Static equilibrium path for measurements of dynamic flows

• US 10,338,025 B2
• Filed: 08/02/2018
• Issued: 07/02/2019
• Est. Priority Date: 09/22/2011
• Status: Active Grant

• Current Assignee: Sentient Technologies, Inc.
• Original Assignee: Sentient Technologies, Inc.
• Inventors: Johnson, Frederick Quincy
• Primary Examiner(s): Kessel, Maris R
• Application Number:
  US16/053,528
• Publication Number:
  US 20180340908A1
• Time in Patent Office: 334 Days
• CPC Class Codes: G01N 27/414 Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS
• CPC Class Codes: G01N 27/4148 Integrated circuits therefor, e.g. fabricated by CMOS processing CMOS processing per se H01L21/82

Abstract

A meter is adapted for measuring concentrations of a chemical in a flowing solution. The meter has a barrier that shields a sensor from the high turbulence of the solution flow. One or more membranes can be employed to selectively filter out various ions or other chemicals.

Claims

1. An ion meter for measuring a solution with dynamic flow, comprising:

a substrate having an interior side with an ISFET gate, and an exterior side, a reference electrode;

a circuit board bonded to at least a portion of the substrate; and

a barrier comprising the interior side of the substrate, the ISFET gate, and a portion of the circuit board;

wherein the barrier partially defines a cavity providing a static equilibrium environment for the solution; and

wherein the barrier further partially defines a fluid pathway to the exterior side of the substrate.

2. The ion meter of claim 1, wherein the substrate comprises silicon.

3. The ion meter of claim 1, wherein a liquid turbulence in the cavity is lower than a liquid turbulence on the exterior of the substrate.

4. The ion meter of claim 1, wherein the liquid turbulence in the cavity has a liquid turbulence of at most 25% the liquid turbulence at the exterior of the substrate.

5. The ion meter of claim 1, further comprising a filtering membrane spanning the fluid pathway to separate the cavity from the exterior side of the substrate.

6. The ion meter of claim 5, wherein the filtering membrane selectively prevents at least one solute from entering the cavity.

7. The ion meter of claim 1, wherein the fluid pathway to the exterior side of the substrate comprises at least one switchback bend.

8. The ion meter of claim 1, further comprising a frit layer in direct communication with the cavity, wherein the frit layer fluidly separates the reference electrode from the cavity.

9. The ion meter of claim 8, wherein the frit layer fluidly seals the reference electrode in a chamber containing ionizing solution.