A large silicon carbide ceramic impeller

Abstract

The present invention discloses a large silicon carbide ceramic impeller, which is composed of several parts including a plurality of ceramic impeller bodies; the plurality of ceramic impeller bodies are arranged in a circle, and each ceramic impeller body includes a front plate, a rear plate, a first blade plate and a second blade plate sintered into one body, wherein the front plate, the rear plate, the first blade plate and the second blade plate surround to form a channel; the two ends of the channel are respectively connected to the suction port and the outlet of the ceramic impeller body; the first blade plate in the ceramic impeller body and the second blade plate in another ceramic impeller body adjacent thereto are combined to form a blade, and a first cavity is provided in the middle of the blade, and the first cavity extends along the working surface of the blade toward the outlet direction of the ceramic impeller body. Through the above improvements, the reliability of the large silicon carbide ceramic impeller of the present invention is higher.

Description

Technical Field

[0001] The invention belongs to the technical field of functional ceramic materials, and more specifically, relates to a large silicon carbide ceramic impeller. Background Art

[0002] The impeller of a slurry pump is the most severely worn component of a slurry pump, and is generally made of wear-resistant alloy or wear-resistant rubber. However, in some working conditions with severe wear, wear-resistant alloy impellers and wear-resistant rubber impellers often cannot meet the use requirements. In order to increase the life of the impeller, silicon carbide ceramic materials with good wear resistance are currently being tried to be used to make the impeller. Depending on the process and raw materials, common silicon carbide ceramics mainly include pressureless sintered silicon carbide, hot-pressed sintered silicon carbide, reaction-sintered silicon carbide, silicon nitride combined with silicon carbide, and oxide combined with silicon carbide. Among them, pressureless sintered silicon carbide and hot-pressed sintered silicon carbide can only manufacture some simple-shaped workpieces due to the complex molding and sintering processes, and cannot manufacture complex large parts such as slurry pump impellers; the latter three can be formed by casting or grouting processes, so they can manufacture workpieces with complex shapes. At present, almost all silicon carbide ceramic impellers are made of the latter three materials.

[0003] Silicon nitride bonded with silicon carbide and oxide bonded with silicon carbide can be cast, which is easy to manufacture workpieces with complex shapes such as impellers. The basic production process of silicon nitride bonded with silicon carbide and oxide bonded with silicon carbide is: mix α-SiC particles with metal silicon powder, binder, water, etc. evenly, inject into the mold for molding, demold and dry; heat the blank to 1420℃ under high-purity nitrogen, then the metal silicon powder and nitrogen in the blank react to form silicon nitride, and finally obtain silicon nitride bonded with silicon carbide; place the blank in oxygen or air and heat to 1420℃, then the metal silicon powder and oxygen in the blank react to form silicon oxide, and finally obtain oxide bonded with silicon carbide. The porosity of silicon nitride bonded with silicon carbide is generally 8%-15%, and the α-Si C content is generally 65%-80%. The flexural strength is generally 30-60Mpa. The porosity of oxide bonded with silicon carbide is generally 15%-20%, and the α-Si C content is generally 75%-85%. The flexural strength is generally 20-30Mpa.

[0004] Reaction-bonded silicon carbide ceramics generally refer to reaction-bonded silicon carbide. There is also reaction-formed silicon carbide, sometimes also called reaction-bonded silicon carbide, that is, the material is all β-SiC generated by carburization reaction, but this material has poor processability and high cost, and there is no report of its commercial application in manufacturing impellers. When manufacturing workpieces with complex shapes such as impellers, they are all reactively bonded silicon carbide, and grouting molding is generally used. The manufacturing process is: raw materials containing α-SiC micropowder and carbon black micropowder are added with water, a binder, a dispersant, etc., and mixed evenly to form a slurry, which is then injected into the cavity of a gypsum mold (or other water-absorbing mold). The gypsum mold absorbs the water in the slurry. After the slurry loses some of its water, the binder gives the blank a certain strength. The gypsum mold is removed to obtain the blank. After the ceramic blank is dried, the blank and excess metallic silicon particles are stacked in a reactive sintering furnace, and the temperature is raised to about 800°C in a vacuum or inert gas. The binder and the dispersant are completely carbonized. The temperature is further raised to 1500-1700°C, and the metallic silicon is liquefied or vaporized. Under the action of capillaries, it penetrates into the blank and reacts with the carbon in the blank to form β-SiC, and the α-SiC in the blank is formed. C powder is combined together, and the excess metallic silicon fills the pores in the blank at the same time. After cooling, a ceramic material with very low porosity (generally less than 0.1%) is obtained, and the main components are silicon carbide (generally α-SiC+β-SiC content is 85-93%) and free silicon (also called residual silicon, generally 7-15%). Reaction-sintered silicon carbide not only has much higher wear resistance than silicon nitride combined with silicon carbide and oxide combined with silicon carbide, but also has much higher mechanical strength than the latter two. Generally, the bending strength can reach 250-500Mpa. Therefore, the impeller made of reaction-sintered silicon carbide ceramic impeller material should be significantly better than that of silicon nitride combined with silicon carbide and oxide combined with silicon carbide in terms of wear resistance and strength. However, the actual situation is not the case. The impeller using the latter two materials can currently achieve a diameter of about 1700mm, and its reliability can meet the use requirements. The reaction-sintered silicon carbide impeller manufactured by conventional technology can only achieve a diameter of about 500mm; for example, China's authorized utility model patent (authorization announcement number is CN209687784U) discloses "an integral ceramic impeller". At present, some models of reaction-sintered silicon carbide ceramic impellers manufactured according to this technical solution have been put into commercial use. However, the current successful market use is limited to some small models and their diameters generally do not exceed 500mm. When manufacturing reaction-sintered silicon carbide impellers with larger diameters, it is found that the yield rate is very low, which leads to a sharp increase in costs, and the manufactured impellers have poor impact resistance. Not only are they prone to rupture when used under strong impact conditions, but the probability of rupture is also high under slight impact conditions.

[0005] In order to solve the problem that the impeller is difficult to enlarge, the Chinese authorized utility model patent (authorization announcement number is CN209687784U) also discloses another ceramic impeller. The invention concept of this ceramic impeller is to split the large ceramic impeller into several easy-to-manufacture parts for separate manufacturing, and then splice these parts into one. In practice, it is found that when this technical solution is used to manufacture large impellers, if the ceramic material is silicon nitride combined with silicon carbide or oxide combined with silicon carbide, under the current process technology conditions, larger impellers can indeed be manufactured; the maximum impeller diameter can currently be about 1700mm; but if the ceramic material is reaction-sintered silicon carbide, when the impeller is enlarged, especially when the impeller diameter exceeds 700mm, there are still problems that the impeller is easy to break and the yield is low, and the mechanical strength and reliability of the impeller are much lower than those of silicon nitride combined with silicon carbide impellers or oxide combined with silicon carbide impellers.

[0006] In view of the above problems, technicians naturally thought of increasing the thickness of impeller-related parts to improve the strength of the impeller. For example, the

[0063] paragraph in the Chinese authorized utility model patent (authorization announcement number CN209687784U) points out that increasing the thickness of the blades can improve the strength of the impeller. This is also consistent with the experience of ordinary technicians. Therefore, in the design, the thickness of the front cover plate, rear cover plate or blade of a large ceramic impeller is often designed to reach 70-120mm. Our further research found that this experience should be correct for other ceramics, such as silicon nitride combined with silicon carbide, oxide combined with silicon carbide, alumina ceramics, etc., and the expected effect can be obtained after thickening; but for reaction-sintered silicon carbide, this is not entirely true. In many cases, the reliability of the impeller after thickening has not been improved, and even many contrary cases have occurred. Through further calculations, it can be found that the theoretical strength of these reaction-sintered silicon carbide impellers that are broken during use is not only much greater than that of silicon nitride combined with silicon carbide or oxide combined with silicon carbide, but also the strength safety factor is much greater than the actual requirements of the impeller.

[0007] Through in-depth research on this phenomenon, it was found that for silicon nitride bonded silicon carbide ceramics and oxide bonded silicon carbide ceramics, due to the high porosity, these tiny pores can greatly reduce the internal stress generated during the ceramic sintering process and absorb the stress caused by external impact. Therefore, the residual stress of the workpiece is small. After the front cover plate, rear cover plate and blades of the impeller are thickened, the mechanical strength of the impeller can also be improved accordingly.

[0008] Through research, it is also found that: since reaction sintered silicon carbide is currently formed by grouting with a plaster mold or other water-absorbing mold, the surface of the workpiece is in contact with the mold during grouting, and the water in the slurry is quickly absorbed. However, the water content of the part far from the mold inside the workpiece is significantly higher than that of the workpiece surface at the end of molding due to the relatively weak capillary action of the mold, which makes the density of the surface of the blank after drying significantly higher than that of the inside of the blank. After the carbonization reaction is completed during sintering, the excess metal silicon liquid will fill the gaps between the silicon carbides, so that the free silicon content of the part with higher density of the blank after sintering will be lower than that of the part with lower density of the blank, that is, the free silicon content of the workpiece surface will be lower than that of the inside of the workpiece. According to the normal process of the prior art, the free silicon content of the surface can be controlled at 8-12%, and the further away from the surface, the higher the free silicon content, and the free silicon content of the core can reach 15-18%. Free silicon not only reduces wear resistance and bending strength, but more importantly, it increases the brittleness of the ceramic and reduces impact resistance. Therefore, in production, efforts are generally made to increase the density of the blank to reduce the free silicon content of the product. However, in production practice, improving the density of the blank is restricted by various factors, and the existing gypsum mold grouting molding technology is difficult to significantly improve the density and consistency of the blank. Therefore, for impellers with smaller diameters, such as impellers with a diameter of 500mm, the thickness of the blades and cover plates generally does not exceed 50mm. At this time, appropriately increasing the thickness of the blades or cover plates has a relatively small effect on the density of the impeller blank, which is an important reason for the relatively high reliability of small reaction-sintered silicon carbide impellers. However, for large impellers, for strength and wear resistance considerations, the thickness of the blades and cover plates is often designed to be 80-120mm. At this time, the density of the cast impeller blank is quite different, which will lead to large differences in the microstructure of the ceramic organization after sintering. In some cases, the so-called silicon core even appears, and the free silicon content in the center is close to 100%, which will cause the workpiece to produce large residual stress when cooling after sintering; the greater the thickness of the workpiece and the larger the outer dimensions, the greater the residual stress. Unlike silicon nitride bonded silicon carbide or oxide bonded silicon carbide ceramics which have a large number of pores, the porosity of reaction-sintered silicon carbide ceramics is close to zero, so the stress generated by sintering cannot be eliminated through the pores. Therefore, for thicker workpieces, under the same external dimensions, the residual stress of reaction-sintered silicon carbide workpieces is much greater than that of silicon nitride bonded silicon carbide and oxide bonded silicon carbide. On the one hand, the larger residual stress causes the workpiece to break or produce hidden cracks during the sintering process, which reduces the yield of the product. On the other hand, it causes the workpiece to have a larger residual stress, which is easy to break from the part with greater stress when subjected to external force or impact. Therefore, for reaction-sintered silicon carbide impellers, increasing the thickness of the blades or cover plates does not necessarily increase the strength and impact resistance of the impeller, and sometimes it may even be counterproductive.

[0009] Therefore, through the above research, it is found that the main or important reason why the existing technology cannot achieve large-scale and high reliability of reaction-sintered silicon carbide ceramic impellers is precisely the key to solving the problem. Summary of the invention

[0010] In order to solve the deficiencies and shortcomings of the prior art, an object of the present invention is to provide a large silicon carbide ceramic impeller.

[0011] The technical solution of the present invention for solving the problems of the prior art is:

[0012] A large silicon carbide ceramic impeller is formed by splicing together several components including a plurality of ceramic impeller bodies made of reaction-sintered silicon carbide material; the plurality of ceramic impeller bodies are arranged circumferentially, and each ceramic impeller body comprises a front plate, a rear plate, a first blade plate and a second blade plate sintered into one body, wherein the front plate, the rear plate, the first blade plate and the second blade plate are surrounded to form a channel; the two ends of the channel are respectively connected to the suction port and the outlet of the ceramic impeller body; the first blade plate in the ceramic impeller body and the second blade plate in another adjacent ceramic impeller body are spliced ​​to form a blade, and a first cavity is provided in the middle of the blade, and the first cavity extends along the working surface of the blade toward the outlet direction of the ceramic impeller body.

[0013] Preferably, the extension length of the first cavity along the working surface of the blade toward the outlet direction of the ceramic impeller body is 30%-80% of the length of the blade; according to the size of the impeller and the shape of the blade, the length of the first cavity is set to 30%-80% of the length of the blade, which can eliminate or greatly reduce the probability of producing thicker parts in the blade, so that the density difference of the obtained blank is smaller and the residual stress after sintering is smaller; after setting one or two cavities, although the theoretical mechanical strength of the ceramic impeller body will decrease, the theoretical mechanical strength calculation cannot take into account the influence of residual stress, and the first cavity is reinforced by the filled adhesive. Therefore, the actual reliability of the ceramic impeller body of the present invention will be significantly improved compared with the scheme without setting the first cavity, and its impact resistance is also significantly improved.

[0014] Preferably, the splicing line between two adjacent ceramic impeller bodies includes a first splicing line and a second splicing line, wherein the first splicing line passes through the tail of the first cavity and the tail of the blade; the second splicing line passes through the head of the first cavity and the working surface or back surface of the blade, and the distance between the second splicing line from the working surface or back surface of the impeller to the head of the blade is 1-2 times the average thickness of the blade.

[0015] Since the first joint line passes through the tail of the first cavity and the tail of the blade, the length of the joint line between two adjacent ceramic impeller bodies that is washed can be minimized, which is beneficial to reducing the wear of the impeller. In addition, since the blade head is the part of the entire impeller that is most severely impacted and worn, if the second joint line of the adjacent ceramic impeller body passes through the head of the first cavity and the back or working surface of the blade, it can be avoided that the joint line passes through the blade head, thereby improving the life of the impeller. If the distance between the second splicing line set on the back side or working surface of the blade and the blade head is small, after the blade head is worn to the second splicing line, rapid wear will occur due to the second splicing line and the first cavity, shortening the life of the impeller; on the contrary, if the distance between the second splicing line set on the back side or working surface of the blade and the blade head is large, a thicker and longer part will be formed on the blade head, resulting in a large difference in the density of the resulting blank and a large residual stress after sintering, thereby reducing the impact resistance of the impeller; according to the shape or size of the blade, when the distance from the second splicing line on the back side or working surface of the blade to the blade head is set to 1-2 times the average thickness of the blade, the above contradiction can be better balanced.

[0016] Preferably, the first blade plate of the ceramic impeller body is provided with a protrusion at its head position, and the head of the second blade plate of another ceramic impeller body adjacent to the ceramic impeller body after splicing is arranged at the rear end of the protrusion; or, the second blade plate of the ceramic impeller body is provided with a protrusion at its head position, and the head of the first blade plate of another ceramic impeller body adjacent to the ceramic impeller body after splicing is arranged at the rear end of the protrusion. Through the above arrangement, the protrusion at the head position of the first blade plate can protect the head of the second blade plate, preventing the head of the second blade plate at the splicing line from being quickly worn, and vice versa.

[0017] Preferably, a second cavity is provided on the front plate, and the depth of the second cavity is 25%-75% of the thickness of the front cover plate; a front lining plate is installed in the second cavity; a second frame is also provided in the second cavity, and the second frame is provided at the lower end of the front lining plate; the front cover plate includes a front plate, a front lining plate and a second frame.

[0018] Since the front cover of large impellers is relatively thick, often reaching 60mm-100mm, for large impellers with thicker front cover, if the second cavity is not set, the thickness of the front cover will be significantly higher than the blade or rear cover, resulting in a large difference in the density of the blank after grouting, and a large residual stress will be generated after sintering, increasing the probability of hidden cracks or ruptures in the ceramic impeller body and reducing the impact resistance of the impeller. After setting one or two cavities, the thickness of the ceramic impeller body on the front cover can be reduced, thereby reducing the residual stress of the ceramic impeller body. Since the bending strength of reaction-sintered silicon carbide ceramic material is very high, the theoretical strength of large impellers designed according to the prior art is much higher than the actual needs, but in actual use, the main reason for the low reliability of large ceramic impellers is that it is difficult to consider the influence of residual stress in theoretical calculations, and this factor has a great impact on the results. After the front liner and the ceramic impeller body are bonded, on the one hand, the residual stress in the front cover plate is significantly reduced due to the reduction in thickness. On the other hand, the probability of the hidden cracks in the front cover plate of the ceramic impeller body overlapping with the hidden cracks and stress concentration parts on the front liner is very low, thereby blocking the transmission of residual stress, and the influence of residual stress on the impeller strength is much smaller. Therefore, after the front liner and the second cavity are set, although the theoretical strength of the front cover plate is not improved, and may even be reduced, its actual strength and impact resistance are significantly improved. In addition, another function of setting the front liner is to cover the joint line between the ceramic impeller bodies to prevent the adhesive in the joint line from being quickly worn and causing damage to the impeller.

[0019] Preferably, the ceramic impeller body is provided with a sealing cone surface at the position of its suction port, and the distance from the inner edge of the second cavity to the outer edge of the sealing cone surface is 5mm-60mm. The cavitation resistance of the impeller can be improved by providing a sealing cone surface at the suction port of the impeller. The cone angle of the sealing cone surface is generally 10°-30°. If the second cavity is not provided, the front liner and the ceramic impeller body will be spliced ​​on the sealing cone surface, so that the front liner will be a sharp angle at the splicing line position, which greatly reduces its wear resistance and impact resistance. If the distance between the inner edge of the second cavity and the outer edge of the sealing cone surface is set to 5mm-60mm, the above-mentioned sharp angle splicing problem can be prevented, and at the same time, the excessive thickness of the ceramic impeller body at the sealing cone surface portion can be avoided to form a large residual stress.

[0020] Preferably, a first skeleton is disposed in the first cavity.

[0021] Preferably, a third cavity is provided on the rear plate, and a third frame is installed in the third cavity; the first frame and the third frame are connected.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The large silicon carbide ceramic impeller of the present invention is formed by splicing a plurality of ceramic impeller bodies, so that the outer dimensions of the ceramic impeller body are significantly smaller than the dimensions of the silicon carbide ceramic impeller, which is conducive to the large-scale large silicon carbide ceramic impeller of the present invention, can improve the yield rate and reduce the manufacturing cost.

[0024] 2. The ceramic impeller body in the large silicon carbide ceramic impeller of the present invention is a reaction sintered ceramic body composed of a front plate, a rear plate, a blade working surface, a blade back surface and other parts. The thickness of each part can be greatly reduced, so that the distance difference between each part of the blank and the surface of the gypsum mold during grouting molding is smaller, and the density difference of the obtained blank is smaller, so that the residual silicon content of each part after sintering is smaller, and the residual stress is smaller, especially in the blade part, the effect is more obvious, so that the impact resistance of the ceramic impeller body is significantly improved.

[0025] 3. The front plate, rear plate, first blade plate and second blade plate of the ceramic impeller body in the large silicon carbide ceramic impeller of the present invention together form a closed channel on the outside of a cross-section, so that each ceramic impeller body corresponds to a flow channel. Since there is almost no joint seam on the surface of the flow channel, this can not only reduce the efficiency loss caused by the misalignment of the joints, but also help to increase the life of the impeller.

[0026] 4. The blades of the ceramic impeller body in the present invention are composed of a working panel (i.e., the first blade plate) and a back panel (i.e., the second blade plate), wherein the thickness of the working panel and the back panel can be significantly smaller than the thickness of the blades, which is conducive to preventing the appearance of thicker parts, so that during grouting molding, the distance difference between each part of the blank and the surface of the gypsum mold is smaller, so that the density difference of the obtained blank is smaller, the residual silicon content of each part after sintering is smaller, and the residual stress is smaller. After the first cavity is formed by splicing in the middle of the blade, the thickness of the relevant part can be further reduced as needed.

[0027] 5. The working surface of the blades of the ceramic impeller body of the present invention and the back surface of the blades of another adjacent ceramic impeller body are spliced ​​together to form a first cavity. In this way, the thickness of the working surface and the back surface of the blades can be controlled within a suitable range by controlling the shape of the first cavity to reduce the residual stress after sintering. At the same time, the splicing part in the first cavity is not in contact with the fluid and is not subject to erosion and wear, so the adhesive at the splicing part is not easily worn and ineffective. After the first cavity is set, although the theoretical mechanical strength of the ceramic impeller body will decrease, the theoretical mechanical strength calculation cannot take into account the influence of residual stress, and the first cavity is reinforced by the filled adhesive. Therefore, the actual reliability of the ceramic impeller body of the present invention will be significantly improved compared with the solution without the first cavity, and its impact resistance is also significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a cross-sectional view of a large silicon carbide ceramic impeller of the present invention in Example 1.

[0029] Figure 2 for Figure 1 Section view at AA.

[0030] Figure 3 This is a cross-sectional view of the ceramic impeller body after assembly in Example 1.

[0031] Figure 4 This is a front view of the ceramic impeller body in Example 1 after being assembled.

[0032] Figure 5 This is a three-dimensional view of the ceramic impeller body in Example 1.

[0033] Figure 6 This is a cross-sectional view of the ceramic impeller body in Example 1.

[0034] Figure 7 for Figure 6 Cross-sectional view at BB.

[0035] Figure 8 This is a cross-sectional view of two ceramic impeller bodies assembled together in Example 1.

[0036] Fig. 9 This is a cross-sectional view of the rear lining plate in Example 1.

[0037] Fig.10 This is a cross-sectional view of a large silicon carbide ceramic impeller of the present invention in Example 2.

[0038] Fig.11 for Fig.10 Sectional view of CC.

[0039] Fig.12 It is a cross-sectional view of the ceramic impeller body in Example 2 at the center plane of the flow channel outlet after being assembled.

[0040] Fig.13 This is a cross-sectional view of the ceramic impeller body in Example 2.

[0041] Fig.14 for Fig.13 Sectional view at DD.

[0042] Fig.15 This is a cross-sectional view of the two ceramic impeller bodies in Example 2 assembled together.

[0043] In the figure: 1-ceramic impeller body, 011-first blade plate, 012-second blade plate, 013-front plate, 014-rear plate, 015-channel, 016-protrusion, 2-first skeleton, 3-hub, 4-third skeleton, 5-rear lining, 6-front lining, 7-joining line, 7A-first joint line, 7B-second joint line, 8-second cavity, 9-second skeleton, 10-sealing cone, 11-third cavity, 12-first cavity. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0045] Example 1

[0046] like Figure 1-Figure 8 As shown, the diameter of the large silicon carbide ceramic impeller of the present invention is 1435 mm, and it includes five ceramic impeller bodies 1. The ceramic impeller body 1 is made of reaction-sintered silicon carbide material. The ceramic impeller body 1 includes a front plate 013, a rear plate 014, a first blade plate 011 and a second blade plate 012 sintered into one piece; the front plate 013, the rear plate 014, the first blade plate 011 and the second blade plate 012 of the ceramic impeller body 1 surround a channel 015, and the two ends of the channel 015 are respectively connected to the suction port and the outlet of the ceramic impeller body 1.

[0047] The “front cover plate” described in this embodiment is a general term for the front side plate of the silicon carbide ceramic impeller of the present invention, including the front plate 013 and the front lining plate 6; correspondingly, the “rear cover plate” described in this embodiment is a general term for the rear side plate of the silicon carbide ceramic impeller of the present invention, including the rear plate 014 and the rear lining plate 5.

[0048] like Figure 1-Figure 8 As shown, the first blade plate 011 of the ceramic impeller body 1 and the second blade plate 012 of another adjacent ceramic impeller body 1 are assembled to form a blade, and a first cavity 12 is formed at the middle of the blade. An adhesive is arranged in the first cavity 12. In this embodiment, the adhesive is epoxy resin 6101. In order to improve the wear resistance, 50-80% silicon carbide powder needs to be added to the epoxy resin.

[0049] like Figure 1-Figure 8 As shown, the first cavity 12 extends along the working surface of the blade toward the impeller outlet;

[0050] Figure 2 and Figure 8It is a cross-sectional view of the ceramic impeller body 1 or the ceramic impeller body 1 after being assembled at the outlet center plane (i.e., the distance from this plane to the front cover plate and the rear cover plate at the impeller outlet is equal), wherein the length L1 of the first cavity 12 extending along the working surface of the blade toward the outlet direction is 468 mm, and the blade length L2 is 742 mm, i.e., the length of L1 is 63% of L2.

[0051] like Figure 1-Figure 8 As shown, the second joint line 7B of the adjacent ceramic impeller body 1 passes through the head of the first cavity 12 and the back of the blade, wherein the distance L3 from the second joint line 7B on the back of the blade to the blade head is 159 mm, which is 1.34 times the average thickness of the blade.

[0052] like Figure 1-Figure 8 As shown, the first blade plate 011 of a ceramic impeller body 1 is provided with a protrusion 016 at the head, and the head of the second blade plate 012 of another adjacent ceramic impeller body 1 is arranged at the rear end of the protrusion 016 after assembly.

[0053] like Figure 1-Figure 8 As shown, the first joint line 7A of the adjacent ceramic impeller bodies 1 passes through the tail of the first cavity 15 and the tail of the blade.

[0054] like Figure 1-Figure 8 As shown, after the ceramic impeller body 1 is assembled, a second cavity 8 is provided on the outer side of the front plate 013, and a front lining plate 6 and an adhesive are provided in the second cavity 8.

[0055] like Figure 3 As shown, the depth h of the second cavity 8 is 15 mm, and the total thickness H of the front cover is 60 mm, that is, the depth h of the first cavity 12 is 25% of the total thickness H of the front cover.

[0056] like Figure 1-Figure 8 As shown, after the ceramic impeller body 1 is assembled, a sealing cone surface 10 is formed at its suction port, and the distance B from the inner edge of the second cavity 8 to the outer edge of the sealing cone surface 10 is 5 mm.

[0057] like Figure 1 As shown, a first skeleton 2 made of carbon steel is disposed in the first cavity 12; a third cavity 11 is disposed on the rear plate 014, and a third skeleton 4 and an adhesive are disposed in the third cavity 11; the first skeleton 2 and the third skeleton 4 are welded into a whole.

[0058] Example 2

[0059] like Figure 10-Figure 15 As shown, the large silicon carbide ceramic impeller of the present invention is different from that of Example 1 in that:

[0060] A second frame 9 made of carbon steel is arranged in the second cavity 8;

[0061] The depth h of the second cavity 8 is 15 mm, and the total thickness of the front cover is 60 mm, that is, the depth of the first cavity 12 is 75% of the thickness of the front cover.

[0062] The extension length L1 of the first cavity 12 along the outlet direction of the ceramic impeller body 1 is 596 mm, and the blade length L2 is 746 mm, that is, the length of the first cavity 12 is 80% of the blade length.

[0063] like Figure 10-Figure 15 As shown, the second joint line 7B of the adjacent ceramic impeller body 1 passes through the head of the first cavity 12 and the working surface of the blade; the distance L3 from the second joint line 7B at the working surface of the blade to the blade head is 119 mm, which is 1 times the average thickness of the blade (i.e. 119 mm).

[0064] like Figure 10-Figure 15 As shown, the second blade plate 012 of the ceramic impeller body 1 is provided with a protrusion 016 at the head, and the head of the first blade plate 011 of another adjacent ceramic impeller body 1 is arranged at the rear end of the protrusion 016 after splicing.

[0065] like Fig.10 , Fig.12 As shown, after the ceramic impeller body 1 is assembled, a sealing cone surface 10 is formed at its suction port, and a distance B from the inner edge of the second cavity 8 to the outer edge of the sealing cone surface 10 is 60 mm.

[0066] The adhesive is made of vinyl resin.

[0067] The remaining structures are implemented with reference to Example 1.

[0068] Example 3

[0069] This embodiment is substantially the same as Embodiment 1, and the main differences are:

[0070] A second frame 9 made of carbon steel is arranged in the second cavity 8;

[0071] The depth h of the second cavity 8 is 45% of the total thickness H of the front cover plate.

[0072] The length of the first cavity 12 is 45% of the length of the blade.

[0073] The distance from the second joint line 7B on the back of the blade to the blade head is twice the average thickness of the blade.

[0074] The distance between the inner edge of the second cavity 8 and the outer edge of the sealing cone surface 10 is 30 mm.

[0075] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A large silicon carbide ceramic impeller, characterized in that: It is composed of several parts including multiple ceramic impeller bodies; the multiple ceramic impeller bodies are arranged in a circle, and each ceramic impeller body includes a front plate, a rear plate, a first blade plate and a second blade plate that are sintered into one body, wherein the front plate, the rear plate, the first blade plate and the second blade plate are surrounded to form a channel; the two ends of the channel are respectively connected to the suction port and the outlet of the ceramic impeller body; the first blade plate in the ceramic impeller body and the second blade plate in another adjacent ceramic impeller body are spliced ​​to form a blade, and a first cavity is provided in the middle of the blade, and the first cavity extends along the working surface of the blade toward the outlet direction of the ceramic impeller body; the extension length of the first cavity along the working surface of the blade toward the outlet direction of the ceramic impeller body is 30%-80% of the length of the blade.

2. The large silicon carbide ceramic impeller according to claim 1, characterized in that: The ceramic impeller body is made of reaction-sintered silicon carbide.

3. The large silicon carbide ceramic impeller according to claim 1 or 2, characterized in that: The joint line between two adjacent ceramic impeller bodies includes a first joint line and a second joint line, wherein the first joint line passes through the tail of the first cavity and the tail of the blade; the second joint line passes through the head of the first cavity and the working surface or back surface of the blade.

4. The large silicon carbide ceramic impeller according to claim 3, characterized in that: The distance between the second joint line from the working surface or the back surface of the impeller to the head of the blade is 1-2 times the average thickness of the blade.

5. The large silicon carbide ceramic impeller according to claim 1, characterized in that: The first blade plate of the ceramic impeller body is provided with a protrusion at its head position, and the head of the second blade plate of another ceramic impeller body adjacent to the ceramic impeller body after splicing is arranged at the rear end of the protrusion; or, the second blade plate of the ceramic impeller body is provided with a protrusion at its head position, and the head of the first blade plate of another ceramic impeller body adjacent to the ceramic impeller body after splicing is arranged at the rear end of the protrusion.

6. The large silicon carbide ceramic impeller according to claim 1, characterized in that: The front plate is provided with a second cavity, and the front lining plate is installed in the second cavity.

7. The large silicon carbide ceramic impeller according to claim 6, characterized in that: A second frame is also arranged in the second cavity, and the second frame is arranged at the lower end of the front lining plate.

8. The large silicon carbide ceramic impeller according to claim 6 or 7, characterized in that: The depth of the second cavity is 25%-75% of the thickness of the front cover plate, and the front cover plate includes a front plate and a front lining plate.

9. The large silicon carbide ceramic impeller according to claim 8, characterized in that: The ceramic impeller body is provided with a sealing cone surface at the position of the suction port thereof, and the distance from the inner edge of the second cavity to the outer edge of the sealing cone surface is 5mm-60mm.

10. The large silicon carbide ceramic impeller according to claim 1, characterized in that: The rear plate is provided with a third cavity, in which a third frame is installed; the first cavity is provided with a first frame; and the first frame and the third frame are connected.

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