Showing papers in "Powder Technology in 1969"

TL;DR: The Hausner Ratio between the tap density and apparent density of a powder mass is termed as the hausner ratio as mentioned in this paper, which measures the friction condition in a moving powder mass.

TL;DR: In this paper, the authors used a penetration porosimeter to determine the void spaces and pores in a porous material by use of a penetration-porosimeter and other characteristics, such as the particle size distribution and specific surface.

TL;DR: A study of powder segregation during die filling with two-component mixes of Pb particles has shown that: (1) Segregation occurs by fines filtering down through the moving powder mass as mentioned in this paper.

TL;DR: In this paper, a qualitative evaluation of the influence of a number of operating parameters has been made, the deformation of the free surface making this readily observable, including the blade height and immersion, and effects, the presence of a floor, blade roughness, the inclination or rake angle of the blade and blade velocity.

TL;DR: The effect of changes in several grinding variables on the flow characteristics of liquid and solids through a small continuous wet ball mill has been studied in this article, and the results show that the general form of the distribution of residence time function was not significantly altered by changes in the grinding variables studied but that large changes in mean residence time could occur due to induced changes in hold-up weight.

TL;DR: In this article, the effect of air injection on the discharge of particles from a bunker has been studied on the basis of the mechanical energy balance and empirical correlation of solids mass flow has been derived.

TL;DR: In this paper, simultaneous measurements of the adhesive force and double electric charge of particles after their removal from a metal surface were made, and a calculation was made of the surface density of charge for the polyvinyl chloride particle-steel system.

TL;DR: In this article, the packing of spheres has been studied experimentally and the density of the random packing was 61% which is that reported in the literature by several investigators using similar shaking.

TL;DR: In this article, the displacement of tracer, particles in a granular material over a long horizontal blade that is moving relative to the bed, was studied in dimensionless form.

TL;DR: In this paper, the velocity field in a flat-bottom bin and a vee-shaped bin fitted with slot outlets was determined by photographically tracking a sufficient number of particles and the magnitude and direction of the velocity vector could be determined everywhere.

TL;DR: In this article, conditions for spontaneous wetting have been derived and experiments have been presented which substantiate the given theory in a qualitative manner, and it has been shown that if air is entrapped in the aggregates, the air can only escape from the aggregate when the capillaries differ in size and the larger openings are situated at the outer surface of the aggregate.

TL;DR: In this paper, a new method is described for measuring the mass flow of powder in a pneumatic conveyor without obstructing the flow of the material or using moving parts.

TL;DR: In this paper, the results of 239 experimental runs on grinding calcite of particle size range 0.15-1.70 mm in an experimental jet mill of 20 mm diameter, using feed rates of 5-150 g/min and air pressure of 3-6 kg/cm 2 G are reported.

TL;DR: In this article, the properties of non-random binary mixtures, that is mixtures in which the probability of finding a particle of one component is not constant throughout the mixture, are examined theoretically.

TL;DR: In this article, the effect of changes in the hold-up weight of calcite environment in a small continuous wet ball mill on the grinding behaviour of quartz tracer solids has been studied.

TL;DR: The fluid energy mill provides a quick and effectice means of reducing powders to an average particle size of as discussed by the authors, which can be used to reduce the energy consumption of the mill.

TL;DR: In this article, a quantitative theory is developed to describe mixing in particulate systems in which one component is present only as a trace quantity, and theoretical expressions are derived to predict the rates of mixing of essentially identical components both as spherical or as angular particles.

TL;DR: In this article, an investigation of the hydrodynamics of a suspension ((10 μ magnesia in air) over the inlet of a channel formed by two flat plates was made for various flow velocities, plate gap widths, and mass flow ratios of solids to air.

TL;DR: The relationship between extinction coefficient K and particle size has been derived theoretically for plane, parallel, monochromatic radiation and small angle of acceptance for spheres and infinitely long cylinders as mentioned in this paper.

TL;DR: In this paper, it is shown that an assumption that the granular material fails in a logarithmic spiral surface leads to the prediction of forces close to the experimental values, however, because solutions are not always unique and because of doubt as to boundary conditions at the blade face.

TL;DR: In this article, a study of the behavior of fine particles during their separation from coarse oversize particles in a batch sieving process was made, and the experimental results were interpreted in terms of a theoretical model, which allowed for the effects of three possible rate controlling mechanisms, namely segregation, dispersion and resistance to flow through the sieve apertures, on the rate of sieving.

TL;DR: In this article, two statistical methods of particle size distribution measurement were studied and compared and it was found that the Scheil method appeared to be the more stable one and it needed only about 10 intercepts (each intercept resulting in a circle) per sphere, on the average, to yield satisfactory results.

TL;DR: In this paper, the effect of shape on sieving time has been investigated, and it was concluded that Sieving time depends on the number of points on the particle, rather than on flatness or elongation.

TL;DR: In this article, an experimental study into the effects of varying particle characteristics on maximum and minimum bulk densities of dry quartz powders was presented, and an empirical formula for the maximum density of such powders is proposed.

TL;DR: The principle and the requirements of counterflow equilibrium and transverse flow classification is discussed and two new classifiers based on the conclusions drawn are described.

TL;DR: In this article, the industrial need for solids flow instrumentation is discussed and current industrial methods of solidsflow detection and measurement are reviewed, and it is concluded that a range of satisfactory instruments are often available for systems where the solid material is conveyed on a belt, or is falling freely under gravity.

TL;DR: In this article, a theoretical equation for the lateral dispersion coefficient of gas in vigorously bubbling fluidized beds was derived on the basis of the bubbling bed model of Kunii and Levenspiel.