Photoelectric dual pump control providing a constant combined output

Claim 1

IN A GRADIENT PRODUCING DEVICE, A PUMP ASSEMBLY HAVING A CONSTANT GIVEN OUTPUT, A CURVE AND CURVE FOLLOWER ASSEMBLY, A SERVO SYSTEM DRIVE ASSEMBLY CONNECTED TO THE PUMP AND CURVE AND CURVE FOLLOWER ASSEMBLIES, THE PUMP ASSEMBLY COMPRISING A PAIR OF VARIABLE VOLUME PUMPS, A DRIVE FOR THE PUMPS, ADJUSTMENTS FOR VARYING THE CAPACITY OF EACH OF THE PUMPS SO THAT THE PUMP ASSEMBLY OUTPUT IS CONSTANT, AND MEANS FOR MOVING THE ADJUSTMENTS, THE CURVE AND CURVE FOLLOWER ASSEMBLY COMPRISING A CYLINDRICAL DRUM HAVING A LONGITUDINAL AXIS, A DRIVE FOR THE DRUM TO ROTATE THE DRUM ON ITS AXIS, THE SURFACE OF THE DRUM BEING DIVIDED INTO TWO PORTIONS TO FORM A CURVE BETWEEN THE PORTIONS, THE SURFACE OF THE FIRST PORTION HAVING A FIRST LIGHT REFLECTIVITY AND THE SURFACE OF THE SECOND PORTION HAVING A SECOND LIGHT REFLECTIVITY DIFFERENT FROM THE REFLECTIVITY OF THE FIRST PORTION, MEANS FOR ROTATING THE DRUM ON ITS LONGITUDINAL AXIS, A PHOTOELECTRIC DETECTOR HEAD SLIDABLY MOUNTED ON A SECOND AXIS EXTENDING PARALLEL TO SAID DRUM AXIS, A DETECTOR HEAD DRIVE FOR MOVING THE DETECTOR HEAD LONGITUDINALLY ON THE SECOND AXIS, THE PHOTOELECTRIC DETECTOR HEAD INCLUDING A LIGHT SOURCE FOR IMPARTING LIGHT TO THE SURFACE OF THE DRUM AND TWO PHOTOELECTRIC CELLS WITHIN THE DETECTOR HEAD FOR INTERCEPTING THE REFLECTED LIGHT FROM THE DRUM, ONE OF THE PHOTOELECTRIC CELLS BEING POSITIONED TO INTERCEPT LIGHT FROM THE FIRST OF THE PORTIONS ON THE DRUM SURFACE AND THE SECOND OF THE PHOTOELECTRIC CELLS BEING POSITIONED TO INTERCEPT LIGHT FROM THE SECOND OF THE PORTIONS, AND ELECTRICAL MEANS FOR TRANSMITTING FROM THE DETECTOR HEAD A SIGNAL INDICATING THE LIGHT REFLECTED TO EACH OF THE PHOTOELECTRIC CELLS, AND SAID SERVO SYSTEM DRIVE ASSEMBLY COMPRISING A BRIDGE CIRCUIT AND AMPLIFIER FOR RECEIVING THE SIGNAL FROM THE DETECTOR HEAD AND AMPLIFYING AND TRANSMITTING THE SIGNAL, A MOTOR FOR RECEIVING THE SIGNAL AND MOVING THE PUMP ADJUSTMENT MEANS AND DETECTOR HEAD DRIVE RESPONSIVE TO SAID SIGNAL WHEREBY THE DETECTOR IS POSITIONED CONTINUALLY ALONG THE CURVE ON THE DRUM WHILE THE DRUM ROTATES AND THE PUMPS ARE ADJUSTED TO PRODUCE A GRADIENT CORRESPONDING TO THE CURVE ON THE DRUM.