An optical fiber temperature measurement system

Abstract

The present invention provides an optical fiber temperature measurement system, comprising a temperature measurement host A, a temperature measurement host B, and a reference optical fiber A and a temperature measurement optical fiber which are sequentially connected in series between the temperature measurement host A and the temperature measurement host B. By arranging a temperature measurement host at each end of the temperature measurement optical fiber, when any point of the temperature measurement optical fiber is broken, the temperature of the temperature measurement optical fiber behind the break point can still be measured, or when any temperature measurement host fails, the other temperature measurement host can continue to measure the temperature through the temperature measurement optical fiber, thereby ensuring that the temperature measurement protection function of the protected object is not interrupted; in addition, by arranging a reference optical fiber at each end of the temperature measurement optical fiber, the temperature calibration coefficient of the temperature measurement system can be adjusted at multiple points. Compared with the prior art that can only adjust the temperature calibration coefficient at a single point, the problem of low temperature measurement accuracy caused by the long use length of the temperature measurement optical fiber and serious attenuation of the tail end signal is greatly reduced, thereby improving the temperature measurement accuracy of the optical fiber temperature measurement system.

Description

Technical Field

[0001] The invention belongs to the technical field of fire detection, and relates to an optical fiber temperature measurement system, in particular to a high-reliability and high-precision optical fiber temperature measurement system. Background Art

[0002] The prior art optical fiber temperature measurement system comprises a temperature measurement host and a reference optical fiber and a temperature measurement optical fiber connected thereto in sequence; wherein the temperature measurement host comprises a signal processing unit, a pulse laser source unit, a wavelength division multiplexer, a photoelectric detector and a temperature measurement element; the signal processing unit is respectively: electrically connected to the pulse laser source unit, electrically connected to the photoelectric detector in sequence, connected to the wavelength division multiplexer optical fiber, and electrically connected to the temperature measurement element; the reference optical fiber is then connected to the wavelength division multiplexer and the pulse laser source unit optical fiber in sequence; its working principle is: the signal processing unit controls the pulse laser source unit to emit a pulse laser, and through the wavelength placed on the optical path The light enters the temperature measuring optical fiber after the wavelength division multiplexer (whose function is to combine light signals of different wavelengths into one beam when emitting light and transmit it along a single optical fiber; and to output light signals of different wavelengths separately when receiving light); as the temperature of the temperature measuring optical fiber changes, the light characteristics such as the frequency of light scattered or reflected in the core of the temperature measuring optical fiber will change accordingly; when the light scattered or reflected in the core of the temperature measuring optical fiber is transmitted in reverse to the wavelength division multiplexer, the wavelength division multiplexer transmits the light signal to be detected to the photoelectric detector for demodulation into an electrical signal, and then the signal processing unit collects and processes the data and displays the temperature data curve. The temperature measuring optical fiber and reference optical fiber adopt fiber grating type or fully distributed temperature measuring optical fiber.

[0003] In the existing optical fiber temperature measurement system, the reference optical fiber (which is a whole optical fiber with the temperature measurement optical fiber) and the temperature measurement element (such as a platinum electrode, a thermocouple) are coiled in the temperature measurement host. The temperature calibration method is as follows: on the one hand, the signal processing unit measures the temperature at the reference optical fiber according to the aforementioned principle, and on the other hand, reads the temperature at the reference optical fiber measured by the temperature measurement element. By comparing their temperature difference, the temperature calibration coefficient of the optical fiber temperature measurement system is adjusted to make the optical fiber temperature measurement system display a more accurate temperature.

[0004] However, the above-mentioned temperature measurement optical fiber is usually longer than 10 kilometers, which will cause the optical signal intensity to decay more obviously as the temperature measurement optical fiber is longer, and the distribution error of the temperature measurement curve will increase as the distance from the signal processor increases, especially at the tail end of the temperature measurement optical fiber; in addition, once a break occurs somewhere in the temperature measurement optical fiber, the optical path after the breakpoint will be interrupted, thus losing the temperature measurement function. These problems have seriously limited the application of temperature measurement optical fiber in long-distance temperature measurement and protection of important facilities. Summary of the invention

[0005] Based on the above problems, the purpose of the present invention is to provide a high-reliability and high-precision optical fiber temperature measurement system; including a temperature measurement host A, a temperature measurement host B, and a reference optical fiber A and a temperature measurement optical fiber which are sequentially connected in series between the temperature measurement host A and the temperature measurement host B; wherein the temperature measurement host A is mainly composed of a signal processing unit A, a pulse laser source unit A, a wavelength division multiplexer A, a photodetector A and a temperature measurement element A; the signal processing unit A is respectively: electrically connected to the pulse laser source unit A, electrically connected to the photodetector A in turn, optically connected to the wavelength division multiplexer A, and electrically connected to the temperature measurement element A; the reference optical fiber A is then optically connected to the wavelength division multiplexer A and the pulse laser source unit A in turn; the reference optical fiber A is coiled around the temperature measurement host A. and the temperature measuring element A is arranged therein; the temperature measuring host B is mainly composed of a signal processing unit B, a pulse laser source unit B, a wavelength division multiplexer B and a photoelectric detector B; the signal processing unit B is respectively: electrically connected to the pulse laser source unit B, which is in turn electrically connected to the photoelectric detector B and optically connected to the wavelength division multiplexer B; the reference optical fiber B is then in turn connected to the wavelength division multiplexer B and the pulse laser source unit B; the temperature measuring host A and the temperature measuring host B are in a master-slave operation relationship with each other.

[0006] Preferably, the temperature measuring optical fiber and the temperature measuring host B are also connected in series with a reference optical fiber B, and the temperature measuring host B also includes a temperature measuring element B; the signal processing unit B is electrically connected to the temperature measuring element B; the reference optical fiber B is coiled in the temperature measuring host B, and the temperature measuring element B is arranged thereat.

[0007] Preferably, the temperature measuring host A and the temperature measuring host B exchange messages within a predetermined time through the temperature measuring optical fiber, and the messages at least include the communication heartbeat of the temperature measuring host A or B, whether the temperature measurement function of the temperature measuring host A or B is faulty, the temperature measurement start / stop signal of the temperature measuring host A or B, and the actual temperature at the reference optical fiber A or B measured by the temperature measuring element A or B in the temperature measuring host A or B.

[0008] Preferably, the communication heartbeat of the temperature measuring host A or B is to send a message to the other party of the interconnection at regular intervals as agreed in the communication protocol, and judge whether the communication link between the two parties of the interconnection has been disconnected based on the response of the other party.

[0009] Preferably, the temperature measuring element A or B is a platinum electrode or a thermocouple temperature measuring element.

[0010] The present invention also provides another optical fiber temperature measurement system, comprising a temperature measurement host A' which is respectively connected in series with a reference optical fiber A and a temperature measurement optical fiber, wherein the temperature measurement host A' comprises a signal processing unit A', a temperature measurement element A, a wavelength division multiplexer A and a photoelectric detector A thereof, an optical switch and a pulse laser source unit A thereof, and a wavelength division multiplexer B and a photoelectric detector B thereof; the signal processing unit A' is respectively: electrically connected to the temperature measurement element A provided at the reference optical fiber A, electrically connected to the photoelectric detector A and the optical fiber of the wavelength division multiplexer A in turn, electrically connected to the pulse laser source unit A and the optical fiber of the optical switch in turn, electrically connected to the optical switch, and electrically connected to the photoelectric detector B and the optical fiber of the wavelength division multiplexer B in turn.

[0011] Preferably, the reference optical fiber A, wavelength division multiplexer A, optical switch, and wavelength division multiplexer B optical fibers are sequentially connected in series at both ends of the temperature measurement optical fiber to form a ring-shaped temperature measurement optical fiber loop.

[0012] Preferably, the annular temperature measurement optical fiber loop is further connected in series with a reference optical fiber B, and the temperature measurement host A' further comprises a temperature measurement element B disposed at the reference optical fiber B and electrically connected to the signal processing unit A'.

[0013] Preferably, the temperature measuring element A or B is a platinum electrode or a thermocouple temperature measuring element.

[0014] Preferably, the optical switch is a single-channel or dual-channel optical switch.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0016] 1. High reliability: Since a temperature measuring host is set at each end of the temperature measuring optical fiber, when any point of the temperature measuring optical fiber is broken, the temperature of the temperature measuring optical fiber behind the break point can still be measured, or when any temperature measuring host fails, the other temperature measuring host can continue to measure the temperature through the temperature measuring optical fiber, thereby ensuring that the temperature measurement protection function of the protected object is not interrupted; 2. High precision: By setting a reference optical fiber at each end of the temperature measuring optical fiber, the temperature calibration coefficient of the temperature measuring system can be adjusted at multiple points. Compared with the existing technology that can only adjust the temperature calibration coefficient at a single point, the problem of low temperature measurement accuracy caused by the long length of the temperature measuring optical fiber and severe signal attenuation at the tail end is greatly reduced, thereby improving the accuracy of the temperature measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structural principle of a temperature measurement optical fiber system provided in Example 1; Figure 2 This is a schematic diagram of the structural principle of a temperature measurement optical fiber system provided in Example 2.

[0018] Unified description of the numbers in the accompanying drawings: 1. Temperature measuring host A; 2. Temperature measuring optical fiber; 3. Optical switch; 4. Signal processing unit A; 5. Pulse laser source unit A; 6. Wavelength division multiplexer A; 7. Photoelectric detector A; 8. Reference optical fiber A; 9. Temperature measuring element A; 1′, temperature measuring host B; 4′, signal processing unit B; 5′, pulse laser source unit B; 6′, wavelength division multiplexer B; 7′, photoelectric detector B; 8′, reference optical fiber B; 9′, temperature measuring element B; 11. Temperature measuring host A′; 14. Signal processing unit A′. DETAILED DESCRIPTION

[0019] A high-reliability and high-precision optical fiber temperature measurement system provided by the present invention is described in detail below in conjunction with the accompanying drawings and embodiments. Embodiment 1

[0020] This embodiment provides a high-reliability and high-precision optical fiber temperature measurement system, such as Figure 1 As shown, it includes a temperature measuring host A1, a temperature measuring host B1′, and a reference optical fiber A8, a temperature measuring optical fiber 2, and a reference optical fiber B8′ which are sequentially connected in series between the temperature measuring host A1 and the temperature measuring host B1′; wherein the temperature measuring host A1 is mainly composed of a signal processing unit A4, a pulse laser source unit A5, a wavelength division multiplexer A6, a photodetector A7, and a temperature measuring element A9; the signal processing unit A4 is respectively: electrically connected to the pulse laser source unit A5, electrically connected to the photodetector A7, optically connected to the wavelength division multiplexer A6, and electrically connected to the temperature measuring element A9; the reference optical fiber A8 is then sequentially connected to the wavelength division multiplexer A6 and the pulse laser source unit A5 optical fiber; the reference optical fiber A8 is coiled in the temperature measuring host A1, and the temperature measuring element A9 is arranged thereon; the temperature measuring host B1′ is mainly composed of a signal processing unit B4′, a pulse laser source unit B5′, a wavelength division multiplexer B6, and a photodetector A7 ... reference optical fiber A8 is coiled in the temperature measuring host A1, and the temperature measuring element A9 is arranged thereon; the temperature measuring host B1′ is mainly composed of a signal processing unit B4′, a pulse laser source unit B5′, a wavelength division multiplexer B6, and a photodetector A7; the reference The temperature measuring host A1 and the temperature measuring host B1′ are composed of a photoelectric detector B6′, a photoelectric detector B7′ and a temperature measuring element B9′; the signal processing unit B4′ is respectively: electrically connected to the pulse laser source unit B5′, which is in turn electrically connected to the photoelectric detector B7′, optically connected to the wavelength division multiplexer B6′, and electrically connected to the temperature measuring element B9′; the reference optical fiber B8′ is then sequentially connected to the wavelength division multiplexer B6′ and the pulse laser source unit B5′; the reference optical fiber B8′ is coiled in the temperature measuring host B1′, and the temperature measuring element B9′ is arranged thereon; the temperature measuring host A1 and the temperature measuring host B1′ are in a master-slave operation relationship with each other.

[0021] Here’s how it works: The temperature measuring host A 1 and the temperature measuring host B 1′ maintain communication through the temperature measuring optical fiber 2 in the following manner: at the transmitting end (temperature measuring host A 1 or temperature measuring host B 1′), the signal processing unit modulates the electrical signal onto the pulsed laser emitted by the pulsed laser source unit, so that the intensity, frequency or phase of the light changes with the electrical signal, and then sends the optical signal out through the temperature measuring optical fiber 2; at the receiving end (temperature measuring host B 1′ or temperature measuring host A 1), the wavelength division multiplexer separates optical signals of different wavelengths, and then the photoelectric detector converts the received optical signal back into an electrical signal, and restores the original information after demodulation, which is then processed by its signal processing unit. The temperature measuring host A1, as a communication host, actively sends an electrical signal (i.e., a message) to the temperature measuring host B1' in each communication cycle. The message contains at least the following information: the communication heartbeat of the temperature measuring host A1, whether the temperature measuring function of the temperature measuring host A1 is faulty, the temperature measuring start / stop signal of the temperature measuring host A1, and the actual temperature at the reference optical fiber A8 measured by the temperature measuring element A9 in the temperature measuring host A1. After receiving the communication message from the temperature measuring host A1, the temperature measuring slave B1', as a communication slave, will reply with a message containing at least the following information: the communication heartbeat of the temperature measuring host B1', whether the temperature measuring function of the temperature measuring host B1' is faulty, the temperature measuring start / stop signal of the temperature measuring host B1', and the actual temperature at the reference optical fiber B8' measured by the temperature measuring element B9' in the temperature measuring host B1'. The communication heartbeat is to send a message to the other party of the interconnection at a predetermined time as agreed in the communication protocol, and judge whether the communication link between the two interconnected parties has been disconnected by the other party's reply.

[0022] When the temperature measurement host and the temperature measurement optical fiber are installed on site, the system starts to run self-test after power is turned on. Under normal circumstances, the self-test working state of the temperature measurement host A 1 is normal, and it will send the above message to inform the temperature measurement host B 1′ that it is ready to start emitting pulse laser temperature measurement. When the temperature measurement host B 1′ receives the communication heartbeat and temperature measurement function failure information of the temperature measurement host A 1, it still maintains its temperature measurement stop state unchanged (to prevent the reverse pulse lasers with the same characteristics emitted by the master and slave machines from interfering in the temperature measurement optical fiber 2 and affecting the temperature measurement function. This is because the pulse laser source units of the master and slave machines are usually the same, which meets the conditions of pulse laser interference), and replies with the communication heartbeat, temperature measurement function failure, temperature measurement function stop state and the actual temperature information at the reference optical fiber B 8′ measured by the temperature measurement element B 9′ therein. After receiving the above feedback message, the temperature measuring host A1 starts to implement temperature measurement: the signal processing unit A4 inside the temperature measuring host A1 controls the pulse laser source unit A5 to emit pulse laser, and the pulse laser enters the temperature measuring optical fiber after passing through the wavelength division multiplexer and the reference optical fiber. Then, the temperature measuring host A1 wavelength division multiplexer, photoelectric detector, and signal processing unit are used to detect and calculate the uncalibrated measured temperature value of each point on the entire temperature measuring optical fiber (the specific temperature measurement process is the existing fiber grating type or fully distributed optical fiber temperature measurement principle, which will not be repeated here). When the temperature measurement host A 1 is finished, the temperature measurement host A 1 will send a message to the temperature measurement host B 1′ to notify the temperature measurement host A 1 that the temperature measurement has stopped. After receiving the message, the temperature measurement host B 1′ is ready to start emitting pulse laser temperature measurement, and reply to the temperature measurement host A 1 with messages such as communication heartbeat, temperature measurement function failure, and temperature measurement function start status, and then start temperature measurement (the temperature measurement process is the same as the working principle of the temperature measurement optical fiber of the temperature measurement host A 1, which will not be repeated here), and send the measured temperature data of each point back to the temperature measurement host A 1 for processing. When the temperature measurement host B 1′ is finished, it will send a message to the temperature measurement host A 1 to notify it that the temperature measurement of the temperature measurement host B 1′ has stopped. After receiving the message, the temperature measurement host A 1 is ready to start the next temperature measurement cycle, and it will repeat itself.

[0023] In the case of abnormal optical fiber temperature measurement system, the processing method is as follows: 1) When the temperature measurement host A 1 or the temperature measurement host B 1' reports a temperature measurement function failure, the other party that receives the message enters the temperature measurement state, and the mutual redundant backup can greatly improve the reliability of the optical fiber temperature measurement system; 2) When the temperature measuring optical fiber is broken, the temperature measuring host A1 can compare the calibrated length of the temperature measuring optical fiber after construction with the measured length of the temperature measuring optical fiber to confirm the breakage of the temperature measuring optical fiber and the location of the break. At the same time, if the temperature measuring host B1′ does not receive any message from the temperature measuring host A1 within the set time, it will start the temperature measurement, that is, pulse laser temperature measurement is emitted from both ends of the temperature measuring optical fiber, so that the temperature of the protected object can continue to be measured, avoiding the problem in the prior art that after the temperature measuring optical fiber is broken, the temperature of the area behind the breakpoint cannot be measured.

[0024] 3) When the temperature measuring optical fiber has local sharp bends, external force squeezing, etc., which causes the optical signal to be significantly attenuated and affects the temperature measurement accuracy, this system can also actively identify it: the temperature measuring host A1 and the temperature measuring extension B1' communicate using the temperature measuring optical fiber. During temperature measurement, there is also laser emission and reception in the temperature measuring optical fiber. Therefore, the power attenuation loss of the emitted light and the received light can be directly measured, thereby judging whether there are manufacturing or installation defects in the temperature measuring optical fiber 2, that is, the problem of obvious attenuation of the optical signal caused by local sharp bends, external force squeezing, etc. of the temperature measuring optical fiber.

[0025] 4) When the temperature measuring host A1 or B1′ does not receive the communication heartbeat of the temperature measuring host B1′ or A1 within multiple consecutive set communication cycles, the temperature measuring host A1 or the temperature measuring host B1′ believes that the temperature measuring optical fiber 2 has been disconnected in the middle or the temperature measuring host at the other end is not powered on or cannot complete the temperature measuring optical fiber communication function. Then the temperature measuring hosts A1 and B1′ both start their own temperature measurement programs until the communication heartbeat of the temperature measuring host at the other end is restored, and compare the deviation between the temperature measurement of the temperature measuring optical fiber and the temperature measurement element directly measuring the temperature at the reference optical fiber to determine whether pulse laser interference has occurred to affect the temperature measurement result, and whether adjustments need to be made: If the temperature measuring hosts A1 and B1 1′ both start their own temperature measurement program without causing interference with the pulsed laser in the temperature measuring optical fiber 2, such as the temperature measuring optical fiber 2 being broken or any pulsed laser source unit being damaged, then the temperature of the protected object can continue to be measured as described in (2) above; if interference with the pulsed laser in the temperature measuring optical fiber 2 is caused, such as communication abnormality caused by damage to the communication function of the signal processing unit, then the temperature at the reference optical fiber measured by the temperature measuring host will differ greatly from the temperature directly measured by the temperature measuring element (because the intensity of the pulsed laser emitted by the same laser source will double or cancel when interfering, resulting in serious distortion of the temperature measurement data). At this time, the temperature measuring host determines that the data is unreasonable and thus discards the set of temperature measurement data, and randomly adjusts the time interval for the next pulsed laser emission and measures again, so that the pulsed laser transmission times of the master and slave machines are staggered, until the measured data is within a reasonable range and the emission time is stopped (considering that the laser transmission time is extremely short, it is entirely possible that the laser transmission time is staggered and does not interfere with each other after multiple adjustments), thereby ensuring continuous high-reliability temperature measurement protection under fault conditions to the greatest extent.

[0026] The system can also realize mutual calibration of temperature measurement accuracy between the temperature measuring host A1 and the temperature measuring host B1′: since the actual temperature values ​​of the two reference optical fibers at the head and the tail of the temperature measuring optical fiber are respectively obtained through the temperature measuring elements in the temperature measuring host A1 and the temperature measuring host B1′, the signal processing unit can realize multi-point adjustment of the temperature calibration coefficients of the temperature measuring host A1 and the temperature measuring host B1′ by comparing the actual temperature values ​​at the two reference optical fibers with the temperature values ​​measured by the temperature measuring optical fiber. Compared with the prior art that can only adjust and calibrate at a single point (only one set of reference optical fibers and temperature measuring elements are set in a temperature measuring host chassis), the problem of low temperature measurement accuracy caused by serious signal attenuation at the tail end due to the long use distance of the temperature measuring optical fiber is greatly reduced, thereby improving the temperature measurement accuracy of the optical fiber temperature measurement system.

[0027] In the optical fiber temperature measurement system of the present embodiment, one of the reference optical fiber A 8 and the temperature measuring element A 9, and the reference optical fiber B 8 and the temperature measuring element B 9' can be eliminated, and the temperature measuring host A 1 and the temperature measuring host B 1' only use one of the groups to calibrate the temperature measurement accuracy; if the temperature measuring optical fiber is broken, the actual temperature value at the reference optical fiber of the temperature measuring host A1 or A2 is shared through the wireless communication path between the temperature measuring hosts A1 and A2 or the communication optical fiber path separately set up in parallel with the temperature measuring optical fiber. Embodiment 2

[0028] This embodiment is a further improvement on the high reliability and high precision optical fiber temperature measurement system provided in the first embodiment. The difference between this embodiment and the first embodiment is that: a temperature measurement host A'11 is respectively connected in series with a reference optical fiber A8, a temperature measurement optical fiber 2, and a reference optical fiber B8', wherein the temperature measurement host A'11 includes a signal processing unit A'14, a temperature measurement element A9, a wavelength division multiplexer A6 and its photoelectric detector A7, an optical switch 3 and its pulse laser source unit A5, a wavelength division multiplexer B6' and its photoelectric detector B7', and a temperature measurement element B9'; (that is, the two ends of the temperature measurement optical fiber 2 sequentially connect the reference optical fiber A8, the wavelength division multiplexer A6, the optical switch 3, the wavelength division multiplexer B6', and the reference optical fiber B8' in series to form a ring-shaped temperature measurement optical fiber loop, and the signal processing unit A'14 is respectively: electrically connected to the temperature measurement element A9 provided at the reference optical fiber A8, and sequentially connected to the photoelectric detector A9. 7 is electrically connected to the wavelength division multiplexer A 6 optical fiber, which is in turn electrically connected to the pulse laser source unit A 5 and the optical switch 3 optical fiber, and is electrically connected to the optical switch 3, which is in turn electrically connected to the photodetector B 7' and the wavelength division multiplexer B 6' optical fiber, and is electrically connected to the temperature measuring element B 9' located at the reference optical fiber B 8'); the rest of the structures are the same.

[0029] Here’s how it works: When the temperature measuring host A'11 is installed on site and the temperature measuring optical fiber 2 is laid, the system starts to run the self-test under normal conditions after power is turned on: Step 1, the signal processing unit A'14 controls the pulse laser source unit A5 to emit pulse laser for temperature measurement, and controls the optical switch 3 to make the pulse laser pass through the wavelength division multiplexer A6 and the reference optical fiber A8 and then enter the temperature measurement optical fiber 2, and then use the wavelength division multiplexer A6 and the photodetector A7 to detect and calculate the uncalibrated measured temperature value of each point of the entire annular temperature measurement optical fiber by the signal processing unit A'14 (the specific temperature measurement process is the fiber grating type or fully distributed optical fiber temperature measurement principle of the prior art, which is not repeated here), and at the same time, the temperature measuring element A9 measures the actual temperature information of the reference optical fiber A8 and calibrates the above-mentioned uncalibrated measured temperature value.

[0030] Step 2, following step 1, the signal processing unit A'14 controls the pulse laser source unit A5 to emit pulse laser for temperature measurement, and controls the optical switch 3 to allow the pulse laser to pass through the wavelength division multiplexer B6' and the reference optical fiber B8' and then enter the temperature measuring optical fiber 2, and then use the wavelength division multiplexer B6' and the photodetector B7' to detect and calculate the uncalibrated measured temperature value of each point of the entire annular temperature measuring optical fiber (the specific process is the same as the temperature measurement principle of the temperature measuring optical fiber in step 1, which will not be repeated here), and at the same time, the temperature measuring element B9' measures the actual temperature information at the reference optical fiber B8'.

[0031] When the temperature measurement in step 2 is completed, the signal processing unit A'14 is ready to start the next temperature measurement cycle from steps 1 and 2, and repeat the process over and over again.

[0032] In the case of abnormal optical fiber temperature measurement system, the processing method is as follows: 1) When any one of the wavelength division multiplexer A 6, the photoelectric detector A 7, the reference optical fiber A 8 and the temperature measuring element A 9, or the wavelength division multiplexer B 6', the photoelectric detector B 7', the reference optical fiber B 8 and the temperature measuring element B 9' fails, the signal processing unit A'14 immediately switches the other of the two into the temperature measuring state, and the mutual redundancy backup can greatly improve the reliability of the system; 2) When the temperature measuring optical fiber is broken, the optical fiber temperature measuring system can compare the calibrated temperature measuring optical fiber length after construction with the temperature measuring optical fiber length measured by the signal processing unit A'14 to confirm the temperature measuring optical fiber is broken and the position of the breakpoint. At this time, if the optical switch 3 is dual-channel, that is, it is turned on at the same time, the wavelength division multiplexer A6, the photoelectric detector A7, the reference optical fiber A8 and the temperature measuring element A9, and the wavelength division multiplexer B6', the photoelectric detector B7', the reference optical fiber B8 and the temperature measuring element B9' all start temperature measurement, and pulse laser temperature measurement is emitted from the left and right ends of the temperature measuring optical fiber 2 at the same time, so that the temperature measurement protection of the protected object can continue, avoiding the problem that after the temperature measuring optical fiber is broken, the temperature of the optical fiber in the area behind the breakpoint cannot be measured in the prior art. If the optical switch 3 is a single channel, the wavelength division multiplexer A 6, the photodetector A 7, the reference optical fiber A 8 and the temperature measuring element A 9, and the wavelength division multiplexer B 6', the photodetector B 7', the reference optical fiber B8 and the temperature measuring element B 9' perform temperature measurement alternately, and pulse laser temperature measurement is emitted alternately from the left and right ends of the temperature measuring optical fiber 2 at the same time, and the obtained data are spliced ​​into complete temperature measurement data.

[0033] In the optical fiber temperature measurement system of this embodiment, one of the reference optical fiber A 8 and the temperature measuring element A 9, and the reference optical fiber B 8 and the temperature measuring element B 9' can be eliminated; the temperature measurement host A'11 only uses one of the groups to calibrate the temperature measurement accuracy.

[0034] The above embodiments are examples of preferred implementation modes of the present invention, and are not limitations on the optical fiber temperature measurement system. Without affecting the essential conditions of the present invention, the components in the above embodiments can be changed, modified, replaced, combined, and simplified according to actual needs, and all of them should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An optical fiber temperature measurement system, characterized in that: The system comprises a temperature measuring host A, a temperature measuring host B, and a reference optical fiber A and a temperature measuring optical fiber which are sequentially connected in series between the temperature measuring host A and the temperature measuring host B; wherein the temperature measuring host A is mainly composed of a signal processing unit A, a pulse laser source unit A, a wavelength division multiplexer A, a photoelectric detector A and a temperature measuring element A; the signal processing unit A is respectively: electrically connected to the pulse laser source unit A, electrically connected to the photoelectric detector A in sequence, connected to the wavelength division multiplexer A optical fiber, and electrically connected to the temperature measuring element A; the reference optical fiber A is then sequentially connected to the wavelength division multiplexer A and the pulse laser source unit A optical fiber; the reference optical fiber A is coiled around the temperature measuring host A and the temperature measuring element A is arranged therein; the temperature measuring host B is mainly composed of a signal processing unit B, a pulse laser source unit B, a wavelength division multiplexer B and a photoelectric detector B; the signal processing unit B is respectively: electrically connected to the pulse laser source unit B, which is in turn electrically connected to the photoelectric detector B and optically connected to the wavelength division multiplexer B; the reference optical fiber B is then in turn connected to the wavelength division multiplexer B and the pulse laser source unit B; the temperature measuring host A and the temperature measuring host B are in a master-slave operation relationship with each other.

2. The optical fiber temperature measurement system according to claim 1, characterized in that: The temperature measuring optical fiber and the temperature measuring host B are also connected in series with a reference optical fiber B, and the temperature measuring host B also includes a temperature measuring element B; the signal processing unit B is electrically connected to the temperature measuring element B; the reference optical fiber B is coiled in the temperature measuring host B, and the temperature measuring element B is arranged thereon.

3. The optical fiber temperature measurement system according to claim 2, characterized in that: The temperature measuring host A and the temperature measuring host B exchange messages within a predetermined time through the temperature measuring optical fiber, and the messages at least include the communication heartbeat of the temperature measuring host A or B, whether the temperature measuring function of the temperature measuring host A or B is faulty, the temperature measurement start / stop signal of the temperature measuring host A or B, and the actual temperature at the reference optical fiber A or B measured by the temperature measuring element A or B in the temperature measuring host A or B.

4. The optical fiber temperature measurement system according to claim 3, characterized in that: The communication heartbeat of the temperature measuring host A or B is to send a message to the other party of the interconnection at a certain period of time as agreed in the communication protocol, and judge whether the communication link between the two parties of the interconnection has been disconnected according to the response of the other party.

5. The optical fiber temperature measurement system according to claim 2, 3 or 4, characterized in that: The temperature measuring element A or B is a platinum electrode or a thermocouple temperature measuring element.

6. An optical fiber temperature measurement system, characterized in that: The system includes a temperature measuring host A' which is respectively connected in series with a reference optical fiber A and a temperature measuring optical fiber, wherein the temperature measuring host A' includes a signal processing unit A', a temperature measuring element A, a wavelength division multiplexer A and a photoelectric detector A thereof, an optical switch and a pulse laser source unit A thereof, and a wavelength division multiplexer B and a photoelectric detector B thereof; the signal processing unit A' is respectively: electrically connected to the temperature measuring element A arranged at the reference optical fiber A, electrically connected to the photoelectric detector A and the optical fiber of the wavelength division multiplexer A in turn, electrically connected to the pulse laser source unit A and the optical fiber of the optical switch in turn, electrically connected to the optical switch, and electrically connected to the photoelectric detector B and the optical fiber of the wavelength division multiplexer B in turn.

7. The optical fiber temperature measurement system according to claim 6, characterized in that: The two ends of the temperature measurement optical fiber sequentially connect the reference optical fiber A, the wavelength division multiplexer A, the optical switch, and the wavelength division multiplexer B optical fiber in series to form a ring-shaped temperature measurement optical fiber loop.

8. The optical fiber temperature measurement system according to claim 7, characterized in that: The annular temperature measurement optical fiber loop is also connected in series with a reference optical fiber B, and the temperature measurement host A' further includes a temperature measurement element B arranged at the reference optical fiber B and electrically connected to the signal processing unit A'.

9. The optical fiber temperature measurement system according to claim 8, characterized in that: The temperature measuring element A or B is a platinum electrode or a thermocouple temperature measuring element.

10. The optical fiber temperature measurement system according to claim 6, 7, 8 or 9, characterized in that: The optical switch is a single-channel or dual-channel optical switch.

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