| 摘要 |
PURPOSE:To suppress the change in the temperature of hot water at a transient time to shorten a setting time by setting to zero by a timer an output from a feedback operational unit for a predetermined period of time from the abrupt change of a necessary quantity of heat. CONSTITUTION:When the quantity of supply water abruptly changes at a time t1, heat of combustion is throttled to a point (l) by a heat quantity operational circuit 10 after a delay (tau) of a water quantity detector 3. Upon this occasion, when a heat quantity change detecting circuit 14 differentiates an output signal of a circuit 10 and detects any change which is more than the predetermined change, the circuit 14 produces an output pulse (h), and a timer 15 produces an output (i) for a period of time tau1 after the output pulse (h) is inputted. Since the output from the feedback operational circuit 12 becomes zero while the output signal from the timer 15 is being produced, the quantity of combustion keeps the value of (l) determined only by the output from the circuit 10. The time tau1 of the timer is set slightly longer than the time obtained by totaling the time constant of a heat exchanger and a delay due to the length of a pipeline up to a feed hot water detector 5. From the time t2 onward, the output of a circuit 12 becomes effective and quantity of combustion is corrected by an integration element, and reaches a stability at a time t3. Thus, it is possible to shorten the setting time up to reaching the stability. |
