Microdosing apparatus and method for dosed dispensing of liquids

• US 20060147313A1
• Filed: 02/14/2006
• Published: 07/06/2006
• Est. Priority Date: 08/14/2003
• Status: Active Grant

• Current Assignee: BioFluidix GmbH
• Original Assignee: Roland Zengerle and Hermann Sandmaier
• Inventors: Koltay, Peter, Birkle, Gerhard, Zengerle, Roland, Streule, Wolfgang
• Granted Patent: US 7,900,850 B2
• Time in Patent Office: Days
• US Class Current: 417/53
• CPC Class Codes: B01L 2300/0838 Capillaries
• CPC Class Codes: B01L 2300/123 Flexible; Elastomeric
• CPC Class Codes: B01L 2400/0481 squeezing of channels or chambers
• CPC Class Codes: B01L 3/0268 using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
• CPC Class Codes: Y10S 239/12 Flexible outlets

Abstract

A microdosing apparatus comprises a fluid conduit having a flexible tube with a first end for connecting to a fluid reservoir and a second end where an outlet opening is located. An actuating device with a displacer with adjustable hub is provided, by which the volume of a portion of the flexible hub can be changed to thereby dispense liquid as free flying droplets or as free flying jet at the outlet opening by moving the displacer between a first end position and a second end position, whereby the tube is partly compressed in the first or the second end position. In other words, a microdosing apparatus comprises fluid conduit having a portion along which a cross section of the fluid conduit is variable by an actuating device to effect a change of the volume of the fluid conduit. A ratio of a fluidic impedance between the position of the actuating device and the outlet opening to a fluidic impedance between a first end of the fluid conduit and the position of the actuating device is variable by changing the position of the actuating device, so that a dosing volume dispensed at the outlet opening is variable thereby by at least 10%.

Claims

1. A microdosing apparatus, comprising:

a fluid conduit having a flexible tube with a first end for connecting to a liquid reservoir and a second end where an outlet opening is located; and

an actuating device having a displacer with adjustable hub, by which the volume of a portion of the flexible tube can be changed, to thereby dispense liquid as free flying droplets or as free flying jet at the outlet opening by moving the displacer between a first end position and a second end position, wherein the tube is partly compressed at least in the first end position or the second end position.

2. The microdosing apparatus according to claim 1, wherein the flexible tube consists of polyimide.

3. The microdosing apparatus according to claim 1, wherein the flexible tube has at least one portion wherein the same has no erratic cross section changes, so that by changing the position of the actuating device along the portion, a ratio of a fluidic impedance between the position of the actuating device and the outlet opening to a fluidic impedance between the first end and the position of the actuating device is variable, so that the dosing volume output at the outlet opening is variable by at least 10%.

4. The microdosing apparatus according to claim 1, wherein the tube can be compressed across a predetermined length by the displacer in order to effect the volume change of the tube.

5. The microdosing apparatus according to claim 4, wherein the displacer has a form to effect an axially asymmetric volume change with regard to the tube.

6. The microdosing apparatus according to claim 1, further having a holder for holding the actuating device at one or the position along the tube.

7. The microdosing apparatus according to claim 1 having a biasing device to bias the tube into a fully or partly compressed state through the displacer.

8. The microdosing apparatus according to claim 7, wherein the actuating device has an actuator, which is disposed to move the displacer against the bias of the biasing device.

13. The microdosing apparatus according to claim 1, wherein the fluid conduit has no erratic cross section changes between the first end and the outlet opening in the resting state.

14. The microdosing apparatus according to claim 1, wherein the fluid conduit has a substantially constant cross section between the first end and the outlet opening in the resting position.

15. The microdosing apparatus according to claim 1, further having a provider for providing the fluid conduit with a pressure difference.

16. The microdosing apparatus according to claim 1, wherein the fluid conduit has such a cross section area that a liquid to be dosed can be moved through the same by capillary forces.

17. The microdosing apparatus according to claim 1, having a plurality of respective fluid conduits, so that several equal or different liquids can be dispensed simultaneously or successively.

18. The microdosing apparatus according to claim 17, having an actuating device for simultaneously effecting the volume change of the plurality of fluid conduits.

19. The microdosing apparatus according to claim 18, wherein the actuating device is a common displacer.

9. A microdosing apparatus, comprising:

a fluid conduit with a first end for connecting to a fluid reservoir and a second end where an outlet opening is located, the fluid conduit having a portion along which a cross section of the fluid conduit can be varied to effect a change of the volume of the fluid conduit;

an actuating device disposed at a position along the portion of the fluid conduit for effecting a change of the volume of the fluid conduit to thereby dispense liquid as free flying droplets or free flying jet from the outlet opening,

wherein a ratio of a fluidic impedance between the position of the actuating device and the outlet opening to a fluidic impedance between the first end and the fluid conduit and the position of the actuating device is variable by changing the position of the actuating device, so that a dosing volume dispensed at the outlet opening is thereby variable by at least 10%.

10. The microdosing apparatus according to claim 9, wherein the actuating device has a displacer by which the portion of the fluid conduit can be compressed across a predetermined length to effect the volume change of the portion of the fluid conduit.

11. The microdosing apparatus according to claim 10, wherein the displacer has a form to effect an axially asymmetric volume change with regard to the portion of the fluid conduit.

12. The microdosing apparatus according to claim 9, further having a holder for holding the actuating device at the position along the portion of the fluid conduit.

20. A method for dosed dispensing of liquids, comprising the steps of:

filling a fluid conduit having a flexible tube with a liquid to be dosed;

effecting a volume change of a portion of the flexible tube by a displacer with adjustable hub, to thereby dispense liquid as free flying droplets or as free flying jet at an outlet opening of the fluid conduit by moving the displacer between a first end position and a second end position, wherein the tube is partly compressed at least in the first end position or the second end position.

21. The method according to claim 20, further comprising the step of providing a displacer at a position along the tube, by which the tube can be compressed across a predetermined length to effect the volume change of the portion of the same.

22. The method according to claim 21, wherein the fluid conduit has a first end connected to a fluid reservoir and a second end where the outlet opening is located, further comprising the step of:

selecting the position of the displacer along the tube to adjust a ratio of a fluidic impedance between the position of the displacer and the outlet opening to a fluidic impedance between the first end and the position of the actuating device, to thereby dispense a desired dosing volume at the outlet opening by effecting the volume change.

23. The method according to claim 21, further comprising a step of selecting a displacer with a length axial with regard to the flexible tube, to effect the volume change by using the displacer and to dispense a desired dosing volume at the outlet opening.

24. The method according to claim 22, wherein in the step of effecting the volume change, a volume change axially asymmetric with regard to the flexible tube is performed to effect a fluid flow with a preferred direction towards the outlet opening in the fluid conduit.

25. The method according to claim 20, further comprising a step of providing the fluid conduit with a static pressure.

26. The method according to claim 25, wherein the static pressure with regard to the outlet end is an overpressure to effect a fluid flow with a preferred direction towards the outlet opening when effecting the volume change in the fluid conduit, and/or to support a refill after a dosing process.

27. The method according to claim 25, wherein the static pressure with regard to the outlet end is a subpressure to prevent leaking of liquid from the outlet end when no volume change is effected.

28. The method according to claim 20, further comprising a step of reversing the volume change after the step of effecting a volume change, so that the tube returns to the initial state, wherein during this step a capillary refill of the fluid conduit takes place.

29. A method for adjusting a desired dosing volume during a dosing process by using a microdosing apparatus comprising:

a fluid conduit with a first end for connecting to a fluid reservoir and a second end where an outlet opening is located, the fluid conduit having a portion along which a cross section of the fluid conduit can be varied to effect a change of the volume of the fluid conduit;

an actuating device disposed at a position along the portion of the fluid conduit for effecting a change of the volume of the fluid conduit to thereby dispense liquid as free flying droplets or free flying jet from the outlet opening,

wherein a ratio of a fluidic impedance between the position of the actuating device and the outlet opening to a fluidic impedance between the first end and the fluid conduit and the position of the actuating device is variable by changing the position of the actuating device, so that a dosing volume dispensed at the outlet opening is thereby variable by at least 10%;

the method comprising the step of;

disposing the actuating device at a predetermined position along the portion of the fluid conduit, so that due to the resulting ratio of fluidic impedances in the step of effecting a change of the volume of the fluid conduit, a desired dosing volume can be dispensed at the outlet opening.

30. A method for adjusting a desired dosing volume in a dosing process by using a microdosing apparatus comprising:

a fluid conduit with a first end for connecting to a fluid reservoir and a second end where an outlet opening is located, the fluid conduit having a portion along which a cross section of the fluid conduit can be varied to effect a change of the volume of the fluid conduit;

an actuating device disposed at a position along the portion of the fluid conduit for effecting a change of the volume of the fluid conduit to thereby dispense liquid as free flying droplets or free flying jet from the outlet opening,

wherein a ratio of a fluidic impedance between the position of the actuating device and the outlet opening to a fluidic impedance between the first end and the fluid conduit and the position of the actuating device is variable by changing the position of the actuating device, so that a dosing volume dispensed at the outlet opening is thereby variable by at least 10%;

wherein the actuating device has a displacer by which the portion of the fluid conduit can be compressed across a predetermined length to effect the volume change of the portion of the fluid conduit;

the method comprising the step of;

selecting a displacer with an axial length with regard to the portion of the fluid conduit, which is adapted to allow dispensing of a desired dosing volume at the outlet opening in the step of effecting a change of the volume of the fluid conduit.