PURPOSE: To apply a constant temp. upon fluid by changing the width of the heating pulses applied upon a heating means for heating the fluid according to the velocity of flow of the fluid.
CONSTITUTION: A heating element 13 and detecting elements 19 are provided in a flow pipe 11 in which fluid F flows. The heating pulses SH from a pulse width setting circuit 10 are applied to the element 13 through a heating circuit 18, and the time SD when the heated fluid passes through the elements 19 is detected with a heat sensing circuit part 15. The time difference ST between SD and SH is determined with a time setting circuit 16 and a flow rate is determined. Said circuit 10 is so constituted that it is driven by the ST when the ST is shorter than the time period of a timer 4 and is driven by the pulse SM of a pulse generator 5 of the narrower pulse width than that of the SH when it is longer than said period. Therefore, a generating body is preheated in such a way that it is set always at a constant temp. with respect to the measuring fluid.
NEMOTO TETSU
TSUBAKIMOTO HIROHISA
| JPS522761A | 1977-01-10 |