PURPOSE: To obtain a flowmeter which can accurately output pulses at every unit flow rate without sacrificing the detecting accuracy and measuring range by providing a sensor which converts the flow rate of a fluid into pulse signals, control means, and pulse width generating means.
CONSTITUTION: A sensor means 3 converts the flow rate of a fluid into pulse signals at a prefixed rate (pulse rate). When the pulse signals are inputted, a control means 4 detects and counts the pulse signals, converts the pulse signals into the flow rate by multiplying the pulse signals by the pulse rate, and finds the cumulative flow rate of the fluid by adding the converted flow rate from time to time. The variation of the cumulative flow rate is monitored and whether or not the variation exceeds a fixed amount is detected B. When the variation exceeds the fixed amount, a pulse outputting means C outputs a pulse TR for driving a pulse width generating means 5. The means 5 outputs a pulse PLS having a pulse width broader than a pulse width decided by the count value of a counter 6. Since the pulse width generating means 5 generates a pulse width in accordance with the driving pulse outputted from the control means 4, the processing work of the control means 4 is reduced and the flow rate of the fluid can be accurately measured even when the flow rate is large.
NAKANE SHINICHI
ATSUMI TORU
