RF-4 is a very inexpensive and practical solution for measurement of flow rate and amount in liquid fluids mostly free of particles.
The working principle is based on the principle that the moving liquid will rotate the propeller, which is axis perpendicular to the direction of movement, at its own speed.

The electronic measuring cell that detects the motion of the sensor is completely enclosed by the outer body and is isolated from the liquid and the environment.

Since there is no mechanical connection between the fluid contact zone and the electronic cell and the external environment, the body is completely closed, sealed and pressure resistant.