Duct sound damper for a flow machine

1. A duct sound damper for deliberate reduction of sound waves for a flow machine, particularly for a compressor, comprising:

a housing comprising at least one horizontally extending acoustically reflective back wall;

at least one front cover plate; at least one flow channel connected together through an inlet opening and an outlet opening enclosed by at least one damper member reducing the sound, the damper member comprising:

first horizontal axial stringers;

first circumferential stringers whose major dimension extends horizontal to the flow guiding cross section:

the front cover plate;

at least one sound-insulating metal element extending horizontal to the flow-guiding cross section; and the acoustically reflective back wall.

2. The duct sound damper according to claim 1 , wherein the sound-insulating metal element is perforated sheet metal.

3. The duct sound damper according to claim 1 , wherein the axial stringers, the circumferential stringers, and the cover plate are connected to one another by snap-in connections.

4. The duct sound damper according to claim 2 , wherein the axial stringers, the circumferential stringers, and the cover plate are inserted one inside the other by projections and slots.

5. The duct sound damper according to claim 1 , further comprising an outer damper member.

6. The duct sound damper according to claim 1 , further comprising an outer damper member and a middle damper member.

7. The duct sound damper according to claim 5 , wherein the outer damper member and middle damper member are fixedly connected to a supporting cross at least at one of the inlet end and outlet end.

8. The duct sound damper according to claim 1 , further comprising an outer damper member, a middle damper member, and a central damper member.

9. The duct sound damper according to claim 7 , wherein the outer damper member, the middle damper member, and the central damper member are fixedly connected to the supporting cross at least at the inlet end and outlet end.

10. The duct sound damper according to claim 7 , wherein the supporting crosses are fixedly connected to the sound-insulating metal element.

11. The duct sound damper according to claim 1 , wherein the damper member is constructed in a doubled manner, second axial stringers and second circumferential stringers separated by an acoustically reflective back wall form a second, parallel damper member.

12. The duct sound damper according to claim 1 , wherein the acoustically

reflective back wall is fixedly connected to the cover plates.

13. A method for the installation of the duct sound damper according to claim 1 in a flow duct of a flow machine comprising:

Arranging at least one compensation plate at the outer circumference of the acoustically reflective back wall; and compensating for a non-round flow duct.

14. The method for the installation of a duct sound-damper in a flow duct of a flow machine according to claim 13 , further comprising arranging at least one spherical roller under spring force circumferentially at the flow end of a duct sound damper element at the acoustically reflective back wall to support the duct sound damper in the flow duct.

15. The method for the installation of a duct sound-damper in a flow duct of a flow machine according to claim 14 , wherein the spring force acts substantially vertically in direction of the inner wall of the flow duct.

16. The duct sound damper according to claim 1 , further comprising at least one spherical roller under spring force is arranged circumferentially at the flow end of a duct sound damper element at the acoustically reflective back wall thereof to support the duct sound damper in the flow duct.