Moisture sensor for layers

• US 20010002105A1
• Filed: 01/05/2001
• Published: 05/31/2001
• Est. Priority Date: 07/24/1998
• Status: Active Grant

• Current Assignee: Forschungszentrum Karlsruhe Gmbh
• Original Assignee: Forschungszentrum Karlsruhe Gmbh
• Inventors: Brandelik, Alexander, Hubner, Christof
• Granted Patent: US 6,507,200 B2
• Time in Patent Office: Days
• US Class Current: 324/696
• CPC Class Codes: G01N 22/04 Investigating moisture content

Abstract

In a moisture sensor for monitoring the moisture content of layers, at least two parallel electrical conductors connected to a measuring apparatus are disposed adjacent the layers to be monitored. The conductors are surrounded by an insulating material and carry, at their side remote from the layer whose dielectric coefficient is to be monitored, a metal shielding layer for limiting the measurement field of the sensor.

Claims

1. A moisture sensor for layers, said moisture sensor including a conductor arrangement with two parallel electrical conductors connected to a measuring apparatus for determining dielectric coefficients, a cable including two spaced conductors disposed between said two parallel conductors and connected with said two parallel conductors in a three-conductor circuit, the space between the conductors of said cable being selected for the adjustment of the impedance of said conductor arrangement, said electrical conductors being surrounded by an insulating material layer and carrying at one side, which is remote from the layer whose dielectric coefficient is to be measured, a metal shielding layer for limiting the measurement field of the moisture sensor.

2. A moisture sensor according to

claim 1

, wherein said conductors with said insulating layer and said metal shielding are flexible.

3. A moisture sensor according to

claim 1

, wherein said conductors have a measuring field and they are arranged at a distance from each other, which is so selected, that the measuring depth of the measuring field is comparable to the thickness of the layer whose moisture content is to be determined.

4. A moisture sensor according to

claim 1

, wherein said conductors with the insulating layer and the metal shielding have a wave resistance which during measurement is adapted to the characteristic resistance of the measuring apparatus.

5. A moisture sensor according to

claim 1

, wherein a water permeable metal layer is disposed on top of the layer whose dielectric coefficient is to be monitored.

6. A moisture sensor according to

claim 1

, wherein said layer to be monitored consists of a porous water-retaining material.

7. A moisture sensor according to

claim 1

, wherein said moisture sensor is disposed adjacent a betonite layer for determining the water content thereof.

8. A moisture sensor according to

claim 6

, wherein said moisture sensor is disposed adjacent the ground for determining ice formation on the ground and on objects close to the ground.