| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a thermal flow meter capable of high accuracy measurement, by reducing the temperature measurement errors of a temperature detection means or the influence of noise, even when the flow rate becomes high. <P>SOLUTION: This thermal flowmeter for controlling the temperature of liquid flowing in a passage and measuring the flow rate, based on the temperature difference of fluid between the upstream side and the downstream side of a temperature control part, is provided with a passage, wherein all liquid contact parts are constituted of glass; a heat transfer means provided in the passage; temperature detection means on the upstream side and on the downstream side provided on the passage, at positions that are at equal intervals from the heat transfer means; and an operation control means for controlling so that the temperature of the heat transfer means is raised successively, as the flow rate of the liquid flowing in the passage becomes high, determining the temperature difference specified, by dividing the temperature difference between each temperature detected by the temperature detection means on the upstream side and on the downstream side by the temperature sum, and determining the flow rate, based on the specified temperature difference. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
