A turbine flow meter is used for volumetric total flow and/or flow rate measurement and has a relatively simple working principle. As fluid flows through the turbine meter, it impinges upon turbine blades that are free to rotate about an axis along the center line of the turbine housing. The blades are built from a paramagnetic material. Pick-offs, mounted externally without contact with the fluid, create a magnetic field in the pipe. Thus, when the blades pass through this field, they generate voltage proportional to the velocity of rotation, which can be used to calculate the flow rate. The signal from the pick-offs can go into an external transmitter and convert to other types of communication. You can also use a pre-amplifier to read these pulses directly from the turbine flow meter without the transmitter.