JP7106073B2 - Thermal conductivity measuring device and thermal conductivity measuring method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermal conductivity measuring device and a thermal conductivity measuring method for measuring the thermal conductivity of a thermal insulating material or the like.

In Patent Document 1, a specimen is sandwiched between a hot plate having a main hot plate that heats the central portion of the specimen and a protective hot plate that surrounds the main hot plate, and a cooling plate. , the hot plate has a central high temperature side heater for heating the central portion of the test piece at a first temperature and a peripheral high temperature side heater for heating the peripheral portion of the test piece at a first temperature; The cooling plate has a low-temperature side heater that heats the test piece at a second temperature lower than the first temperature, and an outer circumference arranged to surround the outer circumference of the test piece, the hot plate, and the cooling plate A heater is provided, a first heat insulating material is disposed on the side of the hot plate opposite to the test body side, a second heat insulating material is disposed on the side opposite to the hot plate side of the first heat insulating material, and A thermal conductivity measurement device is disclosed having a compensating heater within the secondary insulation.

In Non-Patent Document 1, as a method for measuring the thermal resistance and thermal conductivity of a thermal insulating material, a flat plate sandwiched between two parallel plates having isothermal surfaces with different temperatures is described in the section "4 Principles" of JIS. A method is disclosed in which the temperature is controlled so that the inside of the test piece is in a steady state one-dimensional heat flow, and heat transfer characteristics such as thermal resistance and thermal conductivity are measured in the thickness direction of the test piece. In addition, in the section "5.2 Apparatus shape" of "5 Measuring apparatus" of JIS, there are two test piece method and one test piece method, and the hot plate (main hot plate and protective hot plate) of the measuring device ) and the shape of the cooling hot plate shall be a circle with a diameter of 0.2 m to 1 m or a square with a side of 0.2 m to 1 m, of which a circle with a diameter of 0.3 m or a square with a side of 0.3 m are defined as standard dimensions. In addition, the section "6.3 Dimensions and thickness" of "6 Test piece" of JIS stipulates that the test piece should be sized to completely cover the thermal plate. The heating means are provided at four locations: a cooling hot plate, a main hot plate, a protective hot plate, and a backflow preventing hot plate.

JP 2013-11563 A

Japanese Industrial Standards JIS A1412-1 Protective hot plate method (GHP method)

In recent years, as the development of electric vehicles accelerates, the issue of realizing comfort inside the vehicle while saving power has been pointed out. For this reason, it is important to evaluate the thermal insulation properties of the materials used in automobile parts, that is, the thermal conductivity of the materials. The JIS A 1412-1 (protected hot plate method) measuring device is a square with a side of 0.3 m, which is the standard size generally distributed in the market. Since it is stipulated that the size should be equal to or larger than the standard size, a square having a side of 0.3 m or longer is stipulated. For this reason, it is widely used as an evaluation method for heat insulating materials in the construction field, where building materials themselves are large in size. However, in the case of parts used in the development of automobile parts, there are cases where the test piece is a square with a side length of 0.1 m. For this reason, there was a problem that it was impossible to measure with measuring devices that were distributed.

Ignoring the JIS standard, which stipulates that the test piece must be of a size that completely covers the hot plate, a problem when a test piece smaller than the hot plate is used for measurement will be explained here. When a test piece smaller than the hot plate is used for measurement, the periphery of the test piece comes into contact with air that does not have the same thermal conductivity as the test piece, so the heat flow in the peripheral area deviates from the one-dimensional heat flow required for measurement. When this turbulent heat flow reaches the portion of the test piece that is in close contact with the main hot plate, it causes a measurement error and hinders accurate measurement. This phenomenon becomes more pronounced as the thickness of the test piece increases.

The invention of Patent Document 1 is based on the description in paragraph [0006] of Patent Document 1, "When the size of the specimen is small (when the area where heat flows is small), the test for the heat flow propagating in the thickness direction Because the influence of the heat flow (heat flow in the width direction) through the outer peripheral edge of the body increases, the measurement error increases." 2), a low-temperature side heater, a peripheral heater, and a compensating heater. There was a problem of having to control the temperature of five places such as the cooling plate and the main hot plate.

In addition, regarding the device according to Non-Patent Document 1, for example, in order to reduce the size of a standard size device having a square of 0.3 m on one side to 1/3 the size, a protective hot plate with a heater built in There was a problem that the manufacturing of the parts would be difficult because the parts such as the parts had to be reduced to 1/3.

In addition, in the apparatus of Non-Patent Document 1, heating means such as heaters had to be provided at four locations: the main hot plate, the protective hot plate, the backflow preventing hot plate, and the cooling hot plate. Therefore, there is a problem that the temperature of the heating means such as heaters at the four locations must be controlled.

The present invention was invented in view of these problems. An object of the present invention is to provide a thermal conductivity measuring device and a thermal conductivity measuring method.

In the present invention, "one direction side" means the same direction, and "other direction side" means the opposite direction to the one direction side and the same direction.

The thermal conductivity measuring device according to claim 1 is a thermal conductivity measuring device for determining the thermal conductivity of a flat plate-shaped test piece having parallel planes on both sides. a main hot plate disposed parallel to the hot cooling plate and capable of closely contacting a central region of the surface of the test piece on the other side opposite to the one direction side; A flat plate-shaped heat insulating material that forms a contact state with the surface of the hot plate on the other direction side, and a peripheral edge area on the one direction side that can be in close contact with the peripheral edge area on the surface on the other side of the test piece and on the one direction side a protective and backflow-preventing hot plate having a central region in contact with the surface of the heat insulating material on the other side, and the main heat A temperature measuring means is provided in which a concave portion is formed in which the plate and the heat insulating material are fitted, and the heat flow in the thickness direction from the main hot plate side surface of the test piece to the cooling hot plate side surface can be measured. It is characterized by

The thermal conductivity measuring apparatus according to claim 2 is characterized in that in claim 1, the inner peripheral wall surface of the recess surrounds the main hot plate and the heat insulating material, and the inner peripheral wall surface of the recess and the outer periphery of the main hot plate A thermal resistor is interposed between the side surface and the inner peripheral wall surface of the recess and the outer peripheral side surface of the heat insulating material forms a contact or non-contact facing state, and the bottom surface of the recess is the other direction side of the heat insulating material. characterized by forming a contact state with the surface of

The thermal conductivity measuring device according to claim 3 is the thermal conductivity measuring device according to claim 1 or 2, wherein the size of the protective and anti-backflow hot plate is a square with a side length of 0.05 m or more and less than 0.2 m It is characterized by being circular with a diameter of 0.05 m or more and less than 0.2 m.

A fourth aspect of the present invention is a thermal conductivity measuring apparatus according to any one of the first to third aspects, wherein the heating means are provided at three locations: the cooling hot plate, the main hot plate, and the protective and anti-backflow hot plate. It is characterized in that it is provided in a limited manner.

The thermal conductivity measuring device according to claim 5 is the thermal conductivity measuring device according to any one of claims 1 to 4, wherein the surface on the one side of the protective and anti-backflow hot plate has a thermal conductivity It is characterized by pasting a sheet-like heat resistance member with a low modulus.

The thermal conductivity measuring apparatus according to claim 6 is the thermal conductivity measuring apparatus according to any one of claims 1 to 5, wherein from the one direction side of the cooling hot plate, the main hot plate, the heat insulating material, and the protective and anti-backflow hot plate The arrangement order in the other direction is from top to bottom, from bottom to top, from left to right, or from right to left.

The thermal conductivity measuring method according to claim 7 is a thermal conductivity measuring method for determining the thermal conductivity of a flat plate-shaped test piece having parallel planes on both sides, wherein the test piece is measured in one direction. a cooling hot plate that can be in close contact with the side surface of the test piece; It is sandwiched between a protective and backflow prevention hot plate that can be in close contact with the peripheral area of the surface of the main hot plate, and a flat heat insulating material is brought into contact with the surface on the other side of the main hot plate, and the one direction of the protective and backflow prevention hot plate The inner peripheral wall surface of the recess and the outer peripheral side surface of the main hot plate are provided with a heat resistor over the entire circumference. The inner peripheral wall surface of the recess and the outer peripheral side surface of the heat insulating material form a facing state of contact or non-contact over the entire circumference, and the bottom surface of the recess and the surface of the heat insulating material on the other side are in contact with each other. the main hot plate and the protective and backflow-preventing hot plate are insulated to eliminate the temperature difference between the main hot plate and the protective and backflow-preventing hot plate, and the cooling hot plate is The cold temperature of the test piece is controlled to be lower than the high temperature of the main hot plate, and the heat flow in the thickness direction from the main hot plate side surface to the cooling hot plate side surface of the test piece is measured. do.

The method for measuring thermal conductivity according to claim 8 is characterized in that, in claim 7, a sheet-like sheet having a low thermal conductivity is applied to a surface on one side of the protective and anti-backflow hot plate in a range where it can be closely attached to the test piece. is attached to suppress heat transfer from the protective and backflow preventing hot plate to the test piece.

In the invention according to claim 1 or 7, by eliminating the temperature difference between the main hot plate and the protective and anti-backflow hot plate, the main hot plate and the protective and anti-backflow hot plate are brought into thermal equilibrium. can be maintained, and heat transfer from the main hot plate to the protective and anti-backflow hot plate side can be prevented. As a result, a steady-state one-dimensional heat flow can flow in the test piece from the main hot plate side surface in the thickness direction of the test piece toward the cooling hot plate side surface. can be used to determine the thermal conductivity of materials with low thermal conductivity with the same level of accuracy as the thermal conductivity measurements of JIS A 1412-1 (protected hot plate method).

In addition, in JIS A 1412-1 (protective hot plate method), the size of the protective hot plate surrounding the cooling hot plate and the main hot plate is a circle with a diameter of 0.2 m to 1 m or a length of 0 on one side. A square of 2 m to 1 m is defined as a standard size, and a circle with a diameter of 0.3 m or a square with a side length of 0.3 m is defined as the standard size. It was possible to reduce the size of the protective and anti-backflow hot plate surrounding the . Therefore, the size reduction and structural simplification of the thermal conductivity measuring device could be realized.

The invention according to claim 2 or 7 can eliminate heat transfer from the main hot plate to the protective and anti-backflow hot plate.

In the invention according to claim 3, the size of the protective and backflow prevention hot plate surrounding the cooling hot plate and the main hot plate is a square with a side length of 0.05 m or more and less than 0.2 m or a diameter of It could be reduced to a circular size of 0.05 m or more and less than 0.2 m. Therefore, conventionally, it was not possible to measure the thermal conductivity of a square test piece with a side length of less than 0.2 m or a circular test piece with a diameter of less than 0.2 m. It is now possible to measure the thermal conductivity of square specimens with a length of less than 0.2 m or circular specimens with a diameter of less than 0.2 m.

According to the fourth aspect of the invention, the number of heating means can be reduced to three compared to the five in Patent Document 1 and the four in Non-Patent Document 1, thereby simplifying temperature control and heating. We were able to reduce the size of the conductivity measuring device and reduce the manufacturing cost.

The invention according to claim 5 or 8 can eliminate the surface temperature difference between the test piece sides of the main hot plate and the protective and anti-backflow hot plate, and has the effect of creating a more ideal measurement condition. Play.

According to the sixth aspect of the present invention, it is possible to freely select the arrangement direction of the cooling hot plate, the main hot plate, and the protective and anti-backflow hot plate, which are components of the thermal conductivity measuring device.

BRIEF DESCRIPTION OF THE DRAWINGS It is a structure explanatory drawing explaining the basic structure of the thermal conductivity measuring apparatus which is this invention. FIG. 2 is a configuration explanatory diagram for explaining the basic configuration of a thermal conductivity measuring apparatus in which the low-temperature constant-temperature water bath in FIG. 1 is replaced with an ice-temperature constant-temperature water bath; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration explanatory diagram for explaining the basic configuration of a thermal conductivity measuring device according to JIS A1412-1 protective hot plate method. FIG. 2 is an explanatory diagram for explaining the configuration of temperature measuring means of the thermal conductivity measuring device of the present invention; It is an explanatory diagram of the installation state of the thermocouple embedded in the main hot plate, (a) is an explanatory diagram of the arrangement of the main hot plate, the heater, and the main hot plate thermocouple in a plan view, and (b) is a G arrow. FIG. 3 is an explanatory diagram of the arrangement of the protective and backflow prevention hot plate and the main hot plate thermocouple from the naked eye. FIG. 2 is an explanatory diagram for explaining the configuration of a temperature measuring means of a thermal conductivity measuring device according to JIS A1412-1 protective hot plate method. It is an explanatory view explaining composition of various heat plates etc. of a thermal conductivity measuring device of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram for explaining components such as various hot plates of the thermal conductivity measuring apparatus of the present invention, where (a) is an explanatory diagram of the main hot plate and the heat insulating material, and (b) is an explanation of the protective and backflow preventing hot plate; It is a diagram. It is explanatory drawing of the wiring state of the thermopile provided in the heat insulating material, (a) is wiring explanatory drawing which shows a wiring state by the cross-sectional structure of heat insulating material, (b) is explanatory drawing which shows a wiring route by planar view of heat insulating material. It is explanatory drawing which shows the wiring route with which (c) differs from (b). FIG. 4 is an explanatory diagram of a method of installing thermocouples for measuring the surface temperatures of the protective and anti-backflow hot plate and the main hot plate. FIG. 4 is an explanatory diagram of a state in which a tape, which is a heat resistance member, is stuck on a protective and backflow preventing hot plate; FIG. 2 is a diagram showing thermal conductivity measurement results of a thermal conductivity measuring device according to JIS A1412-1 protective hot plate method and a thermal conductivity measuring device of the present invention. In the present invention, in the case where one thermocouple for measuring the surface temperature difference between the main hot plate and the protective and backflow preventing hot plate is provided in the heat insulating member, and in the case where a thermopile in which ten thermocouples are connected in series is provided, the heat FIG. 4 is a diagram showing the temperature difference between the main hot plate and the protective and backflow prevention hot plate over time from the start of operation of the conductivity measuring device. FIG. 5 is a diagram showing measured values of thermal conductivity over time from the start of operation of the thermal conductivity measuring device in the conventional thermal conductivity measuring device and the thermal conductivity measuring device of the present invention. When the power consumption of the main heating plate is changed, the surface temperature of the main heating plate and the protective and backflow prevention hot plate with and without the tape, which is a heat resistance member, attached on the protection and backflow prevention hot plate. FIG. 10 is a diagram showing the difference; FIG. 4 is an explanatory diagram of a state in which the cooling hot plate and the main hot plate are separated from each other; FIG. 10 is an explanatory diagram of a state in which the hot cooling plate is lowered and the test piece is sandwiched between the hot cooling plate and the main hot plate and brought into close contact with each other at the top and bottom;

The present invention is a technique for determining thermal conductivity, and generally known methods for determining thermal conductivity include, for example, JIS A1412-1 protective hot plate method. In the protected hot plate method, as shown in FIG. 3, the inside of a flat plate-shaped test piece 101 sandwiched between two parallel plates having isothermal surfaces with different temperatures is heated so that it becomes a one-dimensional heat flow in a steady state. It is a method of controlling and measuring heat transfer characteristics such as thermal resistance and thermal conductivity in the thickness direction of the test piece 101. In a steady state, the heat flow flowing in the measurement area is measured, and the heat flow and heat transfer are measured. In this method, the thermal conductivity is calculated based on the area, the temperature difference of the test piece, and the thickness of the test piece 101 .

A configuration of a conventional thermal conductivity measuring device 100 based on the protective hot plate method will be described. As shown in FIG. 3, for example, when the shape of the cooling hot plate 102 and the test piece 101 is square, the square flat cooling hot plate 102 can be attached to the upper surface of the square flat test piece 101. A square and flat plate-shaped main hot plate 103 is provided so as to be in close contact with the lower surface of the test piece 101, and a gap 104 is provided between the outer peripheral surface of the main hot plate 103 and the main hot plate 103 to surround the main hot plate 103. A protective hot plate 105 having a rectangular frame shape in plan view is arranged so as to form a flat plate, and the main hot plate 103 and the protective hot plate 105 are disposed below the main hot plate 103 and the protective hot plate 105. A flat plate-shaped heat insulating material 106 is arranged with its upper surface in contact with the lower surface, and a backflow prevention heat plate 107 is arranged with its upper surface in contact with the lower surface of the heat insulating material 106 below the heat insulating material 106 . ing. Note that the heating means for the cooling hot plate 102 and the backflow preventing hot plate 107 are not shown.

As shown in FIG. 6, the temperature measuring means of the conventional thermal conductivity measuring device 100 includes a thermocouple 111 for measuring the temperature of the cooling hot plate 102, a thermocouple 112 for measuring the temperature of the main hot plate 103, A differential thermocouple 113 for measuring the temperature difference between the hot plate 103 and the protective hot plate 105 and a differential thermocouple 114 for measuring the temperature difference between the main hot plate 103 and the backflow preventing hot plate 107 are provided. A main hot plate heater 121 for heating is provided inside the main hot plate 103 , and a protective hot plate heater 122 for warming is provided inside the protective hot plate 105 .

Since the conventional thermal conductivity measuring device 100 was restricted to a size of 0.2 m or more on one side when the size of the test piece was square, the inventors decided that the length of one side should be less than 0.2 m. The present invention was conceived by working on miniaturization of a thermal conductivity measuring device in which a square test piece can completely cover the main hot plate 103 and the protective hot plate 105 .

As shown in FIGS. 1, 2, 4 and 8, the thermal conductivity measuring device 1 of the present invention is a thermal conductivity measuring device for determining the thermal conductivity of a flat test piece 2 having parallel planes on both sides. 1, a cooling hot plate 3 that can be in close contact with the surface of the test piece 2 on one side, A main hot plate 4 that can be brought into close contact with the central region of the surface on the other direction side, a flat heat insulating material 5 that forms a state of contact with the surface on the other direction side of the main hot plate 4, and a peripheral edge portion on the one direction side. The protective and anti-backflow heat region can be in close contact with the peripheral edge region of the other side surface of the test piece 2, and the central region on the one side side forms a contact state with the other side surface of the heat insulating material 5. a plate 6, wherein a concave portion 30 for fitting the main hot plate 4 and the heat insulating material 5 is formed in a central region on one side of the protective and backflow preventing hot plate 6; A temperature measuring means is provided for measuring the heat flow in the thickness direction from the surface on the side of the main hot plate 4 to the surface on the side of the cooling hot plate 3 . The main hot plate thermocouple 13 and the cooling hot plate thermocouple 14 correspond to the temperature measuring means. Note that wiring is omitted and not shown in the drawings such as FIG.

The thermal conductivity measuring device 1 is provided with heating means, and the heating means includes a heater 25 for heating the low-temperature water flowing in the cooling hot plate 3 and a heater 15 embedded in the main hot plate 4. , and a heater 21 for heating the high-temperature water flowing in the hot plate 6 for protection and backflow prevention.

The thermal conductivity measuring device 1 is equipped with a temperature measuring means, and the temperature measuring means is a cooling device for measuring the temperature of the test piece 2 side of the cooling hot plate 3 as shown in FIG. A hot plate thermocouple 14, a main hot plate thermocouple 13 for measuring the temperature of the main hot plate 4 on the side of the test piece 2, and the temperature between the main hot plate 4 and the protective and anti-backflow hot plate 6. They are provided at three locations on the thermopile 40 for measuring the difference. Further, when the temperature of the cooling hot plate 3 or the protective and backflow preventing hot plate 6 is not heated by a heater but by flowing low temperature water or high temperature water, the high temperature water is heated by the protecting and backflow preventing hot plate 6. In the case of the configuration in which the hot and cold water flows in the constant temperature water tank 22, the temperature measurement means 52 for the high temperature water is provided in the constant temperature water tank 22, and in the case of the configuration in which the cold and hot water flows in the cooling hot plate 3, the temperature measurement means 52 for the low temperature water is provided in the constant temperature water tank 26. Means 51 are provided.

For example, as shown in FIGS. 16 and 17, the thermal conductivity measuring device 1 has a protective and backflow preventing hot plate 6 disposed on a base 52, and a supporting post/guide 54 erected on the base 52. Along the line, an elevating unit 53 including the cooling hot plate 3 can be freely elevated by rotating the knob 51 . A piping 18 through which low-temperature water flows from a constant temperature water tank 26 is connected to the cooling hot plate 3, and a piping 19 through which high-temperature water flows from a constant temperature water tank 22 is connected to the protection and backflow prevention hot plate 6. . Then, as shown in FIG. 16, the test piece 2 is set while the elevating unit 53 is raised, and as shown in FIG. It is sandwiched between the plate 4 and the heat plate 6 for protection and backflow prevention and brought into close contact.

Further, the cooling hot plate 3, the main hot plate 4, the heat insulating material 5, and the protective and backflow preventing hot plate 6, which are the elements constituting the thermal conductivity measuring device 1, are measured from the one direction side to the other direction side. The arrangement order may be from top to bottom, from bottom to top, from left to right, or from right to left. The description of the thermal conductivity measuring device 1 or the thermal conductivity measuring method is based on the case where the arrangement order is from top to bottom, and from the hot plate 4 to the cooling hot plate 3 side in the thickness direction of the test piece 2. A case in which the heat flow is directed upward will be described below.

The test piece 2 has parallel flat plates on both sides, and the upper and lower surfaces of the test piece 2 are finished smooth so as to be able to adhere to the cooling hot plate 3 , the main hot plate 4 and the protective and backflow preventing hot plate 6 . Then, the surfaces of the cooling hot plate 3 on the side to be brought into close contact with the test piece 2 and the surfaces of the main hot plate 4 and the protective and backflow preventing hot plate 6 on the side to be brought into close contact with the test piece 2 are finished smooth. .

As shown in FIGS. 1, 7, and 8(a), the main hot plate 4 is surrounded by the protective and anti-backflow hot plate 6, which is square in plan view and has a side length of, for example, 0.1 m. , which is smaller in size than the protective and backflow prevention hot plate 6. As shown in FIG. A thermocouple 13 is embedded, and the main body 12 is made of a metal with high thermal conductivity, such as copper.

As for the mode of arrangement of the heater 15 and the main hot plate thermocouple 13, as shown in FIG. The power supply line 15a and the voltage measurement line 15b are wired so that they do not come into contact with the main hot plate thermocouple 13 and the main hot plate 4 has a uniform temperature over the entire area. Then, as shown in FIG. 5B, for example, a cutout portion 35 is formed in the protective and backflow prevention hot plate 6 in side view, and the cutout portion 35 is provided with the main hot plate thermocouple 13 and the heater. 15 and the wiring of the thermopile 40 are inserted.

As shown in FIGS. 7 and 8B, the protective and backflow-preventing hot plate 6 is in the form of a quadrangular prism having a square outer shape in plan view, with a concave portion 30 having an opening in one direction. is. The size and shape of the protective and backflow-preventing hot plate in plan view is a square with a side length of 0.05 m or more and less than 0.2 m or a diameter of 0.05 m or more and less than 0.2 m. circular. More preferably, it is a square with a side length of 0.07 m or more and less than 0.15 m or a circle with a diameter of 0.07 m or more and less than 0.15 m. A 1 m square or a circle with a diameter of 0.1 m. This made it possible to measure the thermal conductivity of square test pieces with a side length of 0.05 m or more and less than 0.2 m or circular test pieces with a diameter of 0.05 m or more and less than 0.2 m. A square with a side length of less than 0.05 m or a circle with a diameter of less than 0.05 m is extremely difficult to manufacture, and a square with a side length of 0.2 m or more or a diameter of 0.2 m or more A circular shape is not desirable because it goes against the purpose of miniaturizing the apparatus of the present invention.

The protective and backflow prevention hot plate 6 is made of the same material as the main hot plate 4, and as shown in FIG. The upper surface of the protective and anti-backflow hot plate 6 is formed so that the upper surface of the protective and anti-backflow hot plate 6 is in contact with the upper surface of the protective and anti-backflow hot plate 6 at the same time as the upper surface of the protective and anti-backflow hot plate 4 . A high-temperature constant temperature water tank 22 is provided with a heating means such as a heater 21 and a temperature measuring means 52 such as a thermometer in a channel (not shown) formed inside the plate 6, and the high-temperature water in the constant temperature water tank 22 is fed by a pump 23. circulating. As a heating means, in addition to the mode in which the high-temperature water flows into the protective and backflow-preventing hot plate 6, a mode in which a heater (not shown) is provided inside the protective and backflow-preventing hot plate 6 is also available. good.

Then, as shown in FIGS. 1, 4, 6, 7 and 8(b), a concave portion 30 is formed in the upper portion of one direction side, and the main hot plate 4 and the heat insulating material 5 are laminated in the concave portion 30. It is made to fit. The inner peripheral wall surface 31 of the recess 30 surrounds the laminated main hot plate 4 and the heat insulating material 5, and a heat resistor is provided between the inner peripheral wall surface 31 of the recess 30 and the outer peripheral side surface of the main hot plate 4. 7 are interposed, the inner peripheral wall surface 31 of the recess 30 and the outer peripheral side surface of the heat insulating material 5 form a facing state of contact or non-contact, and the bottom surface 32 of the recess 30 is on the other side of the heat insulating material 5. It forms a contact state with the surface.

The upper surface on the one side of the main hot plate 4 can be brought into close contact with the surface on the other side of the test piece 2 together with the upper surface on the one side of the protective and backflow preventing hot plate 6, and the entire side surface of the main hot plate 4 can be attached. and the inner peripheral wall surface 31 of the concave portion 30 of the protective and backflow preventing hot plate 6 form a thermal resistor 7 having a uniform width. The heat resistor 7 may be any one that achieves the purpose of eliminating heat transfer from the main hot plate 4 to the protective and anti-backflow hot plate 6, that is, has a heat insulation effect. It may be in the form of a gap in which air is interposed, or in the form of interposing a heat insulating material such as foamed resin. Note that FIGS. 1 and 8B show the case of a gap as an example of the thermal resistor 7. FIG.

The protective and backflow-preventing hot plate 6 is made of a metal with high thermal conductivity such as copper, the protective and backflow-preventing hot plate 6 is miniaturized, and a heating means is provided inside the protective and backflow-preventing hot plate 6. By providing a high-temperature water flow path (not shown) so that the entire temperature is uniform, the entire protective and backflow-preventing hot plate 6 can be easily maintained at a uniform high temperature. The heating means may be of a form in which the high-temperature water flows, or a form in which a heater (not shown) is provided inside the protective and anti-backflow hot plate 6 .

The heat insulating material 5 may be any material as long as it prevents heat transfer from the main hot plate 4, and is made of foamed resin, for example. As shown in FIGS. 7 and 8, the heat insulating material 5 is fitted in the concave portion 30 of the protective and backflow preventing hot plate 6, and the upper surface, which is one side, is the other side of the main hot plate 4. Formed in contact with the lower surface, the lower surface on the other side is in contact with the bottom surface 32 of the recessed portion 30 of the protective and backflow-preventing hot plate 6, and the side surface is the inner periphery of the recessed portion 30 of the protective and backflow-preventing hot plate 6. A facing state of contact or non-contact with the wall surface 31 is formed. Then, as shown in FIG. 9(a), a thermopile 40 for measuring the temperature difference between the main hot plate 4 and the protective and anti-backflow hot plate 6 and outputting a thermoelectromotive force is provided on the heat insulating material 5. It is embedded in the through hole 44 and the groove formed on the surface of the heat insulating material 5 .

The temperature measuring means for measuring the temperature difference between the main hot plate 4 and the protective and backflow preventing hot plate 6 has contact points 45c, 45d and 45e with the main hot plate 4 on the surface of the heat insulating material 5 on one side. and a thermopile 40 in which a plurality of thermocouples 41 having contact points 45a and 45b with the protective and backflow preventing hot plate 6 are provided on the other side surface of the heat insulating material 5 and connected in series.

The cooling hot plate 3 can be moved up and down in both directions of one direction and the other direction with respect to the main hot plate 4, for example, in the vertical direction. As shown in FIG. The test piece 2 is set, and the cooling hot plate 3 is lowered as shown in FIG. The size of the cooling hot plate 3 is the same as the outer shell of the protective and backflow preventing hot plate 6 in plan view, and as shown in FIG. (none), a low-temperature constant temperature water tank 26 provided with a heating means such as a heater 25 and a temperature measuring means 51 such as a thermometer is fed by a pump 27 and circulated. Further, as shown in FIG. 4, a cooling hot plate thermocouple 14 for measuring the temperature of the cooling hot plate 3 on the side of the test piece 2 is embedded in the cooling hot plate 3 . As the embedded form, as shown in FIG. 4, the cooling hot plate thermocouple 14 is inserted into a hole in the thickness direction, or formed on the surface of the cooling hot plate 3 on the side to be brought into close contact with the test piece 2. Although there is a form (not shown) in which the test piece is embedded in a groove formed in the cooling plate 3, any form may be used as long as the temperature of the cooling hot plate 3 on the side of the test piece 2 can be measured.

Then, low-temperature water is caused to flow through the piping embedded in the cooling hot plate 3 so that the temperature of the cooling hot plate 3 is lower than the temperature of the main hot plate 4 and the protective and backflow preventing hot plate 6. A low temperature is maintained by controlling the temperature. First, the temperature of the low-temperature water is set in advance so that it is lower than the set temperature of the high-temperature water flowing in the protective and anti-backflow hot plate 6 .

Then, the temperature of the low-temperature water is controlled by the temperature control means 10 for adjusting the current value of the heater 25 so that the temperature of the low-temperature water measured by the temperature measuring means 51 in the constant temperature water tank 26 becomes a preset temperature. Since the low temperature water is circulated through the constant temperature water tank 26 and the cooling hot plate 3 by the pump 27, the temperature of the cooling hot plate 3 is maintained uniformly at the temperature of the low temperature water over the entire area.

The upper surface of the test piece 2 can be brought into close contact with the lower surface of the cooling hot plate 3 . As the heating means, a heater (not shown) may be installed inside the cooling hot plate 3 instead of flowing the low-temperature water in the cooling hot plate 3 .

As shown in FIG. 2, ice 28 is put into the constant temperature water in the low temperature constant temperature water tank 26 to turn the constant temperature water into ice water, and the ice water is passed through the flow path (not shown) in the cooling heat plate 3. In the case of the configuration in which the ice water is made to flow and circulated through the channels in the constant temperature water tank 26 and the cooling hot plate 3, the temperature of the cooling hot plate 3 can be maintained at about 0° C., so the temperature of the constant temperature water tank 26 is reduced. There is an effect that the temperature measurement means 51 and the temperature control means 10 for controlling become unnecessary.

Further, the shape and size of the outer shell of the cooling hot plate 3 in plan view are the same shape and size as the outer shape and size of the protective and backflow preventing hot plate 6 in plan view.

Next, temperature control of the thermal conductivity measuring device 1 of the present invention will be described. First, set the temperature of the hot water and the temperature of the cold water. The temperature of the low temperature water is set lower than the temperature of the high temperature water.

In order to stabilize the temperature of the high-temperature water flowing in the flow path (not shown) in the protective and backflow prevention hot plate 6 at a preset high temperature, the temperature control means 11 is installed in the constant temperature water tank 22. The current value of the heater 21 is controlled so that the temperature measured by the temperature measuring means 52 becomes a preset high temperature. The high-temperature water is constantly circulated through the constant temperature water tank 22 and the flow paths in the protective and backflow preventing hot plate 6 by means of a pump 23 .

Then, the temperature of the low-temperature water flowing through the flow path (not shown) in the cooling hot plate 3 is set lower than the temperature of the high-temperature water. In order to stabilize the preset low temperature, the temperature control means 10 adjusts the current value of the heater 25 so that the temperature measured by the temperature measuring means 51 installed in the constant temperature water bath 26 becomes the preset low temperature. to control. The low-temperature water is constantly circulated through the constant temperature water tank 26 and the flow paths in the cooling hot plate 3 by means of a pump 27 .

Then, based on the temperature difference information of the thermopile 40 that measures the temperature difference between the main hot plate 4 and the protective and backflow preventing hot plate 6, the temperature control means 9 adjusts the temperature so as to eliminate the temperature difference. The current value of the heater 15 of the main hot plate 4 is controlled. As a result, the temperature difference between the main hot plate 4 and the protective and backflow preventing hot plate 6 is eliminated. Then, a one-dimensional heat flow flows inside the test piece 2 from the main hot plate 4 side toward the cooling hot plate 3 side.

Next, the temperature of the test piece 2 side of the main hot plate 4 is measured with the main hot plate thermocouple 13, the temperature of the test piece 2 side of the cooling hot plate 3 is measured with the cooling hot plate thermocouple 14, The heat flow rate (Φ) of the one-dimensional heat flow flowing through the test piece 2 is measured, the heat transfer area (A), the test piece temperature difference (ΔT), the test piece thickness (d) is obtained, and the thermal conductivity λ = ( Thermal conductivity is obtained using the following formula: heat flow rate Φ×test piece thickness d)/(heat transfer area A×test piece temperature difference ΔT).

As shown in Table 1, the time until the temperature of the conventional thermal conductivity measuring device 100 and the thermal conductivity measuring device 1 of the present invention stabilizes to a measurable temperature. The material, the thickness of the test piece is 7 mm, the upper and lower surfaces of the test piece are finished smooth, the temperature of the cooling hot plate is maintained at 0°C, and the temperature of the main hot plate is maintained at 35°C in the conventional thermal conductivity measuring device 100. The thermal conductivity measuring apparatus 1 of the present invention was controlled to maintain the temperature at 33° C., and the sampling was performed under the condition that the measurement was performed every second and the moving average was obtained in 64 seconds. The temperature difference measuring means between the main hot plate and the protective hot plate of the thermal conductivity measuring device 100 is a thermocouple, and the temperature difference measuring means between the main hot plate and the backflow prevention hot plate is a thermocouple. A means for measuring the temperature difference between the main hot plate 4 and the protective and anti-backflow hot plate 6 of the rate measuring device 1 is a thermopile 40 in which ten thermocouples are connected in series. In addition, the size of the protective and anti-backflow hot plate is a square with a side length of 0.1 m. The size of the test piece is a square with a side length of 0.1 m.

The results for the conditions in Table 1 are shown in FIG. From FIG. 14, it takes about 8 minutes for the temperature to stabilize in the temperature change graph K of the conventional thermal conductivity measuring device 100, whereas the temperature in the temperature change graph H of the thermal conductivity measuring device 1 of the present invention stabilizes. was shown to be shortened to about 3 minutes. As a result, the present invention has the remarkable effect of being able to quickly measure thermal conductivity in less than half the time of conventional devices.

In the conventional thermal conductivity measuring device 1, the present invention reduces the number of two parts, the protective hot plate 105 and the backflow preventing hot plate 107, to one, eliminates the need for the heater 122 of the protective hot plate 105, and protects the heat. The number of parts can be reduced by eliminating the need for the differential temperature measuring means 113 between the plate 105 and the main hot plate 103, and the device can be downsized, the structure can be simplified, and the manufacturing cost can be reduced.

In addition, since a predetermined number of thermocouples 41 are connected in series to the thermopile 40 for measuring the temperature difference between the main hot plate 4 and the protective and backflow preventing hot plate 6, the temperature difference is measured in series. The temperature difference can be grasped by the value obtained by multiplying the number of connected devices, and it has become possible to adjust the temperature at a finer numerical level toward zero temperature difference.

The thermocouple 41 has a circuit made of two kinds of homogeneous metal conductors. For example, as shown in FIG. The chromel wire 43 is connected as the + pole side. The wire diameter should be 0.2 mm or less. Moreover, as a method of connecting the thermocouples 41 in series, for example, as shown in FIG. For example, 10 thermocouples 41 are connected in series so that they are in contact with the lower surface of the hot plate 4 and the lower surface of the heat insulating material 5 is in contact with the upper surface of the protective and backflow-preventing hot plate 6 at a plurality of points. In this case, the temperature difference between the main hot plate 4 and the protective and backflow-preventing hot plate 6 can be increased by 10 times, in other words, the thermoelectromotive force (output voltage) proportional to the temperature difference can be increased by 10 times. This made it possible to control the temperature at a numerical value one tenth of that of a single thermocouple 41 .

The method of connecting the thermocouples 41 in series is such that the upper surface side of the heat insulating material 5 is brought into contact with the lower surface of the main hot plate 4 , and the lower surface side of the heat insulating material 5 is connected to the upper surface of the protective and backflow prevention hot plate 6 . Any path, such as the path shown in FIG. 9(c), may be used as long as the contact is made at a point. Further, if the number of thermocouples 41 is plural, the temperature difference between the main hot plate 4 and the protective and anti-backflow preventing hot plate 6 can be grasped by a magnification corresponding to the number of the thermocouples 41. The number of thermocouples 41 corresponding to the number of magnifications desired to grasp the temperature difference is provided.

Since the main hot plate 4 and the protective and anti-backflow hot plate 6 are made of the same metal with high thermal conductivity, such as copper, a short circuit between the contacts 45a and 45b and between the contacts 45c and 45d will occur. In order to prevent a short circuit with the contact 45e, for example, insulating films (not shown) are pasted on the upper and lower surfaces of the heat insulating material 5, respectively.

Comparing the thermal conductivity obtained by the thermal conductivity measuring device 1 of the present invention with the thermal conductivity obtained by the thermal conductivity measuring device 100 according to the conventional protected hot plate method, as shown in FIG. , test piece A (trade name Neomafoam, Asahi Kasei Construction Materials Co., Ltd., thermal conductivity 0.02 W / mK), test piece B (trade name Otokui 5, Rix Co., Ltd., thermal conductivity 0.0526 W / mK) have almost the same thermal conductivity. From this, it was proved that the thermal conductivity obtained from the thermal conductivity measuring device 1 of the present invention shows the same numerical value as the thermal conductivity obtained from the conventional method.

In addition, the thermal conductivity of the catalog value of the test piece C (silicon rubber, Shin-Etsu Chemical Co., Ltd., thermal conductivity 0.2 W / mK) and the thermal conductivity measurement device 1 of the present invention were measured and obtained. The thermal conductivity of the test piece C was approximately the same value at 0.2 W/mK. This proves that the thermal conductivity obtained from the thermal conductivity measuring apparatus 1 of the present invention is the same number as the thermal conductivity obtained from the conventional method.

Next, in the present invention, as a means for measuring the temperature difference between the main hot plate 4 and the protective and anti-backflow hot plate 6, the thermopile 40 in which ten thermocouples 41 are connected in series and one thermocouple 41 The time required for the temperature difference to stabilize was compared in each case. In FIG. 13, the vertical axis represents the temperature difference between the main hot plate 4 and the protective/backflow-preventing hot plate 6, and the horizontal axis represents the elapsed time from the measurement start time of the thermal conductivity measuring apparatus 1. As shown in FIG.

As shown in FIG. 13, when the thermopile is not used and there is only one thermocouple, the time until the temperature difference stabilizes is the temperature difference graph F, which shows that the temperature is about -0.8°C at first. The difference overshot to 1.1°C and stabilized at about -0.5°C to -0.7°C after about 12 minutes. On the other hand, when using the thermopile 40 in which ten thermocouples are connected in series, the time required for the temperature difference to stabilize is about 5°C from about 0.1°C at first. It stabilized at 0.1°C to 0.2°C after minutes. From this, it was shown that the thermopile in which ten thermocouples are connected in series stabilizes the temperature difference at a value close to 0° C. more quickly than in the case of one thermocouple.

Next, in the thermal conductivity measuring apparatus 1 of the present invention, the heating means of the main hot plate 4 is placed on the surface of the protective and anti-backflow hot plate 6 in one direction and in the range where the test piece 2 can be closely contacted. A sheet-like heat with low thermal conductivity made of a material that eliminates the temperature difference between the surface temperatures of the main hot plate 4 and the protective and backflow preventing hot plate 6 on the side of the test piece 2 by changing the power consumption of the heater 15. A resistance member 60 is attached.

As shown in FIG. 10, a thermocouple 62 for measuring the surface temperature of the main hot plate 4 and a thermocouple 61 for measuring the surface temperature of the protective and anti-backflow hot plate 6 are installed. The temperature and the surface temperature of the protective and anti-backflow hot plate 6 were compared. As a result, as shown in FIG. 15, when the power consumption of the heater 15 of the main hot plate 4 increases, the temperature difference between the main hot plate 4 and the protective and backflow prevention hot plate 6 increases as indicated by the temperature difference transition graph M. The temperature difference tends to drop sharply, and when the power consumption of the main hot plate 4 exceeds 1 W, the temperature difference at the boundary between the main hot plate 4 and the test piece 2 reaches a maximum of 1.4°C. It was shown that the temperature decreased.

Therefore, in order to accurately measure the thermal conductivity of the test piece 2, it is necessary to minimize the difference in surface temperature between the main hot plate 4 and the protective and anti-backflow hot plate 6 as much as possible. Therefore, in order to eliminate the difference of 1.4° C., as shown in FIG. The masking is made of a material having a low thermal conductivity and having a rectangular frame shape in a plan view, which is made of a material that eliminates the difference in surface temperature between the test piece side of the main heating plate and the protective and backflow prevention heating plate by changing the power consumption of the heater 15. A sheet-like heat resistance member 60 such as a tape is attached.

The results are shown in FIG. As the heat resistance member 60, a blue vinyl tape and a yellow masking tape were tested. The results are shown in graph T for the blue vinyl tape and graph Y for the yellow masking tape. In the case of the blue vinyl tape, when the power consumption of the heater 15 of the main hot plate 4 becomes 1 W, the temperature difference between the surface temperatures of the main hot plate 4 and the protective and backflow preventing hot plate 6 on the side of the test piece 2 is about -0. 3 ° C., and in the case of yellow masking tape, even if the power consumption of the heater 15 of the main hot plate 4 is 1 W, the surface temperature of the test piece 2 side of the main hot plate 4 and the protective and backflow prevention hot plate 6 It was confirmed that there is no temperature difference between the two. This means that the difference in surface temperature between the main hot plate 4 and the protective and backflow-preventing hot plate 6 on the side of the test piece can be reduced regardless of changes in the power consumption of the heater 15 of the main hot plate 4 by selecting the material. suggests that it is possible to eliminate

Next, the thermal conductivity measuring method of the present invention will be explained. The thermal conductivity measuring method is a thermal conductivity measuring method for determining the thermal conductivity of a flat plate-shaped test piece 2 having parallel planes on both sides. A cooling hot plate 3 that can be in close contact with the surface, a main hot plate 4 that can be in close contact with the central region of the surface of the test piece 2 on the other side opposite to the one direction side, and the test piece 2. It is sandwiched between a protective and backflow prevention hot plate 6 that can be in close contact with the peripheral area of the surface on the other side, and a flat heat insulating material 5 is brought into contact with the surface on the other side of the main hot plate 4 to protect and backflow. A concave portion 30 for fitting the laminated main hot plate 4 and the heat insulating material 5 is formed on the surface of the preventing hot plate 6 on one side, so that the main hot plate 4 and the protective and backflow preventing hot plate 6 are formed. and control the cold temperature of the cooling hot plate 3 to be lower than the high temperature of the main hot plate 4, and the cooling from the main hot plate 4 side surface of the test piece 2 The heat flow in the thickness direction to the hot plate 3 side surface is measured.

The inner peripheral wall surface 31 of the recess 30 and the outer peripheral side surface of the main hot plate 4 are interposed with the heat resistor 7 over the entire circumference, and the inner peripheral wall surface 31 of the recessed portion 30 and the outer peripheral side surface of the heat insulating material 5 are interposed. forms a contact or non-contact opposing state over the entire circumference, and is brought into contact with the bottom surface 32 of the recess 30 and the surface of the heat insulating material 5 on the other direction side, and the main hot plate 4 and the protection and backflow prevention The space between the hot plates 6 is insulated.

Further, the temperature control for eliminating the temperature difference is such that the contact point 45 with the surface of the main hot plate 4 on the other side is formed on the surface on the one side of the heat insulating material 5 and on the surface on the other side of the heat insulating material 5. The temperature difference is multiplied by the number of the thermocouples 41 connected in series by a thermopile 40 in which a plurality of thermocouples 41 having contact points 45 with the surface on one side of the protective and backflow prevention hot plate 6 are connected in series. temperature control.

Then, the power consumption of the main hot plate is changed so that the protective and anti-backflow heat plate and the protective and backflow-preventive heat are changed to the one-direction side surface of the protective and backflow-preventing hot plate 6 within a range where the test piece 2 can be closely contacted. A sheet-like heat resistance member 60 made of a material that eliminates the temperature difference in the surface temperature of the test piece side of the plate and having a low thermal conductivity is pasted, and heat is transferred from the protective and backflow prevention hot plate 6 to the test piece 2. is suppressed.

REFERENCE SIGNS LIST 1 thermal conductivity measuring device 2 test piece 3 cooling hot plate 4 main hot plate 5 heat insulating material 6 protective and backflow preventing hot plate 7 thermal resistor 9 temperature control means 10 temperature control means 11 temperature control means 12 main body 13 main hot plate Thermocouple 14 Cooling hot plate thermocouple 15 Heater 15a Voltage measurement line 15b Feeder line 18 Piping 19 Piping 21 Heater 22 Constant temperature water tank 23 Pump 25 Heater 26 Constant temperature water tank 27 Pump 28 Ice 30 Recess 31 Inner peripheral wall surface 32 Bottom surface 35 Notch 40 Thermopile 41 Thermocouple 44 Through hole 45 Contact 51 Temperature measurement means 52 Temperature measurement means 60 Thermal resistance member

Claims (8)

A thermal conductivity measuring device for determining the thermal conductivity of a flat plate-shaped test piece having parallel planes on both sides,
a cooling hot plate that can be brought into close contact with the surface of the test piece on one side; a main hot plate that can be brought into close contact with the other side of the main hot plate; a protective and anti-backflow hot plate that can be brought into close contact with the peripheral area and whose center area on one side is in contact with the surface of the heat insulating material on the other side;
forming a concave portion in which the main hot plate and the heat insulating material are fitted in a central region on one side of the protective and anti-backflow hot plate;
A thermal conductivity measuring apparatus comprising temperature measuring means capable of measuring a heat flow in a thickness direction from the main hot plate side surface of the test piece to the cooling hot plate side surface thereof. The inner peripheral wall surface of the recess surrounds the main hot plate and the heat insulating material, a heat resistor is interposed between the inner peripheral wall surface of the recess and the outer peripheral side surface of the main hot plate, and the inner peripheral wall surface of the recess is and the outer peripheral side surface of the heat insulating material form a facing state of contact or non-contact, and the bottom surface of the recess forms a contact state with the surface of the heat insulating material on the other direction side. A thermal conductivity measuring device as described. The size of the protective and anti-backflow hot plate is a square with a side length of 0.05 m or more and less than 0.2 m or a circle with a diameter of 0.05 m or more and less than 0.2 m. The thermal conductivity measuring device according to claim 1 or 2. 4. The heat conduction according to any one of claims 1 to 3, characterized in that the heating means are provided only at three locations, namely, the cooling hot plate, the main hot plate, and the protective and anti-backflow hot plate. Rate measuring device. Claims 1 to 4, characterized in that a sheet-like heat resistance member having a low thermal conductivity is pasted on a surface on one side of the protective and backflow-preventing hot plate in a region where the test piece can be brought into close contact. The thermal conductivity measuring device according to any one of 1. The order of arrangement of the cooling hot plate, the main hot plate, the heat insulating material, and the protective and backflow preventing hot plate from the one direction side to the other direction side is from top to bottom, from bottom to top, and leftward. 6. The thermal conductivity measuring device according to any one of claims 1 to 5, wherein the direction is either from right to left or from right to left. A thermal conductivity measuring method for determining the thermal conductivity of a flat plate-shaped test piece having parallel planes on both sides,
A cooling hot plate capable of adhering the test piece to one side surface of the test piece, and a main heat plate capable of being brought into close contact with the central region of the other side surface of the test piece opposite to the one direction side. It is sandwiched between a plate and a protective and backflow prevention hot plate that can be in close contact with the peripheral area of the surface on the other side of the test piece, and a flat heat insulating material is brought into contact with the surface on the other side of the main hot plate. ,
Forming a concave portion in which the laminated main hot plate and the heat insulating material are fitted on the one-side surface of the protective and backflow-preventing hot plate,
A heat resistor is interposed over the entire periphery between the inner peripheral wall surface of the recess and the outer peripheral side surface of the main hot plate, and the inner peripheral wall surface of the recess and the outer peripheral side surface of the heat insulating material are in contact or non-contact over the entire periphery. so that the bottom surface of the recess and the surface of the heat insulating material on the other side are in contact with each other, and the main hot plate and the protective and anti-backflow hot plate are in a heat insulating state,
performing temperature control to eliminate the temperature difference between the main hot plate and the protective and backflow prevention hot plate;
controlling the cold temperature of the cooling hot plate to be lower than the high temperature of the main hot plate;
A thermal conductivity measuring method, comprising measuring a heat flow in a thickness direction from the main hot plate side surface of the test piece to the cooling hot plate side surface. A sheet-like heat resistance member with low thermal conductivity is pasted on a surface on one side of the protective and backflow-preventing hot plate in a range where it can be closely attached to the test piece, and the protective and backflow-preventing hot plate is connected to the 8. The method of measuring thermal conductivity according to claim 7, wherein heat transfer to the test piece is suppressed.

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