IN SITU FLUOROMETER USING A SYNCHRONOUS DETECTOR

• US 3,649,833 A
• Filed: 04/16/1970
• Issued: 03/14/1972
• Est. Priority Date: 04/16/1970
• Status: Expired due to Term

• Current Assignee: William Benjamin Leaf
• Original Assignee: William Benjamin Leaf
• Inventors: Leaf, William Benjamin
• Primary Examiner(s): Lawrence, James W.
• Assistant Examiner(s): Frome, Morton J.
• Application Number:
  US05/134,781
• Time in Patent Office: 698 Days
• Field of Search: 250/71R,71G,43.5R,43.5MR,71.5,833H,836FT,835A 350/96R 356/246
• US Class Current: 250/432.00R
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 2201/0218 Submersible, submarine

Abstract

Disclosed herein is a self-contained submersible fluorometer designed for the continuous in situ recording of concentrations of materials in an aqueous environment, said materials being stimulated to fluoresce when excited by light of proper wavelengths.

Claims

1. In an apparatus for measuring the light generated by fluorescing materials suspended in a liquid medium and including a dual light path optical bridge, a source of light for illuminating both paths, a transparent sample chamber disposed in one path for carrying the liquid medium, means for restricting the light entering the sample chamber to a selected wavelength, means for filtering the light leaving the sample chamber to a selected wavelength, servo means disposed in the other path for varying the optical transmissivity thereof, a photodetector for sensing the light leaving both paths, a light chopper disposed between the ends of both paths and the photodetector to alternately direct light from both paths to said photodetector, and electrical circuit means responsive to the photodetector output for controlling the servo means, the improvement characterized by:

a. the light chopper comprising a motoR driven rotating shutter, b. the electrical circuit means comprising a synchronous detector, and c. a reference signal photodetector positioned such that received light is chopped by said rotating shutter for supplying a synchronizing signal for providing the phase reference to the synchronous detector.

2. The apparatus of claim 1 wherein said servo means includes a servo motor coupled to said electrical circuit means and a neutral density wedge filter coupled to said servo motor for rotation therewith to vary the illumination in the other light path.

3. The apparatus of claim 2 wherein said servo means further includes a position potentiometer coupled to said neutral density wedge filter, the output of said potentiometer being proportional to the position of said wedge filter.

4. The apparatus of claim 3 wherein said other light path is defined by a fiber optic light conducting tube.