Wear-resistant ceramic impeller

Abstract

The application discloses a wear-resistant ceramic impeller, mainly comprising an impeller body and a lining plate; the impeller body comprises blades, a front cover plate and a rear cover plate; the lining plate comprises blade lining plates, a front lining plate and a rear lining plate. The blades are arranged between the front cover plate and the rear cover plate and are integrally formed; cavities formed between adjacent blades, the front cover plate and the rear cover plate constitute flow channels for circulating slag slurry; the front lining plate is arranged on the front side of the flow channels and is fixedly connected with the front cover plate; the rear lining plate is arranged on the rear side of the flow channels and is fixedly connected with the rear cover plate; the blade lining plates are arranged on the working surfaces of the flow channels and are fixedly connected with the blades; low-stress coupling structures for reducing looseness and cracking are further arranged between the front lining plate and the front cover plate and between the rear lining plate and the rear cover plate. The application has the advantages of high wear resistance, high reliability and long service life.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of functional ceramic materials, and in particular to a high-wear-resistance silicon nitride / silicon carbide composite ceramic impeller. BACKGROUND

[0002] The impeller of a slurry pump is the most severely worn part of the slurry pump, and is generally made of wear-resistant alloy or wear-resistant rubber. However, in some severe wear conditions, the wear-resistant alloy impeller and the wear-resistant rubber impeller often cannot meet the use requirements. In order to improve the service life of the impeller, some technical solutions attempt to use ceramic materials to make the impeller. At present, a relatively mature process is to use silicon nitride combined with silicon carbide or reaction sintered silicon carbide to make the impeller. Reaction sintered silicon carbide has good wear resistance and can better resist the scouring of about 10 mm coarse particles in the medium. However, due to the process characteristics of reaction sintered silicon carbide, only small-sized impellers can be manufactured at present, because the reaction sintered silicon carbide product has a relatively high residual silicon, and the product has a relatively large residual internal stress after firing. With the increase of the size of the product, the residual internal stress increases sharply. When the diameter of the impeller is greater than 500 mm, the yield of the fired impeller product decreases sharply, and the impact resistance of the impeller is poor, and the reliability of the impeller often cannot meet the requirements. Silicon nitride combined with silicon carbide has 10-18% of pores in the product, and these pores can significantly reduce the residual stress of the product, so that the product has a high yield and good impact resistance. Therefore, silicon nitride combined with silicon carbide can be used to manufacture impellers with a diameter of about 1200 mm at present.

[0003] However, the wear resistance of silicon nitride combined with silicon carbide is generally low, and when the medium has about 10 mm coarse particles, the service life of the impeller is sharply shortened. In particular, the wear rate of the blade part of the impeller is much higher than that of other parts. In order to solve this problem, Chinese patent application 201921572753.4 discloses a ceramic impeller, which is made of silicon nitride combined with silicon carbide or oxides combined with silicon carbide, and a reinforcing ceramic piece made of silicon carbide is arranged on the head and working surface of the blade and is integrally sintered with the impeller body. The reinforcing ceramic piece can be reliably fixed on the impeller body because it is embedded in the front cover plate and the rear cover plate of the impeller. Therefore, the service life of the blade is obviously improved, and the service life of the impeller is significantly improved. However, in some severe wear conditions, the wear problem of the flow channel surface of the front cover plate and the rear cover plate becomes the key to the service life of the impeller after the service life of the blade is obviously improved by the impeller manufactured by the above-mentioned technology.

[0004] To further improve the life of the impeller, those skilled in the art would naturally think of setting a higher wear-resistant lining plate on the flow channel surface of the front cover plate and the rear cover plate. But we found in practice that how to reliably fix the lining plate on the relevant parts of the impeller is a quite difficult problem. The common methods to solve this problem are as follows, the first scheme is to make the lining plate separately first, reserve the installation space of the lining plate on the impeller body during forming, and then bond the lining plate on the reserved part after the impeller body is sintered separately; the second scheme is to make the lining plate of silicon carbide ceramic material first, bond and fix the lining plate on the flow channel lost foam of the impeller by referring to the method of Chinese application No. 201921572753.4, then put the flow channel lost foam fixed with the lining plate into the impeller mold, pour silicon nitride combined with silicon carbide ceramic material or oxide combined with silicon carbide ceramic material for forming, remove the lost foam after forming, and make the lining plate and the impeller body become one by sintering, to obtain an integrated sintered and formed impeller with lining plates set on the blade working surface, the front cover plate flow channel surface and the rear cover plate flow channel surface. There are three schemes for setting the front and rear lining plates in the second scheme, a scheme is to make the front or rear lining plate into an integral ring shape; b scheme is to make the front cover plate lining plate or the rear cover plate by many small mosaic ceramics; c scheme is to make the front cover plate lining plate or the rear cover plate lining plate by many ceramic pieces with shapes consistent with the front cover plate flow channel or the rear cover plate flow channel.

[0005] Our research found that the above several schemes in the implementation of the following problems: the first scheme problems is, due to the impeller body and the lining in the forming, drying and sintering process, inevitably exist deformation, the impeller body on the reserved lining installation space, it is difficult and lining better match, not only the surface precision of the impeller is poor, at the same time, the lining and the impeller body between the gap, the adhesive in these gaps is easy to be worn, due to the reliability of the bonding is not high, this makes the lining in use easy to fall off and lead to the impeller life to the expected. The second scheme a scheme problems is, if the size of the lining is larger, when the impeller sintering, the lining and the impeller body between the combination site easy to fall off, this fall off often difficult to be found in the test, even if found, also difficult to strengthen through the bonding process, therefore, the impeller in operation, due to the lining fall off lead to the impeller crushing probability is higher. Therefore, this scheme is only suitable for some size very small impeller, generally diameter is not more than 500 mm. The second scheme b scheme problems is, although a single small mosaic in the impeller sintering although the probability of fall off is lower, but due to the small mosaic size is smaller (generally thickness in 8-12 mm, width size in 20-30 mm), therefore, the number will be more, the lining fall off probability of the whole impeller will not be significantly reduced, at the same time, small mosaic combination difficult, not only the production efficiency is low, the flow surface quality is poor, and the ability of anti large particle erosion is poor, although this scheme can manufacture large size impeller, but the life of the impeller is not very obvious, many working conditions can not meet the use requirements; The second scheme c scheme problems is, the size of the lining ceramic piece is determined in a dilemma, when the size is larger, there is the same trend as a scheme, that is, the single lining fall off probability is higher; When the size is smaller, there is the same trend as b scheme, not only the ceramic piece is difficult to make, the combination difficulty is big, the impeller's resistance to coarse particle erosion performance also often can not meet the requirements, at the same time, due to the number of ceramic pieces is more, the lining fall off probability of the whole impeller is still higher.

[0006] Therefore, the ceramic impeller provided by the prior art cannot solve the problems of large size, reliability and service life of the impeller at the same time, which greatly limits its application. SUMMARY

[0007] The purpose of the present application is to overcome the shortcomings of the prior art and provide a ceramic impeller which is easy to be large-sized, has high reliability and has long service life.

[0008] The purpose of the present application is achieved by the following technical scheme:

[0009] The application discloses a wear-resistant ceramic impeller, which mainly comprises an impeller body and a lining plate sintered with the impeller body. The impeller body comprises blades, a front cover plate and a rear cover plate. The lining plate comprises blade lining plates, a front lining plate and a rear lining plate. The blades are arranged between the front cover plate and the rear cover plate and are integrally formed. Cavities formed between adjacent blades, the front cover plate and the rear cover plate constitute flow channels for circulating slurry. The front lining plate is arranged on the front side of the flow channels and is fixedly connected with the front cover plate. The rear lining plate is arranged on the rear side of the flow channels and is fixedly connected with the rear cover plate. The blade lining plates are arranged on the working surfaces of the flow channels and are fixedly connected with the blades. Low-stress coupling structures are further arranged between the front lining plate and the front cover plate and between the rear lining plate and the rear cover plate to reduce looseness and cracking.

[0010] As a preferred scheme of the application, the low-stress coupling structure comprises first through holes arranged on the front lining plate and / or the rear lining plate respectively and first connecting columns arranged on the first through holes respectively. The first connecting columns are integrally formed with the front cover plate and are matched with the corresponding first through holes on the front lining plate. The first connecting columns are integrally formed with the rear cover plate and are matched with the corresponding first through holes on the rear lining plate.

[0011] Preferably, the first through holes adopt a conical hole structure with a small inner diameter and a large outer diameter, or the area of the first connecting columns on the side close to the flow channels is larger than that on the other side.

[0012] As a preferred scheme of the application, the low-stress coupling structure comprises first isolation grooves arranged on the front lining plate and / or the rear lining plate respectively and first isolation tables arranged on the first isolation grooves respectively. The first isolation tables are integrally formed with the front cover plate and are matched with the corresponding first isolation grooves on the front lining plate. The first isolation tables are integrally formed with the rear cover plate and are matched with the corresponding first isolation grooves on the rear lining plate.

[0013] Preferably, the first isolation grooves extend from the edges of the front lining plate and / or the rear lining plate to the inside, or the first isolation grooves are arranged on the front lining plate or / and the inside of the front lining plate.

[0014] Preferably, the area of the first isolation tables on the side close to the flow channels is larger than that on the other side.

[0015] As a preferred scheme of the application, the low-stress coupling structure comprises second isolation grooves arranged on the blade lining plates and the front lining plate respectively and second isolation tables arranged on the second isolation grooves respectively. The second isolation grooves divide the blade lining plates and the front lining plate into a plurality of blocks, each of the front lining plates is fixedly connected with a corresponding blade lining plate, and the second isolation tables are integrally sintered with the front cover plate and the rear cover plate.

[0016] As a preferred scheme of the present application, the low stress coupling structure comprises a third isolation groove and a fourth isolation groove arranged on the front and / or rear backing plate. The third isolation groove divides the front and / or rear backing plate into several pieces. The fourth isolation groove is arranged inside the front and rear backing plate, or extends from the edge of the front and rear backing plate to the inside.

[0017] Preferably, the stress coupling structure further comprises a second through hole arranged on the front and / or rear backing plate respectively, and a second communication column arranged on the second through hole respectively. The second communication column is integrally sintered with the front cover plate. Or the second communication column is integrally sintered with the rear cover plate.

[0018] As a preferred scheme of the present application, the end of the backing plate is embedded in the impeller body to achieve fixed connection with the impeller body.

[0019] As a preferred scheme of the present application, the first communication column, the second communication column, the first isolation platform and the second isolation platform are infiltrated with organic adhesive, that is, the first through hole, the first isolation groove and the second isolation groove are infiltrated with organic adhesive.

[0020] The manufacturing method of the wear-resistant ceramic impeller provided by the present application is as follows: firstly, a blade backing plate, a front backing plate and a rear backing plate blank made of reaction sintered silicon carbide or pressureless sintered silicon carbide are manufactured by using a mold; then the above-mentioned blank is put into a reaction sintering furnace or a pressureless sintering furnace for sintering (primary sintering), and after cooling, the blade backing plate, the front backing plate and the rear backing plate are obtained; then the blade backing plate, the front backing plate and the rear backing plate are fixed on corresponding parts of an impeller core box lost foam by using an adhesive, the impeller core box lost foam with the fixed backing plates is put into an impeller mold, silicon nitride combined silicon carbide or oxide combined silicon carbide ceramic material is poured into the mold, and after forming (secondary forming), an impeller blank is obtained; after heating, the lost foam is removed, and the impeller blank is put into a nitriding furnace or an oxidizing furnace for sintering (secondary sintering), so that the impeller body is a ceramic impeller made of silicon nitride combined silicon carbide or oxide combined silicon carbide.

[0021] We have found in our research that when the silicon carbide ceramic and the silicon nitride combined silicon carbide or the oxide combined silicon carbide ceramic material of two different materials are formed and then subjected to secondary sintering, due to the difference in the expansion coefficients of the two materials, internal stress will be generated on the bonding surface of the two materials after cooling, and the greater the area or size of the bonding surface, the greater the internal stress. When the internal stress is greater than the bonding force generated between the backing plate and the impeller body due to sintering, the backing plate will be loose from the impeller body, and the probability of breaking of the backing plate or the impeller body will also be significantly increased. We have also found in our research that the smaller the curvature of the bonding surface of the two sintered ceramic materials, the greater the internal stress after sintering, and vice versa.

[0022] Compared with the prior art, the present application also has the following advantages:

[0023] (1)The lining plate of silicon carbide material and the impeller body of silicon nitride bonded silicon carbide or oxide bonded silicon carbide material can produce good bonding force between the two different materials of ceramics during secondary sintering, so that the lining plate and the impeller body can be better combined together. At the same time, the expansion coefficients of the two materials are relatively close, which can reduce the internal stress generated during secondary sintering and reduce the probability of the lining plate falling off along the combined part of the two; at the same time, the silicon nitride bonded silicon carbide or oxide bonded silicon carbide material has more pores, which is easy to manufacture large workpieces, so it is beneficial to the large-scale of the impeller.

[0024] (2)The front lining plate arranged on the surface of the front cover plate flow channel and arranged along the circumferential direction of the impeller axis, and the rear lining plate arranged on the surface of the rear cover plate flow channel and arranged along the circumferential direction of the impeller axis. This structure can use several front lining plates or rear lining plates of the same shape to cover the front cover plate flow channel surface or the rear cover plate flow channel surface that needs to increase the wear resistance, thereby reducing the size of the lining plate, reducing the stress of the combined surface of the lining plate and the impeller body after sintering, and reducing the specification and type of the front lining plate or the rear lining plate.

[0025] (3)Although the lining plate and the impeller body can produce a large bonding force during sintering, the flow channel surface where the front lining plate and the rear lining plate are located is generally a crescent-shaped plane with small curvature. For large impellers, it is easy to fall off after secondary sintering and cooling due to the large sintering stress. If a plurality of through holes are provided on the front lining plate or the rear lining plate, these through holes will be filled with ceramic casting material during the secondary forming process, and after sintering, a communication column that is integrally sintered with the impeller body and adapted to the through hole will be formed in the through hole. This structure not only increases the area of the bonding surface, but more importantly, it also increases the curvature of the front lining plate or the rear lining plate at the bonding site, and also significantly reduces the size of the front lining plate or the rear lining plate in the cross-sectional direction through the through hole. Therefore, the sintering stress on the bonding surface can be significantly reduced, which is beneficial to prevent the front lining plate or the rear lining plate from cracking or loosening along the bonding surface after sintering and cooling, improve the bonding strength between the two and the impeller body, and reduce the probability of the front lining plate, the rear lining plate or the impeller body breaking. At the same time, since the flow direction of the medium during the operation of the impeller is parallel to the working surface of the front lining plate or the rear lining plate, the front lining plate or the rear lining plate can protect the communication column in the through hole from being eroded by the medium.

[0026] (4)When the area of the through hole is large or the width size of the isolation groove is large, the communication column or the isolation platform is easy to be worn; on the contrary, during the forming and pouring of the impeller, the 1-3mm silicon carbide particles contained in the ceramic material are difficult to tightly fill the through hole or the isolation platform, which will reduce the strength and wear resistance of the communication column or the isolation platform. When the area of the communication column is between 25-400mm2 or the width size of the isolation platform is between 5-20mm, the above-mentioned contradiction can be better balanced.

[0027] (5) The isolation groove is set on the front or / and rear backing plate, and is filled with ceramic castable in the secondary forming process. After the secondary sintering, the isolation platform is formed in the isolation groove, which is adapted to the isolation platform and sintered with the impeller body as a whole. This structure can increase the area of the bonding surface, and more importantly, it can increase the curvature of the front or rear backing plate at these positions, and it can reduce the size of the cross section of the front or rear backing plate in the direction of the isolation groove. Therefore, the sintering stress on the bonding surface after the secondary sintering can be obviously reduced, which is beneficial to prevent the front or rear backing plate from cracking or loosening along the bonding surface, and improve the bonding strength between the front or rear backing plate and the impeller body. In addition, since the flow direction of the medium in the impeller is parallel to the working surface of the front or rear backing plate, the erosion of the medium to the isolation platform in the isolation groove is small, and the isolation platform with good wear resistance is protected by the backing plate and is not easy to be eroded.

[0028] (6) When the distance between adjacent through holes, between adjacent isolation grooves, or between the isolation groove and the adjacent through hole is too large, the stress generated during sintering is large, and the backing plate is prone to fall off. On the contrary, the total area of the through column or the isolation platform exposed to the flow surface is large, which can cause the wear resistance of the impeller to be significantly reduced. When the above distance is between 40-150mm, a balance between reliability and wear resistance can be obtained.

[0029] (7) When one end of the front or / and rear backing plate is inserted into the area where the blade and the cover plate (referring to the front cover plate or the rear cover plate) intersect, the inserted part of the backing plate can be fixed by the ceramic material of the impeller body, which is beneficial to improve the reliability of the fixation of the front or rear backing plate.

[0030] (8) The corresponding parts of one side of the rear or / and front backing plate and the blade backing plate are adapted to each other, which can make the gap between the front or rear backing plate and the blade backing plate small, and improve the wear resistance of the impeller.

[0031] (9) When the area of the through hole in one cross section away from the flow surface is smaller than the area of the other cross section close to the flow surface, the through column adapted to the through hole is an inner small and outer large structure (outer refers to the flow surface, and inner refers to the cross section away from the flow surface). In this way, the front or rear backing plate is constrained by the through column and is not easy to fall out, which is beneficial to improve the reliability of the impeller.

[0032] (10) When the width of the isolation groove in one cross section away from the flow surface is smaller than the width of the other cross section close to the flow surface, the isolation platform adapted to the isolation groove is an inner small and outer large structure. In this way, the front or rear backing plate is constrained by the isolation platform and is not easy to fall out, which is beneficial to improve the reliability of the impeller.

[0033] (11) The blade liner and the front or rear liner are made in one piece, which can significantly increase the curvature of the liner, i.e. the joint surface of the front or rear liner and the impeller body is no longer a plane, but a curved surface with a cross-section in the shape of the letter "7". The liner made in one piece has higher fixing reliability due to the constraints in several directions.

[0034] (12) The material of the communication column or the isolation platform made in one piece with the impeller body is silicon nitride or oxide combined silicon carbide, which has 12-18% apparent porosity, good compressive strength, but lower tensile and bending strength. The impeller is immersed in a low-viscosity adhesive, which can easily penetrate the pores of the communication column or the isolation platform and enter the joint surface of the front or rear liner and the impeller body. This can not only significantly improve the tensile and bending strength of the communication platform or the isolation platform, but also bond the impeller body and the liner along the joint surface, thereby improving the fixing reliability of the front or rear liner. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a sectional view of the impeller in Example 1 provided by the present application.

[0036] Figure 2 is a front view of the front liner in Example 1 provided by the present application. Figure 1

[0037] Figure 3 is a front view of the rear liner in Example 1 provided by the present application.

[0038] Figure 4 is a front view of the rear liner in Example 2 provided by the present application.

[0039] Figure 5 is a sectional view at X provided by the present application. Figure 1

[0040] Figure 6 is a schematic diagram of the impeller casting in Example 1 provided by the present application.

[0041] Figure 7 is a sectional view of the impeller in Example 2 provided by the present application.

[0042] Figure 8 is a sectional view at C-C provided by the present application. Figure 7

[0043] Figure 9 is a front view of the front liner in Example 2 provided by the present application.

[0044] Figure 10 is a front view of the rear liner in Example 2 provided by the present application.

[0045] Figure 11 ​​​is a sectional view of embodiment 3 provided by the present application. Figure 7 is a local enlarged view at Y.

[0046] Figure 12 is a sectional view of embodiment 3 provided by the present application.

[0047] Figure 13 is a sectional view of embodiment 3 provided by the present application. Figure 12 is a sectional view at E-E.

[0048] Figure 14 is a front view of the front lining plate in embodiment 3 provided by the present application.

[0049] Figure 15 is a front view of the rear lining plate in embodiment 3 provided by the present application.

[0050] Figure 16 is a sectional view of embodiment 4 provided by the present application.

[0051] Figure 17 is a sectional view of embodiment 4 provided by the present application. Figure 16 is a sectional view at G-G.

[0052] Figure 18 is a front view of the front lining plate in embodiment 4 provided by the present application.

[0053] Figure 19 is a sectional view of embodiment 5 provided by the present application.

[0054] Figure 20 is a sectional view of embodiment 5 provided by the present application. Figure 19 is a sectional view at I-I.

[0055] Figure 21 is a front view of the front lining plate and the small lining plate in embodiment 5 provided by the present application.

[0056] Explanation of the reference numerals in the above-described drawings:

[0057] 1 - impeller body, 2 - blade lining plate, 3 - front lining plate, 4 - rear lining plate, 5 - first through hole, 6 - first communication column, 7 - first isolation groove, 8 - first isolation platform, 9 - impeller core box, 10 - outer mold, 11 - pouring gate, 12 - small lining plate, 13 - second isolation groove, 14 - second isolation platform, 15 - third isolation groove, 16 - fourth isolation groove, 17 - second through hole, 18 - second communication column. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical scheme and advantages of the present application more clear and definite, the present application is further described below with reference to the drawings and by taking examples.

[0059] Example 1

[0060] AsFigures 1-6 As shown, Figure 1 for Figure 2 A cross-sectional view in section BB. The ceramic impeller in this embodiment includes an integrally sintered impeller body 1 and a liner. The impeller body 1 is made of silicon nitride bonded silicon carbide, and the liner is made of reaction-sintered silicon carbide; their coefficients of expansion are relatively close. Each blade pair is provided with a blade liner 2 located on the blade working surface and extending to the front and rear cover plates, a front liner 3 located on the flow channel surface of the front cover plate, and a rear liner 4 located on the flow channel surface of the rear cover plate. Each rear liner 4 and the front liner 3 are provided with four first through holes 5, which are conical in shape, and the distance between adjacent first through holes 5 is between 60-100 mm. (From...) Figure 5 (As can be seen in the enlarged view), the diameter of the first through hole 5 at the flow surface bb is 12mm and the diameter at the mating surface aa is 9mm. Therefore, the first connecting column 6, which is integrally sintered with the impeller body 1, is an inverted conical column with a larger outer diameter and a smaller inner diameter that is adapted to the first through hole 5. Its diameter at the flow surface bb is 12mm and its diameter at the smallest end aa is 9mm. Therefore, the area of ​​its cross-section away from the flow surface is smaller than the area of ​​its cross-section close to the flow surface. The first connecting column 6 can thus constrain the front liner 3 or the rear liner 4.

[0061] like Figure 2 As shown, one end of the front liner 3 and the rear liner 4 extends to the location where the blade intersects with the front or rear cover plate (shown by the dashed line). One side of the front liner 3 corresponds to the corresponding part of the blade liner 2.

[0062] The first connecting column 6 is permeated with vinyl resin with a viscosity of about 400 mPa·s. Due to its low viscosity, the resin can easily penetrate into the mating surface between the front liner 3 or the rear liner 4 and the impeller body 1 through the pores on the first connecting column 6. This not only improves the tensile and bending strength of the first connecting column 6, but also enhances the bonding force of the mating surface.

[0063] The manufacturing process of the impeller in this embodiment is as follows: First, blanks of the reaction-sintered material blade liner 2, front liner 3, and rear liner 4 are made, dried, and then sintered in a reaction sintering furnace with metallic silicon in a certain proportion. After cooling, the blade liner 2, front liner 3, and rear liner 4 are obtained, and then... Figure 6As shown, blade liner 2, front liner 3, and rear liner 4 are bonded to a lost foam impeller core box 9 made of polystyrene. The impeller core box 9 with the liner attached is then installed into an outer mold 10. Silicon nitride-bonded silicon carbide ceramic material is poured into the outer mold 10 through the pouring port 11. The main components of the ceramic material are silicon carbide particles, metallic silicon particles, binder, and water. Vibration molding is performed, and after the ceramic material hardens, an impeller blank is obtained. After drying, the impeller blank is placed in a nitriding furnace, and high-purity nitrogen is introduced. High-temperature sintering (secondary sintering) is carried out at a temperature of 50℃ / h. During the heating process, the impeller core box is burned off. At a temperature of about 1300℃, the metallic silicon in the ceramic material reacts with the nitrogen to generate silicon nitride. The temperature is further increased to about 1400℃ and held for 16 hours. After cooling, a wear-resistant ceramic impeller is obtained. The ceramic impeller is immersed in vinyl resin containing a curing agent for 1 hour. The impeller is then removed and heated to 120°C to cure the vinyl resin, thus obtaining the impeller of this embodiment.

[0064] Example 2

[0065] like Figures 7-11 As shown, Figure 7 for Figure 8 The cross-sectional view in section DD. The ceramic impeller in this embodiment includes an integrally sintered impeller body 1 and a liner. The impeller body 1 is made of oxide-bonded silicon carbide, and the liner is made of pressureless sintered silicon carbide. The expansion coefficients of the two are relatively close. The liner includes 5 blade liners 2 corresponding to the working surface of the blades and extending to the front cover plate and the rear cover plate, 5 front liners 3 corresponding to the flow channel surface of the front cover plate and arranged circumferentially along the impeller axis, and 5 rear liners 4 corresponding to the flow channel surface of the rear cover plate and arranged circumferentially along the impeller axis.

[0066] like Figure 8 , 9 As shown in Figure 10, each front liner 3 and rear liner 4 is provided with two first isolation grooves 7. The first isolation groove 7 is provided with a first isolation platform 8 which is integrally sintered with the impeller body 1 and is adapted to the isolation groove 7. The distance between adjacent first isolation grooves 7 is 70-75mm.

[0067] like Figure 11 As shown, the width of the first isolation groove 7 in the dd section is 13mm and the width of the first isolation groove 7 in the cc section is 10mm. Therefore, the partition platform 8 adapted to the first isolation groove 7 can constrain the front liner 3 or the rear liner 4.

[0068] The first isolation platform 8 is infiltrated with vinyl resin with a viscosity of about 400 mPa·S. Due to its low viscosity, the resin can penetrate into the mating surface between the front liner 4 or the rear liner 4 and the impeller body 1 through the pores on the first isolation platform 8. This not only improves the tensile strength of the first isolation platform 8, but also enhances the bonding force of the mating surface.

[0069] The manufacturing process of the impeller of the present embodiment is basically the same as that of Embodiment 1, except that the blanks of the blade liner 2, the front liner 3 and the rear liner 4 made of the material for pressureless sintering are first prepared and then put into a pressureless sintering furnace for primary sintering. The blade liner 2, the front liner 3 and the rear liner 4 are obtained. The blank of the impeller is formed by using the oxide combined carbon-silicon ceramic material, and after casting and drying, the blank of the impeller is obtained. The blank of the impeller is put into an oxidation furnace, and the temperature is raised at a rate of 50°C / h to about 1400°C for 12h for high-temperature sintering (secondary sintering). After cooling, the wear-resistant ceramic impeller is obtained.

[0070] Embodiment 3

[0071] As shown in Figures 12-15 , Figure 12 for Figure 13 In the cross-sectional view of F-F. The manufacturing process of the ceramic impeller in the present embodiment is basically the same as that of Embodiment 1, except that 2 blade liners 2, 2 front liners 3 and 2 rear liners 4 (divided by the second isolation groove 13 and the second isolation platform 14) are provided for each blade, wherein one front liner 3 and one blade liner 2 are made into one whole, and the other front liner 3 and the other blade liner 2 are made into one whole, and both of the two wholes include the second through hole 17.

[0072] Embodiment 4

[0073] As shown in Figures 16-18 , the structure and process of the present embodiment are basically the same as those of Embodiment 1, except that the front liner 3 provided for each blade is provided with 7 first through holes 5 and 2 first isolation grooves 7, the first through holes 5 are cylindrical with a diameter of 10mm, the distance between adjacent first through holes 5 is 110-130mm, the width of the first isolation groove 7 is 10mm, and the length is 160-180mm. The distance between adjacent first isolation grooves 7 is set to 100-130mm, and the distance between the first isolation groove 7 and the adjacent first through hole 5 is set to 50-90mm.

[0074] Embodiment 5

[0075] As shown in Figures 19-21As shown, the structure, process and example 1 of the embodiment are substantially the same, and the difference is mainly that the front lining plate 3 corresponding to each blade is provided with 4 second through holes 17 and 1 fourth isolation groove 16, the diameter of the second through hole 17 is 15 mm, the width of the fourth isolation groove 16 is 12 mm, and a small lining plate 12 (divided by the third isolation groove 15) is further provided. Since the size of the small lining plate 12 is small, the sintering stress generated during secondary sintering is small, and therefore no second through hole 17 and fourth isolation groove 16 are provided thereon, so that the manufacturing cost of the small lining plate 12 can be reduced. The distance between adjacent second through holes 17 is 90-110 mm, and the distance between the fourth isolation groove 16 and the adjacent second through hole 17 is 40-60 mm.

[0076] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above embodiments, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods and shall be within the scope of protection of the present application.

Claims

1. A wear-resistant ceramic impeller, characterized in that, The impeller includes an impeller body and a liner plate sintered integrally with the impeller body. The impeller body includes blades, a front cover plate, and a rear cover plate. The liner plate includes a blade liner plate, a front liner plate, and a rear liner plate. The blades are disposed between the front cover plate and the rear cover plate, and the three are integrally formed. The cavities formed between adjacent blades and the front and rear cover plates constitute a flow channel for slurry flow. The front liner plate is disposed on the front side of the flow channel and is fixedly connected to the front cover plate. The rear liner plate is disposed on the rear side of the flow channel and is fixedly connected to the rear cover plate. The blade liner plate is disposed on the working surface of the flow channel and is fixedly connected to the blades. A low-stress coupling structure is also provided between the front liner plate and the front cover plate, and between the rear liner plate and the rear cover plate. The low-stress coupling structure includes first through holes respectively disposed on the front liner and / or the rear liner, and first connecting posts respectively disposed on the first through holes; the first connecting posts are integrally formed with the front cover plate and are paired with the corresponding first through holes on the front liner; the first connecting posts are integrally formed with the rear cover plate and are paired with the corresponding first through holes on the rear liner. Alternatively, the low-stress coupling structure may include a first isolation groove and a first isolation platform respectively disposed on the front liner and / or the rear liner; the first isolation platform is integrally formed with the front cover plate and is paired with the corresponding first isolation groove on the front liner; the first isolation platform is integrally formed with the rear cover plate and is paired with the corresponding first isolation groove on the rear liner. Alternatively, the low-stress coupling structure may include a second isolation groove respectively disposed on the blade liner and / or the front liner, and a second isolation platform respectively disposed on the second isolation groove; the second isolation groove divides the blade liner and the front liner into several pieces, each front liner being connected and fixed to the corresponding blade liner, and the second isolation platform being integrally sintered with the front cover plate, the rear cover plate, and the blade; Alternatively, the low-stress coupling structure may include a third isolation groove and a fourth isolation groove disposed on the front liner and / or the rear liner; the third isolation groove divides the front liner and the rear side plate into several pieces; the fourth isolation groove is disposed inside the front liner and / or the rear liner, or extends inward from the edge of the front liner or the rear liner.

2. The wear-resistant ceramic impeller according to claim 1, characterized in that, The first through hole adopts a tapered hole structure with a smaller inner diameter and a larger outer diameter; or the area of ​​the first connecting column on the side near the flow channel is larger than the area on the other side.

3. The wear-resistant ceramic impeller according to claim 1, characterized in that, The area of ​​the first isolation platform on the side closest to the flow channel is larger than the area on the other side.

4. The wear-resistant ceramic impeller according to claim 1, characterized in that, The first isolation groove extends inward from the edge of the front liner or the rear liner, or the first isolation groove is disposed inside the front liner and / or the rear liner.

5. The wear-resistant ceramic impeller according to claim 1, characterized in that, The low-stress coupling structure further includes second through holes respectively disposed on the front liner and / or the rear liner, and second connecting posts respectively disposed on the second through holes; the second connecting posts are integrally sintered with the front cover plate, or the second connecting posts are integrally sintered with the rear cover plate.

6. The wear-resistant ceramic impeller according to claim 1, characterized in that, The end of the liner is embedded in the impeller body to achieve a fixed connection with the impeller body.

7. The wear-resistant ceramic impeller according to claim 1, characterized in that, The first through hole contains an organic adhesive.

8. The wear-resistant ceramic impeller according to claim 1, characterized in that, The first isolation groove contains organic adhesive.

9. The wear-resistant ceramic impeller according to claim 1, characterized in that, The second isolation tank contains organic adhesive.

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