Temperature detection device and temperature detection method
The temperature detection device addresses accuracy and design limitations by using a vacuum container with a metal member and electrode system to measure temperature without a window, ensuring high precision and flexibility.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- NISSIN ELECTRIC CO LTD
- Filing Date
- 2025-01-16
- Publication Date
- 2026-07-29
AI Technical Summary
Existing temperature measurement devices face issues with reduced accuracy due to window contamination and limited design freedom due to the requirement of a vacuum chamber with a window that obstructs infrared ray passage.
A temperature detection device that utilizes a vacuum container, a metal member inside the container irradiated by electromagnetic waves, an electrode supplied with photoelectrons from the metal member, and a current measurement mechanism to detect temperature without a window, allowing high design freedom and accuracy.
The device achieves high temperature measurement accuracy and flexibility by eliminating the need for a window, reducing contamination risks and enhancing design possibilities.
Smart Images
Figure 2026122820000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a temperature detection device and a temperature detection method.
Background Art
[0002] Patent Document 1 discloses a temperature measurement device that calculates respective emissivities by changing the area ratio of two surfaces with different emissivities provided in a reference heat source, and corrects the radiation amount from the measured substance based on the calculated transmittance to calculate the true temperature.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the temperature measurement device disclosed in Patent Document 1, since a vacuum chamber provided with a window is required, there is a risk that the measurement accuracy of the temperature may be lowered due to window contamination and the influence of the window material.
[0005] In the temperature measurement device disclosed in Patent Document 1, a material that inhibits the passage of infrared rays cannot be used for the window, and a configuration for receiving and measuring the radiation from the measured substance outside the vacuum chamber is required, so the design freedom is low.
[0006] One aspect of the present disclosure aims to realize a temperature detection device or the like with high temperature measurement accuracy and high design freedom degree.
Means for Solving the Problems
[0007] A temperature detection device according to one aspect of the present disclosure comprises: a vacuum container for housing at least a portion of an object to be measured; a metal member located inside the vacuum container and irradiated with electromagnetic waves having a wavelength dependent on the temperature of the object to be measured, emitted from the object to be measured; an electrode located inside the vacuum container and supplied with photoelectrons emitted from the metal member by irradiation of the electromagnetic waves with the metal member; and a current measuring mechanism electrically connected to the electrode. [Effects of the Invention]
[0008] According to one aspect of this disclosure, it is possible to realize a temperature detection device, etc., that has high temperature measurement accuracy and a high degree of design flexibility. [Brief explanation of the drawing]
[0009] [Figure 1] This is a cross-sectional view showing the configuration of a temperature detection device according to Embodiment 1 of this disclosure. [Figure 2] This is a cross-sectional view showing the operating principle of a temperature detection device according to Embodiment 1 of this disclosure. [Figure 3] This is a flowchart showing the operation flow of the temperature detection device according to Embodiment 1 of this disclosure. [Figure 4] This table shows the work function, limiting frequency, and limiting wavelength for cesium and lithium, respectively. [Figure 5] This is a graph showing spectral radiance against wavelength. [Figure 6] This is an enlarged view of area 54 in Figure 5. [Figure 7] This demonstrates Planck's law. [Figure 8] This is a plan view showing an example of an electrode. [Figure 9] This is a cross-sectional view showing the operating principle of a temperature detection device according to Embodiment 2 of this disclosure. [Figure 10] This graph shows the voltage when the current measuring mechanism indicates a current value of 0A, relative to the temperature of the object being measured. [Modes for carrying out the invention]
[0010] A mode for implementing the present disclosure will be described. For convenience of explanation, members having the same functions as those described above may be given the same reference numerals, and the description thereof may not be repeated.
[0011] 〔Embodiment 1〕 FIG. 1 is a cross-sectional view showing the configuration of a temperature detection device 101 according to Embodiment 1 of the present disclosure. The temperature detection device 101 detects the temperature of the object to be measured 1. The temperature detection device 101 includes a vacuum container 2, a metal member 3, an electrode 4, a current measurement mechanism 5, a DC power source 51, and an insulator 52.
[0012] The vacuum container 2 houses at least a part of the object to be measured 1. It is preferable that the vacuum container 2 houses all of the object to be measured 1, but when it is difficult for the vacuum container 2 to house all of the object to be measured 1 due to problems such as the shape, size, and arrangement mode of the object to be measured 1, the vacuum container 2 may house a part of the object to be measured 1. When the vacuum container 2 houses a part of the object to be measured 1, the gap between the vacuum container 2 and the object to be measured 1 may be blocked by the insulator 52.
[0013] The metal member 3 is located inside the vacuum container 2. The metal member 3 is irradiated with an electromagnetic wave 6 having a wavelength that depends on the temperature of the object to be measured 1 and is radiated from the object to be measured 1. The electrode 4 is located inside the vacuum container 2. The electrode 4 is supplied with photoelectrons 7 emitted from the metal member 3 by the irradiation of the electromagnetic wave 6 on the metal member 3.
[0014] The current measurement mechanism 5 is electrically connected to the electrode 4. The current measurement mechanism 5 measures the value of the current flowing between the electrode 4 and a location with a known potential (e.g., ground 53 and earth). Examples of the current measurement mechanism 5 include an ammeter and a galvanometer. The DC power source 51 applies a voltage to the electrode 4.
[0015] FIG. 2 is a cross-sectional view showing the operating principle of the temperature detection device 101 according to Embodiment 1 of the present disclosure. When the metal member 3 is irradiated with an electromagnetic wave 6 having a wavelength shorter than the critical wavelength inherent to the metal member 3, the metal member 3 may emit photoelectrons 7. Thereby, a configuration in which the metal member 3 emits photoelectrons 7 can be easily realized.
[0016] FIG. 3 is a flowchart showing the operation flow of the temperature detection device 101 according to Embodiment 1 of the present disclosure. The operation flow of the temperature detection device 101, in other words, the temperature detection method according to Embodiment 1 of the present disclosure includes Steps S1 to S4.
[0017] In Step S1, at least a part of the object to be measured 1, the metal member 3, and the electrode 4 are arranged in the vacuum container 2. In Step S2, an electromagnetic wave 6 having a wavelength that depends on the temperature of the object to be measured 1 and is radiated from the object to be measured 是 irradiated onto the metal member 3. In Step S2, the object to be measured 1 may be heated to a high temperature by Joule heat or the like due to energization, and the electromagnetic wave 6 having a wavelength shorter than the critical wavelength (of the material) of the metal member 3 may be irradiated onto the metal member 3.
[0018] In Step S3, the photoelectrons 7 emitted from the metal member 3 due to the irradiation of the electromagnetic wave 6 onto the metal member 3 are supplied to the electrode 4. In Step S3, the metal member 3 emits photoelectrons 7 by the photoelectric effect, and the photoelectrons 7 may be incident on the electrode 4 located in the vicinity of the metal member 3. In Step S4, a current value is measured by a current measurement mechanism 5 electrically connected to the electrode 4. In Step S4, the value of the current flowing between the electrode 4 and the ground 53 may be measured by the current measurement mechanism 5 to detect the temperature rise of the object to be measured 1.
[0019] According to the temperature detection device 101, since a window is not required in the vacuum vessel 2, the risk of low temperature measurement accuracy can be reduced. According to the temperature detection device 101, since a window is not required in the vacuum vessel 2 (where materials that obstruct the passage of infrared rays cannot be used), there is a high degree of design freedom. The temperature detection device 101 is suitable for detecting the temperature of an object to be measured to the extent that it can detect abnormal heating, such as when the temperature of the object to be measured exceeds its melting point.
[0020] The material of the metal component 3 may be cesium, lithium, or a metal or alloy having a work function (limiting wavelength) suitable for the temperature to be detected. If the material of the metal component 3 is cesium, it is possible to detect that the temperature of the object 1 to be measured is approximately 700K or higher. If the material of the metal component 3 is lithium, it is possible to detect that the temperature of the object 1 to be measured is approximately 900K or higher.
[0021] Figure 4 is a table showing the work function, critical frequency, and critical wavelength for cesium and lithium, respectively. Figure 5 is a graph showing spectral radiance against wavelength. Figure 6 is a magnified view of range 54 in Figure 5. Figure 7 shows Planck's law.
[0022] The notation "(number α)E+(number β)" means (number α) × 10 raised to the power of (number β). For example, the notation "2E+04" means 2 × 10 4 This means that... In Figure 6, dotted lines 55 and 56 are shown, indicating the limiting wavelength of cesium (0.65 μm) and lithium (0.43 μm). The higher the temperature of the object under test 1, the more the rise of the spectral radiance in the object under test 1 shifts to the shorter wavelength side.
[0023] Let's consider the case where the material of metal component 3 is cesium. When the temperature of object 1 is 700K or lower, the spectral radiance of object 1 for the limiting wavelength of cesium is approximately 0 W / sr / m 3Therefore, theoretically, the metal component 3 does not emit photoelectrons 7, and photoelectrons 7 are not supplied to the electrode 4. When the temperature of the object under test 1 is, for example, 900K or higher, the spectral radiance of the object under test 1 for the limiting wavelength of cesium is approximately 2E+04W / sr / m 3 As a result, the metal component 3 emits photoelectrons 7, which are supplied to the electrode 4. Consequently, when the temperature of the object under test 1 is 700K or lower, the current value measured by the current measuring mechanism 5 is approximately 0A, while when the temperature of the object under test 1 is 900K or higher, the current value measured by the current measuring mechanism 5 is significantly different from 0A. If the material of the metal component 3 is cesium, it can be interpreted that the current measuring mechanism 5 can monitor whether the temperature of the object under test 1 is approximately 700K or higher.
[0024] Figure 8 is a plan view showing an example of the electrode 4. The electrode 4 may also be in a mesh shape. This reduces interference between the electrode 4 and the irradiation of electromagnetic waves 6 to the metal member 3, thereby reducing the risk of false detection of the temperature of the object to be measured 1.
[0025] The temperature detection device 101 may be capable of detecting that the temperature of the object under test 1 is abnormal when the absolute value of the current measured by the current measuring mechanism 5 exceeds a predetermined threshold. Detection of the abnormal temperature of the object under test 1 may be done by a person checking a needle or display that shows the current value measured by the current measuring mechanism 5, or by providing a mechanism that changes the behavior of the current measuring mechanism 5 when the absolute value of the current measured exceeds a predetermined threshold, and detecting the abnormality based on this change in behavior.
[0026] The potential of electrode 4 may be positive. For example, by applying a voltage to electrode 4 using a DC power supply 51 to make the potential of electrode 4 positive, the function of electrode 4 attracting photoelectrons 7 can be realized. Therefore, for example, when the distance between the metal member 3 and electrode 4 is large, the risk of leakage of photoelectrons 7 to electrode 4 can be reduced.
[0027] The temperature detection device 101 may detect that the temperature of the object 1 is abnormally high, or it may detect that the temperature of the object 1 is abnormally low. In other words, the temperature detection device 101 can be used in both of the following patterns (1) and (2).
[0028] (1) When the object to be measured 1 is maintained below a predetermined temperature (for example, 700K if the material of the metal member 3 is cesium, or for example, 900K if the material of the metal member 3 is lithium), abnormal heating that occurs when the object to be measured 1 exceeds the predetermined temperature is detected. For example, by detecting when a pipe (object to be measured 1) placed inside a vacuum container 2 exceeds its melting point, it can be used to prevent the pipe from melting.
[0029] (2) When the object to be measured 1 is maintained at a temperature above a predetermined temperature (for example, 700K if the material of the metal member 3 is cesium, or for example, 900K if the material of the metal member 3 is lithium), abnormal cooling that occurs when the object to be measured 1 falls below the predetermined temperature is detected. For example, in casting, it can be used to prevent the solidification of molten metal (object to be measured 1) placed in the vacuum container 2 by detecting when the molten metal falls below its melting point.
[0030] [Embodiment 2] Figure 9 is a cross-sectional view showing the operating principle of the temperature detection device 101 according to Embodiment 2 of this disclosure. Figure 10 is a graph showing the voltage when the current measuring mechanism 5 shows a current value of 0A with respect to the temperature of the object to be measured 1.
[0031] The relationship between the temperature of the object being measured 1 and the voltage applied to the electrode 4 when the current measured by the current measuring mechanism 5 becomes 0A may be known. This makes it possible to realize a high-precision temperature detection device 101.
[0032] Before actually detecting the temperature of the object 1 using the temperature detection device 101, it is possible to realize a high-precision temperature detection device 101 if the relationship between the temperature of the object 1 and the voltage applied to the electrode 4 when the current value measured by the current measurement mechanism 5 becomes 0A can be understood. An example of a method for understanding this relationship in advance is as follows.
[0033] While measuring the temperature of the object 1 (not shown) using a thermocouple or the like, a blocking voltage is applied to the electrode 4 using a DC power supply 51 so that the current measuring mechanism 5 shows a current value of 0A. The blocking voltage when the object 1 is at temperature T1 is denoted as V1, and the blocking voltage when the object 1 is at temperature T2 is denoted as V2. The horizontal axis of the graph in Figure 10 is formed based on temperatures T1 and T2, and the vertical axis of the graph in Figure 10 is formed based on blocking voltages V1 and V2 to complete the graph in Figure 10. In other words, the voltage when the current measuring mechanism 5 shows a current value of 0A is specifically the blocking voltage applied to the electrode 4 when the current value measured by the current measuring mechanism 5 becomes 0A. Thus, when detecting the temperature of the object 1 using the temperature detection device 101, the temperature of the object 1 can be determined if this blocking voltage is known.
[0034] The temperature detection device 101 operating according to the principle shown in Figure 2 detects the temperature of the object to be measured 1 by comparing it with a threshold value. On the other hand, the temperature detection device 101 operating according to the principle shown in Figure 9 can detect the actual temperature of the object to be measured 1. Therefore, the temperature detection device 101 operating according to the principle shown in Figure 9 can be considered a high-precision temperature detection device 101 compared to the temperature detection device 101 operating according to the principle shown in Figure 2.
[0035] 〔summary〕 A temperature detection device according to Embodiment 1 of the present disclosure comprises: a vacuum container for housing at least a portion of an object to be measured; a metal member located inside the vacuum container and irradiated with electromagnetic waves having a wavelength dependent on the temperature of the object to be measured, emitted from the object to be measured; an electrode located inside the vacuum container and supplied with photoelectrons emitted from the metal member by irradiation of the electromagnetic waves with the metal member; and a current measuring mechanism electrically connected to the electrode.
[0036] In the temperature detection device according to embodiment 2 of the present disclosure, in embodiment 1, the metal member emits photoelectrons when irradiated with electromagnetic waves having a wavelength shorter than the limiting wavelength inherent to the metal member.
[0037] In the temperature detection device according to embodiment 3 of the present disclosure, in embodiment 1 or 2, the material of the metal member is cesium, lithium, or a metal or alloy having a work function (limiting wavelength) suitable for the temperature to be detected.
[0038] In the temperature detection device according to embodiment 4 of this disclosure, the electrode is in a mesh shape in any of embodiments 1 to 3.
[0039] The temperature detection device according to embodiment 5 of the present disclosure is capable of detecting that the temperature of the object being measured is abnormal when the absolute value of the current measured by the current measuring mechanism exceeds a predetermined threshold, in any of embodiments 1 to 4.
[0040] A temperature detection method according to aspect 6 of the present disclosure involves placing at least a portion of an object to be measured, a metal member, and an electrode in a vacuum container, irradiating the metal member with electromagnetic waves having a wavelength dependent on the temperature of the object to be measured and emitted from the object to be measured, supplying photoelectrons emitted from the metal member by the irradiation of the metal member with electromagnetic waves to the electrode, and measuring the current value using a current measuring mechanism electrically connected to the electrode.
[0041] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. [Explanation of Symbols]
[0042] 1 Object to be measured 2 Vacuum container 3 Metal components 4 electrodes 5 Current measurement mechanism 6. Electromagnetic waves 7 Photoelectron 101 Temperature detection device
Claims
1. A vacuum container containing at least a portion of the object to be measured, A metal member located inside the vacuum container is irradiated with electromagnetic waves having a wavelength dependent on the temperature of the object to be measured, which are emitted from the object to be measured. An electrode located inside the vacuum container, to which photoelectrons emitted from the metal member by irradiation of the metal member with electromagnetic waves are supplied, A temperature detection device comprising a current measuring mechanism electrically connected to the aforementioned electrode.
2. The temperature detection device according to claim 1, wherein the metal member emits photoelectrons when irradiated with electromagnetic waves having a wavelength shorter than the limiting wavelength inherent to the metal member.
3. The temperature detection device according to claim 1 or 2, wherein the material of the metal member is cesium, lithium, or a metal or alloy having a work function suitable for the temperature to be detected.
4. The temperature detection device according to claim 1 or 2, wherein the electrode is in a mesh shape.
5. The temperature detection device according to claim 1 or 2, which can detect that the temperature of the object being measured is abnormal when the absolute value of the current measured by the current measuring mechanism exceeds a predetermined threshold.
6. At least a portion of the object to be measured, a metal component, and an electrode are placed inside a vacuum chamber. The electromagnetic waves emitted from the object to be measured, having a wavelength dependent on the temperature of the object to be measured, are irradiated onto the metal member. Photoelectrons emitted from the metal member by irradiation of the metal member with electromagnetic waves are supplied to the electrode. A temperature detection method that measures the current value using a current measuring mechanism electrically connected to the aforementioned electrode.