RU2241551C2 - Pneumatic chamber-type separator - Google Patents

Abstract

FIELD: mining and construction industry, agriculture and other branches of industry.

SUBSTANCE: separator has casing, dosing device, fan, inclined plate cascade, unloading devices for collecting of large-sized and fine fraction. Plate cascade is fixed in casing and positioned so that its inclination angle may be adjusted. Casing has preparing chamber and large-sized and fine particle separating chambers and is attached to carrier frame. Inclined plate cascade is positioned in preparing chamber, which is equipped with vibrator, shock-absorber and elastic collar for connection to large-sized particle separation chamber. Each plate of plate cascade is fixed at predetermined angle with respect to air flow. Large-sized and fine particle collecting devices are made in the form of replaceable pocket cassettes, which are fixed in bottoms of large-sized and fine particle separating chambers. Fine fraction separating chamber has increasing width of section transverse to air flow for reducing horizontal speed of medium flow.

EFFECT: wider operational capabilities and improved quality of material particle separation process.

4 dwg

Description

The invention can be used in the mining, construction industry, agriculture and other industries for the separation of bulk materials by density, size, particle shape.

State of the art

Known apparatus for the separation of bulk materials in different directions of air flows of various designs.

A distant prototype can be considered the well-known in the literature Bamag chamber apparatus / 1 /. This apparatus, designed to separate the fine-grained from the coarse-grained fraction of bulk materials, has a tapering chamber with two funnels equipped with augers to remove precipitated dust from it. In the upper part of the chamber there is a slot through which air is supplied, and a chute for supplying the source material past the named slot.

The method of separating the particles of the starting material by size is as follows: the starting material is fed from top to bottom by the feeder so that falling past the slit through which air is supplied at a certain speed and by means of which relatively thin particles are separated from larger, smaller particles by an air stream they are carried out into the chamber, where they settle and are removed by the screw, and large dedusted particles, falling past the slit, are removed from the apparatus as a finished product.

In this apparatus, the separation of grains of material by size is carried out only into two fractions of a given size. It is impossible to classify particles into several fractions on a narrow scale in this device. Due to the design features of the nodes, parts and their interconnections of this apparatus, the separation of particles occurs under conditions of relatively high turbulence of flows, the formation of vortices, which leads to a low efficiency of their separation. And separation by particle density in devices of this type, provided that the material is prepared according to the equidivisibility coefficient, for this reason is generally impossible.

The closest technical solution, which is taken as a prototype, is an air chamber separator (pneumatic classifier), which includes a housing, a classification chamber, a dispenser, a fan, an inclined cascade of planes, fixed in the cross section of the housing, installed with the possibility of adjusting the angle of its inclination, discharge bins for collection of large, medium and small fractions / 2 /.

Based on the above arguments and their experimental verification, the purpose of this invention was to develop technical elements / parts of nodes /, the interaction of which would provide an aerodynamic condition for the process of separation of particles of the separated material, as close as possible to the laminar regime, and the possibility of its regulation, as well as the creation of the ability to control the fractionation of the separated material by the number and dimension of the selected fractions due to:

1) reducing the vertical component of the rate of fall of particles when feeding material into the apparatus;

2) improvement of aerodynamic conditions when meeting the flow of material and air flow;

3) ensuring the uniformity of the material flow in the cross section of the apparatus and the conditions for the distribution of particles according to their properties during their separation;

4) providing relatively favorable conditions for the redistribution of particles along the trajectories of gladia, depending on their masses in the longitudinal section of the apparatus;

5) creating the possibility of fractionation of the separated material according to the number and uniformity of fractions by adjustable differentiation of the allocation of settled particles in the apparatus along its length.

This is achieved by the fact that in an air chamber separator for dry separation, including a housing, a dispenser, a fan, an inclined cascade of planes fixed in the housing, installed with the possibility of adjusting the angle of its inclination, unloading devices for collecting large and thin fractions, the separator housing is mounted on a carrier the frame and is made in the form of a preparatory chamber, chambers for the separation of large and thin particles of material, and an inclined cascade of planes is located in the preparatory chamber, which is equipped with a vibrator, shock absorbers and an elastic cuff of the connection with the separation chamber of large particles of material. Each of the planes is fixed at a certain angle of attack to the air flow, and the devices for collecting large and small particles are made in the form of replaceable cartridge pockets installed in the bottoms of the chambers for separating large and fine particles of material, and the chamber for separating fine-grained fractions is made with an increasing cross-sectional width in the longitudinal direction of the air flow to reduce the horizontal flow rate of the medium.

SUMMARY OF THE INVENTION

The aim of the invention was to create an apparatus for separating particles of bulk materials according to their properties / size, density, shape /, lacking the disadvantages of analogues, to implement the known method: gravitational separation of particles by their masses when they fall in a horizontal air stream, as a result of which the particles in the process movements depending on their masses acquire different fall trajectories, redistributing in space, settle at different distances from the beginning of movement, depending on their properties. The main factors determining the process of particle separation are the force of weight G = mg / where m is the mass of the particle, g is the acceleration of gravity / and the force perceived by the particle from a horizontal stream of air, or its dynamic pressure, is equal to P = ψ d ² c ² Δ / where c is the speed of the air stream, d is the particle diameter, Δ is the air density, ψ is the drag coefficient /, and the direction of the resultant of these forces is expressed by tg of the angle α with the horizon:

where δ is the particle density / cm. figure 1 /.

It can be seen from this that with the same specific gravity this angle will depend on their size, i.e. angle α will be larger for large particles;

therefore, larger grains are directed along a steeper trajectory downwards and quickly leave the sphere of action of the air flow, while smaller grains, moving hollow, are exposed to the jet longer and are therefore transferred to a greater distance, thus being redistributed along the length of the apparatus according to their masses . The phenomena that occur during the movement of particles in devices operating on this principle are actually much more complicated due to vortices formed in the air stream and when larger particles fall, the speed of which is comparatively high: and the higher these speeds, the greater the turbulence flows and, as a consequence, the deterioration of the process of separation of particles according to their properties.

From aerodynamics it is known that vortex motion occurs at a certain jet regime, characterized by the Reynolds parameter:

/ V is the air flow velocity, d is the diameter of the spherical particle, Δ is the density of the medium / air /, μ is the viscosity coefficient /. This shows that at constant values of d, Δ, μ, turbulence occurs after a certain critical value of the flow velocity or particle fall, and the lower these velocities, the better for the process, however, to a certain optimal value, otherwise the particle separation process will stop.

The invention is aimed at improving the quality of separation of particles according to their properties.

From the point of view of aerodynamics, the devices of the prototype under consideration have significant shortcomings, because of which their performance indicators in terms of quality / degree of accuracy / separation of particles by their properties wish to be better.

The listed objectives of the invention are aimed at:

1) reduction of the vertical component of the particle’s fall velocity when feeding them into the apparatus by dividing the total fall height in the apparatus into “n” segments by means of a cascade of planes located at an angle like an inclined staircase / hallmark /, which reduces the speed of the separated material by several times from top to bottom and increases the time of interaction of air and material flows and significantly reduces turbulence.

The feasibility and usefulness of the inclusion of this element in the apparatus of the apparatus is confirmed by simple calculation on the example of the movement of the particles depicted in figure 1.

The rate of fall of a particle in the apparatus from point A of the beginning to point B, the end of the fall is, as is known, V = V ₀ + gt,

where V ₀ is the initial fall velocity equal to 0 m / s;

g - acceleration of gravity, m / s ² ;

t - fall time, sec.

Let us denote the total height of the fall H and for simplicity of calculation we take equal to 1 m.

It is known that with free fall

,

,

from here we find the fall time

.

.

Since we adopted H = 1 m / separator height /, the particle fall time in the apparatus is

Assume that the cascade has 10 planes, which divides the height of the apparatus into 10 equal segments, i.e. H = 10 h

where h is the height between the steps of the cascade, m:

Let us determine the time of a particle’s incidence on a segment from a height h

The total time of a particle to fall from point A to point B with a cascade of 10 planes is

t _k = 0.14210 = 1.42 sec, i.e.

times more than without the cascade / positive result /.

The average particle fall rate from level A to level B without a cascade is

and with a cascade (Vк):

т.е.

those.

times less than without a cascade / positive result /.

Thus, the inclusion of a cascade of planes in three grooves reduces the average particle fall rate, which, accordingly, reduces the formation of vortices / turbulence / and increases the interaction time of the air flow with the material by a factor of three, which significantly improves the conditions for separation of particles.

In addition, the speed of the separated material along the cascade of planes depends on the angle of its inclination: the smaller the slope, the lower the speed of the material along the cascade down and vice versa. Therefore, the use of this factor to improve the conditions of the separation process and its regulation is advisable, for which the design of the apparatus includes elements for adjusting the angle of inclination of the cascade / Fig.2/, / distinguishing feature /, which depends on the mechanical properties of the separated material and a given aerodynamic process;

2) improving the aerodynamic conditions when meeting the flows of material and air by giving each plane of the cascade in the cross section a streamlined shape / distinctive feature /, like an airplane wing, which also reduces the likelihood of vortex flow formation that violates the regular redistribution of particles according to their properties / mass, shape /.

The usefulness of this design is obvious;

3) improving the process conditions by ensuring the uniformity of the flow of separated material on the planes of the cascade and between them, for which a vibrator is introduced into the set of technical elements /.

The listed elements, in terms of their functional relationships and the nature of the dynamics of their work — a dispenser, a cascade of planes, a vibrator — are mounted in one unit called the preparatory chamber;

4) improving the aerodynamic conditions of the process of redistributing particles along their paths of incidence in the longitudinal section of the apparatus according to their masses and shape for relatively coarse-grained fractions - the separator is equipped with a coarse-grained fractions chamber with pockets in the lower part to highlight the corresponding fractions / distinguishing feature /;

5) taking into account that, as particles move with an air stream along the apparatus, relatively large particles quickly fall out of the stream, and small particles remain, the size of which decreases with an increase in the path of their movement, and for their deposition, a corresponding change in the velocity regime of the flow is necessary. The speed regime, as is known, is characterized by the value of the Reynolds parameter

where V is the flow velocity, m / s, inversely proportional to the cross-sectional area of the channel, m is the diameter of the channel, Δ is the density of the medium / air /, μ is the coefficient of viscosity of air.

Transforming the expression Re as applied to the conditions of air movement in the separator, we obtain

,

,

where Q is the air flow, m ³ / s, Δ is the air density equal to 1.293 kg / m ³ , 1 is the width of the chamber, m, μ is the viscosity of the medium. Hence, a decrease in the value of the Re indicator should go in the direction of the air flow in the apparatus. From the above expression Re, this can be done by changing the value of l - the width of the chamber. Therefore, in the design of the separator is included a chamber for separating fine fractions with a variable cross-section / hallmark /. The above arguments on the Re indicator confirm the advisability of including this element in the separator device;

6) creating the possibility of expanding the number of separated fractions, their size and regulating these values - the separator design includes a device for the differentiation of settled particles along its length, consisting of cartridges equipped with pockets, which are replaced depending on the requirements for separation / distinguishing feature /.

The invention is illustrated by drawings.

Figure 1 is a diagram of the movement of particles of the separated material in the preparatory chamber with free fall in a horizontal air stream without a cascade of planes and with a cascade. Figure 2 - chamber separator, side view. Figure 3 - chamber separator, front view. Figure 4 - chamber separator, top view.

The implementation of the invention

At least three chambers are installed on the support frame 1 / Fig. 3, 4, 5 /: 2 — a preparatory chamber, 3 — a coarse-grained fraction chamber, and 4 — a fine-grained reaction chamber.

The preparatory chamber 2 is equipped with a dispenser 5 for uniform dispensing of the separated material into the chamber, with a cascade of 6 streamlined planes 7 in order to reduce the average fall rate of the material and increase the interaction time of the air flows and the separated material.

In order to regulate the angle of inclination of the cascade 6, on which the speed of separation of the separated material depends from top to bottom, the latter is fixed in the chamber by means of a hinge 8 and is equipped with a latch for its position 9. The angle of inclination β is selected experimentally in relation to the material properties.

In order to evenly distribute the material over the cross section of the chamber and the movement of particles along the planes of the cascade, the chamber is equipped with a vibrator 10 and shock absorbers 11. To prevent transmission of vibrations to subsequent chambers, it is connected to the coarse-grained fraction chamber 3 by means of an elastic cuff 12.

The separation chamber of coarse fractions 3 has the same cross section along the entire length to isolate coarse fractions, the number of which can be any, if necessary, is provided in the lower part of the pocket cartridge 13.

The chamber of fine-grained fractions 4, in order to change the dynamic air flow regime, respectively, of the size of the deposited particles, has an increasing cross section in the longitudinal direction of the air flow due to the width of the chamber and, similarly, the previous chamber, is equipped with a pocket cartridge 14 and a hatch 15 for stripping it and connected to a fan to create an air stream and clean it from ultrafine dust, which are not shown in the drawings as being not elements of the invention.

According to the task in the development of the invention, which was to create a separator design with relatively high technological parameters for separating particles of separated materials according to their properties, in other words, in order to increase the separation efficiency for one of the particle properties / particle size, density, shape /, in comparison with similar, by improving the aerodynamic conditions of the separation process by incorporating new structural elements into the apparatus design that differ in both form and function nym relationships. The goal, as the model tests showed, is achieved.

The separation process in this invention is carried out by a known method, which can be briefly characterized as the separation / or classification / of solid particles by their particle size or density, provided that the coefficient of equidivisibility is observed, in shape, for example, in the separation of mica, asbestos ores, etc., with free their falling in a horizontal stream of air.

In practice, the separation process is as follows. Set the cartridge pockets 13, 14 in the chambers of coarse-grained and fine-grained fractions with the corresponding number of pockets of a given number of fractions. A set of cassettes is included in the separator kit. The fan is put into operation, a predetermined air flow rate is set in the preparatory chamber 2 / for example, 3 m / s / by means of a throttle and a device that changes the speed pressure of the air flow. A vibrator 10 is launched, then a dispenser 5, which delivers a predetermined quantity of material to the separator per unit time.

Particles of the material under the influence of the vibrating planes 7 of the cascade 6 are evenly distributed over them in width and height / monolayer / and, when braked, fall from the plane onto the plane of the cascade, while being exposed to a horizontal air flow in each section of the fall, which changes the path of the particles according to their masses As a result of which they are separated by size, if the particles have the same density, by density, if they have the same size, or by shape. In this case, the particles are redistributed so that heavy particles fall out at the beginning of the separator, decreasing in their masses towards the end of the apparatus. Fractionation of fallen particles is carried out by means of cassette pockets 13, 14.

After separation, the fractionation of material by means of pocket cartridges can be changed by combining fractions in various combinations depending on the requirements for the granular composition of the finished product.

Bibliographic data

1. Lyashchenko P.V., prof. Gravity enrichment methods. M .: ONTI, 1935, p. 313-317.

2. Handbook of ore dressing. T.1. M .: Nedra, 1972, p.272.

3. SU 1459736 Al, B 07 B 4/08, 02.23.1989, 4 s.

Claims (1)

An air chamber separator for dry separation, comprising a housing, a dispenser, a fan, an inclined cascade of planes fixed in the housing, mounted with the possibility of adjusting the angle of its inclination, unloading devices for collecting large and thin fractions, characterized in that the housing is mounted on a supporting frame and made in the form of a preparatory chamber, chambers for the separation of large and thin particles of material, and an inclined cascade of planes is located in the preparatory chamber, which is equipped with a vibrator, shock absorbers and elastic cuff of the connection with the separation chamber of large particles of material, each of the planes is fixed at a certain angle of attack to the air flow, and devices for collecting large and small particles are made in the form of removable cartridge pockets installed in the bottoms of the chambers for the separation of large and thin particles of material, and the camera for the separation of fine fractions is made with an increasing width of the cross section in the longitudinal direction of the air flow to reduce the horizontal flow rate of the medium.

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