CN106644276A - Monitoring system for detecting tank leakage by utilizing distributed optical fiber - Google Patents
Monitoring system for detecting tank leakage by utilizing distributed optical fiber Download PDFInfo
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- CN106644276A CN106644276A CN201710018076.0A CN201710018076A CN106644276A CN 106644276 A CN106644276 A CN 106644276A CN 201710018076 A CN201710018076 A CN 201710018076A CN 106644276 A CN106644276 A CN 106644276A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/002—Investigating fluid-tightness of structures by using thermal means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
- G01K11/324—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres using Raman scattering
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/38—Investigating fluid-tightness of structures by using light
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- General Physics & Mathematics (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
The invention provides a monitoring system for detecting tank leakage by utilizing a distributed optical fiber. The monitoring system comprises a laser device, a wavelength division multiplexer, a sensing optical fiber wound on the exterior of a tank, a photovoltaic conversion module, a signal processing module and an alarming module, wherein the laser device is connected with a first de-multiplexing port of the wavelength division multiplexer; the sensing optical fiber is connected with a multiplexing port of the wavelength division multiplexer; the photovoltaic conversion module is connected with a second de-multiplexing port and a third de-multiplexing port of the wavelength division multiplexer; the photovoltaic conversion module is connected with the signal processing module; the alarming module is connected with the signal processing module; the photovoltaic conversion module is connected with the signal processing module; the alarming module is connected with the signal processing module; and the Stokes light and anti-Stokes light reflected by the sensing optical fiber are utilized to calculate a temperature value and the position information of a leakage point. The monitoring system provided by the invention utilizes an optical time domain reflecting technique to quickly position the leakage point of tank gas, so that major accidents can be prevented from happening.
Description
Technical field
The present invention relates to tank body leakage detection field, and in particular to a kind of utilization distribution type fiber-optic detects the prison of tank body leakage
Examining system.
Background technology
Large-scale LNG (liquefied natural gas) easily causes fire once tank body, crude oil tank body tank body occur destruction or leak
Calamity, blast and intoxication accident, cause the heavy losses of people's life and national wealth.Therefore, to large-scale LNG, (liquefaction is natural
Gas) tank body, crude oil tank body carries out daily monitoring and early warning is very important.
Because the environment residing for LNG (liquefied natural gas) tank body, crude oil tank body is inflammable and explosive, electrical sensor is easy to because of it
Producing electric spark can introduce new unsafe factor, be not suitable for using.Most widely used at present is acoustic emission testing technology, it
Signal is gathered using Acoustic radiating instrument, so as to understand the crackle and defect of liquefied gas storage, it is clear that this method is difficult to reach people
Large-scale liquefied gas storage is revealed over a long time, the requirement of real time on-line monitoring and early warning.Still an alternative is that, using optical fiber
Grating temperature sensing probe carries out leak detection, but due to the huge surface area of tank body, and impaired loci and leak point is not true
Qualitative, to reach effectively monitoring needs substantial amounts of sensing probe.
At present, 6mm apertures tank body leakage is world-famous puzzle, it is clear that acoustic emission testing technology and fiber grating temperature sensor
Technology cannot all meet such high-precision detection and localization, and the leakage for how detecting such micro-aperture is that Oil ＆ Gas Storage is badly in need of solution
Certainly problem.
The content of the invention
For defect of the prior art, the utilization distribution type fiber-optic that the present invention is provided detects the monitoring system of tank body leakage
System, using Optical time domain reflectance, can quickly be positioned to the leakage point of tank body gas, it is to avoid major accident occurs.
A kind of utilization distribution type fiber-optic that the present invention is provided detects the monitoring system of tank body leakage, including：Laser instrument, wavelength-division
Multiplexer, sensing optical fiber, photoelectric conversion module, signal processing module and the alarm module being wrapped in outside tank body；The laser instrument
It is connected with the first demultiplexing port of the wavelength division multiplexer, the sensing optical fiber connects with the multiplexing port of the wavelength division multiplexer
Connect, the photoelectric conversion module is connected with the second demultiplexing port and the 3rd demultiplexing port of the wavelength division multiplexer, described
Photoelectric conversion module is connected with the signal processing module, and the alarm module is connected with the signal processing module；It is described to swash
Light device is used to produce pulse laser；The wavelength division multiplexer is used to isolate stoke in the light returned from the sensing fiber reflection
This light and anti-Stokes light；The photoelectric conversion module is used for the stokes light of isolating the wavelength division multiplexer and anti-
Stokes light is converted to the first electric signal and the second electric signal；The signal processing module is used for according to first electric signal
With second electric signal, the positional information of temperature value and leakage point is calculated；If the alarm module is used for signal transacting
Module detects leakage, then reported to the police.
Preferably, the signal processing module specifically for：First electric signal and the second electric signal are carried out into modulus
It is converted to the first data and the second data, the intensity of the first data correspondence stokes light, the second data correspondence
The intensity of anti-Stokes light；According to first data and the ratio of second data, temperature detection value is obtained；Will be described
Temperature detection value is compared with standard temperature, if temperature detection value is more than temperature error threshold with the difference of standard temperature
Value, then according to temporal information, obtain the positional information of leakage point.
Preferably, it is described according to first data and the ratio of second data, temperature detection value is obtained, including：
The corresponding first position information of first data is calculated according to temporal information, in being stored in first position sequence；According to temporal information
Calculate the corresponding second place information of the second data；Search in the first position sequence and most connect with the second place information
Near first position information；According to the first position information for finding and the ratio of the second place information, temperature inspection is obtained
Measured value.
Preferably, it is described that the positional information of leakage point is obtained according to temporal information, including：According to temporal information from coordinate
The positional information of leakage point is obtained in database, the pass of temporal information and positional information is previously stored with the coordinate database
System's correspondence table.
Preferably, also including threedimensional model matching module, the threedimensional model matching module and the signal processing module
Connection, the threedimensional model matching module is used to find the point matched with the positional information in the three-dimensional model, mark matching
The point for arriving, by display the threedimensional model is shown, wherein, the threedimensional model builds in advance according to detection zone.
Preferably, the signal processing module specifically for：If first electric signal and the second electric signal carry out modulus
It is converted to the first data and the second data, the intensity of the first data correspondence stokes light, the second data correspondence
The intensity of anti-Stokes light；First data are deviateed into the first standard value, and second number deviates the second standard value, then
According to temporal information, the positional information of leakage point is obtained.
Preferably, the laser instrument adopts optical fiber laser.
Preferably, the laser instrument adopts 1550 nano lasers.
Preferably, the internal layer coating of the sensing optical fiber is nickel coating, and outer coating is SiO2/ EA/PUA hybrid materials.
Preferably, the photoelectric conversion module includes two APD avalanche photodides and two-way amplifying circuit.
Description of the drawings
Fig. 1 is the structural frames of the monitoring system of utilization distribution type fiber-optic detection tank body leakage provided in an embodiment of the present invention
Figure；
Fig. 2 is Raman scattering principle figures；
Fig. 3 is the frequency relation figure in Raman scatterings between incident light, anti-Stokes light and stokes light；
Fig. 4 is a kind of schematic flow sheet of signal processing method in signal processing module provided in an embodiment of the present invention；
Fig. 5 is the schematic flow sheet of another kind of signal processing method in signal processing module provided in an embodiment of the present invention.
Specific embodiment
The embodiment of technical solution of the present invention is described in detail below in conjunction with accompanying drawing.Following examples are only used for
Technical scheme is clearly illustrated, therefore is intended only as example, and the protection of the present invention can not be limited with this
Scope.
It should be noted that unless otherwise stated, technical term used in this application or scientific terminology should be this
The ordinary meaning that bright one of ordinary skill in the art are understood.
As shown in figure 1, utilization distribution type fiber-optic provided in an embodiment of the present invention detects the monitoring system of tank body leakage, bag
Include：Laser instrument, wavelength division multiplexer, the sensing optical fiber being wrapped in outside tank body, photoelectric conversion module, signal processing module and warning mould
Block.Laser instrument is connected with the first demultiplexing port of wavelength division multiplexer, and sensing optical fiber is connected with the multiplexing port of wavelength division multiplexer,
Second demultiplexing port of photoelectric conversion module and wavelength division multiplexer and the 3rd demultiplexing port be connecteds, it is ensured that stokes light and
Anti-Stokes light can be exported respectively from the second demultiplexing port and the 3rd demultiplexing port, wherein, the first demultiplexing port
The operation wavelength of corresponding pulse laser is located at the centre of stokes light and anti-Stokes optical wavelength.Photoelectric conversion module with
Signal processing module connects, and alarm module is connected with signal processing module.Laser instrument is used to produce pulse laser；Wavelength division multiplexer
For isolating stokes light and anti-Stokes light from the light of sensing fiber reflection time；Photoelectric conversion module is used for ripple
The stokes light and anti-Stokes light that division multiplexer is isolated is converted to the first electric signal and the second electric signal；Signal transacting
Module is used for according to the first electric signal and the second electric signal, is calculated the positional information of temperature value and leakage point；Alarm module
If detecting leakage for signal processing module, reported to the police.
Wherein, depending on sensing precision of the density of Optical Fiber Winding according to detection, winding density is bigger, and accuracy of detection is higher.
Optical time domain reflectance (OTDR) is used primarily for evaluating the performance of telecommunication optical fiber, optical cable and coupler, is inspection
Fibre loss, the means of fiber failure, its working mechanism is to launch light pulse to tested optical fiber, and Raman scattering phenomenon occurs,
Back-scattering light and forward scattering light are formed in optical fiber, as shown in Figure 2.Wherein, back-scattering light back-propagation rising to optical fiber
Top (the namely injection end of laser pulse), due to a scattering on the corresponding optical fiber of scattered light that each is dorsad propagated
Point, therefore, the position that scattering point occurs on optical fiber is just can determine whether out according to the traveling time of back-scattering light,
Wherein, c is speed of the light in sensing optical fiber, and t is to the total time for receiving signal, IOR after signal transmitting
It is optical fibre refractivity.
The present embodiment mainly utilizes light Raman (Raman) scattered signal in a fiber, enters the measurement of trip temperature and position.
The change of Raman scattered signals is relevant with temperature, and Raman scattered signals are relatively easily obtained and analyzed, as shown in figure 3,
Raman scatterings can produce the signal of two different frequencies：Stokes light (Stokes) and anti-Stokes light (Anti-
Stokes), the wavelength ratio optical source wavelength of stokes light is long, the wavelength of anti-Stokes light be it is shorter than optical source wavelength, for example, such as
Fruit is 1550nm as the light that sends of laser instrument of light source, then the wavelength of stokes light is 1663nm, anti-Stokes light
Wavelength be 1450nm.Sensing optical fiber is modulated by external temperature makes the anti-Stokes light intensity in optical fiber change, and this
Lentor light be influenced by temperature it is less, so the ratio of anti-Stokes light and stokes light provides the absolute finger of temperature
Show, can be realized to the distributed measurement along fiber optic temperature field using this principle.By gather and analyze incident light pulse from
The time and intensity information of the Raman back-reflection light produced when propagating in optical fiber after one end (injection end) injection of optical fiber is obtained
To corresponding position and temperature information, after the temperature and positional information of every bit is learnt, it is possible to obtain one with regard to whole
The temperature curve of the diverse location of optical fiber.
Operation principle is as follows：Monitoring system is started working with a synchronizing signal as starting point, and laser instrument receives synchronization
Launch a pulse laser after signal, meanwhile, signal processing module is received and start after synchronizing signal timing；Pulse laser Jing ripples
Division multiplexer is entered after sensing optical fiber, produces stokes light and anti-Stokes light, stokes light and anti-Stokes light
Reflect in communication process, the stokes light and anti-Stokes light being reflected back enters from the multiplexing port of wavelength division multiplexer
Separated after entering, respectively from the second demultiplexing port of wavelength division multiplexer and the 3rd demultiplexing port output, Jing opto-electronic conversion moulds
Block is converted to input signal processing module after electric signal, after carrying out analog-to-digital conversion, according to Optical time domain reflectance, obtains light anti-
The temperature value and positional information of exit point；When the detection for receiving next synchronizing signal and starting next round.Once in tank body
Gas is leaked, and can at once cause the change of leakage point temperature, causes the change of the anti-Stokes light in optical fiber, is reflected by light
The change of the temperature value of point can be determined whether to leak, further according to the time (with synchronizing signal as initial time) of collection light
With the positional information that light speed in a fiber is obtained leakage point.
The monitoring system of the present embodiment, is positioned using Optical time domain reflectance to leakage point so that staff
Leakage point can be quickly found to be keeped in repair, it is to avoid major accident occurs, effective protection people life property safety；Transmitting is once
Pulse laser, can simultaneously monitor the monitoring point that tens kilometers of optical fiber are covered, and monitoring area is wide；Due to being detected using light, no
Safer comprising any electrical equipment, reliability is higher, it is adaptable to detect LNG (liquefied natural gas) tank body, crude oil tank body etc.
The leakage of dangerous material.Surveillance center is connected by network with multiple stage monitoring system, by the data summarization of multiple stage monitoring system to prison
The multiple regions of remote monitoring by control center, Surveillance center, save the input of personnel.
Wherein, as shown in figure 4, specifically including the step of process signal in signal processing module：
Step S1, carries out the first electric signal and the second electric signal analog-to-digital conversion and obtains the first data and the second data, the
The intensity of one data correspondence stokes light, the intensity of the second data correspondence anti-Stokes light.
Step S2, according to the first data and the ratio of the second data, obtains temperature detection value.
Wherein, the formula of calculating temperature is：
Wherein, k is Boltzmann constant, and h is Planck's constant；C is the light velocity in vacuum；ν is incident optical frequency；T is prison
Measuring point temperature；T0For reference temperature；Pas(T)/Ps(T) it is the ratio of the two paths of signals intensity at temperature T；Pas(T0)/Ps(T0) be
Temperature T0Under two paths of signals intensity ratio.
Step S3, temperature detection value is compared with standard temperature, if the difference of temperature detection value and standard temperature
Value is more than temperature error threshold value, then according to temporal information, obtain the positional information of leakage point.
Wherein, temporal information is, with synchronizing signal as initial time, to receive the stokes light and anti-this support being reflected back
The time of Ke Si light.
Wherein, standard temperature is the temperature of optical fiber under normal condition, and standard temperature can be by before detecting
Temperature value carries out statistical computation and obtains.
The change of temperature is judged using threshold value, is easily disturbed by ambient temperature, in order to reduce external environment pair
The impact of monitoring result, improves accuracy of detection, and the preferred embodiment mode of step S3 is：Temperature detection in record a period of time
Value, if temperature detection value is undergone mutation in the unit interval, regards as leaking, and according to temporal information, obtains leakage point
Positional information.The temperature that the external world causes is than shallower, and it is more violent to leak the temperature change for causing, therefore, it is prominent according to temperature
Become to judge the method strong antijamming capability of leakage accident, contribute to reducing false alarm rate.
In the monitoring system that tank body leakage is detected using distribution type fiber-optic, spatial resolution is of crucial importance, and it reflects
The mikey that system minimum can be differentiated, directly decides the sterically defined degree of accuracy of system.Spatial resolution is higher, space
Positioning precision is higher.This index has in actual applications important meaning, such as, in petroleum pipeline leakage monitoring, such as
Fruit leakage region is smaller, and the sensing optical fiber of only small range can be sensed, if System spatial resolution is than relatively low, just not
Leakage can be in time found, even if finding also determine one than larger scope, the difficulty of maintenance is increased.Equally, exist
It is also thus, accurately positioning and accurate early warning can not be made to the event location that humidity changes in colliery.Therefore, improve
System spatial resolution is particularly important.
Because anti-Stokes light is different with the wavelength of stokes light, this can cause the propagation speed of two-beam in a fiber
Degree is different.Because the sample rate of two-way light during analog-to-digital conversion is identical, the spread speed of anti-Stokes light and stokes light is not
Together, then the data for mutually gathering in the same time will correspond to different fiber positions, this reduces the spatial resolution of system, subtract
Little positioning precision.As the fiber position difference of the increase of fiber lengths, anti-Stokes light and stokes light also gradually increases
Greatly, when fiber lengths are 10km, the fiber position difference of anti-Stokes light and stokes light can reach 10-20m.In order to and
Solve the above problems, improve positioning precision, step S2 in signal processing module is optimized, as shown in figure 5, implementing
Mode is to include：
Step S21, according to temporal information the corresponding first position information of the first data is calculated, and is stored in first position sequence
In.
Wherein, the position of the stokes light that first position information was collected for current time pip in a fiber,
First position sequence stores the corresponding first position information of all stokes lights for collecting.
Step S22, according to temporal information the corresponding second place information of the second data is calculated.
Wherein, the position of the anti-Stokes light that second place information was collected for current time pip in a fiber
Put.
Step S23, searches and the immediate first position information of second place information in the sequence of first position.
Wherein, because stokes light spread speed is fast, the fiber position of the stokes light that synchronization is collected will
More remote than the fiber position of anti-Stokes light, such as the fiber position of a certain anti-Stokes light at the moment, collecting is
9.98km, then the fiber position of the stokes light for now collecting may be 10km, therefore, select storage Stokes
The corresponding first position information of light, can match in real time immediate with second place information in the sequence of first position
One positional information.
Step S24, according to the ratio of the first position information and second place information for finding, obtains temperature detection value.
Then, temperature detection value is compared with standard temperature, if the difference of temperature detection value and standard temperature
More than temperature error threshold value, then the corresponding point of second place information is leakage point.
The detecting system that the present embodiment is provided can detect 0.5 DEG C of temperature change, and space minimum resolution is 0.25 meter,
Really realize distributed monitoring.
In order to be quickly obtained the particular location of leakage point, temporal information and actual physics position in time shaft are built in advance
Corresponding relation between putting is stored in coordinate database, and the positional information of actual physical location includes the area residing for monitoring point
Which position in domain, which tank body and tank body, facilitates monitoring personnel to position, therefore, step S3 is specifically included：Believed according to the time
Breath obtains the positional information of leakage point from coordinate database.
Because the scope for sensing fiber distribution is wider, for the particular location for more intuitively obtaining leak point, pacifying
When filling whole monitoring device, threedimensional model can in advance be built according to the region of actual monitoring, and according to the distribution situation of optical fiber,
Mark out in threedimensional model and.Therefore, the monitoring system of the present embodiment also includes threedimensional model matching module, threedimensional model matching
Module is connected with signal processing module, and threedimensional model matching module is used to find in the three-dimensional model and signal processing module resolving
The point of the positional information matching for going out, and the point that mark is matched, threedimensional model is shown by display.Alarm module sends alarm
Afterwards, the threedimensional model in display can be highlighted the leakage point for detecting, and monitoring personnel can rapidly be obtained by display
The region residing for leakage point is taken, in concrete which position of which tank body.
Due to pressure reduction larger inside and outside tank body, disturbance is caused to sensing optical fiber from the gas of tank body internal leakage, therefore, may be used also
So that by detecting leakage point with the presence or absence of the larger disturbing signal of amplitude in detection reflected light, its concrete detection method includes：
Step S10, carries out the first electric signal and the second electric signal analog-to-digital conversion and obtains the first data and the second data, the
The intensity of one data correspondence stokes light, the intensity of the second data correspondence anti-Stokes light.
First data are deviateed the first standard value by step S20, and the second data deviate the second standard value, then according to the time
Information, obtains the positional information of leakage point.
Wherein, the first standard value is the intensity of stokes light under normal circumstances, and the second standard value is anti-under normal circumstances
The intensity of stokes light.
It is, of course, also possible to disturbing signal detecting and temperature detection are combined, to improve the accuracy rate of detection.
In addition, in order to improve optical fiber sensing capability, sensing coating of the optical fiber using specially treated.Sensing optical fiber is using double-deck
Coating process, preferably internal layer coating be nickel coating, outer coating be SiO2/EA/PUA (silica/epoxy propylene acid esters/
Urethane acrylate) hybrid material.This pair of coating so that sensing fiber optic temperature sensitivity coefficient is high, temperature is had compared with
Good stability, stress sensitivity coefficient is high, improves certainty of measurement and the degree of accuracy of temperature.
Laser instrument is easily warm by work and operating current is affected, and causes power and the wavelength of output to change.When
When the centre wavelength of laser instrument changes, the decay in spread fiber also can change, and in a fiber spontaneous Raman dissipates
Penetrating the wavelength of the two-way scattered light of generation also can change, and also resulting in the loss factor in optical fiber can change, due to
The impact of the bandwidth of wavelength division multiplexer median filter, can make two-way light also can change in the loss of wavelength division multiplexer, these
Factor can all make the temperature of final demodulation produce error.Therefore, the stability of the output light of laser instrument must be high.This enforcement
Laser instrument in example adopts optical fiber laser.Good beam quality, good stability, simple structure, the volume of optical fiber laser output
Little, low cost, directly by optical fiber output pulse laser, reduces the loss of the light energy in output procedure.
The wavelength of laser instrument has certain relation with the intensity of Raman scatterings, and theory shows：The wavelength of laser instrument and spontaneous drawing
Graceful scattered light intensity is inversely proportional to, if the intensity that obtain strong spontaneous Raman scattering light can reduce the wavelength of laser instrument, but
Wavelength is not more low better, and in a fiber loss is larger for the relatively low light of wavelength, and propagation distance is not far, the noise of system
Than cannot be guaranteed.Laser wavelength is typically chosen 980nm, 1310nm or 1550nm, wherein, the laser of 1550nm is in optical fiber
Than larger, loss is smaller, and the wavelength of laser instrument is preferably 1550nm in the monitoring system of the present embodiment for transmission range.
Photodetector is mainly responsible for the conversion of photosignal in system, the quality of its performance directly with the letter of system signal
Make an uproar and compare, stability is relevant.The stokes light and anti-Stokes light of the needs detection in distributed fiber Raman sensor-based system
Comparison is faint, it is therefore desirable to big from responsiveness, the big photodetector of gain.Conventional photodetector is mainly PIN light
Electric diode and APD avalanche photodides.Wherein, APD avalanche photodides have high sensitivity, noise equivalent power low
The characteristics of, it is adapted to the detection of small-signal.Because stokes light and anti-Stokes light are after photoelectric conversion, electric signal is also
It is smaller, in addition it is also necessary to add amplifying circuit, amplifier will also meet low noise, high-gain, high bandwidth and high conversion rate
Feature.In order to improve sensitivity and the monitoring distance of monitoring system, the photoelectric conversion module in the present embodiment is using two responses
Spend the APD avalanche photodides of big high-gain to detect stokes light and anti-Stokes light respectively, and to be furnished with two-way
Amplifying circuit, for amplifying the signal that APD avalanche photodides are collected, the amplifier in amplifying circuit is preferably provided with low noise
The amplifier of sound, high-gain, high bandwidth and high conversion rate.
Finally it should be noted that：Various embodiments above only to illustrate technical scheme, rather than a limitation；To the greatest extent
Pipe has been described in detail with reference to foregoing embodiments to the present invention, it will be understood by those within the art that：Its according to
So the technical scheme described in foregoing embodiments can be modified, either which part or all technical characteristic are entered
Row equivalent；And these modifications or replacement, do not make the essence disengaging various embodiments of the present invention technology of appropriate technical solution
The scope of scheme, it all should cover in the middle of the claim of the present invention and the scope of specification.
Claims (10)
1. a kind of utilization distribution type fiber-optic detects the monitoring system of tank body leakage, it is characterised in that include：Laser instrument, wavelength-division are multiple
With device, the sensing optical fiber, photoelectric conversion module, signal processing module and the alarm module that are wrapped in outside tank body；
The laser instrument is connected with the first demultiplexing port of the wavelength division multiplexer, described to sense optical fiber and the wavelength-division multiplex
The multiplexing port connection of device, second demultiplexing port and threeth demultiplexing of the photoelectric conversion module with the wavelength division multiplexer
Port connects, and the photoelectric conversion module is connected with the signal processing module, the alarm module and the signal transacting mould
Block connects；
The laser instrument is used to produce pulse laser；
The wavelength division multiplexer is used to isolate stokes light and anti-Stokes in the light returned from the sensing fiber reflection
Light；
The photoelectric conversion module is used for the stokes light for isolating the wavelength division multiplexer and anti-Stokes light conversion
For the first electric signal and the second electric signal；
The signal processing module is used for according to first electric signal and second electric signal, is calculated temperature value and lets out
The positional information of leak source；
If the alarm module detects leakage for signal processing module, reported to the police.
2. system according to claim 1, it is characterised in that the signal processing module specifically for：
First electric signal and the second electric signal are carried out into analog-to-digital conversion and obtains the first data and the second data, first number
According to the intensity of correspondence stokes light, the intensity of the second data correspondence anti-Stokes light；
According to first data and the ratio of second data, temperature detection value is obtained；
The temperature detection value and standard temperature are compared, if temperature detection value is more than temperature with the difference of standard temperature
Degree error threshold, then according to temporal information, obtain the positional information of leakage point.
3. system according to claim 2, it is characterised in that described according to first data and second data
Ratio, obtains temperature detection value, including：
The corresponding first position information of first data is calculated according to temporal information, in being stored in first position sequence；
The corresponding second place information of second data is calculated according to temporal information；
Search in the first position sequence and the immediate first position information of the second place information；
According to the first position information for finding and the ratio of the second place information, temperature detection value is obtained.
4. system according to claim 2, it is characterised in that described according to temporal information, obtains the position letter of leakage point
Breath, including：The positional information of leakage point is obtained from coordinate database according to temporal information, is deposited in advance in the coordinate database
Contain temporal information and answer table with the relation pair of positional information.
5. system according to claim 2, it is characterised in that also including threedimensional model matching module, the threedimensional model
Matching module is connected with the signal processing module, the threedimensional model matching module be used for find in the three-dimensional model with it is described
The point of positional information matching, marks the point for matching, and by display the threedimensional model is shown, wherein, the threedimensional model
Built in advance according to detection zone.
6. system according to claim 1, it is characterised in that the signal processing module specifically for：
First electric signal and the second electric signal are carried out into analog-to-digital conversion and obtains the first data and the second data, first number
According to the intensity of correspondence stokes light, the intensity of the second data correspondence anti-Stokes light；
If first data deviate the first standard value, and second number deviates the second standard value, then according to temporal information, obtain
To the positional information of leakage point.
7. system according to claim 1, it is characterised in that the laser instrument adopts optical fiber laser.
8. system according to claim 1, it is characterised in that the laser instrument adopts 1550 nano lasers.
9. system according to claim 1, it is characterised in that the internal layer coating of the sensing optical fiber is nickel coating, outer layer
Coating is SiO2/ EA/PUA hybrid materials.
10. system according to claim 1, it is characterised in that the photoelectric conversion module includes two APD avalanche optoelectronics
Diode and two-way amplifying circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710018076.0A CN106644276A (en) | 2017-01-11 | 2017-01-11 | Monitoring system for detecting tank leakage by utilizing distributed optical fiber |
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| CN108760162A (en) * | 2018-05-23 | 2018-11-06 | 北京目黑科技有限公司 | leakage detection device and method |
| CN108982516A (en) * | 2018-07-16 | 2018-12-11 | 中国科学院合肥物质科学研究院 | A kind of distribution type fiber-optic sack cleaner leak-off pocket locating and detecting device and its method |
| CN109798448A (en) * | 2019-03-06 | 2019-05-24 | 中国计量大学 | Concrete duct leakage experiment device and method based on anti-Stokes light filtering |
| CN113447159A (en) * | 2021-08-30 | 2021-09-28 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factor |
| CN113532303A (en) * | 2021-07-05 | 2021-10-22 | 浙江大学 | Device and method for testing strain position of object by using external strain |
| US11494888B2 (en) * | 2018-01-18 | 2022-11-08 | Hitachi, Ltd. | Work terminal, oil leakage detection apparatus, and oil leakage detection method |
| CN116817175A (en) * | 2023-08-31 | 2023-09-29 | 四川雅韵能源开发有限责任公司 | Liquefied natural gas storage tank monitoring and early warning method based on optical fiber sensing |
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| CN108426767A (en) * | 2018-03-09 | 2018-08-21 | 大连理工大学 | A kind of pressure piping method for crack based on Distributed Optical Fiber Sensing Techniques |
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| CN113447159A (en) * | 2021-08-30 | 2021-09-28 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factor |
| CN113447159B (en) * | 2021-08-30 | 2021-11-09 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Wind tunnel cold leakage monitoring method based on global normal distribution and local outlier factor |
| CN116817175A (en) * | 2023-08-31 | 2023-09-29 | 四川雅韵能源开发有限责任公司 | Liquefied natural gas storage tank monitoring and early warning method based on optical fiber sensing |
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