Method and apparatus for eliminating air during fluid turbidity measurement

Claim 1

In a turbidimeter for sensing the turbidity of a continuously flowing fluid sample including a container for supporting a vertical column of fluid to be tested, means defining a drain opening in said container for establishing an upper surface on said fluid column whereby the fluid may drain from the column at the level of said upper surface, inlet means for transmitting a continuous flow of fluid to said column, a light source fixed relative to said container for directing a beam of light down into said fluid column, means including photoelectric cells surrounding said light beam and being disposed facing the beam passing through the fluid column to define a measuring zone, the electrical output of said cells being dependent upon the amount of light energy from said light beam that is reflected toward the photoelectric cells by particles suspended in said fluid, the improvement comprising, an air trap zone disposed between the inner wall of the container and the central portion of the fluid column through which said light beam passes, said air trap zone being in communication with the inlet means transmitting said fluid flow to the column, vent means connecting said air trap zone to said drain outlet, and said air trap means extending downwardly a substantial distance along the length of said container so that fluid flowing through said air trap zone is present a sufficient length of time to eliminate air and reach a quiescent state prior to flowing up through the central column to the measuring zone and departure of said fluid through said drain.

Claim 6

A method of sensing the turbidity of a fluid sample in a turbidimeter having a chamber including inlet and outlet means and a sensing zone including means for measuring light energy reflected from a beam of light passed through a fluid column in said chamber comprising the steps of, (a) flowing the fluid continuously to the turbidimeter inlet at a predetermined rate, (b) directing said fluid flow through an air trap zone isolated from said sensing zone, (c) maintaining said fluid in the air trap zone by means of said flow rate for a sufficient time period to remove air bubbles present in said fluid and (d) directing said fluid free of entrained air through an elongated path sufficient to reach a quiescent flow of said fluid to the sensing zone for the turbidity test prior to exiting of said fluid through the outlet.

Claim 7

A method of sensing the turbidity of a fluid sample in a turbidimeter having a chamber including inlet and outlet means and a sensing zone including means for measuring light energy reflected from a beam of light passed through a fluid column in said chamber comprising the steps of, (a) flowing the fluid continuously to the turbidimeter inlet at a predetermined rate, (b) directing said fluid flow through an air trap zone isolated from said sensing zone, (c) maintaining said fluid in the air trap zone by means of said flow rate for a sufficient time period to remove air bubbles present in said fluid and (d) directing said fluid free of entrained air through an elongated path sufficient to reach a quiescent flow of said fluid to the sensing zone for the turbidity test prior to exiting of said fluid through the outlet.