Fluid current meter

Abstract

Two pairs of acoustic transducers are provided for obtaining fluid current velocity measurements. The pairs of transducers are mounted in a supporting ring which introduces a controlled source of error in the measurement process, the configuration however resulting in a nearly constant error regardless of flow direction. The constant error introduced by the ring supporting structure may be easily corrected by a scaling factor in the signal processing circuitry utilized to compute fluid velocity.

I claim: .[.1. Fluid flow measuring apparatus comprising: 
     
        transducer..]. .[.2.  Apparatus according to claim 1 wherein: 
     
     
       A. said support means is a continuous circular ring..]. 3. Apparatus according to claim .[.2.]. .Iadd.5 .Iaddend.wherein: 
     
     
       A. said ring has a circular cross section. 4. Apparatus according to claim .[.2.]. .Iadd.5 .Iaddend.wherein: A. said ring has a hydrofoil shaped cross section defining a rounded   
     
     
        leading edge and a tapered trailing edge. 5. Fluid flow measuring apparatus comprising: A. a plurality of pairs of acoustic transducers;   B. a support ring .Iadd.having a plurality of recesses and .Iaddend.supporting said transducers .Iadd.within respective ones of said recesses.Iaddend.;   C. an electronics section coupled to and in signal communication with said transducers for obtaining current velocity measurements;   D. said transducers being supported by said ring such that the transducers of each said pair are acoustically coupled to one another along an acoustic path;   E. each said acoustic path being within the central portion of said ring.   
     
     
           Apparatus according to claim 5 wherein: A. two pairs of said transducers are provided and   B. said acoustic paths are mutually perpendicular. .[.7. Apparatus according to claim 5 wherein:   A. said support ring includes a plurality of notches;   B. each said transducer being positioned within a respective one of said   
     
     
        notches..]. 8. Apparatus according to claim .[.7.]. .Iadd.5 .Iaddend.wherein: A. said transducers are covered with a potting material having similar   
     
     
        acoustic transmission properties as the ambient water medium. 9. Apparatus according to claim 8 wherein: A. said potting material is shaped to conform with the cross sectional   
     
     
        shape of said support ring. 10. Apparatus according to claim .[.7.]. .Iadd.5 .Iaddend.wherein: A. said support ring includes a grooved portion, communicative with said .[.notches.]. .Iadd.recesses.Iaddend., for placement of signal conducting   
     
     
        wires. 11. Apparatus according to claim 5 which includes: A. a housing member;   B. said electronics section being contained within said housing member; and   
     
     
       C. strut means connecting said housing member with said support ring. 12. Apparatus according to claim 11 wherein: A. said strut means includes a plurality of support struts;   B. at least one of said support struts being hollow for receipt of signal conducting wires between said electronics section and said support ring.