Pulse Flowmeter K-Factor (Frequency to Flow)

ScopeThe flow rate a pulse-output flowmeter (turbine, paddlewheel, or positive-displacement) reports from its output frequency: the meter emits a fixed K-factor of pulses per gallon (stamped on the meter or its calibration cert), so rate = frequency (Hz = pulses/sec) x 60 / K-factor, and the totalized volume is the pulse count / K-factor. A 200 pulse/gal meter reading 100 Hz is 30 gpm; a coarser 100 pulse/gal meter at the same 100 Hz is 60 gpm (each pulse is worth twice the volume). The K-factor drifts with fluid viscosity and shifts below the meter's linear range, so a viscous fluid or near-zero flow reads off; some meters are rated in pulses per liter or per cubic foot (convert first). Linear frequency-to-rate scaling; the calibration certificate, the linear flow range, and the fluid govern.

Formula or tableflow_gpm = frequency_hz x 60 / k_factor_pulses_per_gal; totalized volume (gal) = pulse_count / k_factor. flow_gph = flow_gpm x 60.

Source and editionPulse-output flowmeter (turbine / paddlewheel / positive-displacement) K-factor frequency-to-rate scaling, by name; the meter's calibration certificate and linear flow range govern.

Free accessThe frequency-to-rate relation is public first-principles (pulses per second over pulses per gallon); the K-factor is on the meter or its calibration certificate, and the frequency is the field reading.

What governsEstimate. AHJ and licensed professional govern.

API field namesfrequency_hz, k_factor_pulses_per_gal, flow_gpm, flow_gph

• K-factor scaling rate = frequency_Hz x 60 / K (pulses per gallon); totalized volume = pulse count / Kflowmeter practice
• K-factor not exactly constant drifts with viscosity and below the linear range; match pulses/gal vs /L vs /ft^3 units firstmeter calibration certificate