| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a flowmeter which is capable of measuring a flow rate with high precision and sensitivity, all over the wide flow rate ranging from a flow rate region of a very small amount to a comparatively large flow rate region. <P>SOLUTION: On the basis of an output Vh of an indirectly heated constant temperature control type flow rate measuring part 16 and an output Vout of two constant point temperature difference detecting type flow rate measuring parts 18a, 18b, a measured value is obtained by an operation part. In the flow rate measuring part 16, a heating element 163 is subjected to feedback control based on a detected temperature of a temperature sensing element 162, and the output Vh is obtained on the basis of a state of the feedback control. The flow rate measuring parts 18a, 18b obtain the output Vout on the basis of detected temperature difference between a temperature sensing element 182 arranged in the upstream side of the measuring part 16 with respect to a fluid flow direction and a temperature sensing element arranged in the downstream side. The operation part outputs a flow rate value as a measured value, which is obtained on the basis of the output Vh in a flow rate range of at least previously determined boundary flow rate, and outputs a flow rate value, as a measured value, which is obtained on the basis of the output Vout, in a flow rate region less than the boundary flow rate. <P>COPYRIGHT: (C)2004,JPO</p> |
