A multi-parameter controllable thermal conductivity testing system and method

Abstract

The present invention relates to a multi-parameter controllable thermal conductivity testing system and method, belonging to the technical field of thermal conductivity testing, and solving the problems of large error in the thermal conductivity measured by the existing testing system and inability to control the deformation amount of the sample. The testing system includes a heating system, a loading system, a measuring system and a vacuum system; the heating system includes an upper heating plate and a lower heating plate, the loading system includes a loading head and a loading column, the measuring system includes a pressure sensor and a displacement sensing device, and the vacuum system includes a vacuum chamber; the upper heating plate and the lower heating plate are arranged in the vacuum chamber, the upper heating plate is located above the lower heating plate, the loading head is located above the vacuum chamber, the loading column penetrates the upper wall of the vacuum chamber to connect the loading head with the upper heating plate, the pressure sensor is located on the loading head, the displacement sensing device includes a push rod and a displacement sensor, the displacement sensor is located above the vacuum chamber, and the push rod penetrates the upper wall of the vacuum chamber to connect the displacement sensor with the upper heating plate. It realizes flexible control of the deformation amount of the sample and accurate measurement of the thermal conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal conductivity testing, and in particular, to a multi-parameter controllable thermal conductivity testing system and method. Background Art

[0002] Flexible thermal insulation materials have good high-temperature thermal insulation performance and low density, and have broad application prospects. Flexible thermal insulation materials have a wide range of use temperatures and large temperature gradients in the use environment.

[0003] Existing testing methods for the thermal conductivity of thermal insulation materials (such as the hot flow meter method in GB / T 10295, and its typical equipment is the FOX series thermal conductivity meters of TA Company; the guarded hot plate method in GB / T 10294, and its typical equipment is the GHP456 thermal conductivity meters of Netzsch Company; the water flow flat plate method in YB / T 4130, and the typical equipment is the PBD series thermal conductivity meters of Luoyang Institute of Refractories, etc.) have different test accuracies and measurement temperature ranges due to different equipment and principles. In the prior art, in order to ensure full contact between the sample and the heating body, usually a certain pressure is applied to the sample by the heating plate. Different methods and even different equipment apply different pressures to the sample, which will cause different deformation amounts of the sample, resulting in large thickness changes, thereby generating large errors in the measurement results of the thermal conductivity. Summary of the Invention

[0004] In view of the above analysis, embodiments of the present invention aim to provide a multi-parameter controllable thermal conductivity testing system and method to solve the problems of large errors in the thermal conductivity measured by the existing testing system and inability to control the deformation amount of the sample.

[0005] On the one hand, embodiments of the present invention provide a multi-parameter controllable thermal conductivity testing system, including a heating system, a loading system, a measurement system, and a vacuum system;

[0006] The heating system includes an upper heating plate and a lower heating plate, the loading system includes a loading head and a loading column connected in sequence from top to bottom, the measurement system includes a pressure sensor and a displacement sensing device, and the vacuum system includes a vacuum chamber;

[0007] The upper heating plate and the lower heating plate are arranged in the vacuum chamber, the upper heating plate is located above the lower heating plate, the loading head is located above the vacuum chamber, one end of the loading column passes through the upper wall of the vacuum chamber and is connected to the upper heating plate, the pressure sensor is located on the loading head, the displacement sensing device includes a displacement sensor and a push rod connected in sequence from top to bottom, the displacement sensor is located above the vacuum chamber, and one end of the push rod passes through the upper wall of the vacuum chamber and is connected to the upper heating plate.

[0008] Preferably, the loading system further includes a spring. The loading column includes an upper loading column and a lower loading column. The upper end of the upper loading column is connected to the loading head. The lower end of the lower loading column passes through the upper wall of the vacuum chamber and is connected to the upper heating plate. A spring is sleeved between the lower end of the upper loading column and the upper end of the lower loading column. The upper end of the spring is connected to the outer periphery of the lower end of the upper loading column, and the lower end of the spring is connected to the outer periphery of the upper end of the lower loading column.

[0009] Preferably, the loading system further includes a loading device lifting mechanism, which is arranged above the loading head and connected to the loading head.

[0010] Preferably, the measurement system further includes a thermocouple. The thermocouple penetrates the upper heating plate and contacts the upper surface of the sample, and penetrates the lower heating plate and contacts the lower surface of the sample.

[0011] Preferably, the measurement system further includes a heat flux measurement device, which is arranged on the upper surface of the lower heating plate.

[0012] Preferably, the measurement system further includes a vacuum gauge, which is located outside the vacuum chamber and communicates with the inside of the vacuum chamber.

[0013] Preferably, a heat insulation layer is arranged in the vacuum chamber. The heat insulation layer encloses a heat insulation cavity, and the upper heating plate and the lower heating plate are located in the heat insulation cavity.

[0014] Preferably, the vacuum system further includes a mechanical pump and / or a molecular pump, which communicate with the inside of the vacuum chamber.

[0015] Preferably, the multi-parameter controllable thermal conductivity test system further includes a lifting system. The lifting system includes a motor, a cross bar, two right-angle adapters, two lead screws and two vacuum chamber lifting mechanisms. The vacuum chamber lifting mechanisms are respectively arranged on both sides of the vacuum chamber and connected to the vacuum chamber. The two ends of the cross bar are respectively connected to the lead screws through the right-angle adapters, and the lead screws are respectively connected to the vacuum chamber lifting mechanisms.

[0016] On the other hand, the present invention also provides a multi-parameter controllable thermal conductivity test method. Using the multi-parameter controllable thermal conductivity test system of the present invention, the multi-parameter controllable thermal conductivity test method includes:

[0017] (a) Adjust the state of the sample and record the initial thickness; and set the value of the displacement sensor when the upper heating plate and the lower heating plate are in contact to zero.

[0018] (b) Lift the vacuum chamber through the vacuum chamber lifting mechanism, and at the same time lift the upper heating plate through the loading device lifting mechanism, and place the sample on the lower heating plate.

[0019] (c) Lower the vacuum chamber and the upper heating plate, set the vacuum degree of the vacuum chamber and the temperature of the upper heating plate, apply pressure to the sample through the loading system, measure the thickness of the sample under different pressures through the pressure sensor and the displacement sensing device, and record the curve of pressure vs. sample thickness;

[0020] (d) Set the thickness or pressure value, set the heating-up curve for thermal conductivity testing, control the heating-up, and record the temperature, thickness, and heat flux information;

[0021] (e) After the temperatures on the upper and lower surfaces of the sample are stable, take the average temperature difference, thickness, and heat flux of a stable value period and calculate the thermal conductivity.

[0022] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0023] 1. The system of the present invention can in-situ measure and monitor the thickness and deformation of the sample through the displacement sensing device; it has a loading system, through which pressure can be applied to and released from the sample, the pressure applied to the surface of the sample can be adjusted at any time, and the pressure change can be monitored through the pressure sensor; the relationship between the pressure and displacement of the flexible material can be measured simultaneously.

[0024] 2. The upper and lower heating plates can be temperature-controlled, that is, the compression deformation measurement of the sample at a certain constant temperature can be realized, and the compression deformation measurement of the sample under a certain temperature gradient, vacuum degree, and atmosphere can also be realized; it can also be controlled by a program to simulate the compression deformation of the material under actual working conditions and the changes of the thermal conductivity with temperature, pressure, air pressure, etc. It is also possible to fix one parameter and change other parameters simultaneously to observe the performance changes of the material (such as fixing the air pressure, changing the loading pressure and temperature simultaneously according to the actual working conditions, and recording the thickness changes of the sample, etc.).

[0025] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination schemes. Other features and advantages of the present invention will be described in the subsequent specification, and some advantages can be made obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained from the content specifically pointed out in the specification and the drawings. Description of the Drawings

[0026] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation to the present invention. Throughout the drawings, the same reference signs represent the same components.

[0027] Figure 1 It is a multi-parameter controllable thermal conductivity testing system of the present invention.

[0028] Figure 2Schematic diagram of the upper heating plate and its accessory structure of the present invention.

[0029] Figure 3 Schematic diagram of the loading system of the present invention.

[0030] Figure 4 Schematic diagram of the lower heating plate and its accessory structure of the present invention

[0031] Figure 5 Temperature-time curve of Example 2.

[0032] Figure 6 Thermal conductivity-time curve of Example 2.

[0033] Reference numerals:

[0034] 1 - Upper heating plate; 2 - Lower heating plate; 3 - Loading head; 4 - Loading column; 401 - Upper loading column; 402 - Lower loading column; 5 - Pressure sensor; 6 - Displacement sensing device; 601 - Push rod; 602 - Displacement sensor; 603 - Low-expansion ceramic plate; 7 - Vacuum chamber; 8 - Spring; 9 - Thermocouple; 10 - Heat flux measuring device; 11 - Vacuum gauge; 12 - Thermal insulation layer; 13 - Mechanical pump; 14 - Molecular pump; 15 - Motor; 16 - Cross bar; 17 - Right-angle adapter; 18 - Lead screw; 19 - Vacuum chamber lifting mechanism; 20 - Loading device lifting mechanism; 21 - Flange; 22 - Sample; 23 - Bellows; 24 - Heating element; 25 - Heat sink plate; 26 - Water-cooling pipeline. Detailed implementation manners

[0035] The following combines the drawings to specifically describe the preferred embodiments of the present invention. Among them, the drawings form a part of this application and are used together with the embodiments of the present invention to explain the principle of the present invention, and are not used to limit the scope of the present invention.

[0036] Due to different equipment and principles, the test accuracies and measured temperature ranges of existing thermal conductivity test methods for thermal insulation materials are different. In the prior art, in order to ensure full contact between the sample and the heating element, usually a certain pressure is applied to the sample by the heating plate. Different methods and even different equipment apply different pressures to the sample, which will cause different deformation amounts of the sample and produce a large thickness change.

[0037] According to the Fourier one-dimensional heat conduction model, the calculation formula for the thermal conductivity is:

[0038]

[0039] In the formula:

[0040] q: Heat flux density, unit: W / m 2 ;

[0041] d: Sample thickness, unit: m;

[0042] ΔT: Temperature difference between the upper and lower plates, unit: °C or K;

[0043] λ: Thermal conductivity of the sample, unit: W / (m·K).

[0044] It can be seen from the above formula that under the same heat flow, the measured thermal conductivity is proportional to the thickness d value involved in the calculation. It is found in the experiment that the thickness value measured by the thickness gauge generally deviates by more than 10% from the thickness value measured after loading by the existing thermal conductivity testing instruments. There is also no unified requirement for the loading pressure in the existing testing methods for the thermal conductivity of flexible thermal insulation materials, resulting in the inability to evaluate the deviation of the thickness values measured by different methods and equipment, and causing a large error in the measurement results, which brings great uncertainty to the subsequent use of the material and the calculation of the thermal insulation layer structure.

[0045] Therefore, the present invention provides a multi-parameter controllable thermal conductivity testing system, as Figure 1-3 shown, which includes a heating system, a loading system, a measurement system and a vacuum system;

[0046] The heating system includes an upper heating plate 1 and a lower heating plate 2, the loading system includes a loading head 3 and a loading column 4 connected in sequence from top to bottom, the measurement system includes a pressure sensor 5 and a displacement sensing device 6, and the vacuum system includes a vacuum chamber 7;

[0047] The upper heating plate 1 and the lower heating plate 2 are arranged in the vacuum chamber 7, the upper heating plate 1 is located above the lower heating plate 2, the loading head 3 is located above the vacuum chamber 7, one end of the loading column 4 passes through the upper wall of the vacuum chamber 7 and is connected to the upper heating plate 1, the pressure sensor 5 is located on the loading head 3, the displacement sensing device 6 includes a displacement sensor 602 and a push rod 601 connected in sequence from top to bottom, the displacement sensor 602 is located above the vacuum chamber 7, and one end of the push rod 601 passes through the upper wall of the vacuum chamber 7 and is connected to the upper heating plate 1.

[0048] During implementation, the value of the displacement sensor 602 when the upper heating plate 1 and the lower heating plate 2 are in contact is set to zero. After placing the sample, the thickness of the sample is transmitted to the displacement sensor 602 through the top rod 601, and the thickness of the sample can be measured; by applying pressure or tension to the sample through the loading system, the thickness (deformation) of the sample under different pressures can be measured, and then the corresponding thermal conductivity coefficient can be measured. Since the upper heating plate 1 has its own weight, when it is necessary to reduce the pressure loaded on the sample surface, the upper heating plate 1 is lifted through the loading system. At this time, the pressure acting on the sample is the weight of the upper heating plate 1 itself minus the upward pulling force; when it is necessary to increase the pressure loaded on the sample surface, the upper heating plate 1 is pressed down through the loading system. At this time, the pressure acting on the sample is the weight of the upper heating plate 1 itself plus the downward pressing force, and both the pulling force and the downward pressure are monitored by the pressure sensor 5.

[0049] The system of the present invention can measure and monitor the thickness and deformation of the sample in situ through a displacement sensor device; it has a loading system, through which the sample can be pressurized and depressurized, the pressure loaded on the sample surface can be adjusted at any time, and the pressure change can be monitored through a pressure sensor; the relationship between the pressure and displacement of the flexible material can be measured simultaneously.

[0050] The system of the present invention can not only measure the performance of samples under multi-parameter changes, but also provide more reliable detection when detecting the thermal conductivity of samples alone. For example, the thermal conductivity of the flexible standard sample is 0.035W / (m·K) under room temperature and normal pressure without loading, and the test result of the GHP type thermal conductivity meter is 0.040W / (m·K). After measurement, the loading pressure of the GHP type is 70kgf, which causes the sample to be compressed. The thickness during the test is less than the thickness of the sample before loading, that is, the thickness involved in the calculation is greater than the actual thickness, resulting in a larger test result. When the system of the present invention is used to detect the thermal conductivity of the sample, when the sample is loaded with a pressure of 70kgf, the actual detection thickness is measured by a displacement sensor device, and the test result obtained is 0.036W / (m·K). This is because the sample is compressed, the gap is reduced, and the thermal conductivity increases; after complete unloading, the upper heating is controlled to just contact the sample, and the thermal conductivity value measured at this time is 0.035W / (m·K), which is consistent with the nominal value.

[0051] In the present invention, in order to ensure the airtightness of the connection between the displacement sensor device and the vacuum chamber 7, a bellows 23 is preferably provided between the displacement sensor device and the vacuum chamber 7. Similarly, a bellows 23 is also provided between the loading column 4 and the vacuum chamber 7.

[0052] By controlling the temperature of the upper and lower heating plates, the compression deformation measurement of the sample at a certain constant temperature can be achieved; the compression deformation measurement of the sample under a certain temperature gradient, vacuum degree and atmosphere can also be achieved; the compression deformation and thermal conductivity of the material under actual working conditions can also be simulated by program control, and the changes with temperature, pressure, air pressure, etc. can be observed; a certain parameter can be fixed while other parameters are changed to observe the performance changes of the material (such as fixing the air pressure, changing the loading pressure and temperature simultaneously according to the actual working conditions, and recording the thickness change of the sample, etc.).

[0053] The upper heating plate and the lower heating plate in the present invention can be conventional selections in the art. For example, the heating plate includes a heat insulation layer, a resistor and a heat sink plate. The resistor is arranged between the heat insulation layer and the heat sink plate. The side with the heat sink plate is the contact surface with the sample, and the sample is heated by the resistor generating heat; during the implementation process, only the upper heating plate 1 can be heated, or both the upper heating plate 1 and the lower heating plate 2 can be heated.

[0054] In the present invention, the displacement sensing device 6 can also be arranged inside the vacuum chamber 7, but cannot be arranged on the vacuum chamber 7, because the vacuum chamber will deform after being evacuated, affecting the displacement accuracy.

[0055] In the present invention, the ejector rod 601 is preferably made of a material with a low linear expansion coefficient to prevent the displacement change measured from being affected by the expansion of the ejector rod 601 due to the high-temperature thermal effect. Further preferably, as Figure 2 shown, the ejector rod 601 is connected to the upper heating plate 1 through a low-expansion ceramic plate 603.

[0056] In the present invention, the ejector rod 601 is used instead of an optical sensor because the optical sensor is easily interfered by air flow and vacuum degree, resulting in large deviations, while the ejector rod 601 and the displacement sensor 602 are applicable to the in-situ measurement of the sample thickness under various measurement conditions such as high temperature and vacuum.

[0057] In the present invention, the sensor can be an LVDT or a grating.

[0058] In the present invention, it is preferred to set two displacement sensing devices 6, which are respectively arranged at both ends of the upper heating plate to obtain more accurate measurement.

[0059] In the present invention, to improve the loading accuracy of the pulling force of the loading system on the upper heating plate 1, preferably, as Figure 3As shown, the loading system further includes a spring 8. The loading column 4 includes an upper loading column 401 and a lower loading column 402. The upper end of the upper loading column 401 is connected to the loading head 3. The lower end of the lower loading column 402 passes through the upper wall of the vacuum chamber 7 and is connected to the upper heating plate 1. A spring 8 is sleeved between the lower end of the upper loading column 401 and the upper end of the lower loading column 402. The upper end of the spring 8 is connected to the outer periphery of the lower end of the upper loading column 401, and the lower end of the spring 8 is connected to the outer periphery of the upper end of the lower loading column 402. In this preferred embodiment, when a tensile force is applied to the upper heating plate 1, it is transmitted through the spring 8, and the acting distance is extended by the spring 8 to improve the tensile force accuracy; when a pressure is applied to the lower heating plate 1, it is directly loaded through the direct contact between the upper loading column 401 and the lower loading column 402.

[0060] In the present invention, in order to conveniently control the loading system to lift and press down the upper heating plate 1, preferably, the loading system further includes a loading device lifting mechanism 20, and the loading device lifting mechanism 20 is arranged above the loading head 3 and is connected to the loading head 3.

[0061] In the present invention, the temperature measuring device on the upper and lower surfaces of the sample can be a conventional choice in the art. Preferably, the thermocouple 9 penetrates through the upper heating plate 1 and contacts the upper surface of the sample, and the thermocouple 9 penetrates through the lower heating plate 1 and contacts the lower surface of the sample.

[0062] In the present invention, the measuring system further includes a heat flux measuring device 10, and the heat flux measuring device 10 is arranged on the upper surface of the lower heating plate 2. When the lower heating plate 2 includes a heat sink plate, the heat flux measuring device 10 is arranged between the heat sink plate and the heating element. The heat flux measuring device 10 can be a conventional choice in the art. For example, the heat flux measuring device 10 is a heat flux meter or a water calorimeter.

[0063] Specifically, as Figure 4 shown, the lower heating plate 2 sequentially includes a heating element 24 (for example, a resistor) and a heat sink plate 25 from bottom to top, and the heat flux measuring device 10 is arranged between the heating element 24 and the heat sink plate 25.

[0064] In the present invention, the heat flux measuring device 10 can be set as a replaceable structure so as to replace the heat flux meter or the water calorimeter according to needs. For example, the lower part of the lower heating plate 2 is sealed and fixed through a flange 21 and a support assembly, and enough vacuum interfaces are left on the flange to facilitate the replacement of the circuit and the water circuit. Comparative analysis of different test methods can be carried out. Under the same loading pressure, the reliability of different test methods can be compared, and the loading pressures of different devices (such as the Netzsch HFM 436 device based on the heat flux meter method, the Netzsch GHP 456 device based on the guarded hot plate method, the self-developed device based on the heat flux meter method, etc.) can also be simulated to judge the influence of the loading pressure of the device itself on the measurement result.

[0065] In the present invention, preferably, the measurement system further includes a vacuum gauge 11, which is located outside the vacuum chamber 7 and communicates with the inside of the vacuum chamber 7. The vacuum gauge 11 is used to measure the pressure in the vacuum chamber 7.

[0066] In the present invention, in order to ensure a constant temperature during sample measurement, preferably, a heat insulation layer 12 is provided inside the vacuum chamber 7. The heat insulation layer 12 encloses a heat insulation cavity, and the upper heating plate 1 and the lower heating plate 2 are located in the heat insulation cavity.

[0067] In the present invention, the vacuum system further includes a mechanical pump 13 and / or a molecular pump 14, which communicate with the inside of the vacuum chamber 7. The mechanical pump 13 and / or the molecular pump 14 are used to control the pressure in the vacuum chamber 7. When both the mechanical pump 13 and the molecular pump 14 are provided, the molecular pump 14 is arranged between the mechanical pump 13 and the vacuum chamber 7.

[0068] The vacuum system may further include a gas backfill mechanism, a vacuum gauge, etc. The gas backfill mechanism can perform atmosphere backfill after vacuum pumping. By controlling the intake and exhaust gas volumes, a set constant air pressure can be maintained inside the vacuum chamber 7. The intake flow rate can also be adjusted to create a slightly positive pressure environment to prevent air from mixing in during tests under normal pressure.

[0069] In the present invention, the multi-parameter controllable thermal conductivity test system further includes a lifting system. The lifting system includes a motor 15, a cross bar 16, two right-angle adapters 17, two lead screws 18, and two vacuum chamber lifting mechanisms 19. The vacuum chamber lifting mechanisms 19 are respectively arranged on both sides of the vacuum chamber 7 and are connected to the vacuum chamber 7. The two ends of the cross bar 16 are respectively connected to the lead screws 18 through the right-angle adapters 17, and the lead screws 18 are respectively connected to the vacuum chamber lifting mechanisms 19. This lifting system is used to lift the vacuum chamber 7 when replacing samples or maintaining the equipment. At the same time, the loading system and the upper heating plate 1 are lifted together by the loading device lifting mechanism 20.

[0070] In the present invention, the multi-parameter controllable thermal conductivity test system further includes a circulating cooling system and a control system. The circulating cooling system includes a water chiller and a water cooling pipeline 26, which cools the upper and lower heating plates and the vacuum chamber to prevent the system from overheating. The control system is connected to the heating system, the loading system, the measurement system, the vacuum system, the lifting system, and the circulating cooling system. The main function of the control system is to collect various parameters obtained, and it can set and program the temperature rise and loading curves, and calculate the measurement result curve of the thermal conductivity from the collected data.

[0071] On the other hand, the present invention provides a method for testing the thermal conductivity with multi-parameter controllability. Using the multi-parameter controllable thermal conductivity testing system of the present invention, this method for testing the thermal conductivity with multi-parameter controllability includes:

[0072] (a) Adjust the sample state and record the initial thickness; and set the value of the displacement sensor when the upper heating plate 1 and the lower heating plate 2 are in contact to zero;

[0073] (b) Lift the vacuum chamber 7 through the vacuum chamber lifting mechanism 19, and at the same time lift the upper heating plate 1 through the loading device lifting mechanism 20, and place the sample on the lower heating plate 2;

[0074] (c) Lower the vacuum chamber 7 and the upper heating plate 1, set the vacuum degree of the vacuum chamber 7 and the temperature of the upper heating plate 1, apply pressure to the sample through the loading system, measure the sample thickness under different pressures through the pressure sensor 5 and the displacement sensing device 6, and record the curve of pressure and sample thickness;

[0075] (d) Set the thickness or pressure value, set the heating-up curve for thermal conductivity testing, control the heating-up, and record the temperature, thickness, and heat flux information;

[0076] (e) After the temperatures on the upper and lower surfaces of the sample are stable, take the average temperature difference, thickness, and heat flux of a stable value section and calculate the thermal conductivity.

[0077] In the present invention, according to the common testing methods, equipment, and testing standards (GB / T 10294 and 10295) for thermal insulation materials, the size of the sample for testing the thermal conductivity of common thermal insulation materials is 300 mm * 300 mm, and the sample thickness is less than 50 mm.

[0078] Next, the multi-parameter controllable thermal conductivity testing system and method of the present invention will be further described through specific embodiments.

[0079] In the following Examples 1-2, the sample is mullite asbestos felt with an initial thickness of 25 mm.

[0080] Example 1

[0081] Measure the thermal conductivity at a thickness of 5 - 50 mm.

[0082] (a) And set the value of the displacement sensor when the upper heating plate 1 and the lower heating plate 2 are in contact to zero;

[0083] (b) Lift the vacuum chamber 7 through the vacuum chamber lifting mechanism 19, and at the same time lift the upper heating plate 1 through the loading device lifting mechanism 20, and place the sample on the lower heating plate 2;

[0084] (c) Lower the vacuum chamber 7 and the upper heating plate 1, set the vacuum degree of the vacuum chamber 7 and the temperature of the upper heating plate 1, apply pressure to the sample through the loading system (such as 50 kgf), measure the thickness at different pressures through the pressure sensor 5 and the displacement sensing device 6, and record the curve of pressure and thickness;

[0085] (d) Adjust the sample thickness value, set the heating rate curve for thermal conductivity testing, control the heating, and record the temperature, thickness, and heat flux information;

[0086] (e) After the temperatures on the upper and lower surfaces of the sample are stabilized, take the average temperature difference, thickness, and heat flux of a stable value segment and calculate the thermal conductivity.

[0087] Example 2

[0088] Measure the relationship between the sample temperature and the thermal conductivity.

[0089] (a) Set the value of the displacement sensor when the upper heating plate 1 and the lower heating plate 2 are in contact to zero;

[0090] (b) Lift the vacuum chamber 7 through the vacuum chamber lifting mechanism 19, and at the same time lift the upper heating plate 1 through the loading device lifting mechanism 20, and place the sample on the lower heating plate 2;

[0091] (c) Lower the vacuum chamber 7 and the upper heating plate 1, set the air pressure: 100 kPa, without loading, thickness 25 mm, loading pressure 60 kgf, thickness 22 mm; temperature range 200 - 900 °C; the test temperature curve is as Figure 5 shown;

[0092] (d) Test the apparent thermal conductivity curve and results, as Figure 6 shown. The thermal conductivities at different temperatures are listed in Table 1 (with and without loading pressure):

[0093] Table 1

[0094] 200℃ 400℃ 600℃ 800℃ 900℃ λ (unloaded) 0.0283 0.0382 0.0616 0.1044 0.1334 λ (loaded) 0.0296 0.0443 0.0716 0.1134 0.1430

[0095] Examples 3 - 7

[0096] Use the test system of Examples 3 - 7 of the present invention to test the different deformation pressures of mullite asbestos felts with different initial thicknesses, and the results are shown in Table 2.

[0097] Table 2

[0098] Sample number 10% deformation pressure / N 30% deformation pressure / N 50% deformation pressure / N Initial thickness / mm Example 3 86.49 718.2 4167 22.89 Example 4 123.3 1044 5490 23.35 Example 5 92.7 707.4 3951 22.55 Example 6 103.5 927 5382 23.18 Example 7 165.6 1404 7155 23.34

[0099] As can be seen from Table 2, the measurement system of the present invention can measure the compression deformation amount of the sample under different pressures.

[0100] As described above, it is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A multi-parameter controllable thermal conductivity testing system, characterized in that It includes a heating system, a loading system, a measuring system, and a vacuum system; The heating system includes an upper heating plate (1) and a lower heating plate (2), the loading system includes a loading head (3) and a loading column (4) connected in sequence from top to bottom, the measuring system includes a pressure sensor (5) and a displacement sensing device (6), and the vacuum system includes a vacuum chamber (7); The upper heating plate (1) and the lower heating plate (2) are arranged in the vacuum chamber (7), the upper heating plate (1) is located above the lower heating plate (2), the loading head (3) is located above the vacuum chamber (7), one end of the loading column (4) passes through the upper wall of the vacuum chamber (7) and is connected to the upper heating plate (1), the pressure sensor (5) is located on the loading head (3), the displacement sensing device (6) includes a displacement sensor (602) and a push rod (601) connected in sequence from top to bottom, the displacement sensor (602) is located above the vacuum chamber (7), and one end of the push rod (601) passes through the upper wall of the vacuum chamber (7) and is connected to the upper heating plate (1); The loading system further includes a spring (8), the loading column (4) includes an upper loading column (401) and a lower loading column (402), the upper end of the upper loading column (401) is connected to the loading head (3), the lower end of the lower loading column (402) passes through the upper wall of the vacuum chamber (7) and is connected to the upper heating plate (1), the spring (8) is sleeved on the lower end of the upper loading column (401) and the upper end of the lower loading column (402), the upper end of the spring (8) is connected to the outer periphery of the lower end of the upper loading column (401), and the lower end of the spring (8) is connected to the outer periphery of the upper end of the lower loading column (402); The loading system further includes a loading device lifting mechanism (20), and the loading device lifting mechanism (20) is arranged above the loading head (3) and connected to the loading head (3); The multi-parameter controllable thermal conductivity test system further includes a lifting system, the lifting system includes a motor (15), a cross bar (16), two right-angle adapters (17), two lead screws (18), and two vacuum chamber lifting mechanisms (19), the vacuum chamber lifting mechanisms (19) are respectively arranged on both sides of the vacuum chamber (7) and connected to the vacuum chamber (7), both ends of the cross bar (16) are respectively connected to the lead screws (18) through the right-angle adapters (17), and the lead screws (18) are respectively connected to the vacuum chamber lifting mechanisms (19).

2. The multi-parameter controllable thermal conductivity testing system according to claim 1, wherein The measuring system further includes a thermocouple (9), the thermocouple (9) penetrates the upper heating plate (1) and contacts the upper surface of the sample, and the thermocouple (9) penetrates the lower heating plate (2) and contacts the lower surface of the sample.

3. The multi-parameter controllable thermal conductivity test system according to claim 2, wherein The measuring system further includes a heat flux measuring device (10), and the heat flux measuring device (10) is arranged on the upper surface of the lower heating plate (2).

4. The multi-parameter controllable thermal conductivity testing system according to claim 3, wherein The measuring system further includes a vacuum gauge (11), the vacuum gauge (11) is located outside the vacuum chamber (7) and is communicated with the inside of the vacuum chamber (7).

5. The multi-parameter controllable thermal conductivity testing system according to claim 1, characterized in that, An insulating layer (12) is provided inside the vacuum chamber (7). The insulating layer (12) encloses an insulating cavity, and the upper heating plate (1) and the lower heating plate (2) are located in the insulating cavity.

6. The multi-parameter controllable thermal conductivity testing system according to claim 1, wherein The vacuum system further includes a mechanical pump (13) and / or a molecular pump (14), and the mechanical pump (13) and / or the molecular pump (14) is / are in communication with the interior of the vacuum chamber (7).

7. A multi-parameter controllable thermal conductivity testing method, characterized in that, Using the multi-parameter controllable thermal conductivity testing system according to any one of claims 1-6, the multi-parameter controllable thermal conductivity testing method includes: (a) Adjust the sample state and record the initial thickness; and set the value of the displacement sensor when the upper heating plate (1) and the lower heating plate (2) are in contact to zero. (b) Lift the vacuum chamber (7) through the vacuum chamber lifting mechanism (19), and at the same time lift the upper heating plate (1) through the loading device lifting mechanism (20), and place the sample on the lower heating plate (2). (c) Lower the vacuum chamber (7) and the upper heating plate (1), set the vacuum degree of the vacuum chamber (7) and the temperature of the upper heating plate (1), apply pressure to the sample through the loading system, and measure the sample thickness at different pressures through the pressure sensor (5) and the displacement sensing device (6), and record the curve of pressure and sample thickness. (d) Set the thickness or pressure value, set the heating-up curve for thermal conductivity testing, control the heating-up, and record the temperature, thickness, and heat flux information. (e) After the temperatures on the upper and lower surfaces of the sample are stable, take a temperature difference, thickness, and heat flux of a stable value section and calculate the average thermal conductivity.

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