Microfluidic multi-channel rotary valve system

Abstract

A micro fluidic rotary valve (2) comprising a stator (4), a rotor (6), and an actuator (8) coupled to the rotor for turning the rotor (6) relative to the stator (4). The stator (4) comprises a stator body having a rotor receiving cavity (24) defining an inner bearing surface (16), and a plurality of ports (12) connectable to fluid conduits for the supply or extraction of fluids, the ports (12) having orifices that open onto the inner bearing surface (16). The rotor comprises a rotor body (14) having an outer bearing surface (18) in contact with the stator inner bearing surface (16), the outer bearing surface (18) of the rotor body (14) comprising a plurality of groove channels (20) distributed around the circumference of the outer bearing surface (18) each groove channel (20) interconnecting at least two ports of said plurality of ports forming a pair of ports at a specific angular orientation of the rotor relative to the stator, different groove channels (20) interconnecting different pairs of ports of said plurality of ports at different specific angular orientations of the rotor relative to the stator.

Description

[0001] MICROFLUIDIC MULTI-CHANNEL ROTARY VALVE SYSTEM

[0002] The present invention relates to a microfluidic rotary valve with multiple ports and fluidic interconnections for a microfluidic distribution system.

[0003] There are many microfluidic applications requiring the distribution of a plurality of different liquids and reagents between a plurality of input and output ports. Such microfluidic applications may concern for instance assays on biological matter, or distributing various reagents or chemicals to perform high-throughput macromolecule characterization such as PCR, generate droplets sequence useful for cell screening or synthesize micro and nanoparticles. In many microfluidic applications, the typical range of liquid volumes pumped per cycle may for instance be in a range of 0.001 mL to 10 mL or more. Certain applications may for instance require many ports, for instance in a range of 5 to 100 ports whereby one or more ports may be an outlet port and there are many inlet ports, or vice versa one or more ports are inlet ports and the remaining many ports are outlet ports, or some or all of the ports may both act as inlet ports and outlet ports depending on the pumping direction and application.

[0004] Rotary valves for interconnecting various selected ports of a multiport system typically comprise a planar first disk having fluidic channels and a counter cylinder or disk rotating relative to the first disk with one or more fluidic channels that interconnect with the channels formed on the first disk. Different interconnections are formed by rotation of the disk. Such a design has the advantage of being able to easily design and manufacture the various channels on the planar disks. However, one of the drawbacks of such axial valve configuration is the limited number of interconnections that can be placed on the disk without increasing the diameter of the valve and therefore increasing the overall size thereof. Also, the accuracy in the positioning of the valve inputs and outputs relative to the valve inlets and outlets will depend on the position of the inlets and outlets relative to the radius. Another problem with regard to the sealing is that the planarity of the disk faces will affect the sealing quality. Also, to obtain a good sealing, means to apply the required thrust pressure on the interface is needed.

[0005] In certain applications there is a desire to have a large number of interconnections while maintaining a compact device. Moreover, there is also a need to ensure good interconnection and sealing as well as rapid change in fluidic interconnections. In view of the foregoing, it is an object of this invention to provide a microfluidic rotary valve for a microfluidic distribution system that can be rapidly and accurately actuated for different fluidic interconnections in a compact and economical manner and with good sealing.

[0006] It is advantageous to provide a microfluidic rotary valve that is durable.

[0007] It is advantageous to provide a microfluidic rotary valve that is economical to manufacture.

[0008] Objects of the invention have been achieved by providing a system according to claim 1.

[0009] Dependent claims set out various advantageous features of embodiments of the invention.

[0010] Disclosed herein is a micro fluidic rotary valve comprising a stator, a rotor, and an actuator coupled to the rotor for turning the rotor relative to the stator. The stator comprises a stator body having a rotor receiving cavity defining an inner bearing surface, and a plurality of ports connectable to fluid conduits for the supply or extraction of fluids, the ports having orifices that open onto the inner bearing surface. The rotor comprises a rotor body having an outer bearing surface in contact with the stator inner bearing surface, the outer bearing surface of the rotor body comprising a plurality of groove channels distributed around the circumference of the outer bearing surface. Each groove channel interconnects at least two ports of said plurality of ports forming a pair of ports at a specific angular orientation of the rotor relative to the stator, different groove channels interconnecting different pairs of ports of said plurality of ports at different specific angular orientations of the rotor relative to the stator.

[0011] In an advantageous embodiment, the rotor body has an uncompressed outer diameter (DRd) of the outer bearing surface, and the stator body has an inner bearing surface with inner diameter (DSi) in an uncompressed state, said outer diameter (DRd) being greater than said inner diameter (DSi) such that the outer bearing surface is elastically biased against the inner bearing surface, at least one of the rotor and stator being elastically compressible or expandable.

[0012] In an advantageous embodiment, the degree of elastic compression of the rotor body relative to the stator body is in a range of 0.5 to 5%, preferably in a range of 1.5 to 2.5% relative to said outer diameter.

[0013] In an advantageous embodiment, the rotor body comprises a tubular wall with a center bore. In an advantageous embodiment, the rotor body is elastically compressed to provide over 90% of the compression rate.

[0014] In an advantageous embodiment, a wall thickness (TR) of the rotor body tubular wall is in a range of 5 to 40% of the outer bearing surface diameter {0.05 DRo < TR < 0.4 DRo), preferably in a range of 10% to 20% {0.1 DRo < TR < 0.2 DRo).

[0015] In an advantageous embodiment, the channel grooves have a depth in a range of 0.1 to 2 mm, preferably in a range of 0.2 to 1 mm, and a width between 0.1 to 2 mm, preferably in a range of 0.2 to 1 mm, the outer bearing surface of the rotor body having a diameter in a range of 5 to 60 mm.

[0016] In an advantageous embodiment, the stator comprises between 5 to 100 ports, preferably between 8 to 20 ports.

[0017] In an advantageous embodiment, the rotor body of the rotor is made from a polymer selected from a group consisting of PTFE, UHMW-PE, or compounds based on these materials.

[0018] In an advantageous embodiment, the stator is made of a polymer selected from a group of materials consisting of PEEK, PCTFE, PVDF, or compounds based on these materials.

[0019] In an advantageous embodiment, the rotor body is injection molded.

[0020] In an advantageous embodiment, the stator body is injection molded.

[0021] In embodiments, the rotor body may be machined. In embodiments the stator body may be machined.

[0022] In an advantageous embodiment, the actuator comprises a position encoder having discrete positioning elements mounted on an end wall of the rotor body, the discrete elements comprising magnets, the position encoder further comprising a magnetic field sensor, for instance a Hall sensor mounted on the stator configured to detect the discrete positioning elements and determine therefrom the angular position and displacement of the rotor relative to the stator.

[0023] In an advantageous embodiment, the ports are arranged along an axial band of an outer surface of the stator. In an advantageous embodiment, the rotor body comprises an axial end shoulder abutting against an axial positioning shoulder at an end of the rotor receiving cavity to position the rotor axially with respect to the stator.

[0024] In an advantageous embodiment, the micro fluidic rotary valve is configured for the generation of a sequence of droplets output by different ports during rotation of the rotor body.

[0025] Further advantageous features of the invention will be apparent from the following detailed description of embodiments of the invention and the accompanying illustrations.

[0026] Brief description of the figures

[0027] Figures 1a and 1 b are perspective views of a microfluidic rotary valve of a microfluidic distribution system according to an embodiment of the invention, figure 1a Illustrating the valve with the stator in transparency and figure 1 b illustrating the valve with the rotor features in dotted lines;

[0028] Figure 2a is a side-view of the microfluidic rotary valve according to an embodiment and figure 2b is a cross-sectional view through lines 2b-2b of figure 2a;

[0029] Figure 3a is a perspective view of a microfluidic rotary valve coupled to an actuator according to an embodiment of the invention;

[0030] Figure 3b is a side-view of the microfluidic rotary valve and actuator of figure 3a;

[0031] Figure 3c is a cross-sectional view through line 3c-3c of figure 3b;

[0032] Figure 4a is a perspective view of the microfluidic rotary valve with the stator shown in transparency illustrating stator ports interconnected by groove channels on the rotor, according to an embodiment of the invention;

[0033] Figure 4b is a schematic representation illustrating various examples of interconnections between inlet / outlet ports by channels formed on the rotor depending on the rotational position of the rotor relative to the stator;

[0034] Figure 5 illustrates an assembly of a rotor in a stator of a microfluidic rotary valve according to an embodiment of the invention.

[0035] Referring to the figures, a microfluidic rotary valve 2 according to embodiments of the invention, for a microfluidic distribution system is illustrated. The microfluidic rotary valve 2 comprises a stator 4 and a rotor 6 rotatably mounted within the stator 4. The microfluidic rotary valve 2 further comprises an actuator 8 coupled to the rotor 6 to turn the rotor within the stator.

[0036] The actuator 8 comprises a motor, for instance a stepping motor, having a rotor shaft 32 with a coupling 34 engaging a complementary coupling 30 of the valve rotor 6. The actuator 8 further comprises a position encoder 35 configured to detect the position and rotational displacement of the valve rotor 6.

[0037] In the illustrated embodiment, the position encoder may comprise a plurality of discrete elements such as magnetic elements mounted around the rotor axis in a disk that for instance may be mounted to the valve rotor 6, and a Hall effect sensor (not shown) mounted on a stator portion facing the disk. One of the discrete elements may have a magnetic polarity opposite to the other discrete elements to serve as a reference point to determine the absolute rotation position of the valve rotor 6 relative to the stator 4. Other positioning encoders per se known in the art may however be implemented, for instance an optical position encoder or other forms of magnetic position encoders. The position encoder serves to accurately determine the angular position of the valve rotor 6 and provides feedback to the actuator to rotate the valve rotor relative to the stator in a precise manner for selected valve positions.

[0038] The stator 4 has a stator body with a substantially tubular wall surrounding a rotor receiving cavity 24 that defines an inner bearing surface 16. The stator 4 further comprises ports 12 that serve as inlet and outlet. For many microfluidic applications, the number of ports will typically exceed 5 and may be typically in a range of 5 to 100 ports or more.

[0039] In the illustrated embodiment, there are around 10-12 ports that may be coupled to various conduits, for instance in the form of tubes, connected to a pumping system with one or more pumps and a liquid supply system with a plurality of liquids. One of the ports may for instance serve as an output port and the other ports as input ports, or there may be a plurality of output ports and a plurality of input ports that may be interconnected in various desired configurations depending on the application. A pump may for instance be coupled to an outlet port and have a negative pressure that draws through inlet ports when they are connected to the outlet port depending on the rotational position of the rotor relative to the stator. The pumping system may also comprise positive pressure pumps that push liquid in the inlet and out through the outlet when an interconnection to the inlet and the outlet is formed. There may also be a positive pumping pressure on the inlet side and a negative pumping pressure on the outlet side.

[0040] The inner bearing surface 16 of the rotor receiving cavity 24 may be substantially smooth and continuous, except for the orifices formed by the inlet and outlet ports 12. In the illustrated embodiment, the ports 12 are arranged in rows on an outer side of the stator in a band extending axially, however the ports may be arranged all around the stator and there may also be more than one port grouping, for instance two set of ports on opposed sides of the stator separated substantially by 180°, or at other angles.

[0041] The rotor 6 comprises a rotor body 14 that may either be full and cylindrical, or in a preferred embodiment forming a tubular wall with a center bore 22, the rotor body 14 having an outer bearing surface 18 that interfaces with the inner bearing surface 16 of the stator body 10.

[0042] Channels 20 in the form of grooves are formed into the outer bearing surface 18 of the rotor body 14, the groove channels 20 being formed to interconnect to ports 12 when the rotor is at a specific angular orientation relative to the stator. Different groove channels 20 positioned around the rotor outer bearing surface 18 are configured to interconnect different pairs of ports 12. An example of various possible interconnections are illustrated schematically in figure 4b. In this example, the center port 12c serves as an outlet port and various groove channels interconnect the outlet port to the inlet ports. Any two ports of the multiple ports may however be interconnected by a groove channel 20, the various groove channels being distributed around the circumference of the rotor such that different pairs of ports may be interconnected at different specific angular orientations of the rotor. In view of the large surface area of the rotor outer bearing surface, compared to an axial valve arrangement, a large plurality of ports and different interconnections may be achieved in a compact manner, with easy switching from one pair of open valves to the next by rotation of the rotor in the stator. The rotor may turn a single direction, although rotation in both directions may also be envisaged.

[0043] The groove channels 20 may be very easily formed on the outer surface of the rotor body in an injection molding process, or by etching, machining, or subtractive manufacturing techniques such as laser ablation. Also, different port interconnections can be configured by replacing only the rotor with different channel groove configuration while keeping the stator and actuator unchanged.

[0044] The outer bearing surface 18 of the rotor body 14 has an outer diameter DRo which, prior to assembly in the rotor receiving cavity 24 of the stator 4, is greater than an inner diameter DRi of the inner bearing surface 16. The rotor is elastically compressible or alternatively the stator is elastically extendible, or both the rotor and stator are elastically displaceable in diameter, such that when the rotor is inserted into the rotor receiving cavity 24 of the stator, elastic compression of the rotor and / or elastic extension of the stator occurs such that the outer bearing surface 18 of the rotor elastically presses against the inner bearing surface 16 of the stator. The elastic compression force at the interface between the stator and rotor bearing surfaces 16, 18 advantageously provides a good sealing therebetween that prevents liquid flowing out of the groove channel except when connected to ports, in a simple and economical arrangement.

[0045] Preferably, the relative degree of compression is in a range of 0.1 to 5%, preferably in a range of 0.5 to 2.5%, for instance between 1.5 and 2.5% for preferred materials used for the manufacturing of the rotor body 14 and stator body 10.

[0046] In a preferred embodiment, the rotor body 14 has a tubular wall with a center bore 22 having an inner diameter DRi such that the wall thickness TR of the tubular wall performs over 90% of the elastic displacement, preferably over 95% of the elastic displacement, the stator being significantly less elastic due to the material used, or due to the wall thickness TS of the stator body 10. Since the stator is in contact and coupled to the various external devices, it is preferably more rigid than the rotor body 14.

[0047] The axial position of the rotor in the rotor receiving cavity 24 may be defined by shoulders, for instance an axial end shoulder 28 of the rotor body 14 that bears against an axial positioning shoulder 26 at an axial end of the rotor receiving cavity 24.

[0048] The rotor 6 is provided with a coupling 30 engaging a complementary coupling 34 of the actuator 8. The coupling 30 may be provided on an end wall at one end of the tubular wall of the rotor body 14.

[0049] A component of the position encoder 35, such as the discrete magnets or optical markings previously described, may be mounted of the rotor end wall.

[0050] Both the rotor and stator may be made of polymer materials with a Young’s modulus in a range of 200 megapascals to 3 gigapascals, such polymers including fluoropolymers (PTFE, PCTFE ...) or high-performance plastics such as Polyetheretherketone (PEEK).

[0051] In preferred embodiments the rotor is made from a polymer selected from PTFE, UHMW- PE, or compounds based on these materials, whereas the stator is preferably made from a polymer selected from PEEK, PCTFE, PVDF, or compounds based on these materials. In embodiments, the stator may also be made of non-polymer materials including metals, in which case the elastic compressibility is provided by the rotor body made of a polymer.

[0052] Advantageously, embodiments of the invention provide a very high density of fluidic ports and fluidic interconnections in a compact arrangement, with the ability to create sequences of different fluidic interconnections when rotating the rotor that also allows to perform special functions such as the generation of droplet sequences with the volume of each droplet being controlled via the rotation speed of the rotor and the aspiration of the pumping system. The sequences of droplets can be generated in a repeatable manner for each full rotation of the rotor. The control over the rotation speed of the rotor and over the negative pressure generated by the pumping system enables fine tuning of the droplet sequence, such adjustment being critical in microfluidics application. Additionally, some ports can be connected to air, oil or a buffer to separate each droplet.

[0053] List of references

[0054] Microfluidic distribution system 1

[0055] Microfluidic rotary valve 2

[0056] Stator 4

[0057] Stator body 10

[0058] Tubular wall

[0059] Wall thickness TS

[0060] Rotor receiving cavity 24

[0061] Inner diameter DSi

[0062] Axial positioning shoulder 26

[0063] Inner bearing surface 16

[0064] Ports 12

[0065] Rotor 6

[0066] Rotor body 14 Tubular wall

[0067] Outer diameter DRo

[0068] Inner diameter DRi

[0069] Wall thickness TR Centre bore 22

[0070] Outer bearing surface 18

[0071] Bearing surface length BL Channels 20

[0072] Grooves Axial end shoulder 28

[0073] Coupling 30

[0074] Actuator 8

[0075] Motor (Stepping)

[0076] Shaft 32

[0077] Coupling 34

[0078] Position encoder

[0079] Pumps

Claims

Claims1. A micro fluidic rotary valve (2) comprising a stator (4), a rotor (6), and an actuator (8) coupled to the rotor for turning the rotor (6) relative to the stator (4), the stator (4) comprising a stator body having a rotor receiving cavity (24) defining an inner bearing surface (16), and a plurality of ports (12) connectable to fluid conduits for the supply or extraction of fluids, the ports (12) having orifices that open onto the inner bearing surface (16), the rotor comprising a rotor body (14) having an outer bearing surface (18) in contact with the stator inner bearing surface (16), the outer bearing surface (18) of the rotor body (14) comprising a plurality of groove channels (20) distributed around the circumference of the outer bearing surface (18) each groove channel (20) interconnecting at least two ports of said plurality of ports forming a pair of ports at a specific angular orientation of the rotor relative to the stator, different groove channels (20) interconnecting different pairs of ports of said plurality of ports at different specific angular orientations of the rotor relative to the stator.

2. The micro fluidic rotary valve of claim 1 wherein the rotor body (14) has an uncompressed outer diameter DRo) of the outer bearing surface (18), and the stator body (10) has an inner bearing surface (16) with inner diameter {DSi) in an uncompressed state, said outer diameter {DRo being greater than said inner diameter DSi) such that the outer bearing surface (18) is elastically biased against the inner bearing surface (16), at least one of the rotor and stator being elastically compressible or expandable.

3. The micro fluidic rotary valve of the preceding claim wherein the degree of elastic compression of the rotor body relative to the stator body is in a range of 0.5 to 5%, preferably in a range of 1.5 to 2.5% relative to said outer diameter.

4. The micro fluidic rotary valve according to either of the two directly preceding claims wherein the rotor body (14) comprises a tubular wall with a center bore (22).

5. The micro fluidic rotary valve according to the preceding claim wherein the rotor body (14) is elastically compressed to provide over 90% of the compression rate.

6. The micro fluidic rotary valve according to either of the two directly preceding claims wherein a wall thickness {TR) of the rotor body tubular wall is in a range of 5 to 40% of the outer bearing surface diameter {0.05 DRo < TR < 0.4 DRo), preferably in a range of 5% to 20% {0.1 DRo < TR < 0.2 DRo).

7. The micro fluidic rotary valve according to any preceding claim wherein the channel grooves (20) have a depth in a range of 0.1 to 2 mm, preferably in a range of 0.2 to 1 mm, and a width between 0.1 to 2 mm, preferably in a range of 0.2 to 1 mm, the outer bearing surface (18) of the rotor body having a diameter in a range of 5 to 60 mm.

8. The micro fluidic rotary valve according to any preceding claim wherein the stator comprises between 5 to 100 ports, for instance between 8 to 20 ports.

9. The micro fluidic rotary valve according to any preceding claim wherein the rotor body (14) of the rotor (6) is made from a polymer selected from a group consisting of PTFE, UHMW-PE, or compounds based on these materials and the stator is made of a polymer selected from a group of materials consisting of PEEK, PCTFE, PVDF, or compounds based on these materials.

10. The micro fluidic rotary valve according to any preceding claim wherein the rotor body (14) is injection molded and the stator body (10) is injection molded.11 . The micro fluidic rotary valve according to any preceding claim wherein the actuator (8) comprises a position encoder (35) having discrete positioning elements mounted on an end wall of the rotor body (14), the discrete elements comprising magnets, the position encoder further comprising a magnetic field sensor, for instance a Hall sensor mounted on the stator configured to detect the discrete positioning elements and determine therefrom the angular position and displacement of the rotor relative to the stator.

12. The micro fluidic rotary valve according to any preceding claim wherein the ports (12) are arranged along an axial band of an outer surface of the stator.

13. The micro fluidic rotary valve according to any preceding claim wherein the rotor body comprises an axial end shoulder (28) abutting against an axial positioning shoulder (26) at an end of the rotor receiving cavity (24) to position the rotor axially with respect to the stator.

14. The micro fluidic rotary valve according to any preceding claim configured for the generation of a sequence of droplets output at different ports during rotation of the rotor body.

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