Constant accuracy turbine meter

A turbine meter comprising a housing, a metering rotor having spaced blades and mounted for rotation in said housing in response to the flow of fluid through said meter, means for minimizing the tangential component in the direction of flow of fluid into said metering rotor, output means actuated by said metering rotor to provide an output representative of the fluid flow through said meter, sensing means downstream of said metering rotor for sensing the exit angle of the fluid leaving the blades of said rotor, control means actuated by said sensing means for modifying the output from said metering rotor in accordance with changes in said exit angle whereby said exit angle is maintained at a constant finite value, said control means including a brake associated with said metering rotor for varying the braking effort applied thereon.

A turbine meter comprising a metering rotor, output means actuated by said metering rotor to provide an output representative of fluid flow through said metering rotor, a sensing rotor downstream of said metering rotor for sensing the exit angle of the fluid leaving said metering rotor, braking means to vary the speed of rotation of said metering rotor, electric pulse producing means actuated by said sensing rotor for producing pulses commensurate with the amount of rotation of said sensing rotor, means responsive to the number of pulses from said pulse producing means for controlling said braking means to vary the braking effort applied by said braking means to said metering rotor in accordance with the number of pulses from said pulse producing means whereby said exit angle is maintained at a constant finite value.

A turbine meter comprising a housing, a metering rotor having spaced blades mounted for rotation in said housing in response to the flow of fluid through said meter, means to minimize the tangential component in the direction of fluid flow into said meter, a sensing rotor having spaced blades angularly oriented with respect to the axis of rotation of said rotor being rotatably mounted downstream from said metering rotor for sensing the exit angle of the fluid exiting from the blades of said metering rotor, the angle which the blades of said sensing rotor forms with the axis of rotation of said rotors being substantially less than the angle which the blades of said metering rotor forms with said axis, output means actuated by said metering rotor to provide an output representative of the fluid flow through said meter, control means controlled by said sensing rotor for modifying the output from said metering rotor in accordance with changes in said exit angle.