A method and apparatus for agglomeration of powders

 

The invention relates to a method and apparatus for agglomeration of powders, in particular food products such as instant coffee, coffee substitutes, vegetable proteins, milk and similar milk products, and also dyes and agrochemicals. In the method of sintering the powder is brought into contact with agglomerated fluid medium in the direction of the moving surface on which the agglomerated powder is collected. Then agglomerated powder is moved to a distance from the moving surface by centrifugal force. While all areas of the moving surface moves at the same speed. The agglomerated powder is moved to a distance from the moving surface by means of centrifugal acceleration, which shall be at least 50 m/s². A device for implementing the method comprises a moving surface for collecting the agglomerated powder, means for bringing the powder to be agglomeration, in contact with one or more agglomerated liquid media under the direction of the moving surface, and means for driving the specified surface. The moving surface has a configuration that enables per the firm obtain agglomerated powder when the centrifugal acceleration, at least 50 m/s²to move a distance from the moving surface. The invention provides a uniform size distribution of agglomerated particles, does not require re-treatment, worsening the quality of the product. 2 C. and 24 C.p. f-crystals, 3 ill., 1 PL.

The present invention relates to a method and apparatus for agglomeration of powders, in particular food products such as instant coffee, coffee substitutes, vegetable proteins, milk and similar milk products etc. and, in addition, dyes and agrochemicals, using a process that is widely known as agglomeration with re-wetting.

From U.S. patent No. 3966975 And the content of which is incorporated into the present application by reference, a method and apparatus for producing agglomerated instant coffee or powdered products, the replacement of coffee, in which the powder source material is lowered in the direction of the rotating disk while wetting, the original materials wetted by water humidifier in a quantity sufficient to cause agglomeration of the starting materials, and the disc rotates at a rotational speed, d is b and the device according to U.S. patent No. 3966975 And widely used for many years. They are easy to use, but still have certain disadvantages. Due to the fact that the different parts of a rotating disk are moved with different speeds are obtained agglomerated particles with a wide size distribution. This means that to obtain an acceptable efficiency of the process, a large fraction of particles with sizes beyond the nominal size, usually must be returned for re-processing. However, accompanying this recurring processes of wetting and drying of the circulating product will degrade the quality of the product. An additional disadvantage is that the design of the device makes the device unsuitable for production increase due to practical constraints associated with the capacity of the nozzle.

The present invention is directed to an improvement of the method and device according to the above U.S. patent, the implementation of which the disadvantages mentioned above are partially eliminated.

According to the present invention a method for agglomeration of powders, in which the powder is liable to agglomeration, bring into contact with agglomerated fluid medium when napravlenikh move to a distance from the moving surface by centrifugal force, thus according to the invention all parts of the moving surface moves with essentially the same speed, and the agglomerated powder is moved to a distance from the moving surface by centrifugal acceleration of at least 50 m/s².

Using characteristic consists in the fact that all areas of the moving surface moves with essentially the same speed, get more uniform size distribution of agglomerated particles, leading to the decreasing rate of return for re-processing and better quality products. In addition, the speed of a moving surface becomes relevant parameter to control the size of the agglomerated particles.

The agglomerated powder is removed from the surface of the moving surface by centrifugal acceleration, comprising at least 50 m/s²usually centrifugal acceleration is in the range from 50 to 5000 m/s², preferably in the range from 100 to 2500 m/s²and more preferably in the range from 200 to 1250 m/s². Thus agglomerated powder is obtained directly in the form of particles, in contrast to some other methods known GSAT mechanically.

The moving surface is usually move with a speed of at least 2.5 m/s, preferably with a speed of at least 3.5 m/s and more preferably at a speed of at least 5.0 m/s, it is Preferable to adjust the speed of the moving surface to change the size of the particles agglomerated powder.

The moving surface can be performed essentially impermeable to fluid.

The moving surface can be performed in the form of a curved surface of a cylinder or drum rotating around its Central axis.

You can use the cylinder or drum having a diameter ranging from 0.25 to 1.50 m, preferably in the range from 0.35 to 1.00 PM

The cylinder or drum can be rotated with a rotational speed ranging from 80 to 2000 rpm, preferably with a speed ranging from 100 to 1000 rpm

Agglomerated powder can be sorted and powdered part of the guide for additional agglomeration.

The powder may be a powder of coffee and/or powder, substitute coffee.

Agglomerated powder can be dried.

Another object of the present invention is a device for agglomeration of powders containing a moving surface is one or more agglomerated liquid media under the direction of the moving surface, and means for driving the moving surface, with the configuration, ensure that the movement of the collected agglomerated powder on the distance from the moving surface under the influence of centrifugal force during operation of the device. According to the invention the moving surface has a configuration that enables the movement of all its sites with essentially the same speed during operation of the device, and the device is configured to receive the collected agglomerated powder when the centrifugal acceleration of at least 50 m/s²to move a distance from the moving surface.

The device may be configured to receive the collected agglomerated powder when the centrifugal acceleration in the range from 50 to 5000 m/s², preferably in the range from 100 to 2500 m/s²and more preferably in the range from 200 to 1250 m/s².

Means for driving the moving surface may be configured to move the moving surface with a speed of at least 2.5 m/s, preferably with a speed of at least 3.5 m/s and more preferably at a speed of at least 5.0 m/s

Means for bringing the powder to be agglomer what those powder, with steam (saturated or superheated), or a combination of these substances, at a time when the powder is in the air, known from the prior art (see, for example, the above-mentioned U.S. patent No. 3966975 and EP 0204256 Century All such funds is also well applicable in the method and device according to the invention as long as they are compatible with this product and with all the other characteristics of this method and device. In most cases, they contain a set of feed tubes or other means for distribution of the powder over the area moisturized and means of spray agglomerated fluid or agglomerated fluid to bring the spray agglomerated fluid or fused agglomerated fluid in contact with the powder. As an example, the spray means can be mentioned injection or air atomizing nozzle. Configuration means for bringing the powder to be agglomeration, in contact with agglomerated fluid medium or agglomerated liquid media under the direction of the powder to the moving surface is not critical, because the corresponding contact is carried out without undue contamination of the equipment. Can the Yes provide additional funds they usually have consistently in the direction essentially perpendicular to the direction of movement of the moving surface for a sufficiently uniform distribution thereof over the surface. In addition, the means for bringing the powder to be agglomeration, in contact with agglomerated fluid medium or agglomerated fluid environments can be made in the form of adjacent oval slits for insertion, respectively, of the powder and agglomerated fluid.

In the preferred in the present embodiment of the invention the means for reduction of powder that is subjected to agglomeration, in contact with one or more agglomerated liquid media under the direction of the moving surface includes one or more pipes, each of which has an essentially circular opening for the introduction of powder that is subjected to agglomeration, and the tube located centrally within each of the annular openings for the introduction of agglomerated fluid or agglomerated fluid and selectively spraying gas, at this centrally located pipe ends with a spray nozzle on the output level of the ring holes.

As mentioned above, you can easyline liquid together with gas nozzle is a nozzle for two fluid media, the fluid usually use water or an aqueous solution of the powder, and as the gas is usually used air, inert gas, for example nitrogen, or saturated steam, or superheated steam, or a mixture of several components of the above. Steam has the dual effect of increasing as humidity and temperature.

To reduce the danger of contamination of the pipe for introducing the powder spray nozzle can be positioned so that it is performed at a small distance relative to the output ring surrounding the hole.

Means for bringing the powder into contact with agglomerated fluid medium or agglomerated fluid environments must be placed at such a distance from the moving surface to hydrated powder hit the surface with a force sufficient to perform agglomeration without destruction to an unacceptable degree of the resulting aggregates. Specialist in the art can easily determine the desired distance with respect to a particular product.

In accordance with a preferred hallmark of the distance between the moving surface and the outlet means for bringing the powder to be agglomeration is generated.

Typically, the means for bringing the powder to be agglomeration, in contact with agglomerated fluid medium or agglomerated fluid-fluid should be at a distance of from 0.10 to 1.00 m from the moving medium, for example, at a distance of from 0.20 to 0.80 m

The moving surface should generally be essentially impermeable to fluid, although in some cases it may be acceptable in certain porosity. However, from the viewpoint of ease of removal of the agglomerated particles from a moving surface the surface should be a smooth continuous surface. In addition, to improve the slip characteristics, the surface can be provided with a covering layer, for example a layer of Teflon®.

In a particularly preferred embodiment, which significantly facilitate installation and compact design, the moving surface is a curved surface of a cylinder or drum, for example a massive cylinder or drum with a shell made of steel or other metal, selectively provided with a top layer to improve the characteristics of the slip.

For the cylinder or drum of the centrifugal acceleration can be calculated following the author acceleration, m/s²;

r is the radius of the cylinder or drum, m;

angular frequency, with^-1.

The above equation can be rewritten as:

and_with=DN²_rpm/182,56,

where a_withcentrifugal acceleration, m/s²;

D - diameter of the cylinder or drum, m;

N_rpm- the number of revolutions per minute.

In addition, the equation can be transformed into:

N_rpm=13,51and_with.

The speed of a moving surface, v₀can be determined as follows:

V₀=0,0523DN_rpm.

The cylinder or drum should generally have a diameter ranging from 0.25 to 1.50 m, preferably in the range from 0.35 to 1.00 m, and usually it should be able to rotate with a rotational speed ranging from 80 to 2000 rpm, more preferably with a speed ranging from 100 to 1000 rpm

In the General case of a moving surface, and means for bringing the powder to be agglomeration, in contact with one or more agglomerated liquid media under the direction of a given surface are accommodated in the housing, while the tool is over in the Lee of the drum, the means for bringing the powder to be agglomeration, in contact with one or more fluid-fluid in the direction to the surface usually have so that it is held essentially vertically above the axis of rotation, or it can be positioned so that it was held at a small angle, for example at an angle from 5 to 45and/or was offset by a small distance, for example at a distance of from 1 to 10 cm, up in the direction of rotation to ensure the best capture glomerulosa product. However, this tool can also be positioned at other locations around the moving surface, usually on the spot between “9 o'clock” and “3 hours”.

To avoid condensation in the enclosure is usually served with a stream of heated gas secondary treatment. In the case of instant coffee or coffee substitute, ambient air is heated to a temperature of from about 55 to 70for example a temperature of approximately 60will be suitable. In addition, the housing can be provided with an insulating sheath to avoid condensation on the walls of the shell.

Optionally agglomerated powder after retiring from moving Poveda perforated plate or in a fluidized bed dryer, such as VIBRO-FLUIDIZER®, which can be located outside the enclosure or partially or completely inside the housing, for example in the form of built-in site at the bottom of the housing. Additional drying should be carried out so that the formed agglomerates are not damaged in unacceptable degree.

The dried powder is usually sorted after drying, and the product low size, called “dust”, return for additional agglomeration. The product is oversized can also be returned to the agglomeration after additional processing, such as crushing or grinding.

Optionally agglomerated powder can also be sorted before the final drying. However, due to the fact that by means of the method and device according to the invention can be obtained particles of relatively uniform size, in many cases, this additional sorting in the wet state can be omitted.

Particles carried by the gas flow coming out of the case, including possible after additional drying, can be separated in cyclones or similar devices, are widely known from the prior art, and if desired, returned for additional processing.

Below Crestline, which, however, should not be construed as limiting the scope of invention.

In the drawings shows the following:

Fig.1 depicts a schematic view of the device according to the invention containing a fluidized bed dryer, outside the enclosure;

Fig.2 is a schematic view of the device according to the invention with integrated fluidized bed dryer for further drying the agglomerated powder;

Fig.3 is a schematic view of the device according to the invention with a built-in belt conveyor for further drying the agglomerated powder.

In Fig.1 shows a device 1 that is designed for sintering powder 5, for example coffee or powder substitutes coffee, and containing a rotating steel cylinder 2, which forms the running surface 4, and the pipe and to allow the node 3 to bring powder 5 subject areas, in contact with agglomerated fluid medium, which is directed toward the moving surface 4. Powder 5 subject areas, is introduced through pipe 6 pipe 7 having a circular hole at the end of which he meets with water and steam, introduced through the pipes 8 and 9 respectively located in the Central tube 10, the end is verste ring pipe 7. This is achieved by surface wetting of the powder particles and water vapor introduced as agglomerated fluid, leading to the fact that the particles form agglomerates as they are directed toward the moving surface of the rotating cylinder. The cylinder 2 and the pipe and to allow the node 3 is installed in the insulated housing 12 (insulation not shown), in which the pipe 13 is introduced heated air for partial drying of the agglomerated particles and avoid condensation. The drying air leaves the housing through the pipeline 14. The cylinder 2 rotates at such a speed that agglomerated and partially dried powder is displaced by the distance from its surface under the influence of centrifugal acceleration.

Agglomerated powder out of the lower part of the housing 12 through the pipeline 15 (may have not shown conveying means), and enters the dryer 16 fluidized bed for additional drying after optional shown passing through a sieve. Dryer 16 fluidized bed (selectively supply not shown vibrating means) includes a perforated plate 17, which is further drying the agglomerated powder, when toprovide 40 from the dryer fluidized bed agglomerated powder is sorted on the sieve 20, this product meets the requirements of the size is removed through the pipe 21, and the dust is sent for re-processing through the pipeline 22 and after passing through the cyclone 24 is mixed with the source material coming from the hopper 23, and the product of inflated size is removed through line 25 for further processing, if it is necessary, for example, for crushing or grinding.

Air transport is introduced by pipes 26 and 27. The pipe 26 has a blow-off valves 28, 30 and the pipe 27 to the purge valve 29. Particles captured by the drying gas leaving the housing 12 through the pipe 14, and a drying gas leaving the dryer 16 fluidized bed through the conduit 31, separated in the cyclone 32 and combined with the original material from the hopper 23 by means of the conveyor 33. The air leaves the unit through the pipeline 34.

In Fig.2 shows a variant implementation of the device according to the invention with integrated fluidized bed dryer for further drying the agglomerated powder. As shown in Fig.1, the moving surface 4 is a curved surface of the cylinder 2, but in this embodiment, the cylinder can be with the but of the cylinder. Pipe-to allow the node 3 shown in Fig.1 except that tripling the performance of the device compared to a device having only a single nozzle, three pipe and nozzle node 3 are arranged one behind the other on the same line along the elongated cylinder. In addition, for additional drying of the agglomerated product of the lower part of the housing 12 is elongated to create space for a built-in dryer 16 fluidized bed. If this fluidized bed dryer equipped with a vibrating tool, you can use the flexible wall 50 for connecting the walls of the housing 12 with the walls of the dryer 16 fluidized bed. Hot air is introduced into the dryer 16 fluidized bed in the space 18, and the cooling air 19. Optionally dried and cooled agglomerated product exits the dryer fluidized bed through the pipeline 40, and a drying gas exits the dryer fluidized bed through the conduit 31.

In Fig.3 shows a variant implementation of the device according to the invention with a built-in belt conveyor for further drying the agglomerated powder. The moving surface 4 is kivalina the e implementation it is made so, what takes place at an angle corresponding to about “11 o'clock” on the drum. The lower part of the elongated body to form a space with a perforated conveyor belt 37, which is further drying the agglomerated powder. As shown in Fig.2, the hot air is introduced through the pipe 18, and the cooling air through the pipeline 19. The drying gas passes through the conduit 31, and chilled agglomerated product goes through the pipeline 40.

Examples

Using the device, the construction of which is similar to the one shown in Fig.1, when the conditions specified in the table below, was implemented agglomeration of powdered coffee and powdered mixtures of coffee and chicory.

The diameter of the agglomerated drum was 0.5 m and the distance between the nozzle and the drum was made of 0.33 mm

The powder is liable to agglomeration, was injected through the annular opening at the rate of 50 kg/h of the Agglomerated liquid was water, rashpilevskaja ferry at the centrally located nozzle for two fluid media.

The product was further dried in a three-section of the fluidized bed dryer using two sections for drying and one for final cooling.

The device contained sieve ohms.

Claims

1. How agglomeration of powders, in which the powder is liable to agglomeration, bring into contact with agglomerated fluid medium in the direction of the moving surface on which the agglomerated powder is collected and then agglomerated powder is moved to a distance from the moving surface by centrifugal force, characterized in that all areas of the moving surface moves with essentially the same speed and agglomerated powder is moved to a distance from the moving surface by means of centrifugal acceleration, which shall be at least 50 m/s².

2. The method according to p. 1, characterized in that use centrifugal acceleration in the range from 50 to 5000 m/s², preferably in the range from 100 to 2500 m/s²and more preferably in the range from 200 to 1250 m/s².

3. The method according to p. 1 or 2, characterized in that the moving surface is moving with a speed of at least 2.5 m/s, preferably with a speed of at least 3.5 m/s and more preferably at a speed of at least 5.0 m/s

4. The method according to any and the>/p>5. The method according to any of paragraphs.1-4, characterized in that the moving surface is performed in the shape of a curved surface of a cylinder or drum rotating around its Central axis.

6. The method according to p. 5, characterized in that use cylinder or drum having a diameter ranging from 0.25 to 1.50 m, preferably in the range from 0.35 to 1.00 PM

7. The method according to p. 5 or 6, characterized in that the cylinder or drum rotates with a rotational speed ranging from 80 to 2000 rpm, preferably with a speed ranging from 100 to 1000 rpm

8. The method according to any of paragraphs.1-7, characterized in that the agglomerated powder sort and pulverized part of the guide for additional agglomeration.

9. The method according to any of paragraphs.1-8, characterized in that the powder is a powdered coffee and/or powder, substitute coffee.

10. The method according to any of paragraphs.1-9, characterized in that the agglomerated powder is dried.

11. Device for agglomeration of powders containing a moving surface for collecting the agglomerated powder, means for bringing the powder to be agglomeration, in contact with one or more agglomerated liquid media under the direction of the moving surface, and means DL agglomerated powder on the distance from the moving surface under the influence of centrifugal force during operation of the device, characterized in that the moving surface has a configuration that enables the movement of all its sites with essentially the same speed during operation of the device, and the device is configured to receive the collected agglomerated powder when the centrifugal acceleration of at least 50 m/s²to move a distance from the moving surface.

12. The device according to p. 11, characterized in that it is made with the possibility of receiving the collected agglomerated powder when the centrifugal acceleration in the range from 50 to 5000 m/s², preferably in the range from 100 to 2500 m/s²and more preferably in the range from 200 to 1250 m/s².

13. The device according to p. 11 or 12, characterized in that the means for driving the moving surface is configured to move the moving surface with a speed of at least 2.5 m/s, preferably with a speed of at least 3.5 m/s and more preferably at a speed of at least 5.0 m/s

14. Device according to any one of paragraphs.11-13, characterized in that the moving surface is made, essentially, is not permeable to fluid.

15. Device according to any one of paragraphs.11-14, characterized in that on p. 15, characterized in that the cylinder or drum has a diameter in the range from 0.25 to 1.50 m, preferably in the range from 0.35 to 1.00 PM

17. The device under item 15 or 16, characterized in that it comprises means for rotating the cylinder or drum with a rotational speed ranging from 80 to 2000 rpm, preferably with a speed ranging from 100 to 1000 rpm

18. Device according to any one of paragraphs.11-17, characterized in that the means for bringing the powder to be agglomeration, in contact with one or more agglomerated liquid media under the direction of the moving surface includes one or more tubes having essentially a circular opening for the introduction of powder that is subjected to agglomeration, and the tube located centrally within each of the annular openings for the introduction of agglomerated fluid or agglomerated fluid and selectively spraying gas, at this centrally located pipe ends with a spray nozzle on the output level of the ring holes.

19. The device under item 18, characterized in that the spraying liquid together with gas spray nozzle is a nozzle for two fluid media.

20. The device under item 18 or 19, characterized in that ustroystvo according to any one of paragraphs.11-20, characterized in that the means for bringing the powder to be agglomeration, in contact with one or more agglomerated liquid media under the direction of the moving surface is at a distance of from 0.10 to 1.00 m from the moving surface.

22. Device according to any one of paragraphs.11-21, characterized in that the distance between the moving surface and the outlet means for bringing the powder to be agglomeration, in contact with one or more agglomerated liquid media under the direction of the moving surface is adjustable.

23. Device according to any one of paragraphs.11-22, characterized in that the speed of a moving surface is adjustable.

24. Device according to any one of paragraphs.11-23, characterized in that it further comprises means for drying the agglomerated powder.

25. Device according to any one of paragraphs.11-23, characterized in that it contains a fluidized bed dryer for further drying and cooling the agglomerated powder.

26. The device according to p. 24, characterized in that it further comprises a belt conveyor for secondary drying and cooling the agglomerated powder.