Concrete conveying elbow pipe, pumping equipment and preparation method

Abstract

The present invention discloses a concrete conveying elbow, a pumping device and a preparation method. The concrete conveying elbow includes an outer pipe and an inner pipe. The inner pipe is disposed inside the outer pipe and includes a metal casting and a plurality of reinforcing columns. The metal casting is formed by casting and has an outer arc side and an inner arc side. The outer arc side and the inner arc side enclose a conveying channel for concrete to flow through. The plurality of reinforcing columns are arranged at intervals and cast and buried in the easily worn area of the outer arc side. The material of the reinforcing columns is ceramic or fiber whisker. Then, the inner pipe is made by casting the plurality of reinforcing columns into the metal casting using a casting process. The cast inner pipe is compounded with two materials, namely the metal casting and the reinforcing columns, which can achieve the purpose of increasing the toughness of the inner pipe, avoid the phenomenon of cracking and chipping of the inner pipe when the conveying elbow is impacted, and improve the service life of the conveying elbow.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete conveying, and particularly relates to a concrete conveying elbow, a pumping device and a preparation method thereof. Background Art

[0002] A concrete conveying elbow is a pipeline for a concrete pumping device such as a boom pump truck, a truck-mounted pump, a trailer pump, etc. to pump concrete to a destination. During the use of the concrete conveying elbow, in addition to the large pumping pressure, since the concrete itself often contains large-particle hard and angular aggregates, and the movement direction of the concrete changes at the conveying elbow, it is also required that the conveying elbow has excellent wear resistance and impact resistance.

[0003] Currently, double-layer conveying elbows are generally used for concrete conveying elbows. The double-layer conveying elbow is composed of an outer pipe, an inner pipe and two end flanges. The outer pipe is made of a carbon steel pipe with good toughness and can bear pressure, and the inner pipe is made of high-chromium cast iron for wear resistance. Since the double-layer conveying elbow bears a large impact force during actual use, and high-chromium cast iron is white cast iron, there are a large number of carbide hard phases in this tissue material, and the wear resistance is excellent. However, the carbide is brittle, and the material is prone to cracking and chipping when subjected to impact, resulting in a low service life of the conveying elbow. Summary of the Invention

[0004] In view of the above defects or deficiencies, the present invention provides a concrete conveying elbow, a pumping device and a preparation method thereof, aiming to solve the technical problem that the inner pipe of the double-layer conveying elbow is prone to cracking and chipping when subjected to impact.

[0005] To achieve the above object, the present invention provides a concrete conveying elbow, wherein the concrete conveying elbow includes an outer pipe and an inner pipe. The inner pipe is disposed inside the outer pipe and includes a metal casting and a plurality of reinforcing columns. The metal casting is formed by casting and has an outer arc side and an inner arc side. The outer arc side and the inner arc side enclose a conveying channel for concrete to flow through. The plurality of reinforcing columns are arranged at intervals and cast and buried in the easily worn area of the outer arc side. The material of the reinforcing column is ceramic or fiber whisker.

[0006] In an embodiment of the present invention, the easily worn area of the outer arc side includes two first easily worn areas disposed at the first end close to the conveying channel. The two first easily worn areas are arranged at intervals along the circumferential direction of the outer arc side and are symmetrically arranged on the outer arc side.

[0007] In an embodiment of the present invention, the outer arc side in the bending direction includes a first bending transition section, a first bending strengthening section and a second bending transition section sequentially arranged from the first end of the conveying channel. The central angle of the first bending transition section along the bending direction of the outer arc side is 12° - 18°, and the central angle of the first bending strengthening section along the bending direction of the outer arc side is 20° - 25°. The two first easily worn areas are located on the first bending strengthening section.

[0008] In an embodiment of the present invention, the first bending strengthening section includes, in the circumferential direction, a first circumferential transition section, a first circumferential strengthening section, a second circumferential transition section, a second circumferential strengthening section, and a third circumferential transition section arranged in sequence. The first circumferential transition section and the third circumferential transition section are symmetrically arranged. The central angles of the first circumferential transition section and the third circumferential transition section along the circumferential direction of the outer arc side are equal and are set to 30° - 40°. The first circumferential strengthening section and the second circumferential strengthening section are symmetrically arranged. The central angles of the first circumferential strengthening section and the second circumferential strengthening section along the circumferential direction of the outer arc side are equal and are set to 30° - 40°. Two first easily worn areas are respectively located on the first circumferential strengthening section and the second circumferential strengthening section.

[0009] In an embodiment of the present invention, on the outer arc side in the bending direction, there are further a second bending strengthening section and a third bending transition section arranged in sequence from the second bending transition section. The first bending transition section and the third bending transition section are symmetrically arranged. The first bending strengthening section and the second bending strengthening section are symmetrically arranged. The easily worn areas on the outer arc side further include two second easily worn areas, and the two second easily worn areas are located on the second bending strengthening section and are arranged at intervals along the circumferential direction of the second bending strengthening section.

[0010] In an embodiment of the present invention, the metal casting bulges outwards towards the outer pipe in the easily worn area.

[0011] In an embodiment of the present invention, the concrete conveying elbow further includes a fiber composite intermediate layer disposed between the outer pipe and the inner pipe.

[0012] In an embodiment of the present invention, the fiber composite intermediate layer includes alumina fibers, epoxy resin, and a curing agent.

[0013] In an embodiment of the present invention, the metal casting is a high chromium cast iron part.

[0014] To achieve the above object, the present invention further provides a pumping device, wherein the pumping device includes the concrete conveying elbow described above.

[0015] To achieve the above object, the present invention further provides a preparation method for a concrete conveying elbow, wherein the preparation method for the concrete conveying elbow is applied to prepare the concrete conveying elbow described above, and the preparation method for the concrete conveying elbow includes:

[0016] Prepare a lost foam model according to the shape of the metal casting and the casting positions of a plurality of reinforcing cylinders on the metal casting;

[0017] Fix a plurality of reinforcing cylinders on the lost foam model;

[0018] Inject metal casting solution into the lost foam model to prepare a cast-in-place inner pipe;

[0019] Uniformly lay a fiber composite intermediate layer on the outer wall of the inner pipe;

[0020] Insert the inner pipe with the fiber composite intermediate layer laid thereon into the outer pipe, and perform a necking operation on the outer pipe so that the inner pipe and the outer pipe are respectively cured and connected to the fiber composite intermediate layer.

[0021] Through the above technical solution, the concrete conveying elbow provided by the embodiment of the present invention has the following beneficial effects:

[0022] When using the above concrete conveying elbow, since the inner pipe includes a metal casting and a plurality of reinforcing columns, the metal casting is formed by casting and has an outer arc side and an inner arc side, and a conveying channel for concrete to flow through is formed by enclosing the outer arc side and the inner arc side. The plurality of reinforcing columns are arranged at intervals and cast and buried in the easily worn area of the outer arc side. That is, the inner pipe is made by using a casting process to cast and bury the plurality of reinforcing columns in the metal casting. The cast inner pipe is composed of two materials, namely the metal casting and the reinforcing columns. At the same time, the material of the reinforcing columns can be ceramic or fiber whisker, and the impact toughness of both ceramic and fiber whisker is higher than that of the metal casting. Then, the reinforcing columns cast on the metal casting can achieve the purpose of increasing the toughness of the inner pipe, avoiding the phenomenon of cracking and chipping of the inner pipe when the conveying elbow is impacted, and improving the service life of the conveying elbow.

[0023] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings are used to provide an understanding of the present invention and constitute a part of the specification. Together with the following specific implementation manners, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0025] Figure 1 is a schematic cross-sectional structure diagram of a concrete conveying elbow according to an embodiment of the present invention;

[0026] Figure 2 is Figure 1 the schematic structure diagrams of A-A, B-B, C-C and D-D in

[0027] Figure 3 is a partial structure schematic diagram of a cross-section of a plurality of reinforcing columns cast in the easily worn area according to an embodiment of the present invention;

[0028] Figure 4 is a partial structure schematic diagram of another cross-section of a plurality of reinforcing columns cast in the easily worn area according to an embodiment of the present invention.

[0029] DESCRIPTION OF THE REFERENCE NUMERALS

[0030] 1 Outer pipe 2 Inner pipe

[0031] 21 Metal casting 22 Reinforcing columns

[0032] 23 Outer arc side 231 First bending transition section

[0033] 232 First bending strengthening section 233 Second bending transition section

[0034] 234 Second bending strengthening section 235 Third bending transition section

[0035] 236 First circumferential transition section 237 First circumferential strengthening section

[0036] 238 Second circumferential transition section 239 Second circumferential strengthening section

[0037] 230 Third circumferential transition section 24 Inner arc side

[0038] 25 Conveying channel 3 Fiber composite intermediate layer

[0039] 4 Flange 5 Wear-resistant ring Specific embodiments

[0040] The following describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0041] The concrete conveying elbow of the present invention will be described below with reference to the accompanying drawings.

[0042] As Figure 1 and Figure 2 shown, the present invention provides a concrete conveying elbow, wherein the concrete conveying elbow includes:

[0043] Outer pipe 1;

[0044] Inner pipe 2, the inner pipe 2 is disposed inside the outer pipe 1 and includes a metal casting 21 and a plurality of reinforcing columns 22. The metal casting 21 is formed by casting and has an outer arc side 23 and an inner arc side 24. A conveying channel 25 for concrete to flow through is formed by enclosing the outer arc side 23 and the inner arc side 24. The plurality of reinforcing columns 22 are arranged at intervals and cast and buried in the easily worn area of the outer arc side 23. The material of the reinforcing columns 22 is ceramic or fiber whisker.

[0045] When using the above-mentioned concrete conveying elbow pipe, since the inner pipe 2 includes a metal casting 21 and a plurality of reinforcing columns 22, the metal casting 21 is formed by casting and has an outer arc side 23 and an inner arc side 24. The outer arc side 23 and the inner arc side 24 enclose a conveying channel 25 for concrete to flow through. The plurality of reinforcing columns 22 are arranged at intervals and cast and embedded in the easily worn area of the outer arc side 23. That is, the inner pipe 2 is made by using the casting process to cast and embed the plurality of reinforcing columns 22 in the metal casting 21. The cast inner pipe 2 is composed of two materials, namely the metal casting 21 and the reinforcing columns 22. At the same time, the material of the reinforcing columns 22 can be ceramic or fiber whisker. The impact toughness of ceramic and fiber whisker is higher than that of the metal casting 21. Then, the reinforcing columns 22 cast on the metal casting 21 can achieve the purpose of increasing the toughness of the inner pipe 2, avoiding the phenomenon of cracking and chipping of the inner pipe 2 when the conveying elbow pipe is impacted, and improving the service life of the conveying elbow pipe. In addition, the reinforcing columns 22 are cast in the easily worn area of the outer arc side 23 of the metal casting 21, which can also ensure that the weight of the conveying elbow pipe does not increase too much.

[0046] In the embodiment of the present invention, the easily worn area of the outer arc side 23 includes two first easily worn areas ([ Figure 1 the area between the middle cross-sections A-A and B-B) arranged at the first end close to the conveying channel 25. The two first easily worn areas are arranged at intervals along the circumferential direction of the outer arc side 23 and symmetrically arranged on the outer arc side 23. It should be particularly noted that the circumferential direction of the outer arc side 23 is also the circumferential direction of the inner pipe 2. After analyzing the failure parts of multiple physical conveying elbow pipes, it is known that the failure parts of the conveying elbow pipe are close to the inlet end of the conveying channel 25 of the conveying elbow pipe and intersect on the two first easily worn areas arranged at intervals and symmetrically along the circumferential direction of the outer arc side 23. Thus, part of the reinforcing columns 22 can be cast into the metal casting 21 corresponding to one of the first easily worn areas, part of the reinforcing columns 22 can be cast into the metal casting 21 corresponding to the other first easily worn area, and the first end of the conveying channel 25 is set as the inlet end, then the impact toughness of the inner pipe 2 can be improved and the occurrence of failure phenomena can be avoided.

[0047] See Figure 1 , in the embodiment of the present invention, the outer arc side 23 in the bending direction includes a first bending transition section 231, a first bending strengthening section 232 ([ Figure 1 the area between the middle cross-sections A-A and B-B) and a second bending transition section 233 ([ Figure 1(in the area between B-B and C-C), the central angle of the first bending transition section 231 along the bending direction of the outer arc side 23 can be 12° to 18°, and the central angle of the first bending strengthening section 232 along the bending direction of the outer arc side 23 can be 20° to 25°. The two first wear-prone areas are located on the first bending strengthening section 232. It should be particularly noted that the bending direction of the outer arc side 23 is the bending extension direction of the inner pipe 2. The bending angle of the inner pipe 2 can be 90°, so the bending angle of the outer arc side 23 is also 90°. After measuring and analyzing the failure parts of multiple physical conveying elbows, it is known that the position intersection of the two first wear-prone areas, which are the failure parts of the conveying elbow, on the bending direction of the outer arc side 23 is on the first bending strengthening section 232. Thus, the casting position of the reinforcing column 22 on the bending direction of the outer arc side 23 can be determined to ensure accurate strengthening treatment of the failure parts of the conveying elbow.

[0048] Specifically, the central angle of the first bending transition section 231 along the bending direction of the outer arc side 23 can be 15°, and the central angle of the first bending strengthening section 232 along the bending direction of the outer arc side 23 can be 22°. That is, when the first end of the conveying channel 25 (the starting end of the first bending transition section 231) is defined as the 0° central angle of the outer arc side 23 in the bending direction, the position of the first bending transition section 231 on the bending direction of the outer arc side 23 is within the range of 0° to 15°, and the position of the first bending strengthening section 232 on the bending direction of the outer arc side 23 is within the range of the central angle of 15° to 37°.

[0049] See Figure 2In the embodiment of the present invention, the first bending reinforcement segment 232 includes a first annular transition segment 236, a first annular reinforcement segment 237, a second annular transition segment 238, a second annular reinforcement segment 239 and a third annular transition segment 230 which are arranged in sequence in the annular direction. The first annular transition segment 236 and the third annular transition segment 230 are symmetrically arranged. The central angles of the first annular transition segment 236 and the third annular transition segment 230 along the annular direction of the outer arc side 23 are equal and set to 30°~40°. The first annular reinforcement segment 237 and the second annular reinforcement segment 239 are symmetrically arranged. The central angles of the first annular reinforcement segment 237 and the second annular reinforcement segment 239 along the annular direction of the outer arc side 23 are equal and set to 30°~40°. The two first easy-to-wear areas are respectively located on the first annular reinforcement segment 237 and the second annular reinforcement segment 239. It should be noted that the outer arc side 23 and the inner arc side 24 can be set in opposite directions, that is, the outer arc side 23 is the half side of the inner tube 2 facing the outer tube 1, and the inner arc side 24 is the half side of the inner tube 2 facing away from the outer tube 1. The center angle of the outer arc side 23 in the circumferential direction is 180°, and the first bending reinforcement section 232 is a section of the outer arc side 23 in the bending direction, and the center angle of the first bending reinforcement section 232 in the circumferential direction is also 180°. According to the measurement and analysis of the failure parts of multiple conveying elbows, it is known that the two first easy-to-wear areas of the failure parts of the conveying elbows intersect at the first circumferential reinforcement section 237 and the second circumferential reinforcement section 239 at the circumferential positions of the first bending reinforcement section 232, so that the casting position of the reinforcing column 22 in the circumferential direction of the outer arc side 23 can be determined to further ensure that the failure parts of the conveying elbows are accurately reinforced.

[0050] Specifically, the central angles of the first annular transition section 236 and the third annular transition section 230 along the annular direction of the outer arc side 23 can be set to 35°, and the central angles of the first annular reinforcement section 237 and the second annular reinforcement section 239 along the annular direction of the outer arc side 23 can be set to 35°. When the starting end of the first annular transition section 236 is positioned at the central angle of 0° in the annular direction of the first bending reinforcement section 232, the position of the first annular transition section 236 in the bending direction of the first bending reinforcement section 232 is in the range of 0° to 35°, the position of the first annular reinforcement section 237 in the bending direction of the first bending reinforcement section 232 is in the range of 35° to 70°, the position of the second annular transition section 238 in the bending direction of the first bending reinforcement section 232 is in the range of 70° to 110°, and the position of the second annular reinforcement section 239 in the bending direction of the first bending reinforcement section 232 is 110°. The position of the third annular transition section 230 on the bend of the first bend reinforcement section 232 is in the range of 145° to 180°.

[0051] Please see again Figure 1, in the embodiment of the present invention, on the outer arc side 23, in the bending direction, there are further provided a second bending strengthening section 234 ( Figure 1 the area between C-C and D-D in ), and a third bending transition section 235 arranged successively from the second bending transition section 233, that is, on the outer arc side 23, in the bending direction, there are arranged successively from the first end of the conveying channel 25 a first bending transition section 231, a first bending strengthening section 232, a second bending transition section 233, a second bending strengthening section 234, and a third bending transition section 235. The first bending transition section 231 and the third bending transition section 235 are symmetrically arranged, and the first bending strengthening section 232 and the second bending strengthening section 234 are symmetrically arranged. That is, the central angle of the third bending transition section 235 and the first bending transition section 231 in the bending direction of the outer arc side 23 is equal and set to 12° - 18°, preferably 15°. The central angle of the second bending strengthening section 234 and the first bending strengthening section 232 in the bending direction of the outer arc side 23 is equal and set to 20° - 25°, preferably 22°. The easily worn area of the outer arc side 23 further includes two second easily worn areas, and the two second easily worn areas are located on the second bending strengthening section 234 and are arranged at intervals along the circumferential direction of the second bending strengthening section 234. That is, the two first easily worn areas are located on the first bending strengthening section 232, close to the first end of the conveying channel 25, and the two second easily worn areas are located on the second bending strengthening section 234, close to the second end of the conveying channel 25. A plurality of reinforcing columns 22 can be cast and embedded in the metal casting 21 of the two first easily worn areas and the two second easily worn areas. Even if the conveying elbow has no directionality during assembly, whether the first end or the second end of the conveying channel 25 is used as the inlet end of the conveying elbow, there are reinforcing columns 22 at the positions where the conveying elbow is prone to failure.

[0052] Specifically, the structure of the second bending strengthening section 234 in the circumferential direction is the same as that of the first bending strengthening section 232 in the circumferential direction, including successively arranged a first circumferential transition section 236, a first circumferential strengthening section 237, a second circumferential transition section 238, a second circumferential strengthening section 239, and a third circumferential transition section 230.

[0053] Please refer to again Figure 1 and Figure 2, in the embodiment of the present invention, the metal casting 21 protrudes and bulges towards the outer tube 1 in the easily worn area. That is, when the metal casting 21 is cast and formed, the easily worn area is also thickened to further improve the impact resistance of the outer arc side 23. Specifically, the easily worn areas on the entire outer arc side 23 include two first easily worn areas disposed on the first bending strengthening section 232 near the first end of the conveying channel 25, and two second easily worn areas disposed on the second bending strengthening section 234 near the second end of the conveying channel 25. Then, on the four easily worn areas of the outer arc side 23, not only are a plurality of reinforcing columns 22 respectively cast and buried, but also four thickened portions protruding and bulging towards the outer tube 1 are formed. The height direction of the reinforcing columns 22 is arranged along the thickness direction of the outer arc side 23. That is, the height of the reinforcing columns 22 can be specifically determined according to the size of the thickening of the outer arc side 23. Then, thickening in the easily worn area also facilitates the casting of the reinforcing columns 22, and fixed-point thickening is also beneficial to ensuring the lightweight design of the inner tube 2.

[0054] In the prior art, there are studies on thickening the concrete conveying elbow to improve its strength, mainly in the following directions: First, a wear-resistant layer is provided at the central position of the longitudinal section of the conveying elbow (taking a 90° elbow as an example, in the left and right areas of the center line with an angle of 45° to the horizontal line), or a thickened portion is provided at the central position of the longitudinal section of the conveying elbow to make the thickness at this position the largest; Second, the conveying elbow is thickened as a whole. It can be seen that, no matter what kind of thickening method, the thickness of the traditional conveying elbow is the largest at the central position of the longitudinal section of the conveying elbow, wrongly believing that the central position of the longitudinal section of the conveying elbow is the failure part of the conveying elbow. The reason is the lack of research on the worn-out conveying elbows. Based on a large number of studies on the worn-out conveying elbows, the present invention finds that the failure parts of the conveying elbows should be the two easily worn areas on the outer arc side 23 near the inlet end (if the first end of the conveying channel 25 is used as the inlet end, the failure parts are the two first easily worn areas; if the second end of the conveying channel 25 is used as the inlet end, the failure parts are the two second easily worn areas). For the concrete conveying elbows provided in the prior art, a larger thickness is set at the position where the conveying elbow is not likely to fail, which leads to defects such as waste of the manufacturing materials of the conveying elbow and short service life. The embodiment of the present invention not only re-determines the easily failed parts of the conveying elbow, but also casts reinforcing columns 22 at these easily failed parts and can also be thickened. Then, without increasing the manufacturing materials of the conveying elbow, the weight of the conveying elbow does not increase, realizing lightweight, but obtaining a higher service life.

[0055] In an embodiment of the present invention, before casting the reinforcing column 22 into the metal casting 21, a metal activation coating can be first coated on the surface of the reinforcing column 22 by chemical vapor deposition. The metal activation coating can be a titanium coating or a nickel coating, and the coating thickness can be 10 μm - 40 μm. The metal activation coating is used to improve the adhesion ability with the metal casting 21 during casting. The reinforcing column 22 can be a cylinder, a cuboid or a C-shaped cross-section column. After the inner tube 2 is cast and formed, the reinforcing column 22 is cast and buried in the metal casting 21.

[0056] In an embodiment of the present invention, as shown in FIGS. 2 and Figure 3 shown, Figure 3 the E direction in is the bending direction of the outer arc side 23, the F direction is the circumferential direction of the outer arc side 23, and the height direction of the reinforcing column 22 can be set along the bending direction of the outer arc side 23. Since the bending angle of the outer arc side 23 in the bending direction is smaller than the bending angle of the outer arc side 23 in the circumferential direction, setting the height direction of the reinforcing column 22 along the bending direction of the outer arc side 23 is more beneficial for the layout design of multiple reinforcing columns 22. Of course, the present invention is not limited to this, and the height direction of the reinforcing column 22 can also be set along the thickness direction of the outer arc side 23.

[0057] In addition, the reinforcing columns 22 can be evenly spaced in both the bending direction and the circumferential direction of the outer arc side 23. The specific layout design can be arranged accordingly according to the size of the reinforcing column 22 and the size of the easily worn area. At the same time, as shown in Figure 2 and Figure 4 , Figure 4 the F direction in is the circumferential direction of the outer arc side 23, the H direction is the thickness direction of the outer arc side 23. In the same easily worn area, multiple reinforcing columns 22 can also be arranged in at least two layers in the thickness direction of the outer arc side 23, and at least two layers of reinforcing columns 22 can be correspondingly cast and buried in the thickened part protruding and bulging towards the outer tube 1 in the easily worn area.

[0058] In an embodiment of the present invention, the height of the reinforcing column 22 can be 4 mm - 6 mm, and the maximum span of the cross-section of the reinforcing column 22 can be 4 mm - 6 mm, so that the height and cross-sectional dimensions of the reinforcing column 22 are within a certain size range, which can ensure that the reinforcing column 22 achieves the purpose of improving the toughness of the inner tube in the metal casting 21. Specifically, the height of the reinforcing column 22 can be 5 mm, and the maximum span of the cross-section of the reinforcing column 22 can be 5 mm. Then when the reinforcing column 22 is a cylinder, the height of the cylinder can be 5 mm and the diameter can be 5 mm. In addition, the size of the required reinforcing column can be accurately obtained by polishing the reinforcing column 22 with sandpaper.

[0059] Please refer to Figure 1 and Figure 2, in the embodiment of the present invention, the concrete conveying elbow further includes a fiber composite intermediate layer 3 disposed between the outer pipe 1 and the inner pipe 2. The filling of the fiber composite intermediate layer 3 can further play a strengthening role, and the fiber composite intermediate layer 3 can block the heat transfer in the welding area of the flange 4, avoid the reduction of the hardness of the inner pipe 2 in the welding area, and improve the service life of the conveying elbow. Of course, the present invention is not limited to this, and it is also possible to fill concrete between the outer pipe 1 and the inner pipe 2. In addition, since the metal casting 21 is thickened in the easily worn area on the outer arc side 23, the metal casting 21 bulges outwards towards the outer pipe 1 corresponding to the easily worn area. Then, the fiber composite intermediate layer 3 on the outer wall of the outer arc side 23 needs to fill the depression of the outer arc side 23 and completely cover the fiber composite intermediate layer 3 between the outer wall of the entire outer arc side 23 and the inner wall of the outer pipe 1. By doing so, the wall thickness of the conveying elbow is designed with unequal thickness on both the inner and outer sides.

[0060] In the embodiment of the present invention, the fiber composite intermediate layer 3 includes alumina fiber, epoxy resin and curing agent. The curing agent can be one or more of polysebacic anhydride and cyclopentanetetracarboxylic dianhydride. In addition, the fiber composite intermediate layer 3 can also include a modifier, and the modifier can be one of polyamide resin, polyvinyl alcohol tert-butyl aldehyde and nitrile rubber. Selecting the modifier can improve the brittleness of the resin, enhance the bonding ability and impact toughness of the resin, and prevent the fiber composite intermediate layer 3 from cracking due to brittleness. Specifically, the mass ratio of epoxy resin, alumina fiber, curing agent and modifier can be 100:(50-70):(40-70):(15-40).

[0061] In the embodiment of the present invention, the metal casting 21 can be a high-chromium cast iron part. Of course, the present invention is not limited to this, and metal castings 21 made of other suitable materials are also possible. At the same time, the ceramic material of the reinforcing cylinder 22 can be 80%-99% alumina ceramic, silicon carbide ceramic or silicon nitride ceramic.

[0062] In the embodiment of the present invention, the concrete conveying elbow further includes a flange 4 and a wear-resistant ring 5. The flange 4 is welded to the end of the outer pipe 1, and the wear-resistant ring 5 is inserted into the flange 4 and welded to the inner pipe 2. Specifically, the material of the flange 4 can be low-carbon steel, and the wear-resistant ring 5 can be cast from high-chromium cast iron or high-carbon steel.

[0063] In the embodiment of the present invention, the material of the outer pipe 1 can be seamless pipe or welded pipe made of low-carbon steel or low-carbon alloy.

[0064] In addition, the present invention also provides a pumping device. The pumping device includes the concrete conveying elbow described above. Since the pumping device adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0065] To achieve the above object, the present invention further provides a preparation method of a concrete conveying elbow. Among them, it is applied to prepare the concrete conveying elbow according to the above, and the preparation method of the concrete conveying elbow includes:

[0066] Step 100: Prepare a lost foam model according to the shape of the metal casting body 21 and the casting positions of multiple reinforcing columns 22 on the metal casting body 21.

[0067] Specifically, the shape of the metal casting body 21 can be designed according to the determined easily worn area on the outer arc side 23 of the inner pipe 2, including: providing a space for accommodating the reinforcing column 22 in the easily worn area, and thickening the easily worn area. Then, prepare a lost foam model according to the designed metal casting body 21. The lost foam model can be made of foam or paraffin, specifically polystyrene foam.

[0068] Step 200: Fix multiple reinforcing columns 22 on the lost foam model.

[0069] Specifically, after the lost foam model is prepared, place multiple reinforcing columns 22 corresponding to the easily worn area in the pre-designed accommodation space of the lost foam model. In addition, before fixing the reinforcing column 22 on the lost foam model, the reinforcing column 22 can be polished with sandpaper first, washed and dried repeatedly. After drying, a metal activation coating is coated on the surface of the reinforcing column 22 by chemical vapor deposition method. The metal activation coating can be a titanium coating or a nickel coating, and the coating thickness can be 10μm - 40μm.

[0070] Step 300: Inject metal casting solution into the lost foam model to prepare the cast inner pipe 2.

[0071] Furthermore, adopt the lost foam casting process, inject metal casting solution into the lost foam model to obtain a metal casting body 21 cast with multiple reinforcing columns 22, so that the prepared inner pipe 2 is composed of two materials of the metal casting body 21 and the reinforcing column 22.

[0072] Step 400: Uniformly lay a fiber composite intermediate layer 3 on the outer wall of the inner pipe 2.

[0073] Further, after obtaining the cast inner tube 2, shot peening can be performed on the outer wall of the inner tube 2 and the inner wall of the outer tube 1, with a surface roughness of Ra1.5 - Ra4.5, to increase the bonding force between the fiber composite material and the inner and outer tubes 1. Then, a fiber composite intermediate layer 3 is uniformly laid or wound on the outer wall of the inner tube 2. The fiber composite intermediate layer 3 includes alumina fibers, epoxy resin, and a curing agent. The curing agent can be one or more of polysebacic anhydride and dicyclopentane tetracarboxylic dianhydride. In addition, the fiber composite intermediate layer 3 can also include a modifier, and the modifier can be one of polyamide resin, polyvinyl alcohol tert-butyl aldehyde, and nitrile rubber. Selecting a modifier can improve the brittleness of the resin, enhance the bonding ability and impact toughness of the resin, and prevent the fiber composite intermediate layer 3 from cracking due to brittleness.

[0074] Step 500: Insert the inner tube 2 provided with the fiber composite intermediate layer 3 into the outer tube 1, and perform a necking operation on the outer tube 1 so that the inner tube 2 and the outer tube 1 are respectively cured and connected to the fiber composite intermediate layer 3.

[0075] More specifically, insert the inner tube 2 with the fiber composite intermediate layer 3 coated on its outer surface into the outer tube 1, and then use a machining process to neck the outer tube 1. During the necking process of the outer tube 1, a part of the fiber composite intermediate layer 3 will be extruded. After the necking operation is completed, both the inner tube 2 and the outer tube 1 can be cured and connected to the fiber composite intermediate layer 3.

[0076] The following example is based on Al with a mass content of 99% and a cylindrical shape 2 O 3 ceramics as the reinforcing cylinder and high chromium cast iron as the metal casting of the inner tube for illustration, but it should not be regarded as a limitation to the present invention.

[0077] Example 1:

[0078] The outer tube is a Q345 seamless steel pipe, the inner tube is a high chromium cast iron seamless casting tube with ceramic reinforcing cylinders added. The fiber composite intermediate layer between the inner and outer tubes is a mixture of epoxy resin, alumina fiber material, polysebacic anhydride, and polyamide resin, with a mass ratio of 100:55:40:15. The two end flanges are Q345, and the wear-resistant ring is high chromium cast iron.

[0079] The preparation method of the conveying elbow specifically includes the following steps:

[0080] (1) A cylindrical alumina ceramic reinforcing cylinder with a height of 5 mm and a diameter of 5 mm is mechanically roughed with sandpaper to accurately determine the dimensions of the required ceramic reinforcing cylinder. Then, it is placed in distilled water and anhydrous ethanol and cleaned in an ultrasonic cleaner for 15 minutes, and then dried in a drying oven for later use.

[0081] (2) Weigh 1.5 g of I2 and 0.5 g of Ti, and the reaction material I 2 , Ti, and the ceramic reinforcing column are placed at the tail of the quartz tube. Then, the quartz tube is placed in a programmable furnace, evacuated, and filled with argon three times repeatedly to obtain a high oxygen-free state and a relatively pure argon protective atmosphere inside the quartz tube. After that, the argon flow rate is adjusted to 80 mL / min to act as the protective gas and the carrier gas. It is heated to the deposition temperature of 1150 °C at a rate of 15 - 20 °C / min, held for 60 min, cooled to room temperature in the furnace, and the ceramic reinforcing column is taken out and its surface is repeatedly cleaned and dried to obtain a ceramic reinforcing column with a Ti coating on the surface that is uniformly continuous and has a thickness of 10 μm - 40 μm.

[0082] (3) Cut the polystyrene foam board with a resistance wire, and design the lost foam model according to requirements, that is, a lost foam model with multiple cylindrical concave parts. Then, the processed polystyrene foam model and the riser model are combined and bonded together to form a model cluster.

[0083] (4) Place the ceramic reinforcing column coated with a titanium coating into the corresponding concave part of the lost foam. To ensure that the ceramic reinforcing column does not drift during the pouring process, fix an iron nail on the exposed surface of each ceramic reinforcing column with iron paste. The lost foam model with the fixed ceramic reinforcing column is painted with lost foam coating twice, and the coating thickness is 1 - 2 mm. After each coating, the lost foam model is placed in a drying room at 50 °C and dried for 5 h. Then, the lost foam model is buried in the sand box, and the iron nail on the ceramic reinforcing column is inserted into the sand box to fix the ceramic reinforcing column during the entire pouring process (the iron nail on the ceramic reinforcing column is fixed in the easily worn area on the outer arc side of the inner tube). It is sealed, evacuated to about 0.05 MPa to facilitate the rapid filling of the metal casting solution and the rapid disappearance of the lost foam model, and then the high chromium cast iron metal casting solution is poured. The pouring temperature is about 1400 °C. The pouring operation process is slow - fast - slow, and continuous pouring is maintained. The lost foam model disappears as the high chromium cast iron metal casting solution flows in. During the entire pouring process and for 10 - 20 min after pouring, the vacuum system remains open to facilitate the timely discharge of gas. After cooling, the casting is directly taken out of the sand box, and the casting is naturally separated from the dry sand. The cooled metal casting tightly wraps the ceramic reinforcing column, and the ceramic and the metal matrix part solidify into one body to form a ceramic / metal matrix composite layer, thereby obtaining a high chromium cast iron inner tube with a ceramic reinforcing column added.

[0084] (5) Perform shot peening on the outer wall of the inner tube and the inner wall of the outer tube, with a surface roughness of Ra2.7; then evenly lay a fiber composite intermediate layer on the outer wall of the inner tube, with a thickness of 1 mm.

[0085] (6) Mechanically compound the inner and outer pipes, and install flanges and wear-resistant rings at both ends of the compounded double-layer metal pipe.

[0086] (7) Finally, paint the conveying elbow, with the painting temperature being 150 °C and the heat preservation time being 1.0 h.

[0087] Comparative Example 1:

[0088] The outer pipe is a Q345 seamless steel pipe, the inner pipe is a high-chromium cast iron seamless casting pipe, there is no filler between the inner and outer pipes, the flanges at both ends are Q345, and the wear-resistant ring is high-chromium cast iron.

[0089] The preparation method of the conveying elbow specifically includes the following steps: Select a casting mold, pour the high-chromium cast iron solution into the cavity of the casting mold to obtain a high-chromium cast iron inner elbow, and the hardness of the inner elbow is 65 HRC; Mechanically compound the inner and outer pipes by cold drawing, and install flange welding at both ends of the compounded double-layer elbow; Finally, paint the conveying elbow, with the painting temperature being 150 °C and the heat preservation time being 1.0 h.

[0090] Comparative Example 2:

[0091] The outer pipe is a Q345 seamless steel pipe, the inner pipe is a high-chromium cast iron seamless casting pipe, there is no filler between the inner and outer pipes, the flanges at both ends are Q345, and the wear-resistant ring is high-chromium cast iron.

[0092] The preparation method of the conveying elbow specifically includes the following steps: Select a casting mold, pour the high-chromium cast iron solution into the cavity of the casting mold to obtain the pipe body of the high-chromium cast iron elbow, and the hardness of the inner pipe is 65 HRC; Mechanically compound the inner and outer pipes by cold drawing, and install flanges and wear-resistant rings at both ends of the compounded double-layer elbow; Finally, paint the conveying elbow, with the painting temperature being 150 °C and the heat preservation time being 1.0 h.

[0093] Conduct loading tests on the finished conveying elbows of Example 1, Comparative Example 1 and 2, and the results are as follows:

[0094] Service life Failure mode Example 1 85,000 cubic meters The inner pipe has no cracks and no peeling, and is normally worn through Comparative example 1 54,000 cubic meters The inner pipe has cracks and local fragmentation and peeling Comparative example 2 32,000 cubic meters The hardness at the flange weld decreases, resulting in reduced wear resistance and causing early failure

[0095] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0096] In the present invention, unless otherwise clearly specified or limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0097] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "exemplifications", "specific exemplifications", or "some exemplifications", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or exemplification are included in at least one embodiment or exemplification of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or exemplification. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or exemplifications. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or exemplifications described in this specification and the features of different embodiments or exemplifications.

[0098] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A concrete conveying elbow, characterized in that, the concrete conveying elbow comprises: an outer pipe (1); an inner pipe (2) which is arranged inside the outer pipe (1) and comprises a metal casting (21) and a plurality of reinforcing cylinders (22). The metal casting (21) is formed by casting and has an outer arc side (23) and an inner arc side (24). A conveying channel (25) for concrete to flow through is formed by enclosing the outer arc side (23) and the inner arc side (24). The plurality of reinforcing cylinders (22) are arranged at intervals and cast and buried in the easily worn area of the outer arc side (23). The material of the reinforcing cylinders (22) is ceramic or fiber whisker; the easily worn area of the outer arc side (23) includes a first easily worn area arranged near the first end of the conveying channel (25). The first easily worn area bulges outwards in the circumferential direction of the outer arc side (23) so that the plurality of reinforcing cylinders (22) can be laid in multiple layers in the direction from inside to outside.

2. The concrete conveying elbow according to claim 1, characterized in that, the easily worn area of the outer arc side (23) includes two first easily worn areas arranged near the first end of the conveying channel (25). The two first easily worn areas are arranged at intervals in the circumferential direction of the outer arc side (23) and are symmetrically arranged on the outer arc side (23).

3. The concrete conveying elbow according to claim 2, characterized in that, the outer arc side (23) in the bending direction includes a first bending transition section (231), a first bending strengthening section (232) and a second bending transition section (233) which are sequentially arranged from the first end of the conveying channel (25). The central angle of the first bending transition section (231) along the bending direction of the outer arc side (23) is 12° - 18°, and the central angle of the first bending strengthening section (232) along the bending direction of the outer arc side (23) is 20° - 25°. The two first easily worn areas are located on the first bending strengthening section (232).

4. The concrete conveying elbow according to claim 3, characterized in that, the first bending strengthening section (232) includes a first circumferential transition section (236), a first circumferential strengthening section (237), a second circumferential transition section (238), a second circumferential strengthening section (239) and a third circumferential transition section (230) which are sequentially arranged in the circumferential direction. The first circumferential transition section (236) and the third circumferential transition section (230) are symmetrically arranged. The central angles of the first circumferential transition section (236) and the third circumferential transition section (230) along the circumferential direction of the outer arc side (23) are equal and are set to 30° - 40°. The first circumferential strengthening section (237) and the second circumferential strengthening section (239) are symmetrically arranged. The central angles of the first circumferential strengthening section (237) and the second circumferential strengthening section (239) along the circumferential direction of the outer arc side (23) are equal and are set to 30° - 40°. The two first easily worn areas are respectively located on the first circumferential strengthening section (237) and the second circumferential strengthening section (239).

5. The concrete conveying elbow according to claim 3, characterized in that, on the outer arc side (23) in the bending direction, there are further provided a second bending strengthening section (234) and a third bending transition section (235) successively arranged from the second bending transition section (233). The first bending transition section (231) and the third bending transition section (235) are symmetrically arranged, the first bending strengthening section (232) and the second bending strengthening section (234) are symmetrically arranged, and the easily worn areas of the outer arc side (23) further include two second easily worn areas, and the two second easily worn areas are located in the second bending strengthening section (234) and are arranged at intervals along the circumferential direction of the second bending strengthening section (234).

6. The concrete conveying elbow according to any one of claims 1 to 5, characterized in that, the metal casting (21) protrudes and bulges towards the outer pipe (1) in the easily worn area.

7. The concrete conveying elbow according to any one of claims 1 to 5, characterized in that, the concrete conveying elbow further includes a fiber composite intermediate layer (3) disposed between the outer pipe (1) and the inner pipe (2).

8. The concrete conveying elbow according to claim 7, characterized in that, the fiber composite intermediate layer (3) includes alumina fibers, epoxy resin and a curing agent.

9. The concrete conveying elbow according to any one of claims 1 to 5, characterized in that, the metal casting (21) is a high chromium cast iron part.

10. A pumping device, characterized in that, the pumping device includes the concrete conveying elbow according to any one of claims 1 to 9.

11. A preparation method of a concrete conveying elbow, characterized in that, applied to prepare the concrete conveying elbow according to any one of claims 1 to 9, and the preparation method of the concrete conveying elbow includes: preparing a lost foam model according to the shape of the metal casting (21) and the casting positions of a plurality of reinforcing cylinders (22) on the metal casting (21); fixing the plurality of reinforcing cylinders (22) on the lost foam model; injecting a metal casting solution into the lost foam model to prepare a cast inner pipe (2); uniformly laying a fiber composite intermediate layer (3) on the outer wall of the inner pipe (2); inserting the inner pipe (2) provided with the fiber composite intermediate layer (3) into the outer pipe (1), and performing a diameter reduction operation on the outer pipe (1) so that the inner pipe (2) and the outer pipe (1) are respectively cured and connected with the fiber composite intermediate layer (3).

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