| 摘要 |
PROBLEM TO BE SOLVED: To provide a thermal flowmeter which can measure, with high accuracy, a flow rate of gas flowing in forward and reverse directions.SOLUTION: A thermal flowmeter includes: a sub passage 4234 for taking in and passing measurement gas 30 that flows in a main passage; and a flow rate measurement circuit which measures a flow rate by transferring heat to and from the measurement gas that flows in the sub passage. The sub passage has an outlet 352 being open toward a downstream side of a flow direction of the measurement gas. Further, upstream from the outlet 352 is provided an outlet chamber 4216. In the outlet chamber 4216 is provided a guide 4217 for changing the flow direction of the measurement gas that enters from an opposite side relative to the outlet so as to face the outlet. An inflow portion of the outlet chamber and the outlet are off-axis from the flow direction of the measurement gas flowing in the main passage. |
