Preparation method of high-strength heat insulation pipe

Abstract

The invention relates to the field of preparation methods of heat insulation pipes, in particular to a preparation method of a high-strength heat insulation pipe. Putting the mixed raw materials into a double-screw extruder, detecting the resistance value of the fused material, and determining the stirring fusion condition of the material; under the unqualified condition, the temperature of the plasticizing section is adjusted, an extrusion opening is closed to flow into a backflow material opening, periodic stirring and fusion are conducted, under the qualified condition, the backflow opening is closed, the extrusion opening is opened to extrude an inner-layer pipeline, aerogel felt is wrapped and clamped, the second extrusion opening is used for secondarily wrapping and clamping an outer-layer pipeline, and the image acquisition and analysis module analyzes and judges whether the product is qualified or not; if not, the resistance value is adjusted, temperature detection is conducted on the fused material, the temperature difference of the plasticizing section is compared, and whether backflow exists or not is determined; the problems that in the prior art, the manufacturing process is uncontrollable, the temperature fluctuation of a traditional extrusion process is large, and waste is likely to be generated in the temperature adjusting process are solved.

Description

Technical Field

[0001] This invention relates to the field of composite pipe manufacturing technology, specifically a method for manufacturing high-strength thermal insulation pipes. Background Technology

[0002] With the escalating global energy crisis, the deepening of low-carbon and environmental protection concepts, and the continuous improvement of system energy efficiency requirements in industrial and civil sectors, the thermal insulation performance of pipe materials has been upgraded from an "additional requirement" to a "core indicator." The dual drive of technological progress and demand growth is propelling the pipe insulation field towards high performance, low energy consumption, long lifespan, and green technology. As a key carrier in energy transmission, HVAC, and industrial fluid transport, the thermal insulation performance of pipes directly affects system energy consumption, operating costs, and environmental benefits. Behind this upgraded demand is the combined effect of multiple factors; existing building insulation pipes mostly adopt a "inner pipe + insulation layer + outer protective pipe" structure.

[0003] Chinese Patent Publication No. CN116006785A discloses a low thermal conductivity, heat-insulating composite plastic pipe and its preparation method. The pipe has a three-layer structure, consisting of an inner layer, a middle layer, and an outer layer from the inside out. The middle layer contains modified diatomaceous earth to provide heat insulation. The preparation method involves first preparing the modified diatomaceous earth, then manufacturing granulated material for the middle layer, and finally co-extruding all the raw materials through a specially designed three-layer extrusion die to form a single, integrated structure. The middle layer material uses diatomaceous earth modified with a coupling agent and premixed with the same plastic resin as the inner and outer layers, ensuring complete integration between the middle layer and the inner and outer layers. The structure is a three-layer design, consisting of an inner layer, a middle layer, and an outer layer from the inside out. The middle layer contains modified diatomaceous earth, providing insulation. The manufacturing process involves first preparing the modified diatomaceous earth, then creating granules for the middle layer, and finally co-extruding all the layers together using a specially designed three-layer extrusion die. The middle layer material uses coupling agent-modified diatomaceous earth premixed with the same plastic resin as the inner and outer layers, ensuring complete integration between the middle and outer layers. This gives the pipeline not only excellent pressure resistance but also prevents delamination of the middle layer during use, thus extending the pipeline system's lifespan. However, this manufacturing process is uncontrollable; traditional extrusion processes experience large temperature fluctuations and are prone to generating waste during temperature adjustment. Summary of the Invention

[0004] Therefore, the present invention provides a method for preparing high-strength thermal insulation pipes to overcome the problems of uncontrollable manufacturing process, large temperature fluctuations in traditional extrusion processes, and easy generation of waste materials during temperature adjustment in the prior art.

[0005] To achieve the above objectives, the present invention provides a method for preparing a high-strength thermal insulation pipe. The technical solution adopted to achieve this objective is as follows: A method for preparing a high-strength thermal insulation pipe, characterized in that it includes: Pre-treat the raw materials to be mixed respectively according to a predetermined pre-treatment process, and mix them according to the material characteristics; Feed the mixed raw materials into a smoothly operating twin-screw extruder through predetermined feeding ports to heat and stir the mixed raw materials; Detect the resistance value of the fused material in the twin-screw extruder through a resistance sensing device set between the plasticizing section and the exhaust section, and determine the mixing and fusing situation of the material based on the detected resistance value; When it is determined that the mixing is unqualified based on the resistance value, adjust the temperature of the plasticizing section, and close the extrusion port so that the fused material flows into the return material port from the first return port for periodic stirring and fusing; When it is determined that the mixing is qualified based on the resistance value, close the return port and open the extrusion port; Extrude an inner layer pipe from the extrusion port, wrap the periphery of the extruded pipe with aerogel felt, and use a second extrusion port to perform secondary vacuum cladding on the pipe wrapped with aerogel felt to form an outer layer pipe; The image acquisition and analysis module acquires images of the extruded material; The image acquisition and analysis module analyzes the acquired image information and determines whether the state of the extruded pipe is qualified; When it is unqualified, adjust the resistance value, detect the temperature of the fused material, compare the temperature difference of the plasticizing section temperature, and determine whether to return; if not returning, adjust the temperature of the constant temperature zone and the extrusion port, and adjust the temperature change rate; When the image acquisition and analysis module determines it is qualified, the second extrusion port continuously extrudes the pipe.

[0006] Furthermore, the process of determining the mixing and fusing situation of the material based on the detected resistance value includes, Compare the detected resistance value with a predetermined primary resistance value range interval, Determine that the mixing is qualified based on the detected resistance value falling within the predetermined primary resistance value range interval; Determine that the mixing is unqualified based on the detected resistance value not falling within the predetermined primary resistance value range interval.

[0007] Furthermore, when it is determined that the mixing is unqualified based on the resistance value and the detected resistance value is greater than the primary resistance value range interval, the control module determines that the hardness of the mixed material does not meet the extrusion requirement, and controls the temperature of the plasticizing section to increase, where the increased temperature value of the plasticizing section is related to the numerical range of the detected resistance value not falling within the primary resistance value range interval.

[0008] Furthermore, when it is determined that the mixing is unqualified based on the resistance value and the detected resistance value is less than the primary resistance value range interval, the control module determines that the mixed material is too soft to meet the extrusion requirement, and controls the temperature of the plasticizing section to decrease, Among them, the decrease in temperature during the plasticizing stage is related to the fact that the detected resistance value does not fall within the range of the primary resistance value.

[0009] Furthermore, the process of adjusting the temperature in the plasticizing zone is determined based on the pipe surface after initial extrusion. The acquired image information is compared with the first defect image information set and the second defect image information set respectively: If the collected image information matches the first defect image information set, it is determined that the extruded material has too high hardness. If the collected image information matches the second defect image information set, it is determined that the extruded material has too low hardness. The image information in the first defect image information set includes surface roughness, ripples, and cracks.

[0010] The image information in the second defect image information set includes dimensional deformation and color change.

[0011] Furthermore, based on the collected image information matching the first defect image information set, the degree of defect of the extruded material is determined by the image, and the range of the predetermined primary resistance value range is redefined according to the determination result. The extrusion port is closed and the second reflux port is opened for reflux. The extrusion port is opened when the extruded material meets the new resistance value range.

[0012] Furthermore, the process of redefining the range of the predetermined primary resistance value range based on the collected image information conforming to the first defect image information set includes: The adjustment value for the range is determined based on the degree of defect in the extruded material. The baseline point for adjustment is determined based on the detected resistance value; The midpoint of the range determined by combining the adjustment value and the baseline point; The new range is determined based on the midpoint of the previous range.

[0013] Furthermore, the degree of defect in the extruded material is determined based on a comprehensive assessment of the defect types in the acquired image information; Different defect levels have different weights in determining the degree of defect.

[0014] Furthermore, the size of the range interval is related to the value of the midpoint of the range interval. Within a certain range of values, the size of the range interval is positively correlated with the midpoint of the range interval.

[0015] Furthermore, when adjusting the temperature of the constant temperature zone and the extrusion outlet, it is necessary to adjust the rate of change of the temperature of the constant temperature zone and the extrusion outlet according to the rotation speed.

[0016] Compared with existing technologies, the beneficial effects of this invention are that traditional extrusion processes suffer from large temperature fluctuations and are prone to generating waste during temperature adjustment. This invention completely solves this problem through the following design: The invention collects resistance data to monitor the resistance value during material mixing and fusion in real time, and compares the collected value with a preset range through a control module. Based on the resistance value deviation, the temperature is precisely adjusted. This intelligent control mechanism linking resistance and temperature can correct temperature fluctuations in real time. Compared with the traditional extrusion process in the comparison patent that lacks real-time feedback, this significantly improves process controllability and reduces waste caused by temperature fluctuations from the source.

[0017] Furthermore, the recirculation module of this invention can more effectively reduce waste generation during the production process because... Further temperature adjustments result in excessive waste. If the waste is to be recycled after extrusion, it requires further processing, which wastes manpower and resources. Therefore, if a problem is found during the extrusion process, the waste can be recycled directly, reducing the cost of processing extrusion waste and making it more cost-effective than traditional processes.

[0018] Furthermore, the intermediate insulation layer of this invention uses aerogel felt. The porous structure of the aerogel felt can limit the damage range (avoiding overall failure), and the high-strength materials of the inner and outer layers can reduce the spread of damage, resulting in lower maintenance costs.

[0019] Furthermore, in this invention, adjustment values ​​are set according to the defect level, and the adjustment values ​​are used to divide the scoring level and determine the adjustment range of the primary resistance value range. This allows for more precise temperature control, reduces the material defect rate, and is more environmentally friendly and efficient, greatly improving the working efficiency of the extruder. Attached Figure Description

[0020] Appendix Figure 1 This is a schematic diagram of an assembly line for a high-strength thermal insulation pipe manufacturing method according to an embodiment of the present invention. Appendix Figure 2 This is a schematic diagram illustrating the function of a production line component in a high-strength thermal insulation pipe manufacturing method according to an embodiment of the present invention. Appendix Figure 3 This is a schematic flowchart illustrating a method for preparing a high-strength thermal insulation pipe according to an embodiment of the present invention. Appendix Figure 4 This is a schematic diagram illustrating the adjustment process based on the image acquisition and analysis module in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0024] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Please see Figures 1-4 As shown, Figure 1 This is a schematic diagram of the production line for the high-strength heat-insulating pipe preparation method of the present invention. When preparing the pipe using the high-strength heat-insulating pipe preparation method of the present invention, the following components are provided: inlet 1, plasticizing section 2, return inlet 3, resistance sensing device 4, first return inlet 5, exhaust section 6, constant temperature zone 7, temperature detection module 8, second return inlet 9, extrusion port 10, clamping module 11, second extrusion port 12, and image acquisition and analysis module 13. Figure 2 This is a schematic diagram illustrating the function of components in a method for preparing a high-strength thermal insulation pipe according to an embodiment of the present invention; Figure 3 This is a schematic flowchart of a method for preparing a high-strength thermal insulation pipe according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the adjustment process based on the image acquisition and analysis module in an embodiment of the present invention.

[0026] To achieve the above objectives, the present invention provides a method for preparing a high-strength thermal insulation pipe, the method comprising: Step 1: Pre-treat the raw materials to be mixed according to the predetermined pre-treatment process, and then mix them according to their material properties, dividing them into three parts, which are denoted as Mixed Material A, Mixed Material B, and Mixed Material C. Step 2: Preheat the twin-screw extruder to 150 degrees Celsius and 50 rpm. Once the preheating temperature is reached, add the following materials in sequence: put mixed material A into the leftmost feed port, add mixed material B into the middle feed port to increase the material tension, and add mixed material C into the rightmost feed port. Raise the temperature to 180 degrees Celsius for plasticizing.

[0027] Step 3: There is a resistance sensing device between the plasticizing section and the exhaust section. The mixing and blending of the internal materials is determined based on the range of the initial resistance value.

[0028] The control module has a preset range of primary resistance values. The control module compares the resistance value collected by the resistance sensing device with the range of primary resistance values.

[0029] The primary resistance value range is 120-150 N·m.

[0030] Step 4: If the collected resistance value falls within the range of the primary resistance value, it is determined that the material mixing and fusion in the extruder is qualified, and the extrusion module is turned on to extrude the fused material.

[0031] Step 5: Extrude the inner tube through the extrusion port, and wrap the extruded tube with aerogel felt. The aerogel felt is 5mm thick. The second extrusion port performs a second vacuum wrapping of the outer tube with the aerogel felt. Step 6: The image acquisition and analysis module analyzes the acquired image information to determine whether the output material is qualified. If the image acquisition and analysis module determines that it is qualified, the second extrusion port continues to extrude material.

[0032] In step 1, the pretreatment process for each mixed material includes, Mixed Material A: Add glass fiber (3 parts), polypropylene resin (5 parts), and high flame retardant polyethylene (7 parts) to a ball mill and ball mill at 300 rpm for 45 minutes to obtain a uniformly mixed granular mixture.

[0033] Mixed Material B: Nano-silica (1.0 part) and perlite (0.3 part) are pulverized by an air jet mill, and the median particle size is controlled to be 2 μm to obtain an ultrafine powder mixture.

[0034] Mixed material C: Add calcium-zinc composite heat stabilizer (0.8 parts) and trimellitic acid (0.4 parts) to an ultrasonic dispersion device and ultrasonically disperse at 600W power for 15 minutes to obtain a uniform liquid dispersion system.

[0035] If the collected resistance value does not fall within the range of the primary resistance value, the mixing and fusion of materials in the plasticizing section is deemed unqualified, and the working process is determined based on the unqualified situation.

[0036] The temperature adjustment range of the plasticizing section is determined based on the range of resistance values ​​that are greater than the primary resistance value. The difference between the collected resistance value and the range of the primary resistance value is calculated and recorded as the first resistance difference. The temperature rise in the plasticizing section is determined based on this first resistance difference. The settings are as follows: If the first resistance difference is greater than or equal to 20 N·m, then the temperature rise value is determined to be 10 degrees. If the first resistance difference is greater than or equal to 10 N·m and less than 20 N·m, then the temperature rise is determined to be 5 degrees. If the first resistance difference is greater than or equal to 5 N·m and less than 10 N·m, then the temperature rise is determined to be 3 degrees. If the first resistance difference is greater than or equal to 1 N·m and less than 5 N·m, then the temperature rise is determined to be 1 degree. If the collected resistance value is greater than the range of the primary resistance value, it is determined that the material fusion and mixing is insufficient. The extrusion module is closed and the first reflux port is opened so that the unqualified fused material is returned from the reflux device to the reflux port for reheating and stirring. The temperature adjustment range of the plasticizing section is determined based on the range of resistance values ​​collected that are less than the primary resistance value. The difference between the collected resistance value and the range of the primary resistance value is calculated and recorded as the second resistance difference. The temperature reduction value of the plasticizing section is determined based on the value of the second resistance difference. If the second resistance difference is greater than or equal to 20 N·m, then the cooling value is determined to be 10 degrees. If the second resistance difference is greater than or equal to 10 N·m and less than 20 N·m, then the temperature drop is determined to be 5 degrees Celsius. If the second resistance difference is greater than or equal to 5 N·m and less than 10 N·m, then the temperature drop is determined to be 3 degrees. If the second resistance difference is greater than or equal to 1 N·m and less than 5 N·m, then the temperature drop is determined to be 1 degree. If the collected resistance value is less than the range of the primary resistance value, it is determined that the material is too soft. The extrusion module is closed and the reflux device of the first reflux port is opened so that the unqualified fused material is returned to the reflux port to be cooled and stirred again. The upper limit of the temperature in the plasticizing section is 220 degrees Celsius.

[0037] Based on the current resistance value being within the range of the initial resistance value, it is determined that the material fusion and mixing is qualified and it can be extruded through the extrusion port; The clamping module clamps the aerogel felt with a thickness of 5mm in the extruded inner layer material and conveys it to the second extrusion port. The temperature of the second extrusion port is kept synchronized with that of the extrusion port. The second extrusion port clamps the outer layer pipe of the wrapped aerogel felt and draws a vacuum inside, forming a "inner layer-aerogel-outer layer" composite structure.

[0038] Vacuum degree ≥ -0.1MPa Quantization process in the image acquisition and analysis module; The processed plastic pipes are photographed vertically to ensure a complete view of their axial, radial, and end-face morphology. Image processing software is used for noise reduction (Gaussian filtering), contrast enhancement, and edge detection (Canny algorithm) to highlight the contour features of defective areas.

[0039] The first set of defect image information includes surface roughness, ripples, and cracks.

[0040] Surface roughness, ripples, and cracks are assessed for their severity through image analysis, requiring a combination of visual feature quantification and grading threshold settings. The specific methods and four-level classification criteria are as follows: Defect Feature Extraction and Four-Level Classification Criteria (a) Surface roughness: Determination based on texture uniformity and grain size Surface roughness manifests as irregular bumps, particles, or pits on the surface of the pipe. The core quantitative indicators include roughness texture index (based on grayscale change frequency), average particle size, and the proportion of rough areas.

[0041] Acceptable standard: Surface roughness Ra≤0.8μm.

[0042] (ii) Surface ripples: Determination based on periodic fluctuations ; Corrugations are characterized by periodic wave-like undulations on the surface of pipes along the axial or circumferential direction. The core quantitative indicators include wave height (maximum undulation height), wavelength (period length), and corrugation coverage ratio.

[0043]

[0044] (iii) Surface fracture: Integrity assessment based on cracks / holes Rupture includes surface cracks, fissures, or holes. Key quantitative indicators include crack length / width, hole diameter, number of ruptures, and whether they penetrate the pipe wall.

[0045]

[0046] The image acquisition and analysis module determines the first defect adjustment coefficient based on various defect levels within the first defect image information set. The adjustment base value is set as follows: 1 for minor defects, 2 for low-level defects, 3 for moderate defects, and 5 for severe defects. The first defect adjustment coefficient is set as K1, K1 = (A1×b1)×1 + (A2×b2)×2 + (A3×b3)×3 + (A4×b4)×5; Wherein, A1 is the number of defects identified as minor defects in the acquired images, A2 is the number of defects identified as low-grade defects in the acquired images, A3 is the number of defects identified as moderate-grade defects in the acquired images, A4 is the number of defects identified as severe-grade defects in the acquired images, b1 is the compensation parameter for calculating the number of minor defects to the first defect adjustment coefficient, b2 is the compensation parameter for calculating the number of low-grade defects to the first defect adjustment coefficient, b3 is the compensation parameter for calculating the number of moderate-grade defects to the first defect adjustment coefficient, and b4 is the compensation parameter for calculating the number of severe-grade defects to the first defect adjustment coefficient.

[0047] Set b1=1, b2=0.8, b3=0.9, b4=1; When determining the degree of defect, collecting data on different types of defects comprehensively reflects the degree of defect, making the defect determination more accurate. In particular, in one case, the extruded material may meet the roughness standard but have cracks. In this case, it indicates that the extruded material is too hard and cannot be extruded into a shape. However, due to the material properties and the lubrication of the equipment, it still meets the roughness standard even with cracks. In another case, the surface roughness of the extruded material does not meet the standard but there are no cracks on the surface. This situation may be caused by friction between the excessively hard material and the extrusion nozzle. In yet another case, the surface of the extruded material has ripples but no cracks on the surface. This situation may be caused by the excessively hard material being accumulated due to hard extrusion.

[0048] Therefore, it can be seen that the surface defects of excessively hard extruded materials vary under different material and equipment conditions. By collecting and comprehensively calculating various surface defects, the defect judgment can be made more accurate.

[0049] Furthermore, for any type of defect, its degree is classified, and a first defect adjustment coefficient that comprehensively reflects the overall material defect degree is calculated based on the degree corresponding to each defect. The defect judgment is made more intuitive through data display.

[0050] Specifically, determining the compensation parameters for calculating the adjustment coefficient of the first defect can intuitively calculate the current adjustment value of the defect, enabling more precise control.

[0051] Meanwhile, the scoring criteria for calculating the first defect adjustment coefficient vary for different single curve levels, ensuring the relevance of the calculation and enhancing the accuracy of the data.

[0052] The adjustment value for the range interval is determined by the value of the first defect adjustment coefficient K1. If the value of the first defect adjustment coefficient K1 is less than or equal to the first adjustment evaluation baseline value, then the adjustment value of the range interval is determined to be the first adjustment value. If the value of the first defect adjustment coefficient K1 is greater than the first adjustment evaluation baseline value and less than or equal to the second adjustment evaluation baseline value, then the adjustment value of the range interval is determined to be the second adjustment value. If the value of the first defect adjustment coefficient K1 is greater than the second adjustment evaluation baseline value, then the adjustment value of the range interval is determined to be the third adjustment value. The setting is that the first adjustment value is less than the second adjustment value, which is less than the third adjustment value; The midpoint of the range is determined by subtracting the corresponding adjustment value from the detected resistance value. Determine the range interval based on the magnitude of the midpoint of the range interval. If the median value of the range interval is greater than the minimum interval evaluation value and less than the maximum interval evaluation value, then the range interval is determined based on the proportional relationship. If the median value of the range interval is less than the minimum interval evaluation value, then the range interval is determined based on the minimum interval range value.

[0053] The base value for the first adjustment evaluation is set to 2, and the base value for the second adjustment evaluation is set to 4. When determining different adjustment values, the primary resistance value range is adjusted by dividing the adjustment value, and the current resistance value range is redefined to ensure the accuracy of the adjustment and enable more precise temperature control.

[0054] If the material after initial extrusion is determined to belong to any of the defect levels in the first defect image information set, the range of the primary resistance value needs to be redefined. When the first adjustment value is met, the resistance value is reduced by 1 N·m, and the range of the primary resistance value is adjusted. The current value is the middle value, and the current temperature of the plasticizing zone is adjusted according to the first resistance difference.

[0055] When the second adjustment value is met, the resistance value is reduced by 5 N·m, and the range of the primary resistance value is adjusted. The current value is the middle value, and the current temperature of the plasticizing zone is adjusted according to the first resistance difference.

[0056] When the third adjustment value is met, the resistance value is reduced by 10 N·m, and the range of the primary resistance value is adjusted. The current value is the middle value, and the current temperature of the plasticizing zone is adjusted according to the first resistance difference.

[0057] The maximum adjustable temperature is: the temperature range of the initial plasticizing zone should not exceed 40 degrees Celsius.

[0058] The second set of defect image information includes size deformation and color change.

[0059] II. Four-level classification standard for defect severity Based on industry processing precision requirements, the severity of defects is classified into four categories: minor, low, moderate, and severe. The specific quantitative standards are as follows:

[0060] The image acquisition and analysis module determines the second defect adjustment coefficient based on various defect levels within the second defect image information set. The adjustment base value is set as follows: 1 for minor defects, 2 for low-level defects, 3 for moderate defects, and 5 for severe defects. The second defect adjustment coefficient is set as K2, K2=(c1×d1)×1+(c2×d2)×2+(c3×d3)×3+(c4×d4)×5; Wherein, c1 is the number of defects identified as minor defects in the acquired images, c2 is the number of defects identified as low-grade defects in the acquired images, c3 is the number of defects identified as moderate-grade defects in the acquired images, c4 is the number of defects identified as severe-grade defects in the acquired images, d1 is the compensation parameter for calculating the number of minor defects to the second defect adjustment coefficient, d2 is the compensation parameter for calculating the number of low-grade defects to the second defect adjustment coefficient, d3 is the compensation parameter for calculating the number of moderate-grade defects to the second defect adjustment coefficient, and d4 is the compensation parameter for calculating the number of severe-grade defects to the first defect adjustment coefficient.

[0061] When determining the degree of defect, collecting data on different types of defects and comprehensively reflecting the degree of defect makes the defect determination more accurate. In particular, in one case, the extruded material may meet the size standard but have discoloration. In this case, it indicates that the temperature of the extruded material is too high. Due to the rapid cooling of the extruded material at the extrusion nozzle and the slight degradation, it still meets the size standard. In another case, the extruded material is deformed in size but there is no discoloration on the surface. The reason for this situation may be that the temperature is not high enough to cause the material to discolor. Under different material conditions and equipment conditions, the surface defects of excessively hard extruded materials will vary. By collecting data on various surface defects and comprehensively calculating them, the defect determination becomes more accurate.

[0062] Furthermore, for any type of defect, its degree is classified, and a second defect adjustment coefficient that comprehensively reflects the overall material defect degree is calculated based on the degree corresponding to each defect. The defect judgment is made more intuitive through data display.

[0063] Specifically, determining the compensation parameters for calculating the second defect adjustment coefficient allows for a more intuitive calculation of the current adjustment value of the defect, enabling more precise control.

[0064] Meanwhile, the scoring criteria for calculating the second defect adjustment coefficient vary for different single curve levels, ensuring the relevance of the calculation and enhancing the accuracy of the data.

[0065] The adjustment value for the range interval is determined by the value of the second defect adjustment coefficient K2. If the value of the second defect adjustment coefficient K2 is less than or equal to the first adjustment evaluation baseline value, then the adjustment value of the range interval is determined to be the first adjustment value. If the value of the second defect adjustment coefficient K2 is greater than the first adjustment evaluation baseline value and less than or equal to the second adjustment evaluation baseline value, then the adjustment value of the range interval is determined to be the second adjustment value. If the value of the second defect adjustment coefficient K2 is greater than the second adjustment evaluation baseline value, then the adjustment value of the range interval is determined to be the third adjustment value. The setting is that the first adjustment value is less than the second adjustment value, which is less than the third adjustment value; The midpoint of the range is determined by subtracting the corresponding adjustment value from the detected resistance value. Determine the range interval based on the magnitude of the midpoint of the range interval. If the median value of the range interval is greater than the minimum interval evaluation value and less than the maximum interval evaluation value, then the range interval is determined based on the proportional relationship. If the median value of the range interval is less than the minimum interval evaluation value, then the range interval is determined based on the minimum interval range value.

[0066] Set b1=1, b2=0.8, b3=0.9, b4=1 Set the base value for the first adjustment evaluation to 2, and the base value for the second adjustment evaluation to 4.

[0067] Specifically, when determining different adjustment values, the primary resistance value range is adjusted by dividing the adjustment value, and the current resistance value range is redefined to ensure the accuracy of the adjustment and enable more precise temperature control.

[0068] If the material after initial extrusion is determined to belong to any of the defect levels in the second defect image information set, the range of the primary resistance value needs to be redefined. When the second adjustment value is met, the resistance value increases by 1 N·m, and the range of the primary resistance value is adjusted. The current value is the middle value, and the current temperature of the plasticizing zone is adjusted according to the second resistance difference.

[0069] When the second adjustment value is met, the resistance value increases by 5 N·m, and the range of the primary resistance value is adjusted. The current value is the middle value, and the current temperature of the plasticizing zone is adjusted according to the second resistance difference.

[0070] When the third adjustment value is met, the resistance value increases by 10 N·m, and the range of the primary resistance value is adjusted. The current value is the middle value, and the current temperature of the plasticizing zone is adjusted according to the second resistance difference.

[0071] The maximum adjustable temperature is: the temperature range of the initial plasticizing zone should not exceed 20 degrees Celsius.

[0072] For fused materials that have failed the temperature test in the plasticizing section, a temperature detection device is used to monitor the temperature of the fused materials.

[0073] The initial constant temperature zone temperature range is set 5-10 degrees lower than the current plasticizing zone temperature.

[0074] The initial extrusion outlet temperature range is set 10-20 degrees lower than the initial constant temperature zone temperature.

[0075] If the current temperature of the fusion material is more than 10 degrees higher than the upper limit of the current plasticizing section temperature range, it is not adjustable.

[0076] When the current temperature of the fusion material is more than 10 degrees higher than the lower limit of the current plasticizing section temperature range, it is not adjustable.

[0077] When the current temperature of the fusion material is less than or equal to 10 degrees Celsius above the upper limit of the current plasticizing section temperature range, it is within the adjustable range.

[0078] When the current temperature of the fusion material is less than or equal to 10 degrees Celsius below the lower limit of the current plasticizing section temperature range, it is within the adjustable range.

[0079] When the current temperature of the fusion material is within the unadjustable range, the extrusion port is closed, and the second return port inside the extrusion port is opened, allowing unqualified fusion material to flow back to the return module.

[0080] When the fused material is within the adjustable range, the control module controls the temperature regulation of the constant temperature zone and the extrusion port.

[0081] When the fused material is within an adjustable range, the difference between the collected temperature and the value within the current plasticizing temperature range is recorded as the first temperature difference. This is denoted as the first temperature difference. Based on this first temperature difference, the temperature drop between the initial isothermal zone temperature and the initial extrusion outlet temperature is determined. The settings are as follows: If the first temperature difference is less than or equal to 10 degrees and greater than 6 degrees, the lower limit of the initial constant temperature zone temperature range and the lower limit of the initial extrusion outlet temperature range will be reduced by 10 degrees.

[0082] If the first temperature difference is less than or equal to 6 degrees and greater than 3 degrees, the lower limit of the initial constant temperature zone temperature range and the lower limit of the initial extrusion outlet temperature range will be reduced by 5 degrees.

[0083] If the first temperature difference is less than or equal to 3 degrees and greater than 1 degree, the lower limit of the initial constant temperature zone temperature range and the lower limit of the initial extrusion outlet temperature range will be reduced by 3 degrees.

[0084] If the first temperature difference is less than or equal to 1 degree, then the temperature drop value is determined to be 1 degree.

[0085] When the fused material is within an adjustable range, the difference between the collected temperature and the temperature range within the current plasticizing section is recorded as the second temperature difference. The temperature rise values ​​of the initial isothermal zone and the initial extrusion outlet temperature are determined based on the value of the second temperature difference. The settings are as follows: If the second temperature difference is less than or equal to 10 degrees and greater than 6 degrees, the lower limit of the initial constant temperature zone temperature range and the lower limit of the initial extrusion outlet temperature range will be increased by 10 degrees.

[0086] If the second temperature difference is less than or equal to 6 degrees and greater than 3 degrees, the lower limit of the initial constant temperature zone temperature range and the lower limit of the initial extrusion outlet temperature range will be increased by 5 degrees.

[0087] If the second temperature difference is less than or equal to 3 degrees and greater than 1 degree, the lower limit of the initial constant temperature zone temperature range and the lower limit of the initial extrusion outlet temperature range will be increased by 3 degrees.

[0088] If the second temperature difference is less than or equal to 1 degree, then the temperature rise is determined to be 1 degree.

[0089] For materials that have entered the constant temperature zone, the time required to determine the temperature change based on the screw rotation speed needs to be set. When the screw speed is greater than or equal to 30 rpm and less than 40 rpm, the constant temperature zone is adjusted to change every 0 seconds, and the extrusion outlet temperature is adjusted every 3 seconds.

[0090] When the screw speed is greater than or equal to 40 rpm and less than 50 rpm, the constant temperature zone is adjusted to change within 0 seconds, and the extrusion outlet temperature is adjusted within 2.6 seconds.

[0091] When the screw speed is greater than or equal to 50 rpm and less than 60 rpm, the constant temperature zone is adjusted to change within 0 seconds, and the extrusion outlet temperature is adjusted within 2.3 seconds.

[0092] When the screw speed is greater than or equal to 70 rpm and less than 80 rpm, the constant temperature zone is adjusted to change within 0 seconds, and the extrusion outlet temperature is adjusted within 2 seconds.

[0093] The maximum rotational speed of the screw is 80 rpm.

[0094] By comparing the temperature of the fused material with the current temperature of the plasticizing section, it is possible to more accurately determine whether the fused material is suitable for extrusion, thus avoiding the waste of resources caused by extruding substandard materials.

[0095] Specifically, when the temperature of the fusion material is set to an adjustable range or a non-adjustable range, setting an upper limit for the temperature of the fusion material can more effectively control the pass rate.

[0096] Specifically, when the fused material is within an adjustable range, adjusting the temperature rise and fall of the constant temperature zone and the extrusion port based on the temperature difference can save more control time.

[0097] Specifically, by adjusting the temperature change time of the constant temperature zone and the extrusion port according to the rotation speed, the temperature of the fusion material can be controlled more precisely, allowing the material to be heated or cooled more accurately when entering the current area, thus avoiding incorrect adjustment of the qualified fusion material temperature.

[0098] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength thermal insulation pipe, characterized in that, Including: Pre-treat the raw materials to be mixed respectively according to a predetermined pre-treatment process, and mix them according to the material characteristics; Feed each mixed raw material into a smoothly operating twin-screw extruder through a predetermined feeding port (1) to heat and stir each of the mixed raw materials; Detect the resistance value of the fused material in the twin-screw extruder through a resistance sensing device (4) arranged between the plasticizing section (2) and the exhaust section (6), and determine the mixing and fusing condition of the material based on the detected resistance value; When it is determined that the mixing is unqualified based on the resistance value, adjust the temperature of the plasticizing section (2), and close the extrusion port (10) so that the fused material flows from the first reflux port (5) into the reflux material port (3) for periodic stirring and fusing; When it is determined that the mixing is qualified based on the resistance value, close the reflux port and open the extrusion port (10); The extrusion port (10) extrudes an inner layer pipe, wrap the periphery of the extruded pipe with aerogel felt, and the second extrusion port (12) performs secondary vacuum clamping on the pipe wrapped with aerogel felt to form an outer layer pipe; The image acquisition and analysis module (13) performs image acquisition on the extruded material; The image acquisition and analysis module (13) analyzes the acquired image information and determines whether the state of the extruded pipe is qualified; When it is unqualified, adjust the resistance value, detect the temperature of the fused material, compare the temperature difference of the plasticizing section (2), and determine whether to reflux; when there is no reflux, adjust the temperature of the constant temperature zone (7) and the extrusion port (10), and adjust the temperature change speed; When the image acquisition and analysis module (13) determines that it is qualified, the second extrusion port (12) continuously extrudes the pipe.

2. The method for preparing a high-strength heat-insulating and heat-preserving pipe according to claim 1, wherein The process of determining the mixing and fusing condition of the material based on the detected resistance value includes Comparing the detected resistance value with a predetermined primary resistance value range interval Determining that the mixing is qualified based on the detected resistance value falling within the predetermined primary resistance value range interval; Determining that the mixing is unqualified based on the detected resistance value not falling within the predetermined primary resistance value range interval.

3. The method for preparing a high-strength heat-insulating and heat-preserving pipe according to claim 2, wherein When it is determined that the mixing is unqualified based on the resistance value and the detected resistance value is greater than the primary resistance value range interval, the control module determines that the hardness of the mixed material does not meet the extrusion requirement, and controls the temperature of the plasticizing section (2) to increase Wherein, the increased temperature value of the plasticizing section (2) is related to the numerical range in which the detected resistance value does not fall within the primary resistance value range interval.

4. The method for preparing a high-strength heat-insulating and heat-preserving pipe according to claim 2, wherein When it is determined that the mixing is unqualified based on the resistance value and the detected resistance value is less than the primary resistance value range interval, the control module determines that the mixed material is too soft and does not meet the extrusion requirement, and controls the temperature of the plasticizing section (2) to decrease Wherein, the decreased temperature value of the plasticizing section (2) is related to the numerical range in which the detected resistance value does not fall within the primary resistance value range interval.

5. The method for preparing a high-strength heat-insulating and heat-preserving pipe according to claim the process of determining the adjustment of the plasticizing zone temperature based on the surface of the pipe after initial extrusion ​ The acquired image information is compared with the first defect image information set and the second defect image information set respectively: If the collected image information matches the first defect image information set, it is determined that the extruded material has too high hardness. If the collected image information matches the second defect image information set, it is determined that the extruded material has too low hardness. The image information in the first defect image information set includes surface roughness, ripples, and cracks; The image information in the second defect image information set includes dimensional deformation and color change.

6. The method for preparing a high-strength thermal insulation pipe according to claim 5, characterized in that, Based on the collected image information conforming to the first defect image information set, the degree of defect of the extruded material is determined by the image, and the range of the predetermined primary resistance value range is redefined according to the determination result. The extrusion port (10) is closed and the second return port (9) is opened for return. When the extruded material meets the new resistance value range, the extrusion port (10) is opened.

7. The method for preparing a high-strength thermal insulation pipe according to claim 6, characterized in that, The process of redefining the range of the predetermined primary resistance value range based on the collected image information conforming to the first defect image information set includes: The adjustment value for the range is determined based on the degree of defect in the extruded material. The baseline point for adjustment is determined based on the detected resistance value; The midpoint of the range determined by combining the adjustment value and the baseline point; The new range is determined based on the midpoint of the previous range.

8. The method for preparing a high-strength thermal insulation pipe according to claim 7, characterized in that, The degree of defect in the extruded material is determined based on the defect types in the acquired image information. Different defect levels have different weights in determining the degree of defect.

9. The method for preparing a high-strength thermal insulation pipe according to claim 8, characterized in that, The size of the range interval is related to the value of the midpoint of the range interval. Within a certain range of values, the size of the range interval is positively correlated with the midpoint of the range interval.

10. The method for preparing a high-strength thermal insulation pipe according to claim 7, characterized in that, When adjusting the temperature of the constant temperature zone (7) and the extrusion port (10), the rate of temperature change of the constant temperature zone (7) and the extrusion port (10) needs to be adjusted according to the rotation speed.

Images