Transducer housing for an ultrasonic fluid meter

1. A transducer housing comprising:

a housing having a proximal end, a distal end and an internal volume, the housing configured to couple to a spoolpiece of an ultrasonic meter;

an acoustic matching layer fluidly sealed directly to the distal end of the internal volume; and

an opening through the proximal end, the opening configured to enable selective insertion of a piezoelectric element to be proximate to the acoustic matching layer, and removal of the piezoelectric element, while the housing is coupled to the spoolpiece;

wherein the acoustic matching layer is configured to remain fluidly sealed to the distal end in the absence of the piezoelectric element from the internal volume with the acoustic matching layer exposed to a highest expected pressure of fluid within the ultrasonic meter;

wherein the acoustic matching layer has an acoustic impedance between that of the piezoelectric element and a fluid within the ultrasonic meter.

2. The transducer housing as defined in claim 1 wherein the housing further comprises threads on an outside diameter, and wherein the housing couples to the spoolpiece by way of the threads.

3. The transducer housing as defined in claim 1 wherein the acoustic matching layer has a thickness substantially equal to an odd multiple of one-quarter wavelength of sound generated by the piezoelectric element.

4. The transducer housing as defined in claim 1 wherein the acoustic matching layer has an acoustic impedance from about 1 to about 30 MRayl.

5. The transducer housing as defined in claim 1 wherein the acoustic matching layer is one or more selected from the group: glass; ceramic;

and plastic.

6. The transducer housing as defined in claim 1 wherein interior and exterior sides of the acoustic matching layer are substantially parallel.

7. The transducer housing as defined in claim 1 wherein exterior and interior sides of the acoustic matching layer are parallel to within at least 0.003 inches.

8. The transducer housing as defined in claim 1 wherein exterior and interior sides of the acoustic matching layer are substantially flat.

9. The transducer housing as defined in claim 1 wherein exterior and interior sides of the acoustic matching layer are flat to within at least 0.001 inch.

10. An ultrasonic meter comprising:

a spoolpiece having an internal flow path for a measured fluid; and

a transducer housing in operational relationship to the spoolpiece, the

transducer housing comprising:

an internal volume substantially at atmospheric pressure; and

an acoustic matching layer that seals the internal volume from the measured fluid, wherein the acoustic matching layer has an acoustic impedance between that of a piezoelectric crystal and the measured fluid, and wherein the acoustic matching layer is configured to remain between the internal volume and the measured fluid in the absence of the piezoelectric crystal and in the presence of a highest expected measured fluid pressure;

wherein the transducer housing is configured to receive the piezoelectric element to be proximate to the acoustic matching layer while the acoustic matching layer is exposed to the highest expected measured fluid pressure.

11. The ultrasonic meter as defined in claim 10 further comprising:

a transducer port in operational relationship to the spoolpiece;

wherein the transducer housing couples to the transducer port by a threaded coupling.

12. The ultrasonic meter as defined in claim 10 wherein the acoustic matching layer comprises one or more selected from the group: glass; ceramic; and plastic.

13. The ultrasonic meter as defined in claim 10 wherein exterior and interior sides of the acoustic matching layer are substantially parallel.

14. The ultrasonic meter as defined in claim 10 wherein exterior and interior sides of the acoustic matching layer are substantially flat.

15. The ultrasonic meter as defined in claim 10 further comprising a piezoelectric element abutting an interior side of the acoustic matching layer.

16. The ultrasonic meter as defined in claim 10 further comprising a biasing mechanism that biases the piezoelectric element towards the acoustic matching layer.

17. The transducer housing as defined in claim 1 wherein the housing is configured to accept a piezoelectric element within the internal volume to abut the acoustic matching layer.

18. The ultrasonic meter as defined in claim 10 wherein the transducer housing is configured such that the piezoelectric element is selectively inserted or removed from an abutting relationship to the acoustic matching layer.

19. The transducer housing as defined in claim 1 wherein the acoustic matching layer further comprises a meniscus circumscribing the acoustic matching layer on an internal volume side of the acoustic matching layer.

20. The ultrasonic meter as defined in claim 10 wherein the acoustic matching layer further comprises a meniscus circumscribing the acoustic matching layer on an internal volume side of the acoustic matching layer.