BACKGROUND OF THE INVENTION
This invention relates generally to ultrasonic flow rate measurement, and more particularly to an ultrasonic coupler assembly.
Ultrasonic flow meters are used to determine the flow rate (i.e., mean pipe flow rate (¥„)) of a variety of fluids (e.g., liquids, gases, etc.) in the fluid flowing in pipes of different sizes and shapes. In one type of ultrasonic flow meter employing transit time flow metering, one or more pairs of ultrasonic transducers can be attached to the exterior of the pipe wall, where each pair can contain ultrasonic transducers located upstream and downstream from each other, forming an ultrasonic path between them. Each ultrasonic transducer, when energized, transmits an ultrasonic signal (e.g., a sound wave) along an ultrasonic path through the flowing fluid that is received by and detected by the other ultrasonic transducer. The path velocity (i.e., path or chord velocity (Vp)) of the flowing fluid averaged along an ultrasonic path can be determined as a ftinction of the differential between (i) the transit time of an ultrasonic signal traveling along the ultrasonic path from the downstream ultrasonic transducer upstream to the upstream ultrasonic transducer against the flow direction, and (2) the transit time of an ultrasonic signal traveling along the ultrasonic path from the upstream ultrasonic transducer downstream to the downstream ultrasonic transducer with the flow direction.
Knowledge of the flow rate of the fluid can enable other physical properties or qualities of the fluid to be determined. For example, in some custody-transfer applications, the flow rate can be used to determine the total volume (0 of a fluid (e.g., water, oil, or gas) being transferred from a seller to a bi^er through a pipe to determine the costs for the transaction, where the total volume is equal to the flow rate multiplied by the cross sectional area (A) of the pipe integrated over the time of flowing. In some applications (e.g., in refineries or nuclear power plants), the pipes to which the ultrasonic flow meters are attached are carrying high temperature fluids (e.g., coke in a refinery at 400°C) that cause the pipe walls to also reach extremely high temperatures, or are
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canying cryogenic fluids (

WE CLAIM:
1. An ultrasonic coupler assembly (300, 400) for coupling an ultrasonic
transducer (310,410) to a pipe wall (320,420) comprising:
a first quadrilateral section (340,440);
a second quadrilateral section (360,460); and
a rhomboid section (350,450) between and connecting the first quadrilateral section (340, 440) and the second quadrilateral section (360,460).
2. The ultrasonic coupler assembly (300, 400) of claim 1, wherein the rhomboid section (350,450) comprises a top side (352,452) extending from the right end of the top side (342,442) of the first quadrilateral section (340, 440) to the left end of the top side (362,462) of the second quadrilateral section (360,460), a bottom side (354, 454) extending from the right end of the bottom side (344,444) of the first quadrilateral section (340, 440) to the left end of the bottom side (364,464) of the second quadrilateral section (360,460), a left side (356,456) adjacent to the right side (346,446) of the first quadrilateral section (340, 440), and a right side (358, 458) adjacent to the left side (366, 466) of the second quadrilateral section (360,460), wherein the top side (352, 452) is parallel to the bottom side (354, 454), the left side (356,456) is parallel to the right side (358,458), the left side (356,456) forms an acute angle with the top side (352,452) and an obtuse angle with the bottom side (354,454), and the right side (358,458) forms an obtuse angle with the top side (352,452) and an acute angle with the bottom side (354, 454).
3. The ultrasonic coupler assembly (300) of claim 1, wherein the first quadrilateral section (340) is a trapezoid.
4. The ultrasonic coupler assembly (300) of claim 3, wherein the first quadrilateral section (340) comprises a top side (342) extending from the right end of the
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top side (352) of the rhomboid section (350), a bottom side (344) extending from the left end of the bottom side (354) of the rhomboid section (350), a right side (346) adjacent to the left side (356) of the rhomboid section (350), and a left side (348), wherein the top side (342) is parallel to the bottom side (344), the right side (346) forms right angles with the top side (342) and the bottom side (344), and the left side (348) forms an acute angle with the top side (342) and an obtuse angle with the bottom side (344).
5. The ultrasonic coupler assembly (300) of claim 1, wherein the second quadrilateral section (360) is a trapezoid.
6. The ultrasonic coupler assembly (300) of claim 5, wherein the second quadrilateral section (360) comprises a top side (362) extending from the right end of the top side (352) of the rhomboid section (350), a bottom side (364) extending from the right end of the bottom side (354) of the riiomboid section (350), a left side (366) adjacent to the right side (358) of the rhomboid section (350), and a right side (368), wherein the top side (362) is parallel to the bottom side (364), the left side (366) forms right angles with the top side (362) and the bottom side (364), and the right side (368) forms an obtuse angle with the top side (362) and an acute angle with the bottom side (364).
7. The ultrasonic coupler assembly (400) of claim 1, wherein the first quadrilateral section (440) is an orthogonal parallelogram.
8. The ultrasonic coupler assembly (400) of claim 7, wherein the first quadrilateral section (440) comprises atop side (442) extending from the left end of the top side (452) of the rhomboid section (450), a bottom side (444) extending from the left end of the bottom side (454) of the rhomboid section (450), a right side (446) adjacent to the left side (456) of the rhomboid section (450), and a left side (448), wherein the top side (442) is parallel to the bottom side (444), the right side (446) is parallel to the left side (448), the right side (446) forms right angles with the top side (442) and the bottom
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side (444), and the left side (448) forms right angles with the top side (442) and the bottom side (448).
9. The ultrasonic coupler assembly (400) of claim 1, wherein the second
quadrilateral section (460) is an orthogonal parallelogram.
10. The ultrasonic coupler assembly (400) of claim 9, wherein the second quadrilateral section (460) comprises a top side (462) extending from the right end of the top side (452) of the rhomboid section (450), a bottom side (464) extending from the right end of the bottom side (454)of the rhomboid section (450), a left side (466) adjacent to the right side (458) of the rhomboid section (450), and a right side (468), wherein the top side (462) is parallel to the bottom side (464), the right side (468) is parallel to the left side (466), the left side (466) forms right angles with the top side (462) and the bottom side (464), and the right side (468) forms right angles with the top side (462) and the bottom side (464).
11. The ultrasonic coupler assembly (300,400) of claim 1, further comprising a wedge (312,412) proximate the top side (342,442) of the first quadrilateral section (340, 440).
12. The ultrasonic coupler assembly (300, 400) of claim 1, further comprising a wedge (312,412) proximate the bottom side (364, 464) of the second quadrilateral section (360,460).
13. The ultrasonic coupler assembly (300) of claim 6, wherein the acute angle between the right side (368) of the second quadrilateral section (360) and the bottom side (364) of the second quadrilateral section (360) is configured such that the portion of a main ultrasonic signal that is reflected at an interface point (363) between the bottom side (364) of the second quadrilateral section (360) and the pipe wall (320) is reflected along a reflected ultrasonic path (305) that is normal to the right side (368) of the second quadrilateral section (360).
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14. The ultrasonic coupler assembly (300,400) of claim 1, wherein the
first quadrilateral section (340,440), the second quadrilateral section (360,460), and the rhomboid section (350,450) together form a single piece.