Turbine flow meters

Small magnets on the rotor hub are electronically detected by a solid-state hall-effect sensor outside the wetted area. The turbine rotor uses journal -type sapphire and ruby bearings for minimum friction and maximum life. These bearings are suitable for long life in water and water-based fluids and are said to have exceptional low-flow characteristics. http://www.omega.co.uk/pptst/FTB700-S.html