Method of purging trapped gas from a system fluid contained in an actuation valve

• US 7,169,616 B2
• Filed: 01/27/2003
• Issued: 01/30/2007
• 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.
• Primary Examiner(s): Gordon; Brian R.
• Application Number:
  US10/353,824
• Publication Number:
  US 20030170903A1
• Time in Patent Office: 1,464 Days
• Field of Search: 422/100, 422/103, 436/180, 137/171, 137/197, 251/129.05
• US Class Current: 436/180
• 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 of purging trapped gas from a system fluid contained in one or more interior areas of an actuation valve that selectively fluidly inter-couples a fluid communication line to a pressurized system fluid reservoir providing the system fluid, said fluid communication line defining a communication passageway extending from a dispensing orifice thereof to the actuation valve, said method comprising:

pressurizing the system fluid in the system fluid reservoir with a pressurized gas;

priming the actuation valve and the fluid communication line by initially flowing the system fluid, via said pressurized gas, through the actuation valve and into said communication passageway for dispensing through the dispensing orifice such that said actuation valve and said communication passageway are converted from a generally dry state to a hydraulic state; and

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 and dispensing of the system fluid through said dispensing orifice, at at least two different discrete actuation frequencies each for a respective predetermined period of time in a manner purging and expelling trapped gases contained in the areas of said actuation valve.

2. The method according to claim 1, wherein

said pressurizing the system fluid includes providing a substantially constant gas pressure to maintain a substantially constant pressure head at the actuation valve.

3. The method according to claim 1, 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.

4. The method according to claim 2, 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.

5. The method according to claim 2, wherein

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

6. The method according to claim 5 wherein

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

7. The method according to claim 4, further including:

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

8. The method according to claim 4, wherein

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

9. The method according to claim 8, wherein

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

10. The method according to claim 4, wherein

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

11. The method according to claim 2, wherein

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

12. The method according to claim 11, wherein

said gas pressure is about 8.0 psi.

13. The method according to claim 11, wherein

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

14. The method according to claim 13, wherein

said pressurizing gas is helium.

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

after rapidly actuating the actuation valve, purging the actuation valve and the communication line of the expelled and purged trapped gases by flowing the system fluid, via said pressurized gas, through the actuation valve and out the dispensing orifice of the communication line.

15. A method of simultaneous purging trapped gas from system fluid contained in respective interior areas of a plurality of respective actuation valves, each selectively fluidly inter-couples a respective fluid communication line to a pressurized system fluid reservoir providing the system fluid, each respective fluid communication line defines a respective communication passageway extending from a respective dispensing orifice thereof to the respective actuation valve, said method comprising:

(a) pressurizing the system fluid of the system fluid reservoir with a pressurized gas;

(b) priming each actuation valve and respective communication line by simultaneously flowing the system fluid, via said pressurized gas, through each actuation valve and into each respective communication passageway for dispensing through each respective dispensing orifice thereof such that each actuation valve and each said communication passageway is converted from a generally dry state to a hydraulic state; and

(c) 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 and dispensing of the system fluid through each respective dispensing orifice, at a discrete actuation frequency for a respective predetermined period of time such that trapped gases contained in the interior areas of each respective actuation valve are purged and expelled therefrom.

16. The method according to claim 15, wherein

said pressurizing the system fluid includes providing a substantially constant gas pressure to said system fluid reservoir to maintain a substantially constant pressure head at each actuation valve.

17. The method according to claim 15, wherein

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

18. The method according to claim 15, 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.

19. The method according to claim 18 wherein

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

20. The method according to claim 18, further including:

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

21. The method according to claim 20, wherein

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

22. The method according to claim 21, wherein

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

23. The method according to claim 18, wherein

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

24. The method according to claim 16, 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.

25. The method according to claim 24, wherein

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

26. The method according to claim 24, further including:

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

27. The method according to claim 26, wherein

said selecting a pressurizing gas includes selecting helium.

28. The method according to claim 15, 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 communication line;

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

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

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

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

repeating events (c)–

(f) until the respective dispense volume for each communication line does not vary from the mean variance by more than the predetermined percentage.

30. The method according to claim 28, wherein

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

31. The method according to claim 30, wherein

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

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

after simultaneously rapidly actuating each actuation valve, simultaneously purging each respective actuation valve and the corresponding communication line of the expelled and purged trapped gases by simultaneously flowing the system fluid, via said pressurized gas, through each respective actuation valve and out the corresponding dispensing orifice of the respective communication line.

34. A method of purging trapped gas from a system fluid contained in one or more interior areas of an actuation valve that selectively fluidly inter-couples a fluid communication line to a pressurized system fluid reservoir providing the system fluid, said fluid communication line defining a communication passageway extending from a dispensing orifice thereof to the actuation valve, said method comprising:

pressurizing the system fluid in the system fluid reservoir with a pressurized gas;

priming the actuation valve and the fluid communication line by initially flowing the system fluid, via said pressurized gas, through the actuation valve and into the communication passageway for dispensing through the dispensing orifice such that said actuation valve and said communication passageway are converted from a generally dry state to a hydraulic state;

rapidly actuating the actuation valve between a closed condition and an opened condition at a discrete actuation frequency for a predetermined period of time such that the trapped gases contained in the areas of said actuation valve are purged and expelled therefrom; and

after rapidly actuating the actuation valve, purging the actuation valve and the communication line of the expelled and purged trapped gases by flowing the system fluid, via said pressurized gas, through the actuation valve, the communication passageway and out the dispensing orifice of the communication line.

35. The method according to claim 34, wherein

said pressurizing the system fluid includes providing a substantially constant gas pressure to maintain a substantially constant pressure head at the actuation valve.

36. The method according to claim 35, 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 36, wherein

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

38. 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.

39. The method according to claim 38, wherein

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

40. 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.

41. The method according to claim 34, wherein

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

42. The method according to claim 34, wherein

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