric heating jacket powered via flexible electric cables. The heating jacket is made of silicone and a heating resistor allows the electrical energy to be converted into heat. This heating system is advantageous since the electric cables are more flexible and therefore more resistant to the shear stresses linked to the back and forth movements of the evaporation chamber compared to piping transporting a heat transfer fluid. The products can be introduced in a frozen form through the inlet 1. Alternatively, the products can be frozen directly in the evaporation chamber 5.In this embodiment, the products are introduced at room temperature and the heat transfer fluid circulating in the outer double wall is refrigerated to a very low temperature, for example of the order of -60°C, so as to cause the freezing of the products before the evaporation step. Freezing can also be carried out in inlet 1. For example, freezing can be obtained directly in pellets by means of a drop falling into a stream of nitrogen.

[0105] The condensation chamber 10 is connected to the evaporation chamber 5 via second flexible connectors 41. Alternatively, several condensation chambers 10 may be connected to the evaporation chamber 5 via the second flexible connectors 41. In some embodiments, the second flexible connectors 41 are connected to the condensation chamber via a steam collector not shown in the figures. The second flexible connectors 41 supply the steam collector via a steam inlet. The steam collector has several steam outlets connected to different inlets distributed regularly along the condensation chamber 10. The latter is then supplied by several inlet flows, which makes it possible to better distribute the steam in the chamber and to avoid condensation.

[0106] The passage of steam through the second flexible connectors 41, between the evaporation chamber 5 and the condensation chamber 10 is controlled via an airlock 4. The airlock 4 may comprise a grid or a filter allowing the steam to pass through and retaining particles of the product that may be entrained by the water vapor. Preferably, the filter is made of Gore-Tex®, a registered trademark.

[0107] The condensation chamber 10 comprises an ice trap 11 in the form of a coiled tube in which a heat transfer fluid, for example liquid nitrogen, circulates. The heat transfer fluid is produced by an external device and is conducted into the pipe via an inlet 17 to an outlet 18. Alternatively, the heat transfer fluid may be cooled by a heat exchanger coupled to an external cold source.

[0108] The cooling means 17, 18 are implemented when the airlock 4 is open and the steam enters the condensation chamber. The steam then freezes on the tube of the ice trap 11. The number of turns and the section of the tube forming the ice trap 11 are determined according to the quantity of steam to be recovered.

[0109] A steam inlet 32 ​​is also connected to the condensation chamber 10 in order to sterilize the condensation 10 and evaporation chambers prior to starting the freeze-drying process itself. To do this, in a step prior to freeze-drying, the airlock 4 is opened and steam is introduced into the two chambers 5, 10. During the process itself, the steam injected by the steam injection nozzle 32 causes the ice present on the ice trap 11 to melt. A purge 33 thus extracts the injected steam to evaporate the ice contained in the condensation chamber 10 as well as the steam generated for sterilization.

[0110] The condensation chamber 10 is also connected to a vacuum pump 6 via a pipe provided with a valve 7. This vacuum pump 6 is configured to create a vacuum in the condensation chamber 10 and the evaporation chamber 5 when the airlock 4 is open. When the vacuum is created in these two chambers, the valve 7 is kept open and the vacuum is maintained by the condensation of the vapor on the ice trap 11. For example, the vacuum values ​​are between 10 pbar and 600 pbar.

[0111] The evaporation chamber 5 is mounted integral with a rotation axis 30, while the condensation chamber 10 is mounted fixed relative to the evaporation chamber 5. Preferably, the evaporation chamber 5 is cylindrical and the axis 30 passes through the center of the two flat faces of the cylinder so as to uniformly distribute the mass of the evaporation chamber 5 around the axis 30. The axis 30 is driven in rotation by a motor 12.

[0112] According to the invention, two opposite rotational movements of the evaporation chamber are induced by the axis 30 driven by the motor 12 and are limited in amplitude so as to create a back and forth movement.

[0113] Figures 3 to 5 illustrate the positions of the axis 30 during this back and forth movement. In a first position, illustrated in Figure 3, the axis 30 is not driven in rotation by the motor 12. A first movement of the motor 12, illustrated in Figure 4, drives the axis 30 on itself and consequently the evaporation chamber 5 in a first direction of rotation with an angular displacement al less than 180°.

[0114] A second movement of the motor 12, illustrated in Figure 5, drives the axis 30 on itself and consequently the evaporation and condensation chambers in a second direction of rotation, opposite to the first direction of rotation, with an angular displacement a2 substantially equal to the angular displacement of the first movement. The back and forth movement thus corresponds to a swinging of the axis 30, that is to say a rotation of the axis 30 on itself in one direction then in the other. The axis 30 therefore does not perform a complete rotation, thus limiting the risk of winding of the flexible connectors connecting the external devices of the evaporation chamber 5. On the contrary, the flexible connectors are configured to deform and absorb the movements of the evaporation chamber 5 during rotations so as to maintain a sealed and sterile connection.

[0115] The rotational movements thus make it possible to avoid the agglomeration of the products in the evaporation chamber 5 during freeze-drying while limiting the time of the freeze-drying process. Advantageously, the evaporation chamber 5 also comprises baffles arranged inside the evaporation chamber 5.

[0116] The baffles extend radially towards the inside of the evaporation chamber 5 and allow for improved mixing of the products during freeze-drying. For example, ploughshares of the “Palamatic®” brand can be used.

[0117] The axis 30 can be mounted horizontally relative to the cylindrical body of the evaporation chamber 5. In this embodiment, the device advantageously comprises means for pivoting the axis in the vertical plane making it possible to guide the products placed in the evaporation chamber 5 towards the outlet 8 when the freeze-drying time is reached.

[0118] Alternatively, the shaft 30 may be mounted at an angle, i.e. inclined in the vertical plane so as to guide the products towards the outlet 8 throughout the freeze-drying process. In this embodiment, the outlet 8 is lower than the inlet 1 so as to use gravity to move the freeze-dried products towards the outlet 8.

[0119] Thus, to meet the rotation constraints of the evaporation chamber 5, the flexible connectors 41, 42 have the function of connecting a fixed element to a mobile element, such as the evaporation chamber 5.

[0120] In this case, the inlet 1 and outlet 8 hoppers are connected to the evaporation chamber 5 by sterile flexible sleeves. Advantageously, the heating and cooling means of the two chambers 5, 10 as well as the vacuum pump 6 are also connected to the respective chambers by first flexible connectors 42. Preferably, the first flexible connectors 42 are made of stainless steel to meet sterility constraints. The first flexible connectors 42 advantageously have turns so as to limit the work hardening of the stainless steel. Alternatively, other materials can be used without changing the invention. The first flexible connectors 42 make it possible to guarantee the connection of these elements with the evaporation chamber 5, even when the latter is rotated on itself by the motor 12.Depending on the embodiments, the fixed condensation chamber 10 can also be connected to the discharge hoppers by flexible connectors or, on the contrary, be connected to the discharge hoppers by any other type of connector, since it does not have the same rotation constraints. The bending capacity of the first flexible connectors 42 makes it possible to absorb the movements of the evaporation chamber 5 relative to the external elements. The length of the connectors is also chosen to ensure that the connection is maintained during rotation of the evaporation chamber 5. For example, flexible connectors of the brand “Stâubli®” or “GECITECH®” can be used.

[0121] Furthermore, the condensation chamber 10 is also connected to the evaporation chamber by second flexible connectors 41.

[0122] Preferably, the second flexible connectors 41 are made of stainless steel or reinforced polyvinyl chloride (PVC) to meet temperature and sterility constraints. The second flexible connectors 41 advantageously have turns so as to limit work hardening. Alternatively, other materials may be used without changing the invention. The bending capacity of the second flexible connectors 41 makes it possible to absorb the movements of the evaporation chamber 5 relative to the condensation chamber 10. The length L of the second flexible connectors 41 is also chosen to ensure that the connection is maintained during rotation of the evaporation chamber 5.

[0123] Furthermore, since the freeze-drying process is particularly dependent on temperature and pressure differences, the chambers 5, 10 are preferably instrumented by temperature sensors 20, 24 and pressure sensors 21.

[0124] Two sensors 20, 21 are arranged in the evaporation chamber 5 to monitor the temperature and pressure in the evaporation chamber 5. A third sensor 24 is arranged in the condensation chamber 10 to monitor the temperature of the condensation chamber 10. As a result, an operator can monitor the freeze-drying process by means of the sensors 20, 21, 24 and estimate the amount of water removed from the products over time. It is thus possible to determine the precise moment at which a desired water concentration is reached to stop freeze-drying.

[0125] In practice, it is currently not possible to find on the market a single second flexible connector 41 with a diameter sufficient to properly evacuate the steam. The existing second flexible connectors 41 have either limited maximum sizes or excessive rigidity. A compromise between a sufficiently small radius of curvature to limit the size and a sufficiently large diameter can, however, be determined in order to limit the number of hoses. In practice, to determine the number N, the diameter D and the length L of the second flexible connectors 41, those skilled in the art can apply the laws of fluid mechanics. The number N, the diameter D and the length L of the second flexible connectors 41 is in particular conditioned by the pressure conditions Pl, P2 and temperature Tl, T2 prevailing in the chambers 5 and 10 and measured by the sensors 20, 21, 24.

[0126] In particular, by fixing the other parameters, the number N of second flexible connectors 41 can be defined with a coefficient of proportionality with the evaporation flow rate of the steam contained in the evaporation chamber 5. The coefficient of proportionality between the number N of second flexible connectors 41 and the evaporation flow rate depends on the length L and is for example between 0.7 and 1.

[0127] There are different embodiments in which some of these parameters can be fixed, depending on constraints linked to the exploitation of certain products to be lyophilized for example. Typically, the nature of the solvent may require particular pressure and temperature ranges to carry out lyophilization.

[0128] According to a first example of embodiment, it is sought to evaporate an aqueous solvent with an evaporation rate of between 10 and 11 kg / h.

[0129] When the condensation chamber has an operating temperature T2 set at -60°C and a pressure P2 set at 100 pbars, then the evaporation chamber has an operating temperature Tl varying between -30°C and -20°C, a pressure PI varying between 400 and 580 pbars.

[0130] The second flexible connectors 41 are then selected with:

[0131] - a diameter D between 0.1 and 0.105 m,

[0132] - a length L between 3 and 4.5 m, and

[0133] - a number N of hoses between 7 and 13.

[0134] According to a second exemplary embodiment, it is sought to evaporate an organic solvent having an apparent molar mass of between 0.02 and 0.025 kg / mol, with an evaporation rate of 10 kg / h.

[0135] When the evaporation chamber 5 has an operating temperature T1 set at -15°C and a pressure PI set at 300 pbars, and the condensation chamber 10 has an operating temperature T2 set at -70°C and a pressure P2 set at 100 pbars, then the second flexible connectors 41 are selected with:

[0136] - a diameter D fixed at 0.12 m,

[0137] - a length L between 5 and 8 m, and

[0138] - a number of flexible hoses N between 9 and 14.

[0139] The freeze-drying device may also comprise several condensation chambers. As illustrated in FIG. 2, the freeze-drying device may, for example, comprise two condensation chambers 10A and 10B. In order to distribute the vapor from the evaporation chamber 5 between the two condensation chambers 10A and 10B, a vapor collector 43 may be added.

[0140] The steam collector 43 is positioned at the outlet of the second flexible connectors 41 and is connected to the condensation chambers 10A and 10B by connectors 44A, 44B. The number, length and diameter of the connectors 44A, 44B can be chosen according to the dimensions of the condensation chamber 10A, 10B considered.

[0141] The steam collector 43 is mounted fixed relative to the evaporation chamber 5. The steam collector 43 and the condensation chambers 10A and 10B being fixed relative to each other, the connectors 44A, 44B can be rigid or flexible pipes without changing the invention.

[0142] Control means allow the steam flow rate sent to one or other of the condensation chambers 10A, 10B to be modified. The control means can be controlled manually or automatically by positioning, for example, a sensor within each condensation chamber 10A, 10B. The sensor can thus measure the trapping capacity of the chamber and, depending on the value of this measurement, the steam flow rate sent to the chamber is adapted to allow the trap to regenerate.

[0143] For example, when the condensation chambers 10A, 10B comprise an ice trap 11A, 11B, the sensor can measure the thickness of the layer of ice accumulated around the trap 11A, 11B. If this layer of ice is thicker than a predetermined threshold, the flow rate of steam reaching the trap 11A, 11B can be reduced to allow time for the trap to regenerate by reducing the thickness of the layer of ice. During this time, the flow rate of steam reaching the other trap 11A, 11B can be increased to compensate for the decrease on the other trap and thus maintain a constant overall treatment flow rate.

[0144] In conclusion, the invention makes it possible to develop a freeze-drying device that consumes less energy and is more compact.

Claims

DEMANDS 1. Lyophilization device comprising: - an evaporation chamber (5) comprising heating means (15, 16) of said evaporation chamber (5) configured to effect a sublimation of the solvent contained in the frozen products intended to be placed in said evaporation chamber (5), said evaporation chamber (5) being mounted to rotate about an axis (30); - at least one condensation chamber (10) communicating with said evaporation chamber (5), and comprising cooling means (17, 18) for said condensation chamber (10) configured to transform the vapor from said evaporation chamber (5) into ice; - a product inlet and outlet (1, 8) connected to said evaporation chamber (5) by first flexible connectors (42), the product inlet and outlet (1, 8) being fixedly mounted relative to the evaporation chamber (5), and - a motor (12) driving said shaft (30) on itself according to the following back-and-forth movement: - a first movement causing said axis (30) to rotate in a first direction with an angle of rotation (al) between 5° and 90°; and - a second movement driving said axis (30) in a second direction of rotation, opposite to the first angle of rotation, with an angle of rotation (a2) between -5° and -90°; characterized in that said at least one condensation chamber (10) is mounted fixed relative to said evaporation chamber (5), said evaporation chamber (5) and said at least one condensation chamber (10) being connected by second flexible connectors (41).

2. A freeze-drying device according to claim 1, wherein the device comprises at least two condensation chambers (10) and a steam collector (43) equipped with steam flow control means, the steam collector (43) being disposed between the evaporation chamber (5) and the condensation chambers (10), the steam collector (43) receiving the steam from the evaporation chamber and controlling the steam flow sent to each condensation chamber Lyophilization device according to claim 1, wherein the aim is to evaporate a solvent having an evaporation rate, and the evaporation chambers (5) and condensation chambers (10) have the following parameters: - the evaporation chamber (5) has an operating temperature (Tl) between -30°C and -20°C, a pressure (PI) between 200 and 600 pbars, - The condensation chamber (10) has an operating temperature (T2) between -100 and -50°C, a pressure (P2) between 40 and 200 pbar, the second flexible connectors (41) are selected with: - a diameter (D) between 0.08 and 0.12 m, - a length (L) between 2 and 10 m, and - a number of flexible hoses (N) proportional to the evaporation rate, with a proportionality coefficient between 0.7 and 1. Freeze-drying device according to claim 1 or 2, wherein the aim is to evaporate an aqueous solvent with an evaporation rate between 10 and 11 kg / h, and the evaporation (5) and condensation (10) chambers have the following parameters: - the evaporation chamber (5) has an operating temperature (Tl) between -30°C and -20°C, a pressure (PI) between 400 and 580 pbars, - The condensation chamber (10) has a set operating temperature (T2) of -60°C, a pressure (P2) fixed at 100 pbars, and the second flexible connectors (41) are selected with: - a diameter (D) between 0.1 and 0.105 m, - a length (L) between 3 and 4.5 m, and - a number of hoses (N) between 7 and 13. Freeze-drying device according to claim 1 or 2, wherein the aim is to evaporate an aqueous solvent with an evaporation rate between 9 and 11 kg / h, and the evaporation (5) and condensation (10) chambers have the following parameters: - the evaporation chamber (5) has an operating temperature (Tl) of -20°C, a pressure (PI) of 600 pbars, - the condensation chamber (10) has an operating temperature (T2) between -100 and -50°C, a pressure (P2) between 100 and 200 pbars, the second flexible connectors (41) are selected with - a diameter (D) fixed at 0.08 m, - a length (L) fixed at 3 m, and - a number of flexible hoses (N) between 11 and 13.

6. Lyophilization device according to claim 1 or 2, wherein the aim is to evaporate an aqueous solvent with an evaporation rate fixed at 9 kg / h, and the evaporation (5) and condensation (10) chambers have the following parameters: - the evaporation chamber (5) has an operating temperature (Tl) of - 30°C, a pressure (PI) of 600 pbars, - The condensation chamber (10) has an operating temperature (T2) set at -60°C, a pressure (P2) between 100 and 200 pbar, the second flexible connectors (41) are selected with: - a diameter (D) fixed at 0.08 m, - a length (L) between 3 and 7 m, and - a number of flexible hoses (N) between 10 and 15.

7. Lyophilization device according to claim 1 or 2, wherein the aim is to evaporate an aqueous solvent with an evaporation rate fixed at 10 kg / h, and the evaporation (5) and condensation (10) chambers have the following parameters: - the evaporation chamber (5) has an operating temperature (Tl) of -20°C, a pressure (PI) between 200 and 250 pbars, - The condensation chamber (10) has an operating temperature (T2) set at -60°C, a pressure (P2) set at 100 pbars, the second flexible connectors (41) are selected with: - a diameter (D) fixed at 0.12 m, - a length (L) between 2 and 3 m, and - a number of hoses (N) between 11 and 18. . Freeze-drying device according to claim 1 or 2, wherein the aim is to evaporate an aqueous solvent with an evaporation rate fixed at 11 kg / h, and the evaporation (5) and condensation (10) chambers have the following parameters: - the evaporation chamber (5) has an operating temperature (Tl) between -30°C and -10°C, a pressure (PI) between 400 and 550 pbars, - The condensation chamber (10) has an operating temperature (T2) set at -70°C, a pressure (P2) set at 100 pbars, and the second flexible connectors (41) are selected with: - a diameter (D) fixed at 0.1 m, - a length (L) fixed at 4 m, and - a number of flexible hoses (N) between 9 and 13. Freeze-drying device according to claim 1 or 2, wherein the aim is to evaporate an organic solvent having an apparent molar mass between 0.02 and 0.025 kg / mol, with an evaporation rate of 10 kg / h, and the evaporation (5) and condensation (10) chambers have the following parameters: - the evaporation chamber (5) has an operating temperature (Tl) fixed at -15°C, a pressure (PI) fixed at 300 pbars, - The condensation chamber (10) has an operating temperature (T2) set at -70°C, a pressure (P2) set at 100 pbars, and the second flexible connectors (41) are selected with: - a diameter (D) fixed at 0.12 m, - a length (L) between 5 and 8 m, and - a number of flexible hoses (N) between 9 and 14. Lyophilization device according to claim 1 or 2, wherein the aim is to evaporate an organic solvent having an apparent molar mass fixed at 0.025 kg / mol, with an evaporation rate of 10 kg / h, and the evaporation chambers (5) and condensation chambers (10) have the following parameters: - the evaporation chamber (5) has an operating temperature (Tl) between -30°C and -20°C, and a pressure (PI) fixed at 300 pbars, - The condensation chamber (10) has an operating temperature (T2) between -90 and -70°C, a pressure (P2) between 50 and 100 pbars, the second flexible connectors (41) are selected with: - a diameter (D) fixed at 0.1 m, - a length (L) between 7 and 10 m, and - a number of flexible hoses (N) between 18 and 24.

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