JP2016080608A - Temperature measurement device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure temperature more accurately using a fluorescence temperature sensor even in an environment in which dirt adheres to a fluorescent crystal.SOLUTION: A temperature signal creation part 121 outputs a temperature signal based on resistance change or the like on a correction temperature sensor 104, a change width detection part 122 detects change width in a set time, in the temperature signal output from the temperature signal creation part 121, and when the change width equal to or lower than the set value, is detected, a correction part 123 uses the temperature signal output from the temperature signal creation part 121 at this time, and executes temperature correction on a temperature signal creation part 116.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a temperature measuring device and a temperature measuring method using a fluorescent temperature sensor using a fluorescent material made of a crystal such as ruby.

  For the temperature measurement of the fluid, for example, a temperature sensor using a thermocouple and a resistance temperature detector is used. When the temperature measurement target is a corrosive gas or a corrosive solution, the above-described temperature sensor is housed in a protective tube to protect the temperature sensor from a corrosive environment. However, in such a configuration, since the temperature measurement is performed via the protective tube, the response of the temperature measurement is significantly slowed down.

  On the other hand, according to the fluorescence temperature sensor using a fluorescent material made of a crystal such as ruby, even in a corrosive environment, the ruby serving as the detection part has high corrosion resistance, so it is not accommodated in a protective tube. It becomes possible to use for temperature measurement (refer nonpatent literatures 1 and 2). For this reason, the response speed of the fluorescent temperature sensor is about one digit faster than the temperature sensor in which the resistance temperature detector is housed in the protective tube.

H. Aizawa et al., "Evaluation of the Fiber-Optic Thermometer Using Fluorescent Lifetime of Ruby", IEEJ Trans. SM, vol.123, no.6, pp.178-184,2003. Shizuichiro Kinugasa, Yasuyuki Kato, Norio Kikuchi, Yusei Yanagawa, “Development of Fluorescent Temperature Sensor”, azbil Technology Review, pp. 62-67, January 2012 issue.

  By the way, in the fluorescence temperature sensor, when dirt adheres to the surface of the phosphor crystal, the optical characteristics change and the measurement result shifts. In the configuration in which the phosphor crystal is in contact with the fluid whose temperature is to be measured, dirt is likely to adhere to the contact surface. In general, the fluorescent temperature sensor is periodically removed and cleaned, and re-calibration (temperature correction) is performed after cleaning.

  However, during the period until the periodic temperature correction is performed, the shift state of the measurement result cannot be grasped, and if it is shifted, the process is affected. In addition, the periodic cleaning / temperature correction as described above interrupts the process and cannot be performed frequently. Thus, in the temperature measurement using a fluorescence temperature sensor, there exists a problem that the case where an exact temperature measurement cannot be performed occurs.

  The present invention has been made to solve the above-described problems, and enables temperature measurement more accurately using a fluorescent temperature sensor even in an environment where dirt is attached to a phosphor crystal. The purpose is to do.

  The temperature measuring device according to the present invention includes a protective tube, a phosphor crystal having a contact region in contact with an object to be measured, fixed to one end of the protective tube, and inserted from the other end of the protective tube, into the phosphor crystal. An optical fiber that guides excitation light and fluorescence from the phosphor crystal, a non-optical correction temperature sensor for temperature correction disposed inside the protective tube, and temperature measurement by fluorescence from the phosphor crystal Temperature change value detection unit for detecting a change width at a set time of a temperature measurement value obtained by a value or a correction temperature sensor, and a correction temperature sensor by detecting a change width equal to or less than a set value by the change width detection unit And a correction unit that corrects the temperature measurement value due to the fluorescence from the phosphor crystal with the temperature measurement value obtained by the above.

  The temperature measuring method according to the present invention includes a protective tube, a phosphor crystal having a contact region in contact with a measurement object, and fixed to one end of the protective tube, and is inserted from the other end of the protective tube. Temperature correction method for fluorescent temperature sensor, comprising optical fiber for guiding excitation light to crystal and fluorescence from phosphor crystal, and non-optical correction temperature sensor for temperature correction arranged inside protective tube A change width detection step for detecting a change width in a set time of a temperature measurement value obtained by fluorescence from the phosphor crystal or a temperature measurement value obtained by a correction temperature sensor, and a change less than the set value A correction step of correcting the temperature measurement value by the fluorescence from the phosphor crystal with the temperature measurement value obtained by the correction temperature sensor by detecting the width.

  As described above, according to the present invention, it is possible to obtain an excellent effect that temperature measurement can be performed more accurately using a fluorescent temperature sensor even in an environment where dirt is adhered to the phosphor crystal.

FIG. 1 is a configuration diagram showing a configuration of a temperature measurement device according to Embodiment 1 of the present invention. FIG. 2 is a flowchart illustrating the temperature measurement method according to Embodiment 1 of the present invention. FIG. 3 is a characteristic diagram showing the responsiveness (a) of temperature measurement by a fluorescent temperature sensor and the responsiveness (b) of temperature measurement by a resistance temperature detector. FIG. 4 is a configuration diagram showing the configuration of the temperature measurement device according to Embodiment 2 of the present invention. FIG. 5 is a flowchart for explaining a temperature measurement method according to Embodiment 2 of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
First, Embodiment 1 of the present invention will be described. FIG. 1 is a configuration diagram showing a configuration of a temperature measurement device according to Embodiment 1 of the present invention. This apparatus first includes a protective tube 101, a phosphor crystal 102 having a contact region in contact with a measurement object and fixed to one end of the protective tube 101, and a phosphor crystal inserted from the other end of the protective tube 101. And an optical fiber 103 that guides excitation light to the light 102 and fluorescence from the phosphor crystal 102. Further, a non-optical correction temperature sensor 104 for temperature correction is disposed inside the protective tube 101. The correction temperature sensor 104 is composed of, for example, a thermocouple or a resistance temperature detector.

The phosphor crystal 102 is, for example, ruby. Ruby is a crystal in which chromium ions (Cr ³⁺ ) are added to an aluminum oxide single crystal. As is well known, fluorescence is emitted centering on a wavelength of 694.3 nm by, for example, irradiation with excitation light having a center wavelength of 550 nm. The lifetime of this fluorescence varies with temperature.

  First, the excitation light emitted from the light emitting diode 112 controlled by the excitation light control unit 111, reflected by the dichroic filter 113 and passed through the condenser lens 114 is guided through the optical fiber 103 and reaches the phosphor crystal 102. To do. The phosphor crystal 102 irradiated with the excitation light in this way emits fluorescence. This fluorescence is guided through the optical fiber 103 and collected by the condenser lens 114, passes through the dichroic filter 113, is received by the photodiode 115, is photoelectrically converted, and is output as a detection signal. The output detection signal is converted into a temperature signal (temperature measurement value) by the temperature signal generator 116.

  In addition to the above-described configuration, the first embodiment includes a temperature signal generation unit 121, a change width detection unit 122, and a correction unit 123. The temperature signal generation unit 121 outputs a temperature signal based on a resistance change in the correction temperature sensor 104 or the like.

  The change width detector 122 detects the change width in the set time of the temperature measurement value obtained by the correction temperature sensor 104. In the first embodiment, the change width within the set time in the temperature signal output from the temperature signal generation unit 121 is detected. For example, the change width of the temperature signal in 5 seconds is detected.

  The correction unit 123 corrects the temperature measurement value due to the fluorescence from the phosphor crystal 102 with the temperature measurement value obtained by the correction temperature sensor 104 by detecting the change width equal to or less than the set value by the change width detection unit 122. In the first embodiment, when a change width equal to or smaller than the set value is detected, temperature correction in the temperature signal generation unit 116 is performed with the temperature signal output from the temperature signal generation unit 121 at this time.

  Next, the temperature measurement method in Embodiment 1 is demonstrated using the flowchart of FIG. First, in step S201, when the set correction execution time is reached, in step S202, the change width detection unit 122 calculates the change width at the set time of the temperature measurement value obtained by the correction temperature sensor 104. To detect. For example, the change width of the temperature signal in 5 seconds is detected.

  Next, in step S203, the correction unit 123 determines whether or not the detected temperature signal change width is smaller than a set value. When the detected temperature signal change width is larger than the set value (n in step S203), the change width in the set time of the temperature measurement value obtained by the correction temperature sensor 104 is detected again. On the other hand, when the detected temperature signal variation width is smaller than the set value (y in step S203), the process proceeds to step S204, and the temperature signal output from the temperature signal generation unit 121 at this time is the temperature signal generation unit 116. Perform temperature correction at. Thereafter, the above operation is continued until an operation stop instruction is accepted (step S205).

  The correction temperature sensor 104 is housed in the protective tube 101 and does not touch the object to be measured. Therefore, even in the case of a corrosive fluid, a resistance value change (in the case of a resistance temperature detector) due to corrosion of elements and lead wires. The temperature reading does not shift. However, the correction temperature sensor 104 using a resistance temperature detector or the like is completely housed in the protective tube, and therefore has a slower response speed than the fluorescent temperature sensor. For example, as shown in FIG. 3, the response (b) of the correction temperature sensor using the resistance temperature detector made of platinum housed in the protector is slower than the response (a) of the fluorescence temperature sensor.

  On the other hand, the process temperature to be measured does not always remain constant but changes. In the process of changing the temperature in this way, the response speed is different as described above. Therefore, the temperature measurement value by the correction temperature sensor using the resistance temperature detector and the temperature measurement value by the fluorescence temperature sensor are: Will be different. Therefore, if temperature correction is performed in the temperature signal generation unit 116 with the temperature measurement value obtained by the correction temperature sensor 104 at the set time, an erroneous temperature measurement is performed.

  Here, as is apparent from FIG. 3, there is almost no difference in responsiveness, for example, at a location where the change in responsiveness for 5 seconds is as small as about 5, and the temperature measured by the resistance temperature detector is normal (clean). The temperature measurement value obtained by the fluorescent temperature sensor in the above state can be substantially in agreement. Therefore, when the change in the temperature measurement value by the correction temperature sensor 104 becomes smaller than a set value (for example, 1 ° C.) by the change width detection unit 122, the temperature measurement value by the correction temperature sensor 104 becomes the phosphor crystal 102. It can be set equal to the temperature measurement value by the temperature signal generation unit 116 in a state where no dirt is attached. Based on these findings, in the first embodiment, when the change in the temperature measurement value by the correction temperature sensor 104 becomes smaller than a set value (for example, 1 ° C.), the temperature measurement value by the correction temperature sensor 104 is used. The temperature correction in the temperature signal generation unit 116 is performed.

[Embodiment 2]
Next, a second embodiment of the present invention will be described. FIG. 4 is a configuration diagram showing the configuration of the temperature measurement device according to Embodiment 2 of the present invention. This apparatus first includes a protective tube 101, a phosphor crystal 102 having a contact region in contact with a measurement object and fixed to one end of the protective tube 101, and a phosphor crystal inserted from the other end of the protective tube 101. And an optical fiber 103 that guides excitation light to the light 102 and fluorescence from the phosphor crystal 102. Further, a non-optical correction temperature sensor 104 for temperature correction is disposed inside the protective tube 101. The correction temperature sensor 104 is composed of, for example, a thermocouple or a resistance temperature detector.

The phosphor crystal 102 is, for example, ruby. Ruby is a crystal in which chromium ions (Cr ³⁺ ) are added to an aluminum oxide single crystal. As is well known, fluorescence is emitted centering on a wavelength of 694.3 nm by, for example, irradiation with excitation light having a center wavelength of 550 nm. The lifetime of this fluorescence varies with temperature.

  First, the excitation light emitted from the light emitting diode 112 controlled by the excitation light control unit 111, reflected by the dichroic filter 113 and passed through the condenser lens 114 is guided through the optical fiber 103 and reaches the phosphor crystal 102. To do. The phosphor crystal 102 irradiated with the excitation light in this way emits fluorescence. This fluorescence is guided through the optical fiber 103 and collected by the condenser lens 114, passes through the dichroic filter 113, is received by the photodiode 115, is photoelectrically converted, and is output as a detection signal. The output detection signal is converted into a temperature signal (temperature measurement value) by the temperature signal generator 116.

  In the second embodiment, a temperature signal generation unit 121, a change width detection unit 422, and a correction unit 423 are provided. The temperature signal generation unit 121 is the same as in the first embodiment described above, and outputs a temperature signal based on a resistance change in the correction temperature sensor 104 or the like.

  The change width detector 422 detects a temperature change per unit time in a set time interval of the temperature measurement value obtained by fluorescence from the phosphor crystal. In the second embodiment, the temperature change (change width) per unit time is detected within the set time in the temperature signal output from the temperature signal generation unit 116. For example, the change width per unit time of the temperature measurement obtained by fluorescence from the phosphor crystal is continuously detected for the set 30 seconds.

  The correction unit 423 is a temperature measurement value obtained by the correction temperature sensor 104 based on the detection of a change width equal to or less than a set value (for example, 0.1 ° C.) by the change width detection unit 422, and is based on fluorescence from the phosphor crystal 102. Correct the temperature reading. In the second embodiment, when a change width equal to or smaller than the set value is detected, temperature correction in the temperature signal generation unit 116 is performed using the temperature signal output from the temperature signal generation unit 121 at this time.

  Next, the temperature measurement method in Embodiment 2 is demonstrated using the flowchart of FIG. First, when the set correction execution time is reached in step S501, in step S502, the change width detecting unit 422 sets the set time (for example, 30 seconds) of the temperature measurement value by the fluorescence from the phosphor crystal 102. The temperature change width at is detected.

  Next, in step S503, the correction unit 423 determines whether the change width per unit time of the detected temperature measurement value is smaller than the set value. If the detected temperature signal change width is larger than the set value (step S503: n), the process returns to step S502.

  On the other hand, when the detected temperature signal change width is smaller than the set value (y in step S503), the process proceeds to step S504, and the temperature signal output from the temperature signal generation unit 121 at this time is the temperature signal generation unit 116. Perform temperature correction at. Thereafter, the above operation is continued until an instruction to stop the operation is received (step S505).

  The correction temperature sensor 104 is housed in the protective tube 101 and does not touch the object to be measured. Therefore, even in the case of a corrosive fluid, a resistance value change (in the case of a resistance temperature detector) due to corrosion of elements and lead wires. The temperature measurement value will not shift. However, the correction temperature sensor 104 using a resistance temperature detector or the like is completely housed in the protective tube, and therefore has a slower response speed than the fluorescent temperature sensor. For example, as described with reference to FIG. 3, the response (b) of the correction temperature sensor using the resistance temperature detector made of platinum contained in the protector is compared with the response (a) of the fluorescence temperature sensor. slow.

  On the other hand, the process temperature to be measured does not always remain constant but changes. In the process of changing the temperature in this way, the response speed is different as described above. Therefore, the temperature measurement value by the correction temperature sensor using the resistance temperature detector and the temperature measurement value by the fluorescence temperature sensor are: Will be different. Therefore, if temperature correction is performed in the temperature signal generation unit 116 with the temperature measurement value obtained by the correction temperature sensor 104 at the set time, an erroneous temperature measurement is performed.

  Here, as is clear from FIG. 3, for example, if the temperature of the measurement target is constant for 30 seconds, the difference in the reached temperature due to the difference in responsiveness is almost eliminated, and the temperature measurement value by the resistance thermometer and normal It can be assumed that the measured temperature value by the fluorescent temperature sensor in a (clean) state substantially coincides. Therefore, when the change width of the temperature measurement value by the fluorescence temperature sensor becomes smaller than a set value (for example, 0.1 ° C.) within a predetermined time by the change width detection unit 422, the temperature of the measurement target is sufficiently stabilized. Therefore, the temperature measurement value by the correction temperature sensor 104 can be made equal to the temperature measurement value by the temperature signal generation unit 116 in a state where the phosphor crystal 102 is not contaminated.

  Based on these findings, in the second embodiment, the temperature sensor for correction is used when the change width of the temperature measurement value by the fluorescence temperature sensor becomes smaller than a set value (for example, 0.1 ° C.) within a predetermined time. The temperature correction by the temperature signal generation unit 116 is performed using the temperature measurement value obtained by 104.

  In addition, when the change width detected within the predetermined time does not become the set value or less, it can be considered that the temperature of the measurement target is changing. As described above, since the response speed of the correction temperature sensor 104 is slow, the temperature measurement value of the correction temperature sensor 104 when the temperature of the measurement target is changing cannot be a correct measurement result. Therefore, when the change width of the temperature measurement value due to the fluorescence from the phosphor crystal 102 does not become smaller than the set value during a predetermined time (for example, 30 seconds), it is assumed that the temperature of the measurement object changes in this state. The temperature was not corrected.

  As described above, in the present invention, the change width in the set time of the temperature measurement value obtained by the fluorescence from the phosphor crystal or the temperature measurement value obtained by the correction temperature sensor may be equal to or less than the set value. When detected, the temperature measurement value obtained by the temperature sensor for correction is used to correct the temperature measurement value due to fluorescence from the phosphor crystal, so even in an environment where dirt adheres to the phosphor crystal, The temperature can be measured more accurately using the fluorescent temperature sensor.

The present invention is not limited to the embodiment described above, and many modifications and combinations can be implemented by those having ordinary knowledge in the art within the technical idea of the present invention. It is obvious. For example, the phosphor crystal is not limited to ruby, and may be composed of crystals such as MgAl ₂ O ₄ , YAlO ₃ , yttrium, aluminum, and garnet.

  Also, the temperature measurement value due to the fluorescence from the phosphor crystal is constantly monitored, and the time during which the temperature measurement value change width is less than the set value (for example, 0.1 ° C.) is measured, and this time becomes 30 seconds or more. If (continues for 30 seconds or more), the correction may be performed based on the measurement result of the correction temperature sensor.

  DESCRIPTION OF SYMBOLS 101 ... Protective tube, 102 ... Phosphor crystal, 103 ... Optical fiber, 104 ... Correction temperature sensor, 111 ... Excitation light control part, 112 ... Light emitting diode, 113 ... Dichroic filter, 114 ... Condensing lens, 115 ... Photodiode 116, a temperature signal generation unit, 121, a temperature signal generation unit, 122, a change width detection unit, and 123, a correction unit.

Claims (2)

A protective tube,
A phosphor crystal fixed to one end of the protective tube with a contact region in contact with the measurement object;
An optical fiber that is inserted from the other end of the protective tube and guides excitation light to the phosphor crystal and fluorescence from the phosphor crystal;
A temperature correction method for a fluorescent temperature sensor, comprising: a non-optical correction temperature sensor for temperature correction disposed inside the protective tube,
A change width detection step of detecting a change width in a set time of a temperature measurement value by fluorescence from the phosphor crystal or a temperature measurement value obtained by the correction temperature sensor;
And a correction step of correcting a temperature measurement value obtained by fluorescence from the phosphor crystal with a temperature measurement value obtained by the correction temperature sensor by detecting the change width equal to or less than a set value. Measuring method. A protective tube,
A phosphor crystal fixed to one end of the protective tube with a contact region in contact with the measurement object;
An optical fiber that is inserted from the other end of the protective tube and guides excitation light to the phosphor crystal and fluorescence from the phosphor crystal;
A non-optical correction temperature sensor for temperature correction disposed inside the protective tube;
A change width detector for detecting a change width in a set time of a temperature measurement value by fluorescence from the phosphor crystal or a temperature measurement value obtained by the correction temperature sensor;
A correction unit that corrects a temperature measurement value due to fluorescence from the phosphor crystal with a temperature measurement value obtained by the correction temperature sensor by detecting the change width equal to or less than a set value by the change width detection unit. A temperature measuring device characterized by that.

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