Patent ID: 9739296
Date: 2017-08-22
CPC Classifications: B62D,F01N,F02C,F05D,F15D,F41A,F42B,G10K,Y10T

Claim:
1. A tube for assisting gas flow between an inlet end opening where gas is introduced and an outlet end opening through which gas exits the tube and for suppressing noise accompanying the gas movement which comprises: a closed chamber intermediate between the opening and exhaust ends for receiving the gas from the inlet, which closed chamber has an overall volume which permits expansion of the entry gas; wherein the closed chamber presents to the gas flow a series of waveguides arranged successively in an axial direction and inclined inwardly from interior walls of the closed chamber generally in the direction of flow that leave an unobstructed path for gas flow from the inlet end to the outlet end; the waveguides defining a plurality of annular guide cavities between successive inwardly extending edges of the waveguides and the outer wall of the chamber each annular guide cavity having at least a volume upstream of the guide edge and a cavity mouth open to the unobstructed path; the waveguides being sized and spaced such that gas vortices are created within the annular guide cavities when gas flow occurs, which vortices create a fluid boundary layer that moves past the guide edges and cavity mouths more slowly in the direction of flow than the unobstructed fluid flow more remote from the cavity mouths; wherein each waveguide comprises an inner wall with concave curvature on a gas inlet end and convex curvature on a gas outlet end and has an inflection point of curvature axially downstream of the inlet of the respective waveguide; and wherein an effective radius of the boundary layer is either constant or decreases with distance from the inlet end.