Instrumentation for sensing moisture content of material using a transient thermal pulse
Abstract
Instrumentation is developed for sensing moisture content of material using a transient thermal pulse and is comprised of a sensing probe having a sensing element in the form of a ribbon excited by a constant current pulse to increase the temperature, and therefore the resistance, of the ribbon linearly. Moisture in web material limits 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 Wheatsone 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:
- November 1981
- Bibcode:
- 1981nasa.rept.....Y
- Keywords:
-
- Drying;
- Moisture Content;
- Moisture Meters;
- Pulse Heating;
- Transient Heating;
- Webs (Sheets);
- Electric Current;
- Energy Conservation;
- Feedback Control;
- Patent Applications;
- Resistance Heating;
- Wheatstone Bridges;
- Instrumentation and Photography