de frees

Claim 1

MEANS OF THE CHARACTER DESCRIBED FOR CONTROLLING LIQUID DISCHARGE FROM A WALLED ENCLOSURE HAVING A DRAIN POCKET DEPRESSION IN A LOWER WALL PORTION THEREOF AND A PORT APERTURE IN SAID DEPRESSION, SAID PORT APERTURE IN SAID DEPRESSION HAVING A PERIPHERAL EDGE PORTION ADAPTED TO SERVE AS A VALVE SEAT, AN EMERGENCY VALVE STRUCTURE DISPOSED WITHIN SAID ENCLOSURE ABOVE AND ADJACENT TO SAID PORT, SAID VALVE STRUCTURE COMPRISING A CYLINDER, A PLURALITY OF LEGS SUPPORTING SAID CYLINDER AND ATTACHED TO SAID DRAIN POCKET AT RESPECTIVE LOCATIONS SPACED AROUND SAID PORT, A PISTON MOVABLE IN SAID CYLINDER, A DISCHARGE VALVE ADAPTED FOR VERTICAL MOVEMENT, INTO AND OUT OF SEALING RELATIONSHIP WITH SAID VALVE SEAT, MEANS ESTABLISHING AN OPERATIVE CONNECTION BETWEEN SAID PISTON AND SAID VALVE WHEREBY APPROPRIATE MOVEMENT OF SAID PISTON LIFTS SAID VALVE OUT OF SEALING ENGAGEMENT WITH SAID VALVE SEAT, ONE OF SAID LEGS HAVING A PASSAGE THERETHROUGH TO ESTABLISH AIR FLOW COMMUNICATION WITH SAID CYLINDER, AND MEANS FOR ADMITTING COMPRESSED AIR TO AND THROUGH SAID PASSAGE WHEN SAID VALVE IS TO BE OPENED, EACH OF SAID LEGS BEING OF ELONGATED TRANSVERSE SECTIONAL CONTOUR, THE LONGEST DIMENSION OF THE TRANSVERSE SECTION EXTENDING IN THE DIRECTION OF LIQUID DISCHARGE FLOW TO SAID PORT WHEREBY TO REDUCE TURBULENCE AND PROMOTE SWIRL-FREE LIQUID DISCHARGE, SAID LEGS BEING WITHIN SAID ENCLOSURE ON THE IN-FLOW SIDE OF SAID PORT.