Multiple flow marine muffler constructed of resilient material

Claim 1

A multiple flow marine muffler constructed of resilient material, comprising: an elongated generally cylindrical hollow shell having an inlet portion of reduced diameter for attachment to an engine exhaust pipe and an outlet portion of generally the same reduced diameter; longitudinally spaced pairs of diametrically opposed spaced baffles disposed transversely within and supported by said hollow shell and defining a plurality of chambers decreasing in axial length from the chamber adjacent said inlet portion to the chamber adjacent said outlet portion, said baffles and the openings between the opposed baffles of each pair providing multiple flow paths for exhaust gases and cooling water, namely, a generally central straight through path for engine idle condition, a first pair of undulating paths in side by side out of phase relation and a second pair of undulating paths in side by side out of phase relation, said second pair oriented in said cylindrical shell 90° away from said first pair, the openings between each pair of opposed baffles which separate adjacent chambers being at least equal in total area to the cross-sectional area of said inlet portion, whereby back pressure is minimized and noise is modulated from high volume high frequency to low volume low frequency due to gas expansion and energy reflections in said chambers of decreasing length which result in energy cancellations and to the energy-absorbing characteristics of the component resilient material.