Mass rate of flow meter

In a mass rate of flow meter, having:

• a housing,
• first means for passing a fluid stream and having a first element rotating at the average angular velocity of the fluid stream,
• second means for receiving the fluid stream and for removing substantially all of the angular velocity therefrom, having a second element having a first angular orientation at a first angular momentum of the fluid stream, and for translating through an angular displacement from said first angular orientation and which displacement is a function of time rate of change of angular momentum of the fluid stream from said first angular momentum,
• the improvement of:
• a first source of magnetic flux fixed to said first element of said first means and rotating therewith,
• a first flux change detector fixed to said housing on a first radial orientation for detecting the passage of said first source through said radial orientation and for providing a first signal in response thereto,
• a second flux change detector fixed to said housing having an annular orientation to said second means for detecting a flux change and for providing a second signal in response thereto,
• a second source of flux having a third element fixed to said first element of said first means and rotating therewith and a fourth element fixed to said second element of said second means and displaced therewith, and providing a source of flux change when both said third and fourth elements are in conjunction, which change is detected by said second detector,
• an elapsed time meter which is turned on by said first signal and is turned off by said second signal, thereby to provide an indication of elapsed time which is a function of the time required for said first element to rotate through the displacement of said second element, which elapsed time is a function of the mass rate of flow of the stream.