A temperature measurement device

Abstract

The present invention discloses a temperature measurement device, belonging to the technical field of temperature detection, comprising: a collection unit, a conduction unit, an optical fiber probe and a temperature sensing probe; the collection unit includes a control unit, a laser light source and an optical electrolytic demodulator; the laser light source is connected to the optical fiber probe; the optical fiber probe is connected to the optical electrolytic demodulator; the optical fiber probe includes a collimator and a partial mirror; the temperature sensing probe includes a temperature sensing element and a total mirror, the total mirror is connected to the temperature sensing element, and the total mirror is disposed opposite to the partial mirror; wherein, the collimator is used to adjust the incident light beam into a collimated light beam vertically incident on the partial mirror, and the partial mirror decomposes the incident light beam into a first light beam and a second light beam; the first light beam returns, and the second light beam is incident on the total mirror through the partial mirror, and the second light beam returns after being reflected by the total mirror; the distance between the partial mirror and the total mirror can be measured through the first light beam and the second light beam, and then the external temperature value can be calculated.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature detection, and particularly relates to a temperature measurement device. Background Art

[0002] Temperature measurement is widely used in modern industrial and agricultural production, scientific research, national defense construction and other fields. Due to the fact that fiber optic temperature sensors do not generate sparks, they have good safety characteristics in flammable, explosive and other dangerous places and are widely favored.

[0003] However, for existing fiber optic temperature sensors using optical fiber as the temperature sensing element, because the optical fiber itself is relatively fragile, especially at higher temperatures, the optical fiber without the coating protection will embrittle when contacting with air, so its temperature measurement range is greatly limited;

[0004] For existing fiber optic temperature sensors using metal as the temperature sensing element, due to the characteristics of the optical path built and the limitation of the way of using metal to sense temperature, it cannot achieve both high sensitivity and small occupied space.

[0005] At the same time, in the actual application process, a single model of temperature sensor cannot meet the requirements of different temperature measurement accuracies and ranges in different usage scenarios. Summary of the Invention

[0006] The purpose of the embodiments of the present invention is to provide a temperature measurement device, which can solve the technical problems that existing temperature detection devices often use a single model of temperature sensor, the temperature measurement range is greatly limited, the sensitivity is low, and it is difficult to meet different application scenarios.

[0007] To solve the above technical problems, the present invention is implemented as follows:

[0008] The embodiments of the present invention provide a temperature measurement device, including: a collection unit, a conduction unit, an optical fiber probe and a temperature sensing probe;

[0009] The collection unit includes a control unit, a laser light source and an optical demodulator, and both the laser light source and the optical demodulator are connected to the control unit;

[0010] The laser light source is connected to the optical fiber probe through the conduction unit;

[0011] The optical fiber probe is connected to the optical demodulator through the conduction unit;

[0012] The optical fiber probe includes a collimator and a partial reflector, and the collimator is connected to the partial reflector;

[0013] The temperature sensing probe includes a temperature sensing element and a total reflector, the total reflector is connected to the temperature sensing element, and the total reflector is disposed opposite to the partial reflector;

[0014] Among them, the collimator is used to adjust the incident light beam emitted from the laser light source into a collimated light beam that is vertically incident on the partial mirror, and the partial mirror decomposes the incident light beam into a first light beam and a second light beam;

[0015] The first light beam returns, and the second light beam is incident on the total mirror through the partial mirror. After being reflected by the total mirror, the second light beam returns;

[0016] When the external temperature changes, the temperature-sensitive element deforms to drive the total mirror to displace, thereby changing the distance between the partial mirror and the total mirror. The distance between the partial mirror and the total mirror can be measured through the first light beam and the second light beam, and the external temperature value is calculated based on the distance between the partial mirror and the total mirror.

[0017] In the embodiment of the present invention, when the external temperature changes, the temperature-sensitive element deforms to drive the total mirror to displace, thereby changing the distance between the partial mirror and the total mirror. The distance between the partial mirror and the total mirror can be measured through the first light beam and the second light beam, and the external temperature value is calculated based on the distance between the partial mirror and the total mirror. The temperature measurement device provided by the present invention has a wide temperature measurement range and high sensitivity, and can meet different application scenarios. At the same time, it also has the characteristics of no spark, high precision, small space occupied by the probe, low cost, and high adaptability, meeting most of the requirements for temperature measurement in daily life and industrial production. Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of a temperature measurement device provided by an embodiment of the present invention;

[0019] Figure 2 is a schematic structural diagram of another temperature measurement device provided by an embodiment of the present invention.

[0020] The realization, functional characteristics, and advantages of the object of the present invention will be further described in conjunction with the embodiments and with reference to the drawings. Detailed Embodiments

[0021] To make the object, technical solution, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] The terms "first", "second", "third", "fourth", etc. (if any) in the description, claims and above-mentioned drawings of the present disclosure are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein.

[0023] It should be understood that in the present disclosure, "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0024] The temperature measurement device provided by the embodiments of the present invention will be described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0025] Refer to Figure 1 , which shows a schematic structural diagram of a temperature measurement device provided by an embodiment of the present invention.

[0026] Refer to Figure 2 , which shows a schematic structural diagram of another temperature measurement device provided by an embodiment of the present invention.

[0027] A temperature measurement device provided by an embodiment of the present invention includes: an acquisition unit 10, a conduction unit 20, an optical fiber probe 30, and a temperature sensing probe 40.

[0028] The acquisition unit 10 includes a control unit 101, a laser light source 102, and an optical demodulator 103. Both the laser light source 102 and the optical demodulator 103 are connected to the control unit 101.

[0029] Among them, the frequency of the laser beam emitted by the laser light source 102 is tunable.

[0030] Among them, the control unit 101 can control the frequency of the laser beam emitted by the laser light source 102. At the same time, the control unit 101 can also control the optical demodulator 103 to extract information from the interference light.

[0031] The laser light source 102 is connected to the optical fiber probe 30 through the conduction unit 20.

[0032] The optical fiber probe 30 is connected to the optical demodulator 103 through the conduction unit 20.

[0033] The optical fiber probe 30 includes a collimator 301 and a partial reflector 302. The collimator 301 is connected to the partial reflector 302.

[0034] The temperature sensing probe 40 includes a temperature sensing element 401 and a total reflection mirror 402. The total reflection mirror 402 is connected to the temperature sensing element 401, and the total reflection mirror 402 is disposed opposite to the partial reflection mirror 302.

[0035] Among them, the collimator 301 is used to adjust the incident light beam emitted from the laser light source 102 into a collimated light beam that is vertically incident on the partial reflection mirror 302. The partial reflection mirror 302 decomposes the incident light beam into a first light beam and a second light beam; the first light beam returns, and the second light beam is incident on the total reflection mirror 402 through the partial reflection mirror 302, and the second light beam returns after being reflected by the total reflection mirror 402.

[0036] When the external temperature remains unchanged, the temperature sensing element 401 remains unchanged, and the distance value between the partial reflection mirror 302 and the total reflection mirror 402 remains unchanged; when the temperature changes, the temperature sensing element reflects the temperature change in its deformation.

[0037] When the external temperature changes, the temperature sensing element 401 deforms to drive the total reflection mirror 402 to displace to change the distance between the partial reflection mirror 302 and the total reflection mirror 402. The distance between the partial reflection mirror 302 and the total reflection mirror 402 can be measured by the first light beam and the second light beam, and the external temperature value is calculated according to the distance between the partial reflection mirror 302 and the total reflection mirror 402.

[0038] In the embodiment of the present invention, when the external temperature changes, the temperature sensing element 401 deforms to drive the total reflection mirror 402 to displace to change the distance between the partial reflection mirror 302 and the total reflection mirror 402. The distance between the partial reflection mirror 302 and the total reflection mirror 402 can be measured by the first light beam and the second light beam, and the external temperature value is calculated according to the distance between the partial reflection mirror 302 and the total reflection mirror 402. The temperature testing device provided by the present invention has a wide temperature measurement range and high sensitivity, and can meet different application scenarios. At the same time, it also has the characteristics of no spark, high precision, small space occupied by the probe, low cost, and high adaptability, meeting most of the requirements for temperature measurement in daily life and industrial production.

[0039] In a possible implementation manner, the conduction unit 20 includes a circulator 201 and a single-mode optical fiber 202; the output end of the laser light source 102 is connected to the first end of the circulator 201 through the single-mode optical fiber 202; the input end of the optical demodulator 103 is connected to the second end of the circulator 201 through the single-mode optical fiber 202; the third end of the circulator 201 is connected to the optical fiber probe 30 through the single-mode optical fiber 202.

[0040] Among them, on the one hand, the circulator 201 can conduct the laser light beam emitted from the laser light source 102 to the optical fiber probe 30, and on the other hand, it can conduct the interference light returned from the optical fiber probe 30 to the optical demodulator 103.

[0041] In a possible implementation, the temperature sensing probe 40 is detachably connected to the optical fiber probe 30. In the face of different temperature measurement requirements, the corresponding temperature sensing probe 40 can be replaced to meet the temperature measurement needs of different application scenarios.

[0042] Furthermore, the temperature sensing probe 40 and the optical fiber probe 30 can be detachably connected by means of a threaded connection.

[0043] Furthermore, in order to facilitate temperature measurement and docking with the temperature sensing probe 400, the optical fiber probe 30 further includes a fixed terminal 304 and a housing 305. The housing 305 is provided with a cavity. When the temperature sensing probe 40 is connected to the optical fiber probe 30, a partial mirror 302 is fixedly provided at one end of the housing 305. The total mirror 402 can move within the cavity. At this time, an interference cavity is formed between the partial mirror 302 and the total mirror 402, and the distance between the two mirrors is called the cavity length.

[0044] In a possible implementation, the temperature sensing probe 40 further includes a metal housing 403; a receiving space is provided inside the metal housing 403; the temperature sensing element 401 is at least partially disposed in the receiving space; the inner end of the temperature sensing element 401 is fixedly provided in the metal housing 403, and the outer end of the temperature sensing element 401 is movable; the total mirror 402 is fixedly provided at the outer end of the temperature sensing element 401.

[0045] Among them, during operation, the temperature sensing probe 40 is placed in the measurement environment. The metal housing 403 first contacts the temperature field. The metal housing 403 transfers the temperature in the environment field to the temperature sensing element 401 and protects the deformation of the temperature sensing element 401 from factors other than temperature.

[0046] In a possible implementation, the temperature sensing element 401 is formed by helically winding a bimetallic strip. The bimetallic strip includes a first metal strip 4011 and a second metal strip 4012 arranged in a laminated manner, and the thermal expansion coefficients of the first metal strip and the second metal strip are different.

[0047] Furthermore, the outer first metal strip 4011 is a metal with a high coefficient of thermal expansion and serves as the active layer, and the inner second metal strip 4012 is a metal with a low coefficient of thermal expansion and serves as the passive layer. When the temperature rises, the outer end of the temperature sensing element 401 moves forward; when the temperature drops, the outer end of the temperature sensing element 401 moves backward.

[0048] It should be noted that in the process of researching temperature measurement technology, the inventor found that: a bimetallic strip formed by welding two metals with different coefficients of thermal expansion together, namely the first metal strip 4011 and the second metal strip 4012, is helically wound to form a temperature-sensitive element 401. The inner end is fixed and the outer end is movable. When affected by temperature, due to the different coefficients of thermal expansion of the two metal materials, the first metal strip 4011 and the second metal strip 4012 restrict each other. Therefore, the deformation of the temperature-sensitive element 401 in the radial direction is smaller compared to a single metal, and the deformation of the outer end is more compared to a single metal. When the temperature changes, the deformation of the outer end of the temperature-sensitive element is mainly in a two-dimensional plane, and for the same temperature-sensitive element 401, its position deformation at a certain temperature is unique. By measuring the amount of deformation in a certain dimension, the corresponding relationship between the amount of deformation and temperature can be found. Therefore, conversely, by measuring its amount of deformation, the corresponding temperature value can be found to complete temperature measurement.

[0049] Furthermore, temperature-sensitive elements formed by helically winding bimetallic strips of the same model in different ways have different amounts of deformation when affected by temperature. According to this characteristic, various styles of temperature-sensitive elements can be prepared to meet different temperature measurement requirements.

[0050] At the same time, the dimensional parameters and winding methods of the helical winding of the bimetallic strip can be determined according to different working environments.

[0051] In a possible implementation manner, the displacement generated by the temperature-sensitive element 401 due to the change in the external temperature to drive the total reflection mirror 402 is:

[0052] Formula 1

[0053] Wherein, is the displacement, is the effective temperature-sensitive length of the temperature-sensitive element, is the effective coefficient of thermal expansion of the temperature-sensitive element, is the temperature change.

[0054] In a possible implementation manner, the center line of the partial reflection mirror 302 is aligned with the center line of the total reflection mirror 402. The first light beam reflected back by the partial reflection mirror 302 and the second light beam reflected back by the total reflection mirror 402 form interference light, and the optical demodulator 103 can extract the distance information between the partial reflection mirror 302 and the total reflection mirror 402 from the interference light.

[0055] It should be noted that the first light beam and the second light beam satisfy the interference conditions of the same frequency, a constant phase difference, and the same vibration direction. Therefore, when the first light beam meets the second light beam, the two will form interference light. The interference light contains the optical path difference information of the two parts of light, that is, the distance information between the two mirrors. By using certain photoelectric conversion and demodulation methods, the distance information can be extracted.

[0056] Furthermore, the interference light intensity can be expressed as:

[0057] where and are the light intensities of the first part of light and the second part of light respectively, is the optical path difference, is the instantaneous frequency of the laser output by the laser light source, is the speed of light. It can be seen from the formula that when the optical path difference remains unchanged and the laser frequency output by the laser light source 102 changes linearly with time, the interference light intensity is a cosine function of the laser frequency. By analyzing this function, the optical path difference can be obtained:

[0058] where f is the interference light intensity signal frequency, is the laser light source frequency scanning range, is the laser light source frequency scanning time. Among them and are known.

[0059] In a possible implementation manner, since d = L / 2, the photoelectric demodulator 103 calculates the distance between the partial mirror 302 and the total mirror 402 according to Formula 2:

[0060] where d is the distance between the two mirrors, f is the interference light intensity signal frequency, is the laser light source frequency scanning range, is the laser light source frequency scanning time.

[0061] In a possible implementation manner, the control unit 101 obtains the temperature value according to Formula 3:

[0062] where T is the current temperature value, T 0 is the temperature value before the temperature change, is the difference between the interference light intensity signal frequencies after and before the temperature change, is the effective temperature sensing length of the temperature sensing element, is the effective thermal expansion coefficient of the temperature sensing element.

[0063] In a possible implementation manner, the optical fiber probe 30 further includes a copper tube 303; both the collimator 301 and the partial mirror 302 are fixedly connected to the copper tube 303 so that the positions between the collimator 301 and the partial mirror 302 are kept unchanged.

[0064] The above are only the embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and changes can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A temperature measurement device, characterized in that, it includes: a collection unit, a conduction unit, an optical fiber probe and a temperature sensing probe; the collection unit includes a control unit, a laser light source and an optical demodulator, and both the laser light source and the optical demodulator are connected to the control unit; the laser light source is connected to the optical fiber probe through the conduction unit; the optical fiber probe is connected to the optical demodulator through the conduction unit; the optical fiber probe includes a collimator and a partial mirror, and the collimator is connected to the partial mirror; the temperature sensing probe includes a temperature sensing element and a total mirror, the total mirror is connected to the temperature sensing element, and the total mirror is disposed opposite to the partial mirror; wherein, the collimator is used to adjust the incident light beam emitted from the laser light source into a collimated light beam perpendicularly incident on the partial mirror, and the partial mirror decomposes the incident light beam into a first light beam and a second light beam; the first light beam returns, the second light beam is incident on the total mirror through the partial mirror, and the second light beam returns after being reflected by the total mirror; when the external temperature changes, the temperature sensing element deforms to drive the total mirror to generate a displacement to change the distance between the partial mirror and the total mirror, and the distance between the partial mirror and the total mirror can be measured through the first light beam and the second light beam, and the external temperature value is calculated according to the distance between the partial mirror and the total mirror.

2. The temperature measurement device according to claim 1, characterized in that, the conduction unit includes a circulator and a single-mode optical fiber; the output end of the laser light source is connected to the first end of the circulator through the single-mode optical fiber; the input end of the optical demodulator is connected to the second end of the circulator through the single-mode optical fiber; the third end of the circulator is connected to the optical fiber probe through the single-mode optical fiber.

3. The temperature measurement device according to claim 1, characterized in that, the temperature sensing probe is detachably connected to the optical fiber probe, and the corresponding temperature sensing probe can be replaced in the case of facing different temperature measurement requirements.

4. The temperature measurement device according to claim 1, characterized in that, the temperature sensing probe further includes a metal shell; a receiving space is arranged inside the metal shell; at least part of the temperature sensing element is arranged in the receiving space; the inner end of the temperature sensing element is fixedly arranged on the metal shell, and the outer end of the temperature sensing element is movable; the total mirror is fixedly arranged at the outer end of the temperature sensing element.

5. The temperature measurement device according to claim 1, characterized in that, the temperature sensing element is formed by helically winding a bimetallic strip, the bimetallic strip includes a first metal strip and a second metal strip arranged in a stacked manner, and the thermal expansion coefficients of the first metal strip and the second metal strip are different.

6. The temperature measurement device according to claim 1, characterized in that, the displacement generated by the temperature sensing element due to the change of the external temperature to drive the total mirror is: Wherein, is the displacement amount, is the effective temperature sensing length of the temperature sensing element, is the effective thermal expansion coefficient of the temperature sensing element, is the temperature change amount.

7. The temperature measurement device according to claim 1, characterized in that, The center lines of the partial mirror and the total mirror are aligned. The first light beam reflected back by the partial mirror and the second light beam reflected back by the total mirror form interference light, and the optical demodulator can extract the distance information between the partial mirror and the total mirror from the interference light.

8. The temperature measurement device according to claim 7, wherein, the optical demodulator calculates the distance between the partial mirror and the total mirror according to Formula 2: Among them, is the distance between the two reflecting mirrors, is the frequency of the interference light intensity signal, is the frequency scanning range of the laser light source, is the frequency scanning time of the laser light source.

9. The temperature measurement device according to claim 8, wherein, the control unit obtains the temperature value according to Formula 3: Among them, is the current temperature value, is the temperature value before the temperature change, is the difference between the interference light intensity signal frequencies after and before the temperature change, is the effective temperature sensing length of the temperature sensing element, is the effective thermal expansion coefficient of the temperature sensing element.

10. The temperature measurement device according to claim 1, wherein, the optical fiber probe further includes a copper tube; both the collimator and the partial mirror are fixedly connected to the copper tube.

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