Adjustable muffler

Claim 1

AN ADJUSTABLE MUFFLER FOR GASES COMPRISING A CASING HAVING AN INLET AND AN OUTLET, A PLURALITY OF SPACED APART BAFFLES IN THE CASING FORMING SEPARATE COMPARTMENTS, SAID BAFFLES HAVING REGISTERING OPENINGS THERETHROUGH, A FIRST TUBE RECEIVED IN SAID REGISTERING OPENINGS AND SEALING SAID OPENINGS, SAID FIRST TUBE HAVING OPENINGS THEREIN BETWEEN EACH PAIR OF BAFFLES, A SECOND TUBE ROTATABLY RECEIVED IN THE FIRST TUBE, SAID SECOND TUBE HAVING OPENINGS IN ANNULAR ALIGNMENT WITH THE OPENINGS OF THE FIRST TUBE AND DEFINING THEREWITH ORIFICES FOR PASSAGE OF GASES IN EITHER DIRECTION BETWEEN SAID COMPARTMENTS AND TUBES, SAID FIRST AND SECOND TUBES BEING OPEN ENDED, ONE END OF SAID TUBES RECEIVING GASES FROM THE CASING INLET AND THE OTHER ENDS OF THE TUBES DISCHARGING GASES TO THE CASING OUTLET, A SHAFT EXTENDING FROM A POINT EXTERIOR OF THE CASING INTO CONNECTION WITH THE SECOND TUBE, SEALING MEANS EFFECTING A GAS-TIGHT SEAL BETWEEN THE SHAFT AND CASING, A SEALING CAP OVER THE EXTERNAL PORTION OF THE SHAFT TO EFFECT AN ADDITIONAL GAS-TIGHT SEAL, SAID SHAFT BEING ROTATABLE BY ACTUATION THEREOF EXTERNALLY OF THE CASING TO MOVE THE OPENINGS OF THE SECOND TUBE INTO AND OUT OF REGISTRY WITH THE OPENINGS OF THE FIRST TUBE TO VARY THE ORIFICE SIZE DEFINED THEREBY.