Abstract: An acoustic filter adapted to be fitted on a pipe for the purpose of absorbing pressure waves. The acoustic filter has a body constituted by a cylinder, an inlet and outlet end, a locking ring fitted in a groove located at the inlet and outlet ends, coupling means within the locking rings for coupling the filter to a pipe. A holder tube fitted with diffuser rings for connecting the coupling means. A deformable bag made from a flexible material is mounted between the inlet and outlet ends, shaped like a cylindrical sleeve and surrounds the holder tube and diffuser rings. The bag defines with an inner wall of the cylinder a chamber for receiving a pressurized gas.

Abstract: It has an inlet and an outlet, a bag made from a flexible, deformable material insulating the inlet from the outlet, a liquid contained in the bag on the outlet side, a transfer tube with openings on its side wall and closed by an end plug. Diffusers are positioned on the transfer tube with a given spacing, so as to leave a passage for a gas between two successive diffusers, each diffuser comprising a frame externally surrounded by an elastomer ring.