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US 6,047,602 AGranted
Ultrasonic buffer/waveguide
AssigneePanametrics, Inc.
InventorLawrence C. Lynnworth
Life of this patent
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AssigneePanametrics, Inc.
InventorLawrence C. Lynnworth
Estimating the term…
A waveguide couples ultrasonic energy from a source on one side of a fluid-bounding wall, such as a conduit, into fluid on the other side of the wall. The waveguide has a buffer that couples to the source, and a seat with an exit face, while an intermediate portion contains a redirecting surface for internally redirecting energy propagated along the buffer toward the exit face to exit as a narrow directed beam. The waveguide core has a rectangular cross section which is narrow, i.e., has an aspect ratio above two and preferably above three or four, while the buffer has a length effective to thermally isolate or protect the source from the conduit. The waveguide attaches easily, either as a clamp-on or welded unit, to a pipe or spoolpiece, allowing local fabrication of massive or custom flow cells, such as large spoolpieces with Gauss-Chebyshev interrogation paths. Several guides may be positioned in an array to cover interrogation paths for an extended range of sound speeds or flow rates. In one embodiment the redirecting face may be curved, or stepped at different angles, to provide output beams at several or a continuum of exit angles. A low sound speed material may be added to control the refraction angle of the exit beam in the wall or fluid. The construction readily adapts to wetted systems. The waveguide may have the overall shape of a hockey stick, with the buffer and the seat lying in a common plane, or one may curve into, or join at an angle, the other. Features such as holes, notches or the like may provide reference echoes for a flow meter to automatically calculate temperature-dependent transit time corrections for the buffer, and additional reflective surfaces or topological features such as holes may redirect echoes or noise out of the measurement path. In one embodiment, the buffer is a thin tube which couples shear waves into the seat portion, which has a rectangular cross section.
A waveguide for interposition between an ultrasonic wave source and a fluid-bounding wall to couple ultrasonic energy from the source on one side of the wall into fluid on the other side of the wall to effect a measurement thereof, said waveguide having a guided path centerline with a length dimension along a direction of signal propagation within said waveguide, and having a thickness dimension and a transverse dimension, the length dimension being substantially greater than the thickness dimension, the ratio of the transverse dimension to the thickness dimension defining an aspect ratio, and said waveguide comprising a standoff portion, a middle portion and a seat
A waveguide comprising a standoff portion connected to a seat portion formed of a plate, wherein the standoff portion has a first end for coupling to a transducer and a second end extending to the seat, and has a length between said first and second ends effective to substantially dissipate high temperature applied at the seat when the seat is coupled to a hot conduit, wherein the seat has a cross section effective to propagate shear wave energy non-dispersively and without mode conversion to an exit face and radiate said energy as a narrow and directional beam into the conduit, and said standoff portion is configured to couple energy which has been applied at said first end to the seat portion as shear wave energy which travels in a defined direction through the seat portion to said exit face thereby controlling an angle of refraction at the exit face.
A kit for the field fabrication of a spoolpiece or flow conduit for ultrasonic measurement of fluid flow in a desired plane, such kit consisting of a waveguide having a standoff portion and a seat portion connected to the standoff portion, the seat portion being formed of a plate, wherein the standoff portion has a first end for coupling to a transducer and a second end extending to the seat, and has a length between said first and second ends effective to substantially dissipate high temperature applied at the seat when the seat is attached to a hot conduit, wherein the seat has a cross section effective to propagate shear wave energy non-dispersively and without mode conversion to an exit face and radiate said energy as a narrow and directional beam, and said standoff portion is configured to couple energy which has been applied at said first end to the seat portion as shear wave energy which travels in a defined direction through the seat portion to said exit face thereby controlling an angle of refraction at the exit face, so that field fabrication is achieved simply by securing the exit face to the spoolpiece or conduit in an orientation to position the beam in said plane.
Dependencies are inferred from the claim text.