Rotary valve, system, and method

Abstract

The invention relates to a rotary valve having a stator (1) and a rotor (2), wherein: the stator (1) and the rotor (2) are rotatable relative to each other about a central axis (3); the stator (1) has, at a stator inner surface (6), a plurality of openings (4), from each of which a channel extends to a corresponding port at a stator outer surface (5); the rotor (2) has a plurality of connection paths (8-1, 8-2, 8-3) which extend along a rotor inner surface (7); the stator inner surface (6) and the rotor inner surface (7) are in fluid-tight contact; a first to an eighth opening (4-1, 4-2,..., 4-8) are provided at the stator inner surface (6); the central axis (3) extends through the first opening (4-1); a radial connection path (8-1) is provided which extends in the radial direction with respect to the central axis (3); at least two additional connection paths (8-2, 8-3) are provided; and the rotary valve can be brought into at least five positions. The invention further relates to a system and to a method.

Description

[0001] 65204 / MB / -

[0002] University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0003] Rotary valve, system and procedure

[0004] The present invention relates to a rotary valve, a system comprising such a rotary valve, and a method for preparing a sample using a rotary valve.

[0005] Rotary valves are known in various designs in the prior art. In the field of chemical analysis, for example, they are used to feed liquid samples into a chromatography system in order to increase the speed of the analysis or to control the amount of sample being analyzed.

[0006] The basic structure of known rotary valves consists of a rotor and a stator, with the rotor being driven by a drive unit and thus able to rotate relative to the stator. The rotor and stator are in contact with each other over a surface. The rotor typically has one or more connecting channels (also referred to as slots, channels, or grooves), while the stator typically has several openings, which are located on the contact surface with the rotor. Each of these openings corresponds fluid-conductingly to a port on the stator, to which various external devices can be connected.

[0007] The connection paths are arranged such that in a specific position of the rotor they have two or more openings (and thus those with the respective connections 65204 / MB / -

[0008] University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT) connected external facilities) in a fluid-conducting manner. If the rotor is rotated relative to the stator and moved into a different position, the connecting paths can connect two or more other openings.

[0009] A specific, previously known design of a rotary valve is the so-called injector valve. Here, an externally arranged section of tubing (the so-called injection loop) connects two openings. In one position of the rotary valve, the injection loop can be filled with sample, while a solvent (in the case of chromatography, the so-called mobile phase) is pumped to a chromatographic analyzer or other analytical instrument. In another position, the solvent is pumped through the injection loop, thereby forcing the sample out of the injection loop and into the chromatographic analyzer or other analytical instrument. The length and inner diameter of the injection loop determine the volume of the dispensed sample.This ensures that a constant volume is reproducibly injected into the chromatography or analysis equipment, enabling the extraction of quantitative data from an analysis.

[0010] In many cases, it is desirable to prepare the sample before introducing it into the chromatography or analytical equipment, for example to increase the concentration of the analytes to be analyzed, to eliminate substances that can produce artifacts (interferences) during the determination of the analytes, or to replace the sample medium (matrix) if it is not compatible with the working principle of the chromatography or analytical equipment.

[0011] The most commonly used technique for this purpose in the prior art is solid phase extraction (SPE). In this process, a solid resin is packed into a reservoir with two ports (also called a column or cartridge), through which fluids can flow in and out.

[0012] Depending on the specific resin used, the analytes of interest can bind to it when a sample flows through the column. Analytes of interest in the matrix, however, are not bound by the resin and can be discarded. In a further step, the analytes bound to the resin can be removed (eluted) by flushing the column with a suitable eluent, after which the resulting solution can be injected into the chromatography or analytical instrument. Besides the analytes, certain other substances (interferences) can also bind to the resin, but these cannot be eluted, or at least not completely. Therefore, the service life of such columns is limited.

[0013] Solid-phase extraction can be performed manually or automatically. For the latter, it is known in the art to insert a column into the injection loop of an injector valve described above, so that the sample flows through the column and is thereby processed when introduced into the injection loop. If the chemistry of the solid-phase extraction column and the analytical column of the chromatography system is identical, no separate elution step is required, since the analytes bound to the solid-phase extraction column are transported to the analytical column by the mobile phase after the valve switches. This arrangement is also referred to as a "switching valve".

[0014] The operation of such a switching valve can be carried out fully automatically and is advantageous in that all analytes retained in the column can be transferred to the chromatography or analysis equipment and the analytes do not need to be eluted in a separate step.

[0015] However, such switching valves also have disadvantages: After the elution step, some interferences can remain bound to the resin, reducing the column's performance with each use. Furthermore, the high pressure to which the resin is subjected most of the time leads to resin compaction, resulting in higher flow resistance and thus a greater pressure drop. Finally, the column chemistry must be compatible with that of the chromatographic column, limiting the possible combinations. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0016] These disadvantages can be overcome by an automated exchange of the columns, which can be done using a so-called column changer, but this is expensive to purchase, has a large footprint and is therefore typically not suitable for portable systems.

[0017] Furthermore, it is known to use so-called bead injection, in which a suspended resin material is used to pack a solid-phase extraction column. The column typically includes a frit that retains the resin when the suspension flows through the column in one direction. When a fluid is passed through the column in the opposite direction, the resin is flushed out.

[0018] One advantage of bead injection is that the resin can be replaced at any time without having to remove the column itself. Furthermore, there is no need to rely on a pre-fabricated column, which increases application flexibility and reduces operating and replacement costs.

[0019] Attempts have already been made to combine the advantages of diverter valves with inline columns and bead injection by incorporating the frit-fed column, familiar from bead injection, into the injection loop. However, such a design necessitates a multitude of different flow paths and also imposes complex requirements on the applicable pressure and flow regimes. Therefore, a combination of two or three rotary valves is typically required to provide the necessary functionalities.

[0020] The present invention therefore aims to create a rotary valve that combines the functionalities of different known types of rotary valves in a single rotary valve, thereby enabling the smallest possible space requirement while maintaining high portability.

[0021] This task is now solved in particular by a rotary valve that has at least five different valve positions, in which, by the action of a 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0022] Due to the relative movement between the stator and rotor, different flow paths can be created.

[0023] In this design, openings are provided on one surface of the stator, also known as the inner stator surface. These openings lead via conductors or channels to terminals, which are also located on the stator and to which external devices, such as connecting cables, cable loops, containers, or other equipment, can be connected. These terminals may be equipped with internal threads. Each opening typically corresponds to a single terminal.

[0024] The rotor typically features several connecting channels, which form recesses on the rotor's inner surface or run as channels within the rotor. The term "connecting channel," also referred to as "radial connecting channel" or "further connecting channel," encompasses both surface (i.e., exposed) grooves or milled areas that only form a fluid-conducting channel when interacting with the stator's inner surface, and channels that have at least one inlet or outlet on the rotor's inner surface. These connecting channels, also called rotor channels or grooves, are generally arranged or designed to fluidly connect at least two openings and their corresponding ports in specific relative positions between the rotor and stator.

[0025] In particular, the rotor is rotatable relative to the stator along a central axis. The central axis can be arranged perpendicular to both the inner surface of the stator and the inner surface of the rotor.

[0026] Preferably, the rotor of the rotary valve described here includes at least one connecting path that extends radially with respect to the central axis; this path is also referred to as a radial connecting path. The radial connecting path need not be perpendicular to the central axis. For example, depending on the geometry of the rotor's inner surface, the radial connecting path can also run at an angle other than 90° to the central axis. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0027] Furthermore, additional connecting routes are planned, typically two or three, although more are possible. These additional connecting routes are typically separate from each other, meaning they are not directly connected.

[0028] The preferred valve positions are as follows:

[0029] - a first position in which a first opening and a second opening are connected by the radial connection path,

[0030] - a second position of the rotary valve in which the first opening and an eighth opening are connected by the radial connecting path; and in which a sixth opening and a seventh opening are connected by a further connecting path,

[0031] - a third position of the rotary valve in which the first opening and a fifth opening are connected by the radial connection path,

[0032] - a fourth position of the rotary valve in which the first opening and a fourth opening are connected by the radial connecting path; and in which a third opening and the eighth opening are connected by a further connecting path; and in which a fifth opening and the sixth opening are connected by a further connecting path,

[0033] - a fifth position of the rotary valve in which the first opening and the sixth opening are connected by the radial connecting path; and in which the seventh opening and the eighth opening are connected by a further connecting path.

[0034] The rotary valve may have additional positions, although this is not strictly necessary for its intended use.

[0035] However, a sixth position may be provided, in which the first opening is joined by a further opening, namely a ninth opening through the

[0036] radial connection path are connected, with the further

[0037] In the sixth position of the rotary valve, no connection is made between openings. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0038] If necessary, one or more, in particular all, further connecting paths are designed as circular arcs, curved or linear. They run in relation to circles whose center is formed by the central axis, in particular tangentially or in the form of circular arcs.

[0039] Optionally, the rotary valve may have a seventh position in which the first opening and a tenth opening are connected by the radial connection path.

[0040] In one embodiment of the rotary valve described here, two further connection paths are provided, namely a second connection path and a third connection path. It may be provided that

[0041] - in the second position of the rotary valve, the sixth opening and the seventh opening are connected by the third connecting path,

[0042] - in the fourth position of the rotary valve, the third and eighth openings are connected by the third connecting path, and the fifth and sixth openings are connected by the second connecting path,

[0043] - in the fifth position of the rotary valve, the seventh opening and the eighth opening are connected by the second connecting path.

[0044] In this embodiment, the third to eighth openings can form the vertices of a regular hexagon, at the center of which lies the central axis or the first opening. The second and the optional ninth opening can be located inside or outside this hexagon, wherein it is particularly provided that the second and the optional ninth and / or tenth openings are located away from the direct connection between the first opening and the third to eighth openings, and / or that the second and the optional ninth and / or tenth openings are not aligned with the radial connection path if this connects the first opening to one of the third to eighth openings.

[0045] Other geometric designs for openings and connecting passages are fundamentally conceivable and also fall under the general concept of this description. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0046] The rotary valve described here can be used particularly advantageously in a system where the connections are linked to other devices.

[0047] If necessary, one or more of the following devices may be connected to corresponding ports or openings:

[0048] - the connection of the first opening with a bidirectional pump;

[0049] - the connection of the second opening to a sorbent container for receiving a sorbent or resin suspension or to a liquid supply system, such as in particular an autosampler;

[0050] - the connection of the optional ninth opening to a sample container, whereby the sample container can also be a sample supply device;

[0051] - the connection of the third opening and the connection of the fourth opening with a line connecting these two openings;

[0052] - the connection of the sixth opening and the connection of the eighth opening with a line connecting these two openings, wherein a filter cartridge is arranged in the course of this line;

[0053] - the connection of the fifth opening to an analytical device and / or to a chromatographic device;

[0054] - the connection of the seventh opening to a drainage or waste pipe.

[0055] The liquid supply system can be configured to guide one or more of the following to the connection of the second opening: sorbent or resin suspension, solvent, sample solution.

[0056] If provided for, the connection of the tenth opening can be connected to a solvent supply system, such as a solvent tank, or to another system, such as a gradient mixing system.

[0057] However, the solvent supply system can also be in direct contact with the pump; for example, the pump can be positioned between the solvent supply system and the first opening, in which case a tenth opening is not required. 65204 / MB / -

[0058] University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0059] If the system includes a liquid supply system, such as an autosampler in particular, the solvent supply system may also be part of the liquid supply system or it may be connected to the liquid supply system.

[0060] This system can be used in particular in a process for the preparation and / or analysis of samples. The process can include the following steps in different sequences:

[0061] - in the first position of the rotary valve: taking up sorbent material suspension from the sorbent container or from the liquid supply system, if necessary by means of the pump operated in suction mode (step a);

[0062] - in the first position of the rotary valve: operating the pump in suction mode and taking up liquid sample material from the liquid supply system (step b1);

[0063] - in the sixth position of the rotary valve: operating the pump in suction mode and drawing up liquid sample material from the sample container (step b2);

[0064] - in the second position of the rotary valve: pumping previously taken-up material, in particular sorbent material suspension, sample and / or solvent, by operating the pump in pump mode through the filter cartridge, whereby the solid sorbent material is retained in the filter cartridge (step c);

[0065] - in the fourth position of the rotary valve: operating the pump in pump mode so that the filter cartridge is permeated with solvent, the solvent eluting the sample material retained by the sorbent material and conveying it to the outlet of the fifth orifice and onward to the analytical or chromatographic apparatus; the solvent may be supplied by a solvent supply system directly connected to the pump, or located at the optionally provided outlet of the tenth orifice, or in operative contact with a liquid supply system (step d);

[0066] - In the third position of the rotary valve: operate the pump in pumping mode and pump solvent to the outlet of the fifth opening and in the direction of 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0067] Analysis or chromatography equipment so that the system is pressurized (step e).

[0068] Step b1 is performed specifically when using a rotary valve that does not have a sixth position and where the sample is supplied via a liquid supply system, such as an autosampler. In contrast, step b2 is performed when the rotary valve has a sixth position and the sample is supplied from a separate sample container. Steps b1 and b2 are therefore considered alternative steps. The reference to step b generally refers to either alternative step b1 or b2.

[0069] To remove sorbent material from the filter cartridge, the rotary valve can be in the fifth position, in which the pump is operated in pump mode and in which the solvent flows through the filter cartridge and is thereby removed from the filter cartridge (step f).

[0070] To introduce solvent into the system, solvent can be drawn from the solvent supply system using the pump operating in suction mode in a seventh position of the rotary valve (step g). Solvent can also be drawn from a liquid supply system; in this case, the rotary valve is in the first position in step g.

[0071] The following switching sequences or procedural sequences are among those possible:

[0072] - acbcd: normal analysis sequence with cartridge packing and subsequent sample introduction, followed by analysis;

[0073] - acbced: normal analysis sequence with packing of the cartridge and subsequent introduction of the sample, followed by the analysis, but with pressurization of the column prior to the analysis;

[0074] - bacd: Stacking of sample and sorbent suspension in the system before packing the cartridge, followed by analysis;

[0075] - backed: Stacking of sample and sorbent suspension in the system before packing the cartridge, followed by analysis, but with pressurization of the column prior to analysis; 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0076] - acbcgd: normal analysis sequence with cartridge packing and subsequent sample introduction, solvent aspiration, followed by analysis;

[0077] - acbcged: normal analysis sequence with packing of the cartridge and subsequent introduction of the sample, aspiration of solvent, followed by analysis, but with pressurization of the column prior to analysis;

[0078] - bacgd: Stacking of sample and sorbent suspension in the system prior to packing the cartridge, aspiration of solvent, followed by analysis;

[0079] - backed: Stacking of sample and sorbent suspension in the system before packing the cartridge, aspiration of solvent, followed by analysis, but with pressurization of the column before analysis;

[0080] - gacbcd: Stacking of solvent and sorbent suspension in the system prior to packing the cartridge, aspiration of sample, followed by analysis;

[0081] - gacbced: Stacking of solvent and sorbent suspension in the system before packing the cartridge, aspiration of sample followed by analysis, but with pressurization of the column before analysis;

[0082] - acgbcd: Packing the cartridge, stacking solvent and sample in the system, followed by analysis;

[0083] - acgbced: Packing the cartridge, stacking solvent and sample in the system, followed by analysis, but with pressurizing the column before analysis;

[0084] - gbacd: Stacking of solvent, sample and sorbent suspension in the system prior to packing the cartridge, followed by analysis;

[0085] - gbaced: Stacking of solvent, sample and sorbent suspension in the system prior to packing the cartridge, followed by analysis, but with pressurization of the column prior to analysis.

[0086] Optionally, the invention relates to a rotary valve with a stator and a rotor, wherein the stator and rotor are rotatable relative to each other about a central axis, wherein the stator has a plurality of openings on an inner surface, each of which has a channel extending to a corresponding connection on an outer surface, wherein the rotor has several connecting paths, and wherein the inner surface of the stator and the inner surface of the rotor are in fluid-tight contact, 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0087] If necessary, it is provided that a first to eighth opening is provided on the inner surface of the stator, with the central axis passing in particular through the first opening.

[0088] If necessary, a radial connection path is provided, which runs in a radial direction to the central axis.

[0089] If necessary, at least two further connecting routes are planned.

[0090] If applicable, it is planned that:

[0091] - in a first position of the rotary valve: the first opening and the second opening are connected by the radial connection path,

[0092] - in a second position of the rotary valve: the first opening and the eighth opening are connected by the radial connecting path; and the sixth opening and the seventh opening are connected by another connecting path,

[0093] - in a third position of the rotary valve: the first opening and the fifth opening are connected by the radial connection path,

[0094] - in a fourth position of the rotary valve: the first opening and the fourth opening are connected by the radial connecting path; the third opening and the eighth opening are connected by another connecting path; and the fifth opening and the sixth opening are connected by another connecting path,

[0095] - in a fifth position of the rotary valve: the first opening and the sixth opening are connected by the radial connecting path; and the seventh opening and the eighth opening are connected by another connecting path.

[0096] If necessary, it is provided that the further connecting paths in the first position of the rotary valve do not establish a connection between openings.

[0097] If necessary, it is provided that a ninth opening is also provided, that in a sixth position of the rotary valve the first opening and the ninth opening are connected by the radial connecting path, and that, if applicable, the 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT) further connecting paths in the sixth position of the rotary valve do not establish a connection between openings.

[0098] If necessary, it is provided that in a seventh position of the rotary valve: the first opening and a tenth opening are connected by the radial connection path.

[0099] If necessary, it is provided that in an eighth position of the rotary valve: the first opening and the seventh opening are connected by the radial connection path.

[0100] If necessary, the further connecting paths are designed to have the form of circular arcs, with the center of the corresponding circle being formed by the first opening.

[0101] If necessary, the further connecting paths are designed to be linear and may run tangentially with respect to a circle whose center is formed by the first opening.

[0102] If necessary, the central angle of the circular arcs is provided to be at least 60°, in particular between 60° and 79°, preferably between 71° and 79°.

[0103] If necessary, two, three or more additional connecting routes are planned.

[0104] If necessary, the third to eighth openings are provided for at the vertices of a first regular hexagon, the center of which is formed by the first opening.

[0105] If necessary, the length of the radial connection path is intended to correspond essentially to the distance between the first opening and the third to eighth openings. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0106] Optionally, it is provided that the stator inner surface and the rotor inner surface are essentially planar planes, or that the rotor has a frustoconical section whose smaller base area and lateral surface form the rotor inner surface, or that the rotor has a spherical segment-shaped section whose lateral surface forms the rotor inner surface.

[0107] Optionally, the invention relates to a system for preparing and optionally analyzing a sample containing an analytical material in a liquid medium, wherein the system comprises: a rotary valve as defined herein; a connecting line arranged between the connection of the third opening and the connection of the fourth opening; a filter cartridge arranged between the connection of the sixth opening and the connection of the eighth opening; a bidirectional pump connected to the connection of the first opening, having a suction mode and a pump mode; and a feed system, in particular an autosampler, connected to the connection of the second opening, wherein the liquid feed system is configured to supply sample, sorbent material suspension and optionally solvent.

[0108] Optionally, the invention relates to a system for preparing and optionally analyzing a sample containing an analytical material in a liquid medium, the system comprising: a rotary valve as defined herein; a connecting line arranged between the connection of the third opening and the connection of the fourth opening; a filter cartridge arranged between the connection of the sixth opening and the connection of the eighth opening; a bidirectional pump connected to the connection of the first opening, having a suction mode and a pump mode; a sample container connected to the connection of the ninth opening for receiving the sample; and a sorbent container connected to the connection of the second opening for receiving sorbent material suspension.

[0109] The filter cartridge may optionally include a retention element, in particular a filter frit, and a sorbent holding area, the sorbent holding area being located, in particular, between the retention element and the connection of the eighth opening. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0110] If applicable, it is provided that an analysis device is connected to the fifth opening, and / or that a waste line is connected to the seventh opening.

[0111] If necessary, the system may also include a solvent supply system connected to the tenth opening for the provision of a solvent.

[0112] The system may optionally include a solvent supply system connected to the pump for providing a solvent, and / or a solvent supply system coupled to the liquid supply system, in particular to the autosampler.

[0113] The invention may relate to a method for preparing and optionally analyzing a sample using a system as described herein, wherein the method comprises the following steps:

[0114] - Switching the rotary valve to the first position and then taking in sorbent material suspension, in particular from the sorbent container or from the liquid supply system (step a),

[0115] - Switching the rotary valve to the first position or leaving the rotary valve in the first position and then taking a sample from the liquid supply system using the pump operating in suction mode, or switching the rotary valve to the sixth position and then taking a sample from the sample container using the pump operating in suction mode (step b),

[0116] - Switching the rotary valve to the second position and then conveying the collected material, in particular sorbent material suspension, sample and / or solvent, by means of the pump operated in pump mode to the outlet of the seventh opening and through the filter cartridge, whereby the sorbent material is retained in the filter cartridge (step c),

[0117] - Switching the rotary valve to the fourth position and then conveying solvent through the filter cartridge using the pump operating in pump mode, and onward to the outlet of the fifth opening (step d). 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0118] The procedure may also include the following step:

[0119] - Switching the rotary valve to the third position and then conveying solvent to the outlet of the fifth opening using the pump operating in pump mode.

[0120] If necessary, the solution exiting the outlet of the fifth opening in step d is analyzed using an analysis device.

[0121] The procedure may also include one or both of the following steps:

[0122] - Switching the rotary valve to the fifth position and then conveying solvent through the filter cartridge by means of the pump operating in pump mode and on to the outlet of the seventh opening, so that material retained in the filter cartridge is transported to the outlet of the seventh opening (step f),

[0123] - Switching the rotary valve to the seventh position and then taking up solvent from the solvent supply system using the pump operating in suction mode (step g).

[0124] If necessary, the steps are to be executed in one of the following sequences: acbcd; acbced; bacd; baced; acbcgd; acbcged; bacgd; bacged; gacbcd; gacbced; acgbcd; acgbced; gbacd; gbaced.

[0125] If necessary, it is provided that step f is carried out after the completion of one sequence and before the start of a subsequent sequence.

[0126] Further features are described in the patent claims, the description of the exemplary embodiment, and the figures. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0127] Advantageous embodiments of the aspects described herein are explained in detail below. These are intended solely for illustrative purposes and do not restrict the scope of protection defined by the independent patent claims.

[0128] They show:

[0129] Fig. 1 shows a schematic representation of a first embodiment of a system with a rotary valve in a first position;

[0130] Fig. 2 shows a schematic representation of the first embodiment in a second position;

[0131] Fig. 3 shows a schematic representation of the first embodiment in a third position;

[0132] Fig. 4 shows a schematic representation of the first embodiment in a fourth position;

[0133] Fig. 5 shows a schematic representation of the first embodiment in a fifth position;

[0134] Fig. 6 shows a schematic representation of the first embodiment in a sixth position;

[0135] Fig. 7 shows a schematic representation of the first embodiment in a seventh position;

[0136] Fig. 8 shows a schematic representation of a second embodiment in a first position; and

[0137] Fig. 9 shows a schematic view of the basic structure of a rotary valve.

[0138] Unless otherwise indicated, the figures show the following features and components: stator 1, rotor 2, central axis 3, first opening 4-1, second opening 4-2, third opening 4-3, fourth opening 4-4, fifth opening 4-5, sixth opening 4-6, seventh opening 4-7, eighth opening 4-8, ninth opening 4-9, tenth opening 4-10, eleventh opening 4-11, twelfth opening 4-12, thirteenth opening 4-13, stator outer surface 5, stator inner surface 6, rotor inner surface 7, radial connection path 8-1, further

[0139] Connecting paths 8-2 and 8-3, drive shaft 9, drive unit 10, connecting line 11, filter cartridge 12, sample container 13, waste line 14, analyzer 15, pump 16, solvent supply system 17, circuit 18, first hexagon 19, second hexagon 20, sorbent container 21, frit 22, autosampler 23. 65204 / MB / -

[0140] University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0141] The system shown in Figures 1 to 7, according to a first embodiment, comprises a rotary valve whose rotor has three connecting paths 8-1, 8-2, 8-3. The stator has thirteen openings 4-1, 4-2, ..., 4-13, each of which has a corresponding connection.

[0142] The first opening 4-1 is located in the center of the rotary valve and the central axis runs through this first opening 4-1; therefore, when the rotor is rotated relative to the stator, the position of the first opening 4-1 remains unchanged.

[0143] The third to eighth openings 4-3, 4-4, ... , 4-8 form the vertices of a first regular hexagon 19, which is shown only in Fig. 1 for illustrative purposes. The center of this first hexagon 19 is the first opening 4-1 .

[0144] The second opening 4-2, as well as the ninth to thirteenth openings 4-9, 4-10, 4-11, 4-12, 4-13, also form the vertices of a regular hexagon, namely the second regular hexagon 20, which is shown only in Fig. 1 for illustrative purposes. The center of this second hexagon 20 is also formed by the first opening 4-1.

[0145] The first hexagon 19 and the second hexagon 20 are therefore concentric, with the vertices of the second hexagon 20 being rotated by about 30° relative to the vertices of the first hexagon 19.

[0146] The second opening 4-2 lies along the angle bisector of two lines, with the first opening 4-1 and the third opening 4-3 lying on the first of these lines, and the first opening 4-1 and the eighth opening 4-8 lying on the second of these lines. The ninth opening 4-9 lies along the angle bisector of two lines, with the first opening 4-1 and the seventh opening 4-7 lying on the first of these lines, and the first opening 4-1 and the eighth opening 4-8 lying on the second of these lines.

[0147] The radial connection path 8-1 runs on the inner surface of the rotor starting from the first opening 4-1 in a radial direction, the length of which is 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0148] 8-1 essentially corresponds to the distance between the first opening 4-1 and the third to eighth openings 4-3, 4-4, ... , 4-8. This allows the radial connection path to establish a fluid-conducting connection between the first opening 4-1 and all other openings 4-2, 4-3, ... , 4-13, whereby in every position the first opening 4-1 is always connected to only one other opening 4-2, 4-3, ... , 4-13.

[0149] The further connecting paths 8-2, 8-3, also referred to as the second connecting path 8-2 ​​and the third connecting path 8-3, form arcs of a circle 18 (illustrated in Fig. 1), the center of which is formed by the central axis or the first opening. The central angle α of these two arcs is approximately 62° in this example, but generally at least 60°, particularly between 60° and 79°, preferably between 71° and 79°. Thus, the further connecting paths 8-2, 8-3 have the length required to connect any two adjacent openings of the third to eighth openings 4-3, 4-4, ... , 4-8. The further connecting paths 8-2, 8-3 cannot connect more than two openings in any valve position, and they cannot establish a direct connection between the first opening and any of the third to eighth openings 4-3, 4-4, ... , 4-8.

[0150] Fig. 1 shows the rotary valve in the first position. Here, the radial connecting path 8-1 connects the first opening 4-1 with the second opening 4-2. The other connecting paths 8-2, 8-3 do not connect any openings to each other.

[0151] Fig. 2 shows the rotary valve in the second position. Here, the radial connection path 8-1 connects the first opening 4-1 with the eighth opening 4-8. The second connection path 8-2 ​​connects the third opening 4-3 and the fourth opening 4-4; this connection results from the geometry of the rotary valve and is not relevant to the intended functionality. The third connection path 8-3 connects the sixth opening 4-6 and the seventh opening 4-7.

[0152] Fig. 3 shows the rotary valve in the third position. Here, the radial connecting path 8-1 connects the first opening 4-1 with the fifth opening 4-5. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0153] Fig. 4 shows the rotary valve in the fourth position. Here, the radial connecting path 8-1 connects the first opening 4-1 with the fourth opening 4-4. The second connecting path 8-2 ​​connects the fifth opening 4-5 and the sixth opening 4-6. The third connecting path 8-3 connects the third opening 4-3 and the eighth opening 4-8.

[0154] Fig. 5 shows the rotary valve in the fifth position. Here, the radial connection path 8-1 connects the first opening 4-1 with the sixth opening 4-6. The second connection path 8-2 ​​connects the seventh opening 4-7 and the eighth opening 4-8. The third connection path 8-3 connects the fourth opening 4-4 ​​and the fifth opening 4-5, this connection resulting from the geometry of the rotary valve and not relevant to the intended functionality.

[0155] Fig. 6 shows the rotary valve in the sixth position. Here, the radial connecting path 8-1 connects the first opening 4-1 with the ninth opening 4-9. The other connecting paths 8-2, 8-3 do not connect any openings to each other.

[0156] Other positions of the rotary valve are not shown in the figures, namely:

[0157] - the seventh position, in which the first opening 4-1 and the tenth opening 4-10 are connected by the radial connecting path 8-1,

[0158] - the eighth position of the rotary valve, in which the first opening 4-1 and the seventh opening 4-7 are connected by the radial connecting path 8-1.

[0159] The system shown in Figures 1 to 6 has the following components in addition to the rotary valve:

[0160] - a bidirectional pump 16 connected to the connection of the first opening 4-1;

[0161] - a sample container 13 connected to the connection of the ninth opening 4-9;

[0162] - a connecting line 11 connecting the connection of the third opening 4-3 and the connection of the fourth opening 4-4 ​​;

[0163] - an analytical device 15 connected to the connection of the fifth opening 4-5, comprising a chromatographic column and a detection device; 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0164] - a line connecting the connection of the sixth opening 4-6 and the connection of the eighth opening 4-8, along which a filter cartridge 12 is arranged, comprising a sorbent receiving area and a frit 22;

[0165] - a waste pipe 14 connected to the connection of the seventh opening 4-7;

[0166] - a solvent supply system connected to the connection of the tenth opening 4-10 17.

[0167] An exemplary analysis method begins with the rotary valve in the first position according to Fig. 1. In this position, the bidirectional pump 16 is connected to the sorbent container 21 via a sufficiently long hose so that a suitable amount of suspension can be drawn in, but the sorbent does not enter the pump 16.

[0168] After the suction process is complete, the rotary valve is moved to the second position as shown in Fig. 2, and the sorbent suspension is discharged. The suspension flows through the radial connection path 8-1 to the outlet of the eighth opening 4-8 and from there through the filter cartridge 12. The sorbent material is retained by the frit 22, and the now particle-free liquid passes through the third connection path 8-3 to the waste line 14 and is disposed of. The sorbent is purified by the addition of a further quantity of solvent and prepared for sample collection.

[0169] The rotary valve is then moved to the sixth position as shown in Fig. 6 to draw in the sample. The liquid sample is drawn from the sample container 13 via the connection of the ninth opening 4-9 by the pump 16, which is operating in suction mode. The sample container 13 can be a single container, but an automated sample feed system can also be provided.

[0170] After the sample has been drawn from the sample container, the rotary valve is returned to the second position (Fig. 2). The pump 16 is operated in pump mode, so that the previously drawn sample is conveyed via the eighth opening 4-8 into the filter cartridge 12 and through the sorbent contained therein. The analytes of interest from the sample adhere to the sorbent, while the sample matrix passes through the 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0171] Filter cartridge 12 is flushed to the sixth opening 4-6 and via the third connecting path 8-3 further to the waste line 14.

[0172] At this point, sample preparation is complete and the system is ready for sample analysis. In this embodiment, the rotary valve moves to the seventh position, as illustrated in Fig. 7, and the pump 16 draws solvent from the solvent supply system 17.

[0173] In this embodiment, the chromatographic column of the analytical device 15 is operated under pressure. This can be achieved by moving the rotary valve to the third position after sample preparation is complete. In this position, the pump 16 is connected to the analytical device 15 via the first opening 4-1, the radial connection path 8-1, and the fifth opening 4-5. By operating the pump 16 in pump mode, the system, or rather the chromatographic column of the analytical device 15, can be pressurized.

[0174] The rotary valve is then moved to the fourth position (Fig. 4) to elute the sample from the filter cartridge 12. The switch from the seventh to the fourth position is preferably performed quickly to prevent a pressure drop. The tenth opening 4-10, which is passed over by the radial connecting path 8-1 during this switching process, is closed.

[0175] In the fourth position now occupied, the previously aspirated solvent is discharged again by operating pump 16 in pump mode and passed through the filter cartridge 12 via the fourth opening 4-4, the connecting line 11, the third opening 4-3, the third connecting path 8-3, and the eighth opening 4-8. If the elutropic strength of the solvent is sufficient, the analytes are eluted from the sorbent and introduced into the analyzer 15 via the sixth opening 4-6, the second connecting path 8-2, and the fifth opening 4-5.

[0176] After the analysis is complete, the system is ready for the next injection. The rotary valve is returned to the sixth position (Fig. 6), and the process described above, starting with the sample intake, begins again. This may involve a different sample than in the first run, for example, if sample container 13 was manually replaced or if sample container 13 is part of an automated sample introduction system.

[0177] If necessary, the lines can be pre-flushed with a sample. For this purpose, a quantity of sample can be drawn from the sample container 13 in the sixth position, after which the rotary valve is moved to the eighth position. By operating the pump 16 in pump mode, the previously drawn sample is conveyed via the radial connection path 8-1 through the seventh opening 4-7 to the waste line 14 and disposed of. The rotary valve is then returned to the sixth position, another sample is drawn, and this is then sent for analysis as described above.

[0178] After the analysis of a sample has been completed, the sorbent can be removed from the filter cartridge 12 (e.g. if it is not needed for the next analysis) or it can be replaced (e.g. if its performance is reduced).

[0179] For this purpose, the rotary valve is moved to the fifth position, as shown in Fig. 5, in which solvent is directed through the filter cartridge 12 via the sixth opening 4-6 towards the eighth opening 4-8. The sorbent is removed from the filter cartridge 12 by the solvent and fed to the waste line 14 via the seventh opening 4-7 and disposed of.

[0180] If no sorbent is required for the next analysis, the rotary valve can be moved directly to the third position to receive the sample. If refilling the filter cartridge 12 with sorbent is desired, begin by operating the rotary valve in the first position, as described above.

[0181] It should be noted that the eleventh to thirteenth openings 4-11, 4-12, 4-13 and the corresponding ports were not used in this embodiment. These are generally available for receiving other sorbents, samples, solvents, or air. However, these openings may be omitted in other embodiments. 65204 / MB / -

[0182] University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0183] In connection with this embodiment, it should be mentioned that solvent is introduced into the system by suction from the solvent supply system 17 with the rotary valve in the seventh position. This intermediate step is performed not only before the actual analysis begins, but also before all other steps in which solvent is pumped through the system.

[0184] In an alternative embodiment of the system, not described in detail here, this intermediate step can also be omitted (i.e., the rotary valve does not need to be moved to the seventh position). This is the case when the pump 16 is arranged between the solvent supply system 17 and the first opening 4-1. The pump can then obtain the solvent directly from the solvent supply system 17 without using the rotary valve.

[0185] Fig. 8 shows a schematic representation of a second embodiment of a rotary valve in a first position. Its construction largely corresponds to that of the first embodiment, with the following differences:

[0186] Only nine openings 4-1, 4-2, ..., 4-9 are provided. The other openings from the first embodiment are missing in this second embodiment.

[0187] Furthermore, an autosampler 23 is connected to the connection of the second opening 4-2, which is designed to selectively provide sorbent suspension, sample and solvent.

[0188] The method differs from that of the first embodiment in that the rotary valve cannot assume a sixth and seventh position, nor are these required. Instead of assuming these positions, the rotary valve is always moved to the first position when the sample is introduced, when the optional rinsing with sample solution takes place, and when solvent is added. The selection of which liquid is introduced into the system is based on the setting of the autosampler 23 and not on the position of the rotary valve. 65204 / MB / -

[0189] University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0190] Apart from these differences, the rotary valve, the system and the method of the second embodiment are identical to those of the first embodiment.

[0191] Fig. 9 shows a schematic side view of a rotary valve as it can be used in this embodiment.

[0192] The rotary valve comprises the stator 1 and the rotor 2. The stator 1 has an inner surface 6 and an outer surface 5, with openings (not shown) arranged on the inner surface 6 and corresponding connections (not shown) on the outer surface 5. The rotor 2 has an inner surface 7 on which connecting channels (not shown) are arranged. The inner surface 6 of the stator and the inner surface 7 of the rotor are in direct contact with each other.

[0193] The rotor 2 is rotatable relative to the stator 1 about the central axis 3, with the rotation being effected by the drive shaft 9 and the drive unit 10. In this embodiment, the drive unit 10 is a motor; however, it could also be, among other things, a hydraulic drive.

[0194] Details regarding the rotary valve can be found in the rest of the description.

[0195] The rotary valve described herein offers a multitude of advantages, which, apart from the improvement of chemical analysis, also relate to mechanical aspects.

[0196] Advantageous mechanical aspects include:

[0197] - When selecting the inner openings (i.e., the second, ninth, tenth, eleventh, twelfth, or thirteenth opening) and establishing a connection between one of these openings and the first opening 4-1 via the radial connection path 8-1, no undesired flow can occur, since the further connection paths 8-2 and 8-3 do not connect any openings to each other. 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT)

[0198] - The nesting of the connections enables the production of a rotary valve with a small footprint and therefore high pressure tolerance.

[0199] Advantageous aspects of chemical analysis include:

[0200] - Any quantity of sorbent can be packed into the filter cartridge 12, thereby bypassing sorbent compaction and irreversible sorption of matrix components, and enabling the use of sorbent in large quantities (mg range).

[0201] - In one step, the sample can be passed through the filter cartridge 12 loaded with sorbents, the analytes can be captured and the matrix washed out.

[0202] - the filter cartridge 12 loaded with sorbents can be inserted into the stream of the chromatographic flow.

[0203] - The sorbent can be eluted with the chromatographic mobile phases, resulting in very high amplification factors.

[0204] - the sorbent can be unpacked with positive pressure.

Claims

65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT) Patent claims 1. Rotary valve with a stator (1 ) and a rotor (2), wherein the stator (1 ) and rotor (2) are rotatable relative to each other about a central axis (3), - wherein the stator (1 ) has a plurality of openings (4) on an inner stator surface (6), each of which has a channel extending to a corresponding connection on an outer stator surface (5), - wherein the rotor (2) has several connecting paths (8-1 , 8-2, 8-3), - wherein the stator inner surface (6) and the rotor inner surface (7) are in fluid-tight contact, characterized in that - that a first to eighth opening (4-1 , 4-2, ... , 4- 8) is provided on the inner surface (6) of the stator, wherein the central axis (3) passes through the first opening (4-1 ), - that a radial connection path (8-1 ) is provided which runs in a radial direction to the central axis (3), - that at least two further connecting routes (8-2, 8-3) are planned, - and that: o in a first position of the rotary valve: the first opening (4-1 ) and the second opening (4-2) are connected by the radial connecting path (8-1 ), o in a second position of the rotary valve: the first opening (4-1 ) and the eighth opening (4-8) are connected by the radial connecting path (8-1 ); and the sixth opening (4-6) and the seventh opening (4-7) are connected by a further connecting path (8-3), o in a third position of the rotary valve: the first opening (4-1 ) and the fifth opening (4-5) are connected by the radial connecting path (8-1 ), o in a fourth position of the rotary valve: the first opening (4-1 ) and the fourth opening (4-4) are connected by the radial connecting path (8-1 ); the third opening (4-3) and the eighth opening (4-8) are connected by a further connecting passage (8-3); and the fifth opening 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT) (4-7) and the sixth opening (4-6) are connected by a further connecting path (8-2), or in a fifth position of the rotary valve: the first opening (4-1) and the sixth opening (4-6) are connected by the radial connecting path (8-1); and the seventh opening (4-7) and the eighth opening (4-8) are connected by a further connecting path (8-2).

2. Rotary valve according to claim 1, characterized in that the further connecting paths (8-2, 8-3) do not establish a connection between openings (4) in the first position of the rotary valve.

3. Rotary valve according to claim 1 or 2, characterized in that a ninth opening (4-9) is further provided, that in a sixth position of the rotary valve the first opening (4-1 ) and the ninth opening (4-9) are connected by the radial connecting path (8-1 ), and that optionally the further connecting paths (8-2, 8-3) do not establish a connection between openings (4) in the sixth position of the rotary valve.

4. Rotary valve according to one of claims 1 to 3, characterized in that - in a seventh position of the rotary valve: the first opening (4-1 ) and a tenth opening (4-10) are connected by the radial connecting path (8-1 ), and / or that in an eighth position of the rotary valve: the first opening (4-1 ) and the seventh opening (4-7) are connected by the radial connecting path (8-1 ).

5. Rotary valve according to one of claims 1 to 4, characterized in that, - that the further connecting paths (8-2, 8-3) have the form of circular arcs, with the center of the corresponding circle (18) being formed by the first opening (4-1), if applicable, or - that the further connecting paths (8-2, 8-3) are linear and may run tangentially with respect to a circle whose center is formed by the first opening (4-1 ). 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT) 6. Rotary valve according to claim 5, characterized in that the central angle (a) of the circular arcs is at least 60°, in particular between 60° and 79°, preferably between 71° and 79°.

7. Rotary valve according to one of claims 1 to 6, characterized in that two, three or more further connecting paths (8-2, 8-3) are provided.

8. Rotary valve according to one of claims 1 to 7, characterized in that the third to eighth openings (4-3, 4-4, ... , 4-8) are located at the vertices of a first regular hexagon (19) whose center point is formed by the first opening (4-1 ).

9. Rotary valve according to one of claims 1 to 8, characterized in that the length of the radial connection path (8-1 ) corresponds essentially to the distance between the first opening (4-1 ) and the third to eighth openings (4-3, 4-4, ... , 4-8).

10. Rotary valve according to one of claims 1 to 9, characterized in that the stator inner surface (6) and the rotor inner surface (7) are essentially planar planes, or that the rotor (2) has a frustoconical section, the smaller base area and the outer surface of which form the rotor inner surface (7), or that the rotor (2) has a spherical segment-shaped section, the outer surface of which forms the rotor inner surface (7).

11. System for the preparation and, if necessary, analysis of a sample containing an analytical material in a liquid medium, the system comprising: - a rotary valve according to one of claims 1 to 10, - a connecting line (11) arranged between the connection of the third opening (4-3) and the connection of the fourth opening (4-4) , - a filter cartridge (12) arranged between the connection of the sixth opening (4-6) and the connection of the eighth opening (4-8), - a bidirectional pump (16) connected to the connection of the first opening (4-1), which has a suction mode and a pumping mode, and 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT) - a supply system connected to the connection of the second opening (4-2), in particular an autosampler (23), wherein the liquid supply system is configured to supply sample, sorbent material suspension and, if applicable, solvent.

12. System for the preparation and, if necessary, analysis of a sample containing an analytical material in a liquid medium, the system comprising: - a rotary valve according to one of claims 3 to 10, - a connecting line (11) arranged between the connection of the third opening (4-3) and the connection of the fourth opening (4-4) , - a filter cartridge (12) arranged between the connection of the sixth opening (4-6) and the connection of the eighth opening (4-8), - a bidirectional pump (16) connected to the connection of the first opening (4-1), which has a suction mode and a pumping mode, - a sample container (13) connected to the connection of the ninth opening (4-9) for receiving the sample, and - a sorbent container (21) connected to the connection of the second opening (4-2) for receiving sorbent material suspension.

13. System according to claim 11 or 12, characterized in that the filter cartridge (12) has a retention means, in particular a filter frit, and a sorbent receiving area, wherein the sorbent receiving area is in particular arranged between the retention means and the connection of the eighth opening (4-8).

14. System according to one of claims 11 to 13, characterized in that an analysis device (15) is connected to the connection of the fifth opening (4-5), and / or that a waste line (14) is connected to the connection of the seventh opening (4-7).

15. System according to one of claims 11 to 14, characterized in that the system further comprises a solvent supply system (17) connected to the connection of the tenth opening (4-10) for providing a solvent, 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT) and / or that the system further comprises a solvent supply system (17) connected to the pump (16) for the provision of a solvent, and / or that a solvent supply system (17) is coupled to the liquid supply system, in particular to the autosampler (23).

16. A method for preparing and optionally analyzing a sample using a system according to any one of claims 11 to 15, the method comprising the following steps: a. switching the rotary valve to the first position and subsequently taking up sorbent material suspension, in particular from the sorbent container (21) or from the liquid supply system, b. switching the rotary valve to the first position or leaving the rotary valve in the first position and subsequently taking up sample from the liquid supply system by means of the pump (16) operated in suction mode, or switching the rotary valve to the sixth position and subsequently taking up sample from the sample container (13) by means of the pump (16) operated in suction mode, c.Switching the rotary valve to the second position and then conveying the collected material, in particular sorbent material suspension, sample and / or solvent, by means of the pump (16) operated in pump mode to the outlet of the seventh opening (4-7) and through the filter cartridge (12), whereby the sorbent material is retained in the filter cartridge (12), i.e. switching the rotary valve to the fourth position and then conveying solvent through the filter cartridge (12) by means of the pump (16) operated in pump mode and further to the outlet of the fifth opening (4-5).

17. Method according to claim 16, characterized in that the method further comprises the following step: e. Switching the rotary valve to the third position and subsequently conveying solvent by means of the pump (16) operated in pump mode to the outlet of the fifth opening (4-5). 65204 / MB / - University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Straße 33, 1180 Vienna (AT) 18. Method according to claim 16 or 17, characterized in that the solution exiting from the outlet of the fifth opening (4-5) in step (d) is analyzed by means of an analysis device (15).

19. Method according to one of claims 16 to 18, characterized in that the method further comprises one or both of the following steps: f. Switching the rotary valve to the fifth position and subsequently conveying solvent through the filter cartridge (12) by means of the pump (16) operated in pump mode and further to the outlet of the seventh opening (4-7), so that material retained in the filter cartridge (12) is transported to the outlet of the seventh opening (4-7), g. Switching the rotary valve to the seventh position and subsequently taking up solvent from the solvent supply system (17) by means of the pump (16) operated in suction mode.

20. Method according to one of claims 16 to 19, characterized in that, - that the steps are executed in one of the following sequences: acb-cd; acbced; bacd; baced; acbcgd; acbcged; bacgd; bac-ged; gacbcd; gacbced; acgbcd; acgbced; gbacd; gbac-ed; - and that, if necessary, step (f) is carried out after the completion of one sequence and before the start of a subsequent sequence.

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