Systems and methods of a transducer having a plastic matching layer

1. A transducer 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;

a circumferential ridge on the outside of the distal end of the housing;

a plastic matching layer that has an external surface and an internal surface, the plastic matching layer seals to and occludes the distal end of the housing, and the plastic matching layer couples over the circumferential ridge; and

a transducer element abutting the internal surface of the plastic matching layer.

2. A transducer 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;

a circumferential groove on the outside of the distal end of the housing;

a plastic matching layer that has an external surface and an internal surface, the plastic matching layer seals to and occludes the distal end of the housing, and the plastic matching layer couples over the circumferential groove; and

a transducer element abutting the internal surface of the plastic matching layer.

3. A transducer 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;

a taper on the distal end of the housing;

a plastic matching layer that has an external surface and an internal surface, the plastic matching layer seals to and occludes the distal end of the housing, and the plastic matching layer couples over the taper; and

a transducer element abutting the internal surface of the plastic matching layer.

4. The transducer as defined in claim 1 wherein the transducer element is configured to provide structural support for the plastic matching layer.

5. The transducer as defined in claim 1 wherein the plastic matching layer has an acoustical impedance between that of the transducer element and of a measured medium.

6. The transducer as defined in claim 1 wherein the plastic matching layer has a coefficient of thermal expansion greater than that of the housing.

7. The transducer as defined in claim 1 further comprising:

an electrical pin disposed on the proximal end of the housing;

wherein the electrical pin is coupled to the transducer element; and

wherein the electrical pin is sealed to the housing.

8. An ultrasonic meter comprising:

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

a transducer in operational relationship to the spoolpiece, the transducer comprising:

a housing that defines an internal volume;

a plastic matching layer that separates the internal volume of the housing from the measured fluid;

a piezoelectric element abutting an internal surface of the plastic matching layer; and

a biasing mechanism that biases the piezoelectric element towards the plastic matching layer;

wherein the plastic matching layer has an acoustic impedance between that of the piezoelectric element and the measured fluid.

9. The ultrasonic meter as defined in claim 8 wherein the internal volume is substantially at atmospheric pressure.

10. The ultrasonic meter as defined in claim 8 wherein the transducer element is configured to substantially prevent inward deflection of the plastic matching layer.

11. The transducer as defined in claim 2 wherein the plastic matching layer has a coefficient of thermal expansion greater than that of the housing.

12. The transducer as defined in claim 2 wherein the transducer element is configured to provide structural support for the plastic matching layer.

13. The transducer as defined in claim 2 wherein the plastic matching layer has an acoustical impedance between that of the transducer element and of a measured medium.

14. The ultrasonic meter as defined in claim 8 further comprising:

a transducer port through the spoolpiece;

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

15. The transducer as defined in claim 2 further comprising:

an electrical pin disposed on the proximal end of the housing;

wherein the electrical pin is coupled to the transducer element; and

wherein the electrical pin is sealed to the housing.

16. The transducer as defined in claim 3 wherein the transducer element is configured to provide structural support for the plastic matching layer.

17. The transducer as defined in claim 3 wherein the plastic matching layer has an acoustical impedance between that of the transducer element and of a measured medium.

18. The transducer as defined in claim 3 wherein the plastic matching layer has a coefficient of thermal expansion greater than that of the housing.

19. The transducer as defined in claim 3 further comprising:

an electrical pin disposed on the proximal end of the housing;

wherein the electrical pin is coupled to the transducer element; and

wherein the electrical pin is sealed to the housing.

20. The transducer as defined in claim 1 wherein the circumferential ridge encompasses the distal end.

21. The transducer as defined in claim 2 wherein the circumferential groove encompasses the distal end.