Method for reducing failure rate of roller screen

Abstract

The embodiment of the invention provides a method for reducing the failure rate of a roller screen, and relates to the technical field of roller screens. The method for reducing the failure rate of the roller screens comprises the steps that the included angle formed when green pellets are located between two roller screens in the same stage is obtained; obtaining the relative displacement of the green pellets from the previous-stage roller screen to the next-stage roller screen; and calculating the linear speed of the two roller screens in the same level according to the included angle of the green pellets between the two roller screens and the relative displacement of the green pellets from the previous level of roller screen to the next level of roller screen. And the two roller screens in the same stage respectively run according to the calculated linear speeds, so that the green pellets are continuously in an unstable state, the balance between the green pellets and the two roller screens in the same stage is broken, the speed of the green pellets is increased, the green pellets are separated from the position between the two roller screens in the same stage, material accumulation is reduced, and the failure rate of the roller screens is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of roller screens, and in particular to a method for reducing the failure rate of roller screens. Background Art

[0002] Currently, disc pelletizers are a type of pelletizing equipment commonly used in the metallurgical, chemical, and building materials industries. They are primarily used to produce pellets of a certain size (such as iron ore pellets and fertilizer granules) by rolling and agglomerating powdered materials. The disc pelletizers used in rotary hearth furnace pelletizing systems produce small-diameter raw pellets. During the raw pellet screening process, they accumulate on the roller screen surface, significantly increasing the motor load and even causing it to jam. This leads to frequent motor trips and stops, severely impacting production schedules and increasing the workload of on-site operators.

[0003] Therefore, the roller screen of the disc pelletizing machine in the prior art has a technical problem of a high failure rate. Summary of the Invention

[0004] The present invention provides a method for reducing the failure rate of a roller screen, which can reduce the probability of failure occurring during the operation of the roller screen and ensure the normal operation of the roller screen.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] An embodiment of the present invention provides a method for reducing the failure rate of a roller screen, comprising:

[0007] Get the angle between the two roller screens in the same level when the green balls are in the middle;

[0008] Obtain the relative displacement of the green balls when they move from the previous roller screen to the next roller screen;

[0009] The linear speeds of the two roller screens in the same level are calculated based on the angle between the two roller screens and the relative displacement of the green balls when they reach the next roller screen from the previous roller screen.

[0010] Optionally, the two roller screens in the same level are respectively a first roller screen and a second roller screen, and the step of calculating the linear speed of the two roller screens in the same level according to the angle between the green balls and the relative displacement of the green balls when they reach the next roller screen from the previous roller screen comprises:

[0011] The angle between the two roller screens and the relative displacement of the green balls when they move from the upper roller screen to the lower roller screen are substituted into the linear velocity calculation formula of the first roller screen to obtain the linear velocity of the first roller screen;

[0012] The angle between the two roller screens and the relative displacement of the green balls when they reach the next roller screen from the previous roller screen are substituted into the linear velocity calculation formula of the second roller screen to obtain the linear velocity of the second roller screen.

[0013] Optionally, the formula for calculating the linear velocity of the first roller screen is as follows:

[0014]

[0015] In the formula: b is the linear velocity of the first roller screen; μ is the relative friction factor between the first roller screen and the second roller screen; R is the radius of the first roller screen; r is the radius of the green pellet; a is the linear velocity of the green pellet; α is half of the distance between the first roller screen and the second roller screen.

[0016] Optionally, the formula for calculating the linear velocity of the second roller screen is as follows:

[0017]

[0018] In the formula: c is the linear velocity of the second roller screen; μ is the relative friction factor between the first roller screen and the second roller screen; R is the radius of the second roller screen; r is the radius of the green pellet; b is the linear velocity of the first roller screen; α is half of the distance between the first roller screen and the second roller screen.

[0019] Optionally, when two roller screens in the same stage are the first roller screen and the second roller screen respectively, the steps of obtaining the included angle θ when the green pellet is between the two roller screens in the same stage include:

[0020] Obtain the linear velocity of the green pellet, the radius of the green pellet, the radius of the roller screen, and the distance between the first roller screen and the second roller screen, and substitute the linear velocity of the green pellet, the radius of the green pellet, the radius of the roller screen, and the distance between the first roller screen and the second roller screen into the included angle calculation formula to calculate the included angle;

[0021] Wherein, the radius of the first roller screen is the same as the radius of the second roller screen.

[0022] Optionally, the formula for calculating the included angle when the green pellet is between the first roller screen and the second roller screen is as follows:

[0023]

[0024] In the formula: θ is the included angle when the green pellet is between the first roller screen and the second roller screen; R is the radius of the second roller screen; r is the radius of the green pellet; α is half of the distance between the first roller screen and the second roller screen.

[0025] Optionally, the steps of obtaining the relative displacement when the green pellet reaches the next-stage roller screen from the previous-stage roller screen include:

[0026] Calculate the relative displacement when the green pellet reaches the next-stage roller screen from the previous-stage roller screen through the relative displacement calculation formula.

[0027] Optionally, the relative displacement calculation formula is as follows:

[0028] s = (π - 2θ)R

[0029] Where: s is the relative displacement of the green balls when they reach the lower roller screen from the upper roller screen; θ is the angle between the two roller screens of the same level where the green balls are located; R is the radius of the roller screen.

[0030] Optionally, after the step of obtaining the relative displacement of the green balls when they reach the lower roller screen from the upper roller screen, the method for reducing the failure rate of the roller screen further includes:

[0031] Calculating the internal energy generated by the green balls during the movement through the work calculation formula.

[0032] Optionally, the work calculation formula is:

[0033]

[0034] Where: f is the frictional force; s is the relative displacement of the green balls when they reach the lower roller screen from the upper roller screen; b is the linear velocity of the first roller screen; a is the linear velocity of the green balls; m is the mass of the green balls.

[0035] The beneficial effects of the method for reducing the failure rate of the roller screen according to the embodiments of the present invention include, for example:

[0036] The method for reducing the failure rate of the roller screen includes obtaining the angle between the two roller screens of the same level where the green balls are located; obtaining the relative displacement of the green balls when they reach the lower roller screen from the upper roller screen; calculating the linear velocities of the two roller screens of the same level based on the angle between the two roller screens where the green balls are located and the relative displacement of the green balls when they reach the lower roller screen from the upper roller screen. During use, the linear velocities of the two roller screens of the same level can be calculated through the angle between the two roller screens of the same level where the green balls are located and the relative displacement of the green balls when they reach the lower roller screen from the upper roller screen. The two roller screens of the same level operate respectively according to the calculated linear velocities, so that the green balls are continuously in an unstable state, breaking the balance between the green balls and the two roller screens of the same level, enabling the speed of the green balls to increase and break away from between the two roller screens of the same level, thereby reducing material accumulation and further reducing the failure rate of the roller screen. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a schematic structural diagram of the green balls between the two roller screens of the same level.

[0039] Icons: 10 - green balls; 20 - first roller screen; 30 - second roller screen. Specific embodiments

[0040] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention described and illustrated herein generally may be arranged and designed in a variety of different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but is merely representative of selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0042] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0043] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship in which the product of the invention is usually placed during use. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0044] In addition, if terms such as "first", "second", etc. are used only for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0045] It should be noted that the features in the embodiments of the present invention may be combined with each other without conflict.

[0046] Currently, the disk pelletizer is a granulation device commonly used in industries such as metallurgy, chemical engineering, and building materials, mainly used to make spherical particles of a certain particle size (such as iron ore powder pelletizing, chemical fertilizer particles, etc.) by means of rolling and agglomeration. The green balls produced by the disk pelletizer used in the rotary hearth furnace pelletizing are relatively small in diameter. At the green ball screening stage, they accumulate in large quantities on the surface of the roller screen, greatly increasing the motor load and even jamming, resulting in frequent motor trips and seriously affecting the production progress. It also increases the working intensity of on-site operators.

[0047] Therefore, the roll screen of the disc pelletizer in the related art has the technical problem of relatively high failure rate.

[0048] It should be noted that during the operation of the disc pelletizer, the green balls 10 generated will sequentially pass through multiple levels of roll screens inside the disc pelletizer for layer-by-layer screening. During the screening process of the green balls 10, a large number of green balls 10 are likely to accumulate in the gaps of the roll screen. Currently, there is no relatively systematic method for dealing with the accumulation of roll screen materials. Either manual cleaning is adopted, which increases the labor intensity of on-site workers and also delays the problem-solving speed; or the distance between the roll screens is reduced, but this treatment method is not universal and cannot handle the screening of green balls 10 of smaller particles. At the same time, it will also reduce the success rate of material screening, making some green balls 10 of unqualified size unable to be screened out; or the overall rotational speed of the roll screen is increased, and the green balls 10 are quickly taken out of the roll screen by using a faster rotational speed, but this method incurs a relatively high production cost. Therefore, to solve the above technical problems, this embodiment provides a method for reducing the failure rate of the roll screen, which can effectively improve the above-mentioned technical problems, can reduce the probability of failure during the operation of the roll screen, and ensure the normal operation of the roll screen.

[0049] Please refer to Figure 1 , the method for reducing the failure rate of the roll screen provided in this embodiment includes:

[0050] S1: Obtain the included angle when the green ball 10 is between two roll screens in the same level.

[0051] Specifically, the two roll screens in the same level are respectively the first roll screen 20 and the second roll screen 30. The first roll screen 20 and the second roll screen 30 are arranged at intervals and rotate in the same direction. Obtain the linear velocity of the green ball 10, obtain the radius of the green ball 10, obtain the radius of the roll screen, obtain the distance between the first roll screen 20 and the second roll screen 30, and substitute the linear velocity of the green ball 10, the radius of the green ball 10, the radius of the roll screen, and the distance between the first roll screen 20 and the second roll screen 30 into the included angle calculation formula for calculation to obtain the included angle. Among them, the radius of the first roll screen 20 is the same as the radius of the second roll screen 30.

[0052] In this embodiment, the calculation formula for the included angle when the green ball 10 is between the first roll screen 20 and the second roll screen 30 is:

[0053]

[0054] In the formula: θ is the included angle when the green ball 10 is between the first roll screen 20 and the second roll screen 30; R is the radius of the second roll screen 30; r is the radius of the green ball 10.

[0055] S2: Obtain the relative displacement when the green ball 10 reaches the next-level roll screen from the previous-level roll screen.

[0056] Specifically, the relative displacement of the green pellets 10 when reaching the next-stage roller screen from the previous-stage roller screen is calculated through the relative displacement calculation formula.

[0057] Optionally, the relative displacement calculation formula is:

[0058] s = (π - 2θ)R

[0059] In the formula: s is the relative displacement of the green pellets 10 when reaching the next-stage roller screen from the previous-stage roller screen; θ is the included angle between the two roller screens of the green pellets 10 in the same stage; R is the radius of the roller screen.

[0060] S3: The internal energy generated by the green pellets 10 during the movement is calculated through the work calculation formula.

[0061] Optionally, the work calculation formula is:

[0062]

[0063] In the formula: f is the frictional force; s is the relative displacement of the green pellets 10 when reaching the next-stage roller screen from the previous-stage roller screen; b is the linear velocity of the first roller screen 20; a is the linear velocity of the green pellets 10; m is the mass of the green pellets 10.

[0064] S4: The linear velocities of the two roller screens in the same stage are calculated based on the included angle of the green pellets 10 between the two roller screens and the relative displacement of the green pellets 10 when reaching the next-stage roller screen from the previous-stage roller screen.

[0065] Specifically, the included angle of the green pellets 10 between the two roller screens and the relative displacement of the green pellets 10 when reaching the next-stage roller screen from the previous-stage roller screen are substituted into the linear velocity calculation formula of the first roller screen 20 to obtain the linear velocity of the first roller screen 20; the included angle of the green pellets 10 between the two roller screens and the relative displacement of the green pellets 10 when reaching the next-stage roller screen from the previous-stage roller screen are substituted into the linear velocity calculation formula of the second roller screen 30 to obtain the linear velocity of the second roller screen 30.

[0066] Among them, the linear velocity calculation formula of the first roller screen 20 is:

[0067]

[0068] In the formula: b is the linear velocity of the first roller screen 20; μ is the relative friction factor between the first roller screen 20 and the second roller screen 30; R is the radius of the first roller screen 20; r is the radius of the green pellets 10; a is the linear velocity of the green pellets 10.

[0069] The linear velocity calculation formula of the second roller screen 30 is:

[0070]

[0071] Where: c is the linear velocity of the second roller screen 30; μ is the relative friction factor between the first roller screen 20 and the second roller screen 30; R is the radius of the second roller screen 30; r is the radius of the green pellet 10; b is the linear velocity of the first roller screen 20; α is half of the distance between the first roller screen 20 and the second roller screen 30.

[0072] The inventor analyzed and found that the reason for the large accumulation of the material green pellets 10 in the roller screen gap is nothing but the formation of a relatively stable dynamic balance between the green pellets 10 and the roller screen. The material pellets coming out of the disk pelletizer tend to be spherical in shape. Take a green pellet 10 for analysis. Assume that the green pellet 10 rotates clockwise in the air at a linear velocity magnitude of a. At this time, two inverted first roller screens 20 and second roller screens 30 are placed on the left and right sides of the green pellet 10 respectively, and they rotate counterclockwise at the same linear velocity magnitude of a (Note: the diameters of the first roller screen 20 and the second roller screen 30 are about 3 times the size of the green pellet 10), and the first roller screen 20 and the second roller screen 30 are respectively close to the green pellet 10 (there is no contact between the first roller screen 20 and the second roller screen 30). Since the linear velocity magnitudes of the three are the same, the surface of the green pellet 10 is relatively stationary with the surfaces of the first roller screen 20 and the second roller screen 30, and there is no frictional force among the three to affect the motion state of the green pellet 10, so that the green pellet 10 will maintain its original state and get stuck between the first roller screen 20 and the second roller screen 30 and rotate clockwise at a linear velocity magnitude of a; without external interference, there will be no change, which is the reason why the green pellet 10 can stably stay and rotate between the first roller screen 20 and the second roller screen 30. In actual production, the motion state of the green pellet 10 is always affected by irresistible forces, resulting in kinetic energy loss and speed reduction; at this time, due to the linear velocity difference between the two roller screens and the green pellet 10, under the action of frictional force, the roller screen needs to drive the green pellet 10 to accelerate to the original state, directly increasing the motor output power and the load, resulting in the motor tripping.

[0073] If the green balls 10 and the two roller screens can maintain a dynamic balance until the arrival of the next wave of materials, due to the gap between the first roller screen 20 and the second roller screen 30, the green balls 10 will be impacted by the next wave of materials. Take the green balls 10 in the next wave of materials and the original green balls 10 for analysis. Assume that the two green balls 10 have the same motion state. When the green balls 10 in the next wave of materials approach the original green balls 10, due to the opposite directions of the linear velocities of the contact surfaces of the two green balls 10, the two balls will be affected by friction, resulting in a decrease in speed, which in turn leads to the appearance of friction between the balls and the roller screens, driving the green balls 10 to accelerate continuously; this process repeats, increasing the motor load. And the original green balls 10 will be squeezed by the green balls 10 in the next wave of materials, thus receiving an obliquely downward force. In actual production operations, the green balls 10 contain a certain amount of moisture and will deform when subjected to a large pressure, getting stuck between the gaps of the two roller screens, resulting in the motor tripping. Through the above cause analysis, reducing the accumulation of materials and disrupting the dynamic balance between the green balls 10 and the roller screens can directly solve the above problems fundamentally. Since the dynamic balance between the green balls 10 and the two roller screens is due to the relative static state between the contact surfaces of the three, introducing a certain amount of speed difference to cause friction between the contact surfaces can directly disrupt the relative static state between the contact surfaces, making the green balls 10 in an unstable state; under the action of friction, the speed of the green balls 10 increases, and they break away from the gaps between the two roller screens, minimizing the accumulation of materials to the greatest extent, thereby reducing the failure rate of the roller screens.

[0074] In this embodiment, both the first roller screen 20 and the second roller screen 30 rotate clockwise, and the green balls 10 rotate counterclockwise.

[0075] Through the method for reducing the failure rate of the roller screen provided in this embodiment, the linear velocity b of the first roller screen 20 and the linear velocity c of the second roller screen 30 can be calculated. That is to say, when the linear velocity b of the first roller screen 20 and the linear velocity c of the second roller screen 30 in the same stage reach the calculated values, the green balls 10 can be in an "accelerated" state, avoiding the green balls 10 getting stuck in the gap between the first roller screen 20 and the second roller screen 30, thus avoiding the accumulation of materials and reducing the failure rate of the roller screen.

[0076] In summary, the embodiment of the present invention provides a method for reducing the failure rate of a roller screen. The method for reducing the failure rate of the roller screen includes obtaining the included angle when the green pellets 10 are between two roller screens in the same level; obtaining the relative displacement when the green pellets 10 reach the next-level roller screen from the previous-level roller screen; calculating the linear speeds of the two roller screens in the same level based on the included angle when the green pellets 10 are between the two roller screens and the relative displacement when the green pellets 10 reach the next-level roller screen from the previous-level roller screen. When in use, the linear speeds of the two roller screens in the same level can be calculated through the included angle between the two roller screens in the same level for the green pellets 10 and the relative displacement when the green pellets 10 reach the next-level roller screen from the previous-level roller screen. The two roller screens in the same level operate respectively according to the calculated linear speeds, so that the green pellets 10 are continuously in an unstable state, breaking the balance between the green pellets 10 and the two roller screens in the same level, enabling the speed of the green pellets 10 to increase and break away from between the two roller screens in the same level, thereby reducing material accumulation and further reducing the failure rate of the roller screen.

[0077] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for reducing the failure rate of a roller screen, characterized in that Including: Obtaining the included angle when the green pellets (10) are between two roller screens at the same level; Obtaining the relative displacement of the green pellets (10) when reaching the next-level roller screen from the previous-level roller screen; Calculating the linear speeds of two roller screens at the same level according to the included angle when the green pellets (10) are between the two roller screens and the relative displacement of the green pellets (10) when reaching the next-level roller screen from the previous-level roller screen.

2. The method for reducing the failure rate of the roller screen according to claim 1, wherein The two roller screens at the same level are the first roller screen (20) and the second roller screen (30) respectively. The step of calculating the linear speeds of the two roller screens at the same level according to the included angle when the green pellets (10) are between the two roller screens and the relative displacement of the green pellets (10) when reaching the next-level roller screen from the previous-level roller screen includes: Substituting the included angle when the green pellets (10) are between the two roller screens and the relative displacement of the green pellets (10) when reaching the next-level roller screen from the previous-level roller screen into the linear speed calculation formula of the first roller screen (20) to obtain the linear speed of the first roller screen (20); Substituting the included angle when the green pellets (10) are between the two roller screens and the relative displacement of the green pellets (10) when reaching the next-level roller screen from the previous-level roller screen into the linear speed calculation formula of the second roller screen (30) to obtain the linear speed of the second roller screen (30).

3. The method for reducing the failure rate of the roller screen according to claim 2, characterized in that, The linear speed calculation formula of the first roller screen (20) is: Where: b is the linear speed of the first roller screen (20); μ is the relative friction factor between the first roller screen (20) and the second roller screen (30); R is the radius of the first roller screen (20); r is the radius of the green pellets (10); a is the linear speed of the green pellets (10); α is half of the distance between the first roller screen (20) and the second roller screen (30).

4. The method for reducing the failure rate of the roller screen according to claim 2, wherein The linear speed calculation formula of the second roller screen (30) is: Where: c is the linear speed of the second roller screen (30); μ is the relative friction factor between the first roller screen (20) and the second roller screen (30); R is the radius of the second roller screen (30); r is the radius of the green pellets (10); b is the linear speed of the first roller screen (20); α is half of the distance between the first roller screen (20) and the second roller screen (30).

5. The method for reducing the failure rate of the roller screen according to claim 1, characterized in that, The two roller screens at the same level are the first roller screen (20) and the second roller screen (30) respectively. The step of obtaining the included angle θ when the green pellets (10) are between the two roller screens at the same level includes: Obtaining the linear speed of the green pellets (10), obtaining the radius of the green pellets (10), obtaining the radius of the roller screen, obtaining the distance between the first roller screen (20) and the second roller screen (30), and substituting the linear speed of the green pellets (10), the radius of the green pellets (10), the radius of the roller screen, and the distance between the first roller screen (20) and the second roller screen (30) into the included angle calculation formula for calculation to obtain the included angle; Wherein, the radius of the first roller screen (20) is the same as the radius of the second roller screen (30).

6. The method for reducing the failure rate of the roller screen according to claim 5, characterized in that, The included angle calculation formula when the green pellets (10) are between the first roller screen (20) and the second roller screen (30) is: In the formula: θ is the included angle between the green pellets (10) located between the first roller screen (20) and the second roller screen (30); R is the radius of the second roller screen (30); r is the radius of the green pellets (10); α is half of the distance between the first roller screen (20) and the second roller screen (30).

7. The method for reducing the failure rate of the roller screen according to claim 2, wherein, The step of obtaining the relative displacement of the green pellets (10) when moving from the upper-level roller screen to the lower-level roller screen includes: Calculating the relative displacement of the green pellets (10) when moving from the upper-level roller screen to the lower-level roller screen through the relative displacement calculation formula.

8. The method for reducing the failure rate of the roller screen according to claim 7, characterized in that, The relative displacement calculation formula is: s = (π - 2θ)R In the formula: s is the relative displacement of the green pellets (10) when moving from the upper-level roller screen to the lower-level roller screen; θ is the included angle between the green pellets (10) located between two roller screens at the same level; R is the radius of the roller screen.

9. The method for reducing the failure rate of a roller screen according to claim 7, characterized in that, After the step of obtaining the relative displacement of the green pellets (10) when moving from the upper-level roller screen to the lower-level roller screen, the method for reducing the failure rate of the roller screen further includes: Calculating the internal energy generated by the green pellets (10) during the movement through the work calculation formula.

10. The method for reducing the failure rate of the roller screen according to claim 9, wherein The work calculation formula is: In the formula: f is the frictional force; s is the relative displacement of the green pellets (10) when moving from the upper-level roller screen to the lower-level roller screen; b is the linear velocity of the first roller screen (20); a is the linear velocity of the green pellets (10); m is the mass of the green pellets (10).

Images