Constituent concentration indicator with a differentiator means and a signal conditioning means

Abstract

The Rolling Average Rate Read Indicator and Method detects the presence of a particular constituent in either a solid, liquid or gas and returns a rapid and accurate measurement of the concentration of the constituent. The Indicator is comprised of a sensor (12) containing a stepper motor (36) driven tape impregnated with a chemical substance reactive to a particular constituent. Discoloration of the tape occurs in the presence of the constituent and this discoloration is converted to an electrical signal which is indicative of the rate of change in the chemical reaction taking place and is linear for some portion of time. The signal is differentiated (16) and the resultant differentiated signal is indicative of the arithmetic mean of a plurality of instantaneous values taken at intervals during the linear portion of the reaction. The extent of the reaction as evidenced by the level of the sensor output signal is continuously monitored and compared (26) to a known value. If the sensor (12) output signal exceeds that of the known value the differentiated signal is transferred to a display device (22), the stepper motor (36) is activated and the sensor (12) tape is advanced in preparation for the receipt of a fresh sample. The tape advances only if a reaction has occurred. Optionally, the sensor (12) tape may be advanced at predetermined periodic intervals under the control of a timed override (30) or, at any time, by a manual override (34).

Dependencies are inferred from the claim text.