Infrared gas analyzer with automatic zero adjustment
US4687934A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1986 |
| Grant date | Aug 18, 1987 |
| Priority date | — |
| Expiry date | Jan 10, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/12769
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Automatic zeroing apparatus zeroes an infrared gas analyzer automatically upon the occurrence of preselected conditions to indicate zero in the absence of absorption of infrared radiation by a gas mixture being analyzed. The gas analyzer has a sample cell for containing a gas mixture to be analyzed. Infrared radiation directed through the sample cell is detected at a preselected wavelength to produce a detection signal. A signal processor outputs a signal systematically related to the difference between the detection signal and a reference signal. For zeroing the sample cell is filled with gas substantially nonabsorbent of infrared radiation at the respective characteristic wavelength. A comparator produces an error signal when the output signal differs from zero. A gain control automatically controls the signal level of the detection signal to reduce the output signal substantially to zero with the nonabsorbent gas filling the sample cell. The preselected conditions may include the passage of a predetermined time and a temperature drift beyond a predetermined limit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.