CN113182021A

CN113182021A - Vane type discrete ball milling device

Info

Publication number: CN113182021A
Application number: CN202110299277.9A
Authority: CN
Inventors: 李戴威; 王晨扬; 钱招俊; 周江玥; 李鑫
Original assignee: Nanhua University
Current assignee: Nanhua University; University of South China
Priority date: 2021-03-21
Filing date: 2021-03-21
Publication date: 2021-07-30

Abstract

The invention discloses a blade type discrete ball milling device which comprises a milling barrel, a power assembly, a mounting assembly and an impeller arranged in the milling barrel, wherein the mounting assembly is used for positioning the impeller in the milling barrel, and the power assembly is used for driving the impeller to rotate; the impeller comprises a main body and a plurality of blades fixed along the circumferential direction of the main body, and a plurality of grinding balls are placed in the grinding barrel. The invention has the beneficial effects that: the impeller rotates to impact the grinding balls at a high speed, so that the grinding balls bounce and impact materials to crush the materials.

Description

Vane type discrete ball milling device

Technical Field

The invention relates to the technical field of ball milling devices, in particular to a blade type discrete ball milling device.

Background

The ball mill is a key device for crushing the required materials after the materials are crushed. In the grinding machine of the type of ore grinding machine or chemical material, a certain amount of steel balls are filled in a cylinder body of the grinding machine to be used as grinding media, and the cylinder body is mostly a horizontal cylindrical rotating device and is driven by an outer edge gear. The cylinder rotates to generate centrifugal force to bring the steel balls to a certain height and then fall down to impact materials so as to crush the materials.

It is widely used in cement, silicate products, glass ceramics, new building materials, refractory materials, chemical fertilizers, black and nonferrous metal ore dressing and other production industries to carry out dry or wet grinding on various ores and other grindable materials.

Disclosure of Invention

The invention aims to provide a blade type discrete ball milling device which is simple and reasonable in structure, convenient to use, long in service life and good in powder milling effect.

The invention provides a blade type discrete ball milling device which comprises a milling barrel, a power assembly, a mounting assembly and an impeller, wherein the impeller is mounted in the milling barrel; the impeller comprises a main body and a plurality of blades fixed along the circumferential direction of the main body, and a plurality of grinding balls are placed in the grinding barrel.

The invention has the beneficial effects that: the impeller rotates to impact the grinding balls at a high speed, so that the grinding balls bounce and impact materials to crush the materials.

Furthermore, a plurality of small holes are formed in the blades, and the diameters of the small holes in the blades are different.

The beneficial effect of adopting the further scheme is that: the small holes are convenient for materials or grinding balls with smaller diameters to pass through, so that the differential speed between the materials and between the grinding balls is formed, and the grinding effect is improved.

Further, the blades are vertically arranged, and the width of each blade is 5-15 mm. Specifically, the blades are rectangular plate-shaped, and the width of each blade refers to the longitudinal width of each blade when the rotation center of the impeller is in the vertical direction.

Preferably: the width of the blade is 10 mm.

The beneficial effect of adopting the further scheme is that: when the width of the blade is less than 5mm, the blade is weak in strength and easy to damage; when the width of the blade is larger than 15mm, the number of times of impact between the grinding balls and the blade is small, the grinding effect is poor, the impact with large impact force can occur, and the grinding barrel or the blade is easy to damage.

Further, the blades are arranged in an inclined mode, the blades are rectangular plate-shaped, the width of each blade is 11mm, and the inclination angle of each blade is 45 degrees; and the blades are rectangular plate-shaped, and the inclination angle of the blades is the included angle between the rotation center of the impeller and the blades.

The beneficial effect of adopting the further scheme is that: when the blades are arranged obliquely, the impact strength of the grinding balls and the blades is weakened, and the grinding barrel or the blades are prevented from being damaged; however, in order to ensure that the impact strength between the grinding balls and the blades is not too small, which results in poor grinding effect, the blade width needs to be properly increased.

Further, the grinding barrel is made of organic glass; the grinding ball and the impeller are made of zirconia. The barrel grinding: the diameter D is 50mm, the barrel height H is 100mm, and the wall thickness C is 2 mm; the impeller: the diameter d is 50mm, and the blade thickness c is 2 mm; the impeller adopts five blades, and each blade is randomly provided with a hole; the grinding ball comprises: d1 is 2mm, 120; d2 is 4mm, 90; d3 is 7mm, 40.

The beneficial effect of adopting the further scheme is that: the whole structure is reasonable.

Further, the power assembly comprises a motor, a connecting seat and a first bearing; a mounting hole is formed in a bottom plate of the grinding barrel, and the first bearing is mounted in the mounting hole; the stator of the motor is fixed with the grinding barrel, the lower end of the connecting seat is fixed with the rotor of the motor, and the upper end of the connecting seat penetrates through the bearing and is fixed with the main body of the impeller.

The beneficial effect of adopting the further scheme is that: the impeller is rotated to enable the materials to be close to the outer ring of the bottom plate of the grinding barrel under the action of centrifugal force, so that the problem that the materials are spilled along the axial seam is avoided, and the whole structure is simple and reasonable.

Furthermore, a connecting rod is fixed on the upper surface of the connecting seat, a connecting hole matched with the connecting rod is formed in the main body of the impeller, and the connecting rod is matched and fixed in the connecting hole.

The beneficial effect of adopting the further scheme is that: the installation is convenient.

Furthermore, a circle of conical protruding ring is arranged on the upper surface of the connecting seat around the connecting rod, the first bearing is a first conical bearing, and the mounting hole is a conical hole; and the conical convex ring, the conical bearing I and the conical hole are all of structures with small upper parts and large lower parts. The term "conical" as used herein is not meant to be conical in the geometric sense, and refers to an article having the characteristics of a truncated cone in a geometric figure.

The beneficial effect of adopting the further scheme is that: the whole structure is simple and reasonable, and the materials are prevented from being spilled along the shaft seam.

Further, the mounting assembly comprises a base, the base is horizontally placed, and a bottom plate of the grinding barrel is supported on the base through a supporting piece; the stator of the motor is fixed on the base.

The beneficial effect of adopting the further scheme is that: the whole structure is simple and reasonable.

Further, the mounting assembly further comprises a flange, a bearing seat and a second bearing;

the flange is arranged on a rotor of the motor and is fixed with the connecting seat;

the bearing block is fixed with the bottom plate of the grinding barrel; and the outer ring of the second bearing is fixed with the bearing seat, and the inner ring of the second bearing is fixed with the flange.

The beneficial effect of adopting the further scheme is that: the rotor of the motor is restrained again, so that the operation is stable; the connecting seat can be stable support by bearing one on, avoid the gap too big, lead to the material along spilling.

Further, the mounting assembly also comprises a connecting ring, and the bearing seat comprises an annular baffle plate and an edge covering ring of which the upper end extends inwards and is provided with an edge covering;

the edge covering ring abuts against the lower surface of the bottom plate, the annular baffle abuts against the lower surface of the edge covering ring to form a circular groove, and the second bearing is installed in the circular groove;

the connecting ring is abutted against the lower surface of the annular baffle, and a bolt sequentially penetrates through the connecting ring, the annular baffle and the edge covering ring; the upper end of the bolt is in threaded connection with the bottom plate.

The beneficial effect of adopting the further scheme is that: the connecting ring can be used for fixing with the base, so that the structure is firm; during assembly, the edge covering ring is assembled firstly, then the bearing II is assembled in the edge covering ring, and then the annular baffle is assembled for fixing the bearing II; and finally, the connecting ring is in threaded connection with the bottom plate and is used for fixing the connecting ring, the annular baffle and the edge wrapping ring, and the whole structure is simple and reasonable.

Drawings

FIG. 1 is a schematic structural diagram according to a first embodiment of the present invention;

FIG. 2 is an enlarged view taken at A in FIG. 1;

FIG. 3 is a perspective view of a first embodiment of the present invention with the grinding barrel removed;

fig. 4 is a schematic structural view of an impeller according to a fourth embodiment of the present invention:

FIG. 5 is a line graph of blade width variation versus statistical effective number of collisions;

FIG. 6 is a graph of acceleration at a blade width of 25 mm;

FIG. 7 is a graph of acceleration curves for a blade width of 15 mm;

FIG. 8 is a graph of acceleration for a blade width of 10 mm;

FIG. 9 is a graph of acceleration for a blade width of 5 mm;

FIG. 10 is a graph of kinetic energy for a blade width of 25 mm;

FIG. 11 is a graph of kinetic energy for a blade width of 15 mm;

FIG. 12 is a graph of kinetic energy for a blade width of 10 mm;

FIG. 13 is a graph of kinetic energy for a blade width of 5 mm;

FIG. 14 is a graph of acceleration curves using pitched blades

FIG. 15 is a graph of kinetic energy using pitched blades.

Detailed Description

The present invention will be further described with reference to the following embodiments.

As shown in fig. 1 to 3, the invention discloses a blade type discrete ball milling device, which comprises a milling barrel 1, a power assembly, a mounting assembly and an impeller 4 mounted in the milling barrel 1, wherein the mounting assembly is used for positioning the impeller 4 in the milling barrel 1, and the power assembly is used for driving the impeller 4 to rotate; the impeller 4 comprises a main body 41 and a plurality of blades 42 fixed along the circumference of the main body 41, and a plurality of grinding balls 5 are placed in the grinding barrel 1. The impeller 4 rotates to impact the grinding balls 5 at a high speed, so that the grinding balls 5 bounce and further impact materials to crush the materials, and compared with the method that the grinding barrel 1 rotates to enable the grinding balls 5 to impact the materials, the grinding balls 5 in the invention are more active, so that the crushing effect is better, the whole structure is simple and reasonable, and the small-scale ball milling is convenient to use.

The power assembly comprises a motor 21, a connecting seat 22 and a first bearing 23; a mounting hole is formed in the bottom plate 11 of the grinding barrel 1, and the first bearing 23 is mounted in the mounting hole; the stator of the motor 21 is fixed with the grinding barrel 1, the lower end of the connecting seat 22 is fixed with the rotor of the motor 21, and the upper end of the connecting seat 22 penetrates through the first bearing 23 and is fixed with the main body 41 of the impeller 4. The impeller 4 is rotated to enable the materials to be close to the outer ring of the bottom plate 11 of the grinding barrel 1 under the action of centrifugal force, so that the problem that the materials are spilled along a shaft seam is avoided, and the whole structure is simple and reasonable.

The upper surface of the connecting seat 22 is fixed with a connecting rod 221, a connecting hole matched with the connecting rod 221 is formed in the main body 41 of the impeller 4, and the connecting rod 221 is matched and fixed in the connecting hole. The installation is convenient.

A circle of conical raised rings 222 are arranged on the upper surface of the connecting seat 22 around the connecting rod 221, the first bearing 23 is a conical bearing 23, and the mounting hole is a conical hole; and the conical convex ring 222, the conical bearing I23 and the conical hole are all of a structure with a small upper part and a large lower part. The term "conical" as used herein is not meant to be conical in the geometric sense, and refers to an article having the characteristics of a truncated cone in a geometric figure. The whole structure is simple and reasonable, and the materials are prevented from being spilled along the shaft seam.

The mounting assembly comprises a base 31, the base 31 is horizontally placed, and the bottom plate 11 of the grinding barrel 1 is supported on the base 31 through a support piece; the stator of the motor 21 is fixed to the base 31. The whole structure is simple and reasonable.

The mounting assembly further comprises a flange 32, a bearing seat 33 and a second bearing 34; the flange 32 is installed on the rotor of the motor 21 and fixed with the connecting seat 22; the bearing block 33 is fixed with the bottom plate 11 of the grinding barrel 1; the outer ring of the second bearing 34 is fixed with the bearing seat 33, and the inner ring of the second bearing 34 is fixed with the flange 32. The rotor of the motor 21 is restrained again so that the operation is stable; the connecting seat 22 can stably abut against the first bearing 23, and the phenomenon that the gap is too large to cause materials to be spilled is avoided.

The mounting assembly further comprises a connecting ring 35, and the bearing seat 33 comprises an annular baffle 331 and a binding ring 332 with a binding edge extending inwards from the upper end; the edge covering ring 332 abuts against the lower surface of the bottom plate 11, the annular baffle 331 abuts against the lower surface of the edge covering ring 332 to form a circular groove, and the second bearing 34 is installed in the circular groove; the connecting ring 35 abuts against the lower surface of the annular baffle 331, and a bolt 36 sequentially penetrates through the connecting ring 35, the annular baffle 331 and the edge covering ring 332; the upper end of the bolt 36 is connected with the bottom plate 11 in a threaded manner. The connection ring 35 may be used as a fixing with the base 31 so that the structure is firm; during assembly, the edge covering ring 332 is assembled firstly, then the second bearing 34 is assembled in the edge covering ring 332, and the annular baffle 331 is assembled for fixing the second bearing 34; and finally, the connecting ring 35 is in threaded connection with the bottom plate 11 and is used for fixing the connecting ring 35, the annular baffle 331 and the edge covering ring 332, and the whole structure is simple and reasonable.

Each of the examples and comparative examples hereinafter includes all of the above features. In addition, the main difference between the examples and the comparative examples is that the vanes 42 are different.

The first embodiment is as follows:

the blades 42 are provided with a plurality of small holes, and the diameters of the small holes on the blades 42 are different. The blades 42 are vertically arranged, and the width of the blades 42 is 5 mm. Specifically, the blade 42 has a rectangular plate shape, and the width of the blade 42 refers to the longitudinal width of the blade 42 when the rotation center of the impeller 4 is the vertical direction.

Example two:

the blades 42 are provided with a plurality of small holes, and the diameters of the small holes on the blades 42 are different. The blades 42 are vertically arranged, and the width of the blades 42 is 10 mm. Specifically, the blade 42 has a rectangular plate shape, and the width of the blade 42 refers to the longitudinal width of the blade 42 when the rotation center of the impeller 4 is the vertical direction.

Example three:

the blades 42 are provided with a plurality of small holes, and the diameters of the small holes on the blades 42 are different. The blades 42 are vertically arranged, and the width of the blades 42 is 15 mm. Specifically, the blade 42 has a rectangular plate shape, and the width of the blade 42 refers to the longitudinal width of the blade 42 when the rotation center of the impeller 4 is the vertical direction.

Comparative example one:

the blades 42 are provided with a plurality of small holes, and the diameters of the small holes on the blades 42 are different. The blades 42 are vertically arranged, and the width of the blades 42 is 25 mm. Specifically, the blade 42 has a rectangular plate shape, and the width of the blade 42 refers to the longitudinal width of the blade 42 when the rotation center of the impeller 4 is the vertical direction.

Example four:

as shown in fig. 4, the blades 42 are arranged obliquely, the blades 42 are rectangular plate-shaped, the width of the blades 42 is 11mm, and the inclination angle of the blades 42 is 45 °; the blades 42 are rectangular plates, and the inclination angle of the blades 42 is the included angle between the rotation center of the impeller 4 and the blades 42.

Setting an experiment:

the blade of the vertical ball mill is optimized, and the aim of optimizing the maximum number of times of ball grinding collision in unit time is fulfilled.

The initial conditions were set as follows:

barrel grinding: the diameter D is 50mm, the height H is 100mm, and the wall thickness C is 2 mm;

impeller: the diameter d is 50mm, the thickness c is 2mm, the width h is 25mm (five blades are adopted, and each blade is randomly perforated);

grinding balls: d 1-2 mm (120) d 2-4 mm (90) d 3-7 mm (40);

the grinding barrel is set to be organic glass. The grinding barrel in the calculation analysis assumes that no damage condition occurs, i.e. is set as a rigid body in the calculation. The impeller and the grinding ball adopt zirconia as materials, and the specific material parameters are set as follows:

material	Density kg/m3	Poisson ratio	Young's modulus pa	Hardness hra
					Zirconium oxide	6000	0.3	2e+11	90

Setting simulation boundary conditions:

and constraining the translational degree of freedom and the rotational degree of freedom of the barrel body in the x, y and z axes, giving the rotation speed of the impeller 150r/min, and constraining the translational degree of freedom in the z axis direction. The free falling condition of the grinding ball is given. ABAQU was used as the tool software for the calculations.

Setting the contact conditions:

between the grinding ball and the grinding ball, between the grinding ball and the impeller, between the grinding ball and the inner wall of the barrel, Hertz-Mingdelin contact is adopted in the normal direction, and a penalty value friction coefficient contact is adopted in the tangential direction to set the friction coefficient to be 0.3.

Initial results: the number of collisions was statistically 3.2e + 4.

Based on the initial result, the blade is optimized for many times and analyzed and verified, the optimization is carried out in the height direction and the blade inclination angle direction, and the optimization idea is as follows: fill the blade hole, with blade surface make full use of in the impetus to the grinding ball, because the grinding ball is less relatively can't fully fill up the blade region, lead to the grinding ball motion to have spatial limitation, the blade height then can't fully throw out the grinding ball, lead to the grinding ball can't make full use of gravity go on with the effective collision between the ball. Therefore, the blade width is optimized firstly in the optimization idea. In the case that other parameters and conditions of the impeller are not changed, four-wheel optimization with the blade widths of 25mm, 15mm, 10mm and 5mm is performed in sequence.

The collision times of the four blades after calculation and analysis are within 7s (including the falling process of 1.5 s) and are all in the order of 1e + 4. The blade width variation and the statistically valid number of collisions were plotted as a line graph as shown in fig. 5.

For evaluating the efficiency of the ball mill, it is not sufficient to determine the efficiency by only the number of collisions, so in this example, the further evaluation is performed by combining two important judgment bases of acceleration and kinetic energy. From the acceleration formula F ═ ma, it can be known that the acceleration of a certain mass changes once, i.e. the ball is stressed once, i.e. the ball collision counts once. The grinding efficiency is linked with the impact force F, the acceleration a and the number of impacts N.

As shown in the acceleration graphs of fig. 6 to 9: when the blade width h is equal to 25mm, the acceleration change times and the amplitude are inferior to those of the other three blade widths, so that the impeller with h equal to 25mm is eliminated first, when h equal to 15mm, the acceleration change times are equivalent to those when h equal to 10mm and h equal to 5mm, but the amplitude is inferior to that when h equal to 10mm and h equal to 5 mm. The acceleration change times and the amplitude of the impeller are not obviously changed when h is 10mm and h is 5mm, which shows that when h is less than 10mm, the influence on the grinding efficiency is not obvious. In order to ensure that the impeller has higher strength and yield is not easy to occur, in the optimization of the embodiment, the impeller with h being 10mm is preferably selected as the optimal result:

as shown in the kinetic energy graphs of fig. 10-13: after 2 seconds of comparison, the kinetic energy generated by the impeller set h & lt 5mm is slightly lower than that generated by the other three sets, i.e. h & lt 10mm, h & lt 15mm, and h & lt 25mm, and the kinetic energy has no obvious change (only decreasing within 0.5) in comparison, and the difference of the three sets on the stable power is small as shown in the formula Pt & lt W & gtE. Three kinetic energy jumps (here we consider the amplitude of the kinetic energy exceeding the fall to be one kinetic energy jump) occur in the set h-25 mm, and one kinetic energy jump occurs in the set h-10 mm. The kinetic energy jump has advantages and disadvantages, and the advantages are that each time the kinetic energy jump may act on the collision of the grinding balls to the materials, and the disadvantages are that the kinetic energy jump causes unstable power or causes damage to the ball mill.

In addition to optimizing the width of the blade, the installation angle of the blade is optimized in the present example, and it is found that when the width of the blade is 11mm and the inclination angle is 45 °, the grinding efficiency is close to that when the width of the blade is 10mm, and the number of times of collision is 4e + 4. The optimized blade has the advantages that the inclined blade can reduce the normal impact of the grinding balls on the blade and can effectively convert the normal behavior into the tangential behavior, so that the grinding balls are thrown out to collide with the balls, and the design method can reduce the damage of the blade and prolong the service life. The acceleration curve and the energy curve are shown in fig. 14 and fig. 15.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The blade type discrete ball milling device is characterized by comprising a milling barrel (1), a power assembly, a mounting assembly and an impeller (4) installed in the milling barrel (1), wherein the mounting assembly is used for positioning the impeller (4) in the milling barrel (1), and the power assembly is used for driving the impeller (4) to rotate; the impeller (4) comprises a main body (41) and a plurality of blades (42) fixed along the circumferential direction of the main body (41), and a plurality of grinding balls (5) are placed in the grinding barrel (1).

2. The blade type discrete ball milling apparatus as claimed in claim 1, wherein the blades (42) are provided with a plurality of small holes.

3. The blade type discrete ball milling device according to claim 2, wherein the blades (42) are vertically arranged, and the width of the blades (42) is 5mm-15 mm.

4. The blade type discrete ball milling device according to claim 1, wherein the blades (42) are arranged obliquely, and the width of the blades (42) is 6mm-18 mm.

5. The blade type discrete ball milling device according to claim 1, wherein the power assembly comprises a motor (21), a connecting seat (22) and a first bearing (23); a mounting hole is formed in a bottom plate (11) of the grinding barrel (1), and the first bearing (23) is mounted in the mounting hole; the stator of the motor (21) is fixed with the grinding barrel (1), the lower end of the connecting seat (22) is fixed with the rotor of the motor (21), and the upper end of the connecting seat (22) penetrates through the first bearing (23) and is fixed with the main body (41) of the impeller (4).

6. The blade type discrete ball milling device according to claim 5, wherein a connecting rod (221) is fixed on the upper surface of the connecting seat (22), a connecting hole matched with the connecting rod (221) is formed in the body (41) of the impeller (4), and the connecting rod (221) is matched and fixed in the connecting hole.

7. The blade type ball discrete milling device as claimed in claim 6, wherein the upper surface of the connecting base (22) is provided with a circle of conical raised rings (222) around the connecting rod (221), the first bearing (23) is a conical first bearing (23), and the mounting hole is a conical hole; and the conical convex ring (222), the conical bearing I (23) and the conical hole are all of a structure with a small top and a large bottom.

8. The ball mill apparatus with blade type dispersion according to claim 5, characterized in that the mounting assembly comprises a base (31), the base (31) is horizontally placed, the bottom plate (11) of the mill barrel (1) is supported on the base (31) with a support; the stator of the motor (21) is fixed on the base (31).

9. The paddle type discrete ball milling apparatus as recited in claim 5, wherein the mounting assembly further comprises a flange (32), a bearing block (33), and a second bearing (34);

the flange (32) is arranged on a rotor of the motor (21) and is fixed with the connecting seat (22);

the bearing seat (33) is fixed with a bottom plate (11) of the grinding barrel (1); the outer ring of the second bearing (34) is fixed with the bearing seat (33), and the inner ring of the second bearing (34) is fixed with the flange (32).

10. The paddle type discrete ball mill apparatus as recited in claim 9, wherein the mounting assembly further comprises a connecting ring (35), the bearing housing (33) comprising an annular baffle (331) and an overclad ring (332) having an upper end with an overclad extending inwardly therefrom;

the edge covering ring (332) abuts against the lower surface of the bottom plate (11), the annular baffle (331) abuts against the lower surface of the edge covering ring (332) to form a circular groove, and the second bearing (34) is installed in the circular groove;

the connecting ring (35) abuts against the lower surface of the annular baffle (331), and a bolt (36) sequentially penetrates through the connecting ring (35), the annular baffle (331) and the edge wrapping ring (332); the upper end of the bolt (36) is in threaded connection with the bottom plate (11).