We have three choices of flowmeter when it comes to dirty flows like irrigation and waste water -- Doppler, Magnetic, and Propeller Flowmeters.


Doppler ultrasonic flowmeters measure liquid flow from the outside of full pipes. A typical system incorporates a transmitter w/totalizer and a transducer. The transducer is mounted to the exterior of the pipe. An ultrasonic signal, generated by the transmitter, is emitted through the transducers into the flowing liquid and is then reflected back by the discontinuities. The transmitter measures the difference between the output and input frequency and converts the frequency difference into electronic pulses. These pulses are scaled and totaled for flow quantity.


Magnetic flow meters are close to being the ideal flow meter for liquids, i.e. all solid state, no moving parts, accuracy's down to 0.2% of rate, capable of handling most corrosive fluids. The measuring tube is an open pipe, you could run tree branches through the meter without hurting it. If the fluid is a conductor, there is very little this meter cannot handle.


Propeller meters are bulk water meters, designed specifically to handle dirty fluids. Originally these meters were designed for the irrigation market, where the water can be silt laden, have plant material, small rocks, etc. There are only three propeller blades and they have a very long body with the front edges angled backwards. This allows vegetation to hit the rotor and slide off of it without catching. Propeller meters are a cost effective solution to a very dirty problem.

All three types have their advantages. Take a look at the brands we offer by clicking on a manufacturer below: