Gas detecting and monitoring device
Patent 4498330 Issued on February 12, 1985. Estimated Expiration Date: 
May 10, 2002. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
May 10, 2002. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2759354 3429178 3634757 Thermochemical combustible gas detector Method and apparatus for preventing the destruction of an alkali source of a nitrogen-phosphorous detector Patent #: 4202666 InventorAssigneeApplicationNo. 06/376519 filed on 05/10/1982US Classes:73/23.21, With compensation detail (for error or drift correction, etc.)73/25.03ThermoconductivityExaminersPrimary: Kreitman, Stephen A.Attorney, Agent or FirmInternational ClassG01N 27/12 (20060101)Foreign Application Priority Data1981-05-15 JPAbstractA gas detecting and monitoring device comprises a bridge circuit including a gas detecting element and a constant-current circuit for feeding a constant current to the gas detecting element. The device further comprises a compensating bridge circuit including at least a part of the gas detecting element. The compensating bridge circuit produces a signal corresponding to the variation of the resistance value of the gas detecting element depending upon the variation of the ambient temperature and feeds the signal to the constant-current circuit to automatically control the current fed to the bridge circuit thereby maintaining the resistance value of the gas detecting element at a constant value. The device may further comprise a correcting circuit including a temperature sensor for sensing the variation of the ambient temperature disposed near the gas detecting element. The correcting circuit feeds the output of the temperature sensor corresponding to the variation of the ambient temperature to the compensating bridge circuit thereby compensating for the variation of the respective circuit components owing to the variation of the ambient temperature. | |
