Fluidized bed jet mill and milling method

Abstract

The invention relates to a fluidized bed jet mill which comprises a barrel, a fine powder channel connected with an air draft system, a powder classifier installed in a classification chamber, a powder supply device connected with a powder inlet chamber, and at least one pair of powder spray pipes installed on the barrel of a crushing chamber, outlets of each pair of powder spray pipes are oppositely arranged in the crushing chamber in the radial direction, inlets of the powder spray pipes are connected with first Venturi powder pumps respectively, and coarse powder return pipes are connected between powder inlets of the first Venturi powder pumps and the coarse powder channel, so that coarse powder separated from the grading chamber is crushed in the crushing chamber. Coarse powder mixed with high-pressure airflow collides in the crushing chamber through the powder spray pipe, so that collision is targeted, only coarse powder is beaten, the crushing efficiency is improved, the crushing effect is greatly improved, and the particle size of the powder is effectively controlled.

Description

Technical Field

[0001] The invention relates to the field of powder pulverizing equipment, and in particular to a fluidized bed air flow mill and a powder making method. Background Art

[0002] There are many types of air jet mills, most of which are collision air jet mills. Up to now, the fluidized bed air jet mill is generally recognized as the best and most common type of air jet mill.

[0003] Conventional fluidized bed jet mills Figure 1 As shown, it includes a cylindrical barrel 10, the middle part of the barrel is a feed pipe 11, at least one pair of high-pressure nozzles 12 are arranged at the bottom, and a motor and a powder classification impeller 13 are installed at the top. The screw conveying device or the venturi pump conveying device adds the required powder through the feed pipe, and the high-pressure gas ejected from the relative high-pressure nozzle usually reaches supersonic speed, driving the powder in the barrel to collide, and the high-speed collision powder is crushed. The motor drives the classification impeller to rotate, and the extraction inside the classification impeller extracts the finer powder to the subsequent cyclone separator or capture device for collection and recovery. We control the fineness of the powder to be separated by controlling the rotation speed of the classification impeller. The faster the rotation speed, the finer the particle size.

[0004] Traditional fluidized bed jet mills have several disadvantages. First, after the high-pressure airflow is ejected from the nozzle, it is difficult to drive enough powders to collide within a very short distance and time. Second, no matter coarse powder or fine powder, there is a chance that it will be driven to collide and crush again, causing the powder that has been crushed to the required fineness to be further crushed. The powder particle size cannot be controlled, and a fine powder product with an unwanted particle size distribution is obtained. Summary of the invention

[0005] The technical problem to be solved by the present invention is: to overcome the shortcomings of the prior art and provide a fluidized bed airflow and powder making method to solve the technical problem that in the operation process of the previous airflow mill, it is difficult to drive enough powders to collide within a very short distance and in a very short time, and no matter coarse powder or fine powder, there is a chance that it will be driven again for collision and crushing, so that the powder that has been crushed to the required fineness can be further crushed, thereby obtaining unnecessary ultrafine powder.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] First aspect:

[0008] A fluidized bed jet mill is provided, comprising:

[0009] A cylinder, wherein a grading chamber, a powder feeding chamber and a crushing chamber are arranged in sequence from top to bottom, the grading chamber is connected to a fine powder channel and a coarse powder channel, and the fine powder channel is connected to an exhaust system;

[0010] A powder classifier is installed in the classification chamber, and an air outlet of the powder classifier is connected to the fine powder channel, so that the fine powder separated by the powder classifier is discharged from the fine powder channel;

[0011] A powder supply device, which is connected to the powder inlet chamber and is suitable for inputting powder into the powder inlet chamber;

[0012] At least one pair of powder nozzles are installed on the cylinder of the pulverizing chamber, and the outlets of each pair of powder nozzles are arranged radially opposite to each other in the pulverizing chamber. The inlets of the powder nozzles are respectively connected to the first Venturi powder pumps, and a coarse powder return pipe is connected between the powder inlet of the first Venturi powder pump and the coarse powder channel, so that the coarse powder separated in the grading chamber is pulverized in the pulverizing chamber.

[0013] Furthermore, the classification chamber and the powder feeding chamber are both cylindrical chambers.

[0014] Furthermore, the powder classifier and the fine powder channel are both located at the top center of the classification chamber;

[0015] The fine powder channel is opened at the center of the top of the classification chamber, and the coarse powder channel is opened at the side wall of the top of the classification chamber.

[0016] Furthermore, the powder supply device includes a powder inlet pipe and a second Venturi powder pump, the powder inlet pipe is tangentially arranged on the cylinder, and the second Venturi powder pump delivers new powder into the powder inlet chamber through the powder inlet pipe, so that the new powder rotates circumferentially in the powder inlet chamber.

[0017] Furthermore, the powder classifier is an impeller classifier.

[0018] Second aspect:

[0019] Provided is a powder making method, which adopts the above-mentioned fluidized bed air flow mill, comprising: new powder is fed into a powder feeding chamber through a powder feeding device, the new powder enters a classification chamber upwardly under the action of a new powder exhaust system, a powder classifier discharges the separated fine powder from a fine powder channel, and the remaining coarse powder is returned to each powder nozzle through a coarse powder return pipe, so that the coarse powder is carried in the high-pressure airflow sprayed from the powder nozzle, and the coarse powder is directly collided when being sprayed to be crushed, the crushed powder enters the classification chamber upwardly again for powder classification, the fine powder that meets the requirements is extracted, and the coarse powder is returned to the powder nozzle again for collision.

[0020] Furthermore, new powder enters the powder inlet chamber through a tangentially arranged powder inlet pipe, driving the new powder to rotate circumferentially in the powder inlet chamber. The rotation direction of the new powder in the cylinder is opposite to the rotation direction of the impeller in the powder classifier.

[0021] The beneficial effects of the present invention are:

[0022] The powder classifier discharges and collects the sieved fine powder directly through the fine powder channel, and the coarse powder is collected through the coarse powder return pipe and sent to the two first venturi pumps below. The coarse powder is mixed with the high-pressure airflow in the first venturi pump, and the coarse powder mixed with the high-pressure airflow collides in the crushing chamber through the powder nozzle. In this way, the collision is targeted and only the coarse powder is hit, which improves the powder crushing efficiency, greatly improves the crushing effect, and effectively controls the powder particle size.

[0023] The new powder carried by the second Venturi powder pump is input into the cylinder in a tangential direction, so that the new powder can rotate tangentially in the cylinder, which helps to separate the coarse powder to the inner wall of the cylinder and facilitates the coarse powder to enter the coarse powder channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is further described below in conjunction with the accompanying drawings.

[0025] Figure 1 It is a schematic diagram of a conventional fluidized bed jet mill;

[0026] Figure 2 Schematic diagram of the fluidized bed jet mill of the present invention;

[0027] Figure 3 is a cross-sectional view of the fluidized bed jet mill of the present invention in the grinding chamber;

[0028] Figure 4 is a cross-sectional view of the fluidized bed jet mill of the present invention in the classification chamber;

[0029] Among them, 1. cylinder;

[0030] 2. powder classifier, 21. motor, 22. powder classifying impeller;

[0031] 3. Powder spray pipe, 31. First Venturi powder pump;

[0032] 4. Second Venturi powder pump;

[0033] 51. Fine powder channel, 52. Coarse powder channel. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The present application provides a fluidized bed jet mill, which is described in detail below. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments of the present application. In the following embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0036] In order to solve the technical problem that in the prior art, it is difficult to drive enough powders to collide in a short distance and a short time during the operation of the air jet mill, and whether the coarse powder or the fine powder has the opportunity to be driven to collide and crush again, so that the powder that has been crushed to the required fineness is further crushed, resulting in unwanted powders, one embodiment of the present application provides a fluidized bed air jet mill. The following is a detailed description.

[0037] like Figures 2 to 4 As shown, a fluidized bed jet mill comprises

[0038] A cylinder 1, wherein a grading chamber, a powder feeding chamber and a crushing chamber are sequentially arranged in the cylinder 1 from top to bottom, the grading chamber is connected to a fine powder channel 51 and a coarse powder channel 52, and the fine powder channel 51 is connected to an exhaust system;

[0039] A powder classifier 2 is installed in the classification chamber, and an air outlet of the powder classifier 2 is connected to the fine powder channel 51, so that the fine powder separated by the powder classifier 2 is discharged from the fine powder channel 51;

[0040] A powder supply device, which is connected to the powder inlet chamber and is suitable for inputting powder into the powder inlet chamber;

[0041] At least one pair of powder nozzles 3 are installed on the barrel 1 of the pulverizing chamber, and the outlets of each pair of powder nozzles 3 are arranged radially opposite to each other in the pulverizing chamber. The inlets of the powder nozzles 3 are respectively connected to the first Venturi powder pumps 31, and a coarse powder return pipe is connected between the powder inlet of the first Venturi powder pump 31 and the coarse powder channel 52, so that the coarse powder separated in the grading chamber is pulverized in the pulverizing chamber.

[0042] like Figure 2 and Figure 4 As shown, the powder classifier 2 adopts an impeller classifier; the powder classifier 2 includes a motor 21 and a powder classifying impeller 22, the motor 21 is fixedly arranged outside the cylinder 1, and the powder classifying impeller 22 is located in the classifying chamber, and the powder classifying impeller 22 is driven by the motor 21 to rotate in the classifying chamber, and the powder classifying impeller 22 is blocked at the entrance of the fine powder channel 51, and the fine powder can enter the fine powder channel through the powder classifying impeller 22, while the coarse powder is blocked outside, and the coarse powder is finally sucked away by the negative pressure of the coarse powder channel 52 on one side.

[0043] In this embodiment, the number of the powder spraying tubes 3 is one pair. If the number exceeds one pair, each pair of powder spraying tubes 3 needs to be installed at a different height of the barrel 1.

[0044] Specifically, as an optional implementation in this embodiment, Figure 2 , Figure 3 and Figure 4 As shown, the grading chamber and the powder feeding chamber are both cylindrical chambers. The cylindrical chamber is conducive to the rotation of the powder in the chamber, and the rotation of the powder can separate the coarse powder to the inner wall of the chamber, and the fine powder can be retained in the center, which is convenient for the separation of coarse and fine powders.

[0045] Specifically, as an optional implementation in this embodiment, Figure 2 , Figure 3 and Figure 4 As shown, the powder classifier 2 and the fine powder channel 51 are both located at the top center of the classification chamber;

[0046] The fine powder channel 51 is opened at the center of the top of the classification chamber, and the coarse powder channel 52 is opened at the side wall of the top of the classification chamber.

[0047] The motor 21 of the powder classifier 2 passes through the subdivision channel and is inserted into the classification chamber. The powder classification impeller 22 is at the center. The rotation of the powder classification impeller 22 drives the powder to be rotated and separated in the classification chamber. During the rotation, the coarse powder is thrown to the cylinder wall, and the fine powder in the center is sucked into the fine powder channel 51 through the powder classification impeller 22.

[0048] Specifically, as an optional implementation in this embodiment, Figure 2 , Figure 3 and Figure 4 As shown, the powder supply device includes a powder inlet pipe and a second Venturi powder pump 4. The powder inlet pipe is tangentially arranged on the cylinder 1. The second Venturi powder pump 4 delivers new powder into the powder inlet chamber through the powder inlet pipe, so that the new powder rotates circumferentially in the powder inlet chamber.

[0049] The powder inlet of the second Venturi powder pump 4 is equipped with a feed hopper. The feed hopper is filled with the amount of new powder required to be crushed, and the new powder in the feed hopper is delivered to the powder inlet chamber through the second Venturi powder pump 4.

[0050] As another embodiment of the powder supply device, the powder supply device can also directly use a screw feeder. The new powder can be directly and slowly fed into the powder feeding chamber through the screw feeder, and the new powder first enters the classification chamber for classification, and the coarse powder is then mixed with the high-pressure airflow through the first Venturi powder pump 31 and sent to the crushing chamber for crushing.

[0051] In this embodiment, the second Venturi powder pump 4 is preferably the second Venturi powder pump 4, because feeding powder to the powder inlet chamber by the second Venturi powder pump 4 can drive the new powder to rotate tangentially in the powder inlet chamber, and the tangential rotation of the new powder in the cylinder 1 can separate the coarse powder in advance, which is more conducive to the classification of the powder in the classification chamber.

[0052] Conventional fluidized bed jet mills, such as Figure 1 As shown, new powder is first added into the cylinder 1 through the middle feed pipe, and then a pair of high-pressure nozzles at the bottom spray air, driving the powder in the cylinder 1 to fluidize and collide, thereby achieving powder crushing. During the crushing process, the powder includes subdivision and coarse powder. The fine powder will become ultrafine powder after collision again, which does not meet actual needs. The fluidized bed air flow mill of the present invention has powder nozzles 3 directly installed on both sides of the crushing chamber. The powder nozzles 3 are directly connected to the first Venturi powder pump 31. The first Venturi powder pump 31 is connected to the coarse powder channel 52 through a coarse powder return pipe, and the coarse powder in the cylinder 1 is collected separately. After the coarse powder is mixed with the high-pressure airflow of the first Venturi powder pump 31, the coarse powder + high-pressure airflow is sprayed into the crushing chamber, while in the past, only high-pressure air was sprayed. In the past, the high-pressure airflow was first hit into the chamber, and then the powder in the chamber was driven to collide, transmitting this powder collision force. The degree is relatively small, and the crushing efficiency is not high. Now the high-pressure airflow carries the coarse powder to collide directly in the crushing chamber. The high-pressure airflow speed output from the first Venturi powder pump 31 is supersonic, which directly makes the coarse powder and the coarse powder collide at a supersonic speed. The crushing quality is very high, and the colliding powder is more targeted. In the past, the colliding powder included fine powder and coarse powder, but now the colliding powder is coarse powder collected separately, which improves the efficiency of the crushing. Because the coarse powder collides with the coarse powder, it is also easier to control the powder particle size, which ultimately improves the powder making efficiency of the entire airflow mill.

[0053] In this embodiment, an adjustment plate for controlling the flow rate of the coarse powder inside is provided on the coarse powder channel 52. The adjustment plate moves radially on the coarse powder channel 52, thereby adjusting the flow rate of the coarse powder channel 52, and further controlling the amount of coarse powder entering the two first venturi powder pumps 31. If the amount of coarse powder colliding in the pulverizing chamber is too much, the pulverizing quality will be affected, therefore, it is necessary to control the coarse powder input amount of the first venturi powder pumps 31.

[0054] An embodiment of the present application provides a flour making method, which is described in detail below.

[0055] A powder making method, using the above-mentioned fluidized bed jet mill, such as Figures 2 to 4As shown, it includes: new powder is sent into the powder feeding chamber through the powder feeding device, and the new powder enters the classification chamber upward under the action of the new powder exhaust system, the powder classifier 2 discharges the separated fine powder from the fine powder channel 51, and the remaining coarse powder is returned to each powder nozzle 3 through the coarse powder return pipe, so that the coarse powder is carried in the high-pressure airflow sprayed from the powder nozzle 3, and the coarse powder is directly collided when being sprayed out to be crushed, and the crushed powder enters the classification chamber upward again for powder classification, the fine powder that meets the requirements is extracted, and the coarse powder is returned to the powder nozzle 3 again for collision.

[0056] Specifically, as an optional implementation in this embodiment, new powder enters the powder inlet chamber through a tangentially arranged powder inlet pipe, driving the new powder to rotate circumferentially in the powder inlet chamber, and the rotation direction of the new powder in the cylinder 1 is opposite to the rotation direction of the impeller in the powder classifier 2. Because the rotating powder-carrying airflow and the counter-rotating impeller make the separation of fine powder more selective.

[0057] The various devices selected in this application (components whose specific structures are not described) are all universal standard parts or components known to technical personnel in this field, and their structures and principles can be known to technical personnel through technical manuals or through conventional experimental methods.

[0058] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0060] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0061] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0062] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0063] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A fluidized bed jet mill, characterized in that it comprises A cylinder (1), wherein a classification chamber, a powder feeding chamber and a crushing chamber are sequentially arranged in the cylinder (1) from top to bottom, the classification chamber is connected to a fine powder channel (51) and a coarse powder channel (52), and the fine powder channel (51) is connected to an exhaust system; A powder classifier (2) is installed in a classification chamber, and an air outlet of the powder classifier (2) is connected to a fine powder channel (51), so that the fine powder separated by the powder classifier (2) is discharged from the fine powder channel (51); A powder supply device, which is connected to the powder inlet chamber and is suitable for inputting powder into the powder inlet chamber; At least one pair of powder nozzles (3) are installed on the barrel (1) of the pulverizing chamber, the outlets of each pair of powder nozzles (3) are arranged radially opposite to each other in the pulverizing chamber, the inlets of the powder nozzles (3) are respectively connected to a first Venturi powder pump (31), and a coarse powder return pipe is connected between the powder inlet of the first Venturi powder pump (31) and the coarse powder channel (52), so that the coarse powder separated in the grading chamber is pulverized in the pulverizing chamber.

2. The fluidized bed jet mill according to claim 1, characterized in that: The classification chamber and the powder feeding chamber are both cylindrical chambers.

3. The fluidized bed jet mill according to claim 2, characterized in that: The powder classifier (2) and the fine powder channel (51) are both located at the top center of the classification chamber; The fine powder channel (51) is opened at the center of the top of the classification chamber, and the coarse powder channel (52) is opened at the side wall of the top of the classification chamber.

4. The fluidized bed jet mill according to claim 2 or 3, characterized in that: The powder supply device comprises a powder inlet pipe and a second Venturi powder pump (4), wherein the powder inlet pipe is tangentially arranged on the barrel (1), and the second Venturi powder pump (4) delivers new powder into the powder inlet chamber through the powder inlet pipe, so that the new powder rotates circumferentially in the powder inlet chamber.

5. The fluidized bed jet mill according to claim 1 or 4, characterized in that: The powder classifier (2) is an impeller classifier.

6. The fluidized bed jet mill according to claim 1, characterized in that: The coarse powder channel (52) is provided with an adjustment plate for controlling the flow rate of the coarse powder inside.

7. A flour making method, characterized in that: The fluidized bed air flow mill according to any one of claims 1 to 5 comprises: new powder is fed into a powder feeding chamber through a powder feeding device, the new powder enters a grading chamber upwardly under the action of a ventilation system, the powder classifier (2) discharges the separated fine powder from a fine powder channel (51), and the remaining coarse powder is returned to each powder nozzle (3) through a coarse powder return pipe, so that the coarse powder is carried in the high-pressure airflow sprayed from the powder nozzle (3), and the coarse powder is directly colliding when being sprayed out to be crushed, and the crushed powder enters the grading chamber upwardly again for powder classification, the fine powder that meets the requirements is extracted, and the coarse powder is returned to the powder nozzle (3) again for collision.

8. The flour making method according to claim 7, characterized in that: New powder enters the powder inlet chamber through a tangentially arranged powder inlet pipe, driving the new powder to rotate circumferentially in the powder inlet chamber. The rotation direction of the new powder in the cylinder (1) is opposite to the rotation direction of the impeller in the powder classifier (2).

Images