A method and device for testing thermal insulation performance

Abstract

A method and device for testing thermal insulation performance, belonging to the field of thermal conductivity measuring equipment. The thermal insulation performance testing device can be used in conjunction with a test box, and comprises a frame, a thermal insulation sleeve, a first temperature measuring element and a second temperature measuring element. The thermal insulation sleeve, the test box, the first temperature measuring element and the second temperature measuring element are all fixed directly or indirectly on the frame. The device is easy to operate and cannot be damaged.

Description

Technical Field

[0001] The present application relates to the field of thermal conductivity measurement equipment, and in particular, to a method and equipment for testing thermal insulation performance. Background Art

[0002] Release agents are used as an interface layer between two surfaces that are easy to stick to each other. Release agents can make it easy for two objects to separate and keep the surface smooth and clean. In different fields of use, release agents have different functional requirements - stability, chemical inertness, heat resistance, etc. For example, in the casting field, release agents need to have various properties such as chemical stability, heat resistance, etc. Therefore, when choosing a release agent, how to effectively measure the thermal insulation performance of the release agent is an issue that needs to be carefully considered.

[0003] In view of this, this application is hereby filed. Summary of the invention

[0004] In order to improve or even solve the problem of evaluating the thermal insulation performance of a release agent, the present application proposes a method and equipment for testing the thermal insulation performance.

[0005] This application is implemented as follows:

[0006] In a first aspect, an example of the present application provides a thermal insulation performance testing device for use with a test box, comprising: a frame, a hollow thermal insulation sleeve, a non-contact first temperature measuring element and a second temperature measuring element. The thermal insulation sleeve is placed on the frame. The test box has a receiving cavity with an opening defined by a side wall and a bottom wall. The thermal insulation sleeve is configured to allow the test box to be embedded through the side wall and expose the outer surface of the opening and the bottom wall. The first temperature measuring element is connected to the frame and is used to measure the temperature through the opening. The second temperature measuring element is connected to the frame and is used to measure the temperature from the outer surface of the bottom wall.

[0007] The first temperature measuring element and the second temperature measuring element in the example of the present application are both physically isolated from the accommodating chamber of the test box, and therefore can be protected from thermal damage by the high-temperature material contained in the accommodating chamber during the test process. Based on this, when the measurement object is a high-temperature molten material (low-temperature solidified), the scheme can measure the above-mentioned material in the molten and solidified states respectively, so it has a wider applicability. At the same time, since the first temperature measuring element and the second temperature measuring element are independent of the test box, the setting of the test object and the high-temperature material in the test box will not interfere with the normal measurement of the two temperature measuring elements, so the measurement can be real-time, accurate, and continuous.

[0008] According to some examples of the present application, the non-contact first temperature measuring element is an infrared sensor temperature sensor. Optionally, the thermal insulation performance testing equipment has a temperature measuring bracket connected to the frame, and the non-contact first temperature measuring element is fixed by the temperature measuring bracket.

[0009] Infrared sensor thermometer has the advantages of high temperature measurement sensitivity and the ability to measure temperature at a long distance. The temperature measuring bracket helps to fix the posture of the infrared sensor thermometer, thereby maintaining the consistency of its temperature measurement position and thus improving the temperature measurement accuracy.

[0010] According to some examples of the present application, the second temperature measuring element is a thermocouple. Optionally, the thermal insulation performance testing device has a cover plate, and the thermocouple is pressed onto the outer surface of the bottom wall through the cover plate so that the thermocouple contacts the outer surface.

[0011] Thermocouple is a common temperature measuring element, which is easy to assemble, easy to replace, shock-resistant and has a wide temperature measuring range. The cover can make the probe of the second temperature measuring element in close contact with the bottom of the test box, which is more conducive to temperature transmission and more accurate temperature.

[0012] According to some examples of the present application, the thermal insulation performance testing device has a fixing sleeve connected to the frame, and the thermal insulation sleeve is embedded in the fixing sleeve to limit the test box.

[0013] The fixing sleeve has the function of limiting and fixing the heat insulation sleeve and the test box therein.

[0014] According to some examples of the present application, the thermal insulation performance testing equipment has a base, the base is connected to the frame, the base is connected to the fixed sleeve, a cover plate for crimping the thermocouple is configured on the base, and the cover plate is constructed to crimp the second temperature measuring element to the outer surface of the bottom wall.

[0015] The base can make the cover plate more stable, thereby improving its limiting effect on the second temperature measuring element.

[0016] According to some examples of the present application, the cover plate has a limiting structure, and the limiting structure is located on the contact side of the cover plate with the outer surface of the bottom wall, and the limiting structure is used to accommodate the second temperature measuring element. Optionally, the limiting structure is a groove. Optionally, the groove extends to the middle of the outer surface of the bottom wall.

[0017] The limiting structure makes it difficult for relative displacement to occur between the second temperature measuring element and the cover plate, thereby ensuring the consistency of the temperature measuring position and also helping to improve the accuracy of temperature measurement. The limiting method is simple and easy to operate.

[0018] According to some examples of the present application, the fixing sleeve has a stopper for constraining the heat insulating sleeve, and the fixing sleeve exposes the outer surface of the bottom wall of the test box through the stopper.

[0019] The fixing sleeve is provided with a stopper, so that the heat insulation sleeve embedded with the test box can be directly inserted into the fixing sleeve and limited by the stopper without the need for an additional fixing structure (such as bolts, etc.), thereby simplifying the structure and facilitating assembly to a certain extent.

[0020] According to some examples of the present application, the cover plate is liftably disposed on the base.

[0021] The cover plate is constructed in a lifting manner, which can facilitate the use of second temperature measuring elements of different models and specifications to a certain extent, and can also conveniently adjust the clamping force of the cover plate on the second temperature measuring element.

[0022] Optionally, the base includes: a base body and a lifting mechanism, wherein the base body has an internal cavity, the lifting mechanism cooperates with the base body and is located in the internal cavity, and the lifting mechanism is used to drive the cover plate to approach or move away from the bottom wall.

[0023] Optionally, the lifting mechanism includes a partition and a lifter; the partition is connected to the inner wall of the base body, and the partition has a threaded hole; the lifter has a lifting plate and a stud connected to each other, and the stud cooperates with the threaded hole.

[0024] In a second aspect, an example of the present application provides a method for measuring the thermal insulation performance of a material to be tested, which is implemented by the above-mentioned thermal insulation performance testing equipment.

[0025] The method comprises: attaching the material to be tested to the inner surface of the accommodating cavity of the test box to form a surface layer, and loading the heating material therein; measuring the first temperature of the surface of the heating material through the opening of the test box by a first temperature measuring element, and measuring the second temperature of the outer surface of the bottom wall by a second temperature measuring element, thereby obtaining a set of measurement temperature pairs; and characterizing the thermal insulation performance of the material to be tested by using the first temperature and the second temperature in the set of measurement temperature pairs.

[0026] Since the test box in the measuring device has a selectively constructed heat-insulating sleeve, after the material to be tested is coated on the inner surface of the test box, the loaded heat-generating material can only transfer heat through the top opening and the bottom wall. Therefore, the required measurement temperature can be easily obtained through the non-contact first temperature measuring element and the second temperature measuring element without causing thermal damage to the two temperature measuring elements. At the same time, with the help of the temperature measuring device, a relatively higher temperature measurement repeatability can be achieved, and the heat insulation performance of the material to be tested can be measured by the heat-generating material in different states.

[0027] According to some examples of the present application, using the first temperature and the second temperature in a set of measured temperature pairs to characterize the thermal insulation performance of the material to be tested is: using the thickness of the surface layer, the production and the first temperature and the second temperature in a set of measured temperature pairs to characterize the thermal insulation performance of the material to be tested; or, using the difference between the first temperature and the second temperature in a set of measured temperature pairs to characterize the thermal insulation performance of the material to be tested.

[0028] Optionally, characterizing the thermal insulation performance of the material to be tested by the difference between the first temperature and the second temperature in a set of measured temperature pairs includes: measuring the temperature multiple times at set time intervals within a given time range, thereby obtaining multiple sets of measured temperature pairs; using the difference between the first temperature and the second temperature in each set of measured temperature pairs as the vertical coordinate and the measured time as the horizontal coordinate, and drawing a curve in a two-dimensional coordinate system in which the above-mentioned difference changes with time.

[0029] According to some examples of the present application, the thermal insulation performance is characterized by thermal conductivity, and the thermal conductivity is calculated according to Formula 1;

[0030]

[0031] Wherein, λ represents thermal conductivity, M represents the mass of the bottom wall of the test box; c represents the specific heat capacity of the bottom wall of the test box; d- represents the thickness of the surface layer; F represents the surface area of ​​the bottom wall of the test box; t represents the time that the bottom wall of the test box is in contact with the heat-generating material; T M represents the temperature of the heating material; T0 represents the initial temperature of the bottom wall of the test box; T K Indicates the temperature of the bottom wall of the test box after it contacts the heating material; where T M Obtained by the first temperature, T0, T K Obtained by a second temperature.

[0032] Optionally, using the first temperature and the second temperature in a set of measured temperature pairs to characterize the thermal insulation performance of the material to be measured includes: measuring the temperature multiple times at set time intervals within a given time range to obtain multiple sets of measured temperature pairs; and processing the multiple sets of measured temperature pairs according to Formula 1 to obtain thermal conductivity.

[0033] According to some examples of the present application, the method includes: when multiple measurements are performed on the same material to be tested and the heat-generating material, after the previous measurement is completed, the test box is taken out, and when the first temperature stabilizes at the use temperature of the material to be tested, the next measurement is performed.

[0034] According to some examples of the present application, the method includes: before attaching the material to be tested to the inner surface of the accommodating cavity of the test box, allowing the test box to reach a first selected temperature; and / or, after attaching the material to be tested to the inner surface of the accommodating cavity of the test box and before loading the heat-generating material therein, allowing the test box and the release coating to reach a second selected temperature.

[0035] According to some examples of the present application, the material to be tested is a release agent, the heat-generating material is molten metal, the surface layer is a release agent coating, and the method includes: after the molten metal solidifies to form a metal part, determining whether the metal part can be freely taken out; optionally, when the metal part cannot be taken out, dismantling the test box and observing whether welding occurs on the bottom wall of the test box. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a schematic diagram of the structure of a test device for the thermal insulation performance of a conventional thermal insulation material;

[0038] Figure 2 A schematic diagram showing the testing principle of the thermal insulation performance of the thermal insulation material in the present application is shown;

[0039] Figure 3 A schematic diagram of the structure of the thermal insulation performance testing device provided in an embodiment of the present application from a first perspective;

[0040] Figure 4 A schematic diagram of the structure of the thermal insulation performance testing device provided in an embodiment of the present application at a second viewing angle;

[0041] Figure 5 Shows Figure 3 The structural intent of the matching relationship between the base, the fixing sleeve, the thermal insulation sleeve and the test box in the thermal insulation performance test equipment;

[0042] Figure 6 To show Figure 5 Schematic diagram of the cross-sectional structure of the device.

[0043] Icons: 1-crucible; 2-molten metal; 3-thermocouple; 4-thermocouple; 5-metal sample; 6-release agent layer; 100-thermal insulation performance test equipment; 10-frame; 101-roller; 102-platform; 201-test box; 2011-opening; 2012-accommodating chamber; 202-insulating sleeve; 203-first temperature measuring element; 204-second temperature measuring element; 205-base; 2051-partition; 2052-stud; 2053-lifting plate; 2054-cover; 2056-groove; 206-fixing sleeve; 30-electric cabinet; 301-temperature measuring bracket; 401-third bolt; 402-second bolt; 403-first flange; 404-second flange; 405-third flange. DETAILED DESCRIPTION

[0044] Release agents are often used in casting, for example. During the casting process, high-temperature molding materials are usually used. Therefore, the release agent needs to be able to withstand high temperatures and be heat-insulating (to prevent other equipment from being damaged by heat), while also being easy to remove the molded parts.

[0045] In order to measure the thermal insulation effect of the release agent, one can choose to measure its thermal conductivity and characterize its thermal insulation effect accordingly.

[0046] In practice, the inventors adopted Figure 1 The apparatus shown performs the above measurements.

[0047] The device comprises a crucible 1 , a thermocouple 3 and a thermocouple 4 .

[0048] The crucible 1 contains molten metal 2 .

[0049] The thermocouple 3 is inserted into the metal sample 5, and the surfaces of the metal sample 5 and the thermocouple 3 are brushed with a release agent to form a release agent layer 6. Then, the metal sample 5 and the thermocouple 3 brushed with the release agent are put into the crucible 1 together, and immersed in the molten metal liquid 2 (not in contact with the bottom wall or side wall of the crucible 1), and the part of the thermocouple 3 located in the metal liquid 2 is wrapped with the release agent.

[0050] Then, a thermocouple 4 is inserted into the molten metal liquid 2 .

[0051] Thermocouple 3 measures the temperature at the center of metal sample 5 ; thermocouple 4 measures the temperature of molten metal 2 .

[0052] In the above-mentioned measurement system, the heat insulation effect of the coating (release agent layer 6) on the surface of the metal sample 5 is characterized by its thermal conductivity. That is, the heat insulation effect of the release agent layer 6 (preventing heat from transferring to the metal sample 5 inside through the release agent layer 6) can be measured by the thermal conductivity λ [W / (m·K)] of the release agent layer 6, and calculated by the following formula 1.

[0053]

[0054] In formula 1: M is the mass of the metal sample 5 (kg); c is the specific heat of the metal sample 5; d is the thickness of the release agent layer 6 (m); F is the surface area of ​​the metal sample 5 (m 2 ); t-the time the metal sample 5 stays in the metal liquid 2 (h); T M -Temperature of the metal liquid 2 (K); T0-initial temperature of the metal sample 5 (K); T K - The temperature of the metal sample 5 after being immersed in the molten metal 2 (K).

[0055] Although the above method can measure the heat insulation effect of the release agent to a certain extent, the inventors have found through practice that the above method still has certain problems.

[0056] 1. Poor operability. Molten metal will solidify quickly at room temperature. Therefore, the operable time window of the above scheme is small, making the operation difficult. Once the operation time is not properly controlled, the thermocouple is very easy to be damaged, resulting in poor reproducibility of the measurement results.

[0057] 2. Poor accuracy. The above solution only measures the average thermal conductivity of the release agent in the period before the molten metal solidifies, and cannot measure the thermal conductivity when the temperature is lower than the melting point of the metal sample being tested. In other words, the thermal conductivity of the release agent should not only consider the thermal conductivity above the melting point of the metal being tested, but also the thermal conductivity below the melting point of the metal being tested. However, this existing solution cannot meet the above requirements.

[0058] 3. High cost. The thermocouple 4 is directly inserted into the molten metal, so it is easy for the thermocouple 4 to be stained with the molten metal. After the molten metal solidifies, it will destroy the probe of the thermocouple 4, and the measurement cost is high.

[0059] 4. It is difficult to record the test process. The above experimental device is difficult to prepare and record the test time.

[0060] In view of the above-mentioned current situation, the inventor has proposed a device for measuring the thermal insulation performance of a release agent after research, and also proposed a method for measuring the thermal insulation performance based on the device.

[0061] It should be noted that, although the above-mentioned device and method are proposed by the inventor based on the research of release agents, this does not mean that the device and method of the present application are only applicable to release agents. The device and method of the present application are also applicable to other coatings, coatings, various thermal insulation materials, heat preservation materials, waterproof materials, etc. The present application does not specifically limit its specific application field.

[0062] In order to make it easier for those skilled in the art to understand the present application, the following briefly describes the thermal insulation test principle of the present application. Figure 2 .

[0063] Figure 2 In FIG. 1 , a cylindrical container is shown with a release agent coated on the inner surface, and a molten metal melt is contained therein. The sides of the container are heat-insulated, the bottom is heat-conductive, and the top is open. Therefore, the main heat transfer location is between the top and the bottom (i.e., heat insulation in the horizontal direction and heat conduction in the vertical direction). Such a structure reduces the heat loss from the lateral surroundings of the container and highlights the temperature difference between the molten metal and the bottom of the container.

[0064] exist Figure 2In the figure, T1 represents the temperature of the upper surface of the molten metal; T2 represents the temperature of the outer bottom surface of the container; T3 represents the temperature of the upper surface of the release agent (in direct contact with the lower surface of the molten metal); and T4 represents the temperature of the lower surface of the release agent (in direct contact with the inner bottom wall of the container).

[0065] Therefore, the thermal insulation effect of the release agent can be characterized by the temperature difference between the release agent on the upper and lower sides of the metal melt. That is, the thermal insulation effect ΔT = T3-T4. However, since T3 and T4 are difficult to measure, T1 and T2 are used to replace T3 and T4 respectively, so the approximate expression of the thermal insulation effect is ΔT = T1-T2. In addition, according to this principle, the thermal conductivity of the release agent can be directly calculated to achieve a more accurate and specific characterization of the release agent.

[0066] See also Figures 3 to 6 In the example, the thermal insulation performance testing device 100 includes a frame 10, a thermal insulation sleeve 202, a test box 201, a first temperature measuring element 203 and a second temperature measuring element 204. The test box 201 is fixed to the frame 10 through the thermal insulation sleeve 202, and the first temperature measuring element 203 and the second temperature measuring element 204 are also directly or indirectly connected to the frame 10 and are constructed as needed, and the temperature of the corresponding area of ​​the test box 201 is measured.

[0067] Among them, the test box 201 can be used as a consumable. Therefore, in different thermal insulation performance testing devices 100, the test box 201 can be used interchangeably. In other words, the test box 201 can be used as an independent component (component one); at the same time, other components in the thermal insulation performance testing device 100 except the test box 201 can also be used as relatively independent components (component two). Therefore, component one and component two can be made separately and can also be stored separately, so that the thermal insulation performance testing device 100 is used as an assembled device. The two are assembled into one when in use.

[0068] Corresponding to the above measurement principle, the heat-insulating sleeve 202 and the test box 201 together constitute an example of the above cylinder, and the two temperature measuring elements are used to measure and obtain T1 and T2 based on the above structure.

[0069] The frame 10 can be constructed as a whole by welding or bolting using materials such as angle steel. Alternatively, it can also be made of various suitable materials such as wood or plastic steel. The present application does not make any special restrictions on its specific structure and manufacturing materials.

[0070] In the example of the present application, the rack 10 is constructed in a frame structure and mainly has two parts, one of which is used to place various detection and measurement equipment, and the other is used to place optional control equipment, power supply and other components (such as the electric cabinet 30 mentioned later). In addition, according to the installation and fixing requirements of various components in the equipment, the rack 10 can be configured with reinforcing ribs, ear plates, through holes, threaded holes, etc., which are not described one by one here.

[0071] Based on the need for convenient movement, in the example, a moving mechanism is provided on the frame 10, such as a roller 101 (which can be a universal wheel, fixed by bolts). The roller 101 can also be equipped with a locking structure (not shown) to keep it fixed at the desired position. In order to facilitate the installation of other components, in the example, the frame 10 has a platform portion 102 with a roughly "L"-shaped cross section, such as Figure 3 and Figure 4 The platform portion 102 is composed of angle steel and a skin (such as a steel plate) fixed thereon by welding or riveting.

[0072] Other components attached to / connected directly or indirectly to the rack 10 are clarified by the following description.

[0073] See also Figure 6 , the insulation sleeve 202 is hollow. For example, a hollow cylinder is formed by removing part of the material along the axis formed by the line connecting the centers of the upper and lower bases of the cylinder. Or, in short, the insulation sleeve 202 has a tubular structure. Of course, the insulation sleeve 202 can also be constructed with other structures, and this application does not make specific limitations. The insulation sleeve 202 can usually be made of a material with low thermal conductivity (such as less than 0.2W / (m·k)) or insulation. For example, the insulation sleeve 202 is an insulation brick, an insulation ceramic brick, etc.

[0074] There are different options for the arrangement and position of the heat insulating sleeve 202 on the rack 10. Due to the change or large fluctuation of the temperature measurement position, inconsistent or inaccurate temperature measurement may occur. Therefore, it is desired that the position of the heat insulating sleeve 202 is fixed so that the position of the test box 201 can be restricted accordingly.

[0075] As an implementation, the heat insulation sleeve 202 can be directly placed on the platform portion 102 of the frame 10. Alternatively, the heat insulation sleeve 202 can also be fixed to the platform portion 102 by other components (such as welding or detachable connection). For example, the thermal insulation performance testing device 100 has a fixing sleeve 206 or can also be called a jacket. The fixing sleeve 206 can be fixed to the aforementioned platform portion 102 by welding, riveting or bolting.

[0076] The fixing sleeve 206 has a roughly cylindrical structure. The heat-insulating sleeve 202 can cooperate with the fixing sleeve 206 in an interference fit manner, so that the heat-insulating sleeve 202 is limited, and the test box 201 is also fixed. Alternatively, in order to facilitate the subsequent replacement and removal of the heat-insulating sleeve 202, the heat-insulating sleeve 202 is embedded in the fixing sleeve 206 in a manner that it can be freely removed. In such an example, the fixing sleeve 206 can be provided with a stop portion (not marked) for restraining the heat-insulating sleeve 202, and the fixing sleeve 206 exposes the outer surface of the bottom wall of the test box 201. For example, the fixing sleeve 206 is a cylinder with a partial opening at the bottom, and therefore, the cross-sectional figure formed along its symmetry plane has a roughly L-shaped structure, see Figure 6 .

[0077] Furthermore, if Figure 4 As shown, the thermal insulation performance test device 100 can also be provided with a base 205 matched with a fixing sleeve 206. The base 205 is connected to the frame 10. The base 205 can be detachably connected to the platform portion 102 of the frame 10 by bolts, or can be made of a strong magnetic material and adsorbed on the frame 10, or fixed to the frame 10 by welding. In addition, the base 205 can be matched with the fixing sleeve 206 (such as detachably connected) so as to limit the thermal insulation sleeve 202 and the test box 201 together.

[0078] See also Figure 5 In the example of the present application, the fixing sleeve 206 is provided with an annular first flange 403 on its outer surface (which may be the middle part in the axial direction), and the first flange 403 has a through hole or a screw hole. Correspondingly, the base 205 has two flanges, one of which is a second flange 404 provided with a screw hole or a through hole, so as to be connected with the first flange 403 of the fixing sleeve 206 through a second bolt 402 or a light rod with a screw head. At the same time, the other flange of the base 205 is a third flange 405 connected with the platform part 102 of the frame 10 through a third bolt 401.

[0079] In addition, by modifying the structure of the base 205, it is also possible to facilitate the placement of the second temperature measuring element 204 so as to measure the temperature from the outer surface of the bottom wall of the test box 201. Figure 6 The cover plate 2054 is shown, through which the second temperature measuring element 204 is pressed against the outer surface of the bottom wall of the test box 201 .

[0080] In other examples, the second temperature measuring element 204 may also be directly held against the outer surface of the bottom wall of the test box 201 through the cover plate 2054. For example, the cover plate 2054 is matched with the outer surface of the bottom wall of the thermal insulation sleeve 202 in a surface contact manner, and is connected to the thermal insulation sleeve 202; at the same time, the cover plate 2054 is also connected to the rack 10. In such an example, the device for measuring the thermal insulation performance of the thermal insulation material may not be configured with the fixing sleeve 206 and the base 205. That is, the cover plate 2054 is connected to the rack 10, and then the cover plate 2054 is used to connect to the thermal insulation sleeve 202, and the test box 201 is cooperatively embedded in the thermal insulation sleeve 202, so as to contact the second temperature measuring element 204 held.

[0081] As an improved solution, in the illustrated solution of the present application, the cover plate 2054 has a limiting structure, and the limiting structure is located on the cover plate 2054 and is on the side where the cover plate 2054 contacts the outer surface of the bottom wall.

[0082] Optionally, the limiting structure is a limiting structure capable of accommodating the second temperature measuring element 204. For example, the limiting structure is a groove 2056, that is, a structure that is recessed inward from the surface of the cover plate 2054 (or can also be a convex portion protruding outward, and a groove is provided on the convex portion), such as Figure 6 As shown. The groove 2056 may be a semicircular structure in cross section, or other structures. Specifically, the shape of the thermocouple probe is used as a standard, and the probe can be at least partially exposed so as to contact the outer surface of the bottom wall of the test box 201. Considering that the temperature in the central area of ​​the cover plate 2054 may more accurately reflect the temperature, the groove 2056 is constructed to extend along the surface parallel to the surface to the middle of the outer surface of the bottom wall, combined with Figure 4 and Figure 6 As shown. The middle part thereof varies according to the different shapes of the cover plate 2054, and is generally located at the position of the symmetric center. For example, when the cover plate 2054 is a round pancake structure with a circular cross section, the center is the center of the circle. When the cover plate 2054 is a square, the center refers to the intersection of its two diagonals.

[0083] In some other improved examples, a liftable cover plate 2054 is provided inside the base 205, such as Figure 6 The lifting cover plate 2054 is convenient for fixing and releasing the second temperature measuring element 204. The cover plate 2054 can be lifted and lowered independently, or can be driven by other lifting components to perform lifting and lowering actions.

[0084] In the illustrated structure of the present application, the base 205 is mainly composed of a base body and a lifting mechanism. The base body has an internal cavity, and the lifting mechanism is located in the internal cavity and cooperates with the base body. The lifting mechanism can approach or move away from the bottom wall of the test box 201 inside the base body, thereby driving the cover plate 2054 located on the lifting mechanism to approach or move away from the bottom wall, thereby making the second temperature measuring element 204 approach or move away from the bottom wall of the test box 201.

[0085] As a specific optional example, the lifting mechanism includes an integrally formed partition plate 2051 and a lifter, wherein the partition plate 2051 is arranged along the radial section of the base 205 and connected to the inner wall of the base body. Meanwhile, the partition plate 2051 has a threaded hole.

[0086] Correspondingly, the lifter has a lifting plate 2053 and a stud 2052 connected to each other, and the stud 2052 cooperates with the threaded hole of the partition 2051. In this way, the lifting can be performed by cooperating with the stud 2052 of the lifter and the threaded hole of the partition 2051, so that the lifting plate 2053 moves, thereby achieving the lifting action. In such an example, the lifting mechanism is a purely mechanical device; in other examples, the lifting mechanism can also be an electric device, for example, the lifting mechanism is a piston rod of a hydraulic cylinder or a cylinder. However, the aforementioned hydraulic cylinder usually needs to be configured with a hydraulic pump, etc., and therefore its structure is more complicated and its volume size is larger.

[0087] The test box 201 mainly comprises two parts, namely, the side wall and the bottom wall. The side wall and the bottom wall can be formed in one piece (the example solution of the present application) or designed as separate parts and then connected by appropriate connectors. In addition, the side wall and the bottom wall of the test box 201 together define a top opening 2011 and a bottom closed receiving cavity 2012 (see also Figure 5 and Figure 6 ). Therefore, the test box 201 is a cylinder in structure. Among them, the opening 2011 can be used for the first temperature measuring element 203 to perform temperature testing, and the outer surface of the bottom wall can be used for the second temperature measuring element 204 to perform temperature testing. Based on this, in the scheme in which the test box 201 cooperates with the insulation sleeve 202, the test box 201 is embedded in the insulation sleeve 202 with the side wall. The side wall of the test box 201 is in direct contact with the inner wall of the insulation sleeve 202, so that the heat conduction from the side wall direction of the test box 201 is limited by the insulation sleeve 202. At the same time, the insulation sleeve 202 also exposes the opening 2011 at the top of the test box 201. And the insulation sleeve 202 also exposes the outer surface of the bottom wall of the test box 201 (at least part of it); in the illustrated scheme of the present application, the bottom wall of the test box 201 passes through the insulation sleeve 202 (when there is a fixed sleeve 206, it also passes through the fixed sleeve 206).

[0088] In the example of the present application, a first temperature measuring element 203 and a second temperature measuring element 204 are configured according to the construction mode of the test box 201 and the mode of cooperation with other components. Among them, the first temperature measuring element 203 is a non-contact temperature measuring element. That is, the temperature is measured through the opening 2011 of the test box 201 by collecting the infrared rays emitted by the heating material therein through the opening 2011. The second temperature measuring element 204 is a contact temperature measuring element, which contacts the outer surface of the bottom wall of the test box 201 for temperature measurement. That is, the temperature is measured by heat transfer between the two.

[0089] Therefore, the non-contact first temperature measuring element 203 can be selected as an infrared sensor temperature sensor. The first temperature measuring element 203 can be directly fixedly connected to the rack 10, or can be selected to cooperate with the rack 10 in a detachable connection. For example, the thermal insulation performance testing device 100 is configured with a temperature measuring bracket 301 connected to the rack 10, and the non-contact first temperature measuring element 203 is fixed by the temperature measuring bracket 301, such as Figure 2 As shown. The temperature measuring bracket 301 can be a metal rod, which is connected to the rack 10 by welding, and a bayonet is provided. The infrared temperature sensor is connected to the bayonet and can be detached from the bayonet when necessary and needed. Alternatively, the rack 10 is provided with a magnetic component, and the infrared temperature sensor has a corresponding magnetic component. Thus, the rack 10 and the infrared temperature sensor can be connected magnetically. For the second temperature measuring element 204, as a contact temperature measuring device, it can be selected as a thermocouple, or other contact temperature measuring devices.

[0090] In addition, in order to improve the measurement efficiency, electronic components can be configured to collect, record and view the measurement conditions, measurement results, etc. For example, a display, a computer, a controller (such as a micro control unit, a programmable logic controller, an industrial control computer), etc. These devices can be integrated into an electric cabinet 30 and fixed to the rack 10.

[0091] With that said, the thermal insulation performance testing device 100 in the example of the present application is described in detail. In order to demonstrate its practical performance, one usage thereof is described below.

[0092] In this usage mode, the aforementioned device is used in a method for measuring the thermal insulation performance of a material to be tested.

[0093] In the example, first, the material to be tested is attached to the inner surface of the receiving cavity 2012 of the test box 201 to form a surface layer. Secondly, the heating material is loaded into the receiving cavity 2012 of the test box 201 having the surface layer. Then, the first temperature measuring element 203 measures the first temperature of the surface of the heating material through the opening 2011 of the test box; and at the same time, the second temperature measuring element 204 measures the second temperature of the outer surface of the bottom wall of the test box 201.

[0094] In any measurement process, the above scheme can simultaneously obtain the above-mentioned first temperature and second temperature, thereby obtaining a set of measured temperature pairs. Therefore, in a given measurement cycle (the measurement cycle is determined according to the heat-generating material. For example, when the heat-generating material is molten metal, the measurement cycle is the length of time from when the molten metal is placed in the test box 201 to when it solidifies or any selected time), at least one temperature measurement can be performed according to the time interval between two adjacent measurements, so that one or more sets of measured temperature pairs can be obtained. In other words, in the present application, "measured temperature pairs" refer to two temperatures obtained by the first temperature measuring element 203 and the second temperature measuring element 204 at the same time or at the same time.

[0095] Therefore, on the basis of obtaining the above-mentioned measured temperature pairs, it can be used to measure or calculate the thermal insulation performance of the material to be tested. For example, the difference between the two temperatures in the measured temperature pair is used to characterize the thermal insulation performance. When only one temperature measurement is performed in a measurement cycle, a set of measured temperature pairs can be obtained, and therefore, the difference between the two is used as a numerical value characterizing the thermal insulation performance. When multiple temperature measurements are performed in a measurement cycle, multiple sets of measured temperature pairs can be obtained. Since the difference between the two temperatures in multiple measured temperature pairs can be obtained at this time, multiple differences are obtained. Therefore, a two-dimensional coordinate system curve can be drawn based on the multiple differences (vertical coordinates) and the temperature measurement time (horizontal coordinates), thereby obtaining a curve of the difference changing with the test time.

[0096] Alternatively, in some other examples, in order to examine the effect of the thickness of the surface layer on the thermal insulation performance, the thickness of the surface layer (or its production time, such as spraying time) and the two temperatures in the measured temperature pair can be combined to characterize the thermal insulation performance of the material to be tested. For example, a three-dimensional coordinate system curve is drawn with the thickness of the surface layer, the temperature measurement time and the difference as parameters.

[0097] In the above method of measuring the performance of thermal insulation materials, the difference between two temperature pairs in the measured temperature pair is mainly used as the basis. However, in order to more accurately (avoid interference from other factors) reflect the thermal insulation performance, the thermal conductivity can also be calculated based on the above equipment using the following formula 2 to characterize its thermal insulation performance.

[0098]

[0099] Wherein, λ represents thermal conductivity, M represents the mass of the bottom wall of the test box 201; c represents the specific heat capacity of the bottom wall of the test box 201; d- represents the thickness of the surface layer; F represents the surface area of ​​the bottom wall of the test box 201; t represents the time that the bottom wall of the test box 201 is in contact with the heat-generating material; T M represents the temperature of the heating material; T0 represents the initial temperature of the bottom wall of the test box 201; T KIt indicates the temperature of the bottom wall of the test box 201 after it contacts the heat-generating material.

[0100] In the above formula 2, M, c, d, and F are all equipment parameters / structural parameters of the thermal insulation performance measurement equipment. Therefore, they are generally fixed after the equipment is selected. M , T0, T k are parameters obtained according to the progress of measurement in the measurement cycle. And, T M The first temperature is obtained, and T0, T K The second temperature is obtained, and t can be obtained in real time by a timer. Alternatively, for an example that only focuses on the first and last two temperature measurements in a measurement cycle, t time can also be a pre-designed parameter, and T M , T0, T K It is obtained by two temperature measuring elements during the first and last temperature measurements mentioned above.

[0101] In order to avoid interference, error, environmental factors, etc., for the same type of release coating and heating material, multiple measurements can be selected. That is, after one measurement cycle is completed, the next measurement cycle is measured. Multiple measurement cycles can be implemented according to the requirements of data accuracy.

[0102] Furthermore, when multiple measurements (multiple measurement cycles) are performed on the same material to be tested and the heat-generating material, the test box 201 is taken out after the previous measurement is completed, and the next measurement is performed when the first temperature (the temperature measured at this time may be the temperature of the cover plate 2054 used to hold the second temperature measurement year) stabilizes at the operating temperature of the material to be tested.

[0103] Alternatively, when multiple measurement cycles are required, and each time the material to be tested and the heat-generating material are replaced, before the material to be tested is attached to the inner surface of the accommodating cavity 2012 of the test box 201 to form a surface layer, the test box 201 may be heated to the first selected temperature. Therefore, in the preparation stage of each measurement cycle, by heating the test box 201 to the first selected temperature, the temperature difference of the test box 201, which leads to the difference in the release coating on its surface (which may affect the results of subsequent measurements), can be avoided.

[0104] Further, based on similar reasons as above, after the material to be tested is attached to the inner surface of the accommodating cavity 2012 of the test box 201 and before the heat-generating material is loaded therein, the test box 201 and the surface layer are made to reach the second selected temperature. As an example, the temperature of the test box 201 and the surface layer reaching the second selected temperature means that the temperatures of the two are substantially consistent or the same.

[0105] Since no heating material is loaded into the test box 201 having the surface layer, the first temperature measuring element 203 measures the temperature of the surface layer on the inner surface of the bottom wall of the test box 201, while the second temperature measuring element 204 measures the temperature of the outer surface of the bottom wall of the test box 201. When the difference between the two temperatures is, for example, less than 10 degrees Celsius, it can be considered that the temperature of the release agent layer of the test box 201 reaches the second selected temperature. After that, the heating material can be loaded and measured.

[0106] In addition, considering the difference between the thermal insulation performance of the thermal insulation material under high temperature conditions and the thermal insulation performance of the thermal insulation material under low temperature conditions and the use temperature of the thermal insulation material, cooling (such as air cooling) can be performed after the above adjustment to the second selected temperature, so that the temperature measured by the first temperature measuring element 203 reaches 200 degrees Celsius before the heating material is loaded and the measurement is performed. This can ensure that the accuracy of the measurement results will not be affected by the gradual increase in heat storage of the device during the formal measurement. And this is more important for ensuring the accuracy and consistency of the calculated thermal conductivity when performing multiple measurements.

[0107] Through the above-mentioned manner, the influence of the test box 201 and the material to be tested itself can be avoided to a certain extent, thereby ensuring that the measurement conditions of each measurement cycle are relatively consistent for the same heating material and the material to be tested.

[0108] In a specific application example, the material to be tested as an object that reflects the thermal insulation performance can be a release agent, and the object that provides heat can be selected as molten metal. In addition, since the release agent must also take into account the demoulding performance, after measuring and calculating its thermal conductivity, the demoulding performance can be studied.

[0109] In this example, the measurement cycle starts from placing the molten metal in the test box 201 until the molten metal solidifies. Therefore, the measurement method for this example also includes testing to determine whether the metal piece can be freely taken out after the molten metal solidifies to form a metal piece. For example, the test box 201 is taken out of the insulation sleeve 202, and the test box 201 is poured to observe whether the metal piece can be taken out by itself under the action of gravity.

[0110] Alternatively, when the test box 201 is not fixed and limited, the metal piece can be directly pulled to see whether it can be taken out. If the metal piece cannot be taken out, the test box 201 can be dismantled to see whether the bottom wall of the test box 201 is welded. In this way, through this experiment, it can also be determined whether a welding reaction occurs between the release agent and the molten metal.

[0111] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A thermal insulation performance testing device, used in conjunction with a test box, wherein the test box has a receiving cavity with an opening defined by a side wall and a bottom wall, characterized in that: Thermal insulation performance testing equipment includes: frame; A hollow heat-insulating sleeve is placed on the frame, wherein the heat-insulating sleeve is configured to allow the test box to be embedded through the side wall and to expose the outer surface of the opening and the bottom wall; A non-contact first temperature measuring element, connected to the frame, for measuring the temperature through the opening; a second temperature measuring element connected to the frame and pressed by the bottom wall of the test box to measure the temperature from the outer surface of the bottom wall; The thermal insulation performance testing device comprises a cover plate, the second temperature measuring element is pressed onto the outer surface of the bottom wall through the cover plate so that the second temperature measuring element contacts the outer surface, the cover plate is provided with a limiting structure, the limiting structure is located at the contact side of the cover plate with the outer surface of the bottom wall, and the limiting structure is used to accommodate the limiting structure of the second temperature measuring element; the limiting structure is a groove, and the groove extends to the middle of the outer surface of the bottom wall; The thermal insulation performance testing device comprises a fixing sleeve connected to the frame, the fixing sleeve comprises a stopper for constraining the thermal insulation sleeve, and the fixing sleeve exposes the outer surface of the bottom wall of the test box through the stopper.

2. The thermal insulation performance testing equipment according to claim 1, characterized in that: The first temperature measuring element is an infrared sensor temperature sensor; And / or, the second temperature measuring element is a thermocouple.

3. The thermal insulation performance testing equipment according to claim 2, characterized in that: The thermal insulation performance testing equipment has a temperature measuring bracket connected to the frame, and the first temperature measuring element is fixed by the temperature measuring bracket.

4. The thermal insulation performance testing device according to any one of claims 1 to 3, characterized in that: The heat insulation sleeve is embedded in the fixing sleeve, thereby limiting the position of the test box.

5. The thermal insulation performance testing equipment according to claim 4, characterized in that: The thermal insulation performance testing equipment has a base, which is connected to the frame and the fixed sleeve. A cover plate for crimping the second temperature measuring element is arranged on the base, and the cover plate is constructed to crimp the second temperature measuring element to the outer surface of the bottom wall.

6. The thermal insulation performance testing equipment according to claim 5, characterized in that: The cover plate is liftably arranged on the base.

7. The thermal insulation performance testing equipment according to claim 6, characterized in that: The base comprises: a base body and a lifting mechanism, wherein the base body has an internal cavity, the lifting mechanism cooperates with the base body and is located in the internal cavity, and the lifting mechanism is used to drive the cover plate to approach or move away from the bottom wall.

8. The thermal insulation performance testing equipment according to claim 7, characterized in that: The lifting mechanism comprises a partition and a lifter, wherein the partition is connected to the inner wall of the seat body and has a threaded hole, and the lifter comprises a lifting plate and a stud connected to each other, and the stud cooperates with the threaded hole.

9. A method for measuring the thermal insulation performance of a material to be tested, implemented by the thermal insulation performance testing device according to any one of claims 1 to 8, characterized in that: The method comprises: Adhere the material to be tested to the inner surface of the containing cavity of the test box to form a surface layer, and fill the heating material therein; The first temperature measuring element measures a first temperature of the surface of the heat generating material through the opening of the test box, and the second temperature measuring element measures a second temperature of the outer surface of the bottom wall, thereby obtaining a set of measured temperature pairs; The thermal insulation performance of the material to be tested is characterized by the thickness of the surface layer, the preparation time, and the first temperature and the second temperature in the set of measured temperature pairs; or, the thermal insulation performance of the material to be tested is characterized by the difference between the first temperature and the second temperature in the set of measured temperature pairs.

10. The method for measuring the thermal insulation performance of a material to be tested according to claim 9, characterized in that: Characterizing the thermal insulation performance of the material to be measured by the difference between the first temperature and the second temperature in the set of measured temperature pairs includes: Within a given time range, the temperature is measured multiple times at set time intervals, thereby obtaining multiple groups of measured temperature pairs; With the difference between the first temperature and the second temperature in each set of measured temperature pairs as the ordinate and the measured time as the abscissa, a curve in a two-dimensional coordinate system showing the difference changing with time is drawn.

11. The method for measuring the thermal insulation performance of a material to be tested according to claim 9, characterized in that: The thermal insulation performance is characterized by thermal conductivity, and the thermal conductivity is calculated according to Formula 1; , formula 1; Wherein, λ represents thermal conductivity, M represents the mass of the bottom wall of the test box; c represents the specific heat capacity of the bottom wall of the test box; d represents the thickness of the surface layer; F represents the surface area of ​​the bottom wall of the test box; t represents the time that the bottom wall of the test box is in contact with the heat-generating material; T M represents the temperature of the heating material; T0 represents the initial temperature of the bottom wall of the test box; T K Indicates the temperature of the bottom wall of the test box after contacting the heat-generating material; Among them, T M By obtaining the first temperature, T0, T K is obtained by said second temperature.

12. The method for measuring the thermal insulation performance of a material to be tested according to claim 11, characterized in that: Characterizing the thermal insulation performance of the material to be measured by using the first temperature and the second temperature in the set of measured temperature pairs includes: Within a given time range, the temperature is measured multiple times at set time intervals, thereby obtaining multiple groups of measured temperature pairs; The plurality of groups of measured temperature pairs are processed according to Formula 1 to obtain thermal conductivity.

13. The method for measuring the thermal insulation performance of a material to be tested according to claim 9, characterized in that: The method comprises: When multiple measurements are performed on the same material to be tested and the heat-generating material, the test box is taken out after the previous measurement is completed, and the next measurement is performed when the first temperature is stabilized at the use temperature of the material to be tested.

14. The method for measuring the thermal insulation performance of a material to be tested according to claim 9, characterized in that: The method comprises: Before attaching the material to be tested to the inner surface of the receiving cavity of the test box, allowing the test box to reach a first selected temperature; And / or, after the material to be tested is attached to the inner surface of the accommodating cavity of the test box and before the heat-generating material is loaded therein, the test box and the surface layer are allowed to reach a second selected temperature.

15. The method for measuring the thermal insulation performance of a material to be tested according to claim 9, characterized in that: The material to be tested is a release agent, the heat-generating material is molten metal, the surface layer is a release agent coating, and the method includes: after the molten metal solidifies to form a metal part, determining whether the metal part can be freely taken out.

16. The method for measuring the thermal insulation performance of a material to be tested according to claim 15, characterized in that: When the metal piece cannot be removed, the test box is dismantled to observe whether the bottom wall of the test box is welded.

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