| 摘要 |
<p>PURPOSE:To obtain a mass flow meter whose response speed is high, and which is scarcely influenced by an ambient temperature by providing independently a constant temperature difference circuit containing a heat sensitive coil whose resistance value is varied in accordance with a temperature of a fluid, on the upstream and downstream sides of a conduit through which the fluid flows, respectively. CONSTITUTION:When a fluid G is flowing through the inside of a conductor 1, as for an induction coil Ru of the upstream side (or an induction coil Rd of the downstream side), heat is taken off by the fluid G, the fluid is heated and the temperature rises (or heat is received from the heated fluid). Therefore, in order to hold a temperature difference between an ambient temperature and the coil Ru (or Rd), energy larger (or smaller) than a state that the fluid G is not flowing is required. By detecting a difference of the energy supplied to the coils Ru, Rd, generated in such a case, a mass flow rate is measured. In such a way, in the coils Ru, Rd, temperature difference setting resistances Rtu, Rtd having a small temperature coefficient, inserted in series into ambient temperature detecting resistances Rtu, Rtd which have a characteristic being equal to that of said coils, have improved the heat conduction and can execute enough the radiation exist. Accordingly, a difference between the ambient temperature and a temperature of the coil is always kept constant irrespective of a variation of the ambient temperature.</p> |
