Temperature damage detection method and temperature measuring device based on optimized vacuum sintering furnace

Abstract

This application proposes a temperature damage detection method and temperature measuring device based on an optimized vacuum sintering furnace, belonging to the field of heat transfer. The method includes: optimizing the structure of the vacuum sintering furnace using different insulation structures to derive a one-dimensional performance simulation model of the carbon felt insulation layer; based on the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve, and the workpiece temperature, calculating the range of carbon felt insulation layer thickness at different sintering temperatures using inverse simulation principles, and then using forward simulation to obtain the optimal carbon felt insulation layer thickness within the range of thickness values ​​at different sintering temperatures; using the optimal carbon felt insulation layer thickness as the length of the temperature measuring device, constructing a temperature measuring device for the vacuum sintering furnace, and measuring the temperature of the vacuum sintering furnace using multiple temperature measuring devices; obtaining the temperature damage detection result based on the measurement results. This method solves the problem that the temperature within the effective heating zone after structural optimization cannot be directly measured due to excessively high temperatures.

Description

Technical Field

[0001] This invention belongs to the field of heat transfer, specifically relating to a method and device for detecting temperature damage in an optimized vacuum sintering furnace. Background Technology

[0002] Vacuum sintering technology combines vacuum technology with sintering processes, enabling significant improvements in the properties of metallic materials and workpieces. Vacuum sintering furnaces are key equipment in the production of special powder metallurgy and ceramic products, with furnace temperature uniformity being a primary indicator of the furnace's heating performance. The structure of the insulation system significantly impacts furnace temperature uniformity, and the heat shield, its core component, is entirely located within the furnace chamber. It prevents heat loss, reduces temperature differences within the furnace, and thus plays a crucial role in improving the temperature uniformity of the vacuum sintering furnace.

[0003] However, simulations of the improvement in insulation performance after adopting different insulation structures are generally conducted based on the original (unoptimized) equipment. This means only experimental data for the original equipment is available, not experimental data after adopting the new structure. Consequently, when predicting the performance parameters of the sintering furnace after using the optimized structure, there is no accurate one-dimensional data model for the temperature drop of the heat insulation screen. Furthermore, the heat insulation screen structure has a significant impact on the temperature control and heat loss of the sintering furnace, and the most suitable heat insulation screen equipment parameters are not matched based on the material output results.

[0004] If the insulation layer of a vacuum sintering furnace is set too thick or too thin during operation, it may affect the yield of finished products and the service life of the equipment, while also greatly increasing energy consumption.

[0005] When sintering materials in a vacuum sintering furnace, the sintering temperature fluctuates within a certain range due to slight differences in the structure of the workpieces, resulting in significant fluctuations in the product yield. The parameters of the furnace's heat insulation screen are generally fixed, affecting the material formation results. The heat insulation screen in a vacuum sintering furnace is generally composed of graphite plates and carbon felt, which are relatively easy to disassemble. Therefore, a simulation method is needed to determine the thermal insulation performance of the insulation layer in a vacuum sintering furnace, specifically to find the parameter range of the heat insulation screen structure, mainly the thickness of the carbon felt. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application proposes a temperature damage detection method and temperature measuring device based on an optimized vacuum sintering furnace.

[0007] Firstly, this application proposes a method for detecting temperature damage in an optimized vacuum sintering furnace, including:

[0008] Based on the parameters of the vacuum sintering furnace body, a model of thermal radiation and heat conduction during the heating process of the vacuum sintering furnace is established. Based on the thermal radiation and heat conduction model, the temperature rise curve and workpiece temperature are obtained.

[0009] The structure of the vacuum sintering furnace was optimized by adopting different insulation structures. The temperature of the vacuum sintering furnace after structural optimization was predicted by using the parameter iteration method, and a one-dimensional performance simulation model of the carbon felt insulation layer was derived.

[0010] Based on the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve and the workpiece temperature, the range of the thickness of the carbon felt insulation layer at different sintering temperatures is calculated using the principle of reverse simulation. Then, the optimal thickness of the carbon felt insulation layer is obtained from the range of the thickness of the carbon felt insulation layer at different sintering temperatures using forward simulation.

[0011] The optimal thickness of the carbon felt insulation layer is used as the length of the temperature measuring device to construct a temperature measuring device for the vacuum sintering furnace. The temperature of the vacuum sintering furnace is measured using multiple temperature measuring devices, and the temperature damage detection results are obtained based on the measurement results.

[0012] The method of predicting the temperature of the vacuum sintering furnace after structural optimization using parameter iteration, and deriving a one-dimensional performance simulation model of the carbon felt insulation layer, includes:

[0013] Step S2.1: Use Fluent software to calculate the first total heat flux of the carbon felt insulation layer in the effective heating zone of the vacuum sintering furnace after structural optimization, as well as the workpiece temperature in the first furnace.

[0014] Step S2.2: Establish a finite element model of the vacuum sintering furnace after structural optimization, and use the first total heat flux and the workpiece temperature in the first furnace as boundary conditions to calculate the transient temperature of each layer of graphite plate and carbon felt insulation layer.

[0015] Step S2.3: Average the transient temperature of each layer of the graphite plate and carbon felt insulation layer to obtain the temperature of each layer of the carbon felt insulation layer;

[0016] Step S2.4: Using the temperatures of the first and second layers of the carbon felt insulation layer as references, calculate the heat flow between the two layers;

[0017] Step S2.5: Using the heat flux of the two layers as initial conditions, calculate the second total heat flux of the carbon felt insulation layer in the effective heating zone and the workpiece temperature in the second furnace;

[0018] Step S2.6: If the difference between the first total heat flux and the second total heat flux is less than the preset total heat flux threshold, or if the difference between the workpiece temperature in the first furnace and the workpiece temperature in the second furnace is less than the preset temperature threshold, stop the iteration, output the corresponding effective heating zone carbon felt insulation layer, and go to step S2.7; otherwise, take the second total heat flux as the first total heat flux and the workpiece temperature in the second furnace as the workpiece temperature in the first furnace, and go to step S2.2 to continue the iteration.

[0019] Step S2.7: Analyze the effective heating zone carbon felt insulation layer corresponding to the iteration stop, and derive a one-dimensional performance simulation model of the carbon felt insulation layer.

[0020] The derived one-dimensional performance simulation model of the carbon felt insulation layer is calculated as follows:

[0021]

[0022]

[0023]

[0024] Where λ is the thermal conductivity of the carbon felt, T r T1 is the temperature of the heating element, T2 is the temperature of the inner wall of the carbon felt, T3 is the temperature of the inner wall of the furnace shell, and ε is the temperature of the heating element. r ε1 represents the emissivity of the heating element, ε2 represents the emissivity of the inner wall of the carbon felt, ε3 represents the emissivity of the inner wall of the furnace shell, and A represents the emissivity of the inner wall of the furnace shell. r Let A1 be the area of ​​the heating element, A2 be the area of ​​the inner wall of the carbon felt, A3 be the area of ​​the inner wall of the furnace shell, L be the height of the carbon felt, D1 be the diameter of the inner wall of the carbon felt, and D2 be the diameter of the outer wall. The heating element radiates heat to the inner wall of the carbon felt. For heat conduction within the carbon felt, σ0 represents the radiation from the outer wall of the carbon felt and the furnace shell, and σ0 is the radiation coefficient of an absolute blackbody.

[0025] Based on the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve, and the workpiece temperature, the range of thickness values ​​for the carbon felt insulation layer at different sintering temperatures is calculated using the reverse simulation principle. Then, using forward simulation, the optimal thickness of the carbon felt insulation layer is obtained within the range of thickness values ​​at different sintering temperatures, including:

[0026] For the finite element model of the vacuum sintering furnace after structural optimization, the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve and the workpiece temperature are input, and the range of values ​​for the thickness of the carbon felt insulation layer at different sintering temperatures is calculated using the principle of inverse simulation.

[0027] Based on the desired carbon felt insulation layer thickness, a forward simulation was performed on the finite element model of the optimized vacuum sintering furnace. Within the range of carbon felt insulation layer thickness values, the thickness that makes the furnace temperature most uniform was selected as the optimal carbon felt insulation layer thickness.

[0028] The temperature of the vacuum sintering furnace is measured using multiple temperature measuring devices. Based on the measurement results, temperature damage detection results are obtained, including:

[0029] Multiple temperature measuring devices were used to measure the temperature at different locations in the vacuum sintering furnace, and multiple measurement results were obtained.

[0030] Choose one target measurement result from multiple measurement results;

[0031] The difference between the target measurement result and all other measurement results is calculated, and multiple differences are obtained. When there are two differences that are greater than the preset difference threshold, the location of the vacuum sintering furnace corresponding to the target measurement result is the damage location.

[0032] Secondly, this application proposes a temperature measuring device based on an optimized vacuum sintering furnace, comprising: a quartz tube, a tungsten connecting rod, a tungsten push rod, an inlet stage, a thermocouple stage, and an outlet stage;

[0033] The length of the quartz tube is the optimal thickness of the carbon felt insulation layer, and a thermocouple is installed on the thermocouple stage. The thermocouple is used to measure the temperature inside the carbon felt insulation layer.

[0034] The inlet stage is fixed to the inlet end of the quartz tube, the outlet stage is fixed to the outlet end of the quartz tube, the thermocouple stage is inside the quartz tube and moves between the inlet stage and the outlet stage, there are two tungsten connecting rods, the tungsten push rod is between the two tungsten connecting rods, the tungsten connecting rods and the tungsten push rod pass through the inside of the quartz tube and pass through the inlet stage, the thermocouple stage and the outlet stage.

[0035] Both the inlet and outlet stages are equipped with pin holes, which are connected by pins to fix the inlet and outlet stages to the quartz tube respectively.

[0036] A ceramic tube is installed inside the tungsten connecting rod, and an electric wire is inside the ceramic tube, which is connected to a thermocouple.

[0037] A thermocouple support and a thermal resistance humidity sensor are installed on the thermocouple stage.

[0038] The thermocouple bracket is used to fix and install the thermocouple and serves as a limiting device for the thermocouple.

[0039] The thermal resistance humidity sensor is used to determine whether the temperature measurement value of the thermocouple is affected by humidity and thus produces an error.

[0040] The tungsten push rod is fixedly installed on the thermocouple stage and connected to an external cylinder to enable the thermocouple to move inside the quartz tube.

[0041] Beneficial effects:

[0042] This application proposes a temperature damage detection method and temperature measuring device based on an optimized vacuum sintering furnace. For the optimized vacuum sintering furnace, a parameter iteration method is used to predict the temperature of the optimized furnace, and a one-dimensional performance simulation model of the carbon felt insulation layer is derived. This leads to the optimal thickness of the carbon felt insulation layer, solving the problem of not being able to directly measure the temperature within the effective heating zone after structural optimization due to excessively high temperatures. It also avoids the problem of requiring numerous experiments for direct measurement based on experimental data. This method reduces experimental costs, extends the lifespan of the vacuum sintering furnace, and improves the yield. Furthermore, the optimal thickness of the carbon felt insulation layer is used as the length of the temperature measuring device, which is designed and used to measure temperature damage and obtain the detection results. This temperature measuring device improves the accuracy of temperature measurement and solves the problem that thermocouples cannot be directly placed inside the furnace chamber due to their inability to withstand high temperatures. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 A flowchart of a temperature damage detection method based on an optimized vacuum sintering furnace according to an embodiment of this application;

[0045] Figure 2 A schematic diagram of the temperature rise process curve of an embodiment of this application;

[0046] Figure 3 Flowchart of the parameter iteration method in this application;

[0047] Figure 4 A schematic diagram of the parameter iteration method in an embodiment of this application;

[0048] Figure 5 The flowchart of obtaining the optimal thickness of the carbon felt insulation layer in the embodiments of this application is shown below;

[0049] Figure 6 A schematic diagram illustrating the optimal thickness of the carbon felt insulation layer in this embodiment of the application;

[0050] Figure 7 This application's embodiment shows a schematic diagram of the selection of temperature measurement locations for the insulation layer;

[0051] Figure 8 A schematic diagram of the external cylinder-driven temperature measuring device in an embodiment of this application;

[0052] Figure 9 A schematic diagram of the temperature measuring device inserted into the carbon felt insulation layer according to an embodiment of this application;

[0053] Figure 10 A schematic diagram of the external structure of the temperature measuring device according to an embodiment of this application;

[0054] Figure 11 A schematic diagram of the internal structure of the temperature measuring device according to an embodiment of this application;

[0055] Figure 12 A schematic diagram of the bottom of the thermocouple stage in this embodiment of the application;

[0056] Figure 13 A side view of the thermocouple stage according to an embodiment of this application;

[0057] Figure 14 Top view of the thermocouple stage in this embodiment;

[0058] Figure 15 A schematic diagram of the thermocouple structure in an embodiment of this application;

[0059] Figure 16 This application implements a one-dimensional performance simulation model with subscript diagram;

[0060] Among them, 1-quartz tube, 2-tungsten connecting rod, 3-tungsten push rod, 4-inlet stage, 5-thermocouple stage, 6-outlet stage, 7-wire, 8-thermocouple, 9-thermal resistance humidity sensor, 10-thermocouple bracket, 11-thermocouple stage through hole, 12-internal wiring hole, 13-armored protective tube, 14-temperature measuring point, 15-R-type iron-nickel alloy, 16-temperature processing system, 17-cylinder. Detailed Implementation

[0061] The specific implementation methods of this application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0062] This application proposes a temperature damage detection method and temperature measuring device based on an optimized vacuum sintering furnace. To further improve the temperature uniformity within the vacuum sintering furnace, structural optimization of the furnace is necessary. Due to the excessively high temperature, it is impossible to directly measure the temperature within the effective heating zone after structural optimization. Direct measurement using experimental data requires numerous experiments, significantly increasing costs. Furthermore, without specific furnace temperature conditions, the furnace structure's lifespan will be affected by high temperatures, greatly reducing yield. Additionally, different workpieces require different temperatures for production. If the original furnace structure is used, its insulation layer parameters are generally fixed, and the insulation performance of the original scheme may not meet requirements. As a result, the final material output exhibits inconsistent properties due to incomplete temperature dissipation and reaction. This application provides a more accurate insulation layer thickness range based on a one-dimensional performance simulation model of the carbon felt insulation layer.

[0063] Finally, in existing technologies, most temperature measurements are taken using infrared thermometry. However, because infrared thermometry does not come into contact with solids, the accuracy of temperature measurement is very poor. When sintering in a vacuum sintering furnace, the temperature can reach over 1500℃. Thermocouples cannot be directly placed inside the furnace chamber because they cannot withstand the high temperature and cannot detect abnormal conditions inside the furnace. Furthermore, since some air is carried in when the workpiece is loaded, water vapor will evaporate inside the furnace when the air is heated, making it impossible to monitor and predict faults inside the furnace and during sintering in real time. Therefore, this application designs a device that can directly measure the temperature of the insulation layer, predict the temperature inside the furnace, and predict factors that could cause damage inside the furnace.

[0064] Example 1:

[0065] This application proposes a method for detecting temperature damage in an optimized vacuum sintering furnace, such as... Figure 1 As shown, it includes:

[0066] Step S1: Establish a model of thermal radiation and heat conduction during the heating process of the vacuum sintering furnace based on the parameters of the vacuum sintering furnace body. Based on the thermal radiation and heat conduction model, obtain the temperature rise curve and workpiece temperature.

[0067] In this embodiment, the thermal radiation and heat conduction models are calculated as follows:

[0068] The pressure inside the vacuum sintering furnace is 101325 Pa before coke discharge is completed, and the vacuum level is 50 Pa after coke discharge. Neglecting convective heat transfer, the energy equation is:

[0069]

[0070] Where t is time, in seconds; ρ is density, in kg / m³. 3 h is specific enthalpy, with units of kJ / kg, h=∫C p dT, where C p Specific heat capacity at constant pressure (J / (kg·K)); λ is the Hamiltonian operator; u is the velocity vector, in m / s; λ is the thermal conductivity, in W / (m·K); T is the temperature, in K; S h Internal heat source, unit is W / m 3 The thermophysical properties of the material are shown in Table 1.

[0071] Using the discrete ordinate DO radiation model, the radiation heat transfer model is as follows:

[0072]

[0073] Where I represents radiation intensity, with units of W / m². 2 r is the normal vector of the radiation azimuth angle; s is the vector of the radiation path length; s′ is the scattering direction; α is the material absorption coefficient; σs σ is the heat dissipation coefficient; n is the refractive index; σ is the blackbody radiation constant; Ω′ is the radiation solid angle.

[0074] Table 1. Thermophysical properties of the materials

[0075]

[0076] The temperature rise curve and power control were simulated using UDF, and the energy equation and discrete DO radiation model were enabled. Temperature monitoring points were set on the workpiece to obtain the temperature rise curve of the vacuum sintering furnace during the entire heating process.

[0077] The accuracy of the simulation process was verified by comparing the temperature sensor temperature and the heating curve with the actual heating process.

[0078] The process of optimizing the original furnace type by obtaining the workpiece temperature rise curve and the average temperature difference of all workpieces is as follows: Under the production process requirement of meeting the temperature difference between the surface and core of the same workpiece <5℃, select the set of curves that best matches the actual production curves as the reference process curves, such as... Figure 2 As shown.

[0079] Step S2: Optimize the structure of the vacuum sintering furnace using different insulation structures. Predict the temperature of the vacuum sintering furnace after structural optimization using a parameter iteration method, and derive a one-dimensional performance simulation model of the carbon felt insulation layer, such as... Figure 3 , Figure 4 As shown, it includes:

[0080] Step S2.1: Use Fluent software to calculate the first total heat flux Q1 of the carbon felt insulation layer in the effective heating zone of the vacuum sintering furnace after structural optimization, and the first workpiece temperature T in the furnace. SIC1 ;

[0081] Step S2.2: Establish a finite element model of the vacuum sintering furnace after structural optimization, and combine the first total heat flux Q1 and the first workpiece temperature T inside the furnace. SIC1 As boundary conditions, calculate the transient temperature of each layer (10mm per layer) of graphite plate and carbon felt insulation layer;

[0082] Step S2.3: Average the transient temperature of each layer of the graphite plate and carbon felt insulation layer to obtain the temperature T = {T1, T2, ..., Tx} of each layer of the carbon felt insulation layer;

[0083] Step S2.4: Using the temperatures T6 of the first layer and T7 of the second layer of the carbon felt insulation layer as references, calculate the heat flux Q between the two layers. cross ;

[0084] Step S2.5: Using the heat flux Q of the two layers crossAs initial conditions, calculate the second total heat flux Q2 of the carbon felt insulation layer in the effective heating zone and the second workpiece temperature T in the furnace. SIC2 ;

[0085] Step S2.6: If the difference between the first total heat flux and the second total heat flux is less than a preset total heat flux threshold (i.e., Q...) cross and Q come If the temperature difference between the workpiece in the first furnace and the workpiece in the second furnace is less than the preset temperature threshold, the iteration stops, the corresponding effective heating zone carbon felt insulation layer is output, and the process proceeds to step S2.7. Otherwise, the second total heat flux is used as the first total heat flux, and the workpiece temperature in the second furnace is used as the workpiece temperature in the first furnace. The process proceeds to step S2.2 to continue the iteration.

[0086] Step S2.7: Analyze the effective heating zone carbon felt insulation layer corresponding to the iteration stop, and derive a one-dimensional performance simulation model of the carbon felt insulation layer.

[0087] A one-dimensional performance simulation calculation model of the vacuum sintering furnace after structural modification is established and calibrated. A three-dimensional FLUENT simulation calculation model of the vacuum sintering furnace, including turbulence model, viscosity model and radiation model, corresponding to the model established in step S1, is established and calibrated. The water-cooled wall temperature, room temperature and heating body power set in the established one-dimensional model are used as the initial temperature boundary conditions for the three-dimensional simulation calculation.

[0088] Acquire initial workpiece data, data on holding time points and chemical reaction occurrences within the sintering furnace, a three-dimensional model of the equipment, process data for the sintering process, and ideal state data for the product output furnace. Compile temperature curves of the workpiece during holding within the sintering furnace, collect workpiece data at multiple holding points, and obtain parameter data during normal equipment operation, including input operation commands and data on changes at various points within the equipment during operation. Establish a finite element model of the optimized vacuum sintering furnace and simulate the insulation layer of different workpiece structures, changing the physical property parameters of the mesh corresponding to the insulation area to the parameters of the new insulation layer.

[0089] A forward simulation operation model and a reverse simulation operation model are established. The reverse simulation operation model is formed by combining the three-dimensional model of the equipment with the equipment's operation rule data. The operation rule data is obtained by extracting features from normal material operation data in the furnace and obtaining normal results. The feature extraction process is carried out in reverse. The output results are substituted into the one-dimensional performance simulation calculation model of carbon felt obtained in step S2.7 to obtain the reverse operation rules. The feature extraction process is carried out in the forward direction, from the input conditions to the output results to obtain the forward operation rules. The dynamic command data control simulation operation model is combined to simulate the sintering of the workpiece in the sintering furnace and obtain simulation data. The simulation data is compared with the optimal data range, and the heat shield parameters of the vacuum sintering furnace operation process are adjusted based on the simulation data analysis results.

[0090] The workpiece data includes: workpiece shape, physical properties, normal temperature, humidity, etc., while the equipment data includes: furnace vacuum degree, furnace temperature, humidity. This embodiment adopts a reverse reaction, that is, first obtaining the ideal reaction temperature, final state temperature, and humidity of the product, then using a one-dimensional mathematical model of the temperature between each layer of carbon felt insulation to derive the appropriate range of carbon felt layers, and finally using forward simulation to determine the impact of specific equipment parameters on the output results.

[0091] Step S3: Based on the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve, and the workpiece temperature, the range of thickness values ​​for the carbon felt insulation layer at different sintering temperatures is calculated using the reverse simulation principle. Then, using forward simulation, the optimal thickness of the carbon felt insulation layer is obtained within the range of thickness values ​​at different sintering temperatures. Figure 5 , Figure 6 ,include:

[0092] Step S3.1: For the finite element model of the vacuum sintering furnace after structural optimization, input the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve and the workpiece temperature, and use the reverse simulation principle to calculate the range of values ​​for the thickness of the carbon felt insulation layer at different sintering temperatures.

[0093] Step S3.2: Perform a forward simulation on the finite element model of the vacuum sintering furnace after structural optimization based on the desired carbon felt insulation layer thickness. Select the thickness that makes the furnace temperature most uniform within the range of carbon felt insulation layer thickness as the optimal carbon felt insulation layer thickness.

[0094] Step S4: Using the optimal thickness of the carbon felt insulation layer as the length of the temperature measuring device, construct the temperature measuring device for the vacuum sintering furnace. Use multiple temperature measuring devices to measure the temperature of the vacuum sintering furnace, and obtain the temperature damage detection results based on the measurement results.

[0095] The derived one-dimensional performance simulation model of the carbon felt insulation layer is calculated as follows:

[0096]

[0097]

[0098]

[0099] Where λ is the thermal conductivity of the carbon felt, in W / (m·K); T r T1, T2, and T3 are the temperatures of the heating element, the inner and outer walls of the carbon felt, and the inner wall of the furnace shell, respectively, in K; ε r ε1, ε2, and ε3 represent the emissivity of the heating element, the inner and outer walls of the carbon felt, and the inner wall of the furnace shell, respectively; A1, A2, A3, and A4 represent the areas of the heating element, the inner and outer walls of the carbon felt, and the inner wall of the furnace shell, respectively, in m². 2 L, D1, and D2 are the height of the carbon felt, the inner diameter of the carbon felt, and the outer diameter of the carbon felt, respectively, in meters. These represent the radiation radiated by the heating element to the inner wall of the carbon felt, the heat conduction within the carbon felt, and the radiation between the outer wall of the carbon felt and the furnace shell, respectively; σ0 is the emissivity of a blackbody, in W / (m²). 2 ·K 4 ),like Figure 16 As shown in the figure, r, 1, 2, and 3 represent the subscripts of the letters in the above calculation formula, where r represents the heating element, 1 represents the inner wall of the carbon felt, 2 represents the outer wall of the carbon felt, and 3 represents the inner wall of the furnace shell.

[0100] Based on the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve, and the workpiece temperature, the range of thickness values ​​for the carbon felt insulation layer at different sintering temperatures is calculated using the inverse simulation principle. Then, using forward simulation, the optimal thickness of the carbon felt insulation layer is obtained within the range of thickness values ​​at different sintering temperatures.

[0101] The temperature of the vacuum sintering furnace is measured using multiple temperature measuring devices. Based on the measurement results, temperature damage detection results are obtained, including:

[0102] Multiple temperature measuring devices were used to measure the temperature at different locations in the vacuum sintering furnace, and multiple measurement results were obtained.

[0103] Choose one target measurement result from multiple measurement results;

[0104] The difference between the target measurement result and all other measurement results is calculated, and multiple differences are obtained. When there are two differences that are greater than the preset difference threshold, the location of the vacuum sintering furnace corresponding to the target measurement result is the damage location.

[0105] Example 2:

[0106] This embodiment proposes a temperature measuring device based on an optimized vacuum sintering furnace, including: a quartz tube 1, a tungsten connecting rod 2, a tungsten push rod 3, an inlet stage 4, a thermocouple stage 5, and an outlet stage 6.

[0107] Among them, the length of the quartz tube 1 is the optimal thickness of the carbon felt insulation layer, and the thermocouple 8 is installed on the thermocouple stage 5. The thermocouple 8 is used to measure the temperature inside the carbon felt insulation layer.

[0108] The inlet stage 4 is fixed to the inlet end of the quartz tube 1, the outlet stage 6 is fixed to the outlet end of the quartz tube 1, the thermocouple stage 5 is inside the quartz tube 1 and moves between the inlet stage 4 and the outlet stage 6, there are two tungsten connecting rods 2, the tungsten push rod 3 is between the two tungsten connecting rods 2, the tungsten connecting rods 2 and the tungsten push rod 3 pass through the interior of the quartz tube 1, and pass through the inlet stage 4, the thermocouple stage 5 and the outlet stage 6.

[0109] Both the inlet platform 4 and the outlet platform 6 are provided with pin holes, which are connected by pins to fix the inlet platform 4 and the outlet platform 6 to the quartz tube 1 respectively.

[0110] A ceramic tube is installed inside the tungsten connecting rod 2, and an electric wire 7 is installed inside the ceramic tube. The electric wire 7 is connected to the thermocouple 8.

[0111] A thermocouple bracket 10 and a thermal resistance humidity sensor 9 are installed on the thermocouple stage 5.

[0112] The thermocouple bracket 10 is used to fix the thermocouple 8 and serves as a limiting device for the thermocouple 8.

[0113] The thermal resistance humidity sensor 9 is used to determine whether the temperature measurement value of the thermocouple 8 is affected by humidity and thus produces an error.

[0114] The tungsten push rod 3 is fixedly installed on the thermocouple stage 5 and connected to the external cylinder 17 to move the thermocouple 8 inside the quartz tube 1. The thermocouple stage 5 has two thermocouple stage through holes 11 and one internal wiring hole 12, through which the tungsten connecting rod 2 passes and the wire 7 passes.

[0115] In this embodiment, 11 longitudinal temperature measurement points are first selected in the carbon felt insulation layer area, such as... Figure 7 As shown, an external cylinder 17 drives a tungsten push rod 3 to move a quartz tube 1, as... Figure 8 , Figure 9 As shown, a temperature measuring device based on an optimized vacuum sintering furnace is inserted into the longitudinal temperature measuring hole, such as... Figure 10 , Figure 11As shown, the device includes: a quartz tube 1, a tungsten connecting rod 2, a tungsten push rod 3, an armored thermocouple 8, a high-temperature resistant ceramic tube, and a thermal resistance humidity sensor 9. The left inlet end of the quartz tube 1 is a conventional cylindrical shape, while the right outlet end is pointed for better insertion into the carbon felt layer. Three stage bases are provided at the inlet, middle, and outlet positions of the quartz tube 1. Each stage base has pin holes, which are connected by pins to fix the stage bases to the quartz tube 1, preventing displacement during insertion. The armored thermocouple 8 is mounted on the stage, facing the heating direction inside the furnace. To ensure safe measurement and protection of the thermocouple wires and humidity sensor wires in high-temperature environments, both the thermocouple wires and humidity sensor wires are housed within ceramic tubes inside the tungsten connecting rod 2, with two wires in each ceramic tube. This embodiment proposes a temperature measuring device based on an optimized vacuum sintering furnace, the technical solution of which is detailed below:

[0116] First, the thermocouple wires and humidity sensor wires are processed. Use wire strippers or an electrician's knife to precisely strip the insulation layer from the ends of the wires. The stripping length needs to be determined according to the size and shape of the high-temperature resistant ceramic tube socket to be inserted later, so as to ensure that the conductor can be fully and smoothly inserted into the socket and form a smooth conical transition part, which makes it easy for the wire to pass smoothly into the ceramic tube and be protected.

[0117] Next, the core structure of the device includes a quartz tube 1, a tungsten connecting rod 2, a tungsten push rod 3, and a thermocouple stage 5 (graphite stage), such as... Figure 12 , Figure 13 , Figure 14 As shown, the graphite stage has two transverse through holes on its side, each housing a tungsten connecting rod 2. The stage and these two tungsten connecting rods 2 are movably connected. One end of each connecting rod 2 is fixed in the transverse through hole of the inlet stage 4, and the other end is fixed in the transverse through hole of the outlet stage 6, ensuring structural stability and continuous wiring transmission. Importantly, the left end of each tungsten connecting rod 2 is equipped with external circuit terminals. These terminals are led out through high-temperature resistant ceramic tubes embedded inside the tungsten rods, protecting the wiring and ensuring accurate temperature measurements.

[0118] In addition, the inlet stage 4 and outlet stage 6 are fixed to the inlet and outlet of the quartz tube 1, respectively. They are connected to the side of the movable thermocouple stage 5 with transverse through holes for mounting the tungsten connecting rod 2. The movable thermocouple stage 5 is the main body of the temperature measuring device. It has a thermocouple 8 for measuring the temperature inside the insulation layer, a thermal resistance humidity sensor 9 to determine if the current temperature is affected by humidity and thus produces an error, and a tungsten push rod 3 connected to an external cylinder 17 to move the thermocouple inside the quartz tube to determine the extent of damage to the insulation layer. The thermocouple bracket 10 acts as a limiting device to fix the thermocouple 8. The thermocouple 8 is encased in an armored protective tube 13, and the temperature measuring point 14 is inside the armored protective tube 13. The material of the temperature measuring point 14 is R-type iron-nickel alloy 15. The temperature data measured by the thermocouple 8 is transmitted to the temperature processing system 16 for processing. Figure 15 As shown.

[0119] In summary, this embodiment, through its carefully designed structure, not only achieves safe transmission and measurement of thermocouple wires and humidity sensor wires in high-temperature environments, but also ensures the horizontal mobility and measurement accuracy of the temperature measuring device.

[0120] The various embodiments in this application are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0121] The scope of protection of this application is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from the scope and spirit of this disclosure. If such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, then the intent of this disclosure also includes such modifications and variations.

Claims

1. A method for detecting temperature damage in an optimized vacuum sintering furnace, characterized in that, include: Based on the parameters of the vacuum sintering furnace body, a model of thermal radiation and heat conduction during the heating process of the vacuum sintering furnace is established. Based on the thermal radiation and heat conduction model, the temperature rise curve and workpiece temperature are obtained. The structure of the vacuum sintering furnace was optimized by adopting different insulation structures. The temperature of the vacuum sintering furnace after structural optimization was predicted by using the parameter iteration method, and a one-dimensional performance simulation model of the carbon felt insulation layer was derived. Based on the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve and the workpiece temperature, the range of the thickness of the carbon felt insulation layer at different sintering temperatures is calculated using the principle of reverse simulation. Then, the optimal thickness of the carbon felt insulation layer is obtained from the range of the thickness of the carbon felt insulation layer at different sintering temperatures using forward simulation. The optimal thickness of the carbon felt insulation layer is used as the length of the temperature measuring device to construct a temperature measuring device for the vacuum sintering furnace. The temperature of the vacuum sintering furnace is measured using multiple temperature measuring devices, and the temperature damage detection results are obtained based on the measurement results.

2. The temperature damage detection method based on the optimized vacuum sintering furnace according to claim 1, characterized in that, The method of predicting the temperature of the vacuum sintering furnace after structural optimization using parameter iteration, and deriving a one-dimensional performance simulation model of the carbon felt insulation layer, includes: Step S2.1: Use Fluent software to calculate the first total heat flux of the carbon felt insulation layer in the effective heating zone of the vacuum sintering furnace after structural optimization, as well as the workpiece temperature in the first furnace. Step S2.2: Establish a finite element model of the vacuum sintering furnace after structural optimization, and use the first total heat flux and the workpiece temperature in the first furnace as boundary conditions to calculate the transient temperature of each layer of graphite plate and carbon felt insulation layer. Step S2.3: Average the transient temperature of each layer of the graphite plate and carbon felt insulation layer to obtain the temperature of each layer of the carbon felt insulation layer; Step S2.4: Using the temperatures of the first and second layers of the carbon felt insulation layer as references, calculate the heat flow between the two layers; Step S2.5: Using the heat flux of the two layers as initial conditions, calculate the second total heat flux of the carbon felt insulation layer in the effective heating zone and the workpiece temperature in the second furnace; Step S2.6: If the difference between the first total heat flux and the second total heat flux is less than the preset total heat flux threshold, or if the difference between the workpiece temperature in the first furnace and the workpiece temperature in the second furnace is less than the preset temperature threshold, stop the iteration, output the corresponding effective heating zone carbon felt insulation layer, and go to step S2.7; otherwise, take the second total heat flux as the first total heat flux and the workpiece temperature in the second furnace as the workpiece temperature in the first furnace, and go to step S2.2 to continue the iteration. Step S2.7: Analyze the effective heating zone carbon felt insulation layer corresponding to the iteration stop, and derive a one-dimensional performance simulation model of the carbon felt insulation layer.

3. The temperature damage detection method based on the optimized vacuum sintering furnace according to claim 2, characterized in that, The derived one-dimensional performance simulation model of the carbon felt insulation layer is calculated as follows: ； ； ； Where λ is the thermal conductivity of the carbon felt, T r T1 represents the temperature of the heating element, T2 represents the temperature of the inner wall of the carbon felt, T3 represents the temperature of the outer wall of the carbon felt, and T4 represents the temperature of the inner wall of the furnace shell. For the emissivity of the heating element, The blackness of the inner wall of the carbon felt. The blackness of the outer wall of the carbon felt. A represents the emissivity of the inner wall of the furnace shell. r Let A1 be the area of ​​the heating element, A2 be the area of ​​the inner wall of the carbon felt, A3 be the area of ​​the inner wall of the furnace shell, L be the height of the carbon felt, D1 be the diameter of the inner wall of the carbon felt, and D2 be the diameter of the outer wall. The heating element radiates heat to the inner wall of the carbon felt. For heat conduction within the carbon felt, The radiation from the outer wall of the carbon felt and the furnace shell, is the radiation coefficient of a blackbody.

4. The temperature damage detection method based on the optimized vacuum sintering furnace according to claim 1, characterized in that, Based on the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve, and the workpiece temperature, the range of thickness values ​​for the carbon felt insulation layer at different sintering temperatures is calculated using the reverse simulation principle. Then, using forward simulation, the optimal thickness of the carbon felt insulation layer is obtained within the range of thickness values ​​at different sintering temperatures, including: For the finite element model of the vacuum sintering furnace after structural optimization, the one-dimensional performance simulation model of the carbon felt insulation layer, the temperature rise curve and the workpiece temperature are input, and the range of values ​​for the thickness of the carbon felt insulation layer at different sintering temperatures is calculated using the principle of inverse simulation. Based on the desired carbon felt insulation layer thickness, a forward simulation was performed on the finite element model of the optimized vacuum sintering furnace. Within the range of carbon felt insulation layer thickness values, the thickness that makes the furnace temperature most uniform was selected as the optimal carbon felt insulation layer thickness.

5. The temperature damage detection method based on the optimized vacuum sintering furnace according to claim 1, characterized in that, The temperature of the vacuum sintering furnace is measured using multiple temperature measuring devices. Based on the measurement results, temperature damage detection results are obtained, including: Multiple temperature measuring devices were used to measure the temperature at different locations in the vacuum sintering furnace, and multiple measurement results were obtained. Choose one target measurement result from multiple measurement results; The difference between the target measurement result and all other measurement results is calculated, and multiple differences are obtained. When there are two differences that are greater than the preset difference threshold, the location of the vacuum sintering furnace corresponding to the target measurement result is the damage location.

Images