CN210567567U

CN210567567U - Gas leakage detection device based on DAS system

Info

Publication number: CN210567567U
Application number: CN201920817310.0U
Authority: CN
Inventors: 谢丰权; 张洋; 杜新民; 张坦
Original assignee: PINGHU BOHUI COMMUNICATION TECHNOLOGY CO LTD; Shanghai Bohui Technology Co ltd
Current assignee: PINGHU BOHUI COMMUNICATION TECHNOLOGY CO LTD; Shanghai Bohui Technology Co ltd
Priority date: 2019-05-31
Filing date: 2019-05-31
Publication date: 2020-05-19
Anticipated expiration: 2029-05-31

Abstract

The utility model discloses a gas leakage detection device based on DAS system, including test tube way, pipeline bracket, outside detection optic fibre, inside detection optic fibre, optical fiber protection tube, fiber support, loading system and pressure measurement mechanism, the test tube install in on the pipeline bracket, be equipped with the leak hole on the test tube way, fiber support follows the setting along the line of test tube way, outside detection optic fibre place in on the fiber support, DAS host computer is connected to its one end, and the other end is connected inside detection optic fibre, the test tube internal fixation has the optical fiber protection tube, optical fiber protection tube and outside intercommunication, inside detection optic fibre is arranged in the optical fiber protection tube, loading system reaches is connected to the one end of test tube way pressure measurement mechanism. The utility model discloses a gas leakage detection device can accurately detect whether take place gas leakage and location and reveal the position, has the advantage that the monitoring accuracy is high, response speed is fast.

Description

Gas leakage detection device based on DAS system

Technical Field

The utility model belongs to the technical field of optical fiber communication sensing gas leakage detection, concretely relates to gas leakage detection device based on DAS system.

Background

At the present stage, a stress wave detection method and a negative pressure wave detection method are mainly used for monitoring the leakage of the gas pipeline. The principle of the stress wave detection method is that the power spectrum of the stress wave signal of the actually measured pipeline is changed when gas in the pipeline leaks, the leakage can be detected by analyzing the change, and the pipeline vibration is difficult to describe by an analytic method due to a plurality of factors influencing the propagation of the stress wave of the pipeline. The principle of the negative pressure wave detection method is that when gas leakage occurs in a pipeline, the local gas is reduced due to gas loss in the pipeline, so that instantaneous pressure reduction and speed difference occur. This instantaneous pressure drop acts on the medium and propagates through the pipeline and the medium as a source of pressure reducing waves upstream and downstream of the leak. When the pressure before the leak is used as a reference standard, the pressure reduction wave generated at the time of the leak is called a negative pressure wave, and this method is called a negative pressure wave detection method. And the head end and the tail end of the pipeline are respectively provided with a pressure transmitter, and the position of a leakage point can be calculated according to the time difference of the negative pressure wave generated by leakage to the upstream and downstream and the propagation speed of the pressure wave in the pipeline. The negative pressure wave method has higher response speed and positioning accuracy, but is greatly influenced by the operating condition of the pipeline, and the false alarm rate is high. Therefore, a monitoring method with high monitoring precision and accurate positioning is urgently needed for the pipe network.

SUMMERY OF THE UTILITY MODEL

To the problem that exists among the prior art, the utility model provides a gas leakage detection device based on DAS system, the utility model discloses can detect whether the gas pipeline takes place to leak and the position of leakage point, can detect the accuracy of test result simultaneously, provide technical support for the development of gas leakage detection technique.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides a gas leakage detection device based on DAS system, including test tube, pipeline bracket, outside detection optic fibre, inside detection optic fibre, fiber protection pipe, fiber support, loading system and pressure measurement mechanism, the test tube install in on the pipeline bracket, be equipped with the leak hole on the test tube, fiber support follows the setting along the line of test tube, outside detection optic fibre place in on the fiber support, DAS host computer is connected to its one end, and the other end is connected inside detection optic fibre, the test tube internal fixation has fiber protection pipe, fiber protection pipe and outside intercommunication, inside detection optic fibre arranges in the fiber protection pipe, loading system reaches pressure measurement mechanism is connected to the one end of test tube.

Preferably, the optical fiber protection tube is a PE tube.

As the preferred technical scheme, the pressurizing mechanism comprises an air compressor, a connecting hose and a switch valve, the air compressor is connected with one end of the test pipeline through the connecting hose, and the switch valve is installed on the connecting hose.

Preferably, the pressure detection mechanism is a pressure gauge, and the pressure gauge is attached to the connection hose.

Preferably, the set height of the external detection optical fiber is the same as the axial height of the test pipeline.

As a preferred technical scheme, the optical fiber support comprises a base, a connecting rod and a parallel rod, wherein the parallel rod is connected with the base through the connecting rod.

As a preferred technical scheme, the number of the leakage holes is 3, and the hole diameters of the 3 leakage holes are different.

DAS (Direct-Attached Storage), i.e., Direct-Attached Storage of open systems. The variation of the intensity and the phase of the backward Rayleigh scattered light in the detection optical fiber can be caused when the gas leaks, the sensing signal is collected by a data acquisition module and is transmitted to a computer for processing, a direct current signal is removed, a window function is added and FFT (Fast Fourier transform is a Fast algorithm of discrete Fourier transform) is carried out, a time domain signal and a frequency domain signal are obtained, and whether the gas leaks or not is judged according to the amplitude of the time domain signal before and after the gas leaks and the frequency variation leakage characteristic. Meanwhile, the position of the leakage is determined by adopting an OTDR (Optical Time Domain Reflectometer) technology, and the distance, namely the position of the gas leakage can be calculated according to the Time from the emission signal to the return signal and the speed of the light in the glass substance.

The leakage monitoring by using the distributed optical fiber sensing technology has multiple advantages, namely, the sensor is a common optical fiber, and has low cost, no radiation and strong anti-electromagnetic interference capability; no matter a gas pipe, a rare gas pipe and the like, when leakage occurs, sound fields inside and around the pipeline can change regularly, and the gas leakage condition can be judged by monitoring the changes; the monitoring system has long monitoring distance and no blind area, and accords with the characteristics of the pipeline.

Compared with the prior art, the beneficial effects of the utility model are that:

(1) the utility model discloses a gas leakage detection device can accurately detect whether take place gas leakage and location and reveal the position, has the advantage that the monitoring accuracy is high, response speed is fast.

(2) The utility model discloses a gas leakage detection device can calculate the leakage rate or the size of revealing the bore in the pipeline through the further analysis of data to gathering to the maintenance to the pipeline provides the reference.

(3) The utility model discloses a gas leakage detection device can verify the accuracy of test result, obtains the test structure under the different pipeline pressure, verifies the feasibility of the device on revealing the detection and using.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is the utility model discloses a gas leakage detection device's overall structure schematic diagram based on DAS system.

3 fig. 3 2 3 is 3 a 3 sectional 3 view 3 taken 3 along 3 a 3- 3 a 3 of 3 fig. 3 1 3. 3

FIG. 3 is a schematic structural view of a fiber optic shelf.

Fig. 4 is a detection spectrum in the case where no leakage occurs.

FIG. 5 is a detection spectrum in the case of occurrence of a leak.

Wherein the reference numerals are specified as follows: the device comprises a test pipeline 1, an air compressor 2, a DAS host 3, a leakage hole 4, a pressure gauge 5, a switch valve 6, an optical fiber protection pipe 7, an optical fiber support 8, an external detection optical fiber 9, an internal detection optical fiber 10, a connecting hose 11, a pipeline support 12, a base 13, a connecting rod 14 and a parallel rod 15.

Detailed Description

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

As shown in fig. 1 and fig. 2, the present embodiment provides a gas leakage detection device based on DAS system, which includes a test pipeline 1, a pipeline bracket 12, an external detection optical fiber 9, an internal detection optical fiber 10, an optical fiber protection tube 7, an optical fiber bracket 8, a pressurization mechanism and a pressure detection mechanism, wherein the test pipeline 1 is installed on the pipeline bracket 12, the test pipeline 1 is provided with leakage holes 4, and the number of the leakage holes 4 is 3 and the aperture is different. The optical fiber support 8 is arranged along the test pipeline 1, the external detection optical fiber 9 is placed on the optical fiber support 8, the setting height of the external detection optical fiber 9 is the same as the axial height of the test pipeline 1, one end of the external detection optical fiber is connected with the DAS host 3, and the other end of the external detection optical fiber is connected with the internal detection optical fiber 10. An optical fiber protection tube 7 is fixed in the test pipeline 1, the optical fiber protection tube 7 is a PE tube, the optical fiber protection tube 7 is communicated with the outside, the internal detection optical fiber 10 is arranged in the optical fiber protection tube 7, and one end of the test pipeline 1 is connected with a pressurizing mechanism and a pressure detection mechanism.

As shown in fig. 3, the fiber holder 8 includes a base 13, a connecting rod 14, and a parallel rod 15, and the parallel rod 15 is connected to the base 13 through the connecting rod 14. The height of the optical fiber support 8 is 1m consistent with the central axial height of the position of the test pipeline 1, the length of the base 13 is 0.1m, the length of the parallel rod 15 is 0.3m, and the distance between the external detection optical fiber 9 and the test pipeline 1 is 0.05 m.

The pressurizing mechanism comprises an air compressor 2, a connecting hose 11 and a switch valve 6, the air compressor 2 is connected with one end of the test pipeline 1 through the connecting hose 11, and the switch valve 6 is installed on the connecting hose 11. The pressure detection mechanism is a pressure gauge 5, and the pressure gauge 5 is mounted on the connection hose 11. The pressurizing mechanism is responsible for pressurizing or depressurizing the entire test tube 1 with compressed air.

The method comprises the steps that when gas leaks, the intensity and the phase of backward Rayleigh scattering light in a detection optical fiber are changed, a sensing signal is collected by a data collection module and is transmitted to a computer for processing, a direct current signal is removed, a window function is added and FFT is carried out, a time domain signal and a frequency domain signal are obtained, and whether the gas leaks or not is judged according to the amplitude of the time domain signal before and after the gas leaks and the frequency change leakage characteristic. And simultaneously, determining the position of the leakage by adopting an OTDR technology, and calculating the distance, namely the position of the gas leakage according to the time from transmitting the signal to returning the signal, the refractive index of the optical fiber and the speed of light in the glass substance. The accuracy of the test of the method can be judged by comparing the calculated position with the actually measured position.

In the actual test process, as shown in fig. 4 and 5, the DAS signals that have not leaked or leaked have a horizontal axis of position, a vertical axis of time, and a shade of color of the DAS sensing signals.

Fig. 4 shows DAS signals when no gas leakage occurs, and fig. 5 shows DAS signals when gas leakage occurs. Fig. 5 shows that the DAS signal intensity is much higher when the pipe leaks than when the pipe does not leak, and the leak position is near 4250 meters as can be seen by OTDR technique.

The utility model discloses an experimental method can accurately detect whether gaseous takes place to leak and reveals the position, has the advantage that the monitoring precision is high, response speed is fast. And the gas leakage amount or the leakage caliber can be calculated by further analyzing the acquired data, so that reference is provided for the maintenance work of the pipeline.

Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that modifications or improvements based on the disclosure of the present invention can be made without departing from the spirit and scope of the present invention, and these modifications and improvements are within the spirit and scope of the present invention.

Claims

1. The gas leakage detection device based on the DAS system is characterized by comprising a test pipeline (1), a pipeline support (12), an external detection optical fiber (9), an internal detection optical fiber (10), an optical fiber protection tube (7), an optical fiber support (8), a pressurizing mechanism and a pressure detection mechanism, wherein the test pipeline (1) is installed on the pipeline support (12), a leakage hole (4) is formed in the test pipeline (1), the optical fiber support (8) is arranged along the test pipeline (1), the external detection optical fiber (9) is placed on the optical fiber support (8), one end of the external detection optical fiber is connected with a DAS host (3), the other end of the external detection optical fiber is connected with the internal detection optical fiber (10), an optical fiber protection tube (7) is fixed in the test pipeline (1), the optical fiber protection tube (7) is communicated with the outside, and the internal detection optical fiber (10) is arranged in the optical fiber protection tube (7), one end of the test pipeline (1) is connected with a pressurizing mechanism and the pressure detection mechanism.

2. The DAS system-based gas leak detection apparatus according to claim 1, wherein the optical fiber protection tube (7) is a PE tube.

3. The DAS system-based gas leak detection apparatus according to claim 1, wherein the pressurization mechanism includes an air compressor (2), a connection hose (11), and an on-off valve (6), the air compressor (2) is connected to one end of the test pipe (1) through the connection hose (11), and the on-off valve (6) is mounted on the connection hose (11).

4. A DAS system-based gas leak detection apparatus according to claim 3, wherein the pressure detection mechanism is a pressure gauge (5), and the pressure gauge (5) is mounted on the connection hose (11).

5. A DAS system-based gas leak detection apparatus according to claim 1, wherein the external detection fiber (9) is installed at the same height as the axial height of the test tube (1).

6. A DAS system-based gas leak detection apparatus according to claim 1, wherein the fiber support (8) comprises a base (13), a connection rod (14), and a parallel rod (15), the parallel rod (15) is connected to the base (13) through the connection rod (14).

7. A gas leak detector apparatus according to claim 1, where the number of the leak holes (4) is 3, and the diameters of the 3 leak holes (4) are different.