Electrical circuit for turbine flowmeter - compensates for inaccuracies due to turbine inertia particularly during interrupted flows

摘要

Measurements of flow using turbine flow meters in which the flow is measured by the number of turns of the turbine are inaccurate when flow is interrupted, due to inertia of the turbine. An electrical circuit senses and compensates for this inaccuracy. The output (E) of a detector coil associated with a turbine is amplified (5) and the positive and negative half cycles of the signal are separated by a diode rectifiers (8, 9). The positive signals are applied to an integrator (10) while the negative signals are passed to a voltage comparator (11). A controlled switch (12) is connected between the integrator output and the second input (C2) of the comparator. The negative signals are applied to a monostable (14) controlling the switch (12) and also to a second monostable (15) which resets the integrator to zero. A monostable (18) at the comparator output provides counting signals (5).