A particle separation device based on spiral conveying

Abstract

The present invention discloses a particle separation device based on spiral conveying, comprising a material inlet, a spiral conveyor, and a material outlet collection device. The spiral conveyor comprises a pipe wall, dragon blades, and an inner shaft tube. The inner shaft tube is divided into three sections. The first section is a solid shaft with a smaller diameter, close to the material inlet, connected to a motor to provide rotational power. The second section is a hollow portion. Removing the inner shaft tube allows sufficient space for large particles to fall. The third section is a thin-walled pipe for a large particle collection device. The dragon blades are divided into three sections corresponding to the inner shaft tube. The first section connects to the solid shaft and has a wider blade. The second section gradually narrows the blade, providing sufficient space for large particles to fall. The third section connects to the thin-walled pipe of the large particle collection device and has the narrowest blade. This device achieves the separation and separate collection of large and small particles. The device has the advantages of continuous operation, high degree of automation, and large single-machine processing capacity, and has important engineering application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of spiral separation, and in particular relates to a device for separating particles based on spiral conveying. Background Art

[0002] Screw conveyors are widely used in various sectors of the national economy, including the grain industry, building materials industry, chemical industry, machinery manufacturing, and transportation. They are primarily used to transport a variety of powdered, granular, and small-block materials. Bulk materials transported include grains, beans, and flour; building materials such as cement, clay, and sand; chemicals such as salts, alkalis, and fertilizers; and bulk cargoes such as coal, coke, and ore. In addition to transporting bulk materials, screw conveyors can also be used to transport various piece items. While conveying materials, screw conveyors can also perform operations such as mixing, stirring, and cooling.

[0003] Spiral separation technology is a method of separating particles by high-speed rotation, which generates different centrifugal forces for particles of different properties. Spiral separation has the advantages of continuous operation, high degree of automation, large single-machine processing capacity, and strong adaptability to materials. Currently, spiral separation technology is mostly used in solid-liquid separation, gas-liquid separation, oil-water separation, etc., and its application in solid-solid separation is limited. However, in engineering, the need for separation of cement powder and quartz sand is not uncommon. Therefore, it is extremely urgent to develop a separation method based on a screw conveyor that can be widely applied to various solid particles and is easy to use in practice.

[0004] During the actual research on screw conveyor-based separation methods, a phenomenon known as the "annular Brazil nut effect" emerged. The separation of particles of different sizes caused by vertical mechanical vibration is a common particle stratification phenomenon. Typically, larger particles migrate to the upper layer of the bed during vibration, while smaller particles migrate to the lower layer. This stratification phenomenon is known as the "annular Brazil nut effect." The "annular Brazil nut effect" is a "Brazil nut" separation configuration in which large particles are distributed in the upper layer and smaller particles in the lower layer within a circular ring of a rotary motion device. The area near the center of the ring is entirely composed of large particles. Summary of the Invention

[0005] Aiming at the shortcomings of the existing technology, a particle separation device based on spiral conveying is proposed, which is suitable for separating small solid particles such as cement powder and quartz sand.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A particle separation device based on spiral conveying includes a material inlet, a spiral conveyor and a material outlet collection device. The spiral conveyor includes a pipe wall, dragon blades and an inner shaft tube. The inner shaft tube is divided into three sections. The first section is a solid shaft with a smaller diameter, close to the material inlet, and serves as the part connected to the motor to provide rotational power. The second section is a hollow part. Removing the inner shaft tube allows large particles to have sufficient space to fall. The third section is a thin-walled pipe of a large particle collection device. The dragon blades are divided into three sections corresponding to the inner shaft tube. The first section is connected to the solid shaft and has a wider blade. The second section gradually narrows the blade to provide large particles with sufficient space to fall. The third section is connected to the thin-walled pipe of the large particle collection device and has the narrowest blade.

[0008] Furthermore, the material outlet collecting device includes the large particle collecting device and the small particle collecting device. The large particle collecting device is an added thin-walled pipe, into which large particles falling from the central area can fall under the action of gravity; the small particle collecting device is a bucket-shaped material outlet added to the tail of the screw conveyor.

[0009] Furthermore, the inner diameter of the screw conveyor ranges from 630mm to 1000mm, and the diameter of the first section of the inner tube shaft ranges from 168mm to 267mm.

[0010] Furthermore, the screw conveyor has a fixed pitch ranging from 450mm to 715mm, and the thickness of the Jiaolong blade ranges from 2mm to 5mm.

[0011] Furthermore, the total length of the screw conveyor is determined by the number of turns of the Jiaolong blade, and the total length is the screw conveyor diameter Ø*5*number of turns / 7, and the pipe wall thickness ranges from 2mm to 5mm.

[0012] Furthermore, the rotation speed of the screw conveyor is 60-140 rpm.

[0013] Furthermore, the inner diameter of the thin-walled pipe is 225mm-260mm.

[0014] Furthermore, the ratio of the particle sizes of large particles to small particles in the separated material is greater than 5:1.

[0015] The present invention also provides a particle separation method based on spiral conveying, which is carried out using the particle separation device described above, and includes the following steps: starting the equipment, and the material to be separated enters the spiral conveying pipe from the material inlet. The spiral conveying in the spiral conveying pipe is divided into three sections from top to bottom. In the first stage, the dragon blades and the inner shaft tube with a smaller diameter are connected together. Due to the high-speed rotation of the spiral conveying, the materials of different particle sizes are separated by rotation, and the large particles gather in the central area, and the small particles are distributed in the pipe wall area. After reaching a certain stable state, it then enters the second stage. In the second stage, the inner shaft tube is removed, the width of the dragon blades is further reduced, and the middle part is hollow. The large particles Small particles fall from the middle and continue to rotate along with the Jiaolong blades, thereby achieving an effective separation effect. Finally, it enters the third stage. A thin-walled pipe for collecting large particles is set in the center of the tail pipe. The width of the Jiaolong blades is further reduced and connected to the thin-walled pipe. The large particles in the central area fall into the thin-walled pipe under the action of gravity and leave the spiral conveying separation device through this pipe. A material outlet for collecting small particles is set on the outer wall of the spiral conveyor tail. The small particles are affected by the "annular Brazil nut effect" and gather on the outer pipe wall. Under the action of centrifugal force, the small particles will leave the spiral conveying separation device through the set material outlet, thereby realizing the separation and separate collection of large and small particles.

[0016] Beneficial effects

[0017] The present invention discloses a particle separation device based on a spiral conveyor, comprising unequal diameter dragon blades, a truncated inner tube, and a device for separating and collecting large and small particles. The high-speed rotation of the spiral conveyor generates centrifugal forces of varying magnitude for particles of varying properties, achieving initial separation of the particles due to the varying forces. Furthermore, high-speed rotating devices such as spiral conveyors can also experience a "ring-shaped Brazil nut effect," whereby large particles accumulate in the center of the tube after rotational separation, while small particles are distributed along the tube walls.

[0018] Based on the above conditions, the present invention proposes that after a certain period of time and distance of separation in a screw conveyor, the particles reach a stable separation state. The inner shaft tube is then removed at the current position, and the dragon blades are gradually narrowed until large particles can fall smoothly, allowing them to fall into the central hollow area while small particles continue to rotate with the dragon blades, thereby achieving effective separation. After large and small particles are separated, a thin-walled pipe is installed at the center of the tail pipe to collect large particles. Large particles in the central area fall into this pipe under the action of gravity and exit the screw conveyor separation device through this pipe. A material outlet is provided on the outer wall of the screw conveyor separation device to collect small particles. Small particles, influenced by the "annular Brazil nut effect," accumulate on the outer pipe wall. Under the influence of centrifugal force, small particles exit the screw conveyor separation device through the provided outlet, thus achieving separation and separate collection of large and small particles. Simulations using domestic discrete element analysis software are also performed to determine the horizontal distribution of large and small particles at each moment, as well as the length of the pipe where the separation of large and small particles reaches a stable state, thereby determining the parameters for customizing the screw conveyor separation (the inner diameter of the dragon blades and the length of the inner pipe at the head and tail). This device has the advantages of continuous operation, high degree of automation, and large single-machine processing capacity, and has important engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a screw conveying device commonly used in engineering in the prior art;

[0020] Figure 2 It is a three-view structural diagram of the screw conveying device of the present invention;

[0021] Figure 3 Schematic cross-sectional view of the material inlet of the spiral conveying and separating device of the present invention;

[0022] Figure 4 is a cross-sectional schematic diagram of a small particle collection device of the present invention;

[0023] Figure 5-7 It is a top view of a local spiral conveying and separating device at different heights;

[0024] Figure 8 Simulation by discrete element analysis software: distribution diagram of small particles at the device inlet at simulation time of 3s;

[0025] Figure 9 Simulated by discrete element analysis software: distribution diagram of small particles at the device inlet at simulation time 19s;

[0026] Figure 10 is the average distance between particles of different sizes in the spiral conveying tube and the axis;

[0027] Figure 11 It is the average distance between particles of different sizes and the axis in the spiral conveying tube. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. It is obvious that the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatuses.

[0030] The screw conveyor devices commonly used in engineering can be found in Figure 1 The present invention redesigns several aspects of conventional screw conveyors. After the high-speed rotation of the screw conveyor, particles of varying properties generate varying centrifugal forces, leading to initial separation. Furthermore, high-speed rotating devices like screw conveyors can produce a phenomenon known as the "ring-shaped Brazil nut effect," whereby large particles accumulate in the center of the tube and smaller particles are distributed along the tube walls.

[0031] According to this phenomenon, the present invention has redesigned the inner shaft tube. Figure 2 The three-view drawing of the designed spiral conveying and separation device shows that the inner shaft tube is no longer through the entire pipeline, but is divided into three sections. The first section is a solid shaft with a smaller diameter, which is the part connected to the motor to provide rotational power. The second section is a hollow part. The inner shaft tube is removed to allow large particles to have enough space to fall. The third section is a thin-walled pipe for the large particle collection device. At the same time, the corresponding Jiaolong blades are redesigned. The Jiaolong blades are not of equal diameter. After a certain conveying length, the Jiaolong blades will become narrower, that is, the Jiaolong blades are also divided into three corresponding sections. The first section is connected to the solid shaft, and the blades are wider. The blades in the second section gradually narrow, giving large particles enough space to fall. The third section is connected to the thin-walled pipe of the large particle collection device, and the blades are the narrowest. The large particle collection device is an additional thin-walled pipe, into which large particles falling from the central area can fall under the action of gravity. The small particle collection device is as follows Figure 4The figure shows a bucket-shaped material outlet installed at the tail of the spiral separator. Small particles are affected by the "annular Brazil nut effect" and gather near the tube wall. Under the action of centrifugal force, they leave the device through the material outlet. This achieves the separation and separate collection of large and small particles during transportation.

[0032] The reference parameters for the spiral conveying and separation device are as follows: the designed spiral conveying tube is a standard component with a diameter range of 630mm-1000mm. The ratio of inner tube diameter to diameter is 4:15. The wall thickness and dragon blade thickness are 2mm-5mm. The fixed pitch of the dragon blade is 5:7 with respect to diameter. The number of dragon blade turns can be customized, with the total length being Ø*5*number of turns / 7. The wall diameter is ر2mm. It is driven by a motor capable of providing a speed of 60-140rpm. The width of the dragon blade and the length of the solid inner tube are determined based on simulation results.

[0033] The specific connection is: the material enters from the material inlet on the upper left of the spiral conveying and separation device. The first section of the pipeline where the material enters is the pipeline of a conventional screw conveyor, that is, the equal-diameter dragon blades are connected to the solid inner shaft tube, and the inner shaft tube is connected to the motor that provides rotational power; the second section is a pipeline without an inner shaft tube, and the dragon blades gradually narrow; in the third section of the pipeline, the dragon blades return to equal diameter and are connected to the thin-walled pipe of the large particle collection device, and the outer wall of the spiral conveying and separation device is connected to the outlet of the small particle collection device.

[0034] Figure 1 This is a screw conveying device that is often used in engineering applications, and the screw conveying separation device designed in the present invention is based on this.

[0035] Figure 2 This is a three-view drawing of the designed spiral conveying and separating device. From this engineering drawing, the designed parts of the present invention, namely the three-section inner shaft tube and the dragon blades, as well as the collection device for large and small particles, can be intuitively and accurately shown. At the same time, the working form of the spiral conveying and separating device can also be shown.

[0036] Figure 3 This is a cross-sectional diagram of the material inlet, which accurately shows that when the material enters the spiral conveying separation device, the large and small particles are randomly distributed.

[0037] Figure 4 This is a cross-sectional diagram of the small particle collection device. It accurately illustrates how, after spiral conveying and separation, large particles fall into the thin-walled pipe in the center. Small particles, influenced by the "annular Brazil nut effect," gather on the outer wall of the spiral conveying and separation device under centrifugal force and exit the device through the material outlet located there.

[0038] Figure 5-7These are top views of a partial spiral conveying and separation device at different heights. These images accurately demonstrate that the spiral conveying and separation device has multiple diameters of Jiaolong blades. After a certain distance of spiral conveying and separation, the Jiaolong blades gradually narrow, allowing large particles to have enough central area to fall into the thin-walled pipe at the tail, achieving separation and collection of large particles.

[0039] Figure 8 and Figure 9 Simulations using domestic discrete element analysis software show the distribution of small particles at the device inlet at 3 and 19 seconds. These two figures clearly show the random location of particle generation. By the time particle generation is complete, the small particles are distributed throughout the entire device cross-section. After a period of spiral conveying and separation in this device, the distribution of small particles in the central annular region significantly decreases, and the small particles accumulate near the wall, demonstrating a "ring-shaped Brazil nut effect," as expected.

[0040] Figure 10 and Figure 11 is the average distance between large and small particles and the axis in the spiral conveying tube. It can be clearly seen from the above two figures that the "annular Brazil nut effect" produced by spiral conveying cannot completely separate large and small particles. After a period of spiral separation, it will reach a certain stable state. The greater the difference in particle size, the shorter the time to reach the stable state.

[0041] After the spiral separation reaches a stable state, the structure inside the conveying pipe is changed, that is, the inner shaft tube is removed and the radius of the Jiaolong blade is reduced, so that the large particles in the center area fall directly, while the small particles gathered on the pipe wall continue to rotate with the Jiaolong blade, thereby achieving complete separation of large and small particles.

Claims

1. A particle separation device based on spiral conveying, comprising a material inlet, a spiral conveyor and a material outlet collecting device, wherein the spiral conveyor comprises a tube wall, dragon blades and an inner shaft tube, and is characterized in that: The inner shaft tube is divided into three sections. The first section is a solid shaft with a smaller diameter, which is located near the material inlet and connected to the motor to provide rotational power. The second section is a hollow part. The inner shaft tube is removed to allow large particles in the material to have enough space to fall. The third section is a thin-walled pipe for the large particle collection device. The diameter of the first section of the inner shaft tube ranges from 168mm to 267mm. The Jiaolong blade is divided into three sections corresponding to the inner shaft tube. The first section is connected to the solid shaft and has a wider blade. The second section gradually narrows to provide sufficient space for large particles to fall. The third section is connected to the thin-walled pipe of the large particle collection device and has the narrowest blade. The material outlet collection device includes a large particle collection device and a small particle collection device. The large particle collection device is a thin-walled pipe installed in the center area, and large particles falling from the central area can fall into it under the action of gravity; the small particle collection device is a bucket-shaped material outlet installed at the tail of the screw conveyor; The particle size ratio of large particles to small particles in the separated material is greater than 5:

1.

2. The particle separation device based on spiral conveying according to claim 1, characterized in that: The inner diameter of the screw conveyor ranges from 630mm to 1000mm.

3. The particle separation device based on spiral conveying according to claim 1, characterized in that: The fixed pitch of the screw conveyor ranges from 450mm to 715mm, and the thickness of the Jiaolong blade ranges from 2mm to 5mm.

4. The particle separation device based on spiral conveying according to claim 1, characterized in that: The total length of the screw conveyor is determined by the number of turns of the Jiaolong blade, and the total length is the screw conveyor diameter Ø*5*number of turns / 7, and the pipe wall thickness ranges from 2mm to 5mm.

5. The particle separation device based on spiral conveying according to claim 1, characterized in that: The rotation speed of the screw conveyor is 60-140 rpm.

6. The particle separation device based on spiral conveying according to claim 1, characterized in that: The inner diameter of the thin-walled pipe is 225 mm to 260 mm.

7. A particle separation method based on spiral conveying, characterized in that: The particle separation device according to any one of claims 1 to 6 is used, comprising the following steps: starting the equipment, the material to be separated enters the spiral conveying pipe from the material inlet, the spiral conveying in the spiral conveying pipe is divided into three sections from top to bottom, in the first stage, the Jiaolong blades and the inner shaft tube with a smaller diameter are connected together, due to the high-speed rotation of the spiral conveyor, the materials of different particle sizes are separated by rotation, the large particles gather in the central area, and the small particles are distributed in the pipe wall area, after reaching a certain stable state, it enters the second stage, in the second stage, the inner shaft tube is removed, the width of the Jiaolong blade is further reduced, the middle part is hollow, and the large particles fall from the middle, The small particles continue to rotate along with the Jiaolong blades, thereby achieving an effective separation effect, and finally enter the third stage. A thin-walled pipe for collecting large particles is set in the center of the tail pipe. The width of the Jiaolong blades is further reduced and connected to the thin-walled pipe. The large particles in the central area fall into the thin-walled pipe under the action of gravity and leave the spiral conveying separation device through this pipe. A material outlet for collecting small particles is set on the outer wall of the spiral conveyor tail. The small particles are affected by the "annular Brazil nut effect" and gather on the outer pipe wall. Under the action of centrifugal force, the small particles will leave the spiral conveying separation device through the set material outlet, thereby realizing the separation and separate collection of large and small particles.

Images