AT505236B1 - DEVICE FOR DISTRIBUTING LIQUID MEDIA IN COLUMNS - Google Patents

Description

2 AT 505 236 B1

The invention relates to a device for distributing liquid media in separation columns, in particular for the laboratory scale, which has a jacket, inlet and outlet lines and inside one or more provided with inlet / outlet manifold / collector.

Column chromatography is a technique widely used in chemical and biopharmaceutical process engineering to separate mixtures of substances into their individual components, the separation being based on different principles. These separation principles have been extensively described in the art, and include, for example, size exclusion, cation exchange, anion exchange, and gel filtration chromatography. One particular chromatographic technique is Simulated Moving Bed (SMB) chromatography, in which a quasi-continuous countercurrent is generated in a fixed bed. The usual system designs use at least four correspondingly interconnected columns. A development of this embodiment is the so-called "single-column SMB", in which the countercurrent principle is accomplished by the indexing of the inlets and outlets at different points directly in bed. This simpler structure and in particular the elimination of the hose connections between the individual columns lead to a simpler cleaning and consequently sterilization of the components involved. This makes SMB chromatography interesting as a continuous purification process in the biopharmaceutical industry. SMB chromatography is described in detail in the relevant literature. For a detailed description see, for example, US Patent 5,156,736, Schoenrock and Austrian Patent AT412,258 B, Vogelbusch Gesellschaft M.B.H .. An exemplary separation process of a ternary mixture is described later.

In large-scale SMB chromatography columns, the introduction or removal of the liquid (either of the mixture or of the pure component) takes place through tubes which are provided with corresponding openings or slits. For separation columns on a laboratory scale, this embodiment of the manifold or collector is not suitable due to the smaller dimensions. Furthermore, there would be the danger that the holes provided in the distributor or collector pipes would be clogged by the packing material and thus the separation would be prevented. The packing materials used in separation columns for the chromatographic separation task generally have a separation particle diameter of 1 pm - 300 pm. These materials may be approximately spherical or even irregular. For analytical and preparative separation tasks one usually uses materials with separation grain sizes < 40 pm. For the purpose of process development or process optimization, separating materials are packed in columns that have been developed for industrial separation tasks. They usually have a cut-off diameter of > 40 pm.

The construction of the fittings is of great importance for the uniform distribution of the liquid flow over the cross section of the column packing. The liquid stream, which is supplied to the column via a capillary or a hose, must be evenly distributed at the column inlet. An uneven distribution would significantly degrade the separation performance of the column. Currently, this distribution of the liquid is usually achieved by distributor plates with specially made grooves, nets or simple glass balls. Often, however, only the tube or capillary is introduced at the column cover. At present there is no device with which it is possible under controlled conditions to supply or remove a uniformly distributed liquid flow within a laboratory separation column. Therefore, laboratory-scale separation tasks are limited to processes in which the feeds are fed in at the top and the drains are collected at the bottom of the column. Processes in which either a partial stream fed at a different location than at the column inlet and discharged at the column outlet, can not currently be performed on a laboratory scale due to lack of distribution device.

By way of example, a separation of a ternary mixture (A, B and C) by means of single-column SMB according to the prior art will be described below by way of example. The ternary 3 AT 505 236 B1

Mixture (A, B and C) is fed via a feed line at the top of the separation column. Due to the different retention times of the three substances A, B and C (with the retention times of the three pure substances increasing in the following order: A <B <C), A migrates very rapidly through the separation column while C is strongly retained. As C accumulates at the column entrance, substances A and B move through the column, but at different rates of migration. This difference in migration speeds further separates the resulting binary mixture (A and B). Due to the higher retention time of B, B accumulates in the middle of the separation column while A migrates up to the bottom of the column. If it were now possible to supply or remove liquid streams at any point of a separation column, then in the preceding example the pure substance A at the bottom of the column could be withdrawn while the pure substance B could be withdrawn in the center of the column.

The invention is therefore an object of the invention to provide a device of the type mentioned, with which the liquid flow can be uniformly applied or withdrawn at certain points within the column packing of the separation column.

According to the invention the object is achieved in that the distributor / collector are formed of sintered or porous dimensionally stable material. Due to the channels or pores inherently present in the sintered or porous material, the liquid stream to be introduced is finely distributed over the entire cross-section, whereby at the same time the possibility of miniaturization of separation columns for the laboratory scale is given. The advantage of the device according to the invention is therefore that a mixture of substances can be evenly distributed over the cross section of a laboratory separation column or deducted. This ensures the achievement of a maximum separation efficiency under equivalent conditions for a large-scale separation. In addition, the device according to the invention offers the possibility of introducing partial liquid streams anywhere in the separating column, taking into account the requirement that a large part of the column cross-section be expanded for both the flow through the medium and for the movement of the absorbent typical in chromatography and shrinkage depending on the loading of the separation medium is available.

In a preferred embodiment, each manifold / collector may be made of sintered or porous dimensionally stable material and may be formed as a tube or elongated cuboid provided with an axial bore. This design allows for easy manufacture of the manifold / collector of the present invention using any method known in the art without sacrificing distribution characteristics.

In yet another preferred embodiment, the manifolds / collectors may be made of sintered metal. In another preferred embodiment, the manifolds / collectors may be made of sintered ceramic. The use of sintered metal or sintered ceramic technology allows the production of manifolds with a defined pore size with simultaneously defined porosity. The pore size together with the porosity of the manifold / collector ensures a fine distribution of the substance mixture over the column cross-section.

In a further embodiment it can be provided that the volume resistance of the collector / distributor is set by the choice of the wall thickness of the distributor / collector tubes. The thicker the wall thickness of the manifold / collector tubes, the longer the path for the substances to travel through the channels or pores, to subsequently encounter the packing material, i. the volume resistance through the distributor / collector is greater. This requires that the pressure necessary to deliver the liquid flow through the manifolds / collectors must be high. This can lead to the loss of activity especially in pressure-sensitive biomolecules. In particular, when withdrawing the pure substances, this is important because the recoverable suppressant is limited. Consequently, by reducing the 4 AT 505 236 B1

Volume resistance (lower wall thickness) are reduced for the application of the liquid flows required positive or negative pressures, whereby pressure-sensitive molecules can be introduced through the distributor / collector according to the invention in the separation column or withdrawn from these. Furthermore, the column can be designed in a simpler design due to the lower operating pressures. Furthermore, by selecting the ratio between the diameter of the inner bore and the thickness of the porous material, the individual pressure losses can be adjusted so that a uniform distribution of the liquid flows over the entire column cross-section is ensured.

In development of the present invention can be provided that the manifold / collector are etched before installation in the device on the outer surface. The manifolds / collectors are etched mainly with an acid, the acid preferably being hydrochloric acid. The etching of the manifold / collector causes the pores sealed at the surfaces of the sintered metal or sintered ceramic material to be opened by the manufacturing process. This, in turn, ensures that the liquid flow can escape from all the pores inherent in the sintered material and thus a uniform distribution of the liquid flow over the cross section takes place. This is particularly important when removing liquid from the separation column of importance because the necessary negative pressure can not be chosen arbitrarily high.

Preferably, in the device according to the invention, the porosity of the manifold / collector may increase over the course, starting from the connection to the inlet and / or outlet. The continuous increase in porosity means that due to the lower porosity in the vicinity of the connection to the inlet and / or outlet that portion of the liquid flow can escape through the pores in relation to the total volume flow is small, and thus liquid to the opposite End of the distributor / collector can penetrate. Again, a uniform distribution of the liquid over the entire cross section of the separation column is achieved.

In a further embodiment, the manifold (s) may be sealed using a sealing technique such as sealing. Gluing, fixed on webs or supports or connected to the inlet and / or outlet. By using a sealing connection technique, on the one hand, the improper discharge of the media at the connection point is prevented and, on the other hand, an uneven distribution of the liquid flow caused by the exit is prevented. As the manifolds are attached to supports only at both ends, the liquid flow can escape from the manifolds throughout the circumference. This represents a significant improvement over traditional attachment to lands extending across the entire column diameter. Using conventional lands, an entire face of the manifold / collector is closed by the land and thus is unavailable for liquid dispensing.

The object of the invention will be described below with reference to a preferred embodiment and the accompanying drawings.

Show it:

Figure 1 is a vertical section of a laboratory separation column using three distributor / collector devices according to the invention and a top and bottom distributor;

Figure 2 is a vertical section through a head distributor for a separation column for the laboratory scale;

Figure 3 is a plan view of the distributor / collector device according to the invention, wherein the sintered tubes have been omitted for clarity;

Figure 4 is a section through the inventive distributor / collector device according to line IV-IV of Figure 3, wherein the sintered tubes have been omitted for clarity; 5 AT 505 236 B1

Figure 5 is a section of the distributor / collector device according to the invention along the line V-V of Figure 3;

Figure 6 is a section through a keyed fitting intended to close the opening necessary to insert the distribution tube into the manifold / collector;

Figure 7 shows a clamping nipple with an inner and an outer thread, which clamps the fitting of Figure 6 in the corresponding opening and thereby seals the fitting against the manifold / collector;

8 shows a threaded nipple with a central bore along the longitudinal axis, which on the one hand receives the supply and discharge line and on the other hand seals the transition point between screw nipple and fitting piece by means of sealing ring;

Figure 9 is a sectional view of the distributor / collector device according to the invention with built-in sintered tubes and fitting pieces;

10 shows a section of the distributor / collector device according to the invention with built-in fitting, clamping and screw nipple along line X-X of Figure 9.

A separation column for laboratory operation is shown schematically in FIG. 1 and consists essentially of the head distributor 1, the sump distributor 2, one or more distributor / collector devices 3 according to the invention and a plurality of column sections 4. The individual components of the separation column are connected via a threaded rod 5 and corresponding nuts 5 'connected to each other, wherein between the individual parts O-rings 6 are inserted into corresponding grooves to give a dense separation column. The head distributor 1 and the sump distributor 2 are identical, but are mirror-inverted in the composite separation column. However, a mirror-inverted version of the head 1 or sump distributor 2 is not mandatory. Thus, in another embodiment, the head distributor is provided with its own filling device, which is not provided in the sump distributor, so that these components are no longer the same. In general, the sump distributor is a collector which collects the medium over the column cross-section and supplies it to a central drain. The basic structure of a head 1 or sump distributor 2 is shown in FIG. The head 1 or sump distributor 2 consists of a head part 12 and a lower part 16, which are connected to each other by means of screws 8. Between the two parts 12 and 16, an O-ring 6 is provided in a corresponding groove 17 for the purpose of sealing. For the purpose of liquid application to the separation column, the head part 12 has a central bore 9, whose lower end opens into a star-shaped groove arrangement 10. The liquid stream is conveyed by means of a pump via a line to the central bore 9, and subsequently the liquid flow is distributed via the groove arrangement 10 on the sintered plate 11. Through the sintering plate 11, the liquid flow is applied uniformly over the cross section of the separation column. The sintered plate 11 rests on a plurality of support projections 17, which are an integral part of the lower part 16. The sintered plate 11 is clamped by the screws 8 between the head part 12 and the lower part 16. The fluid stream migrates after exiting the sintering plate 11 through the filled with packing material column in the direction of the sump manifold 2. The individual substances of the liquid stream are retained due to the interactions between the individual substances and the packing material different degrees of packing material and thus migrate at different speeds.

As mentioned earlier, an SMB chromatography column has one or more manifold / collector means according to the invention. These serve the purpose of introducing a feed or elution buffer ("eluent") at a preselected location along the column path, or to withdraw a substance or mixture of substances (raffinate or extract) at a preselected location. The distributor / collector device 3 according to the invention consists essentially of a ring 18, on the periphery of which bores 14 for receiving the threaded rods 5 (see FIG. 1) are present (FIG. 3) in order to connect the individual components of the separation column tightly to one another. For the application or removal of the fluids, sintered tubes 15 (FIG. 5) are arranged within the ring 18 and on both sides

Ends on the supports 19, e.g. fastened by gluing or the like or by means of positive connection. In the present example, the sintered tubes in the form of a square outer cross section, the side length of which is 2 mm, and are provided with an inner bore with a diameter of 1 mm. These were cut out (eroded) by the manufacturer from a 2 mm thick plate (SIKA-R, GKN Sinter Metals). As a result, the sintered tubes on the two cut sides are treated by the erosion process, while the remaining two sides are untreated, so that the surfaces of the sintered tubes 15 have a different nature, which in turn adversely affect the porosity on the surface of the sintered tubes 15. To guarantee even distribution of the liquid stream, the sintered tubes 15 were etched in 25% hydrochloric acid (HCl) for 10 minutes prior to installation in the ring 18. This ensures that the pores of the side surfaces closed by the erosion are opened, and thus are available for distributing the liquid flow. The supports 19 themselves form an integral part of the ring 18, as shown in FIG. The arrangement of the sintered tubes in the distributor / collector device according to the invention and the connection to the supply and discharge lines are shown in FIGS. 9 and 10. In the present example, 3 sintered tubes 15 are installed in the manifold / collector device according to the invention, which are respectively secured to the supports 19 at both ends (Figure 9). Each sintered tube 15 is thereby impinged by a separate hose line. In this configuration, only the sintered tubes are in the column, which are glued to supports, whereby disturbing support webs can be avoided (Figures 3, 4 and 10). For this purpose, a connection arrangement 13 is provided in the ring 18 for each sintered tube. The connection arrangement consists of three parts, namely the fitting piece 21 (FIG. 6), the clamping nipple 25 (FIG. 7) and the screw nipple 26 (FIG. 8). The fitting 21 (Figure 6) consists of a rotationally symmetric body 28 and a wedge 21 mounted thereon, one end of the rotationally symmetric body 28 being adapted to the inner diameter of the ring, i. this end has a corresponding rounding (FIG. 6). Furthermore, two bores 23, 24 are provided in the body 28. As already mentioned above, incoming or outgoing liquid streams are distributed or withdrawn via the sintered tubes 15. For this purpose, the supply and discharge lines are attached to cannulas 15 ', which in turn are connected to the sintered tubes 15. This compound, in this case an adhesive bond, is shown in detail A of FIG. The cannula 15 'abuts against the sintered tube 15 and is glued to the joint. The bore of the sintered tube 15 is countersunk on this side, wherein the outer diameter of the countersink corresponds to the inner diameter of the cannula 15 '(detail A, FIG. 9). This constructive design of the transition between the cannula 15 'and the sintered tube 15 ensures a continuous transition and thus prevents the formation of dead spaces in which it could lead to contamination of the incoming and exiting liquid streams. The cooperation of the three parts 20, 25 and 26 of the connection arrangement 13 is shown in FIG. After the cannula 15 'has been fastened to the sintering tube 15, as explained above, these are inserted into the distributor / collector with the fitting 20 removed. Subsequently, the fitting 20 is inserted with the rounded end in the terminal assembly 13 in such a way that the wedge 21 in the keyway 22 (Figure 5) engages to rotate the fitting 20 in the terminal assembly 13 when screwing the Klemmnipples 25th to prevent, which ensures that the curvature of the inner diameter of the columns is exactly continued and thereby the flow inside the column is not disturbed by a projecting fitting piece (Figure 9, 10). The Klemmnippel 25 takes on two tasks. First, the nipple 25 secures the fitting 20 in the fitting assembly 13 and secondly, the nipple presses the O-ring 29 located between the fitting 20 and the fitting assembly 13 against the corresponding bore in the fitting assembly 13 (FIGS. 6 and 10). whereby the connection between fitting 20 and manifold / collector is sealed. The clamping nipple 25 has in addition to receiving the screw nipple 26 on an internal thread, in which a bore 27 is provided, through which the supply and discharge hose is inserted into the connection assembly 13. The screw nipple 26 is first slipped over the attached to the distribution tube 15 cannula 15 'and then screwed into the nipple 25 (Figure 10). To the cannula 15 'against the

Claims (8)

To seal fitting piece 20, a corresponding groove is provided in the fitting piece 20, which receives an O-ring 31 (Figure 6). The O-ring 31 is clamped by the screw nipple 26, through the inner bore 27, the cannula 15 'runs. Since the sintered tubes are drilled as mentioned above, the end opposite the cannula 15 'must also be closed. In the present case, this is done by gluing the opening. By means of the distributor / collector device according to the invention, it is now possible for liquid partial streams to be supplied differently to the column during operation, such as fresh elution buffer, wherein separate pure substances can be withdrawn at a different location at the same time without the respective liquid stream having to pass through the entire column , This is particularly important in the process development and optimization, since on a laboratory scale those parameters or separation principles are to be found with which the substance mixtures are later to be separated on an industrial scale. Also, the combination of different separation principles, such as cation exchangers and anion exchangers, HIC and ion exchanger, gel filtration and ion exchanger, to name but a few, can be realized with the inventive distributor / collector device on a laboratory scale. In summary, the distributor / collector device according to the invention represents a significant advance in process development and optimization, in that the proven SMB chromatography can now also be carried out on a laboratory scale. 1. Device for distributing liquid media in separation columns, in particular for the laboratory scale, which has a jacket, inlet and outlet lines and inside one or more provided with inlet and outlet manifold / collector, characterized in that the distributor / collector (15) are formed of sintered or porous dimensionally stable material. 2. Device according to claim 1, characterized in that each distributor / collector (15) consists of sintered or porous dimensionally stable material and is designed as a tube or oblong, provided with an axial bore cuboid. 3. Device according to claim 1 or 2, characterized in that the distributor / collector (15) are made of sintered metal. 4. Device according to claim 1 or 2, characterized in that the distributor / collector (15) are made of sintered ceramic. 5. Device according to one of claims 2 to 4, characterized in that the volume resistance of the collector / distributor (15) is set by the choice of the wall thickness of the distributor / collector tubes. 6. Device according to one of claims 1 to 5, characterized in that the manifold / collector (15) are etched prior to installation in the device on the outer surface. 7. Device according to one of claims 1 to 6, characterized in that starting from the connection of the manifold / collector (15) to the inlet and / or outlet, the porosity of the manifold / collector (15) increases over its longitudinal course. A device according to any one of claims 1 to 7, characterized in that the distributor / collector (15) is constructed using a sealing connection technique, e.g. Gluing, on webs or supports (19) attached or connected to the inlet and / or outlet.