A device for treating flowing working gases in order to reduce their operational noises and in most instances also to increase their operating efficiency comprises a flowing working gas operating device which has a discharge conduit with at least one discharge opening for the outflow of the working gas. A check valve is associated with the discharge and includes an elastic valve member movable to close the opening when the flow thereof decreases to a predetermined amount for example as determined by the reduction of pressure of the gases so as to prevent any back flow into the conduit which is likely to produce noise. The elastic member may comprise an ordinary rubber band which is preferably held in position by a guide member so that when the pressure of the working gas is sufficient the gases will flow out of the discharge conduit and will be directed through one or more chambers so as to cause the gas to flow into a whirling vortex flow and preferably in a substantially annular path so as to order the gases and to thereby increase their efficiency of operation.

A flapper finger valve assembly for use in an exhaust system. The flapper finger valve includes a tube having a plurality of orifices therethrough. The flapper finger valve assembly also includes a plurality of flapper finger valves generally having a C-shape wherein the flapper finger valves are arranged on an outside surface of the tube. The flapper finger valves are capable of radial movement with respect to the tube. A plurality of retainers generally having a C-shape are arranged around the flapper finger valve. These retainers will define a maximum radial movement for such flapper finger valves on the tube. The flapper finger valve assembly also includes a fastener which will secure the flapper finger valves between a tube and retainers in the flapper finger valve assembly.