Claims
- 1. An apparatus for inspection of a fluid, comprising:
a fluid analysis cell having a cavity therein; an upper and lower light transmitting window enclosing opposite ends of the cavity; a spacer fixedly positioned in said cavity between said upper and lower viewing windows providing a fluid chamber where fluid flows between said windows; a fluid inlet and outlet channel connected in fluid communication with said fluid chamber to enable fluid to flow into and out of said fluid chamber; and, a light transmitting and a light receiving probe positioned in any order above and below the upper and lower viewing windows, wherein the faces of each probe are in axial alignment with each other and are contiguous and flush with the viewing windows and orthogonal to the direction of flow but separated from the flow by the viewing windows, so that transmittance measurements can be taken orthogonal to the direction of flow.
- 2. The apparatus of claim 1 in which a light source and a spectrophotometer are associated with and connected to the probes for directing light to the fluid analysis cell and detecting light therefrom respectively to measure color parameters of the fluid passing through the viewing windows by transmittance.
- 3. The apparatus of claim 2 in which the spectrophotometer is a dual beam spectrophotometer and the light source is a flash lamp.
- 4. The apparatus of claim 3 in which light is transmitted to the fluid analysis cell and received therefrom by means of single-fiber fiber optic cables, terminated in fiber optic probes which interface with the fluid analysis cell viewing windows.
- 5. The apparatus of claim 2 which further includes:
a pressure vessel, in which a fluid sample is placed, and which, by means of pressurization, delivers the sample to the fluid analysis cell; a purged explosion-proof enclosure for containing all electrical/electronic components, as well as the light source for the instrument; and an automatic pneumatically-controlled sample system for delivery of the sample to the fluid analysis chamber.
- 6. The apparatus of claim 4 in which the viewing windows and probe faces are of sapphire glass and the spacer member is of brass.
- 7. The apparatus of claim 2 in which the fluid analysis cell is cylindrical.
- 8. The apparatus of claim 3 in which light is transmitted to the fluid analysis cell and received therefrom by means of fiber optic bundles which interface with the fluid analysis cell viewing windows.
- 9. The apparatus of claim 8 in which one of the transmission fiber optic bundles is interfaced to an integrating sphere having one of its portals contiguous with one of the analysis cell windows, so that diffuse as well as direct transmittance measurements can be made on the fluid sample being analyzed.
- 10. The apparatus of claim 8 in which an additional fiber optic bundle or probe is positioned at an angle other than normal to the fluid sample surface so that reflectance measurements can also be made on the fluid sample being analyzed.
- 11. The apparatus of claim 10 in which one of the analysis cell windows which interfaces with the fluid sample is replaced with a cylinder of a similar material transparent to visible light, such as sapphire, quartz, or the like.
- 12. The apparatus of claim 11 in which the surface of the cylinder distal from the fluid chamber and parallel thereto has one or more facets at an angle to the fluid sample surface, in order to interface with fiber optic bundles or probes, such that said bundles or probes are normal to each facet, for illumination of the sample and/or reception of the light therefrom at an angle other than normal to the surface of the sample, so that reflectance measurements can also be made on the fluid sample being analyzed.
- 13. The apparatus of claim 12 in which the spectrophotometer receives light from more than one of the fiber bundles or probes interfacing with the cylinder facets, and in which the angles of the facets conform with industrial standards such that measurements may be made on fluids, such as paints or pigment dispersions, containing interference materials such as metallic flakes or pearl flakes or the like.
- 14. The apparatus of claim 2 in which the flow of fluid through the fluid analysis chamber is unidirectional and laminar at a uniform shear.
- 15. The apparatus of claim 3 in which the flash lamp is covered by a shroud to provide connections for fiber optic cables or bundles which direct light to the spectrophotometer and fluid analysis cell.
- 16. The apparatus of claim 15 in which the shroud has a shutter assembly attached thereto for blocking light to the fluid analysis cell during photometric calibration of the dual-beam spectrophotometer in order to correct for stray light leakage from the reference side thereof to the sample side thereof during analysis of dark fluid samples.
- 17. A method of measuring a color property of a wet fluid comprising supplying a sample volume of liquid to a transmission cell, allowing the fluid to pass through the cell at a fixed pathlength and zero bypass through two viewing windows enclosing each end of the cell, and measuring the color property of the sample volume by light transmittance through two probes associated with the viewing windows.
- 18. The method of claim 17 in which the sample is flowing through the cell.
- 19. The method of claim 18 in which the flow of the sample is unidirectional and laminar.
- 20. A method for correcting stray light leakage from the reference to the fluid sample channels of a dual-beam spectrophotometer by:
taking a measurement of the light intensities of both spectrophotometer channels with the sample channel blocked before every sample measurement by interjecting a shutter in front of the sample light port on the flash lamp shroud, allowing a “flashing dark” reading to be taken, wherein the sample side of the spectrophotometer detector array is dark except for stray light leakage from the reference side, while the reference side of the array is exposed to full light intensity; ratioing the reference channel intensity of the “flashing dark” reading to the intensity of the reference channel in the actual sample measurement to form a scale factor; applying the scale factor to the “flashing dark” sample channel intensity; and, subtracting the resultant ratioed “flashing dark” sample channel intensity from the sample side of the actual sample measurement, thereby subtracting the stray light leakage, corrected for lamp intensity fluctuations, from the actual sample measurement.
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. §119 from U.S. Provisional Application Ser. No. 60/276,967 (filed Mar. 19, 2001), which is incorporated by reference herein for all purposes as if fully set forth.
Provisional Applications (1)
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Number |
Date |
Country |
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60276967 |
Mar 2001 |
US |