| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To attain a thermal gas flow rate measuring device, capable of suppressing influence on an output characteristics caused by dirt of a support body of a heat-generating resistor, regardless of the utilization environment. <P>SOLUTION: A first heat-generating resistor 21 is arranged in gas to be measured, and a signal related to the flow rate is output from a thermometric resistor 24, arranged on the upstream or downstream of the first heat-generating resistor 21. A second heat-generating resistor 22, electrically insulated from the first heat-generating resistor 21, is arranged between the first heat-generating resistor 21 and the support body 2 for supporting it. The heat quantity, transmitted from the first heat-generating resistor 21 to the support body 2, is suppressed by the second heat-generating resistor 22. The temperatures of the first heat-generating resistor 21 and the second heat-generating resistor 22 are controlled by a control circuit 31 so that the practical utilization temperature range of the second heat-generating resistor 22 or the temperature range of the connecting part between the first heat-generating resistor 21 and the second heat-generating resistor 22 is not lower than the temperature, at which water drops evaporates and disappear due to film boiling. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
