Air distribution apparatus

Claim 1

FOR USE IN AIR DISTRIBUTION APPARATUS, A FLOW CONTROL DEVICE COMPRISING A HOUSING DEFINING A SUBSTANTIALLY RECTANGULAR AIR PASSAGEWAY HAVING TOP AND BOTTOM WALLS AND OPPOSITELY FACING SIDE WALLS, A FLAT IMPERFORATE SUBSTANTIALLY RECTANGULAR VALVE MEMBER EXTENDING BETWEEN THE SIDE WALLS OF SAID AIR PASSAGEWAY AND INCLINED UPWARDLY IN THE UPSTREAM DIRECTION WITH ITS LOWER EDGE PORTION PIVOTALLY SUPPORTED ADJACENT THE BOTTOM WALL OF THE PASSAGEWAY SO THAT UPSTREAM AIR PRESSURE TENDS TO PIVOT THE SAME THROUGH AN ARC FROM A FIRST ANGULAR POSITION WHEREIN ITS UPPER EDGE PORTION IS DISPOSED ABOVE AND UPSTREAM OF ITS SAID LOWER EDGE PORTION TO A SECOND ANGULAR POSITION WHEREIN SAID UPPER EDGE PORTION IS DISPOSED ABOVE AND DOWNSTREAM OF SAID FIRST POSITION, RESILIENT BIASING MEANS OPERATIVELY CONNECTED WITH SAID VALVE MEMBER AND OPPOSING THE FORCE EXERTED THEREON BY UPSTREAM AIR PRESSURE SO AS TO PROVIDE FOR MOVEMENT OF SAID VALVE MEMBER IN ACCORDANCE WITH A PREDETERMINED SCHEDULE WHEREBY A CONSTANT RATE OF INCREASE IN UPSTREAM AIR PRESSURE EFFECTS PIVOTAL MOVEMENT OF SAID VALVE MEMBER FROM SAID FIRST TO SAID SECOND ANGULAR POSITION AT A DECREASING RATE OF MOVEMENT, AND A GENERALLY ARCUATELY SHAPED ORIFICE PLATE EXTENDING ACROSS SAID PASSAGEWAY WITH ITS UPPER EDGE PORTION DISPOSED ABOVE AND DOWNSTREAM OF ITS LOWER EDGE PORTION AND HAVING ORIFICES THEREIN WHICH ARE CLOSED PROGRESSIVELY BY SAID VALVE MEMBER DURING MOVEMENT OF THE LATTER FROM SAID FIRST TO SAID SECOND POSITION, THE SIZE AND SHAPE OF SAID ORIFICES BEING SUCH THAT VALVE MOVEMENT EFFECTED BY INCREASING AIR PRESSURE DECREASES THE TOTAL ORIFICE AREA OPEN TO AIR FLOW AT A RATE IN EXCESS OF THE RATE OF VALVE MOVEMENT AND IN ACCORDANCE WITH A PREDETERMINED SCHEDULE WHEREBY TO PROVIDE FOR A SCHEDULE OF DECREASING ORIFICE AREA WITH INCREASING AIR PRESSURE WHICH RESULTS IN A SUBSTANTIALLY CONSTANT FLOW OF AIR THROUGH THE DEVICE.