| 摘要 |
<p>PURPOSE:To keep the temperature difference between the ambient temperature and a sensor section constant and keep the outputs from thermally sensitive coils constant by adjusting the current flowing in the thermosensitive coils when the ambient temperature is changed. CONSTITUTION:A mass flow meter is provided with thermosensitive coils Ru, Rd changed with resistance values in response to the mass flow of a fluid in the upstream part and the downstream part of a conduit feeding the fluid, the upstream and downstream thermosensitive coils Ru, Rd are connected in series, and a resistor connected with an ambient temperature defecting resistor Rt having nearly the same characteristic as that of the thermosensitive coils Ru, Rd and a fixed resistor Rc having the temperature coefficient of nearly zero in series is connected to the thermosensitive coils Ru, Rd in series. A control circuit 1 controlling the voltage across both ends of the ambient temperature detecting resistor Rt and the fixed resistor Rc nearly equal to the voltage across both ends of the two upstream and downstream thermosensitive coils Ru, Rd is provided, and the mass flow of a fluid in a conduit is measured by the potential at the middle point of two thermosensitive coils Ru, Rd.</p> |
