SU1281290A1 - Rotor of centrifugal mixer of continuous action - Google Patents

Abstract

The invention relates to mixers of bulk materials and allows for an increase in the quality of the finished product. The mixed components continuously flow through the central part of the hole 2 into the inner space of the bowl 3 continuously rotating by the shaft 3. The inner surface of the bowl in the form of a concave curved surface of rotation and the cavity of the bowl in the upper part of the decreasing cross section create different along the rotor centrifugal field its mixing i effect on the mixed material of the zone of intense turbulence and recirculation with a large variety of speeds and the trajectories of the particles of the bulk material. 4 il.

Description

SL

The invention relates to a technique for mixing powdered and granular bulk materials and can be used in light, chemical and other areas of the national household.

The aim of the invention is to improve the quality of the finished product.

Figure 1 shows a rotor, a longitudinal section; Fig.2 is the same, top view; Fig. 3 shows the dependence of the relative velocity V of the movement of particles of the bulk material along the inner surface of the rotor from the current coordinate Zj in Fig. 4 shows the dependence of the magnitude of the normal reaction of the inner surface of the rotor N on the current coordinate Z.

The rotor of the continuous centrifugal mixer comprises a hollow bowl 1 rotating about a vertical axis with an outlet opening 2 mounted on the shaft 3.

The inner surface of the bowl is made in the form of a concave curved surface of rotation, while the cross-section of the bowl cavity in the upper part is made decreasing.

The radius vector forming the inner surface drawn from the vertical axis of rotation of the rotor and

pendicularly. to a known surface, first increases as

{/ magnitude of the current coordinate in the direction of the vertical axis of rotation

rotor, passes through its maximum value, and then decreases to a certain minimum limit value that determines the height of the inner surface of the rotor h, for example, of a spherical shape according to the formula

RC

IR

-min

(one)

where R, is the radius of the sphere;

min

the minimum value of the radius vector in the upper part of the int. the surface of the rotor. The limiting value of the minimum value of the radius vector in the upper part of the rotor depends on the values of the relative velocities of the particles of the bulk material and the normal surface reaction, which affect the turbulence and recirculation of the bulk material in the inner space of the rotor.

The value of the relative velocity of the particle V of the bulk material as it moves along the inner surface of the rotor, for example spherical, is determined by the formula

- (jl | l, +, .- f (Z, - K) Y2Y

where (l) is the angular rotational speed

rotor with

-one

RC f

g

Sphere radius, m; friction coefficient; current coordinate in the direction of the vertical axis of rotation of the rotor, m.

Dependence of the relative particle velocity V of the bulk material on the current Z coordinate; in the direction of the vertical axis of rotation of the rotor, for example, a spherical shape as it moves along the inner surface of the rotor is shown in FIG. 3, curves I - IV (the friction coefficient is taken, 5, curve I with Rg 0.1 MS Y 10; curve II with RC 0.1 m, i) 15 s curve III with Rj 0.15 m, U curve IV with Rg 0.15 m, U) 15 s)

The magnitude of the normal reaction of the surface N, arising from the pressure of particles of the bulk material moving along the inner surface of the rotor, is determined by the formula

 - .. .- .. i. ..-.- I,. , - ,, ,, ,,,,

Zf- sin (- | i - O, (2)

IСКС

2

-g cos ot + m and R sin ot, (3)

 - mass of the i-th particle

material, kg;

g - free fall acceleration,

L - the angle of inclination of the tangent to the inner surface of the rotor at the current point, degrees;

W is the angular velocity of rotation of jpoTopa,

R is the radius from the axis of rotation to the inner surface of the rotor, m

55

50

The dependence of the normal reaction of the inner surface of the rotor N on the current Z coordinate in the direction of the vertical axis of rotation of the rotor when a particle of a unit mass moves along a surface, for example, spherical, is shown in Fig. 4, curves I.-IV (curve I at RJ 0.1 m, tJ 10 s; curve II with R (, 0.1 m, U 15 curve III with RJ 0.15 m, U)

 10 s; curve IV at R. 0.15 m, (x) 15 s -).

The magnitude of the radius vector rj drawn from the vertical axis of rotation of the rotor and perpendicular to it to a known surface, for example, spherical, is determined by the formula

(four)

i t2R, Z. - Zj,

rj

where R is the radius of the sphere;

Z is the current coordinate in the direction of the vertical axis of rotation of the rotor.

Making the inner surface of the bowl in the form of a concave curvilinear surface of rotation, for example spherical, and making the bowl cavity in the upper part of the decreasing cross section create, across their entire centrifugal rotor field, different mixing effects on the material to be mixed into the intensive turbulence and recirculation zones with a wide variety of speeds and trajectories the movement of particles of the bulk material, which contributes to the achievement of the goal (fig. 3.4, curves I-IV).

The rotor of the centrifugal continuous mixer works as follows.

Loose blendable components in continuous flow through the central part of the hole 2 enter the inner space of the 3 bowl 1 continuously rotating with the help of the shaft. The mixing in the bowl results from the movement of the bulk materials along its inner surface with the proposed shape of the inner surface under the action of centrifugal

inertia forces I formula

m

defined by

-,

(five)

where t is the mass of the i-and: loose particles

medium, kg; tJ - angular rotation speed

rotor

R-- is the radius from the axis of rotation of the mouth to the 1st particle of the flowing medium, m

The speeds of the relative movement of particles of the bulk material during its movement along the inner surface of the rotor with the specified shape of the inner surface and the magnitude of the normal surface reaction increase to some limit Q.t.

speeds and magnitudes of nor-. surface reaction (Fig.3,4, curves I-IV), and then decrease to the values determined by the value of centrotational inertia. The speeds of movement of parallel bulk material, moving under the action of centrifugal inertia forces along the inner surface of the bowl, are different due to different radii determining the inertial forces acting on the particles of the bulk material, which leads to a decrease in the relative velocity of the particles of the material and the magnitude of the normal reaction

5 surface in the upper part of the inner surface of the rotating rotor as the parallel layers of the bulk material approach the axis of its rotation. Because of this, speed

0 relative particles displacements in parallel layers of the bulk material are different, and for individual particles the relative speed or the magnitude of the normal surface reaction drops to zero (figure 4, curves I - IV), which causes the particles to move this part of the bulk medium gravity forces down to the bottom of the rotor by moving up the particle layer

0 of the same bulk medium. The particles of loose material that have descended to the bottom of the rotor again begin to move up under the action of centrifugal inertial forces along the inner surface of the rotor, which

5 leads to intensive recirculation of the bulk material in the centrifugal field of the rotor.

Due to the fact that the figurative movement of the rotor is a rotator

As a result, Krriolis inertia forces I - arise, acting on the particles of the bulk material and determined by

formula

45

l (,, - 2ni, -UV-sin (w, V),

(6)

where t is the mass of the i-th particle loose

material, kg;

N — angular velocity of rotation of the rotor 50,

V is the relative speed of movement of the i-th particle of the bulk material along the inner surface of the rotating rotor 55 m / s.

Due to the fact that centrifugal and Coriolis forces of inertia of the trajectory of particles of granular material act on the particles of the bulk material.

 5, 1

moving along the inner surface of the bowl, in relative motion they have the form of spirals directed in the opposite direction of rotation of the bowl, which contributes to the exit of a part of the bulk material from the centrifugal floor of the Sropa into the outer space (figure 2),

The presence of the described effect during the movement of particles of the bulk material in the centrifugal rotor field leads to the fact that the proposed shape of the inner surface of the rotor, for example spherical, intensifies the mixing process by increasing the turbulence of the motion and the degree of recirculation of the particles of the bulk material in the inner space due to the specified expansion. In the case when the radius vector drawn from the rotor rotation and perpendicular to the inner surface of the cone, as in the known device, as the current coordinate increases in the direction of the vertical axis of rotation of the rotor, it only increases and reaches its maximum value only at the edge of the inner surface rotor, as a result, there is a constant increase in the relative velocity of the particles and the normal

(Rig. G

;five

81

2906

maximum surface reaction (Fig. 3 and 4, curves I, VI) of curve V with a radis in the lower part of a truncated downward-directed cone R 0.1 m, W 10 s; curve VI with

RI 0,1

m,

W 15 s

-one

what not to

leads to the presence of the described effect of movement of particles of bulk material in the centrifugal field of the rotor.

Experimental studies have shown that the proposed rotor implementation makes it possible to reduce the mixture heterogeneity coefficient as compared with the known embodiment (in the form of a cone), i.e. improve the quality of the finished product.

Claims (1)

Invention Formula A rotor of a centrifugal mixer with a continuous action, containing a bowl rotating about a vertical axis, characterized in that, in order to improve the quality of the finished product, the inner surface of the bowl is made in the form of a concave curved surface of rotation, the cross section of the cavity of the bowl in the upper part is made decreasing. 0.0 0.080.12 Fig.Z Z.M 0.16 0.2 Q.Otf- 0, OS 0.12 v,} 6 Lg ff, 2 0.2 Ia ««.