Abstract: A sound attenuation device for internal combustion engines includes a tubular core extending from an inlet end to an outlet end and having apertures formed therethrough to allow fluid communication between the interior and the exterior of the tubular core. One or more flanges position the tubular core in an exhaust passageway and are provided with apertures so that exhaust flowing through the exhaust passageway can flow either through the tubular core or through the flange apertures. End caps may be employed to close the inlet end of the tubular core and to provide a reduced diameter opening at the outlet end thereof.

Abstract: A two-way pressure relief assembly includes a disk having a peripheral flange for clamping the disk between inlet and outlet clamps in a passageway. The inlet side of the disk has a selected inlet relief pressure which will cause the flange and disk to pull out from between the inlet and outlet clamps and move toward the outlet side. The outlet side of the disk has an outlet relief pressure which will cause the flange and disk to pull out from between the inlet and outlet clamps and move toward the inlet side. A pressure support may be clamped between the disk flange and the inlet clamp for increasing the outlet relief pressure to a selected magnitude. The open center of the pressure support may be enlarged to decrease the outlet relief pressure or reduced to increase the outlet relief pressure. Support members may be extended across the central portion of the pressure support for increasing the outlet relief pressure. Inlet and outlet gaskets may be provided on the corresponding sides of the disk.