JP3791813B2 - Heat analyzer heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal analyzer that measures how the properties of a sample change when the temperature of the sample is changed. In particular, the present invention relates to a heating device for changing the temperature of a sample.
[0002]
[Prior art]
Conventionally, many types of thermal analyzers are known. For example, a thermogravimetric measurement device (TG device: Thermogravimetry device) that measures changes in the weight of a sample when the temperature of the sample is changed, or a temperature that appears between the sample and a standard substance when the temperature is changed simultaneously. Differential thermal analysis equipment (DTA equipment: Differential Thermal Analysis equipment) that measures the thermal change that occurs in the sample by measuring the difference, and when a non-vibrating load is applied while changing the temperature of the sample A thermomechanical analysis device (TMA device: Thermomechanical Analysis device) for measuring deformation and various other devices are known. What is common to various types of thermal analyzers is that the temperature of the sample is changed in accordance with a predetermined program. For this reason, a normal thermal analyzer is provided with a heating device.
[0003]
Considering a thermogravimetric measuring device (TG device) as one of the thermal analysis devices, the thermogravimetric measuring device (TG device) is a balance for measuring the weight of the sample S as shown in FIG. A mechanism 51 and a heating furnace 52 for changing the temperature of the sample S are provided. Normally, the balance mechanism 51 is surrounded by a metallic shield case 53 in order to prevent electrical noise from entering from the outside. Therefore, the heating furnace 52 is installed on the metal base using the upper surface 54 of the shield case 53 as a metal base.
[0004]
The heating furnace 52 includes a heater 55 that generates heat when energized, and the sample S is heated by heat released from the heater 55. The heating furnace 52 is required to have heat insulation and electrical insulation. The heat insulating property is a property that makes it difficult to transmit heat and can maintain a temperature difference, and more specifically, a property that does not transmit the heat generated in the heating furnace 52 to the metal base 54. . The electrical insulation is a property that has a large electrical resistance value and is difficult to transmit electricity, and more specifically, a property that can prevent leakage from the heating furnace 52 to the metal base 54.
[0005]
The reason why heat insulation is required is to prevent various measurement systems installed in the shield case 53 from being exposed to high temperatures. In addition, electrical insulation is required because the electrical control system of various measurement systems in the shield case 53 malfunctions or is destroyed in some cases when electricity to the heater 55 leaks through the metal base 54. It is for preventing.
[0006]
In a conventional heating device, a structure as shown in FIG. 4 has been adopted in order to achieve the above heat insulation and electrical insulation. That is, two ceramic plates 57a and 57b are laminated on the metal base 54 by using a metal support 56 such as stainless steel, and the heating furnace 52 is fixed by the bracket 58 on the upper ceramic plate 57a. According to this conventional structure, heat insulation and electrical insulation are achieved by the action of the two ceramic plates.
[0007]
[Problems to be solved by the invention]
Ceramics is a non-metallic inorganic material obtained through processes such as molding and firing. In general, this ceramic exhibits sufficient electrical insulation at room temperature, but when it reaches a high temperature of about 1500 ° C., the electrical insulation is extremely lowered and electric leakage is likely to occur. The reason why the ceramic plates 57a and 57b are laminated in the conventional structure shown in FIG. 4 is to prevent the electrical insulation from being lowered by keeping the temperature of these ceramic plates low.
[0008]
However, the conventional heating device has a complicated structure due to the adoption of a laminated structure of ceramic plates, so that the assembly is difficult, the maintenance work is difficult, the breakage is easy, and the component cost and the manufacturing cost increase. Further, there is a problem that the overall shape becomes large. The large overall shape means that the heat capacity of the entire heating furnace increases, and as a result, when raising or lowering the temperature of the heating furnace to control the temperature of the sample, the temperature can be quickly raised or lowered. The problem is that it cannot be done.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a heating device that is simple in structure and small in size while maintaining sufficient heat insulation and electrical insulation. And
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a heating device for a thermal analysis device according to the present invention is a heating device for a thermal analysis device that heats a sample by a heating furnace disposed on a metal base. A heating furnace support member disposed between the furnace and formed of ceramics having a heat insulating property and an electrical insulating property and supporting the heating furnace; and (2) a small area in the metal base integrally with the heating furnace support member. in placed in contact or have erected a metal base placed in contact with a small area in the heating furnace support member, and a plurality of contact pins having a heat insulating property and electrical insulation property, (3) the heating furnace And (4) an auxiliary support member disposed on the opposite side of the heating furnace support member with respect to the heating furnace, and (5) pushing the auxiliary support member by the case More, characterized in that for supporting the heating furnace in a state of sandwiching the heating furnace by the auxiliary support member and the heating furnace support member on said metal base.
[0011]
According to this heating apparatus, the heating furnace support member is brought into contact with the metal base through a contact pin in a small area, and the contact pin is formed of ceramics having heat insulating properties and electrical insulating properties. Sufficient heat insulation and electrical insulation can be maintained with only one furnace support member. As a result, the structure of the heating device can be simplified. Therefore, the assembly of the heating device is facilitated, maintenance work is facilitated, it is difficult to break, and the component cost and manufacturing cost can be reduced. Furthermore, since the overall shape of the heating device can be reduced, the heat capacity of the entire heating device can be reduced, and therefore the temperature of the heating furnace can be quickly controlled.
[0012]
The position where the contact pin is provided on the heating furnace support member is not particularly limited, but it is preferably disposed at the following position. The furnace support member formed of ceramics has sufficient electrical insulation to prevent leakage at room temperature. However, when this heating furnace support member is heated to a high temperature of about 1500 ° C., its electric resistance value becomes extremely small. Therefore, it is desirable to provide the contact pin in a low temperature region of the heating furnace support member. However, the term “low temperature” as used herein refers to a low temperature at which the electric resistance value of the heating furnace support member is set to a value that can prevent the occurrence of electric leakage from the heating furnace to the metal base.
[0013]
The contact pin can be formed integrally with the heating furnace support member by firing or the like, or the contact pin is formed separately from the heating furnace support member and then fixed to the heating furnace support member with an adhesive. You can also. The contact pin can also be raised from a metal base.
[0014]
As a specific structure of the heating furnace support member and the contact pin, the following configuration, that is, the heating furnace support member is formed of a circular, triangular, square, or other arbitrary plate material, and a plurality of contact pins are formed. The structure provided in the peripheral part distant from the center part which supports a heating furnace among heating furnace support members is employable.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a heating device according to the present invention. This embodiment is an embodiment in which the heating device of the present invention is applied to a thermogravimetric measuring device (TG device) which is one type of thermal analysis device. The TG device includes a shield case 3 in which a measurement system including the balance mechanism 1 is stored, and a heating device 11 for heating the sample S. The shield case 3 is made of a conductive metal material, and its upper surface 3a functions as a metal base on which the heating device 11 is placed.
[0016]
The balance mechanism 1 includes a balance rod 12 that swings around a fulcrum O, a support rod 13 that extends from one end of the balance rod 12 and supports a sample S, a load applying device 14 provided on one of the balance rods 12, and a balance rod. 12 and a displacement amount detection device 16 provided on the other side. The output signal of the displacement detection device 16 is sent to the weight measurement circuit 18, and the weight measurement circuit 18 controls the amount of power supplied to the load application device 14.
[0017]
The heating device 11 includes a cylindrical heating furnace 2 that stores the sample S, a heating furnace support member 7 on which the heating furnace 2 is placed, and a cylindrical case 4 that stores the heating furnace 2. A hole for passing the support rod 13 is formed in the center portion of the heating furnace support member 7 and the center portion of the bottom surface of the heating furnace 2. In addition, a heater wire 5 is spirally wound around the outer periphery of the heating furnace 2, and when the heater wire 5 is energized by the power control circuit 6, the heater wire 5 generates heat. The heating furnace support member 7 is formed in a circular shape as shown in FIG. 2 by ceramics having heat insulating properties and electrical insulating properties.
[0018]
In FIG. 2, the heating furnace 2 is installed at the central portion of the heating furnace support member 7. A plurality of, for example, three contact pins 17 are provided at equiangular intervals on a circular locus separated from the center by a distance R. These contact pins 17 are produced integrally with the heating furnace support member 7 when it is produced by molding, firing or the like. Therefore, the contact pin 17 is formed of ceramics having heat insulating properties and electrical insulating properties like the heating furnace support member 7. In addition, the contact pin 17 can be independently produced separately from the heating furnace support member 7, and the contact pin 17 can be bonded to the heating furnace support member 7 with an adhesive. Further, the contact pin 17 can be bonded to the metal base 3 a of the shield case 3.
[0019]
As shown in FIG. 1, the heating furnace support member 7 on which the heating furnace 2 is placed is placed on the metal base 3 a via the contact pins 17. An auxiliary support member 8 is disposed on the opposite side of the heating furnace support member 7 with respect to the heating furnace 2, that is, on the upper side of the heating furnace 2. The auxiliary support member 8 is formed of the same material as the heating furnace support member 7, that is, made of ceramics having heat insulating properties and electrical insulating properties, and is made in the same shape as the heating furnace support member 7. However, the contact pin 17 provided on the auxiliary support member 8 faces in the opposite direction to the heating furnace 2, that is, in the upward direction in the figure.
[0020]
The case 4 that houses the heating furnace 2 presses the contact pins 17 of the auxiliary support member 8 downward by the inner surface of the top plate portion thereof, whereby the heating furnace 2 is sandwiched between the auxiliary support member 8 and the heating furnace support member 7. It is supported in a stationary state. An annular heat insulating member 9 is installed between the heating furnace support member 7 and the auxiliary support member 8 on the entire side surface of the heating furnace 2.
[0021]
Since the thermal analysis device and the heating device of the present embodiment are configured as described above, power is supplied to the heater wire 5 of the heating furnace 2 by the power control circuit 6 and the heater wire 5 generates heat. Due to this heat generation, the heating furnace 2 becomes high temperature, and the temperature of the sample S is controlled. Thus, when the temperature of the sample S changes, if the sample S changes and its weight changes, the balance rod 12 swings, and the swing is detected by the displacement detector 16 and an output corresponding to the displacement is output. A signal is sent to the weight measurement circuit 18. The weight measuring circuit 18 sends electric power corresponding to the sent signal to the load applying device 14, thereby holding the balance rod 12 in a horizontal state. The weight measurement circuit 18 calculates a change in weight generated in the sample S based on the amount of power supplied to the load applying device 14.
[0022]
When the heating furnace 2 reaches a high temperature, the heating furnace support member 7 follows the temperature. Since the heating furnace support member 7 is made of ceramics, the electrical insulation performance is lowered when it is heated to a high temperature of a few hundred degrees. When the electrical insulation is lowered and the electric resistance value of the heating furnace support member 7 is lowered to an allowable limit value or less, there is a possibility that electric leakage occurs from the heating furnace 2 toward the metal base 3a. In order to avoid this, the distance R for providing the contact pin 17 is set to a distance sufficient to lower the temperature of the heating furnace support member 7. If it carries out like this, the electrical resistance value of the heating furnace support member 17 of the position in which the contact pin 17 was provided can be hold | maintained to the magnitude | size sufficient to be able to prevent generation | occurrence | production of an electrical leakage.
[0023]
In the thermal analysis apparatus of the present embodiment, the heating furnace support member 7 is brought into contact with the metal base 3a through a contact pin 17 in a small area, and the contact pin 17 is formed of ceramics having heat insulating properties and electrical insulating properties. . Therefore, sufficient heat insulation and electrical insulation can be maintained with only one heating furnace support member 7 not having a laminated structure. As a result, the structure of the heating device 11 can be simplified. Therefore, the assembly of the heating device 11 is facilitated, maintenance work is facilitated, it is difficult to break, and the component cost and manufacturing cost can be reduced. Furthermore, since the overall shape of the heating device 11 can be reduced in size, the heat capacity of the entire heating device can be reduced, and therefore the temperature of the heating furnace can be quickly controlled.
[0024]
As mentioned above, although this invention was demonstrated based on preferable embodiment, this invention is not limited to that embodiment, It can change variously within the range of the invention described in the claim.
For example, the heating device according to the present invention can be applied to any thermal analysis device other than the TG device. The shape of the heating furnace support member is not limited to a circular shape. The number of contact pins is not limited to three and can be more or less. The auxiliary support member 8 is used to support the heating furnace 2 in a stationary manner. The heating furnace support member 7 is fixed to the metal base 3a in a stationary manner by screws or other fastening devices. The auxiliary support member 8 is not necessary if it is fixed on the heating furnace support member 7 in a stationary manner.
[0025]
【The invention's effect】
According to the heating device of the thermal analysis device according to claim 1, the heating furnace support member is brought into contact with the metal base in a small area through the contact pin, and the contact pin is made of a ceramic having heat insulating properties and electrical insulating properties. Since it was formed, sufficient heat insulation and electrical insulation can be maintained with only one heating furnace support member having no laminated structure. As a result, the structure of the heating device can be simplified. Therefore, the assembly of the heating device is facilitated, the maintenance work is facilitated, it is difficult to break, and the component cost and manufacturing cost can be reduced. Furthermore, since the overall shape of the heating device can be reduced, the heat capacity of the entire heating device can be reduced, and therefore the temperature of the heating furnace can be quickly controlled.
[0026]
According to the heating device of the thermal analysis device according to claim 2, since the temperature of the heating furnace support member is sufficiently lowered and the contact pin can be provided at a place where the electric resistance value is sufficiently large, Leakage to the base can be reliably prevented.
[0027]
According to the heating device of the thermal analysis device of the third aspect, since the heating furnace support member is formed in a circular shape, the heat flow becomes stable.
[0028]
According to the heating device of the thermal analysis device of the first aspect , the heating furnace can be firmly supported by a simple structure in a stationary manner.
[0029]
[Brief description of the drawings]
FIG. 1 is a front sectional view showing an embodiment of a heating device and a thermal analysis device using the same according to the present invention.
2 is a bottom view of a heating furnace support member that is a main part used in the heating apparatus of FIG. 1. FIG.
FIG. 3 is a front sectional view showing an embodiment of a conventional thermal analysis apparatus.
FIG. 4 is a cross-sectional view showing an embodiment of a conventional heating device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Balance mechanism 2 Heating furnace 3 Shield case 3a Metal base 4 Case 5 Heater wire 7 Heating furnace support member 8 Auxiliary support member 9 Heat insulation member 11 Heating device 12 Balance rod 13 Support rod 14 Load application device 16 Displacement amount detection device 17 Contact pin S sample

Claims (3)

In the heating device of the thermal analyzer that heats the sample by a heating furnace arranged on the metal base,
A heating furnace support member disposed between the metal base and the heating furnace, formed of ceramics having heat insulation and electrical insulation, and supporting the heating furnace;
Integrated with the furnace support member and placed in contact with the metal base in a small area, or stood from the metal base and placed in contact with the furnace support member with a small area, and heat insulation and electrical insulation A plurality of contact pins having
A case surrounding the heating furnace;
An auxiliary support member disposed on the opposite side of the heating furnace support member with respect to the heating furnace,
The thermal analysis is characterized in that the heating furnace is supported on the metal base in a state where the heating furnace is sandwiched between the auxiliary support member and the heating furnace support member by pushing the auxiliary support member with the case. Equipment heating device.   2. The heating device of the thermal analysis apparatus according to claim 1, wherein an electric resistance value of the heating furnace support member is a value that does not cause leakage from the heating furnace to the metal base. A heating device of a thermal analyzer, characterized in that the contact pin is provided.   3. The heating device of the thermal analysis device according to claim 1, wherein the heating furnace support member is formed of a circular plate, and the plurality of contact pins support the heating furnace among the heating furnace support members. A heating device for a thermal analyzer, characterized in that the heating device is provided in a peripheral portion away from a central portion.

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