Ultrasonic transducer with low cavitation

• US 6,377,516 B1
• Filed: 12/08/2000
• Issued: 04/23/2002
• Est. Priority Date: 12/08/2000
• Status: Expired due to Term

• Current Assignee: Garmin Corporation (Garmin Limited)
• Original Assignee: Garmin Corporation (Garmin Limited)
• Inventors: Whiteside, John, Mehan, Craig
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US09/733,137
• Time in Patent Office: 501 Days
• Field of Search: 367/173, 367/165, 367/910, 367/188
• US Class Current: 367/173
• CPC Class Codes: G10K 11/006 Transducer mounting in underwater equipment, e.g. sonobuoys
• CPC Class Codes: Y10S 367/91 Portable sonar devices

Abstract

An ultrasonic sonar transducer (10) for attachment to a water vessel that more effectively transmits and receives sonar signals even when the water vessel is traveling at high speeds. The sonar transducer includes a transducer element (12) and a transducer housing (14) for housing the transducer element. The transducer housing includes a lower housing section (22) having a bottom wall (34) that is continuously curved with no major portion thereof parallel to the bottom face of the transducer element. The curved bottom is preferably bow-shaped so that the front of the transducer housing is raised relative to the rear to create a positive angle of attack relative to the oncoming water. This pressurizes water flow under the bottom of the transducer housing and promotes a laminar flow. Such a laminar flow reduces turbulence and cavitation and therefore nearly eliminates undesirable attenuation and reflection of transmitted and received energy. Although the transducer housing bottom is curved, the bottom face of the transducer element remains parallel to the surface of the water so that sonar is transmitted and received perpendicular to the surface of the water.

Claims

1. A sonar transducer for attachment to a water vessel, the sonar transducer comprising:

a transducer element operable for transmitting acoustic energy into and receiving acoustic energy from a body of water, the transducer element presenting a bottom face; and

a transducer housing for housing the transducer element, the transducer housing including a lower housing section having a bottom wall that is continuously curved with no major portion thereof parallel to the bottom face of the transducer element, wherein the bottom wall substantially continuously slopes down from a front end to a back end so that the front end is raised relative to the back end.

2. The sonar transducer as set forth in claim 1, the lower housing section also having side walls that curve into the bottom wall.

3. The sonar transducer as set forth in claim 1, wherein the bottom wall and the side walls of the lower housing section converge to form a substantially continuously arcuate front end that has no sharp transitions.

4. The sonar transducer as set forth in claim 1, the transducer housing further including an upper housing section that connects with the lower housing section.

5. The sonar transducer as set forth in claim 4, the transducer housing further including a mounting stem integrally formed with the upper housing section for attaching the sonar transducer to the water vessel.

6. The sonar transducer as set forth in claim 1, the bottom wall having a recessed portion that partially forms an acoustic window aligned with the bottom face of the transducer element for transmitting the acoustic energy from the transducer element out of the transducer housing and for receiving the acoustic energy back into the transducer housing.

22. The sonar transducer set forth in claim 1, wherein the bottom wall creates a slightly pressurized water flow under the bottom wall until oncoming water has reached the back end of the transducer housing.

7. A sonar transducer for attachment to a water vessel, the sonar transducer comprising:

a transducer element operable for transmitting acoustic energy into and receiving acoustic energy from a body of water, the transducer element presenting a bottom face; and

a transducer housing for housing the transducer element, the transducer housing including a lower housing section, the lower housing section including a bottom wall having a recessed portion that partially forms an acoustic window aligned with the bottom face of the transducer element for transmitting the acoustic energy from the transducer element out of the transducer housing and for receiving the acoustic energy back into the transducer housing, wherein the bottom wall substantially continuously slopes down from a front end to a back end so that the front end is raised relative to the back end.

8. The sonar transducer set forth in claim 7, the acoustic window further being formed by potting material positioned between the bottom face of the transducer element and the recessed portion of the bottom wall.

9. The sonar transducer set forth in claim 8, the recessed portion and the potting material being formed of material having a specific gravity approximately equal to a specific gravity of water.

10. The sonar transducer as set forth in claim 7, wherein the acoustic energy is of a selected wavelength, the acoustic window having a thickness approximately equal to one half of the wavelength or an integer multiple of one half of the wavelength.

11. The sonar transducer as set forth in claim 7, wherein the bottom wall is continuously curved with no major portion thereof parallel to the bottom face of the transducer element.

12. The sonar transducer as set forth in claim 7, the lower housing section also having side walls that curve into the bottom wall.

13. The sonar transducer as set forth in claim 7, wherein the bottom wall and the side walls of the lower housing section converge to form a substantially continuously arcuate front end that has no sharp transitions.

14. The sonar transducer as set forth in claim 7, the transducer housing further including an upper housing section that connects with the lower housing section.

15. The sonar transducer as set forth in claim 14, the transducer housing further including a mounting stem integrally formed with the upper housing section for attaching the sonar transducer to the water vessel.

23. The sonar transducer set forth in claim 7, wherein the bottom wall creates a slightly pressurized water flow under the bottom wall until oncoming water has reached the back end of the transducer housing.

16. A sonar transducer for attachment to a water vessel, the sonar transducer comprising:

a transducer element operable for transmitting acoustic energy into and receiving acoustic energy from a body of water, the transducer element presenting a bottom face; and

a transducer housing for housing the transducer element, the transducer housing including

a lower housing section having a bottom wall that is continuously curved with no major portion thereof parallel to the bottom face of the transducer element, the bottom wall having a recessed portion that partially forms an acoustic window aligned with the bottom face of the transducer element for transmitting the acoustic energy from the transducer element out of the transducer housing and for receiving the acoustic energy back into the transducer housing, wherein the acoustic energy is of a selected wavelength, the acoustic window having a thickness approximately equal to one half of the wavelength or an integer multiple of one half of the wavelength and the bottom wall substantially continuously slopes down from a front end to a back end so that the front end is raised relative to the back end to create a slightly pressurized water flow under the bottom wall until oncoming water has reached the back end of the transducer housing, and

an upper housing section that connects with the lower housing section.

17. A sonar transducer for attachment to a water vessel, the sonar transducer comprising:

a transducer element operable for transmitting acoustic energy into and receiving acoustic energy from a body of water, the transducer element presenting a bottom face; and

a transducer housing for housing the transducer element, the transducer housing including a lower housing section having a bottom wall, wherein the bottom wall substantially continuously slopes down from a front end to a back end so that the front end is raised relative to the back end to create a slightly pressurized water flow under the bottom wall until oncoming water has reached the back end of the transducer housing.

18. The sonar transducer as set forth in claim 17, the lower housing section also having side walls that curve into the bottom wall.

19. The sonar transducer as set forth in claim 17, the transducer housing further including an upper housing section that connects with the lower housing section.

20. The sonar transducer as set forth in claim 19, the transducer housing further including a mounting stem integrally formed with the upper housing section for attaching the sonar transducer to the water vessel.

21. The sonar transducer as set forth in claim 17, the bottom wall having a recessed portion that partially forms an acoustic window aligned with the bottom face of the transducer element for transmitting the acoustic energy from the transducer element out of the transducer housing and for receiving the acoustic energy back into the transducer housing.

24. A sonar transducer for attachment to a water vessel, the sonar transducer comprising:

a transducer element operable for transmitting acoustic energy of a selected wavelength into and receiving acoustic energy of the wavelength from a body of water, the transducer element presenting a bottom face; and

a transducer housing for housing the transducer element, the transducer housing including a lower housing section having a bottom wall with a recessed portion that partially forms an acoustic window having a thickness approximately equal to one half of the wavelength or an integer multiple of one half of the wavelength, wherein the bottom wall is continuously curved with no major portion thereof parallel to the bottom face of the transducer element and substantially continuously slopes down from a front end to a back end so that the front end is raised relative to the back end to create a slightly pressurized water flow under the bottom wall until oncoming water has reached the back end of the transducer housing.