RU2119393C1 - Method for separating lumpy material by shape - Google Patents

Abstract

FIELD: mining, construction and other branches of industry, in particular, minerals concentration, production of chippings etc. SUBSTANCE: method involves feeding lumpy material onto inclined surface; providing collision of lumpy material against rotating cylindrical surface upon sliding of lumpy material from inclined surface. EFFECT: wider operational capabilities and increased efficiency in separating lumps of slab and cubical shape. 2 dwg

Description

 The invention relates to processes for separating particles by shape and can be used in mineral processing, the construction industry in the production of crushed stone, and other industries.

 Known methods for separating the material according to the shape of the pieces by feeding it to the grate with a pointed shape of grates or to a sieve with slit-like openings, allowing to separate from each other, for example, flat and rounded grains [1].

 The disadvantage of these methods is the low separation efficiency due to the inevitable spread of pieces by size, as well as due to the rapid clogging of cracks.

 A known method of separation in shape and friction of particles by feeding them to an inclined plane with subsequent sliding on it of flat particles and rolling round [2].

 The advantage of the method is the simplicity of its implementation, the disadvantage is the low separation efficiency.

 The proposed method for separating pieces of material in shape is aimed at increasing the efficiency of separation of pieces of flaky and cuboid shapes.

 This is achieved according to the invention due to the fact that a significant difference in the dynamic characteristics of pieces of flaky and cuboid shapes is used, which manifests itself when they suddenly come into contact with an obstacle.

где
V - величина скорости куска при сходе с наклонной плоскости;
V_с - окружная скорость вращения цилиндрической поверхности;
R - коэффициент восстановления нормальной составляющей скорости при ударе (0<R<1);
U - угол наклона плоскости к горизонту,

γ - - угол, характеризующий форму частицы и равный

где a и b - длины наименьшего и наибольшего ребер.As an obstacle, it is proposed to use a rotating cylindrical surface [1], on which pieces of material fall directly after they slip along an inclined plane [2] (Fig. 1). When sliding along an inclined plane, the pieces are oriented so that their smallest side is directed perpendicular to the slip plane. Therefore, when striking a cylindrical barrier, the pieces have a certain orientation of their center of mass relative to the point of contact with the barrier. This orientation depends on the shape of the piece and determines its dynamic characteristics, which, in turn, determine the speed of the center of mass and the angular velocity of the piece after impact. The calculation of the collision process based on Newton’s hypothesis about a change in the normal component of the velocity of the contact point upon impact, as well as the fundamental laws of change in the momentum and moment of momentum, leads to the following formula for the absolute absolute velocity V of the center of mass (point O) of the piece in the horizontal direction (Fig. . 2):

Where
V is the value of the speed of the piece when leaving the inclined plane;
V _with - peripheral speed of rotation of the cylindrical surface;
R is the recovery coefficient of the normal component of the velocity upon impact (0 <R <1);
U is the angle of inclination of the plane to the horizon,

γ - is the angle characterizing the particle shape and is equal to

where a and b are the lengths of the smallest and largest edges.

Таким образом, мы обеспечим движением ледащных и кубовидных кусков в противоположные стороны от точки удара. В частности, при угле наклона плоскости равном 60^o, следует выбирать окружную скорость преграды равной V_с = V (1,25-0,46R). При различных возможных значениях коэффициента восстановления R имеем 0,79V<V_с<1,25V.Depending on the value of V _c / V and the parameter of the formula γ, the pieces after the impact can have either positive or negative horizontal velocity of the center of mass, i.e. move either in the direction of rotation of the cylindrical barrier, or in the opposite direction. This fact is used in the proposed method for separating flaky pieces from cubical ones. As you know, flocks are considered pieces whose length is three or more times their width or thickness. This boundary aspect ratio corresponds to the shape parameter γ = γ _gr = 0.32. We choose the peripheral speed of rotation of the cylindrical surface V _with so that for γ = γ _{gr the} impact velocity of the piece would be zero:

Thus, we provide the movement of ice and cuboid pieces in opposite directions from the point of impact. In particular, when the angle of inclination of the plane is 60 ^o , you should choose the peripheral speed of the barrier equal to V _s = V (1.25-0.46R). For various possible values of the recovery coefficient R, we have 0.79V <V _with <1.25V.

 1. Handbook of coal preparation. - M .: Nauka, 1974, p. 204.

 2. Recommendations for the production of improved form gravel for road construction. SoyuzdorNII. - M., 1969.

Claims (1)

 A method for separating bulk material in a shape by feeding it onto an inclined plane, characterized in that the material is immediately impacted with a rotating cylindrical surface immediately after sliding on the plane.

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