Temperature insensitive moisture sensor
US4928013A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 17, 1987 |
| Grant date | May 22, 1990 |
| Priority date | — |
| Expiry date | Feb 17, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/3166
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An infrared paper web moisture sensor is described which comprises a source of infrared radiation for directing an infrared beam through the web and an infrared detecting unit disposed on the opposite side of the web from the infrared source. In one embodiment, the infrared detecting unit measures the transmission of the infrared beam through the web at three separate wavelength regions of the infrared spectrum, one of which is sensitive to web temperature. In a second embodiment, the infrared detecting unit measures the transmission of the infrared beam through the web at two separate wavelength regions of the infrared spectrum, one of which is insensitive to web temperature. For each embodiment, signals are developed indicative of the transmission of infrared through the web in each of these regions, digitized, and fed to the process control computer for the paper mill. The computer combines the values of the digitized signals, via an empirically derived equation, to produce a value indicative of the percentage of moisture in the web. The process control computer utilizes this result of control devices which selectively add moisture to portions of the web or selectively dry porti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.