E.i. Dupont De Nemours and Company

Thomas W Simpson, Iii

Ken Stephen Schermacher

Anthony Joseph Martino

Jeff B Alspach

Matthew Paul Reinhardt

Robert Vincent Canning, Jr

Barry Rubin

Jason R Juhasz

William E Wolf

Mark E Lewittes

Michael J Merrill

Scott Richard Mehr

Eugene Francis Palecki

Robert H Livermore

Douglas Ray Stilwell

David D Dreyfuss

John J Majeski

A system utilizing the flow cell of the present invention includes a reflectance mode spectrophotometer positioned with respect to the flow cell or a probe. Either the flow cell or the probe has a thin partition mounted in spaced relationship with respect to a transparent window. The partition has a predetermined index of refraction and has a thickness dimension that is less than that of the window. The spacing between the partition and the window is such that evanescent coupling of radiation reflected from the liquid into the material of the window is prevented. The spectrophotometer directs interrogating radiation toward a liquid flowing through the sample chamber and responds to interrogating radiation reflected from the liquid to produce an electrical signal representative of a color property thereof.

System for measuring a color property of a liquid

An automated computer-controlled method and apparatus for measuring the quality or fineness of a pigment dispersion sample, comprising placing the pigment dispersion at the deep end of the tapered path of a Hegman gage block, placing the Hegman gage block in a holder in a motorized drawdown device that draws the scraper along the length of the tapered path at an angle and to at a contact pressure and at a controlled rate, thereby creating a tapered film sample of paint whose thickness tapers from a maximum thickness of 100 micrometers to a minimum thickness of zero. An illuminator assembly illuminates the sample with a substantially collimated light source at an intensity level and the light reflected from the sample is collected by a lens onto a photodetector array in a digital camera. After a time interval the camera acquires an image of the sample. The image is digitized and stored in a memory in the computer and then a portion of the image within a region of interest corresponding to the sample in the tapered path is analyzed to detect and count pigment agglomerates that protrude above the surface of the sample.

Method and apparatus for quantifying pigment dispersion quality by paint drawdown

A flow cell for measuring the color properties of a liquid flowing therethrough using interrogating radiation at a predetermined wavelength has a thin partition mounted in spaced relationship between both a window and a base of the cell. The partition and the window define an air cavity therebetween. The spacing between the partition and the window is such that evanescent coupling of radiation reflected from the liquid into the material of the window is prevented. The cell has a pressurized fluid inflow channel and a pressurized fluid outflow channel formed therein. Each of the inflow and outflow channels communicates with the air cavity. The inflow and outflow channels are sized to pass a pressurized fluid, such as pressurized air, through the air cavity such that, in use, the spaced relationship between the partition and the window is maintained by pressurized fluid in the air cavity. The pressure of the pressurized fluid in the air cavity is determined in accordance with the pressure of the liquid flowing through the cell.

Liquid measurement cell having a pressurized air cavity therein

A flow cell for measuring the color properties of a liquid flowing through the flow cell using interrogating radiation at a predetermined wavelength has a thin partition mounted in spaced relationship between both a window and a base of the cell. The partition has a predetermined index of refraction and has a thickness dimension that is less than that of the window. The spacing between the partition and the window is such that evanescent coupling of radiation reflected from the liquid into the material of the window is prevented. Typically, this spacing is a distance not less than three (3) times the predetermined maximum wavelength in the wavelength range of interrogating radiation. A plurality of spacer elements may be disposed in the air cavity to maintain the spaced relationship between the partition and the window. The flow cell has a liquid supply passage and a liquid removal passage formed therein. The liquid supply passage, the sample chamber and the liquid removal passage cooperate to define a liquid flow path through the flow cell. The liquid supply passage, the sample chamber and the liquid removal passage are configured such that any cross section taken in a plane substantially perpendicular to the liquid flow path at any location therealong exhibits substantially the same cross-sectional area.

Liquid measurement cell having a transparent partition therein

An improved image analysis method to quantify uniformity of visual appearance of planar objects. The measurements are substantially independent of both the image shading and the overall lightness differences among the objects.

Method of quantifying visual uniformity of planar objects

An apparatus for optically detecting light-absorbing contamination in at least one particle of low optical-loss material comprises an optical integrating chamber for containing the particles. A laser for emitting a laser beam to illuminate the particles is mounted in the plane of rotation of a rotating mirror such that the laser beam scans in a fan scan. A scanning assembly is mounted in optical alignment with the laser for reflecting the laser beam and for causing the laser beam to scan the particles in the optical integrating chamber. A focusing assembly is mounted in optical alignment with the laser for focusing the scanning laser beam onto the particles in the chamber, the focusing assembly operating in conjunction with the scanning assembly so that light from the laser beam is reflected from the particles and is repeatedly scattered onto the interior walls of the integrating chamber. A light sensing assembly is mounted on the integrating chamber for receiving the repeatedly scattered light from the interior walls of the integrating chamber and for generating a signal indicative of the intensity of the repeatedly scattered light. A decrease in the intensity of the repeatedly scattered light is a function of the presence of light-absorbing contamination in the material.

Apparatus for optically detecting contamination in particles of low

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Boothwyn, PA, United States of America

Thomas W Simpson, Iii