JP3380903B2 - Specific heat measuring device and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a specific heat measuring apparatus and method for thermally analyzing a sample to be measured such as solid, liquid, powder or the like while changing the temperature or thermal radiant energy according to a certain program. In particular, the present invention relates to a specific heat measuring device and method for performing a thermal analysis based on the temperature of a heat source or thermal radiation energy to measure the specific heat of a sample to be measured.

[0002]

2. Description of the Related Art Conventionally, as a thermal analysis method using a twin cell, a differential thermal analysis method (DTA) and a differential scanning calorimetry (DSC) are known.

Differential thermal analysis (DTA) is a technique that records the temperature difference between two substances as a function of temperature (or time) when heating or cooling with a fixed program. That is, as shown in FIG. 10, the sample S and the thermally inactive standard substance R are packed in the cells 31 and 32 and, in contrast, are placed in the furnace 33. When the temperature of the furnace 33 is raised (decreased), the reference substance T is transferred to the furnace 3
The temperature is raised (decreased) slightly later than the temperature of 3. Sample S is
During transition, melting, reaction, etc., the temperature changes different from the steady rising (falling) temperature. Therefore, if the temperature difference between the thermocouples 34 and 35 is taken, the thermal change of the sample S can be observed.

The differential scanning calorimetry (DSC) is a method in which the thermal energy required for the temperature difference between the standard substance R and the sample S is measured as the electric energy of the auxiliary heater, and the specific heat value is derived from this result. .

In both methods, one cell 31 is filled with a standard substance R having a known thermal property, and the other cell 32 is filled with an unknown substance (sample S) to perform thermal analysis of the unknown substance. It is supposed to do. In both methods, thermal analysis is performed in the state where the same heat energy is transferred from the heat sources of both cells 31 and 32.

However, in the differential thermal analysis method (DTA), only the thermal change of the sample S is calculated, and the specific heat of the sample S cannot be measured as the measurement result. Further, in the differential scanning calorimetry (DSC), it is necessary to attach another auxiliary heat source (auxiliary electric heater) to the device to cancel the temperature difference between both cells. Therefore, the size of the apparatus becomes large, and measurement errors occur due to heat dissipation from the auxiliary electric heater and energy dissipated through the copper wire.
Furthermore, in both of the above methods, the standard substance R is used in addition to the sample S, so that the measurement is time-consuming and costly.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned drawbacks, and its object is to easily measure the specific heat of a sample to be measured by using the temperature of a heat source. Another object of the present invention is to provide a specific heat measuring device and method. In particular, it is to enable highly accurate measurement at low cost without using a reference sample or an auxiliary heat source.

Another object is to easily measure the specific heat of the solute contained in the measured sample by using the standard sample and the measured sample (solution) using the standard sample as a solvent. is there.

[0009]

A specific heat measuring device according to claim 1 includes a first sample cell 7 in which a sample S to be measured is enclosed,
An empty second sample cell 8 which is substantially the same as the first sample cell 7.
A heat source 3 for heating the first sample cell 7 and the second sample cell 8, a temperature control means 13 for heating and controlling the heat source 3, and a temperature Ts (T 'of the heated first sample cell 7).
s) and the sample cell temperature detecting means 9 for detecting the temperature Tso (T'so) of the second sample cell 8, and the heat source data detecting means 10 for detecting the heating state of the heat source 3 as heat source data.
And the detected temperatures Ts (T's) and Tso (T'so)
And a data accumulating means 14 for accumulating the heat source data,
From the data collecting means 14, the temperature Ts (T's) of the first sample cell 7 and the temperature Tso (T'so) of the second sample cell 8 are obtained.
There each time t ₁ when the same (t _1), 'extracts _(2, respective time t ₁ (t _1), t ₂ (t t ₂ t)' heat source data of the heat source 3 in ₂₎ Source data extraction means 15 for extracting
And the extracted heat source data of the heat source 3 at the respective times t ₁ (t ′ ₁ ) and t ₂ (t ′ ₂ ) and the rate of change in temperature of both sample cells 7 and 8 with time dT _s / dt (dT ′ _s). / dt), dT _so / dt (dT ' _so / dt), and a specific heat calculation means 16 for calculating the specific heat CM of the sample S to be measured.

In the specific heat measuring device according to the second aspect, the first sample cell 7 in which the sample S'to be measured in which the standard sample R and the substance B to be measured are mixed is sealed, and the standard sample R is sealed. A second sample cell 8 that is substantially the same as the first sample cell 7, a heat source 3 that heats the first sample cell 7 and the second sample cell 8, and a temperature control means that controls heating of the heat source 3. 13 and the temperature Ts of the heated first sample cell 7
(T's) and sample cell temperature detecting means 9 for detecting the temperature Tso (T'so) of the second sample cell 8, and heat source data detecting means 1 for detecting the heating state of the heat source 3 as heat source data.
0, and the detected temperatures Ts (T's) and Tso (T'so)
) And data collecting means 14 for collecting the heat source data
From the data accumulating means 14, the temperature Ts (T's) of the first sample cell 7 and the temperature Tso (T's of the second sample cell 8 are obtained.
each time t ₁ (t ₁ ), t ₂ (t ′ ₂ ) when o) is the same
And a heat source data extracting means 1 for extracting heat source data of the heat source 3 at each time t ₁ (t ₁ ), t ₂ (t ′ ₂ ).
5 and the heat source 3 at the respective times t ₁ (t ′ ₁ ) and t ₂ (t ′ ₂ ).
Based on the extraction heat source data of the above and the rate of change in temperature of both sample cells 7 and 8 with time, dT _s / dt (dT ' _s / dt) and dT _so / dt (dT' _so / dt), the measured sample S B specific heat C of the substance to be measured in
and a specific heat calculation means 16 for calculating b.

According to a third aspect of the present invention, there is provided a specific heat measuring device according to the first aspect.
Alternatively, in the specific heat measuring device according to 2, the heat source data is a temperature T (T ′) of the heat source 3, and the heat source data detecting means 10 is a temperature detecting element for detecting the temperature T of the heat source 3. To do. Therefore, the heat source data extraction means 15 extracts the temperatures Th (T'h) and Tho (T'ho) of the heat source 3 at the respective times t ₁ (t ' ₁ ) and t ₂ (t' ₂ ).

According to a fourth aspect of the present invention, there is provided a specific heat measuring device according to the first aspect.
Alternatively, in the specific heat measuring device according to the second aspect, the heat source data is the heat radiation energy W from the heat source 3, and the heat source data detecting means 10 is a heat radiation detector that detects the heat radiation energy W. . Therefore, in the heat source data extracting means 15, each time t ₁ (t ′ ₁ ), t
₂ (t ′ ₂ ), the thermal radiation energy of the heat source 3 Wh (W′h),
Who (W'ho) is extracted.

A specific heat measuring device according to a fifth aspect is the first aspect.
In the specific heat measuring device according to any one of 1 to 4, a plurality of the first sample cells are provided.

In the method for measuring specific heat according to claim 6, the first sample cell 7 in which the sample S to be measured is enclosed, and the first sample cell 7 are provided.
And an empty second sample cell 8 which is substantially the same as the above, and the temperature Ts (T's) of the heated first sample cell 7 is heated by the heat source 3.
And the temperature Tso (T'so) of the second sample cell 8 and the heat source data indicating the heating state of the heat source 3, and the detected temperatures Ts (T's), Tso (T'so) and the heat source. Data is accumulated and each time t when the temperature Ts of the first sample cell 7 and the temperature Tso of the second sample cell 8 are the same
₁ (t ′ ₁ ), t ₂ (t ′ ₂ ) is extracted, and each time t ₁ (t ′ ₁ ), t is extracted.
The heat source data of the heat source 3 at ₂ (t ′ ₂ ) is extracted, and the extracted heat source data of the heat source 3 at each time t ₁ (t ′ ₁ ) and t ₂ (t ′ ₂ ) and both sample cells 7 and 8 are extracted. Rate of temperature change dT
The specific heat CM of the sample S to be measured is calculated based on _s / dt (dT ' _s / dt) and dT _so / dt (dT' _so / dt).

In the method for measuring specific heat according to claim 7, a first sample cell 7 in which a sample to be measured S ′ in which a standard sample R and a substance to be measured B are mixed is sealed, and the standard sample R is sealed. , A second sample cell 8 that is substantially the same as the first sample cell 7 is heated by a heat source 3, and the temperature Ts (T's) of the heated first sample cell 7 and the second sample cell 8 Temperature Tso
(T'so) and the heating state of the heat source 3 are detected as heat source data, and the detected temperatures Ts (T's) and Tso (T'so) are detected.
) And the heat source data, and collects the first sample cell 7
At each time t ₁ when the temperature Tso is the same of the temperature Ts second sample cell _{8 (t '1), t} 2 (t' 2) is extracted, respective time t ₁ (t _'1) , t ₂ (t ′ ₂ ), the heat source data of the heat source 3 is extracted, and the extracted heat source data of the heat source 3 at the times t ₁ (t ′ ₁ ), t ₂ (t ′ ₂ ) and both sample cells 7 are extracted. , Temperature change rate of temperature dT _s / dt (dT ' _s / dt), dT _so / dt (dT' _so / dt)
Based on the above, the specific heat Cb of the substance B to be measured in the sample S ′ to be measured is calculated.

The method for measuring specific heat according to claim 8 is the method according to claim 6.
Alternatively, in the specific heat measuring method described in 7, the heat source data is a temperature T (T ′) of the heat source 3.
Therefore, at each time t ₁ (t ′ ₁ ), t ₂ (t ′ ₂ ), the temperatures Th (T′h) and Tho (T′ho) of the heat source 3 are extracted.

The method for measuring specific heat according to claim 9 is the method according to claim 6.
Alternatively, in the specific heat measuring method described in Item 7, the heat source data is the heat radiation energy W from the heat source 3. Therefore, at each time t ₁ (t ′ ₁ ), t ₂ (t ′ ₂ ), the thermal radiation energy Wh (W′h), Who (W′h of the heat source 3 is obtained.
o) is extracted.

A tenth aspect of the specific heat measuring method according to any of the sixth to ninth aspects is that a plurality of the first sample cells are provided.

[0019]

1 is a schematic block diagram showing an embodiment of a specific heat measuring device 1 according to the present invention. A heater 3 serving as a heat source is provided in the vacuum chamber 2. The heater 3 includes a pair of parallel ceramic heat sinks 4,
It is composed of a heating wire 5 and a drive circuit 6. A sheath nichrome wire, for example, is used as the heating wire 5, and the heat dissipation plate 4
Is laid inside. In addition, the heating wire 5 is the heat sink 4.
It may be formed on the surface of (4a, 4b). The drive circuit 6 is connected to the heating wire 5 and supplies a current to the heating wire 5 in response to a command from the control unit 11 described later.

The vacuum chamber 2 accommodates twin cells 7 and 8. The twin cells 7 and 8 are both Pyrex (registered trademark) glass tubes (diameter 8 mm, inner diameter 6 mm, length 30 mm).
Both ends of the are sealed with thin silicone rubber stoppers. One of the twin cells 7 and 8 (first sample cell 7) is filled with a sample S to be measured whose specific heat is to be measured. The other cell (second sample cell 8) is left empty.

The sample cell temperature detecting means 9 is composed of a temperature detecting element such as a thermocouple, and the temperatures Ts (T's) and Tso (T'so) of the twin cells 7 and 8 heated by the heater 3 are continuously maintained for a predetermined time. To detect. Further, the heat source data detecting means 10 is also composed of a temperature detecting element such as a thermocouple, and continuously detects the temperature T (T ′) of the heater 3 for a predetermined time.

Next, the control unit 11 will be described. The control unit 11 includes an arithmetic processing unit such as a CPU (not shown), ROM, and R.
It is composed of a storage unit such as AM and a specific heat measurement program stored in ROM. Note that, in FIG. 1, a block configuration in the control unit 11 is functionally expressed, and for example, a ROM
The functions corresponding to the respective means 13 to 16 in the control section 11 are executed by software processing by the execution program stored therein.

The input means 12 is composed of, for example, a push button switch, and the measurement is started by pressing this button.

The temperature control means 13 controls heating and cooling of the heater 3 based on a command from the CPU. Specifically, C
The drive circuit 6 for the heater 3 receives a temperature increase command from the PU.
Drive. The drive circuit 6 supplies a predetermined amount of current to the heating wire 5 based on the command. Due to the heat conduction of the heating wire 5, the temperature T of the heat dissipation plate 4 continuously rises by a predetermined temperature, for example, about 1.5 ° C. per unit time. Further, when cooling, the amount of current is gradually reduced, and similarly, the current is lowered by 1.5 ° C. per unit time.

The data accumulating means 14 accumulates the detected temperatures T, Ts, Tso (T ', T's, T'so). Specifically, the temperature of the first sample cell 7 and the temperature of the second sample cell 8 are plotted against the temperature of the heater 3 plotted at a predetermined temperature (for example, 1.5 ° C.) per unit time, and the storage unit To store. FIG. 2 shows the temperatures T, Ts, Tso (T ', T's, Ts of the first sample cell 7, the second sample cell 8 and the heater 3).
It is a graph showing the time change of T'so). (') Is the data when the temperature drops.

When the temperature Ts of the first sample cell 7 and the temperature Tso of the second sample cell 8 when the temperature of the heater 3 rises are the same (Ts = Tso), the heat source data extracting means 15 receives the data from the data collecting means 14. It extracts each time t _1, t _2, and the temperature Th of the heater 3 at the respective times t _1, t _2, Tho
To extract. Specifically, referring to each temperature data stored in the storage unit, the extraction at the times t ₁ and t ₂ and the temperatures Th and T
Extract ho. Similarly, from the data collecting means 14, the temperature T's of the first sample cell 7 when the temperature of the heater 3 is decreased.
And the temperature T'so of the second sample cell 8 is the same (T's
= Each time t of T'so) _'1, t' ₂ extracts, each time t '
_1, t 'temperature of the heater 3 in ₂ T'h, extracts the T'ho. Specifically, the time points t ′ ₁ and t ′ ₂ and the temperatures T′h and T′ho are extracted with reference to each temperature data stored in the storage unit.

The specific heat calculation means 16 is the data accumulation means 14
Based on the temperature data collected in
Temperature change rate dT_s/ dt, dT_so/ dt (dT '_s/ dt,
dT ' _so/ dt) is calculated. And the temperature rise of the heater 3
Extraction temperature Th, Tho, and temporal change rate dT_s/ dt, dT_so
/ dt and the extraction temperatures T'h and T'ho when the temperature of the heater 3 decreases
 ， Time change rate dT '_s/ dt, dT '_so/ dt and based on
Then, the specific heat CM of the sample S to be measured is calculated. The calculation method is later
I will describe.

The display means 17 is composed of, for example, a CRT or a liquid crystal display, and various output results from the data accumulation means 14, the heat source data extraction means 15 and the specific heat calculation means 16 are displayed in a visually recognizable form. It is a thing.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, the sample S to be measured is placed in the first sample cell 7 and a rubber stopper is attached. Both sample cells 7 and 8 are housed in the vacuum chamber 2. Then, the inside of the vacuum chamber 2 is evacuated (ST1).

The measurement start button of the input means 12 is pressed to start the measurement of the specific heat C _M of the sample S to be measured. First, heating control of the heater 3 is performed (ST2). An electric current is supplied to the heater 3 to raise the temperature by 1.5 ° C. per unit time. At this time, the temperature Ts of the first sample cell 7 and the temperature Tso of the second sample cell 8 are detected and stored in the storage unit. When the temperature of the heater 3 reaches the upper limit temperature, the amount of current is reduced to decrease the temperature by 1.5 ° C. per unit time. At this time, the temperature Ts of the first sample cell 7 and the temperature Tso of the second sample cell 8 are detected and stored in the storage unit (ST3).

Times t ₁ and t ₂ when the temperature Ts of the first sample cell 7 and the temperature Tso of the second sample cell 8 are the same are extracted from the storage section (ST4). The temperatures Th and Tho of the heater 3 at the times t ₁ and t ₂ are extracted (ST5). The temperatures Th and Tho of the heater 3 at these times t ₁ and t ₂ are different. This is because the heat capacities of the first sample cell 7 and the second sample cell 8 are not the same.

On the other hand, based on the temperature data accumulated by the data accumulating means 14, the time change rates dT _s / dt and dT _so / dt of the temperatures of both the sample cells 7 and 8 are calculated (ST6). Then, the temperatures Th and Tho of the extracted heater 3, the rate of change with time dT _s / dt, dT _so / dt, the mass M of the measured sample S, the mass m of the second sample cell 8 and the second sample cell 8 From the specific heat C _m ,
The specific heat C _{M of the} sample S to be measured is calculated (ST7).

Even when the temperature of the heater 3 is decreased by cooling the heater 3, the processes of ST3 to ST7 are performed.

Here, a method of calculating the specific heat CM of the sample S to be measured will be described. First, assuming that the temperature T of the heater 3, the temperature Ts of the first sample cell 7, the temperature Tso of the second sample cell 8 and the temperature Tr of the vacuum chamber 2 are, the first sample cell 7 is The relationship between the energy transferred from the heater 3 per unit time and the energy released to the inner surface of the vacuum chamber 2 is expressed by the following equation (1).

[0035]

[Equation 1]

When descending, it is expressed by the following equation (1 ').

[0037]

[Equation 2]

When the temperature of the heater 3 is decreased, the relationship between the energy transferred from the heater 3 to the second sample cell 8 in a unit time and the energy released to the inner surface of the vacuum chamber is expressed by the following equation (2). It

[0039]

[Equation 3]

When descending, it is expressed by the following equation (2 ').

[0041]

[Equation 4]

Here, all temperatures indicate absolute temperatures. σ
Is the Stefan-Boltzmann constant. dQs / dt is the thermal energy dissipated through the wire supporting the first sample cell 7 in which the sample S to be measured is enclosed. dQso
/ dt is the thermal energy dissipated through the wire supporting the empty second sample cell 8. M is the mass of the sample S to be measured, and m is the mass of the second sample cell 8.

C _M is the specific heat of the sample S to be measured when the temperature of the heater 3 is rising, C ′ _M is the specific heat of the sample S to be measured when the temperature of the heater 3 is decreasing, and C m is the first sample cell 7 and the second sample cell 7. It is the specific heat of the cell itself of the sample cell 8. A is the surface area of the sample cells 7 and 8.

Eh is an effective emissivity related to the transfer of thermal energy of the first sample cell 7, and Es is an effective emissivity related to the transfer of thermal energy of the second sample cell 8. Eh and Es have the same and constant values in both sample cells as long as the emissivity of the heater 3 and the sample cells 7 and 8 is constant and the geometrical arrangement of these is not changed.

The formula (3) obtained from the difference between the formulas (1) and (2) is shown below.

[0046]

[Equation 5]

When the temperature is decreased by cooling the heater 3, the formula (3 ') is obtained from the difference between the formula (1') and the formula (2 ').

[0048]

[Equation 6]

Th and Tho are the extraction temperatures of the heater 3 extracted by the heat source data extracting means 15 when the temperature of the heater 3 rises. Also, T'h and T'ho are
It is the extraction temperature of the heater 3 extracted by the heat source data extracting means 15 when the temperature of the heater 3 is decreased. In equations (3) and (3 ′), the energy dissipated from the wire is so small that it is ignored.

The formula (3) is stored in the storage unit, and the right side of the formula (3) is calculated according to the specific heat measurement program. And the specific heat C based on the data when the temperature rises
_M (left side) is calculated.

The storage unit stores the formula (3 '), and the right side of the formula (3') is calculated according to the specific heat measurement program. Then, the specific heat C _M '(left side) is calculated based on the data when the temperature is decreasing.

Then, the specific heat C _M and the specific heat C _M 'are averaged to finally calculate the specific heat CM. Specific heat CM is CRT1
7 is displayed on the screen.

The coefficient Eh is calculated in advance. The calculation method uses only the empty second sample cell 8. After raising the temperature with the heater 3, the temperature is lowered. And FIG.
As shown in, the temperature Tso of the second sample cell 8 when the temperature rises
And the temperatures T′so of the second sample cell 8 at the time of temperature decrease are the same (Tso = T′so), the times t ₃ and t ₄ are extracted. The temperature Tho of the heater 3 when the temperature rises and the temperature T′ho of the heater 3 when the temperature rises at the times t ₃ and t ₄ are extracted. Substituting the temperature Tho into the equation (2) and the temperature T'ho into the equation (2 ') to obtain the difference between the equations (2) and (2'), the following equation (4) is obtained. Become. Since the equation (4) is a measurable quantity, the coefficient Eh can be measured in advance. In addition, (') shows the data when descending.

[0054]

[Equation 7]

From the above, the mass M of the measured sample S is
If the mass m of the second sample cell 8 and the specific heat Cm of the second sample cell 8 are known, the following equations (3) and (3 ') are obtained when the temperature of the heater 3 rises and falls. The right side can be calculated from the measurement result, and the specific heat CM of the measured sample S can be derived.

Next, a second embodiment will be described.
In this embodiment, the second sample cell 8 is filled with the standard sample R (for example, water (solvent)), and the first sample cell 7 is mixed with the standard sample R and the substance to be measured B (for example, lysozyme). Fill the measurement sample S ′ (solute). The description of the same parts as those of the first embodiment will be omitted.

The heat capacity of the sample S ′ (solution) to be measured is C_MM
And the heat capacity of the solvent (water) is C_am _aAnd the substance to be measured
The heat capacity of B (solute) is C_bM_bAnd These include
There is a relationship below. C_MM = C_am_a+ C_bM_bEquation (5) (heater 3 temperature
(When increasing) C '_MM = C_a'm_a+ C '_bM_b… (5 ') Expression (Hee
(At the time of the temperature decrease of 3)

Here, the operation of this embodiment will be described with reference to FIG.
This will be described with reference to the flowchart of. First, the sample S ′ to be measured is enclosed in the first sample cell 7, the standard sample R is enclosed in the second sample cell 8, and the sample is placed in the vacuum chamber 2 (ST1 ′).
The processing from ST2 to ST6 is the same as in the first embodiment. After ST5 and ST6, the process shown in ST7 'is performed.
Here, ST7 'will be described.

When the temperature of the heater 3 rises due to heating, the relationship between the energy transferred from the heater 3 to the first sample cell 7 in which the sample S ′ to be measured is delivered per unit time and the energy released to the inner surface of the vacuum chamber 2 is: It is represented by the above-mentioned formula (1). Similarly, when the temperature decreases, the formula (1 ') is obtained.

When the temperature of the heater 3 rises due to heating, the relationship between the energy transferred from the heater 3 to the second sample cell 8 per unit time and the energy released to the inner surface of the vacuum chamber 2 is expressed by the following equation (6). expressed.

[0061]

[Equation 8]

Similarly, when the temperature drops, the equation (6 ') is obtained.

[0063]

[Equation 9]

From the difference between the equations (1) and (6), the following equation (7) is obtained as the difference in heat capacity.

[0065]

[Equation 10]

From the difference between the equations (1 ') and (6'), the following equation (7 ') is obtained as the difference in heat capacity.

[0067]

[Equation 11]

The left side of the equation (7) is the mass from the equation (5).
M_bHeat capacity C of substance B to be measured_bM _bBecomes Similarly,
The left side of the equation (7 ') is the mass M from the equation (5')._bTo be measured
Heat capacity C'of substance B_bM_bBecomes Quality of each of these
Quantity M_bDivide by, and the measured substance B when the temperature rises and falls
Specific heat of (solute) C_b, C '_bTo calculate. Average these
Then, the final specific heat Cb of the substance to be measured B is calculated.
It

The sample S (solution) to be measured when the temperature rises
The specific heat C _M is expressed by the following equation (8). Further, the specific heat C ′ _M of the sample S (solution) to be measured when the temperature decreases is given by the following equation (8 ′).

[0070]

[Equation 12]

[0071]

[Equation 13]

If the results are averaged, the sample S'to be measured is
The specific heat CM can be calculated.

In the above example, the temperature detecting element (thermocouple) is used as the heat source data detecting means 10 to detect the temperature of the heater 3, but the thermal radiation energy from the heater 3 is detected by contact. It may be done. In this case, a thermal radiation detector is provided instead of the thermocouple. Then, a glass infrared transmission window is provided in the vacuum chamber 2 to detect thermal radiation energy (infrared) emitted from the heater 3. Therefore, in this modification, ST5 shown in FIG.
Becomes ST5 'shown in FIG.

Then, the expressions (3), (3 ') and (4)
Expression, Expression (6), Expression (6 ′), Expression (7), Expression (7 ′),
In equations (8) and (8 ′), σT ⁴ h, σT ⁴ ho, σT ′ ⁴ h,
σT ' ⁴ ho is calculated as Wh / G, Who / G, W'h / G,
By replacing with W'ho / G, the specific heat CM of the sample to be measured and the specific heat Cb of the substance B to be measured can be derived. Here, Wh, Who, W'h, and W'ho are outputs of the thermal radiation detector, and G is an amplification degree of the thermal radiation detector. In this case, the coefficient Eh is replaced by (Eh / G).

Further, in any of the above-mentioned embodiments,
Although a pair of parallel heat dissipation plates 4 are used for the heater 3, a cylindrical heat dissipation member may be used as shown in FIG.

Further, in any of the above-mentioned embodiments,
Although the first sample cell 7 in which the measured samples S and S ′ are enclosed is one, as shown in FIG. 7, a plurality of the first sample cells 7 may be provided. As a result, the specific heats of a plurality of different measured samples S and solutes can be measured at the same time. Further, since every sample 7 to be measured is based on the second sample cell 8 at the time of the same measurement, the measurement accuracy is improved as compared with the case of separately measuring.

Further, in any of the above-mentioned embodiments, the temperature of each sample cell 7, 8 may be the temperature of each sample cell 7, 8 itself, or the sample enclosed therein. (Samples to be measured S, S ', standard sample R)
The temperature of the sample itself may be directly measured by directly contacting the thermocouple 9 with.

In each of the above-described embodiments, the sample to be measured S, S ', the substance to be measured B, the standard sample R
May be solid, liquid, powder or the like, or any substance as long as it is a mixture selected from these.

[0079]

EXAMPLES Next, specific examples of the first embodiment will be described. In this example, the specific heat C _{M of} pure water S was measured using sample cells 7 and 8 sealed with thin silicone rubber plugs at both ends of a Pyrex glass tube (diameter 8 mm, inner diameter 6 mm, length 30 mm). Two
The individual sample cells 7 and 8 are installed in the vacuum chamber 2 while being surrounded by the heat dissipation plate 4. The temperatures of the heater 3 and the sample cells 7 and 8 are measured using thermocouples 9 and 10. By supplying an electric current to the heater 3, the temperature of both sample cells 7 and 8 is set to 1.5 per minute.
Raise and lower at about ℃. Heater 3 and both sample cells 7,
A temperature of 8 is measured and the rate of change of temperature is also calculated from this result.

In order to measure the effective emissivity Eh in advance, it was measured using a Pyrex tube whose temperature change of the specific heat value is known. In addition, as shown in FIG.
It can be obtained from the data when the temperature rises and falls.
(') Shows data when descending. FIG. 8 shows the temperature change of the value of the effective emissivity Eh derived from the equation (4). It shows a substantially constant value from 10 ° C to 100 ° C.

FIG. 9 shows the results obtained by arranging the first sample cell 7 in which water is enclosed and the empty second sample cell 8 side by side and measuring the temperature when the temperature rises according to the equation (3). From this experimental result, it has been confirmed that the method according to the present invention is effectively established.

[0082]

As described above, in the specific heat measuring device and method according to the present invention, by using the temperature of the heat source,
The specific heat of the sample to be measured can be easily measured without using a reference sample or an auxiliary heat source. In particular, since the auxiliary heater is unnecessary, there is no cost, and there is no heat dissipation or energy dissipated through the copper wire that occurs when power is supplied to the auxiliary heater, so that measurement error can be suppressed.

By using the standard sample and the sample to be measured, it is possible to easily measure the specific heat of the substance to be measured contained in the sample to be measured.

Further, by providing a plurality of first sample cells in which the sample to be measured is enclosed, the specific heats of a plurality of different samples to be measured and solutes can be measured at the same time. Further, since every sample to be measured is based on the second sample cell at the time of the same measurement, the measurement accuracy is improved as compared with the case of separately measuring.

[Brief description of drawings]

FIG. 1 is a schematic block configuration diagram of a specific heat measuring device according to the present invention.

FIG. 2 is a graph showing temporal changes in temperature of a heater and twin cells when the temperature of the heater is controlled.

FIG. 3 is a flowchart of a specific heat measuring device according to the first embodiment of the present invention.

FIG. 4 is a graph showing temporal changes in temperature of a heater and an empty second sample cell when the temperature of the heater is controlled.

FIG. 5 is a flowchart of a specific heat measuring device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a modification of the heater.

FIG. 7 is a diagram showing an example using a plurality of first sample cells.

FIG. 8 is a graph showing a temperature change of the effective emissivity Eh derived by the equation (4).

FIG. 9 is a graph showing the temperature change of the specific heat obtained from the equation (3) when the temperature rises.

FIG. 10 is a diagram showing a conventional differential thermal analysis method (DTA).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Specific heat measuring device, 3 ... Heat source (heater), 7 ... 1st sample cell, 8 ... 2nd sample cell, 9 ... Sample cell temperature detection means,
10 ... Heat source data detection means, 13 ... Temperature control means, 14
... data collection means, 15 ... heat source data extraction means, 16 ...
Specific heat calculation means, B ... Measured substance, _CM ... Specific heat of measured sample S, R ... Standard sample, S (S ') ... Measured sample, Ts ...
Temperature of first sample cell, Tso ... Temperature of second sample cell, Th
... heat source temperature at time t _1, Tho ... time t heat source temperature at _2, t ₁ ... temperature and time of the first sample cell when the temperature of the second sample cell is the same first sample cell, t ₂
... Time of the second sample cell when the temperature of the first sample cell and the temperature of the second sample cell are the same

Claims (10)

(57) [Claims] 1. A first sample cell in which a sample to be measured is enclosed, an empty second sample cell that is substantially the same as the first sample cell, and the first sample cell and the second sample cell are heated. A heat source, a heat source control means for heating and controlling the heat source, a sample cell temperature detecting means for detecting the temperature of the heated first sample cell and a temperature of the second sample cell, and a heating state of the heat source. Heat source data detecting means for detecting as heat source data, data accumulating means for accumulating each of the detected temperatures and the heat source data, and a temperature of the first sample cell and a temperature of the second sample cell from the data accumulating means. Heat source data extraction means for extracting each time when the same is the same and extracting the heat source data at each time, the extracted heat source data of the heat source at each time, and the temperatures of the first and second sample cells time Rate of change and, based on a specific heat calculation means for calculating the specific heat of the sample to be measured,
A specific heat measuring device comprising: 2. A first sample cell in which a sample to be measured in which a standard sample and a substance to be measured are mixed is enclosed, and a second sample cell in which the standard sample is enclosed and which is substantially the same as the first sample cell. Sample cell, heat source for heating the first sample cell and the second sample cell, heat source control means for heating and controlling the heat source, temperature of the heated first sample cell and temperature of the second sample cell And a sample cell temperature detecting means for detecting the heat source, a heat source data detecting means for detecting the heating state of the heat source as heat source data, a data collecting means for collecting the detected temperatures and the heat source data, and the data collecting means. A heat source data extracting means for extracting each time when the temperature of the first sample cell and the temperature of the second sample cell are the same, and extracting the heat source data at each time; Specific heat calculation means for calculating the specific heat of the substance to be measured in the sample to be measured based on the extracted heat source data of the heat source and the rate of temporal change in temperature of the first and second sample cells. A specific heat measuring device characterized by the above. 3. The specific heat measuring device according to claim 1, wherein the heat source data is a temperature of the heat source, and the heat source data detecting means is a temperature detecting element for detecting the temperature of the heat source. 4. The specific heat according to claim 1, wherein the heat source data is heat radiation energy from the heat source, and the heat source data detecting means is a heat radiation detector for detecting the heat radiation energy. measuring device. 5. The specific heat measuring device according to claim 1, wherein a plurality of the first sample cells are provided. 6. The first sample heated by heating a first sample cell in which a sample to be measured is enclosed and an empty second sample cell substantially the same as the first sample cell by a heat source. The temperature of the cell, the temperature of the second sample cell, and the heat source data indicating the heating state of the heat source are continuously detected, and the temperatures and the heat source data are accumulated, and the temperature of the first sample cell and the first Each time when the temperatures of the two sample cells are the same is extracted, the heat source data at each time is extracted, and the extracted heat source data of the heat source at each time and the first and second sample cells are extracted. A specific heat measuring method for calculating the specific heat of the sample to be measured based on the rate of temperature change with time. 7. A first sample cell in which a sample to be measured in which a standard sample and a substance to be measured are mixed is enclosed, and an empty second cell in which the standard sample is enclosed and which is substantially the same as the first sample cell. A sample cell is heated by a heat source, and the temperature of the heated first sample cell, the temperature of the second sample cell, and the heat source data indicating the heating state of the heat source are continuously detected. Collecting the heat source data, extracting each time when the temperature of the first sample cell and the temperature of the second sample cell are the same, extracting the heat source data at each time, A specific heat measuring method for calculating the specific heat of the substance to be measured in the sample to be measured based on the extracted heat source data of the heat source and the rate of temporal change of the temperatures of the first and second sample cells. 8. The specific heat measuring method according to claim 6, wherein the heat source data is a temperature of the heat source. 9. The specific heat measuring method according to claim 6, wherein the heat source data is thermal radiation energy from the heat source. 10. The specific heat measuring method according to claim 6, wherein a plurality of the first sample cells are provided.