Piston means for damping noise and/or vibrations in rotary fluid machines

Claim 1

A ROTARY MACHINE HAVING A CASING, A ROTOR MEANS ROTATABLY MOUNTED IN SAID CASING AND INCLUDING A PLURALITY OF WORKING CHAMBERS PERIODICALLY INCREASING AND DECREASING THEIR VOLUME, THEREBY INTAKING AND EXPELLING FLUID, DURING OPERATION OF THE MACHINE UNDER POWER, A SUBSTANTIALLY STATIONARY CONTROL BODY HAVING A STATIONARY CONTROL FACE FOR COOPERABLE WITH A COMPLEMENTARY ROTARY CONTROL FACE ON SAID ROTOR MEANS, ROTOR PASSAGE MEANS EXTENDING FROM SAID WORKING CHAMBERS THROUGH SAID ROTOR INTO AND THROUGH SAID COMPLEMENTARY ROTARY CONTROL FACE, AT LEAST A PAIR OF SPACED CONTROL PORTS FORMED IN SAID STATIONARY CONTROL FACE, AND WORKING CHAMBER CLOSING ARC FACES LOCATED ON SAID STATIONARY CONTROL FACE BETWEEN SAID CONTROL PORTS, SAID CLOSING FACES PERIODICALLY CLOSING AT LEAST ONE ROTOR PASSAGE OF SAID ROTOR PASSAGE MEANS DURING ROTATION OF SAID ROTOR MEANS, FLUID PASSAGES EXTENDING FROM RESPECTIVE ENTRANCE AND EXIT PORTS THROUGH SAID CONTROL BODY INTO RESPECTIVE CONTROL PORTS OF SAID CONTROL PORT PAIR, CYLINDER MEANS IN SAID MACHINE, POSTON MEANS RECIPROCABLE IN SAID CYLINDER MEANS, COMMUNICATION-PASSAGE MEANS EXTENDING FROM SAID CYLINDER MEANS TO AND THROUGH AT LEAST ONE OF SAID CLOSING ARC FACES, AND AT LEAST ANOTHER COMMUNICATIONPASSAGE MEANS EXTENDING FROM ANOTHER PART OF SAID CYLINDER MEANS INTO A RESPECTIVE SPACE IN SAID ROTARY MACHINE, THE SURFACE OF ONE OF SAID CYLINDER MEANS AND PISTON MEANS BEING FORMED WITH RECESS MEANS EXTENDING LONGITUDINALLY THEREOF FOR RESTRICTED FLUID FLOW LONGITUDINALLY BETWEEN SAID CYLINDER MEANS AND SAID PISTON MEANS.