Flexible Fluid Level Sensor With Improved Measurement Capability

• US 20140152323A1
• Filed: 12/05/2012
• Published: 06/05/2014
• Est. Priority Date: 12/05/2012
• Status: Active Grant

• Current Assignee: Molex LLC (KOCH Industries Incorporated)
• Original Assignee: Molex Incorporated (KOCH Industries Incorporated)
• Inventors: Kumar, Arun, Fulton, Steven John
• Granted Patent: US 9,488,513 B2
• Time in Patent Office: Days
• US Class Current: 324/658
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3389 Continuous level detection A61M2205/3393 takes precedence
• CPC Class Codes: A61M 5/1684 by detecting the amount of infusate remaining, e.g. signalling end of infusion
• CPC Class Codes: G01F 23/00 Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm

Abstract

A capacitive fluid sensor is provided that utilizes a flexible substrate. It has a plurality of conductive members supported on it which are connected to a connecting end. The conductive members are arranged in an array and are aligned with a longitudinal axis of the substrate and the members are separated by intervening spaces. The intervening spaces are arranged so that they cross the longitudinal axis at an angle such that adjacent conductive members overlap each other when viewed from a side edge of the sensor. Such an arrangement provide more accurate measurement of fluid levels within containers.

Claims

1. A capacitive fluid level sensor for sensing a level of a fluid within a vessel, the sensor positioned alongside the vessel and separated from the fluid by a wall of the vessel, the sensor comprising:

a flexible substrate capable of conforming to the wall of the vessel;

a plurality of conductive, planar members supported by the substrate, the conductive members being spaced apart from each other by intervening spaces and aligned in an array arranged along a longitudinal axis of the substrate, the intervening spaces between adjacent ones of the conductive members being disposed such that they intersect the longitudinal axis at an angle; and

a plurality of conductive traces extending between individual conductive members and a connecting end of the substrate.

2. The capacitive fluid level sensor of claim 1, wherein the connecting end includes a plurality of contact pads for connecting to terminals of a receptacle connector.

3. The capacitive fluid level sensor of claim 1, wherein the conductive traces are arranged in two distinct groups flanking the conductive member array.

4. The capacitive fluid level sensor of claim 3, wherein the two distinct groups of conductive traces include an even-numbered group of conductive traces and an odd-numbered group of conductive traces.

5. The capacitive fluid level sensor of claim 1, further including an adhesive layer disposed along a surface of the substrate.

6. The capacitive fluid level sensor of claim 1, wherein each of the conductive members includes at least four distinct sides.

7. The capacitive fluid level sensor of claim 6, wherein all but two of the conductive members are parallelograms.

8. The capacitive fluid level sensor of claim 6, wherein all but two of the conductive members are configured as chevrons.

9. The capacitive fluid level sensor of claim 1, wherein the conductive members are arranged in the array such that, in any of the conductive members included between end members of the conductive member array, an imaginary line drawn normal to the substrate longitudinal axis will intersect contacts two adjacent conductive members.

10. The capacitive fluid level sensor of claim 1, wherein the intervening spaces extend in two distinct directions.

11. The capacitive fluid level sensor of claim 1, wherein, with the exception of the conductive members at opposite ends of the array, the conductive members are identical to each other.

12. The capacitive fluid level sensor of claim 1, wherein the substrate is a strip of polyester.

13. The capacitive fluid level sensor of claim 1, wherein the conductive members are formed from conductive material deposited onto a surface of the substrate.

14. The capacitive fluid level sensor of claim 1, further including a ground grid extending around the perimeter of the conductive member array.

15. The capacitive fluid level sensor of claim 14, wherein the ground grid includes a plurality of conductive traces arranged in an intersecting pattern, defining a plurality of openings in the ground grid, each such opening being enclosed by a plurality of conductive traces.

16. A capacitive fluid level sensor for sensing a level of a fluid within a vessel, the sensor positioned alongside the vessel ad separated from the fluid by a wall of the vessel, the sensor comprising:

a flexible substrate capable of conforming to the wall of the vessel;

an elongated conductive planar member supported by the substrate, the conductive members being aligned along a longitudinal axis of the substrate and a conductive ground grid surrounding the conductive member, the ground grid including a plurality of conductive traces arranged in a interconnected pattern, the traces defining a plurality of associated openings, each such opening being entirely enclosed by the traces; and

a plurality of conductive traces extending between the conductive member and the ground grid and a connecting end of the substrate.