DID YOU KNOW?

Turbine meters turn blade pulses into flow rate using frequency (Hz) and K-factor.

"Did You Know?"
Turbine meters turn blade pulses into flow rate using frequency (Hz) and K-factor.

Understanding how turbine meters convert fluid movement into accurate flow measurements is key to getting reliable performance from your metering system. At the heart of this process are two fundamental concepts: frequency and K-factor. These two values work together to translate the mechanical rotation of a turbine into meaningful flow data you can use for monitoring, batching, or process control.

This Did You Know breaks down the basics of turbine meter frequency and K-factor—what they are, how they relate to one another, and why they matter. You’ll also learn how real-world factors like fluid viscosity and internal friction can affect accuracy, and how tools like FLOMEC’s Q9 display and calibration reports help ensure your measurements stay precise. Whether you're new to turbine technology or need a clear refresher, this guide provides the essential foundation you need.

1. Frequency

• As the turbine rotates, the turbine blades pass through the magnetic field created by a magnetic pickup.
• Each blade passing through the magnetic field generates a pulse.
• The frequency of these pulses is measured in hertz (Hz). Frequency is the number of pulses per second, and is directly proportional to the flow rate:
  
  Higher flow→faster turbine rotation→higher pulse frequency.  

2. K-Factor

• The K-factor is a calibration constant provided by the meter manufacturer.
• It represents the number of pulses generated per unit volume of fluid (e.g., pulses per gallon or pulses per liter).
• Formula:
  
  K-factor = Number of pulses / volume of fluid
  

How They Work Together
To calculate the actual flow:

Flow Rate = Frequency X Seconds / K-factor
In this case we are looking for a flow rate in gallons per minute (gpm). There are 60 seconds in a minute, so use 60 for the seconds.

For Example: 

• If the frequency is 500 Hz and the K-factor is 100 pulses per gallon (ppg), then:
  
  Flow Rate = 500 Hz x 60 sec. / 100 ppg = 300 gpm
  

Accuracy Tips

Did you know that friction inside the turbine can slightly change the K-Factor at different flow rates? That’s why Flomec Calibration Reports include multiple K-Factors at different flow rates. Even better—the Q9 display (G2, A1, & TM Series) automatically selects the correct K-Factor for the current flow rate, ensuring top-notch accuracy.

Flomec Calibration Reports use water for the calibration fluid. If your liquid is thicker than water the turbine will spin slower creating a lower frequency and a smaller K-factor. The Q9 display can also be field calibrated. Simply determine the percentage of your inaccuracy, enter it into the Q9 display, and it will adjust all the existing calibration points by that percentage. This means the Q9 display will continue to select the correct K-Factor for the current flow rate, giving you the best accuracy possible.

Note: Turbine meters can be used on liquids up to 30–50 cPs with recalibration and reduced accuracy.