Fluid metering and sampling apparatus and controls therefor

Claim 1

IN A METERING AND SAMPLING APPARATUS WHEREIN A VESSEL HAS AN INLET AND AN OUTLET GOVERNED BY INLET AND OUTLET VALVES WHICH ARE ALTERNATELY OPENED AND CLOSED TO BATCH LIQUID THROUGH THE VESSEL AND WHEREIN A CROSS-SECTION SAMPLING DEVICE IS PROVIDED TO TAKE A SAMPLE FROM THE VESSEL WHILE IT IS FULL AND BEFORE IT IS EMPTIED, FIRST AND SECOND PISTONS RESPECTIVELY MOUNTED IN CYLINDERS AND CONNECTED RESPECTIVELY TO SAID SAMPLING DEVICE AND TO SAID INLET AND OUTLET VALVES SUCH THAT MOVEMENT OF THE FIRST PISTON IN ONE DIRECTION CAUSES THE SAMPLING DEVICE TO TAKE A SAMPLE AND MOVEMENT OF THE SECOND PISTON IN A FIRST DIRECTION CLOSES THE INLET VALVE AND OPENS THE OUTLET VALVE AND IN A SECOND DIRECTION OPENS THE INLET VALVE AND CLOSES THE OUTLET VALVE, A THREE-WAY PILOT VALVE CONNECTED TO CONTROL FLOW OF ACTUATING FLUID TO SAID PISTON AND POSITIONABLE IN SECOND, THIRD AND FIRST POSITION TO RESPECTIVELY APPLY ACTUATING FLUID TO THE FIRST PISTON, APPLY ACTUATING FLUID TO THE SECOND PISTON AND INTERRUPT THE APPLICATION OF ACTUATING FLUID AS AFORESAID, MEANS APPLYING FORCE TO MOVE THE PILOT VALVE FROM ITS FIRST TO ITS SECOND AND THEN TO ITS THIRD POSITIONS RESPONSIVE TO SAID VESSEL BECOMING FILLED, MEANS NORMALLY PREVENTING MOVEMENT OF THE PILOT VALVE FROM ITS SECOND TO ITS THIRD POSITION AND RELEASABLE TO PERMIT SUCH MOVEMENT RESPONSIVE TO SAID FIRST PISTON MOVING IN SAID ONE DIRECTION UNTIL THE SAID SAMPLING DEVICE HAS COMPLETED THE TAKING OF A SAMPLE, AND MEANS FOR MOVING THE PILOT VALVE FROM ITS THIRD TO ITS FIRST POSITION RESPONSIVE TO EMPTYING OF SAID VESSEL.