Multi-stage variable-speed spiral conveying mechanism and anti-caking and anti-blocking method thereof

Abstract

The invention discloses a multi-stage variable-speed spiral conveying mechanism and an anti-caking and anti-blocking method thereof. A conveying rotating shaft is in transmission connection with a multi-stage variable-rotating-speed power mechanism; an air inlet is formed in the lower side, close to the feeding hole, of the outer barrel; pressure sensors are evenly distributed on the upper side and the lower side of the outer cylinder and are in signal connection with a controller, and the controller is in signal connection with the multi-stage variable-rotating-speed power mechanism and the air inlet mechanism. During operation, high-pressure air is input into the material, and the air pressure of each section of the outer barrel is monitored. The technical scheme has the beneficial effects that high-pressure air is conveyed into the outer barrel according to the description of the technical scheme, so that the pressure of materials at each section of the inner cavity of the outer barrel is balanced, and conditions are formed for constant-speed feeding, constant-speed conveying and constant-speed discharging; high air pressure exists among the material particles, and the material particles are difficult to be too compact due to the pressure of the conveying spiral blades; and precipitation and evaporation of moisture in the materials can be reduced, and caking and dry hardening are prevented.

Description

Technical Field

[0001] This invention relates to the field of anti-caking technology for screw conveyors, and in particular to a multi-stage variable speed screw conveyor mechanism and its anti-caking and clogging method. Background Technology

[0002] Screw conveyors are widely used in industries such as chemical, building materials, food, and environmental protection (e.g., sludge treatment) for conveying powders, granules, or viscous materials with high moisture content due to their compact size and ease of use in enclosed conveying. However, when used in enclosed conveying, materials with high moisture content or high viscosity are prone to agglomeration and blockage. During conveying, the screw blades continuously tumble the material, creating a mixing effect that compresses moisture from the powder and increases its density, causing powder that wouldn't normally agglomerate to clump. Furthermore, the friction from this compression raises the material's temperature, causing the moisture in the initially flexible clumps to evaporate, resulting in hardened, dry clumps and further blockages.

[0003] A screw conveyor mechanism, disclosed in CN109422075A, employs two structures to prevent blockage in the middle section of the screw conveyor. One structure uses a U-shaped cross-section for the conveyor cylinder to create a larger buffer space. However, when conveying materials upwards, due to gravity, highly fluid materials still tend to occupy the U-shaped space, thus negating the intended purpose of increasing the volume to provide buffer space. The other structure involves notches at the edges of the screw blades, allowing some material to flow out when accumulation occurs. However, these notches result in material leakage even without accumulation, impairing the efficiency of upward conveying. Furthermore, the area before the notch forms agitating teeth, increasing the agitation of the conveyed material and further exacerbating agglomeration.

[0004] A screw conveyor with publication number CN117566351A discloses an anti-caking screw conveyor. It features a threaded rod parallel to the shaft of the screw blades. The threaded rod is movably connected to a slider, a cleaning block, and a cleaning strip. The slider is also connected to a spray pipe for water spraying. When cleaning is required, the spray pipe, cleaning block, and cleaning strip move along the threaded rod to perform cleaning, preventing material buildup and blockage in the conveyor cylinder. However, this cleaning process requires interrupting the conveying operation, affecting its efficiency. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a multi-stage variable speed screw conveyor mechanism and its method for preventing caking and blockage. High-pressure air is delivered into the outer cylinder to balance the pressure of materials in different sections of the inner cavity, creating conditions for uniform feeding, conveying, and discharging. The high air pressure between material particles also makes it difficult for the material particles to become too dense due to the pressure of the conveying screw blades. Furthermore, it reduces the evaporation of moisture in the material, preventing caking and hardening.

[0006] To achieve the above objectives, the present invention provides a multi-stage variable speed screw conveyor mechanism, including an outer cylinder, a conveying shaft movably disposed in the inner cavity of the outer cylinder, and conveying screw blades connected around the conveying shaft.

[0007] The conveying shaft is connected to a multi-stage variable speed power mechanism.

[0008] The outer cylinder is provided with a feed inlet and a discharge outlet. An air inlet is provided on the lower side of the outer cylinder near the feed inlet and is connected to an air intake mechanism.

[0009] Several pressure sensors are provided on both the upper and lower sides of the outer cylinder. The pressure sensor signals are connected to a controller, and the controller signals are connected to the multi-stage variable speed power mechanism and the air intake mechanism.

[0010] Furthermore, the conveying spiral blade includes a first blade segment and a second blade segment, wherein the first blade segment is located between the air inlet and the feed inlet, and the second blade segment is located between the air inlet and the discharge outlet;

[0011] The pitch of the first leaf segment is smaller than that of the second leaf segment;

[0012] The pitch of the second leaf segment gradually increases from the inlet to the outlet.

[0013] Furthermore, the feed inlet includes a funnel section and a first vertical section, the first vertical section being located between the funnel section and the outer cylinder;

[0014] The discharge port includes a buffer section and a second vertical section, wherein the buffer section is located between the second vertical section and the outer cylinder.

[0015] The buffer section gradually increases in cross-section from the point where it connects to the second vertical section to the point where it connects to the outer cylinder, and the buffer section is provided with a slope that slopes downward from the outer cylinder to the second vertical section.

[0016] Furthermore, an anti-bridging mechanism is provided at the connection between the buffer section and the second vertical section. The anti-bridging mechanism includes an anti-bridging pivot, and the anti-bridging pivot is connected to an anti-bridging blade.

[0017] Furthermore, a scraper is connected to the side of the conveying spiral blade facing away from the conveying direction. The scraper includes a first scraping part parallel to the axis of the outer cylinder and a second scraping part facing the working surface of the conveying spiral blade. The first scraping part, the second scraping part, the back side of the conveying spiral blade, and the conveying shaft are completely enclosed.

[0018] Furthermore, the first scraper and the second scraper are configured to be serrated.

[0019] Furthermore, a temperature sensor is provided on the lower side of the outer cylinder, and the temperature sensor signal is connected to the controller.

[0020] Furthermore, an inner cylindrical hole is provided on the upper side of the outer cylinder, and the inner cylindrical hole is connected to the pressure sensor, so that a gap preventing material interference is formed between the upper side of the outer cylinder and the pressure sensor.

[0021] A method for preventing material caking and clogging in a multi-stage variable speed screw conveyor mechanism includes the following steps:

[0022] Step 1: Send a start command to the controller.

[0023] The controller activates the intake mechanism, and the intake pressure is set to one of the set pressures.

[0024] The controller controls the multi-stage variable speed power mechanism to start up to the set speed, and feeds material through the feed port, so that the material is isolated from the outer cylinder and the outside world through the feed port; the conveyor blades convey part of the material to the discharge port, so that the material is isolated from the outer cylinder and the outside world through the discharge port;

[0025] During this process, since the conveying spiral blade speed is at a low level, if the material parameters are qualified and the equipment is normal, there will be no caking or blockage.

[0026] Step 2: When the pressure monitored by each pressure sensor reaches the set air pressure one, the controller controls the increase of the intake air pressure to the set air pressure two;

[0027] The controller controls the multi-stage variable speed power mechanism to increase its speed to the set speed.

[0028] The anti-bridging mechanism is activated, and material begins to flow from the discharge port;

[0029] Step 3: When the pressure sensors on the upper side of the outer cylinder detect excessively rapid pressure release, the anti-bridging mechanism is shut off until the detected pressure rises back to the set pressure.

[0030] The controller uses the pressure difference monitored by the pressure sensors on the upper and lower sides of the same section of the outer cylinder as a parameter to calculate the material density of each section of the inner cavity of the outer cylinder.

[0031] The controller uses the pressure difference monitored by adjacent pressure sensors on the upper side of the outer cylinder as a parameter to determine whether blockage has occurred between different sections of the outer cylinder;

[0032] Step 4: If the material is compressed too much or has too high a density, reduce the feeding speed and reduce the speed of the multi-stage variable speed power mechanism.

[0033] If the pressure difference between adjacent pressure sensors on the upper side of the outer cylinder increases, the feeding speed will be reduced, and the speed of the multi-stage variable speed power mechanism will be reduced.

[0034] The beneficial effects of this solution can be understood from the description of the above solution, and it has the following advantages:

[0035] (1) High-pressure air is delivered into the outer cylinder to balance the pressure of materials in different sections of the outer cylinder, preventing excessive pressure differences between different sections, thus creating conditions for uniform feeding, uniform conveying and uniform discharging.

[0036] (2) High-pressure air is delivered into the inner cavity of the outer cylinder, so that there is a high air pressure between the material particles. Therefore, the pressure of the conveying spiral blade is also less likely to make the material particles too dense, reducing the possibility of material particles sticking together due to compression.

[0037] (3) Due to the screw conveyor, not only will the material be squeezed, but the temperature of the material will also rise. High-pressure air is delivered into the outer cylinder, which can reduce the precipitation of moisture in the material, thereby reducing the possibility of caking; it can also reduce the evaporation of moisture in the material, preventing the formation of dry and hard lumps, which are easy to cause blockage.

[0038] (4) High-pressure air is supplied from near the feed inlet. Since the high-pressure air will inevitably be lost from the discharge outlet along with the material, the pressure sensor data of different sections on the upper side of the outer cylinder can be used to determine whether the airflow is smooth, thereby determining whether a blockage has occurred and the location of the blockage.

[0039] (5) The greater the pressure inside the outer cylinder, the easier it is for the material to stick to the outer cylinder and the conveying spiral blade. Therefore, high-pressure air is conveyed from below the material to form high-pressure air in the gap between the material from the beginning, thereby balancing the pressure inside and outside the material and avoiding the aggravation of adhesion caused by high-pressure gas.

[0040] (6) The shape of the inlet and outlet is designed to facilitate the formation of a closed high-pressure gas space in the outer cylinder;

[0041] (7) The spacing between the first leaf segments is smaller than that between the second leaf segments, which can better prevent high-pressure gas from overflowing from the feed inlet; and since the extrusion of the material near the feed inlet has just begun, the spacing between the first leaf segments is smaller, which will make the spacing between the second leaf segments relatively larger. If the first leaf segments do not clump, the clumping of the second leaf segments may also be reduced.

[0042] (8) The discharge port is equipped with an anti-bridging mechanism, which can effectively prevent bridging at the discharge port and also help to form material accumulation at the discharge port, helping the outer cylinder to form a high-pressure gas space.

[0043] (9) A scraper is installed so that when the inner wall of the outer cylinder forms a clump of material, if the clump becomes larger and extends from the working surface of the conveying spiral blade to the back of the front conveying spiral blade, the scraper will cut the clump of material to prevent the clump of material from blocking the gap of the conveying spiral blade.

[0044] (10) During the conveying process of the conveying spiral blade, the material will be stirred. Some existing technologies welcome this stirring effect and even intentionally set up technical features that are conducive to stirring. However, stirring will undoubtedly cause the material particles to release water and increase viscosity, which can easily lead to the formation of agglomerates. The first scraper, the second scraper, the back of the conveying spiral blade and the conveying shaft are completely sealed. During the process of cutting the material, the stirring of the material is minimized. At the same time, since the rotation speed of the scraper is greater than the rotation speed of the material, it is beneficial to form a gap between the front and rear conveying spiral blades.

[0045] (11) The scraper is set to be serrated, which will not form a smooth cut on the agglomerated clumps, but will pull the agglomerated clumps, so that the surface of the clumps will form many gaps that can accommodate air, which is conducive to the loosening of the material. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of the present invention.

[0047] Figure 2 This is a schematic diagram of the structure of the spiral conveyor blade of the present invention.

[0048] Figure 3 for Figure 2 Enlarged view of part I.

[0049] Figure 4 for Figure 3 A schematic diagram of another embodiment of the location.

[0050] In the diagram, 1. Outer cylinder; 1-1. Inner cylindrical cavity; 1-2. Anti-material interference gap; 2. Feed inlet; 2-1. Funnel section; 2-2. First vertical section; 3. Discharge outlet; 3-1. Buffer section; 3-2. Second vertical section; 3-3. Slide; 4. Anti-bridging mechanism; 4-1. Anti-bridging shaft; 4-2. Anti-bridging blade; 5. Conveying shaft; 6. Conveying spiral blade; 6-1. First blade segment; 6-2. Second blade segment; 7. Multi-stage variable speed power mechanism; 8. Air inlet; 9. Pressure sensor; 10. Temperature sensor; 11. Scraper; 11-1. First scraper section; 11-2. Second scraper section. Detailed Implementation

[0051] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0052] like Figure 1As shown, this embodiment is a multi-stage variable speed screw conveyor mechanism and its anti-clogging method, including an outer cylinder 1, with an inlet 2 and an outlet 3. The inlet 2 includes a funnel section 2-1 and a first vertical section 2-2, with the first vertical section 2-2 located between the funnel section 2-1 and the outer cylinder 1. The outlet 3 includes a buffer section 3-1 and a second vertical section 3-2, with the buffer section 3-1 located between the second vertical section 3-2 and the outer cylinder 1. The cross-section of the buffer section 3-1 gradually increases from the point connecting to the second vertical section 3-2 to the point connecting to the outer cylinder 1, and the buffer section 3-1 is provided with a slope 3-3 that slopes downward from the outer cylinder 1 to the second vertical section 3-2. An anti-bridging mechanism 4 is provided at the connection between the buffer section 3-1 and the second vertical section 3-2. The anti-bridging mechanism 4 includes an anti-bridging shaft 4-1, with anti-bridging blades 4-2 connected to the anti-bridging shaft 4-1.

[0053] A conveying shaft 5 is movably mounted inside the outer cylinder 1. A conveying spiral blade 6 is connected around the conveying shaft 5. The conveying spiral blade 6 includes a first blade segment 6-1 and a second blade segment 6-2. The first blade segment 6-1 is located between the air inlet 8 and the feed inlet 2, and the second blade segment 6-2 is located between the air inlet 8 and the discharge outlet 3. The pitch of the first blade segment 6-1 is smaller than that of the second blade segment 6-2. The pitch of the second blade segment 6-2 gradually increases from the feed inlet 2 to the discharge outlet 3. The conveying shaft 5 is driven by a multi-stage variable speed power mechanism 7.

[0054] An air inlet 8 is provided on the lower side of the outer cylinder 1 near the feed inlet 2 and is connected to an air intake mechanism.

[0055] Pressure sensors 9 are evenly distributed on both the upper and lower sides of the outer cylinder 1. The pressure sensors 9 are connected to a controller, which in turn is connected to a multi-stage variable speed power mechanism 7 and an air intake mechanism. An inner cylinder 1-1 is located on the upper side of the outer cylinder 1, and the pressure sensors 9 are connected to it, creating a gap 1-2 between the upper side of the outer cylinder 1 and the pressure sensors 9 to prevent material interference. A temperature sensor 10 is located on the lower side of the outer cylinder 1, and its signal is connected to the controller.

[0056] like Figure 2 , 3 As shown, a scraper 11 is connected to the side of the conveying spiral blade 6 facing away from the conveying direction. The scraper 11 includes a first scraper part 11-1 parallel to the axis of the outer cylinder 1 and a second scraper part 11-2 facing the working surface of the conveying spiral blade 6. The first scraper part 11-1, the second scraper part 11-2, the back surface of the conveying spiral blade 6, and the conveying shaft 5 are completely sealed. When a clump of material adheres to the inner wall of the outer cylinder 1, if the clump becomes large and extends from the working surface of the conveying spiral blade to the back surface of the front conveying spiral blade, the scraper 11 will cut the clump to prevent it from clogging the gap of the conveying spiral blade.

[0057] like Figure 4 As shown, in another embodiment, the first scraper 11-1 and the second scraper 11-2 are set in a serrated shape. Although this makes maintenance and cleaning more troublesome, the serration can avoid forming smooth cuts on the agglomerated material clumps. Instead, it will pull the agglomerated material clumps, so that the surface of the clumps forms many gaps that can accommodate air, preventing the formation of dense agglomerated material clumps that are prone to clogging.

[0058] A multi-stage variable speed screw conveyor mechanism and its anti-caking and clogging method include the following steps:

[0059] Step 1: Send a start command to the controller, and the controller will start the air intake mechanism with the air intake pressure set to the set pressure.

[0060] The controller controls the multi-stage variable speed power mechanism to start up to the set speed, and feeds material through the feed port, so that the material is isolated from the outer cylinder and the outside world through the feed port; the conveyor blades convey part of the material to the discharge port, so that the material is isolated from the outer cylinder and the outside world through the discharge port;

[0061] During this process, since the conveying spiral blade speed is at a low level, if the material parameters are qualified and the equipment is normal, there will be no caking or blockage.

[0062] Step 2: When the pressure monitored by each pressure sensor reaches the set air pressure one, the controller controls the increase of the intake air pressure to the set air pressure two;

[0063] The controller controls the multi-stage variable speed power mechanism to increase its speed to the set speed.

[0064] The anti-bridging mechanism is activated, and material begins to flow from the discharge port;

[0065] Step 3: When the pressure sensors on the upper side of the outer cylinder detect excessively rapid pressure release, the anti-bridging mechanism is shut off until the detected pressure rises back to the set pressure.

[0066] The controller uses the pressure difference monitored by the pressure sensors on the upper and lower sides of the same section of the outer cylinder as a parameter to calculate the material density of each section of the inner cavity of the outer cylinder.

[0067] The controller uses the pressure difference monitored by adjacent pressure sensors on the upper side of the outer cylinder as a parameter to determine whether blockage has occurred between different sections of the outer cylinder;

[0068] Step 4: If the material is compressed too much or has too high a density, reduce the feeding speed and reduce the speed of the multi-stage variable speed power mechanism.

[0069] If the pressure difference between adjacent pressure sensors on the upper side of the outer cylinder increases, the feeding speed will be reduced, and the speed of the multi-stage variable speed power mechanism will be reduced.

[0070] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A multi-stage variable speed auger conveyor mechanism, characterized by, The outer cylinder is internally movably provided with a conveying shaft, and a conveying spiral blade is connected around the conveying shaft; The conveying shaft is drivingly connected with a multi-stage variable speed power mechanism; The outer cylinder is provided with a feeding port and a discharging port, and an air inlet is arranged on the lower side of the outer cylinder close to the feeding port and is communicated with an air inlet mechanism; The upper and lower sides of the outer cylinder are both provided with a plurality of pressure sensors, and the pressure sensors are signal-connected with a controller, and the controller is signal-connected with the multi-stage variable speed power mechanism and the air inlet mechanism.

2. A multi-stage variable speed screw conveyor mechanism according to claim 1, wherein, The conveying spiral blade comprises a first blade segment and a second blade segment, the first blade segment is located between the air inlet and the feeding port, and the second blade segment is located between the air inlet and the discharging port; The pitch of the first blade segment is smaller than that of the second blade segment; The pitch of the second blade segment gradually increases from the feeding port to the discharging port.

3. A multi-stage variable speed screw conveyor mechanism according to claim 1, wherein, The feeding port comprises a funnel segment and a first vertical segment, and the first vertical segment is located between the funnel segment and the outer cylinder; The discharging port comprises a buffer segment and a second vertical segment, and the buffer segment is located between the second vertical segment and the outer cylinder; The buffer segment gradually increases in cross section from the connection with the second vertical segment to the connection with the outer cylinder, and the buffer segment is provided with a landslide that is inclined downward from the outer cylinder to the second vertical segment.

4. A multi-stage variable speed screw conveyor mechanism according to claim 3, wherein, A bridge prevention mechanism is arranged at the connection between the buffer segment and the second vertical segment, and the bridge prevention mechanism comprises a bridge prevention shaft, and the bridge prevention shaft is connected with a bridge prevention blade.

5. A multi-stage variable speed screw conveyor mechanism according to claim 1, wherein, A scraping piece is connected to one side of the conveying spiral blade in the direction opposite to the conveying direction, the scraping piece comprises a first scraping part parallel to the axis of the outer cylinder, the scraping piece comprises a second scraping part facing the working surface of the conveying spiral blade, and the first scraping part, the second scraping part, the back surface of the conveying spiral blade and the conveying shaft are completely closed.

6. A multi-stage variable speed screw conveyor mechanism according to claim 4, wherein, The first scraping part and the second scraping part are provided in a zigzag shape.

7. A multi-stage variable speed screw conveyor mechanism as claimed in claim 1, wherein, A temperature sensor is arranged on the lower side of the outer cylinder, and the temperature sensor is signal-connected with the controller.

8. A multi-stage variable speed screw conveyor mechanism according to claim 1, wherein, An inner hole cylinder is arranged on the upper side of the outer cylinder, the inner hole cylinder is connected with the pressure sensor, and a material interference gap is formed between the upper side of the outer cylinder and the pressure sensor.

9. A method of preventing material blocking in a multi-stage variable speed screw conveyor, characterized by, The method comprises the following steps: Step 1: issuing a start instruction to the controller, the controller controls the air inlet mechanism to start, the air inlet pressure is set pressure one; The controller controls the multi-stage variable speed power mechanism to start to set speed one, and the material is put into the feeding port, so that the material is separated from the outer cylinder and the outside world by the feeding port; the conveying blade conveys part of the material to the discharging port, so that the material is separated from the outer cylinder and the outside world by the discharging port; In this process, since the conveying spiral blade has a low speed, if the material parameters are qualified and the equipment is normal, material accumulation and blockage will not occur; Step 2: when the pressure monitored by each pressure sensor reaches set pressure one, the controller controls the air inlet pressure to increase to set pressure two; The controller controls the multi-stage variable speed power mechanism to increase the speed to set speed two; The bridge prevention mechanism is started, and the discharging port starts to discharge; Step 3: when the pressure sensor on the upper side of the outer cylinder detects that the pressure relief is too fast, the bridge prevention mechanism is closed until the detected pressure rises to set pressure two again. The controller takes the pressure difference monitored by the upper and lower pressure sensors on the same section of the outer cylinder as a parameter for calculating the compactness of the material in the inner cavity of the outer cylinder; The controller takes the pressure difference monitored by the adjacent pressure sensors on the upper side of the outer cylinder as a parameter for judging whether a blockage occurs between the sections of the outer cylinder; Step 4: If the extrusion degree of the material at a certain place is too large, or the compactness is too large, the feeding speed is reduced, and the multi-stage variable speed power mechanism is reduced in speed. If the pressure difference of the adjacent pressure sensors on the upper side of the outer cylinder increases, the feeding speed is reduced, and the multi-stage variable speed power mechanism is reduced in speed.

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