MINUTE FLOWMETER AND SOLID-OXIDE FUEL CELL SYSTEM USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a minute flowmeter capable of achieving high precision measurement in a wide flow rate range.SOLUTION: A minute flowmeter comprises: a reducer 10 with a cross-sectional area getting smaller as fluid flows in a flow direction; a heater 21 which heats the fluid at an upstream side of a flow channel including the reducer 10; a temperature detection section 31 which detects temperatures of the fluid before and after heating at a downstream side of the heater 21; an information processing device 33 which obtains a flow rate from the temperatures detected by the temperature detection section 31; and a storage device which preliminarily stores a calibration function expressing a negative linear relation between an amount of increase in a fluid temperature and a flow rate. In the minute flowmeter, the information processing device 33 obtains: the amount of increase in the fluid temperature from the temperatures detected by the temperature detection section 31; and the flow rate, in a range from 0.2 mL/min or more to 10 mL/min or less, corresponding to the amount of increase in the fluid temperature. A distance L from the heater 21 to the temperature detection section 31 is in the range from longer than 0 mm to 3 mm or less and heating time of the heater 21 is in the range from 2 seconds or more to 4 seconds or less.