Abstract: A turbine meter used for measuring the volume of fluid flowing through a conduit includes an elongated housing having an upstream end and a downstream end and a rotor mounted within the housing. A plurality of turbine blades are mounted on the rotor at an angle with respect to the axis of rotation of the rotor which causes each of the rotor blades to have a high pressure surface which faces toward the upstream end of the housing. Each of the rotor blades also has a trailing edge closest to the downstream end of the housing. An extension is included at approximately the trailing edge on the high pressure surface of at least one and preferably a plurality of the rotor blades. The extension has a length and forms an angle with respect to the high pressure surface of the rotor blade on which it is mounted which causes the percentage of error of the accuracy of the meter across a chosen operating range of the meter to be within predetermined limits.

Abstract: A gas turbine meter includes a measuring cartridge which has a measuring rotor that rotates in one direction at a speed approximately proportional to the velocity of gas flowing through the meter and a reference rotor mounted downstream of the measuring rotor which rotates in the opposite direction from the measuring rotor. An inlet flow straightener upstream of the measuring rotor causes gas to flow substantially axially within the meter, and a reference flow straightener mounted between the measuring rotor and the reference rotor also causes gas to flow substantially axially within the meter. The inlet flow straightener and the reference flow straightener are constructed so that a measurement of the accuracy of the meter can be conducted without measuring differences in pressure and temperature between the locations of the measuring rotor and the reference rotor.