Generating device for generating a useful stream of a medium, in particular for generating sound

1. A generating device ( 1 ) for generating a useful stream of a medium ( 2 ) comprising:

at least a medium stream source ( 14 ) for generating at least a medium stream ( 15 ) in mutually opposed flow directions ( 16 ), modulating a first signal laying within a first frequency range to generate a second signal laying within a second frequency range, and alternating the mutually opposed flow directions ( 16 ) of the medium stream with the second signal lying within the second frequency range, said second frequency range covering frequencies that lie above those of the first frequency range;

at least a medium stream diode ( 22 ; 25 ; 36 , 37 ) provided, constructed and arranged for cooperating with a stream of a medium generated by the at least one medium stream source working counter to said stream of the medium with flow resistances, and generating a total medium stream flowing in a transmission direction of the at least one medium stream diode; and

at least one medium stream sink ( 23 , 24 ; 40 , 41 ) provided, constructed, and arranged for cooperating with the total medium stream generated by the at least one medium stream diode, suppressing stream components within the second frequency range contained in the total medium stream, and generating the useful stream of the medium ( 2 ) in the first frequency range without the stream components within the second frequency range at an output of the at least one medium stream sink ( 23 ; 40 ).

2. A generating device ( 1 ) as claimed in claim 1 , wherein the generating device ( 1 ) is designed for generating a useful flow of air ( 2 ).

3. A generating device ( 1 ) as claimed in claim 2 , wherein the generating device ( 1 ) comprises at least one ultrasound source ( 14 ) as the medium stream source, at least one acoustic diode ( 22 ; 25 ; 36 , 37 ) as the medium stream diode, and at least one ultrasound sink ( 23 , 24 ; 40 , 41 ) as the medium stream sink.

4. A generating device ( 1 ) as claimed in claim 3 , wherein the ultrasound source ( 14 ) comprises a signal generator ( 20 ) for generating a carrier signal (CS) with an ultrasound frequency (f US ), wherein the signal generator ( 20 ) in addition comprises at least one connection terminal ( 21 ) for the supply of a useful signal (S UF ) with a frequency spectrum lying substantially in the audible range, and wherein the signal generator ( 20 ) is designed for modulating the carrier signal (CS) in dependence on the useful signal (S UF ).

5. A generating device ( 1 ) as claimed in claim 4 , wherein the signal generator ( 20 ) is designed for generating a carrier signal (CS) with an ultrasound frequency (f US ) whose value is at least ten times the value of the highest frequency in the useful signal.

6. A generating device ( 1 ) as claimed in claim 3 , wherein two ultrasound sinks ( 23 , 24 ; 40 , 41 ) are provided.

7. A generating device ( 1 ) as claimed in claim 3 , wherein a plurality of acoustic diodes ( 36 , 37 ) are provided.

8. A generating device ( 1 ) as claimed in claim 7 , wherein at least one air flow chamber ( 30 ; 30 , 35 ) extending parallel to the mutually opposed flow directions ( 16 ) is provided, wherein the at least one air flow chamber has at least one boundary wall that extends parallel to the mutually opposed flow directions ( 16 ) and that is formed by a membrane ( 31 ) of the ultrasound source ( 14 ), wherein the membrane is capable of vibration, and wherein the at least one air flow chamber has at least one boundary wall ( 32 , 33 ) that extends transversely to the mutually opposed flow directions ( 16 ) and that comprises a plurality of acoustic diodes ( 36 , 37 ), while a sink chamber ( 40 , 41 ) forming an ultrasound sink is provided at least one boundary wall ( 32 , 33 ) comprising a plurality of acoustic diodes ( 36 , 37 ).

9. A generating device ( 1 ) as claimed in claim 8 , wherein the two boundary walls ( 32 , 33 ) of the at least one air flow chamber ( 30 ; 30 , 35 ) extending transversely to the mutually opposed flow directions ( 16 ) comprise a plurality of acoustic diodes ( 36 , 37 ), and wherein a sink chamber ( 40 , 41 ) forming an ultrasound sink is provided adjoining the two boundary walls ( 32 , 33 ) of the at least one air flow chamber ( 30 ; 30 , 35 ) extending transversely to the mutually opposed flow directions ( 16 ).

10. A generating device ( 1 ) as claimed in claim 8 , wherein the acoustic diodes ( 22 ) comprise funnel-shaped holes (H) that are formed so as to generate turbulent air flows.

11. A generating device ( 1 ) as claimed in claim 1 , wherein all components of the generating device ( 1 ) are manufactured from solid state elements capable of integration in integrated technology.