High power ultrasonic transducer

• US 6,137,209 A
• Filed: 07/07/1999
• Issued: 10/24/2000
• Est. Priority Date: 05/12/1998
• Status: Expired due to Fees

• Current Assignee: Ultra Sonus AB
• Original Assignee: Ultra Sonus AB
• Inventors: Nilsson, Bo, Dahlberg, H.ang.kan
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/348,308
• Time in Patent Office: 475 Days
• Field of Search: 310/344, 310/346
• US Class Current: 310/346
• CPC Class Codes: A61B 8/546 involving monitoring or regulation of device temperature
• CPC Class Codes: B06B 1/06 operating with piezoelectric effect or with electrostriction piezoelectric or electrostrictive devices per se H10N30/00
• CPC Class Codes: B06B 1/0611 in a pile
• CPC Class Codes: G10K 11/004 Mounting transducers, e.g. provided with mechanical moving or orienting device mountings specially adapted to a particular sound-producing device, see the preceding groups G10K1/00 - G10K9/00, e.g. G10K1/26, G10K1/28, G10K9/22; arrangements of sonic watch equipment on submarines B63G8/39; buoys B63B22/00

Abstract

A method to improve the high output characteristics of a ultrasonic transducer 1 by urging a cooling gas 13 to flow through the transducer, thereby passing a cooling member 18 between at least one pair of adjacent piezoelectric elements 6, 7. In a preferred embodiment sulfurhexafluoride (SF₆) is used as cooling gas.

Claims

1. A method for improving the output of an ultrasonic transducer, the transducer being of the type employing at least two piezoelectric elements wherein the piezoelectric elements are stacked serially and an alternating voltage is applied to the opposing surfaces of the elements for that purpose of causing them to change their dimensions in response thereto, and the transducer further being of the type with the piezoelectric elements encased in a fluidum-tight casing and still further the transducer through its casing is provided with at least one inlet conduit for supplying a gas and at least one outlet conduit for discharging the gas,

the method comprising the steps of:

providing a gas conducting means between at least one pair of adjacent piezoelectric elements for cooling the piezoelectric elements, said gas conducting means provided with at least one channel providing a gas flow path through the gas conducting means, and said conducting means being so arranged that the inlet conduit is in flow communication with the inlet of said channel and the outlet of said channel is in flow communications with the outlet conduit;

selecting and providing a cooling gas;

forcing said cooling gas into the inlet conduit, thereby urging it to flow through said gas conducting means for cooling of the adjacent piezoelectric elements whereby the temperature of said cooling gas is raised, and discharging said cooling gas of elevated temperature through the outlet conduit.

2. The method according to claim 1, wherein said step of selecting a cooling gas includes the step of selecting said gas from the group of gases consisting of:

nitrogen, hydrogen, carbon dioxide, Freon 12, ammonia and sulfurhexafluoride SF₆.

3. The method according to claim 1, wherein said step of selecting a cooling gas further comprises the step of selecting said cooling gas according to its dielectrical properties in order to suppress arc over within the transducer.

4. The method according to claim 3, wherein said step of selecting a cooling gas of suitable dielectrical properties comprises the step of selecting sulfurhexafluoride (SF₆) as said cooling gas.

5. An ultrasonic transducer device employing at least two piezoelectric elements, wherein the piezoelectric elements are stacked serially and are provided with means for electrically connecting them to an alternating voltage source applied to the opposing surfaces of the elements for the purpose of causing them to change their dimensions in response thereto, and the piezoelectric elements are encased in a gas-tight casing, and at least one inlet conduit for supplying a gas and at least one outlet conduit for discharging the gas are provided through the casing, the ultrasonic transducer device comprising:

a gas conducting means disposed between at least one pair of adjacent piezoelectric elements for cooling the piezoelectric elements with a cooling gas, wherein said gas conducting means has least one central hole in flow communication with the outlet conduit, and an outer rim surface in flow communication with the outlet conduit, said gas conducting means further provided with at least one channel providing a gas flow path through the gas conducting means, between the inlet conduit and the outlet conduit.

6. The ultrasonic transducer device according to claim 5, wherein said gas conducting means is a metal disk element.

7. The ultrasonic transducer device according to claim 6, wherein said metal disk element is an assembly of a first disk shaped plate with a first central hole and a second disk shaped plate with a second central hole, said second disk shaped plate on one flat surface provided with at least one groove connecting the radial inner rim of the disk with its radial outer rim, and the plates are assembled such that the first plate covers the at least one groove to define a passage through the assembly.