Fiber optic detection system

• US 5,362,971 A
• Filed: 03/10/1993
• Issued: 11/08/1994
• Est. Priority Date: 03/10/1993
• Status: Expired due to Fees

• Current Assignee: Terrascope Systems, Inc.
• Original Assignee: Terrascope Systems, Inc.
• Inventors: Ivashin, Victor, McMahon, Robert L., McCullough, Robert B.
• Primary Examiner(s): Nelms, David C.
• Application Number:
  US08/029,017
• Time in Patent Office: 608 Days
• Field of Search: 250/577, 250/904, 250/227.25, 356/133
• US Class Current: 250/577
• CPC Class Codes: G01N 21/431 Dip refractometers, e.g. using optical fibres
• CPC Class Codes: Y10S 250/904 with single light guide element to guide light in a continuous path

Abstract

A fiber optic detection system in which a single optic fiber has a U-shaped configuration. A source of light is disposed at one upper free end of the optic fiber and a light detector is disposed at the other upper free end of the optic fiber. At the bottom of the optic fiber is a light variable loop adapted to be disposed in various media, such as liquids, fluids and air. The light from the source of light is conducted from the source of light through the optic fiber and to the light detector. The quantum of light lost as the light travels through the light variable loop will depend on the medium or the concentration of the medium in which the light variable loop is disposed. The light detector detects the light advancing thereto to produce a signal representative of the medium or the concentration of the medium in which the light variable loop is disposed. An electronic circuit with a microprocessor is responsive to the signal produced by the light detector for determining the medium or the concentration of the medium in which the light variable loop is disposed.

Claims

1. A fiber optic detecting system comprising:

(a) an optic fiber element having intermediate the ends thereof a continuous light variable section;

(b) a source of light disposed at one end of said optic fiber element for providing light for conduction through said optic fiber element; and

(c) a light detector disposed at the other end of said optic fiber element for detecting the quantum of light passing through said light variable section and producing an output signal representative of the quantum of light detected;

(d) said light variable section being adapted to be disposed in a medium and the quantum of light travelling from said light variable section to said light detector being dependent on the light absorption characteristics of the medium in which said light variable section is disposed, said light detector producing a signal representative of the medium in which said light variable section is disposed; and

(e) an electronic circuit having a microcomputer connected to said light detector and responsive to the output signal of said light detector for measuring the quantum of light resulting from the light absorption characteristics of the medium in which said light variable section is disposed for determining the medium in which said light variable section is disposed.

2. A fiber optic detection system as claimed in claim 1 in which said optic fiber element is a single optic fiber element.

3. A fiber optic detection system as claimed in claim 1 wherein said light variable section is a light variable loop.

4. A fiber optic detection system as claimed in claim 2 wherein said light variable section has the configuration of a light variable loop.

5. A fiber optic detection system as claimed in claim 3 wherein said optic fiber element has a U-shaped configuration with downwardly extending legs, said light variable loop of said optic fiber element being adjoined to the lower ends of said legs.

6. A fiber optic detection system as claimed in claim 4 wherein said optic fiber element has a generally U-shaped configuration with downwardly extending legs, said light variable loop of said optic fiber element being adjoined to the lower ends of said legs.

7. A fiber optic detection system as claimed in claim 5 wherein said light variable loop has an arcuate section with radii of predetermined dimension.

8. A fiber optic detection system as claimed in claim 6 wherein said light variable loop has an arcuate section with radii of predetermined dimension.

9. A fiber optic detection system as claimed in claim 7 wherein said optic fiber element comprises opaque means surrounding said legs.

10. A fiber optic detection system as claimed in claim 8 wherein said optic fiber element comprises opaque means surrounding said legs.

11. A fiber optic detection system as claimed in claim 1 wherein said microcomputer is connected to said source of light and said light detector for regulating the intensity of light emitted by said source of light and for measuring the quantum of light detected by said light detector for determining the medium in which said light variable section is disposed.

12. A fiber optic detection system as claimed in claim 11 wherein said electronic circuit comprises a digital-to-analog converter interconnecting said microcomputer and said source of light to adjust the intensity of light emitted by said source of light and an analog-to-digital converter interconnecting said light detector and said microcomputer for measuring the quantum of light detected by said light detector, said microcomputer in responding to the signal representing the quantum of light from said analog-to-digital converter determines the medium in which said light variable section is disposed.

13. A fiber optic detection system as claimed in claim 12 wherein said electronic circuit comprises memory means connected to said digital-to-analog converter and said analog-to-digital converter for recording the input signals to said digital-to-analog converter adjusting the light intensity of said source of light and for recording the output signal of said analog-to-digital converter to measure the quantum of light detected by said light detector.

14. A fiber optic detection system as claimed in claim 3 wherein said microcomputer is connected to said light detector for detecting the quantum of light escaping through said light variable loop to determine the medium in which said light variable loop is disposed.

15. A fiber optic detection system as claimed in claim 3 wherein said microcomputer is connected to said light detector for detecting the quantum of light escaping through said light variable loop to determine the medium in which said light variable loop is disposed, the loss of light being commensurate with the light refraction characteristic of said medium.

16. A fiber optic detection system as claimed in claim 3 wherein said light variable section has a curved configuration and the light escaping through said light variable loop is related to the curvature of said light variable section and the light refraction characteristic of the medium in which said light variable section is disposed.

17. A fiber optic detection system as claimed in claim 4 wherein said light variable section has a curved configuration and the light escaping through said light variable loop is related to the curvature of said light variable section and the light refraction characteristic of the medium in which said light variable section is disposed.

18. A fiber optic detection system as claimed in claim 14 wherein said detection of the quantum of light escaping from said variable loop enables said microcomputer to measure the index of refraction of the medium in which said light variable loop is disposed.

19. A fiber optic detection as claimed in claim 15 wherein said detection of the quantum of light escaping from said variable loop enables said microcomputer to measure the index of refraction of the medium in which said light variable loop is disposed.

20. A fiber optic detection system as claimed in claim 3 and comprising a protective cover in which said light variable loop is disposed for protecting said light vaiable loop against marring, said protective cover being formed with openings therein to dispose said light variable loop in the medium.

21. A fiber optic detection system as claimed in claim 4 and comprising a protective cover in which said light variable loop is disposed for protecting said light variable loop against marring, said protective cover being formed with openings therein to dispose said light variable loop in the medium.

22. A fiber optic detection system as claimed in claim 1 wherein said microcomputer is connected to said source of light for turning said source of light alternately on and off in predetermined time intervals.

23. A fiber optic detection system as claimed in claim 1 and comprising cladding surrounding said light variable section.

24. A fiber optic detection system as claimed in claim 1 wherein said optic fiber element has downwardly extending legs and said light variable loop of said optic fiber element being adjoined to the lower ends of said legs, said fiber optic detection system comprising cladding disposed around said legs and said light variable section, said fiber optic detection system comprising a protective cover surrounding the cladding disposed around said legs.