Browsing by Subject "fluidization"

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Access status: Open Access ,
Analiza mechanizmu rozdrabniania ziaren w młynie strumieniowo-fluidyzacyjnym
(2007) Zbroński, Daniel
The basis of comminution mechanism of grains in the fluidized bed opposed jet mills aren't satisfactory explained. It results from the difficulties to determine the influence of all parameters process on the evolution of particle size distribution of milling product. The theoretical analysis and experimental results for grinding tests of limestone on the laboratory fluidized bed opposed jet mill are presented in the paper. The aim of research was to explain the influence of initial graining fed material on the comminution mechanism of grains in the grinding chamber of mill. The analysis showed that comminution in the mill takes place as a result of superficial attrition of grains, dynamic breakage of grains and cleavage of grain agglomerates.
Access status: Open Access ,
Wpływ prędkości obrotowej wirnika klasyfikatora przepływowego na osiągi młyna strumieniowo-fluidyzacyjnego
(2006) Zbroński, Daniel; Górecka-Zbrońska, Aleksandra
The necessity of applying materials with high degree of fineness in the contemporary technologies require used to modern technology in mechanical comminution of different substances, which will assure demanded particle size distribution of grinding product. The scientific performances are mostly aimed at the search for new work conditions of industrial grinding devices, which should guarantee parameters and fineness of grinding products and should decrease energy consuming of grinding and improve environmental protection. All the above seems to be met in the researches of granular materials grinding in the high-energetic fluidized bed. The fluidized jet grinding relies on keeping up a turbulent fluidization in the grinding chamber of mill, which is a result of collisions of air counter-fluxes. They make it possible to obtain high-energetic fluidized bed, which in turn ensures an effective comminution of tested granular material. The state of pulsatory fluidization is created in the certain surroundings of an axial zone of the fluidized bed. The state of fountain fluidization is created in the axial zone of the fluidized bed, which is characterised by carryover of grains in the zone of high velocities in the centre core of grinding chamber, then by gravitational falling of coarse fraction near walls and by carrying away of the small fraction by the flowing gas into the separation system. The theoretical basis and experimental results for the fluidized jet grinding of granular materials are presented in the paper. The researches were performed on a laboratory fluidized bed opposed jet mill. The experiment contained grinding tests of selected narrow size fraction of limestone in turbulent fluidized layer conditions. The aim of researches was to explain the influence of the values of rotational speed of flow classifier rotor on the efficiency of mill and the particle size distribution of grinding product. The determined masses and particle size distribution of grinding products make it possible to estimate the quality and the efficiency of the carried out fluidized jet grinding tests.