JP2614062B2 - Thermal conductivity measuring device based on the direct plate method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal conductivity measuring apparatus based on a direct plate method, and a thermal conductivity measuring apparatus capable of performing both a one-sample method and a two-sample method. According to.

BACKGROUND OF THE INVENTION As one method of measuring the thermal conductivity of thermal insulation using the absolute method, a direct plate method (JIS A1413 Guarded Hotplate method, GHP
Law] is stipulated. Although this method requires two thermally and geometrically identical specimens, and the processing of this specimen, especially the processing to produce a flat surface, is extremely difficult, industrial standards around the world are based on this two-plate method. There are many things.

On the other hand, there is a measurement method called a one-sheet method using only one sample. Although this measurement method requires one more temperature control point, which is not preferable from the viewpoint of an absolute method because of many error factors, some countries require this measurement method as a standard. Therefore, in order to cope with such a demand, it is necessary to prepare a measuring device for the one-sheet method and a measuring device for the two-sheet method for one and the same sample.

The main heating plate H and the protective thermal plate G ₁ of a conventional type description conventional apparatus for one method, the protective thermal plate G _2, the heat insulating material A scissors pillar X as in the first diagram (a) a support As a result, the three persons were structurally integrated. Thus by changing the spacing between the protective thermal plate G ₂ main hot plate H, it could not be such and out of samples of any thickness therebetween. For this reason, it was impossible to divert the measurement to the two-sheet method.

On the other hand, the main heating plate H of the conventional apparatus for the two-sheet method is controlled at a constant power and not at a constant temperature. In order to divert to the single-plate method using this device, place a heat insulator above the main hot plate H, and place the low-temperature plate C ₂ on this heat insulator (this is used as the protective hot plate G ₂ for the single-plate method). corresponding) and the temperature difference between the main heat plate H must control the temperature of the cold plate C ₂ so as to be 0. Further temperature difference also between the main heating plate H protective thermal plate G ₁ is should be controlled to be zero. Since the main hot plate H is controlled at a constant power, the temperature of the main hot plate H is not constant until it reaches a steady state, and the main hot plate H and the protective hot plate G ₂ are separated from each other by a thick heat insulating material. control of the protective thermal plate G ₂ is not unstable and practical as a control system.

Furthermore, with regard to the measurement accuracy of the thermal conductivity, the error of the retarding amount measurement by heat transmitted pillars X supporting the main heat plate H and the protective thermal plate G ₁ reinforced insulation A is larger than the conventional one method Was.
In addition, the main heating plate H and the mechanical surrounding the main heating plate in the case of the two-sheet method,
Articulation Y to fill the gap between the thermal protection hot plate G ₁ by the number Kesho
The main heating plate H and the material of the protective thermal plate G ₁ is a structure integrated with the indirect section Y for There are to reduce the amount of heat flowing through this portion, forcing just use a low thermal conductivity metal I didn't get it. However, since the main heating plate H and a protective thermal plate G ₁ of the GHP apparatus for improving the accuracy of the measurement as the temperature of these surfaces is uniform, but the material of the metal as possible high thermal conductivity to be used is desired, Stainless steel or the like having a low thermal conductivity has been used for the above thermal and mechanical protection. This was necessary to the temperature difference measured correction between the main heating plate H and the protective thermal plate G ₂ to increase the accuracy particularly when the measurement of one method in the apparatus of two methods for. In any of the measurements, the fact that the temperature at several locations on the main hot plate H fluctuated randomly was a fatal defect because the temperature representative of the main hot plate H was not determined.

Object of the Invention In measuring the thermal conductivity of a sample using the direct plate method, the configuration is simplified as much as possible so that there is no need to replace the apparatus for each one-plate method or two-plate method, and the number of common parts is increased. It is an object of the present invention to provide an apparatus that can perform diversion measurement between a single-sheet method and a two-sheet method.

Means for Achieving the Object When changing from the one-sheet method to the two-sheet method,
Merely replacing the thermal insulation material A which has been laminated to the main heat board H which were used in the one method to the sample S _2, also when replacing the case to have performed two methods to one method implementation The sample S ₂ laminated on the main heating plate H is replaced with a heat insulating material A, and a metal material having good heat conductivity is adopted for the main heating plate H and the protection heating plate G ₁ , and the main heating plate H can be arbitrarily selected. achieved by providing the same function can be controlled to the same temperature of the main hot plate H functions and low-temperature plate C ₂ is controlled to a constant temperature.

1 (a) and 1 (b) are diagrams for explaining an embodiment of the apparatus of the present invention, respectively, wherein (a) shows a case where a conventional measuring method by the one-sheet method is performed. Is shown. In conventional single method measurement, mainly hot plate H and the protective thermal plate G ₁ by several pillars X penetrating the heat insulating material A, was a protective thermal plate G ₂ are structurally integrated. The column X is for imparting strength, for high thermal conductivity metal or a material close to, has been a cause of increasing the heat transfer between the protective thermal plate G ₂ and the main hot plate H.

In the present invention, an integrated structure to the waste main heat plate H, and a heat insulating plate A, spun protective thermal plate G ₂ structure. As a result, the heat transfer between the main heating plate H and the protective thermal plate G ₂ could be lead to the improvement of measurement accuracy pressing minimized.

Slightly modifying this, namely replacing the first diagram (a) in at protecting hot plate G ₂ and the heat insulating material A in the respective cold plate C ₂ and the sample S _2, and perform a measurement method by two methods (B)
Shown in In this case, the protective thermal plate G ₂ and the cold plate C ₂ needs to be made of the same material, same structure.

First, the principle of measuring the thermal conductivity of a sample will be described with reference to FIG.

In the case of the single-sheet method, one sample S ₁ was used, and in the case of the two-sheet method, two samples S ₁ and S ₂ were used.
Laminate and fix as shown in FIG. Further insulation A scissors protective thermal plate G ₂ are located in the case where the protective thermal plate G ₁ is around the main hot plate H is one method provided. In each of the one-sheet method and the two-sheet method, the cooling source W at the upper and lower ends of the apparatus and the heat insulating material A 'in contact with the cooling source W are composed of the low-temperature plates C ₁ and C ₂ , the main hot plate H and the protective hot plates G ₁ and G _2. Has the function of absorbing the heat generated by the device and transferring it to the outside of the device. These cooling sources W and insulation A 'are at relatively low temperatures, e.g.
It is omitted in the GHP method operation device operating at about 100 ° C. In the case of the one-sheet method, when the main hot plate H and the protective hot plates G ₁ and G ₂ are kept at the same temperature, all the heat generated in the main hot plate H flows to the low-temperature plate C ₁ . In this case, the main hot plate H and the protective hot plates G ₁ and G ₂ are thermocouples.
TH, amplifier AMP, temperature controller CON, and power supply PG for protective hot plate
Are maintained at the same temperature via two sets of temperature controllers. For two methods, half of the heat generated in the main heat plate while keeping the main hot plate H and a protective thermal plate G ₁ at the same temperature flows to the cold plate C _1, the other half heat the other Cold plate C ₂
Flows to In this case, the main hot plate H and the protective hot plate G ₁
H, amplifier AMP, temperature controller CON, and power supply PG for protective hot plate
Are maintained at the same temperature via a set of temperature controllers consisting of

Heat flow through the sample S ₁ in the steady state temperature of each part of the sample S ₁ is not changed in time in the case of a single process in this state, the temperature difference between the two sides of the sample S ₁ and the sample S ₁ determining the thermal conductivity of the sample S ₁ than the thickness of the. Whereas the average value of the heat flow through the sample S _1, S ₂ in the steady state temperature of each part of the sample S _1, S ₂ does not change temporally when the two methods, the sample
S _1, the average value and the sample S ₁ of the temperature difference between both surfaces of each of S _2, S ₂
The average value of the thermal conductivity of the samples S ₁ and S ₂ is determined from the average value of the respective thicknesses. Here, the value of the heat flow passing through the sample is the main hot plate H
Is obtained from the electric power supplied to the heater. The calculation of the thermal conductivity in each of the single-sheet method and the two-sheet method is based on the following equation.

Single-sheet method In the case of the two-sheet method Here, λ: thermal conductivity of the sample (W / m ° C) Q: power supplied to the main hot plate (W) l: sample thickness (m) A: area of the main hot plate (m ² ) θh: Temperature of main hot plate (° C) θc: Temperature of low-temperature plate (° C).

Next, examples will be described. For the case of measurement by a single method shown in FIG. 1 (a) that must be controlled accurately to be equal to that of the protective thermal plate G ₂ a temperature of the main hot plate H, the main hot plate H and a protective heat A control thermocouple TH embedded in each of the plates G ₂ is connected in series to form a control thermopile, and the output of the thermopile is used as an input to a low noise and high magnification amplifier AMP, and The amplified signal from the AMP is further input to a PID type temperature controller CON. The regulated output signal from the temperature controller CON is the power supply PG for the protective hot plate.
Is input to From this protective hot plate power supply PG, the protective hot plate G ₂
Substantially zero heat flow always 0 is a temperature difference of the protective main hot plate H hot plate G ₂ by the optimum power to the interior of the heating wire is supplied from the main heating plate H to protect the heating plate G ₂ (Complete insulation). One method is control of the protective thermal plate G _1, in each case of the two methods is same as the control of the protective thermal plate G ₂ in one method described above.

 Procedure to change from single sheet method to double sheet method.

It sets the sample S ₂ instead remove the heat insulating material A shown in FIG. 1 (a).

Turns OFF the temperature controller for controlling the temperature of the protective thermal plate G ₂ to a temperature the same temperature of the main hot plate H. That is, the configuration shown in FIG.

 The temperature of the main heating plate H is set to a certain constant temperature.

The temperatures of the low-temperature plates C ₁ and C ₂ are set to certain constant temperatures lower than the set temperature of the main hot plate H, respectively.

Start measurement and wait for steady state. Protection hot plate G ₁ is automatically controlled to be equal to the temperature of Shunetsuban H.

Set insulation A instead remove the sample S ₂ shown in FIG. 1 To change the one method from two methods (b).

Figure 1 (b) connecting the temperature controller to the terminals of the thermocouple TH which are incorporated in advance in the low-temperature plate C ₂ shown in cold plate
Controlling the temperature of the C ₂ to a temperature the same temperature of the main hot plate H. In two methods cold plates C ₁ and C ₂ must be the same structure of the same material. Accordingly, the protection hot plate G ₂ a piece method when using this as one method consists of the same structure and material as the low-temperature plate C _2. That work as a protective thermal plate G ₂ as shown the cold plate C ₂ in FIG. 1 (a).

 Set the temperature of the main hot plate to a certain temperature.

Setting the temperature of the cold plate C ₁ at a constant temperature in lower than the set temperature of the main hot plate H.

Start measurement and wait for steady state. Protection hot plate G ₁ is automatically controlled to be equal to the temperature of Shunetsuban H.

For the device of the present invention, it is necessary to slightly modify the conventional measuring device only in the following two points.

The modified structure of more comprising a layer mainly hot plate H is the first point and the protective thermal plate G ₁ top view in Figure 2, a side cross-sectional view in FIG. 3 (a), first in FIG. 3 (b) 3 shows details of a circle b portion in FIG. Ring O is provided on the inner periphery of the protective thermal plate G _1, the ring O
Screws B made of ceramic (having a low thermal conductivity) are screwed into three screw holes in the horizontal direction, and the V-groove provided on the side surface of the disk-shaped main heating plate H and the ring O are screwed. connect is then intended to integrate the main heating plate H and the protective thermal plate G ₁ by stopping the protective thermal plate G ₁ in the ring O ring fixing screw J. Incidentally, those integrated with the main heating plate H a protective thermal plate G _1, referred to herein as the heating plate.

Further protective thermal plate G ₁ and protective thermal plate of the ring O overlap portion
It drilled screw holes in G _1, a main heating plate H and a protective thermal plate G ₁ is adjusted to fall parallel and in the same plane by screwing from below the parallelism adjusting screws K in the hole. This is a necessary condition for _one surface of the sample to uniformly contact the entire surface of the main hot plate H and the protective hot plate G1.

According to the structure of the difference between the measured result of the layer or the heat insulating material A is adhered well despite a layer of the sample S ₂ can be easily replaced measurement result by one method and two methods Contribute to reduction.

Next, as a second point, with regard to the temperature control system, the control mode of the main hot plate is a system capable of controlling both the constant power control and the constant temperature control. This is applied to the temperature control of the hot plate H. Further cold plate C ₂ for two methods other functions as a low-temperature plate C ₂ of the original for the two methods, the temperature difference between the main heat plate for single method control as possible so that 0 and also functions as a protective thermal plate G _2. That is, the low-temperature plate C ₂ and the protective thermal plate G ₂ is must be the same both material and structure.

Effects The effects of the present invention are as follows.

1. A device that can perform both the single-sheet method and the two-sheet method has been realized.

2. Measurement accuracy has been improved.

3. Enables quick measurement. This can be achieved by starting in the constant temperature mode at the start of measurement, shortening the time required to reach the steady state, that is, shortening the measurement time, and switching to the constant power mode in the steady state to maintain high precision measurement. Was.

These items will be described in order as follows. Since the main hot plate H is supported by three ceramic screws having low thermal conductivity as described in the above-mentioned purpose and the means for achieving the purpose, the main hot plate H and the protective hot plate G ₁ are supported. a high thermal conductivity can be a metal and become main heat plate H and the temperature distribution on the protective thermal plate G ₁ such as copper is improved by a large margin.
In addition, a temperature control system capable of controlling the main hot plate H to an arbitrary constant temperature and a temperature control system capable of controlling the temperature of the upper low-temperature plate C _{2 to be} the same as the temperature of the main hot plate H in the case of the two-sheet method. With the three points of the provision, the versatility of both the one-sheet method and the two-sheet method was realized.

Next, regarding the measurement accuracy, the main hot plate H is supported by three points of ceramic screws.
Heat transfer by conduction between the protective thermal plate G ₁ and is reduced by a large margin,
The reason for enabling quick measurement is as follows. In the case of the measurement by the two-sheet method, measurement was conventionally performed in the constant power mode. However, both the constant power mode and the constant temperature mode in which the temperature of the main heating plate H is set to an arbitrary constant temperature at the start of the measurement are both used. A constant temperature mode is started at the start of measurement, and after the temperature reaches a steady state, the mode is instantaneously switched to the constant power mode. In the case of measurement by the single-sheet method, similarly to the case of the two-sheet method, the operation is started in the constant temperature mode, and is switched to the constant power mode in the steady state. Therefore, in the present invention, regardless of the one-sheet method or the two-sheet method, the measurement is started by constant temperature control at the start of measurement, and is performed by constant power control at the time of measurement. By the above method, the measurement accuracy in the conventional constant power mode is maintained in both the single-sheet method and the two-sheet method, and the measurement time is greatly reduced.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are diagrams for explaining the principle of the present invention. FIG. 1 (a) shows a case where a single-sheet measurement method is performed, and FIG. Insulation material A in sample S ₂
(B) shows the case where the measurement method by the two-sheet method is performed. FIG. 2 shows a modified portion for carrying out the present invention, and is a top view showing only a portion of the main hot plate H and the protective hot plate G1 surrounding the main hot plate in FIG. _1, and FIG. 3 shows a side cross section of FIG. 2, and FIG. 3 (b) is an enlarged view of a circle (b) portion in FIG. 3 (a). H: main hot plate, G _1: protective thermal plate G _2: protect the hot plate, C _1: cold plate C _2: cold plates, S _1: Sample S _2: Sample, A: heat insulating material A ': heat insulating material, W : Cooling source AMP: Amplifier, CON: Temperature controller PG: Power supply for protection hot plate, F: Heat sink POM: Pump, T: Tank O: Ring, B: Ceramic screw J: Ring fixing screw, K: Parallel Screw for adjusting the degree

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Aoshima 999 Hyakusa housing complex, 999 Hyakusa, Hino-shi, Tokyo (72) Kozo Nakamura 2-51-9 Minamidai, Nakano-ku, Tokyo Seifuso 102

Claims (4)

(57) [Claims] At least a heating plate in which a main heating plate and a protection heating plate are integrally fixed, and a low-temperature plate, wherein the amount of heat applied by the heating plate to a sample sandwiched between the heating plate and the low-temperature plate, A thermal conductivity measuring device for use in a direct plate method for measuring a heat transfer coefficient of the sample based on a temperature difference between a main hot plate and a low temperature plate, wherein the measuring device includes a protective hot plate (G ₂ ) A heat insulating material (A), a heating plate in which a main heating plate (H) and a protection heating plate (G ₁ ) are integrally fixed, and a sample (S ₁ )
And the low-temperature plate (C ₁ ) are laminated in this order, and the protective hot plate (G ₂ ) has the same structure and the same material as the low-temperature plate (C ₂ ) so that it can be used as a low-temperature plate. The main hot plate (H) and the protective hot plate (G ₁ ) are connected by connecting means (B) made of a material having a low thermal conductivity and extending horizontally from the inner periphery of the protective hot plate (G ₁ ). are connected, the measuring device is further the main hot plate and means for controlling the (H) at an arbitrary constant temperature, said cold plate (G ₂₎ the protective hot plate which is also used as a (G ₂₎ Means for controlling the temperature of the main heating plate (H) to be the same as the temperature of the main heating plate (H). during two methods measure implementation, as laminating a sample (S ₂₎ in place of the heat insulating material (a), and measuring one method two Device being characterized in that to allow shared law measurement. 2. The thermal conductivity measuring device according to claim 1, wherein said main hot plate (H), heat insulating plate (A), and protective hot plate (G ₂ ).
A device with a separate and independent structure. 3. The thermal conductivity measuring device according to claim 1, wherein a ring (O) is provided on an inner periphery of the protective hot plate (G ₁ ).
By screwing one end of the connection means (B) into the ring (O) in the horizontal direction and connecting the other end of the connection means (B) to the main heat plate (G), (G) and the protective hot plate (G ₁ ) are connected to each other, and the ring (O) and the protective heat plate are screwed by screws (K) that are vertically screwed through the protective hot plate (G ₁ ). So that the plate (G ₁ ) can be pushed down or pushed up vertically
An apparatus in which the protective hot plate (G ₁ ) and the main hot plate (H) are in the same plane. 4. The thermal conductivity measuring device according to claim 1, wherein said connecting means (B) is a ceramic screw.