Parameters for assessing fiber fractionation and their application to screen rotor effects.APPLICATION: TMP TMP (thymidine monophosphate): see thymine. mills can use the results of this study to enhance the level of fractionation fractionation /frac·tion·a·tion/ (frak?shun-a´shun) 1. in radiology, division of the total dose of radiation into small doses administered at intervals. 2. that can be obtained by their screening systems. This study also provides insights into some inherent limitations of fractionation in regard to reject thickening thick·en·ing n. 1. The act or process of making or becoming thick. 2. Material used to thicken: stir in a thickening of flour and water. 3. A thickened part. . Fiber fractionation is a process that segregates fibers into two or more streams based on differences in their physical properties. Fibers can thus be directed to the product or process for which they are best suited. Pulp screens are commonly used for fractionation, and the two essential components of the screen are the rotor and cylinder. The present study was conducted to determine the combination of rotor speed, rotor type, hole size, and passing velocity that provides optimal fractionation. Tests were conducted using industrial pulp screens and results were analyzed in terms of "passage ratio" and selected fractionation constants. Rotor variables had a significant effect on fractionation, but the effects were not as great as from changes in hole size. Passage ratio increased with rotor speed in some cases and decreased in other cases. The nature of the relationship depended on passing velocity, rotor type, and aperture An orifice. It often refers to an opening in which light is allowed to pass in optical systems such as cameras and lasers. See f-stop and numerical aperture. size. The highest level of fractionation occurred with the smallest aperture, lowest passing velocity, and lowest value of passage ratio. In certain cases, a higher rotor speed could offset the negative influence of a higher passing velocity on fractionation. The tie between fractionation and reject thickening was also examined in this study. Increased fractionation was coupled to increased reject thickening (i.e. lower passage ratio) and the relationship was independent of rotor speed, rotor type and passing velocity. Thus, the practical limits to reject consistency in a pulp screen impose limits to the obtainable degree of fractionation. Further increases in fractionation would seem to require a fundamental change that uncouples fractionation and thickening. View this paper online at http://www.tappi.org/index.asp?pid=28863 Robert Gooding and Norman Roberts were with the Pulp and Paper Research Institute of Canada, 3800 Wesbrook Mall, Vancouver, British Columbia British Columbia, province (2001 pop. 3,907,738), 366,255 sq mi (948,600 sq km), including 6,976 sq mi (18,068 sq km) of water surface, W Canada. Geography , Canada V6T 2C1 at the time of this work. Gooding is now with Advanced Fibre Technologies, 5890 Monkland Avenue, Suite 400, Montreal, QC H4A 1G2, James Olson James Olson may refer to:
Vancouver The Vancouver campus is located at Point Grey, a twenty-minute drive from downtown Vancouver. It is near several beaches and has views of the North Shore mountains. The 7. , 2324 Main Mall The Main Mall was an outdoor pedestrian shopping plaza in downtown Poughkeepsie, New York, which was in existence from 1973 until 2001. A urban renewal project designed with the intention of stopping the decline of the central business district of downtown Poughkeepsie, the mall , Vancouver, British Columbia, Canada V6T 1Z4. Email Dlson at olson@mech.ubc.ca. |
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