To provide a thermal type flowmeter capable of maintaining its measurement precision for a long period without pushing up the cost, by carrying out a countermeasure for fouling damages of a duct in which the flowmeter is installed in the case of being used in an exhaust gas atmosphere.
The duct inner cross section around the thermal type flowmeter in a passage duct is made large in comparison with its upstream side, thereby preventing any fouling damage nor degradation from occurring in the narrowest section around the thermal type flowmeter, and preventing the property from changing by the fouling damage of the passage duct. Since the fouling damage-resistant property of the flowmeter can be improved which mainly measures a flow rate of an exhaust gas, corresponding problems can be prevented from occurring, and the high-precision thermal type flowmeter whose life is long can be provided.
IGARASHI SHINYA
FUKATSU KATSUAKI
TOKUYASU NOBORU
IWAKI HIDEFUMI
SUKEGAWA YOSHIHIRO
YAMAOKA SHIRO
ICHIHARA TAKANOBU
| JPS6367933A | 1988-03-26 | |||
| JPS58178633A | 1983-10-19 | |||
| JP2004053429A | 2004-02-19 | |||
| JPS60236031A | 1985-11-22 | |||
| JPH041447A | 1992-01-06 |
Next Patent: THERMAL FLOWMETER AND SYSTEM