Methods and apparatus for determining properties of a fluid

• US 7,353,695 B2
• Filed: 05/14/2007
• Issued: 04/08/2008
• Est. Priority Date: 06/08/2005
• Status: Expired due to Fees

• Current Assignee: ProterixBio, Inc.
• Original Assignee: BioScale, Inc.
• Inventors: Wenzel, Stuart, Fitch, Eric
• Primary Examiner(s): Williams; Hezron
• Assistant Examiner(s): FITZGERALD, JOHN P
• Application Number:
  US11/748,155
• Publication Number:
  US 20070204679A1
• Time in Patent Office: 330 Days
• Field of Search: 73/542.3, 73/542.4, 73/542.5
• US Class Current: 73/54.25
• CPC Class Codes: G01N 11/16 by measuring damping effect upon oscillatory body
• CPC Class Codes: G01N 9/002 using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence

Abstract

A method and system for determining properties of a fluid involves interacting the fluid with a standing wave in a first state to establish the standing wave in a second state, analyzing an electric signal associated with the standing wave to determine a characteristic associated with the second state, and determining the property of the fluid by comparing the characteristic with a function that associates a plurality of properties with a corresponding plurality of characteristics. The characteristic can include a maximum phase slope, a phase slope associated with a resonant frequency, a maximum magnitude associated with the resonant frequency, the value of the resonant frequency, or any combination thereof.

Claims

1. A method for determining a density of a fluid in a biosensing or chemical sensing application, the method comprising:

interacting the fluid with a standing wave having a first characteristic to establish a second characteristic;

measuring a frequency domain signal to determine a resonant frequency of the standing wave; and

determining density of the fluid by comparing the resonant frequency with a function that correlates a plurality of densities with a corresponding plurality of resonant frequencies.

2. A method for determining a property of a fluid, the method comprising:

providing an input signal to a resonant device to establish a standing wave in a surface of the resonant device, the standing wave having a first characteristic;

interacting the fluid with the standing wave to establish a second characteristic;

measuring an output signal of the resonant device in the frequency domain;

associating the output signal with the input signal or a reference signal to generate a second signal for selecting a signal value in the frequency domain, the signal value including a maximum phase slope, a phase slope at a resonant frequency, a maximum magnitude, or a magnitude at the resonant frequency of the second signal; and

determining the property of the fluid by comparing the signal value to a function that correlates a plurality of fluid properties with a corresponding plurality of signal values.

3. A method for determining a viscosity of a fluid in a biosensing or chemical sensing application, the method comprising:

interacting the fluid with a standing wave having a first characteristic to establish a second characteristic;

measuring a frequency domain signal associated with the first or second characteristic to determine a signal value based on a maximum phase slope, a phase slope at a resonant frequency of the signal, a maximum magnitude, or a magnitude at the resonant frequency of the signal; and

comparing the signal value to a function associating a plurality of viscosity values with a corresponding plurality of signal values to determine a viscosity value of the fluid.

4. The method of claim 3, further comprising controlling a temperature of the fluid with a thermoelectric cooler.

5. The method of claim 3, wherein the signal comprises a measured output compared to at least one of an input or a reference.

6. The method of claim 3, wherein the first characteristic is associated with a first time and the second characteristic is associated with a second time.

7. The method of claim 3, wherein the first characteristic is associated with the standing wave in the presence of a first fluid and the second characteristic is associated with the standing wave in the presence of a second fluid.

8. The method of claim 7, wherein the viscosity value is associated with the first fluid or the second fluid.

9. The method of claim 3, wherein the signal value comprises one or more phase values or phase slope values measured over a bandwidth of frequencies.

10. The method of claim 9, wherein the bandwidth of frequencies includes one or more resonant frequencies.

11. The method of claim 10, further comprising selecting the signal value from the phase slope at each of one or more resonant frequencies.

12. The method of claim 3, wherein the signal value comprises one or more maximum magnitude values measured over a bandwidth of frequencies.

13. The method of claim 12, wherein the bandwidth of frequencies includes one or more resonant frequencies.

14. The method of claim 13, further comprising selecting the signal value from the maximum magnitude value at each of the one or more resonant frequencies.