Sensor devices for gas leak detection

Abstract

The present invention discloses a sensor device for gas leakage detection, which belongs to the field of gas leakage detection. The sensor device includes an N×N type optical fiber splitter / combiner, two Faraday reflectors, and multiple transmission optical fibers; the Faraday reflector is connected to the optical splitter / combiner through the corresponding transmission optical fiber; the optical fiber splitter / combiner is used to receive the light source to be interfered, and split the light source to be interfered into multiple sub-light sources, and then transmit each sub-light source to the corresponding Faraday reflector; the Faraday reflector is used to reflect the sub-light source to the optical fiber splitter / combiner when no gas leakage occurs in the pipeline to be monitored, and when gas leakage occurs in the monitoring pipeline, the sub-light source modulated by the ultrasonic wave generated by the gas leakage is reflected to the optical fiber splitter / combiner; the optical fiber splitter / combiner is also used to make the multiple sub-light sources reflected by the Faraday reflector and the modulated sub-light sources form the first interference light wave signal and the second interference light wave signal respectively.

Description

Technical Field

[0001] The invention relates to the field of gas leakage detection, and in particular to a sensor device for gas leakage detection. Background Art

[0002] The aboveground gas pressure pipelines in areas such as natural gas pipeline stations and shale gas production well platforms are easily affected by factors such as welding construction quality, corrosion, and pipe quality, which may lead to natural gas leakage. Therefore, it is necessary to provide a sensor device for gas leakage detection.

[0003] The prior art provides a sensor device for gas leakage detection, which determines whether a natural gas leakage occurs in the above-mentioned area according to the concentration of natural gas in the air.

[0004] The inventors found that the prior art has at least the following problems:

[0005] The sensor device for gas leakage detection provided by the prior art is easily affected by air flow, resulting in missed reports and low accuracy. Summary of the invention

[0006] The embodiment of the present invention provides a sensor device for gas leakage detection, which can solve the above problems. The technical solution is as follows:

[0007] A sensing device for gas leakage detection is provided, the sensing device comprising: an N×N type optical fiber splitter / combiner, two Faraday reflectors, and a plurality of transmission optical fibers;

[0008] Each of the Faraday reflectors is connected to the beam splitting / combining end of the optical beam splitter / combiner through the corresponding transmission optical fiber;

[0009] The optical fiber splitter / combiner is used to receive the light source to be interfered, and split the light source to be interfered into multiple sub-light sources, and then transmit each sub-light source to the corresponding Faraday reflector;

[0010] The Faraday reflector is used to reflect the sub-light source into the optical fiber splitter / combiner when no gas leakage occurs in the pipeline to be monitored, and to reflect the sub-light source modulated by the ultrasonic wave generated by the gas leakage into the optical fiber splitter / combiner when gas leakage occurs in the monitoring pipeline;

[0011] The optical fiber splitter / combiner is also used to make the multiple sub-light sources reflected by the Faraday reflector and the modulated sub-light sources form a first interference light wave signal and a second interference light wave signal respectively.

[0012] In a possible design, a sensitivity enhancement component is provided on at least one of the transmission optical fibers.

[0013] In a possible design, the sensitizing element includes: a sensitizing cylinder, and a sensitive optical fiber arranged on the sensitizing cylinder;

[0014] The first end and the second end of the sensitive optical fiber are both connected to the corresponding transmission optical fiber.

[0015] In a possible design, the sensitive optical fiber is a bend-insensitive single-mode optical fiber.

[0016] In a possible design, the sensor device further includes: a dust protection cover;

[0017] The sensitizing component is located in the dustproof protective cover.

[0018] In a possible design, a plurality of through holes are provided on the wall of the dustproof protective cover.

[0019] In a possible design, at least one of the transmission optical fibers is provided with a delay optical fiber.

[0020] In a possible design, the delay optical fiber is a single-mode optical fiber.

[0021] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0022] The sensor device for gas leakage detection provided in the embodiment of the present invention can utilize the principle of ultrasonic wave generated by gas leakage to effectively detect whether leakage occurs in the ground pipeline through the cooperation of the optical fiber splitter / combiner, the Faraday reflector and the transmission optical fiber, thereby avoiding the susceptibility of the prior art to the influence of air flow, and has the characteristics of high sensitivity, low false alarm rate and low missed alarm rate, and also has the characteristics of resistance to polarization fading and phase fading. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 is a structural schematic diagram of a sensor device for gas leakage detection provided by an embodiment of the present invention;

[0025] Figure 2 is a schematic structural diagram of a sensitizing component provided in an embodiment of the present invention;

[0026] Figure 3 It is a schematic structural diagram of another type of sensor device for gas leakage detection provided by an embodiment of the present invention.

[0027] The descriptions of the various reference numerals in the accompanying drawings are as follows:

[0028] 1- Fiber splitter / combiner;

[0029] 2-Faraday mirror;

[0030] 3- Transmission optical fiber;

[0031] 4- Sensitization parts;

[0032] 41-sensitization cylinder;

[0033] 42-sensitive optical fiber;

[0034] 5- Dust protection cover;

[0035] 6- Delayed fiber. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] The embodiment of the present invention provides a sensor device for gas leakage detection, as shown in the attached Figure 1 As shown, the sensing device includes: an optical fiber splitter / combiner 1, a plurality of Faraday reflectors 2, and a plurality of transmission optical fibers 3; each Faraday reflector 2 is connected to the splitting / combining end of the optical fiber splitter / combiner 1 through the corresponding transmission optical fiber 3; the optical fiber splitter / combiner 1 is used to receive the light source to be interfered, and split the light source to be interfered into multiple sub-light sources, and then transmit each sub-light source to the corresponding Faraday reflector 2; the Faraday reflector 2 is used to reflect the sub-light source to the optical fiber splitter / combiner 1; the optical fiber splitter / combiner 1 is also used to enable the multiple sub-light sources to generate a first interference light wave signal when no gas leakage occurs in the area to be monitored, and to enable the multiple sub-light sources to generate a second interference light wave signal using the ultrasonic wave generated by the gas leakage when gas leakage occurs in the area to be monitored, and output the first interference light wave signal and the second interference light wave signal.

[0038] The working principle of the sensor device for gas leakage detection provided by the embodiment of the present invention is described below:

[0039] When used, the sensor device is first installed in the gas leakage detection area. Then, the light source to be interfered is received by the light beam splitter / combiner 1, and the light source to be interfered is split into multiple light sources, and then each light source is transmitted to the corresponding Faraday reflector 2 through the corresponding transmission optical fiber 3.

[0040] Afterwards, when no gas leakage occurs in the monitored area, the Faraday reflector 3 is used to reflect the sub-light source toward the optical splitter / combiner 1, so that the sub-light sources reflected by the Faraday reflector 3 are combined in the optical splitter / combiner 1 and interfere with each other, thereby forming a first interference light wave signal.

[0041] Similarly, when a gas leak occurs in the monitored area, multiple sub-light sources first form a first interference light wave signal in the optical splitter / combiner 1, and then the ultrasonic wave generated by the gas leakage acts on the transmission optical fiber 3, causing the transmission optical fiber 3 to vibrate and modulate the phase of the first interference light wave signal, so that the first interference light wave signal forms a second interference light wave signal.

[0042] Finally, the optical beam splitter / combiner 1 is used to transmit the first interference light wave signal or the second interference light wave signal to relevant equipment, and the relevant equipment determines whether a gas leak occurs in the monitored area based on the received interference light wave signal.

[0043] It can be seen that the sensing device for gas leakage detection provided by the embodiment of the present invention, through the cooperation of the optical fiber splitter / combiner 1, the Faraday reflector 2 and the transmission optical fiber 3, can utilize the principle of gas leakage to generate ultrasonic waves to effectively detect whether there is leakage in the ground pipeline, and can avoid the prior art being easily affected by air flow. It has the characteristics of high sensitivity, low false alarm rate, low missed alarm rate, and also has the characteristics of resistance to polarization fading and phase fading.

[0044] In order to facilitate the formation of the first interference light wave signal and the second interference light wave signal by the plurality of sub-light sources in the optical beam splitter / combiner 1, in the embodiment of the present invention, as shown in the attached Figure 1 As shown, two Faraday reflectors 2 are provided.

[0045] It can be understood that the two sub-light sources form a first interference light wave signal and a second interference light wave signal in the optical splitter / combiner 1 .

[0046] The Faraday reflector 2 can be purchased, for example, through Feibot Optoelectronics Technology (Shenzhen) Co., Ltd.

[0047] The above-mentioned optical beam splitter / combiner 1 can not only split the light source, but also combine multiple light paths. If the multiple light paths meet the conditions for interference, interference light waves can be formed in the optical beam splitter / combiner 1.

[0048] The optical beam splitter / combiner 1 can be purchased, for example, from Feibot Optoelectronics Technology (Shenzhen) Co., Ltd.

[0049] The optical splitter / combiner 1 may be an N×N type optical splitter / combiner, that is, the first end and the second end of the optical splitter / combiner 1 of this type are each provided with N optical fibers. In order to increase the intensity of the first interference light wave signal and the second interference light wave signal, N is greater than 2, for example, set to 3, 4, 5, 6, etc.

[0050] Based on the above-mentioned type of optical beam splitter / combiner 1, as shown in the attached Figure 1 As shown, the first end of the optical splitter / combiner 1 is connected to a device for emitting a light source to be interfered (e.g., a laser) through an optical fiber, and the remaining (N-1) optical fibers are connected to other related devices (e.g., a photoelectric conversion module). In addition, the second end of the optical splitter / combiner 1 is connected to two corresponding Faraday reflectors 2 through two optical fibers, and the remaining (N-2) optical fibers do not need to be connected, wherein the two optical fibers are equivalent to the two transmission optical fibers 3 located between the two Faraday reflectors 2 and the optical splitter / combiner 1.

[0051] In order to improve the sensitivity of the sensor device, in the embodiment of the present invention, as shown in the attached Figure 1 As shown, at least one transmission optical fiber 3 is provided with a sensitivity enhancement component 4 .

[0052] Regarding the number of the sensitizing elements 4, multiple sensitizing elements 4 may be arranged at intervals on the same transmission optical fiber 3 to further improve the sensitivity of the sensor device. For example, three sensitizing tubes may be arranged on each transmission optical fiber 3.

[0053] Regarding the structure of the sensitivity enhancing element 4, based on the premise of simple structure, the embodiment of the present invention provides an example, as shown in the attached Figure 2 As shown, the sensitizing element 4 includes: a sensitizing cylinder 41 , and a sensitive optical fiber 42 arranged on the sensitizing cylinder 41 ; the first end and the second end of the sensitive optical fiber 42 are both connected to the corresponding transmission optical fiber 3 .

[0054] The above-mentioned sensitizing cylinder 41 can be prepared by aluminum foil. This type of sensitizing cylinder 41 has the characteristic of being easily vibrated when subjected to ultrasonic waves, which can further increase the sensitivity of the sensitizing element 4 to ultrasonic waves.

[0055] Among them, the thickness of the sensitizing cylinder 41 can be set to 0.1mm~0.15mm. For example, it can be set to 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, etc. The embodiment of the present invention does not impose specific restrictions on the thickness of the sensitizing cylinder 41, as long as it can effectively increase the sensitivity of the sensitizing component 4.

[0056] In addition, the diameter of the sensitization cylinder 41 can be set to 5 cm to 6 cm, for example, 5 cm, 5.5 cm, 6 cm, etc. By setting in this way, it is convenient to produce the sensitization cylinder 41 and it can also ensure that the sensitization cylinder 41 has a certain strength.

[0057] The above-mentioned sensitive optical fiber 42 can be arranged on the sensitizing cylinder 41 in a winding manner. By so arranging, the length of the sensitive optical fiber 42 can be increased, thereby increasing the area where the ultrasonic wave acts on the sensitive optical fiber 42, and further increasing the sensitivity of the sensitizing component 4 to the ultrasonic wave.

[0058] The sensitive optical fiber 42 and the transmission optical fiber 3 can be single-mode optical fibers. Such sensitive optical fibers 42 and transmission optical fibers 3 have the characteristics of low light attenuation and low noise.

[0059] Furthermore, the sensitive optical fiber 42 may be a bend-insensitive single-mode optical fiber, which can avoid light attenuation of the sensitive optical fiber 42 on the sensitivity-enhancing cylinder 41 .

[0060] In order to prevent the sensitizing element 4 from being damaged by the external environment, in the embodiment of the present invention, as shown in the attached Figure 1 , Attachment Figure 2 As shown, the sensor device further includes: a dustproof protective cover 5; and a sensitizing component 4 located inside the dustproof protective cover 5.

[0061] By such an arrangement, the sensitizing component 4 can be prevented from being corroded by rain, snow, wind and sand, etc., so as to extend the service life of the sensitizing component 4.

[0062] In order for the ultrasonic wave generated by the gas leakage to act on the sensitizing element 4, a plurality of through holes are provided on the side wall of the dust protection cover 5 or the side wall is configured to be a mesh structure.

[0063] In addition, the dustproof protective cover 5 may be configured as a barrel-shaped structure, and the embodiment of the present invention does not limit the structure of the dustproof protective cover 5 .

[0064] Since the difference in arm lengths corresponding to each optical circuit in the sensor device (i.e., the optical path between each Faraday reflector 2 and the optical beam splitter / combiner 1) is larger, the noise generated by the sensor device is larger. Therefore, in the embodiment of the present invention, as shown in the attached Figure 1 As shown, at least one transmission optical fiber 3 is provided with a delay optical fiber 6 to reduce the arm error of the sensing device.

[0065] Since the arm length corresponding to each optical circuit is related to the optical path of each optical circuit, the length of the delay optical fiber 6 can be set according to the total length of the optical fiber (including the transmission optical fiber 3 and the sensitive optical fiber 42) corresponding to each optical circuit.

[0066] For example, if Figure 3As shown, the sensing device includes two Faraday reflectors 2, that is, the sensing device includes an optical circuit 1 and an optical circuit 2. Two sensitizers 4 are arranged on the optical circuit 1, and four sensitizers 4 are arranged on the optical circuit 2, and each sensitizer 4 is wound with a 50m sensitive optical fiber 42; in addition, the transmission optical fiber 3 on the optical circuit 1 and the optical circuit 2 is 100m long. Then, in order to compensate for the arm difference between the optical circuit 1 and the optical circuit 2, a delay optical fiber 6 with a length of 98m can be arranged on the optical circuit 1.

[0067] Based on the above-mentioned length of the delay optical fiber 6, in order to facilitate the installation of the delay optical fiber 6, the delay optical fiber 6 can be wound on a fiber coil.

[0068] In addition, the above-mentioned delay optical fiber 6 can be a single-mode optical fiber. This type of delay optical fiber 6 has the characteristics of small light attenuation and small noise.

[0069] It is understandable that the delay optical fiber 6, the Faraday reflector 2, and the optical fiber splitter / combiner 1 can also be installed in the dustproof protective cover 5 (see the attached Figure 3 ).

[0070] Based on the above-mentioned sensor device, in order to ensure that the sensor device has excellent sensitivity, in the embodiment of the present invention, as shown in the attached Figure 1 As described above, each transmission optical fiber 3 corresponding to the Faraday reflector 2 is provided with a delay optical fiber 6 and a plurality of sensitivity enhancement components 4 .

[0071] In the embodiment of the present invention, in order to protect the transmission optical fiber 3 located outside the dust protection cover 4, a protective layer can be covered on the outside of the transmission optical fiber 3 to form an optical cable (see the attached Figure 3 Thickness bars shown).

[0072] In summary, the sensor device for gas leakage detection provided by the embodiment of the present invention has been actually used and tested in natural gas stations, and can fully cover an area of ​​20m×70m, can effectively monitor gas leakage, and has the characteristics of high sensitivity, accurate alarm, and low cost compared to other monitoring methods. In addition, the multiple sensitization components 21 are connected through the transmission optical fiber 3, which has the characteristics of convenient and simple layout and free layout position.

[0073] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present disclosure, and will not be described in detail here.

[0074] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sensing device for gas leak detection, characterized in that: The sensing device comprises: an N×N type optical beam splitter / combiner (1), two Faraday reflectors (2), and a plurality of transmission optical fibers (3); Each of the Faraday reflectors (2) is connected to the beam splitting / combining end of the optical beam splitter / combiner (1) via the corresponding transmission optical fiber (3); The optical beam splitter / combiner (1) is used to receive a light source to be interfered with, and split the light source to be interfered with into multiple sub-light sources, and then transmit each sub-light source to the corresponding Faraday reflector (2); The Faraday reflector (2) is used to reflect the sub-light source into the light beam splitter / combiner (1); The optical beam splitter / combiner (1) is also used to enable the plurality of sub-light sources to generate a first interference light wave signal when no gas leakage occurs in the area to be monitored, and to enable the plurality of sub-light sources to generate a second interference light wave signal using ultrasonic waves generated by the gas leakage when gas leakage occurs in the area to be monitored, and to output the first interference light wave signal and the second interference light wave signal; Wherein, at least one of the transmission optical fibers (3) is provided with a sensitivity enhancement component (4) and a delay optical fiber (6); The sensitivity enhancement component (4) comprises: a sensitivity enhancement cylinder (41), and a sensitive optical fiber (42) arranged on the sensitivity enhancement cylinder (41); the first end and the second end of the sensitive optical fiber (42) are both connected to the corresponding transmission optical fiber (3); the sensitive optical fiber (42) is a bending-insensitive single-mode optical fiber; The sensing device further comprises: a dustproof protective cover (5); the delay optical fiber (6), the Faraday reflector (2), the optical beam splitter / combiner (1) and the sensitivity enhancement component (4) are all located inside the dustproof protective cover (5).

2. The sensor device according to claim 1, characterized in that A plurality of through holes are provided on the wall of the dustproof protective cover (5).

3. The sensor device according to claim 1, characterized in that: The side wall of the dustproof protective cover (5) is configured as a mesh structure.

4. The sensor device according to claim 1, characterized in that The delay optical fiber (6) is a single-mode optical fiber.

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