CN111570019A

CN111570019A - Superfine powder mill

Info

Publication number: CN111570019A
Application number: CN202010473085.0A
Authority: CN
Inventors: 薛成龙; 王守仁; 温道胜; 张明远; 李金坤; 时晓宇; 杨冰冰; 郭宇
Original assignee: University of Jinan
Current assignee: University of Jinan
Priority date: 2020-05-29
Filing date: 2020-05-29
Publication date: 2020-08-25

Abstract

The invention discloses an ultrafine powder mill, the basic structure of which comprises: a housing; a rotating shaft; a driver; and a rotor. The pin rod is not interfered by the axial arrangement or the approximately axial arrangement of the pin rod on the rotating shaft, so that the pin rod is easy to maintain. In addition, because the pins are axially arranged or approximately axially arranged on the rotating shaft, the occupied space is relatively small, and the pins are axially arranged, for example, and can be radially arranged in multiple layers, the limitation of the number of the pins is greatly reduced, and the structure of the superfine powder grinding machine based on the embodiment of the invention is more compact under the condition of the same grinding capacity.

Description

Superfine powder mill

Technical Field

The invention relates to an ultrafine powder mill, in particular to a pin-type ultrafine powder mill.

Background

The superfine powder refers to fine powder (fine powder) with the average diameter of less than 10 μm, and the application of the superfine powder is very wide, and the superfine powder has wider application and larger demand in the emerging technical fields of powder metallurgy, laser cladding, 3D printing and the like. The superfine powder technology is a new technology which is across disciplines and industries and is formed by intersecting related disciplines (such as machinery, physics, chemistry, mechanics, computer control and the like) under the situation of modern scientific and technical integration. With the rapid development of China's society and economy, the demand for powder is increasing.

The preparation process of the superfine powder mainly comprises three types, namely a mechanical crushing method, a physical method and a chemical synthesis method, wherein the mechanical method mainly comprises a crushing and grinding method, a jet milling method, a mechanical impact method and the like. The mechanical impact method mainly depends on a mechanical impact crusher to prepare ultrafine powder, and the mechanical impact crusher is equipment for crushing materials by utilizing impact elements (rods, blades, feather plates and the like) rotating around a horizontal or vertical shaft at a high speed to impact the materials violently and generating various effects of high-frequency strong impact, shearing, friction, airflow vibration and the like between the materials and a stator and between material particles. A more common mechanical impact mill is a pin mill.

The crushing members of the pin crusher are cylindrical or regular polygonal prism (generally regular quadrangular prism or regular hexagonal prism) pins which are generally radially arrayed on a cylindrical wrapper plate to form a rotor, i.e. one end of each pin is riveted on the wrapper plate and extends radially, and the whole structure is similar to a spike roller. This kind of pin rod assembly structure, because only one end of pin rod is fixed, fixed reliability is relatively poor, simultaneously, in order to avoid the pin rod to arrange on the wrapper sheet too densely, still generally dispose the stator that surrounds the rotor, also the array has the pin rod on the stator, and the pin rod on the stator staggers each other with the pin rod on the rotor in the axial of stator, and the feed inlet need avoid opening stator and rotor, and the position that sets up of feed inlet can receive great influence.

Typically, as in chinese patent document CN2425708Y, a turbine pin micronizer is disclosed, which has a rotor consisting of a distribution disc, hammer clamping plates, hammering blocks and a fan disc, and a casing with radially oriented pins fixed circumferentially staggered. Due to the staggered arrangement of the pin rods and the hammer clamp plates, the maintainability of the hammer clamp plates and the pin rods is relatively poor. In addition, the crushing effect of the pin rods is passive, and the material is passively crushed on the pin rods by means of the driving of the hammer clamp plates. The applicable materials are biomass materials such as rice husks and corn cobs, the resistance is very large, the pin bars are easy to damage, and the material is suitable for poor maintainability.

Chinese patent document CN2299660Y discloses a pin-type impact autogenous grinding pulverizer-classifier, in which the pins are divided into two groups, one of which is fixed on a stator plate, the other is fixed on a pulverizing disk, the pulverizing disk is a rotating member, the pins on the stator plate and the pins on the pulverizing disk are also arranged in a staggered manner, and the distance between the two groups of pins is required to be small, so as to grind the material entering the gap between the pins. Therefore, the crushing mode mainly depends on the materials in the crushing chamber to be impacted by the pin rods fixed on the crushing disc and the stator plate and to be crushed by mutual self-grinding action. Because the pins are arranged in a staggered manner, the maintainability of the pins is relatively poor, and the stator plate and the crushing disc are not easy to be taken out independently.

Disclosure of Invention

The invention aims to provide an ultrafine powder grinding machine which is compact in structure and relatively good in maintainability, and belongs to a pin-rod type ultrafine powder grinding machine.

In an embodiment of the present invention, there is provided an ultrafine powder mill, the basic structure of which includes:

the shell is horizontally arranged, two ends of the shell are sealed by end plates and are provided with inner cylindrical surfaces, and the center of each end plate is provided with a bearing seat hole;

the end part of the rotating shaft is supported in the bearing seat hole at the end through a bearing;

the output of the driver is connected with the rotating shaft so as to drive the rotating shaft to rotate;

the rotor comprises a pair of fixing plates parallel to the end plates, and two ends of the part of the rotating shaft in the shell are respectively fixed with one fixing plate; the rotor also comprises a pin rod group, the end part of the pin rod group is fixed on the end fixing plate, and the pin rod in the group is vertical to the fixing plate or forms a given angle with the fixing plate;

if the pin rod is vertical to the fixed plate, an impeller which supplies air to a direction far away from the fixed plate is arranged on the outer side of the fixed plate, and a sieve plate is arranged on the outer side of the impeller;

if the pin rod and the fixed plate form a given angle, the pin rod is provided with a blade structure to generate an air supply effect, and a sieve plate is arranged on the outer side of the fixed plate at the air supply direction side;

correspondingly, the end plate on the side of the sieve plate is provided with a discharge hole, and the middle of the upper side of the shell is provided with a feed hole.

Alternatively, the pins have two annular arrays on the rotor, forming an outer pin array on the centrifugal side and an inner pin array on the centripetal side.

Optionally, the outer pin array is located at a radial end of the rotor;

the inner pin array is located at the position two thirds R-three quarters R of the radial distance from the axis of the rotor;

wherein R is the radius of the reference circle of the outer pin array.

Optionally, the number of inner pins is 2 times the number of outer pins.

Optionally, the given angle is 85-89 degrees.

Optionally, the inner cylindrical surface of the housing is fitted with a liner.

Optionally, the lining plate is formed by splicing a plurality of arc-shaped lining plate blocks;

the arc-shaped liner blocks are fixed to the inner surface of the shell by screws inserted through the outside of the shell.

Optionally, the bearing is a magnetic bearing;

the motor distributed by the driver is a magnetic suspension motor.

Optionally, the feed inlet is fitted with a filter screen.

Optionally, a settling distance is reserved between the sieve plate and the end plate on the side where the sieve plate is located;

the discharge port is positioned at the lower part of the end plate.

In the embodiment of the invention, the rotor is constructed on a rotating shaft, the rotor comprises fixing plates respectively arranged at two ends of the rotating shaft positioned in the shell, and two ends of the pin rod are correspondingly and fixedly connected with the fixing plates at the end where the pin rod is positioned. The pin rod is not interfered by the axial arrangement or the approximately axial arrangement of the pin rod on the rotating shaft, so that the pin rod is easy to maintain. In addition, because the pins are axially arranged or approximately axially arranged on the rotating shaft, the occupied space is relatively small, and the pins are axially arranged, for example, and can be radially arranged in multiple layers, the limitation of the number of the pins is greatly reduced, and the structure of the superfine powder grinding machine based on the embodiment of the invention is more compact under the condition of the same grinding capacity.

Drawings

FIG. 1 is a schematic perspective view of an ultrafine powder mill according to an embodiment.

FIG. 2 is a schematic view of an embodiment of an ultrafine powder mill.

Fig. 3 is a sectional view a-a of fig. 2.

In the figure: 1. the device comprises a motor, 2 parts of a shell, 3 parts of a front end plate, 4 parts of screws, 5 parts of a feeding hopper, 6 parts of a rear end plate, 7 parts of a crushing cavity, 8 parts of a rotating shaft, 9 parts of a magnetic suspension bearing, 10 parts of a coupler, 11 parts of a lining plate, 12 parts of a filter screen, 13 parts of a screen plate, 14 parts of an impeller, 15 parts of a settling cavity, 16 parts of an inner pin rod, 17 parts of an outer pin rod, 18 parts of a front fixing plate, 19 parts of a rear fixing plate and 20 parts of a discharge hole.

Detailed Description

In general, the pins of the conventional pin-type ultrafine powder mill are radially arranged, and the pins are usually mounted on two parts, one is a rotor with a wrapper, and the other is the shell 2 itself, and the pins on the two parts are arranged in a staggered manner. Due to the limitation of radial space and the limitation of the packing plate body, the action space of the pin rod is smaller, or the crushing space is smaller. And because two sets of pins are arranged in a staggered manner, the use condition of the pins is difficult to check, the overall assembly difficulty is high, relatively speaking, the overall maintainability is relatively poor, and the overall dimension specification is relatively large. For example, in a wrapper sheet, in order to mount a relatively large number of pins, the cylindrical surface defined by the wrapper sheet needs to have a sufficiently large diameter, the dispersion space of the powder is relatively small, and in order to obtain a sufficiently large pulverizing capacity, it is inevitable that the size of the ultrafine powder mill is relatively large.

In the embodiment of the present invention, the pin rod is arranged in a transverse direction, which is different from the conventional radial direction, and can be analogized to an axial direction, but not limited to being parallel to the rotating shaft 8 as shown in fig. 3, and can also be at an angle with the rotating shaft 8, and the angle can also be characterized as an angle formed between the front end plate 3 or the rear end plate 6 as shown in fig. 3, and the angle is called a given angle.

Note: the radial and axial directions in the present invention are referenced to the inner cylindrical surface of the housing 2 unless otherwise specified.

In the structure shown in fig. 1 to 3, the basic structure of the ultrafine powder mill includes a horizontal housing 2, a rotating shaft 8 inserted into the housing 2 from a front end plate 3, a motor 1 for driving the rotating shaft 8, a rotor mounted on the rotating shaft 8, and an impeller 14 mounted on the rotating shaft 8 in fig. 3. A sieve plate 13 is also provided on the right side of the impeller 14 in fig. 3.

Regarding the housing 2, in the ultrafine powder mill, the housing 2 is generally a circular housing, and is divided into a horizontal type and a vertical type according to the arrangement of the axis thereof, wherein the axis of the housing 2 is horizontal or has an angle of less than 45 degrees with the horizontal plane, which can be called as a horizontal type, and therefore, in the embodiment of the present invention, referring to fig. 3, the housing 2 has a horizontal type structure.

In fig. 3, the housing 2 comprises as a whole a cylinder and two closing plates, also called end plates, for sealing the cylinder at both ends, thus forming a relatively closed inner cylindrical space, i.e. the crushing chamber 7 shown in fig. 3.

The end plates are typically sealed by flange connection with a sealing felt.

For the housing 2, which is a static component, the rear end plate 6 of the housing 2 is mounted as a mount to other components in some applications; in some applications, the underside of the housing 2 is welded or directly pressed against a seat with an arc-shaped notch.

In fig. 3, the front end plate 3 and the rear end plate 6 are provided with central holes configured as bearing housing holes, wherein the central holes in the rear end plate 6 may be blind holes or through holes, and the air sealing is relatively simple regardless of the hole type, especially blind holes. In the case of a through hole, a bearing cap may be provided on the rear end surface of the rear end cap 6.

The main body of the shaft 8 is preferably a tubular shaft, but a solid shaft may be used, and when a tubular shaft is used, the weight of the tubular shaft is lighter under the condition of the same shear section coefficient.

Correspondingly, the rotating shaft 8 is mounted on the corresponding bearing seat hole through a bearing to form two-end support.

In fig. 1, a rotating shaft 8 is driven by a motor 1, and the motor 1 is connected to the rotating shaft 8 by a coupling 10.

In the mechanical production of ultrafine powder, the rotation speed of the rotary shaft 8 is required to be relatively high, usually in the order of ten thousand revolutions per minute, and therefore, a reduction gear may be provided for the motor 1.

The rotating shaft 8 rotates at a high speed, the service life of the bearing is relatively short, and the bearing is preferably a magnetic suspension bearing 9 in order to obtain a relatively long maintenance period.

Magnetic bearings 9(Magnetic Bearing) are a type of Bearing that uses Magnetic forces to suspend the rotor in the air, allowing the rotor to be disengaged from the stator without mechanical contact, thereby avoiding mechanical friction, providing a longer useful life for the Bearing, and providing particular advantages in high speed applications.

At present, the domestic magnetic suspension bearing has no industrial application, and the application is realized in foreign countries, so that the current magnetic suspension bearing is an imported bearing. Although relatively expensive, a long-term reliable bearing, in particular maintenance-free, is particularly important for the rotating shaft 8 rotating at high speed.

As described above, since the rotor speed of the ultrafine powder mill is relatively high, the motor 1 is preferably a magnetic levitation motor in order to adapt to a high-speed rotation application. Compared with the current situation that the magnetic suspension bearing 9 needs to be imported at present, the domestic application of the magnetic suspension motor is mature, and details are not repeated.

Compared with the common motor, the magnetic levitation motor can directly output higher speed.

In fig. 3, a rotor is mounted on the rotating shaft 8 in the housing 2, and the rotor includes a pair of fixing plates parallel to the end plates, such as a front fixing plate 18 and a rear fixing plate 19 shown in fig. 3, and the fixing plates can be welded on the rotating shaft 8, or can be connected to the rotating shaft 8 by spline or other key connection, and then are axially positioned by using a round nut or a snap spring to match with a shaft shoulder.

The axial distance between the two fixing plates in the rotating shaft 8 is used for determining the installation space of the crushing component, namely the pin rod, in the structure shown in fig. 3, the pin rod takes the two fixing plates as the installation base body, and particularly, the two ends of the pin rod are fixedly connected with the fixing plates at the corresponding ends.

The pin rod and the fixing plate can be connected in a detachable mode, such as a screw connection mode, or in a non-detachable mode, such as riveting or welding.

Because the pin rod belongs to the mode that both ends are connected, for traditional pin rod single-ended fixed mode, the installation reliability improves greatly.

Two fixing plates are shown in fig. 3, and an intermediate support plate can be arranged between the two fixing plates, wherein the intermediate support plate is provided with a through hole for positioning the pin rod, and the middle part of the pin rod is supported on the through hole so as to improve the overall dynamic rigidity.

The pin is parallel to or at an angle with respect to the axis of rotation 8. for convenience of description, the pin may be perpendicular to the fixed plate or may be at a predetermined angle with respect to the fixed plate, with reference to the end face. Either type of assembly is different from the current manner of securing one end of a pin and extending radially.

If the pin is perpendicular to the fixing plate, the outer side of the fixing plate, specifically the right side shown in fig. 3, which is opposite to the side where the motor 1 is located, and the fixing plate on the side, i.e., the rear side of the rear fixing plate 1 shown in the figure, is provided with an impeller 14, the air blowing direction of the impeller 14 is a direction away from the fixing plate.

Correspondingly, a sieve plate 13 is arranged outside the impeller 14.

It will be appreciated that, in a general sense, the mating directions defined by the two plates are inward and, conversely, outward.

It will be appreciated that the feed hopper 5 shown in figure 3 is a very fine, typically micron-sized, feed material that is itself subjected to further comminution by the micronizer.

Because the specific surface area of the powder is larger, the rotor can rotate at high speed in ten thousand stages, and the generated vortex can effectively avoid the powder from depositing at the bottom of the shell 2.

In the sieve plate 13, it is understood that, in the field of powder material technology, the sifted and sieved powder is based on the powder with the desired particle size obtained, and the sieved powder is bounced off and enters the crushing cavity 7 again to be crushed.

It will also be appreciated that the discharge opening 20 has a certain supply pressure and that the crushed material is discharged by wind relatively, and that the crushing chamber 7 has a certain underpressure for sucking in material when fed through the feed hopper 5.

For the filter screens 12 and the screen plates 13 as shown in fig. 3, cleaning by means of blow-back using compressed gas is possible.

The screen 13 may be fixed to the rotary shaft 8 and may be in dynamic seal engagement with the casing 2, or may be fixed to the inner surface of the casing 2 and may be in dynamic seal engagement with the rotary shaft 8, and the former is preferable.

In some embodiments, if the pin has a blade structure to generate the blowing effect when a given angle is formed between the pin and the fixing plate, and a screen plate 13 is provided outside the fixing plate on the blowing direction side, the pin is slightly long, and even if a round pin is used, the blowing force is generated due to the pin having an angle with the revolution axis.

Further, for applications where the impeller 14 is not separately provided, the pins may be finned from a cylindrical base to provide greater air flow capacity.

It will be appreciated that, due to the high speed of rotation of the rotor, even with the shorter fins provided on the pins, a relatively large wind force will still be generated.

Further, as for the given angle, it is not preferable to be too large as described above, and it is preferable to select the given angle to be 85 to 89 degrees.

In the foregoing, it is pointed out that, because of the different installation manners of the pins, in the embodiment of the present invention, there is enough installation space in the radial direction of the housing 2, and the pins can be installed in multiple layers. In the preferred embodiment the pins have two annular arrays on the rotor, forming an outer pin array on the centrifugal side of the housing 2 and an inner pin array on the centripetal side of the housing, the corresponding rotor constituting a double-layer pin-type rotor.

When the particle size of the material entering from the feed hopper 5 is large and the speed is high, the situation that a large amount of powder is accumulated in the shell 2 may occur, at this time, part of the powder passes through the outer pin array, and at this time, the powder collides with the inner pin array and rebounds to the outer pin or the lining plate 11 to be crushed; or when the material is less and the wind speed generated by the rotor is higher, the centrifugal force can roll part of the powder into the inner pin rod array, and the powder can be crushed for two or more times.

Preferably, the outer pin array is located at a radial end of the rotor; the inner pin array is located at the position two thirds R-three quarters R of the radial distance from the axis of the rotor;

wherein R is the radius of the reference circle of the outer pin array.

Preferably, the number of the inner pins 16 included in the inner pin array is 2 times the number of the outer pins 17 included in the outer pin array, and thus excellent pulverization effect is obtained.

As for the pulverization of the ultrafine powder mill, one is the impact by a pin, and the other is the impact by the inner surface of the casing or the back-impact by the lining plate 11 as shown in fig. 3. The housing 2 is required to have high strength and high individual cost, and is not suitable for frequent replacement, and the lining plate 11 may have a small thickness and relatively low cost, and may be made of a material having high hardness and relatively poor properties, such as cast iron, so that the lining plate 11 may be installed in the housing 2 to improve the overall maintainability.

Preferably, the lining plate 11 is formed by splicing a plurality of arc-shaped lining plate blocks and can be independently replaced.

Accordingly, the arc-shaped lining blocks are fixed on the inner surface of the shell 2 by screws 4 interposed outside the shell 2, i.e., the fitting structure of the arc-shaped lining blocks belongs to a fitting structure which can be independently replaced.

The arc-shaped liner block preferably has a central angle of 30 degrees.

In the configuration shown in fig. 3, the bottom of the feed hopper 5 is adapted to the feed opening opened at the upper side of the housing 2, and a filter sieve 12 is installed at the feed opening to prevent the excessively large material from entering the crushing chamber 7, thereby preventing the accumulation in the crushing chamber 7.

On the right side of fig. 3, the sieve plate 13 is spaced apart from the end plate on the side where it is located by a settling distance, which is referred to as the diameter of the inner cylindrical surface of the housing 2, and which is not less than one eighth of the inner cylindrical surface of the housing 2, and generally not more than one half of the inner cylindrical surface of the housing 2.

Accordingly, the discharge port 20 is located at the lower portion of the end plate, that is, the lower portion of the rear end plate 6 in fig. 3.

Claims

1. An ultrafine powder mill, comprising:

2. The ultrafine powder mill according to claim 1, wherein the pins have two annular arrays on the rotor, forming an outer pin array on the centrifugal side and an inner pin array on the centripetal side.

3. The ultrafine powder mill as set forth in claim 2, wherein the outer pin arrays are located at the radial ends of the rotor;

wherein R is the radius of the reference circle of the outer pin array.

4. The ultrafine powder mill according to claim 2 or 3, wherein the number of inner pins is 2 times the number of outer pins.

5. The ultrafine powder mill according to claim 1, wherein the predetermined angle is 85 to 89 degrees.

6. The ultrafine powder mill as claimed in claim 1, wherein the inner cylindrical surface of the housing is provided with a lining plate.

7. The ultrafine powder mill according to claim 6, wherein the lining plate is formed by splicing a plurality of arc-shaped lining plate blocks;

8. The ultrafine powder mill according to claim 1, wherein the bearing is a magnetic suspension bearing;

the motor distributed by the driver is a magnetic suspension motor.

9. The ultrafine powder mill as claimed in claim 1, wherein the feed inlet is equipped with a filter screen.

10. The ultrafine powder mill according to claim 1, wherein a settling distance is provided between the sieve plate and the end plate on the side where the sieve plate is located;

the discharge port is positioned at the lower part of the end plate.