MXPA06008782A - Separator for granular material - Google Patents

Abstract

The invention relates to a dynamic air separator which is used to separate granular powder materials into size fractions and which comprises a rotating cage(1). The inventive separator also comprises a chamber (2) which is intended for the recovery of fine materials and which is equipped with an outlet base. The aforementioned recovery chamber (2) is defined by a rotating casing (5) and is disposed co-axially in the extension of the aforementioned rotating cage (1), such that it can use the vortex created by said cage (1) for the cycloning of the material. Moreover, the recovery chamber (2) comprises openings in the casing (5) which enable the centrifuged material to move towards conduits (8) which are used to collect material located outside the chamber.

Description

SEPARATOR FOR GRANULAR MATERIAL FIELD OF THE INVENTION The present invention relates to the separation of granular materials, and in particular to the classification of similar powders or matepals by means of dynamic air classifiers.

STATE OF THE ART The separation of granular and powder materials into two factions with different grain sizes can be achieved by means of dynamic air classifiers. The related materials are powders with particle sizes up to 1,000 μm such as cement, limestone or lime, mineral dust and coal dust, among others. The capacities of the treated material vary from few tons to several hundred tons per hour. Dynamic classifiers have undergone several major changes allowing them to be classified into three large groups. The first generation, generally known by the names of "turbo", "heyd" or "whirlwind", has been improved by the second generation of the "wedag" type. The 3- generation is the most effective from the point of view of separation efficiency. The principle of operation of classifiers (O 'Know, Sturtevant SD, ...) is described in USP 4,551, 241 and EP 0 023 320. US 4,551,241 discloses a particle classifier provided with a lateral cyclone wherein the particles are driven and cycloned. The surplus is sent to the rotating cage of the sorter. The entire installation demonstrates a relatively volumetric and very complex design. EP 0 023 320 also shows a device for classifying granular materials with a lateral outlet for air charged with fine particles. This installation requires the use of filters and / or additional cyclones for the separation of fine materials.

OBJECTIVES OF THE INVENTION The present invention describes a dynamic air classifier that allows to avoid the use of external filters or cyclones, the recovery of fine materials occurs in the body of the classifier itself. The present invention also relates to a method for separation in accordance with grain size using the classifier of the invention.

BRIEF DESCRIPTION OF THE INVENTION The present invention describes a dynamic air classifier for the separation of granular and powder materials into fractions of grain size, comprising a rotating cage wherein: - said classifier also comprises a recovery chamber 2 for fine materials with a bottom output, said chamber 2 defined by a cover; - said recovery chamber 2 is arranged coaxially in the protuberance of the rotating cage 1 to be able to use the swirl created by the rotating cage to cyclone said material; - said recovery chamber 2 comprises openings in the cover 5 that allow the passage of centrifuged materials towards the collection conduits for the material located outside the chamber. Furthermore, according to the invention, said recovery chamber 2 can comprise fixed and / or movable deflectors (4, 7) for the purpose of modifying the air velocity and / or changing its direction. According to a preferred embodiment of the invention, said recovery chamber 2 for the fine materials is cylindrical or cone-shaped, the cone possibly open in the upper part or in the lower part. As an advantage, said recovery chamber 2 for the fine materials has a length corresponding to 2 to 6 times with the length of rotating cage 1 to have the required cyclone capacity and sufficient. In an especially preferred manner, said recovery chamber 2 for the fine materials and said rotatable cage 1 share the same vertical axis as the recovery chamber 2 placed below and extending from said cage 1. According to a first embodiment of In the invention, the deflectors 4 which are placed in the outlet part of the rotating cage 1 and / or in the recovery chamber 2 are driven by the rotation means of the cage 1 or by means of a separate device. According to a second embodiment of the invention, the deflectors 4 which are placed in the outlet part of the rotating cage 1 are fixed to said cage 1 by itself. The invention also specifies that the air extraction duct 3 passes through the outlet bottom of the recovery chamber 2, said duct having a diameter between 30 and 95% of the lower diameter of the recovery chamber 2 for the materials thin. Several openings and / or slots are preferably provided in the lower part of the recovery chamber 2. Furthermore, below said grooves and / or openings there is a plurality of conduits 8 leading to a means for transporting the material.

As an advantage, below said grooves and / or openings there is a plurality of conduits 8 leading to a circular hovercraft that transports the material to another means of transport. The classifier of the invention is also characterized by the presence of one or several deflectors 7 that are conical, cylindrical or radical (biased or straight) in the upper part of the bottom of the recovery chamber 2, outside the air extraction duct 3 , to minimize turbulence near the bottom of the chamber and to prevent material from being picked up again by air. In addition, the invention also shows the presence of a plurality of openings in the lower part of the cover 5 of the recovery chamber 2, these openings leading to collecting ducts for the fine material can be properly positioned (not shown). The present invention also discloses a separation method in accordance with grain size by means of a dynamic air classifier, comprising the following steps: feeding the material to be treated 13 to the rotary cage 1; - classify between large and fine particles in the rotating cage 1 depending on the speed of rotation and the air intake; - eject the large particles to the waste chamber 17; - recovering the fine materials in the recovery chamber 2 placed coaxially with the rotating cage; - using the swirl created by the rotating cage and possibly further accelerating by means of mobile or fixed baffles 4 for cycloning the fine material; - Separate the dedusted air and fine particles and extract the latter to a means of transport. Finally, the invention describes the use of the device described in claim 1 for the separation and classification of particles of mineral materials such as cement particles, glass brick, lime and coal dust.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the disposition of the classifier of the 3rd generation as in the state of the art. Figure 2 shows the layer the principle arrangement of the classifier as in the invention.

DETAILED DESCRIPTION OF THE INVENTION All types of classifiers operate in accordance with the same principle, which is shown in Figure 1. The central part of the classifier comprises a squirrel cage 1 which rotates about a vertical axis. This cage comprises separate plates or bars and is surrounded by paddles 4 which it allows to direct the air before it enters through the inlet volute 6 in the cage 1. The vanes 14 can also help to control the air flow. The material to be separated enters the classification zone defined by the outside of the cage 1 and the deflectors 4. The maximum size of the particles entering the cage with the air will be determined by the rotation speed of the cage 1 and the volume of air with which the classifier is fed. The larger particles remain outside the cage and are collected in the waste chamber 17. These large particles leave the classifier by gravity 10. The air charged with fine particles 15 leaves the cage either through the top or laterally and leaves the classifier through a conduit. The fine material is then recovered by means of one or more cyclones or filters outside the classifier body. In modern classifiers of the 3rd generation, the air enters the cage 1 with a tangential velocity of the same order as the peripheral velocity of the cage. The tangential component of the speed increases naturally when the air enters the cage 1 (swirling effect). The principle of the invention is shown in figure 2. This consists of using the swirl already created in order to cyclone the material to be treated 13 in a recovery chamber 2 adjacent to and coaxial with the cage 1, the dedusted air 12 leaves this recovery chamber 2 through an air extraction duct 3 whose inlet is located inside the recovery chamber 2. The dedusted air 12 is then sucked to one or more fans that send some of the air or everything from its back to the air inlet volute 6 of the finisher. The vortex created by the rotatable cage 1 can remain free or accelerated by fixed or movable deflectors 4 before entering said recovery chamber 2. These baffles 4 can also be placed in the recovery chamber 2 by itself. The fine material 11 is centrifuged in this recovery chamber 2 and will be concentrated in the external part of the chamber where it will be collected by means of openings in the walls (cylindrical and / or bottom cover) of the recovery chamber 2. The efficiency of recovery for fine materials 11 essentially depends on the particle size and its absolute density. For the same material, the important factors are the intensity of the swirl, that is, the tangential velocity of the entire air through the recovery chamber 2, the diameter of the recovery chamber 2 and the residence time of the particles in said chamber. camera. In other words, the important factors will be the diameter of the recovery chamber 2, its length and its tangential velocity of the air. The greater the tangential component of the air and the greater the chamber, the greater the efficiency of recovery. The invention in this way comprises a sorter with a cage, which is provided with a recovery chamber 2 for fine materials which fits coaxially into the protrusion of the rotating cage 1.

This recovery chamber for fine materials is cylindrical or conical (cone-shaped), the angle of the line that generates the cone with the axis of revolution of the cone preferably less than 30 °; the inlet diameter of the recovery chamber 2 for fine materials has the same order of size as the diameter of the cage 1 and has a length corresponding 2 to 6 times with the length of the cage 1. In the exit area of the cage 1 and / or in the recovery chamber 2, the fixed or mobile baffles 4 can be installed and the direction of the air currents will be allowed to be affected. The possible rotation of these baffles 4 can be induced when they are fixed to the cage 1 or on the other hand by placing them in movement by means which is independent of the cage 1. They can also be set in motion by the same means as the cage 1 without being fixed to the cage 1. said cage 1. The extraction duct 3 for the dedusted air 12 will be in this first part concentric to the recovery chamber and preferably will have a diameter between 0.3 and 0.95 times the lower diameter of the recovery chamber 2 in the plane of the entrance surface of said conduit. The outlet deflectors 7 can be placed here to control the direction of the air inlet at the conduit entrance. The recovery of the centrifuged material occurs when using the openings in the outlet bottom and / or in the lower half of the cover 5 of the recovery chamber 2. The sleeves or conduits 8 for the material are they provide opposites to these openings to collect and direct the material to traditional means of transport. The use of a coaxial recovery chamber in the protuberance of the rotating cage allows the swirl use already created by the cage and thus reduces the load losses of the air circuit. The invention allows to avoid the use of filters or cyclones external to the machine, thus simplifying its installation. An additional advantage is that the entire separation assembly is more compact, reduces installation engineering work, reduces installation costs and reduces pressure losses in the separation circuit.

Claims (14)

NOVELTY OF THE INVENTION CLAIMS

1. - Dynamic air classifier for the separation of granular and powder materials into fractions of different grain sizes comprising a rotating cage (1), wherein: - said classifier also comprises a recovery chamber (2) for fine materials with a exit bottom, said chamber (2) defined by a cover (5); - said recovery chamber (2) arranged coaxially in the protrusion of the rotating cage (1) to be able to use the swirl created by the rotating cage to cyclone said material; - said recovery chamber (2) comprises openings in the cover (5) that allows the passage of the centrifuged material towards the conduits (8) to collect the material located outside the chamber.

2. The classifier according to claim 1, further characterized in that said recovery chamber (2) comprises fixed and / or movable deflectors (4, 7).

3. The classifier according to claim 1, further characterized in that said recovery chamber (2) for fine materials is cylindrical or cone-shaped, the cone possibly open in the upper part or in the lower part.

4. - The classifier according to claim 1, further characterized in that said recovery chamber (2) for fine material has a length that corresponds 2 to 6 times with the length of the rotating cage (1).

5. The classifier according to claim 1, further characterized in that said recovery chamber (2) for fine materials and said rotatable cage (1) share the same vertical axis, the recovery chamber (2) placed below and extending from said cage (1).

6. The classifier according to claim 1, further characterized in that the deflectors (4) that are placed in the outlet part of the rotating cages (1) and / or in the recovery chamber (2) are driven by the means of rotation of the cage (1) or by means of a separate device.

7. The classifier according to claim 1, further characterized in that the detectors (4) that are placed in the outlet part of the rotating cage (1) are fixed to said cage (1) by itself.

8. The classifier according to claim 1, further characterized in that the air extraction duct (3) passes through the outlet bottom of the recovery chamber (2), said duct has a diameter between 30 and 95% of the lower diameter of the recovery chamber (2) for fine materials.

9. - The classifier according to claim 1, further characterized in that a plurality of openings and / or slots are provided in the bottom of the recovery chamber (2).

10. The classifier according to claim 9, further characterized in that there is a plurality of conduits (8) below said grooves and / or openings, leading to a means for transporting the material.

11. The classifier according to claim 9, further characterized in that there is a plurality of conduits (8) below said grooves and / or openings, leading to a circular hovercraft that transports the material to another means of transport.

12. The classifier according to claim 1, further characterized in that there is, in the upper part of the bottom of the recovery chamber (2), outside the air extraction duct (3), one or more conical, cylindrical deflectors or radial (biased or straight) (7) to minimize turbulence near the bottom of the chamber and to prevent the material from being picked up again by air.

13. The classifier according to claims 1 and 2, further characterized in that there is a plurality of openings in the lower part of the cover (5) of the recovery chamber (2), these openings lead to the conduits to collect the fine material. 14.- Separation method in accordance with the grain sizes by means of a dynamic air classifier, which includes following steps: - feed the material to be treated (13) to the rotating cage (1); - classify between large and fine particles in the rotating cage (1) depending on the speed of rotation and air intake; - expelling the large particles towards the waste chamber (17); - recovering the fine materials in the recovery chamber (2) placed coaxially with the rotating cage; - using the swirl created by the rotating cage and possibly also accelerated by the mobile or fixed deflectors (4) to cyclone the fine material; - Separate the dedusted air and fine particles and extract the latter to a means of transport.