Concrete delivery pipe and preparation method thereof, and concrete pump truck

Abstract

The present invention relates to the field of engineering machinery technology, and discloses a concrete delivery pipe and a preparation method thereof, and a concrete pump truck. The concrete delivery pipe comprises an inner pipe, an outer pipe, and an intermediate layer arranged in the gap between the inner pipe and the outer pipe, wherein the first material composition forming the intermediate layer contains the following components which are preserved independently or two or more of them are mixed and preserved: epoxy resin, component A, and component B; relative to 100 parts by weight of epoxy resin, the content of component A is 60-120 parts by weight, and the content of component B is 140-180 parts by weight. The concrete delivery pipe provided by the present invention can prevent the delivery pipe from bursting due to excessive pressure, and can also prevent the hardness of the inner pipe from decreasing, thereby improving the wear resistance of the inner pipe.

Description

Technical Field

[0001] The invention relates to the technical field of engineering machinery, and in particular to a concrete conveying pipe and a preparation method thereof, and a concrete pump truck. Background Art

[0002] Concrete delivery pipe is the pipeline used by concrete pumping equipment such as pump trucks, vehicle-mounted pumps, and trailer pumps to pump concrete to the destination. In addition to the high pumping pressure during concrete delivery, the concrete itself is also very complex and often contains large particles of hard and sharp aggregates. This requires that the concrete delivery pipe must not only be able to withstand the pumping pressure, but also have excellent wear resistance.

[0003] At present, concrete delivery pipes can be divided into two categories: single-layer pipes and double-layer pipes. Among them, the single-layer pipe forms a 1-2mm thick hardened layer on the inner side of the delivery pipe through induction quenching of the inner wall to achieve a wear-resistant effect.

[0004] CN111156353A discloses a delivery pipe for a concrete pump truck, comprising: a pipe body and a pair of mounting flanges sleeved on both ends of the pipe body, wherein the pipe body is a seamless steel pipe, and the seamless steel pipe comprises the following components by weight percentage: 0.6-0.65% carbon, 0.75-1.00% manganese, 0.2-0.35% silicon, 0.25-0.75% chromium, 0.01-0.05% titanium, 0.1-0.25% copper, and no more than 0.02% phosphorus, no more than 0.15% sulfur, no more than 0.2% nickel, and the balance is iron.

[0005] The aforementioned single-layer conveying pipe has strong pressure-bearing capacity and simple preparation process, but the hardened layer is thin and the hardness is low, so it is not wear-resistant and has a short service life. In addition, the use of a single-layer pipe flange welding process does not solve the problem of reduced hardness of the conveying pipe in the welding area. On the contrary, the use of this process leads to the risk of further reduction in the hardness of the flange welding area.

[0006] In addition, double-layer pipes are usually mechanically compounded to form inner and outer pipes, and then induction hardened. The outer pipe of the double-layer pipe is usually a low-carbon steel pipe for pressure bearing, and the inner pipe is a medium-high carbon steel for wear resistance. Since the inner pipe is completely hardened, it has high hardness but poor brittleness, and it is easy to fall off during concrete pumping, resulting in pipe bursts and shortening the life of the delivery pipe.

[0007] In addition, according to the analysis of the early failure forms of the conveying pipe, it is found that the failure of the conveying pipe is mainly concentrated in the wear and tear near the pipe mouth. This is because the heat input during the flange welding process is too large, which will reduce the hardness of the inner pipe near the pipe mouth, resulting in a decrease in the wear resistance of the conveying pipe near the pipe mouth. Summary of the invention

[0008] The purpose of the invention is to solve the problems of the prior art that the concrete conveying pipe is easy to explode and has poor wear resistance.

[0009] In order to achieve the above object, the first aspect of the present invention provides a concrete conveying pipe, which comprises an inner pipe, an outer pipe and an intermediate layer arranged in the gap between the inner pipe and the outer pipe, wherein the first material composition forming the intermediate layer contains the following components which are stored independently or in a mixture of two or more thereof:

[0010] Epoxy resin, component A and component B;

[0011] The component A is selected from at least one of ethylenediamine, urea, phenol and tetraethylenepentamine;

[0012] The average particle size of component B is not greater than 30 μm, and the component B is selected from at least one of carbonate, silicate, wollastonite, aluminosilicate, and silicon dioxide;

[0013] Relative to 100 parts by weight of the epoxy resin, the content of the component A is 60-120 parts by weight, and the content of the component B is 140-180 parts by weight.

[0014] A second aspect of the present invention provides a method for preparing the concrete delivery pipe according to the first aspect, the method comprising:

[0015] (1) quenching the inner tube to obtain a quenched inner tube;

[0016] (2) nesting the quenched inner tube and the outer tube to form a double-layer tube with a gap of 0.1-2 mm, and filling the gap of the double-layer tube with a first material composition forming an intermediate layer to obtain a transport tube precursor; controlling the composition of the first material composition and / or the filling method of the first material composition so that the filling rate of the intermediate layer is not less than 75%;

[0017] (3) The delivery pipe precursor is subjected to tempering treatment.

[0018] A third aspect of the present invention provides a concrete pump truck, the concrete pump truck comprising the concrete delivery pipe according to the first aspect.

[0019] The concrete conveying pipe provided by the present invention has a double-layer pipe structure, and an intermediate layer formed of a specific material is arranged between the inner pipe and the outer pipe, which can not only play a bonding and buffering role to prevent the conveying pipe from bursting due to excessive pressure, but also prevent the welding heat from being input from the outer pipe to the inner pipe, prevent the hardness of the inner pipe from decreasing, and improve the wear resistance of the inner pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a front view of the concrete delivery pipe of the present invention;

[0021] Figure 2 yes Figure 1AA section view of the concrete delivery pipe shown;

[0022] Figure 3 It is a schematic diagram of the structure of the negative pressure inhalation device of the present invention;

[0023] Figure 4 It is a structural schematic diagram of a preferred specific implementation method of the negative pressure inhalation method of the present invention.

[0024] Description of Reference Numerals

[0025] 1. Inner tube 2. Middle layer

[0026] 3. Outer tube 4. Flange

[0027] 5. Welding seam 6. Sealant

[0028] 7. Release cloth 8. Vacuum film

[0029] 9. Vacuum nozzle 10. Colloid tank

[0030] 11. First material composition DETAILED DESCRIPTION

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] The following combination Figure 1 , Figure 2 , Figure 3 and Figure 4 The structure shown in the figure describes in detail the preferred specific embodiment of the concrete delivery pipe of the present invention. Figure 2 yes Figure 1 AA cross-sectional view of the concrete delivery pipe is shown.

[0033] As mentioned above, the first aspect of the present invention provides a concrete conveying pipe, which comprises an inner pipe 1, an outer pipe 3, and an intermediate layer 2 arranged in the gap between the inner pipe 1 and the outer pipe 3, wherein the first material composition forming the intermediate layer 2 contains the following components which are stored independently or in a mixture of two or more thereof:

[0034] Epoxy resin, component A and component B;

[0035] The component A is selected from at least one of ethylenediamine, urea, phenol and tetraethylenepentamine;

[0036] The average particle size of component B is not greater than 30 μm, and the component B is selected from at least one of carbonate, silicate, wollastonite, aluminosilicate, and silicon dioxide;

[0037] Relative to 100 parts by weight of the epoxy resin, the content of the component A is 60-120 parts by weight, and the content of the component B is 140-180 parts by weight.

[0038] The concrete delivery pipe of the present invention is a double-layer pipe, and an intermediate layer is arranged between the inner pipe and the outer pipe. The intermediate layer is formed by using specific components according to a proportion, and also has the following effects:

[0039] (1) The intermediate layer of the present invention can play a bonding role to prevent the inner tube from cracking or falling off due to impact.

[0040] (2) The intermediate layer of the present invention can play a buffering role, reduce the impact on the inner tube, and avoid cracking of the inner tube.

[0041] (3) In particular, the intermediate layer formed by compounding the components in a specific ratio in the present invention is a colloid when not solidified, has good fluidity, and can fill the gap between the inner and outer tubes by negative pressure suction without requiring a large pressure difference.

[0042] (4) The present invention adds a specific type of component B to the first material composition forming the intermediate layer, which can ensure that the volume difference of the intermediate layer remains substantially unchanged after the intermediate layer colloid is cured, so that the intermediate layer can completely fill the gap between the inner and outer tubes, while also reducing production costs.

[0043] According to a particularly preferred embodiment of the present invention, the component A is a combination of ethylenediamine and phenol in a weight ratio of 1:0.6-0.9, and the component B is a combination of silicate and wollastonite in a weight ratio of 0.7-1:1. The inventors have found that the use of this preferred embodiment can better play the role of bonding and buffering, improve the wear resistance of the concrete delivery pipe, and thus increase the service life of the concrete delivery pipe.

[0044] Preferably, relative to 100 parts by weight of the epoxy resin, the content of component A is 60-100 parts by weight, and the content of component B is 150-180 parts by weight. The inventors found in the research process that by adopting this preferred embodiment, the first material composition can be better filled in the gap of the double-layer pipe, thereby obtaining a concrete delivery pipe with better performance.

[0045] According to a particularly preferred embodiment of the present invention, the inner tube 1 is a seamless tube of at least one selected from wear-resistant steel, bearing steel, and high-chromium cast iron.

[0046] According to another particularly preferred embodiment of the present invention, the inner tube 1 is a welded tube made of at least one selected from wear-resistant steel, bearing steel, and high-chromium cast iron.

[0047] Preferably, the outer tube 3 is a seamless tube or a welded tube made of low carbon steel.

[0048] Preferably, the concrete conveying pipe further comprises flanges 4 arranged at both ends of the concrete conveying pipe, and the flanges 4 are connected to the outer pipe 3 via welds 5 .

[0049] As mentioned above, the second aspect of the present invention provides a method for preparing the concrete delivery pipe according to the first aspect, the method comprising:

[0050] (1) quenching the inner tube to obtain a quenched inner tube;

[0051] (2) nesting the quenched inner tube and the outer tube to form a double-layer tube with a gap of 0.1-2 mm, and filling the gap of the double-layer tube with a first material composition forming an intermediate layer to obtain a transport tube precursor; controlling the composition of the first material composition and / or the filling method of the first material composition so that the filling rate of the intermediate layer is not less than 75%;

[0052] (3) The delivery pipe precursor is subjected to tempering treatment.

[0053] In the present invention, unless otherwise stated, the method for detecting the filling rate of the intermediate layer is: cut the straight tube evenly into 6 equal parts to obtain 5 cutting surfaces, measure the length L of the gap portion of each cutting surface respectively, take the circumference of the central circle of the intermediate layer ring as the circumference S of the intermediate layer, then the filling rate of a single cross section N = 1-L / S, and the average value of the filling rates of the 5 cutting surfaces is the filling rate of the intermediate layer.

[0054] Preferably, in step (1), the quenching treatment includes a heating stage and a cooling stage.

[0055] Preferably, in step (1), the conditions of the heating stage include at least: a temperature of 800-1000° C. and a time of 2-8 h.

[0056] Preferably, in step (1), the cooling method in the cooling stage is selected from at least one of water cooling, oil cooling and air cooling.

[0057] During the research process, the inventors found that by adopting the method provided by the present invention, the hardness of the quenched inner tube can reach 66-68HRC. Combined with the intermediate layer with bonding effect of the present invention, the hardness of the inner tube after quenching can be improved, while preventing the inner tube from cracking and falling off due to excessive hardness, resulting in a reduced service life.

[0058] According to a particularly preferred embodiment of the present invention, in step (2), a negative pressure suction device is used to fill the first material composition forming the middle layer into the gap of the double-layer tube.

[0059] It should be noted that, in the present invention, the components in the first material composition are first mixed to obtain a mixture with a viscosity of 200-300 mpa·s at 25° C., and then the mixture is filled into the gap of the double-layer tube.

[0060] The present invention has no special requirements on the mixing order and mixing method of the components in the first material composition, as long as a material with good fluidity can be obtained. For example, the present invention can obtain an intermediate layer colloid by contacting and mixing epoxy resin, component A and component B.

[0061] Preferably, the contact mixing conditions at least include: a stirring speed of 30-80 rpm and a time of 1-3 min.

[0062] In order to enable the first material composition to be filled better, the present invention adopts Figure 3 The negative pressure suction device shown introduces the first material composition forming the middle layer into the gap of the double-layer tube in a negative pressure suction manner.

[0063] Preferably, in step (2), the negative pressure suction device includes the double-layer tube and a colloid tank 10 for holding the first material composition 11, one end of the double-layer tube is placed in the colloid tank 10, the other end of the double-layer tube is sealed by a sealing assembly, and the gap of the double-layer tube is connected to the vacuum pump through a pipeline.

[0064] Preferably, in step (2), the sealing assembly includes a sealant 6 arranged on the outer wall of the outer tube 3 and the inner wall of the inner tube 1, a demoulding cloth 7 arranged on the double-layer tube port, and a vacuum film 8 adhered to the upper surface of the sealant 6, and the vacuum film 8 is also provided with a through hole connected to the vacuum suction nozzle 9, and the vacuum suction nozzle 9 is connected to the vacuum pump through a pipeline.

[0065] The following combination Figure 3 and Figure 4 A preferred specific implementation of the negative pressure inhalation specific operation method described in the present invention includes:

[0066] One end of the double-layer tube is placed in a colloid tank 10 containing the first material composition 11, and one end of the double-layer tube is completely immersed in the first material composition 11; then, sealant 6 is evenly applied to the outer wall of the outer tube 3 and the inner wall of the inner tube 1 at the other end of the double-layer tube, and a vacuum film 8 is pasted on the sealant 6. A through hole connected to a vacuum suction nozzle 9 is opened on the surface of the vacuum film 8, and the vacuum suction nozzle 9 is connected to a vacuum pump (not shown in the drawings). Sealant is evenly applied to the connection between the vacuum suction nozzle 9 and the through hole, and a release cloth 7 (gas can pass through the release cloth, but the first material composition forming the middle layer cannot pass through) is laid flat on the surface of the other end of the double-layer tube;

[0067] Then, the vacuum pump is turned on to discharge the gas in the gap of the double-layer tube. At the same time, because of the negative pressure (≤-90 KPa) generated in the gap of the double-layer tube, the first material composition 11 is sucked into the gap.

[0068] The present invention has no special requirements on the types of the sealant, release cloth and vacuum film. Sealant, release cloth and vacuum film known in the art can be used, and those skilled in the art should not understand this as a limitation to the present invention.

[0069] In order to ensure that the colloid completely fills the gap of the double-layer tube, the present invention can also add a rotating device on the outer tube to rotate the double-layer tube during the air extraction process. The present invention has no special requirements for the rotating device, and it can be carried out using equipment known in the art.

[0070] Preferably, in step (2), the composition of the first material composition and / or the filling method of the first material composition are controlled so that the filling rate of the intermediate layer is not less than 90%.

[0071] Preferably, in step (3), the tempering treatment conditions include at least: a temperature of 100-150° C. and a time of 1-5 h.

[0072] Preferably, in step (3), the method further comprises: welding flanges at both ends of the concrete delivery pipe after the tempering treatment.

[0073] The present invention has no special requirements on the specific welding method of the flange, and the flange can be welded by methods known in the art. For example, the present invention adopts argon gas shielded welding to weld the flange.

[0074] It should be noted that the mixture of the components in the first material composition is in a colloidal state, and the mixture solidifies while being tempered. After the mixture solidifies, the volume of the mixture remains substantially unchanged, ensuring that the gap between the inner and outer tubes is completely filled.

[0075] As mentioned above, the third aspect of the present invention provides a concrete pump truck, which comprises the concrete delivery pipe described in the first aspect.

[0076] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, all the raw materials used are commercially available products.

[0077] Epoxy resin: brand JL-220A, purchased from Changshu Jiafa Chemical Co., Ltd.;

[0078] Polyurethane: brand JQ-1 glue, purchased from Liaoning Hongshan Chemical Co., Ltd.;

[0079] Silicate: Calcium silicate;

[0080] Carbonates: calcium carbonate;

[0081] Aluminosilicate: kaolin;

[0082] In the following examples, the ethylenediamine, phenol, urea, silicon dioxide, and tetraethylenepentamine are all analytically pure chemical reagents, the outer tubes are all Q345B welded tubes, and the inner tubes are all Gr20 seamless steel tubes.

[0083] Example 1

[0084] This embodiment provides a method for preparing a concrete delivery pipe, the method comprising:

[0085] (1) quenching the inner tube to obtain a quenched inner tube;

[0086] Among them, the conditions of the heating stage in the quenching treatment are: temperature 850°C, time 5h;

[0087] Air cooling is used in the cooling stage of quenching treatment;

[0088] (2) The quenched inner tube and the outer tube are nested to form a double-layer tube with a gap of 2 mm, and the components in the first material composition are contacted and mixed (stirring speed is 40 rpm, time is 3 min) to obtain a colloidal mixed material (viscosity is 200 mPa·s at 25° C.), and Figure 3 and Figure 4 The method shown is to fill the mixed material into the gap of the double-layer tube to obtain a transport tube precursor;

[0089] Wherein, the first material composition is composed of epoxy resin, ethylenediamine, phenol, silicate and wollastonite in a weight ratio of 100:50:45:70:80;

[0090] (3) subjecting the conveying pipe precursor to tempering treatment, and welding flanges at both ends of the conveying pipe obtained after the tempering treatment by argon gas shielded welding;

[0091] The tempering conditions are as follows: temperature is 120°C and time is 2h.

[0092] Example 2

[0093] This embodiment provides a method for preparing a concrete delivery pipe, the method comprising:

[0094] (1) quenching the inner tube to obtain a quenched inner tube;

[0095] Among them, the conditions of the heating stage in the quenching treatment are: temperature 900°C, time 4h;

[0096] Air cooling is used in the cooling stage of quenching treatment;

[0097] (2) The quenched inner tube and the outer tube are nested to form a double-layer tube with a gap of 1 mm, and the components in the first material composition are contacted and mixed (stirring speed is 50 rpm, time is 2 min) to obtain a colloidal mixed material (viscosity is 250 mPa·s at 25° C.), and Figure 3 and Figure 4 The method shown is to fill the mixed material into the gap of the double-layer tube to obtain a transport tube precursor;

[0098] Wherein, the first material composition is composed of epoxy resin, ethylenediamine and wollastonite in a weight ratio of 100:80:160;

[0099] (3) subjecting the conveying pipe precursor to tempering treatment, and welding flanges at both ends of the conveying pipe obtained after the tempering treatment by argon gas shielded welding;

[0100] The tempering conditions are as follows: temperature is 130°C and time is 1.5h.

[0101] Example 3

[0102] This embodiment provides a method for preparing a concrete delivery pipe, the method comprising:

[0103] (1) quenching the inner tube to obtain a quenched inner tube;

[0104] Among them, the conditions of the heating stage in the quenching treatment are: temperature 800°C, time 7h;

[0105] Air cooling is used in the cooling stage of quenching treatment;

[0106] (2) The quenched inner tube and the outer tube are nested to form a double-layer tube with a gap of 2 mm, and the components in the first material composition are contacted and mixed (stirring speed is 50 rpm, time is 1 min) to obtain a colloidal mixed material (viscosity is 300 mPa·s at 25° C.), and Figure 3 and Figure 4 The method shown is to fill the mixed material into the gap of the double-layer tube to obtain a transport tube precursor;

[0107] The first material composition is composed of epoxy resin, tetraethylenepentamine, and silicon dioxide in a weight ratio of 100:100:180;

[0108] (3) subjecting the conveying pipe precursor to tempering treatment, and welding flanges at both ends of the conveying pipe obtained after the tempering treatment by argon gas shielded welding;

[0109] The tempering conditions are as follows: temperature is 150°C and time is 3h.

[0110] Example 4

[0111] A concrete delivery pipe was prepared according to the method of Example 1, except that in step (2), the first material composition consisted of epoxy resin, urea, phenol, silicate and wollastonite in a weight ratio of 100:50:45:70:80.

[0112] Example 5

[0113] A concrete delivery pipe was prepared according to the method of Example 1, except that in step (2), the first material composition consisted of epoxy resin, ethylenediamine, phenol, silicate and wollastonite in a weight ratio of 100:65:65:70:80.

[0114] Example 6

[0115] A concrete delivery pipe was prepared according to the method of Example 1, except that in step (2), the first material composition consisted of epoxy resin, ethylenediamine, phenol, silicate and wollastonite in a weight ratio of 100:50:45:40:80.

[0116] Example 7

[0117] A concrete delivery pipe was prepared according to the method of Example 1, except that in step (2), the first material composition consisted of epoxy resin, ethylenediamine, phenol, aluminosilicate and wollastonite in a weight ratio of 100:50:45:70:80.

[0118] Comparative Example 1

[0119] A concrete delivery pipe was prepared according to the method of Example 1, except that the middle layer was not filled;

[0120] The specific operation methods include:

[0121] (1) quenching the inner tube to obtain a quenched inner tube;

[0122] Among them, the conditions of the heating stage in the quenching treatment are: temperature 850°C, time 5h;

[0123] Air cooling is used in the cooling stage of quenching treatment;

[0124] (2) nesting the quenched inner tube and the outer tube to form a double-layer tube with a gap of 2 mm, and tempering the double-layer tube;

[0125] The tempering conditions are as follows: temperature is 120°C and time is 2h.

[0126] Comparative Example 2

[0127] A concrete delivery pipe was prepared according to the method of Example 1, except that in step (2), the first material composition consisted of epoxy resin, ethylenediamine, phenol, silicate and wollastonite in a weight ratio of 100:70:60:70:80.

[0128] Comparative Example 3

[0129] A concrete delivery pipe was prepared according to the method of Example 1, except that in step (2), the first material composition consisted of epoxy resin, ethylenediamine, phenol, silicate and wollastonite in a weight ratio of 100:50:45:70:50.

[0130] Comparative Example 4

[0131] A concrete delivery pipe was prepared according to the method of Example 1, except that in step (2), an equal weight of polyurethane was used to replace the epoxy resin in the first material composition.

[0132] Test Case

[0133] The concrete delivery pipes prepared in the examples and comparative examples were subjected to performance tests, and the specific test results are shown in Table 1.

[0134] Among them, the hardness of the inner tube is tested by Rockwell hardness tester, and the specific testing method refers to GB / T230.1-2018;

[0135] The service life is assessed through loading, and the cumulative volume of concrete pumped when the concrete delivery pipe fails is taken as the service life of the delivery pipe.

[0136] Table 1

[0137]

[0138]

[0139] It can be seen from the results in Table 1 that the present invention provides an intermediate layer between the inner pipe and the outer pipe, which can not only play a bonding and buffering role to effectively avoid the bursting of the conveying pipe, but also improve the wear resistance of the inner pipe, thereby obtaining a concrete conveying pipe with a longer service life.

[0140] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A concrete delivery pipe, characterized in that: The concrete conveying pipe comprises an inner pipe (1), an outer pipe (3), and an intermediate layer (2) arranged in a gap between the inner pipe (1) and the outer pipe (3) in a double-layer pipe, wherein the first material composition forming the intermediate layer (2) contains the following components which are stored independently or in a mixture of two or more thereof: Epoxy resin, component A and component B; The component A is selected from at least one of ethylenediamine, urea, a combination of ethylenediamine and phenol, and tetraethylenepentamine; The average particle size of component B is not greater than 30 μm, and component B is selected from at least one of carbonate, silicate, wollastonite, aluminosilicate, and silicon dioxide; Relative to 100 parts by weight of the epoxy resin, the content of the component A is 60-120 parts by weight, and the content of the component B is 140-180 parts by weight.

2. The concrete delivery pipe according to claim 1, wherein: The component A is a combination of ethylenediamine and phenol in a weight ratio of 1:0.6-0.9, and the component B is a combination of silicate and wollastonite in a weight ratio of 0.7-1:

1.

3. The concrete delivery pipe according to claim 2, wherein: Relative to 100 parts by weight of the epoxy resin, the content of the component A is 60-100 parts by weight, and the content of the component B is 150-180 parts by weight.

4. The concrete delivery pipe according to claim 1, wherein: The inner tube (1) is a seamless tube made of at least one selected from wear-resistant steel, bearing steel, and high-chromium cast iron; or The inner tube (1) is a welded tube made of at least one selected from wear-resistant steel, bearing steel, and high-chromium cast iron.

5. The concrete delivery pipe according to any one of claims 1 to 4, wherein: The outer tube (3) is a seamless tube or a welded tube made of low carbon steel.

6. The concrete delivery pipe according to any one of claims 1 to 5, wherein: The concrete conveying pipe further comprises flanges (4) arranged at both ends of the concrete conveying pipe, and the flanges (4) are connected to the outer pipe (3) via a weld (5).

7. A method for preparing the concrete delivery pipe according to any one of claims 1 to 6, characterized in that: The method includes: (1) quenching the inner tube to obtain a quenched inner tube; (2) nesting the quenched inner tube and the outer tube to form a double-layer tube with a gap of 0.1-2 mm, and filling the gap of the double-layer tube with a first material composition forming an intermediate layer to obtain a transport tube precursor; controlling the composition of the first material composition and / or the filling method of the first material composition so that the filling rate of the intermediate layer is not less than 75%; (3) The delivery pipe precursor is subjected to tempering treatment.

8. The method according to claim 7, wherein: In step (1), the quenching treatment includes a heating stage and a cooling stage; and / or In step (1), the conditions of the heating stage include at least: a temperature of 800-1000°C and a time of 2-8 hours; and / or In step (1), the cooling method in the cooling stage is selected from at least one of water cooling, oil cooling, and air cooling.

9. The method according to claim 7 or 8, wherein: In step (2), a negative pressure suction device is used to fill the first material composition forming the middle layer into the gap of the double-layer tube.

10. The method according to claim 9, wherein: The negative pressure suction device comprises the double-layer tube and a colloid tank (10) for containing the first material composition (11); one end of the double-layer tube is placed in the colloid tank (10); the other end of the double-layer tube is sealed by a sealing component; and the gap of the double-layer tube is connected to a vacuum pump via a pipeline.

11. The method according to claim 10, wherein: The sealing assembly comprises a sealant (6) arranged on the outer wall of the outer tube (3) and the inner wall of the quenched inner tube, a demoulding cloth (7) arranged on the port of the double-layer tube, and a vacuum film (8) adhered to the upper surface of the sealant (6); the vacuum film (8) is also provided with a through hole connected to a vacuum suction nozzle (9); the vacuum suction nozzle (9) is connected to the vacuum pump through a pipeline.

12. The method according to any one of claims 7 to 11, wherein: In step (2), the composition of the first material composition and / or the filling method of the first material composition are controlled so that the filling rate of the intermediate layer is not less than 90%.

13. The method according to any one of claims 7 to 12, wherein: In step (3), the tempering treatment conditions include at least: a temperature of 100-150° C. and a time of 1-5 h.

14. The method according to any one of claims 7 to 13, wherein: In step (3), the method further includes: welding flanges at both ends of the concrete delivery pipe after the tempering treatment.

15. A concrete pump truck, characterized in that: The concrete pump truck comprises the concrete delivery pipe according to any one of claims 1-6.

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