Test device for measuring heat characteristics of test piece

Abstract

To provide a test device which can generate on a test piece, pressing force of any magnitude in a vacuum environment, and can generate pressing on the test piece at a uniform surface pressure for correctly measuring heat characteristics of the test piece.SOLUTION: A test device 1 is for measuring heat characteristics of a test piece 3 by pressing the test piece 3 to an object for acting a contact pressure to the test piece 3 when contact thermal resistance of the test piece 3 is varied by a contact pressure which occurs when the test piece 3 is pressed to the object, and the device comprises: multiple metal bellows 13a, 13b which extend and shrink by a pressure difference between inside and outside for pressing the test piece 3 to the object at a prescribed pressure; pressure adjustment units 15a, 15b for adjusting inner pressures of the metal bellows 13a, 13b; surface pressure sensors 17a, 17b for measuring a contact pressure; and a control unit 19 for controlling the pressure adjustment units 15a, 15b so that the contact pressure becomes the prescribed pressure on the basis of the information of the surface pressure sensors 17a, 17b.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a testing device that measures thermal characteristics of a test piece by pressing the test piece against an object in a vacuum environment formed in a vacuum container. [Background technology]

[0002] Conventionally, there are cases where a thermal insulation performance measuring device is used to evaluate the thermal insulation performance of a test specimen (insulation material, etc.). The thermal insulation performance measuring device is composed of a vacuum vessel that forms a vacuum environment, a high-temperature plate and a measuring vessel housed in the vacuum vessel. The high-temperature plate is a heat source for evaluating the thermal insulation performance, and the measuring vessel is filled with liquefied gas for measuring the amount of heat transfer.

[0003] In the insulation performance test, a test specimen is placed on a high-temperature plate installed in a vacuum chamber, and a measurement vessel containing liquefied gas is placed on top of the test specimen. By placing the high-temperature plate on the bottom of the test specimen and the measurement vessel on the top, the heat of the high-temperature plate is transferred to the measurement vessel via the test specimen, and this heat causes the liquefied gas in the measurement vessel to evaporate. By measuring the amount of this evaporation, the amount of heat passing through the test specimen is measured, and the insulation performance is evaluated.

[0004] A thermal contact resistance exists at the interface between the test piece and the measurement container, and this thermal contact resistance changes depending on the pressing force generated at the interface. Therefore, in order to accurately evaluate the insulation performance, it is necessary to reproduce the same contact thermal resistance as the environment in which the test specimen will actually be used (actual equipment), and to do so, it is necessary to generate a pressure at the above-mentioned interface that is equivalent to that in the actual equipment.

[0005] In view of this, for example, Non-Patent Document 1 discloses a method for generating pressure on a test body in a vacuum environment. The test apparatus described in Non-Patent Document 1 (hereinafter referred to as Apparatus A) is intended to evaluate the thermal insulation performance of thermal insulation materials at low temperatures. As shown in Fig. 2 of Non-Patent Document 1, the thermal insulation material to be measured (test specimen) is mounted on the top of a hot plate, and the hot plate is placed on a support beam. This support beam is suspended from the top of the apparatus by a tension rod. The top of the thermal insulation material to be measured is in contact with a concentric protective low-temperature liquefied gas storage tank (Guard vessel) and a measuring low-temperature liquefied gas storage tank (Measuring vessel, which corresponds to the measuring vessel described above), and the thermal insulation material is cooled to a predetermined temperature.

[0006] In the above-mentioned device A, a protective low-temperature liquefied gas tank (Guard vessel) is provided to surround the measuring low-temperature liquefied gas tank (Measuring vessel), so that there is substantially no heat conduction from the center of the insulation to the outer periphery. In this state, the amount of heat passing in the vertical direction can be measured by measuring the amount of evaporation of the liquefied gas in the measuring low-temperature liquefied gas tank (Measuring vessel). This allows the insulation performance of the insulation material at low temperatures to be evaluated.

[0007] In order to perform the above performance evaluation correctly, it is important that the entire bottom surface of the measuring vessel is in contact with the insulating material. In the device A, the support beam, the hot plate, and the insulation material to be measured can be adjusted in the vertical direction by adjusting the handle on the tension rod. In other words, by adjusting the handle, the insulation material to be measured can be pressed against the low-temperature liquefied gas tank for measurement (measuring vessel), and the insulation material can be brought into contact with the entire bottom surface of the low-temperature liquefied gas tank for measurement (measuring vessel).

[0008] Further, another method for generating a pressure on a test piece is disclosed in, for example, Patent Document 1. In the thermoelectric property evaluation device in Patent Document 1 (hereinafter referred to as Device B), a pressure is applied to the test specimen by a cylindrical member (contact pressure adjustment member) with a spring built in. By using Device B, the thermoelectric properties of the electrical resistivity, Seebeck coefficient, and thermal diffusivity of the test specimen can be evaluated in a state where the test specimen and the measurement probe are in contact with each other at an appropriate pressure by the contact pressure adjustment member. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2020-139834 A [Non-patent literature]

[0010] [Non-Patent Document 1] "Development of a Thermal Insulation Performance Testing Device for Liquid Hydrogen Storage Tanks", Shoji Kamiya (Kawasaki Heavy Industries), et al., June 23, 2000, Cryogenics, Vol. 35, No. 9 Summary of the Invention [Problem to be solved by the invention]

[0011] In the above-mentioned device A, pressure is applied to the test specimen by the tightening torque of several handles (and tension rods), but since the handles are operated manually, it is difficult to apply the desired amount of pressure. Also, since multiple handles are operated manually, it is difficult to make the tightening torque of each handle the same, and it is difficult to apply a uniform surface pressure over the entire surface of the test specimen.

[0012] In addition, in the above-mentioned device B, the elastic force of the spring is used to generate pressure on the test piece, but the magnitude of the pressure generated on the test piece depends on the elastic force of the spring, so the magnitude of the pressure cannot be adjusted arbitrarily. In addition, in the case of a large test piece on the order of several meters, a large number of contact pressure adjustment members are required to apply a uniform surface pressure over the entire surface of the test piece.

[0013] As described above, there was a problem that the surface pressure was easily varied when applying pressure to the test specimen with the device A and the device B. There was also a problem that it was difficult to arbitrarily change the magnitude of the pressure applied to the test specimen. In addition, it was not possible to confirm the distribution of pressure applied to the test specimen or pinpoint the magnitude of the pressure.

[0014] The present invention has been made to solve the above-mentioned problems, and has an object to provide a testing device that can generate a pressing force of any magnitude on a test piece in a vacuum environment, and can generate a pressing force with a uniform surface pressure on the test piece, thereby accurately measuring the thermal characteristics of the test piece. [Means for solving the problem]

[0015] (1) A test apparatus according to the present invention measures thermal characteristics of a test body by pressing the test body against an object in order to apply contact pressure to the test body in a vacuum environment formed in a vacuum container, in a case where the contact thermal resistance of the test body changes due to contact pressure generated between the test body and an object when the test body is pressed against the object, a plurality of metal bellows that expand and contract due to a pressure difference between inside and outside the bellows, thereby pressing the test body against the object at a predetermined pressure; a pressure adjusting device for adjusting the internal pressure of the metal bellows; a surface pressure sensor for measuring the contact pressure; and a control device that controls the pressure adjustment device based on information from the surface pressure sensor so that the contact pressure becomes a predetermined pressure.

[0016] (2) In the above (1), the test specimen is a heat insulating material, and the thermal property is the amount of heat transmitted in a vertical direction.

[0017] (3) Furthermore, in the above-mentioned (1) or (2), a vacuum exhaust system is provided for exhausting the gas in the metal bellows to create a vacuum, thereby preventing unintended pressure from being applied to the test specimen due to the expansion of the metal bellows when the inside of the vacuum vessel is changed from atmospheric pressure to a vacuum.

[0018] (4) In addition, in the above-mentioned (1) or (2), the surface pressure sensor is provided between the test piece and the object.

[0019] (5) In addition, in the above-mentioned (1) or (2), the surface pressure sensor is provided between the plurality of metal bellows and the test piece.

[0020] (6) Furthermore, in the device described in (5) above, the control device is characterized in that it further has a function of controlling the pressure control device so as to equalize the pressing forces of the multiple metal bellows based on information from surface pressure sensors provided on the multiple metal bellows. Effect of the Invention

[0021] In the present invention, a pressing force of any magnitude can be applied to a test piece, and the displacement difference in the surface pressure distribution due to the pressing force applied to the test piece can be reduced, thereby enabling accurate measurement of the thermal characteristics of the test piece. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is an explanatory diagram of a test device according to an embodiment. [Diagram 2] FIG. 11 is an explanatory diagram of another aspect of the test device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The test apparatus of the present invention is used for testing a test object whose contact thermal resistance changes when pressed against an object, and can measure the thermal properties of the test object while the test object is pressed against the object. As an example of the test apparatus, in the present embodiment, a test apparatus that measures the amount of heat passing through as the thermal property of the test object to evaluate the thermal insulation performance will be described below. A testing device 1 according to this embodiment is shown in Fig. 1. In Fig. 1, the thick lines connecting each component indicate piping for supplying gas to a metal bellows 13 (described later) or for discharging gas from the metal bellows 13. Also, thin lines with "[" indicate an electrical system connecting each component.

[0024] The test equipment 1 evaluates the insulation performance by measuring the amount of heat passing through a test specimen 3, which is an insulating material, and as shown in FIG. 1, includes a vacuum vessel 5, a measurement vessel 7, a protective vessel 9, a high-heat plate 11, a metal bellows 13, a pressure adjusting device 15, a surface pressure sensor 17, a control device 19, and a vacuum exhaust facility 21. Each component will be described in detail below.

[0025] <Vacuum container> The vacuum vessel 5 is a vessel for forming a vacuum environment. The inside of the vacuum vessel 5 contains a measurement vessel 7, a protective vessel 9, a high-heat plate 11, a metal bellows 13, and a surface pressure sensor 17. The measurement of the amount of heat passing by the test device 1 is performed in the low-temperature vacuum environment formed by the vacuum vessel 5.

[0026] <Measurement container> Measurement container 7 is a cylindrical container filled with liquefied gas 23 (e.g., liquid nitrogen) for measuring the amount of heat passing through test specimen 3, and is placed with the bottom surface of measurement container 7 abutting against the center of the upper surface of test specimen 3. A high-heat plate 11 is placed on the lower surface side of test specimen 3, and as heat from this high-heat plate 11 is transferred to the bottom surface of measurement container 7 via test specimen 3, part of the liquefied gas 23 in measurement container 7 vaporizes.

[0027] The vaporized gas produced by vaporizing the liquefied gas 23 is extracted from a pipe 25 provided at the top of the measurement container 7, and the amount of the vaporized gas is measured by a flow meter (not shown). From the amount of the vaporized gas, the amount of heat added to the liquefied gas 23 is calculated, and the heat insulating performance of the test piece 3 (specifically, the heat insulating performance of the test piece 3 cooled to near the boiling point of the liquefied gas 23) is evaluated.

[0028] <Protective container> The protective container 9 is a container having a ring-shaped portion formed so as to surround the outer periphery of the measurement container 7, and is filled with the same liquefied gas 23 as the measurement container 7. The bottom surface of the protective container 9 is disposed so as to form the same plane as the bottom surface of the measurement container 7, and abuts against the upper surface of the test piece 3. The measurement container 7 and protective container 9 described above correspond to the object of the present invention.

[0029] By providing the protective container 9 filled with the liquefied gas 23 on the outer periphery of the measurement container 7, external heat input other than that to the bottom surface of the measurement container 7 is blocked, and the temperature gradient from the center to the outside in the measurement container 7 can be minimized. Therefore, the apparent heat transfer from the center of the measurement container 7 to the outside or in the opposite direction can be ignored. As a result, the heat input to the liquefied gas 23 in the measurement container 7 can be treated as heat that moves vertically through the test piece 3 from the high heat plate 11 to the bottom of the measurement container 7, i.e., the amount of heat passing in the vertical direction.

[0030] The type of liquefied gas 23 filled in the measurement container 7 and the protective container 9 may be appropriately selected depending on the temperature range to which the test specimen 3 is cooled. In addition to liquid nitrogen, liquefied hydrogen, liquefied helium, etc. may also be used.

[0031] <High temperature plate> The high-heat plate 11 is a plate-shaped member that generates a heat source for measuring the amount of heat passing through the test specimen 3. The high-heat plate 11 is arranged on the side of the test specimen 3 opposite to the side on which the measurement container 7 is arranged, i.e., on the underside of the test specimen 3, so as to abut against the test specimen 3. A thin plate-shaped electric heater is built into the high-heat plate 11, and the temperature of the high-heat plate 11 is controlled by this electric heater.

[0032] <Metal bellows> The metal bellows 13a and 13b have a bellows-shaped metal cylinder and expand and contract depending on the pressure difference between inside and outside. Although the metal bellows 13a and the metal bellows 13b are the same, for the purpose of distinction, the left side in the figure is designated as the metal bellows 13a and the right side is designated as the metal bellows 13b. When gas is supplied into the metal bellows 13a and 13b, the internal pressure of the metal bellows 13a and 13b increases, causing the metal bellows 13a and 13b to expand. When the metal bellows 13a and 13b expand, they press the test specimen 3, and the test specimen 3 is pressed against the bottom surfaces of the measurement container 7 and the protection container 9. By adjusting the amount of gas supplied to the metal bellows 13a and 13b, the internal pressure of the metal bellows 13a and 13b can be adjusted, and the force pressing the test specimen 3 can be adjusted.

[0033] 1 shows an example in which two metal bellows are used, but the number of metal bellows may be three or more. It is preferable to arrange the metal bellows so that a uniform surface pressure can be applied over the entire surface of the test piece 3, so that they may be arranged in line symmetry or point symmetry depending on the object to be measured.

[0034] As described above, the present invention is configured using a plurality of metal bellows. The reason for using a plurality of metal bellows is as follows. In typical commercially available circular metal bellows, when a force is applied in the axial direction of the bellows, the expansion and contraction width, and the reaction force are not uniform in the circumferential direction of the bellows. As a result, the directions of expansion and contraction of the metal bellows may not coincide with the axis of the bellows. The deviation in the expansion / contraction direction of a metal bellows is caused by variations in the flatness, plate thickness, material composition, etc. of the bellows during manufacture, and since they are general-purpose bellows, it is difficult to completely eliminate variations in the expansion width in the circumferential direction, contraction width, reaction force, etc. Furthermore, there are individual differences in this deviation in the expansion / contraction direction, and it is difficult to predict these differences.

[0035] If a test specimen is pressed with a single metal bellows, and the metal bellows stretches in a direction offset from the axis, the force pressing the test specimen will be biased, making it difficult to generate uniform contact pressure across the entire bottom surface of the measurement container. Therefore, in the present invention, multiple metal bellows are used. When the test specimen is pressed by multiple metal bellows, even if there is a misalignment in the expansion / contraction direction of each metal bellows, the pressing force is not biased to one place because there are multiple pressing fulcrums. Therefore, bias in the pressing force caused by the misalignment in the expansion / contraction direction of the metal bellows is mitigated, and it becomes possible to generate a uniform contact pressure over the entire bottom surface of the measurement container.

[0036] <Pressure Regulating Device> The pressure adjusting devices 15a and 15b are devices for adjusting the internal pressure of the metal bellows 13a and 13b. The pressure regulator 15a includes an inert gas supply facility 27a, a pressure regulator valve 29a, a pressure reducer valve 31a, and a fine pressure regulator 33a. The pressure regulator 15b also has a similar configuration to the pressure regulator 15a. In addition, the reference numerals of the pressure adjusting devices 15a, 15b and their respective components are given with the letter a those related to the pressure adjustment of the metal bellows 13a, and with the letter b those related to the pressure adjustment of the metal bellows 13b. A method for adjusting the internal pressure of the metal bellows 13a using the pressure adjusting device 15a will be described below.

[0037] The inert gas supplying equipment 27a is composed of a gas cylinder filled with an inert gas. By opening a pressure adjusting valve 29a provided between the inert gas supplying equipment 27a and the metal bellows 13a, an inert gas is supplied from the inert gas supplying equipment 27a to the metal bellows 13a. As the inert gas, it is preferable to use, for example, nitrogen gas, argon gas, or the like. The opening degree of the pressure adjustment valve 29a can be controlled by the control device 19, and the amount of gas supplied to the metal bellows 13a can be adjusted by adjusting the opening degree of the pressure adjustment valve 29a. When the inert gas is supplied to the metal bellows 13a, the internal pressure of the metal bellows 13a increases, and the metal bellows 13a expands.

[0038] Furthermore, by opening pressure reducing adjustment valve 31a, a portion of the inert gas in metal bellows 13a can be discharged, for example, to the atmosphere, and the internal pressure of metal bellows 13a can be reduced. The opening degree of pressure reducing adjustment valve 31a can be controlled by control device 19, and the amount of gas discharged from metal bellows 13a can be adjusted by adjusting the opening degree of pressure reducing adjustment valve 31a. By discharging a portion of the inert gas in metal bellows 13a, the internal pressure of metal bellows 13a decreases, and metal bellows 13a shrinks. The pressure regulation of the metal bellows 13a is performed in a state where the metal bellows 13a communicates with a micro-pressure regulation device 33a (described later) (with the on-off valve 35a open).

[0039] After the internal pressure of the metal bellows 13a has been adjusted to a certain degree by controlling the pressure increase adjusting valve 29a and the pressure reduction adjusting valve 31a, fine pressure adjustment is performed using the fine pressure adjusting device 33a as necessary. The fine pressure adjustment device 33a has a bellows-shaped metal cylinder and an adjustment handle 37 for expanding and contracting the bellows. When the adjustment handle is manually operated to contract the bellows, the inert gas in the fine pressure adjustment device is pushed out into the system, causing a small amount of inert gas to flow into the metal bellows 13a, and the internal pressure of the metal bellows 13a to rise slightly. When the adjustment handle 37 is manually operated to expand the bellows, the inert gas in the system flows into the fine pressure adjustment device, causing a small amount of inert gas to be discharged from the metal bellows 13a, and the internal pressure of the metal bellows 13a to fall slightly.

[0040] Pressure adjustment by the micro-pressure adjustment equipment 33a using the adjustment handle 37 makes it possible to adjust a micro-pressure range that is difficult to adjust only by opening and closing the pressurization adjustment valve 29a and the pressure reduction adjustment valve 31a. Note that the operation of the adjustment handle 37 is not limited to manual operation, and may be automatically controlled by the control device 19. The above describes a method for adjusting the internal pressure of metal bellows 13a using pressure adjusting device 15a, but the same applies to a method for adjusting the internal pressure of metal bellows 13b using pressure adjusting device 15b.

[0041] <Surface pressure sensor> The surface pressure sensors 17a and 17b are sheet-shaped sensors that measure the contact pressure generated when the test piece 3 is pressed against the measurement container 7 and the protection container 9 by the metal bellows 13a and 13b. During testing, the internal pressure of the metal bellows 13a, 13b is adjusted according to the measured values ​​of the surface pressure sensors 17a, 17b so that a predetermined contact pressure is generated between the bottom surface of the measurement container 7 and the test specimen 3. Since disposing the surface pressure sensors 17a, 17b between the bottom surface of the measurement container 7 and the test specimen 3 would impede heat transfer, in this embodiment, the surface pressure sensors 17a, 17b are provided between the bottom surface of the protection container 9, which forms the same plane as the bottom surface of the measurement container 7, and the test specimen 3 (see the x mark in FIG. 1).

[0042] Surface pressure sensor 17a is disposed at a position (above metal bellows 13a) where the contact pressure is likely to change due to pressure from metal bellows 13a. Similarly, surface pressure sensor 17b is disposed at a position (above metal bellows 13b) where the contact pressure is likely to change due to pressure from metal bellows 13b. The surface pressure sensors 17a and 17b are each electrically connected to the control device 19, so that the contact pressures measured by the surface pressure sensors 17a and 17b can be acquired by the control device 19 in real time.

[0043] <Control device> The control device 19 controls the pressure adjusting devices 15a and 15b based on the information from the above-mentioned surface pressure sensors 17a and 17b so that the contact pressure generated between the bottom surface of the measurement container 7 and the test piece 3 becomes a predetermined pressure. The control device 19 acquires the measured values ​​of the surface pressure sensors 17a and 17b in real time, and controls the pressure adjusting devices 15a and 15b so that these values ​​approach the predetermined pressure set for the test. In this way, the predetermined contact pressure can be generated between the bottom surface of the measurement container 7 and the test piece 3. In addition, since the internal pressures of the metal bellows 13a and 13b can be adjusted, the pressing forces of the metal bellows 13a and 13b can also be adjusted to be uniform, thereby generating a uniform pressing force over the entire surface of the test piece 3. The specific control method of the control device will be explained in more detail in the test method described later.

[0044] <Vacuum exhaust equipment> The vacuum exhaust system 21 is a system for exhausting gas from the metal bellows 13a and 13b to create a vacuum. When the vacuum exhaust valve 39a provided between the vacuum exhaust equipment 21 and the metal bellows 13a is opened and the vacuum exhaust equipment 21 is operated, the vacuum exhaust equipment 21 sucks in the gas (air) inside the metal bellows 13a, creating a vacuum inside the metal bellows 13a. Similarly, when the vacuum exhaust valve 39b provided between the vacuum exhaust equipment 21 and the metal bellows 13b is opened and the vacuum exhaust equipment 21 is operated, the vacuum exhaust equipment 21 sucks in the gas inside the metal bellows 13b, creating a vacuum inside the metal bellows 13b. The above-mentioned vacuum exhaust facility 21 is not an essential component of the present invention, but the reason for providing the vacuum exhaust facility 21 in this embodiment is as follows.

[0045] In the initial state of the test apparatus 1, air is present inside the vacuum vessel 5 and the metal bellows 13a, 13b, and the internal pressure is approximately atmospheric pressure. Therefore, before a test is performed, the air inside the vacuum vessel 5 is evacuated to create a vacuum inside the vacuum vessel 5. At this time, if the inside of the metal bellows 13a, 13b remains at atmospheric pressure, the metal bellows 13a, 13b will expand due to the pressure difference between the external pressure (vacuum) and the internal pressure (atmospheric pressure) of the metal bellows 13a, 13b, and unintended pressure may be applied to the test specimen 3.

[0046] Therefore, in this embodiment, a vacuum exhaust system 21 is provided to create a vacuum inside the metal bellows 13a, 13b. This allows the air inside the metal bellows 13a, 13b to be exhausted according to the exhaust state inside the vacuum vessel 5, and prevents unintended pressure from being applied to the test specimen 3. The vacuum exhaust facility 21 can also be used to adjust the pressure inside the metal bellows 13a and 13b together with the pressure adjusting devices 15a and 15b.

[0047] <Test Method> An example of a test method for evaluating the thermal insulation performance of the test specimen 3 using the test apparatus 1 configured as above will be described below. First, a test specimen 3 to be measured is set in the test apparatus 1 as shown in Fig. 1. At this time, the insides of the vacuum vessel 5 and the metal bellows 13a and 13b are at atmospheric pressure and room temperature. Next, the air in the vacuum vessel 5 is evacuated using a vacuum exhaust facility (not shown). At that time, it is preferable to suck the air in the metal bellows 13a and 13b by the vacuum exhaust facility 21 in accordance with the exhaust state in the vacuum vessel 5 so that unintended pressure is not generated on the test specimen 3.

[0048] After creating a vacuum inside the vacuum container 5, the measurement container 7 and the protective container 9 are filled with low-temperature liquefied gas 23 (such as liquid nitrogen) to cool the test piece 3 to a predetermined temperature. Then, the surface pressure sensors 17a and 17b installed between the protective container 9 and the test piece 3 are operated to start surface pressure measurement.

[0049] Next, the control device 19 starts to control the pressure adjusting devices 15a, 15b, and adjusts the internal pressure of the metal bellows 13a, 13b so that the measured values ​​of the surface pressure sensors 17a, 17b become predetermined pressures. Specifically, the pressurizing adjustment valves 29a, 29b are opened, and the inert gas is supplied from the inert gas supplying equipment 27a, 27b to the metal bellows 13a, 13b until the measured values ​​of the surface pressure sensors 17a, 17b reach the predetermined pressure. When the measured values ​​of the surface pressure sensors 17a, 17b exceed the predetermined pressure beyond the allowable range, the pressure reducing adjustment valves 31a, 31b are opened to reduce the internal pressure of the metal bellows 13a, 13b. After the pressure adjustment by the control device 19, the pressure is finely adjusted using the fine pressure adjustment equipment 33a, 33b so that the measured values ​​of the surface pressure sensors 17a, 17b approach the predetermined pressure even more. In addition, the gas inside the metal bellows 13a, 13b is sucked by the vacuum exhaust equipment 21 as necessary.

[0050] Furthermore, the control device 19 may compare the measured values ​​of the surface pressure sensors 17a and 17b, and if the difference between the two measured values ​​is large, control the pressure control devices 15a and 15b so as to reduce this difference. This allows a uniform pressure to be applied to the entire surface of the test piece 3, and allows the heat insulating performance of the test piece to be evaluated more accurately.

[0051] When the measured values ​​of the surface pressure sensors 17a, 17b reach a predetermined pressure (or when the difference from the predetermined pressure falls within an allowable range), the high heat plate 11 is heated to a predetermined temperature. The heat of the high heat plate 11 is transferred to the liquefied gas 23 in the measurement container 7 via the test piece 3, causing the liquefied gas 23 to vaporize. The amount of this vaporized gas is measured with a flow meter (not shown) to measure the amount of heat passing through the test piece 3.

[0052] After the measurement is completed, gas is introduced into the vacuum vessel 5 to change the inside of the vacuum vessel 5 from a vacuum state to a normal pressure state. At that time, in order to prevent the metal bellows 13a, 13b from being crushed by the increase in pressure inside the vacuum vessel 5, it is advisable to supply an appropriate amount of inert gas from the inert gas supply devices 27a, 27b to the metal bellows 13a, 13b.

[0053] As described above, the control device 19 obtains information from the surface pressure sensors 17a, 17b in real time and controls the pressure adjustment devices 15a, 15b based on this information, so that a predetermined contact pressure can be reliably generated between the measurement container 7 and the test specimen 3. Therefore, it is possible to reproduce a contact thermal resistance equivalent to the environment in which the test specimen 3 is actually used, and it is possible to accurately measure the amount of heat passing through the test specimen 3 and accurately evaluate the insulation performance.

[0054] In the above description, an example was shown in which the surface pressure sensors 17a and 17b were installed between the protective container 9 and the test piece 3, but the positions at which the surface pressure sensors 17a and 17b are installed are not limited to this. Another embodiment is shown in FIG. 2 shows an example in which surface pressure sensors 17a and 17b are provided between metal bellows 13a and 13b and test piece 3 (see the x marks in FIG. 2). Note that the external configuration of vacuum vessel 5 in FIG. 2 is the same as that in FIG. 1, and is therefore not shown.

[0055] When providing surface pressure sensors 17a, 17b between the metal bellows 13a, 13b and the test piece 3, it is preferable to arrange the surface pressure sensor 17a on the upper surface of the metal bellows 13a and the surface pressure sensor 17b on the upper surface of the metal bellows 13b, as shown in FIG. 2. Furthermore, the surface pressure sensors 17a, 17b do not necessarily need to be in contact with the test piece 3. When the high-heat plate 11 is placed between the metal bellows 13a, 13b and the test piece 3 as in this embodiment, it is preferable to provide the surface pressure sensors 17a, 17b between the high-heat plate 11 and the metal bellows 13a, 13b as shown in FIG. Even when the surface pressure sensors 17a, 17b are installed as shown in FIG. 2, the control device 19 controls the pressure control devices 15a, 15b so that the measured values ​​of the surface pressure sensors 17a, 17b become predetermined values.

[0056] 2, the pressure measured by surface pressure sensor 17a corresponds to the pressing force of metal bellows 13a, and the pressure measured by surface pressure sensor 17b corresponds to the pressing force of metal bellows 13b. Therefore, based on the information from surface pressure sensors 17a and 17b, control device 19 may control pressure control devices 15a and 15b so that the pressing forces of metal bellows 13a and 13b become equal. Specifically, the measured values ​​of surface pressure sensors 17a and 17b may be compared, and pressure control devices 15a and 15b may be controlled so that these values ​​become equal. By adjusting the pressing forces of the metal bellows 13a, 13b to be uniform, a uniform pressing force can be generated over the entire surface of the test specimen 3, and the heat insulating performance of the test specimen 3 can be evaluated accurately.

[0057] As described above, according to the testing device 1 of this embodiment, the control device 19 controls the pressure control devices 15a, 15b based on information from the surface pressure sensors 17a, 17b, thereby making it possible to generate a pressing force of any magnitude on the test piece 3. Furthermore, by providing a plurality of metal bellows 13a, 13b and adjusting the internal pressures thereof, it is possible to generate a uniform pressing force over the entire surface of the test piece 3 and further to maintain that state.

[0058] In the above-mentioned conventional device A, it was difficult to measure the amount of heat transmitted through the test specimen while applying a pressure of any magnitude uniformly over the entire surface of the specimen, but in the test device 1 of this embodiment, it is possible to measure the amount of heat transmitted while applying pressures up to about 150 kPa (G) in increments of 0.1 kPa (G). In addition, by changing the strength of the metal bellows 13a and 13b and the specifications of the valves and instruments, it is expected that even finer pressure adjustments and larger pressure applications will be possible.

[0059] In addition, by using the surface pressure sensors 17a and 17b as a means for measuring the contact pressure generated between the measuring device 1 and the test piece 3, it becomes possible to obtain the actual contact pressure generated in real time, enabling accurate pressure adjustment.

[0060] Another method for measuring contact pressure is to use a pressure measurement film that turns red when pressure is applied; however, there are pressure measurement films that turn red at 0.05 MPa (G) or more and pressure measurement films that turn red at 0.2 MPa (G) or more, so it is necessary to use different films depending on the pressure. Therefore, for each pressure measurement, the lid of the vacuum vessel 5 must be opened to break the vacuum and the pressure measurement film must be replaced. 3 In the case of a vacuum vessel of this scale, it takes about 1 hour from vacuum breaking to opening and closing the lid. Furthermore, if the vacuum is broken while low-temperature liquefied gas 23 is stored in the measurement vessel 7 and protective vessel 9, the vessels will frost, so it is necessary to discharge the liquefied gas 23 from the vessels to the outside of the system and return the inside of the vacuum vessel 5 to about room temperature before breaking the vacuum, which takes several days to about a week.

[0061] In addition, in the case of pressure measurement film, in order to specifically know the magnitude of pressure at a certain point, a special machine is required to analyze the magnitude of pressure from the shade of red.

[0062] In this regard, by using the surface pressure sensors 17a and 17b as in this embodiment, it is not necessary to replace the sensors for pressures up to several hundred kPa (G), and the magnitude of pressure at a specific location can be confirmed almost in real time, which is efficient.

[0063] Furthermore, by providing the fine pressure adjustment devices 33a and 33b, it becomes possible to adjust pressure in the fine pressure range, which is difficult to adjust by simply opening and closing the pressurization adjustment valves 29a and 29b and the pressure reduction adjustment valves 31a and 31b.

[0064] In addition, by providing a vacuum evacuation system 21 for creating a vacuum inside the metal bellows 13a, 13b, it is possible to prevent unintended pressure from being applied to the test specimen 3 due to the expansion of the metal bellows 13a, 13b when the pressure inside the vacuum container 5 is changed from atmospheric pressure to a vacuum.

[0065] Furthermore, the metallic bellows 13a, 13b reduce the risk of outgassing or contamination inside the vacuum vessel 5, making it possible to carry out tests stably in a vacuum environment.

[0066] In addition, in this embodiment, the test specimen 3 is pressed by a pressurization method using inert gas and metal bellows 13a, 13b. Since the pressing surface does not naturally drop as in the hydraulic method, the pressing method makes it possible to maintain the pressing force even if the specimen is left for a long period of time.

[0067] In addition, in this embodiment, an inert gas is used to pressurize the metal bellows 13a, 13b. Since the inert gas has a low risk of ignition, etc., the test can be performed safely even when the test specimen becomes hot.

[0068] In addition, in the present embodiment, the pressure adjusting devices 15a and 15b are provided for the metal bellows 13a and 13b, respectively, but the present invention is not limited to this. For example, one pressure adjusting device may be provided for multiple metal bellows, or multiple pressure adjusting devices may be provided for one metal bellows. However, it is preferable to provide a pressure regulator for each metal bellows as in the example of Fig. 1, since the internal pressure of the metal bellows can be adjusted individually, the pressing force of the multiple metal bellows can be made uniform. Note that it is also possible to configure the multiple pressure regulators to share one inert gas supply facility.

[0069] Furthermore, in the test apparatus 1 of this embodiment, a low-temperature insulating material is used as a test specimen, and the amount of heat passing therethrough in the vertical direction is measured as the thermal property thereof, but the test apparatus of the present invention is not limited to this. The testing apparatus of the present invention can also be applied to other testing apparatuses that measure the thermal characteristics of a test piece caused by changes in contact thermal contact resistance due to contact pressure when the test piece is pressed against an object and the test piece and the object are brought into contact at a predetermined surface pressure. [Explanation of symbols]

[0070] 1 Test equipment 3. Test specimen 5 Vacuum container 7. Measurement Container 9 Protective container 11 High temperature plate 13a, 13b Metal bellows 15a, 15b Pressure regulator 17a, 17b Surface pressure sensor 19 Control device 21 Vacuum exhaust equipment 23 Liquefied Gas 25 Piping 27a, 27b Inert gas supply equipment 29a, 29b Pressure adjusting valve 31a, 31b Pressure reducing valve 33a, 33b Fine pressure adjustment equipment 35a, 35b Opening and closing valve 37 Adjustment handle 39a, 39b Vacuum exhaust valve

Claims

1. 1. A test apparatus for measuring thermal characteristics of a test body by pressing the test body against an object in order to apply contact pressure to the test body, in a case where a contact thermal resistance of the test body changes due to contact pressure generated between the test body and an object when the test body is pressed against the object in a vacuum environment formed in a vacuum container, the test apparatus comprising: a plurality of metal bellows that expand and contract due to a pressure difference between inside and outside the bellows, thereby pressing the test body against the object at a predetermined pressure; a pressure adjusting device for adjusting the internal pressure of the metal bellows; a surface pressure sensor for measuring the contact pressure; a control device that controls the pressure adjusting device based on information from the surface pressure sensor so that the contact pressure becomes a predetermined pressure.

2. 2. The test apparatus according to claim 1, wherein the test specimen is a thermal insulating material, and the thermal characteristic is a quantity of heat transmitted in a vertical direction.

3. 3. The testing apparatus according to claim 1 or 2, further comprising a vacuum exhaust system for exhausting gas from within the metal bellows to create a vacuum, thereby preventing unintended pressure from being applied to the test specimen due to expansion of the metal bellows when creating a vacuum from atmospheric pressure within the vacuum vessel.

4. 3. The testing device according to claim 1, wherein the surface pressure sensor is provided between the test piece and the object.

5. 3. The testing device according to claim 1, wherein the surface pressure sensor is provided between the plurality of metal bellows and the test piece.

6. 6. The testing device according to claim 5, further comprising a function of controlling the pressure control device so that the pressing forces of the plurality of metal bellows are uniform based on information from surface pressure sensors provided on the plurality of metal bellows.

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