JP2015078891A - Temperature prediction method and pyrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature prediction method in a normal state having small calculation load and which hardly receives affection of disturbance.SOLUTION: Provided is the temperature prediction method in a normal state comprising: a step for measuring temperature change on a temperature sensor; a step for determining time integration of temperature measured by the temperature sensor in a predetermined period; and a step for determining normal temperature which is temperature on the temperature sensor in the normal state on the basis of initial temperature which is temperature of the temperature sensor in initial time point in the predetermined period and the time integration.

Description

  The present invention relates to a temperature prediction method and a thermometer.

  When measuring the temperature, there is a demand to quickly know the temperature of the measurement object. However, in a general contact-type thermometer, after the probe is brought into contact with the object to be measured, the temperature of the probe is increased by the heat, and the measurement is performed after waiting for an equilibrium state or a steady state. It took a long time, about 5 to 10 minutes.

  Therefore, the temperature of the equilibrium state or steady state is predicted based on the temperature change of the probe in the unsteady state.

  For example, Patent Document 1 describes a high-speed accurate temperature measurement device that predicts the internal temperature of an object to be measured by mathematically solving a heat transfer equation in an unsteady state using a set of sensors. ing.

Japanese Patent No. 3935915

  However, an equilibrium state or steady state temperature prediction method that has been used so far, as represented by Patent Document 1, gives a heat conduction equation as a heat conduction model, and uses a measured value of a temperature sensor to calculate this. It is a technique to solve, and at least ternary simultaneous equations must be solved. For this reason, a device using such a method is required to have a considerable calculation processing capacity, and if an error occurs in the measurement value due to a disturbance such as a change in the contact state between the probe and the measurement object, the predicted value is Practical accuracy is low due to large fluctuations.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a steady-state temperature prediction method that has a small calculation load and is not easily affected by disturbance.

  The invention disclosed in the present application in order to solve the above problems has various aspects, and the outline of typical aspects of the aspects is as follows.

  (1) A step of sequentially measuring a temperature change in the temperature sensor, a step of obtaining a time integral of the temperature of the temperature sensor in a predetermined period, and an initial temperature that is the temperature of the temperature sensor at the start of the predetermined period And obtaining a steady temperature which is a temperature in the steady state of the temperature sensor based on the time integration.

  (2) In (1), the step of obtaining the steady temperature is a step of multiplying the time integral by a coefficient obtained in advance and adding the result to the initial temperature.

  (3) A thermometer that measures the temperature of an object to be measured by the temperature prediction method according to (1) or (2).

  (4) In (3), a thermometer comprising a measuring element having at least one temperature sensor, and a controller that measures a steady temperature of the temperature sensor as the temperature of the measurement object.

  (5) In (3), a thermometer comprising a measuring element having a plurality of temperature sensors and a controller for calculating an internal temperature of the measurement object based on steady temperatures of the plurality of temperature sensors.

  (6) The thermometer according to (5), wherein the measuring element includes at least two temperature sensor stacks including the two temperature sensors coupled with a heat insulating material interposed therebetween.

  According to the above aspect (1) or (2), when predicting the steady-state temperature, the calculation load can be reduced and the influence of disturbance can be reduced.

  According to the above aspect (3), it is possible to obtain a thermometer that can quickly measure the steady-state temperature with a small calculation load and is less susceptible to disturbance.

  According to the aspect (4) above, a thermometer can be obtained that quickly measures the equilibrium temperature when the object to be measured and the probe are in a thermal equilibrium state with a small calculation load and is less susceptible to disturbance. It is done.

  According to the above aspect (5) or (6), it is possible to obtain a thermometer that quickly measures the internal temperature of the measurement object with a small calculation load and is hardly affected by disturbance.

It is a figure explaining the temperature prediction method used as the foundation of the present invention. It is the graph which showed the change of temperature T of the temperature sensor at the time of making a temperature sensor contact the measuring object with respect to time. It is an external view of the thermometer which is one Embodiment of this invention. It is a cross-sectional schematic diagram by the IV-IV line of FIG. It is an external view of the back side of the thermometer which is one Embodiment of this invention. It is an external view of the front side of the thermometer which is one Embodiment of this invention. It is a cross-sectional schematic diagram by the VII-VII line of FIG. It is an expanded sectional view which shows the structure of a measuring element and a temperature sensor laminated body.

  Hereinafter, the temperature prediction method that is the basis of the present invention will be described.

As shown in FIG. 1, consider a case where a temperature sensor 2 serving as a measuring element is brought into contact with a measurement object 1 and the temperature of the measurement object 1 is measured from the output of the temperature sensor 2. At this time, the temperature of the measuring object 1 is T _B , the temperature of the temperature sensor 2 is T, the ambient temperature around the temperature sensor 2 is T _E (<T _B ), and the heat flow rate from the measuring object 1 to the temperature sensor is Q ₁ , the thermal resistance at that time is K ₁ , the thermal flow rate dissipated from the temperature sensor 2 to the outside is Q ₂ , the thermal resistance at that time is K _2, and the initial temperature T ₀ (<T _B )).

When the temperature sensor 2 is brought into contact with the measurement object 1, heat flows from the measurement object 1 into the temperature sensor 2, and the temperature of the temperature sensor 2 rises. At this time, the heat flow rate Q ₁ flowing into the temperature sensor 2 is

である。また、温度センサ２から流出する熱流速Ｑ_２は、

It is. Further, the heat flow rate Q ₂ flowing out from the temperature sensor ₂ is

ここで、Ｔが十分に上昇し、

Here, T rises sufficiently,

となると、Ｔの温度変化がなくなる。この状態を定常状態と呼び、このときのＴを定常温度Ｔ_Ｓとする。なお、この定常状態のうち、

Then, the temperature change of T disappears. This condition is called steady state, and the T at this time is constant temperature T _S. Of these steady states,

となる状態、すなわち、

That is,

の場合を特に、平衡状態と呼ぶ。

This case is called an equilibrium state.

The output of the temperature sensor 2 in the steady state indicates the temperature of the temperature sensor 2 in the steady state. The temperature of the measurement object 1 can be obtained by knowing the temperature of the temperature sensor 2 in the steady state by various methods. . However, since up to the temperature sensor 2 reaches a steady state requires a considerable extent the time, given that predicting the steady state temperature T _S from the change in the temperature T of the temperature sensor 2 before the temperature sensor 2 reaches a steady state.

FIG. 2 is a graph showing the change of the temperature T of the temperature sensor 2 with respect to time when the temperature sensor 2 is brought into contact with the measurement object 1. As shown in the figure, the temperature T gradually approaches the steady temperature T _S as time t elapses from the initial temperature T ₀ . Here, the difference between the initial temperature T ₀ and the steady temperature T _S is ΔT, an appropriate time t _C is determined, and the time integration S in the section 0 <t <t _C is determined.

としたときに、発明者は、ＳとΔＴとの間にはαを定数として、

The inventor assumes that α is a constant between S and ΔT,

なる関係が成り立つことを見出した。なお、時間積分Ｓは、図中示した部分の面積を示すことになる。

I found that the relationship The time integration S indicates the area of the portion shown in the figure.

If this relationship is used, the change in temperature T in the temperature sensor 2 is sequentially measured, and the time integral S for the temperature T in the period from the start time t = 0 to t = t _C is obtained, whereby the steady temperature T _S can be obtained by multiplying the time integration S by the coefficient α and adding it to the initial temperature T ₀ as follows.

  Here, the constant α is a value determined according to the properties of the temperature sensor 2 and the measurement object 1. Therefore, when the measurement object 1 to be measured by the temperature sensor 2 is determined, the value of the constant α can be experimentally obtained in advance.

  Here, the time integration S can be obtained simply by sequentially measuring changes in the temperature T in the temperature sensor 2 and adding the measurement results (in the case of rectangular approximation. Trapezoidal approximation, Simpson approximation, etc.) It is possible to use the approximation method in), and the calculation load is very low. Furthermore, since the numerical integration is not easily influenced by white noise superimposed on the measurement value of the temperature sensor 2, the measurement error is reduced.

The time t _C may be set to a time at which measurement noise is reduced and the accuracy of the value of the time integration S can be ensured in consideration of the measurement resolution, and the temperature sensor 2 actually reaches a steady state. It can be much shorter time. Therefore, temperature measurement using this temperature prediction method enables temperature measurement in an extremely short time.

  Then, the thermometer 100 which is one Embodiment of this invention is demonstrated with reference to FIG. 3, FIG.

  FIG. 3 is an external view of the thermometer 100. The thermometer 100 shown in the figure is a thermometer 100 that measures the temperature of an object to be measured using the above-described temperature prediction method, and the probe 103 having a temperature sensor is in thermal equilibrium with the object to be measured. The temperature of the temperature sensor is measured as the temperature of the measurement object.

  Since the steady temperature is equal to the temperature of the measurement object in the thermal equilibrium state, the thermometer 100 of the present embodiment measures the steady temperature as the temperature of the measurement object. The illustrated thermometer 100 is shown as an underarm or sublingual thermometer as an example. A probe 103 provided at the tip of the thermometer 100 is a metal probe, and a temperature sensor, which is a thermistor, is accommodated therein. Further, a display unit 105 such as a liquid crystal display device that displays measurement results is provided on the front surface of the body 104 of the thermometer 100, and a push button 106 for instructing the start of measurement is provided at the rear end.

  4 is a schematic cross-sectional view taken along line IV-IV in FIG. A temperature sensor 102, here a thermistor, is provided in the probe 103 so as to be thermally coupled to the probe 103, and is provided on the substrate 108 by an arbitrary wiring such as an FPC (Flexible Printed Circuit) 107 or the like. Connected to the controller 109. In addition to the display device 105, a button switch 110 that detects the operation of the push button 106 is connected to the substrate 108, and all these devices are controlled by the controller 109. Electric power is supplied from the battery 111 to the electronic components such as the controller 109. Here, the battery 111 is shown as a small button-type battery, but the shape and form thereof are not particularly limited. Further, the controller 109 may be any information processing device such as a so-called microcontroller, DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), etc., but it has performance necessary for temperature measurement, and is small and has low power consumption. And low cost is desirable.

In the thermometer 100 according to the present embodiment, the temperature measurement is started by inserting the probe 103 under the armpit or the tongue and pressing the push button 106 down. When the controller 109 detects that the push button 106 is pressed by a signal from the button switch 110, the controller 109 continuously measures the temperature of the temperature sensor 102 for a predetermined time at a constant period, and based on the result, the temperature prediction method described above is used. The steady temperature T _S of the temperature sensor 102 is predicted. And here the steady temperature T _S is the equilibrium temperature, is equal to the temperature of the measurement object, is displayed as a measurement result on the display unit 105. At this time, the user may be notified that the measurement is completed with sound or light by using a buzzer (not shown) or an LED (Light Emitting Diode).

  Then, the thermometer 200 which is another one Embodiment of this invention is demonstrated with reference to FIGS.

  The thermometer 200 shown in FIG. 5 and FIG. 6 is a thermometer 200 that measures the temperature of an object to be measured using the above-described temperature prediction method, and uses measuring elements 203a and 203b having temperature sensors as the object to be measured. The temperature of the measurement object is calculated and measured based on the temperature of the temperature sensor when the temperature sensor is brought into a steady state.

  FIG. 5 is an external view of the thermometer 200 on the back side, and FIG. 6 is an external view of the thermometer 200 on the front side. The thermometer 200 applies the measuring head 212 provided so as to protrude from the body 204 to the object to be measured, and contacts the measuring elements 203a and 203b, which are metal probes, with the object to be measured. It measures the deep temperature. Here, as an example, the measurement target is a living body, for example, a human body, and is a deep thermometer that measures the temperature inside the tissue by bringing the measuring elements 203a and 203b into contact with the skin such as the forehead.

  On the back surface of the body 204, a display unit 205 such as a liquid crystal display device for displaying the measurement results and a push button 206 for supporting the start of measurement are provided. In addition, a battery lid 213 is visible in front of the body 204.

  FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. Temperature sensor stacks 214a and 214b are attached to the back surfaces of the measuring elements 203a and 203b, respectively, so as to be thermally coupled. The temperature sensor laminates 214a and 214b are formed by connecting two temperature sensors, here thermistors, with a heat insulating material interposed therebetween. Therefore, in the illustrated example, four temperature sensors are provided. However, the number and arrangement of the temperature sensors may be appropriately changed according to the deep temperature measurement method.

  Each temperature sensor is connected to a controller 209 provided on the substrate 208 by an arbitrary wiring such as the FPC 207. The board 208 is also connected with a button switch 210 that detects the operation of the display device 205 and the push button 206, and all these devices are controlled by the controller 209. Electric power is supplied from the battery 211 to the electronic components such as the controller 209. In the illustrated example, the battery 211 is shown as an AAA type battery, but the shape and form are not particularly limited, as in the previous embodiment. The same applies to the point that the controller 209 may be any information processing apparatus.

  FIG. 8 is an enlarged cross-sectional view showing the structures of the measuring elements 203a and 203b and the temperature sensor stacked bodies 214a and 214b. As shown in detail in the figure, the temperature sensor laminate 214a is formed by sequentially laminating a temperature sensor 202a, a heat insulating material 215a, and a temperature sensor 202c from the measuring element 203a side, and the temperature sensor 202a is arranged on the measuring element 203a. On the other hand, the temperature sensor 202 c is exposed to the space inside the thermometer 200. Thereby, the heat flowing in from the probe 203a is transmitted to the temperature sensor 202a, then flows through the heat insulating material 215a to the temperature sensor 202c, and is dissipated to the outside air. The temperature sensor laminated body 214b has the same structure, and a temperature sensor 202b attached to the probe 203b, a heat insulating material 215b, and a temperature sensor 203d exposed to the space are laminated in this order. Here, the heat resistance values of the heat insulating material 215a and the heat insulating material 215b are different from each other, and the magnitude of the heat flux passing through the temperature sensor laminate 214a and the magnitude of the heat flux passing through the temperature sensor laminate 214b are It is supposed to be different.

The thermometer 200 calculates and measures the deep temperature of the measurement object from the steady temperatures of the temperature sensors 202a to 202d. Since this calculation method is known, the description of the derivation method is omitted. However, the obtained deep temperature is T _D , the steady temperature of the temperature sensor 202a is T _Sa , the steady temperature of the temperature sensor 202b is T _Sb , and the temperature sensor 202c If the steady temperature is T _Sc , the steady temperature of the temperature sensor 202d is T _Sd , and the ratio of the thermal resistance of the heat insulating material 215a and the heat insulating material 215b is K, it can be obtained as follows. Note that the value of K is obtained in advance by experiments or the like.

In the thermometer 200 according to this embodiment, the temperature measurement is started by bringing the measuring elements 203a and 203b into contact with the forehead, which is a measurement object, and pressing the push button 206 down. When the controller 209 detects the depression of the push button 206 based on a signal from the button switch 210, the controller 209 continuously measures the temperature of the temperature sensors 202a to 202d for a predetermined time at a constant period, and based on the result, the temperature prediction described above The steady-state temperatures T _{Sa to} T _Sd of the temperature sensors 202a to 202d are predicted by the method. Then, to calculate the core temperature T _D from the obtained value, displayed as a measurement result on the display unit 205. At this time, it is the same as in the previous embodiment that the user may be notified that the measurement has been completed with sound or light using a buzzer or LED (not shown).

In addition, when using the temperature sensor laminated bodies 214a and 214b as in the thermometer 200 according to the present embodiment, the time integrals of the temperature of each of the temperature sensors 202a to 202d are not necessarily obtained individually. Good. To describe the temperature sensor stack 214a as a representative, the amount of heat _{Q Ca} accumulated in the temperature sensor stack 202a is proportional to the integral of the difference between the temperature _{T c} of the temperature _{T a} and the temperature sensor 202c of the temperature sensor 202a. When the proportionality coefficient is ω, it is as follows.

If the temperature difference from the initial temperature T _0a of the temperature sensor 202a to the steady temperature T _Sa is ΔT _a , and the temperature difference from the initial temperature T _0b of the temperature sensor 202b to the steady temperature T _Sb is ΔT _b , the time t _Between the heat storage amount _QCa and ΔT _a and ΔT _{b in} the temperature sensor laminate 214a up to _C , the following relationship is established with α _a and α _b as constants.

From this relationship, ΔT _a and ΔT _b can be obtained from the time integration of the temperature difference between the temperature sensors 202a and 202c of the temperature sensor stacked body 214a in a predetermined period until time t _C , and thereby each steady temperature T _Sa and T _Sc can be predicted. The same applies to the temperature sensor laminate 214b. When this method is used, the number of time integrals that must be obtained is smaller than that described above.

  The specific configurations shown in the embodiments described above are shown as examples, and the invention disclosed in this specification is not limited to the configurations of these specific examples. Those skilled in the art may appropriately modify various modifications to the disclosed embodiments, for example, the shape, number, arrangement, etc. of each member or part thereof, and the technical scope of the invention disclosed in this specification is It should be understood to include such modifications.

  DESCRIPTION OF SYMBOLS 1 Measurement object, 2 Temperature sensor, 100 Thermometer, 102 Temperature sensor, 103 Measuring element, 104 Body, 105 Display part, 106 Push button, 107 FPC, 108 Board | substrate, 109 Controller, 110 Button switch, 111 Battery, 200 Temperature 202a, 202b, 202c, 202d temperature sensor, 203a, 203b probe, 204 body, 205 display, 206 push button, 207 FPC, 208 board, 209 controller, 210 button switch, 211 battery, 212 measuring head, 213 Battery lid, 214a, 214b Temperature sensor laminate, 215a, 215b Thermal insulation.

Claims (6)

Sequentially measuring temperature changes in the temperature sensor;
Obtaining a time integral of the temperature of the temperature sensor in a predetermined period;
Obtaining an initial temperature, which is the temperature of the temperature sensor at the start of the predetermined period, and a steady temperature, which is a temperature in a steady state of the temperature sensor, based on the time integration;
A steady state temperature prediction method comprising: The step of obtaining the steady temperature is a step of multiplying the time integral by a coefficient obtained in advance and adding to the initial temperature.
The temperature prediction method according to claim 1.   The thermometer which measures the temperature of a measurement object with the temperature prediction method of Claim 1 or 2. A probe having at least one temperature sensor;
The thermometer according to claim 3, further comprising a controller that measures a steady temperature of the temperature sensor as a temperature of the measurement object. A probe having a plurality of the temperature sensors;
The thermometer according to claim 3, further comprising a controller that calculates an internal temperature of the measurement object based on steady temperatures of the plurality of temperature sensors. The thermometer according to claim 5, wherein the measuring element has at least two sets of temperature sensor stacks including the two temperature sensors coupled with a heat insulating material interposed therebetween.

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