Slurry pump impeller and manufacturing method thereof

Abstract

The invention relates to a slurry pump impeller and a manufacturing method thereof, and belongs to the technical field of pump impellers. The slurry pump impeller comprises a metal core bar and a plurality of blades. The metal core bar comprises a pair of first cover plates and a plurality of supporting pieces. The pair of first cover plates are oppositely arranged along a first direction; the supporting sheet is located between the pair of first cover plates, and the supporting sheet is fixedly connected with the cover plates; each blade is provided with a root part and an end part along the length direction; the multiple blades are arranged in a circumferential array with the first direction as the axis. The root part is closer to the axis of the plurality of blades than the end part; the supporting sheets penetrate through the blades, and the supporting sheets support the blades; the support sheet is configured to be closer to the end part among the end part and the root part; and the plurality of blades are in one-to-one correspondence with the plurality of supporting sheets. The slurry pump impeller provided by the embodiment of the invention has relatively long service life.

Description

Technical Field

[0001] This application relates to the technical field of impellers for pumps, and more specifically, to a slurry pump impeller and a manufacturing method thereof. Background Art

[0002] Phosphorus chemical industry is an industrial system that uses phosphate rock as raw material to produce phosphorus-containing products through chemical processing. Phosphorus chemical production will generate phosphogypsum tailings. In order to prevent phosphogypsum tailings from polluting the environment, it is necessary to treat phosphogypsum tailings. Phosphogypsum tailings are solid particles. In order to facilitate the transportation of phosphogypsum tailings, generally, solid phosphogypsum tailings are mixed with phosphogypsum slurry water to form a slurry, and the phosphogypsum tailings are wet-discharged through a transfer pump.

[0003] A centrifugal transfer pump pumps the slurry through the pump casing. The impeller inside the pump rotates at high speed to generate centrifugal force, which pushes the slurry to flow at high speed, thereby transporting the phosphogypsum tailings. As the production volume of the phosphorus chemical industry increases year by year, the height of the phosphogypsum storage yard also increases year by year, and the distance of the phosphogypsum tailings is getting farther and farther. Therefore, the requirement for the delivery head of the phosphogypsum tailings transfer pump is also greater. In order to increase the delivery head of the transfer pump, it is necessary to increase the diameter of the impeller of the transfer pump. However, the phosphogypsum slurry water mixed with the phosphogypsum tailings (in order to be environmentally friendly, some factories will use more acidic tailings return water instead of phosphogypsum slurry water) has a strong acidity, which will corrode the impeller. Therefore, the impeller used in the process of transporting phosphogypsum tailings is generally made of materials with good corrosion resistance (such as ceramics). However, this type of material is brittle, and when the stress at the edge of the impeller made is relatively large, it is easy to break. Therefore, the diameter of the impeller made of this type of material cannot be too large.

[0004] In order to meet the increasing demand for the delivery head of the transfer pump during the transportation of phosphogypsum tailings, a metal skeleton with high strength can be set inside the impeller to inhibit the rupture of the blades through the high strength of the metal skeleton. However, during the use of the transfer pump, the stress on the root of the impeller blade is relatively low (the centrifugal force and bending moment are small), but the number of cycles is extremely high. The metal skeleton at the root part of the blade will accumulate fatigue damage relatively quickly during the process of high-speed cyclic stress, and then be damaged, resulting in a relatively short overall life of the blade. Summary of the Invention

[0005] The purpose of this application is to provide a slurry pump impeller with a long service life to improve the above problems in view of the above problems.

[0006] This application is achieved by the following technical solutions: In the first aspect, the present application provides a slurry pump impeller, which includes a metal core and multiple blades, the metal core including a pair of first cover plates and multiple support plates; the pair of first cover plates are arranged opposite to each other along a first direction; the support plates are located between the pair of first cover plates, and the support plates are fixed to the cover plates; the blades are provided with roots and ends along their length directions; wherein the multiple blades are arranged in a circular array with the first direction as the axis; the roots are closer to the axes of the multiple blades than the ends; the support plates pass through the blades, and the support plates support the blades; the support plates are configured to be closer to the ends between the ends and the roots; the multiple blades correspond one-to-one to the multiple support plates.

[0007] In the technical solution of the embodiment of the present application, the stress cycle to which the slurry pump impeller is subjected during use is mainly caused by rotational periodic loads and vibration loads. The rotational periodic load is that each part of the impeller undergoes a complete stress cycle for each rotation of the impeller. The vibration load is a high-frequency alternating stress caused by water flow disturbance, mechanical resonance or external excitation. However, the effect of the rotational load on the root and end of the blade is: the number of cycles at the root and end is the same (once per rotation), but the stress amplitude increases from the root to the end; and the effect of the vibration load on the root and end of the blade is: since the constraint effect on the blade decreases from the root to the end, the root may be subjected to more frequent stress fluctuations due to the constraint effect. In summary, the stress (such as centrifugal force) borne by the end of the blade is large, but the number of cycles mainly comes from the rotation speed, and the frequency is low. The stress (such as centrifugal force) borne by the root of the blade is small, but the number of cycles comes from both the rotation speed and vibration, and the frequency is high.

[0008] In traditional designs, the root of the blade suffers from rapid fatigue failure of the metal skeleton due to cyclic stress concentration. This application changes the stress distribution by placing the support plate closer to the blade end. The metal support plate with a high fatigue limit supports the end, while the root is supported by the fatigue-resistant material of the blade itself, allowing the end to withstand more centrifugal force. The root is loaded by the support plate close to the end, reducing the local stress amplitude and subjecting the root to less stress. The fatigue-resistant properties of the blade's own material (such as ceramics, carbon fiber composites, etc.) allow the root to resist fatigue damage during high-speed cyclic stress, thereby extending the overall life of the blade.

[0009] The squirrel cage structure formed by the combination of the metal core and the cover plate and the support plate improves the overall rigidity of the impeller, especially suppressing the bending deformation of the blades caused by centrifugal force under high-speed rotation; for blades made of brittle materials (such as ceramics), the support of the metal core can reduce the stress concentration at the blade end, avoid brittle fracture, and allow the impeller diameter to be increased to meet high head requirements.

[0010] The blade circumferential array design has the support pieces corresponding to the blades one by one. The evenly distributed support pieces ensure that each blade is evenly stressed, reducing the risk of local overload and improving the smooth operation of the impeller.

[0011] In some embodiments, a plurality of through holes are provided on both the support pieces and the first cover plate.

[0012] In the technical solution of the embodiment of the present application, a plurality of through holes are provided on both the support pieces and the first cover plate. The through holes can significantly reduce the weight of the support pieces and the cover plate, thereby reducing the overall mass of the metal core, and reducing the cyclic load on the blade root caused by the centrifugal force during high-speed rotation. After the weight is reduced, the bending moment and inertial force borne by the root of the blade are reduced, further delaying the accumulation of fatigue damage at the root and improving the service life of the slurry pump impeller provided by the present application. The through holes provide mechanical anchoring points for the material of the blade during the manufacturing process, and the slurry or binder penetrates into the holes to form a "locking structure", improving the interfacial bonding strength and reducing the risk of separation between the metal core and the blade.

[0013] In some embodiments, the dimension from the end of the support piece near the root to the end near the tip is the length dimension of the support piece; the axes of the plurality of blades pass through the axis center of the first cover plate; the axis center of one of the pair of first cover plates is connected to the driving member, and the axis center of the other is provided with a liquid inlet; the length dimension of the side of the support piece close to the driving member is R1; the length dimension of the side of the support piece close to the liquid inlet is R2; and it satisfies R1 > R2.

[0014] In the technical solution of the embodiment of the present application, the first cover plate directly connected to the driving member in the metal core is strongly restricted by the driving member, while the other first cover plate is at a certain distance from the driving member and is weakly controlled by the driving member. When R1 > R2, the length dimension of the end of the support piece close to the driving member is greater than the dimension of the end of the support piece close to the liquid inlet. The dimension of the end of the support piece close to the liquid inlet is smaller, so that the weight of the part of the metal core far from the driving member is smaller, and thus the inertia of this part is smaller, which can adapt to the weak control effect of the driving member, thereby avoiding the vibration of the part of the metal core far from the driving member relative to the driving member and affecting the normal rotation of the impeller; furthermore, after the material enters the impeller, it will continue to flow axially into the impeller under the action of the negative pressure suction until it is blocked by the first cover plate connected to the driving member and changes the flow direction. After the material contacts the first cover plate connected to the driving member, it will continue to contact the blade. That is, the part of the impeller close to the driving member will share this part of the impact force, and the length dimension of the end of the support piece close to the driving member is larger, which can provide a relatively reliable support effect for this part of the impeller and improve the service life of the impeller.

[0015] In some embodiments, the end of the support piece near the tip is flush with the outer peripheral surface of the first cover plate.

[0016] In the technical solution of the embodiment of the present application, one end of the support piece close to the end is flush with the outer peripheral surface of the first cover plate, so that the size of the space at the center of the plurality of support pieces gradually decreases from the suction port to the driving member, and the shape of the support piece is adapted to the shape of the impeller, so that the size of the opening at the center of the impeller gradually decreases from the suction port to the driving member. This setting makes the channel through which the material flows gradually narrow during the process of entering the impeller until it is blocked and deflected, allowing the water flow to concentrate and rush, reducing energy loss.

[0017] In some embodiments, it further includes a pair of second cover plates; the pair of second cover plates are arranged opposite to each other along the first direction; the first cover plate is located inside the second cover plate; the blades are located between the pair of second cover plates, and the blades are fixedly connected to the second cover plates.

[0018] In the technical solution of the embodiment of the present application, on the one hand, the second cover plate serves as an outer protective cover, wrapping the first cover plate inside, preventing the paste formed by the mixture of phosphogypsum tailings and phosphogypsum slurry water (or tailings return water) from directly scouring the metal first cover plate, and significantly reducing the risk of corrosion and damage to the first cover plate. On the other hand, the blades are fixedly connected to the second cover plates, so that part of the centrifugal force is transmitted to the wheel shaft connected to the impeller of the slurry pump through the second cover plates, reducing the stress amplitude at the root, thereby reducing the risk of root damage.

[0019] In some embodiments, both ends of the support piece extend into the pair of second cover plates and are respectively connected to the pair of first cover plates.

[0020] In the technical solution of the embodiment of the present application, both ends of the support piece are fixedly connected to the first cover plate and the second cover plate respectively, forming a rigid connection penetrating the inner and outer layers, integrating the metal core with the second cover plate into a three-dimensional support framework, enhancing the overall bending stiffness of the impeller, and suppressing the radial deformation of the blades under high centrifugal force. The second cover plate and the blades wrap the entire metal core inside, preventing the paste formed by the mixture of phosphogypsum tailings and phosphogypsum slurry water (or tailings return water) from contacting the metal core. The support piece passes through the second cover plate and is connected to the first cover plate, forming a physical anchoring point. Even if microcracks occur at the connection interface between the outer second cover plate and the blades, the internal support piece and the first cover plate can still provide mechanical support, preventing crack propagation and enhancing the structural stability of the slurry pump impeller.

[0021] In some embodiments, the material of the blades is carbon fiber composite material.

[0022] In the technical solution of the embodiment of the present application, in traditional ceramic blades, due to their high brittleness, the impeller diameter is limited, making it difficult to meet the high head requirements. The material of the blades provided in the present application is carbon fiber composite material. The tensile strength of carbon fiber composite material (CFRP) is higher than that of steel, and it also has excellent impact toughness, can withstand greater centrifugal force, allows the impeller diameter of the slurry pump to be larger, thereby increasing the conveying head. The density of the carbon fiber composite material is relatively low, which can reduce the weight of the blade, reduce the load of the centrifugal force on the metal core, thereby reducing the stress amplitude at the root and extending the fatigue life. The carbon fiber composite material also has extremely high corrosion resistance, which can effectively prevent the blade from being corroded by phosphogypsum slurry water (or tailings return water).

[0023] In a second aspect, the present application provides a manufacturing method for a slurry pump impeller for manufacturing the slurry pump impeller of the first aspect. The manufacturing method of the slurry pump impeller includes: Step S100: Connect one first cover plate to one end of a plurality of support pieces; Step S200: Install a disposable inner mold between the plurality of support pieces, and then connect another first cover plate to the other end of the plurality of support pieces to obtain a metal core; Step S300: Place the metal core with the disposable inner mold in a molding die and perform injection molding to obtain a slurry pump impeller.

[0024] In the technical solution of the embodiment of the present application, in Step S100, one end of the plurality of support pieces is connected to one of a pair of first cover plates to fix the positions of the plurality of support pieces. In Step S200, the disposable inner mold is installed between the plurality of support pieces from the end where the support pieces are not connected to the cover plate, and then another first cover plate is connected to the other end of the plurality of support pieces to obtain a metal core. The inner mold precisely fills the gaps between the support pieces, ensuring that non-metallic materials (such as carbon fiber prepreg, corrosion-resistant engineering plastics) uniformly wrap the metal core during injection molding, avoiding stress concentration caused by eccentricity or uneven wall thickness. Finally, in Step S300, the metal core with the disposable inner mold is placed in a molding die and injection molding is performed to obtain a slurry pump impeller. The other first cover plate is connected to the support pieces only after the disposable inner mold is installed between the support pieces, simplifying the installation process of the disposable inner mold and facilitating the operator to adjust and determine the position of the disposable inner mold, reducing the risk of eccentricity or uneven wall thickness of the metal core. Using a single disposable inner mold to complete the molding of the entire inner cavity of the slurry pump impeller makes the wall of the inner cavity of the obtained slurry pump impeller flat and smooth, avoiding burrs, unevenness, etc. that may occur in the inner cavity made by piecing together multiple inner molds. The manufacturing method of the slurry pump impeller provided in the present application realizes the precision molding of high-head and large-size impellers through the method of prefabricating the metal core + assisting injection molding with an inner mold, providing a manufacturing solution for slurry pump impellers that is efficient, highly reliable, and has low environmental load.

[0025] In some embodiments, between step S200 and step S300, there is also step S400: providing a transition layer on the forming surface of the metal core; wherein, the forming surface is the surface of the metal core that contacts the forming liquid through the transition layer; the transition layer is composed of M layers of transition materials, M≥3; the innermost N layers of transition materials are the first material, the first material has elasticity, M>N≥1, and the first material is in close contact with the forming surface; the outermost K layers of transition materials are the second material, the second material has adhesiveness, M>K≥1; the L layers of transition materials located between the first material and the second material are the third material, the third material has a low thermal conductivity, M>L≥1, N+K+L≤M.

[0026] In the technical solution of the embodiment of the present application, when injecting the forming liquid, since the third material has a relatively low thermal conductivity, the amount of heat absorbed by the metal core from the forming liquid and the resulting thermal expansion of its own temperature are reduced. The first material deforms as the metal core expands. In the cooling stage of the forming liquid, the metal core shrinks in volume due to the decrease in its own temperature. The transition layer adheres to the forming surface of the metal core and remains in close contact. The first material deforms synchronously with the shrinkage of the metal core. At the same time, the second material has high fluidity and self-sealing properties. The second material can fill the gap between the formed body formed after the cooling of the forming liquid and the third material, so that the transition layer can fill the gap vacated after the shrinkage of the metal core and the gap that appears after the cooling and hardening of the forming liquid, reducing the probability of defects such as cavities or holes between the forming liquid and the metal core during the cooling and hardening stage of the forming liquid.

[0027] In some embodiments, the first material is silicone rubber.

[0028] In the technical solution of the embodiment of the present application, the first material is silicone rubber, which has the characteristics of low elastic modulus and excellent flexibility. It can stably adhere to the metal core and can compensate for the thermal expansion amount during the injection molding process of the metal core through its own elastic deformation, thereby avoiding the situation of cavities between the metal core and the blade and the second cover due to the thermal expansion and contraction of the metal core, and improving the overall density of the slurry pump impeller.

[0029] In some embodiments, the second material is an epoxy resin-based nanocomposite.

[0030] In the technical solution of the embodiment of the present application, the second material is an epoxy resin-based nanocomposite. The epoxy resin-based nanocomposite can infiltrate the surfaces of the blade and the second cover facing the metal core and form a dense structure after curing. Its high adhesiveness can enhance the interfacial bonding force between the metal core and the blade and the second cover, reduce the defects on the surfaces of the blade and the second cover facing the metal core, and improve the connection stability between the metal core and the blade and the second cover.

[0031] In some embodiments, the third material is a ceramic-based coating.

[0032] In the technical solution of the embodiment of the present application, the third material is a ceramic-based coating, which has a low thermal conductivity (<30 W / m·K) and high-temperature stability (>1000 °C). It can effectively block the heat conduction of the forming liquid to the metal core, reduce its thermal expansion amplitude, and prevent the expansion amount of the metal core from exceeding the compensable amount of the first material, thereby reducing the risk of cavities appearing between the metal core and the blade and the second cover plate.

[0033] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0035] Figure 1 Schematic diagram of the overall structure of the slurry pump impeller provided by some embodiments of the present application;

[0036] Figure 2 Side view of the slurry pump impeller provided by some embodiments of the present application;

[0037] Figure 3 For Figure 2 Cross-sectional view at A-A in

[0038] Figure 4 Schematic diagram of the structure of the metal core provided by some embodiments of the present application;

[0039] Figure 5 Flowchart of the manufacturing method of the slurry pump impeller provided by some embodiments of the present application;

[0040] Figure 6 Cross-sectional schematic diagram of the transition layer provided by some embodiments of the present application;

[0041] Figure 7 Flowchart of the manufacturing method of the slurry pump impeller provided by other embodiments of the present application;

[0042] Figure 8 Schematic diagram of the structure of the metal core provided by other embodiments of the present application;

[0043] Icon: 1 - Metal core; 10 - First cover plate; 11 - Support piece; 12 - Forming surface; 13 - Through hole; 2 - Blade; 20 - Root; 21 - End; 3 - Second cover plate; 4 - Transition layer; 40 - First material; 41 - Second material; 42 - Third material; X - First direction. Detailed implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are part of the embodiments of the present application, rather than all of them. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0045] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the description of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of this application or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0046] Referring to "embodiments" in this application means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The appearance of this phrase in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in this application can be combined with other embodiments.

[0047] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0048] In this application, the term "and / or" is merely a description of the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this application, the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0049] In this application, "multiple" means two or more (including two). Similarly, "multiple groups" means two or more groups (including two groups), and "multiple pieces" means two or more pieces (including two pieces).

[0050] According to some embodiments of this application, optionally, as Figures 3 to 4 shown, this application provides a slurry pump impeller. The slurry pump impeller includes a metal core 1 and multiple blades 2. The metal core 1 includes a pair of first covers 10 and multiple support pieces 11; the pair of first covers 10 are oppositely arranged along the first direction X; the support pieces 11 are located between the pair of first covers 10, and the support pieces 11 are fixedly connected to the covers; the blades 2 are provided with a root 20 and an end 21 along their length direction; wherein, the multiple blades 2 are circumferentially arrayed with the first direction X as the axis; the root 20 is closer to the axis of the multiple blades 2 than the end 21; the support pieces 11 pass through the blades 2, and the support pieces 11 support the blades 2; the support pieces 11 are configured to be closer to the end 21 among the end 21 and the root 20; the multiple blades 2 correspond to the multiple support pieces 11 one by one.

[0051] The material of the metal core 1 can be but is not limited to 2205 duplex stainless steel, CD4MCu duplex stainless steel, etc.

[0052] The material of the blades 2 can be but is not limited to ceramics, carbon fiber reinforced ceramics, carbon fiber composite materials, etc.

[0053] One of the first covers 10 can be connected to the rotating shaft.

[0054] The diameter of the slurry pump impeller provided by this application is 700 - 900 mm, the rotational speed n = 980 rpm. The pump equipped with the slurry pump impeller provided by this application needs to withstand a pressure of 4.0 MPa, with a flow rate of 900 - 1300 m³ / h and a head of 70 - 90 m.

[0055] The support pieces 11 and the covers can be connected by welding, bonding, or integrally formed; or the support pieces 11 can be integrally formed with one of the two covers, and connected to the other by welding or bonding, so that the end of the support piece 11 that is not connected to the cover can first pass through the blade 2, and then be connected to the cover by welding or bonding, reducing the assembly difficulty.

[0056] The blades 2 cover the support sheet 11 to prevent the slurry formed by the mixture of phosphogypsum tailings and phosphogypsum slurry water (or tailings return water) from contacting the support sheet 11 and corroding the support sheet 11 .

[0057] The stress cycles experienced by a slurry pump impeller during use are primarily caused by rotational cyclical loads and vibrational loads. Rotational cyclical loads involve each impeller rotating once, with each part experiencing a complete stress cycle. Vibrational loads are high-frequency alternating stresses caused by water flow disturbances, mechanical resonance, or external excitation. However, the effects of rotational loads on the root 20 and tip 21 of blade 2 are as follows: the number of cycles at the root 20 and tip 21 is the same (once per revolution), but the stress amplitude increases from the root 20 to the tip 21. Conversely, the effects of vibrational loads on the root 20 and tip 21 of blade 2 are as follows: because the constraint effect on blade 2 decreases from the root 20 to the tip 21, the root 20 may experience more frequent stress fluctuations due to the constraint effect. In summary, the tip 21 of blade 2 experiences greater stress (e.g., centrifugal force), but the number of cycles is primarily driven by rotational speed, resulting in a lower frequency. The root 20 of blade 2 experiences less stress (e.g., centrifugal force), but the number of cycles is driven by both rotational speed and vibration, resulting in a higher frequency.

[0058] In traditional designs, the root 20 of the blade 2 suffers from rapid fatigue failure of the metal skeleton due to cyclic stress concentration. This application changes the stress distribution by placing the support sheet 11 close to the end 21 of the blade 2. The support sheet 11, which is made of metal with a high fatigue limit, supports the end 21, while the root 20 is supported by the fatigue-resistant material of the blade 2 itself, allowing the end 21 to withstand more centrifugal force. The root 20 shares the load with the support sheet 11 close to the end 21, reducing the local stress amplitude and subjecting the root 20 to less stress. The fatigue-resistant properties of the material of the blade 2 itself (such as ceramics, carbon fiber composite materials, etc.) allow the root 20 to resist fatigue damage during high-speed cyclic stress, thereby extending the overall life of the blade 2.

[0059] The squirrel-cage structure formed by the metal core 1 through the combination of the cover plate and the support plate 11 improves the overall rigidity of the impeller, especially suppressing the bending deformation of the blade 2 caused by centrifugal force under high-speed rotation; for blades 2 made of brittle materials (such as ceramics), the support of the metal core 1 can reduce the stress concentration at the end 21 of the blade 2, avoid brittle fracture, and allow the impeller diameter to be increased to meet high head requirements.

[0060] The blades 2 are designed in a circular array, and the support pieces 11 correspond one to one with the blades 2. The evenly distributed support pieces 11 ensure that each blade 2 is subjected to balanced force, reducing the risk of local overload and improving the stability of the impeller operation.

[0061] The anti-fatigue property refers to the comprehensive ability of a material to resist the initiation, propagation, and ultimate fracture of fatigue cracks under repeated cyclic loading. It reflects the overall tolerance of the material to fatigue damage and is usually quantified by the fatigue life (number of cycles) or the crack propagation rate.

[0062] The fatigue limit refers to the maximum alternating stress amplitude at which a material does not fracture under an infinite number of stress cycles. If a material has a high fatigue limit, it is said to have a high fatigue limit.

[0063] According to some embodiments of the present application, optionally, as Figure 4 shown, a plurality of through holes 13 are provided on both the support piece 11 and the first cover plate 10.

[0064] The sizes of the plurality of through holes 13 may be the same; alternatively, the sizes of the plurality of through holes 13 may be different.

[0065] When the sizes of the plurality of through holes 13 are different, the sizes of some of the through holes 13 near the connection between the support piece 11 and the first cover plate 10 may be smaller than those of the other through holes 13. The stress at the connection between the support piece 11 and the first cover plate 10 is relatively large, and the smaller sizes of the through holes 13 in this area can reduce the impact of the setting of the through holes 13 on the strength of the connection between the support piece 11 and the first cover plate 10, thereby reducing the risk of damage to the connection between the support piece 11 and the first cover plate 10.

[0066] A plurality of through holes 13 are provided on both the support piece 11 and the first cover plate 10. The through holes 13 can significantly reduce the weight of the support piece 11 and the cover plate, thereby reducing the overall mass of the metal core 1 and reducing the cyclic load on the root 20 of the blade 2 due to the centrifugal force during high-speed rotation. After the weight is reduced, the bending moment and inertial force borne by the root 20 of the blade 2 are reduced, further delaying the accumulation of fatigue damage at the root 20 and improving the service life of the slurry pump impeller provided by the present application. The through holes 13 provide mechanical anchoring points for the material of the blade 2 during the manufacturing process, and the slurry or binder penetrates into the holes to form a "locking structure", improving the interfacial bonding strength and reducing the risk of separation between the metal core 1 and the blade 2.

[0067] According to some embodiments of the present application, optionally, as Figure 8 shown, the dimension from one end of the support piece 11 near the root 20 to the end near the tip 21 is the length dimension of the support piece 11; the axes of the plurality of blades 2 pass through the center of the first cover plate 10; the center of one of the pair of first cover plates 10 is connected to the driving member, and the center of the other is provided with a liquid inlet; the length dimension of the support piece 11 on the side near the driving member is R1; the length dimension of the support piece 11 on the side near the liquid inlet is R2; and R1 > R2 is satisfied.

[0068] The first cover plate 10 directly connected to the driving member in the metal core 1 is strongly restricted by the driving member, while the other first cover plate 10 is at a certain distance from the driving member and is weakly controlled by the driving member. When R1 > R2, the length dimension of the end of the support piece 11 close to the driving member is greater than the dimension of the end of the support piece 11 close to the liquid inlet. The dimension of the end of the support piece 11 close to the liquid inlet is small, so that the weight of the part of the metal core 1 far from the driving member is small, and thus the inertia of this part is small, which can adapt to the weak control effect of the driving member, thereby preventing the part of the metal core 1 far from the driving member from vibrating relative to the driving member and affecting the normal rotation of the impeller. Moreover, after the material enters the impeller, it will continue to flow axially into the impeller under the action of the suction force of the negative pressure until it is blocked by the first cover plate 10 connected to the driving member and changes the flow direction. After the material contacts the first cover plate 10 connected to the driving member, it will continue to contact the blade 2, that is, the part of the impeller close to the driving member will share this part of the impact force. The length dimension of the end of the support piece 11 close to the driving member is large, which can provide a relatively reliable support effect for this part of the impeller and improve the service life of the impeller.

[0069] According to some embodiments of the present application, optionally, as Figure 8 shown, the end of the support piece 11 close to the end 21 is flush with the outer peripheral surface of the first cover plate 10.

[0070] The end of the support piece 11 close to the end 21 is flush with the outer peripheral surface of the first cover plate 10, so that the size of the space at the center of the plurality of support pieces 11 gradually decreases from the suction port to the driving member, and the shape of the support piece 11 is adapted to the shape of the impeller, so that the size of the opening at the center of the impeller gradually decreases from the suction port to the driving member. This setting makes the channel through which the material flows gradually narrow during the process of entering the impeller until it is blocked and redirected, allowing the water flow to concentrate and rush, reducing energy loss.

[0071] According to some embodiments of the present application, optionally, as Figures 1 to 2 shown, it further includes a pair of second cover plates 3; the pair of second cover plates 3 are arranged oppositely along the first direction X; the first cover plate 10 is located inside the second cover plate 3; the blade 2 is located between the pair of second cover plates 3, and the blade 2 is fixedly connected to the second cover plate 3.

[0072] The material of the second cover plate 3 can be the same as that of the blade 2; or, the material of the second cover plate 3 can be different from that of the blade 2.

[0073] On the one hand, as an outer protective cover, the second cover plate 3 wraps the first cover plate 10 inside, preventing the paste formed by the mixture of phosphogypsum tailings and phosphogypsum slurry water (or tailings return water) from directly scouring the metal first cover plate 10, and significantly reducing the risk of corrosion and damage to the first cover plate 10. On the other hand, the blade 2 is fixedly connected to the second cover plate 3, enabling part of the centrifugal force to be transmitted to the wheel shaft connected to the slurry pump blade through the second cover plate 3, reducing the stress amplitude at the root 20, and thus reducing the risk of damage to the root 20.

[0074] According to some embodiments of the present application, optionally, both ends of the support piece 11 extend into a pair of second cover plates 3 and are respectively connected to a pair of first cover plates 10.

[0075] Both ends of the support piece 11 are fixedly connected to the first cover plate 10 and the second cover plate 3 respectively, forming a rigid connection penetrating the inner and outer layers, integrating the metal core bone 1 and the second cover plate 3 into a three-dimensional support framework, enhancing the overall bending stiffness of the impeller, and suppressing the radial deformation of the blade 2 under high centrifugal force. The second cover plate 3 and the blade 2 wrap the entire metal core bone 1 inside, preventing the paste formed by the mixture of phosphogypsum tailings and phosphogypsum slurry water (or tailings return water) from contacting the metal core bone 1. The support piece 11 passes through the second cover plate 3 and is connected to the first cover plate 10, forming a physical anchoring point. Even if microcracks occur at the connection interface between the outer second cover plate 3 and the blade 2, the internal support piece 11 and the first cover plate 10 can still provide mechanical support, prevent crack propagation, and enhance the structural stability of the slurry pump impeller.

[0076] According to some embodiments of the present application, optionally, the material of the blade 2 is carbon fiber composite material.

[0077] The material of the blade 2 can be, but is not limited to, carbon fiber / epoxy resin composite material, carbon fiber / polyimide resin composite material, carbon fiber / phenolic resin composite material, etc.

[0078] Due to the large brittleness of traditional ceramic blades 2, the diameter of the impeller is limited, making it difficult to meet the high head requirements. The material of the blade 2 provided in the present application is carbon fiber composite material. The tensile strength of carbon fiber composite material (CFRP) is higher than that of steel, and it also has excellent impact toughness, can withstand greater centrifugal force, allows the diameter of the slurry pump impeller to be larger, and thus enhances the delivery head. The density of the carbon fiber composite material is relatively low, which can reduce the weight of the blade 2, reduce the load on the metal core bone 1 caused by centrifugal force, and thus reduce the stress amplitude at the root 20 and extend the fatigue life. The carbon fiber composite material also has extremely high corrosion resistance, which can effectively prevent the blade 2 from being corroded by phosphogypsum slurry water (or tailings return water).

[0079] According to some embodiments of the present application, optionally, as Figure 5As shown in the figure, the present application provides a manufacturing method for a slurry pump impeller, which is used to manufacture the above-mentioned slurry pump impeller. The manufacturing method of the slurry pump impeller includes: Step S100: Connect a first cover plate 10 to one end of a plurality of support pieces 11; Step S200: Install a disposable inner mold between the plurality of support pieces 11, and then connect another first cover plate 10 to the other end of the plurality of support pieces 11 to obtain a metal core frame 1; Step S300: Place the metal core frame 1 with the disposable inner mold into a molding die and perform injection molding to obtain the slurry pump impeller.

[0080] A disposable inner mold is a temporary support structure used to form an internal cavity during the injection of a molding liquid, and is used to produce components with complex shapes. The disposable inner mold may be made of degradable materials, foam plastics, gypsum, salts, etc., so as to facilitate its disposal after use.

[0081] The support pieces 11 can be welded to the first cover plate 10.

[0082] Injection molding, also known as injection moulding, is a molding method that combines injection and moulding. At a certain temperature, the fully molten material (i.e., the molding liquid) is stirred by a screw and injected into the mold cavity (the molding cavity of the molding die) under high pressure. After cooling and solidification, the molded part is obtained. This method is suitable for the mass production of components with complex shapes and is one of the important processing methods. The injection molding process can be roughly divided into six stages: mold closing, injection, holding pressure, cooling, mold opening, and product removal.

[0083] The molten molding liquid injected into the molding die has a certain temperature, that is, the injection temperature.

[0084] In step S100, one end of the multiple support sheets 11 is connected to one of a pair of first cover plates 10, and the positions of the multiple support sheets 11 are fixed. In step S200, a disposable inner mold is installed between the multiple support sheets 11 from the end of the support sheet 11 that is not connected to the cover plate, and then another first cover plate 10 is connected to the other end of the multiple support sheets 11 to obtain a metal core bone 1. The inner mold accurately fills the gap between the support sheets 11 to ensure that the non-metallic material (such as carbon fiber prepreg, corrosion-resistant engineering plastic) is evenly wrapped around the metal core bone 1 during injection molding to avoid stress concentration caused by eccentricity or uneven wall thickness. Finally, in step S300, the metal core bone 1 equipped with the disposable inner mold is placed into the molding mold and injection molded to obtain the slurry pump impeller. The other first cover plate 10 is connected to the support sheet 11 only after the disposable inner mold is installed between the support sheets 11, which simplifies the installation process of the disposable inner mold and makes it easier for the operator to adjust and determine the position of the disposable inner mold, reducing the risk of eccentricity or uneven wall thickness of the metal core 1. A disposable inner mold is used to complete the molding of the entire inner cavity of the slurry pump impeller, so that the wall of the inner cavity of the manufactured slurry pump impeller is flat and smooth, avoiding burrs and unevenness that may occur in the inner cavity manufactured by piecing together multiple inner molds. The manufacturing method of the slurry pump impeller provided in this application realizes the precision molding of high-lift, large-sized impellers by prefabricating the metal core 1 + auxiliary injection molding of the inner mold, providing a manufacturing solution for slurry pump impellers with high efficiency, high reliability and low environmental load.

[0085] According to some embodiments of the present application, optionally, Figures 6 to 7 As shown, step S400 is further included between step S200 and step S300: a transition layer 4 is provided on the molding surface 12 of the metal core 1; wherein the molding surface 12 is the surface of the metal core 1 in contact with the molding liquid through the transition layer 4; the transition layer 4 is composed of M layers of transition material, M≥3; the innermost N layers of transition material are the first material 40, the first material 40 has elasticity, M>N≥1, and the first material 40 is in close contact with the molding surface 12; the outermost K layer of transition material is the second material 41, the second material 41 has adhesion, M>K≥1; the L layer of transition material located between the first material 40 and the second material 41 is the third material 42, the third material 42 has low thermal conductivity, M>L≥1, N+K+L≤M.

[0086] The molten molding liquid injected into the molding mold has a certain temperature, namely the injection temperature.

[0087] The forming temperature range of carbon fiber composite materials varies depending on their matrix materials (resins or high-temperature matrices) and processes. The temperature range for carbon fiber casting spans a wide range. For example: medium- and low-temperature resin-based carbon fibers (120°C to 230°C), high-temperature thermoplastic carbon fibers (300°C to 400°C), ultra-high-temperature carbon / carbon composite materials (>800°C). During the actual processing, suitable transition layer 4 materials can be selected according to the actual processing temperature.

[0088] When injecting the forming liquid, since the third material 42 has a low thermal conductivity, the amount of heat absorbed by the metal core 1 from the forming liquid and the subsequent thermal expansion of the metal core 1 itself are reduced. The first material 40 deforms as the metal core 1 expands. During the cooling stage of the forming liquid, the metal core 1 contracts in volume due to its own temperature reduction. The transition layer 4 adheres to the forming surface 12 of the metal core 1 and maintains close contact. The first material 40 deforms synchronously with the contraction of the metal core 1. At the same time, the second material 41 has high fluidity and self-sealing properties. The second material 41 can fill the gap between the formed body formed after the cooling of the forming liquid and the third material 42, enabling the transition layer 4 to fill the voids vacated after the contraction of the metal core 1 and the voids that appear after the cooling and hardening of the forming liquid, reducing the probability of defects such as cavities or holes between the forming liquid and the metal core 1 during the cooling and hardening stage of the forming liquid.

[0089] According to some embodiments of the present application, optionally, the first material 40 is silicone rubber.

[0090] The temperature resistance range of silicone rubber (-60°C to 250°C) covers the requirements of most injection molding processes. During high-temperature injection molding, silicone rubber does not undergo thermal decomposition or permanent deformation, ensuring the integrity of the elastic layer.

[0091] The first material 40 is silicone rubber, which has the characteristics of low elastic modulus and excellent flexibility. It can stably adhere to the metal core 1 and can compensate for the amount of thermal expansion of the metal core 1 during the injection molding process through its own elastic deformation, thereby avoiding the occurrence of cavities between the metal core 1 and the blade 2 and the second cover plate 3 due to the thermal expansion and contraction of the metal core 1, and improving the overall density of the slurry pump impeller.

[0092] According to some embodiments of the present application, optionally, the second material 41 is an epoxy resin-based nanocomposite.

[0093] The epoxy resin-based nanocomposite is an epoxy resin added with nanoparticles (such as carbon nanotubes, graphene) and has good fluidity.

[0094] The second material 41 is an epoxy resin-based nanocomposite. The epoxy resin-based nanocomposite can infiltrate the surfaces of the blade 2 and the second cover plate 3 facing the metal core 1, and form a dense structure after curing. Its high adhesion can enhance the interfacial bonding force between the metal core 1 and the blade 2 and the second cover plate 3, reduce the defects on the surfaces of the blade 2 and the second cover plate 3 facing the metal core 1, improve the connection stability between the metal core 1 and the blade 2 and the second cover plate 3, and also improve the compactness inside the impeller of the slurry pump.

[0095] According to some embodiments of the present application, optionally, the third material 42 is a ceramic-based coating.

[0096] The ceramic-based coating can be, but is not limited to, alumina, boron nitride, etc.

[0097] The third material 42 is a ceramic-based coating. The ceramic-based coating has a low thermal conductivity (<30 W / m·K) and high-temperature stability (>1000 °C), and can effectively block the heat conduction of the molding liquid to the metal core 1, reduce its thermal expansion amplitude, and prevent the expansion amount of the metal core 1 from exceeding the compensable amount of the first material 40, thereby reducing the risk of cavities appearing between the metal core 1 and the blade 2 and the second cover plate 3.

[0098] Although the present application has been described with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A slurry pump impeller, characterized in that, Comprising: A metal core framework, including a pair of first cover plates and a plurality of support sheets; The pair of first cover plates are arranged oppositely along a first direction; The support sheets are located between the pair of first cover plates, and the support sheets are fixedly connected to the cover plates; A plurality of blades, the blades being provided with roots and ends along their length directions; Wherein, the plurality of blades are circumferentially arrayed with the first direction as the axis; The roots are closer to the axis of the plurality of blades than the ends; The support sheets pass through the blades, and the support sheets support the blades; The support sheets are configured to be closer to the ends among the ends and the roots; The plurality of blades correspond one-to-one with the plurality of support sheets.

2. The slurry pump impeller according to claim 1, characterized in that, A plurality of through holes are provided on both the support sheets and the first cover plates.

3. The slurry pump impeller according to claim 1, characterized in that, The dimension from the end of the support sheet close to the root to the end close to the end is the length dimension of the support sheet; The axes of the plurality of blades pass through the centers of the first cover plates; The center of one of the pair of first cover plates is connected to a driving member, and a liquid inlet is provided at the center of the other; The length dimension of the side of the support sheet close to the driving member is R1; The length dimension of the side of the support sheet close to the liquid inlet is R2; Satisfying, R1 > R2.

4. The slurry pump impeller according to claim 3, wherein, The end of the support sheet close to the end is flush with the outer peripheral surface of the first cover plate.

5. The slurry pump impeller according to claim 1, wherein, It further includes a pair of second cover plates; The pair of second cover plates are arranged oppositely along the first direction; The first cover plates are located inside the second cover plates; The blades are located between the pair of second cover plates, and the blades are fixedly connected to the second cover plates.

6. The slurry pump impeller according to claim 5, characterized in that, Both ends of the support sheets extend into the pair of second cover plates and are respectively connected to the pair of first cover plates.

7. A slurry pump impeller according to claim 1, characterized in that, The material of the blades is carbon fiber composite material.

8. A manufacturing method of a slurry pump impeller for manufacturing the slurry pump impeller according to any one of claims 1 to 7, characterized in that, Including: Step S100: Connect one of the first cover plates to one end of the plurality of support sheets; Step S200: Install a disposable inner mold between the plurality of support sheets, and then connect the other first cover plate to the other ends of the plurality of support sheets to obtain the metal core framework; Step S300: Place the metal core framework with the disposable inner mold into a molding mold and perform injection molding to obtain a slurry pump impeller.

9. The manufacturing method of a slurry pump impeller according to claim 8, characterized in that, There is also a step S400 between step S200 and step S300: Set a transition layer on the molding surface of the metal core framework; Wherein, the molding surface is the surface of the metal core framework that contacts the molding liquid through the transition layer; The transition layer is composed of M layers of transition materials, M ≥ 3; The innermost N layers of the transition materials are the first materials, the first materials have elasticity, M > N ≥ 1, and the first materials are in close contact with the molding surface; The outermost K layers of the transition materials are the second materials, the second materials have adhesiveness, M > K ≥ 1; The L layers of the transition materials located between the first materials and the second materials are the third materials, the third materials have low thermal conductivity, M > L ≥ 1, N + K + L ≤ M.

10. The manufacturing method of a slurry pump impeller according to claim 9, characterized in that, The first material is silicone rubber.

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