Real-time volume confirmation dispensing apparatus and methods

Patent metadata

Field	Value
Publication number	US-9989551-B2
Application number	US-201414766729-A
Country	US
Kind code	B2
Filing date	Feb 14, 2014
Priority date	Feb 15, 2013
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A method of confirming volume during dispensing of a liquid using pressure. The method includes attempting to dispense a volume of the liquid from a dispense port, measuring a pressure associated with the attempted dispense of the liquid and providing a measured pressure signal, determining a liquid dispensing start time and a stop time based on a slope of the measured pressure signal, integrating the measured pressure signal between the start time and the stop time to provide an integrated pressure value, and comparing the integrated pressure value to one or more preset threshold values. Liquid dispensing apparatus are provided, as are other aspects.

First claim

What is claimed is:

1. A method of detecting pressure during dispensing of a liquid, comprising:
measuring the pressure of the liquid prior to dispensing the liquid from a dispense port to generate a reference pressure signal;
dispensing a volume of the liquid from the dispense port;
measuring the pressure of the liquid over a time period during the dispensing and providing a pressure signal in response to the measuring;
subtracting the reference pressure signal from the pressure signal to generate a measured pressure signal;
determining a start time when dispensing starts and a stop time when dispensing stops based on a slope of the measured pressure signal;
integrating the measured pressure signal between the start time and the stop time to provide an integrated pressure value; and
comparing the integrated pressure value to one or more preset threshold pressure values.

2. The method of claim 1 , comprising:
performing one or more experimental measurements of the pressure of the liquid during experimental dispensing, and
determining a predetermined nominal integrated pressure value based on the one or more experimental measurements,
wherein comparing the integrated pressure value to one or more preset threshold pressure values comprises comparing the integrated pressure value to one or more preset threshold pressure values having a setting of less than the predetermined nominal integrated pressure value.

3. The method of claim 1 , wherein comparing the integrated pressure value to one or more preset threshold pressure values comprises:
performing one or more experimental measurements of the pressure of the liquid during experimental dispensing,
determining a predetermined nominal integrated pressure value based on the one or more experimental measurements,
comparing the integrated pressure value to a lower threshold pressure value that is less than the predetermined nominal integrated pressure value, and
comparing the integrated pressure value to an upper threshold pressure value that is greater than the predetermined nominal integrated pressure value.

4. The method of claim 1 , wherein comparing the integrated pressure value to one or more preset threshold pressure values comprises:
performing one or more experimental measurements of the pressure of the liquid during experimental dispensing,
determining a predetermined nominal integrated pressure value based on the one or more experimental measurements, and
comparing the integrated pressure value to a threshold pressure value that is less than +/−5% from the predetermined nominal integrated pressure value.

5. The method of claim 1 , wherein comparing the integrated pressure value to one or more preset threshold pressure values comprises:
performing one or more experimental measurements of the pressure of the liquid during experimental dispensing,
determining a predetermined nominal integrated pressure value based on the one or more experimental measurements, and
comparing the integrated pressure value to a threshold pressure value that is less than +/−2% from the predetermined nominal integrated pressure value.

6. The method of claim 1 , further comprising detecting, in response to the comparing, one or more of:
an air bubble,
a system leak, and
a valve failure.

7. The method of claim 1 , further comprising detecting a presence of a blockage in response to the comparing.

8. The method of claim 1 , wherein the dispensing the volume of the liquid from the dispense port comprises dispensing one or more of:
an acid; or
a base.

9. The method of claim 1 , wherein the dispensing comprises dispensing the liquid into a reaction cuvette.

10. The method of claim 1 , wherein the pressure of the liquid is continuously measured during the dispensing.

11. The method of claim 1 , wherein if the integrated pressure value is outside the one or more preset threshold pressure values, then one of:
an alert is indicated; and
the dispensing is stopped.

12. The method of claim 1 , wherein the start time is determined by estimating a slope of the measured pressure signal, and wherein the start time occurs when the estimated slope exceeds a start threshold pressure value.

13. The method of claim 1 , wherein the stop time is determined by estimating a slope of the measured pressure signal, and wherein the stop time occurs when the estimated slope exceeds a stop threshold pressure value.

14. The method of claim 1 , comprising:
determining a first measured pressure signal of the liquid being dispensed at a beginning of a time window;
determining a second measured pressure signal of the liquid being dispensed at an end of the time window;
determining a difference between the first measured pressure signal and the second measured pressure signal; and
determining the start time of the dispensing as occurring when the difference between the first measured pressure signal and the second measured pressure signal exceeds a start threshold pressure signal value.

15. The method of claim 1 , comprising:
determining a first measured pressure signal of the liquid being dispensed at a beginning of a time window;
determining a second measured pressure signal of the liquid being dispensed at an end of the time window;
determining a difference between the first measured pressure signal and the second measured pressure signal; and
determining the stop time of the dispensing as occurring when the difference between the first measured pressure signal and the second measured pressure signal exceeds a stop threshold pressure signal value.

Assignees

• Siemens Healthcare Diagnostics Inc

Inventors

• Wang Litao
• Hsieh Pei-Ying

Classifications

• G01N35/1016 Primary

  Control of the volume dispensed or introduced · CPC title

• G01N2035/1018

  Detecting inhomogeneities, e.g. foam, bubbles, clots · CPC title

• G01L9/00

  Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements {(G01L11/004 takes precedence)}; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means (measuring differences of two or more pressure values G01L13/00; measuring two or more pressure values simultaneously G01L15/00) · CPC title