Instrumentation for sensing moisture content of material using a transient thermal pulse
Abstract
Instrumentation for sensing moisture content of material using a transient thermal pulse is comprised of a sensing probe having a sensing element in the form of a ribbon excited by a constant current pulse from a source to increase the temperature and therefore the resistance of the ribbon linearly. Moisture in web material will limit the increase of temperature during the pulse in proportion to the moisture content. This increase in temperature produces a proportional increase in resistivity which is measured with a wheatstone bridge as a change in voltage displayed by a measurement display unit. The probe is glued in a shallow groove of a Lucite bar and connected to copper pins embedded in the bar.
- Publication:
-
National Aeronautics and Space Administration Report
- Pub Date:
- August 1985
- Bibcode:
- 1985nasa.reptR....Y
- Keywords:
-
- Detection;
- Dew Point;
- Display Devices;
- Electrical Resistivity;
- Infrared Instruments;
- Linearity;
- Measuring Instruments;
- Microwave Equipment;
- Moisture Content;
- Moisture Meters;
- Pulsed Radiation;
- Resistance Heating;
- Thermal Radiation;
- Transient Heating;
- Webs (Sheets);
- Wheatstone Bridges;
- Copper;
- Dew Point;
- Hygroscopicity;
- Oscilloscopes;
- Patents;
- Polymethyl Methacrylate;
- Instrumentation and Photography