Portable gas detector and re-calibration method thereof

摘要

The present invention relates to a gas detector and, more particularly, to a gas detector that is provided with a gas sensor responding to a measurement object gas. The gas detector according to the present invention is capable of correcting a log value of a gas measured next based on a calibration value and a re-calibration reference value depending on the concentration of the gas (a minimum output value of the gas sensor and an output value of the gas sensor changing from moment to moment during recovery following gas injection). The gas detector according to the present invention, which is the gas detector that is provided with the gas sensor responding to the measurement object gas, includes: a button input portion for functional operations by a user; a gas injection unit for external gas transfer to the gas sensor; the calibration value made up of the output value of the gas sensor depending on the concentration of at least one standard gas transferred to the gas sensor; the re-calibration reference value made up of a reaction result value following the injection of a high-concentration gas such as a lighter gas and the sensor output value changing from moment to moment during the recovery following the high-concentration gas injection and used as a reference value for correction during re-calibration; a calculation unit converting a voltage value of the gas sensor depending on the concentration of the gas transferred to the gas sensor to a resistance value and the log value, executing calculation for finding out any concentration from an output value of a gas of any concentration with the calibration value, and executing a correction value generation calculation during the re-calibration; a memory unit storing the calibration value and the re-calibration reference value; a control unit executing the re-calibration by measuring the gas with the calibration value in the memory unit or generating and compensating for the measurement value correction value based on the re-calibration reference value; and a display unit displaying the measurement by the control unit and the state of the re-calibration.