The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 05, 1991
Filed:
Nov. 01, 1990
Stuart Farquharson, Freeport, TX (US);
Peter T Keillor, III, West Columbia, TX (US);
The Dow Company, Midland, MI (US);
Abstract
A method for the on-line determination of the residence time distribution of a polymer extruder by injecting a quantity of dye, such as Mobay Red 5B, into the feed throat of the extruder and then photometrically monitoring the polymer flowing from the extruder for the dye. The advance of the present invention is to direct a single beam of polychromatic light through the polymer flowing from the extruder, e.g., by using a quartz-halogen light source and an optical fiber, and then to split this single beam of light that has passed through the polymer into two beams, e.g., by the use of a bifurcated optical fiber, each of which resulting beams are then passed through a separate filter to a separate photodetector. The wavelength of maximum transmission of one of the filters is selected to be near the wavelength of maximum light absorption of the dye so that the signal from the photodetector associated with this filter is a function of the concentration of the dye in the polymer flowing from the extruder. The wavelength of maximum transmission of the other filter is selected to be near the wavelength of minimum light adsorption of the dye and the polymer so that the signal from the photodetector associated with this filter is a function of the background light absorption of the polymer flowing from the extruder. The noise level of the dye concentration signal can be a problem due to bubbles and inclusions in the polymer flowing from the extruder and this noise level is substantially reduced by correcting the dye concentration signal with the background signal.