| 摘要 |
<p>PURPOSE:To reduce the heat conduction between a hot wire and a support and to improve wall temperature characteristics based upon the temperature difference between the main body of a flow meter and sucked air by connecting one end of the center conductor of the hot wire to the support in a cantilever state. CONSTITUTION:The hot wire consists of the center conductor 1, an insulating layer 2, a resistance wire 3, a glass coating 4, the hot wire 5, and the support 6. Then, the hot wire 5 is connected to the support 6 in the cantilever state and installed in a bypass passage 9, and a current is so supplied from a flow meter 7 through the support 6 as to heat the hot wire 5 to constant temperature. This heating temperature is held constant regardless of the flow rate of the sucked air 11. Namely, when the sucked air 11 flows in the bypass passage 9 at a high flow rate, a large current is supplied to the hot wire 5 and when the flow rate is low, a small current is supplied to the hot wire 5, thereby holding the temperature of the hot wire 5 constant. At this time, there is a relation expressed by a monotonous increase function between the current flowing through the hot wire 5 and the flow rate of the sucked air 11, and the flow rate of the sucked air 11 is detected from this function relation.</p> |
