Optical mass gauge sensor having an energy per unit area of illumination detection

• US 6,118,134 A
• Filed: 08/31/1998
• Issued: 09/12/2000
• Est. Priority Date: 09/02/1997
• Status: Expired due to Term

• Current Assignee: Advanced Technologies Group Limited (British American Tobacco PLC)
• Original Assignee: Justak Research & Development, Inc.
• Inventors: Justak, John F.
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US09/143,742
• Time in Patent Office: 743 Days
• Field of Search: 250/577, 250/574, 250/576, 250/904, 250/903, 73/293, 73/290 R, 340/619, 356/436
• US Class Current: 250/577
• CPC Class Codes: G01F 23/292 Light , e.g. infrared or ultraviolet
• CPC Class Codes: G01F 23/2928 using light reflected on the material surface

Abstract

An optical mass gauge sensor is disclosed comprising a vessel having an interior surface which reflects radiant energy at a wavelength at least partially absorbed by a fluid contained within the vessel, an illuminating device for introducing radiant energy at such wavelength into the vessel interior, and, a detector for measuring the energy per unit area of illumination within the vessel created by the radiant energy which is not absorbed by the fluid.

Claims

1. Apparatus for sensing the quantity of a fluid which is capable of at least partially absorbing radiant energy having a particular wavelength, comprising:

a vessel having an interior whose surface reflects radiant energy at said particular wavelength, said interior of said vessel containing said fluid;

an illuminating device for introducing radiant energy at said particular wavelength into said interior of said vessel;

a detector for measuring the energy per unit area of illumination created by the radiant energy within said interior of said vessel which is not absorbed by said fluid.

2. The apparatus of claim 1 in which said illuminating device is a light source mounted to said vessel in a position to introduce radiant energy into said interior of said vessel.

3. The apparatus of claim 2 in which said illuminating device further includes a detector mounted to said vessel in proximity to said light source.

4. The apparatus of claim 1 in which said surface of said interior of said vessel is coated with an optically-diffusing, highly reflective paint.

5. The apparatus of claim 1 in which said detector is a photo-detector.

6. The apparatus of claim 1 in which said fluid is a cryogenic liquid.

8. The apparatus of claim 1 further including a barrier mounted within said interior of said vessel in position to substantially prevent the direct irradiation of said detector with radiant energy emitted from said illuminating device.

7. The apparatus of claim I in which said fluid is liquid natural gas.

9. Apparatus for sensing the quantity of fluid contained within the interior of a vessel whose interior surface substantially reflects radiant energy of a particular wavelength which is at least partially absorbed by the fluid, comprising:

an illuminating device for introducing radiant energy at said particular wavelength into the interior of the vessel;

a detector for measuring the energy per unit area of illumination created by the radiant energy within said interior of said vessel which is not absorbed by said fluid.

10. The apparatus of claim 9 in which said illuminating device is a light source mounted to said vessel in a position to introduce radiant energy into said interior of said vessel.

11. The apparatus of claim 10 in which said illuminating device further includes a detector mounted to said vessel in proximity to said light source without being directly irradiated by said light source.

12. The apparatus of claim 9 in which said detector is a photo-detector.

13. The apparatus of claim 9 in which said fluid is a cryogenic liquid.

14. The apparatus of claim 9 in which said fluid is liquid natural gas.

15. Apparatus for sensing the quantity of at least a first fluid and a second fluid contained within the interior of a vessel whose interior surface substantially reflects radiant energy having a first wavelength which is at least partially absorbed by the first fluid and a second wavelength which is at least partially absorbed by the second fluid, said apparatus comprising:

an illuminating device capable of introducing radiant energy containing the first wavelength and radiant energy containing the second wavelength into the interior of the vessel;

a detector for measuring the energy per unit area of illumination attributable to the radiant energy at each of the first wavelength and said second wavelengths which is not absorbed by the first and second fluids, respectively.

16. The apparatus of claim 15 in which the first fluid is a gas and the second fluid is a liquid.

17. The apparatus of claim 15 in which each of the first and second fluids is a liquid.

18. The apparatus of claim 15 in which each of the first and second fluids is a gas.

19. The method of detecting the quantity of at least one fluid within the interior of a vessel, comprising:

(a) introducing radiant energy into the interior of the vessel having a wavelength which is at least partially absorbed by the fluid therein, and which is at least partially reflected by the interior surface of the vessel;

(b) detecting the radiant energy within the interior of the vessel which is not absorbed by the fluid;

(c) producing a signal having a component which is representative of a measurement of the energy per unit area of illumination created by the radiant energy not absorbed by the fluid.

20. The method of claim 19 in which step (a) comprises directing radiant energy from a light source communicating with the interior of the vessel.

21. The method of claim 19 in which step (b) comprises sensing radiant energy within the interior of the vessel with a photo-detector communicating with the interior of the vessel.

22. The method of claim 19 in which step (a) comprises directing radiant energy into the interior of the vessel having a first wavelength which is at least partially absorbed by a first fluid within the vessel, and directing radiant energy into the interior of the vessel having a second wavelength which is at least partially absorbed by a second fluid within the vessel.