Patent ID: 7936641

Claim:
A device for generating an acoustic signal in a fluid, the device comprising: a body having a cylindrical shape; a chamber disposed within the body and operable to contain a chemical reaction that generates heat to generate pressure inside the chamber; an intake valve operable to open the chamber to allow a reactant to be inserted into the chamber, and operable to close the chamber to cause the heat from the chemical reaction to generate pressure inside the chamber; an exhaust valve operable to open the chamber to release mass from inside the chamber to decrease pressure inside the chamber, and operable to close the chamber to cause the heat from the chemical reaction to generate pressure inside the chamber; a membrane having a portion that is operable to move in response to a pressure change inside the chamber, wherein the portion moves in a first direction while the pressure inside the chamber increases, and the portion moves in a second direction while the pressure inside the chamber decreases; and wherein the increase and decrease of pressure inside the chamber can be repeated by the device to vibrate the membrane portion in the first and the second directions to generate an acoustic signal having more than one period.