CA1261309B - Method of finely crushing particles of material in a centrifigual mill and apparatus for performing the method - Google Patents
Method of finely crushing particles of material in a centrifigual mill and apparatus for performing the methodInfo
- Publication number
- CA1261309B CA1261309B CA000589704A CA589704A CA1261309B CA 1261309 B CA1261309 B CA 1261309B CA 000589704 A CA000589704 A CA 000589704A CA 589704 A CA589704 A CA 589704A CA 1261309 B CA1261309 B CA 1261309B
- Authority
- CA
- Canada
- Prior art keywords
- impact
- particles
- rotor
- impact surface
- path
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
- B02C13/14—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices
- B02C13/18—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor
- B02C13/1807—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor the material to be crushed being thrown against an anvil or impact plate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
- B02C13/14—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices
- B02C13/18—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor
- B02C13/1807—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor the material to be crushed being thrown against an anvil or impact plate
- B02C13/1814—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor the material to be crushed being thrown against an anvil or impact plate by means of beater or impeller elements fixed on top of a disc type rotor
Landscapes
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Crushing And Pulverization Processes (AREA)
- Crushing And Grinding (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method of comminuting particles of material in a centrifugal mill or the like having a vacuum chamber, comprises rotating at least one rotor carrying at least one impact surface such that the impact surface travels in a closed path in the vacuum chamber, feeding the particles into the vacuum chamber at the impact position such that when the impact surface passes through the impact position, it strikes the particles with sufficient energy to break them into fragments, the fragments then being propelled centrifugally for further fragmentation against stationary impact surfaces outside the closed path.
A method of comminuting particles of material in a centrifugal mill or the like having a vacuum chamber, comprises rotating at least one rotor carrying at least one impact surface such that the impact surface travels in a closed path in the vacuum chamber, feeding the particles into the vacuum chamber at the impact position such that when the impact surface passes through the impact position, it strikes the particles with sufficient energy to break them into fragments, the fragments then being propelled centrifugally for further fragmentation against stationary impact surfaces outside the closed path.
Description
~ X613~
The present invention relates to a method and apparatus for finely crushing or comminuting particles of material in a centrifugal mill or the like, wherein at least one rotor projects the particles against stationary impact surfaces in the mill, the comminution taking plac~ substantially in vacuum.
Mechanical comminution of solid particles may be classified according to the manner of operation of the apparatus that performs the crushing. Crushing or milling may be performed according to two main principles either with pressure that ruptures the particles, as for instance by means of jaw crushers, pendulum mills, tower mills, roller mills and the like, or with kinetic energy that causes fragmentation or bursting of the particles. Typical examples of the latter category are hammer mills, pin mills and jet mills.
There is a great demand on the market for finely crushed material especially in the filler industry as fillers e.g. in plastics and paper industry. Another large product area is finely milled quartz and feldspar for the ceramic industry.
Todays technology for producing fine grained materials are very energy and cost demanding, especially when narrow tolerances in grain size and particle sizes below 30 microns are desired. Sizes down to 45 microns may be obtained with ball mills, but since the grinding balls usually consist of iron it is not possible to obtain iron-free milling. This type of milling therefore is not useable for materials which are to be used as whitening agents in the paper and plastic industries, since even small proportions of iron destroys the whiteness. In order to arrive at particle sizes of 20 microns, either conventional milling and air stream separation or a jet mill is used. The problem with air-separated material is that too much of too coarse fractions will be included, which is mostly not acceptable. With jet mills it is possible to arrive at particle sizes around 10 microns and even smaller but the jet mill has a low ~¢
~6~0~
efficiency and a very high energy consumption (350-7--kWh/ton).
The amount of energy consumed in crushing by means of kinetic energy or impact energy may be divided into three main groups, viz. energy which is consumed for elastic deformation of the grains or particles and which is lost, supplied energy which bursts the grains, and energy for the operation of surrounding equipment etc~ At low velocities, a substantial portion of the supplied energy will be used up for the elastic deformation of the particles, which gives a low efficiency. Furthermore, the elastic deformation will cause the particles to bounce instead of bursting, which will cause heavy wear. At high velocities, on the other hand, the energy consumed for elastic deformation amounts only to a small portion of the total energy, whereas the high impact energy, if it can be applied as "instantaneously" as possible, gives very high stress concentrations and provides an efficient crushing. This means that a high particle velocity and instantaneous impact force should be chosen.
The jet mill which has proved to be especially suitable for crushing or milling into fractions with very small grains utilizes a high particle velocity and uses pressurized air for accelerating the grains to about 100 m/s, and the high velocity grains collide with other grains resulting in the grains bursting each other. However, due to the very high energy consumption per ton, low efficiency and very high production costs, the jet mill has so far only been used in "exclusive" connections, for instance in the chemical industry and the pharmaceutical industry.
It has also been suggested (German patent specification 387,995) to use disintegrators or stamp mills, the milling tools of which operate in an air-void space in order to obtain a fine grinding, preferably together with a dispersing agent.
~261~30~3 An object of the invention i5 to provide a comparatively simple method which, while involving a low energy consumption, may provide fractions with very small grains (below 10 mi~rons~. This object has been attained in that the particles are accelerated in vacuum to such a high impact energy against the impact surface or surfaces of the rotor that a first fragmentation takes place before the particles are projected against stationary impact surfaces of the mill.
Accordingly a first aspect of the invention provides a method of comminuting particles of material in a centrifugal mill or the like having a vacuum chamber, the method comprising rotating at least one rotor carrying at least one impact surface such that said impacted surface travels in a closed path in said vacuum chamber, and feeding the particles into said vacuum chamber at said impact position such that when said impact surface passes through said impact position, it strikes said particles with sufficient energy to break them into fragments, said fragments then being propelled centrifugally for further fragmentation against stationary impact surfaces outside said closed path.
A second aspect of the invention provides an apparatus for the comminution of particles of material in a centrifugal mill or the like, comprising: a vacuum chamber; at least one rotor in said chamber and having at least one impact surface projecting radially therefrom, said impact surface describing a closed path during rotation; at least one pact station in said closed path; stationary impact surfaces in said chamber outside said closed path; at least one accelerator feeding the particles to said impact station with a velocity sufficient to keep said impact station supplied with particles when said impact surface passes therethrough; means for rotating said rotor with sufficient speed to fragment the particles at said impact station due to the impact energy of said impact surface and propel the particle fragments centrifugally from said station against said stationary 3(~
impact surfaces for further fragmentation; and means for evacuating the comminuted particles from said housing.
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:-Fig. 1 is a diagrammatic section through a centrifugal mill according to the invention and intended for laboratory purposes;
Fig. 2 is a section taken on the line II-II in Fig. l;
Fig. 3 is a partly broken side view of a centrifugal mill with twin rotors according to another embodiment of the invention;
Fig. 4 is a section taken on the line IV-IV in Fig. 3; and Fig. 5 is a side view of a complete installation for the recirculation of the particles of material.
The centrifugal mill according to the invention consists of a housing 11 which may be sealed airtight and which contains a crushing chamber 12 wherein there is rotatably arranged a rotor 13 which is provided at each end with an impact surface 14. The rotor is journalled in a heavy bearing 15 and is driven by a motor 16 by means of a suitable transmission 17.
Opposite to the path of movement of the impact surfaces 14 there is provided at least one supply channel 18 through which particles of material that are to be finely divided are supplied intermittently. The opening 19 of the supply channel 18 in the housing 11 is provided at some distance from an impact surface 20 which is oriented in such a way that it extends substantially in parallel with the rotor impact surface 14 when this is disposed below the outlet opening 19. In the embodiment shown in Figs. 1 and 2, the impact surface 20 is disposed outside of the path of rotation of the impact surface 14. Any particles projected to the side of the impact surface 20 will be arrested by the following impact surfaces 20' and 20". Below the impact surfaces there is provided, in the bottom 21 of the crushing chamber, an outlet opening 22 through which the material ~L26~3~9 which has been projected against the impact surfaces 14 and 20 and crushed thereby leaves the crushing chamber 12. The outlet opening 22 may be connected to a recirculation system of the kind illustrated in Fig. 9 which returns the particles to the supplied channel 18. The outlet opening may also be connected to a feeding out device (not shown) for batchwise removal of the crushed material from the apparatus.
With the aid of a passive or active accelerator 28, the particles of material are supplied to the crushing chamber 12 and the rotor impact surface or surfaces 14 with such a velocity that the maximum amount of crushing material is supplied for each strike. The "passive" accelerator consists of a vertical tube 18 included in the air-void system and having such a length (for instance 3 m), that the desired velocity of the particles is obtained. The rotor's own velocity is so large that the particles will be fragmented a first time by this impact and a second time when they strike the stationary impact surfaces.
With the aid of a device not shown, a vacuum is maintained in the accelerator 28, the crushing chamber 12 and spaces communicating therewith, so that the crushing chamber is practically air-void (the air should be evacuated to at least 90%). Thanks to this arrangement the rotor 13 with the impact surfaces 14 will not provide any fan action, and interfering shock waves and uncontrolled turbulence is avoided. The particles instantaneously hit by the impact surface will be crushed by the impact against the surface and will be projected tangentially out of the path of movement of the rotor and against one or several stationary impact surfaces 20 where further crushing takes place. By means of a metering device 23 provided with a rotor 24 a suitable amount of particles of material is fed to the impact surfaces 14 synchronously with their passing of the outlet opening 19.
Practical tests with a laboratory mill has shown that it is feasible to give the rotor a peripheral velocity of 180 m/s.
~.~61;~()9 However, for commercial operation, the upper practical limit for the peripheral velocity of the rotor would probably be about 400 m/s. In ordsr to accelerate one ton of particles to a velocity of 180 m/s, 4,5 kWh are consumed, and at four circulations the theoretical energy consumption would be 36 Kwh/ton. To this is added the energy consumed for recirculation and for the operation of the vacuum pump.
since the crushing takes place in vacuum and at a high velocity of motion the losses will be moderate compared to current technology.
The embodiment of Figs. 3 and 4 differs from the above-described embodiment in two important respects: two or more rotors are arranged in parallel one above the other, and the particles are supplied to the first crushing chamber 12 with such a high kinetic energy (which, however, is only about 1/10 of the rotational energy of the impact surface) is obtained by means of an "active" accelerator 28 which, as an example, may consist of a centrifuge, the blades of which are preferably rubber coated in order to reduce wear.
In the centrifugal mill according to this embodiment the impact surfaces 20 are preferably oriented in such a way, that the particles will fall toward the next rotor 13a which i5 provided directly below and close to the rotor 13. In order to obtain a high capacity, a supply channel 18 is provided opposite to every other impact surface 20. The impact surfaces 20 have a V-shaped cross-section whereby it will be possible to utilize the second leg of the V by reversing the motor. In this embodiment the two crushing chambers 12 and 12a as well as the collecting chamber 26 and the metering accelerator 28 are connected to one and the same vacuum system.
Fig. 5 shows a recirculating devi~e for the centrifugal mill according to the invention and comprising two elevators 29 and 30, a silo 31 and a metering accelerator 28. In this ~26~t~
case a practically air-void condition is maintained in the complete installation by means of a pump 32 of the like.
The present invention relates to a method and apparatus for finely crushing or comminuting particles of material in a centrifugal mill or the like, wherein at least one rotor projects the particles against stationary impact surfaces in the mill, the comminution taking plac~ substantially in vacuum.
Mechanical comminution of solid particles may be classified according to the manner of operation of the apparatus that performs the crushing. Crushing or milling may be performed according to two main principles either with pressure that ruptures the particles, as for instance by means of jaw crushers, pendulum mills, tower mills, roller mills and the like, or with kinetic energy that causes fragmentation or bursting of the particles. Typical examples of the latter category are hammer mills, pin mills and jet mills.
There is a great demand on the market for finely crushed material especially in the filler industry as fillers e.g. in plastics and paper industry. Another large product area is finely milled quartz and feldspar for the ceramic industry.
Todays technology for producing fine grained materials are very energy and cost demanding, especially when narrow tolerances in grain size and particle sizes below 30 microns are desired. Sizes down to 45 microns may be obtained with ball mills, but since the grinding balls usually consist of iron it is not possible to obtain iron-free milling. This type of milling therefore is not useable for materials which are to be used as whitening agents in the paper and plastic industries, since even small proportions of iron destroys the whiteness. In order to arrive at particle sizes of 20 microns, either conventional milling and air stream separation or a jet mill is used. The problem with air-separated material is that too much of too coarse fractions will be included, which is mostly not acceptable. With jet mills it is possible to arrive at particle sizes around 10 microns and even smaller but the jet mill has a low ~¢
~6~0~
efficiency and a very high energy consumption (350-7--kWh/ton).
The amount of energy consumed in crushing by means of kinetic energy or impact energy may be divided into three main groups, viz. energy which is consumed for elastic deformation of the grains or particles and which is lost, supplied energy which bursts the grains, and energy for the operation of surrounding equipment etc~ At low velocities, a substantial portion of the supplied energy will be used up for the elastic deformation of the particles, which gives a low efficiency. Furthermore, the elastic deformation will cause the particles to bounce instead of bursting, which will cause heavy wear. At high velocities, on the other hand, the energy consumed for elastic deformation amounts only to a small portion of the total energy, whereas the high impact energy, if it can be applied as "instantaneously" as possible, gives very high stress concentrations and provides an efficient crushing. This means that a high particle velocity and instantaneous impact force should be chosen.
The jet mill which has proved to be especially suitable for crushing or milling into fractions with very small grains utilizes a high particle velocity and uses pressurized air for accelerating the grains to about 100 m/s, and the high velocity grains collide with other grains resulting in the grains bursting each other. However, due to the very high energy consumption per ton, low efficiency and very high production costs, the jet mill has so far only been used in "exclusive" connections, for instance in the chemical industry and the pharmaceutical industry.
It has also been suggested (German patent specification 387,995) to use disintegrators or stamp mills, the milling tools of which operate in an air-void space in order to obtain a fine grinding, preferably together with a dispersing agent.
~261~30~3 An object of the invention i5 to provide a comparatively simple method which, while involving a low energy consumption, may provide fractions with very small grains (below 10 mi~rons~. This object has been attained in that the particles are accelerated in vacuum to such a high impact energy against the impact surface or surfaces of the rotor that a first fragmentation takes place before the particles are projected against stationary impact surfaces of the mill.
Accordingly a first aspect of the invention provides a method of comminuting particles of material in a centrifugal mill or the like having a vacuum chamber, the method comprising rotating at least one rotor carrying at least one impact surface such that said impacted surface travels in a closed path in said vacuum chamber, and feeding the particles into said vacuum chamber at said impact position such that when said impact surface passes through said impact position, it strikes said particles with sufficient energy to break them into fragments, said fragments then being propelled centrifugally for further fragmentation against stationary impact surfaces outside said closed path.
A second aspect of the invention provides an apparatus for the comminution of particles of material in a centrifugal mill or the like, comprising: a vacuum chamber; at least one rotor in said chamber and having at least one impact surface projecting radially therefrom, said impact surface describing a closed path during rotation; at least one pact station in said closed path; stationary impact surfaces in said chamber outside said closed path; at least one accelerator feeding the particles to said impact station with a velocity sufficient to keep said impact station supplied with particles when said impact surface passes therethrough; means for rotating said rotor with sufficient speed to fragment the particles at said impact station due to the impact energy of said impact surface and propel the particle fragments centrifugally from said station against said stationary 3(~
impact surfaces for further fragmentation; and means for evacuating the comminuted particles from said housing.
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:-Fig. 1 is a diagrammatic section through a centrifugal mill according to the invention and intended for laboratory purposes;
Fig. 2 is a section taken on the line II-II in Fig. l;
Fig. 3 is a partly broken side view of a centrifugal mill with twin rotors according to another embodiment of the invention;
Fig. 4 is a section taken on the line IV-IV in Fig. 3; and Fig. 5 is a side view of a complete installation for the recirculation of the particles of material.
The centrifugal mill according to the invention consists of a housing 11 which may be sealed airtight and which contains a crushing chamber 12 wherein there is rotatably arranged a rotor 13 which is provided at each end with an impact surface 14. The rotor is journalled in a heavy bearing 15 and is driven by a motor 16 by means of a suitable transmission 17.
Opposite to the path of movement of the impact surfaces 14 there is provided at least one supply channel 18 through which particles of material that are to be finely divided are supplied intermittently. The opening 19 of the supply channel 18 in the housing 11 is provided at some distance from an impact surface 20 which is oriented in such a way that it extends substantially in parallel with the rotor impact surface 14 when this is disposed below the outlet opening 19. In the embodiment shown in Figs. 1 and 2, the impact surface 20 is disposed outside of the path of rotation of the impact surface 14. Any particles projected to the side of the impact surface 20 will be arrested by the following impact surfaces 20' and 20". Below the impact surfaces there is provided, in the bottom 21 of the crushing chamber, an outlet opening 22 through which the material ~L26~3~9 which has been projected against the impact surfaces 14 and 20 and crushed thereby leaves the crushing chamber 12. The outlet opening 22 may be connected to a recirculation system of the kind illustrated in Fig. 9 which returns the particles to the supplied channel 18. The outlet opening may also be connected to a feeding out device (not shown) for batchwise removal of the crushed material from the apparatus.
With the aid of a passive or active accelerator 28, the particles of material are supplied to the crushing chamber 12 and the rotor impact surface or surfaces 14 with such a velocity that the maximum amount of crushing material is supplied for each strike. The "passive" accelerator consists of a vertical tube 18 included in the air-void system and having such a length (for instance 3 m), that the desired velocity of the particles is obtained. The rotor's own velocity is so large that the particles will be fragmented a first time by this impact and a second time when they strike the stationary impact surfaces.
With the aid of a device not shown, a vacuum is maintained in the accelerator 28, the crushing chamber 12 and spaces communicating therewith, so that the crushing chamber is practically air-void (the air should be evacuated to at least 90%). Thanks to this arrangement the rotor 13 with the impact surfaces 14 will not provide any fan action, and interfering shock waves and uncontrolled turbulence is avoided. The particles instantaneously hit by the impact surface will be crushed by the impact against the surface and will be projected tangentially out of the path of movement of the rotor and against one or several stationary impact surfaces 20 where further crushing takes place. By means of a metering device 23 provided with a rotor 24 a suitable amount of particles of material is fed to the impact surfaces 14 synchronously with their passing of the outlet opening 19.
Practical tests with a laboratory mill has shown that it is feasible to give the rotor a peripheral velocity of 180 m/s.
~.~61;~()9 However, for commercial operation, the upper practical limit for the peripheral velocity of the rotor would probably be about 400 m/s. In ordsr to accelerate one ton of particles to a velocity of 180 m/s, 4,5 kWh are consumed, and at four circulations the theoretical energy consumption would be 36 Kwh/ton. To this is added the energy consumed for recirculation and for the operation of the vacuum pump.
since the crushing takes place in vacuum and at a high velocity of motion the losses will be moderate compared to current technology.
The embodiment of Figs. 3 and 4 differs from the above-described embodiment in two important respects: two or more rotors are arranged in parallel one above the other, and the particles are supplied to the first crushing chamber 12 with such a high kinetic energy (which, however, is only about 1/10 of the rotational energy of the impact surface) is obtained by means of an "active" accelerator 28 which, as an example, may consist of a centrifuge, the blades of which are preferably rubber coated in order to reduce wear.
In the centrifugal mill according to this embodiment the impact surfaces 20 are preferably oriented in such a way, that the particles will fall toward the next rotor 13a which i5 provided directly below and close to the rotor 13. In order to obtain a high capacity, a supply channel 18 is provided opposite to every other impact surface 20. The impact surfaces 20 have a V-shaped cross-section whereby it will be possible to utilize the second leg of the V by reversing the motor. In this embodiment the two crushing chambers 12 and 12a as well as the collecting chamber 26 and the metering accelerator 28 are connected to one and the same vacuum system.
Fig. 5 shows a recirculating devi~e for the centrifugal mill according to the invention and comprising two elevators 29 and 30, a silo 31 and a metering accelerator 28. In this ~26~t~
case a practically air-void condition is maintained in the complete installation by means of a pump 32 of the like.
Claims (13)
1. A method of comminuting particles of material in a centrifugal mill or the like having a vacuum chamber, the method comprising rotating at least one rotor carrying at least one impact surface such that said impact surface travels in a closed path in said vacuum chamber, and feeding the particles into said vacuum chamber at said impact position such that when said impact surface passes through said impact position, it strikes said particles with sufficient energy to break them into fragments, said fragments then being propelled centrifugally for further fragmentation against stationary impact surfaces outside said closed path.
2. A method as claimed in claim 1, wherein the particles are fed to the rotor from an accelerator in a measured amount and at a point where the rotor impact surface is substantially parallel with the nearest following stationary impact surface in the direction of rotation of the rotor.
3. A method as claimed in claim 1 or 2, wherein at least a portion of the particles, after passing through the centrifugal mill or the like, are returned in a vacuum via a transport system to the accelerator for further processing.
4. An apparatus for the comminution of particles of material in a centrifugal mill or the like, comprising: a vacuum chamber; at least one rotor in said chamber and having at least one impact surface projecting radially therefrom, said impact surface describing a closed path during rotation; at least one impact station in said closed path; stationary impact surfaces in said chamber outside said closed path; at least one accelerator feeding the particles to said impact station with a velocity sufficient to keep said impact station supplied with particles when said impact surface passes therethrough; means for rotating said rotor with sufficient speed to fragment the particles at said impact station due to the impact energy of said impact surface and propel the particle fragments centrifugally from said station against said stationary impact surfaces for further fragmentation; and means for evacuating the comminuted particles from said housing.
5. An apparatus as claimed in claim 4, wherein at least one dosing device is provided for controlling the supply of the material to at least one position above and opposite to the path of rotation of the rotor impact surface(s).
6. An apparatus as claimed in claim 4 or 5, wherein said accelerator is adapted, by means of externally supplied energy, to propel the particles with increased energy towards the impact station.
7. A method for producing pulverized materials by comminuting particles of the material comprising: rotating at least one substantially vertical impact surface located at the peripheral end of a rotor in a closed path about an upstanding axis; repeatedly moving said at least one impact surface through at least one impact position in said path at the peripheral end of said rotor; feeding the particles of material to be comminuted in an axial direction downwardly with respect to said rotor just opposite the peripheral end thereof to supply said at least one impact position with particles when said at least one vertical impact surface passes through said at least one impact position; evacuating and maintaining said path and said feeding and impact areas under a substantial vacuum; accelerating the particles in the vacuum during the feeding step downwardly towards said at least one impact position; impacting said accelerated particles in said at least one impact position with sufficient energy to crush them and produce fragments;
projecting the fragments by the impact surface against stationary, vertical impact surfaces outside said path to produce further crushing; and leading the comminuted particles downwardly out of said path immediately after said further crushing on said stationary impact surfaces.
projecting the fragments by the impact surface against stationary, vertical impact surfaces outside said path to produce further crushing; and leading the comminuted particles downwardly out of said path immediately after said further crushing on said stationary impact surfaces.
8. A method as claimed in claim 7 and further comprising:
simultaneously feeding said particles of material to said rotating impact surface at circumferentially spaced feeding positions with respect to the path of movement of said impact surface.
simultaneously feeding said particles of material to said rotating impact surface at circumferentially spaced feeding positions with respect to the path of movement of said impact surface.
9. An apparatus for producing pulverized materials by comminuting particles of the material in a mill, comprising:
a housing; a rotor rotatable in said housing about an upstanding axis; at least one substantially vertical impact surface at the peripheral end of said rotor describing a closed path in said housing of said rotor having at least one impact position; means for evacuating said path and the feeding and impact areas in said housing and maintaining a substantial vacuum; means for feeding and accelerating said particles in an axial direction downwardly with respect to said rotor at the peripheral end thereof with a velocity sufficient to keep said at least one impact position supplied with particles when said at least one impact surface passes said at least one position; means for rotating said rotor with sufficient speed to crush the particles in said at least one impact position by the impact energy of said at least one impact surface, said impact surface projecting the particle fragments therefrom; vertical stationary impact surfaces in said housing for further crushing the particle fragments projected from said at least one position; said stationary impact surfaces being oriented substantially parallel to said at least one rotor impact surface at said at least one impact position so that the particles projected by said rotor impact surface impact against said stationary impact surfaces substantially perpendicularly; and means for leading the particles downwardly out of said path immediately after said further crushing on said stationary impact surfaces.
a housing; a rotor rotatable in said housing about an upstanding axis; at least one substantially vertical impact surface at the peripheral end of said rotor describing a closed path in said housing of said rotor having at least one impact position; means for evacuating said path and the feeding and impact areas in said housing and maintaining a substantial vacuum; means for feeding and accelerating said particles in an axial direction downwardly with respect to said rotor at the peripheral end thereof with a velocity sufficient to keep said at least one impact position supplied with particles when said at least one impact surface passes said at least one position; means for rotating said rotor with sufficient speed to crush the particles in said at least one impact position by the impact energy of said at least one impact surface, said impact surface projecting the particle fragments therefrom; vertical stationary impact surfaces in said housing for further crushing the particle fragments projected from said at least one position; said stationary impact surfaces being oriented substantially parallel to said at least one rotor impact surface at said at least one impact position so that the particles projected by said rotor impact surface impact against said stationary impact surfaces substantially perpendicularly; and means for leading the particles downwardly out of said path immediately after said further crushing on said stationary impact surfaces.
10. The apparatus as claimed in claim 9 and further comprising: a particle accelerator incorporating an upstanding evacuated tube having a length sufficient to produce a free fall velocity implementing the crushing of the particles by said rotor impact surface.
11. The apparatus as claimed in claim 10 wherein said feeding means comprise: a plurality of said evacuated tubes circumferentially spaced so that the particles therefrom pass through the path of travel of said rotor impact surface.
12. The apparatus as claimed in claim 9 and further comprising: a particle accelerator incorporating an upstanding evacuated tube; a centrifuge device operatively connected to said evacuated tube; and means to drive said centrifuge at sufficient speed to project the particles through said tube with a velocity implementing the crushing of the particles at said rotor impact surface.
13. The apparatus as claimed in claim 12 wherein said particle accelerator comprises: a plurality of said evacuated tubes and centrifuge devices; and outlets for said tubes circumferentially spaced so that the particles therefrom pass through the path of travel of said at least one rotor impact surface.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE81-023434 | 1981-04-13 | ||
| SE8102343A SE432719B (en) | 1981-04-13 | 1981-04-13 | SET FOR FINE CROSS MATERIAL PARTICLES IN A CENTRIFUGAL CROSS AND APPLICATION FOR IMPLEMENTATION OF THE SET |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1261309B true CA1261309B (en) | 1989-09-26 |
Family
ID=20343579
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000400899A Expired CA1182089A (en) | 1981-04-13 | 1982-04-13 | Method of finely crushing particles of material in a centrifugal mill and apparatus for performing the method |
| CA000589704A Expired CA1261309B (en) | 1981-04-13 | 1989-01-31 | Method of finely crushing particles of material in a centrifigual mill and apparatus for performing the method |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000400899A Expired CA1182089A (en) | 1981-04-13 | 1982-04-13 | Method of finely crushing particles of material in a centrifugal mill and apparatus for performing the method |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0088762B1 (en) |
| JP (1) | JPS58500600A (en) |
| CA (2) | CA1182089A (en) |
| DE (1) | DE3265548D1 (en) |
| SE (1) | SE432719B (en) |
| WO (1) | WO1982003572A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2655880A1 (en) * | 1990-01-31 | 1991-06-21 | Framatome Sa | Centrifugal crusher with throwing under vacuum |
| DE112006002042A5 (en) * | 2005-05-18 | 2008-04-30 | Mijo Ljubicic | Micronized mineral materials and their production |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE387995C (en) * | 1924-01-07 | Plauson S Forschungsinstitut G | Process for the dry crushing of solid materials down to a particle size below 0.008 mm in diameter | |
| US2609993A (en) * | 1946-04-09 | 1952-09-09 | Plaroc Inc | Impact pulverizing mill, including both cooling and vacuum means |
| FR2347102A1 (en) * | 1976-04-07 | 1977-11-04 | Planiol Rene | IMPROVEMENTS TO VACUUM CENTRIFUGAL CRUSHERS |
| US4059231A (en) * | 1976-07-16 | 1977-11-22 | Grefco, Inc. | Method and apparatus for selectively comminuting particles of a frangible material |
| FR2371233A1 (en) * | 1976-11-23 | 1978-06-16 | Creusot Loire | VACUUM PROJECTION GRINDER |
-
1981
- 1981-04-13 SE SE8102343A patent/SE432719B/en not_active IP Right Cessation
-
1982
- 1982-04-08 WO PCT/SE1982/000117 patent/WO1982003572A1/en active IP Right Grant
- 1982-04-08 JP JP50128382A patent/JPS58500600A/en active Granted
- 1982-04-08 EP EP19820901181 patent/EP0088762B1/en not_active Expired
- 1982-04-08 DE DE8282901181T patent/DE3265548D1/en not_active Expired
- 1982-04-13 CA CA000400899A patent/CA1182089A/en not_active Expired
-
1989
- 1989-01-31 CA CA000589704A patent/CA1261309B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| SE8102343L (en) | 1982-10-14 |
| SE432719B (en) | 1984-04-16 |
| JPS58500600A (en) | 1983-04-21 |
| WO1982003572A1 (en) | 1982-10-28 |
| CA1182089A (en) | 1985-02-05 |
| EP0088762A1 (en) | 1983-09-21 |
| EP0088762B1 (en) | 1985-08-21 |
| DE3265548D1 (en) | 1985-09-26 |
| JPH0251675B2 (en) | 1990-11-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0568941B1 (en) | Pulverizing apparatus | |
| US3815833A (en) | Method and apparatus for grinding thermoplastic material | |
| US4697743A (en) | Method of finely crushing particles of material in an impact mill and apparatus for performing the method | |
| CA1261309B (en) | Method of finely crushing particles of material in a centrifigual mill and apparatus for performing the method | |
| CN102441474B (en) | Cyclonic jet mill | |
| JPH0420669B2 (en) | ||
| CA2530447C (en) | Device and method for comminuting materials | |
| CN108187869B (en) | Centrifugal collision pulverizer | |
| CN216936271U (en) | Crushing and separating device of vertical shaft opposite-impact crusher | |
| US3598326A (en) | Ore grinding mechanism and method | |
| US4919339A (en) | Method and apparatus for improving the grinding result of a pressure chamber grinder | |
| CN210700506U (en) | Airflow collision type crusher | |
| US3428259A (en) | Process for pulverizing material | |
| CN219129480U (en) | Improved jet mill | |
| JP2000015127A (en) | Pneumatic crusher provided with plural accelerating nozzles and manufacture of toner | |
| KR19980017130U (en) | Ultra Fine Grinding Machine | |
| CN1129610A (en) | Fluid-bed opposite-jetting superthin air flow crusher | |
| CN214320432U (en) | Air flow crusher | |
| CN221268344U (en) | Taiji collision crusher | |
| CN205032217U (en) | Fine grinding mill | |
| CN216965391U (en) | Airflow separation mill | |
| CN201735428U (en) | Dust-free environment-friendly Raymond mill | |
| CN103203270A (en) | Improved fluidized bed jet mill | |
| CN118904504B (en) | Briquette processing and manufacturing equipment | |
| CN218250681U (en) | High-speed stirring mill and grinding machine without grinding media |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| NARE | Reissued | ||
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |