| 摘要 |
PCT No. PCT/SE88/00172 Sec. 371 Date Oct. 6, 1989 Sec. 102(e) Date Oct. 6, 1989 PCT Filed Apr. 8, 1988 PCT Pub. No. WO88/07894 PCT Pub. Date Oct. 20, 1988.Air-driven, low-frequency sound generator with a positive feedback system, comprising, as a sound emitter, an open resonator (11) for the generation of standing gas-borne sound waves which produce a varying gas pressure inside the resonator; and feeder (10) with a tube (14) for the supply of pressure gas to the resonator and a back and forth movable springing valve slide (15) whose position remains unaffected by the pressure gas and which regulates the gas flow from the tube while creating a modulated flow of pressure to the resonator. The tube is surrounded by a surge tank (13), connected to the pressure gas source, and the valve slide is arranged as a piston movable inside the tube and is set to regulate a connecting opening (20) between the surge tank and the inside of the tube. This opening is situated at one end surface (19) of the piston and said end surface is being exposed to the inside of the resonator by means of the one end of the tube communicating therewith. |
