A bar screen frame with multi-stage guide angle

Abstract

The utility model discloses a kind of bar screen frame with multistage flow guide angle, it is related to material screening equipment technical field, including upper fixed ring, lower fixed ring and the even arrangement of several rods along circumference, the both ends of the rod are fixed on upper and lower fixed ring respectively, and form screen gap between adjacent rods;Its characterized in that, the cross section of the rod is polygon, at least including for towards pulp flow's pulp face and back to pulp flow's back pulp face, the pulp face forms first acute angle with screen drum radial reference line, the back pulp face forms second acute angle with the radial reference line, and the first acute angle is greater than the second acute angle, the range of the first acute angle is 10 °-35 °, the range of the second acute angle is 5 °-25 °;The utility model is by designing pulp face 16 °, back pulp face 10 ° specific angle combination, narrow inlet screen gap and micro vortex generation structure, optimizes pulp flow guide, reduces turbulence and resistance, improves good pulp pass rate.

Description

Technical Field

[0001] This utility model relates to the technical field of material screening equipment, specifically to a bar screen frame with multi-stage flow guiding angles. Background Technology

[0002] Bar screen drums are key components in modern screening equipment, and their performance directly affects screening efficiency, service life, and operational stability. Existing bar screen drums typically consist of multiple bars fixed to upper and lower fixing rings by welding or simple assembly. To improve performance, various methods have been explored for the cross-sectional shape and arrangement of the bars, such as using wedge-shaped bars to form screen gaps or arranging the bars at a certain angle to guide the slurry flow.

[0003] However, in practical applications, the conventional single-angle bars of the existing bar screen drum cannot simultaneously meet the multiple requirements of guiding flow, screening and slag discharge, which easily leads to turbulence and fiber blockage at the inlet of the screen gap; secondly, the structural stability is insufficient. Under long-term impact of slurry, the welded bars are prone to cracking at the weld points, and the thermal stress and deformation generated during the welding process will change the precise gap between the bars, affecting the screening accuracy. Utility Model Content

[0004] The purpose of this invention is to provide a bar screen frame with multi-stage flow guiding angles to solve the problems in the prior art where conventional single-angle bars cannot simultaneously meet the multiple requirements of flow guiding, screening and slag discharge, resulting in poor slurry flow guidance.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a bar screen frame with multi-level flow guiding angles, comprising an upper fixed ring, a lower fixed ring, and a plurality of bars evenly arranged circumferentially, wherein the two ends of the bars are respectively fixed to the upper and lower fixed rings, and a screen gap is formed between adjacent bars; characterized in that the cross-section of the bars is polygonal, including at least a slurry-facing surface for facing the slurry flow and a slurry-returning surface for facing away from the slurry flow, wherein the slurry-facing surface forms a first acute angle with the radial reference line of the screen drum, and the slurry-returning surface forms a second acute angle with the radial reference line, and the first acute angle is greater than the second acute angle, wherein the range of the first acute angle is 10°-35°, and the range of the second acute angle is 5°-25°.

[0006] Furthermore, the first acute angle is 16° and the second acute angle is 10°.

[0007] Furthermore, the upper and lower fixing rings have annular protrusions on their opposite surfaces, and the end of the bar has an annular groove that matches the annular protrusions. The annular protrusions and the annular grooves form a mechanical locking structure through an interference fit.

[0008] Furthermore, the outer wall of the bar is provided with limiting rings that are spaced apart vertically to fix the bar, and the bar's slurry-facing surface and back surface are provided with outwardly protruding limiting portions.

[0009] Furthermore, the limiting ring is provided with a ring-shaped docking groove, and the limiting part on the bar is inserted into the docking groove.

[0010] Furthermore, in a cross section perpendicular to the axis of the bar, the fan-shaped profile of the bar is formed by at least three sides connected in sequence, wherein the first side is parallel to the Y-axis, the second side forms a 16° angle with the Y-axis, and the third side forms a 14° angle with the Y-axis.

[0011] Furthermore, the slurry-facing and slurry-returning surfaces of two adjacent bars along their own length direction are divided into at least three functional sections: an inlet section, a screening section, and an outlet section, and the angle of the slurry-facing surface of the inlet section is greater than the angle of the screening section, forming a narrow inlet gradually widening channel structure.

[0012] Furthermore, each of the bars has several micro-grooves extending along the bar axis on its slurry-facing surface.

[0013] Furthermore, the mechanical locking structure is an interference fit formed by heating and expanding the upper and lower fixed rings, assembling them with a bar, and then cooling and shrinking them.

[0014] Furthermore, the inner top surface of the bar is parallel to the tangential direction of the screen drum.

[0015] Compared with existing technologies, the present invention provides a bar screen frame with multi-stage flow guiding angles. By designing the bar cross-section so that the angle of the pulp-facing side is greater than that of the pulp-returning side, this structure forms an asymmetrical, gradually expanding flow channel at the inlet of the screen opening. When the pulp impacts the screen drum, the larger angle of the pulp-facing side can more effectively transform the vertically impacting pulp flow into a smooth shear flow and guide it to the screen opening; while the smaller angle of the pulp-returning side provides a smoother outlet for the good pulp passing through the screen opening. This synergistic effect of "guiding at the front and stabilizing at the back" improves the fluid dynamic environment at the inlet of the screen opening and effectively avoids fiber entanglement, bridging and clogging at the inlet.

[0016] Moreover, the optimized slurry flow guidance mentioned above allows more slurry to be effectively "transported" to the screen openings for screening, rather than randomly impacting the bars or sliding down the screen drum surface. This not only increases the amount of good slurry passing through the screen openings per unit time, but also reduces the "lingering" time of good slurry near the screen openings due to the smoother flow, thereby improving the overall screening efficiency and processing capacity of the screen drum. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0018] Figure 1 A schematic diagram of the overall structure of the bar screen frame with multi-stage flow guiding angle provided for an embodiment of this utility model;

[0019] Figure 2 This is a schematic diagram of the structure between two adjacent bars provided in an embodiment of the present utility model;

[0020] Figure 3 A cross-sectional view of the bar and limiting ring provided in an embodiment of this utility model;

[0021] Figure 4 This is a schematic diagram of the upper fixing ring and the annular protrusion component provided in an embodiment of the present utility model;

[0022] Figure 5 A schematic diagram of the annular groove and limiting ring structure on a single bar provided in an embodiment of this utility model.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Upper fixing ring; 2. Lower fixing ring; 3. Bar; 4. Screen gap; 5. Slurry-facing surface; 6. Slurry-returning surface; 7. Annular protrusion; 8. Annular groove; 9. Limiting ring; 10. Limiting part; 11. Connecting groove; 12. Inlet section; 13. Screening section; 14. Outlet section; 15. Micro-groove. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0026] As attached Figure 1 To be continued Figure 5 As shown:

[0027] Example:

[0028] This utility model provides a bar screen frame with multi-level flow guiding angles, including an upper fixing ring 1, a lower fixing ring 2, and a plurality of bars 3 evenly arranged circumferentially. The two ends of the bars 3 are respectively fixed to the upper and lower fixing rings 2, and a screen gap 4 is formed between adjacent bars 3. The bar 3 has a polygonal cross-section and includes at least a slurry-facing surface 5 facing the slurry flow and a slurry-returning surface 6 facing away from the slurry flow. The slurry-facing surface 5 forms a first acute angle with the radial reference line of the screen drum, and the slurry-returning surface 6 forms a second acute angle with the radial reference line. The first acute angle is greater than the second acute angle. The range of the first acute angle is 10°-35°, and the range of the second acute angle is 5°-25°.

[0029] It should be noted that by designing the cross-section of bar 3 such that the angle of the pulp-facing surface 5 is greater than that of the pulp-returning surface 6, this structure forms an asymmetrical, gradually expanding flow channel at the inlet of screen slot 4. When the pulp impacts the screen drum, the larger angle of the pulp-facing surface 5 can more effectively transform the vertically impacting pulp flow into a smooth shear flow and guide it to screen slot 4; while the smaller angle of the pulp-returning surface 6 provides a smoother outlet for the good pulp passing through screen slot 4. This synergistic effect of "guiding in front and stabilizing behind" improves the fluid dynamic environment at the inlet of screen slot 4 and effectively avoids fiber entanglement, bridging and clogging at the inlet.

[0030] Moreover, the optimized slurry flow guidance mentioned above allows more slurry to be effectively "transported" to the screen slot 4 for screening, rather than randomly impacting the bars 3 or sliding down the screen drum surface. This not only increases the amount of good slurry passing through the screen slot 4 per unit time, but also reduces the "lingering" time of good slurry near the screen slot 4 due to the smoother flow, thereby improving the overall screening efficiency and processing capacity of the screen drum.

[0031] In this embodiment: the first acute angle is 16°, and the second acute angle is 10°.

[0032] It should be noted that this specific angle combination is the optimal solution obtained through extensive fluid dynamics simulations and experimental verification. The 16° angle of the slurry-facing side (angle 5) ensures sufficient flow guidance while avoiding slurry splashing caused by excessive angle; the 10° angle of the slurry-returning side (angle 6) provides good flow field stability and ensures that fibers passing through the screen slot (angle 4) can detach smoothly, preventing secondary entanglement. This precise ratio allows the screen drum to maintain stable screening efficiency when processing slurries of different concentrations.

[0033] In this embodiment: the upper fixing ring 1 and the lower fixing ring 2 are provided with annular protrusions 7 on their opposite surfaces, and the end of the bar 3 is provided with annular grooves 8 that are adapted to the annular protrusions 7. The annular protrusions 7 and the annular grooves 8 form a mechanical locking structure through an interference fit.

[0034] It should be noted that this mechanical locking structure replaces the traditional welding fixing method. The cooperation between the annular protrusion 7 and the groove forms a three-dimensional constraint, which can effectively limit the displacement of the bar 3 in the radial, axial and circumferential directions. This design eliminates the material performance degradation problem caused by the heat-affected zone of welding, avoids uneven screen gaps 4 caused by welding deformation, and provides convenience for subsequent maintenance and replacement of individual bars 3.

[0035] In this embodiment: the outer wall of the bar 3 is provided with limiting rings 9 spaced vertically to fix the bar 3, and the bar 3 has outwardly protruding limiting parts 10 on the slurry-facing surface 5 and the slurry-backing surface 6.

[0036] It should be noted that the limiting ring 9 and the limiting part 10 on the bar 3 together constitute a distributed support system, which can effectively suppress the vibration and bending deformation of the bar 3 under the impact of slurry. The limiting rings 9 distributed at intervals on the upper and lower sides are equivalent to setting multiple reinforcing support points in the length direction of the bar 3, which significantly improves the overall rigidity and stability of the screen drum. Especially when dealing with large flow and high concentration slurry, it can maintain the long-term stability of the geometric dimensions of the screen gap 4.

[0037] In this embodiment: the limiting ring 9 is provided with a ring-shaped docking groove 11, and the limiting part 10 on the bar 3 is inserted into the docking groove 11.

[0038] It should be noted that the insertion and connection between the docking groove 11 and the limiting part 10 enables modular installation of the bars 3. During installation, the limiting part 10 of the bar 3 only needs to be slid into the docking groove 11 axially to achieve precise positioning. This structure ensures the precise arrangement of a large number of bars 3 in the circumferential direction, guaranteeing the consistency of the width of all screen gaps 4. At the same time, the insertion structure facilitates disassembly and maintenance; when a single bar 3 is damaged, it can be directly replaced without affecting the positional accuracy of adjacent bars 3.

[0039] In this embodiment: on a cross section perpendicular to the axis of bar 3, the fan-shaped profile of bar 3 is formed by connecting at least three sides in sequence, wherein the first side is parallel to the Y-axis, the second side forms a 16° angle with the Y-axis, and the third side forms a 14° angle with the Y-axis.

[0040] It should be noted that this multi-segment fan-shaped profile design gives the screen gap 4 formed between adjacent bars 3 an optimized geometry. The first side ensures precise dimensional control of the inlet size of the screen gap 4; the second side with a 16° included angle provides the main guiding effect; and the third side with a 14° included angle plays a role in transitioning and stabilizing the flow field. This composite angle design, compared to a single angle, can better adapt to the flow characteristics of the slurry within the screen gap 4, reduce dead zones, and improve screening efficiency.

[0041] In this embodiment, the slurry-facing surface 5 and the slurry-returning surface 6 of two adjacent bars 3 along their own length direction are divided into at least three functional sections: inlet section 12, screening section 13 and outlet section 14, and the angle of the slurry-facing surface 5 of the inlet section 12 is greater than the angle of the screening section 13, forming a narrow inlet gradually widening channel structure.

[0042] It should be noted that this "functional gradient" design along the length of bar 3 is a precise optimization for the fluid state and screening task of the pulp at different positions within the screen drum. Specifically, the pulp-facing surface 5 of the inlet section 12 adopts a larger angle (e.g., 20° to 25°). Its core function is to use a steeper slope to buffer and initially distribute the high-speed impacting material, quickly guiding the pulp flow to the screen slot 4. The strong shear force generated by the large angle can effectively break up any fiber clumps that may form, preventing inlet blockage. At this time, the screen slot 4 exhibits a "narrow inlet" characteristic, strictly intercepting excessively large impurities. The pulp-facing surface 5 of the screening section 13 adopts an optimized main screening angle (e.g., 16°). This angle can provide stable pressure and flow field for fibers to pass through the screen slot 4 while ensuring sufficient flow guidance capacity. The screen slot 4 expands into a "gradually widening channel" in this section, allowing the accepted good pulp to pass through smoothly and reducing frictional resistance. The angle of the slurry-facing surface 5 of the outlet section 14 is further reduced (e.g., from 8° to 12°) to accommodate the increased slurry concentration and decreased fluidity at this time. Its main task is to allow the remaining good slurry to pass through smoothly and to guide the separated heavy impurities (such as sand particles) smoothly to the slag discharge port to prevent them from accumulating at the end of the screen drum.

[0043] In this embodiment, each of the bars 3 has several micro-grooves 15 on its slurry-facing surface 5, extending along the axis of the bar 3.

[0044] It should be noted that these micro-grooves 15 have a depth of 0.1–0.3 mm and a width of 0.2–0.5 mm. By forming a specific textured structure on the surface of the rods 3, they can generate tiny eddies in the slurry boundary layer. These micro-eddies have a dual function: on the one hand, they can disrupt the adhesion of fibers to the surface of the rods 3, achieving a self-cleaning effect; on the other hand, they can reduce fluid friction resistance and increase the speed at which the slurry passes through the screen openings 4, thereby increasing the processing capacity by approximately 15%–20%.

[0045] In this embodiment, the mechanical locking structure is formed by heating and expanding the upper fixing ring 1 and the lower fixing ring 2, assembling the bar 3, and then cooling and shrinking them to form an interference fit.

[0046] It should be noted that the key to the hot-fitting process lies in controlling the heating temperature and the interference fit. Typically, the retaining ring is heated to 200-300℃, causing a radial expansion of 0.1-0.3mm. Then, the bar 3 is quickly inserted, and after cooling, an interference fit of 0.02-0.05mm is formed. This process results in a high-strength connection with uniform stress distribution, and avoids the risk of intergranular corrosion caused by welding. It is particularly suitable for manufacturing screen drums made of materials such as stainless steel.

[0047] In this embodiment, the inner top surface of the bar 3 is parallel to the tangential direction of the screen drum.

[0048] It should be noted that the design of the inner top surface being parallel to the tangent of the screen drum ensures the geometric consistency of the screen slot 4 in the circumferential direction, enabling the slurry to obtain uniform screening conditions across the entire circumference of the screen drum. This feature, combined with the other angle designs of the bars 3, constitutes a complete fluid dynamics optimization system, which not only ensures screening accuracy but also maximizes processing capacity and extends the service life of the screen drum.

[0049] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A bar screen frame with multi-stage flow guiding angle, comprising an upper fixing ring (1), a lower fixing ring (2), and a plurality of bars (3) evenly arranged circumferentially, wherein the two ends of the bars (3) are respectively fixed to the upper and lower fixing rings (2), and a screen gap (4) is formed between adjacent bars (3); characterized in that, The cross-section of the bar (3) is polygonal, including at least a slurry-facing surface (5) facing the slurry flow and a slurry-reverse surface (6) facing away from the slurry flow. The slurry-facing surface (5) forms a first acute angle with the radial reference line of the screen drum, and the slurry-reverse surface (6) forms a second acute angle with the radial reference line. The first acute angle is greater than the second acute angle. The range of the first acute angle is 10°-35°, and the range of the second acute angle is 5°-25°.

2. The bar screen frame with multi-stage flow guiding angles according to claim 1, characterized in that, The first acute angle is 16°, and the second acute angle is 10°.

3. A bar screen frame with multi-stage flow guiding angles according to claim 1, characterized in that, The upper fixing ring (1) and the lower fixing ring (2) have annular protrusions (7) on their opposite sides. The end of the bar (3) has annular grooves (8) that are adapted to the annular protrusions (7). The annular protrusions (7) and the annular grooves (8) form a mechanical locking structure by interference fit.

4. A bar screen frame with multi-stage flow guiding angles according to claim 1, characterized in that, The outer wall of the bar (3) is provided with limiting rings (9) that are spaced apart vertically to fix the bar (3), and the bar (3) has outwardly protruding limiting parts (10) on the slurry-facing surface (5) and the slurry-backing surface (6).

5. A bar screen frame with multi-stage flow guiding angles according to claim 4, characterized in that, The limiting ring (9) is provided with a ring-shaped docking groove (11), and the limiting part (10) on the bar (3) is inserted into the docking groove (11).

6. A bar screen frame with multi-stage flow guiding angles according to claim 1, characterized in that, On a cross section perpendicular to the axis of the bar (3), the fan-shaped profile of the bar (3) is formed by connecting at least three sides in sequence, wherein the first side is parallel to the Y-axis, the second side forms a 16° angle with the Y-axis, and the third side forms a 14° angle with the Y-axis.

7. A bar screen frame with multi-stage flow guiding angles according to claim 1, characterized in that, The two adjacent bars (3) are divided into at least three functional sections along their own length direction: the inlet section (12), the screening section (13), and the outlet section (14). The angle of the inlet section (12) is greater than that of the screening section (13), forming a narrow inlet gradually widening channel structure.

8. A bar screen frame with multi-stage flow guiding angles according to claim 1, characterized in that, On the slurry-facing surface (5) of each of the bars (3), there are several micro-grooves (15) extending along the axial direction of the bar (3).

9. A bar screen frame with multi-stage flow guiding angles according to claim 3, characterized in that, The mechanical locking structure is formed by heating and expanding the upper fixing ring (1) and the lower fixing ring (2), assembling the bar (3), and then cooling and shrinking them to form an interference fit.

10. The bar screen frame according to any one of claims 1 to 9, characterized in that, The inner top surface of the bar (3) is parallel to the tangential direction of the screen drum.

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