Heat responsive flowmeter for air in pipe

摘要

The air flowmeter involves a low pass filter incorporating a capacitor and a choke coil arranged between a filament resistance (7) and a heat sensitive resistance (8), and a temp. control circuit. The temp. control circuit controls the filament resistance, which is used to measure the air flow. An intermediate junction point is provided, at which a connection of the capacitor is connected with a connection of the choke coil, which is connected with at least one of the two resistances, and the other connection of the choke coil is connected to the temp. control circuit. The other connection of the capacitor is earthed, separately from the signal circuit earth.