JP5827097B2 - Thermal conductivity measurement method - Google Patents

Description

  The present invention relates to a thermal conductivity measurement method, and more particularly to improvement in accuracy in measurement of thermal conductivity by a heat flow meter method.

  As a method for measuring the thermal conductivity of a test body such as a heat insulating material, there is a heat flow meter method (for example, Patent Document 1 and Patent Document 2). The heat flow meter method is simple and easy to use, so it is used not only for research institutions but also for many companies to check the performance of developed products and manage products.

  However, the measurement accuracy by the heat flow meter method depends on the calibration of the heat flow meter using a standard material. For this reason, in the heat flow meter method, it is necessary to appropriately calibrate the heat flow meter with a standard material.

  As this standard substance, for example, a glass wool board (thermal conductivity: 0.03 to .0... From the National Institute of Standards and Technology (NIST) in the United States for measuring the thermal conductivity of a heat insulating material. 05W / (m · K)), Pyrex® glass (thermal conductivity: 1 W / (m · K)) and pyroceram (thermal conductivity: 3-5 W / (m · K)) are provided .

  In general, when measuring the thermal conductivity of a specimen, a heat flow meter calibrated with a standard material having a thermal conductivity comparable to that of the specimen is used. For this reason, conventionally, for example, glass wool board has been used for measurement of a specimen having a thermal conductivity of about 0.03 to 0.05 W / (m · K), and Pyrex (registered trademark) glass and pyroceram have been used for thermal conductivity. It was used for measuring specimens with a rate around 1 W / (m · K) or more.

Japanese Patent Laid-Open No. 54-084780 Japanese Utility Model Publication No. 01-129651

  However, for example, glass wool board has a soft surface, whereas Pyrex (registered trademark) glass and pyroceram have hard surfaces, so when using the Pyrex (registered trademark) glass and pyroceram as standard materials, There was a problem that a gap consisting of an air layer was formed between the hard surface of the standard material and the hot plate.

  When an air layer is formed between the standard material and the hot plate, the thermal conductivity of the standard material is measured as a value smaller than the true thermal conductivity of the standard material. Further, when the pressure for pressing the standard substance against the hot plate is changed, the thickness of the air layer is changed, so that it is difficult to perform accurate calibration with the air layer formed. In addition, when the heat flow meter is calibrated with an air layer formed, if the same air layer as the air layer is not formed at the time of measurement of the test body using the heat flow meter, the heat flow of the test body is measured. It was difficult to accurately measure the conductivity.

  On the other hand, when the thermal conductivity of a test specimen having a thermal conductivity of 1 W / (m · K) or higher is measured using a heat flow meter calibrated with a glass wool board, for example, the thermal conductivity of the glass wool board and the Since the difference with the thermal conductivity of a test body is large, it was difficult to accurately measure the thermal conductivity of the test body.

  The present invention has been made in view of the above problems, and an object thereof is to provide a thermal conductivity measurement method with improved measurement accuracy.

  In order to solve the above problems, a thermal conductivity measurement method according to an embodiment of the present invention includes a test body between a heating plate and a cooling hot plate, and the outer peripheral surface of the test body is the outer peripheral surface of the heating plate. And arranged so as to be inside the outer peripheral surface of the cooling heat plate, cover the outer peripheral surface of the test body with a heat insulating material between the heating plate and the cooling heat plate, It is characterized by measuring thermal conductivity. According to the present invention, it is possible to provide a thermal conductivity measurement method with improved measurement accuracy.

  Moreover, in the said method, it is good also as using the heat flow meter calibrated with the standard substance whose heat conductivity is below that of the said test body. In the method, a thermal resistance layer having a thermal conductivity smaller than that of the test body is disposed between at least one of the test body and the heating plate and between the test body and the cooling heat plate. It is good to do.

  In the method, a temperature sensor may be disposed in direct contact with each of the first heat transfer surface on the heating plate side and the second heat transfer surface on the cooling heat plate side of the test body. . In this case, the temperature sensor is a differential thermocouple, the temperature difference between the first heat transfer surface and the second heat transfer surface of the test body is calculated based on the electromotive force of the differential thermocouple, and the temperature difference It is good also as measuring the thermal conductivity of the said test body based on.

  In the method, a thermal diffusion layer having a thermal conductivity larger than that of the test body is disposed between at least one of the test body and the heating plate and between the test body and the cooling heat plate. It is good to do. In this case, a heat absorption layer having an emissivity greater than that of the heat diffusion layer may be disposed on the specimen side of the heat diffusion layer.

  According to the present invention, it is possible to provide a thermal conductivity measurement method with improved measurement accuracy.

It is explanatory drawing which shows the cross section of an example of arrangement | positioning of the test body in the thermal conductivity measuring method which concerns on one Embodiment of this invention. It is explanatory drawing which shows the arrangement | positioning shown in FIG. 1 by planar view. It is explanatory drawing which shows the member which comprises the arrangement | positioning shown in FIG. It is explanatory drawing which shows the cross section of an example of the heat conductivity measuring apparatus used with the heat conductivity measuring method which concerns on one Embodiment of this invention. It is explanatory drawing which shows the cross section of the thermal conductivity measuring apparatus used with the conventional thermal conductivity measuring method. It is explanatory drawing which shows the cross section of the other example of arrangement | positioning of the test body in the thermal conductivity measuring method which concerns on one Embodiment of this invention. It is explanatory drawing which shows the cross section of the further another example of arrangement | positioning of the test body in the thermal conductivity measuring method which concerns on one Embodiment of this invention. It is explanatory drawing which shows the cross section of the further another example of arrangement | positioning of the test body in the thermal conductivity measuring method which concerns on one Embodiment of this invention. It is explanatory drawing which shows the cross section of an example of arrangement | positioning of the test body in the comparative example which concerns on one Embodiment of this invention. It is explanatory drawing which shows the cross section of the other example of arrangement | positioning of the test body in the comparative example which concerns on one Embodiment of this invention. It is explanatory drawing which shows an example of the result of having measured thermal conductivity in the Example which concerns on one Embodiment of this invention.

  Hereinafter, a thermal conductivity measurement method (hereinafter referred to as “the present method”) according to an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to this embodiment.

  FIG. 1 is an explanatory view showing a cross-section of an example of the arrangement of the test body 10 in the present method. FIG. 2 is an explanatory diagram showing the arrangement shown in FIG. 1 in plan view. That is, FIG. 1 shows a cross section of the arrangement taken along line II shown in FIG. FIG. 3 is an explanatory view showing members constituting the arrangement shown in FIG. 1 in perspective. FIG. 4 is an explanatory view showing a cross section of an example of the thermal conductivity measuring device 1 used in this method. FIG. 5 is an explanatory view showing a cross section of the thermal conductivity measuring device 100 used in the conventional thermal conductivity measuring method.

  This method is a method for measuring the thermal conductivity of the test body 10 by a heat flow meter method (HFM method). The heat flow meter method is defined in, for example, JIS A 1412-2. That is, JIS A 1412-2 defines a method for measuring the thermal conductivity in the steady state of a flat plate-like heat insulating material using a heat flow meter method.

  The heat flow meter method is a method for obtaining the thermal conductivity of the test body 10 by measuring the heat flow rate passing through the test body 10 with the heat flow meter 50. In the present invention, the heat flow meter method is defined by a comparative method using a standard plate (a plate-shaped test body made of a standard material) as a heat flow meter (for example, annex A of JIS A 1412-2). Plate comparison method).

  In the heat flow meter method, first, the heat flow meter 50 and the test body 10 are overlapped, a predetermined average temperature and a temperature difference are given by the heating plate 30 and the cooling heat plate 40, and a steady state is formed. That is, as shown in FIGS. 1 and 4, the test body 10 is disposed between the heating plate 30 and the cooling hot plate 40.

  Then, the heat transfer surface on the side of the heating plate 30 of the test body 10 (hereinafter referred to as “first heat transfer surface 12a”) is held at the first temperature by the heating plate 30 which is a high temperature side heater, and the low temperature side heater is used. The heat transfer surface on the cooling heat plate 40 side of the test body 10 (hereinafter referred to as “second heat transfer surface 12b”) is held at a second temperature lower than the first temperature by the cooling heat plate 40. By doing so, a temperature difference is formed between the first heat transfer surface 12a and the second heat transfer surface 12b.

  Next, the heat flow rate passing through the test body 10 is measured with the heat flow meter 50. That is, in the example shown in FIG.1 and FIG.4, the heat flowmeter 50 is arrange | positioned at the heating plate 30 side and the cooling hot plate 40 side of the test body 10, respectively. More specifically, in this example, the heat flow meter 50 on the first heat transfer surface 12a side is embedded in the heating plate 30, and the heat flow meter 50 on the second heat transfer surface 12b side is embedded in the cooling heat plate 40. Yes.

  And the heat flow rate which passes the test body 10 is measured with the heat flow meter 50 in the steady state in which the above-mentioned temperature difference was formed. In this example, the heat flow meter 50 also functions as a temperature sensor. That is, the temperature of the first heat transfer surface 12a and the temperature of the second heat transfer surface 12b of the test body 10 are measured by a temperature sensor (for example, a differential thermocouple) included in the heat flow meter 50.

  Further, in this example, in order to increase the measurement accuracy, the heat flow rate is measured by each of the heat flow meter 50 on the heating plate 30 side and the heat flow meter 50 on the cooling heat plate 40 side of the test body 10, and the average of the measured heat flow rate is measured. However, the present invention is not limited to this, and the heat flow meter 50 may be disposed on at least one of the test plate 10 on the heating plate 30 side and the cooling heat plate 40 side. However, even if the heat flow meter 50 is disposed only on one of the heating plate 30 side and the cooling heat plate 40 side of the test body 10, the temperature sensor is connected to the heating plate 30 side and the cooling heat of the test body 10. It arrange | positions at each of the board 40 side.

And using the result measured with the heat flow meter 50, the thermal conductivity of the test body 10 is calculated | required by following formula (I).

  In the formula (I), λ is the thermal conductivity of the test body 10, Q is the heat flow rate passing through the test body 10, and Δθ is the first heat transfer surface 12a and the second heat transfer surface 12b of the test body 10. , D is the thickness of the specimen 10 (for example, the distance between the first heat transfer surface 12a and the second heat transfer surface 12b), and S is the area through which the heat flow passes (for example, the first heat transfer surface 12b). If the area of the heat transfer surface 12a and the area of the second heat transfer surface 12b are the same, this area). In actual measurement, it is very difficult to accurately measure the heat flow rate Q and the temperature difference Δθ among the parameters on the right side of the formula (I).

  In this method, when using a standard plate having a known thermal conductivity, the standard plate having the same shape as that of the test body 10 is stacked on the test body 10 instead of the heat flow meter 50, and a predetermined average temperature and temperature difference are overlapped. And a steady state is formed, and the heat flow rate passing through the test body 10 is obtained by the standard plate.

That is, if it is assumed that the heat loss from the peripheral part of the test body 10 and the standard plate can be ignored, the thermal conductivity of the test body 10 can be obtained from the following formula (II).

In Formula (II), λ is the thermal conductivity (measured value) [W / (m · K)] of the test body 10, and λ _s is the thermal conductivity [W / (m · K)] of the standard plate. Yes, Δθ _s is the temperature difference [° C.] between the surface on the heating plate 30 side (high temperature side) of the standard plate and the surface on the cooling heat plate 40 side (low temperature side), and Δθ is the first difference of the specimen 10. The temperature difference [° C.] between the heat transfer surface 12 a and the second heat transfer surface 12 b, d _s is the thickness [m] of the standard plate, and d is the thickness [m] of the test body 10.

  Here, calibration of the heat flow meter 50 using a standard substance will be described. The heat flow meter 50 includes, for example, a substrate made of a thin plate material having stable thermal resistance, and a plurality of differential thermocouples (thermopiles) connected to one surface and the other surface of the substrate. Have. When a temperature difference is formed between one surface of the substrate and the other surface, an electromotive force is generated in the thermopile.

  In the calibration of the heat flow meter 50, the heat flow meter 50 is superimposed on a standard material (specifically, for example, a standard plate made of the standard material), and the heat transfer surface on one side of the standard material and the heat transfer surface on the other side. The relationship between the heat flow rate and the electromotive force when a predetermined temperature difference is formed between the heat transfer surface and the heat transfer surface is obtained.

That is, first, the heat flow in this case is expressed by the following formula (III).

In formula (III), Q _s is the heat flow rate through the standard material, λ _s is the thermal conductivity of the standard material, Δθ _s is the temperature difference formed in the standard material, and d _s is the standard material. And S _s is the area through which the heat flow passes (for example, the area of the heat transfer surface of the standard material). Here, since the thermal conductivity λ _s is a function of temperature, changing the measurement temperature changes the thermal conductivity λ _s , and as a result, the heat flow rate Q _s passing through the standard material also changes.

Therefore, by measuring the electromotive force of the thermopile at each measurement temperature while changing the measurement temperature, the relationship represented by the following formula (IV) is obtained.

In the formula (IV), V _s is an electromotive force generated by the heat flow meter 50, and f (V _s , θ) is a function of the electromotive force V _s and the temperature θ. That is, to calibrate the heat flow meter 50 is to determine this function f (V _s , θ).

Whether or not the heat flow meter 50 has been properly calibrated depends on the range of the heat flow rate Q _s that the heat flow meter 50 has been calibrated. For example, according to the above formula (III), the heat flow rate Q _s during calibration of the heat flow meter 50 is proportional to the thermal conductivity λ _s of the standard material.

Therefore, as a standard, the ratio of the heat flow Q _s during calibration using the aforementioned glass wool board, the heat flow Q _s during calibration using a Pyrex (trademark) glass has a thermal conductivity of the glass wool board The ratio of the rate λ _s (0.035 W / (m · K)) to the thermal conductivity λ _s (1 W / (m · K)) of the Pyrex (registered trademark) glass. That is, the heat flow rate Q _s at the time of calibration using Pyrex (registered trademark) glass is about 30 times the heat flow rate Q _s at the time of calibration using glass wool board.

For this reason, for example, when measuring a thermal conductivity of about 1 W / (m · K) equivalent to Pyrex (registered trademark) using a heat flow meter 50 calibrated with glass wool board, calibration with the glass wool board is performed. using the coefficients a _s obtained in, it will be measuring the large heat flow rate of about 30 times the heat flow Q _s during calibration by the glass wool board, measurement error becomes very large.

  Therefore, conventionally, for example, it is not appropriate to measure the thermal conductivity equivalent to Pyrex® glass using a heat flow meter 50 calibrated with a standard material whose thermal conductivity is equivalent to that of glass wool board. It was technical common sense.

  However, on the other hand, when using a standard material having a flexible surface such as glass wool board, the standard material and the standard material having a hard surface such as Pyrex (registered trademark) glass are used. Since it is possible to effectively avoid the formation of an air layer that becomes an unnecessary thermal resistance between the heating plate 30 and / or the cooling hot plate 40, the heat flow meter 50 can be accurately calibrated. .

  Therefore, the inventor of the present invention uses a heat flow meter 50 calibrated with a glass wool board to accurately measure a thermal conductivity of about 1 W / (m · K) like Pyrex (registered trademark) glass. The present invention was completed by earnestly studying independently.

  The present method is based on such a study unique to the inventors, and the test body 10 is disposed between the heating plate 30 and the cooling heat plate 40, and the outer peripheral surface 11 of the test body 10 is disposed on the heating plate 30. It arrange | positions so that it may become inner side from the outer peripheral surface 31 and the outer peripheral surface 41 of the said cooling heat plate 40, and the said outer peripheral surface 11 of the said test body 10 is the heat insulating material 20 between the said heating plate 30 and the said cooling heat plate 40. It is a method of covering and measuring the thermal conductivity of the specimen 10 by a heat flow meter method.

  That is, in this method, first, the test body 10 having a size smaller than the heating plate 30 and the cooling hot plate 40 is used. More specifically, the area of the first heat transfer surface 12a and the area of the second heat transfer surface 12b of the test body 10 are the area of the heat transfer surface 31 on the test body 10 side of the heating plate 30 and the area of the cooling heat plate 40, respectively. It is smaller than the area of the heat transfer surface 41 on the test body 10 side.

  And while surrounding the outer peripheral surface 11 of such a test body 10 with the heat insulating material 20 over the perimeter, the said test body 10 and the said heat insulating material 20 are arrange | positioned between the heating plate 30 and the cooling heat plate 40. FIG. .

  At this time, since the test body 10 is smaller than the heating plate 30 and the cooling heat plate 40, the outer peripheral surface 11 is disposed inside the outer peripheral surface 31 of the heating plate 30 and the outer peripheral surface 41 of the cooling heat plate 40. That is, in the example shown in FIG. 2, the outer peripheral surface 11 of the test body 10 is disposed so as to be radially inward from the outer peripheral surface 31 of the heating plate 30 and the outer peripheral surface 41 of the cooling heat plate 40.

  In addition, when using the heating plate 30 including a main heating plate and a protective heating plate surrounding the main heating plate (for example, heat conduction by a protection hot plate type heat flow meter method defined in Annex B of JIS A 1412-2) In the case of measuring the rate), the test body 10 may be arranged so that the outer peripheral surface 11 is inside the outer peripheral surface of the protective heat plate, and the outer peripheral surface 11 is the main heat plate. It is good also as arrange | positioning so that it may become an inner side from an outer peripheral surface.

  In this method, the test body 10 and the heat insulating material 20 arranged along the outer peripheral surface 11 of the test body 10 are sandwiched between the heating plate 30 and the cooling heat plate 40. The thermal conductivity of the body 10 is measured. In this method, the temperature at which the thermal conductivity is measured is not particularly limited, and may be, for example, in the range of −10 to 600 ° C.

  More specifically, the temperature at which the thermal conductivity is measured may be, for example, within a range of −10 to 100 ° C. or may be within a range of −10 to 70 ° C. In this case, for example, appropriate calibration of the heat flow meter 50 using a standard material that is a fiber body such as a glass fiber board can be reliably performed.

  Moreover, the temperature which measures thermal conductivity is good also as being in the range of 100-600 degreeC, for example. As described above, the temperature at which the thermal conductivity is measured by this method is not limited to these examples. For example, the temperature of the test body 10 (for example, the test body 10 made of an inorganic material such as a carbon fiber heat insulating material). When the thickness is 100 mm, while maintaining the first heat transfer surface 12a of the test body 10 at 2000 ° C. and maintaining the second heat transfer surface 12b at a temperature of 400 ° C. or less, the heat of the test body 10 is maintained. It is good also as measuring conductivity.

  The test body 10 is not particularly limited as long as it is a measurement target in this method. The material which comprises the test body 10 will not be restrict | limited especially if heat conductivity can be measured, It can be set as arbitrary inorganic materials and / or organic materials.

  As an inorganic material, it can be set as 1 or more types selected from the group which consists of glass, ceramics, a metal, sand, earth, stone, and a brick, for example. As an organic material, it can be set as 1 or more types selected from the group which consists of synthetic resin, synthetic rubber, natural rubber, paper, and wood, for example.

  The shape of the test body 10 is not particularly limited as long as it can be disposed between the heating plate 30 and the cooling hot plate 40, and may be, for example, a plate shape. Moreover, in the example shown in FIGS. 1-4, although the shape of the 1st heat transfer surface 12a and the 2nd heat transfer surface 12b of the test body 10 is circular, it is not restricted to this, For example, an ellipse or a polygon Any shape may be used.

  The thermal conductivity of the test body 10 is not particularly limited. For example, the thermal conductivity at −10 to 100 ° C. or −10 to 70 ° C. may be 0.1 W / (m · K) or more. 0.25 W / (m · K) or more, 0.5 W / (m · K) or more, or 1.0 W / (m · K) or more. Good. The upper limit value of the thermal conductivity of the test body 10 is not particularly limited. For example, the thermal conductivity may be 100 W / (m · K) or less.

  In this method, it is good also as using the heat flow meter 50 calibrated with the reference material whose heat conductivity is 1/2 or less of that of the test body 10. That is, in this case, the thermal conductivity of the test body 10 measured at a predetermined temperature in this method is more than twice that of the standard material used for calibration of the heat flow meter 50. The thermal conductivity of the standard substance may be 1/5 or less of that of the test body 10, may be 1/10 or less, and may be 1/20 or less. The thermal conductivity of the standard material may be 1/1000 or more of that of the test body 10.

  The thermal conductivity of the standard substance is not particularly limited. For example, the thermal conductivity at −10 to 100 ° C. or −10 to 70 ° C. may be 1.0 W / (m · K) or less, It may be 0.5 W / (m · K) or less, may be 0.1 W / (m · K) or less, and may be 0.05 W / (m · K) or less. . The lower limit value of the thermal conductivity of the standard material is not particularly limited. For example, the thermal conductivity may be 0.001 W / (m · K) or more.

  In this method, the test specimen 10 having a relatively large thermal conductivity can be measured using the heat flow meter 50 calibrated with a standard material having a relatively small thermal conductivity.

  That is, in this method, for example, the thermal conductivity in the temperature range of −10 to 100 ° C. or −10 to 70 ° C. is 0.5 W / (m · K) or less, which is 2 minutes of that of the specimen 10. It is good also as measuring the thermal conductivity of the said test body 10 in the said temperature range using the heat flow meter 50 calibrated with the reference material which is 1 or less. Further, for example, the thermal conductivity in the above temperature range is 0.1 W / (m · K) or less, and it is 1/2 or less, 1/5 or 1/10 or less of that of the test body 10. It is good also as measuring the thermal conductivity of the said test body 10 in the said temperature range using the heat flow meter 50 calibrated with the reference material. Further, for example, the thermal conductivity in the above temperature range is 0.05 W / (m · K) or less, and it is 1/2 or less, 1/5 or less, 1/10 or less, or 20 of that of the specimen 10. The heat conductivity of the test body 10 may be measured in the temperature range using the heat flow meter 50 calibrated with a standard material that is less than or equal to one part.

  In this method, for example, a heat flow meter 50 calibrated with a standard material having a thermal conductivity of 0.5 W / (m · K) or less in a temperature range of −10 to 100 ° C. or −10 to 70 ° C. is used. In this temperature range, the thermal conductivity of the test body 10 that is 1.0 W / (m · K) or more may be measured. Further, for example, using a heat flow meter 50 calibrated with a standard material having a thermal conductivity of 0.1 W / (m · K) or less in the above temperature range, 0.2 W / (m · K) in the temperature range. As mentioned above, it is good also as measuring the thermal conductivity of the test body 10 which is 0.5 W / (m * K) or more or 1.0 W / (m * K) or more. Further, for example, using a heat flow meter 50 calibrated with a standard material having a thermal conductivity of 0.05 W / (m · K) or less in the above temperature range, 0.1 W / (m · K) in the temperature range. As mentioned above, it is good also as measuring the thermal conductivity of the test body 10 which is 0.25 W / (m * K) or more, 0.5 W / (m * K) or more, or 1.0 W / (m * K) or more. .

  The standard substance is not particularly limited as long as it can be used for calibration of the heat flow meter 50, and can be any inorganic material and / or organic material. That is, the standard substance may be a fibrous body, for example. The fiber body is a molded body composed of inorganic fibers and / or organic fibers.

  As the inorganic fiber, for example, one or more selected from the group consisting of alumina-silica fiber, alumina fiber, silica fiber, rock wool, glass fiber (for example, glass wool), basalt fiber, and metal fiber can be used. . As the organic fiber, for example, one or more selected from the group consisting of polyester fiber, nylon fiber, rayon fiber, wool, cotton, hemp and acetate fiber can be used.

  The standard substance may be a synthetic resin, for example. In this case, the standard substance may be a synthetic resin foam. As the synthetic resin foam, for example, one or more selected from the group consisting of urethane foam and polystyrene foam can be used.

  The reference material preferably has a flexible surface, such as glass wool board. That is, it is preferable that the standard material has a flexible surface that deforms and adheres according to the shape of the surface such as the heat transfer surface 31 of the heating plate 30 and the heat transfer surface 41 of the cooling heat plate 40.

  The heat insulating material 20 is not particularly limited as long as it has a heat insulating property capable of suppressing the inflow and outflow of heat through the outer peripheral surface 11 of the test body 10, and any heat insulating material whose thermal conductivity is smaller than that of the test body 10. Can be used.

  The material which comprises the heat insulating material 20 will not be restricted especially if the above-mentioned heat insulation property is exhibited, It can be set as arbitrary inorganic materials and / or organic materials. As the inorganic material, inorganic fibers can be preferably used. Examples of the inorganic fiber heat insulating material 20 include an alumina-silica heat insulating material, an alumina heat insulating material, a silica heat insulating material, a rock wool heat insulating material, a glass wool heat insulating material, a calcium silicate heat insulating material, and a metal fiber heat insulating material. One or more selected from the group can be used. As the heat insulating material 20 calibrated from inorganic materials other than inorganic fibers, for example, a metal heat insulating material configured by laminating metal foils can be used.

  As the organic material, a synthetic resin can be preferably used. In this case, as the heat insulating material 20, a synthetic resin foam can be preferably used. As the heat insulating material 20 which is a synthetic resin foam, for example, one or more selected from the group consisting of urethane foam heat insulating material, polystyrene foam heat insulating material and packing material (for example, air cap) can be used. Moreover, the organic fiber type heat insulating material 20 can also be used. Moreover, as the heat insulating material 20, for example, a nanocomposite heat insulating material (for example, a porous heat insulating material including metal oxide fine particles such as silica fine particles) or a vacuum heat insulating material can be used.

  The shape of the heat insulating material 20 is not particularly limited as long as the heat insulating material 20 can cover the outer peripheral surface 11 of the test body 10 between the heating plate 30 and the cooling hot plate 40, and is, for example, a plate shape or a sheet shape. Is preferred.

  Specifically, the heat insulating material 20 may be configured by stacking a plurality of sheet-like heat insulating materials (for example, inorganic fiber-based sheet heat insulating materials) whose thickness is smaller than that of the test body 10. . In this case, the heat insulating material 20 having an appropriate thickness that matches the thickness of the test body 10 can be formed according to the number of sheet-like heat insulating materials to be stacked.

  Examples of the sheet-like heat insulating material 20 include a group consisting of inorganic fiber paper such as alumina-silica paper, foamed resin paper such as foam rubber sheet and urethane foam sheet, and organic fiber paper such as wood paper and paper. One or more selected from more can be used.

  The thermal conductivity of the heat insulating material 20 is not particularly limited as long as it is smaller than that of the test body 10, but may be, for example, 1/10 or less of the thermal conductivity of the test body 10. For example, the thermal conductivity of the heat insulating material 20 at −10 to 100 ° C. or −10 to 70 ° C. may be 0.2 W / (m · K) or less. The lower limit value of the thermal conductivity of the heat insulating material 20 is not particularly limited. For example, the thermal conductivity may be 0.001 W / (m · K) or more.

  The heat insulating material 20 is preferably arranged such that the distance between the inner peripheral surface 21 and the outer peripheral surface 11 of the test body 10 is 1 mm or less, and at least a part of the inner peripheral surface 21 is the outer periphery of the test body 10. More preferably, the inner peripheral surface 21 is disposed so as to be in contact with the surface 11, and the inner peripheral surface 21 is particularly preferably disposed so as to be in close contact with the outer peripheral surface 11 of the specimen 10.

  In the example shown in FIGS. 1 to 4, the outer peripheral surface 22 of the heat insulating material 20 is cooled in the heat transfer direction (the direction from the heating plate 30 toward the cooling heat plate 40) and the outer peripheral surface 31 of the heating plate 30. Although it arrange | positions so that it may overlap with the outer peripheral surface 41 of the hot platen 40, it is not restricted to this.

  That is, the position of the outer peripheral surface 22 of the heat insulating material 20 is not particularly limited as long as the heat insulating material 20 can suppress the inflow and outflow of heat through the outer peripheral surface 11 of the test body 10. It is good also as arrange | positioning so that it may become inside from the outer peripheral surface 31 and the outer peripheral surface 41 of the cooling heat plate 40, and the said outer peripheral surface 22 is outside the outer peripheral surface 31 of the heating plate 30, and the outer peripheral surface 41 of the cooling heat plate 40. It is good also as arrange | positioning.

  However, when the outer peripheral surface 22 of the heat insulating material 20 is outside the outer peripheral surface 31 of the heating plate 30 and the outer peripheral surface 41 of the cooling heat plate 40, the area where heat exchange with the outside air is performed increases. In addition, when the outer peripheral surface 22 is inside the outer peripheral surfaces 31 and 41, heat flows in and out between the heating plate 30 and the cooling heat plate 40 and the outside air, and measurement is performed in either case. The error is likely to increase. For this reason, as shown in FIGS. 1 to 4, the position of the outer peripheral surface 22 of the heat insulating material 20 coincides with the position of the outer peripheral surface 31 of the heating plate 30 and the outer peripheral surface 41 of the cooling heat plate 40 in the heat transfer direction. It is preferable.

  The thermal conductivity measuring apparatus 1 shown in FIG. 4 includes an arrangement of the test body 10 as shown in FIGS. 1 to 3 and further includes a heat insulating layer 60 surrounding the arrangement. The heat insulating layer 60 is provided to suppress heat inflow and outflow through the outer peripheral surface 31 of the heating plate 30 and the outer peripheral surface 41 of the cooling heat plate 40.

  In the example shown in FIG. 4, the heat insulating layer 60 is disposed so as to surround the outer peripheral surface 31 of the heating plate 30, the outer peripheral surface 22 of the heat insulating material 20, and the outer peripheral surface 41 of the cooling heat plate 40. In the example shown in FIG. 4, an air layer 61 is formed between the heat insulating layer 60 and the outer peripheral surface 31 of the heating plate 30, the outer peripheral surface 22 of the heat insulating material 20, and the outer peripheral surface 41 of the cooling heat plate 40. Yes.

  The material constituting the heat insulating layer 60 is not particularly limited as long as it suppresses the inflow and outflow of heat through the outer peripheral surface 31 of the heating plate 30 and the outer peripheral surface 41 of the cooling heat plate 40. For example, urethane foam, alumina silica type It is good also as being 1 or more types selected from the group which consists of a heat insulating material, a calcium silicate heat insulating material, rock wool, glass wool, and a polystyrene foam.

  According to this method, the inflow and outflow of heat via the outer peripheral surface 11 of the test body 10 can be effectively suppressed between the heating plate 30 and the cooling heat plate 40. For this reason, for example, even when the heat flow meter 50 calibrated with a standard material whose thermal conductivity is smaller than that of the test body 10 is used, the thermal conductivity of the test body 10 can be accurately measured.

  That is, in this method, the test body 10 having a size smaller than that of the heating plate 30 and the cooling heat plate 40 is used, and the outer peripheral surface 11 of the test body 10 is interposed between the heating plate 30 and the cooling heat plate 40. Covering with the heat insulating material 20 effectively suppresses the inflow and outflow of heat through the outer peripheral surface 11 of the test body 10 and calibrates the heat flow meter 50 with a standard material whose thermal conductivity is smaller than that of the test body 10. Realize an environment close to the time environment.

  Then, by using the heat flow meter 50 calibrated with a standard material having a small thermal conductivity in an environment close to the environment at the time of calibration, the thermal conductivity of the test body 10 larger than that of the standard material is accurately measured. be able to.

  Conventionally, as shown in FIG. 5, the size of the test body 110 is the same as the size of the heating plate 130 and the cooling hot plate 140. That is, the test body 110 was arranged such that the outer peripheral surface 111 thereof was positioned to coincide with the outer peripheral surface 131 of the heating plate 130 and the outer peripheral surface 141 of the cooling heat plate 140 in the heat transfer direction.

  In this regard, for example, in the above-mentioned JIS A 1412-2, the size of the test body 110 is set to a size that completely covers the heating plate 130, and the shape and dimensions of the test body 110 are the same as those of the heating plate 130. It is prescribed to match.

  Conventionally, since it has been common technical knowledge to calibrate the heat flow meter 150 with a standard material having a thermal conductivity equivalent to that of the test body 110, the heating plate 130 and the cooling hot plate 140 have the same shape and dimensions. This is because it is considered that the same environment as that at the time of calibration with the reference material can be formed by completely covering with the test body 110.

  In contrast, the inventor of the present invention calibrates the heat flow meter 50 with a standard material whose thermal conductivity is smaller than that of the test body 10 and uses the heat flow meter 50 in an environment close to the environment at the time of the calibration. Thus, the inventors have repeatedly studied based on the original technical idea of accurately measuring the thermal conductivity of the test body 10 which is larger than the thermal conductivity of the standard material, and have reached the present method as described above.

  Moreover, as shown in FIG. 5, the conventional thermal conductivity measuring apparatus 100 also has the heat insulation layer 160 similar to the heat insulation layer 60 shown in FIG. The heat insulating layer 160 was disposed without being in contact with the outer peripheral surface 111 of the test body 110. That is, an air layer 161 was formed between the heat insulating layer 160, the outer peripheral surface 131 of the heating plate 130, the outer peripheral surface 111 of the test body 110, and the outer peripheral surface 141 of the cooling heat plate 140. Specifically, the heat insulation layer 160 was arrange | positioned 1 mm or more apart from these outer peripheral surfaces 131,111,141, for example.

  FIG. 6A shows another example of the arrangement of the test body 10 in this method. That is, in this method, as shown in FIG. 6A, the thermal conductivity is at least between the test body 10 and the heating plate 30 and between the test body 10 and the cooling heat plate 40. It is good also as arrange | positioning the heat resistance layer 70 smaller than that. Specifically, in the example illustrated in FIG. 6A, the thermal resistance layer 70 is disposed between the test body 10 and the heating plate 30 and between the test body 10 and the cooling heat plate 40.

  The thermal conductivity of the thermal resistance layer 70 is not particularly limited as long as it is smaller than that of the test body 10. For example, the thermal resistance layer 70 may be 1/10 or less of that of the test body 10. It is good also as being.

  For example, the thermal conductivity of the thermal resistance layer 70 at −10 to 100 ° C. or −10 to 70 ° C. may be 0.05 W / (m · K) or less, and may be 0.1 W / (m · K) It may be the following. The lower limit value of the thermal conductivity of the thermal resistance layer 70 is not particularly limited. For example, the thermal conductivity may be 0.001 W / (m · K) or more.

  The material constituting the thermal resistance layer 70 is not particularly limited as long as the thermal resistance by the thermal resistance layer 70 is larger than that by the test body 10, and any inorganic material and / or organic material can be used.

  As the inorganic material and / or organic material, inorganic fiber and / or organic fiber can be preferably used. As the inorganic fiber, for example, one or more selected from the group consisting of alumina-silica fiber, alumina fiber, silica fiber, rock wool, glass fiber, and basalt fiber can be used. As the organic fiber, for example, one or more selected from the group consisting of polyester fiber, nylon fiber, rayon fiber, wool, cotton, hemp and acetate fiber can be used.

  Further, the organic material constituting the heat resistance layer 70 may be a synthetic resin such as rubber. In this case, as the heat resistance layer 70, a foam of a synthetic resin such as a foamed rubber sheet can be preferably used. The heat resistance layer 70 may be made of wood and / or paper.

  The thermal resistance layer 70 is preferably composed of a flexible sheet. That is, for example, when the heat resistance layer 70 is at least one selected from the group consisting of a sheet composed of inorganic fibers and / or organic fibers, a rubber sheet, and a foam sheet, the heat resistance layer 70 is It can be composed of a flexible sheet.

  By forming the heat resistance layer 70 from a flexible sheet, for example, a gap (air) is formed between the heat resistance layer 70 and the first heat transfer surface 12a and / or the second heat transfer surface 12b of the test body 10. Formation of a layer) can be effectively avoided.

  In this method, the heat flow rate that passes through the test body 10 can be effectively reduced by providing the thermal resistance layer 70. That is, by laminating the thermal resistance layer 70 on the test body 10, a virtual test including the test body 10 and the thermal resistance layer 70 and having a lower net thermal conductivity than that of the test body 10 alone. The body can be formed.

  For this reason, for example, even when the heat flow meter 50 calibrated with a standard material whose thermal conductivity is smaller than that of the test body 10 is used, the thermal conductivity of the test body 10 can be accurately measured.

  That is, in this method, by providing the thermal resistance layer 70, the heat flow rate passing through the test body 10 is effectively suppressed, and the heat conductivity of the heat flow meter 50 made of a standard material whose thermal conductivity is smaller than that of the test body 10. Realize an environment close to the calibration environment.

  Then, by using the heat flow meter 50 calibrated with a standard material having a small thermal conductivity in an environment close to the environment at the time of calibration, the thermal conductivity of the test body 10 larger than the standard material can be accurately measured. it can.

  In addition, when using a heat flow meter 50 calibrated with a standard material having a flexible surface whose thermal conductivity is smaller than that of the test body 10, the thermal resistance layer 70 composed of a flexible sheet is provided, It is also possible to realize an environment closer to the environment at the time of calibration of the heat flow meter 50 with the standard material.

  Moreover, this method is good also as arrange | positioning the temperature sensor 51 in direct contact with each of the 1st heat transfer surface 12a and the 2nd heat transfer surface 12b of the test body 10, as shown to FIG. 6A. That is, in this case, a temperature sensor 51 for measuring the temperature of the first heat transfer surface 12a of the test body 10 is disposed in direct contact with the first heat transfer surface 12a, and the temperature of the second heat transfer surface 12b is set. A temperature sensor 51 for measurement is arranged in direct contact with the second heat transfer surface 12b. The temperature sensor 51 is not particularly limited as long as it can measure the temperature. For example, the temperature sensor 51 may be a thermocouple.

  The method of disposing the temperature sensor 51 is not particularly limited. For example, the temperature sensor 51 is welded to the first heat transfer surface 12a and the second heat transfer surface 12b of the test body 10, or the temperature sensor is measured by an adhesive tape. A method of attaching 51 to the first heat transfer surface 12a and the second heat transfer surface 12b can be used.

  In the example shown in FIG. 6A, the temperature sensor 51 is disposed on each of the first heat transfer surface 12a and the second heat transfer surface 12b, and at the heating plate 30 side and the cooling heat plate 40 side of the test body 10, respectively. Although the heat flow meter 50 is arranged, the arrangement of the temperature sensor 51 is not limited to this. For example, the heat flow meter 50 that also functions as a temperature sensor is provided on each of the first heat transfer surface 12a and the second heat transfer surface 12b. It is good also as arranging to contact.

  By arranging the temperature sensor 51 in direct contact with each of the first heat transfer surface 12a and the second heat transfer surface 12b of the test body 10, the temperature of the first heat transfer surface 12a and the second heat transfer surface 12b are arranged. Can be measured accurately.

  That is, as described above, in measuring the thermal conductivity of the test body 10 based on the above formula (I), the temperature difference between the first heat transfer surface 12a and the second heat transfer surface 12b of the test body 10 is accurately determined. It is not easy to measure. In particular, when the thermal conductivity of the test body 10 is relatively large, the temperature difference between the first heat transfer surface 12a and the second heat transfer surface 12b is small, so it is difficult to accurately measure the temperature difference. .

  In this regard, according to the temperature sensor 51 that directly contacts each of the first heat transfer surface 12a and the second heat transfer surface 12b of the test body 10, a small temperature difference can be accurately measured.

  Furthermore, in this method, the temperature sensor 51 is a differential thermocouple, and the temperature difference between the first heat transfer surface 12a and the second heat transfer surface 12b of the test body 10 is calculated based on the electromotive force of the differential thermocouple. The thermal conductivity of the test body 10 may be measured based on the temperature difference.

  That is, in this case, the temperature sensor 51 is a differential thermocouple arranged in direct contact with each of the first heat transfer surface 12a and the second heat transfer surface 12b. The differential thermocouple is not particularly limited, and for example, a K type, T type, B type, R type, S type, N type, E type and / or J type can be used.

  Then, by measuring the electromotive force of the differential thermocouple generated in the steady state, and converting the measured electromotive force into temperature, the temperature difference between the first heat transfer surface 12a and the second heat transfer surface 12b is obtained. calculate.

  Thus, by converting from the electromotive force of the differential thermocouple, the temperature difference between the first heat transfer surface 12a and the second heat transfer surface 12b can be more accurately compared with the case where the temperature is calculated by measuring the temperature of the differential thermocouple. Can be requested.

  Further, when the heat resistance layer 70 is composed of a flexible sheet, by laminating the heat resistance layer 70 on the first heat transfer surface 12a and / or the second heat transfer surface 12b of the test body 10, Formation of a gap due to the unevenness of the temperature sensor 51 disposed on the first heat transfer surface 12a and the second heat transfer surface 12b can be effectively avoided.

  FIG. 6B shows still another example of the arrangement of the test body 10 in this method. That is, in this method, as shown in FIG. 6B, the thermal conductivity is at least one between the test body 10 and the heating plate 30 and between the test body 10 and the cooling heat plate 40. It is also possible to dispose a heat diffusion layer 80 larger than the above.

  Specifically, in the example illustrated in FIG. 6B, the thermal diffusion layer 80 is disposed between the test body 10 and the heating plate 30 and between the test body 10 and the cooling heat plate 40, and more specifically. Specifically, between one thermal resistance layer 70 and the test body 10 (more specifically, the test body 10 and the heat insulating material 20) and the other thermal resistance layer 70 and the test body 10 (more specifically, And the test body 10 and the heat insulating material 20). The heat resistance layer 70 may be disposed, for example, between the one heat resistance layer 70 and the heating plate 30 and between the other heat resistance layer 70 and the cooling heat plate 40. The arrangement shown in FIG. 6B is preferred.

  The thermal conductivity of the thermal diffusion layer 80 is not particularly limited as long as it is larger than the thermal conductivity of the test body 10, and may be, for example, 10 times or more of the thermal conductivity of the test body 10, or 100 times or more. It is good as well.

  Further, for example, the thermal conductivity of the thermal diffusion layer 80 at −10 to 100 ° C. or −10 to 70 ° C. may be 10 W / (m · K) or more, and 100 W / (m · K) or more. It may be there. The upper limit value of the thermal conductivity of the thermal diffusion layer 80 is not particularly limited. For example, the thermal conductivity may be 2000 W / (m · K) or less.

  The material constituting the thermal diffusion layer 80 is not particularly limited as long as the thermal conductivity of the thermal diffusion layer 80 is larger than that of the test body 10, and can be any inorganic material and / or organic material. . That is, the thermal diffusion layer 80 may be, for example, one or more selected from the group consisting of a metal sheet, a synthetic resin sheet, and a carbon fiber sheet.

  As a metal which comprises a metal sheet, a thing with high heat conductivity is preferable, for example, 1 or more types selected from the group which consists of aluminum, gold | metal | money, silver, copper, iron, platinum, stainless steel, and these alloys are used. be able to. As a synthetic resin sheet, what has adhesiveness is preferable, for example, 1 or more types selected from the group which consists of a polyimide film and a fluorine resin film can be used.

  By providing the thermal diffusion layer 80, heat conduction in the direction along the first heat transfer surface 12a and / or the second heat transfer surface 12b of the test body 10 is promoted, and the first heat transfer surface 12a in the direction is accelerated. The temperature and / or the temperature of the second heat transfer surface 12b can be made uniform.

  For this reason, for example, the position where the heat flow meter 50 and / or the temperature sensor 51 is disposed and / or the influence of heat exchange with the outside due to the presence of the heat flow meter 50 and / or the temperature sensor 51 is effectively reduced. be able to.

  FIG. 6C shows still another example of the arrangement of the test body 10 in this method. That is, in this method, as shown in FIG. 6C, a heat absorption layer 81 having an emissivity larger than that of the heat diffusion layer 80 may be disposed on the test body 10 side of the heat diffusion layer 80.

  Specifically, in the example shown in FIG. 6C, the heat absorption layer 81 is disposed on each of the test body 10 side of the one heat diffusion layer 80 and the test body 10 side of the other heat diffusion layer 80, and more Specifically, between one thermal diffusion layer 80 and the test body 10 (more specifically, the test body 10 and the heat insulating material 20) and the other thermal diffusion layer 80 and the test body 10 (more specifically, Are respectively disposed between the test body 10 and the heat insulating material 20).

  The emissivity of the heat absorption layer 81 is not particularly limited as long as it is larger than the emissivity of the heat diffusion layer 80, but it is preferably as close to 1.0, for example, 0.5 or more, and 0.8 or more. It is preferable that The material constituting the heat absorption layer 81 is not particularly limited as long as the emissivity of the heat absorption layer 81 is larger than that of the heat diffusion layer 80. That is, the heat absorption layer 81 may be a layer formed by applying a black paint on the surface of the thermal diffusion layer 80 on the side of the test body 10, for example.

  By providing the heat absorption layer 81, reflection of heat radiation by the heat diffusion layer 80 can be effectively suppressed.

  Next, specific examples according to the present embodiment will be described.

  Using a commercially available thermal conductivity measuring device (HC-110, manufactured by Eihiro Seiki Co., Ltd.), the thermal conductivity of the specimen 10 was measured by a heat flow meter method. This thermal conductivity measuring device was preferably used for measuring thermal conductivity at a temperature of −10 ° C. or higher.

  As a reference material, a glass fiber board (SRM 1450c) provided by NIST was used. This glass fiber board has a flexible surface that is in good contact with the surface of the heating plate 30 and the like, and has a low thermal conductivity so that the contact thermal resistance between the glass fiber board and the surface of the heating plate 30 and the like can be almost ignored. The graph fiber board was preferably used in a temperature range of 6 to 70 ° C. (approximately 0.035 W / (m · K) and a high porosity).

As the test body 10, Pyrex (registered trademark) glass (Pyrex (registered trademark) 7740) provided by NIST was used. This Pyrex (registered trademark) glass had a diameter of 50 mm, a thickness of 6.6 mm, a weight of 29.7 g, and a density of 2.2 × 10 ³ kg / m ³ .

  Each of the heating plate 30 and the cooling hot plate 40 was a disc-shaped heater having a diameter of 61 mm in which a heat flow meter 50 that also functions as a temperature sensor was embedded. And the heat conductivity of the test body 10 which consists of Pyrex (trademark) glass was measured using the heat flow meter 50 calibrated with the glass fiber board.

[Comparative Example 1]
As shown in FIG. 7A, between the heating plate 30 and the cooling hot plate 40, the test body 10 has the outer peripheral surface 11 of the test body 10 and the outer peripheral surface 31 of the heating plate 30 and the outer periphery of the cooling hot plate 40. It arrange | positioned so that it might become inside from the surface 41, and the thermal conductivity of the said test body 10 was measured, without covering the outer peripheral surface 11 of the said test body 10 with the heat insulating material 20 (for example, refer FIG. 6A).

  That is, as shown in FIG. 7A, nothing is arranged between the outer peripheral surface 11 of the test body 10 and the outer peripheral surfaces 31 and 41 of the heating plate 30 and the cooling hot plate 40, and a gap formed by the air layer 62 is formed. It had been.

[Comparative Example 2]
As shown in FIG. 7B, the following configuration was added to the arrangement of Comparative Example 1 described above (the arrangement shown in FIG. 7A), and the thermal conductivity of the test body 10 was measured. That is, the temperature sensor 51 is arranged in direct contact with each of the first heat transfer surface 12a and the second heat transfer surface 12b of the test body 10, and the heating plate 30 of the temperature sensor 51 on the first heat transfer surface 12a. A thermal resistance layer 70 made of ceramic paper, which is a kind of inorganic fiber paper, was laminated on each of the side and the cooling heat plate 40 side of the temperature sensor 51 on the second heat transfer surface 12b.

  As the temperature sensor 51, a commercially available differential thermocouple (K type) is used, and by converting from the electromotive force of the differential thermocouple, the first heat transfer surface 12a and the second heat transfer surface 12b of the test body 10 The temperature difference was calculated.

[Example 1]
As shown to FIG. 6A, the following structure was added to arrangement | positioning of the comparative example 2 mentioned above (arrangement shown to FIG. 7B), and the thermal conductivity of the test body 10 was measured. That is, the outer peripheral surface 11 of the test body 10 was covered with the heat insulating material 20 between the heating plate 30 and the cooling hot plate 40. The heat insulating material 20 was formed by laminating a plurality of ring-shaped ceramic papers.

[Example 2]
As shown in FIG. 6B, the following configuration was added to the arrangement of Example 1 described above (the arrangement shown in FIG. 6A), and the thermal conductivity of the test body 10 was measured. That is, the thermal diffusion layer 80 was disposed between one thermal resistance layer 70 and the test body 10 and between the other thermal resistance layer 70 and the test body 10. As the heat diffusion layer 80, a circular aluminum foil was used.

[Example 3]
As shown in FIG. 6C, the following configuration was added to the arrangement of Example 2 described above (the arrangement shown in FIG. 6B), and the thermal conductivity of the specimen 10 was measured. That is, the heat absorption layer 81 was formed on the surface of the thermal diffusion layer 80 on the side of the test body 10. The heat absorption layer 81 was formed by applying a black paint on the surface of the aluminum foil constituting the thermal diffusion layer 80 on the side of the test body 10.

[Measurement results of thermal conductivity]
FIG. 8 shows the result of measuring the thermal conductivity. In FIG. 8, the horizontal axis indicates the temperature θ (° C.) at which the thermal conductivity is measured, and the vertical axis indicates the measured thermal conductivity λ (W / (m · K)). In FIG. 8, the white triangle mark is Comparative Example 1, the white diamond mark is Comparative Example 2, the black square mark is Example 1, the black triangle is Example 2, and the black circle is the Example. 3 shows the values measured respectively, and the solid line is provided as the true thermal conductivity of the specimen 10 (Pyrex (registered trademark) 7740) from the manufacturer of the thermal conductivity measuring device used (Eihiro Seiki Co., Ltd.). The standard value is shown.

  As shown in FIG. 8, the thermal conductivity measured in Comparative Example 1 and Comparative Example 2 was significantly smaller than the standard value. That is, in Comparative Example 1 and Comparative Example 2, the thermal conductivity of the test body 10 could not be accurately measured.

  On the other hand, the thermal conductivity measured in Examples 1 to 3 was close to the standard value. That is, in Examples 1 to 3, by covering the outer peripheral surface 11 of the test body 10 with the heat insulating material 20 between the heating plate 30 and the cooling hot plate 40, the measurement accuracy is remarkable as compared with Comparative Examples 1 and 2. Improved. Further, in Example 2, a thermal conductivity within a range of 10% from the standard value is obtained, and in Example 3, a thermal conductivity within a range of 5% from the standard value is obtained. It was.

  Thus, between the heating plate 30 and the cooling heat plate 40, the test body 10 has the outer peripheral surface 11 of the test body 10 from the outer peripheral surface 31 of the heating plate 30 and the outer peripheral surface 41 of the cooling heat plate 40. The reference material used to calibrate the heat flow meter 50 by placing the outer peripheral surface 11 of the test body 10 with the heat insulating material 20 between the heating plate 30 and the cooling heat plate 40. The thermal conductivity of about 1 W / (m · K) corresponding to about 30 times the thermal conductivity of was able to be accurately measured.

  DESCRIPTION OF SYMBOLS 1 Thermal conductivity measuring apparatus, 10 test body, 11 outer peripheral surface of test body, 12a 1st heat transfer surface, 12b 2nd heat transfer surface, 20 heat insulating material, 21 inner peripheral surface of heat insulating material, 22 outer peripheral surface of heat insulating material 30 heating plate, 31 outer peripheral surface of the heating plate, 32 heat transfer surface of the heating plate, 40 cooling heat plate, 41 outer peripheral surface of the cooling heat plate, 42 heat transfer surface of the cooling heat plate, 50 heat flow meter, 60 heat insulation layer, 61 air layer, 62 air layer, 70 heat resistance layer, 80 heat diffusion layer, 81 heat absorption layer, 100 conventional thermal conductivity measuring device, 100 test body, 111 outer peripheral surface of test body, 130 heating plate, 131 heating plate Outer peripheral surface, 140 cooling hot plate, 141 outer peripheral surface of cooling hot plate, 150 heat flow meter, 160 heat insulation layer.

Claims (7)

Between the heating plate and the cooling heat plate, the test body is arranged so that the outer peripheral surface of the test body is inside the outer peripheral surface of the heating plate and the outer peripheral surface of the cooling heat plate,
Cover the outer peripheral surface of the test body with a heat insulating material between the heating plate and the cooling hot plate,
A thermal resistance layer (standard material) having a thermal conductivity less than or equal to half that of the test body between at least one of the test body and the heating plate and between the test body and the cooling hot plate. )
Using a heat flow meter calibrated with a standard material whose thermal conductivity is less than half that of the specimen,
A thermal conductivity measurement method, wherein the thermal conductivity of the specimen is measured by a heat flow meter method. The thermal conductivity measurement method according to claim 1 , wherein the thermal conductivity of the specimen is measured within a range of −10 ° C. to 600 ° C. The thermal conductivity at −10 ° C. to 100 ° C. or −10 ° C. to 70 ° C. of the test specimen is 0.1
It is W / (m * K) or more, The thermal conductivity measuring method of Claim 1 or 2 characterized by the above-mentioned. The temperature sensor is disposed in direct contact with each of the first heat transfer surface on the heating plate side and the second heat transfer surface on the cooling heat plate side of the test body. The thermal conductivity measuring method according to any one of the above. The temperature sensor is a differential thermocouple;
Calculate the temperature difference between the first heat transfer surface and the second heat transfer surface of the specimen based on the electromotive force of the differential thermocouple,
The thermal conductivity measurement method according to claim 4, wherein the thermal conductivity of the specimen is measured based on the temperature difference. A thermal diffusion layer having a thermal conductivity larger than that of the test body is disposed between at least one of the test body and the heating plate and between the test body and the cooling hot plate. Item 6. The thermal conductivity measurement method according to any one of Items 1 to 5. The heat conductivity measuring method according to claim 6, wherein a heat absorption layer having an emissivity larger than that of the heat diffusion layer is disposed on the specimen side of the heat diffusion layer.

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