CA1078352A - Centrifugal mill - Google Patents
Centrifugal millInfo
- Publication number
- CA1078352A CA1078352A CA260,993A CA260993A CA1078352A CA 1078352 A CA1078352 A CA 1078352A CA 260993 A CA260993 A CA 260993A CA 1078352 A CA1078352 A CA 1078352A
- Authority
- CA
- Canada
- Prior art keywords
- axis
- drum
- grinding drum
- revolution
- ratio
- 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
- B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
- B02C17/14—Mills in which the charge to be ground is turned over by movements of the container other than by rotating, e.g. by swinging, vibrating, tilting
Landscapes
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Crushing And Grinding (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A centrifugal mill comprising a cylindrical grinding drum, which rotates on its own axis and simultaneously revolves at a constant angular velocity ratio on a circular orbit around a stationary axis of revolution, which is parallel to the drum axis. The distance from the axis of the drum to the axis of revolution is smaller than the radius of the grinding drum. The ratio of the diameter G of the circular orbit to the inside diameter D of the grinding drum is between 0.3 and 1.0 and the ratio R of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angular velocity of the rotation of the grinding drum on its own axis is in the range from to , the ratio R
being considered to be negative when the two angular movements are in opposite senses, and positive when two angular movements are in the same sense. The mill comprises a feeder provided at one end of the grinding drum, and discharge means provided at the other end of the grinding drum.
A centrifugal mill comprising a cylindrical grinding drum, which rotates on its own axis and simultaneously revolves at a constant angular velocity ratio on a circular orbit around a stationary axis of revolution, which is parallel to the drum axis. The distance from the axis of the drum to the axis of revolution is smaller than the radius of the grinding drum. The ratio of the diameter G of the circular orbit to the inside diameter D of the grinding drum is between 0.3 and 1.0 and the ratio R of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angular velocity of the rotation of the grinding drum on its own axis is in the range from to , the ratio R
being considered to be negative when the two angular movements are in opposite senses, and positive when two angular movements are in the same sense. The mill comprises a feeder provided at one end of the grinding drum, and discharge means provided at the other end of the grinding drum.
Description
107835Z ; , This invention relates to a centrifugal mill comprising a cylindrical grinding drum, which rotates on its own axis and simultaneously revolves at a constant angular velocity ratio on a circular'orbit around a stationary axis of revolution, which is parallel to the drum axis, the distance from the axis of the drum to the axis of revolution being smaller than the radius of the grinding drum, and a drive mechanism for rotating the grinding drum on its own axis, and for revolving the drum on the circular orbit.
Centrifugal mills for intermittent trial opera- `
tion have been described in "Rock Product", February 1951, '~
pages 93-97.
Printed German Application 10 13 946 also dis-closes a centrifugal mill which is used for batch opera-tion and in which the distance from the axis of the drum to the axis of revolution is smaller than the radius of the grinding drum. As a result, the operation of the mill shall not be restricted by a critical or limited ~-angular velocity. The critical velocity is the lowest velocity at which the material being ground and the grinding elements are caused by centrifugal force to form a covering on the inside surface of the grinding drum so that grinding is no longer effected. On the other hand, the mere selection of a distance from the axis of the drum to the axis of revolution which is smaller than the radius of the grinding drum will not ~-ensure an operation under subcritical conditions and a high grinding capacity.
It is an object of the invention to provide a centrifugal mill which enables a continuous operation in the subcritical range with a high grinding capacity - 1 - .
1Cl17~352 , per unit of volume of the grinding drum.
This object is accomplished according to the present invention by the provision of a centrifugal mill comprising:
a cylindrical grinding drum, which rotates on its own axis and simultaneously revolves at a constant angular velocity ratio on a circular orbit around a stationary axis of revolution which is parallel to the drum axis, the distance from the axis of the drum to the axis of revolution being smaller than the radius of the grinding drum; a drive mechanism for rotating the grinding drum on its own, axis and for revolving the drum on the circular orbit about said stationary axis; a feeder provided at one end of the grinding drum, and discharge means provided at the other end of the grinding drum, characterized in that the ratio of the diameter G of the circular orbit to the inside diameter D
of the grinding drum is between 0.3 and 1.0, and the ratio R
of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angular velocity of the rotation of the grinding drum on its axis is in the range from R = ~ r~ to R = ~
the ratio R being considered to be negative when the two angular movements are in opposite senses, and positive when the two angular movements are in the same sense.
The combination of these features ensures that the mill always operates in the subcritical range and with a high grinding capacity.
According to a preferred feature of the invention, the ratio R of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angula'r velocity of the rotation of the drum on its own axis is R = -1. In this case, the grinding capacity will be particularly high, the centrifugal forces will be equal at all points of the,cross-section of the grinding drum, and the
Centrifugal mills for intermittent trial opera- `
tion have been described in "Rock Product", February 1951, '~
pages 93-97.
Printed German Application 10 13 946 also dis-closes a centrifugal mill which is used for batch opera-tion and in which the distance from the axis of the drum to the axis of revolution is smaller than the radius of the grinding drum. As a result, the operation of the mill shall not be restricted by a critical or limited ~-angular velocity. The critical velocity is the lowest velocity at which the material being ground and the grinding elements are caused by centrifugal force to form a covering on the inside surface of the grinding drum so that grinding is no longer effected. On the other hand, the mere selection of a distance from the axis of the drum to the axis of revolution which is smaller than the radius of the grinding drum will not ~-ensure an operation under subcritical conditions and a high grinding capacity.
It is an object of the invention to provide a centrifugal mill which enables a continuous operation in the subcritical range with a high grinding capacity - 1 - .
1Cl17~352 , per unit of volume of the grinding drum.
This object is accomplished according to the present invention by the provision of a centrifugal mill comprising:
a cylindrical grinding drum, which rotates on its own axis and simultaneously revolves at a constant angular velocity ratio on a circular orbit around a stationary axis of revolution which is parallel to the drum axis, the distance from the axis of the drum to the axis of revolution being smaller than the radius of the grinding drum; a drive mechanism for rotating the grinding drum on its own, axis and for revolving the drum on the circular orbit about said stationary axis; a feeder provided at one end of the grinding drum, and discharge means provided at the other end of the grinding drum, characterized in that the ratio of the diameter G of the circular orbit to the inside diameter D
of the grinding drum is between 0.3 and 1.0, and the ratio R
of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angular velocity of the rotation of the grinding drum on its axis is in the range from R = ~ r~ to R = ~
the ratio R being considered to be negative when the two angular movements are in opposite senses, and positive when the two angular movements are in the same sense.
The combination of these features ensures that the mill always operates in the subcritical range and with a high grinding capacity.
According to a preferred feature of the invention, the ratio R of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angula'r velocity of the rotation of the drum on its own axis is R = -1. In this case, the grinding capacity will be particularly high, the centrifugal forces will be equal at all points of the,cross-section of the grinding drum, and the
- 2 -,, , : : - . .,.~ ., , , , . - . :
acceleration vectors will be parallel and have the same direction at all points.
The invention will be explained more fully and by way of example with reference to the drawings, in which: ;
~ .
- 2a -1~7835Z
FIGURE 1 is a vertical sectional view showing a centrifugal mill having a vertical grinding drum, FIGURE 2 is a sectional view taken on line I-I in Figure l;
FIGURE 3 is a vertical sectional view showing different discharge means; and FIGURE 4 is an enlarged sectional view taken on line II-II in Figure 3.
In Figures 1 to 4 the grinding drum 1 is shown to have a smooth liner. Lifting bars are provided on the inside in practice but are not shown for the sake of clearness. The grinding drum 1 is provided with hollow trunnions 2 and 3, which are mounted in bearings 4 arranged in bearing housings 5 and 6. The bearing housings are integral with a frame, which also includes longitudinal members 7 and 8. The hollow trunnion 2 is -connected to a special spiral feeder 9, which rotates with the grinding drum 1. The hollow trunnion 3 dis-charges the material into a discharge chute 10, which discharges into an annular collecting trough 11. A
gear 12 is secured to the hollow trunnion 3 and in mesh with three gears 13, the last of which is rigidly con-nected to the mounting pin 14. The frame has end members 15 and 16, which are rotatably connected by bearings 17 to a base frame. The base frame carries a hollow trunnion 18 adjacent to the end member 15 and a mounting shaft 19 adjacent to the other end member 16.
The mounting shaft 19 and the hollow trunnion 18 define an axis of revolution 20. A revolution around this axis is effected by a belt 21 and a belt pulley 22.
The axis of the grinding drum 1 is designated 23 in Figure 2. The drawings show an arrangement in which ., ... ~ . , . , .' . ; :
~07835Z
the ratio of the diameter G of the circular orbit around the axis of revolution 20 to the inside diameter of the grinding drum 1 is approximately 0.5. The transmission ratio between the hollow trunnion 3 and the mounting pin 14 is important and corresponds to the ratio R. This transmission ratio determines the relative angular velo-city of the rotation of the grinding drum 1 in the simu-lated gravitational field which is produced by the revo-lution of the axis 23 around the axis 20. A transmission ratio R = - 1 is preferred so that a certain diameter of the grinding drum always remains parallel to itself during the revolution. The belt 21 is driven by drive means which are not shown. The material is fed through the hollow trunnion 18 into the feeder 9, which feeds the material through the hollow trunnion 2 into the grinding drum 1. Whereas the coarse particles are retained by the screen 25 in the grinding drum 1, the ground material ;
is discharged to the collecting trough 11. The belt 21 and the belt pulley 22 associated with fixed trunnions 18 and 19 may be replaced by different drive means. The hub 26 provided with the lower bearing 17 and fixedly connected to the frame may be driven by another motor through a belt drive or a gear train. The gear train 12/13 is only an example of means for rotating the grind-ing drum 1. The highest speed at which the grinding drum 1 may be rotated is limited only by the mechanical strength of the mill. To avoid rotary unbalance, the longitudinal member 7 is weighted to balance out the ,~
weight of the grinding drum 1 and of the charge therein.
In the embodiment provided with the discharge means shown in Figures 3 and 4, the grinding dxum 1 is provided with an end plate 27, which has a central iC~7835Z
opening, which is spaced from the plate 29 by spacers 28. Material which enters the space between the plates 27 and 29 is radially discharged between the spacers.
A spiral discharge member 30, which may consist of round rod, is arranged to return coarse material into the grinding drum 1.
A horizontally disposed mill may be similarly constructed.
acceleration vectors will be parallel and have the same direction at all points.
The invention will be explained more fully and by way of example with reference to the drawings, in which: ;
~ .
- 2a -1~7835Z
FIGURE 1 is a vertical sectional view showing a centrifugal mill having a vertical grinding drum, FIGURE 2 is a sectional view taken on line I-I in Figure l;
FIGURE 3 is a vertical sectional view showing different discharge means; and FIGURE 4 is an enlarged sectional view taken on line II-II in Figure 3.
In Figures 1 to 4 the grinding drum 1 is shown to have a smooth liner. Lifting bars are provided on the inside in practice but are not shown for the sake of clearness. The grinding drum 1 is provided with hollow trunnions 2 and 3, which are mounted in bearings 4 arranged in bearing housings 5 and 6. The bearing housings are integral with a frame, which also includes longitudinal members 7 and 8. The hollow trunnion 2 is -connected to a special spiral feeder 9, which rotates with the grinding drum 1. The hollow trunnion 3 dis-charges the material into a discharge chute 10, which discharges into an annular collecting trough 11. A
gear 12 is secured to the hollow trunnion 3 and in mesh with three gears 13, the last of which is rigidly con-nected to the mounting pin 14. The frame has end members 15 and 16, which are rotatably connected by bearings 17 to a base frame. The base frame carries a hollow trunnion 18 adjacent to the end member 15 and a mounting shaft 19 adjacent to the other end member 16.
The mounting shaft 19 and the hollow trunnion 18 define an axis of revolution 20. A revolution around this axis is effected by a belt 21 and a belt pulley 22.
The axis of the grinding drum 1 is designated 23 in Figure 2. The drawings show an arrangement in which ., ... ~ . , . , .' . ; :
~07835Z
the ratio of the diameter G of the circular orbit around the axis of revolution 20 to the inside diameter of the grinding drum 1 is approximately 0.5. The transmission ratio between the hollow trunnion 3 and the mounting pin 14 is important and corresponds to the ratio R. This transmission ratio determines the relative angular velo-city of the rotation of the grinding drum 1 in the simu-lated gravitational field which is produced by the revo-lution of the axis 23 around the axis 20. A transmission ratio R = - 1 is preferred so that a certain diameter of the grinding drum always remains parallel to itself during the revolution. The belt 21 is driven by drive means which are not shown. The material is fed through the hollow trunnion 18 into the feeder 9, which feeds the material through the hollow trunnion 2 into the grinding drum 1. Whereas the coarse particles are retained by the screen 25 in the grinding drum 1, the ground material ;
is discharged to the collecting trough 11. The belt 21 and the belt pulley 22 associated with fixed trunnions 18 and 19 may be replaced by different drive means. The hub 26 provided with the lower bearing 17 and fixedly connected to the frame may be driven by another motor through a belt drive or a gear train. The gear train 12/13 is only an example of means for rotating the grind-ing drum 1. The highest speed at which the grinding drum 1 may be rotated is limited only by the mechanical strength of the mill. To avoid rotary unbalance, the longitudinal member 7 is weighted to balance out the ,~
weight of the grinding drum 1 and of the charge therein.
In the embodiment provided with the discharge means shown in Figures 3 and 4, the grinding dxum 1 is provided with an end plate 27, which has a central iC~7835Z
opening, which is spaced from the plate 29 by spacers 28. Material which enters the space between the plates 27 and 29 is radially discharged between the spacers.
A spiral discharge member 30, which may consist of round rod, is arranged to return coarse material into the grinding drum 1.
A horizontally disposed mill may be similarly constructed.
Claims (2)
1. A centrifugal mill comprising: a cylindrical grinding drum, which rotates on its own axis and simultaneously revolves at a constant angular velocity ratio on a circular orbit around a stationary axis of revolution which is parallel to the drum axis, the distance from the axis of the drum to the axis of revolution being smaller than the radius of the grinding drum; a drive mechanism for rotating the grinding drum.
on its own axis and for revolving the drum on the circular orbit about said stationary axis; a feeder provided at one end of the grinding drum, and discharge means provided at the other end of the grinding drum, characterized in that the ratio of the diameter G of the circular orbit to the inside diameter D
of the grinding drum is between 0.3 and 1.0, and the ratio R
of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angular velocity of the rotation of the grinding drum on its axis is in the range from to , the ratio R being considered to be negative when the two angular movements are in opposite senses, and positive when the two angular movements are in the same sense.
on its own axis and for revolving the drum on the circular orbit about said stationary axis; a feeder provided at one end of the grinding drum, and discharge means provided at the other end of the grinding drum, characterized in that the ratio of the diameter G of the circular orbit to the inside diameter D
of the grinding drum is between 0.3 and 1.0, and the ratio R
of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angular velocity of the rotation of the grinding drum on its axis is in the range from to , the ratio R being considered to be negative when the two angular movements are in opposite senses, and positive when the two angular movements are in the same sense.
2. A centrifugal mill according to claim 1, characterized in that the ratio R of the angular velocity of the revolution of the grinding drum on the circular orbit around the axis of revolution to the angular velocity of the rotation of the drum on its own axis is R = - 1.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA755774A ZA755774B (en) | 1975-09-10 | 1975-09-10 | Gyratory tumbling mills |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078352A true CA1078352A (en) | 1980-05-27 |
Family
ID=25569429
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA260,993A Expired CA1078352A (en) | 1975-09-10 | 1976-09-09 | Centrifugal mill |
Country Status (3)
| Country | Link |
|---|---|
| BE (1) | BE845966A (en) |
| CA (1) | CA1078352A (en) |
| ZA (1) | ZA755774B (en) |
-
1975
- 1975-09-10 ZA ZA755774A patent/ZA755774B/en unknown
-
1976
- 1976-09-08 BE BE6045666A patent/BE845966A/en not_active IP Right Cessation
- 1976-09-09 CA CA260,993A patent/CA1078352A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ZA755774B (en) | 1977-02-23 |
| BE845966A (en) | 1977-03-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |