Extended range turbidimeter

Claim 1

A TURBIDIMETER COMPRISING, IN COMBINATION, A LAMP, A LENS AND SHUTTER POSITIONED ADJACENT SAID LAMP FOR DIRECTING A NARROW BEAM OF LIGHT AT A SHARPLY ACUTE ANGLE SUBSTANTIALLY LESS THAN 45* WITH RESPECT TO THE HORIZONTAL, AN ELONGATED FLUID SAMPLE CONTAINER, SAID CONTAINER HAVING AN OPEN TOP WHOSE EDGE PORTIONS LIE IN A SUBSTANTIALLY HORIZONTAL PLANE, SAID MEANS INCLUDING AN INLET OPENING IN SAID CONTAINER FOR INTRODUCING FLUID BELOW SAID OPEN TOP SO THAT FLUID WILL SPILL OVER SAID EDGE PORTIONS AND MAINTAIN A FLOWING SMOOTH UPPER FLUID SURFACE IN THE CONTAINER, A TROUGH FOR COLLECTING AND DISCHARGING FLUID SPILLED OVER SAID EDGE PORTIONS, SAID CONTAINER BEING ANGLED SO THAT SAID LIGHT BEAM STRIKES SAID FLUID SURFACE AND THE ELONGATED DIMENSION OF THE CONTAINER PARALLELS THE PORTION OF SAID BEAM THAT IS REFRACTED INTO THE FLUID, AND A LIGHT SENSITIVE DEVICE POSITIONED CLOSELY ABOVE THE AREA WHERE SAID BEAM STRIKES SAID FLUID AND JUST OUT OF SAID LIGHT BEAM FOR DETECTING LIGHT SCATTERED UPWARDLY FROM PARTICLES AT OR JUST BENEATH SAID SURFACE.