Sensor for measuring changes in ambient conditions

• US 20030184309A1
• Filed: 03/29/2002
• Published: 10/02/2003
• Est. Priority Date: 03/29/2002
• Status: Abandoned Application

• Current Assignee: Jerome R. Lurtz
• Original Assignee: Jerome R. Lurtz
• Inventors: Lurtz, Jerome R.
• Application Number:
  US10/113,301
• Publication Number:
  US 20030184309A1
• Time in Patent Office: Days
• US Class Current: 324/525
• CPC Class Codes: G01K 7/223 characterised by the shape of the resistive element
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: G01L 9/0002 using variations in ohmic resistance G01L9/0051 takes precedence

Abstract

The present invention relates to a sensor, which includes a conductor connected to a source terminal, while a second conductor is connected to a return terminal. Between the two conductors resides a semi-conductive layer with a predetermined resistance. A resistance measurement device determines how the predetermined resistance of the semi-conductive layer changes in response to a change in pressure or temperature. Also, included is a sensor with integral fault detection. The present invention also relates more generally to a coaxial cable, which includes a semi-conductive layer between two conductors. The present invention also incorporates a method of sensing pressure or temperature by measuring a change in resistance of a semi-conductive layer.

Claims

1. A sensor comprising:

a first conductor connected to a first source terminal;

a second conductor connected to a first return terminal;

a semi-conductive layer with a predetermined resistance located between said first and second conductors; and

a resistance measurement device,

wherein said predetermined resistance changes in response to a change in pressure or temperature.

2. The sensor of claim 1, wherein said first and second conductors are coaxial.

3. The sensor of claim 1, wherein said semi-conductive layer includes a thermoplastic.

4. The sensor of claim 1, wherein said semi-conductive layer includes a conductive material.

5. The sensor of claim 4, wherein said conductive material is carbon.

6. The sensor of claim 1, further including a protective jacket.

7. The sensor of claim 1, further including a substrate.

8. The sensor of claim 1, wherein fault detection is integral.

9. The sensor of claim 1, further including a separate fault detection device.

10. The sensor of claim 9, wherein said separate fault detection device includes said first conductor connected to a second return terminal and said second conductor connected to a second source terminal.

11. The sensor of claim 10, further comprising a timing device.

12. The sensor of claim 1, wherein said first and second conductors are copper;

said semi-conductive layer is low density polyethylene doped with lampblack; and

said protective jacket is low density polyethylene.

13. A device comprising:

a first conductor;

a second conductor; and

a semi-conductive layer located between said first and second conductors;

wherein said first and second conductors are coaxial.

14. The device of claim 13, wherein said semi-conductive layer includes a thermoplastic.

15. The device of claim 14, wherein said semi-conductive layer includes a conductive material.

16. The device of claim 14, wherein said conductive material is carbon.

17. The device of claim 13, further including a protective jacket.

18. The sensor of claim 13, further including a substrate.

19. A method of sensing changes in ambient conditions, comprising:

passing electricity through a semi-conductive layer with a predetermined resistance;

measuring a change in the predetermined resistance in response to a change in pressure or temperature.

20. The method of claim 19, wherein said semi-conductive layer separates a first conductor that is coaxial with a second conductor.

21. The method of claim 20, wherein said semi-conductive layer includes a thermoplastic.

22. The method of claim 21, wherein said semi-conductive layer includes a conductive material.

23. The method of claim 22, wherein said conductive material is carbon.