Metering valve with viscosity gompensating adjustment

Claim 1

A FUEL OIL FLOW CONTROL DEVICE COMPRISING, A HOUSING HAVING AN INLET AND AN OUTLET, MEANS CONTROLLING FLOW THROUGH THE INLET TO MAINTAIN A CONSTANT LEVEL OF FUEL OIL IN THE HOUSING, A VERTICALLY EXTENDING UPFEED METERING PASSAGE HAVING AN ENTRANCE AND AN EXIT AND INTER-CONNECTING THE INLET AND THE OUTLET, VALVE MEANS CONTROLLING THE FLOW OF FUEL OIL THROUGH THE METERING PASSAGE, SAID VALVE MEANS INCLUDING AN ELONGATED SECTION MOUNTED FOR AXIAL MOVEMENT IN THE PASSAGE AND HAVING A PILOT FLOW CONTOUR, A HIGH FLOW CONTOUR, AND AN EXTENDING PORTION LOCATED BELOW SAID TWO CONTOURS AND TERMINATING AT THE END OF THE ELONGATED SECTION; THE EXTENDED SECTION COOPERATING WITH THE PASSAGE TO PRODUCE LAMINAR FLOW THROUGH THE PASSAGE, SAID PILOT FLOW CONTOUR AND HIGH FLOW CONTOUR EACH HAVING AN ARCUATE SURFACE TO PROVIDE A RAPID RISE CHARACTERISTIC IN THE FLOW RATE TO A SUBSTANTIALLY CONSTANT FLOW CHARACTERISTIC IN THE FLOW RATE, THE START OF THE HIGH FLOW CONTOUR BEING LOCATED RELATIVE TO THE PILOT FLOW CONTOUR TO PROVIDE A SUBSTANTIALLY CONSTANT FLOW RATE CHARACTERISTIC DURING THE MOVEMENT OF THE VALVE MEANS FROM PILOT FLOW TO THE START OF THE HIGH FLOW CONTOUR, AND SELECTIVELY MOVABLE ADJUSTMENT MEANS FOR VARYING THE RELATIVE VERTICAL POSITION BETWEEN THE INLET AND OUTLET OF THE HOUSING TO THEREBY PERMIT VARIANCE IN THE DIFFERENCE IN OIL PRESSURE BETWEEN THE POINTS AT THE ENTRANCE AND THE EXIT OF THE OIL INTO THE PASSAGE.