Adjustable xx le level

Claim 1

AN AUTOMATIC GATE FOR CONTROLLING THE FLOW OF LIQUID THROUGH A PASSAGEWAY CONNECTING AN UPSTREAM REACH WITH A DOWNSTREAM REACH SO AS TO MAINTAIN CONSTANT THE LEVEL OF LIQUID IN SUCH DOWNSTREAM REACH, COMPRISING A VERTICALLY DISPOSED CLOSING BODY HAVING AN UPPER SECTION, A LOWER SECTION, A REDUCED SECTION INTERMEDIATE SAID UPPER AND LOWER SECTIONS AND HAVING A CROSS-SECTIONAL AREA TRANSVERSE TO THE VERTICAL AXIS OF SAID CLOSING BODY SUBSTANTIALLY LESS THAN THE TRANSVERSE AREAS OF SAID UPPER AND LOWER SECTIONS SAID UPPER SECTION BEING PROVIDED WITH A LIQUID CHAMBER WHICH NORMALLY EXTENDS UPWARDLY FROM A LEVEL ABOVE THE LEVEL OF THE DOWNSTREAM REACH AND SUBSTANTIALLY BELOW THE LEVEL OF THE UPSTREAM REACH TO A HEIGHT ABOVE THE LATTER, AND WHICH HAS A BOTTOM WALL PROVIDING A TRANSVERSE AREA SUBSTANTIALLY GREATER THAN SAID TRANSVERSE AREA OF SAID REDUCED SECTION AND THROUGH THE CENTER OF WHICH PASSES SAID VERTICAL AXIS, MEANS BRINGING SAID CHAMBER INTO COMMUNICATION WITH THE LIQUID IN SAID UPSTREAM REACH TO PROVIDE IN SUCH CHAMBER A LIQUID MASS HAVING A LIQUID LEVEL CONFORMING TO THE LEVEL OF THE UPSTREAM REACH, SAID LOWER SECTION BEING WHOLLY IMMERSED IN THE LIQUID OF SAID DOWNSTREAM REACH TO CONTROL THE DISCHARGE OF THE LIQUID FROM SAID PASSAGEWAY INTO THE DOWNSTREAM REACH, SAID LOWER SECTION HAVING A TRANSVERSE AREA SUBJECTED TO HYDRAULIC THRUST OF SAID REACHES SUBSTANTIALLY EQUAL TO THE AREA OF SAID CHAMBER BOTTOM WALL AND THROUGH THE CENTER OF WHICH PASSES SAID VERTICAL AXIS, SAID INTERMEDIATE SECTION BEING PARTLY IMMERSED IN THE LIQUID OF SUCH DOWNSTREAM REACH AND BEING OF A HEIGHT GREATER THAN THE NORMAL RISE AND FALL OF THE LEVEL OF SAID DOWNSTREAM REACH, AND SAID UPPER SECTION BEING POSITIONED ABOVE THE LEVEL OF SAID DOWNSTREAM REACH AND BEING OF SUCH HEIGHT THAT ITS UPPER END AND THE TRANSVERSE BOTTOM WALL OF SAID CHAMBER ASSOCIATED THEREWITH WILL BE ABOVE AND BELOW, RESPECTIVELY, THE NORMAL RISE AND FALL OF THE LEVEL OF SAID UPSTREAM REACH, AND MEANS FOR SUPPLYING A FORCE IN OPPOSITION TO A RESULTANT OF THE HYDRAULIC FORCES ON SAID TRANSVERSE WALLS OF SAID CLOSING BODY.