Univeral calibration system and method for a high performance, low volume, non-contact liquid dispensing apparatus

• US 20030167822A1
• 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 6,983,636 B2
• Time in Patent Office: Days
• US Class Current: 73/1.16
• 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

A universal calibration apparatus and method to estimate the dispense output from a low volume, non-contact, liquid dispensing systems that may be applied for every hardware configuration (e.g., tube length, orifice diameter, tip design, etc), reagent solution property and environmental condition. This same calibration technique is applied to calibrate or tune these non-contact liquid dispensing systems to dispense desired volumes (in the range of about 0.050 μL to 50 μL), irrespective of the hardware configuration or the solution properties. That is, the calibration technique is not dependent on any variables, but the result (the actual dispense volume) is dependant on the variable mentioned. By actuating selected pulse widths, and measuring the resulting volume, a Calibration Profile can be generated correlating the liquid volume dispensed from the orifice to the respective pulse width of the dispensing valve thereof through calibration points.. In particular, one is selected to deliver a first volume of liquid that is less than a lower base pulse width correlating to the lowest volume of the selected range of volumes of liquid, while a second pulse width is selected to deliver a second volume of liquid dispensed that is greater than an upper ceiling pulse width correlating to the highest volume of the selected range of volumes of liquid. Intermediary pulse widths are also applied, each selected to deliver a different, spaced-apart, respective intermediary low volumes of liquid dispensed from the dispensing orifice between the first volume and the second volume. Thus, applying the Calibration Profile, the pulse widths correlating to the one or more targeted discrete volumes for liquid dispensing can be extrapolated.

Claims

1. A method for calibrating a non-contact, liquid dispensing apparatus to enable substantially precise, low volume, liquid dispensing of one or more targeted discrete volumes of a selected dispensing liquid within a selected range of volumes of liquid, the dispensing apparatus providing a communication passageway having a proximal end fluidly coupled to a fluid reservoir maintained at a substantially constant positive pressure for ejection of the dispensing liquid out of an opposite end dispensing orifice of the communication passageway, the dispensing apparatus further including a precision actuation dispensing valve in fluid communication with the communication passageway downstream from the fluid reservoir and adapted for rapid actuation between a closed condition, preventing flow of the pressurized fluid through the actuation valve from the fluid reservoir to the dispensing orifice, and an opened condition, enabling flow of the pressurized fluid through the dispensing valve from the fluid reservoir to the dispensing orifice, the method comprising:

(a) precisely actuating the dispensing valve from the closed condition to the opened condition and back to the closed condition for a first pulse width selected to deliver a first volume of liquid dispensed from the dispensing orifice that is less than a lower base pulse width correlating to the lowest volume of the selected range of volumes of liquid;

accurately determining the first volume of liquid dispensed;

(b) precisely actuating the dispensing valve from the closed condition to the opened condition and back to the closed condition for a second pulse width selected to deliver a second volume of liquid dispensed from the dispensing orifice that is greater than an upper base pulse width correlating to the highest volume of the selected range of volumes of liquid;

accurately determining the second volume of liquid dispensed;

(c) precisely actuating the dispensing valve from the closed condition to the opened condition and back to the closed condition for at least three different, spaced-apart, intermediary pulse widths, each selected to deliver a different, spaced-apart, respective intermediary low volumes of liquid dispensed from the dispensing orifice between the first volume and the second volume;

accurately determining each respective intermediary volume of liquid dispensed;

(d) forming a Calibration Profile correlating the liquid volume dispensed from the orifice to the respective pulse width of the dispensing valve thereof through calibration points determined from the first volume, the second volume, and the at least three intermediary volumes, and the corresponding lower base pulse width, upper base pulse width and the intermediary pulse widths, and extrapolating the Calibration Profile substantially through the calibration points.

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

determining one or more target pulse widths from the Calibration Profile correlating to the one or more targeted discrete volumes of liquid for application on the dispensing valve to substantially accurately dispense the one or more targeted discrete volumes of liquid from the dispensing orifice.

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

estimating an inflection point along the Calibration Profile where transient flow through the dispensing valve occurs in a transient flow region on one side of the inflection point, and static flow occurs in a static flow region on the other side of the inflection point;

in the transient flow region, precisely actuating the dispensing valve from the closed condition to the opened condition and back to the closed condition for at least two different, spaced-apart, transient pulse widths, each selected to deliver a different, spaced-apart, respective transient volumes of liquid dispensed from the dispensing orifice.

accurately determining each respective transient volume of liquid dispensed; and

further forming the Calibration Profile through the transient calibration points determined from the respective transient volumes, and the corresponding transient pulse widths, and further extrapolating the Calibration Profile substantially through the transient calibration points.

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

in the static flow region, precisely actuating the dispensing valve from the closed condition to the opened condition and back to the closed condition for at least one static pulse width to deliver a respective static volume of liquid dispensed between the inflection pulse width and the upper base pulse width;

accurately determining the static volume of liquid dispensed; and

further forming the Calibration Profile through an at least one static calibration point determined from the at least one static volumes, and the corresponding static pulse widths, and further extrapolating the Calibration Profile substantially through the at least one static calibration point.

5. A method for assessing the liquid flow performance for dispensing liquid through a relatively small diameter dispensing orifice fluidly coupled to a communication passageway of a precision, low volume, liquid handling system, the method comprising:

emitting an optical beam, from a position outboard from one side of the dispensing orifice, along an optical path extending substantially laterally across and downstream from the dispensing orifice of the liquid handling system prior to dispensing liquid from the dispensing orifice;

continuously sensing the optical beam along the optical path, from a position outboard from an opposite side of the dispensing orifice;

flowing the dispensing liquid through the communication passageway generally sufficient to eject at least a drop of dispensing liquid from the dispensing orifice, and across the optical path of the optical beam, wherein;

detecting the drop indicates a flow condition of the dispensing fluid through the dispensing orifice; and

wherein

not detecting the drop indicates a non-flow condition of the dispensing fluid through the dispensing orifice.

6. The method according to claim 5, wherein

the emitting of an optical beam includes activating a laser diode emitting the optical beam.

7. The method according to claim 6, wherein

the continuously sensing the optical beam includes detecting the optical beam through a receiving component of a sensor assembly configured to detect the optical beam emitted from the diode

8. The method according to claim 7, wherein

the detecting the drop includes adjusting the sensitivity of the receiving component so that the drop of dispensed liquid from the dispensing orifice is more “

visible”

to the receiving component.

9. The method according to claim 8, wherein

the adjusting the sensitivity intensity of the receiving component of the sensor assembly includes decreasing the intensity of the optical beam received by the receiving component.

10. The method according to claim 9, wherein

the decreasing the intensity of the received optical beam is performed by positioning a diffuser in the optical path of the optical beam between the dispensing orifice and the receiving component of the sensor assembly.

11. The method according to claim 5, wherein

the detecting the drop includes identifying a change in the continuous sensing of the optical beam, and

not detecting the drop includes not identifying a change in the continuous sensing of the optical beam.

12. The method according to claim 11, wherein

the identifying a change includes detecting the pause in the continuous sensing of the optical beam, and

the not identifying a change includes not detecting a pause in the continuous sensing of the optical beam.

13. A method for assessing the operational flow condition for dispensing liquids through a plurality of relatively small diameter dispensing orifices aligned in a substantially linear array and each fluidly coupled to a respective communication passageway of a precision, low volume, liquid handling system, the method comprising:

(a) emitting an optical beam, from a position outboard from one side of the linear array of the dispensing orifices, along an optical path extending substantially along a longitudinal axis of the linear array, and substantially laterally across and downstream from each dispensing orifice of the liquid handling system prior to dispensing liquid from any one of the dispensing orifice;

(b) continuously sensing the optical beam along the optical path, from a position outboard from an opposite side of the linear array of the dispensing orifices;

(c) flowing the dispensing liquid through a respective communication passageway generally sufficient to eject at least a drop of dispensing liquid from one of the dispensing orifices, and across the optical path of the optical beam, wherein;

(d) detecting the drop indicates a flow condition of the dispensing fluid through the one dispensing orifice; and

wherein

(e) not detecting the drop indicates a non-flow condition of the dispensing fluid through the one dispensing orifice; and

(f) sequentially repeating events (c)-(e) for the remaining dispensing orifices to assess the operational flow condition for the entire array of dispensing orifices.

14. The method according to claim 13, wherein

the emitting of an optical beam includes activating a laser diode emitting the optical beam.

15. The method according to claim 14, wherein

the continuously sensing the optical beam includes detecting the optical beam through a receiving component of a sensor assembly configured to detect the optical beam emitted from the diode

16. The method according to claim 13, wherein

the detecting the drop includes adjusting the sensitivity of a receiving component of a sensor assembly so that the respective drop of dispensed liquid from the respective dispensing orifice is more “

visible”

to the receiving component.

17. The method according to claim 16, wherein

the adjusting the sensitivity intensity of the receiving component of the sensor assembly includes decreasing the intensity of the optical beam received by the receiving component.

18. The method according to claim 17, wherein

the decreasing the intensity of the received optical beam is performed by positioning a diffuser in the optical path of the optical beam between the dispensing orifice and the receiving component of the sensor assembly.

19. The method according to claim 13, wherein

the detecting the drop includes identifying a change in the continuous sensing of the optical beam, and

not detecting the drop includes not identifying a change in the continuous sensing of the optical beam.

20. The method according to claim 19, wherein

the identifying a change includes detecting the pause in the continuous sensing of the optical beam, and

the not identifying a change includes not detecting a pause in the continuous sensing of the optical beam.