Spectrophotometer
US3935463A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 5, 1974 |
| Grant date | Jan 27, 1976 |
| Priority date | — |
| Expiry date | Dec 5, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/152
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved spectrophotometer of the non-dispersive absorption type useful for detecting the presence of SO.sub.2 in a gaseous sample, despite the simultaneous presence of NO.sub.2. Ultraviolet light from a commercially-available source impinges upon a fixed phosphor screen which fluoresces to produce ultraviolet radiation at a first wavelength, at which both SO.sub.2 and NO.sub.2 absorb radiation; and at a second wavelength at which absorption by SO.sub.2 is minimal but NO.sub.2 absorption is approximately the same as at the first wavelength. The radiation is directed through a sample chamber having windows which are transversely slidable to effect cleaning without destroying the integrity of the chamber seal, then introduced into an envelope enclosing filters and a pair of photosensors. One photosensor receives light at the second wavelength and produces a signal which reflects the attenuation by NO.sub.2 at that wavelength. The other sensor has disposed in front thereof a filter for blocking the second wavelength, and passing the first; and a phosphor for converting the passed (first) wavelength radiation into radiation at the second wavelength, which is then detected to produce…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.