JPH0356785B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a grinding system, ie, a sealed closed circuit type grinding apparatus, which is composed of a ball mill, a classification cyclone, a back filter device, a blower device, and the like.

[Prior Art] A ball mill as a device for pulverizing a sample is well known in the art without citing literature as an example.
Similarly, classification cyclones and filter devices
Furthermore, blower devices are also well known in the art. These devices can therefore also be used to grind the sample, classify it, and recover the product.

However, when attempting to obtain ultrafine powder such as zirconia, the above-mentioned conventional apparatus has a problem. In other words, powders generally tend to agglomerate when they become ultra-fine, and agglomeration is particularly promoted when moisture (e.g., water vapor in the air) is mixed in. When agglomeration occurs, its core gradually grows and aggregates. Grinding and classification becomes difficult.

Therefore, it becomes virtually impossible to obtain powder with a size of 3μ or less. Another problem is that conventional equipment cannot perform continuous automatic operations such as crushing and classification.

In order to solve this problem, the applicant has
- In Publication No. 241942, a ball mill is configured to pulverize a sample while the sample is being supplied and discharged, a cyclone for classifying the sample pulverized by the ball mill, and a cyclone for classifying the sample pulverized by the ball mill. A back filter device for collecting products, a classification hopper device for supplying the coarse particles classified by the classification cyclone to the ball mill, and a classification hopper device for pumping the sample crushed by the ball mill to the classification cyclone. a blower device; a discharge port of the blower device;
The supply port of the classification cyclone is airtightly connected to a high-pressure pipe equipped with an injection nozzle, the outlet of the classification cyclone and the back-filter device are air-tightly connected to each other by a product pipe, and the exhaust port of the back-filter and the suction port of the blower device is airtightly connected by a return pipe, the discharge pipe of the ball mill is connected to the opening of the injection nozzle,
The classification hopper device is airtightly connected to the discharge port of the classification cyclone and the supply port of the ball mill, and the classification hopper device consists of a plurality of stages of hoppers. The present invention provides a sealed closed circuit type crushing device that can be operated at equal pressure by high pressure supplied from an equal pressure pipe connected to the pipe.

However, with this device, there is a problem that the powder and air separate after the injection nozzle part of the high-pressure pipe, and the powder adheres and aggregates inside the high-pressure pipe.
Further, the isobaric device of the classification hopper device is complicated in structure and operation.

[Object of the Invention] Accordingly, an object of the present invention is to provide a sealed closed circuit type crushing device that prevents powder from adhering and agglomerating inside a mixing tube, and which simplifies the structure and operation of the classification hopper device. .

[Configuration of the Invention] The sealed closed circuit type crushing device according to the present invention includes a ball mill configured to crush a sample while the sample is supplied and discharged, and a ball mill that classifies the sample crushed by the ball mill. a cyclone, a back filter device that collects the products classified by the classification cyclone, a classification hopper device configured to supply the coarse particles classified by the classification cyclone to the ball mill, and a product crushed by the ball mill. It consists of a blower device for force-feeding the sample to the classification cyclone, and the discharge port of the blower device and the supply port of the classification cyclone are airtightly connected by a high-pressure pipe equipped with an injection nozzle. The outlet of the cyclone and the back filter device are hermetically connected by a product pipe, the exhaust port of the back filter and the suction port of the blower device are hermetically connected by a return pipe, and the discharge pipe of the ball mill is connected hermetically by a product pipe. The classification hopper device is open to the injection nozzle, and is airtightly connected to the discharge port of the classification cyclone and the supply port of the ball mill, and the high-pressure pipe has a bend bent at an obtuse angle with respect to the discharge pipe of the ball mill. A mixing tube having a straight section and a straight section several times the diameter of the pipe, an injection nozzle section, an appropriate number of obtuse-angled bent sections, and a straight section continuous to the bent sections are formed.

[Operation of the invention] Therefore, when a sample is put into the ball mill, the mill is operated, and the blower device is started, the powder pulverized by the ball mill is sucked together with air into the injection nozzle and reaches the classification cyclone. The fine powder, that is, the product classified by the classification cyclone, reaches the back filter device through the product pipe.
It is collected here. The air or inert gas from which the product is recovered by the back filter device is sucked into the blower device and reused for pumping and classifying the powder. On the other hand, the coarse particles classified by the classification cyclone are temporarily stored in a classification hopper device and then supplied to a ball mill. In this way, the gas for conveyance and classification circulates through the blower device, high-pressure pipe, classification cyclone, back filter device, return pipe, etc., to the blower device, and the crushed material, or product, is collected by the back filter device and becomes coarse particles. will be circulated through a ball mill, a classification cyclone, a classification hopper device, and a ball mill. During circulation, sharp bends in the mixing tube cause centrifugal force to be expressed as velocity squared divided by radius of curvature (V ² /R), so increased centrifugal force promotes separation of powder and air and causes agglomeration. Therefore, the polygonal obtuse angle increases the curvature, which causes deterioration of the centrifugal force, while the straight part promotes the mixing of air and powder, and as a result, prevents the powder from adhering to the high pressure pipe and agglomerating. can do. In addition, by operating the upper and lower two-stage rotary valves, it is easy to input raw materials and feed coarse particles classified by the classification cyclone to the ball mill, thereby simplifying the structure and operation of the classification hopper device. I can do it.

[Preferred Embodiment] When carrying out the present invention, it is preferable that the bent portion of the high-pressure pipe be formed at 120 degrees to 150 degrees. In this way, it is possible to reduce the large centrifugal force that is applied to the mixed flow of powder and air, thereby preventing separation of the particles and air. Note that the straight portion is preferably 5 times or more the diameter of the tube. Further, as the ball mill, it is preferable to use an electromagnetic ball mill proposed by the present applicant (see Japanese Patent Application Laid-open No. 59-160543 and Japanese Patent Application Laid-open No. 59-160544). A conventionally known classification cyclone may be used, but a hopper having a ball valve or a rotary valve below may be used as the classification hopper device.

The back filter device is implemented as a box body for reducing the flight speed of the product to allow it to fall naturally, and a back filter box connected to the box body, and the blower device is implemented as a Roots blower.

[Example] An example of the present invention will be described below with reference to the accompanying drawings.

Now, referring to the drawings, a crushing apparatus M embodying the present invention includes a ball mill 1 and a classification cyclone 20.
, the back filter device 30, the Roots blower 40, the classification hopper device 50, and the lines that airtightly connect these devices, that is, piping A, B,
It is roughly composed of C, D, E, etc.

A ball mill or an electromagnetic ball mill 1 consists of a hollow cylindrical body 3 in which balls 2, 2... and a sample are housed and rotated, and the cylindrical body 3 is supported by hollow shafts 4, 4. 4 is pivotally supported by a pair of ball bearings 5, 5. One end of the hollow shafts 4, 4 opens into the cylindrical body 3, and inside thereof, a supply pipe 7 and a discharge pipe 8 are respectively fixed to a classification hopper device 50 and a high-pressure pipe B, which will be described later, via bearings 6 to 6. It is contained. Therefore, even when the cylindrical body 3 is driven to rotate, the sample is supplied into the cylindrical body 3 through the supply pipe 7, and the pulverized sample is discharged or supplied to the mixing pipe B via the discharge pipe 8. can do. The electromagnetic ball mill 1 is described in detail in the above-mentioned Japanese Patent Application Laid-Open No. 59-160543 and Japanese Patent Application Laid-Open No. 59-160544, and its structure is not directly related to the gist of the present invention.
I will briefly explain. Electromagnets 11, 11 are provided outside the cylindrical body 3 and are activated by supplying power from the non-contact relay 10, and during operation, these electromagnets 11, 11 lift the balls 2, 2... to the appropriate position and then release them. Thus, the grinding efficiency can be improved. Note that 12 is a fixed scraper fixed to the supply pipe 7 and the discharge pipe 8.

The Roots blower 40 is a pump having a discharge pressure of about 0.4 kg/cm ² G, and a reserve tank 41 and an injection nozzle 42 are interposed in its discharge line, that is, a high pressure pipe B. The high-pressure pipe B enters the classification cyclone 20 at a gas velocity of about 20 m/sec. The injection nozzle 42 has a known ejector section in which the pressure drops. The tip of the discharge pipe 8 of the ball mill 1 opens at the part where the pressure of the injection nozzle drops. Therefore, the branch line D is connected to the inside of the ball mill 1, and the pressurized air is supplied to the supply pipe 7.
It is connected to and is pressurized. Therefore, when the high-pressure gas flows through the injection nozzle portion N, the sample is sucked and pumped from the ball mill 1 and then supplied to the classification cyclone 20. This branch line D is provided with a regulating valve V. Nozzle part N
In order to increase the suction force of
It is necessary to adjust using the regulating valve V to raise the temperature by Kg/cm ² G to 0.6 Kg/cm ² G.

The injection nozzle portion N of the high pressure pipe B has an obtuse angle with respect to the discharge pipe 8, for example, preferably 120 degrees to 150 degrees.
A first bent part B11 bent at 135 degrees and a first straight part B21 having a length of six times or more the inner diameter of the mixing tube are formed, and the injection nozzle part N and the classifying cyclone 20 are connected to each other. In between, second and third bent portions B12, B13 preferably bent at 135 degrees and second and third straight portions B2 continuous therewith are provided.
2 and B23 are formed. The classification cyclone 20 includes a plurality of (two in the illustrated example) first
A cyclone 21 and a second cyclone 22 are arranged in series, and the second cyclone 22 is connected to a high-pressure pipe D via a branch pipe E, and receives a supply of high-pressure secondary air to generate air due to the resistance of the first cyclone 21. It is designed to accelerate the reduced flow velocity. This method can also be used to locally increase the speed and sharpen the classification since the centrifugal force is reduced when the diameter of the first cyclone increases due to its capacity. This first cyclone 21 is conventionally well known, but by providing a second cyclone 22, submicron powder of a medium size, for example, 0.5 to 0.6 μm, is sent to a back filter device 30 through a product pipe C, and a coarse powder is sent to the back filter device 30. The grains are discharged into a classification hopper device 50.

Intermediate particles, for example particles with a diameter of 0.85 μm, are collected in the hopper of the second cyclone 22. The back filter device 30 consists of a box 31 whose diameter is extremely large compared to the inner diameter of the product tube C, and a box 32 that is pneumatically connected above the box 31 in order to reduce the flying distance of the product. And the filter 33 attached to the box 32 is connected. A lid (not shown) is provided on the box 31 via a gasket so that it can be opened and closed freely.
2 is also provided with a lid so that the product inside can be collected or the filter 33 can be replaced. As described above, the diameter of the box 31 is sufficiently large, so that although the product is a fine powder, it is deposited inside the box due to gravity. Therefore, less product reaches the filter 33 and there is less chance of clogging the filter. Also, as shown, since the filter 33 is open at the bottom and the bottom or filter portion is at the top, the chance of clogging is also reduced by this arrangement. Moreover, an even more effective effect can be obtained by providing an electrostatic precipitator in the front space of the box.

A return pipe A extends from the bottom of the box 32 of the back filter device 30 and is pneumatically connected to an inlet 43 of the Roots blower 40. Therefore, the roots blower 40, high pressure pipe B, classification cyclone 20, product pipe C, bag filter device 30, and return pipe A constitute a pneumatically closed circuit.

Although the closed circuit is airtight, the amount of gas in the circuit increases and decreases during operation. Therefore, some kind of countermeasure is required. In this embodiment, a breather valve 44 is provided in the return pipe A for this purpose. The breather valve 44 releases and replenishes the gas in the return pipe A, and operates at, for example, about ±25 mmAg with respect to the pressure during normal operation.
The breather valve 44 is connected by a pipe 49 via a filter 47 to prevent foreign matter from entering the drying box 45 containing the desiccant 46.
The gas or air supply to the return pipe A is such that dry, clean air is supplied.

The classification hopper device 50 supplies the coarse particles classified by the classification cyclone 20 to the ball mill 1, and is configured as follows. That is, the hopper device 50 consists of a first hopper 51 located above and a second hopper 52 located below.
The first hopper 51 is formed integrally with the lower part of the first cyclone 21, and the second hopper 52 has a cylindrical part 53 that receives coarse particles, and a conical part connected to this part and whose diameter gradually decreases downward. The conical portion constitutes a discharge end, and a rotary breaker 55 for preventing powder clogging is provided near this conical portion. Each hopper 51, 52 is provided with upper and lower rotary valves 56a and 56b having dimensions and rotational speed matching the discharge amount,
Between these rotary valves, that is, a part of the part where the influence of the pressure from the upper classification cyclone 20 is weakened and also protected from the pressure from the lower rotary breaker 55 side, such as the cylindrical part 53, has a screw tube. Raw material input hopper 5 via Ida 57
8 is provided. The coarse particles from the second hopper 52 are supplied to the ball mill 1 by a screw feeder 13 installed in the supply pipe 7 via a lower rotary valve 56b and a rotary breaker 55. Therefore, if the raw material is received into the cylindrical portion 53 while rotating both rotary valves 56a and 56b when inputting the raw material, the raw material is supplied to the rotary breaker 55 from the lower rotary valve 56b while maintaining a sufficiently low pressure (for example, ±10 mmAg). be able to.

Therefore, according to the present invention, since the ball mill, classification cyclone, back filter device, blower device and classification hopper device constitute a closed circuit,
This prevents water vapor, foreign matter, etc. from entering the circuit. Therefore, the powder to be crushed or the crushed product will not be agglomerated due to moisture, and no foreign matter will be mixed into the product, thereby reducing the quality of the product. In addition, the bent portions B11, B12, and B13 of the high-pressure pipe B reduce the large centrifugal force on the mixed flow of powder and air to prevent separation of the particles and air, and the straight portions B21, B
22 and B23 promote mixing of air and granules;
As a result, adhesion and aggregation of powder to the high-pressure pipe is prevented. In this manner, the obtuse-angled bent portion causes turbulence in the flow of the polygonal tube, and its separation effect prevents agglomeration. Further, by operating the upper and lower rotary valves 56a and 56b, raw materials can be input and coarse particles classified by the classification cyclone 20 can be supplied to the ball mill 1. Note that the present invention is not limited to the above embodiments,
It can be implemented in various ways. For example, instead of the breather valve 44, a pressure sensor can be provided at an appropriate location in the piping, and the amount of gas in the system can be controlled by this sensor. In addition, a classification cyclone, back filter device, etc. are installed in parallel for one ball mill.
By appropriately switching these, continuous operation can be performed without support. It is also possible to suppress the temperature rise within the circuit by providing a cooler at an appropriate location in the closed circuit.

[Summary] As explained above, according to the present invention, the high-pressure pipe includes a high-pressure pipe that is a mixing pipe having a bent part bent at an obtuse angle with respect to the discharge pipe of the ball mill, and a straight part, an injection nozzle part, and an appropriate number of pipes. Since an obtuse bent part and a straight part continuous to the bent part are formed, separation of particles and air in the high pressure pipe is suppressed, and adhesion and agglomeration of powder on the high pressure pipe is prevented. .
Furthermore, since the high pressure supply to the classification hopper device in the conventional device is eliminated, the structure and operation of the classification hopper device are simplified.

[Brief explanation of drawings]

The drawings are overall explanatory diagrams showing one embodiment of the present invention. 1... Ball mill (electromagnetic ball mill), 7...
Supply pipe, 8... Discharge pipe, 20... Classifying cyclone, 30... Back filter device, 33... Filter, 40... Vortex pump, 41... Reserve tank, 42... Injection nozzle, 44... Breather valve, 45... Drying box, 50... Classifying hopper device, 54... Conical part of hopper (discharge end), 55... Small cone, 58, 59... Equal pressure tube,
A... Return pipe, B... High pressure pipe, C... Product pipe, D... High pressure main pipe, B11, B12, B13...
...Bending part, B21, B22, B23... Straight part,
C...product pipe, D...branch pipe, E...branch pipe, N...nozzle part of high pressure pipe.

Claims (1)

[Claims] 1. A ball mill adapted to pulverize a sample while it is fed and discharged;
a cyclone for classifying the sample crushed by the ball mill; a back filter device for collecting the product classified by the classification cyclone; and a classifier for supplying the coarse particles classified by the classification cyclone to the ball mill. It consists of a hopper device and a blower device for force-feeding the sample crushed by the ball mill to the classification cyclone, and the discharge port of the blower device and the supply port of the classification cyclone are connected to a high pressure injector equipped with an injection nozzle. The outlet of the classification cyclone and the back-filter device are air-tightly connected by a product pipe, and the exhaust port of the back-filter device and the inlet of the blower device are air-tightly connected by a return pipe. The discharge pipe of the ball mill opens to the injection nozzle, the classification hopper device is airtightly connected to the discharge port of the classification cyclone and the supply port of the ball mill, and the discharge pipe of the ball mill opens to the injection nozzle. and the injection nozzle are connected at an obtuse angle, and the injection nozzle is connected at an obtuse angle to a straight part of the high-pressure pipe, and the straight part of the high-pressure pipe is connected to another straight part of the high-pressure pipe through an obtuse bent part. A sealed closed circuit type crushing device characterized by being connected to. 2. The sealed closed circuit type crushing device according to claim 1, wherein a breather valve is interposed in the return pipe. 3. The sealed closed circuit crushing device according to claim 2, wherein the intake side of the breather valve is connected to a drying box. 4. The classification hopper device consists of two stages of hoppers, these hoppers are connected by two stages of upper and lower rotary valves, and these rotary valves are operated with dimensions and rotational speed that match the discharge amount,
The sealed closed circuit type crushing apparatus according to any one of claims 1 to 3, wherein a raw material inlet is provided in a portion where upper and lower pressures are cut off by these rotary valves. 5. The sealed closed circuit according to claim 4, wherein the hopper has a downwardly reduced diameter portion near the discharge end, and this portion is provided with a rotating breaker for preventing powder clogging. Shape crushing equipment. 6. The sealed closed circuit crushing device according to claim 1, wherein a reserve tank is interposed in the high-pressure pipe, and one end of the high-pressure pipe is open to the reserve tank. 7. The sealed closed circuit type crushing according to claim 1, wherein the classification cyclone is provided with a plurality of cyclones arranged in series, and a branch pipe of a high-pressure pipe is connected to the cyclone whose flow rate decreases. Device. 8. The sealed closed circuit type crushing device according to claim 1, wherein a high pressure pipe is connected to the supply port of the ball mill. 9. The sealed closed circuit type according to any one of claims 1 to 8, wherein a pressure sensor is provided in the return pipe, and the pressure in the return pipe is controlled by the sensor. Grinding equipment. 10 The wind speed at the entrance of the classification cyclone is approximately 20 m/sec
A sealed closed circuit type crushing device according to any one of claims 1 to 9.