| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an inexpensive, compact, and high-performance flow rate sensor without having to enlarge its size even for high flow rates and provide a mass flow control apparatus using the same. <P>SOLUTION: The flow rate sensor 8 branches a fluid at a prescribed ratio of divergence, makes it flow through a bypass channel 12 and a sensor channel 14 wound with a heating resistance line, which forms part of a bridge circuit, and captures the shift of heat generated by the flow of the fluid through the sensor channel 14 as an unbalance of the bridge circuit to determine the overall flow rate of the fluid as sensor output. The bypass channel is constituted of a plurality of fine channels 74 comprising one approximately linear side and a curve in contact with the one side. A ratio between the equivalent hydraulic diameter (d) of the fine channels 74 and the common logarithm of the length (T) of the fine channels 74 is 0.27 or less. The flow rate sensor is built in the mass flow control apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
