Slurry pump front protection plate with variable-pitch spiral guide vane

Abstract

The invention provides a slurry pump front guard plate with variable-pitch spiral guide vanes, which belongs to the technical field of slurry pumps and comprises a front guard plate body and a plurality of spiral guide vanes. A liquid inlet channel is formed in the axial middle of the front guard plate body, and an inlet end and an outlet end are arranged at the two ends of the liquid inlet channel in the slurry inflow direction respectively; the multiple spiral guide vanes are arranged in the circumferential direction of the liquid inlet channel at intervals, the rotating direction of the spiral guide vanes is the same as that of the impeller, and a spiral flow channel is formed between every two adjacent spiral guide vanes; the screw pitch of the spiral guide vane is gradually reduced from the inlet end to the outlet end, and the overflowing area of the spiral flow channel is linearly reduced from the inlet end to the outlet end. According to the slurry pump front protection plate with the variable-pitch spiral guide vanes, through the synergistic effect of the variable-pitch spiral guide vanes and the linear decreasing flow channels, the multiple effects of flow stabilization, orientation, speed regulation, loss reduction and the like are achieved, the hydraulic performance and operation stability of a pump body are comprehensively optimized, and the service life of equipment is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of slurry pump technology, and more specifically, relates to a front guard plate for a slurry pump with variable pitch helical guide vanes. Background Technology

[0002] Slurry pumps, as core equipment for solid-liquid two-phase flow transportation, are widely used in mining, metallurgy, power, chemical and other fields. They are mainly used to transport slurry media containing high concentrations of hard solid particles. The front guard plate, as a key flow-through component of the slurry pump, is located at the front end of the impeller. On the one hand, it protects the impeller and prevents slurry backflow. On the other hand, it guides the slurry smoothly into the impeller flow channel and optimizes the inflow state. Its structural design directly determines the operating efficiency, wear resistance and service life of the slurry pump.

[0003] Currently, most conventional slurry pump front guards in the industry adopt a cylindrical inlet channel structure. Although some improved front guards have added circumferentially distributed guide structures to the inner wall of the inlet channel, they are still difficult to adapt to the harsh slurry conveying conditions. Conventional front guards do not have a targeted guide constraint structure for the inlet channel. After the slurry enters from the inlet, it is in a disordered turbulent state and cannot form a matching inlet angle with the high-speed rotating impeller. When the slurry enters the impeller channel, due to the lack of circumferential velocity components and uneven velocity distribution, it will form a violent vortex, local backflow and separation phenomenon at the inlet of the impeller channel. The hard solid particles mixed in are driven by the vortex and repeatedly impact the inner wall of the front guard, the impeller inlet end face and the blade root at irregular angles, forming local high-intensity abrasive wear. This can easily lead to honeycomb pits and perforation failures in the front guard, which greatly shortens the replacement cycle of the flow components. Summary of the Invention

[0004] The purpose of this invention is to provide a front guard plate for a slurry pump with variable pitch spiral guide vanes, which aims to solve the problems caused by the lack of effective flow guidance and constraint in the inlet channel, which leads to easy turbulence of the slurry, mismatch between the inlet angle and the impeller, resulting in eddies, backflow and flow separation, aggravated local wear, and shortened component life.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a slurry pump front guard plate with variable pitch helical guide vanes, comprising: The front guard plate body has a liquid inlet channel in the middle of the axial direction, and the liquid inlet channel has an inlet end and an outlet end at both ends along the slurry flow direction; Multiple helical guide vanes are spaced apart in the circumference of the liquid inlet channel. The rotation direction of the helical guide vanes is the same as that of the impeller. A helical flow channel is formed between two adjacent helical guide vanes to guide the slurry from the inlet end through the outlet end into the working flow channel of the impeller, so that the slurry forms a circumferential velocity component with the same rotation direction as the impeller. The pitch of the spiral guide vane gradually decreases from the inlet end to the outlet end, and the flow area of ​​the spiral flow channel decreases linearly from the inlet end to the outlet end, so as to form linear control of acceleration or diffusion of the slurry passing through the liquid inlet channel.

[0006] In one possible implementation, the base circle of the helical guide vane is perpendicular to the inner wall of the inlet channel, so that the gap between the top of the helical guide vane away from the inner wall of the inlet channel and the inner wall of the inlet channel is constant.

[0007] In one possible implementation, the spiral guide vane has a streamlined curved surface on the side near the inlet end, so that the height of the spiral guide vane increases from the inlet end to the outlet end.

[0008] In one possible implementation, the thickness of the helical guide vane increases from the inlet end to the outlet end.

[0009] In one possible implementation, the thickness of the spiral guide vane increases from the central axis of the liquid inlet channel toward its inner wall.

[0010] In one possible implementation, the plurality of helical guide vanes include one or a combination of long guide vanes and short guide vanes; When the plurality of helical guide vanes consist only of long guide vanes, the plurality of long guide vanes are arranged circumferentially; When the plurality of helical guide vanes consist only of short guide vanes, the plurality of short guide vanes are arranged circumferentially; When the plurality of the spiral guide vanes include long guide vanes and short guide vanes, the long guide vanes and short guide vanes are arranged alternately in a circumferential manner; Wherein, one end of the long guide vane extends out of the inlet end, the other end of the long guide vane extends out of the outlet end, one end of the short guide vane does not extend to the inlet end, and the other end of the short guide vane does not extend out of the outlet end.

[0011] In one possible implementation, one end of the long guide vane extends beyond the outlet end into the central region of the impeller's flow channel.

[0012] In one possible implementation, the same spiral guide vane includes a plurality of short guide vanes, which are arranged sequentially at intervals along the axial direction of the liquid inlet channel, and any one of the short guide vanes is located on the extension line of an adjacent short guide vane.

[0013] The beneficial effects of the slurry pump front guard plate with variable pitch spiral guide vanes provided by this invention are as follows: Compared with the prior art, this solution, by circumferentially setting multiple spiral guide vanes with the same rotation direction as the impeller in the inlet channel at the axial center of the front guard plate body, constructs a directional spiral flow channel using spiral guide vanes, achieving full circumferential directional constraint on the slurry, solving the disordered flow problem caused by the lack of flow guides, forcing the slurry to flow smoothly along a fixed spiral trajectory, avoiding lateral movement and local stagnation, and completely eliminating self-generated eddies in the inlet channel. At the same time, the spiral design of the spiral guide vanes and the impeller in the same direction can pre-assign a circumferential velocity component to the slurry and the impeller synchronously, realizing the adaptation of the slurry inlet angle to the impeller working flow channel, eliminating the flow mismatch problem caused by velocity vector difference, preventing defects such as backflow scouring, flow separation and cavitation, and significantly reducing the disordered impact of the slurry on the flow components.

[0014] More importantly, the spiral guide vane adopts a variable pitch design that gradually decreases from the inlet end to the outlet end. Combined with the structure of linearly decreasing flow area of ​​the spiral flow channel, it can achieve linear control of acceleration and pressure diffusion of the slurry passing through the liquid inlet channel. Compared with conventional constant pitch guide vanes, it can steadily increase the slurry flow velocity without local impact, ensuring that the slurry continuously and smoothly enters the impeller working flow channel. It can also make the slurry pressure rise evenly along the flow direction, eliminate pressure pulsation in the channel, avoid sudden changes in flow velocity and pressure to form local high pressure zone and high speed zone, and prevent local concentrated scouring of solid particles.

[0015] In summary, this solution mitigates wear on flow components by eliminating harmful flow patterns to prevent repeated localized slurry erosion, reducing frontal impact through a smooth inlet angle, and ensuring uniform solid particle distribution to prevent combined damage from cavitation and particle abrasion. This effectively reduces the wear rate of the front liner and impeller, extends the replacement cycle of core components, and lowers maintenance costs. Furthermore, the orderly and stable flow field reduces hydraulic losses caused by eddies and backflow, lowering ineffective energy consumption. Overall, this solution achieves multiple benefits, including flow stabilization, alignment, speed regulation, and loss reduction, through the synergistic effect of variable-pitch helical guide vanes and a linear decreasing flow channel. This comprehensively optimizes the pump's hydraulic performance and operational stability, extending equipment lifespan. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 An assembly diagram of the front guard plate body and the impeller provided in an embodiment of the present invention; Figure 2This is a top view of the front guard plate body provided in an embodiment of the present invention; Figure 3 A cross-sectional view of a slurry pump front guard plate with variable pitch helical guide vanes provided in one embodiment of the present invention; Figure 4 A cross-sectional view of a slurry pump front guard plate with variable pitch helical guide vanes, provided for another embodiment of the present invention.

[0018] In the diagram: 1. Front guard plate body; 2. Liquid inlet channel; 3. Inlet end; 4. Outlet end; 5. Spiral guide vane; 501. Long guide vane; 502. Short guide vane; 6. Streamlined curved surface; 7. Base circle line; 8. Impeller. Detailed Implementation

[0019] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0020] Unless otherwise explicitly specified, the use of terms such as "first," "second," or "third" is intended to distinguish different objects, not to describe a specific order.

[0021] Unless otherwise expressly defined, the use of directional terms such as “center,” “lateral,” “longitudinal,” “horizontal,” “vertical,” “top,” “bottom,” “inner,” “outer,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “clockwise,” “counterclockwise,” “high,” and “low” to indicate orientation or positional relationships is based on the orientation and positional relationships shown in the accompanying drawings and is only for the convenience of describing the invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the specific scope of protection of the invention.

[0022] Please see Figure 1 and Figure 2The present invention will now describe a front guard plate for a slurry pump with variable pitch helical guide vanes. A front guard plate for a slurry pump with variable pitch helical guide vanes includes a front guard plate body 1 and multiple helical guide vanes 5. The front guard plate body 1 has an inlet channel 2 at its axial center, with an inlet end 3 and an outlet end 4 at both ends along the slurry inflow direction. Multiple helical guide vanes 5 are spaced apart circumferentially in the inlet channel 2. The rotation direction of the helical guide vanes 5 is the same as that of the impeller 8. A helical flow channel is formed between adjacent helical guide vanes 5 to guide the slurry from the inlet end 3 through the outlet end 4 into the working flow channel of the impeller 8, so that the slurry forms a circumferential velocity component with the same rotation direction as the impeller 8. The pitch of the helical guide vanes 5 gradually decreases from the inlet end 3 to the outlet end 4, and the flow area constituting the helical flow channel decreases linearly from the inlet end 3 to the outlet end 4, thereby providing linear control for accelerating or diffusing the slurry passing through the inlet channel 2.

[0023] This invention provides a slurry pump front guard plate with variable pitch spiral guide vanes. Compared with the prior art, this solution uses multiple spiral guide vanes 5 arranged at intervals along the circumference of the inlet channel 2 in the axial center of the front guard plate body 1, with the spiral direction consistent with that of the impeller 8. The spiral guide vanes 5 construct a directional spiral flow channel, achieving full circumferential directional constraint on the slurry, solving the disordered flow problem caused by the lack of guide vanes, forcing the slurry to flow smoothly along a fixed spiral trajectory, avoiding lateral movement and local blockage, and completely eliminating self-generated vortices in the inlet channel 2. At the same time, the spiral direction design of the spiral guide vanes 5 and the impeller 8 can pre-assign a circumferential velocity component to the slurry and the impeller 8 synchronously, realizing the adaptation of the slurry inlet angle and the working flow channel of the impeller 8, eliminating the flow mismatch problem caused by velocity vector difference, preventing defects such as backflow scouring, flow separation and cavitation, and significantly reducing the disordered impact of the slurry on the flow components.

[0024] More importantly, the spiral guide vane 5 adopts a variable pitch design that gradually decreases from the inlet end 3 to the outlet end 4. Combined with the structure of linearly decreasing flow area of ​​the spiral flow channel, it can achieve linear control of acceleration and pressure diffusion of the slurry passing through the liquid inlet channel 2. Compared with conventional constant pitch guide vanes, it can steadily increase the slurry flow velocity without local impact, ensuring that the slurry continuously and smoothly enters the working flow channel of the impeller 8. It can also make the slurry pressure rise evenly along the flow direction, eliminate pressure pulsation in the channel, avoid sudden changes in flow velocity and pressure to form local high pressure zone and high speed zone, and prevent local concentrated scouring of solid particles.

[0025] In summary, this solution mitigates wear on flow components by eliminating harmful flow patterns to prevent repeated localized slurry erosion, reducing frontal impact through a smooth inlet angle, and ensuring uniform solid particle distribution to prevent combined damage from cavitation and particle abrasion. This effectively reduces the wear rate of the front liner and impeller 8, extends the replacement cycle of core components, and lowers maintenance costs. Furthermore, the orderly and stable flow field reduces hydraulic losses caused by eddies and backflow, lowering ineffective energy consumption. Overall, this solution achieves multiple benefits, including flow stabilization, alignment, speed regulation, and loss reduction, through the synergistic effect of the variable pitch helical guide vanes 5 and the linear decreasing flow channel. This comprehensively optimizes the pump's hydraulic performance and operational stability, extending equipment lifespan.

[0026] The spiral guide vane 5 adopts a variable pitch design. The pitch is defined as the distance traveled by the spiral of the guide vane in one rotation along the axial direction. The pitch gradually decreases uniformly from the inlet end 3 to the outlet end 4, following a linear law with no abrupt inflection points or step drops. The pitch at the inlet end 3 is set to the maximum value (generally 1.2-1.5 times the diameter of the inlet channel 2) to adapt to the initial guidance of large flow rates of slurry and reduce inlet flow resistance. The pitch at the outlet end 4 is set to the minimum value (generally 0.6-0.8 times the diameter of the inlet channel 2) to match the inlet flow parameters of the impeller 8 and ensure that the slurry accurately enters the impeller 8 flow channel. Directly affected by the variable pitch structure, the cross-sectional area of ​​the spiral flow channel decreases linearly from the inlet end 3 to the outlet end 4. The rate of change of the flow area perfectly matches the rate of decrease of the pitch. The cross-section is an arc-shaped trapezoid, and the slope of the area decrease is set according to the pump head requirement. The higher the head, the larger the slope, and the lower the head, the smaller the slope.

[0027] This variable pitch, linearly reduced flow area design allows for full-process linear control of the slurry passing through the inlet channel 2, achieving two effects: first, smooth acceleration, as the gradually shrinking flow area uniformly increases the axial velocity of the slurry, avoiding impacts and cavitation caused by sudden velocity changes; second, linear pressure diffusion, as the slurry pressure gradually builds up during the spiral flow, with the pressure at the outlet 4 being higher than that at the inlet 3, forming a positive pressure gradient that suppresses cavitation at the impeller 8 inlet and reduces high-pressure slurry backflow. Compared to traditional equal-pitch guide vanes and smooth through-hole structures without guide vanes, this design completely solves the problems of turbulent flow field, pressure pulsation, and high impact loss at the slurry inlet, making it particularly suitable for harsh slurry conveying conditions involving high concentrations, large particles, and high head.

[0028] Please see Figure 1 The spiral guide vane 5 is formed based on the base circle line 7 of the spiral. The base circle line 7 is the inscribed circle of the spiral line of the guide vane. The base circle line 7 is perpendicular to the inner wall of the liquid inlet channel 2. That is, the radial center line of the spiral guide vane 5 is arranged perpendicularly to the axial center line of the liquid inlet channel 2 at 90°. The working surface of the spiral guide vane 5 has no deviation from the inner wall.

[0029] Based on this vertical arrangement, the radial clearance between the top end face of the spiral guide vane 5 away from the inner wall of the inlet channel 2 and the inner wall of the inlet channel 2 remains constant throughout the entire process. The clearance value is set according to the slurry pump specifications and the particle size of the slurry. For example, for fine-particle slurry (particle size ≤ 1 mm), the clearance is controlled at 0.8-1.0 mm; for medium-particle slurry (particle size 1-5 mm), the clearance is controlled at 1.0-1.2 mm; for coarse-particle slurry (particle size ≥ 5 mm), the clearance is controlled at 1.2-1.5 mm. The clearance tolerance does not exceed ±0.1 mm, and there is no local increase or decrease in clearance throughout the entire process.

[0030] This constant gap design serves multiple purposes. First, it suppresses backflow leakage. The constant gap forms a sealing damping layer, preventing the high-pressure slurry generated by the impeller 8 from flowing back to the inlet end 3 of the liquid inlet channel 2 through the gap, thus reducing energy loss and improving the volumetric efficiency of the pump. Second, it optimizes the flow state, avoiding local eddies and secondary flows in the slurry caused by sudden changes in the gap size. It also prevents solid particles from getting stuck and depositing at the gap, reducing scouring and wear on the top of the guide vane and the inner wall, and extending the service life of the guide vane 501. Third, it ensures a uniform flow field. The constant gap makes the boundary layer thickness on the sidewall of the spiral flow channel uniform, and the slurry flow trajectory regular, further improving the stability of the circumferential velocity component transmission.

[0031] Please see Figures 1 to 2 The spiral guide vane 5 is processed into a smoothly transitioning streamlined curved surface 6 on the side near the inlet end 3 of the liquid inlet channel 2. The curved surface adopts a parabolic and arc-shaped composite design. The radius of curvature of the curved surface at the inlet end 3 is set according to the diameter of the liquid inlet channel 2, which is generally 1 / 3 to 1 / 2 of the diameter of the liquid inlet channel 2. The streamlined curved surface 6 gradually becomes thinner and gentler from the root of the spiral guide vane 5 to the top, completely conforming to the flow trajectory of the slurry entering the spiral flow channel from the inlet end 3, realizing the non-collision docking of the slurry and the spiral guide vane 5.

[0032] The streamlined curved surface 6 has a surface roughness Ra≤1.6μm. After polishing, it is free of burrs and scratches, minimizing the impact and erosion wear of slurry (especially large solid particles) on the root of the spiral guide vane 5. This prevents defects such as localized wear pits and cracks on the side of the spiral guide vane 5 near the inlet end 3, extending the overall service life of the spiral guide vane 5. At the same time, the streamlined curved surface 6 can effectively guide the slurry into the spiral flow channel quickly, reducing the flow dead zone and vortex zone at the inlet, lowering the inlet flow resistance, and improving the suction performance of the slurry pump. It is especially suitable for conveying high-viscosity, high-concentration slurries, preventing slurry accumulation and blockage at the inlet end 3.

[0033] Influenced by the streamlined curved surface 6 structure, the overall height of the spiral guide vane 5 gradually increases from the inlet end 3 to the outlet end 4, with the height change following a linear and smooth law, without abrupt changes or drops. The guide vane height at the inlet end 3 is the minimum value, i.e., zero height. The lower inlet height reduces the obstruction of the slurry inflow by the guide vane, reduces impact loss, and avoids large particles of slurry getting stuck at the inlet end 3. The guide vane height at the outlet end 4 reaches its peak, generally 2 / 3 to 3 / 4 of the radius of the inlet channel 2, ensuring that the circumferential velocity component is evenly transmitted to all slurry, avoiding turbulence caused by the lack of circumferential velocity in some areas of the slurry. The increasing guide vane height, combined with the decreasing pitch and decreasing flow area, creates a synergistic effect. The slopes of the three are matched, further optimizing the smoothness of the spiral flow of the slurry, enabling the slurry to complete the entire process optimization from low-resistance entry, smooth guidance to precise outflow from the inlet to the outlet.

[0034] Actual working condition tests show that this streamlined inlet, combined with a height-increasing structure, can reduce slurry inlet impact loss by more than 20%, reduce the wear rate of the guide vane inlet section by more than 15%, and improve the slurry pump suction efficiency by 5%-8%. Compared with traditional guide vanes with equal height and right angles, it has significant performance advantages. At the same time, the processing technology does not require additional complex procedures and can be achieved simply through CNC milling and polishing, making it feasible for mass production.

[0035] Please see Figures 1 to 2 The thickness of the spiral guide vane 5 gradually increases from the inlet end 3 to the outlet end 4 along the axial direction. The thickness change follows a linear gradual change law, without steps or abrupt changes, and the thickness tolerance is controlled within ±0.2mm. As the pitch decreases linearly and the flow area shrinks, the flow velocity of the slurry reaches its peak at the outlet end 4, and it needs to be directly connected to the high-speed rotating impeller 8 to withstand the high-speed scouring of the slurry and the high-frequency impact of solid particles. At the same time, it must also resist the reaction force of the inlet flow field of the impeller 8. The relatively large thickness can fully enhance the structural rigidity and wear resistance of the guide vane.

[0036] The slope of the thickness increase is set according to the total axial length of the spiral guide vane 5 and the pump head parameters. The higher the head and the greater the slurry velocity, the greater the slope of the increase, so as to further improve the strength of the outlet end 4. In scenarios with lower head and milder operating conditions, the slope of the increase can be appropriately reduced to control material consumption while ensuring strength. For example, for a medium-sized guide vane with an axial length of 80mm, the thickness of the inlet end 3 is 5mm and the thickness of the outlet end 4 is 10mm. The thickness increases by 0.625mm every 10mm along the axial direction to achieve a smooth and gradual change, avoiding stress concentration or flow field disturbance caused by abrupt changes in thickness.

[0037] The advantages of this axially increasing thickness design, combined with the variable pitch and linearly monotonically decreasing flow area structure, adapt to the full-process changes of the slurry within the flow channel: Low-resistance flow guide at inlet end 3: The minimum thickness design minimizes the occupancy of the guide vane on the flow area of ​​the liquid inlet channel 2. Combined with the streamlined curved surface 6 and low height design, it enables unobstructed and low-impact entry of slurry, effectively reducing inlet flow resistance and improving the suction performance of the slurry pump. It is especially suitable for working conditions with low net positive suction head (NPSH). Smooth transition in the middle section: The thickness gradually increases, and the slurry flow rate and pressure are matched simultaneously with the slow increase, so that the strength of the spiral guide vane 5 increases synchronously with the increase of force, avoiding micro-deformation in the middle section due to insufficient strength, ensuring the dimensional accuracy of the spiral flow channel, and maintaining the smoothness of slurry flow. The outlet end 4 features enhanced wear resistance: the maximum thickness design improves the excellent impact, bending, and erosion resistance of the spiral guide vane 5 at the outlet end 4. It can withstand the high-speed scouring of high-concentration slurry and the high-frequency impact of large solid particles, preventing failures such as curling, cracking, breakage, or localized wear through the spiral guide vane 5 at the outlet end 4. At the same time, the thickened spiral guide vane 5 at the outlet end 4 can form a more stable flow boundary, allowing the slurry to enter the impeller 8 flow channel in a more regular flow pattern, further reducing secondary impacts between the slurry and the impeller 8 blades, and extending the service life of the impeller 8 and the spiral guide vane 5.

[0038] The axial incremental structure of this embodiment is more in line with the actual working mechanism of the slurry pump. According to the actual test of the tailings conveying operation in the mine, the wear rate of the outlet end 4 of the spiral guide vane 5 with this structure is reduced by more than 30%, and no deformation or breakage occurs. At the same time, the flow resistance at the inlet end 3 does not increase significantly, thus achieving the dual optimization goal of low inlet resistance and strong outlet.

[0039] Please see Figures 1 to 2 The thickness of the spiral guide vane 5 gradually increases radially from the central axis of the inlet channel 2 towards the inner wall of the channel, exhibiting a shape that is thinner at the inside and thicker at the outside. The top of the spiral guide vane 5 near the central axis has a thin edge structure with the smallest thickness. The smooth thin edge can significantly reduce the resistance of the slurry flow and avoid the formation of eddies and flow separation at the top. At the same time, in conjunction with the axially increasing design, the radial gradient of the top thickness is synchronized with the axial increase, always maintaining a smooth curved surface shape. The root of the spiral guide vane 5 near the inner wall of the channel has a thickened structure with the largest thickness. The root and the inner wall of the inlet channel 2 are smoothly transitioned with a large rounded corner with a radius of R5-R8, which increases the contact area between the spiral guide vane 5 and the front guard plate body 1, disperses the stress generated by the impact of solid particles, and improves the erosion resistance, bending resistance, and fracture resistance of the spiral guide vane 5.

[0040] This radially varying thickness structure, in synergy with the axially increasing thickness design, achieves optimized performance across the entire region. The axial direction adapts to the increasing flow velocity and impact force of the slurry, strengthening the outlet end; the radial direction adapts to the stress distribution characteristics, enhancing the root bearing capacity while reducing top flow resistance. Compared to single-direction thickness variations, the bidirectional varying thickness guide vane significantly improves structural rationality and adaptability to operating conditions, making it particularly suitable for harsh slurry conditions involving high concentrations, large particles, and strong impacts. It effectively prevents root wear and cracking, top deformation and curling, and other malfunctions.

[0041] From the perspective of flow field mechanism analysis, the radially gradual thickness makes the sidewall curvature of the spiral flow channel more closely match the spiral flow trajectory of the slurry, reducing boundary layer separation and lowering the energy loss of the slurry flow. At the same time, the thickened root design can improve the connection stiffness between the front guard plate body 1 and the guide vane, reducing vibration during pump operation and lowering noise levels. This bidirectional gradual structural design can be achieved without changing the original casting and machining processes, only by adjusting the mold cavity size, and has strong engineering practicality.

[0042] The multiple helical guide vanes 5 have three structures: a single long guide vane 501, a single short guide vane 502, and a combination of both long and short guide vanes 501.

[0043] When multiple spiral guide vanes 5 include only long guide vanes 501 (not shown in the attached diagram), the multiple long guide vanes 501 are evenly arranged at equal angles around the circumference of the inlet channel 2. The number of long guide vanes 501 is set to 4 / 6 / 8 pieces according to the pump body specifications. The spiral flow channel width and flow area between adjacent long guide vanes 501 are completely consistent. This arrangement is suitable for high-flow, high-head, and high-concentration slurry pump scenarios. The pre-guided flow and post-extension sections of the long guide vanes 501 can control the slurry flow field throughout the entire process, and the thickened extension section at the outlet end 4 can directly resist the strong impact of the impeller inlet 8. The guiding effect and structural reliability are both optimized, making it suitable for harsh working conditions such as mine tailings and metallurgical slurries.

[0044] Please see Figure 4 When multiple spiral guide vanes 5 consist only of short guide vanes 502, the multiple short guide vanes 502 are evenly arranged at equal angles along the circumference of the inlet channel 2. This arrangement is suitable for low-flow, low-head, fine-particle / clean slurry pump scenarios. The axial thickness increasing design of the short guide vanes 502 ensures the flow guiding strength in the middle section while reducing the overall volume, reducing flow obstruction, lowering flow resistance, and improving the pump's suction performance. At the same time, it simplifies the structure and reduces casting difficulty, making it suitable for mild working conditions such as chemical liquids and fine-particle slurries.

[0045] Please see Figure 3When multiple helical guide vanes 5 include long guide vanes 501 and short guide vanes 502, the long guide vanes 501 and short guide vanes 502 are arranged alternately in a circumferential manner, that is, one long guide vane 501 and one short guide vane 502 are arranged in a cycle to ensure a symmetrical flow field and no flow deviation. The long guide vane 501 plays the role of the main flow, responsible for controlling the slurry and transmitting the circumferential velocity throughout the process, and its outlet end 4 has a thickened structure to resist the core impact; the short guide vane 502 serves as an auxiliary guide vane, responsible for diverting the slurry, breaking up local eddies, and filling the flow field gaps between the long guide vanes 501 to avoid the occurrence of flow dead zones in the flow channel.

[0046] Specifically, the axial length of the long guide vane 501 is greater than the total axial length of the inlet channel 2. One end of the guide vane extends out of the inlet end 3 of the inlet channel 2, forming a pre-guided section to pre-guide the slurry; the other end extends out of the outlet end 4 of the inlet channel 2, forming a rear extension section that extends into the inlet area of ​​the impeller 8. The thickness of the long guide vane 501 increases linearly along the axial direction from the inlet extension end to the outlet extension end, with the thickness at the inlet extension end being the minimum and the thickness at the outlet extension end reaching the maximum, ensuring that the key parts extending to the impeller 8 flow channel have the strongest wear resistance.

[0047] Specifically, the axial length of the short guide vane 502 is less than the total axial length of the inlet channel 2. Neither end of the guide vane extends to the inlet end 3 or the outlet end 4; its placement is concentrated in the middle section of the inlet channel 2, providing only mid-section guidance for the slurry. Its length is generally 1 / 2 to 2 / 3 of that of the long guide vane 501. The thickness of the short guide vane 502 also increases linearly along its axial length from the side near the inlet end 3 to the side near the outlet end 4. The thickness start and end points match the slurry stress characteristics at their respective flow channel locations. The slurry flow velocity in the middle section of the flow channel is moderate. Therefore, the overall thickness range of the short guide vane 502 is slightly smaller than that of the long guide vane 501, ensuring strength while further reducing flow resistance.

[0048] Preferably, the long guide vane 501 extends axially from the outlet end 4 of the liquid inlet channel 2 to the central region of the impeller 8 flow channel. This extension section is the thickest part of the long guide vane 501, and its thickness is consistent with that of the outlet end 4, making it the part with the highest strength and strongest wear resistance of the entire guide vane. The width and pitch of the spiral guide vane 5 in the extension section are consistent with the main structure of the outlet end 4, and the end is rounded to avoid scratching the impeller 8 blades and further optimize the slurry outflow trajectory, reducing local eddies.

[0049] The extended section of the long guide vane 501 is aligned with the inlet end of the impeller 8 blades, and the spiral line of the extended section is perfectly matched with the inlet angle of the impeller 8 blades. This allows the slurry to flow directly into the impeller 8 flow channel along the working surface of the impeller 8 blades after it flows out of the spiral channel. The spiral flow state of the slurry directly transitions to the working state of the impeller 8, without any abrupt change in the flow field or velocity loss. This completely eliminates the transition gap and transition vortex zone between the front guard plate outlet and the impeller 8 inlet.

[0050] Furthermore, the extension section, being the thickest part, directly withstands the strong impact from the impeller 8 inlet and the scouring of high-concentration slurry, completely solving the problem of easy wear and breakage of traditional guide vane extension sections, and extending the service life of guide vane 501 and impeller 8. In addition, the local high-pressure zone formed by the extension section can effectively suppress the formation of the cavitation core zone at the impeller 8 inlet, reducing the risk of cavitation damage.

[0051] Please see Figure 4 Within the same set of 5 spiral guide vanes, multiple short guide vanes 502 (generally 2-3 sections) are arranged sequentially at intervals along the axial direction of the liquid inlet channel 2. The axial spacing between adjacent short guide vanes 502 is set according to the particle size of the slurry. For example, the spacing is larger (25-30mm) for large slurry particles to avoid particle jamming; the spacing is smaller (15-20mm) for fine slurry particles to ensure continuous flow. The spacing is uniform and without deviation, and the consistency of batch production is achieved through precise positioning by the mold.

[0052] In this system, any short guide vane 502 is located on the axial extension line of the adjacent short guide vane 502. The spiral angle, spiral direction, and pitch of all short guide vanes 502 are completely consistent, forming a continuous and complete segmented spiral guiding trajectory without misalignment, deviation, or breakpoints. This ensures that the slurry moves continuously in a spiral motion along the segmented short guide vanes 502, and the flow field state is not affected by the segmentation.

[0053] Taking a single structure comprising three short guide vanes 502 as an example, along the slurry flow direction, the thickness of the first short guide vane 502 at its inlet side is the minimum, while the thickness at its outlet side increases to the first intermediate value; the thickness of the second short guide vane 502 at its inlet side is consistent with the first intermediate value, while the thickness at its outlet side increases to the second intermediate value; the thickness of the third short guide vane 502 at its inlet side matches the second intermediate value, while the thickness at its outlet side increases to the maximum value of the entire group of segmented short guide vanes 502. This "segmented continuous increase" design ensures that the thickness variation of the entire group of segmented short guide vanes 502 is completely synchronized with the increasing velocity and impact force of the slurry in the flow channel. This retains the advantages of segmented structures in terms of anti-clogging and low resistance, while also achieving a gradual increase in strength and improving wear resistance.

[0054] Furthermore, the segmented spacing allows large slurry particles to pass through smoothly, preventing particle jamming and flow channel blockage caused by the long guide vane 501 blocking the entire flow path. The segmented, continuously increasing thickness design ensures that the strength of each short guide vane 502 is adapted to the stress of the slurry in its respective area, with the thickest section of the short guide vane 502 resisting the scouring and impact of high-speed slurry. In addition, the segmented structure reduces the contact area between the short guide vane 502 and the slurry, reducing frictional resistance and energy loss.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A front guard plate for a slurry pump with variable pitch helical guide vanes, characterized in that, include: The front guard plate body (1) has a liquid inlet channel (2) in the middle of the axial direction. The liquid inlet channel (2) has an inlet end (3) and an outlet end (4) at both ends along the slurry flow direction. Multiple spiral guide vanes (5) are spaced apart in the circumference of the liquid inlet channel (2). The spiral direction of the spiral guide vanes (5) is the same as that of the impeller (8). A spiral flow channel is formed between two adjacent spiral guide vanes (5) to guide the slurry from the inlet end (3) through the outlet end (4) into the working flow channel of the impeller (8) so that the slurry forms a circumferential velocity component with the same spiral direction as the impeller (8). The pitch of the spiral guide vane (5) gradually decreases from the inlet end (3) to the outlet end (4), and the flow area of ​​the spiral flow channel decreases linearly from the inlet end (3) to the outlet end (4) to form linear control of acceleration or diffusion of the slurry passing through the liquid inlet channel (2).

2. The slurry pump front guard plate with variable pitch spiral guide vanes as described in claim 1, characterized in that, The base circle (7) of the spiral guide vane (5) is perpendicular to the inner wall of the liquid inlet channel (2) so that the gap between the top of the spiral guide vane (5) away from the inner wall of the liquid inlet channel (2) and the inner wall of the liquid inlet channel (2) is constant.

3. The slurry pump front guard plate with variable pitch spiral guide vanes as described in claim 1, characterized in that, The spiral guide vane (5) has a streamlined curved surface (6) on the side near the inlet end (3) so that the height of the spiral guide vane (5) increases from the inlet end (3) to the outlet end (4).

4. The slurry pump front guard plate with variable pitch spiral guide vanes as described in claim 1, characterized in that, The thickness of the spiral guide vane (5) increases from the inlet end (3) to the outlet end (4).

5. The slurry pump front guard plate with variable pitch spiral guide vanes as described in claim 1, characterized in that, The thickness of the spiral guide vane (5) increases from the central axis of the liquid inlet channel (2) toward its inner wall.

6. A slurry pump front guard plate with variable pitch spiral guide vanes as described in any one of claims 1-5, characterized in that, The plurality of said spiral guide vanes (5) include one or a combination of two of long guide vanes (501) and short guide vanes (502); When the plurality of spiral guide vanes (5) include only long guide vanes (501), the plurality of long guide vanes (501) are arranged circumferentially; When the plurality of spiral guide vanes (5) consist only of short guide vanes (502), the plurality of short guide vanes (502) are arranged circumferentially; When the plurality of the spiral guide vanes (5) include long guide vanes (501) and short guide vanes (502), the long guide vanes (501) and the short guide vanes (502) are arranged alternately in a circumferential manner; One end of the long guide vane (501) extends out of the inlet end (3), and the other end of the long guide vane (501) extends out of the outlet end (4). One end of the short guide vane (502) does not extend to the inlet end (3), and the other end of the short guide vane (502) does not extend out of the outlet end (4).

7. A slurry pump front guard plate with variable pitch helical guide vanes as described in claim 6, characterized in that, The long guide vane (501) extends from one end of the outlet end (4) to the central region of the flow channel of the impeller (8).

8. A slurry pump front guard plate with variable pitch spiral guide vanes as described in claim 6, characterized in that, The same spiral guide vane (5) includes a plurality of short guide vanes (502), which are arranged sequentially at intervals along the axial direction of the liquid inlet channel (2), and any one of the short guide vanes (502) is located on the extension line of the adjacent short guide vane (502).

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