Low-temperature alarm device and alarm method for gas transmission pipeline leakage

Abstract

The present invention relates to a low-temperature alarm device and alarm method for gas transmission pipeline leakage. It solves the problems of poor accuracy and easy false alarms and non-alarms in the existing pipeline leakage detection system. It includes a gas transmission pipeline, an assembly outer pipe is sleeved on the circumferential outer side of the gas transmission pipeline, and there is an assembly gap between the assembly outer pipe and the gas transmission pipeline. An annular temperature measurement kit sleeved on the circumferential outer side of the gas transmission pipeline is arranged in the assembly gap, and a plurality of optical fiber temperature measurement mechanisms covering the outer wall of the gas transmission pipeline are arranged at both ends of the annular temperature measurement kit. A protective outer pipe is sleeved on the circumferential outer side of the assembly outer pipe, and there is a constant-pressure gap between the protective outer pipe and the assembly outer pipe. A pressure alarm device that can automatically give an alarm when the air pressure in the constant-pressure gap changes is arranged in the constant-pressure gap. The annular temperature measurement kit and the pressure alarm device are signal-connected to a low-temperature alarm platform. The advantages of the present invention are: good detection accuracy, not easy to generate false alarms, and good use effect.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline leakage detection, and particularly to a low-temperature alarm device and an alarm method for gas transmission pipeline leakage. Background Art

[0002] Pipeline transportation has unique advantages in crude oil transportation and has become the fifth major means of transportation after railway, highway, waterway, and air transportation. Due to inevitable aging, corrosion, and oil theft by drilling, pipeline leakage occurs frequently, seriously interfering with normal production and causing huge economic losses and environmental pollution. Therefore, pipeline leakage detection and positioning systems are of great practical significance for timely discovering pipeline leakage, combating oil theft, protecting the environment, and reducing economic losses. Currently, the technologies for pipeline leakage monitoring and leakage location mainly include: negative pressure wave leakage monitoring system, infrasound leakage monitoring system, leakage monitoring system based on distributed optical fiber temperature, etc. Among them, although the distributed optical fiber temperature sensing system can monitor pipeline leakage, it is not suitable for leakage monitoring of pipelines with low temperature difference, and the difference in the relative position between the optical fiber and the pipeline in engineering will also affect the judgment of leakage events and location positioning; in addition, the existing distributed optical fiber temperature sensing system is prone to false alarms, with poor monitoring accuracy, and it is difficult for the pipeline leakage detection method to detect leakage when the temperature decreases slowly, prone to missed alarms and untimely alarms, and there are loopholes in the detection method.

[0003] In order to solve the deficiencies of the existing technology, people have carried out long-term explorations and proposed various solutions. For example, a Chinese patent document discloses a distributed optical fiber multi-parameter pipeline leakage location alarm system and a leakage location method [CN201810599694.3], which includes a sensing optical fiber laid in the same trench as the pipeline, a DTS system connected to the sensing optical fiber, at least two groups of negative pressure wave monitoring devices are provided on the pipeline, the negative pressure wave monitoring system and the DTS system are both connected to the monitoring center through communication interfaces and Ethernet, the negative pressure wave monitoring device includes a pressure flow transmitter connected to the pipeline, the pressure flow transmitter is connected to a data collector, and the data collector is connected with a GPS timing antenna.

[0004] The above solution solves to a certain extent the problem that it is difficult to monitor leakage in the existing pipeline leakage detection system at low temperature difference, but this solution still has many deficiencies, such as: the monitoring system is prone to false alarms, with poor detection accuracy, and it is difficult to detect pipeline leakage when the temperature decreases slowly, prone to missed alarms and untimely alarms, and there are loopholes in the detection method. Summary of the Invention

[0005] The object of the present invention is to provide a gas transmission pipeline leakage low-temperature alarm device with reasonable design and good detection accuracy for the above problems.

[0006] The object of the present invention is to provide a low-temperature alarm method for gas pipeline leakage with reasonable design and good detection method in view of the above problems.

[0007] To achieve the above object, the present invention adopts the following technical solutions: This low-temperature alarm device for gas pipeline leakage includes a gas pipeline. An assembly outer pipe is sleeved on the circumferential outer side of the gas pipeline, and there is an assembly gap between the assembly outer pipe and the gas pipeline. An annular temperature measurement kit sleeved on the circumferential outer side of the gas pipeline is arranged in the assembly gap, and a number of optical fiber temperature measurement mechanisms covering the outer wall of the gas pipeline are arranged at both ends of the annular temperature measurement kit. A protective outer pipe is sleeved on the circumferential outer side of the assembly outer pipe, and there is a constant-pressure gap between the protective outer pipe and the assembly outer pipe. A pressure alarm device that can automatically give an alarm when the air pressure in the constant-pressure gap changes is arranged in the constant-pressure gap. The annular temperature measurement kit and the pressure alarm device are signal-connected to the low-temperature alarm platform. By arranging an annular temperature measurement kit on the circumferential outer side of the gas pipeline to detect the temperature of the assembly gap and using the optical fiber temperature measurement mechanism to detect the surface temperature of the gas pipeline, when gas leakage occurs in the gas pipeline, the temperature of the assembly gap and the outer wall temperature of the gas pipeline change, and since the air pressure in the constant-temperature gap increases during leakage, the pressure alarm device can be triggered, so that it is possible to accurately judge whether there is a leakage situation, and the detection accuracy is good.

[0008] In the above low-temperature alarm device for gas pipeline leakage, the annular temperature measurement kit includes two annular kits sleeved on the circumferential outer side of the gas pipeline. A number of temperature measurement cross bars arranged circumferentially along the gas pipeline are arranged between the annular kits, and there is no contact between the circumferential inner wall of the temperature measurement cross bar and the circumference of the gas pipeline. An insulating rubber strip is arranged on the circumferential inner side of the annular kit, and the insulating rubber strip is in contact with the circumference of the gas pipeline. The insulating rubber strip can prevent the annular kit from being affected by the temperature of the gas pipeline, and the temperature measurement cross bar can detect the circumferential temperature of the assembly gap, and the use effect is good.

[0009] In the above low-temperature alarm device for gas pipeline leakage, adjacent gas pipelines are connected by a connecting disk body. The circumferential direction of the connecting disk body is covered by the above protective outer pipe, and the inner wall of the protective outer pipe is closely attached to the outer wall of the circumferential direction of the connecting disk body, so as to form a barrier for the constant-pressure gap between the two adjacent assembly outer pipes. The two ends of the assembly outer pipe are respectively inserted into the inner cavity of the corresponding connecting disk body, and the gas pipeline radially penetrates through the connecting disk body. After the constant-pressure gap forms a barrier, it can prevent the gas from dispersing when the gas pipeline leaks, resulting in delayed alarm or non-alarm.

[0010] In the above-mentioned low-temperature alarm device for gas pipeline leakage, the optical fiber temperature measurement mechanism includes an arc-shaped optical fiber tube body with one end circumferentially arranged on the outer circumference of the gas pipeline. A temperature measurement optical fiber is arranged inside the arc-shaped optical fiber tube body, and a number of heat conduction structures are connected to the temperature measurement optical fiber and are axially distributed along the inner wall of the arc-shaped optical fiber tube body. One end of the heat conduction structure is in contact with the outer wall of the gas pipeline, and the other end is connected to the temperature measurement optical fiber. The heat conduction structures are arranged in a staggered manner on the inner wall of the arc-shaped optical fiber tube body. The setting of the optical fiber temperature measurement mechanism performs circumferential temperature measurement on the gas pipeline, and can accurately determine the leakage point position.

[0011] In the above-mentioned low-temperature alarm device for gas pipeline leakage, one end of the arc-shaped optical fiber tube body is provided with a plug-in connection conductor. A number of arc-shaped connection grooves for the plug-in connection conductor to be inserted are provided on the annular kit. The end of the plug-in connection conductor has an electrical connection slot, and one end of the temperature measurement cross bar is provided with a signal connection plug. The signal connection plug is inserted into the electrical connection slot, and positioning slots are provided on both sides of the arc-shaped optical fiber tube body. Positioning blocks corresponding to the positioning slots are provided in the arc-shaped connection grooves. When the plug-in connection conductor is inserted into the corresponding arc-shaped connection groove, the positioning blocks are inserted into the positioning slots. Such a setting facilitates the low-temperature alarm platform to determine the position of the leakage point, and the search and repair are more convenient.

[0012] In the above-mentioned low-temperature alarm device for gas pipeline leakage, a signal connection line is provided on the circumferential inner wall of the annular kit. Both ends of the signal connection line are respectively connected to the positioning blocks, and a signal sending module and a positioning module are provided on the signal connection line. Signals are transmitted between the signal sending module and the positioning module and the low-temperature alarm platform; the heat conduction structure includes a temperature induction head, and the temperature induction head is arranged on a universal rotating seat on the arc-shaped optical fiber tube body, and a signal connection is provided between the temperature induction head and the temperature measurement optical fiber.

[0013] In the above-mentioned low-temperature alarm device for gas pipeline leakage, the pressure alarm device includes a pressure measurement frame body arranged in the constant pressure gap. A top pressure cavity is provided inside the pressure measurement frame body, and an air inlet hole communicating with the top pressure cavity is provided at the bottom of the pressure measurement frame body. A top pressure slider is provided in the top pressure cavity, and a connection chute for the top pressure slider to slide up and down is provided on the outer wall of the protective outer tube. The upper end of the connection chute is closed by a circuit board, and a start switch is provided on one side of the circuit board close to the top pressure slider. The circuit board and the connection chute are closed by a sealing frame body, and an audible and visual alarm electrically connected to the circuit board is provided on the sealing frame body. An external temperature sensor is provided on one side of the audible and visual alarm. When the gas pipeline leaks, the air pressure in the constant temperature gap increases, generating a thrust at the bottom of the top pressure slider to trigger the start switch, and the linkage effect is good.

[0014] According to the above-mentioned low-temperature alarm device for gas pipeline leakage, a low-temperature alarm method for gas pipeline leakage is provided. This method includes the following steps:

[0015] S1. Set the cooling threshold value in the assembly gap when the gas pipeline leaks through the low-temperature alarm platform;

[0016] S2. Perform low-temperature detection on the assembly gap through the annular temperature measurement kit arranged on the circumferential outer side of each section of the gas transmission pipeline, and at the same time detect the temperature of the circumferential outer wall of the gas transmission pipeline by using the optical fiber temperature measurement mechanism;

[0017] S3. Detect the air pressure in the constant pressure gap through the pressure alarm device,

[0018] S4. Use the low-temperature detection platform for low-temperature monitoring and determine whether the transmission pipeline leaks.

[0019] In step S1, when setting the cooling threshold, record the internal and external temperature differences in 1 - 2 days respectively through the external temperature sensor and the temperature sensing head, and the set cooling threshold is greater than the threshold of the temperature difference change. Such a setting can avoid false alarms in scenarios with large day-night temperature differences.

[0020] In step S4, the determination rule for pipeline leakage is that the low-temperature threshold in the assembly gap is greater than the pre-set cooling threshold, and the temperature in the assembly gap is compared with the temperatures in the assembly gaps on the circumferential outer sides of two adjacent transmission pipelines through the annular temperature measurement kit. If the temperature difference is greater than the set cooling threshold, it is determined that this section of the transmission pipeline leaks; when the transmission pipeline leaks, the positioning module sends location information to the low-temperature alarm platform, and the pressure in the constant pressure gap increases, causing the top pressure slider to slide and press the start switch to trigger the sound and light alarm. Through reasonable horizontal comparison and the threshold of temperature change for accurate judgment, it can effectively avoid false alarms or non-alarms when the gas transmission pipeline leaks.

[0021] Compared with the existing technology, the advantages of the present invention are as follows: reasonable design, simple method. By arranging an annular temperature measurement kit on the circumferential outer side of the gas transmission pipeline to detect the temperature of the assembly gap, and using the optical fiber temperature measurement mechanism to detect the surface temperature of the gas transmission pipeline, the low-temperature alarm platform sets the low-temperature alarm threshold according to the day-night temperature difference. When the detected temperature threshold is greater than the set low-temperature alarm threshold, the low-temperature alarm platform makes a horizontal comparison of the temperature thresholds of two adjacent assembly gaps. If the temperature threshold difference is greater than the pre-set threshold difference, an alarm is issued through the low-temperature alarm platform, so as to accurately judge whether there is a leakage situation, with good detection accuracy. At the same time, when the gas transmission pipeline has a gas leak, the air pressure in the constant temperature gap increases, which can independently trigger the pressure alarm device on the corresponding gas transmission pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the overall structural cross-sectional view of the present invention;

[0023] Figure 2 is Figure 1 the enlarged view of the structure at A in

[0024] Figure 3 It is a schematic structural diagram of the annular temperature measurement kit in the present invention;

[0025] Figure 4 It is a schematic structural diagram of the optical fiber temperature measurement mechanism in the present invention;

[0026] Figure 5 It is a cross-sectional view of the annular kit in the present invention;

[0027] Figure 6 It is a schematic structural diagram of the temperature measurement cross bar in the present invention;

[0028] Figure 7 It is a connection block diagram of the local structure in the present invention.

[0029] In the figure, there are gas transmission pipeline 1, assembly outer pipe 11, assembly gap 12, protective outer pipe 13, constant pressure gap 14, connection disc body 15, annular temperature measurement kit 2, annular kit 21, temperature measurement cross bar 22, heat insulation rubber strip 23, signal connection plug 24, optical fiber temperature measurement mechanism 3, arc-shaped optical fiber tube body 31, temperature measurement optical fiber 32, plug-in connection conductor 33, electrical connection slot 34, positioning slot 35, positioning plug 36, arc-shaped connection slot 37, pressure alarm device 4, pressure measurement frame body 41, top pressure cavity 42, air inlet hole 43, top pressure slider 44, connection sliding groove 45, circuit board 46, start switch 47, sealing frame body 48, sound and light alarm 49, external temperature sensor 491, low temperature alarm platform 5, heat conduction structure 6, universal rotating seat 62, signal connection line 7, signal sending module 71, positioning module 72. Specific embodiments

[0030] The following further elaborates on the present invention in detail in conjunction with the accompanying drawings and specific embodiments.

[0031] Such as Figure 1-7As shown in the figure, the low-temperature alarm device for gas pipeline leakage includes a gas pipeline 1. An assembly outer pipe 11 is sleeved on the outer circumference of the gas pipeline 1, and there is an assembly gap 12 between the assembly outer pipe 11 and the gas pipeline 1. An annular temperature measurement kit 2 sleeved on the outer circumference of the gas pipeline 1 is arranged in the assembly gap 12, and a number of optical fiber temperature measurement mechanisms 3 covering the outer wall of the gas pipeline 1 are arranged at both ends of the annular temperature measurement kit 2. A protective outer pipe 13 is sleeved on the outer circumference of the assembly outer pipe 11, and there is a constant pressure gap 14 between the protective outer pipe 13 and the assembly outer pipe 11. A pressure alarm device 4 that can automatically give an alarm when the air pressure in the constant pressure gap 14 changes is arranged in the constant pressure gap 14. The annular temperature measurement kit 2 and the pressure alarm device 4 are signal-connected to the low-temperature alarm platform 5. The annular temperature measurement kit 2 is used to detect the real-time temperature of the assembly gap 12 on the outer circumference of the gas pipeline 1, and the optical fiber temperature measurement mechanism 3 is used to conduct a covering detection of the temperature of the outer wall of the gas pipeline 1. When the gas pipeline 1 leaks, the temperature of the assembly gap 12 changes. When the low-temperature threshold of the assembly gap 12 is greater than the preset low-temperature alarm threshold of the pressure alarm device 4, the two adjacent assembly gaps 12 are horizontally compared. If the difference in the low-temperature thresholds continues to increase and exceeds the maximum difference in the preset low-temperature thresholds, an alarm is issued; and when the gas pipeline 1 leaks, the pressure in the constant pressure gap 14 increases to trigger the pressure alarm device 4. When the pressure alarm device 4 issues an alarm, it sends a leakage signal and location information to the low-temperature alarm platform 5.

[0032] Among them, the annular temperature measurement kit 2 includes two annular kits 21 sleeved on the outer circumference of the gas pipeline 1. A number of temperature measurement cross bars 22 arranged circumferentially along the gas pipeline 1 are arranged between the annular kits 21, and there is no contact between the inner circumference of the temperature measurement cross bar 22 and the circumference of the gas pipeline 1. An insulating rubber strip 23 is arranged on the inner circumference of the annular kit 21, and the insulating rubber strip 23 is in contact with the circumference of the gas pipeline 1. The insulating rubber strip is used to block the temperature influence of the outer wall temperature of the gas pipeline 1 on the annular kit 21, and the temperature measurement cross bar 22 is used to detect the temperature of the assembly detection 12.

[0033] Visibly, two adjacent gas pipelines 1 are connected by a connecting disc body 15. The circumference of the connecting disc body 15 is covered by the above-mentioned protective outer pipe 13, and the inner wall of the protective outer pipe 13 is closely attached to the outer circumference of the connecting disc body 15, so as to block the constant pressure gap 14 between the two adjacent assembly outer pipes 11. Both ends of the assembly outer pipe 11 are inserted into the inner cavity of the corresponding connecting disc body 15, and the gas pipeline 1 radially penetrates through the connecting disc body 15. Such a setting is used to prevent the gas from leaking from the gas pipeline 1 from entering the adjacent constant pressure gap.

[0034] Furthermore, the optical fiber temperature measurement mechanism 3 includes an arc-shaped optical fiber tube body 31 with one end circumferentially arranged on the outer circumference of the gas transmission pipeline 1. A temperature measurement optical fiber 32 is arranged inside the arc-shaped optical fiber tube body 31, and a number of heat conduction structures 6 are connected to the temperature measurement optical fiber 32 and are axially distributed along the inner wall of the arc-shaped optical fiber tube body 31. One end of the heat conduction structure 6 is in contact with the outer wall of the gas transmission pipeline 1, and the other end is connected to the temperature measurement optical fiber 32. The heat conduction structures 6 are arranged in a staggered manner on the inner wall of the arc-shaped optical fiber tube body 31.

[0035] Obviously, one end of the arc-shaped optical fiber tube body 31 is provided with a plug-in connection conductor 33. A number of arc-shaped connection grooves 37 for the plug-in connection conductor 33 to be inserted are arranged on the annular kit 21. The end of the plug-in connection conductor 33 has an electrical connection slot 34, and one end of the temperature measurement cross bar 22 is provided with a signal connection plug 24. The signal connection plug 24 is plugged into the electrical connection slot 34. Positioning slots 35 are arranged on both sides of the arc-shaped optical fiber tube body 31. Positioning blocks 36 corresponding to the positioning slots 35 are arranged in the arc-shaped connection grooves 37. When the plug-in connection conductor 33 is inserted into the corresponding arc-shaped connection groove 37, the positioning block 36 is inserted into the positioning slot 35. The plug-in connection conductor 33 is used to transmit the signal of the temperature measurement optical fiber 32, and the signal connection plug 24 is used to transmit the signal of the temperature measurement cross bar 22. The end of the arc-shaped optical fiber tube body 31 away from the plug-in connection conductor 33 is arranged in the connection disc body 15 through a plug-in part.

[0036] Specifically, a signal connection line 7 is arranged on the circumferential inner wall of the annular kit 21. Both ends of the signal connection line 7 are respectively connected to the positioning blocks 36, and a signal sending module 71 and a positioning module 72 are arranged on the signal connection line 7. Signal transmission is carried out between the signal sending module 71 and the positioning module 72 and the low-temperature alarm platform 5; the heat conduction structure 6 includes a temperature induction head 61. The temperature induction head 61 is arranged on a universal rotating seat 62 on the arc-shaped optical fiber tube body 31, and a signal connection is established between the temperature induction head 61 and the temperature measurement optical fiber 32. The signal sending module 71 is used to send the temperatures of the temperature measurement cross bar 22 and the temperature measurement optical fiber 32 to the low-temperature alarm platform 5, and the positioning module 72 is used to send leakage position information to the low-temperature alarm platform 5 when the gas transmission pipeline 1 leaks.

[0037] Preferably, the pressure alarm device 4 includes a pressure measuring frame body 41 arranged in the constant pressure gap 14. The pressure measuring frame body 41 has a top pressure cavity 42 inside, and the bottom of the pressure measuring frame body 41 has an air inlet hole 43 communicating with the top pressure cavity 42. A top pressure slider 44 is arranged in the top pressure cavity 42, and a connecting sliding groove 45 for the top pressure slider 44 to slide up and down is arranged on the outer wall of the protective outer tube 13. The upper end of the connecting sliding groove 45 is closed by a circuit board 46, and a start switch 47 is arranged on the side of the circuit board 46 close to the top pressure slider 44. The circuit board 46 and the connecting sliding groove 45 are closed by a sealing frame body 48, and an audible and visual alarm 49 electrically connected to the circuit board 46 is arranged on the sealing frame body 48. An external temperature sensor 491 is arranged on one side of the audible and visual alarm 49. When the gas transmission pipeline 1 leaks, the air pressure in the constant pressure gap 14 increases, and the bottom of the top pressure slider 44 is pushed upward to trigger the start switch 47, so that the audible and visual alarm 49 emits an alarm. When the audible and visual alarm 49 emits an alarm, an alarm message is sent to the low-temperature alarm platform 5.

[0038] A method for low-temperature alarm of gas transmission pipeline leakage, the method includes the following steps:

[0039] S1. Set the temperature reduction threshold in the assembly gap 12 when the gas transmission pipeline 1 leaks through the low-temperature alarm platform 5;

[0040] S2. Perform low-temperature detection in the assembly gap 12 through the annular temperature measuring kit 2 arranged on the circumferential outer side of each section of the gas transmission pipeline 1, and at the same time use the optical fiber temperature measuring mechanism 3 to detect the temperature of the circumferential outer wall of the gas transmission pipeline 1;

[0041] S3. Detect the air pressure in the constant pressure gap 14 through the pressure alarm device 4;

[0042] S4. Use the low-temperature detection platform for low-temperature monitoring and determine whether the conveying pipeline leaks.

[0043] In step S1, when setting the temperature reduction threshold, the internal and external temperature differences in 1-2 days are respectively recorded through the external temperature sensor 491 and the temperature sensing head 61, and the set temperature reduction threshold is greater than the threshold of the temperature difference change. This is used to prevent false alarms when the conveying pipe body 1 is in an environment with large day-night temperature differences.

[0044] In step S4, the determination rule for the leakage of the conveying pipeline is that the low-temperature threshold within the assembly gap 12 is greater than the preset temperature reduction threshold, and the temperature within the assembly gap 12 is compared with the temperature within the assembly gaps 12 on the circumferential outer sides of two adjacent conveying pipelines through the annular temperature measurement kit 2. If the temperature difference is greater than the set temperature reduction threshold, it is determined that this section of the conveying pipeline leaks; when the conveying pipeline leaks, the positioning module 72 sends the position information to the low-temperature alarm platform 5, and the pressure in the constant-pressure gap 14 increases, causing the top-pressure slider 44 to slide and press the start switch 47, thereby triggering the sound and light alarm 49.

[0045] In summary, the principle of this embodiment is as follows: The external temperature sensor 491 and the annular temperature measurement kit 2 are used to detect the internal and external temperature difference during a day. The low-temperature alarm platform 5 sets the low-temperature thresholds for each time period within the reasonable assembly gap 12 according to the temperature difference change during a day. The annular temperature measurement kit 2 is used to perform real-time temperature detection on the assembly gap 12 on the circumferential outer side of the gas transmission pipeline 1, and the optical fiber temperature measurement mechanism 3 is used to perform covering detection on the outer wall temperature of the gas transmission pipeline 1. When the gas transmission pipeline 1 leaks, the temperature of the assembly gap 12 changes. When the low-temperature threshold exceeds the set low-temperature alarm threshold, the low-temperature alarm platform 5 makes a horizontal comparison of the temperatures within two adjacent assembly gaps 12. When the difference between the compared low-temperature thresholds is greater than the set temperature threshold difference and continuously changes, it is determined that the gas transmission pipeline 1 leaks. When the gas transmission pipeline 1 leaks, the air pressure in the constant-pressure gap 14 increases, and the bottom of the top-pressure slider 44 is pushed upward to slide and trigger the start switch 47, so that the sound and light alarm 49 issues an alarm. When the sound and light alarm 49 issues an alarm, it sends an alarm message to the low-temperature alarm platform 5.

[0046] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar methods to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0047] Although terms such as gas transmission pipeline 1, assembled outer pipe 11, assembly gap 12, protective outer pipe 13, constant pressure gap 14, connecting disc body 15, annular temperature measuring kit 2, annular kit 21, temperature measuring cross bar 22, heat insulating rubber strip 23, signal connection plug 24, optical fiber temperature measuring mechanism 3, arc-shaped optical fiber tube body 31, temperature measuring optical fiber 32, plug-in connection conductor 33, electrical connection slot 34, positioning slot 35, positioning plug 36, arc-shaped connection slot 37, pressure alarm device 4, pressure measuring frame body 41, top pressure cavity 42, air inlet hole 43, top pressure slider 44, connection chute 45, circuit board 46, start switch 47, sealing frame body 48, sound and light alarm 49, external temperature sensor 491, low temperature alarm platform 5, heat conduction structure 6, universal rotating seat 62, signal connection line 7, signal sending module 71, positioning module 72 are used more frequently in this text, it does not exclude the possibility of using other terms. These terms are only used to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A low-temperature alarm device for gas pipeline leakage, including a gas pipeline (1). An assembly outer pipe (11) is sleeved on the circumferential outer side of the gas pipeline (1), and there is an assembly gap (12) between the assembly outer pipe (11) and the gas pipeline (1). It is characterized in that An annular temperature measurement kit (2) sleeved on the circumferential outer side of the gas transmission pipeline (1) is arranged in the described assembly gap (12). A plurality of optical fiber temperature measurement mechanisms (3) covering the outer wall of the gas transmission pipeline (1) are arranged at both ends of the annular temperature measurement kit (2). A protective outer pipe (13) is sleeved on the circumferential outer side of the assembly outer pipe (11), and a constant pressure gap (14) is provided between the protective outer pipe (13) and the assembly outer pipe (11). A pressure alarm device (4) capable of automatically giving an alarm when the air pressure in the constant pressure gap (14) changes is arranged in the constant pressure gap (14). The annular temperature measurement kit (2) and the pressure alarm device (4) are in signal connection with a low-temperature alarm platform (5); the annular temperature measurement kit (2) includes two annular kits (21) sleeved on the circumferential outer side of the gas transmission pipeline (1). A plurality of temperature measurement cross bars (22) arranged circumferentially along the gas transmission pipeline (1) are arranged between the annular kits (21). No contact is generated between the circumferential inner wall of the temperature measurement cross bar (22) and the circumference of the gas transmission pipeline (1). An insulating rubber strip (23) is arranged on the circumferential inner side of the annular kit (21), and the insulating rubber strip (23) is in contact with the circumference of the gas transmission pipeline (1); adjacent gas transmission pipelines (1) are connected by a connecting disc body (15). The circumferential direction of the connecting disc body (15) is covered by the above-mentioned protective outer pipe (13), and the inner wall of the protective outer pipe (13) is in close fit with the circumferential outer wall of the connecting disc body (15) so as to form a barrier for the constant pressure gap (14) between the two connected assembly outer pipes (11). Both ends of the assembly outer pipe (11) are respectively inserted into the inner cavity of the corresponding connecting disc body (15), and the gas transmission pipeline (1) radially penetrates through the connecting disc body (15); the optical fiber temperature measurement mechanism (3) includes an arc-shaped optical fiber tube body (31) with one end circumferentially arranged on the circumferential outer side of the gas transmission pipeline (1). A temperature measurement optical fiber (32) is arranged in the arc-shaped optical fiber tube body (31). A plurality of heat conduction structures (6) axially distributed along the inner wall of the arc-shaped optical fiber tube body (31) are connected to the temperature measurement optical fiber (32). One end of the heat conduction structure (6) is in contact with the outer wall of the gas transmission pipeline (1), and the other end is connected to the temperature measurement optical fiber (32). The heat conduction structures (6) are arranged in a staggered manner on the inner wall of the arc-shaped optical fiber tube body (31).One end of the arc-shaped optical fiber tube body (31) is provided with a plug-in connection conductor (33). A number of arc-shaped connection grooves (37) for the plug-in connection conductor (33) to be inserted are provided on the annular kit (21). The end of the plug-in connection conductor (33) has an electrical connection slot (34). One end of the temperature measurement cross bar (22) is provided with a signal connection plug (24). The signal connection plug (24) is inserted into the electrical connection slot (34). Positioning slots (35) are provided on both sides of the arc-shaped optical fiber tube body (31). Positioning plugs (36) corresponding to the positioning slots (35) are provided in the arc-shaped connection grooves (37). When the plug-in connection conductor (33) is inserted into the corresponding arc-shaped connection groove (37), the positioning plug (36) is inserted into the positioning slot (35). The heat conduction structure (6) includes a temperature induction head (61). The temperature induction head (61) is arranged on a universal rotating seat (62) on the arc-shaped optical fiber tube body (31). And a signal connection is established between the temperature induction head (61) and the temperature measurement optical fiber (32).; 2. The low-temperature alarm device for gas pipeline leakage according to claim 1 It is characterized in that A signal connecting wire (7) is arranged on the circumferential inner wall of the annular kit (21). The two ends of the signal connecting wire (7) are respectively connected to the positioning plug (36), and a signal sending module (71) and a positioning module (72) are arranged on the signal connecting wire (7). The signal sending module (71) and the positioning module (72) transmit signals to the low-temperature alarm platform (5).

3. The low-temperature alarm device for gas pipeline leakage according to claim 1 It is characterized in that The pressure alarm device (4) includes a pressure measuring frame body (41) arranged in the constant pressure gap (14). There is a top pressure cavity (42) in the pressure measuring frame body (41), and an air inlet hole (43) communicating with the top pressure cavity (42) is arranged at the bottom of the pressure measuring frame body (41). A top pressure slider (44) is arranged in the top pressure cavity (42), and a connecting sliding groove (45) for the top pressure slider (44) to slide up and down is arranged on the outer wall of the protective outer pipe (13). The upper end of the connecting sliding groove (45) is closed by a circuit board (46), and a start switch (47) is arranged on one side of the circuit board (46) close to the top pressure slider (44). The circuit board (46) and the connecting sliding groove (45) are closed by a sealing frame body (48), and an audible and visual alarm (49) electrically connected to the circuit board (46) is arranged on the sealing frame body (48). An external temperature sensor (491) is arranged on one side of the audible and visual alarm (49).

4. The low-temperature alarm method for gas pipeline leakage of the low-temperature alarm device for gas pipeline leakage according to any one of claims 1-3 It is characterized in that This method includes the following steps: S1. Set the temperature reduction threshold in the assembly gap (12) when the gas pipeline (1) leaks through the low-temperature alarm platform (5); S2. Perform low-temperature detection in the assembly gap (12) through the annular temperature measuring kit (2) arranged on the circumferential outer side of each section of the gas pipeline (1), and at the same time use the optical fiber temperature measuring mechanism (3) to detect the temperature of the circumferential outer wall of the gas pipeline (1); S3. Detect the air pressure in the constant pressure gap (14) through the pressure alarm device (4); S4. Use the low-temperature detection platform for low-temperature monitoring and determine whether the conveying pipeline leaks.

5. The low-temperature alarm method for gas pipeline (1) leakage according to claim 4 It is characterized in that, it is characterized in that In step S1, when setting the temperature reduction threshold, the external temperature sensor (491) and the temperature sensing head (61) are used to record the internal and external temperature differences in 1-2 days respectively, and the set temperature reduction threshold is greater than the threshold of the temperature difference change.

6. The low-temperature alarm method for gas pipeline (1) leakage according to claim 4 It is characterized in that, it is characterized in that In step S4, the determination rule for the leakage of the conveying pipeline is that the low-temperature threshold within the assembly gap (12) is greater than the preset temperature reduction threshold, and the temperature within the assembly gap (12) is compared with the temperature within the assembly gaps (12) on the circumferential outer sides of two adjacent conveying pipelines through the annular temperature measuring kit (2). If the temperature difference is greater than the set temperature reduction threshold, it is determined that this section of the conveying pipeline leaks; when the conveying pipeline leaks, the positioning module (72) sends location information to the low-temperature alarm platform (5), and the pressure in the constant-pressure gap (14) increases, causing the top pressure slider (44) to slide and press the start switch (47) to trigger the sound and light alarm (49).

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