SYSTEM AND METHOD FOR REPETITIVE, HIGH PERFORMANCE, LOW VOLUME, NON-CONTACT LIQUID DISPENSING

• US 20070155019A1
• Filed: 01/26/2007
• Published: 07/05/2007
• Est. Priority Date: 01/25/2002
• Status: Abandoned Application

• Current Assignee: Innovadyne Technologies, Inc.
• Original Assignee: Innovadyne Technologies, Inc.
• Inventors: Martin, David, Johnson, James, Picha, Neil, Storms, Craig
• Application Number:
  US11/627,830
• Publication Number:
  US 20070155019A1
• Time in Patent Office: Days
• 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. The system fluid reservoir is pressurized at a substantially constant back pressure, with a pressurizing gas, preferably helium, that suppresses in-gassing, and that is substantially insoluble to the system liquid. A dispensing liquid is aspirated through the dispensing orifice and into the communication passageway substantially to an interface region with the system fluid contained in the communication passageway. To effect dispensing, a rapid pressure pulse with a predetermined pulse width is applied to the system fluid, enabling 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 having an elongated communication passageway with one end in fluid communication with a system reservoir of system liquid and an opposite end terminating at the dispensing orifice, said method comprising:

pressurizing the system liquid in system reservoir, at a substantially constant back pressure, with a pressurizing gas that suppresses in-gassing, and that is substantially insoluble to the system liquid;

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

aspirating a dispensing liquid in the communication passageway in a manner extending from the dispensing orifice substantially to an interface region with the system fluid contained in the communication passageway; and

applying a rapid pressure pulse with a predetermined pulse width to the pressurized system liquid causing 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 pressurizing gas is comprised of helium.

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 applying a rapid pressure pulse includes actuating a rapid actuation dispensing valve in fluid communication with said communication passageway, downstream from the system liquid 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 liquid reservoir.

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

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

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

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

8. The method according to claim 6, wherein

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

9. The method according to claim 6, wherein

aspirating said 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.

10. The method according to claim 9, wherein

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

11. The method according to claim 10, 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.

12. 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 250 nl to about 2 μ

l.

13. 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 liquid, switching the communication passageway from an aspiration source to a dispensing source.

14. The method according to claim 13, wherein

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

15. The method according to claim 14, 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.

16. The method according to claim 2, wherein

said placing the system liquid in the communication passageway includes flowing the system liquid contained in the communication passageway toward the dispensing orifice until expulsion or near expulsion of the system liquid from the dispensing orifice.

17. The method according to claim 16, wherein

said flowing the system liquid contained in the communication passageway is performed by actuating a dispensing valve from the closed condition to the opened condition.

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

before the aspirating a dispensing liquid, purging trapped gas contained in the dispensing valve.

19. The method according to claim 18, 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.

20. The method according to claim 19, wherein

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

21. The method according to claim 20, wherein

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

22. The method according to claim 21, 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.

23. The method according to claim 22, wherein

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

24. The method according to claim 21, wherein

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

25. The method according to claim 24, wherein

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

26. The method according to claim 2, 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.