JPH0318497B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention provides a method for reducing the pressure of pulverizing granular materials into ultra-fine powder by colliding milling gas-material mixture jets with each other using high starting pressures and temperatures. This is related to a chamber crushing device.

[Prior art and its problems]

The most commonly used feeding means for jet grinding equipment is an ejector, which is very inconvenient in terms of energy efficiency. When using an ejector, the material to be ground is conveyed to the grinding chamber by means of a gas jet. In this case, a considerable amount of air is also forced into the grinding device from the feeder funnel of the supply means. This impedes the pulverizing effect, and also has a negative effect on thermal efficiency since energy is lost by heating and compressing the air that has been mixed in. Furthermore, in the case of ejectors, the constancy of the material to be crushed is strictly required. Additionally, the ejector uses 20 percent of the total energy consumed by the grinding process, primarily to create the pressure difference.

To solve the above problems, a mechanical feeder was proposed in US Pat. A plug of material is created in the supply pipe immediately before the compressor, and the plug of material, which may be compressed in fractions, is forced into the crusher. The above US patent shows a push piston as an alternative to screw conveyors;
This avoids the problems that arise when the screw conveyor operates against considerable pressure resistance. On the other hand, the problem with the use of pistons is the variation in material supply, and the use of two supply pipes has been proposed as an improvement measure, but simply increasing the number of pipes does not sufficiently equalize the material supply. It cannot be said that the problem has been solved. Furthermore, the material plugs fed to the grinder must be broken down by the grinding gas, which has a significant negative effect on the grinding process itself. It is undesirable to feed the material into the mill in large chunks, as this will result in a temporary interruption of the milling process. This is even more obvious when you consider that the material remains in the mill for only a few tenths of a second.

In the device of Finnish Patent No. 62235, a screw conveyor is used for disassembling the material plugs and equalizing the feed rate, which is an effective solution. With this supply means, the material particles are supplied to the crusher in a relatively free state, and the crushing operation proceeds smoothly at all times. However, a disadvantage of this feeding means is that even the slightest disturbance in the feeding to the push pistons directly affects the amount of material fed into the grinding chamber, leading to disturbances in the grinding operation.

On the other hand, it has been found that conventional jet mills are not necessarily suitable for such mechanical feeding means, which themselves are very energy efficient. For this reason, new types of grinding devices have been devised, for example as shown in Finnish Patent No. 63869. The device comprises a pre-grinding chamber connected to each other by at least two Laval tubes,
The Laval tubes have an angle with each other, and a collision is formed between them, and in the collision area, the substance-gas mixture flow ejected from the Laval tubes collides with each other, and furthermore, from the classifier installed at the outlet side of the crusher. The configuration is such that the set of particles is returned directly to the collision zone. For perfect operation of such a device, it is necessary that even the particles in the substance-gas mixture reach supersonic velocities in the crushing nozzles of the device, and that the substance-gas mixture in each nozzle is equal and equal. The prerequisite is that the composition is the same.
However, in using this device, it has sometimes been difficult to maintain the material in a sufficiently fluid state within the pre-mill to distribute the material-gas mixture into equicompositional branch streams. Furthermore, it has also been difficult to supply the material to be crushed to the crushing device in an optimal state. If for some reason there is an imbalance in the flow in the grinding nozzle and the impact zone of the material particles deviates from the optimal position in the center of the main grinding chamber, severe wear and tear will occur on the walls of the main grinding chamber.

[Problem to be solved by the invention]

The object of this invention is to eliminate all of the above drawbacks,
The aim is to save as much energy as possible in jet grinding technology and to achieve a highly controlled and good grinding action in the grinding zone of the equipment.

[Means to solve the problem]

In order to solve the problem, the device according to the present invention has the following configuration.

(a) at least one substantially horizontal plug pipe with a feeder funnel, the free end of which has a feeder funnel extending in the longitudinal direction of the plug pipe for compressing and feeding the material to be ground into the gas-tight plug; (a) A pressure equalizing tank with a plug pipe connected to the top; (c) A pressure cylinder installed across the bottom of the pressure equalizing tank, the outlet end of which is connected to the outlet pipe of the pressure equalizing tank. (d) a pre-miller connected to the outlet pipe, said pre-miller being equipped with substantially tangential comminution gas nozzles;

(E) A distribution device provided on the outlet side of the pre-pulverizer for dividing the substance-gas mixed flow from the pre-pulverizer into two branch streams of equal composition and equal quantity, and a desired number of equal-composition branches. (f) a main grinding chamber into which each branch stream is fed via a grinding nozzle; The nozzles are preferably in the shape of a bench lily tube, and are opposed to each other so as to form a substantially conical shape, so that a collision area of the substance-gas mixture flow appears in the center of the main grinding chamber. a classifier connected to the outlet of the grinding chamber, the coarse powder outlet of the classifier directly connected to the main grinding chamber;
The fine powder outlet is connected to a treated material collection container.

(h) a screw conveyor drive motor coupled to a control system for regulating the operating speed of the screw conveyor; (k) operated on the basis of pulses corresponding to intermediate pressure changes at the outlet side of the crusher; A rotating body with radial wings is provided surrounding the Yukon conveyor.

[Effect]

The material to be crushed is consolidated through a plug pipe and sent to a pressure equalization tank for temporary storage. A screw conveyor then feeds the agglomerated material within the plug into a pre-mill. A pre-comminuted gas nozzle is provided, from which the substance-gas mixture stream is fed into a distribution device where it is divided into the desired number of equicompositionally branched mixture streams. The streams of equal composition thus divided are fed into the main grinding chamber via the grinding nozzles, and at this time grinding is carried out efficiently at the virtual intersection of the grinding nozzles.

More detailed functions and effects of the present invention will be described with reference to the drawings and explanations of embodiments.

〔Example〕

Next, embodiments of the invention will be described with reference to the drawings. The pressure chamber crushing device of the present invention comprises one or several plug pipes 1 which are substantially horizontal,
This plug pipe 1 is provided with a feeder funnel. At the free end of the plug pipe 1 there is a push cylinder 2 which operates in the longitudinal direction of the plug pipe 1.
is provided, and the push cylinder 2 compresses the material to be pulverized into an airtight plug and then supplies it to the upper part of the pressure equalization tank 3. The plug of material thus compressed and possibly partly agglomerated descends into the pressure equalization tank 3 and is intermediately stored in the tank 3 in at least a partially broken state. A screw conveyor 4 is installed below and across the pressure equalizing tank 3, and the outlet end of the screw conveyor 4 serves as an outlet pipe 5 of the pressure equalizing tank 3. The screw conveyor 4 breaks down the lumps inside the plug,
A uniform flow of material is fed into a pre-pulverizer 6 connected to the outlet pipe 5 of the pressure equalization tank 3. A plurality of substantially tangential grinding gas nozzles 7 are arranged in the pre-pulverizer 6 . Since the screw conveyor 4 is not required to operate against pressure resistance, the free state of the material is maintained when it is fed into the chamber of the pre-mill 6. The material fed into the pre-pulverizer 6 is mixed with high-pressure superheated grinding gas fed through tangential grinding gas nozzles 7 and is ground to some extent. On the outlet side of the pre-pulverizer 6, there is provided a device for dividing the substance-gas mixed flow into two branched flows of equal amount and composition. It is further divided by several distributors 8 to form a desired number of equicompositionally branched mixed streams. Each equicompositional stream thus divided is fed individually into the main comminution chamber 9 via a corresponding comminution nozzle 10, preferably in the form of a bench-lily tube. These pulverizing nozzles 10 are inserted into the main pulverizing chamber 9 so that the pulverizing nozzles 10 face each other and draw a conical shape. - an impingement zone of the gas mixture stream is created, in which efficient comminution takes place; By branching the substance-gas mixture stream into equicompositional streams with high precision, it is ensured that the substance-gas mixture stream ejected from each nozzle has a uniform velocity and a uniform composition. For this reason, particles collide efficiently and reliably within a very narrow area. A classifier 11 is connected to the outlet 12 of the main crushing chamber 9,
The coarse powder outlet of the classifier 11 is directly connected to the main crushing chamber 9, and the fine powder outlet is connected to a treated material collection container (not shown).

[Another example]

It is advantageous to provide this device with two plug pipes 1 with a common feeder funnel.
The feeder funnel is provided with a rotary gate, which closes the supply port of the plug pipe 1 on which the push cylinder 2 is pushing and returning, and at the same time closes the supply port of the plug pipe 1 in front of the push cylinder 2 of the other plug pipe 1. configured to supply a substance. When the former push cylinder 2 has finished its feeding operation, the gate is rotated to the other side and the material fed there is simultaneously precompressed.

In order to adjust the material supply so that there is always a suitable amount of material to be processed in the pre-mill 6, it is desirable to connect the drive motor 21 of the screw conveyor 4 to a control system to adjust its operating speed. This control system operates on the basis of pulses corresponding to intermediate pressure changes in the pre-mill 6 under the condition that the inlet pressure of the grinding gas is constant. The intermediate pressure depends on the amount of material fed to the pre-mill 6.

Since a very high starting pressure is used in this device, a very high compressive force acts on the material supplied to the pressure equalization tank 3 to form it into an airtight plug.
The plugged material is not sufficiently loosened by the disintegrating action of the screw conveyor 4 alone. Therefore, it is desirable to install the rotating body 14 within the pressure equalizing tank 3. The rotating body 14 is attached to the shaft of the screw conveyor 4 so as to surround the main body of the screw conveyor 4.

The grinding nozzle 10 is in the shape of a bench lily tube, and its length is selected depending on the particle size of the material to be ground, and the larger the particle size, the longer it is preferable. From the viewpoint of manufacturing and maintenance, it is desirable to have a configuration in which, for example, the nozzle consists of three parts, with two halves forming a conical part and a third part forming a conical part.

In order to ensure sufficient circulation between the grinding chamber 9 and the classifier 11, it is preferable to use a grinding chamber 9 in the form of a bench lily tube. In this case, the grinding nozzle 10 projects into the narrow space of the grinding chamber 9, and a material impingement zone appears there.

A very powerful push cylinder 2 is required to consolidate the material to be ground into a gas-tight plug. In order to increase the operating efficiency of the push cylinder 2, it is desirable to consolidate the material in multiple stages. This is achieved, for example, by providing an auxiliary push cylinder 15 operating in the inclined pipe connecting the feeder funnel and the plug pipe. The function of the auxiliary push cylinder 15 is to preconsolidate the material. If necessary, install a pipelator in the feeder funnel to remove air from the material,
It may be configured to consolidate the material to some extent.

In order to facilitate the circulation of the substance-gas flow between the grinding chamber 9 and the classifier 11, a blower 16 may be provided in the pipeline connecting the outlet of the grinding chamber 9 to the classifier 11.

For some materials it may be advantageous to carry out three stages of comminution. In this case, an intermediate grinder 1 with a substance-gas flow distributor 17 between the pre-pulverizer 6 and the main grinding chamber 9
9 can be provided. It is desirable to provide an intermediate superheater 20 on the outlet side of the intermediate crusher 19 so that the crushing gas contains sufficient energy even after this crushing step. The intermediate grinder 19 can also be provided with mutually opposed grinding nozzles 18, for example.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional plan view showing one embodiment of the present invention, Fig. 2 is an enlarged longitudinal sectional view of the main grinding chamber, Fig. 3 is a side view of the main grinding chamber and classifier, and Fig. 4 is a material- FIG. 2 is a detailed view of a device for dividing a gas mixture into two parts, in which A shows a cutout side surface of the side end thereof, and B shows a cross section taken along the line A-A. 1...Plug pipe, 2...Push cylinder, 3
... Equalization tank, 4 ... Screw conveyor, 5
... Outlet pipe, 6 ... Pre-pulverizer, 7 ... Grinding gas nozzle, 8 ... Distribution device, 9 ... Main grinding chamber, 10
... Grinding nozzle, 11 ... Classifier, 12 ... Main grinding chamber outlet, 13 ... Drive motor, 14 ... Rotating body, 15 ... Consolidation cylinder, 16 ... Blower,
17...Distributor, 18...Crushing nozzle, 19...
Intermediate crusher, 20...intermediate superheater.

Claims (1)

[Scope of Claims] 1. A pressure chamber pulverizing device for pulverizing a granular material into ultra-fine powder by colliding a pulverizing gas-material mixture jet with each other using high starting pressure and temperature, which has the following configuration: A device characterized by having the following. (a) at least one substantially horizontal plug pipe 1 provided with a feeder funnel; at the free end of the plug pipe 1 there is a plug pipe 1 for supplying the material to be crushed in a compressed manner to an airtight plug; A push cylinder 2 that operates in the longitudinal direction is provided, (a) a pressure equalization tank 3 connected to the plug pipe 1, (c) installed at the bottom of the pressure equalization tank 3, and its outlet end is connected to the pressure equalization tank 3. The screw conveyor 4 has an outlet pipe 5 , said outlet pipe 5 surrounding the screw conveyor 4 . (D) A pre-pulverizer 6 connected to the outlet pipe 5, in which a substantially tangential grinding gas nozzle 7 is disposed; (E) From the pre-pulverizer 6; (f) at least one distribution device 8 provided on the outlet side of the pre-pulverizer 6 for dividing the substance-gas mixture stream into two branch streams of equal volume and composition; The main grinding chamber 9 and the nozzle 10 that are fed through the main grinding chamber 9 face each other so as to substantially form a conical shape, and a collision zone of the substance-gas mixed flow appears in the center of the main grinding chamber 9. (g) A classifier 11 connected to the outlet 12 of the main crushing chamber 9, the coarse powder outlet of the classifier 11 is connected to the outlet 12 of the main crushing chamber 9.
(h) a screw conveyor drive motor 13 connected to a control system for regulating the operating speed of the screw conveyor 4; said control system operates on the basis of pulses corresponding to intermediate pressure changes on the outlet side of the pre-pulverizer 6 under the condition that the inlet pressure of the grinding gas is constant; A screw conveyor 4 is used to break down and loosen the supplied plug-like material.
A rotating body 14 with radial wings is provided, which is attached to the shaft of the screw conveyor 4 and surrounds the screw conveyor 4. 2. The main crushing chamber 9 is in the shape of a bench lily tube, and the crushing nozzle 10 is located at the narrow end of the tube, and a collision area is exposed there. Device. 3 Consolidation cylinder 15 that operates within the inclined pipe connecting the feeder funnel and plug pipe 1
3. Apparatus according to claim 2, characterized in that the material to be pulverized is formed into an airtight plug and the consolidation step is carried out in several stages. 4 A blower 1 is installed in the pipeline between the outlet of the main crushing chamber 9 and the classifier 11 to promote circulation of the material.
6. Device according to claim 2 or 3, characterized in that: 6 is provided. 5 Between the pre-pulverizer 6 and the main grinding chamber 9 an intermediate grinder 19 with a substance-gas flow distributor 17 and mutually opposed grinding nozzles 18 is provided, and on the outlet side of the intermediate grinder an intermediate heater 20 is provided. The device according to claim 4, characterized in that it is provided with:.