Showing papers in "Powder Technology in 1968"

TL;DR: In this paper, a modele geometrique simple de l'excedent de porosite observe experimentalement dans la premiere couche de grains spheriques au contact d'une paroi plane and lisse.

TL;DR: In this article, an annular shear cell was developed for measuring the strength characteristics of granular materials as part of a project whose aim is to establish a basis for the design of bunkers to handle these materials.

TL;DR: In this paper, the authors discuss the methods of describing, specifying and testing mixtures, and propose that mixers can be classified as either segregating or non-segregating, and a guide to the selection of the mixer for a particular duty is provided.

TL;DR: In this paper, it was shown that the shear index n in the yield locus equation ( τ C n = σ T + 1 where τ = shear stress T = tensile strength σ = normal stress C = cohesion can be correlated with the volume surface mean diameter in microns by means of the general equation n = 1 + B (d) X where B = constant d = volume/surface mean diameter while the tensile weight T is correlated by the equation T = A( ϱ ϱ s )m where A and m = constants ϱ

TL;DR: In this article, general equations in terms of mass balances were developed to relate the particle size distributions and flow rates of feed and outflow streams in fluidized beds, taking into account the size distribution of feed solids, arbitrary particle growth or shrinkage within the bed, and the effect of elutriation of fines on the properties of both outflow and carryover streams.

TL;DR: In this article, the influence of changes in ball diameter on the grinding behavior of trace quantities of quartz within an environment of calcite in a small continuous wet ball mill has been studied.

TL;DR: In this article, a conical insert is proposed to reduce the tendency of a funnel flow to form stable arches or pipes. But the insert is not suitable for large-scale installations, and although it may be desirable to replace them by mass flow hoppers, this may not be economic.

TL;DR: In this paper, the settling behavior of unflocculated suspensions at high concentrations is discussed, and it is shown experimentally that particle segregation occurs up to a limiting concentration in excess of 30% by volume.

TL;DR: In this paper, the random path model of screening for the various screen types is shown to explain several of the empirical screening relationships and the mechanics of motion of a particle on a screen surface are discussed.

TL;DR: In this paper, it was observed that particulate solids assume a circulatory motion in a two-dimensional hopper-shaped vessel when the vessel is subjected to vertical sinusoidal vibration.

TL;DR: In this paper, an etude theorique basee on un modele decrivant la perturbation apportee par un obstacle dans un lit de spheres, l'exploitation de resultats experimentaux de la litterature and d'experiences effectuees sur un pavable de spheres dans a plan, permettent de proposer une expression de la coordinance de contact, devrait se reveler utile dans le cas de melanges binaires de spheres.

TL;DR: In this article, the expansion of freely bubbling gas fluidized beds has been investigated experimentally in a 12-in. diameter bed and the influence of bed depth, gas velocity, particle size and particle-size distribution has been studied.

TL;DR: In this paper, the authors used a vibrating die to fill a 10-35 mesh lead mixture with a fine (80-325 mesh) die and found that the coarse component tends to locate in the bottom zone of the die during vibratory die filling.

TL;DR: In this article, the effect of variables on the rate and degree of segregation in geometrically reduced model bins is investigated and the scale-up of these results to storage systems of industrial size is discussed.

TL;DR: In this article, a semi-empirical formula for the discharge rate of particles from a vibrating hopper is derived with the aid of a model combining a fluid analogy and the motion of a particle on vibrating plate.

TL;DR: In this article, it is suggested that the effects of particle shape upon the time to reach peak blinding are directly related to the frictional condition in the moving powder mass, characterised by the Hausner ratio tap density/apparent density.

TL;DR: In the electrode paste plant of Elektrokemisk A/S in Norway, fine anthracite used to flood uncontrollably out of a funnel-flow bin over a belt feeder as mentioned in this paper.

TL;DR: In this article, a radio pill was used to measure the mean pressure at various points in the material during discharge and the stress distributions from the results were compared with those predicted by the Jenike-Johanson and Walker theories.

TL;DR: In this paper, a mathematical relationship between Martin's and Feret's statistical diameters for elliptical-shaped particle profiles and the major and minor axes of the ellipse has been investigated.

TL;DR: A critical survey of the different models proposed for solids transport in gas-fluidized beds is given in this paper, where it is shown that many of the models can fit the residence time distribution curve (the F t -t curve) fairly well despite the fact that the physical behaviour of the bed is not recognized in these models.

TL;DR: It is shown that considerable semantic confusion concerning “random chord” populations exists in the literature and standard definitions are proposed and techniques for improving the efficiency of statistical methods using antithetic variable principles and averaging techniques in which errors cancel instead of accumulating are suggested.

TL;DR: In this paper, the steady-state flow of sand in a flat-bottomed cylindrical vessel with a central opening and a height-to-diameter ratio greater than 5 is investigated by a method which consists of fixing the granular mass with paraffin.

TL;DR: In this paper, the effect on discharge rate of the hopper shape, and the size and form of the outlet and properties of the bulk material (mean particle size, shape, moisture content, internal friction and specific gravity) have been investigated.

TL;DR: In this paper, it was shown that small but significant differences occurred using different volumes of powder and different types of powder, although the effect due to different powder may well be a manifestation of the former effect since the packing arrangement (porosity) of the plug was not known.

TL;DR: In this article, the trajectories of particles with diameters from one to 50 microns were examined both theoretically and experimentally for the non-steady, two-dimensional motion of particles in viscous fluids.

TL;DR: In this article, a hematite-quartz ore was ground in a rod mill and the size analysis and surface area of the products were determined, and the fineness of the ground product decreased as the pH of the pulp increased.

TL;DR: In this article, a mixing model for particles flowing through a vibrated two-dimensional hopper-shaped vessel is proposed, based on the observed flow pattern, and a transfer function is used for the expression of this model.

TL;DR: Radiant heat transfer to clouds composed of gas suspended solid particles of known concentration, relating radiant energy absorption to particle size was discussed in this paper, where it was shown that the size of the particles is correlated with the amount of radiant energy absorbed.