Integrated metal conduit warehouse optical fiber passive temperature and gas synchronous detection device and detection method

Abstract

The application belongs to the technical field of detection, and provides a kind of integrated metal conduit warehouse optical fiber passive temperature gas synchronous detection device, including the metal conduit with the heat conduction performance of pipe wall, multiple air inlet holes are arranged on the pipe wall of metal conduit along the axial direction, sensing optical fiber for sensing the temperature of grain pile by heat conduction of the pipe wall of metal conduit is arranged in the inside of metal conduit, and three-way joint is detachably connected to the top of metal conduit.The application uses integrated metal conduit as the physical bearing and protection structure of sensing optical fiber, simultaneously uses the inner cavity of metal conduit as gas sampling channel, so that temperature sensing and gas sampling share the same metal conduit inserted into grain pile, without respectively arranging temperature measuring rod and gas sampling pipe, fundamentally solves the problem of independent deployment of two sets of temperature and gas systems, pipeline crisscross, low system integration in prior art.

Description

Technical Field

[0001] This invention belongs to the field of detection technology, and specifically relates to an integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device and detection method. Background Technology

[0002] During long-term grain storage, the temperature field distribution and gas component concentration changes within the grain pile are two core key indicators characterizing the safety of stored grain. Specifically, abnormal localized temperature rises in the grain pile are a precursor to mold growth and pest infestation; changes in the concentrations of gases such as carbon dioxide, oxygen, and phosphine within the grain pile accurately reflect the intensity of grain respiration and metabolism, the airtightness of the grain pile, and the effectiveness of fumigation and pest control operations. Therefore, continuous, accurate, and comprehensive online monitoring of grain pile temperature and gas parameters is a crucial technical means to achieve early detection, early warning, and early handling of potential storage hazards, reduce grain losses, and ensure grain safety. Currently, existing grain pile temperature detection technologies mainly suffer from the following problems:

[0003] (1) Traditional grain temperature monitoring generally relies on RS485 bus-type electronic temperature sensors. These sensors require continuous power supply and contain active components. They are easily corroded and interfered with in the high humidity and dusty environment of grain warehouses, and cannot withstand the routine phosphine fumigation operations in grain warehouses. This results in a generally short equipment lifespan and a significant decrease in data accuracy over time. More seriously, active electronic components pose a safety hazard of electric spark ignition in the dust explosion environment of grain warehouses, directly threatening the safety of grain warehouses. Although some solutions have attempted to introduce distributed fiber optic temperature measurement technology, existing fiber optic temperature measurement solutions usually require the sensing fiber to be buried in the wall or ground in advance during the construction of grain warehouses. The construction cycle is long, the process is complex, and it is impossible to maintain or replace it later. Another solution uses a suspension method to suspend the fiber in the grain warehouse space. The fiber is exposed in the grain pile and is easily squeezed and bent during the grain entering and leaving the warehouse and during storage and settling, resulting in a decrease in temperature measurement accuracy or even fiber breakage and failure. The reliability of the system is difficult to guarantee.

[0004] (2) Outdated gas detection methods make it difficult to achieve stratified, accurate, and online detection inside grain piles. Currently, gas detection in grain warehouses still largely relies on manual sampling and laboratory analysis or on-site sampling with portable gas detectors. This method is inefficient, labor-intensive, and cannot achieve continuous online monitoring. A few grain warehouses use pre-buried gas sampling tubes, but these tubes have a single function and can only be used for gas collection. Each tube corresponds to a fixed depth measurement point. If it is necessary to obtain the gas distribution at different depths inside the grain pile, multiple sampling tubes at different depths need to be pre-buried. This is not only complex and costly, but also the single-point sampling method cannot reflect the continuous distribution characteristics of gas concentration inside the grain pile.

[0005] (3) The temperature detection and gas detection systems operate independently, each requiring independent construction, pipeline laying, and equipment maintenance. This results in a complex network of wiring within the grain depot, extremely low system integration, and a significant increase in equipment procurement costs and construction workload, placing a heavy burden on the daily management and equipment maintenance of the grain depot. More importantly, the temperature and gas data collected by the two independent systems are not synchronized in time and do not correspond in space, lacking effective spatiotemporal correlation. The upper-level monitoring system cannot perform correlation analysis between temperature changes and gas concentration changes at the same location and time, making it difficult to achieve comprehensive grain condition assessment and intelligent early warning based on multi-parameter fusion, which greatly restricts the improvement of the intelligent management level of the grain depot.

[0006] (4) Although some integrated gas sampling probes exist on the market, these probes are essentially hollow tubular structures that only serve as gas channels. They cannot simultaneously house sensing optical fibers because: the sampling probe requires negative pressure suction during operation, and its interior is a gas flow channel. If optical fibers were installed inside, the following contradictions would arise: the optical fibers would obstruct gas flow, affecting sampling response speed and gas mixing uniformity; the airflow disturbance generated by suction would interfere with the vibration noise of the optical fibers, thus affecting the accuracy and stability of distributed optical fiber temperature measurement; and the sealing problem between the probe's inner wall and the optical fiber would be difficult to solve, causing gas to leak along the gaps in the optical fibers during suction, resulting in low sampling efficiency. Therefore, in existing technologies, gas sampling probes and temperature sensing optical fibers are always deployed separately.

[0007] In summary, existing grain warehouse temperature and gas monitoring technologies suffer from a series of technical defects, including low system integration, safety hazards, limited detection accuracy, complex construction and deployment, high operation and maintenance costs, and lack of spatiotemporal correlation of data. These technologies cannot meet the development requirements of modern smart grain warehouses for grain condition monitoring systems that are "safe, reliable, accurate, efficient, highly integrated, and intelligently linked." Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes an integrated metal conduit grain silo fiber-optic passive temperature and gas synchronous detection device and method. Utilizing the inner cavity of the metal conduit as a gas sampling channel, the temperature sensor and gas sampling share the same metal conduit inserted into the grain pile, eliminating the need for separate temperature measuring rods and gas sampling tubes. This fundamentally solves the problems of independent deployment of temperature and gas systems, crisscrossing pipelines, and low system integration in existing technologies. Simultaneously, the sensing fiber is entirely housed within the metal conduit, avoiding mechanical damage to the fiber caused by grain pile settling, compression, and silo entry / exit operations, thus improving the long-term reliability and service life of the system.

[0009] The technical solution of this invention is:

[0010] This invention proposes an integrated metal conduit grain storage fiber optic passive temperature and air synchronous detection device, including a metal conduit with thermally conductive walls, multiple air inlets spaced axially on the walls of the metal conduit, and sensing optical fibers for sensing the temperature of the grain pile through heat conduction through the walls of the metal conduit. A tee connector is detachably connected to the top of the metal conduit.

[0011] The end of the sensing fiber away from the metal conduit is connected to a distributed fiber optic temperature measurement host for emitting probe light pulses and receiving and analyzing backscattered light signals to obtain distributed temperature data along the entire length of the sensing fiber. It is set outside the grain depot and has multiple fiber optic connection ports for connecting multiple sensing fibers to the distributed fiber optic temperature measurement host.

[0012] The tee connector is connected to a valve control pipeline. The valve control unit on the valve control pipeline is controlled by an external control host. The end of the valve control pipeline away from the tee connector is connected to an air exchange box. The output end of the air exchange box is connected to a detection air pipe. The end of the detection air pipe away from the air exchange box is connected to a pump suction device.

[0013] The pumping device is located outside the grain silo. The pumping device is connected to the gas detection device through an inlet gas pipe. The gas detection device is used to analyze the composition of the gas extracted by the pumping device and then transferred to the gas detection device.

[0014] Preferably, the outer diameter of the metal conduit is 8mm to 25mm, the wall thickness is 0.5mm to 2mm, and the material is stainless steel or copper alloy.

[0015] Preferably, multiple air inlets are arranged at equal or unequal intervals along the axial direction of the metal conduit, with the distance between adjacent air inlets being 0.5m to 2m, and the diameter of each air inlet being 1mm to 5mm.

[0016] Preferably, the metal conduit has an insertion end at the bottom and at least one reinforcing rib is fixedly connected to the outer wall of the metal conduit;

[0017] The insertion end has a conical or wedge-shaped tip structure.

[0018] Preferably, the main connection port of the tee connector is connected to the top of the metal conduit via a quick-release ferrule or threaded connection, and the remaining two ports are the fiber optic outlet port and the air tube connection port, respectively, with the valve control pipeline connected to the air tube connection port.

[0019] Preferably, the optical fiber outlet port is provided with an optical fiber conduit, and a sealing body is provided inside the optical fiber outlet port. The sensing optical fiber and the optical fiber outlet port are connected in a sealed manner through the sealing body.

[0020] Preferably, the sensing optical fiber is arranged in a free and relaxed state or a slightly tensioned state inside the metal conduit, and a heat-conducting medium is fixedly connected to the outer wall between the metal conduit and the sensing optical fiber. The gas detection device includes a combination of one or more gas sensors, such as a carbon dioxide sensor, an oxygen sensor, a phosphine sensor, and an ammonia sensor.

[0021] The thermally conductive medium is thermally conductive silicone grease or thermally conductive gel, and the thermally conductive medium is distributed in a point-segment pattern between the metal conduit and the sensing optical fiber.

[0022] Preferably, the device has several sets, with each metal conduit inserted into a different position in the grain pile. Each metal conduit is equipped with a sensing optical fiber, and each sensing optical fiber is connected to a separate optical fiber connection port. The air pipe connection port of each metal conduit is connected to the gas exchange box through an independent valve-controlled pipeline. The opening and closing of each valve-controlled pipeline is controlled by an external control host, so that the pumping device is connected to the opened individual valve-controlled pipeline through the gas exchange box.

[0023] The detection method for the integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device includes the following steps:

[0024] The temperature detection step involves transmitting a detection light pulse to the sensing fiber optic cable installed inside the metal conduit via a distributed fiber optic temperature measurement host, receiving and analyzing the backscattered light signal, and calculating the temperature value at each position along the entire length of the sensing fiber optic cable based on the Raman scattering principle to obtain distributed temperature distribution data of the grain pile along the axial direction of the metal conduit.

[0025] In the gas sampling step, the external control host controls the opening of the valve control unit on the target valve control pipeline, starts the pump suction device, generates negative pressure in the inner cavity of the metal conduit, and allows the gas inside the grain pile to enter the inner cavity of the metal conduit through multiple air inlets opened on the wall of the metal conduit, and then is pumped to the gas detection device through the tee joint, the valve control pipeline, the gas exchange box and the detection gas pipe.

[0026] The gas detection step involves the gas detection device analyzing the composition of the pumped gas to obtain gas concentration data inside the grain pile.

[0027] Also includes:

[0028] In the temperature detection step, the distributed optical fiber temperature measurement host emits nanosecond-level laser pulses into the sensing optical fiber, collects the Stokes component and anti-Stokes component in the backscattered Raman light, and uses the intensity ratio of the two to calculate the temperature value at each position along the sensing optical fiber.

[0029] When the device has multiple sets, in the gas sampling step, the external control host controls the valve control units on each valve control pipeline to open and close sequentially, so that the pump suction device is connected to each metal conduit sequentially through the gas exchange box, thereby realizing time-sharing gas sampling at multiple different locations in the grain pile.

[0030] In the gas sampling step, the air inlet holes on the metal conduit that are not at the target depth are blocked by a segmented sealing sleeve, leaving only the air inlet holes at the target depth unobstructed, thereby enabling gas sampling at a specific depth within the grain pile.

[0031] In the gas detection step, the gas detection device detects the concentration value of the corresponding gas by using one or more of the following sensors: carbon dioxide sensor, oxygen sensor, phosphine sensor, and ammonia sensor.

[0032] The present invention has the following advantages and effects compared with the prior art:

[0033] (1) An integrated metal conduit is used as the physical carrier and protection structure of the sensing fiber. At the same time, the inner cavity of the metal conduit is used as the gas sampling channel, so that the temperature sensing and gas sampling share the same metal conduit inserted into the grain pile. There is no need to lay out temperature measuring rods and gas sampling tubes separately, which fundamentally solves the problems of independent deployment of temperature and gas systems, crisscrossing pipelines, and low system integration in the existing technology. At the same time, the sensing fiber is completely placed inside the metal conduit, avoiding mechanical damage to the fiber caused by grain pile settling, squeezing and entering and leaving the warehouse, and improving the reliability and service life of the system in long-term operation.

[0034] (2) A distributed fiber optic temperature measurement host is used in conjunction with a sensing fiber optic cable installed in a metal conduit. Based on the Raman scattering principle, continuous distributed temperature data along the axial direction of the metal conduit is obtained, realizing continuous monitoring of the temperature field at the full depth inside the grain pile. This overcomes the defect that traditional point sensors can only obtain discrete measurement point temperatures. At the same time, by opening multiple air inlets at intervals along the axial direction on the wall of the metal conduit and using a pumping device, gas at different depths inside the grain pile can be extracted and transported to a gas detection device for component analysis. This enables synchronous detection of temperature and gas parameters in the same physical space and at the same time dimension, allowing the upper-level monitoring system to correlate temperature changes and gas concentration changes at the same location and at the same time. This provides a reliable data foundation for multi-parameter fusion analysis and intelligent early warning of grain conditions.

[0035] (3) The deployment method of inserting the metal conduit into the grain pile is adopted. The bottom of the metal conduit is equipped with a conical or wedge-shaped tip and the outer wall is equipped with reinforcing ribs to improve the insertion stiffness and bending strength. It does not need to be pre-embedded during the construction of the grain warehouse. It can be flexibly deployed and maintained and replaced after the grain warehouse is put into use. The top of the metal conduit leads out optical fiber and gas pipe through a three-way connector. The optical fiber outlet is equipped with a sealing body to ensure airtightness. The gas pipeline is equipped with a valve control unit to realize the automatic switching of multiple conduits and time-sharing sampling. It realizes multi-point deployment throughout the warehouse, remote automatic control, low power consumption passive field detection, avoids the safety hazards of active electronic components in the dusty environment of the grain warehouse, greatly reduces the equipment procurement cost and construction workload, and meets the development needs of modern smart grain warehouses for grain condition monitoring systems that are "safe and reliable, accurate and efficient, highly integrated and intelligently linked". Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0037] Figure 2 This is a partial cross-sectional view of the present invention;

[0038] Figure 3 for Figure 1 Enlarged view of point A in the middle;

[0039] Figure 4 for Figure 2 Enlarged view at point B in the middle;

[0040] Figure 5 This is a schematic diagram of the gas exchange box of the present invention.

[0041] Reference numerals: 1. Metal conduit; 101. Air inlet; 2. T-connector; 201. Fiber optic cable outlet; 202. Air pipe connection port; 203. Sealing body; 3. Valve-controlled pipeline; 301. Exchange gas box; 302. Detection air pipe; 4. Fiber optic pipeline; 5. Sensing fiber optic cable; 501. Heat-conducting medium; 6. Distributed fiber optic temperature measurement host; 601. Fiber optic connection port; 7. Gas detection device; 701. Input air pipe; 8. Pump suction device; 9. Reinforcing rib; 10. Insertion end. Detailed Implementation

[0042] To enable those skilled in the art to better understand the present invention, the invention will now be further described in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the invention.

[0043] Example 1:

[0044] like Figures 1-5As shown, this invention provides an embodiment of an integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device, including a metal conduit 1 with thermally conductive walls. The metal conduit 1 is a rigid hollow metal conduit with an outer diameter of 8mm to 25mm, a wall thickness of 0.5mm to 2mm, and is made of stainless steel or copper alloy. The total length is 5m (which can be customized according to the actual depth of the grain silo). The metal conduit 1 is used to insert into the grain pile, and its walls have good thermal conductivity.

[0045] Multiple air inlets 101 are spaced apart along the axial direction on the wall of the metal conduit 1. The multiple air inlets 101 are arranged at equal or unequal intervals along the axial direction of the metal conduit 1. The distance between adjacent air inlets 101 is 0.5m to 2m. The diameter of each air inlet 101 is 1mm to 5mm, so that gas at different depths inside the grain pile can enter the inner cavity of the metal conduit 1 through multiple air inlets 101. In practical applications, the spacing and number of air inlets 101 can be adjusted according to the depth of the grain pile so that the air inlets 101 are distributed in different depth layers of the grain pile.

[0046] The metal conduit 1 is equipped with a sensing fiber 5 for sensing the temperature of the grain pile through heat conduction through the conduit wall. The sensing fiber 5 is a multimode fiber (50 / 125μm graded refractive index multimode fiber) and is arranged along the axial direction of the metal conduit 1 in the inner cavity of the metal conduit 1. The sensing fiber 5 is in contact with the inner wall of the metal conduit 1 to sense the temperature of the grain pile outside the metal conduit 1 through heat conduction through the conduit wall. The sensing fiber 5 is arranged in a free and relaxed state or a slightly tensioned state inside the metal conduit 1. A thermally conductive medium 501 is fixedly connected to the outer wall between the metal conduit 1 and the sensing fiber 5. The thermally conductive medium 501 is thermally conductive silicone grease or thermally conductive gel to enhance the heat conduction efficiency. The thermally conductive medium 501 is distributed in a point-segment pattern between the metal conduit 1 and the sensing fiber 5.

[0047] The top of the metal conduit 1 is detachably connected to a tee connector 2. The main connection port of the tee connector 2 is connected to the top of the metal conduit 1 via a quick-release sleeve or threaded connection. The remaining two ports are the fiber optic outlet port 201 and the air pipe connection port 202, respectively. The valve control pipeline 3 is connected to the air pipe connection port 202. The fiber optic outlet port 201 is equipped with a fiber optic conduit 4. The fiber optic outlet port 201 is equipped with a sealing body 203. The sensing fiber optic cable 5 is sealed to the fiber optic outlet port 201 through the sealing body 203 to ensure that gas does not leak from the fiber optic outlet port when the pump is working.

[0048] The end of the sensing fiber 5 away from the metal conduit 1 is connected to a distributed fiber optic temperature measuring host 6, which is used to emit detection light pulses and receive and analyze backscattered light signals to obtain distributed temperature data along the entire length of the sensing fiber 5. It is set outside the grain depot. The distributed fiber optic temperature measuring host 6 is equipped with multiple fiber optic connection ports 601 for multiple sensing fibers 5 to connect to the distributed fiber optic temperature measuring host 6.

[0049] The distributed fiber optic temperature measurement host 6 is based on the Raman scattering principle. It emits nanosecond-level laser pulses into the sensing fiber 5, collects the Stokes and anti-Stokes components in the backscattered Raman light, and calculates the temperature value at each location along the fiber using the intensity ratio of the two components. The spatial resolution of temperature measurement can reach 1m, the temperature resolution is better than 0.1℃, and the temperature measurement accuracy is ±1℃.

[0050] A valve control pipeline 3 is connected to the three-way connector 2. The valve control unit on the valve control pipeline 3 is controlled by an external control host. The end of the valve control pipeline 3 away from the three-way connector 2 is connected to the air exchange box 301. The output end of the air exchange box 301 is connected to the detection air pipe 302. The end of the detection air pipe 302 away from the air exchange box 301 is connected to the pump suction device 8.

[0051] The pumping device 8 is located outside the grain silo and is a miniature diaphragm air pump or a rotary vane vacuum pump. The pumping device 8 is connected to the gas detection device 7 via the inlet air pipe 701. The gas detection device 7 is located outside the grain silo. When the pumping device 8 is working, it generates a negative pressure in the inner cavity of the metal conduit 1, drawing the gas inside the grain pile into the inner cavity of the metal conduit 1 through each air inlet 101. The gas is then drawn into the gas exchange box 301 through the three-way connector 2 and the already opened valve control pipeline 3, and then enters the gas detection device 7 through the detection air pipe 302. The gas composition is then detected by the various sensors in the gas detection device 7. The gas detection device 7 includes a carbon dioxide sensor, an oxygen sensor, a phosphine sensor, and an ammonia sensor. In actual applications, an ammonia sensor, a methane sensor, etc., can be selected according to the needs of the grain storage process.

[0052] The metal conduit 1 has an insertion end 10 at its bottom. At least one reinforcing rib 9 is connected to the outer wall of the tube body 1 and is welded to the outer wall of the metal conduit 1 along the axial direction. The reinforcing rib 9 is a stainless steel wire or narrow steel strip with a diameter of 3mm to 5mm to enhance the overall bending stiffness of the metal conduit 1 and prevent bending deformation during insertion into the grain pile. The insertion end 10 has a conical or wedge-shaped tip structure with a cone angle of about 30° to 45°, which facilitates direct insertion into the grain pile. The other end of the metal conduit 1 is an open end located outside the grain silo.

[0053] The device comprises several sets, with each metal conduit 1 inserted into different positions within the grain pile. Each metal conduit 1 contains a sensing fiber optic cable 5, and each fiber optic cable 5 is connected to a separate fiber optic connection port 601. The air pipe connection port 202 of each metal conduit 1 is connected to an air exchange box 301 via an independent valve-controlled pipeline 3. An external control unit controls the opening and closing of each valve-controlled pipeline 3, allowing the pumping device 8 to connect to the opened individual valve-controlled pipeline 3 via the air exchange box 301. Multiple metal conduits can be arranged along the top or side wall of the grain silo. Each metal conduit 1 (intervals of 3m to 5m in a grid pattern) is equipped with a sensing fiber 5. The gas connection port 202 of the tee connector 2 of each metal conduit 1 is connected to the gas exchange box 301 through an independent valve-controlled pipeline 3. The valves on each valve-controlled pipeline 3 are switched by an external control host to realize time-sharing gas sampling at each location. All sensing fibers 5 can be connected in series or switched through an optical switch to share a distributed fiber optic temperature measurement host 6 to realize distributed synchronous temperature monitoring of the entire chamber and time-sharing gas sampling analysis at multiple locations.

[0054] The detection method for the integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device includes the following steps:

[0055] In the temperature detection step, the distributed optical fiber temperature measurement host 6 sends a detection light pulse to the sensing optical fiber 5 deployed in the metal conduit 1, receives and analyzes the backscattered light signal, calculates the temperature value at each position along the entire length of the sensing optical fiber 5 based on the Raman scattering principle, and obtains the distributed temperature distribution data of the grain pile along the axial direction of the metal conduit 1.

[0056] In the gas sampling step, the external control host controls the opening of the valve control unit on the target valve control pipeline 3, starts the pump suction device 8, generates negative pressure in the inner cavity of the metal conduit 1, and causes the gas inside the grain pile to enter the inner cavity of the metal conduit 1 through multiple air inlets 101 opened on the pipe wall of the metal conduit 1, and then is pumped to the gas detection device 7 through the three-way connector 2, valve control pipeline 3, gas exchange box 301 and detection gas pipe 302.

[0057] In the gas detection step, the gas detection device 7 analyzes the composition of the pumped gas to obtain gas concentration data inside the grain pile.

[0058] Also includes:

[0059] In the temperature detection step, the distributed optical fiber temperature measurement host 6 emits nanosecond-level laser pulses to the sensing optical fiber 5, collects the Stokes component and anti-Stokes component in the backscattered Raman light, and uses the intensity ratio of the two to calculate the temperature value at each position along the sensing optical fiber 5.

[0060] When the device has multiple sets, in the gas sampling step, the external control host controls the valve control units on each valve control pipeline 3 to open and close in sequence, so that the pump suction device 8 is connected to each metal conduit 1 in sequence through the gas exchange box 301, so as to realize time-sharing gas sampling at multiple different locations in the grain pile.

[0061] In the gas sampling step, the air inlet 101 of the non-target depth layer on the metal conduit 1 is blocked by the segmented sealing sleeve, leaving only the air inlet 101 of the target depth layer open, so as to achieve gas sampling of a specific depth layer in the grain pile.

[0062] In the gas detection step, the gas detection device 7 detects the concentration value of the corresponding gas by using one or more of the following sensors installed inside: carbon dioxide sensor, oxygen sensor, phosphine sensor, and ammonia sensor.

[0063] Working principle: When it is necessary to detect the gas composition inside the grain pile, the pump suction device 8 is activated. The negative pressure is transmitted to the metal conduit 1 through the detection gas pipe 302, the gas exchange box 301, a valve-controlled pipeline 3 with the valve already opened, and the tee connector 2. Under the drive of atmospheric pressure difference, the gas at each depth layer inside the grain pile enters the inner cavity of the metal conduit 1 through each air inlet 101. After the gas at each layer is mixed in the pipe, it is drawn out to the outside of the grain silo along the inner cavity and transmitted to the gas detection device 7 through the pump suction device 8 and the input gas pipe 701. The air inlets 101 at other depths can be blocked by segmented sealing sleeves, leaving only the air inlets 101 at the target depth layer open. Inside the gas detection device 7, each gas sensor detects the concentration values ​​of preset gases such as carbon dioxide, oxygen, and phosphine. The detection data can be transmitted to the upper monitoring system for trend analysis, threshold alarms, etc.

[0064] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. All equivalent changes and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device, characterized in that, The metal conduit (1) has a heat-conducting wall. Multiple air inlets (101) are spaced apart along the axial direction on the wall of the metal conduit (1). The metal conduit (1) is equipped with a sensing fiber (5) for sensing the temperature of the grain pile through heat conduction through the wall of the metal conduit (1). A three-way connector (2) is detachably connected to the top of the metal conduit (1). The end of the sensing fiber (5) away from the metal conduit (1) is connected to a distributed fiber optic temperature measuring host (6) for emitting detection light pulses and receiving and analyzing backscattered light signals to obtain distributed temperature data along the entire length of the sensing fiber (5). It is set outside the grain depot. The distributed fiber optic temperature measuring host (6) is equipped with multiple fiber optic connection ports (601) for connecting multiple sensing fibers (5) to the distributed fiber optic temperature measuring host (6). A valve control pipeline (3) is connected to the three-way connector (2). The valve control unit on the valve control pipeline (3) is controlled by an external control host. The end of the valve control pipeline (3) away from the three-way connector (2) is connected to an air exchange box (301). The output end of the air exchange box (301) is connected to a detection air pipe (302). The end of the detection air pipe (302) away from the air exchange box (301) is connected to a pump suction device (8). The pump suction device (8) is located outside the grain silo. The pump suction device (8) is connected to the gas detection device (7) through the gas inlet pipe (701). The gas detection device (7) is used to analyze the composition of the gas extracted by the pump suction device (8) and then transferred to the gas detection device (7).

2. The integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to claim 1, characterized in that, The outer diameter of the metal conduit (1) is 8mm to 25mm, the wall thickness is 0.5mm to 2mm, and the material is stainless steel or copper alloy.

3. The integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to claim 1, characterized in that, Multiple air inlets (101) are arranged at equal or unequal intervals along the axial direction of the metal conduit (1), with the distance between adjacent air inlets (101) being 0.5m to 2m, and the diameter of each air inlet being 1mm to 5mm.

4. The integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to claim 1, characterized in that, The metal conduit (1) has an insertion end (10) at the bottom and at least one reinforcing rib (9) is fixedly connected to the outer wall of the metal conduit (1). The insertion end (10) has a conical or wedge-shaped tip structure.

5. The integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to claim 1, characterized in that, The main connection port of the tee connector (2) is connected to the top of the metal conduit (1) via a quick-release ferrule or threaded connection. The remaining two ports are the fiber optic outlet port (201) and the tracheal connection port (202), respectively. The valve-controlled pipeline (3) is connected to the tracheal connection port (202).

6. The integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to claim 5, characterized in that, The fiber optic outlet (201) is provided with a fiber optic conduit (4), and a sealing body (203) is provided inside the fiber optic outlet (201). The sensing fiber (5) is sealed to the fiber optic outlet (201) through the sealing body (203).

7. The integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to claim 1, characterized in that, The sensing fiber (5) is arranged in a free and relaxed state or a slightly tensioned state in the metal conduit (1). A heat-conducting medium (501) is fixedly connected to the outer wall between the metal conduit (1) and the sensing fiber (5). The gas detection device (7) includes a combination of one or more gas sensors, such as a carbon dioxide sensor, an oxygen sensor, a phosphine sensor, and an ammonia sensor.

8. The integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to any one of claims 7, characterized in that, The device has several sets, with each metal conduit (1) inserted into different positions of the grain pile. Each metal conduit (1) is equipped with a sensing fiber (5), and each sensing fiber (5) is connected to a single fiber connection port (601). The air pipe connection port (202) of each metal conduit (1) is connected to the gas exchange box (301) through an independent valve control pipeline (3). The opening and closing of each valve control pipeline (3) is controlled by an external control host, so that the pump suction device (8) is connected to the opened single valve control pipeline (3) through the gas exchange box (301).

9. A detection method using the integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to any one of claims 1-8, characterized in that, Includes the following steps: In the temperature detection step, the distributed optical fiber temperature measurement host (6) sends a detection light pulse to the sensing optical fiber (5) laid in the metal conduit (1), receives and analyzes the backscattered light signal, calculates the temperature value at each position along the entire length of the sensing optical fiber (5) based on the Raman scattering principle, and obtains the distributed temperature distribution data of the grain pile along the axis of the metal conduit (1). In the gas sampling step, the external control host controls the opening of the valve control unit on the target valve control pipeline (3) and starts the pump suction device (8) to generate negative pressure in the inner cavity of the metal conduit (1), so that the gas inside the grain pile enters the inner cavity of the metal conduit (1) through multiple air inlets (101) opened on the pipe wall of the metal conduit (1), and then is pumped to the gas detection device (7) through the three-way connector (2), the valve control pipeline (3), the gas exchange box (301) and the detection gas pipe (302). In the gas detection step, the gas detection device (7) performs component analysis on the pumped gas to obtain gas concentration data inside the grain pile.

10. The detection method of the integrated metal conduit grain silo fiber optic passive temperature and gas synchronous detection device according to claim 9, characterized in that, Also includes: In the temperature detection step, the distributed optical fiber temperature measurement host (6) emits a nanosecond-level laser pulse to the sensing optical fiber (5), collects the Stokes component and anti-Stokes component in the backscattered Raman light, and uses the intensity ratio of the two to calculate the temperature value at each position along the sensing optical fiber (5). When the device has multiple sets, in the gas sampling step, the external control host controls the valve control units on each valve control pipeline (3) to open and close in sequence, so that the pump suction device (8) is connected to each metal conduit (1) in sequence through the gas exchange box (301) to realize time-sharing gas sampling at multiple different locations in the grain pile; In the gas sampling step, the air inlet (101) of the metal conduit (1) that is not at the target depth layer is blocked by the segmented sealing sleeve, while the air inlet (101) at the target depth layer is kept open, so as to achieve gas sampling at a specific depth layer in the grain pile. In the gas detection step, the gas detection device (7) detects the concentration value of the corresponding gas by using one or more of the carbon dioxide sensor, oxygen sensor, phosphine sensor and ammonia sensor installed inside it.

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