VALVE ASSEMBLY

Abstract

The present invention relates to a valve assembly, comprising a valve chamber, accesses to the valve chamber, the accesses including a first access and a second access, and a movable sealing body assembly comprising at least one sealing portion, wherein at least a portion of the sealing body assembly is magnetic, and wherein at least a portion of the sealing body assembly comprising the at least one sealing portion is located within the valve chamber. Further, the valve assembly comprises at least one sealing surface, wherein each of the at least one sealing surface is configured to complement one of the at least one sealing portion, and wherein each sealing surface comprises an orifice fluidly connected to one of the accesses. The valve assembly further comprises a force unit configured to exert a magnetic force on the magnetic portion of the movable sealing body assembly and is configured to assume at least two configurations, wherein in a first configuration, the first access is sealed, and wherein in a second configuration, the first access is fluidly connected to the second access. Further, the present invention relates to a pump system, as well as a use and manufacturing method of a valve assembly according got the present invention.

Claims

1. A valve assembly, comprising a valve chamber; accesses to the valve chamber, the accesses including a first access and a second access; a movable sealing body assembly comprising at least one sealing portion, wherein at least a portion of the sealing body assembly is magnetic, and wherein at least a portion of the sealing body assembly comprising the at least one sealing portion is located within the valve chamber; at least one sealing surface, wherein each of the at least one sealing surface is configured to complement one of the at least one sealing portion, and wherein each sealing surface comprises an orifice fluidly connected to one of the accesses; and a force unit configured to exert a magnetic force on the magnetic portion of the movable sealing body assembly, wherein the valve assembly is configured to assume at least two configurations, wherein in a first configuration, the first access is sealed, and wherein in a second configuration, the first access is fluidly connected to the second access.

2. The valve assembly according to claim 1, wherein the sealing surface and the sealing portion configured to complement said sealing surface are configured to form a leak-tight sealing interface when pressed together, which seals the orifice comprised by the sealing surface.

3. The valve assembly according to claim 1, wherein a hardness of the at least one sealing portion is different to a hardness of the at least one sealing surface.

4. The valve assembly according to claim 1, wherein the force unit is configured to press the sealing portion against the complementary sealing surface by exerting the force on the magnetic portion.

5. The valve assembly according to claim 1, wherein the force unit is configured to move the sealing body assembly and/or to actively change the configuration assumed by the valve assembly by exerting the force on the magnetic portion at least for any differential pressure between any of the accesses to the valve chamber that does not exceed a differential pressure threshold, wherein the differential pressure threshold is at least 20 bar, preferably at least 50 bar, more preferably at least 100 bar.

6. The valve assembly according to claim 1, wherein the force unit comprises at least one a permanent magnet and an actuator configured to provide a rotational or linear motion, wherein the actuator is configured to provide a linear or rotational displacement to the at least one permanent magnet connected thereto.

7. The valve assembly according to claim 1, wherein the force unit comprises at least one solenoid.

8. The valve assembly according to claim 1, wherein the movable sealing body assembly is not firmly attached to any other portion of the valve assembly.

9. A pump system configured to provide a flow of fluid, wherein the system comprises at least one pump unit; an inlet valve configured to control a fluid flow at an inlet of at least one of the at least one pump unit; and an outlet valve configured to control a fluid flow at an outlet of at least one of the at least one pump unit, wherein at least one of the inlet valve and the outlet valve is a valve assembly according to claim 1.

10. The pump system according claim 9, wherein the pump system is configured for reversing the flow through the pump system to purge the system.

11. Manufacturing method for manufacturing a valve assembly according to claim 1, wherein the manufacturing comprises calibrating the at least one sealing portion and/or the complementary sealing surface to provide an accurately fitting sealing contour.

12. Manufacturing method according to claim 11, wherein the at least one sealing portion and the complementary sealing surface comprise different degrees of hardness, and wherein the step of calibrating comprises applying a hydraulic pressure configured to press the sealing portion and the sealing surface together while the valve assembly is assembled.

Description

[0224] Embodiments of the present invention will now be described with reference to the accompanying drawings. These embodiments should only exemplify, but not limit, the present invention.

[0225] FIGS. 1 and 2 depict a valve assembly according to embodiments of the present invention;

[0226] FIGS. 3 and 4 depict another valve assembly according to embodiments of the present invention;

[0227] FIG. 5 depicts a further valve assembly according to embodiments of the present invention;

[0228] FIG. 6 depicts a further valve assembly according to embodiments of the present invention; and

[0229] FIGS. 7A and 7B depict a still further valve assembly according to embodiments of the present invention.

[0230] It is noted that not all the drawings carry all the reference signs. Instead, in some of the drawings, some of the reference signs have been omitted for the sake of brevity and simplicity of the illustration.

[0231] In one embodiment, the invention relates to a valve assembly 1. Generally, the valve assembly 1 comprises a valve chamber 11, a plurality of accesses 121, 122 to the valve chamber 11, a movable sealing body assembly 13, at least one sealing surface 14 and a force unit 15.

[0232] The movable sealing body assembly 13 comprises at least one sealing portion 131 and at least a portion of the sealing body assembly 13 comprising the at least one sealing portion 131 is located within the valve chamber 11. That is, in some embodiments, the sealing body assembly 13 may be entirely located within the valve chamber 11, while in other embodiments only a portion of the sealing body assembly 13 may be located within the valve chamber 11. At least the portion of the sealing body assembly 13 comprising the at least one sealing portion 131 may be located within the valve chamber 11.

[0233] The valve chamber 11 may comprise a valve chamber volume. That is, the valve chamber may define a valve chamber volume, which may also be referred to as chamber volume. The chamber volume may be smaller than 500 μl, preferably smaller than 100 μl, more preferably smaller than 50 μl.

[0234] Consequently, the phrase “located within the valve chamber” refers to an object, e.g. part or portion, which is placed within the valve chamber volume. Thus, at least a portion of the movable sealing body assembly 13 is located within the valve chamber volume and in particular the at least one sealing portion 131 is located within the valve chamber volume.

[0235] Particularly, the at least a portion of the sealing body assembly 13 located within the chamber volume is located such that it is movable within the valve chamber 11. That is, the at least a portion of the sealing body assembly 13 may not fill the chamber volume completely. In other words, the at least a portion of the sealing body assembly 13 may be movable within the valve chamber 11, e.g., along at least one axis. However, the flushed volume of the valve chamber 11, i.e. the volume of the valve chamber, which is not filled with a portion of the sealing body assembly, may advantageously be minimized. In other words, the dead volume of the vale chamber 11 may advantageously be small, e.g. compared to utilizing a double check valve at the outlet of a pump.

[0236] Further, the sealing body assembly 13 may comprise a magnetic portion 132, i.e. at least a portion of the sealing body assembly 13 may be magnetic. The magnetic portion 132 may for example comprise a ferrite or a ferromagnetic material, such as an iron, cobalt and/or nickel alloys (e.g. alnico) or Nd.sub.2Fe.sub.14B (Neodymium magnet). Thus, generally the magnetic portion may comprise a soft- or a hard-magnetic material. Consequently, it may form a permanent or a non-permanent magnet. It will be understood that hard magnetic materials may be permanently magnetic and soft magnetic materials may be easily magnetised and demagnetised. In some embodiments, the sealing body assembly may preferably comprise a hard-magnetic material.

[0237] Each of the at least one sealing surface 14 may be configured to complement one of the at least one sealing portion 131. Further, each of the at least one sealing surface 14 may comprise an orifice 141 fluidly connected to one of the accesses 121, 122, 123 to the valve chamber. In other words, the at least one sealing surface 14 may be configured such that it may form a leak-tight connection with the corresponding sealing portion 131 of the sealing body assembly 13 and thus substantially prevent flow of a fluid through the orifice 141 of the sealing surface 14. That is, the sealing surface 14 may for example be formed to accommodate at least a portion of the corresponding sealing portion 131 to form a leak-tight connection and thus block the orifice 141 comprised by the sealing surface 14.

[0238] The phrase “forming a leak-tight connection” may refer to providing a sealed connection. Generally, the sealing surface 14 and the sealing portion 131 may form a sealing interface when in contact with each other and said sealing interface may be such that substantially no fluid may leak through. Thus, the sealing surface 14 and the sealing portion 131 may form a leak-tight connection. However, it will be understood, that the leak-tight connection is generally substantially leak-tight. That is, it may still comprise a residual leak rate, which may be less than or equal to 100 nl/min, preferably less than or equal to 50 nl/min, more preferably less than or equal to 5 nl/min.

[0239] Generally, it may be desirable to minimize the area of the sealing interface, i.e. the projected surface between the sealing portion 131 and the sealing surface 14.

[0240] In order to ensure a leak-tight connection between the sealing portion 131 and the sealing surface 14, the sealing portion 131 and the sealing surface 14 may be calibrated with respect to each other, e.g. as part of the manufacturing process. In other words, there may be a one-off hydraulic calibration of the sealing surface 14 and/or the sealing portion 131, e.g. during production. The calibration may for example comprise pressing a geometry that is at least similar to the sealing portion 131 into the sealing surface 14 either by means of a pre-press tool or for example by applying a hydraulic pressure that presses the sealing portion 131 into the sealing surface 14, when in an assembled state. Therefore, preferably either the sealing surface 14 or the sealing portion 131 may comprise a softer material than the respective other portion, such that during the calibration the softer material may be formed to provide a leak-tight sealing interface between the sealing portion 131 and the sealing surface 14. In other words, the hardness of the sealing portion 131 may be different compared to the hardness of the sealing surface. Thus, they may be calibrated, e.g. moulded, with respect to each other by applying a hydraulic pressure that presses them together, e.g. when in an assembled state, at which point the harder portion (i.e. the sealing portion 131 or the sealing surface 14) may deform the respective other portion, such that they form a calibrated sealing interface. In other words, the soft sealing portion 131 or respectively sealing surface 14 is calibrated, e.g. moulded, by the hard sealing surface 14 or respectively sealing portion 131.

[0241] The force unit 15 may generally be configured to exert a force on the magnetic portion 132 of the movable sealing body assembly 13. For example, the force unit 15 may force the sealing body assembly 13, and thus the sealing portion 131, towards one of the at least one sealing surface 14 to block the orifice 141 comprised by said sealing surface 14. Similarly, it may for example exert a force in the opposite direction, thus preventing the sealing portion 131 from blocking the respective orifice 141 in the corresponding sealing surface 14. In other words, the force unit 15 may exert a force on the magnetic portion 132 of the sealing body assembly 13, which may enable active opening and closing of at least one access 121, 122, 123 to the valve chamber 11. This may generally provide certain advantages: it may allow for faster switching than with purely gravity or liquid flow driven check valves, i.e. passive check valves. Furthermore, such a valve assembly 1 may even open against a pressure that would otherwise keep the sealing portion 131 pressed against the respective sealing surface 14 such that the orifice 141 remains blocked. Particularly, the described valve assembly 1 may allow to actively change the configuration assumed by the valve assembly, which may be more reliable than for passive check valves, particularly in the presence of gluing and/or setting effects.

[0242] Generally, the valve assembly 1 may be configured to assume at least two configurations, wherein in the first configuration I, a first access 121 is sealed and wherein in the second configuration II the first access 121 is fluidly connected to a second access 122. In other words, the valve assembly 1 may assume a first configuration I wherein a flow path between the first access 121 and the second access 122 is blocked and a second configuration II, wherein a fluid may flow between the first access 121 and the second access 122. Thus, the first configuration I may also be referred to as closed configuration and the second configuration II may be referred to as open configuration. In the open configuration a fluid may in some embodiments flow in any direction, i.e. from the first access 121 to the second access 122 or vice versa.

[0243] Reference will now be made to FIG. 1, which schematically depicts an exemplary embodiment of a valve assembly 1 according to the present invention. In particular, an exemplary 2/1-way valve according to the present invention is shown. That is, a valve with 2 fluidic connections (accesses 121, 122) and 1 way of connecting these two.

[0244] The valve assembly 1 comprises a valve chamber 11, which may for example be formed by a chamber body 111. The chamber body 111 or at least a portion thereof may be at least substantially non-ferromagnetic. That is, it may preferably be made from non-ferromagnetic material, e.g. titanium, PEEK or MP35N. It may also be possible to use PEEK within another material. That is, the chamber body may for example be made of stainless steel or another material and subsequently be injected with PEEK, such that an inner surface defining the chamber volume would for example be formed by PEEK. However, the term “substantially” is meant to include also very weakly ferromagnetic materials, which may not restrict the functionality of the valve assembly. In particular, materials may qualify as weakly ferromagnetic if they only experience negligible forces in the magnetic fields provided by the force unit 15 in comparison to the magnetic portion 132.

[0245] The chamber body 111 may comprise at least one opening through which it may for example receive the at least a portion of the sealing body assembly 13 that is located within the valve chamber 11. The opening may be fitted with a chamber seal 112. For example, once the at least a portion of the sealing body assembly 13 is placed within the valve chamber 11, each of the at least one opening may be fitted with a chamber seal 112. The chamber seal 112 may generally be designed to withstand typical pressures of applications in HPLC, that is the chamber seal 112 may withstand static pressures of at least 50 bar, preferably at least 100 bar, more preferably at least 400 bar, further preferably 800 bar.

[0246] The depicted embodiment comprises two accesses 121, 122 to the valve chamber 11. The first access 121 is provided by a channel through the chamber seal 112, while the second access is provided by a channel through the chamber body 111. Thus, the depicted valve assembly comprises two fluidic connections which may be fluidly connected through the valve chamber 11. However, it will be understood that for example also the first access 121 may be provided by a channel through the chamber body 111 and/or the second access 122 may be provided through the chamber seal 112. Generally, each access may be fluidly connected to a socket configured to receive a respective fluidic connector, allowing to directly connect the access to a respective capillary.

[0247] Furthermore, the valve chamber 11 comprises the movable sealing body assembly 13, which comprises a magnetic portion 132. The magnetic portion 132 may for example be completely or partially surrounded by an exterior portion of the sealing body assembly 13. That is, generally it may be comprised by one or more other portions of the sealing body assembly 13, such that it cannot get into contact with any liquid within the valve chamber 11. Furthermore, the sealing body assembly comprises a sealing portion 131, which may be designed to be accommodated by a complementary sealing surface 14 which may surround the channel of the first access 121. That is, the sealing portion 131 and the sealing surface 14 may be designed such that they can form a leak-tight connection and thus block a fluid flow through the first access 121.

[0248] In the depicted embodiment in FIG. 1, the sealing portion 131 of the sealing body assembly 13 is a sphere 131 which is attached to the remaining sealing body assembly 13. However, the sealing portion 131 may also assume different shapes and/or be integrally formed with the remaining sealing body assembly 13.

[0249] The sealing surface 14 may for example be comprised by the chamber seal 112 and designed such that the orifice 141 comprised by the sealing surface 14 is fluidly connected to the first access 121. The sealing surface 14 may be shaped to accommodate at least part of the sealing portion 131. In other words, it may be complementary to the sealing portion 131. Thus, the sealing portion 131 and the sealing surface 14 may provide a leak-tight connection when pressed onto each other. In some embodiments, the hardness of the sealing portion 131 and the sealing surface 14 may be different to allow for a calibration, e.g. by applying a high pressure, which may press the sealing portion 131 into the sealing surface 14 when in an assembled state.

[0250] Generally, the movable sealing body assembly 13 may preferably be moved along a central axis A1 of the valve chamber 11. The central axis A1 may run centrally through two opposing sides of the valve chamber 11 and preferably in the direction of its largest extent. That is, the central axis A1 may run through the centre of two opposing sides of the valve chamber 11, which may preferably be oriented such that the central axis A1 runs in the direction of the largest extent of the valve chamber 11. Preferably, the sealing portion 131 and the sealing surface 14 may both lie on the central axis A1. Generally, the sealing portion 131 and the sealing surface 14, and particularly the orifice 141 comprised thereby, may be aligned such that the sealing portions 131 may be moved between a position in which the sealing portion 131 and the sealing surface 14 form a leak-tight connection, blocking the orifice 141 comprised by the sealing surface 14 and a position wherein the sealing portion 131 is not in contact with the sealing surface 14 such that the orifice is fluidly connected to the chamber volume. It will be understood that the sealing portion 131 and the respective sealing surface 14 may preferably be in alignment, such that the sealing portion 131 may block the orifice 141 comprised by the sealing surface 14 in a sealing manner. Consequently, the sealing surface 14 and the sealing portion 131 may lie on the central axis A1 along which the movable sealing body assembly 13 may preferably be moved. In some embodiments, the valve chamber 11 may be rotationally symmetric around the central axis A1. Generally, if a portion is said “to lie on the axis”, this refers to the geometrical centre of said portion coinciding with the axis.

[0251] The second access 122 to the valve chamber 11 may be oriented such that it may not be blocked by the movable sealing body assembly 13. Therefore, the valve assembly 1 may in principle be similar to a passive check valve, wherein the first access 121 would be the inlet and the second access 122 would be the outlet. That is, generally, the valve assembly 1 provides a functionality similar to a passive check valve. However, the valve assembly 1 further comprises a force unit 15, which may actively exert a force on the sealing body assembly 13. By setting this force, one may for example determine at which pressure differential the valve opens.

[0252] In particular, the force unit 15 may exert a magnetic force on the magnetic portion 132 of the sealing body assembly 13, which may for example suffice to move the sealing body assembly 13. Thus, the force unit 15 may actively apply a force and for example, move the sealing body assembly 13 and particularly the sealing portion 131 towards, or away from, the sealing surface 14. Preferably, the force unit 15 may move the movable sealing body assembly 13 along the central axis A1, that is, in a direction parallel (or identical) to the central axis A1. The force unit 15 may therefore at least aid with changing the configuration the valve assembly 1 may assume, e.g. open or closed.

[0253] For example, the force unit 15 may comprise a permanent annular magnet 151, such as a ring magnet 151, which may be fitted around the valve chamber 11 and/or the chamber body 113. In other words, the valve chamber 11 may pass through the central opening of the annular magnet 151. Further, the annular magnet 151 may be movable with respect to the valve chamber 11. Preferably, the space between the inner surface of the annular magnet 1511, i.e. the surface within the opening, and an outer surface of the chamber body 113 is minimized, while maintaining enough space to allow for a relative movement of the annular magnet 151 to the valve chamber 11. This may be advantageous for minimizing the overall size of the valve assembly 1, as well as for providing a strong and homogenous magnetic field around the central axis A1 of the valve chamber 11, which may preferably run through the centre of the annular magnet 151.

[0254] The annular magnet 151 may comprise an axial magnetization direction along its rotational symmetry axis. That is, in the centre of the annular magnet, the magnetic field may be oriented along the axis around which the annular magnet is rotationally symmetric, i.e. the rotational symmetry axis. In other words, the magnetic field in the centre of the annular magnet may be oriented along the rotational symmetry axis of the annular magnet 151, i.e. perpendicular to the diameter of the annular magnet 151. Thus, the magnetization direction of the annular magnet 151 may preferably coincide with the central axis A1. Further, the central axis A1 may coincide with the rotational symmetry axis of the annular magnet 151.

[0255] The annular magnet 151 may either exert a repulsive or an attractive magnetic force onto the magnetic portion 132 of the sealing body assembly 13. More particularly, the magnetic portion 132 may generally be driven towards a relative position with respect to the annular magnet 151 that leads to an equilibrium between repulsion and attraction, which corresponds to a force equilibrium. Thus, by moving the annular magnet 151, the sealing body assembly 13 may be moved and particularly the sealing portion 131 may be forced towards (or away from) the sealing surface 14. The direction of the force directly depends on the direction of the magnetic field and thus on the orientation of the magnetic poles of the annular magnet 151, as well as on the orientation and position of the magnetic portion 132 relative to the annular magnet 151. Therefore, the annular magnet 151, and thus the force unit 15, may advantageously allow for exerting a force onto the sealing body assembly 13 without the need of a mechanical link therebetween, i.e. contactless.

[0256] For example, in the embodiment depicted in FIG. 1, the annular magnet 151 may be oriented such that the magnetic field attracts the magnetic portion 132 of the sealing body assembly 13. Therefore, the resulting magnetic force may push the sealing body assembly 13 towards the sealing surface 14. Consequently, the sealing portion 131 of the sealing body assembly 13 may be received by and pressed into the sealing surface to form a leak-tight connection. Thus, the fluidic connection between the valve chamber 11 and the first access 121 may be blocked and the valve may assume the first (closed) configuration I.

[0257] The valve assembly 1 may be configured such that the closed position can be maintained for a pressure difference between the first access 121 and the valve chamber 11 of up to a differential pressure threshold of at least 20 bar, preferably at least 50 bar, more preferably at least 100 bar, wherein the higher pressure is present at the first access 121. It will be understood by the person skilled in the art that if the higher pressure is present in the valve chamber 11, e.g. by a pressurized fluid supplied at the second access 122, the valve assembly 1 may generally stay in the closed configuration, similarly to a passive check valve. However, if a fluid flow from the second access 122 to the first access 121 is desirable, the force unit 15 may apply a force to move the sealing body assembly 13 away from the sealing surface 14. For example, the annular magnet 151 may be moved away from the chamber seal 112 (in negative x-direction), forcing the sealing body assembly 131 away from the sealing surface 14. The valve assembly 1 may be configured such that the valve assembly 1 can be moved into the second (open) configuration II by means of the force unit 15 provided the pressure difference does not exceed the differential pressure threshold, wherein in this moment the higher pressure is present in the valve chamber 11. This may be advantageous for purging a pump the valve assembly may be fitted to.

[0258] Generally, it will be understood that when reference is made to a pressure difference, e.g. between an access and the valve chamber or two accesses, the pressure difference of the fluids comprised by (or supplied to) these portions is meant.

[0259] That is, generally the valve may operate similar to a passive check valve, wherein the valve assembly may change its configuration based on the pressure difference between the first access 121 and the second access 122. However, the threshold for the pressure difference at which the configuration may be changed is altered by the magnetic force acting on the movable sealing body 13. That is, while for a passive check valve the presence of a pressure difference may already suffice to change the configuration of the valve, the pressure difference needs to be high enough to provide a force higher than the magnetic force exerted on the movable portion 13 to change the configuration. In other words, the valve may be magnetically preloaded (similarly to a passive check valve preloaded by means of a spring). Such a valve may for example advantageously be used as pump discharge valve. Similarly, the valve may also change its configuration prior to reaching the pressure that would be necessary to open a passive check valve, that is as soon as the differential pressure is within the differential pressure threshold.

[0260] That is, the force unit may support the opening and closing of the valve assembly in said conditions by providing a magnetic force that pushes the movable sealing body assembly in the desired direction. However, in addition the force unit may actively open and close the valve also against a pressure difference of at least up to the differential pressure threshold. Thus, the valve may stay closed even if the higher pressure is present at the first access and similarly it may be opened even if the higher pressure is present in the valve chamber 11, provided that the pressure difference is below the limit specified above.

[0261] In other words, a valve assembly according to the present invention may advantageously allow active switching at high pressure, provided that the differential pressure does not exceed the differential pressure threshold. Thus, a reversal of the flow may also be possible at high system pressures. For example, switching at 800 bar and a differential pressure of 50 bar has been performed with a valve according to the present invention for 100,000 switching cycles, further showing the durability of the design.

[0262] Therefore, a valve according to embodiments of the present invention may allow for pre-compression of a fluid even above the pressure level of the valve chamber, e.g. prior to injection. That is, due to the possibility to actively prevent opening of the valve at least up to the differential pressure threshold, a fluid may be brought up to a pressure that is higher than the pressure within the valve chamber, which may for example allow for precise injection of a plug and/or prevent any backflow when the valve is opening. However, it will be understood that the valve may similarly be opened prior to reaching the pressure of the valve chamber, as long as the pressure difference is within the pressure difference threshold.

[0263] The force unit 15 is discussed in more detail with respect to FIG. 2. The force unit 15 may comprise a permanent annular magnet 151, an actuator 152 and a coupling unit 153. The actuator 152 may be configured to provide a linear motion which may be transmitted to the annular magnet 151 via a coupling unit 153. Generally, the linear motion provided by the actuator 152 may be coupled to the annular magnet 151 such that the annular magnet 151 can be moved back and forth with respect to the valve chamber 11, i.e. along an axis running through the valve chamber 11 in x-direction. Preferably it may be moved along the central axis A1 on which the sealing portion 131 and the sealing surface 14 preferably lie. For example, the actuator 152 may be a linear solenoid, a lifting solenoid or a linear motor.

[0264] In other words, the actuator 152 may transform an electrical signal into a mechanical motion, which may be transferred to the annular magnet 151 by means of a coupling unit 153. When the annular magnet 151 is moved such that its position changes relative to the magnetic portion 132 of the movable sealing body assembly 13, a magnetic force may be exerted onto the movable sealing body assembly 13, which may result in a movement of the magnetic sealing body assembly 13 or in a biasing thereof, i.e. the sealing portion 131 may be biased, e.g. pressed, against the sealing surface 14.

[0265] The guidance of the annular magnet 151, which may be moved relative to the valve chamber by means of the actuator 152, may be provided for example through the interaction of the inner surface of the annular magnet 1511 and the outer surface of the chamber body 113 and/or by the actuator 152 and/or coupling unit 153 connected to the annular magnet.

[0266] In other words, active displacement of the outer annular magnet 151 may be provided by a basic actuator 152, e.g. an electromagnetic lifting solenoid, which can easily be coupled to the annular magnet 151. The coupling unit 153 may transmit a push and/or pull motion which may depend on how the active check valve functions, e.g. as an inlet or outlet valve.

[0267] For example, when the first access 121 is an inlet and the second access 122 is an outlet, the valve assembly functions as an inlet valve. In this case, the actuator 152 “pushes” the sealing body assembly 13 into a sealing engagement with sealing surface 14, and for example only opens when a pressure difference between the first access 121 and the second access 122 exceeds a threshold.

[0268] Conversely, when the first access 121 is an outlet and the second access 122 is an inlet, the actuator 152 may be actuated in such a way as to “open” the valve assembly under certain conditions (e.g., in case a pressure difference is sensed and/or at defined times), i.e., provide a “pulling” force to open the valve assembly under these conditions.

[0269] It will be understood that the description of the force unit 15 provided above merely serves as an example and that different embodiments may also be realised. That is, not every embodiment of the force unit 15 may comprise an annular magnet 151, an actuator 152 and/or a coupling unit 153. For example, the annular magnet 151 may be directly connected to the actuator 152, i.e. without a coupling unit 153. Similarly, the basing unit 15 may instead comprise at least one solenoid 155, which may exert a force onto the sealing body assembly 13 via the magnetic portion 132 and which may simply change the direction of the applied force by reversing the direction of the current flow through the (coil of the) solenoid 155. Such an implementation would for example neither require an actuator 15, nor a coupling unit 153 for providing mechanical motion. Thus, it will be apparent for the person skilled in the art that a variety of force units 15 may be realized, which may be configured to exert a force on the magnetic portion 132 of the movable sealing body assembly 13.

[0270] Further, at least a portion of the valve assembly 1 may be surrounded by a cover 16, configured to shield the magnetic field and/or to protect at least a portion of the valve assembly 1 from environmental influences such as contamination, e.g. dust or dirt. For example, the cover 16 may encase the annular magnet 151 and the portion of the valve chamber 11 around which the annular magnet 151 may be moved. Generally, the cover 16 may preferably at least encase the portion of the force unit 15 providing (e.g. generating) the magnetic field that directly acts on the magnetic portion 132 of the valve assembly 1, e.g. the annular magnet 151 or an solenoid 155, which are fitted around at least a portion of the valve chamber 11 and/or the chamber body 131. The cover 16 may be made from a ferrite or a ferromagnetic material and it may preferably be designed such that the magnetic field inside is directed directly and homogeneously into the valve chamber 11. In other words, an outer cover 16, preferably made of ferrite or ferromagnetic material, may serve as an outer shield for the magnetic field and as protection against environmental influences such as contamination.

[0271] With reference to FIG. 3 for example also a 3/2-way valve may be realized in a similar way. The valve assembly 1 also comprises a valve chamber 11 formed by a chamber body 111 and in this case two chamber seals 112A, 112B. The two chamber seals 112A, 112B may preferably be placed at opposite ends of the chamber body 111. Each of the two chamber seals 112A, 112B may comprise an access to the valve chamber 121, 123, i.e. one chamber seal 112A may comprise the first access 121 and the other chamber seal 112B may comprise a third access 123. The second access 122 may for example be in a similar position as for the embodiment discussed with reference to FIG. 1. That is, it may be in the chamber body 111. Such a valve chamber may advantageously not comprise a dead volume as the chamber can be flushed by subsequently opening the first access 121 and the third access 123. In contrast an embodiment such as the one depicted in FIG. 1 may comprise dead volume as the portion of the chamber opposite to the first access may not be directly flushed independent of the configuration assumed by the valve.

[0272] The valve assembly 1 may comprise a corresponding sealing surface 14A and 14B for the first access 121 and the third access 123, respectively, which may be located within the valve chamber 11. Further, each of the sealing surfaces 14A and 14B may comprise an orifice 141A, 141B fluidly connecting the valve chamber 11 to the respective access 121, 123. The sealing surfaces 14A and 14B may each be comprised by one of the chamber seals 112A, 112B.

[0273] Within the valve chamber 11 may be the sealing body assembly 13 which may comprise a magnetic portion 132, such as a magnetic core made of ferromagnetic material, e.g. a bar magnet. Further, the sealing body assembly 13 may comprise two sealing portions 131A, 131B. The sealing body assembly 13 and particularly the sealing portions 131A, 131B may be placed within the valve chamber 11 such that each sealing portion 131A, 131B may be aligned with the complementary sealing surface 14A, 14B. Preferably, the sealing portions 131A, 131B may be located at opposite ends of the sealing body assembly 13 and consequently, the sealing surfaces 14A, 14B may be located at opposite ends of the valve chamber 11, e.g. each in one of the chamber seals 112A, 112B which may be at opposite ends of the valve chamber 11. The sealing portions 131A, 131B and the sealing surfaces 14A, 14B may preferably be aligned along the central axis A1. Further, the sealing body assembly 13 may move along that central axis A1, i.e. the sealing body assembly 13 may move in a direction parallel to the central axis A1. In the depicted embodiment this is the X-direction.

[0274] The sealing body assembly 13 may be configured such that it can move within the valve chamber 11. In particular, it may be configured such that it may not fill the entire chamber volume. Particularly, the sealing body assembly 13 may be configured such that at most one sealing portion 131A, 131B can form a leak-tight connection with the corresponding sealing surface 14A, 14B at the same time. Thus, the valve assembly 1 may assume a first configuration I, wherein the first access 121 is sealed and the third access 123 is fluidly connected to the second access 122. For example, the sealing portion 131A and the sealing surface 14A may form a leak-tight connection to block the fluidic connection between the valve chamber 11 and the first access 121. In the first configuration I, the third access 123 may not be blocked by the sealing body assembly 13. Furthermore, the valve assembly 1 may assume a second configuration II, wherein the third access 123 is sealed and the first access 121 is fluidly connected to the second access 122. In addition, the valve assembly 1 may assume a third configuration III, wherein the first 121, second 122 and third 123 access may be fluidly connected to each other via the valve chamber 11.

[0275] Thus, the valve assembly 1 according to the embodiment depicted in FIG. 3 may selectively connect the first access 121 or the third access 123 to the second access 122. The basic principle is similar to a passive 3/2-way check valve, i.e. a pressure difference between the first 121 (or third 123) access and the valve chamber 11 may principally move the sealing body assembly 13 and thus alter the configuration the valve assembly assumes. However, the switching characteristics of the valve assembly 1 may be altered by a force exerted onto the sealing body assembly 13 through the force unit 15.

[0276] An active 3/2-valve according to the present invention may for example advantageously be used as proportioning valve. That is, the first access 121 and the third access 123 may for example each be connected to a solvent supply, such that a desired solvent combination, e.g. mixture, may be provided at the second access. In particular, the valve 1 may alternately open (and close) the first and third access such that a desired mixture of the respective solvents is supplied at the second access 122. Embodiments of the present invention may particularly allow for fast and reliable switching such that a mixing of the solvents may be achieved within the valve chamber 11. In other words, an active 3/2-valve according to the present invention may advantageously be used as a mixing valve.

[0277] As described above, the force unit 15 may comprise an annular magnet 151 which may exert a force onto the sealing body assembly 13 (when annular magnet 151 and sealing body assembly are not in a relative position that leads to an equilibrium of forces therebetween). This force may be sufficient to open and/or close (i.e. block) a desired access (e.g. of the first 121 and third access 123), even against a pressure difference. For example, if there is a pressure difference between the first access 121 and the valve chamber 11, wherein the pressure is lower in the valve chamber than in the first access 121, the sealing body assembly 13 would generally be pushed away from the first access 121 and a fluid connection between the first access 121 and at least the second access 122 would be established. However, by applying a force that pushes the sealing body assembly 13 towards the first access 121 and more particular against the corresponding sealing surface 14A, the first access 121 may remain blocked even when a pressure difference exists. Further, the first access may be opened even though the valve chamber 11 is at a higher pressure than the first access 121 by applying a force with the force unit 15 that pushes the sealing body assembly 13 away from the first access 121 and the respective sealing surface 14. This may be particularly useful for purging or backflushing any component fluidly connected to the first access 121, e.g. a pump. Again, the pressure difference that may be overcome may be limited to pressure differences below, or equal to the differential pressure threshold. The above may generally also apply for the third access 123.

[0278] It will be understood that a pressure difference between the first access 121 and the third access 123 may consequently reflect a pressure difference between one of the accesses and the valve chamber 11, because at least one of the two access 121, 123 may always be fluidly connected to the valve chamber 11. In other words, if the first access 121 is supplied with a fluid at a higher pressure than the third access 123, the sealing body assembly 13 would be pushed towards the third access 123 and potentially seal the third access 123. Thus, the valve chamber 11 would be pressurized to approximately the pressure at the first fluid supply 121. If the pressure difference is within the boundaries that may be overcome by the force unit 15, i.e. if the pressure difference is not greater than the differential pressure threshold, the valve assembly may actively open the third access 123 and close the first access by exerting a force to the sealing body assembly 13 that pushes it towards the first access 121.

[0279] With reference to FIG. 4, the force unit 15 of the valve assembly 1 may comprise an annular magnet 151, an actuator 152 and a coupling unit 153, wherein the actuator 152 may be configured to provide a linear motion that may be transmitted to the annular magnet 151 by means of a coupling unit 153. The linear motion may be provided such that the annular magnet may be moved with respect to the valve chamber 11 in the x-direction, i.e. along the central axis A1.

[0280] Further, the valve assembly 1 may preferably comprise a cover 16, which may encase at least a portion of the valve assembly 1. The cover 16 may be configured to protect the encased portions of the valve assembly 1 from environmental influences, e.g. contamination, and/or to act as a shield for magnetic fields, e.g. originating from the annular magnet 151. Thus, the cover 16 may preferably be made out of a ferrite or a ferromagnetic material and for example be cylindrically shaped. Preferably, the cover 16 may at least encase the portion of the force unit 15 providing (e.g. generating) the magnetic field that directly acts on the magnetic portion 132 of the valve assembly 1, e.g. the annular magnet 151 or an solenoid fitted around at least a portion of the valve chamber 11 and/or the chamber body 131. In case the force unit 15 comprises moving portions, the cover 16 may further encase at least the portion of the valve chamber 11 along which the magnetic-field-providing portion of the force unit 15, e.g. the annular magnet 151, may be moved (e.g. through the actuator 152).

[0281] Again, it will be understood that the above description merely concerns an exemplary embodiment of the valve assembly 1 and particularly the force unit 15 and that other embodiments may also be realised within the scope of the present invention. It will be apparent for the person skilled in the art that also other embodiments of the force unit 15 may be realized, wherein the force unit 15 may be configured to exert a force on the magnetic portion 132 of the movable sealing body assembly 13.

[0282] Generally, the chamber body 111 of the valve chamber 11 may for example be a pressure-resistant tube, configured to withstand typical pressures and liquids used in HPLC. The ends of the pressure-resistant tube may be sealed by means of corresponding chamber seals 112. Further, the sealing portion 131 of the sealing body assembly 13 may for example be a one-sided tip, which may be configured to form a leak-tight connection to the at least one sealing surface 14, which may also be referred to as sealing seat. The at least one sealing surface 14 may for example be comprised by a respective chamber seal 112.

[0283] Thus, a valve assembly in a 2/1-way or 3/2-way version may for example be constructed as follows: In a pressure-resistant tube comprising a corresponding wall thickness, which may be made of a material resistant to liquids used in HPLC, e.g. chemically inert (such as low or no iron content), and non-ferromagnetic (e.g. titanium, more particularly titanium grade 5 (3.7164/3.7165), or MP35N), and at the ends of which a high-pressure static seal is fitted, there may be a translationally movable sealing body assembly 13 with a permanent magnetic portion 132, e.g. a cylindrical core. The outside, e.g. outer shell, of the movable sealing body assembly 13 may also be mechanical and chemical resistant to the surrounding liquid pressure and the typical liquids used. The movable sealing body assembly 13 may comprise at least one sealing portion 131, e.g. one-sided tip, which in turn may seal against a corresponding sealing surface 14, also referred to as sealing seat, in the chamber body 111 or the chamber sealing 112.

[0284] Further, an active force coupling to the (at least partially permanent magnetic) movable sealing body assembly 13 may be realized with an outer permanent magnetic annular magnet 151, which may be designed such that a gap to the outer diameter of the pressure-resistant and non-ferromagnetic tube, i.e. the chamber body 111, is minimized. By active, predominantly axial displacement of the outer annular magnet 151, the inner sealing body assembly 13 may be pressed onto or pushed away from the sealing surface 14 (e.g. into or out of the sealing seat).

[0285] Through an initial calibration, e.g. by applying high hydraulic pressure, for example the softer sealing portion 131 (e.g. tip) may be formed by the harder sealing surface 14 (e.g. sealing seat) in such a way that a very precise (fitting) sealing contour may be produced, which in turn may provide a leak-tight seal in the desired direction.

[0286] It will be understood that for this process it may generally not be relevant whether the movable sealing body assembly 13, particularly the corresponding sealing portion 131, or the sealing surface 14 (e.g. the sealing seat) is made of a slightly harder material. That is, primarily the presence of a difference in the (degree of) hardness of the material matters. However, there may still be other considerations that lead to a portion being preferably the harder/softer portion, e.g. it may be preferably that the moving portion, i.e. the sealing portion 131 is harder than the sealing surface 14, which is generally fixedly mounted.

[0287] Some more examples for embodiments of the valve assembly may be discussed in the following, however, it will be understood that theses merely serve as examples and do not, in any way, limit the scope of the present invention.

[0288] For example, the force unit 15 may comprise at least one solenoid 155 fitted around at least a portion of the valve chamber 11 and/or the chamber body 131. That is, similar to the annular magnet 151, the valve chamber 11 may run through the central opening of the at least one solenoid 155. Preferably, the solenoid 155 may be tightly fitted to the valve chamber 11. That is, the space between the surface within the opening of the solenoid and the outer surface of the chamber body 11 may be minimized. Generally, a solenoid may denote a preferably cylindrical coil of wire, that may act as a magnet when a current is running through the wire.

[0289] It will be appreciated that for a solenoid 155, the direction of the magnetic field generally depends on the direction of a current running through wires of the solenoid 155. Thus, a solenoid may generate a magnetic field which may act in opposite directions based on the direction of the current in the solenoid 155. Thus, already a single solenoid 155 may be sufficient as a force unit 15. The solenoid may generally create a magnetic field which may be approximately uniform within the solenoid, i.e. within the opening comprising at least a portion of the valve chamber 11, and substantially perpendicular to the current, i.e. perpendicular to the preferably circularly shaped faces of the solenoid 155. Thus preferably, at least a portion of the magnetic field within the solenoid may be aligned with the central axis A1.

[0290] Thus, the magnetic field generated by the at least one solenoid 155 may exert a force on the magnetic portion 132 of the sealing body assembly 13, wherein the direction of the force may be controllable through the direction of the current applied to the solenoid 155. In some embodiments, the solenoid 155 may further be combined with a permanent magnet that may constantly provide a certain bias or preload on the sealing body assembly 13, for example for a magnetically preloaded pump inlet or outlet valve.

[0291] With reference to FIG. 5, the force unit 15 may for example comprise two solenoids 155A, 155B, wherein the valve chamber 11 may be located in the opening of each of the two solenoids 155A, 155B. That is, preferably, each of the two solenoids 155A, 155B may encompass a portion of the valve chamber 11. Thus, the sealing body assembly 13 may generally be moved through a magnetic force acting on the magnetic portion 132 which may be exerted by one or both of the solenoids 155A, 155B. For example, the first solenoid 155A may generate a magnetic field configured to attract the magnetic portion 132. In addition, the second solenoid 155B can generate a magnetic field configured to repel the magnetic portion 132, such that both solenoids 155A, 155B generate a field that is pushing (repelling) and/or pulling the sealing body assembly 13 towards the first solenoid 155A, e.g. in positive x-direction. Alternatively, it may be sufficient for only either the first solenoid 155A or the second solenoid 155B to generate the respective field. Thus, either by changing the direction of the current through both solenoids 155A, 155B or alternatively by switching between the two solenoids 155A, 155B each generating an attractive (or repulsive) magnetic field, the sealing body assembly 13 may be moved within the valve chamber 11 and thus the configuration the valve assembly 1 assumes may be actively controlled through the force unit 15, i.e. in this embodiment the solenoids 155A, 155B. In particular, the force unit 15 may control the configuration of the valve without the need of a mechanical link between the force unit 15 and the sealing body assembly 13. That is, the use of magnetic force may advantageously allow for exerting a force on the sealing body assembly 13 without need for physical contact, i.e. contactless. This may be particularly advantageous as no moving part is required between the inside and outside of the valve chamber, which would otherwise necessitate complex and difficult sealing.

[0292] It will be understood that it may also be feasible to place the valve chamber 11 between the two solenoids, e.g. in a Helmholtz coil.

[0293] With reference to FIG. 6 alternative embodiments of the sealing body assembly 13 are discussed. Generally, the sealing body assembly 13 may also be realized different to the embodiments discussed above. For example, the at least one sealing portion 131, 131A, 131B may be integrally formed with at least one further portion of the sealing body assembly 13, e.g. the remaining portion of the sealing body assembly 13. That is, instead of separate elements, e.g. balls, which are permanently fixed or mounted to the remaining portion of the sealing body assembly 13, the sealing body assembly 13 may be formed to comprise a sealing portion 131, 131A, 131B, which may be integral to the remaining portion of the sealing body assembly 13. Such a sealing portion 131 may for example take the form of a tip, such as a rounded tip, or a conical frustum. Again, it may be advantageous if the sealing portion 131, 131A, 131B comprises a different hardness to the sealing surface 14, 14A, 14B to allow for a calibration (e.g. forming/shaping) of the softer portion (i.e. sealing portion 131, 131A, 131B or sealing surface 14, 14A, 14B).

[0294] Additionally or alternatively, the sealing body assembly 13 may generally be formed of a magnetic material, that is, the sealing body assembly 13 may for example be formed of a ferromagnetic material. In other words, the magnetic portion 132 of the sealing body assembly 13 may correspond to the entire sealing body assembly 13.

[0295] Generally, the sealing body assembly 13 may comprise a corrosion-resistant coating. This may be advantageous if the sealing body assembly 13 is made of a material that is not corrosion-resistant, as the sealing body assembly 13 is subjected to any fluid passing through the valve chamber 11. Alternatively, at least an exterior portion of the sealing body assembly 13 may be corrosion-resistant. The exterior portion may be any portion of the sealing body assembly 13 that will get into contact with a fluid surrounding the sealing body assembly 13.

[0296] In other words, a 3/2-way valve (assembly) according to the present invention may for example be realized as depicted in FIG. 6, wherein the configuration of the valve assembly 13 may for example be switched via two fixed, alternately operated solenoids 155A, 155B. The valve assembly 1 may further comprise a translationally movable sealing body assembly 13, which may preferably be made of corrosion-resistant, ferromagnetic and/or magnetisable material, wherein the ends of the sealing body assembly 13 may be formed as sealing portions 131, e.g. sealing tips. In other embodiments, the sealing body assembly 13 may comprise a corrosion-resistant coating. Advantageously, the sealing portion 131 may be made of a slightly harder (or softer) material than that of the complementary sealing surface 14 (e.g. sealing seat), which may for example be a bore in a pressure-resistant tube. This may for example allow to calibrate (e.g. shape) the sealing interface by applying a hydraulic pressure, that presses the sealing portion 131 into the respective sealing surface 14. Alternatively, the calibration may also be achieved by applying a mechanical force instead of hydraulic pressure. In this case prior molding of the sealing surface 14 may also be used. The sealing interface, i.e. the projected area of the seal pairing (sealing portion 131, sealing surface 14) may be minimized. For example, the corresponding bore diameter could be approx. 0.4 mm and the movable cylindrical sealing body assembly 13 with one-sided sealing tip could have an outer diameter of approx. 2.5 mm. This may advantageously allow for reduced sealing forces applied to the movable sealing body assembly 13 and/or an improved leak tightness.

[0297] In general, it may be preferred, that the sealing portion 131 is made of a harder material compared to the sealing seat 14, since the sealing seat 14 may typically be fixedly mounted, i.e. it does not move during normal operation, and my slightly deform with every closing of the respective access.

[0298] Likewise, the material combination of the movable sealing body assembly 13 comprising, for example, a permanent magnetic core and a surrounding exterior portion with a one- or double-sided tip, may be slightly harder or softer than the corresponding sealing surface 14. The advantageous factor also being that a one-off hydraulic or mechanical calibration of the contact surface between the sealing surface 14 and the sealing portion 131 (i.e. the sealing interface) at the factory may be possible.

[0299] With reference to FIGS. 7A and 7B, a further exemplary embodiment of the valve assembly 1 is discussed. Generally, the sealing body assembly 13 may not entirely be located within the valve chamber 11. That is, a portion of the sealing body assembly 13 may be located outside of the valve chamber 11. In particular, the magnetic portion 132 of the sealing body assembly 13 may be located outside of the valve chamber 11, e.g. in a fluidly connected cavity 17.

[0300] That is, the valve chamber 11 may comprise the at least one sealing portion 131 of the sealing body assembly 13, while the magnetic portion 132 may be located in the cavity 17, which may preferably be aligned with the valve chamber 11. That is, preferably the central axis A1 may run centrally through both, the valve chamber 11 and the cavity 17 in x-direction. Moreover, the central axis may run centrally through the sealing portion 131 and the sealing surface 14.

[0301] Referring to FIG. 7A, the valve chamber 11 may comprise a chamber body 111 and a chamber seal 112 at one end of the valve chamber 11, wherein the chamber seal 112 may for example comprise the third access 123 to the valve chamber 11. At the opposite end of the valve chamber 11 the first access 121 may be provided. However, different to embodiments shown before, the sealing body assembly 13 may extend through the opening that provides the first access 121 to the valve chamber 11. The portion of the sealing body assembly 13 extending outside of the valve chamber 11 may preferably comprise the magnetic portion 132. Typically, there may be a trade-off between the magnetic field strength the force unit 15 may generate and the size of the magnetic portion 132 of the sealing body assembly 13 that is susceptible to the generated magnetic field. Thus, the magnetic portion 132 may not be arbitrarily small but instead limited to a minimal size required for sufficient force transmission, which may depend on the magnetic field generated by the force unit 15, but also on the geometry and material of the magnetic portion 132. Thus, locating the magnetic portion 132 of the sealing body assembly 13 outside the valve chamber volume may be advantageous for reducing said chamber volume and consequently the dead volume of the valve chamber 11.

[0302] The magnetic portion 132 of the sealing body assembly 13 may for example be located in a cavity 17 next to the valve chamber 11, which may comprise a larger volume than the valve chamber 11.

[0303] The second access 122 may be provided to the valve chamber 11 at a point in between the two ends comprising the first 121 and the third 123 access.

[0304] The at least one sealing portion may for example be shaped as a conical frustum 131A, 131B which may seal against correspondingly shaped sealing surfaces 14A, 14B. For example, the shape of the sealing surfaces 14A, 14B may be individually calibrated during the manufacturing process to substantially match the respective sealing portion 131A, 131B. Again, the calibration may for example be realized by applying a hydraulic or mechanical pressure that presses the sealing portion 131A, 131B into the respective sealing surface 14A, 14B, wherein there is a difference in the degree of hardness of the material between the sealing portion 131A, 131B and the respective sealing surface 14A, 14B, such that the softer portion is adapted to fit the harder portion in a sealing manner (i.e. sealingly).

[0305] Thus, in a first configuration I (depicted in FIG. 7A), the third access 123 may be fluidly connected to the second access 122 via the valve chamber 11, while the sealing portion 131A of the sealing body assembly 13 is pressed against the respective sealing surface 14A. Thus, the first access 121 may be sealed and there may be no fluidic connection between the valve chamber 11 and the cavity 17 comprising the magnetic portion 132 of the sealing body assembly 13.

[0306] In a second configuration II (not shown) the sealing body assembly 13 may be pushed towards the chamber seal 112, i.e. in the negative x-direction, such that the sealing portion 131B and the respective sealing surface 14B may form a leak-tight connection and thus block the fluidic connection between the third access 123 and the valve chamber 11. At the same time, the sealing portion 131A may be separated from the respective sealing surface 14A such that the first access 121 may be fluidic connected to the second access 122. Thus, the cavity 17 may be fluidic connected to the valve chamber 11.

[0307] In other words, such a design may provide a significantly reduced volume surrounding the translationally movable sealing body assembly 13 within the valve chamber 11. That is, the valve chamber volume that is not filled with a portion of the movable sealing body assembly 13 may be reduced compared to other embodiments. Thus, particularly when assuming configuration I the dead volume of the fluidic connection between the second access 122 and the third access 123 may be reduced compared to other designs. It may be realised by placing the preferably permanently magnetic and corrosion-resistant coated magnetic portion 132 in a further adjacent cavity 17. The depicted valve assembly 1 is designed as a 3/2-way valve. However, it will be understood, that the same principle may be applied to a 2/1-way valve.

[0308] With reference to FIG. 7B, the second 122 and third 123 access may be directly connected to a fitting 182, 183, which may also be referred to as a fluidic connector 182, 183, thus allowing to directly connect the second 122 and third 123 access to a respective capillary. The first access 121 may fluidic connect the valve chamber 11 to the cavity 17 comprising a portion of the sealing body assembly 13, preferably at least the magnetic portion 132 of the sealing body assembly 13. The cavity 17 may further be fluidly connected to a fitting 181 (which may also be referred to as a respective fluidic connector 181) such that the first access 121 may be fluidly connected to the respective fluidic connector 181 via the cavity 17.

[0309] The actuator 15 may comprise two permanent bar magnets 156A, 156B which may be magnetized along the x-direction, wherein the two bar magnets 156A, 156B are for example mounted to an actuator 152 such that the magnetization direction of the first bar magnet 156A is opposite to the magnetization of the second bar magnet 156B. That is, the two bar magnets 156A, 156B may each be magnetized along the direction of the central axis A1, however, in opposite directions. Further they may be mounted to an actuator 152 such that a single bar magnet 156A, 1566 may selectively be aligned with the magnetic portion 132 of the sealing body assembly 13. Thus, when for example the first bar magnet 156A is aligned with the magnetic portion 132 of the sealing body assembly 13 it may exert an attractive force on the magnetic portion 132 pulling the sealing body assembly 13 towards the bar magnet 156A (cf. FIG. 7A). Consequently, the valve assembly 1 may assume the first configuration I. In contrast, when the second bar magnet 156B is aligned with the magnetic portion 132 of the sealing body assembly 13 it may exert a repulsive force on the magnetic portion 132 pushing the sealing body assembly 13 away from the bar magnet 156B. Thus, the valve assembly 1 may assume the second configuration II. It will be understood that also the first magnet 156A may exert a repulsive force while the second magnet 156A exerts an attractive force. However, the two bar magnets 156A, 156B may always be aligned opposite to each other in terms of magnetization. Furthermore, it will be understood by the person skilled in the art, that a bar magnet may generally denote an elongated magnet with two poles at the respective ends. Particularly a bar magnet may not be limited to a rectangular-shaped bar magnet but may for example also denote a cylindrically-shaped bar magnet (also referred to as rod magnet) or other shapes such as a bar magnet with an elliptical cross section.

[0310] In other words, the force unit 15 may generally comprise two bar magnets 156A, 156B, which may be mounted to the actuator 152 next to each other in the direction of the linear or rotational displacement provided by the actuator 152. Furthermore, the respective magnetization direction of the two bar magnets may be oriented in opposite directions and perpendicular to the direction of the displacement provided by the actuator 152. The actuator 152 may be configured to linearly or rotationally displace the bar magnets 156A, 156B within a plane perpendicular to the central axis A1 and thereby selectively align one of the bar magnets 156A, 156B with the magnetic portion 132 of the sealing body assembly 13 in a plane perpendicular to the central axis.

[0311] Thus, by coupling the two bar magnets to an actuator 152, either directly or via a coupling unit 153, which may provide a linear or rotational motion, any one of the two bar magnets 156A, 156B may be aligned with the magnetic portion 132 and thus by changing the bar magnet that is aligned with the magnetic portion 132 of the sealing body assembly 13, the configuration assumed by the valve assembly 13 may be actively changed and/or supported. Therefore, the force unit 15 may allow to actively and deterministically switch the configuration assumed by the valve assembly 1, at least up to a maximal pressure difference specified by the differential pressure threshold.

[0312] It will be understood that generally any of the at least one sealing portion 131 may also assume another shape such as a tip, particularly sealing portion 131B in the depicted embodiment (FIG. 7A).

[0313] In other words, a 3/2-way valve assembly comprising for example a cylindrical magnetic portion 132 in a cavity 17 adjacent to the valve chamber 11 may be switched via a force unit 15 comprising a bar magnet 156A with magnetisation direction parallel to the central axis A1 and another axially oppositely polarised bar magnet 156B. Further, both bar magnets 156A, 156B may for example be displaceable in a common support (coupling unit 153) along an axis perpendicular to the opposing magnetization directions by an actuator 152 e.g. with a lifting magnet, so that either the bar magnet 156A or the bar magnet 156B aligns to an axis with the magnetic portion 132, e.g. the central axis A1 of the valve chamber 11.

[0314] Generally, a valve assembly according to the present invention may for example comprise a movable sealing body assembly 13 comprising a permanent magnetic core (i.e. a magnetic portion 132) and an exterior portion surrounding the magnetic core, which comprises a sealing portion 131, e.g. in form of a one-sided tip, which may at least be slightly softer, or alternatively harder, than the complementary sealing surface 14, e.g. sealing seat 14. That is, the sealing portion 131 and the sealing surface 14 may differ as regards their respective hardness. Furthermore, the sealing interface, i.e. the contact area of the sealing portion 131 and the sealing surface 14, may be calibrated (e.g. formed/shaped) during production by pressing the sealing geometry into the respective sealing portion 131 and/or sealing surface 14 or by pressing the sealing portion 131 into the sealing surface 14 when the valve assembly is in an assembled state, e.g. by applying a hydraulic pressure. The exterior portion may generally provide protection of the magnetic portion 132 against chemical and/or mechanical stress.

[0315] Further, an opening or closing force may be actively applied via a force unit 15 to the centrally positioned and translationally movable sealing body assembly 13 comprising the magnetic portion 132. The force unit 15 may comprise at least one outer permanent annular magnet 151 or at least one magnetic coil 155 with a homogeneous magnetic field in the centre or a plurality of permanent-magnetic bar magnets 156A, 1566, can be axially pivoted and/or displaced in alternating orientation of the poles by means of the actuator 152. The valve assembly 1 may thus advantageously provide means to actively switch the flow direction at a pressure significantly lower than system pressure and at the same time a passive seal, e.g. on at least one side, as a check valve at system pressure. Further, it may enable for active interruption and release of flow at differential pressures typically up to a differential pressure threshold of for example approximately 50 bar, while generally at applied system pressure.

[0316] Overall, a valve assembly 1 according to the present invention may allow for a higher reliability for particle-contaminated fluids and a more uniform tightness across the pressure range. In particular, the configuration of the valve assembly 1 may also be deterministically switched (e.g. it may be opened or closed) at low differential pressures and independent of the spatial orientation of the valve (i.e. independent of gravity). Similarly, it may overcome the problem of faulty closing behaviour for poorly degassed fluids, due to air bubbles which may be trapped within the check valve.

[0317] Further, it provides faster switching times than passive check valves and active control of the flow direction for limited differential pressures, i.e. up to the differential pressure threshold, even at high system pressures.

[0318] Furthermore, a valve assembly 1 according to the present invention may be utilized within a pump system comprising at least one pump unit, for example as an inlet valve and/or outlet valve to the at least one pump unit. This may be particularly interesting if the pump unit is a positive displacement pump unit, for example a piston pump unit. The pump system may also comprise a plurality of pump units which may be operated in parallel, series or any combination thereof. That is, it may also be used in a system comprising four pump units, with two parallel flow paths, whereof each comprises two pump units in series. Utilizing a valve assembly according to the present invention in a pump system may be advantageous, as it may provide a reduced complexity and/or increased robustness in comparison to known (active) check valves. Thus, the pump system would be rendered less complex and/or more robust, which may for example be advantageous for manufacturing, installation, use and maintenance of the pump system. Further, such a pump system may provide the possibility of reversing the flow, particularly if all check valves of the pump system are valve assemblies according of the present invention. This may advantageously provide improved flushing behaviour for piston pumps, i.e. it may enable effective purging of piston pumps. Yet further, such a pump system may allow for improved diagnostic procedures, e.g. for controlling the flow of the at least one pump and/or for avoiding pressure drops when alternately conveying a fluid with two pump pistons.

[0319] Whenever a relative term, such as “about”, “substantially” or “approximately” is used in this specification, such a term should also be construed to also include the exact term. That is, e.g., “substantially straight” should be construed to also include “(exactly) straight”.

[0320] Whenever steps were recited in the above or also in the appended claims, it should be noted that the order in which the steps are recited in this text may be accidental. That is, unless otherwise specified or unless clear to the skilled person, the order in which steps are recited may be accidental. That is, when the present document states, e.g., that a method comprises steps (A) and (B), this does not necessarily mean that step (A) precedes step (B), but it is also possible that step (A) is performed (at least partly) simultaneously with step (B) or that step (B) precedes step (A). Furthermore, when a step (X) is said to precede another step (Z), this does not imply that there is no step between steps (X) and (Z). That is, step (X) preceding step (Z) encompasses the situation that step (X) is performed directly before step (Z), but also the situation that (X) is performed before one or more steps (Y1), . . . , followed by step (Z). Corresponding considerations apply when terms like “after” or “before” are used.

[0321] While in the above, a preferred embodiment has been described with reference to the accompanying drawings, the skilled person will understand that this embodiment was provided for illustrative purpose only and should by no means be construed to limit the scope of the present invention, which is defined by the claims.