EP3926277A1

EP3926277A1 - Plate freezer

Info

Publication number: EP3926277A1
Application number: EP20181117.1A
Authority: EP
Inventors: Johannes KIRCHMAIR
Original assignee: Single Use Support GmbH
Current assignee: Single Use Support GmbH
Priority date: 2020-06-19
Filing date: 2020-06-19
Publication date: 2021-12-22

Abstract

Plate freezer, in particular for freezing and/or thawing biopharmaceutical fluids, comprising
- a device frame (2),
- a plurality of cooling plates (3) mounted on the device frame so as to be movable linearly substantially along a first axis (X1) with respect to the device frame from first relative positions to second relative positions and/or from the second relative positions to the first relative positions and
- a drive train (4) for driving the movement of the cooling plates (3),
wherein first distances present between neighbouring cooling plates (3) in the first relative positions are large enough to admit containers for to be cooled and/or heated goods between the cooling plates (3) and second distances present between neighbouring cooling plates (3) in the second relative positions are smaller than in the first relative positions, and wherein the drive train (4) comprises
- a linear drive device (5), in particular a spindle drive, for creating a linear drive motion substantially along a second axis (X2), which is transversal with respect to the first axis (X1),
- a flexible pulling member (6), in particular a chain, for pulling the cooling plates (3) along the first axis, the flexible pulling member (6) comprising a first end (7) and a second end (8), wherein the first end (7) of the flexible pulling member is attached to the cooling plates (3) and/or a mounting device for the cooling plates (3) and the second end (8) of the flexible pulling member (6) is attached to an output side (9) of the linear drive device (5), and
a, preferably rotatable, guide (10) mounted on the device frame (2) for redirecting the flexible pulling member (6) from an orientation along the first axis (X1) for pulling the cooling plates (3) to an orientation along the second axis (X2) for being pulled by the linear drive device (5).

Description

The present invention relates to plate freezer, in particular for freezing biopharmaceutical liquids, according to the classifying portion of claim 1.
Accordingly, plate freezers according to the invention include

a device frame,
a plurality of cooling plates mounted on the device frame so as to be movable linearly substantially along a first axis with respect to the device frame from first relative positions to second relative positions and/or from the second relative positions to the first relative positions and
a drive train for driving the movement of the cooling plates,

That means the cooling plates are moved closer to the containers before the freezing process is started in order to improve heat transfer between the containers and the cooling plates. Preferably, the plate freezer according to the invention is adapted to establish contact between the containers and every neighbouring cooling plate in order to optimize the heat transfer.
Known in the prior art are plate freezers for freezing foodstuffs such as fish. For example in EP 2902736 A1 , EP 2083234 A2 , or US 4907421 hydraulic cylinders are disclosed for driving the movement of the cooling plates for improving the heat transfer. Although there are of course requirements for maintaining the purity of the products in the food industry, such requirements are naturally much more stringent in the pharmaceutical industry, and in particular the biopharmaceutical industry. For any product in the pharmaceutical industry the contamination with any kind of foreign material down to nanometre scale has to be avoided. Hydraulic cylinders can therefore not be used for such applications.
A freezing device specially adapted for freezing biopharmaceutical liquids is disclosed in WO 2012/135216 A2 . However, this device does not offer mechanized movement of the cooling elements, such that the operation of this device is more complicated - and therefore prone to operator error - than desirable, because there is less space for putting the containers in the corresponding cooling areas in the device.
A first solution which could be contemplated by persons skilled in the art would be to use spindle drives (e.g. at four corners of the cooling plates) instead of hydraulic cylinders as disclosed in EP 2902736 A1 , EP 2083234 A2 , or US 4907421 . However, such solutions require a large space at least in one position of the cooling plates as the spindle of the spindle drive has to be allowed to extend in at least one direction.
Accordingly, the object of the invention is to provide a plate freezer which is easier to use, smaller and/or offers lower risk of contaminating the products to be frozen.
This object is achieved with the features of claim 1, namely in that the drive train comprises

a linear drive device, in particular a spindle drive, for creating a linear drive motion substantially along a second axis, which is transversal with respect to the first axis,
a flexible pulling member, in particular a chain, for pulling the cooling plates along the first axis, the flexible pulling member comprising a first end and a second end, wherein the first end of the flexible pulling member is attached to the cooling plates and/or a mounting device for the cooling plates and the second end of the flexible pulling member is attached to an output side of the linear drive device, and
a, preferably rotatable, guide mounted on the device frame for redirecting the flexible pulling member from an orientation along the first axis for pulling the cooling plates to an orientation along the second axis for being pulled by the linear drive device.

The usage of a flexible pulling member, such as a chain, belt, or cable makes it possible to change the direction of the motion, which the linear drive device generates along the second axis into the direction of the first axis, along which the cooling plates have to be moved. Therefore, the linear drive device can be arranged in a space saving manner, while retaining the easy to operate and high heat transfer properties of the known basic principle of moving cooling plates.
Surprisingly, the usage of a flexible pulling member and some kinematics also make it easier to avoid possible contaminants than for example introducing more or better housings or seals for hydraulic cylinders known from the prior art, in particular if spindle drives are used as linear drive device.
Protected is also the usage of a plate freezer according to the invention for cooling, freezing, heating and/or thawing a biopharmaceutical fluid.
Biopharmaceutical liquids can be understood as any kind of fluid that is generated and/or used before, during and/or after the production of a biopharmaceutical medicine.
The invention can be applied to any plate freezer, in particular if effective heat transfer, ease of use, and a low risk of contamination is important.
Cooling plates can preferably be of rectangular basic shape. However, also other basic shapes, such as disk-like shapes or general polygonal shapes, are in principle conceivable.
Generally, cooling plates include medium channels for a cooling medium supplied by a cooling device. By pumping the cooling medium through the cooling channels the heat from the containers for to be frozen goods can transfer to the cooling medium and thus be taken away from the containers to freeze the goods. As mentioned before, this principle can also be used to merely cool the goods to a desired temperature or to heat and/or thaw the goods.
However, in general also other ways for cooling can be used according to the invention, such as for example using thermoelectric coolers.
A cooling medium used together with the cooling device may be for the main part oil.
Plate freezers can be produced and distributed together with the cooling device for the cooling medium or separately therefrom.
The cooling plates generally extend in directions substantially perpendicular to a third axis and are arranged successively along this third axis. In particularly preferred embodiments the third axis and the first axis are parallel. In some embodiments however, also an angle between the first axis and the third axis can be present. This angle can be less than 15°, preferably less than 10° and particularly preferably less than 5°. The same applies for angles between the third axis and directions in which the cooling plates extend.
The cooling plates can have a thickness between 0.5 cm and 10 cm, and preferably a thickness between 1 cm and 4 cm.
The cooling plates can preferably overlap viewed along the third axis, in particular they can overlap exactly (i.e. no cooling plate "stands out").
Particularly preferably, the cooling plates can be of, in particular exactly, the same size.
The linear movement of the linear drive device along the second axis and/or the movement of the cooling plates along the first axis can be only linear in preferred embodiments. Embodiments of the invention are however also conceivable, where the first axis and/or the second axis can be (preferably only slightly) curved. Additionally or alternatively, rotations can be superimposed on the movements along the first axis and/or the second axis.
It should be mentioned, that in preferred embodiments a relative movement between the cooling plates can only be present when the containers of to be cooled and/or heated goods are arranged between the cooling plates (for an embodiment according to this feature it is referred to the figures and the description of the figures).
As also mentioned before, particularly preferred embodiments of the invention are adapted to establish contact between the containers and every neighbouring cooling plate (in the second relative positions) in order to optimize the heat transfer.
The first axis and the second axis may or may not intersect. The term "transversal" can be understood as the first axis and the second axis being substantially perpendicular in a view along a viewing axis substantially perpendicular to both the first axis and the second axis. The term "substantially perpendicular" can be understood to differ from an exact right angle by less than 45°, preferably less than 20° and particularly preferably less than 5°.
Spindles for spindle drives should be viewed as wear part so that the use of spindles as linear drive devices can also offer a reduction of wear parts in comparison with constructions with spindle drives at all the corners of the cooling plates.
As already mentioned, the first distances are present when the cooling plates are in the first relative positions and the second distances are present when the cooling plates are in the second relative positions. Preferably, the cooling plates are spaced equidistant from each other in the first positions and/or the second positions (i.e. the distances from the first set of distances are equal and the distances from the second set of distances are equal).
Further advantageous embodiments are defined in the dependent claims.
In particularly preferred embodiments, the first axis can be substantially vertical, the flexible pulling member can be arranged to pull the cooling plates substantially upwards, and the second axis can be substantially horizontal. In this way the effect of gravity can be used to return the cooling plates into the first positions when they have been pulled into the second position or vice versa, i.e. the drive train only has to pull with substantial force in one of the directions and in the other direction potentially only friction has to be overcome (as gravity pulls the cooling plates down). At the same time the space saving effect of the invention through a horizontal orientation of the linear drive device can be utilized.
The linear drive device can be arranged above and/or below the cooling plates in such embodiments, the arrangement above the cooling plates being particularly preferred as the cooling plates have to be pulled upwards.
Two or more linear drive devices for creating the linear drive motion substantially along a second axis can be provided. Such multiple drive devices can each have substantially the same function as a single drive device. In the following the expressions "drive device" and "drive devices" may be used interchangeably depending on context.
The output side of the linear drive device, preferably of the two or more linear drive devices, is connected to a bar, to which the flexible pulling member is attached. The bar can have different forms, in particular cross sections. Preferably, the bar can be of straight configuration. However, also embodiments can be conceived, where the bar has curves, for example to accommodate other constructive elements of the plate freezer according to the inventions.
A plurality of flexible pulling members, preferably four flexible pulling members, can be provided, all of which are preferably connected to the bar. In this way, the flexible pulling members can e.g. be attached near the corners of polygon-shaped cooling plates.
In the following the expressions "pulling member" and "pulling members" may be used interchangeably depending on context.
Embodiments of the invention with rectangular-shaped cooling plates, and a bar actuated by the linear drive device, to which four flexible pulling members are attached near the corners of the cooling plates can be particularly preferred, as they may be particularly simple and space saving constructions.
Separate, preferably rotatable, guides can be provided for each of the flexible pulling members.
A motor can be present, preferably an electric motor, for driving the drive train. Embodiments comprising an electric motor and a spindle drive as linear drive device can be particularly preferred. Other embodiments with hydraulic cylinders as drive device and a pump (with pump motor) are in principle also conceivable according to the invention.
The motor can be coupled to the linear drive device, preferably coupled to the two or more linear drive devices, via a jaw coupling comprising an elastomeric coupling element (German: "Elastomerkupplung").
Jaw couplings with an elastomeric coupling element have the advantage that the motion of the motor can be transmitted to the linear drive device(s) smoothly and without jerks.
The first end of the pulling member can preferably be attached to the cooling plates through a common plate support frame,

which is movable relative to the device frame and
which support frame is adapted to move the cooling plates relative to the device frame along the first axis.

In this way a relative motion of the cooling plates which are driven by a common drive train can be achieved easily.
In such embodiments the device frame and/or the plate support frame can include elongated holes, preferably for each cooling plate separately, in which pins on the cooling plates protrude for guiding the cooling plates along the first axis for facilitating the movability relative to the plate support frame.
Stops on the device frame can be used to keep the cooling plates in the first positions or the second positions (depending on which ones are lower) if the first axis is oriented vertically.
Lower positions in the elongated holes can in certain examples embody the stops.
The mounting device according to the invention can be embodied by the plate support frame and/or other component parts for fixing the pulling member to the cooling plates.
The guide can be a (rotatable) sprocket. In embodiments with more than one guide according to the invention each guide can be a separate sprocket.
Each guide itself can include separate guide elements. For example two guide elements, such as sprockets, can be used to redirect the flexible pulling member more than once in order to position and orient the pulling member as desired.
The flexible pulling member can comprise a chain, a belt, a cable and/or a rope (or of course several copies if there is more than one pulling member). Particularly preferred embodiments make use of one or more chains, in particular roller chains. Chains can be operated over long operation times with very little to no lubrication necessary which is beneficial if the presence of potential contaminants has to be limited, such as for example in biopharmaceutical production processes.
It can be provided that the flexible pulling member is spring loaded and there is a sensor for sensing, if the pulling member is under tension by the spring load. In this way a failure of the pulling member or some other element can be detected when the tension of the pulling member drops away.
In particular, in embodiments where the first axis is oriented vertically it can be provided that the pulling member is under tension at all times, such that the sensing of the tension on the pulling member is particularly reliable.
A limit switch can be arranged at the linear drive device (or several limit switches if there is more than one linear drive device) in order to detect a position of the linear drive device in which the cooling plates are in the first positions.
The limit switch can preferably be of a type with a lever, on the distal end of which a roller is attached (German: "Rollenhebelschalter").
Additionally or alternatively, rods attached on the cooling plates can be used in conjunction with sensors on the device frame in order to ascertain the correct positioning of the cooling plates.
Further details and advantages are apparent from the figure and the accompanying figure description. The figures show:

Fig. 1: schematically an embodiment of the invention and
Fig. 2: schematically a plate freezer according to the invention together with a cooling device for cooling (or heating) a cooling medium for the plate freezer.

The embodiment of the plate freezer 1 according to the invention shown in Fig. 1 comprises a device frame 2 which is only partly shown for an unobstructed depiction.
Cooling plates 3 are arranged horizontally along a first, vertical axis X1. In the figure the cooling plates 3 are in the first position, where containers (not depicted) of to be frozen goods can be arranged between the cooling plates. For a clear view of the drive train 4 the top most cooling plate 3 is not depicted.
The containers which can be used with the plate freezer 1 according to the invention can be specially adapted for storing and transporting biopharmaceutical liquids, for example as described in WO 2018129576 A1 . They can contain a hard outer shell, made from metal or the like, a flexible inner bag for holding the liquid and optionally one or more foam bodies for protecting the liquid and for compensating the volume expansion of the liquid during freezing.
The drive train 4 is configured to lift the cooling plates 3 into positions where each of the containers is in contact with both neighbouring cooling plates 3.
The drive train 4 comprises an electric motor 14, which is coupled to two linear drive devices 5 (here: spindle drives) via a jaw coupling 14, which are both mounted on the device frame 2.
The output sides 9 of the spindle drives are connected to a bar 12 which is movable along the second axis X2 and in this case embodied as a straight bar 12 with rectangular cross section. To this bar 12 there are attached the second ends 8 of four flexible pulling members 6, which are roller chains in this example.
The other, first ends 7 of the pulling member 6 are connected to plate support frame 14 for pulling the support frame upwards along the first axis X1.
The pulling members 6 are lead over guides 10, in this case rotatable sprockets, for redirecting the pulling members 6 from the pulling motion along the second axis X2 of the output sides 9 of the linear drive devices 5, which is imparted to the bar 12 and the second ends 8 of the pulling members 6, to the upwards pulling motion along the axis X1 for lifting the plate support frame 14.
There are in total four guides 10 for converting the linear motion along the second axis X2 created by the linear drive devices 5 into lifting motions of the first ends 7 of the pulling member 6 near the four corners of the cooling plates 3. In total six guides 10 (sprockets) are provided.
Not all linear drive devices 5, pulling members 6 and guides 10 are furnished with reference numerals in order to avoid an overloaded depiction.
The plate support frame 14 comprises a plate at the bottom of the apparatus depicted in Fig. 1. By lifting this plate, the cooling plates 3 are also lifted, either with the containers in between the cooling plates or not.
The device frame 2 furthermore comprises a plate with elongated holes 15 which act as guiding devices for the cooling plates 3. There are pins mounted to the cooling plates (visible in the elongated holes 15) in order to achieve this guiding effect. In the lower position (i.e. the first positions of the cooling plates, as depicted in Fig. 1) in which all pins are at the lower end of the elongated holes 15, these lower ends of the elongated holes 15 act as stops to keep the cooling plates 3 in the first positions.
By lifting the cooling plates 3 as described above the cooling plates 3 can be moved into the second positions with smaller relative distances compared to the first positions. Moving the cooling plates 3 upwards in this way successively creates contact between each cooling plate 3 and both adjacent containers (or other cooling plates 3 if a container is not present). I.e. the lower cooling plates 3 "pick up" the cooling plates 3 and the containers above. In this configuration the heat transfer between the containers and the cooling plates 3 is improved drastically.
The top-most cooling plate 3 is mounted to the device frame 2 and/or just remains in position by virtue of its weight.
At the same time

the containers can be easily moved into the spaces between the cooling plates 3 when the same are in the first positions depicted in Fig. 1,
the cooling plates 3 can just as easily be moved into the second positions for improved cooling capability, and
no hydraulic cylinders are necessary for a compact drive train for driving the motion of the cooling plates 3.

Rods 16 together with sensors can be used to ascertain the correct desired positioning of the cooling plates.
Fig. 2 schematically shows the plate freezer 1 together with a cooling device 19 which provides cooled or heated thermo oil to the cooling plates 3 of the plate freezer 1, i.e. the plate freezer can also be used to thaw the goods after freezing.
As Fig. 2 also shows, the plate freezer 1 can preferably be inside a thermally insulated housing.
Additionally, there are a cooling medium distributor 17 and a cooling medium collector 18 for distributing and collecting cooling medium to and from the different cooling plates 3. The cooling medium distributor 17 and the cooling medium collector 18 are in fluid communication with the cooling device 16 via a central supply line and a central return line.

Claims

Plate freezer, in particular for freezing and/or thawing biopharmaceutical fluids, comprising
- a device frame (2),

- a plurality of cooling plates (3) mounted on the device frame so as to be movable linearly substantially along a first axis (X1) with respect to the device frame from first relative positions to second relative positions and/or from the second relative positions to the first relative positions and

- a drive train (4) for driving the movement of the cooling plates (3),
wherein first distances present between neighbouring cooling plates (3) in the first relative positions are large enough to admit containers for to be cooled and/or heated goods between the cooling plates (3) and second distances present between neighbouring cooling plates (3) in the second relative positions are smaller than in the first relative positions, characterized in that the drive train (4) comprises
- a linear drive device (5), in particular a spindle drive, for creating a linear drive motion substantially along a second axis (X2), which is transversal with respect to the first axis (X1),

- a flexible pulling member (6), in particular a chain, for pulling the cooling plates (3) along the first axis, the flexible pulling member (6) comprising a first end (7) and a second end (8), wherein the first end (7) of the flexible pulling member is attached to the cooling plates (3) and/or a mounting device for the cooling plates (3) and the second end (8) of the flexible pulling member (6) is attached to an output side (9) of the linear drive device (5), and

- a, preferably rotatable, guide (10) mounted on the device frame (2) for redirecting the flexible pulling member (6) from an orientation along the first axis (X1) for pulling the cooling plates (3) to an orientation along the second axis (X2) for being pulled by the linear drive device (5).
Plate freezer according to claim 1, wherein the first axis (X1) is substantially vertical, the flexible pulling member (6) is arranged to pull the cooling plates (3) substantially upwards, and the second axis (X2) is substantially horizontal.
Plate freezer according to one of the preceding claims, wherein two or more linear drive devices (5) for creating the linear drive motion substantially along a second axis (X2) are provided.
Plate freezer according to one of the preceding claims, wherein the output side (9) of the linear drive device (5), preferably of the two or more linear drive devices (5), is connected to a bar (12), to which the flexible pulling member (6) is attached.
Plate freezer according to one of the preceding claims, wherein a plurality of flexible pulling members (6), preferably four flexible pulling members (6), are provided, all of which are preferably connected to the bar (12).
Plate freezer according to claim 5, wherein separate guides (10) are provided for each of the flexible pulling members (6).
Plate freezer according to one of the preceding claims, wherein a, preferably electric, motor (13) for driving the drive train (4) is provided.
Plate freezer according to claim 7, wherein the motor (13) is coupled to the linear drive device (5), preferably coupled to the two or more linear drive devices (5), via a jaw coupling (14).
Plate freezer according to one of the preceding claims, wherein the first end (7) of the pulling member (6) is attached to the cooling plates (3) through a common plate support frame (14),
- which is movable relative to the device frame (2) and

- which support frame (14) is adapted to move the cooling plates (3) relative to the device frame (2) along the first axis (X1).
Plate freezer according to one of the preceding claims, wherein the device frame (2) and/or the plate support frame (14) includes elongated holes (15), preferably for each cooling plates (3) separately, in which pins on the cooling plates (3) protrude for guiding the cooling plates (3) along the first axis (X1).
Plate freezer according to one of the preceding claims, wherein the guide (10) is a sprocket.
Plate freezer according to one of the preceding claims, wherein the flexible pulling member (6) comprises a chain, a belt, a cable and/or a rope.
Plate freezer according to one of the preceding claims, wherein the flexible pulling member (6) is spring loaded and there is a sensor for sensing, if the pulling member (6) is under tension by the spring load.
Plate freezer according to one of the preceding claims, wherein a limit switch is arranged at the linear drive device (5) in order to detect a position of the linear drive device (5) in which the cooling plates (3) are in the first positions.
Usage of a plate freezer (1) according to one of the preceding claims for cooling, freezing, heating and/or thawing a biopharmaceutical liquid.