High performance, low volume, non-contact liquid dispensing apparatus and method

• US 20030170903A1
• Filed: 01/27/2003
• Published: 09/11/2003
• Est. Priority Date: 01/25/2002
• Status: Active Grant

• Current Assignee: BioNex Solutions, Inc.
• Original Assignee: Innovadyne Technologies, Inc.
• Inventors: Johnson, James E., Picha, Neil R., Storms, Craig M., Martin, David A.
• Granted Patent: US 7,169,616 B2
• Time in Patent Office: Days
• US Class Current: 436/100
• CPC Class Codes: B01L 2200/143 Quality control, feedback systems
• CPC Class Codes: B01L 2200/148 Specific details about calibrations
• CPC Class Codes: B01L 2300/14 Means for pressure control
• CPC Class Codes: B01L 2400/02 Drop detachment mechanisms of single droplets from nozzles or pins
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 2400/06 Valves, specific forms thereof
• CPC Class Codes: B01L 2400/0633 with moving parts
• CPC Class Codes: B01L 2400/0666 Solenoid valves
• CPC Class Codes: B01L 3/021 Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
• CPC Class Codes: B01L 3/0268 using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
• CPC Class Codes: G01N 2035/00237 Handling microquantities of analyte, e.g. microvalves, capillary networks
• CPC Class Codes: G01N 2035/1041 Ink-jet like dispensers
• CPC Class Codes: G01N 2035/1044 Using pneumatic means
• CPC Class Codes: G01N 35/00594 Quality control, including calibration or testing of components of the analyser
• CPC Class Codes: G01N 35/00712 Automatic status testing, e.g. at start-up or periodic
• CPC Class Codes: G01N 35/1002 Reagent dispensers
• CPC Class Codes: G01N 35/1016 Control of the volume dispensed or introduced
• CPC Class Codes: G01N 35/1065 Multiple transfer devices
• CPC Class Codes: Y10T 137/3003 Fluid separating traps or vents
• CPC Class Codes: Y10T 436/15 Inorganic acid or base [e.g. , hcl, sulfuric acid, etc. ]
• CPC Class Codes: Y10T 436/2575 : Volumetric liquid transfer

Abstract

An apparatus and method for delivering repetitive, precision, low volume liquid dispensing from a dispensing orifice of a non-contact liquid dispensing apparatus. An elongated communication passageway of the dispensing apparatus is defined by interior walls having one end in fluid communication with a system fluid reservoir and an opposite end terminating at the dispensing orifice. A system fluid is placed in the communication passageway extending substantially continuously from the system fluid reservoir to the dispensing orifice. A relatively small volume of gaseous fluid is aspirated through the dispensing orifice, and into the communication passageway in a manner such that the gaseous fluid extends substantially continuously across the transverse cross-sectional dimension of the communication passageway. Subsequently, a dispensing liquid is aspirated through the dispensing orifice and into the communication passageway in a manner such that the relatively small volume of aspirated gaseous fluid forms a minute, unitary air gap fully enclosed between the interior walls of the communication passageway and a liquid interface between the system fluid and the dispensing liquid contained in the communication passageway. This minute air gap substantially prevents dispersion and dilution therebetween at the liquid interface. To effect dispensing, a rapid pressure pulse with a predetermined pulse width is applied to the system fluid upstream from the minute air gap, causing the pressure pulse to traverse the minute air gap to the dispensing liquid without substantial fluid compression of the minute air gap. This enables substantially accurate, relatively small volume, non-contact liquid dispensing of the dispensing liquid from the dispensing orifice.

Claims

1. A method for delivering repetitive, precision, low volume liquid dispensing from a dispensing orifice of a non-contact liquid dispensing apparatus providing interior walls defining an elongated communication passageway having one end in fluid communication with a system fluid reservoir and an opposite end terminating at the dispensing orifice, said method comprising:

placing a system fluid in the communication passageway extending substantially continuously from the system fluid reservoir to the dispensing orifice;

aspirating a relatively small volume of gaseous fluid through the dispensing orifice and into the communication passageway in a manner such that said gaseous fluid extends substantially continuously across the transverse cross-sectional dimension of the communication passageway;

aspirating a dispensing liquid through the dispensing orifice and into the communication passageway in a manner such that the relatively small volume of aspirated gaseous fluid forms a minute, unitary air gap fully enclosed between the interior walls of the communication passageway and a liquid interface between the system fluid and the dispensing liquid contained in the communication passageway to substantially prevent dispersion and dilution therebetween at said liquid interface; and

applying a rapid pressure pulse with a predetermined pulse width to the system fluid upstream from said minute air gap, causing said pressure pulse to traverse said minute air gap to the dispensing liquid without substantial fluid compression of said minute air gap, for substantially accurate, relatively small volume, non-contact liquid dispensing of the dispensing liquid from the dispensing orifice.

2. The method according to claim 1, wherein

said applying a rapid pressure pulse includes:

pressurizing the system fluid with a substantially constant back pressure, and

actuating a rapid actuation dispensing valve in fluid communication with said communication passageway, downstream from the system fluid reservoir and upstream from said air gap, between a closed condition and an opened condition, providing fluid communication between the communication passageway and the system fluid reservoir.

3. The method according to claim 2, wherein

said back pressure is in the range of about 2.0 psi to about 15.0 psi.

4. The method according to claim 3, wherein

said back pressure is about 8.0 psi.

5. The method according to claim 2, wherein

said pressurizing the system fluid forming a substantially constant back pressure at the system fluid reservoir with a pressurizing gas.

6. The method according to claim 5, further including:

selecting a pressurizing gas that suppresses in-gassing, and is substantially insoluble to the system fluid.

7. The method according to claim 6, wherein

said selecting a pressurizing gas includes selecting helium.

8. The method according to claim 6, further including:

selecting elongated pressure tubing, defining the communication passageway, that is chemically inert to biological fluids and commonly used solvents including DMSO, THF, alcohols, aldehydes, ketones, halogenated hydrocarbons, aliphatic hydrocarbons, acids and bases used in the life sciences and diagnostic fields.

9. The method according to claim 2, further including:

maintaining the air gap greater than about 1.0 to about 3.0 inches from said dispensing valve.

10. The method according to claim 2, wherein

said actuating a rapid actuation dispensing valve maintaining the control valve in the opened condition for a predetermined duration correlating to said predetermined pressure pulse.

11. The method according to claim 1, wherein

aspirating a relatively small volume of gaseous fluid includes actuating a metered analytical aspiration device, fluidly coupled to the communication passageway, a metered amount to aspirate said gaseous fluid.

12. The method according to claim 11, wherein

said actuating the metered analytical device is performed by stepping a metered analytical syringe.

13. The method according to claim 11, wherein

said actuating an analytical aspiration device includes aspirating said relatively small volume of gaseous fluid in the range of about 150 nl to about 5 μ

l.

14. The method according to claim 13, wherein

said actuating an analytical aspiration device includes aspirating said relatively small volume of gaseous fluid in the range of about 250 nl to about 2 μ

l.

15. The method according to claim 1, further including:

after the aspirating a dispensing liquid and before the applying a rapid pressure pulse to the system fluid, switching the communication passageway from an aspiration source to a dispensing source.

16. The method according to claim 15, wherein

said switching the communication passageway is performed by positioning a switching valve device from an aspiration condition, fluidly coupling the aspiration actuator to the communication passageway, to a dispensing position, fluidly coupling a dispensing actuator to the communication passageway and fluidly decoupling the aspiration actuator from the communication passageway.

17. The method according to claim 16, wherein

said switching valve device is provided by a shear valve having a rotor face and a stator face, and

said switching the valve device to one of the aspiration condition and the dispensing condition includes slideably and rotatably engaging a rotor face of the valve device against the stator face about a longitudinal axis of said rotor face at a stator-rotor interface, to fluidly couple the aspiration actuator to the communication passageway and fluidly couple the dispensing actuator to the communication passageway, respectively.

18. The method according to claim 2, wherein

said placing a system fluid in the communication passageway includes urging the liquid distal end of the system fluid contained in the communication passageway toward the dispensing orifice until expulsion or near expulsion of the system fluid from the dispensing orifice.

19. The method according to claim 18, wherein

said urging the liquid end is performed by actuating a dispensing valve from the closed condition to the opened condition.

20. The method according to claim 2, further including:

before the aspirating a relatively small volume of gaseous fluid, purging trapped gas contained in the dispensing valve.

21. The method according to claim 20, wherein

said purging trapped gas includes rapidly actuating the dispensing valve between the closed condition and the opened condition to purge trapped gases from the dispensing valve.

22. The method according to claim 21, wherein

said rapidly actuating the dispensing valve is performed by actuating the dispensing valve at a discrete frequency for a predetermined period of time.

23. The method according to claim 22, wherein

said actuating the dispensing valve at said discrete frequency is performed at a set number of said predetermined periods of time.

24. The method according to claim 22, wherein

said rapidly actuating a dispensing valve is performed by varying the actuation frequency of the dispensing valve from said discrete frequency.

25. The method according to claim 24, wherein

said varying the actuation frequency of the dispensing valve is performed at a plurality of set discrete frequencies, each actuation at one of the discrete frequencies being for a respective predetermined period of time.

26. The method according to claim 25, wherein

said plurality of discrete frequencies are in the range of about 1 Hz to about 1750 Hz.

27. The method according to claim 26 wherein

said plurality of discrete frequencies are in the range of about 10 Hz to about 420 Hz.

28. The method according to claim 25, further including:

actuating the dispensing valve at each discrete frequency for said respective predetermined period of time a respective set number of times.

29. The method according to claim 25, wherein

said varying the actuation frequency is performed by a ramped frequency sweep, incrementally increasing the actuation frequency at said discrete frequencies.

30. The method according to claim 29, wherein

said incrementally increasing the actuation frequency is performed in the range from about 10 Hz to about 420 Hz.

31. The method according to claim 25, wherein

said varying the actuation frequency is performed by a ramped frequency sweep, incrementally decreasing the actuation frequency at said discrete frequencies.

32. The method according to claim 1, further including:

providing substantially smooth diametric transitions in said communication passageway from the dispensing valve to the dispensing orifice to facilitate the integrity of said minute air gap moving through the communication passageway during the applying a rapid pressure pulse.

33. A method of purging trapped gas in a system fluid contained in an actuation valve fluidly coupled along a communication passageway of an elongated, flexible pressure tube, one end of said communication passageway being in fluid communication with a system fluid reservoir providing the system fluid while an opposite end of the communication passageway being in fluid communication with a dispensing orifice, said method comprising:

flowing the system fluid through the actuation valve and into said communication passageway between the one end of the pressure tube and the dispensing orifice such that said actuation valve and said communication passageway are converted from a dry state to a hydraulic state;

rapidly actuating the actuation valve between a closed condition, preventing flow of said system fluid through said actuation valve from said system fluid reservoir to the dispensing orifice, and an opened condition, enabling fluid flow of the system fluid through said communication passageway, at at least two different discrete frequencies each for a respective predetermined period of time in a manner purging and expelling trapped gases in said actuation valve and corresponding communication passageway through the dispensing orifice.

34. The method according to claim 33, further including:

pressurizing the system fluid with a substantially constant back pressure to provide a substantially constant pressure head at the actuation valve.

35. The method according to claim 33, wherein

said rapidly actuating the actuation valve at the respective discrete frequencies for said respective predetermined periods of time is performed a set number of times.

36. The method according to claim 34, wherein

said rapidly actuating the actuation valve is performed by varying the actuation frequency at a plurality of set discrete frequencies, each actuation at one of the discrete frequencies being for a respective predetermined period of time.

37. The method according to claim 34, wherein

said plurality of discrete frequencies are in the range of about 1 Hz to about 1750 Hz.

38. The method according to claim 37 wherein

said plurality of discrete frequencies are in the range of about 10 Hz to about 420 Hz.

39. The method according to claim 36, further including:

actuating the actuation valve at each discrete frequency for said respective predetermined period of time a respective set number of times.

40. The method according to claim 36, wherein

said varying the actuation frequency is performed by a ramped frequency sweep, incrementally increasing the actuation frequency at said discrete frequencies.

41. The method according to claim 40, wherein

said incrementally increasing the actuation frequency is performed in the range from about 10 Hz to about 420 Hz.

42. The method according to claim 36, wherein

said varying the actuation frequency is performed by a ramped frequency sweep, incrementally decreasing the actuation frequency at said discrete frequencies.

43. The method according to claim 34, wherein

said back pressure is in the range of about 2.0 psi to about 15.0 psi.

44. The method according to claim 43, wherein

said back pressure is about 8.0 psi.

45. The method according to claim 43, wherein

said pressurizing the system fluid forming a substantially constant back pressure at the system fluid reservoir with a pressurizing gas.

46. The method according to claim 33, wherein

said pressurizing the system fluid is performed before the flowing of the system fluid into said communication passageway.

47. A method of simultaneous purging trapped gas from system fluid contained in a plurality of actuation valves fluidly coupled along respective communication passageways of a corresponding elongated, flexible pressure tubes of a non-contact, liquid dispensing system, one end of each said pressure tube being in flow communication with a system fluid reservoir providing the system fluid while an opposite end thereof being in fluid communication with a respective dispensing orifice, said method comprising:

(a) simultaneously flowing the system fluid into each respective communication passageway between the one end of each respective pressure tube and the respective dispensing orifice thereof such that each actuation valve and each said communication passageway is converted from a dry state to a hydraulic state;

(b) simultaneously rapidly actuating each actuation valve between a respective closed condition, preventing flow of said system fluid therethrough from said system fluid reservoir to the respective dispensing orifice thereof, and a respective opened condition, enabling fluid flow of the system fluid through each said communication passageway, at a discrete actuation frequency for a respective predetermined period of time such that trapped gases contained in each respective actuation valve and each respective communication passageway are purged and expelled through the respective dispensing orifice.

48. The method according to claim 47, further including:

pressurizing the system fluid in said system fluid reservoir with a pressurizing gas to form a substantially constant pressure head at each actuation valve.

49. The method according to claim 47, wherein

said simultaneously rapidly actuating each actuation valve for said respective predetermined period of time are each performed a set number of times.

50. The method according to claim 47, wherein

said simultaneously rapidly actuating each actuation valve is performed by varying the actuation frequency at a plurality of set discrete frequencies, each actuation at one of the discrete frequencies being for a respective predetermined period of time.

51. The method according to claim 50 wherein

said plurality of discrete frequencies are in the range of about 10 Hz to about 420 Hz.

52. The method according to claim 50, further including:

actuating each actuation valve at each discrete frequency for said respective predetermined period of time a respective set number of times.

53. The method according to claim 52, wherein

said varying the actuation frequency is performed by a ramped frequency sweep, incrementally increasing the actuation frequency at said discrete frequencies.

54. The method according to claim 53, wherein

said incrementally increasing the actuation frequency is performed in the range from about 10 Hz to about 420 Hz.

55. The method according to claim 50, wherein

said varying the actuation frequency is performed by a ramped frequency sweep, incrementally decreasing the actuation frequency at said discrete frequencies.

56. The method according to claim 48, wherein

said pressurizing the system fluid is performed by supplying the pressurizing gas in the range of about 2.0 psi to about 15.0 psi.

57. The method according to claim 56, wherein

said pressurizing the system fluid is performed by supplying the pressurizing gas in the range of about 8.0 psi.

58. The method according to claim 56, further including:

selecting a pressurizing gas that suppresses in-gassing, and is substantially insoluble to the system fluid.

59. The method according to claim 58, wherein

said selecting a pressurizing gas includes selecting helium.

60. The method according to claim 47, further including:

(c) actuating each said actuation valve from the closed condition to the opened condition and back to the closed condition for substantially the same time period to respectively dispense system fluid from each dispensing orifice of the respective pressure tube;

(d) measuring the volume of system fluid dispensed from each dispensing orifice;

(e) calculating the mean variance of the measured volumes;

(f) for each pressure tube having a measured volume of system fluid varying from the mean variance by more than a predetermined percentage, repeating event (b).

61. The method according to claim 60, further including:

repeating events (c)-(f) until the respective dispense volume for each pressure tube does not vary from the mean variance by more than the predetermined percentage.

62. The method according to claim 60, wherein

said predetermined percentage is in the range of about 3% to about 7%.

63. The method according to claim 62, wherein

said predetermined percentage is in the range of about 5%.