A non-standard chute design method for uniform screw movement of bulk materials

Abstract

The application discloses a non-standard chute design method for uniform screw movement of bulk materials, relates to the chute design field, and comprises a center column, a chute is spirally connected to the outer ring of the center column, a first step, a movement equation of the bulk materials on a three-dimensional curved surface in space is programmed and is converted into an Excel calculation program, a second step, known conditions are input into the calculation program, the known conditions comprise input of chute section types, curved surface parameters of the chute, material initial speed, feeding angle, friction coefficient data, a movement speed of the material is obtained by using the calculation program, and a third step, by comprehensive use of a function function of Excel and VBA programming, chute parameters need to be repeatedly adjusted for speed calculation in a scheme design stage.

Description

Technical Field

[0001] This invention relates to the field of chute design, and in particular to a non-standard chute design method for uniform spiral motion of bulk materials. Background Technology

[0002] In the coal market, the production costs of lump coal and fine coal are comparable, but their prices differ by 50% to 80%, sometimes even more than double. The profit per ton of coal can differ by about three times. Therefore, preventing breakage of lump coal is of great significance to coal enterprises. Broken lump coal typically experiences 30% to 40% breakage during storage and handling, a problem that has long plagued many coal companies.

[0003] For high-drop sections like coal bunkers, spiral chutes are commonly used to prevent coal breakage. Spiral chutes are three-dimensional spiral structures arranged along the bunker wall, typically designed in 2D using AutoCAD. Due to their complex spatial surface characteristics, the design and calculation workload for these chutes is substantial, and the drawing process is extremely tedious, consuming significant human resources for both design and verification. While 3D software design can save some calculation and drawing time, it still requires converting the design data into 3D before designing, and finally converting it back to 2D for factory processing. Therefore, it doesn't significantly improve work efficiency compared to AutoCAD 2D design. Furthermore, the impact force generated when transporting coal on the chute can cause breakage, and the instantaneous impact can also stir up dust, causing air pollution.

[0004] Therefore, it is necessary to propose a non-standard chute design method for uniform spiral motion of bulk materials to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a design method for non-standard chutes used for uniform spiral motion of bulk materials. This addresses the issue that spiral chutes, being spatial curved surface structures in the form of three-dimensional spirals arranged along the silo wall, are typically designed using AutoCAD in two dimensions. Due to the complex spatial surface characteristics of these chutes, the design calculations are extensive, the drawing process is cumbersome, and both design and verification consume significant human resources. While 3D software design can save some calculation and drawing time, it requires converting the design data into 3D before designing, and finally converting it back to 2D for factory processing. Therefore, it does not significantly improve work efficiency compared to AutoCAD 2D design.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a non-standard chute for uniform spiral motion of bulk materials, comprising support rods, wherein multiple support rods are provided, and multiple connecting frames are fixed between the multiple support rods. The multiple connecting frames are vertically distributed, and a chute is provided within the multiple connecting frames. An opening for the chute to pass through is provided in the middle of the connecting frames. The chute includes a bottom plate and side plates, wherein the side plates are fixed to one side of the bottom plate. Both the bottom plate and the side plates are spirally distributed. Triangular support columns for fixing the chute are connected to the inner sides of the multiple support rods. The chute is composed of multiple spiral groove segments spliced ​​together, and rubber segments are fixedly connected between the multiple spiral groove segments.

[0007] Preferably, the rubber segment has a hollow area, and a spring is provided in the hollow area. The upper end of the spring is fixedly connected to the inner wall of the upper end of the hollow area, and the lower end of the spring is fixedly connected to the inner wall of the lower end of the hollow area.

[0008] Preferably, the hollow area is further provided with a magnetic suction plate, and multiple magnetic suction plates are provided. The multiple magnetic suction plates are evenly distributed on the inner walls of the upper and lower ends of the hollow area, and the corresponding upper and lower magnetic suction plates repel each other and move away from each other.

[0009] The top of the triangular support column is fixed with a support plate, and the top of the support plate is fixed to the bottom of the base plate.

[0010] Multiple triangular support columns are distributed along the spiral trajectory of the chute.

[0011] This invention also discloses a non-standard chute design method for uniform spiral motion of bulk materials, comprising the following steps: Step 1: The motion equation of the bulk material on a three-dimensional curved surface is programmed and converted into an Excel calculation program. The motion equation of the bulk material on the chute can be expressed by the following formula: ; In the formula, The external helix angle of the chute. The external helix angle of the chute The combined angle of the bottom plate and the inclined angle φ is called the chute combined angle, which is only related to the bottom plate and the inclined angle φ. It is related to the value of φ. The angle between the direction of the chute's composite angle and the tangent direction of the chute's external helix angle is only related to... It is related to the value of φ. f Let be the coefficient of dynamic friction between the bulk material and the surface of the chute. R The outer helix radius of the chute. v The velocity of the bulk material. Let g be the acceleration of the bulk material and g be the acceleration due to gravity. To calculate the velocity of the bulk material, the angle θ through which the chute rotates in the projection direction is also needed. The value of θ and the outer helix angle of the spiral chute are then used to determine the velocity. The length s of the chute's movement path can be calculated; s=θ· R / cos ; Dividing the chute's movement path into 500 equal straight segments, the inlet and outlet velocities of the bulk material in each straight segment can be calculated. The velocity calculation formula is as follows: v t 2 -v0 2 =2 ·ds; Where vt is the outlet velocity of the bulk material in each straight segment, ds is the length of the straight segment, and vo is the inlet velocity of the bulk material in each straight segment, which is known. The second step is to input the known conditions into the calculation program. These conditions include the type of chute section, the surface parameters of the chute, the initial velocity of the bulk material, and v. o The data of the first step, ƒ, is used to calculate the speed of the bulk material. The third step is to use Excel functions and VBA programming to input the design parameters of the chute, so as to accurately calculate the coordinate data set of the graphic to be drawn. Finally, the data is converted into drawing commands recognized by AutoCAD, and points are batch plotted in AutoCAD to quickly draw the chute processing drawing.

[0012] Preferably, the chute sections are divided into straight sections and spiral sections, and multiple spiral sections are provided.

[0013] Preferably, the known conditions also include the particle size of the bulk material, the maximum conveying capacity, and the dynamic friction angle.

[0014] Preferably, the velocity of the bulk material includes the velocity of the straight section and the velocity of the spiral section.

[0015] The technical effects and advantages of this invention are as follows: 1. When bulk materials slide along the chute, they will press against the spiral groove, thereby compressing the corresponding rubber section, which has a buffering and stress-relieving effect, reducing the impact force generated by the bulk materials in an instant, and making it less likely for the bulk materials to generate dust.

[0016] 2. The spring increases the buffering capacity of the rubber section for bulk materials and makes the rubber section have the ability to return to its original position, so that the rubber section can continuously buffer and unload the bulk materials, which is especially suitable for conveying and buffering the unloading of fast coal.

[0017] 3. During the design phase, it is necessary to repeatedly adjust the chute parameters for velocity calculation. This design method, as long as the parameters are input correctly, can complete the calculation instantly, effectively avoiding the drawbacks of the complexity, tediousness, and high error rate of manually calculating calculus equations.

[0018] 4. This method can automate the basic tasks of manually drawing the three views of the chute, flattening the three-dimensional curved surface, drawing the chute flange, and reinforcing ribs, etc., and complete most of the drawing work for a chute section in a few seconds. According to the manual point-plotting drawing method, designing a set of drawings for a spatial curved surface chute takes about 15 to 18 working days, while using the parametric design method, it can be completed in less than 3 working days, increasing work efficiency by more than 5 times. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the non-standard chute used for uniform spiral motion of bulk materials according to the present invention.

[0020] Figure 2 This is a schematic diagram of the chute structure of the present invention.

[0021] Figure 3 This is a schematic diagram of the rubber segment structure of the present invention.

[0022] Figure 4 This is a schematic diagram of the steps and structure of the non-standard chute design method for uniform spiral motion of bulk materials according to the present invention.

[0023] Figure 5 This is a schematic diagram illustrating the process of drawing a top view of the spiral chute and determining the coordinates of the division points according to the present invention.

[0024] Figure 6 This is a schematic diagram of the process for determining the shape of the inner and outer spiral development lines of the spiral chute according to the present invention.

[0025] Figure 7 This is a structural schematic diagram illustrating the process of drawing the main view of the inner and outer spiral lines of the spiral chute of the present invention.

[0026] Figure 8 This is a structural schematic diagram illustrating the process of drawing the left view of the spiral chute of the present invention.

[0027] In the diagram: 1. Support rod; 2. Connecting frame; 3. Triangular support column; 4. Support plate; 5. Base plate; 6. Side plate; 7. Chute; 13. Rubber section; 14. Hollow area; 15. Magnetic suction plate; 16. Spring. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] This invention provides, for example Figures 1-8 The non-standard chute shown is for uniform spiral motion of bulk materials. It includes multiple support rods 1, and multiple connecting frames 2 are fixed between the multiple support rods 1. The multiple connecting frames 2 are vertically distributed, and a chute 7 is set in the multiple connecting frames 2. The middle of the connecting frame 2 is opened for the passage of the chute 7. The chute 7 includes a bottom plate 5 and side plates 6. The side plates 6 are fixed to one side of the bottom plate 5. Both the bottom plate 5 and the side plates 6 are spirally distributed. The inner side of each of the multiple support rods 1 is connected to a triangular support column 3 for fixing the chute 7. The chute 7 is composed of multiple spiral grooves spliced ​​together. Rubber segments 13 are fixedly connected between the multiple spiral grooves. When the bulk material slides along the chute 7, it will press the spiral grooves, thereby compressing the corresponding rubber segments 13, which has a buffering and stress-relieving effect, reducing the impact force generated by the bulk material in an instant, and making it less likely for the bulk material to generate dust.

[0030] Furthermore, a hollow area 14 is provided in the rubber section 13, and a spring 16 is provided in the hollow area 14. The upper end of the spring 16 is fixedly connected to the inner wall of the upper end of the hollow area 14, and the lower end of the spring 16 is fixedly connected to the inner wall of the lower end of the hollow area 14. The spring 16 increases the buffering capacity of the rubber section 13 for bulk materials and makes the rubber section 13 have the ability to be reset, so that the rubber section 13 can continuously buffer and unload bulk materials, which is particularly suitable for conveying and buffering fast coal.

[0031] Furthermore, a magnetic suction plate 15 is also provided in the hollow area 14. Multiple magnetic suction plates 15 are provided and are evenly distributed on the inner walls of the upper and lower ends of the hollow area 14. The corresponding magnetic suction plates 15 repel each other and move away from each other. After the spring 16 is used for a long time, it is prone to rust and damage. Therefore, in order to ensure that the chute 7 can be used for a long time, a magnetic suction plate 15 is also provided in the hollow area 14 in this invention. When the rubber segment 13 is compressed, the interaction between the corresponding magnetic suction plates 15 can make the rubber segment 13 return to its original position.

[0032] The top of the triangular support column 3 is fixed with a support plate 4, and the top of the support plate 4 is fixed to the bottom of the base plate 5.

[0033] Multiple triangular support columns 3 are distributed on the spiral trajectory of the chute 7. Coal can be input from the top of the chute 7 and eventually descend along the trajectory of the chute 7 by its own gravity.

[0034] This invention also discloses a non-standard chute design method for uniform spiral motion of bulk materials, comprising the following steps: S1. The motion equations of bulk materials on a three-dimensional curved surface are programmed into an Excel calculation program. The motion equations of bulk materials on a chute can be expressed by the following formula: ; In the formula, The external helix angle of the chute. The external helix angle of the chute The combined angle of the bottom plate and the inclined angle φ is called the chute combined angle, which is only related to the bottom plate and the inclined angle φ. It is related to the value of φ. The angle between the direction of the chute's composite angle and the tangent direction of the chute's external helix angle is only related to... It is related to the value of φ. f Let be the coefficient of dynamic friction between the bulk material and the surface of the chute. R The outer helix radius of the chute. v The velocity of the bulk material. Let g be the acceleration of the bulk material and g be the acceleration due to gravity. To calculate the velocity of the bulk material, the angle θ through which the chute rotates in the projection direction is also needed. The value of θ and the outer helix angle of the spiral chute are then used to determine the velocity. The length of the chute's movement path is calculated. s=θ·R / cos ; Dividing the chute's movement path into 500 equal straight segments, the inlet and outlet velocities of the bulk material in each straight segment can be calculated. The velocity calculation formula is as follows: v t 2 -v0 2 =2a·ds; ; where v t Let v be the outlet velocity of the bulk material in each straight segment, ds be the length of the straight segment, and v be the outlet velocity. o Let be the inlet velocity of the bulk material in each straight segment, which is known; S2. Input the known conditions into the calculation program. The known conditions include the type of chute section, the surface parameters of the chute, the initial velocity of the bulk material, and v. oUsing the data of ƒ, a calculation program is used to determine the velocity of the bulk material. Material velocity is a crucial parameter for evaluating the design level and breakage prevention effect of a chute. During the design phase, chute parameters need to be repeatedly adjusted for velocity calculations. This design method, however, can complete the calculation instantly as long as the parameters are input correctly, effectively avoiding the complexity, tediousness, and high error rate of manual calculation of calculus equations.

[0035] S3. By combining Excel's functions with VBA programming, the system can accurately calculate the coordinate data set of the graphic to be drawn by inputting the design parameters of the chute; finally, the data is converted into drawing commands recognized by AutoCAD, and points are batch-plotted in AutoCAD to quickly draw the chute machining drawing.

[0036] This method allows computers to handle the basic tasks of manually drawing the three views of the chute, flattening the three-dimensional surface, drawing the chute flanges, and reinforcing ribs. Most of the drawing work for a chute section can be completed in a few seconds. Designing a set of drawings for a spatial curved surface chute using the manual point-plotting method takes about 15 to 18 working days, while the parametric design method can be completed in less than 3 working days, increasing work efficiency by more than 5 times.

[0037] The chute sections are divided into straight sections and spiral sections, with multiple spiral sections.

[0038] The known conditions also include the particle size of the bulk material, the maximum conveying capacity, and the dynamic friction angle.

[0039] The velocity of bulk materials includes the velocity of the straight section and the velocity of the spiral section.

[0040] Example 2 Set the parameters in the material velocity calculation program interface as follows: 1. Fill in the known parameters: the name of the bulk material is lump coal, the maximum conveying capacity is 900t / h, the dynamic friction angle is 25°, the particle size is 0-150mm, the feeding speed is 0m / s, and the friction coefficient is... f =0.46308, the first segment is a straight line segment, and the second, third and fourth segments are spiral segments; 2. Determine design parameters: Based on the characteristics of bulk materials, the friction angle is set to 25°.

[0041] 3. Calculation of key point velocity and verification of throughput: In the first straight section, the feed velocity V0 = 0 m / s, and the cross-sectional area = 0.64 m². 2 The filling coefficient ψ = Q / (3600AVP) = 0.24 (where Q is the material handling capacity in tons / hour, A is the cross-sectional area of ​​the chute in square meters, v is the material velocity in m / s, and ρ is the bulk density of the material, which is usually taken as 0.9 t / m³ for coal).3 The value calculated by this formula is the ratio of the cross-sectional area of ​​the material flow to the cross-sectional area of ​​the chute. If this value is less than 0.3, there is no risk of material blockage. The filling coefficient meets the requirements.

[0042] The external helix angle of the chute in the first straight segment =35°, slope length L=0.9m.

[0043] Among them, acceleration =g sin -ƒ g cos =1.88m / s 2 ; v1=[2aL+v o 2 ] = 1.84 m / s, and based on the above calculations, v1 = 1.84 m / s.

[0044] 4. In the second spiral section, the feed velocity v1 = 1.84 m / s, and the cross-sectional area = 0.64 m². 2 The filling factor ψ = Q / (3600AVP) = 0.18, which meets the requirements.

[0045] The outer helix radius of the second helical segment R =1.5m, the external helix angle of the chute at the inlet is 1.5m. =35°, (the external helix angle is the angle between the tangent of the external helix of the chute and the horizontal plane) ψin=0°, the resultant angle of the chute=35°; The angle θ = 60° that the chute (7) rotates through in the projection direction is the outer helix angle of the chute at the outlet. =30°, ψout=12°, resultant angle=31.6°, substituting into the program, the feed inlet velocity v2=2.44m / s, the velocity at which centrifugal force and centripetal force balance is v=1.75m / s, and the velocity at which uniform motion is achieved is v. U =2.72m / s, and based on the above calculations, v2 = 2.44m / s.

[0046] 5. In the third spiral section, the feed velocity v1 = 2.44 m / s, and the cross-sectional area = 0.49 m². 2 The filling coefficient ψ = 0.17, which meets the requirements.

[0047] Radius of the third spiral segment R =2.5m, λ = 30°, ψλ = 12°, resultant angle = 31.6°, included angle θ = 60°. Given an angle of 30° and a resultant angle of 20°, the feed inlet velocity v2 = 3.31 m / s is obtained by substituting these values ​​into the program. The velocity at which centrifugal force and centripetal force balance is v = 2.92 m / s, and the velocity at which uniform motion is achieved is v.U =4.07m / s, and based on the above calculations, v2 = 3.31m / s.

[0048] 6. In the fourth spiral section, the feed velocity v1 = 3.31 m / s, and the cross-sectional area = 0.28 m². 2 The fill factor ψ = 0.24 (meets the requirements), radius R =2.5m, λ = 30°, ψλ = 12°, resultant angle = 31.6°, included angle θ = 60°. Given that the angle of inlet is 30°, ψ_out = 20°, and the resultant angle is 34.31°, substituting these values ​​into the program yields a feed inlet velocity v2 = 4.07 m / s. The velocity at which centrifugal force and centripetal force balance is v = 2.92 m / s, and the velocity at which uniform motion is achieved is v_out. U =4.07m / s, and V2 = 4.07m / s is obtained from the above calculation.

[0049] The key to drawing the three views of a spiral chute in AutoCAD is to obtain the X and Y coordinates of each point in the three views. Since the spiral chute is a three-dimensional curved surface structure, its three views are mainly composed of curves. Therefore, the curves are divided into 10 parts, and the points of each part are connected one by one for drawing.

[0050] In the three-view diagram, the X-coordinate is mainly determined by the top view of the spiral chute, and the Y-coordinate is mainly determined by the spiral development diagram of the spiral chute. Therefore, before obtaining the X and Y coordinates, it is necessary to first draw the top view and the inner and outer spiral development diagrams of the spiral chute. The top view of the spiral chute determines the radius of the outer spiral. R The figure can be drawn by using the inner spiral radius r and the spiral projection angle θ. Then, divide the inner and outer spirals into 10 equal parts, establish a base point (0,0), and calculate the X coordinate of each division point analytically. (e.g.) Figure 5 (As shown) The shape of the outer spiral development curve is determined by the projected arc length of the outer spiral of the spiral chute and the outer spiral angle. The shape of the inner spiral development curve is based on the shape of the outer spiral development curve and then determined by the projected arc length of the inner spiral of the spiral chute. (e.g.) Figure 6 (As shown) The elevation difference between the starting and ending points of the inner spiral development line in the diagram is usually designed to be the same as the elevation difference of the outer spiral development line, both being θ. R / cos Due to the presence of the inclined angle φ of the spiral chute bottom plate, Y 1外 The value is usually greater than Y 1内 Y 1外 -Y 1内 =( R -r)·tanφ. Connecting all the obtained coordinates at this point yields the main view of the inner and outer helical lines of the spiral chute. (e.g.) Figure 7 (As shown) After drawing the inner and outer spiral lines, the shape of the outer plate of the spiral chute can be obtained by directly copying and translating the drawn outer spiral line. The translation distance is determined according to the design parameters input into the program. After the three curves are drawn, the starting and ending points of the three curves are connected by straight lines to obtain the complete main view of the spiral chute.

[0051] The same principle applies to drawing the side view of a spiral chute. If drawing the left view, rotate the top view of the spiral chute counter-clockwise by 90° and recalculate the X coordinates of the equally spaced points of the inner and outer spirals. The Y coordinates of the developed lines of the inner and outer spirals remain unchanged. (e.g.) Figure 8 (As shown).

Claims

1. A non-standard chute design method for uniform spiral motion of bulk materials, characterized in that, Includes the following steps: S1. The motion equation of the bulk material on the three-dimensional curved surface is programmed into an Excel calculation program. The motion equation of the bulk material on the chute (7) is expressed by the following formula: ； In the formula, The external helix angle of the chute. The external helix angle of the chute The combined angle of the bottom plate and the inclined angle φ is called the chute combined angle, which is only related to the bottom plate and the inclined angle φ. It is related to the value of φ. The angle between the direction of the chute's composite angle and the tangent direction of the chute's external helix angle is only related to... It is related to the value of φ. f Let be the coefficient of dynamic friction of the bulk material relative to the surface of the chute (7). R The outer helix radius of the chute (7) is... v The velocity of the bulk material. Let g be the acceleration of the bulk material and g be the acceleration due to gravity. To calculate the velocity of the bulk material, the angle θ through which the chute (7) rotates in the projection direction is also needed. The value of θ and the external helix angle of the chute are used to calculate the velocity of the bulk material. The motion path length s of the chute (7) is calculated; s=θ· R / cos ; The movement path of the chute (7) is divided into 500 straight segments. The inlet and outlet velocities of the bulk material in each straight segment are calculated. The velocity calculation formula is as follows: in t 2 -v0 2 =2 ·ds; ； Among them, v t Let v be the outlet velocity of the bulk material in each straight segment, ds be the length of the straight segment, and v be the outlet velocity. o Let be the inlet velocity of the bulk material in each straight segment, which is known; S2. Input the known conditions into the calculation program. The known conditions include the type of chute section, the surface parameters of the chute, the initial velocity of the bulk material, and v. o Using the data of ƒ, the velocity of the bulk material is obtained through calculation formulas; S3. By combining Excel's functions with VBA programming, the design parameters of the chute can be input to accurately calculate the coordinate data set of the graphic to be drawn. Finally, the coordinate data set is converted into drawing commands recognized by AutoCAD, and points are batch-plotted in AutoCAD to quickly draw the chute machining drawing.

2. The non-standard chute design method for uniform spiral motion of bulk materials according to claim 1, characterized in that: The chute sections are divided into straight sections and spiral sections, and multiple spiral sections are provided.

3. The non-standard chute design method for uniform spiral motion of bulk materials according to claim 1, characterized in that: The known conditions also include the particle size of the bulk material, the maximum transport capacity, and the dynamic friction angle.

4. The non-standard chute design method for uniform spiral motion of bulk materials according to claim 2, characterized in that: The speed of the bulk material includes the speed of the straight section and the speed of the spiral section.

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