Air curtain

Claim 1

APPARATUS FOR ESTABLISHING AND MAINTAINING A MOVING CURTAIN OF AIR TRANSVERSELY OF A DOOR OPENING LEADING TO A ROOM REFRIGERATED TO TEMPERATURES BELOW 32* F., WHICH AIR CURTAIN IS OF SUFFICIENT VELOCITY AND DIRECTION TO RETARD ESCAPE OF REFRIGERATED AIR FROM THE SAID ROOM AREA AND EXCLUDE ENTRANCE OF DUCT AND INSECTS, COMPRISING, (A) A VERTICALLY DISPOSED AIR DISCHARGE DUCT DISPOSED ADJACENT ONE SIDE OF THE SAID DOOR OPENING AND PROVIDED WITH A VERTICALLY EXTENDING OPENING DIRECTING A HIGH VELOCITY VERTICAL AIR STREAM ACROSS THE FULL HEIGHT THEREOF AND TOWARDS A VERTICALLY DISPOSED AIR RECEIVING DUCT LOCATED ADJACENT THE OPPOSITE VERTICAL SIDE OF SAID OPENING FOR RESTRICTING PASSAGE OF COLD AIR FROM SAID ROOM, MEANS FOR ADJUSTABLY MOUNTING SAID AIR DISCHARGE DUCT, (B) A VETICALLY DISPOSED AIR RECEIVING DUCT ADJACENT THE OPPOSITE SIDE OF SAID DOOR OPENING COMPRISING A FRONT FACE DEFINED BY A CONTINUOUS VERTICAL RECTANGULAR SHAPED OPENING OF SUBSTANTIALLY THE WIDTH OF THE ADJACENT AIR CURTAIN TO BE RECEIVED THEREIN AND OF A HEIGHT SUBSTANTIALLY THAT OF SAID DOOR OPENING, REARWARDLY CONVERGING SIDEWALLS AT OPPOSITE SIDES OF SAID RECTANGULAR SHAPTED OPENING DEFINING A VERTICAL CONSTRICTED THROAT OPENING, A VERTICALLY EXTENDING AIR COLLECTING AND TRANSMITTING CHAMBER HAVING A CLOSED BOTTOM PORTION AND A TOP PORTION CONNECTING WITH SAID THROAT OPENING, AND (C) AIR CONDUIT MEANS CONNECTING SAID DUCTS AND EMBODYING SUITABLE FAN MEANS TO DRAW AIR IN THE DESIRED VOLUME THROUGH SAID RECEIVING DUCT AND DISCHARGE IT AT THE DESIRED VELOCITY THROUGH SAID DISCHARGE DUCT TO MAINTAIN AN AIR CURTAIN OF THE DESIRED CHARACTERISTICS.