Device for detecting heat conductivity coefficient of powder
By designing a device including a graphite crucible, a graphite top cover, an insulation layer, a graphite blind tube, a heating mechanism and an infrared thermometer, the problem of the prior art being difficult to accurately detect the thermal conductivity of the powder at high temperatures is solved, and accurate measurement and real-time monitoring of the thermal conductivity of the powder and materials during the reaction process are achieved.
Patent Information
- Application Number
- CN202421832408.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-30
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-07-30
AI Technical Summary
The prior art is difficult to accurately detect the powder thermal conductivity in a loose state at high temperatures, and it is impossible to detect changes in the thermal conductivity of the material during the reaction process in real time, and is easily affected by reaction corrosion.
A device including a graphite crucible, a graphite top cover, an insulation layer, a graphite blind tube, a heating mechanism and an infrared thermometer are designed. It can detect the thermal conductivity of the powder at a high temperature of 700 to 3000°C, and accurately measure the thermal conductivity through a graphite blind tube and an infrared thermometer.
The device can accurately detect the powder thermal conductivity in the loose state at high temperature, avoid errors after compacting the sample, and can detect changes in the thermal conductivity of the powder material before and after the reaction in real time, avoiding the impact of reaction corrosion.
Smart Images
Figure CN222979510U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a device for detecting the thermal conductivity of powder, belonging to the technical field of powder thermal conductivity testing. Background Art
[0002] The traditional method for detecting the thermal conductivity of powder samples is the hot plate method. Two hot plates are respectively applied to two surfaces of the object to be measured to establish a heat exchange system. By fixing the temperature of one hot plate and measuring the temperature of the other hot plate, the thermal conductivity of the substance can be calculated. The disadvantages of this method are as follows: 1) The powder sample needs to be pressed into a mold, and the thermal conductivity of the powder material in the loose state cannot be measured; 2) The detection temperature is usually -40°C to 700°C, and the thermal conductivity of materials above 2000°C cannot be detected; 3) The change in the thermal conductivity of the material during the reaction process cannot be detected.
[0003] Currently, some researchers detect the thermal conductivity of powder in the loose state through the probe method. The powder is heated by the probe, and the temperature and resistance of the probe during the heating process are collected, and then the thermal conductivity of the powder is obtained by combining with a pre-calculation model. Although this method can solve the first disadvantage of the hot plate method, as the temperature rises, the resistance of the probe is greatly affected, and the thermal conductivity of the powder at high temperatures still cannot be accurately measured; in addition, when detecting the thermal conductivity of the material during some reaction processes, the probe is easily corroded by the reaction or has a negative impact on the reaction of the material, thus limiting the detection of the thermal conductivity of the material during the reaction process by this method. Content of the Utility Model
[0004] In order to solve the above problems, the present application proposes a device for detecting the thermal conductivity of powder. This device can accurately measure the thermal conductivity of loose powder materials at 700 - 3000°C, and will not be corroded by the reaction or affect the normal reaction of the material, so the change in the thermal conductivity of the powder material before and after the reaction can be accurately measured.
[0005] The present application provides a device for detecting the thermal conductivity of powder, which includes:
[0006] A graphite crucible, the interior of which is hollow to form a loading area for filling powder, and a loading port is provided at the top;
[0007] A graphite upper cover, which is used to cover the loading port, and a first through hole is provided on the graphite upper cover;
[0008] A heat insulation layer, which is arranged outside the graphite crucible and the graphite upper cover, and a second through hole communicating with the first through hole is provided on the heat insulation layer;
[0009] A graphite blind tube, the closed end of the graphite blind tube passes through the first through hole and the second through hole and is arranged in the charging area, and the open end is arranged outside the heat preservation layer;
[0010] A heating mechanism for heating the charging area;
[0011] An infrared thermometer for detecting the temperature at the bottom of the graphite blind tube or on the graphite crucible.
[0012] Optionally, the inner height h of the graphite crucible 0 is 50 - 600 mm, and the inner radius r of the graphite crucible 0 is 20 - 200 mm.
[0013] Optionally, the outer radius r of the graphite blind tube 1 is 8 - 20 mm, and r 1 < r 0 - 5 mm.
[0014] Optionally, the wall thickness of the graphite blind tube is 2 - 5 mm.
[0015] Optionally, the length h of the graphite blind tube extending into the charging area 1 is 0.25 - 0.75 times the inner height h of the graphite crucible 0 .
[0016] Optionally, the infrared thermometer is aligned with the central axis of the graphite blind tube.
[0017] Optionally, an infrared temperature measurement channel is further provided on the side surface of the graphite crucible and the heat preservation layer, and the central lines of the infrared temperature measurement channel, the infrared thermometer, and the bottom of the graphite blind tube are flush.
[0018] Optionally, the first through hole and the graphite crucible are arranged on the same central axis.
[0019] Optionally, the thicknesses of the graphite crucible and the graphite upper cover are 5 - 10 mm.
[0020] Optionally, the heat preservation layer includes an upper heat preservation layer and an outer heat preservation layer, the outer heat preservation layer is wrapped outside the graphite crucible, and the upper heat preservation layer is arranged above the graphite upper cover.
[0021] The beneficial effects that can be produced by this application include but are not limited to:
[0022] 1. The device for detecting the thermal conductivity of powder provided by this application can detect the thermal conductivity of powder samples in a loose state at a high temperature of 700 - 3000 °C, avoiding the problem that the coefficient measured after compacting the sample is inconsistent with the thermal conductivity of the powder sample in the actual tooling state.
[0023] 2. The device provided by the present application for detecting the thermal conductivity of powder will not be subject to reaction corrosion or affect the normal reaction of the material. Therefore, it can accurately measure the change in the thermal conductivity of the powder material before and after the reaction in real time, facilitating researchers to analyze the reaction process.
[0024] 3. For the device provided by the present application for detecting the thermal conductivity of powder, the size settings of the graphite crucible and the graphite blind tube can improve the temperature uniformity of the powder material in the loading area, while reducing the interference of external factors and improving the accuracy of detection. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:
[0026] Figure 1 It is a schematic structural diagram of the device for detecting the thermal conductivity of powder according to Embodiment 1 of the present application;
[0027] Figure 2 It is a schematic structural diagram of the device for detecting the thermal conductivity of powder according to Embodiment 2 of the present application;
[0028] List of components and reference numerals:
[0029] 1. Upper insulation layer; 2. Outer insulation layer; 3. Graphite blind tube; 4. Graphite upper cover; 5. Graphite crucible; 6. Infrared temperature measurement channel; 7. Loading area. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0030] In order to more clearly illustrate the overall concept of the present application, the following will be described in detail by way of examples in conjunction with the drawings of the specification.
[0031] In order to be able to more clearly understand the above-mentioned objects, features and advantages of the present application, the present application will be further described in detail below in conjunction with the drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.
[0032] Many specific details are set forth in the following description in order to provide a thorough understanding of the present application. However, the present application may be implemented in other ways different from those described herein. Therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.
[0033] In addition, in the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present application.
[0034] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise specifically defined.
[0035] In the present application, unless otherwise clearly defined and limited, the terms such as "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.
[0036] In the present application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0037] Embodiment 1
[0038] Reference Figure 1, embodiments of the present application disclose a device for detecting the thermal conductivity of powder, comprising: a graphite crucible 5, the interior of the graphite crucible 5 is hollow to form a loading area 7 for loading powder, and a loading port is provided at the top; a graphite upper cover 4, the graphite upper cover 4 is used to cover the loading port, and a first through hole is provided on the graphite upper cover 4; a thermal insulation layer, the thermal insulation layer is provided outside the graphite crucible 5 and the graphite upper cover 4, and the thermal insulation layer is provided with a second through hole communicating with the first through hole; a graphite blind tube 3, the closed end of the graphite blind tube 3 passes through the first through hole and the second through hole and is arranged in the loading area 7, and the open end is arranged outside the thermal insulation layer; a heating mechanism, the heating mechanism is used to heat the loading area 7; an infrared thermometer, the infrared thermometer is used to detect the temperature at the bottom of the graphite blind tube 3 or on the graphite crucible 5.
[0039] During the use of the device, the powder material is loaded into the loading area 7 of the graphite crucible 5 through the loading port, and then the graphite upper cover 4 is covered, and the closed end of the graphite blind tube 3 is inserted into the loading area 7. Under the action of the heating mechanism, heating inside the graphite crucible 5 is realized. By using the infrared thermometer to measure the temperature between two points, the thermal conductivity of the powder can be calculated according to Fourier's law Q = KAΔT / d, where K = Qd / AΔT. In the above formula, Q is the heat, K is the thermal conductivity, A is the contact area, d is the heat transfer distance, and ΔT is the temperature difference.
[0040] Reference Figure 1 , during the temperature measurement process of the device, the powder is heated by the heating mechanism with a constant power P, and this power P is the heat Q per unit time. When the depth h of the graphite blind tube 3 in the graphite crucible 5 11 , the temperature at the bottom of the graphite blind tube 3 is measured by the infrared thermometer. After the temperature is constant, the temperature reading is recorded as T 1 , then the depth h of the graphite blind tube 3 in the graphite crucible 5 is adjusted through mechanical tooling or manually 12 , and the infrared thermometer continues to measure the temperature at the bottom of the graphite blind tube 3. After the reading of the infrared thermometer is stable again, the temperature reading T is recorded 2 , then the calculation formula for the thermal conductivity can be deduced as: K = P(h 11 - h 12 ) / [πr 1 2 (T 1 - T 2 )], where r 1 is the outer radius of the graphite blind tube 3, and πr 1 2 is the bottom area of the graphite blind tube 3. According to the above calculation formula, the thermal conductivity of the powder in a loose state can be measured through the temperature and the depth movement distance at different depths of the graphite blind tube 3 in the graphite crucible 5.
[0041] Specifically, during the above detection process, the distance between the powder in the loading area 7 and the graphite upper cover 4 is an air layer. The existence of the air layer may affect the detection result of the thermal conductivity of the powder. Therefore, in actual use, the gap between the powder in the loading area 7 and the graphite upper cover 4 is ≤ 5 mm. This setting can not only reduce the influence of the air layer on the detection result, but also reserve a certain space for the insertion of the graphite blind tube 3 to avoid powder overflow. A more preferred solution is that when the graphite blind tube 3 is inserted into the loading area 7, the gap between the powder and the graphite upper cover 4 is close to or equal to 0, that is, the powder fills the entire loading area 7.
[0042] The device uses a graphite crucible 5 and a graphite blind tube 3, which can accurately detect the thermal conductivity of the powder at 700 - 3000 °C. Moreover, the above materials will not be corroded during the powder reaction and will not affect the normal reaction of the material. Therefore, the change in thermal conductivity before and after the reaction can be detected. At the same time, under the heating of the heating mechanism, the graphite crucible 5 and the graphite blind tube 3 can also heat the material, which can improve the temperature uniformity of the powder material in the loading area 7 and make the temperature of the powder tend to a stable state faster, thereby improving the detection accuracy and detection efficiency.
[0043] Specifically, the heating mechanism is not shown in the figure. This structure and heating method can adopt the existing methods in the prior art, such as using an induction heating furnace for heating.
[0044] As a preferred embodiment, the inner height h of the graphite crucible 5 0 is 50 - 600 mm, and the inner radius r of the graphite crucible 5 0 is 20 - 200 mm. The size of this graphite crucible 5 determines the maximum capacity of the powder material contained in the device. In the case where the powder material needs to be basically filled, this size can save the usage amount of the powder material and reduce the detection cost; in the case of detecting the same material, this size can improve the loading ratio of the powder material in the loading area 7 compared with a large-size graphite crucible 5, thereby improving the detection accuracy.
[0045] As a preferred embodiment, the outer radius r of the graphite blind tube 3 1 is 8 - 20 mm, and r 1 < r 0 - 5 mm. The minimum outer radius of the graphite blind tube 3 is 8 mm to improve the detection accuracy and operability of the infrared thermometer, reduce the operation difficulty, and improve the detection efficiency and detection accuracy; the minimum outer radius of the graphite blind tube 3 is at least 5 mm smaller than the inner radius of the graphite crucible 5 to increase the amount of powder material between the graphite blind tube 3 and the graphite crucible 5. If the gap between the graphite crucible 5 and the graphite blind tube 3 is too small, the powder filled in the gap is too little, and local high temperature is likely to occur, reducing the detection accuracy of the device.
[0046] As an implementation manner, the wall thickness of the graphite blind tube 3 is 2 - 5 mm. The wall thickness of the graphite blind tube 3 affects the size of the inner radius of the graphite blind tube 3. The infrared thermometer performs infrared detection from the inside of the graphite blind tube 3 to its bottom. In this setting, the stability of the infrared thermometer for detecting the bottom of the graphite blind tube 3 can be improved, temperature deviation can be avoided, and thus the practicability of the device can be enhanced.
[0047] As an implementation manner, the length h of the graphite blind tube 3 extending into the charging area 7 1 is 0.25 - 0.75 times the inner height h 0 of the graphite crucible 5. Under the above detection method, both h 11 and h 12 are within this range. In this setting, it is possible to detect the powder material in the middle area of the graphite crucible 5. The temperature consistency of the powder material in the middle area is high, and it is less affected by external interference factors. Therefore, the detection accuracy can be improved. At the same time, when detecting the thermal conductivity coefficient of the powder during the reaction process, the powder material in the middle area reacts more thoroughly, and the reaction degree of the powder can be more reflected. Therefore, this setting is more convenient for detecting the change of the thermal conductivity coefficient of the powder during the reaction process.
[0048] As an implementation manner, the first through hole and the graphite crucible 5 are arranged on the same central axis. In this setting, the graphite blind tube 3 is arranged at the center of the graphite crucible 5. Therefore, it is to detect the powder material in the central area, combined with the length h 1 of the graphite blind tube 3 extending into the charging area 7, further improving the detection accuracy of the powder material.
[0049] As an implementation manner, the infrared thermometer is aligned with the center line of the graphite blind tube 3. In this setting, before and after the graphite blind tube 3 moves, the infrared thermometer directly detects the temperature at the center position of the graphite blind tube 3, avoiding detection deviation caused by different detection positions, and further improving the detection accuracy at high temperatures.
[0050] As an implementation manner, the thickness of the graphite crucible 5 and the graphite upper cover 4 is 5 - 10 mm. In the presence of the heating mechanism, this thickness can ensure heat transfer to the powder material, improve the heating efficiency of the powder material, and also ensure the stability and safety of the device, extending the service life of the device.
[0051] As an implementation manner, the heat insulation layer includes an upper heat insulation layer 1 and an outer heat insulation layer 2. The outer heat insulation layer 2 is wrapped around the outside of the graphite crucible 5, and the upper heat insulation layer 1 is arranged above the graphite upper cover 4. In actual use, the outer heat insulation layer 2 is fixed to the graphite crucible 5. When loading materials, the upper heat insulation layer 1 and the graphite upper cover 4 are removed, and materials can be loaded from the loading port. This setting can improve the convenience of using the device.
[0052] Specifically, the thicknesses of the upper thermal insulation layer 1 and the outer thermal insulation layer 2 are not limited. It is necessary to determine them by detecting factors such as temperature, powder properties, and thermal insulation layer materials. As long as the thermal insulation function can be achieved and it does not prevent the heating mechanism from heating the powder in the graphite crucible 5, it is fine.
[0053] Example 2
[0054] Reference Figure 2 , the difference between the device for detecting the thermal conductivity of the powder in this embodiment and that in Example 1 is that an infrared temperature measurement channel 6 is further provided on the side of the graphite crucible 5 and the thermal insulation layer. The center line of the infrared temperature measurement channel 6, the infrared thermometer, and the bottom of the graphite blind tube 3 are flush.
[0055] Under this setting, it is possible to detect the thermal conductivity of the powder without moving the graphite blind tube 3. After the heating mechanism heats to make the temperature of the system constant, due to the existence of the infrared temperature measurement channel 6, the infrared thermometer can be used to measure the temperature of the powder at the side wall of the graphite crucible 5 as the temperature of the first point. Record this temperature as T1. Then, use the infrared thermometer to measure the temperature at the bottom of the graphite blind tube 3 as the temperature of the second point. Record this temperature as T2. Then, the calculation formula for the thermal conductivity can be deduced as: K = P(r 0 -r 1 ) / [πr 1 2 (T 1 -T 2 )].
[0056] As an implementation manner, the radius r 2 of the infrared temperature measurement channel 6 is 5 - 15 mm. Under this setting, it can not only meet the accurate temperature measurement of the infrared thermometer but also avoid the influence of the infrared temperature measurement channel 6 on the powder.
[0057] As an implementation manner, the radius r 2 of the infrared temperature measurement channel 6 is the same as the radius r 1 of the graphite blind tube 3. This is not only beneficial to the shaping of the device but also beneficial to the calculation of the thermal conductivity.
[0058] The device for detecting the thermal conductivity of the powder in this application is applicable to testing various non-oxide powders and their mixtures, such as: silicon carbide powder, graphite powder, silicon powder, diamond powder, boron nitride powder, and mixtures of any two or more of the above powders, etc.
[0059] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for the relevant parts, reference can be made to the partial description of the method embodiment.
[0060] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various modifications and changes can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.
Claims
1. A device for detecting thermal conductivity of powder, characterized in that: include: A graphite crucible, wherein the interior of the graphite crucible is hollow to form a loading area for loading powder, and a loading port is provided on the top; A graphite upper cover, the graphite upper cover is used to cover the charging port, and the graphite upper cover is provided with a first through hole; A heat-insulating layer, wherein the heat-insulating layer is arranged outside the graphite crucible and the graphite upper cover, and the heat-insulating layer is provided with a second through hole communicating with the first through hole; A graphite blind tube, wherein the closed end of the graphite blind tube passes through the first through hole and the second through hole and is arranged in the charging area, and the open end is arranged outside the thermal insulation layer; A heating mechanism, the heating mechanism is used to heat the charging area; An infrared thermometer is used to detect the temperature at the bottom of a graphite blind tube or on a graphite crucible.
2. The device for detecting thermal conductivity of powder according to claim 1, characterized in that: The inner height h0 of the graphite crucible is 50-600 mm, and the inner radius r0 of the graphite crucible is 20-200 mm.
3. The device for detecting thermal conductivity of powder according to claim 2, characterized in that: The outer radius r1 of the graphite blind tube is 8-20 mm, and r1 <r0-5mm。 4. The device for detecting thermal conductivity of powder according to claim 3, characterized in that: The wall thickness of the graphite blind tube is 2-5 mm.
5. The device for detecting thermal conductivity of powder according to claim 4, characterized in that: The length h1 of the graphite blind tube extending into the charging area is 0.25-0.75 times the inner height h0 of the graphite crucible.
6. The device for detecting thermal conductivity of powder according to any one of claims 1 to 5, characterized in that: The infrared thermometer is aligned with the center line of the graphite blind tube.
7. The device for detecting thermal conductivity of powder according to any one of claims 1 to 5, characterized in that: An infrared temperature measurement channel is also provided on the side surface and the insulation layer of the graphite crucible, and the center line of the infrared temperature measurement channel, the infrared thermometer and the bottom of the graphite blind tube are flush.
8. The device for detecting thermal conductivity of powder according to any one of claims 1 to 5, characterized in that: The first through hole and the graphite crucible are arranged along a common central axis.
9. The device for detecting thermal conductivity of powder according to any one of claims 1 to 5, characterized in that: The thickness of the graphite crucible and the graphite upper cover is 5-10 mm.
10. The device for detecting thermal conductivity of powder according to any one of claims 1 to 5, characterized in that: The thermal insulation layer comprises an upper thermal insulation layer and an outer thermal insulation layer, wherein the outer thermal insulation layer is coated on the outer side of the graphite crucible, and the upper thermal insulation layer is arranged above the graphite upper cover.