What Is a Flowmeter? How does a Flowmeter work?
The flowmeter counts the volume of water that is passing through the group. It can be found in auto-volumetric configuration espresso machines.
It consists of a body, an impeller, and a sensor head. The body contains a ‘jet’ which is a small orifice through which water is directed on to the impeller. The impeller turns as water flows. The head has three ‘Hall effect’ sensors inside, which react to the presence of a magnet. The impeller has two magnets that pass close to these sensors as it turns. The control board supplies a small voltage to the flowmeter and as the magnets pass the sensors, the flow meter returns this voltage as a series of pulses. The control board counts the pulses and consequently knows the volume of water which has passed through the flowmeter.