JP2016217885A - Temperature measuring device, thermal conductivity measuring device and thermal conductivity measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature measuring device, a thermal conductivity measuring device and a thermal conductivity measuring method capable of measuring surface temperatures of several objects with high accuracy and reliability in a relatively simple configuration.SOLUTION: A temperature measuring sensor 11a can measure a temperature of a measurement object 1 by being brought into contact with a surface thereof. A protection heat source sensor 11b is arranged next to or in touch with the temperature measuring sensor 11a in a manner that can exchange heat with the temperature measuring sensor 11a. The temperature measuring sensor 11a and the protection heat source sensor 11b have identical thermistors which can measure the temperature on the basis of electric resistance varied depending on the temperature and generate power at the temperature corresponding to the varied electric resistance. Control means 13 can control the electric resistance of the protection heat source sensor 11b so that the same has equal electric resistance to the temperature measuring sensor 11a when measuring the temperature with the temperature measuring sensor 11a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a temperature measuring device, a thermal conductivity measuring device, and a thermal conductivity measuring method.

  In the industrial field and the medical field, it is very important to measure the surface temperature of an object with high accuracy and high accuracy. Conventionally, in order to accurately measure the surface temperature of an object, a thermocouple, a platinum resistance temperature detector, a thermistor, a radiation thermometer, etc. are generally used. Of these, thermocouples are used to measure temperature using the thermoelectric effect in contact with the surface of the object, but in order to determine the voltage generated by the temperature difference and the temperature Since an accurate temperature of the cold junction is required, there is a problem that there is a limit to increasing accuracy and accuracy. In addition, when there is a temperature difference between the object to be measured and the surroundings, the temperature of the object changes due to heat loss to the lead wire, fixing tape, etc., and it is difficult to accurately measure the surface temperature. there were.

  The platinum resistance thermometer or thermistor measures the temperature by bringing it into contact with the surface of the object in the same way as a thermocouple, and has higher accuracy and accuracy than a thermocouple. However, it is difficult to accurately measure the temperature because the surface temperature of the object changes because the heat moves from the object to the platinum resistance thermometer or thermistor by contacting the object surface when measuring the temperature. There was a problem.

  On the other hand, a radiation thermometer measures temperature by energy radiated from an object without contact. The radiation thermometer can accurately measure the energy radiated from the surface of the object, but accurate emissivity information is separately required to determine the temperature. However, the emissivity is a parameter that depends not only on the optical properties of the object but also on the surface state, and it is very difficult to measure accurately, so it is difficult to determine the surface temperature of the object with high accuracy. There was a problem.

  Accordingly, a temperature measuring apparatus that solves these problems and performs temperature measurement with high accuracy and high accuracy using a thermistor has been developed. For example, in order to inspect the correction value of a heating detection thermistor mounted on a circuit board, an inspection apparatus equipped with a high-precision thermistor that respectively measures the surface temperature and the outside air temperature of a semiconductor element mounted on the circuit board. It has been developed (see, for example, Patent Document 1).

  Also, a device that shortens the thermistor temperature detection delay time by causing the thermistor to self-heat according to the temperature difference between the measured temperature of the thermistor and the target temperature of the thermistor corresponding to the state of the system including the thermistor (for example, Measure the heat flux escaping from the body with multiple thermistors), and measure the body temperature accurately by heating with a heater in the opposite direction to the heat flux so that the heat flux becomes zero Possible sensors (see, for example, Patent Document 3 or 4) have also been developed.

  As a method for measuring the thermal conductivity of living tissue, etc., model calculation is performed using a heat pulse decay method in which heat is pulsed to the object to be measured and the thermal conductivity is calculated from the temperature decay after heating. A method has been proposed (see, for example, Non-Patent Document 1).

JP 2009-216550 A JP 2013-164289 A Special table 2012-523003 gazette JP-A-55-29794

Nachiket M Kharalkar, Linda J Hayes and Jonathan W Valvano, “Pulse-power integrated-decay technique for the measurement of thermal conductivity”, Meas, Sci. Technol., 2008, 19, 075104

  However, in the inspection apparatus described in Patent Document 1, a thermistor is also required for the object to be measured, and there is a problem that the object to be measured is limited. Moreover, since the heat transferred from the surface of the object to be measured to the thermistor is not taken into account, there is a problem that the accuracy and accuracy of the measured temperature are still low. In the apparatus described in Patent Document 2, although the temperature measurement time is shortened, since the heat transferred from the surface of the object to be measured to the thermistor is not taken into account, the accuracy and accuracy of the measured temperature are still low. There was a problem. In the sensors described in Patent Documents 3 and 4, there is a problem that a heater is necessary in addition to a plurality of thermistors, and the configuration becomes somewhat complicated.

  The present invention has been made paying attention to such a problem, and a temperature measurement device and a thermal conductivity measurement capable of measuring the surface temperature of various objects with higher accuracy and accuracy with a relatively simple configuration. An object is to provide an apparatus and a method of measuring thermal conductivity.

  In order to achieve the above object, the temperature measuring device according to the present invention changes a predetermined physical quantity according to the temperature, can measure the temperature based on the value of the physical quantity, and changes the physical quantity to respond to the temperature. Two heat generation temperature sensors configured to be capable of generating heat and control means connected to each heat generation temperature sensor, one of the heat generation temperature sensors can measure the temperature by contacting the surface of the object to be measured The other exothermic temperature sensor is provided close to or in contact with the one exothermic temperature sensor so that heat can be exchanged with the one exothermic temperature sensor, and the control means includes the one exothermic temperature sensor. When the temperature is measured by the exothermic temperature sensor, the physical quantity of the other exothermic temperature sensor is provided so as to be equal to the physical quantity of the one exothermic temperature sensor.

  The temperature measuring device according to the present invention can measure the surface temperature of various objects using a heat generation temperature sensor whose predetermined physical quantity changes according to the temperature as follows. That is, first, one exothermic temperature sensor is brought into contact with the surface of the object to be measured. At this time, the physical quantity of the other heating temperature sensor provided close to or in contact with one heating temperature sensor is equal to the physical quantity of the one heating temperature sensor so that heat can be exchanged with one heating temperature sensor. The other exothermic temperature sensor is heated to a temperature equal to the temperature of one exothermic temperature sensor under the control of the control means. As a result, the temperature of the surface of the object to be measured is equal to the temperature of each heat generation temperature sensor, so that one heat generation temperature sensor changes to the other heat generation temperature sensor, and from the surface of the object to be measured changes to one heat generation temperature sensor. Heat can be prevented from moving. In this state, the temperature can be measured with high accuracy and high accuracy by measuring the temperature with one of the heat generation temperature sensors.

  As described above, the temperature measuring device according to the present invention is provided with the other exothermic temperature sensor (protective heat source sensor) as a non-stationary protective heat source for one exothermic temperature sensor (temperature measuring sensor) for temperature measurement. It is possible to cancel the heat flowing from the surface of the measurement object to one of the heat generation temperature sensors and measure the temperature without changing the state of the measurement object. Thereby, the surface temperature of various objects can be measured with higher accuracy and accuracy regardless of the contact method.

  The temperature measuring device according to the present invention utilizes the fact that the other exothermic temperature sensor generates heat at a temperature corresponding to the physical quantity by changing the physical quantity of the other exothermic temperature sensor, thereby enabling the temperature measurement with high accuracy and high accuracy. Measurements can be made. For this reason, it is possible to perform temperature measurement in consideration of the movement of heat from the surface of the object to be measured with a relatively simple configuration having only two exothermic temperature sensors without using a separate heater or the like. The other exothermic temperature sensor may be composed of two or more exothermic temperature sensors.

  The two exothermic temperature sensors are configured so that a predetermined physical quantity changes according to temperature, temperature can be measured based on the value of the physical quantity, and heat can be generated at a corresponding temperature by changing the physical quantity. Any material may be used, for example, a thermistor whose physical quantity is electrical resistance or a platinum resistance thermometer.

  The thermal conductivity measurement device according to the present invention includes the temperature measurement device according to the present invention, and the control unit is configured to cause the one exothermic temperature sensor to generate heat at a predetermined temperature. The physical quantity is provided so as to be controllable.

  In the thermal conductivity measuring method according to the present invention, the one exothermic temperature sensor of the thermal conductivity measuring device according to the present invention is brought into contact with the surface of the object to be measured, and the one exothermic temperature sensor is controlled by the control means. Is heated at the predetermined temperature, and then the temperature change of the surface of the object to be measured is measured by the one heating temperature sensor.

  The thermal conductivity measuring apparatus according to the present invention can measure the thermal conductivity of an object to be measured by the thermal conductivity measuring method according to the present invention. Since the thermal conductivity measuring apparatus according to the present invention can perform heating and temperature measurement of an object to be measured with one unit, the thermal response when the object to be measured is heated can be easily measured. The thermophysical properties of the measurement object can be measured with high accuracy and high accuracy. For example, it is possible to easily carry out a heat pulse attenuation method in which heat is applied in a pulsed manner to the object to be measured and the thermal conductivity is calculated from the temperature attenuation after heating. When performing this heat pulse attenuation method, conventionally, a heat source such as a thermistor is embedded in the object to be measured in consideration of heat loss to the lead wire, etc., but according to the thermal conductivity measuring device according to the present invention, For example, it is not necessary to consider heat loss or to embed a heat source, and the thermal conductivity can be measured with high accuracy and high accuracy without being invasive.

  According to the present invention, there are provided a temperature measuring device, a thermal conductivity measuring device, and a thermal conductivity measuring method capable of measuring the surface temperature of various objects with higher accuracy and accuracy with a relatively simple configuration. Can do.

BRIEF DESCRIPTION OF THE DRAWINGS (a) The front view which shows the use condition which shows the temperature measuring apparatus of embodiment of this invention, (b) It is an enlarged front view of the front-end | tip part. It is a graph which shows the temperature measurement result when the other exothermic temperature sensor which is a protection heat source of the temperature measuring apparatus shown in FIG. 1 is validated, and invalidated. 3 is a graph showing temperature responses of a temperature measurement thermistor (one exothermic temperature sensor) and a protective heat source thermistor (the other exothermic temperature sensor) during temperature measurement of the temperature measuring device shown in FIG. 1. It is a graph which shows a temperature measurement result when the thermal conductivity of water is measured by the heat pulse decay method with the temperature measuring device shown in FIG. It is a two-dimensional axisymmetric numerical calculation model used for verification of the diagnosis of malignant melanoma by the temperature measuring device shown in FIG. It is the elements on larger scale of the two-dimensional axisymmetric numerical calculation model shown in FIG. 5 corresponding to each progression degree of malignant melanoma. It is a graph which shows the relationship between the volume of malignant melanoma and the apparent thermal conductivity obtained by the model calculation based on the two-dimensional axisymmetric numerical calculation model shown in FIG. 5 and FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 7 show a temperature measuring apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the temperature measurement device 10 includes a temperature measurement sensor 11 a, a protective heat source sensor 11 b, a tube 12, and a control means 13.

  The temperature measuring sensor 11a and the protective heat source sensor 11b are thermistors having the same size and standard. The temperature measurement sensor 11a and the protection heat source sensor 11b are configured such that the electric resistance changes according to the temperature, the temperature can be measured based on the electric resistance value, and the heat can be generated at the corresponding temperature by changing the electric resistance. ing. The temperature measuring sensor 11 a and the protective heat source sensor 11 b are inserted into the tube 12 in a state of being arranged along the length direction of the tube 12. The temperature measurement sensor 11a and the protection heat source sensor 11b are arranged so as to be close to each other so that heat can be exchanged, and the lead wires 14 are taken out from the opening on the rear end side of the tube 12, respectively. The temperature measuring sensor 11a disposed on the distal end side of the tube 12 has a part (front half) protruding from the opening on the distal end side of the tube 12, and the protruding portion is brought into contact with the surface of the object 1 to be measured. Is provided so that it can be measured. The protective heat source sensor 11b disposed on the rear end side of the tube 12 is close to the side opposite to the protruding portion of the temperature measuring sensor 11a. The protective heat source sensor 11b may be in contact with the temperature measuring sensor 11a.

  In a specific example shown in FIG. 1, the temperature measuring sensor 11a and the protective heat source sensor 11b are made of glass-enclosed NTC thermistors and have an outer diameter of 0.43 mm. The tube 12 is made of FEP. The temperature measuring sensor 11a and the protective heat source sensor 11b are not limited to the thermistor, and may be made of, for example, a platinum resistance thermometer. Further, the temperature measuring sensor 11a constitutes one exothermic temperature sensor, and the protective heat source sensor 11b constitutes the other exothermic temperature sensor.

  The control means 13 is connected to the lead wires 14 of the temperature measuring sensor 11a and the protective heat source sensor 11b. The control means 13 can measure the temperature by measuring the electrical resistance values of the temperature measurement sensor 11a and the protection heat source sensor 11b, and controls the electrical resistance of the temperature measurement sensor 11a and the protection heat source sensor 11b to measure the temperature. The sensor 11a and the protection heat source sensor 11b are configured to generate heat. Thereby, when the temperature is measured by the temperature measurement sensor 11a, the control means 13 can control the electrical resistance of the protective heat source sensor 11b so as to be equal to the electrical resistance of the temperature measurement sensor 11a. The control means 13 can control the electrical resistance of the temperature measuring sensor 11a so that the temperature measuring sensor 11a generates heat at a predetermined temperature.

Next, the operation will be described.
The temperature measuring apparatus 10 can measure the surface temperatures of various objects as follows using the temperature measuring sensor 11a and the protective heat source sensor 11b. That is, first, the temperature measuring sensor 11 a is brought into contact with the surface of the DUT 1. At this time, the control means 13 controls the electric resistance of the protective heat source sensor 11b to be equal to the electric resistance of the temperature measuring sensor 11a, so that the protective heat source sensor 11b is equal to the temperature of the temperature measuring sensor 11a. Causes fever. As a result, the temperature of the surface of the object to be measured 1 becomes equal to the temperatures of the temperature measuring sensor 11a and the protection heat source sensor 11b. From the heat to the temperature measuring sensor 11a. In this state, the temperature can be measured with high accuracy and high accuracy by measuring the temperature with the temperature measuring sensor 11a.

  In this way, the temperature measuring device 10 cancels out the heat flowing from the surface of the DUT 1 to the temperature measurement sensor 11a by providing the protection heat source sensor 11b as a non-stationary protection heat source for the temperature measurement sensor 11a. The temperature can be measured without changing the state of the DUT 1 by making the loss of heat as close to zero as possible. Thereby, the surface temperature of various objects can be measured with higher accuracy and accuracy regardless of the contact method.

  The temperature measuring device 10 measures the temperature with high accuracy and high accuracy by changing the electric resistance of the protective heat source sensor 11b and using the fact that the protective heat source sensor 11b generates heat at a temperature corresponding to the electric resistance. be able to. For this reason, it is possible to perform temperature measurement in consideration of heat transfer from the surface of the DUT 1 with a relatively simple configuration using only two thermistors without using a separate heater or the like.

  The temperature measuring device 10 can be applied not only to the measurement of the surface temperature, but also to the measurement of thermophysical properties and flow velocity with high accuracy and high accuracy, and non-invasive medical diagnosis. For example, the flow velocity can be measured by installing the temperature measuring device 10 in the flowing fluid. At this time, it has been difficult to accurately measure an accurate value in the past because of the influence of heat loss on the lead wire 14 and the like, but by using the temperature measuring device 10, the influence of heat loss is eliminated. In this case, it is possible to measure an accurate temperature change, and the flow velocity can be measured with high accuracy and high accuracy. Further, by using another temperature measuring device 10 separately, it becomes possible to measure the fluid temperature with higher accuracy and accuracy, and to measure the flow velocity with higher accuracy and accuracy. Thus, the temperature measuring device 10 can also be used as a highly accurate and highly accurate current meter.

[Temperature measurement experiment]
Using the temperature measuring device 10 shown in FIG. 1, the temperature was actually measured. The measurement object 1 was made of aluminum kept constant at 35 ° C., and measurement was performed in a laboratory where the room temperature was kept at 26 ° C. Temperature measurement was performed when the thermistor of the protection heat source sensor 11b as the protection heat source was enabled and disabled. The result is shown in FIG. As shown in FIG. 2, when the protective heat source sensor 11b is invalid, it is confirmed that the temperature is lowered by about 0.3 ° C. even after 30 seconds due to the influence of heat loss to the lead wire 14 and the tube 12 and the like. It was done. On the other hand, when the protective heat source sensor 11b is effective, after about 20 seconds have passed, the temperature accurately indicates 35 ° C., and it has been confirmed that the influence of heat loss can be eliminated.

  As shown in FIG. 2, when the protective heat source sensor 11b is valid, the temperature measuring device 10 can measure the temperature almost accurately in about 10 seconds, and can be used for a sufficient time (20 to 30 seconds). After the above), it has been confirmed that an accurate temperature can be measured with an error of 0.01 ° C. or less.

  FIG. 3 shows temperature responses of the temperature measurement sensor 11a and the protection heat source sensor 11b when the protection heat source sensor 11b is valid. As shown in FIG. 3, it was confirmed that the thermistor of the protection heat source sensor 11b shows a behavior that follows the response of the thermistor of the temperature measurement sensor 11a. Thus, by using the protective heat source sensor 11b, heat loss that occurs in the case of the DUT 1 having a temperature higher than room temperature can be minimized, and accurate surface temperature measurement can be performed. Recognize.

[Measurement of thermal conductivity]
The temperature measuring device 10 shown in FIG. 1 was used as a thermal conductivity measuring device, and the thermal conductivity was measured. As the object 1 to be measured, water at 35 ° C. (1 wt%) hardened with agar was used, and the thermal conductivity was measured by the thermal pulse decay method. In the measurement, first, the temperature measurement sensor 11a was brought into contact with the surface of the object 1 to be measured, and the temperature measurement sensor 11a was given a constant power for 5 seconds to generate heat at a predetermined temperature. At this time, the protection heat source sensor 11b also generates heat in the same manner as the temperature measurement sensor 11a. Thereafter, the temperature change of the surface of the DUT 1 was measured by the temperature measurement sensor 11a, and the thermal conductivity was calculated from the temperature decay after the heating. The measurement was repeated 10 times.

  The results of temperature measurement are shown in FIG. As shown in FIG. 4, it was confirmed that the measurement values of 10 times almost overlapped, the reproducibility was high, and the temperature could be measured with very high accuracy. The thermal conductivity calculated from Fig. 4 is 0.596 ± 0.0056 W / (m · K), which is in good agreement with the known thermal conductivity of about 0.60 W / (m · K). It was confirmed that

  Thus, according to the temperature measuring device 10 (thermal conductivity measuring device), the heating of the DUT 1 and the temperature measurement can be performed by one unit, and therefore the thermal response when the DUT 1 is heated. It can be said that the thermophysical properties of the DUT 1 can be measured with high accuracy and high accuracy. When performing the heat pulse attenuation method used this time, conventionally, a heat source such as a thermistor was embedded in the DUT 1 in consideration of heat loss to the lead wire 14 or the like, but a temperature measuring device (thermal conductivity) According to the measuring device 10, it is not necessary to consider heat loss or to embed a heat source, and it is possible to measure the thermal conductivity with high accuracy and high accuracy in a non-invasive manner.

[Application to early detection of malignant melanoma]
Malignant melanoma is known to have the highest mortality among skin diseases. However, if the tumor can be removed properly by surgery, the survival rate after five years will be close to 100%, so early detection and treatment are very important. Conventionally, the identification from Kuroko was performed based on the color and shape of the tumor using a magnifying glass commonly called Delmascopy, but the diagnosis rate varies greatly depending on the intuition and experience of the dermatologist. There is a need for quantitative diagnostic techniques.

  Since the temperature measuring device 10 can measure the temperature and thermophysical property of an object noninvasively and accurately, the temperature measuring device 10 measures the difference between the thermophysical property of healthy skin and the thermophysical property of malignant melanoma. Therefore, it is considered that early diagnosis of malignant melanoma can be performed. Therefore, whether or not early diagnosis of malignant melanoma is possible with the temperature measuring device 10 was verified using a two-dimensional axisymmetric heat conduction analysis.

  FIG. 5 shows a two-dimensional axisymmetric numerical calculation model used for verification. The thermistor of the temperature measuring sensor 11a of the temperature measuring device 10 is in contact with the upper left skin surface of this model. The model shown in FIG. 5 has a five-layer structure of epidermis, dermal papilla layer, dermal reticulate layer, fat layer, and muscle layer, and it is assumed that malignant melanoma 2 exists in the dermal papilla layer. In addition, in order to consider the effect of progression of malignant melanoma 2, as shown in FIG. 6, the size of the tumor is changed for each degree of progression (Early stage, Clark level 2, Clark level 3, Clark level 4), Model calculations were performed for each case.

  The model calculation was performed by the method described in Non-Patent Document 1. That is, in the calculation, first, steady calculation was performed when the third kind boundary condition was given to the skin surface, and the in vivo initial temperature distribution was determined. Thereafter, the temperature rise when the uniform heat generation amount is given to the temperature measurement sensor 11a of the temperature measurement device 10 in a pulsed manner for 5 seconds and the temperature decay for 5 seconds after the heating are calculated, and the apparent heat conduction is calculated from the information. The rate was determined.

  The result of the model calculation is shown in FIG. FIG. 7 also shows the calculation results for healthy skin without malignant melanoma 2 (when the volume of malignant melanoma is zero). As shown in FIG. 7, the larger the volume of malignant melanoma 2, the larger the apparent thermal conductivity, and it was confirmed that there is a positive correlation between the apparent thermal conductivity and the tumor volume. . It is known that as the volume of malignant melanoma 2 increases, the progression of the tumor advances and the risk increases, so by measuring the thermal conductivity of malignant melanoma 2 using the temperature measuring device 10, It is considered that malignant melanoma 2 can be diagnosed.

  The temperature measuring device according to the present invention can be used as a thermal conductivity measuring device in addition to measuring body temperature, surface temperature of a substance, and the like. It can also be used as an anemometer, anemometer, semiconductor inspection device, food quality control device, diagnosis device for diseases such as malignant melanoma, and the like.

DESCRIPTION OF SYMBOLS 1 Measured object 2 Malignant melanoma 10 Temperature measuring device 11a Sensor for temperature measurement 11b Protection heat source sensor 12 Tube 13 Control means 14 Lead wire

Claims (4)

Two identical heat generation temperature sensors configured to change a predetermined physical quantity according to temperature, measure temperature based on the value of the physical quantity, and generate heat at a corresponding temperature by changing the physical quantity;
Control means connected to each exothermic temperature sensor,
One exothermic temperature sensor is provided so that the temperature can be measured by contacting the surface of the object to be measured.
The other exothermic temperature sensor is provided close to or in contact with the one exothermic temperature sensor so that heat can be exchanged with the one exothermic temperature sensor,
The control means is provided so as to be able to control the physical quantity of the other exothermic temperature sensor so as to be equal to the physical quantity of the one exothermic temperature sensor when the temperature is measured by the one exothermic temperature sensor. A temperature measuring device characterized by The two exothermic temperature sensors are composed of a thermistor or a platinum resistance temperature detector,
The temperature measuring device according to claim 1, wherein the physical quantity includes an electrical resistance. A temperature measuring device according to claim 1 or 2,
The thermal conductivity measuring device, wherein the control means is provided so as to be able to control the physical quantity of the one exothermic temperature sensor so as to cause the one exothermic temperature sensor to generate heat at a predetermined temperature. The one exothermic temperature sensor of the thermal conductivity measuring device according to claim 3 is brought into contact with the surface of the object to be measured, and after the one exothermic temperature sensor is caused to generate heat at the predetermined temperature by the control means, A method of measuring thermal conductivity, wherein the temperature change of the surface of the object to be measured is measured with one exothermic temperature sensor.