A composite tail gas pipeline system and its forming method

Abstract

The present invention relates to the technical field of industrial pipeline design and manufacturing, and particularly relates to a composite exhaust gas pipeline system and a forming method thereof. The system includes an exhaust gas pipeline unit and a connection unit arranged at the axial end of the exhaust gas pipeline unit; the exhaust gas pipeline unit includes an inner side wall plate, a radial filling structure and an outer side wall plate which are arranged in sequence from the inside to the outside; a radial support structure is further arranged between the radial filling structure and the outer side wall plate; a second transition buffer structure is further arranged between the radial support structure, the radial filling structure and the outer side wall plate. Compared with the prior art, the present invention optimizes the pipeline connection process and can achieve connection without heating; at the same time, it improves the heat insulation and pipeline strength, effectively buffers the damage caused by different thermal expansion rates caused by the temperature difference between the inside and outside of the pipeline, and greatly improves the service life.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial pipeline design and manufacturing, and particularly to a composite tail gas pipeline system and a forming method thereof. Background Art

[0002] The tail gas pipeline is often used as a common transportation pipeline for high-temperature gases or tail gases. Especially for the transportation of tail gases used in industrial waste heat recovery, it is necessary to play a heat preservation role during transportation, and at the same time meet the requirements of high strength and light weight at high temperatures. In traditional technologies, metal structure pipelines have problems such as large weight, welding deformation, and easy corrosion. Existing composite material pipelines have problems such as poor rigidity, large weight and volume, poor heat insulation and heat prevention ability, easy cracking of materials between different layers, short service life, non-reusability, and difficulty in balancing heat insulation, volume and connection.

[0003] Therefore, the demand for developing a set of high-temperature gas or tail gas pipelines that are lightweight, have good high-temperature mechanical strength, good heat insulation performance, are easy to connect and have a long service life is particularly urgent. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a composite tail gas pipeline system and a forming method thereof to solve at least one of the technical problems of low high-temperature mechanical strength, poor heat insulation performance and short service life existing in the existing tail gas pipelines.

[0005] The object of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention provides a composite tail gas pipeline system, which includes a tail gas pipeline unit and a connection unit arranged at the axial end of the tail gas pipeline unit for fixed connection of the tail gas pipeline unit; the tail gas pipeline unit includes an inner side wall plate, a radial filling structure and an outer side wall plate arranged in sequence from the inside to the outside; a radial support structure is further arranged between the radial filling structure and the outer side wall plate; a second transition buffer structure is further arranged between the radial support structure, the radial filling structure and the outer side wall plate; the radial support structure and the outer side wall plate are fixedly connected through the second transition buffer structure; the radial filling structure and the outer side wall plate are fixedly connected through the second transition buffer structure;

[0007] The second transition buffer structure is a multi-layer composite structure including a toughness support layer, and the toughness support layer can match the radial support structure and the outer side wall plate with different thermal expansion coefficients, and the toughness support layer can match the radial filling structure and the outer side wall plate with different thermal expansion coefficients.

[0008] Preferably, the difference in thermal expansion coefficient between the radial support structure or the radial filling structure and the outer side wall plate is 35×10 -6 m / ℃~41×10-6 m / °C.

[0009] Preferably, the second transition buffer structure includes a third rigid connection layer, a second toughness support layer, and a fourth rigid connection layer that are sequentially distributed from the high-temperature region to the low-temperature region.

[0010] Preferably, the third rigid connection layer is a fiberglass mat layer, the second toughness support layer is a fiberglass cloth layer, and the fourth rigid connection layer is a fiberglass mat layer.

[0011] Preferably, the fiberglass mat layer of the third rigid connection layer is 2 to 3 layers, the fiberglass cloth layer of the second toughness support layer is 1 to 3 layers, and the fiberglass mat layer of the fourth rigid connection layer is 2 to 3 layers.

[0012] Preferably, the fiberglass mats of the third rigid connection layer and the fourth rigid connection layer have a fiber length of 10 mm to 15 mm; the fiberglass mats are chopped strands; the fiberglass cloth is any one of twill cloth, serge cloth, and plain cloth; the density of the fiberglass cloth is 170 g / cm 3 ~220 g / cm 3 Serge cloth.

[0013] Preferably, the connection unit is provided with a fixed connection layer and a housing for fastening the tail gas pipeline unit from the inside to the outside; the housing is provided with a glue injection hole.

[0014] Preferably, a sealing structure is provided along the outer wall of the tail gas pipeline unit at the end where the housing is close to the tail gas pipeline unit, for preventing the glue liquid of the fixed connection layer from overflowing before curing.

[0015] The fixed connection layer can be prepared after the resin is cured. The resin is one or more of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, photosensitive acrylate resin, and epoxy resin, or modified resins of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, photosensitive acrylate resin, and epoxy resin.

[0016] Preferably, the housing is made of a transparent material; the resin is a photosensitive acrylate resin.

[0017] The sealing structure adopts any one of fluororubber and silicone rubber materials.

[0018] Preferably, a heat insulation prevention layer is further provided inside the inner side wall plate, and the heat insulation prevention layer is fixedly connected to the inner side wall plate through a first transition buffer structure.

[0019] The first transition buffer structure is a multi-layer composite structure including a toughness support layer, and the toughness support layer can match the heat insulation prevention layer and the inner side wall plate with different thermal expansion coefficients.

[0020] Preferably, the difference in the coefficient of thermal expansion between the heat insulation layer and the inner side wall panel is 8×10 -6 m / ℃ to 9×10 -6 m / ℃.

[0021] Preferably, the first transition buffer structure includes a first rigid connection layer, a first ductile support layer, and a second rigid connection layer that are sequentially distributed from the high-temperature region to the low-temperature region.

[0022] Preferably, the first rigid connection layer is a fiberglass mat layer, the first ductile support layer is a fiberglass cloth layer, and the second rigid connection layer is a fiberglass mat layer.

[0023] Preferably, the fiberglass mat layer of the first rigid connection layer is 2 to 3 layers, the fiberglass cloth layer of the first ductile support layer is 1 to 3 layers, and the fiberglass mat layer of the second rigid connection layer is 2 to 3 layers.

[0024] Preferably, the fiberglass of the first rigid connection layer and the second rigid connection layer has a fiber length of 2 mm to 10 mm; the fiberglass mat is chopped strand; the fiberglass cloth is any one of twill cloth, serge cloth, and plain cloth; the density of the fiberglass cloth is 170 g / cm 3 ~220 g / cm 3 Serge cloth.

[0025] Preferably, the tail gas pipeline is further provided with an axial support structure parallel to the axial direction of the tail gas pipeline, and the axial support structure is disposed inside the radial filling structure and fixed to the outer wall of the inner side wall panel.

[0026] Preferably, there are a plurality of the axial support structures, which are circumferentially spaced along the tail gas pipeline.

[0027] Preferably, the axial support structure includes an internal filling structure and an external reinforcement structure surrounding the internal filling structure; the external reinforcement structure includes a panel fixedly connected to the inner side wall panel and a reinforcing rib surrounding and fixing the internal filling structure.

[0028] Preferably, the panel and the reinforcing rib are fiber-reinforced resin matrix structures, the fiber-reinforced resin matrix structures.

[0029] Preferably, the fiber-reinforced structure layer in the axial support structure is quasi-isotropic; the reinforcing fibers of the fiber-reinforced structure layer are one or more of quartz fibers, carbon fibers, high-silica fibers, and basalt fibers.

[0030] Preferably, the reinforcing fiber of the fiber-reinforced resin matrix structure is a carbon fiber.

[0031] Preferably, the matrix resin of the fiber-reinforced resin matrix structure is one or more of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin, or modified resins of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin; the internal filling structure is a lightweight material with a hollow microporous or bubble structure.

[0032] Preferably, the internal filling structure is one or a combination of PEI foam and PMI foam; the matrix resin of the fiber-reinforced resin matrix structure is EH301 epoxy resin.

[0033] Preferably, the tail gas pipeline is further provided with a radial support structure, and the radial support structure is arranged between the radial filling structure and the outer side wall plate.

[0034] Preferably, the radial support structures are arranged at intervals along the axial direction of the tail gas pipeline.

[0035] Preferably, the radial support structure is a lightweight material with a hollow microporous or bubble structure.

[0036] Preferably, the radial support structure is one or a combination of PEI foam and PMI foam.

[0037] Preferably, the thermal insulation layer adopts a fiber-reinforced resin matrix structure.

[0038] Preferably, the matrix resin of the fiber-reinforced resin matrix structure is one or more of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, or modified resins of phenolic resin, silicone resin, silicon-containing arylacetylene resin, and arylacetylene resin.

[0039] Preferably, the matrix resin of the fiber-reinforced resin matrix structure is an interpenetrating phase composite modified phenolic resin.

[0040] Preferably, the fiber-reinforced resin matrix structure is provided with a fiber reinforcement structure layer.

[0041] Preferably, the fiber reinforcement structure layer adopts one or several of a fiber braided structure layer, a fiber cloth laminated paving layer, a chopped strand mat layer, a chopped strand mat needle punching layer, and a fabric laminated needle punching layer.

[0042] Preferably, the reinforcing fibers of the fiber reinforcement structure layer are one or more of quartz fiber, carbon fiber, high silica fiber, and basalt fiber.

[0043] Preferably, the reinforcing fibers of the fiber-reinforced resin matrix structure are quartz fiber, carbon fiber, or a mixture of the two.

[0044] Preferably, the inner side wall panel and the outer side wall panel are of a fiber-reinforced resin matrix structure, and the fiber-reinforced resin matrix structure is provided with a fiber-reinforced structure layer.

[0045] Preferably, the reinforcing fibers of the fiber-reinforced structure layer are one or more of quartz fibers, carbon fibers, high silica fibers, and basalt fibers.

[0046] Preferably, the reinforcing fibers of the fiber-reinforced resin matrix structure are carbon fibers.

[0047] Preferably, the matrix resin of the fiber-reinforced resin matrix structure is one or more of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin, or modified resins of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin.

[0048] Preferably, the matrix resin of the fiber-reinforced resin matrix structure is EH301 epoxy resin.

[0049] Preferably, the radial filling structure is a lightweight material with a hollow microporous or bubble structure.

[0050] Preferably, the radial filling structure is one of PEI foam or PMI foam or a combination of the two.

[0051] The present invention provides a molding method for a composite exhaust gas pipeline system, including the following steps:

[0052] Step 1: Impregnation molding of the thermal insulation layer:

[0053] Prepare the thermal insulation layer in a mold by using a vacuum impregnation process;

[0054] Step 2: Laying the first transition buffer structure:

[0055] Using the outer surface of the thermal insulation layer as a reference surface, lay the raw materials of each layer of the first transition buffer structure layer by layer;

[0056] Step 3: Vacuum infusion molding of the inner side wall panel:

[0057] Using the outer surface of the first transition buffer structure as a reference surface, prepare a preform of the exhaust gas pipeline with the inner side wall panel fixed on the outside by using a vacuum infusion process;

[0058] Step 4: Molding of the axial support structure:

[0059] Prepare the axial support structure in a mold by using an autoclave process;

[0060] Step 5: Assembling the inner side wall panel and the axial support structure:

[0061] Fix and connect the axial support structure at the preset position on the inner side wall panel to obtain a prefabricated exhaust pipe assembly with the axial support structure covered;

[0062] Step 6: Fix the radial filling structure and the radial support structure:

[0063] Bond and fix the radial filling structure on the outer wall of the prefabricated exhaust pipe assembly with the axial support structure covered; bond and fix the radial support structure on the outer wall of the radial filling structure, and cure and form under vacuum to obtain a prefabricated exhaust pipe assembly with the radial filling structure and the radial support structure;

[0064] Step 7: Lay the second transition buffer structure:

[0065] Lay the second transition buffer structure on the outer wall of the prefabricated exhaust pipe assembly with the radial filling structure;

[0066] Step 8: Form the outer side wall panel:

[0067] Prepare the outer side wall panel on the outer wall of the second transition buffer structure by using the vacuum infusion process;

[0068] Step 9: Three-proof coating:

[0069] Brush the three-proof paint on the surface of the cylindrical prefabricated part after the preparation of the outer side wall panel as the external coating;

[0070] Step 10: Connect the exhaust pipe units:

[0071] Take two exhaust pipe units and install the connection unit at the end of the exhaust pipe unit.

[0072] Preferably, in step 1, during the forming process, the vacuum degree ≥ 980 mbar, the heating temperature is 80 °C to 180 °C, and the forming time is 12 h to 24 h.

[0073] Preferably, step 3 includes the following steps:

[0074] Step 3.1: Evacuate the inner side wall panel preform and preheat it at 120 °C to 130 °C, and gradually increase it within the range of 600 mbar to 980 mbar after the negative pressure pumping operation starts;

[0075] Step 3.2: Preheat the resin at 100 °C to 120 °C and then introduce it into the preheated inner side wall panel preform;

[0076] Step 3.3: Heat-treat and form the inner side wall panel preform into which the resin has been introduced at 130 °C to 150 °C and 170 °C to 180 °C in sequence.

[0077] Preferably, step 4 includes the following steps:

[0078] Step 4.1: Use fiber prepreg to cast the panel of the external reinforcement structure in the mold. Vacuum compaction is carried out once every 3 - 5 layers of fiber prepreg paving, with the compaction time being 15 min - 50 min, and the negative pressure operation gradually increases within the range of 600 mbar - 980 mbar after it starts;

[0079] Step 4.2: At the position of the panel for positioning the internal filling structure, lay fiber prepreg layer by layer to prepare the reinforcing rib, and carry out pre-compaction treatment by means of thermal compaction, with the compaction temperature being 130°C - 140°C and the time being 15 min - 50 min;

[0080] Step 4.3: Place the preform with the reinforcing rib 2032 in a vacuum bag in an autoclave, and carry out heat treatment molding in two stages at 130°C - 150°C and 170°C - 180°C successively under the pressure of 0.4 MPa - 0.6 MPa.

[0081] Preferably, the said Step 5 includes the following steps: Fasten and connect the axial support structure and the exhaust pipe preform with the inner side wall panel fixed externally with an adhesive film, and carry out heat treatment molding in two stages at 130°C - 150°C and 170°C - 180°C successively under the negative pressure environment that gradually increases within the range of 600 - 980 mbar.

[0082] Preferably, the said Step 6 includes the following steps:

[0083] Step 6.1: Fix the radial filling structure on the outer wall of the inner side wall panel of the exhaust pipe preform covered with the axial support structure, and position and fixedly connect the radial support structure on the outer wall of the radial filling structure;

[0084] Step 6.2: Carry out heat treatment molding in two stages at 130°C - 150°C and 170°C - 180°C successively for the exhaust pipe preform with the radial filling structure and the radial support structure under the negative pressure environment that gradually increases within the range of 600 - 980 mbar.

[0085] Preferably, in the said Step 8, when using the vacuum infusion process to prepare the outer side wall panel, a release cloth, an isolation film, a flow guiding net and a vacuum bag need to be laid successively on the outer wall of the second transition buffer structure.

[0086] Preferably, at the fillet at the fixed end connection of the outer side wall panel and the radial support structure, a conforming rubber is placed between the vacuum bag and the flow guiding net; and when laying the release cloth at the fillet, two independent release cloths need to be overlapped for treatment, and when laying the flow guiding net at the fillet, two independent flow guiding nets need to be overlapped for treatment.

[0087] Preferably, the said Step 10 includes the following steps:

[0088] Step 10.1: Install and position at both ends of the two exhaust pipe units in the housing;

[0089] Step 10.2: Inject resin into the outer shell for curing and forming.

[0090] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0091] (1) In the present invention, the connecting unit adopts the process of injecting glue and forming at the connection of the tail gas pipeline unit, which can achieve good strength and sealing performance; a transparent material outer shell is used for the connecting unit, and a photosensitive acrylate resin is used to prepare the fixed connection layer, realizing ultraviolet curing without heating, making the connection of the tail gas pipeline unit more convenient; the sealing structure adopts any one of fluororubber and silicone rubber materials, which can play a good sealing role even at a relatively high temperature.

[0092] (2) In the present invention, a transition buffer structure, such as glass fiber felt + glass fiber cloth + glass fiber felt, is arranged between the inner side wall plate and the heat insulation layer. Compared with the prior art, the shear strength of the inner side wall is increased from 55 MPa to 60 MPa, and the shear strength of the outer side wall is increased from 60 MPa to 70 MPa, with increases of 9.09% and 16.6% respectively.

[0093] (3) The transition buffer structure can adopt the structure form of "glass fiber felt + glass fiber cloth + glass fiber felt". The glass fiber cloth layer can produce a certain degree of "creep deformation" when subjected to external force. Its flexible structure greatly improves the stress difference and cracking caused by different thermal expansion coefficients of different materials during temperature change, and forms a good stress buffer layer as a whole; a transition buffer structure can also be arranged at the connection between the radial support structure and the outer side wall plate. Through the close fixed connection between the radial support structure and the glass fiber felt adjacent to the outer side wall plate, the defects of the glass fiber cloth body with weak strength and poor shear resistance can be effectively avoided; furthermore, it can effectively buffer the stress and deformation caused by different material thermal expansion rates due to the temperature difference between the inner and outer sides of the inner side wall plate, and can effectively avoid the cracking and deformation of the inner and outer sides of the inner side wall plate, greatly improving the service life.

[0094] (4) In the present invention, an axial support structure is provided axially in the tail gas pipeline, and a circumferentially distributed radial support structure. The inside of the axial support structure and the radial support structure is light-weighted, which greatly reduces the additional weight brought by the support structure while improving the structural strength, having the advantage of light weight; at the same time, when processing the heat insulation layer, the inner and outer side wall plates, a vacuum impregnation or vacuum infusion process can be adopted to arrange the axial support structure and the radial support structure inside the inner side of the outer wall of the tail gas pipeline, realizing the overall unity of appearance. At the same time, when this structure is subjected to external force, it helps to disperse the external force and the force is more balanced, which can reduce the probability of damage to the tail gas pipeline due to external force.

[0095] (5) The axial support structure, radial support structure, and radial filling structure of the present invention can adopt high-temperature resistant PEI or PMI high-temperature resistant sponge. While achieving lightweight heat insulation, even at high temperatures, the PEI or PMI high-temperature resistant sponge itself still has good strength.

[0096] (6) When forming the outer side wall plate of the present invention, the diversion net at the connection fillet of the radial filling structure and the radial support structure can be overlapped, and a conforming rubber can be placed between the fillet and the vacuum bag, which can improve the defect that the vacuum bag has difficulty in fitting at the connection fillet and the degassing is not complete due to small pressure in the traditional process, and solve the problem of glue accumulation at the fillet.

[0097] (7) The heat insulation and anti-heat layer of the present invention can adopt an interpenetrating phase composite material (IPC), which can be ceramized on the surface at high temperatures, become hard, and has a uniform nanoporous structure, having good heat insulation performance; compared with the high-temperature resistant resin in the prior art, the heat insulation performance is greatly improved, and the thermal conductivity is reduced from 0.078 W / (mK) to 0.066 W / (mK), a decrease of 15.4%.

[0098] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination schemes. Other features and advantages of the present invention will be described in the subsequent specification, and some advantages can be made obvious from the specification, or understood by implementing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the embodiments of the specification and the content specifically pointed out in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation to the present invention. Throughout the drawings, the same reference signs represent the same components.

[0100] Figure 1 It is a schematic cross-sectional view of a composite tail gas pipeline system in an embodiment of the present invention;

[0101] Figure 2 It is a schematic diagram of the state without glue accumulation at the connection fillet of the outer side wall plate and the radial support structure in an embodiment of the present invention;

[0102] Figure 3 It is a schematic diagram of the state with glue accumulation at the connection fillet of the outer side wall plate and the radial support structure in an embodiment of the present invention;

[0103] Figure 4 It is a schematic diagram of the process layout of vacuum impregnation and vacuum infusion in an embodiment of the present invention;

[0104] Figure 5 It is a schematic diagram of the internal structure of the axial support structure in an embodiment of the present invention;

[0105] Figure 6 Schematic diagram of the laying of each layer of the carbon fiber fabric prepreg in an embodiment of the present invention;

[0106] Figure 7 Schematic diagram of the first transition buffer structure in an embodiment of the present invention;

[0107] Figure 8 Side view of the composite tail gas pipeline system in an embodiment of the present invention;

[0108] Figure 9a is Figure 8 Cross-sectional view taken along the plane A1 - A1 of

[0109] Figure 9b is Figure 8 Cross-sectional view taken along the plane A2 - A2 of

[0110] Figure 10a is Figure 9a and Figure 9b Cross-sectional view taken along the plane B1 - B1 in

[0111] Figure 10b is Figure 9a and Figure 9b Cross-sectional view taken along the plane B2 - B2 in

[0112] Figure 11 CT image of the connection between the inner side wall panel and the heat insulation and protection panel in Example 4;

[0113] Figure 12 CT image of the connection between the inner side wall panel and the heat insulation and protection panel in Comparative Example 2;

[0114] Figure 13 Finished product picture of the outer side wall panel formed with conformal rubber in Example 4;

[0115] Figure 14 Finished product picture of the outer side wall panel not formed with conformal rubber in Comparative Example 3;

[0116] Figure 15 Schematic diagram of the second transition buffer structure in an embodiment of the present invention;

[0117] Figure 16 Schematic diagram of the structure of the composite tail gas pipeline system in an embodiment of the present invention.

[0118] Reference numerals:

[0119] Heat insulation layer 1; Axial support structure 2; Internal filling structure 202; External reinforcement structure 203; Panel 2031; Reinforcing rib 2032; Inner side wall panel 3; Radial filling structure 4; Outer side wall panel 5; Radial support structure 6; External coating 7; External coating main body 701; Annular protrusion 702; First transition buffer structure 8; First rigid connection layer 801; First toughness support layer 802; Second rigid connection layer 803; 9 Carbon fiber fabric prepreg; Layer 901 rotated 90° relative to the bottom carbon fiber fabric prepreg layer; Bottom carbon fiber fabric prepreg layer 902; Layer 903 rotated 45° counterclockwise relative to the bottom carbon fiber fabric prepreg layer; Layer 904 rotated 45° clockwise relative to the bottom carbon fiber fabric prepreg layer; Second transition buffer structure 10; Third rigid connection layer 1001; Second toughness support layer 1002; Fourth rigid connection layer 1003; Outer side wall panel external glue accumulation and special-shaped area 11; Preform to be formed 12; Vacuum bag 13; Autoclave 14; Autoclave air inlet and outlet 1401; Mold 15; Vacuum extraction port 16; Connection unit 17; Fixed connection layer 1702; Outer shell 1701; Sealing structure 1703; Glue injection hole 1704; Tail gas pipeline unit 18. Detailed implementation mode

[0120] The following will specifically describe the preferred embodiments of the present invention in conjunction with the accompanying drawings. Among them, the accompanying drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principle of the present invention, rather than to limit the scope of the present invention.

[0121] In order to clearly express the technical solution of the present invention, the following terms are specifically explained:

[0122] Three-proof paint: After curing, it forms a transparent protective film with excellent insulation, moisture-proof, anti-electric leakage, shock-proof, dust-proof, anti-corrosion, anti-aging, corona resistance and other properties.

[0123] Quasi-isotropic: A symmetric laminated plate with the same stiffness in all in-plane directions and no tension-shear or shear-tension coupling effect. The difference from an isotropic laminated plate is that the stiffness in the thickness direction is not necessarily the same as the in-plane stiffness; its bending stiffness performance is not isotropic either.

[0124] Chopped strand mat: A glass fiber fabric formed by randomly distributing and bonding short-cut glass fiber filaments after cutting.

[0125] Laminated laying of fiber cloth: Laying multiple layers of fiber cloth.

[0126] Needling form of chopped strand mat, needling of fabric laminate: Needling the combed chopped strand mat in a needling form and the fabric laminate, and using a mechanical method to entangle the fibers with each other to reinforce the fiber web to form a felt-like material.

[0127] Fiberglass cloth refers to various fiberglass cloths and fiberglass fabrics woven from fiberglass yarns.

[0128] Release cloth: Release cloth is a process auxiliary material in the process of forming and curing composite components. It is also a material placed between the mold and the blank part to prevent the resin from sticking to the mold.

[0129] Equalizing plate: The equalizing plate is a process auxiliary material in the process of forming and curing composite components. It is also a material placed between the mold and the blank part to prevent the blank part from being unevenly pressured.

[0130] Perforated separator film: In the autoclave molding process, it mainly plays a role in positioning and fixing. It is an auxiliary material that allows volatile components to pass through and can absorb a certain amount of excess resin; for processes with less resin content, such as prepreg vacuum molding, a non-perforated separator film is mostly selected.

[0131] Breather felt: It has good absorption performance. It can absorb extra resin or act as a medium in the vacuum process.

[0132] Flow net: It is a net-like structure used in the vacuum process when using resin to promote the flow of resin and quickly and effectively disperse the resin throughout the part.

[0133] Form-following rubber: An uncured rubber material that can freely deform under pressure without actively rebounding.

[0134] Vacuum impregnation process: It is a vacuum application process in which, under vacuum conditions, the impregnating material is impregnated into other solid substances through negative pressure to improve the material properties of the substance or meet certain specific requirements.

[0135] Vacuum infusion process: It refers to laying fiberglass, fiberglass fabric, various inserts, release cloth, resin penetration layer, laying resin pipelines and covering nylon and flexible film (vacuum bag) on the cured gel coat layer; the film and the molding chamber are sealed, evacuated, and the resin flows along the resin pipelines and other components to impregnate the fibers and further cure and form.

[0136] On the one hand, the present invention provides a composite tail gas pipeline system, as Figure 16 shown, comprising a tail gas pipeline unit 18 and a connection unit 17 arranged at the axial end of the tail gas pipeline unit for fixedly connecting the tail gas pipeline unit.

[0137] As Figure 1As shown, the tail gas pipeline unit includes: an inner side wall plate 3, a radial filling structure 4, and an outer side wall plate 5 arranged in sequence from inside to outside; a radial support structure 6 is further provided between the radial filling structure 4 and the outer side wall plate 5; a second transition buffer structure 10 is further provided between the radial support structure 6, the radial filling structure 4 and the outer side wall plate 5; the radial support structure 6 and the outer side wall plate 5 are fixedly connected through the second transition buffer structure 10; the radial filling structure 4 and the outer side wall plate 5 are fixedly connected through the second transition buffer structure 10;

[0138] The second transition buffer structure 10 is a multi-layer composite structure including a toughness support layer, and the toughness support layer can match the radial support structure 6 and the outer side wall plate 5 with different thermal expansion coefficients, and, the toughness support layer can match the radial filling structure 4 and the outer side wall plate 5 with different thermal expansion coefficients.

[0139] Preferably, the connection unit 17 is provided with a fixed connection layer 1702 and a housing 1701 for fastening the tail gas pipeline unit from inside to outside; a glue injection hole 1704 is provided on the housing.

[0140] Preferably, a sealing structure 1703 is provided along the outer wall of the tail gas pipeline unit at the end where the housing abuts against the tail gas pipeline unit, for preventing the glue liquid of the fixed connection layer from overflowing before curing.

[0141] The fixed connection layer 1702 can be prepared by curing resin, and the resin is one or more of phenolic resin, silicone resin, silicon-containing aryl acetylene resin, aryl acetylene resin, photosensitive acrylate resin and epoxy resin or modified resins of phenolic resin, silicone resin, silicon-containing aryl acetylene resin, aryl acetylene resin, photosensitive acrylate resin and epoxy resin.

[0142] Preferably, the housing 1701 is made of a transparent material; the resin is a photosensitive acrylate resin.

[0143] The sealing structure 1703 is made of any one of fluororubber and silicone rubber materials.

[0144] Compared with the prior art, the present invention adopts an injection molding process of injecting glue at the connection of the tail gas pipeline unit for the connection unit 13, and can achieve good strength and sealing performance.

[0145] Using a transparent material housing and using a photosensitive acrylate resin to prepare the fixed connection layer 1702, realizing ultraviolet curing without heating, making the connection of the tail gas pipeline unit more convenient.

[0146] The sealing structure 1703 is made of any one of fluororubber and silicone rubber materials, and can play a good sealing role even at a relatively high temperature.

[0147] The first transition buffer structure 8 is a multi-layer composite structure including a ductile support layer, and the ductile support layer can match the heat insulation layer 1 and the inner side wall panel 3 with different coefficients of thermal expansion.

[0148] Compared with the prior art, a first transition buffer structure is provided between the heat insulation layer and the inner side wall panel of the present invention, and the flexible structure of its ductile support layer greatly improves the stress difference and cracking caused by different expansion rates of the heat insulation layer and the inner side wall panel during temperature change, and a good stress buffer layer is formed as a whole.

[0149] Among them, the difference in the coefficients of thermal expansion between the heat insulation layer 1 and the inner side wall panel 3 is between 8×10 -6 m / °C and 9×10 -6 m / °C. The first transition buffer structure 8 is a multi-layer composite structure, fixedly connected to the outer wall of the heat insulation layer 1, the inner side wall panel 3 is fixedly connected to the outer wall of the first transition buffer structure 8, and the radial filling structure 4 is fixed to the outer wall of the inner side wall panel 3. The setting of the first transition buffer structure solves the problem of easy cracking due to different coefficients of thermal expansion at high temperature differences in the prior art, and the shear strength of the inner side wall is increased from 55 MPa to 60 MPa compared with the prior art.

[0150] Specifically, a first transition buffer structure 8 is provided between the inner side wall panel 3 and the heat insulation layer 1. As Figure 1 and Figure 7 shown, the first transition buffer structure 8 includes a first rigid connection layer 801, a first ductile support layer 802, and a second rigid connection layer 803 sequentially distributed from the high-temperature area to the low-temperature area; the first rigid connection layer 801, the first ductile support layer 802, and the second rigid connection layer 803 are connected by an adhesive. Among them, the first rigid connection layer 801 is fixedly connected to the outer wall of the heat insulation layer 1, and the second rigid connection layer 803 is fixedly connected to the inner wall of the inner side wall panel 3.

[0151] The first rigid connection layer 801 and the second rigid connection layer 803 can be glass fiber felts; the glass fiber felts are selected as glass fiber felts with a fiber length of 2-10 mm; the glass fiber felts are selected as chopped strands. That is, the first transition buffer structure 8 adopts a transition buffer structure of glass fiber felt + glass fiber cloth + glass fiber felt.

[0152] The first ductile support layer can be a glass fiber cloth; the glass fiber cloth can be: twill cloth, twill cloth, plain cloth, preferably twill cloth with good shear and tensile resistance, preferably 170 g / cm 3 to 220 g / cm 3 twill cloth. Glass fiber cloth with too heavy gram weight has a larger thickness or too dense weaving density, which is not conducive to the adhesive entering to play an adhesive role and is not conducive to improving the adhesive strength; glass fiber cloth with too light gram weight has a smaller thickness or too small weaving density, and the strength of the glass fiber cloth itself is too small, which is also not conducive to improving the adhesive strength.

[0153] The adhesive contains: high-temperature resistant epoxy powder, high-temperature resistant toughening agent and high-temperature resistant diluent; the high-temperature resistant epoxy powder can be preferably EH301 epoxy resin; the mass ratio of the high-temperature resistant epoxy powder, high-temperature resistant toughening agent and high-temperature resistant diluent is: 1: 0.05 - 0.3: 0.05 - 0.2.

[0154] Preferably, the expansion coefficient of the heat insulation layer 1 is 0.13×10 -6 m / °C to 0.2×10 -6 m / °C, and the expansion coefficient of the material of the inner side wall plate 3 is not greater than 9×10 -6 m / °C. The range of the thermal expansion coefficients of the heat insulation layer 1 and the inner side wall plate 3 needs to be controlled within a suitable range. If the difference is too large, it will exceed the buffer range generated and not match the first toughness support layer.

[0155] Specifically, the first rigid connection layer 801 of the first transition buffer structure 8 includes 2 - 3 layers of fiberglass mats, the first toughness support layer 802 includes 1 - 3 layers of fiberglass cloth, and the second rigid connection layer 803 includes 2 - 3 layers of fiberglass mats. The first transition buffer structure 8 can be constructed by the way of laying layers in sequence. For example, 2 - 3 layers of fiberglass mats are laid on the heat insulation layer, then 1 - 3 layers of fiberglass cloth are laid, and then 2 - 3 layers of fiberglass mats are laid. By this way, the first transition buffer structure is constructed. The unique flexible structure of the fiberglass cloth greatly improves the stress difference and cracking caused by different expansion rates of the heat insulation layer and the inner side wall plate during temperature change, and a good stress buffer layer is formed as a whole; while the fiberglass mats adjacent to the heat insulation layer and the outer side wall plate are respectively tightly fixed and connected, effectively avoiding the defects of the weak strength of the fiberglass cloth body and insufficient shear resistance.

[0156] Specifically, the matrix resin of the heat insulation layer can be one or more of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, or one or more of the modified resins of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin.

[0157] Compared with the prior art, the above resins have better high-temperature stability and strength: phenolic resin, silicon-containing arylacetylene resin, and arylacetylene resin contain aromatic group structures and have better rigidity and high-temperature resistance; at the same time, silicone resin and silicon-containing arylacetylene resin contain heat-resistant silicon-oxygen bonds, which have better thermal stability than carbon-oxygen bonds.

[0158] Further preferably, the resin adopts hybrid phenolic resin PF-45, that is, interpenetrating phase composite material modified phenolic resin, which can be ceramized on its surface at high temperature and has better heat insulation performance. At the same time, it has a uniform nanoporous structure inside, further improving the heat insulation performance.

[0159] Preferably, the heat and insulation layer adopts a fiber-reinforced resin matrix structure, and the fiber is one or a mixture of quartz fiber, carbon fiber, high silica fiber, and basalt fiber. Among them, carbon fiber and quartz fiber have a hollow structure and are lightweight. Specifically, a fiber-reinforced resin matrix composite material can be obtained by filling reinforcing fibers in a resin matrix to prepare the heat and insulation layer.

[0160] Compared with the prior art, adding a reinforcing material to the resin matrix can greatly improve the strength, rigidity, and wear resistance of the heat and insulation layer, and it is not easy to cause damage and friction shedding of the heat and insulation layer body; at the same time, the reinforcing material helps to increase the glass transition temperature of the heat and insulation layer, thereby improving the high-temperature resistance performance.

[0161] Preferably, in the heat and insulation layer, a fiber-reinforced structure layer can be arranged between layers of the resin matrix material. Specifically, the fiber-reinforced structure layer adopts one or several of the methods of fiber braided structure layer, fiber cloth laminated paving layer, chopped strand mat layer, chopped strand mat needle punching layer, and fabric laminated needle punching layer.

[0162] Among them, fabric laminated needle punching is to set a needle punching structure through the fabric laminate, and further improve the bonding strength between layers in the heat and insulation layer through fabric laminated needle punching, thereby improving the anti-shedding ability of the heat and insulation layer.

[0163] The inner side wall panel 3 can adopt a fiber-reinforced structure layer arranged between layers of the resin matrix material; the fiber reinforcement can be one or more of quartz fiber, carbon fiber, high silica fiber, and basalt fiber, preferably carbon fiber. The resin is any one of phenolic resin, silicone resin, silicon-containing aryl acetylene resin, aryl acetylene resin, epoxy resin, or a modified resin of phenolic resin, silicone resin, silicon-containing aryl acetylene resin, aryl acetylene resin, and epoxy resin, preferably EH301 epoxy resin.

[0164] An axial support structure 2 is further arranged between the inner side wall panel 3 and the outer side wall panel 5 of the present invention; the axial support structure 2 is located inside the radial filling structure 4 and fixed to the outer wall of the inner side wall panel 3. A plurality of axial support structures 2 are provided and are radially spaced apart in the tail gas pipeline, which can effectively improve the axial bending resistance and shear strength.

[0165] The axial support structure 2 includes an internal filling structure 202 and an external reinforcement structure 203 surrounding the internal filling structure 202; the external reinforcement structure 203 includes a panel 2031 fixedly connected to the inner side wall panel 3 and a reinforcing rib 2032 surrounding and fixing the internal filling structure 202.

[0166] The panel 2031 and the reinforcing rib 2032 can adopt a fiber-reinforced structure layer arranged between resin matrix material layers; the fiber-reinforced structure can be selected from one or more of quartz fiber, carbon fiber, high-silica fiber, and basalt fiber, and preferably carbon fiber. The resin is any one of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, epoxy resin, or a modified resin of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin, and preferably EH301 epoxy resin.

[0167] The internal filling structure 202 can adopt a low-density material; further, a solid material or a hollow material with internal air holes or bubbles can be selected; the hollow material is preferably one or a combination of high-temperature-resistant PEI foam and PMI foam.

[0168] The internal filling structure 202 and the external reinforcing structure 203 can be made of different materials; the setting method of the axial support structure of the cylindrical part can be: arranging a plurality of independent axial support structures evenly along the circumferential direction of the cylindrical part or arranging a plurality of groups of axial support structures evenly along the circumferential direction of the cylindrical part, that is to say, a plurality of individual axial support structures can be set or a plurality of axial support structures formed by several axial support structures as a group can be set.

[0169] Specifically, when a plurality of independent axial support structures 2 are arranged evenly along the circumferential direction of the cylindrical part, there is a gap between adjacent axial support structures 2; when a plurality of groups of axial support structures are arranged evenly along the circumferential direction of the cylindrical part, there is a gap between adjacent groups of axial support structures, and there is a gap or no gap between several axial support structures within the group of axial support structures. Exemplarily, as Figure 1 shown, 3 axial support structures form a group of axial support structures, and 4 groups of axial support structures are arranged evenly along the circumferential direction of the cylindrical part.

[0170] It should be noted that several axial support structures in each group of axial support structures can be integrally formed or separately formed. When several axial support structures in each group of axial support structures are integrally formed, the common panel 2031 of several axial support structures is laid as a whole, the positions of several filling structures 202 are positioned on the common panel 2031, and then the reinforcing ribs 2032 of the external reinforcing structures 203 of several axial support structures are laid as a whole, so as to form an integrally formed group of axial support structures. At this time, there is no gap between several axial support structures in the group of axial support structures.

[0171] Compared with the prior art, the introduction of the fiber-reinforced structure enhances the strength of the resin, while reducing the resin fluidity, improving the forming processability of the axial support structure 2 and the inner side wall panel 3, and expanding the types of processable shapes. At the same time, the introduction of the fiber-reinforced structure makes it easier to connect multiple axial support structures 2 by sharing the fiber-reinforced structure among the multiple axial support structures 2, and an axial support structure 2 assembly with higher strength can be obtained. Further, between the outer wall of the radial filling structure 4 and the outer side wall panel 5, a plurality of radial support structures 6 are axially spaced along the exhaust gas pipeline, such as Figure 1 shown: The radial support structure 6 can be 2 to 5 pieces, which can effectively improve the radial bending and shear strength.

[0172] Further, the interiors of the radial filling structure 4, the axial support structure 2, and the radial support structure 6 are filled with materials having a lower density, with a lower overall weight. At the same time, the interiors of the axial support structure 2 and the radial support structure 6 can be filled with lightweight materials having a hollow microporous or bubble structure, which reduces the energy transfer rate while having a lower weight, and plays a heat insulation and sound insulation effect. On the one hand, the hollow structure contains gas and has a good heat insulation effect compared with solid materials. On the other hand, after sound waves are refracted or reflected at the gas-solid interface of the hollow structure and interfere with the incident sound waves, a sound absorption effect is achieved.

[0173] Compared with the prior art, the exhaust gas pipeline of the support structure of the present embodiment simultaneously has large radial, axial bending and shear strengths. In addition, since the interiors of the radial filling structure 4, the axial support structure 2, and the radial support structure 6 are filled with materials having a density lower than that of the outer reinforcing structure 203 and the heat insulation and protection layer 1, the inner and outer side wall panels 2, and the outer side wall panel 5 of the axial support structure 2, it has a lower overall weight.

[0174] The low-density material can be a solid material or a hollow material with hollow micropores or bubbles. The hollow material is preferably one or a combination of high-temperature resistant PEI (polyetherimide) foam and PMI (polymethacrylimide) foam, which overcomes the defects of the traditional support structure having a large mass and rapid energy transfer loss. Specifically, the radial filling structure 4, the radial support structure 6, and the internal filling structure 202 are made of commercially available high-temperature resistant PEI (polyetherimide) foam with a porosity of 50 to 70%.

[0175] As Figure 1 shown, at the location where the radial support structure 6 is provided, the outer side wall panel 5 is fixedly connected to the radial support structure 6 through the second transition buffer structure 10; at the location where the radial support structure 6 is not provided, the outer side wall panel 5 is fixedly connected to the radial filling structure 4 through the second transition buffer structure 10. The outer side wall panel 5 can further play a supporting and heat insulation role.

[0176] The outer wall panel 5 may optionally be made of an inorganic non-metallic material, metal, thermoplastic resin, and thermosetting resin with relatively high rigidity; for weight reduction considerations, thermoplastic resins and thermosetting resins are preferred; for improving rigidity at normal temperature and high temperature, thermosetting resin materials are preferred.

[0177] The outer wall panel 5 may adopt a fiber-reinforced structure layer arranged between resin matrix material layers; the fiber reinforcement structure may be one or more of quartz fiber, carbon fiber, high-silica fiber, and basalt fiber, and carbon fiber is preferred. The resin is any one of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, epoxy resin, or a modified resin of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin, and EH301 epoxy resin is preferred.

[0178] Compared with the prior art, a second transition buffer structure is provided between the radial support structure and the outer wall panel of the present invention. The flexible structure of its toughness support layer greatly improves the stress difference and cracking caused by different expansion rates of the radial support structure and the outer wall panel during temperature changes, and a good stress buffer layer is formed as a whole.

[0179] Among them, the difference in the coefficient of thermal expansion between the outer wall panel 5 and the radial support structure 6 or the radial filling structure 4 is between 35×10 - 6 m / ℃ and 41×10 -6 m / ℃. The second transition buffer structure 10 is a multi-layer composite structure, and the inner wall of the second transition buffer structure 10 is fixedly connected to the outer wall of the radial support structure 6 or the radial filling structure 4. The setting of the second transition buffer structure solves the problem of easy cracking due to different coefficients of thermal expansion at high temperature differences in the prior art, and the shear strength of the outer wall is increased from 60 MPa to 70 MPa compared with the prior art.

[0180] Specifically, a second transition buffer structure 10 is provided between the outer wall panel 5 and the radial support structure 6 or the radial filling structure 4, as Figure 1 and Figure 15 shown. The second transition buffer structure 10 includes a third rigid connection layer 1001, a second toughness support layer 1002, and a fourth rigid connection layer 1003 distributed in sequence from the high-temperature region to the low-temperature region; the third rigid connection layer 1001, the second toughness support layer 1002, and the fourth rigid connection layer 1003 are connected by an adhesive. Among them, the third rigid connection layer 1001 is fixedly connected to the outer wall of the radial support structure 6 or the radial filling structure 4, and the fourth rigid connection layer 1003 is fixedly connected to the inner wall of the outer wall panel 5.

[0181] The third rigid connection layer 1001 and the fourth rigid connection layer 1003 may be fiberglass mats; the fiberglass mats are selected as those with a fiber length of 10 mm to 15 mm for better flow guiding effect; the fiberglass mats are selected as chopped strands. That is, the second transition buffer structure 10 adopts a transition buffer structure of fiberglass mat + fiberglass cloth + fiberglass mat.

[0182] The second ductile support layer may be fiberglass cloth; the fiberglass cloth may be: twill cloth, satin cloth, plain cloth, preferably satin cloth with good shear and tensile resistance, preferably 170 g / cm 3 ~220 g / cm 3 satin cloth. If the gram weight of the fiberglass cloth is too heavy, the thickness is too large or the weaving density is too dense, which is not conducive to the adhesive entering and playing the bonding role, and is not conducive to improving the bonding strength; if the gram weight of the fiberglass cloth is too light, the thickness is too small or the weaving density is too small, and the strength of the fiberglass cloth itself is too small, which is also not conducive to improving the bonding strength.

[0183] The adhesive includes: high-temperature resistant epoxy powder, high-temperature resistant toughening agent and high-temperature resistant diluent; the high-temperature resistant epoxy powder may be EH301 epoxy resin; the mass ratio of the high-temperature resistant epoxy powder, high-temperature resistant toughening agent and high-temperature resistant diluent is: 1: 0.05 to 0.3: 0.05 to 0.2.

[0184] Preferably, since the outer side wall plate 5 and the radial support structure 6 or the radial filling structure 4 are located outside the tail gas pipeline, the temperature difference between layers is much smaller than that of the heat insulation layer 1 and the inner side wall plate 3; the difference in the thermal expansion coefficients of the actual radial support structure 6 or the radial filling structure 4 and the outer side wall plate 5 allows a large range. The expansion coefficient of the outer side wall plate 5 is 9×10 -6 m / ℃~15×10 -6 m / ℃, and the material expansion coefficient of the radial support structure 6 or the radial filling structure 4 is not greater than 50×10 -6 m / ℃. The range of the thermal expansion coefficients of the heat insulation layer 1 and the inner side wall plate 3 needs to be controlled within a suitable range. If the difference is too large, it will exceed the buffer range mismatch with the second ductile support layer.

[0185] Specifically, the third rigid connection layer 1001 of the second transition buffer structure 10 includes 2 to 3 layers of fiberglass mats, the second ductile support layer 1002 includes 1 to 3 layers of fiberglass cloth, and the fourth rigid connection layer 1003 includes 2 to 3 layers of fiberglass mats. The second transition buffer structure 10 can be constructed by laying layers in sequence. For example, 2 to 3 layers of fiberglass mats are laid on the radial support structure or the radial filling structure, then 1 to 3 layers of fiberglass cloth are laid, and then 2 to 3 layers of fiberglass mats are laid. By this method, the second transition buffer structure is constructed. The unique flexible structure of the fiberglass cloth greatly improves the stress difference and cracking caused by the different expansion rates of the outer side wall panel and the radial support structure or the radial filling structure during temperature changes, and overall forms a good stress buffer layer. The fiberglass mats adjacent to the outer side wall panel, the radial support structure, and the radial filling structure are respectively tightly fixed and connected, effectively avoiding the defects of the weak strength of the fiberglass cloth body and insufficient shear resistance.

[0186] In order to further improve the corrosion resistance, water resistance, and antistatic performance of the tail gas pipeline, an external coating 7 can be provided outside the outer side wall panel 5, and the external coating 7 can be selected from three-proof paint materials.

[0187] On the other hand, the present invention also provides a forming method for the composite material tail gas pipeline system for preparing the above-mentioned composite material tail gas pipeline system, including the following steps:

[0188] Step 1: Impregnation molding of the heat-insulating layer 1. The heat-insulating layer is prepared in a mold by using a vacuum impregnation process.

[0189] Specifically, the core mold and the preform of the heat-insulating layer are placed in a cylindrical cavity mold, the resin is introduced into the circular cavity mold, and the main body of the cylindrical cavity mold and the cover plate are locked by using bolts. The resin is fully infiltrated into the preform by using a vacuum impregnation method, and the vacuum degree of the vacuum impregnation shall not be lower than 980 mbar. The mold temperature is raised to 80°C to 180°C by using a self-heating device to cure the resin for 12 h to 24 h, and the heat-insulating layer is obtained through demolding and processing.

[0190] The core mold is a cylindrical mold nested in the cylindrical cavity mold, and a cylindrical heat-insulating layer is formed in the area between the core mold and the cylindrical cavity mold.

[0191] Step 2: Laying the first transition buffer structure 8;

[0192] Specifically, taking the outer surface of the heat-insulating layer as the reference surface, epoxy glue is brushed on its surface, 2 to 3 layers of fiberglass mats are laid, then 1 to 3 layers of fiberglass cloth are laid, and then 2 to 3 layers of fiberglass mats are laid. An adhesive is sprayed between the laid layers to complete the laying of the first transition buffer structure.

[0193] Compared with the prior art, in step 2, a structure is adopted in which 2 to 3 layers of fiberglass felts are laid on the heat insulation layer, then 1 to 3 layers of fiberglass cloths are laid, and then 2 to 3 layers of fiberglass felts are laid. The unique flexible structure of the fiberglass cloth greatly improves the stress difference and cracking caused by different expansion rates of the two connected layers during temperature change, and a good stress buffer layer is formed as a whole; while the fiberglass felts adjacent to the heat insulation layer and the inner side wall plate are respectively tightly fixedly connected, effectively avoiding the defect that the fiberglass cloth body has insufficient strength and poor shear resistance. The fiberglass felt adopts one of the forms of chopped strand mat, chopped strand needle punched felt, and fabric laminated needle punched felt; the thicknesses of the fiberglass felt and the fiberglass cloth adopt the thicknesses of commonly used products on the market, and the present invention does not make special limitations.

[0194] Step 3: Vacuum infusion molding of the inner side wall plate 3

[0195] On the outer wall of the first transition buffer structure, the fiber skeleton of the inner side wall plate preform, the release cloth, the isolation film, and the flow guiding net are sequentially laid from the side close to the heat insulation layer. Injection channels and outlet channels are set, injection ports and outlet ports are installed, a vacuum bag is laid and evacuated to lock the vacuum bag, and the negative pressure operation gradually increases between 600 and 980 mbar after starting; further proceed according to the following steps:

[0196] Step 3.1 Transport the inner side wall plate preform placed in the vacuum bag to the heating equipment after evacuation, and set the temperature of the heating equipment to 170°C to 130°C;

[0197] Step 3.2 Raise the temperature of the resin to 100°C to 170°C, and introduce the resin into the inner side wall plate preform;

[0198] Step 3.3 After the injection is completed, raise the temperature of the oven to 130°C to 150°C and keep it warm for 3 hours, then raise the temperature of the oven to 170°C to 180°C and keep it warm for 2 hours. The product cools down with the furnace, and after demolding, it is surface polished and cleaned to obtain the inner side wall plate. The fiber skeleton of the inner side wall plate preform is selected from one or more of quartz fiber, carbon fiber, high silica fiber, and basalt fiber.

[0199] In steps 2 and 3, the resin selected can be a high-temperature resistant thermosetting resin, preferably a high-temperature resistant epoxy resin, phenolic resin, or silicone resin; further preferably EH301 epoxy resin.

[0200] Compared with the prior art, in step 3, the resin temperature is preheated to 100°C to 170°C, which is lower than the heating temperature of 170°C to 130°C set for the outer wall panel preform in the oven. After the injection of glue is completed, the oven temperature is raised to 130°C to 150°C and kept warm for 3 hours, and then the oven temperature is raised to 170°C to 180°C and kept warm for 2 hours. Since the heat dissipation of the resin and the environment is a process from the outside to the inside of the resin, preheating the resin temperature lower than the temperature set for the outer wall panel preform in the oven can accelerate the flow rate of the resin outer wall relative to the inside, which helps the resin to disperse and distribute into fine structures, reduce the lack of glue and incompleteness. At the same time, the lower temperature can further reduce the resin reaction rate, which is beneficial to the uniform dispersion of the resin.

[0201] Compared with the prior art, the temperature setting is divided into three main stages: the first stage where the initial temperature set for the outer wall panel preform in the oven is 170°C to 130°C, and the subsequent two stages where the oven temperature is further set to 130°C to 150°C and 170°C to 180°C. The corresponding staged setting of the temperature is more in line with the laws of resin flow, dispersion, and curing: in the first stage, after the injection of glue, the glue mainly flows in the main trunk roads and large spaces, with little resistance, and there is no need to deliberately set a higher temperature to reduce the viscosity and improve the fluidity. The lower temperature helps to delay curing; in the second stage, the main resin disperses into fine structures. At this time, since the resin has been heated during the flow process and partial solidification occurs, resulting in an increase in viscosity and a decrease in fluidity, it is necessary to appropriately increase the temperature to improve the fluidity at this time; in the third stage, since the glue has been dispersed sufficiently in the second stage and a relatively high degree of curing has occurred at the same time, it is necessary to further increase the temperature to enhance the curing crosslinking degree of the resin, thereby enhancing the strength of the resin.

[0202] Step 4: The axial support structure 2 is formed, and the axial support structure is prepared in a mold by using the autoclave process.

[0203] Specifically, it includes the following steps:

[0204] Step 4.1: Pour the external reinforcement structure 203 into the mold: As Figure 5 shown, lay the carbon fiber fabric prepreg on the mold sprayed with the release agent as the panel 2031 of the external reinforcement structure 203; the carbon fiber fabric prepreg is impregnated with a thermosetting resin to ensure that the carbon fiber fabric is fully coated with the thermosetting resin. The thermosetting resin can be a single-component epoxy resin. In order to ensure the tightness of the bonding of the fiber prepreg and ensure the uniform thickness of each layer of the fiber prepreg, the fiber prepreg is vacuum-compacted once every 3 to 5 layers; the time is 15 minutes to 50 minutes, and the negative pressure operation gradually increases within the range of 600 mbar to 980 mbar after it starts.

[0205] Compared with the prior art, laying carbon fiber fabric prepreg is more conducive to the complete penetration of the adhesive into the carbon fiber and achieving a more uniform effect than the carbon fiber injection molding process; vacuum compaction once every 3 to 5 layers of fiber prepreg helps to exhaust air and make the force application uniform, thus controlling the morphology after molding.

[0206] Step 4.2: Use the laser projection method to locate the position of the internal filling structure 202 on the panel 2031. As Figure 5 shown, lay prepreg layer by layer on the foam processed into a suitable shape and fixed shape as the reinforcing rib 2032 of the external reinforcing structure 203; after laying one layer of prepreg, use a positioning tooling for positioning and perform pre-compaction treatment by means of thermal compaction, with the compaction temperature being 130°C to 140°C and the compaction time being 15 min to 30 min; after laying each layer of prepreg in the same way, lay a release cloth, a uniform pressure plate, a perforated separator film, and a breather felt in sequence outside the outermost layer of prepreg and then place them inside a vacuum bag provided with an air extraction hole.

[0207] Compared with the prior art, using a positioning tooling for positioning and hot pressing after laying each layer of prepreg can ensure the integrity of molding to the greatest extent. The positioning tooling is used to replace the vacuum bag molding process in the prior art, and vacuum pumping is only carried out after all prepregs are laid, greatly simplifying the vacuum molding process compared with the prior art; at the same time, the positioning tooling matching the shape of the internal filling structure 202 can greatly avoid the phenomenon of residual glue at the contact rounded corners between the foam and the panel 2031, ensuring the stability of the designed shape.

[0208] Step 4.3: Transfer the vacuum bag and the axial support structure inside the vacuum bag to an autoclave, evacuate the vacuum bag to a negative pressure, and gradually increase it within the range of 600 mbar to 980 mbar after the negative pressure operation starts; raise the temperature of the autoclave to 130°C to 150°C and keep it warm for 3 h - 4 h, then raise the temperature of the autoclave to 170°C to 180°C and keep it warm for 2 h - 4 h, with the molding pressure being 0.4 MPa to 0.6 MPa; during this period, the vacuum bag maintains a stable vacuum state; the rough product of the axial support structure cools down with the furnace, and after demolding, it is trimmed to obtain the axial support structure.

[0209] Compared with the prior art, the negative pressure operation of this method adopts the method of gradually increasing the pressure in the range of 600mbar to 980mbar after the start, which is conducive to gradually increasing the vacuum pressure and exhaust capacity as the thermosetting resin solidifies and the viscosity increases, ensuring that the resin-containing material is subjected to continuous and stable pressure from the outside of the vacuum bag during the resin curing process, avoiding the phenomenon of compression weakness and large molding thickness under negative pressure conditions as the resin viscosity increases; at the same time, it also avoids the resin overflow and waste caused by excessive vacuum pressure and fast compression speed when the resin viscosity is low in the initial stage. Compared with the prior art, the rough finished product of the axial support structure is cooled with the furnace, which can minimize the temperature difference between the inside and outside of the axial support device and avoid stress caused by different thermal expansion coefficients between the foam and the external reinforcement structure.

[0210] Furthermore, the carbon fiber fabric prepregs of the present invention can obtain a quasi-isotropic structure by adjusting the laying angle. The carbon fiber fabric prepreg must contain at least 4 layers, and each layer must have the same stiffness and thickness. The bottom layer of carbon fiber fabric prepreg is initially set as the 0° layer, and its fiber placement direction is the initial zero degree. The fiber laying directions of the remaining layers of carbon fiber fabric prepreg are different from the fibers of the bottom layer of carbon fiber fabric prepreg in the laying plane and have a certain inclination angle. The fibers in different directions also have specific strengths, such as Figure 6 As shown:

[0211] Bottom carbon fiber fabric prepreg layer (0° layer) 902: provides axial strength and stiffness, ideal for components that must withstand axial loads.

[0212] A layer (45° layer) 903 rotated 45° counterclockwise relative to the underlying carbon fiber fabric prepreg layer: provides shear and torsional strength and stiffness.

[0213] 45° layer (-45° layer) rotated clockwise relative to the bottom carbon fiber fabric prepreg layer 904: provides shear and torsional strength and stiffness.

[0214] The 90° layer (90° layer) 901 is rotated relative to the underlying carbon fiber fabric prepreg layer: it provides lateral strength and stiffness, holds the layers together and provides resistance to compression.

[0215] Compared with the prior art, the carbon fiber fabric prepregs described in the present invention can obtain a quasi-isotropic structure by adjusting the laying angle, and simultaneously have axial strength and stiffness, shear and torsional strength and stiffness, and shear and torsional strength and stiffness; the quasi-isotropic structure can produce a hard material with strength in all directions.

[0216] Step 5: Assemble the inner wall panel and the axial support structure;

[0217] Specifically, fixedly connect the axial support structure at the preset position of the inner side wall panel imported in step 3 to obtain a prefabricated tail gas pipeline body covered with the axial support structure; roughen the outer surface of the inner side wall panel by means of electric grinding, and clean the outer surface of the inner side wall panel with cleaning agent acetone or ethanol.

[0218] Among them, lay the adhesive film at the preset position by means of laser projection, place the axial support structure on the adhesive film, position the axial support structure, lay the release cloth and the breather felt, arrange the air extraction port and make a bag, transfer the axial support structure and the assembly to the oven, gradually increase the pressure between 600 mbar and 980 mbar after the negative pressure operation starts, raise the oven temperature to 130 °C to 150 °C and keep it warm for 3 h, then raise the oven temperature to 170 °C to 180 °C and keep it warm for 2 h to cure the adhesive film, and after demoulding, assemble the remaining axial support structures in the same way. After assembly, process the glue accumulation area to obtain a tail gas pipeline provided with an axial support structure. The adhesive film selected in this step can be a high-temperature resistant thermosetting resin adhesive film, preferably a high-temperature resistant epoxy resin or silicone resin; further preferably, it is the EH601 high-temperature resistant structural adhesive film; the thickness of the adhesive film is 0.1 mm to 0.2 mm, and the number of layers of the laid adhesive film is 1 to 2 layers.

[0219] Step 6: Fixation of the radial filling structure and the radial support structure

[0220] Bond and fix the radial filling structure on the outer wall of the prefabricated tail gas pipeline body covered with the axial support structure; further bond and fix the radial support structure on the outer wall of the radial filling structure, and cure and form under vacuum to obtain a prefabricated tail gas pipeline body with a radial filling structure and a radial support structure.

[0221] Specifically, it includes the following steps:

[0222] Step 6.1: Fix the cut and formed radial filling structure on the inner side wall panel coated with the adhesive, further use the positioning tooling to position the radial support structure of the radial support structure on the outer wall of the radial filling structure, lay the glass fiber prepreg between the radial support structure and the radial filling structure, lay the release cloth, the isolation film and the breather felt on the remaining sides of the radial support structure in sequence, place the laid radial support structure and the initial tail gas pipeline in the vacuum bag and arrange the air extraction port; the glass fiber selected in the glass fiber prepreg is not specifically limited in the present invention; the resin selected in the glass fiber prepreg can be a high-temperature resistant thermosetting resin, preferably one or more of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin and epoxy resin or modified resins of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin and epoxy resin; further preferably, it is the EH301 epoxy resin.

[0223] Schematic diagram of the vacuum impregnation process or the vacuum infusion process is as Figure 4As shown in the figure: Place the preform 12 to be formed inside the vacuum bag 13; Seal the vacuum bag 13, the preform 12 to be formed and the mold 15 in the autoclave 14, and connect it to the outside of the autoclave 14 through the vacuum extraction port 16. The autoclave 14 is provided with an autoclave air inlet and outlet 1401, and adjustable pressure hot compressed gas can be introduced through the autoclave air inlet and outlet 1401 to adjust the air pressure and temperature inside the autoclave 14; When the vacuum bag 13 is evacuated, the intake air of the autoclave 14 can exert pressure on the vacuum bag 13 and the preform 12 to be formed, and the hot pressing and shaping of the preform 12 to be formed is completed.

[0224] Compared with the prior art, adding the isolation film and the breathable felt in this step can absorb a larger amount of resin, and play a role in guiding the excess resin, preventing the accumulation of excess resin from affecting the appearance of the finished product.

[0225] Step 6.2: Keep the vacuum bag and the initial tail gas pipeline at 130°C - 150°C for 2h - 6h, and then further heat up to 170°C - 180°C and keep it for 1h - 4h to cure the prepreg; Compared with the prior art, this step adopts a two-stage heating process to control the resin flow and curing rate, and cures after the resin fully flows and disperses; If the resin cures too quickly, it will lead to insufficient polymerization flow and uneven dispersion, resulting in partial lack of glue; And if the heating time in the first stage is too long, the residual effective glue content of the glass fiber prepreg will be less, which is not conducive to improving the connection strength between the radial support structure and the initial tail gas pipeline.

[0226] Step 7: Lay the second transition buffer structure

[0227] Lay 2 - 3 layers of glass fiber felt on the radially supported structure fixed in Step 6, then lay 1 - 3 layers of glass fiber cloth, and then lay 2 - 3 layers of glass fiber felt to complete the laying of the second transition buffer structure.

[0228] Step 8: Vacuum infusion molding of the outer side wall panel

[0229] On the outside of the second transition buffer structure that has been laid, prepare the outer side wall panel by vacuum infusion process on the outer wall of the preform of the tail gas pipeline with a radially supported structure.

[0230] The inventor found that: The on-site foaming processes of PEI (polyetherimide) foam, PMI (polymethacrylimide) foam and ordinary foam are different. In the prior art, the processes of pre-forming, cutting and machining, and then assembling are all adopted, and there are the following defects in the thermosetting forming process of the outer side wall panel 5, such as Figure 3 As shown in the figure:

[0231] (1) Glue accumulation at the corners of the radially supported structure;

[0232] (2) Appearance deformation at the corners of the radially supported structure.

[0233] Figure 2 Indicates the normal state without caking Figure 3 Indicates the presence of caking and abnormal shapes, where 5 represents the outer wall panel and 11 is the caking and abnormal shape area outside the outer wall panel.

[0234] The above defects seriously affect the product usage and are also the main influencing factors for the fact that PEI (polyetherimide) foam and PMI (polymethacrylimide) foam in the prior art cannot be directly used for weight reduction of the support structure.

[0235] To improve the above defects, the present invention also provides a forming method for the outer wall panel of the tail gas pipeline provided with a radial support structure, specifically including the following steps:

[0236] Outside the second transition buffer structure that has been laid, lay the fiber skeleton of the outer wall panel preform, release cloth, isolation film, and 2 layers of flow guiding nets; when laying the release cloth and the flow guiding nets, the rounded corners need to be cut open, lapped, and shaped rubber should be placed at the rounded corners to ensure the quality of the rounded corners of the outer wall panel; set the injection pipeline and the outlet pipeline, install the injection port and the outlet port, lay the vacuum bag film and evacuate to lock the vacuum bag film, transport the outer wall panel preform to the heating equipment, set the oven temperature to 170°C to 130°C, raise the resin temperature to 100°C to 170°C, introduce the resin into the outer wall panel preform, after the injection is completed, raise the oven temperature to 130°C to 150°C and keep it warm for 3h, then raise the oven temperature to 170°C to 180°C and keep it warm for 2h, let the product cool down with the furnace, and perform surface grinding and cleaning after demolding to obtain the outer wall panel. The fibers of the outer wall panel preform are selected from one or more of quartz fiber, carbon fiber, high silica fiber, and basalt fiber.

[0237] In the heat insulation layer, a fiber reinforced structure layer can be arranged between resin matrix material layers. Specifically, the fiber reinforced structure layer adopts one or several of the ways of fiber braided structure layer, fiber cloth laminated paving layer, chopped strand mat layer, chopped strand mat needle punching layer, and fabric laminated needle punching layer. The resin selected in this step can be one or more of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin, or one or more of the modified resins of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin, preferably high-temperature resistant epoxy resin, phenolic resin, and silicone resin; further preferably EH301 epoxy resin.

[0238] Compared with the prior art, in this embodiment, 2 to 3 layers of glass fiber mats are laid on the radial support structure or the radial filling structure, then 1 to 3 layers of glass fiber cloth are laid, and then 2 to 3 layers of glass fiber mats are laid. The second transition buffer structure is constructed in this way. The unique flexible structure of the glass fiber cloth greatly improves the stress difference and cracking caused by the different expansion rates of the outer side wall panel and the radial support structure or the radial filling structure during temperature change, and a good stress buffer layer is formed as a whole. The glass fiber mats adjacent to the outer side wall panel, the radial support structure and the radial filling structure are respectively tightly fixedly connected, effectively avoiding the defects of the glass fiber cloth with insufficient body strength and shear resistance.

[0239] Compared with the prior art, in step 8, the resin temperature is preheated to 100°C to 170°C, which is lower than the heating temperature of 170°C to 130°C set for the outer side wall panel preform in the oven. After the injection of glue is completed, the oven temperature is raised to 130°C to 150°C and kept warm for 3 hours, and then the oven temperature is raised to 170°C to 180°C and kept warm for 2 hours. Since the heat dissipation of the resin and the environment is a process from the outside to the inside of the resin, the resin temperature is preheated to be lower than the temperature set for the outer side wall panel preform in the oven. Such a temperature setting can accelerate the flow rate of the resin outer wall relative to the inside, contribute to the dispersion and distribution of the resin to the fine structures, reduce the lack of glue and incompleteness, and at the same time, the lower temperature can further reduce the resin reaction rate, which is beneficial to the uniform dispersion of the resin.

[0240] Compared with the prior art, the temperature setting is divided into three main stages: the first stage in which the initial temperature of the outer side wall panel preform in the oven is set to 170°C to 130°C, and the oven temperature is further set to 130°C to 150°C and 170°C to 180°C in the subsequent two stages. The corresponding staged temperature setting better matches the resin flow, dispersion and curing laws: in the first stage, after the injection of glue, the glue mainly flows in the main trunk roads and large spaces, with small resistance. There is no need to deliberately set a relatively high temperature to reduce the viscosity and improve the fluidity. The lower temperature helps to delay the curing; in the second stage, the main resin disperses to the fine structures. At this time, since the resin has been heated during the flow process and partial solidification occurs, resulting in an increase in viscosity and a decrease in fluidity, it is necessary to appropriately increase the temperature to improve the fluidity at this time; in the third stage, since the glue has been relatively fully dispersed in the second stage and a relatively high degree of curing has occurred at the same time, it is necessary to further increase the temperature to enhance the curing crosslinking degree of the resin, thereby enhancing the strength of the resin.

[0241] Compared with the prior art, when laying the release cloth and the flow guide net, the rounded corners need to be cut and overlapped, which can greatly increase the glue outflow rate of the excess glue and help reduce the glue accumulation. On the other hand, a conforming rubber is placed at the rounded corners, which can greatly improve the problem that the pressure given by the vacuum bag at the rounded corners is small and cannot be effectively tightened during vacuum pumping. The vacuum bag applies pressure through the conforming rubber to promote glue discharge and reduce glue accumulation. At the same time, due to the non-elastic recovery characteristic of the conforming rubber after being pressurized, the stable quality of the rounded corner shape design of the outer side wall panel is guaranteed.

[0242] Step 9: Three-proof coating:

[0243] Brush a three-proof paint on the surface of the cylindrical prefabricated part after the preparation of the outer side wall panel as an external coating.

[0244] Step 10: Fixed connection of the tail gas pipeline unit

[0245] Step 10.1: Install and position at both ends of the two tail gas pipeline units inside the housing; pass the two tail gas pipeline units through the sealing structure 1703 and abut and align them.

[0246] Step 10.2: Inject resin into the housing for curing and molding. Inject resin from the resin injection hole and cure under thermal curing or light curing conditions.

[0247] The thermosetting resin is one or more of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, epoxy resin, or modified resins of phenolic resin, silicone resin, silicon-containing arylacetylene resin, arylacetylene resin, and epoxy resin.

[0248] The photocuring resin is a photosensitive acrylate resin and its modified products.

[0249] Preferably, the housing is made of a transparent material; the resin is a photosensitive acrylate resin.

[0250] The sealing structure is made of any one of fluororubber and silicone rubber materials.

[0251] Compared with the prior art, the present invention adopts an injection molding process of injecting glue at the connection of the tail gas pipeline units, which can achieve good strength and sealing performance.

[0252] Using a transparent material housing and using a photosensitive acrylate resin to prepare the fixed connection layer, realizing ultraviolet curing without heating, making the connection of the tail gas pipeline units more convenient.

[0253] The sealing structure is made of any one of fluororubber and silicone rubber materials, and can play a good sealing role even at a relatively high temperature.

[0254] To illustrate the technological progress of the present invention, the GB / T 3139-2005 "Test Method for Thermal Conductivity of Fiber Reinforced Plastics" was further used to test the thermal conductivity of the thermosetting resin material involved in the present invention.

[0255] To illustrate the technological progress of the present invention, the GB / T 1450.1-2005 "Test Method for Interlaminar Shear Strength of Fiber Reinforced Plastics" was further used to test the shear strength of the thermosetting resin material involved in the present invention.

[0256] To illustrate the technological progress of the present invention, the following examples and comparative examples are further disclosed:

[0257] Example 1

[0258] This example discloses a forming method for a composite tail gas pipeline system for processing the above-mentioned composite tail gas pipeline system, including:

[0259] Step 1: Impregnation molding of the thermal insulation layer

[0260] Place the core mold and the preform into a cylindrical cavity mold, pour the resin into the circular cavity mold, lock the main body of the cylindrical cavity mold and the cover plate by means of bolt tightening, and use the vacuum impregnation method to fully infiltrate the preform with the resin. The vacuum degree of the vacuum impregnation is not less than 980 mbar. Use a self-heating device to raise the mold temperature to 90 °C to cure the resin for 24 h, and obtain the thermal insulation layer through demolding and processing. The core mold is a cylindrical mold nested in the cylindrical cavity mold, and a cylindrical thermal insulation layer is formed in the area between the core mold and the cylindrical cavity mold.

[0261] Step 2: Laying the first transition buffer structure

[0262] Taking the outer surface of the thermal insulation layer as the reference surface, brush epoxy glue on its surface, lay 3 layers of glass fiber mats, then lay 3 layers of glass fiber cloth, and then lay 3 layers of glass fiber mats. Spray adhesive between the laid layers to complete the laying of the first transition buffer structure.

[0263] Step 3: Vacuum infusion molding of the inner side wall panel

[0264] Outside the first transition buffer structure after laying is completed, lay the fiber skeleton of the inner wall panel preform of the carbon fiber fabric. Compact it under vacuum once every 3 to 5 layers. Sequentially lay the release cloth, isolation film, and flow guiding net. Set the injection pipeline and the outlet pipeline, install the injection port and the outlet port, lay the vacuum bag film and evacuate to lock the vacuum bag film; Transport the inner wall panel preform to the heating equipment, set the oven temperature to 130 °C, raise the resin temperature to 170 °C, introduce the resin into the inner wall panel preform. After the injection is completed, raise the oven temperature to 150 °C and keep it warm for 3 h, then raise the oven temperature to 180 °C and keep it warm for 2 h. The product cools down with the furnace. After demolding, perform surface grinding and cleaning to obtain the inner wall panel. The binder contains: EH301 epoxy resin powder, high-temperature resistant toughening agent, high-temperature resistant diluent; The dosage mass ratio is: 1:0.31:0.1; It can be used for a long time at 100 °C without aging. The resin used in this step is EH301 epoxy resin. The fiber skeleton of the inner wall panel preform is made of carbon fiber.

[0265] Step 4: Axial support structure forming

[0266] Step 4.1: Pour the external reinforcement structure 203 in the mold: Lay the carbon fiber fabric prepreg on the mold sprayed with the release agent as the panel 2031 of the external reinforcement structure 203; The carbon fiber fabric prepreg is impregnated with a thermosetting resin to ensure that the carbon fiber fabric is fully coated with the thermosetting resin. The thermosetting resin is EH301 epoxy resin. In order to ensure the tightness of the bonding of the fiber prepreg and ensure the uniform thickness of each layer of the fiber prepreg, compact the fiber prepreg under vacuum once every 3 layers; The time is 50 min, and it gradually increases between 600 mbar and 980 mbar after the negative pressure operation starts, and the increasing rate is 10 mbar / min.

[0267] Step 4.2: Use the laser projection method to locate the position of the internal filling structure 202 on the panel 2031, as Figure 5 shown, layer by layer lay the prepreg on the foam processed into a suitable shape and fixed shape as the stiffener 2032 of the external reinforcement structure 203; After laying one layer of prepreg, use the positioning tooling for positioning and perform pre-compaction treatment by thermal compaction, the compaction temperature is 140 °C, and the time is 15 min; After laying each layer of prepreg in the same way, sequentially lay the release cloth, equalizing plate, perforated isolation film, and breathable felt outside the outermost layer of prepreg and place it inside the vacuum bag provided with air extraction holes.

[0268] Step 4.3: Transfer the vacuum bag and the axial support structure inside the vacuum bag to the autoclave, evacuate the vacuum bag to a negative pressure, which gradually increases within the range of 600 mbar to 980 mbar after the negative pressure operation starts, and the increasing rate is 5 mbar / min; raise the temperature of the autoclave to 130 °C and keep it warm for 3 h, then raise the temperature of the autoclave to 170 °C and keep it warm for 2 h, and the forming pressure is 0.4 MPa; during this period, the vacuum bag maintains a stable vacuum state; the rough product of the axial support structure cools down with the furnace, and after demoulding, it is trimmed to obtain the axial support structure.

[0269] Step 5: Assemble the inner side wall panel and the axial support structure

[0270] Fix and connect the axial support structure at the preset position of the inner side wall panel imported in Step 3, roughen the outer surface of the inner side wall panel by means of electric grinding, clean the outer surface of the inner side wall panel with the cleaning agent acetone, lay the adhesive film at the preset position by means of laser projection, place the axial support structure on the adhesive film, position the axial support structure with an adhesive bonding tooling, sequentially lay the release cloth and the breather felt, arrange the air extraction port and make a bag, transfer the assembly to the oven, raise the temperature of the oven to 150 °C and keep it warm for 3 h, then raise the temperature of the oven to 180 °C and keep it warm for 2 h to cure the adhesive film, and after demoulding, assemble the remaining axial support structures in the same way. After assembly, process the glue accumulation area to obtain the tail gas pipeline provided with the axial support structure. In this step, the selected adhesive film is the EH601 high-temperature resistant structural adhesive film; the thickness of the adhesive film is 0.1 mm, and the number of layers of the laid adhesive film is 2 layers.

[0271] Step 6: Fix the radial filling structure and the radial support structure

[0272] Brush epoxy glue on the outer wall of the tail gas pipeline of the axial support structure prepared in Step 4 in the forming method of the axial support structure of the tail gas pipeline, and bond the cut and processed foam as the radial filling structure 4; further position the radial support structure on the outer wall of the radial filling structure 4, lay the glass fiber prepreg between the radial support structure and the initial tail gas pipeline, sequentially lay the release cloth, the isolation film and the breather felt on the other sides of the radial support structure, place the laid radial support structure and the initial tail gas pipeline in the vacuum bag and arrange the air extraction port; the resin in the glass fiber prepreg is the EH301 epoxy resin; keep the vacuum bag and the initial tail gas pipeline at 150 °C for 3 h, and then further raise the temperature to 180 °C and keep it warm for 2 h to cure the prepreg.

[0273] Step 7: Lay the second transition buffer structure

[0274] Lay 3 layers of glass fiber mats on the radial support structure installed in Step 6, then lay 1 layer of glass fiber cloth, and then lay 3 layers of glass fiber mats to complete the laying of the second transition buffer structure.

[0275] Step 8: Vacuum infusion molding of the outer wall panel

[0276] Outside the second transition buffer structure after laying is completed, lay the fiber skeleton of the prefabricated outer wall panel. Compact it by vacuum once every 3 - 5 layers laid. Sequentially lay the release cloth, isolation film, and 2 layers of flow guiding nets. When laying the release cloth and the flow guiding nets, cut at the rounded corners, make lap joints, and place conforming rubber at the rounded corners to ensure the quality of the rounded corners of the outer wall panel. Set up the injection pipe and the outlet pipe, install the injection port and the outlet port, lay the vacuum bag film and evacuate to lock the vacuum bag film. Transport the prefabricated outer wall panel to the heating equipment. Set the oven temperature to 130°C, raise the resin temperature to 110°C, and introduce the resin into the prefabricated outer wall panel. After the injection is completed, raise the oven temperature to 140°C and keep it warm for 3 hours, then raise the oven temperature to 170°C and keep it warm for 2 hours. Let the product cool down with the furnace. After demolding, perform surface grinding and cleaning to obtain the outer wall panel. The glass fiber mat is in the form of a chopped strand mat; the resin used in this step is EH301 epoxy resin. The fibers of the prefabricated outer wall panel are quartz fibers.

[0277] Step 9: Brush a three-proof paint on the surface of the tubular prefabricated part of the outer wall panel prepared as an external coating.

[0278] Step 10: Fixed connection of the tail gas pipeline unit

[0279] Step 10.1: Install and position at both ends of the two tail gas pipeline units inside the housing; Pass the two tail gas pipeline units through the sealing structure 1703 and abut and align them.

[0280] Step 10.2: Inject resin into the housing for curing and molding. Inject resin from the injection hole and cure under thermal curing or light curing conditions.

[0281] Example 2

[0282] This example discloses a composite tail gas pipeline system, which is prepared by the forming method of the above composite tail gas pipeline system. As Figure 16 shown, the tail gas pipeline system includes a tail gas pipeline unit 18 and a connection unit 17 arranged at the axial end of the tail gas pipeline unit for fixed connection of the tail gas pipeline unit;

[0283] The fixed connection layer 1702 is a photosensitive acrylate resin.

[0284] The housing 1701 is made of transparent PC material;

[0285] As Figure 1As shown, from the inside to the outside, there are provided a heat insulation layer 1, a first transition buffer structure 8 fixedly connected to the outer wall of the heat insulation layer 1, an inner side wall plate 3 fixedly connected to the outer wall of the first transition buffer structure 8, a radial filling structure 4 fixed to the outer wall of the inner side wall plate 3, and an outer side wall plate 5 fixedly connected to the outer wall of the radial filling structure 4.

[0286] Figure 8 The appearance of the tail gas pipeline is shown. Visibly, the external coating 7 has an external coating main body 701 and a protruding annular protrusion 702; a cross-section A1 - A1 is obtained by cutting along the midline of the annular protrusion 702. Figure 9a ; A cross-section A2 - A2 is obtained by cutting at any place of the external coating main body 701. Figure 9b .

[0287] As Figure 9a or Figure 9b shown, the tail gas pipeline further includes: an axial support structure 2 located inside the radial filling structure 4 and fixed to the outer wall of the inner side wall plate 3. There are 2 axial support structures 2, which are radially spaced apart in the tail gas pipeline.

[0288] As Figure 9a shown, the tail gas pipeline further includes: a radial support structure 6 fixed to the outer wall of the radial filling structure 4, and the axial support structure 2 passes through the radial support structure 6; there are 4 radial support structures 6, which are axially spaced apart in the tail gas pipeline; the axial support structure 2 is located inside the radial filling structure 4, is externally connected to the outer side wall plate 5, and the outer side wall plate 5 and the remaining sides of the radial support structure 6 are fixedly connected.

[0289] The internal filling structure 202 inside the axial support structure 2 is surrounded by an external reinforcement structure 203; each axial support structure 2 has three identical units fixedly connected and circumferentially arranged, and each unit has an internal filling structure 202.

[0290] In Figure 9a or Figure 9b , a cross-sectional view of the B2 - B2 section is obtained by axially cutting at the center of any axial support structure 2. Figure 10b ; A cross-sectional view of the B1 - B1 section is obtained by cutting at any position without an axial support structure 2. Figure 10a .

[0291] As Figure 10a shown, from the inside to the outside, there are provided in sequence: a heat insulation layer 1, an inner side wall plate 3, an axial support structure 2, a radial filling structure 4, an outer side wall plate 5, an external coating 7; the radial support structures 6 are axially spaced apart between the radial filling structure 4 and the outer side wall plate 5.

[0292] As Figure 10bAs shown in the figure, from the inside to the outside, there are successively arranged: a heat insulation layer 1, an inner side wall plate 3, an axial support structure 2, an outer side wall plate 5, and an external coating 7; the radial support structures 6 are distributed at intervals along the axial direction between the radial filling structure 4 and the outer side wall plate 5.

[0293] Furthermore, as Figure 7 shown in the figure, the first transition buffer structure 8 includes a first rigid connection layer 801, a first ductile support layer 802, and a second rigid connection layer 803 that are successively distributed from the high-temperature region to the low-temperature region; the first rigid connection layer 801, the first ductile support layer 802, and the second rigid connection layer 803 are connected by an adhesive.

[0294] As Figure 10a or Figure 10b shown in the figure, a second transition buffer structure 10 is provided between the outer side wall plate 5 and the radial support structure 6 or the radial filling structure 4. The outer side wall plate 5 and the radial support structure 6 are fixedly connected through the second transition buffer structure 10, and the outer side wall plate 5 and the radial filling structure 4 are fixedly connected through the second transition buffer structure 10. As Figure 15 shown in the figure, the second transition buffer structure 10 includes a third rigid connection layer 1001, a second ductile support layer 1002, and a fourth rigid connection layer 1003 that are successively distributed from the high-temperature region to the low-temperature region; the third rigid connection layer 1001, the second ductile support layer 1002, and the fourth rigid connection layer 1003 are connected by an adhesive. Among them, the third rigid connection layer 1001 is fixedly connected to the outer wall of the radial support structure 6 or the radial filling structure 4, and the fourth rigid connection layer 1003 is fixedly connected to the inner wall of the outer side wall plate 5.

[0295] The first rigid connection layer 801, the second rigid connection layer 803, the third rigid connection layer 1001, and the fourth rigid connection layer 1003 can be selected as fiberglass felts; for the fiberglass felts of the third rigid connection layer 1001 and the fourth rigid connection layer 1003, fiberglass felts with a fiber length of 15 mm have better flow guiding effects are selected; for the first rigid connection layer 801 and the second rigid connection layer 803, fiberglass felts with a fiber length of 5 mm are selected; the fiberglass felts are selected as chopped strands.

[0296] The first ductile support layer 802 and the second ductile support layer 1002 can be selected as fiberglass cloths; twill cloth, twill weave cloth, plain weave cloth, preferably twill cloth with good anti-shear and tensile properties, preferably 190 g / cm 3 twill cloth.

[0297] The adhesive includes: high-temperature resistant epoxy powder, high-temperature resistant toughening agent, and high-temperature resistant diluent; the high-temperature resistant epoxy powder can be selected as EH301 epoxy resin; the mass ratio of the amounts of the high-temperature resistant epoxy powder, the high-temperature resistant toughening agent, and the high-temperature resistant diluent is: 1:0.3:0.05. The high-temperature resistant toughening agent is selected as a commonly used alicyclic amine toughening agent, and the high-temperature resistant diluent is selected as a small molecule alicyclic epoxy.

[0298] Preferably, the expansion coefficient of the outer side wall panel 5 is 10.5×10 -6 m / °C, and the expansion coefficient of the material of the radial support structure 6 or the radial filling structure 4 is not greater than 40×10 -6 m / °C; the expansion coefficient of the heat insulation layer 1 is 0.15×10 -6 m / °C, and the expansion coefficient of the material of the inner side wall panel 3 is 7.5×10 -6 m / °C.

[0299] The matrix resin used for the heat insulation layer 1 is hybrid phenolic resin PF-45; the reinforcing fiber used for the heat insulation layer is carbon fiber. The form of the reinforcing material used for the heat insulation layer is fabric laminated needle punching.

[0300] The radial filling structure 4, the radial support structure 6, and the internal filling structure 202 use commercially available high-temperature resistant PEI (polyetherimide) foam with a porosity of 60%; the resins used for each part are shown in Table 1.

[0301] The thermal conductivity of the prepared heat insulation layer 1 is tested according to GB / T 3139-2005 "Test Method for Thermal Conductivity of Fiber Reinforced Plastics".

[0302] The shear strength of the inner side wall and the outer side wall is tested according to GB / T 1450.1-2005 "Test Method for Interlaminar Shear Strength of Fiber Reinforced Plastics", and the details are shown in Table 2.

[0303] Comparative Example 1

[0304] This example discloses a composite material tail gas pipeline system and its forming method. Compared with Example 1, the resin of the heat insulation layer is changed from hybrid phenolic resin PF-45 to EH301 epoxy resin, and the rest is the same as Example 1. The details are shown in Table 1.

[0305] Comparative Example 2

[0306] This example discloses a composite material tail gas pipeline system and its forming method. Compared with Example 1, the structure at the connection between the inner side wall and the heat insulation layer is changed from the structure of "glass fiber mat + glass fiber cloth + glass fiber mat" to "glass fiber mat + glass fiber mat", and the rest is the same as Example 1. The details are shown in Table 1.

[0307] Comparative Example 3

[0308] This example discloses a composite material tail gas pipeline system and its forming method. Compared with Example 1, when the outer side wall panel is formed, a conforming rubber is not provided at the fillet between the outer side wall panel and the radial support structure, and the rest is the same as Example 1. The details are shown in Table 1.

[0309] Table 1

[0310]

[0311]

[0312] Table 2

[0313] Experimental group Thermal conductivity / W / (mK) Inner wall shear strength / MPa Outer wall shear strength / MPa Example 1 0.066 60 70 Comparative example 1 0.078 - - Comparative example 2 - 55 60

[0314] In Example 1 of the present invention, a new IPC resin is used in the heat insulation layer. It can be ceramized on the surface at high temperature, harden and have a uniform nanoporous structure, with good heat insulation performance. Compared with the high-temperature resistant resins in the prior art, the heat insulation performance is greatly improved. Compared with Comparative Example 1, the thermal conductivity is reduced from 0.078 W / (mK) to 0.066 W / (mK), a decrease of 15.4%.

[0315] In Example 1 of the present invention, a structure of "glass fiber felt + glass fiber cloth + glass fiber felt" is adopted at the connection between the inner side wall and the heat insulation layer. Compared with Comparative Example 2 without glass fiber cloth, the shear strength of the inner / outer side walls is significantly improved. The shear strength of the inner side wall is increased from 55 MPa to 60 MPa, and the shear strength of the outer side wall is increased from 60 MPa to 70 MPa, with increases of 9.09% and 16.6% respectively.

[0316] At the same time, from the comparison of Figure 11 and Figure 12 it can be seen that after continuous use at 200 °C for 1000 h at the connection between the inner side wall plate and the heat insulation plate in Example 1, there is still no obvious cracking and stress peeling phenomenon; while in Comparative Example 2 at the connection between the inner side wall plate and the heat insulation plate, obvious cracking occurs under the same conditions (such as Figure 12 the circular marked area). The glass fiber cloth layer can produce a certain degree of "creep deformation" when subjected to external forces; the unique flexible structure of the glass fiber cloth greatly improves the stress difference and cracking caused by different expansion rates of the foam and the outer side wall plate during temperature changes, and overall forms a good stress buffer layer; and the glass fiber felt adjacent to the radial filling structure and the outer side wall plate are respectively tightly fixedly connected, effectively avoiding the defects of the glass fiber cloth body having insufficient strength and insufficient shear resistance.

[0317] At the same time, from the comparison of Figure 13 with Figure 14 it can be seen that in Example 1 of the present invention, due to the addition of follow-up rubber at the fillet of the outer side wall plate and the radial support structure, it has better appearance and less gum accumulation amount at the fillet of the radial support structure compared with Comparative Example 3 without added follow-up rubber.

[0318] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A composite tailpipe system, characterized in that, It includes an exhaust pipe unit (18) and a connection unit (17) provided at the axial end of the exhaust pipe unit for fixed connection of the exhaust pipe unit; The exhaust pipe unit (18) includes: an inner side wall plate (3), a radial filling structure (4), and an outer side wall plate (5) arranged in sequence from inside to outside; A radial support structure (6) is further provided between the radial filling structure (4) and the outer side wall plate (5); a second transition buffer structure (10) is further provided between the radial support structure (6), the radial filling structure (4), and the outer side wall plate (5); The radial support structure (6) is fixedly connected to the outer side wall plate (5) through the second transition buffer structure (10); The second transition buffer structure (10) is a multi-layer composite structure including a toughness support layer. The toughness support layer can match the radial support structure (6) and the outer side wall plate (5) with different thermal expansion coefficients, and the toughness support layer can match the radial filling structure (4) and the outer side wall plate (5) with different thermal expansion coefficients; The second transition buffer structure (10) includes a third rigid connection layer (1001), a second toughness support layer (1002), and a fourth rigid connection layer (1003) distributed in sequence from the high-temperature area to the low-temperature area; The third rigid connection layer (1001) is a glass fiber mat layer, the second toughness support layer (1002) is a glass fiber cloth layer, and the fourth rigid connection layer (1003) is a glass fiber mat layer.

2. The composite tail gas pipeline system according to claim 1, characterized in that The exhaust pipe further is provided with an axial support structure (2) parallel to the axial direction of the exhaust pipe. The axial support structure (2) is arranged inside the radial filling structure (4) and fixed to the outer wall of the inner side wall plate (3); the axial support structure (2) is multiple and is distributed at intervals along the circumferential direction of the exhaust pipe.

3. A composite tailpipe system according to claim 1, characterized in that, The connection unit (17) is provided with a fixed connection layer (1702) and a housing for fastening the exhaust pipe unit from inside to outside.

4. A composite tailpipe system according to claim 3, characterized in that, A sealing structure (1703) is provided along the outer wall of the exhaust pipe unit at one end where the housing abuts against the exhaust pipe unit.

5. A composite tail gas pipeline system according to claim 1, characterized in that, The difference in the coefficient of thermal expansion between the radial support structure (6) or the radial filling structure (4) and the outer side wall panel (5) is 35×10 -6 m / °C to 41×10 -6 m / °C.

6. A composite tail gas pipeline system according to claim 1, characterized in that, The glass fiber mat layer of the third rigid connection layer (1001) is 2 to 3 layers, the glass fiber cloth layer of the second toughness support layer (1002) is 1 to 3 layers, and the glass fiber mat layer of the fourth rigid connection layer (1003) is 2 to 3 layers.

7. The composite tail gas pipeline system according to claim 6, characterized in that, The fiber length of the glass fiber mat is 10 mm to 15 mm; the glass fiber mat is chopped strand; the glass fiber cloth is any one of twill cloth and plain cloth; the density of the glass fiber cloth is 170 g / cm 3 to 220 g / cm 3 Twill cloth.

8. A forming method for a composite tail gas pipeline system, characterized in that, A method for processing a composite material exhaust pipe system according to any one of claims 1-7, comprising the following steps: Step 1, vacuum infusion molding of the inner side wall plate: Using a vacuum infusion process to prepare an exhaust pipe preform with an inner side wall plate fixed on the outside; Step 2, forming of the axial support structure: Using an autoclave process to prepare the axial support structure in a mold; Step 3, assembling the inner side wall plate and the axial support structure: Fixing and connecting the axial support structure at a preset position of the inner side wall plate to obtain an exhaust pipe preform covered with the axial support structure; Step 4, fixing of the radial filling structure and the radial support structure: Bond and fix a radial filling structure on the outer wall of a prefabricated exhaust gas pipeline body covered with an axial support structure; bond and fix a radial support structure on the outer wall of the radial filling structure, and cure and form under vacuum to obtain a prefabricated exhaust gas pipeline body with a radial filling structure and a radial support structure; Step 5, lay a second transition buffer structure: Lay a second transition buffer structure on the outer wall of the prefabricated exhaust gas pipeline body with a radial filling structure; the second transition buffer structure (10) is a multi-layer composite structure including a ductile support layer, and the ductile support layer can match the radial support structure (6) with different coefficients of thermal expansion and the outer side wall plate (5), and the ductile support layer can match the radial filling structure (4) with different coefficients of thermal expansion and the outer side wall plate (5); The second transition buffer structure (10) includes a third rigid connection layer (1001), a second ductile support layer (1002) and a fourth rigid connection layer (1003) sequentially distributed from the high-temperature area to the low-temperature area; The third rigid connection layer (1001) is a glass fiber felt layer, the second ductile support layer (1002) is a glass fiber cloth layer, and the fourth rigid connection layer (1003) is a glass fiber felt layer; Step 6, form the outer side wall plate: Prepare the outer side wall plate on the outer wall of the second transition buffer structure by means of a vacuum infusion process; Step 7, connect the exhaust gas pipeline units: Take two exhaust gas pipeline units and install connection units at the ends of the exhaust gas pipeline units.

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