| 摘要 |
<p>PROBLEM TO BE SOLVED: To make it possible to measure the flow rate of air highly accurately even under the pulsation flow state by measuring the counterflow time by utilizing the rising and trailing of an output waveform, and correcting the error from the time. SOLUTION: When heating resistors 1a and 1b are arranged in a main air path and a secondary air path 4, respectively, the resistors sensitively react with a downflow 2. For a counterflow 3, the sensitive reaction occurs in the main air path. Since the counterflow does not enter into the secondary air path 4, there is no detection for the counterflow. Therefore, each output waveform indicates the approximately same waveform at the time of downflow and indicates the different waveform at the time of counterflow. Especially the rising and tailing of the waveform are equal at the time of downflow. On the contrary, the rising and trailing indicate the opposite directions at the time of counterflow. Therefore, when the rising and trailing are always monitored, the flow direction signal can be taken out. When the rising an trailing are detected are found to be equal, it is judged that there is no counterflow, and the correcting value is made to be zero. When they are different, it is judged that there is the counterflow, and the time of counterflow is measured. The correcting value for the counterflow component is operated by the time, and the correction is performed.</p> |
