Liquid level control valve

Claim 1

IN COMBINATION WITH A TANK, VALVE MEANS FOR CONTROLLING THE FLOW OF LIQUID TO AND FROM THE TANK TO MAINTAIN THE LIQUID LEVEL THEREIN BETWEEN PRESELECTED UPPER AND LOWER LEVELS, SAID VALVE MEANS INCLUDING A DIAPHRAGM HAVING ONE SIDE EXPOSED TO ATMOSPHERIC PRESSURE, A VALVE MEMBER ENGAGEABLE WITH SAID DIAPHRAGM AND MOVABLE THEREWITH, CONDUIT MEANS ESTABLISHING CONTINOUS OPEN COMMUNICATION BETWEEN THE OTHER SIDE OF SAID DIAPHRAGM AND SAID TANK TO APPLY FLUID PRESSURE TO THE DIAPHRAGM CORRELATIVE WITH THE LIQUID LEVEL IN THE TANK WHEREBY TO MOVE THE DIAPHRAGM AND VALVE MEMBER FROM A SECOND POSITION WHEN THE LIQUID IN THE TANK IS BELOW A PRESELECTED UPPER LEVEL TO A FIRST POSITION WHEN THE LIQUID IN THE TANK IS AT SAID PRESELECTED UPPER LEVEL, A FLOW PASSAGE ADAPTED TO HAVE LIQUID FLOW IN ONE DIRECTION THERETHROUGH TO FILL THE TANK AND TO HAVE LIQUID FLOW IN THE OTHER DIRECTION THERETHROUGH TO WITHDRAW LIQUID FROM THE TANK, SAID PASSAGE HAVING A FLOW AREA WHICH IS SMALL AS COMPARED TO THE FLOW AREA OF SAID CONDUIT MEANS WHEREBY TO MAINTAIN THE PRESSURE IN SAID CHAMBER CORRELATIVE WITH THE LIQUID LEVEL IN SAID TANK AS LIQUID FLOWS IN SAID ONE DIRECTION THROUGH SAID PASSAGE, MEANS IN SAID PASSAGE DEFINING A VALVE SEAT, SAID VALVE MEMBER EXTENDING INTO SAID PASSAGE AND HAVING A VALVE FACE ENGAGEABLE WITH SAID SEAT WHEN SAID MEMBER IS MOVED IN SAID ONE DIRECTION IN SAID PASSAGE TO SAID FIRST POSITION WHEREBY TO BLOCK