Flow control mechanism

Claim 1

FOR COMBINATION WITH AN AIRCRAFT CHAMBER TO WHICH AIR IS SUPPLIED FOR PRESSURIZATION AT DIFFERENT ALTITUDES, AN IMPROVED ASSEMBLY FOR CONTROLLING DISCHARGE FLOW OF GAS FROM SAID CHAMBER TO THE EXTERIOR, SAID ASSEMBLY COMPRISING A FLOW CONDUIT COMMUNICABLE WITH SAID CHAMBER AND THE EXTERIOR, A VALVE IN THE FORM OF A DAMPER MOUNTED FOR PIVOTAL MOVEMENT IN LENGTHWISE EXTENT OF THE CONDUIT TO DECREASE THE FLOW AREA OF MAIN ORIFICES WITHIN SAID CONDUIT ALL IN RESPONSE TO INCREASING DIFFERENTIAL AIR PRESSURE UPSTREAM AND DOWNSTREAM OF THE VALVE, THE VALVE HAVING A PIVOT AXIS GENERALLY TRANSVERSE OF THE CONDUIT LENGTHWISE EXTENT, SAID MAIN ORIFICES BEING FORMED BETWEEN THE CONDUIT BORE AND TERMINAL EDGES OF THE VALVE RESPECTIVELY SPACED UPSTREAM AND DOWNSTREAM FROM SAID PIVOT AXIS WHEN THE VALVE IS OPEN, MEANS UPSTREAM OF THE VALVE AND OPERABLE TO DISPLACE AIR TO FLOW DOWNSTREAM AGAINST AND TENDING TO CLOSE THE VALVE, AND MEANS FOR INCREASINGLY YIELDABLY RESISTING SAID VALVE PIVOTAL MOVEMENT AS THE VALVE PIVOTS TO CLOSE SAID MAIN ORIFICES, SAID ASSEMBLY FORMING AUXILIARY ORIFICE MEANS AT THE VALVE FOR PASSING AIR FLOWING FROM THE UPSTREAM SIDE TO THE DOWNSTREAM SIDE THEREOF, SAID AUXILIARY ORIFICE MEANS BEING SIZED TO PASS THE FLOW SUPERSONICALLY WHEN THE MAIN ORIFICES ARE CLOSED IN RESPONSE TO SUFFICIENT AIR DISPLACEMENT DOWNSTREAM AND AGAINST THE VALVE, THE FLOW AREA OF SAID AUXILIARY ORIFICE MEANS REMAINING SUBSTANTIALLY INDEPENDENT OF PIVOTAL MOVEMENT OF SAID VALVE AS THE VALVE APPROACHES CLOSED POSITION, WHEREBY AS SAID DIFFERENTIAL AIR PRESSURE INCREASES THE MASS FLOW OF AIR THROUGH SAID CONDUIT REMAINS SUBSTANTIALLY CONSTANT.