Understanding Flow Rate Calculation using K-Factor
In industrial instrumentation and fluid dynamics, the K-Factor is a critical calibration value assigned to turbine flow meters and other pulse-generating flow measurement devices. It represents the number of electrical pulses the meter generates for every unit of fluid volume (such as a gallon or liter) that passes through it.
To convert the raw frequency output (Hz) from a flow meter into a readable volumetric flow rate (like Gallons Per Minute or Liters Per Hour), you must apply the K-Factor formula. This calculator automates that conversion process.
The K-Factor Formula
The basic mathematical relationship between frequency, flow rate, and K-Factor is:
Q = (f × T) / K
Where:
Q = Volumetric Flow Rate (e.g., GPM, LPM)
f = Output Frequency in Hertz (pulses per second)
K = K-Factor (pulses per unit volume)
T = Time base multiplier (60 for minutes, 3600 for hours)
How to Use This Calculator
Enter Frequency: Input the frequency value displayed on your frequency counter or PLC input, measured in Hertz (Hz).
Enter K-Factor: Input the K-Factor provided on the flow meter's calibration certificate or tag. This is typically in "Pulses per Gallon" or "Pulses per Liter".
Select Time Base: Choose whether you want the result in units per second, minute, or hour. For example, if your K-Factor is in Pulses/Gallon and you select "Minute", your result will be in Gallons Per Minute (GPM).
Common Applications
This calculation is standard for turbine flow meters, positive displacement gears, and Coriolis meters with pulse outputs. It is essential for configuring batch controllers, PLC high-speed counters, and digital panel meters in industries ranging from water treatment to petrochemical processing.
Example Calculation
Suppose you have a turbine meter with a K-Factor of 120 pulses/gallon. The meter is outputting a frequency of 500 Hz. To find the flow rate in Gallons Per Minute (GPM):
Frequency (f) = 500 pulses/sec
Time Multiplier (T) = 60 (to convert seconds to minutes)