Wellhead gas detection system and method combining float positioning and automated multi-point sampling

Abstract

This invention provides a wellhead gas detection system and method combining float positioning and automated multi-point sampling. The system includes a storage box, a gas detector main unit located within the storage box and comprising an MCU microcontroller unit, a gas concentration sensor, and a gas pump, another gas detector main unit located within the storage box and adjacent to it, and a float body fixedly connected to the other end of a flexible hose. The flexible hose retraction device has the flexible hose main unit wrapped around its outer side, with one end of the flexible hose main unit connected to the gas pump. Within a preset detection cycle, the MCU microcontroller unit controls the flexible hose retraction device to release the flexible hose main unit carrying the float body into the well to multiple detection points. The gas pump is then activated, and the gas collected by the float body is transported through the flexible hose main unit to the gas concentration sensor for detection, with feedback sent to the MCU microcontroller unit. The solution provided by this invention enables accurate, automated, multi-point periodic gas sampling and detection within a limited operating space.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and more specifically, to a wellhead gas detection system and method that combines float positioning with automated multi-point sampling. Background Technology

[0002] In confined work environments (such as wastewater treatment plant screen wells, booster pump pits, inspection wells, combined sewer inspection wells, and box culverts), there is often a risk of harmful gases such as hydrogen sulfide, methane / flammable gases, and carbon monoxide, as well as oxygen deficiency, posing a serious threat to the lives of workers. To effectively address this challenge, the current mainstream approach is to use a pump-suction gas detector with a flexible hose to remotely sample outside the wellhead to reduce the risk of personnel exposure. However, existing technologies generally have the following problems: hose release depends on manual operation, and the sampling depth is difficult to reproduce; the end of the sampling hose is prone to accidental aspiration of liquid, leading to filter blockage and damage to the air pump / sensor due to liquid ingress, resulting in high maintenance costs; the determination of sampling points lacks a closed loop, making it impossible to reliably determine multiple sampling points using the liquid level as a reference, making it difficult to conduct multi-point testing according to established standards and specifications, thus leading to inaccurate test results. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a wellhead gas detection system and method that combines float positioning and automated multi-point sampling, so as to achieve the reproducibility of detection points at different heights in a limited space, thereby improving the reliability and accuracy of gas detection results.

[0004] To address the aforementioned technical problems, embodiments of the present invention provide a wellhead gas detection system combining float positioning and automated multi-point sampling, comprising:

[0005] Storage box;

[0006] The main unit of the gas detector is located on one side of the storage box and includes an MCU microcontroller unit, a gas concentration sensor and a gas pump. The gas concentration sensor and the gas pump are both communicatively connected to the MCU microcontroller unit.

[0007] A hose retraction device is disposed on one side inside the storage box and adjacent to the main unit of the gas detector; a hose body is wrapped around the outside of the hose retraction device, and the gas concentration sensor is disposed at one end of the hose body, and this end of the hose body is connected to the gas pump; and

[0008] The float body is fixedly connected to the other end of the hose body. Before gas detection, the float body is stored in the storage box. During gas detection, within a preset detection cycle, the MCU microcontroller unit controls the hose retraction device to start and release the hose body carrying the float body to multiple detection points above the water surface at different heights. At the same time, the MCU microcontroller unit controls the air pump to start and collect gas through the float body. The gas is then transported through the hose body to the gas concentration sensor for detection and feedback to the MCU microcontroller unit.

[0009] In one embodiment, the hose retraction device includes:

[0010] A reel, the hose body is wound around the outside of the reel, a reel encoder is integrated on the reel shaft, and a baffle is provided at one end of the reel; the reel encoder is communicatively connected to the MCU microcontroller unit, and when the hose body is retracted or extended, the reel encoder rotates synchronously with the reel and generates pulse signals during the rotation process, which are fed back to the MCU microcontroller unit;

[0011] A servo motor is located at the other end of the drum. The output shaft of the servo motor is connected to the drum shaft for transmission, and the servo motor is communicatively connected to the MCU microcontroller unit.

[0012] A guide assembly is disposed on one side of the drum and is connected to the drum drive. The guide assembly is used to guide the hose body when the servo motor is started and the drum is rotated by the MCU microcontroller unit to wind up and unwind.

[0013] In one embodiment, the guiding component includes:

[0014] A guide rail is provided on one side of the drum, and both ends of the guide rail are fixedly connected to one side of the baffle and one side of the servo motor, respectively.

[0015] A lead screw is disposed between the guide rail and the drum, and the lead screw is drively connected to the drum shaft; and

[0016] A guide seat is sleeved on the outside of the lead screw and screwed to the lead screw. One side of the guide seat is in sliding contact with the guide rail, and the top of the guide seat is in contact with the hose body.

[0017] In one embodiment, the float body includes:

[0018] A first hemisphere, wherein a gas channel is formed along its central axis, the gas channel serving as a gas sampling inlet and communicating with the main body of the flexible tube; and

[0019] The second hemisphere is disposed opposite to and fixedly connected to the first hemisphere. Both the first and second hemispheres have cavities inside, so that the first hemisphere and the air inlet can be lifted off the liquid surface through the second hemisphere.

[0020] In one embodiment, liquid level monitoring devices are spaced apart at the bottom of the second hemisphere; during the process of releasing the hose body through the hose retraction device, multiple detection points at different heights in the well are determined based on the release length of the hose body when the second hemisphere contacts the liquid surface as monitored by the liquid level monitoring devices, so as to sequentially perform gas detection on multiple detection points within a preset detection cycle.

[0021] Embodiments of the present invention also provide a detection method for a wellhead gas detection system combining float positioning and automated multi-point sampling as described in the above embodiments, comprising:

[0022] The MCU microcontroller unit initiates the hose reeling device to release the hose body into the well, and during the release process, it receives pulse signals sent by the drum encoder on the drum of the hose reeling device;

[0023] The first release length of the hose body is determined based on the pulse signal and the reel diameter;

[0024] The first release length is modified to obtain the modified first release length;

[0025] The hose body is continuously released, and during the continuous release process, the second release length of the hose body is determined based on the liquid level detection device on the float body and the preset release length threshold.

[0026] The second release length is modified to obtain the modified second release length;

[0027] Based on the corrected first release length and the corrected second release length, a third release length of the hose body is determined, wherein the corrected first release length is less than the third release length, and the third release length is less than the corrected second release length;

[0028] The well location corresponding to the corrected first release length is determined as the first detection point, the well location corresponding to the third release length is determined as the third detection point, and the well location corresponding to the corrected second release length is determined as the second detection point. Within a preset detection cycle, the hose body is sequentially controlled and released to the first detection point, the third detection point, and the second detection point, and gas sampling, detection, and recording operations are performed at the detection points.

[0029] In one embodiment, determining the second release length of the hose body during continuous release, based on the liquid level detection device on the float body and a preset release length threshold, includes:

[0030] When the current release length of the hose body is less than the preset release length threshold, if the MCU microcontroller unit continuously receives liquid surface contact detection results sent by the liquid surface detection device within a preset time period, the release of the hose body is stopped, and the second release length is determined according to the total number of pulse signals received by the MCU microcontroller unit at this moment; otherwise, the release continues until the liquid surface contact detection result is received.

[0031] When the current release length of the hose body is greater than or equal to the preset release length threshold, and the MCU microcontroller unit does not receive the liquid surface contact detection result sent by the liquid surface detection device, the second release length is determined based on the corrected first release length, the preset corrected release length, and the preset release length threshold.

[0032] In one embodiment, determining the second release length based on the modified first release length, the preset modified release length, and the preset release length threshold includes:

[0033] The second release length is determined using the following formula:

[0034] L 02 =min(L upper +ΔL def L max );

[0035] Among them, L 02 L represents the second release length; upper Indicates the corrected first release length; ΔL def L represents the preset corrected release length; max This indicates the preset release length threshold.

[0036] In one embodiment, the first release length and the second release length are corrected based on a preset drum diameter compensation table to obtain the corrected first release length and the corrected second release length; the preset drum diameter compensation table is obtained by calibrating the hose reel device based on a preset measurement length.

[0037] In one embodiment, determining the third release length of the hose body based on the modified first release length and the modified second release length includes:

[0038] The third release length is determined by the following formula:

[0039] L mid =(L upper +L lower ) / 2;

[0040] Among them, L mid L represents the third release length; lower L represents the modified second release length; upper This indicates the modified first release length.

[0041] The above-described solution of the present invention has at least the following beneficial effects:

[0042] (1) By combining the MCU microcontroller unit with the hose retraction device, the present invention can realize the automatic retraction and retraction of the hose body and the precise control of the retraction and retraction length, avoiding the errors of manual operation and providing a solid guarantee for the accuracy of wellhead gas detection; at the same time, by precisely controlling the retraction and retraction length of the hose body, gas detection points at different heights downhole can be located and gas detection at different detection points downhole can be realized, further ensuring the accuracy of gas detection.

[0043] (2) By setting the guide rail and lead screw in the guide assembly, the present invention can accurately control the guide seat to move smoothly along the drum in the hose reel device. Under the guidance of the guide seat, the hose body can be wound on the drum in an orderly and uniform manner or released along the drum axis. This effectively avoids the local accumulation of the hose body during winding or the jamming during release, ensuring the smooth and efficient operation of the hose reel and release, and providing a strong guarantee for the stable operation of the entire system.

[0044] (3) The present invention uses a double hemisphere design for the float body, which allows the first hemisphere with the air inlet to be floated on the liquid surface by the second hemisphere, thereby reducing the risk of liquid ingress during gas collection and improving the reliability and lifespan of the system; at the same time, the liquid level monitoring device set at the bottom of the second hemisphere can monitor in real time whether the float body is in contact with the liquid surface, further ensuring the accuracy of the determination of different detection points downhole, and thus ensuring the accuracy of gas detection.

[0045] (4) The detection system provided by the present invention is based on the MCU microcontroller unit, which can realize the reproducibility of different detection points and the traceability of detection result records, thereby meeting the requirements of gas detection operation permits and audit records; at the same time, it can also realize the periodic and automatic detection of gas, reduce manual dependence, and improve the efficiency and standardization of gas detection. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of the wellhead gas detection system provided in an embodiment of the present invention;

[0047] Figure 2This is a partial structural schematic diagram of a wellhead gas detection system provided in an optional embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the connection between the hose body and the float body according to an optional embodiment of the present invention;

[0049] Figure 4 This is a front view of the float body provided in an optional embodiment of the present invention;

[0050] Figure 5 This is a flowchart of a detection method based on a detection system provided in an optional embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of the calibration process for a hose reel-in / out device provided in an optional embodiment of the present invention;

[0052] Figure 7 This is a flowchart of the detection system provided in an optional embodiment of the present invention in a specific application.

[0053] The following are the reference numerals: 1. Storage box; 2. Gas detector main unit; 3. Hose retraction device; 4. Servo motor; 5. Hose body; 6. Float body; 61. First hemisphere; 62. Second hemisphere; 7. Baffle; 8. Touch screen; 9. Thermal printer; 10. Control line; 11. Guide rail; 12. Lead screw; 13. Guide seat; 14. First electrode; 15. Second electrode; 16. Connecting hose; 17. Support leg. Detailed Implementation

[0054] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0055] In the description of this invention, it should be understood that the terms "comprising / including," "consisting of," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements includes not only those elements but may also include, where necessary, other elements not expressly listed, or elements inherent to such a product, apparatus, process, or method. Without further limitation, an element defined by the phrases "comprising / including," "consisting of," does not exclude the presence of additional identical elements in the product, apparatus, process, or method that includes said element.

[0056] It should also be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of the present invention.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0058] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] like Figure 1 As shown, an embodiment of the present invention provides a wellhead gas detection system combining float positioning and automated multi-point sampling, which may include a storage box 1, a gas detector main unit 2, a hose retraction device 3, and a float body 5. The gas detector main unit 2 is located inside the storage box 1 and includes an MCU microcontroller unit, a gas concentration sensor, and a gas pump. The gas concentration sensor and the gas pump are both communicatively connected to the MCU microcontroller unit. The hose retraction device 3 is located inside the storage box and adjacent to the gas detector main unit 2; the hose body 5 is wrapped around the outside of the hose retraction device 3, and the gas concentration sensor is located at one end of the hose body 5, which is connected to the gas pump. The float body 6 is fixedly connected to the other end of the hose body 5; before gas detection, the float body 6 is stored in the storage box 1. During gas detection, within a preset detection cycle, the MCU microcontroller unit controls the hose reeling device 3 to start and release the hose body 5 carrying the float body 6 to multiple detection points above the water surface at different heights. At the same time, the MCU microcontroller unit controls the gas pump to start and collect gas through the float body 6. The gas is then transported through the hose body 5 to the gas concentration sensor for detection and feedback to the MCU microcontroller unit.

[0060] In this embodiment, before gas detection, the gas detector main unit 2, the hose retraction device 3, and the float body 5 are all stored on the same side inside the storage box 1, which facilitates carrying and transportation and ensures the safety of the components.

[0061] Based on the hose release device 3, the hose body 5 can be autonomously released and the release length can be precisely controlled. This allows for the location of detection points at different heights downhole and the detection of gas at these points. On the one hand, this improves the efficiency of gas detection, and on the other hand, it provides a more comprehensive assessment of the gas distribution at different heights within a confined space. Based on the determined detection points and the MCU microcontroller unit, the reproducibility and periodicity of gas detection at different points can be achieved, ensuring that the gas environment within the confined space is always under monitoring and guaranteeing the safety of personnel working in the confined space.

[0062] See Figure 1 In an optional embodiment of the present invention, the hose reeling device 3 may include a drum, a servo motor 4, and a guide assembly. The hose body 5 is wound around the outside of the drum, and a drum encoder is integrated on the drum shaft. The drum encoder is communicatively connected to an MCU microcontroller unit. When reeling in or unloading the hose body 5, the drum encoder rotates synchronously with the drum and generates pulse signals that are fed back to the MCU microcontroller unit during rotation.

[0063] A baffle 7 is provided at one end of the drum, and a servo motor 4 is provided at the other end of the drum. The output shaft of the servo motor 4 is connected to the drum shaft for transmission, and the servo motor 4 is connected to the MCU microcontroller unit for communication. The servo motor 4 is started by the MCU microcontroller unit, thereby realizing the automatic release of the hose body 5 and avoiding reliance on manual operation. At the same time, the baffle 7 and the servo motor 4 form limit blocks at both ends of the drum to prevent the hose body 5 from detaching from the drum.

[0064] Preferably, both the baffle 7 and the bottom of the servo motor 4 are symmetrically provided with support legs 17. One end of the support leg 17 is fixedly connected to the inner wall of the storage box 1, and the other end is fixedly connected to the bottom of the baffle 7 and the bottom of the servo motor 4 respectively, so as to support the drum in the storage box 1 and facilitate the servo motor 4 to drive the drum to rotate.

[0065] like Figure 1 and Figure 2 As shown, in an optional embodiment of the present invention, a connecting hose 16 is provided on one side of the gas detector host 2. One end of the connecting hose 16 is connected to the gas pump and the gas concentration sensor, and the other end of the connecting hose 16 is connected to one end of the hose body 5, so as to deliver the gas to the gas concentration sensor for detection.

[0066] Preferably, the gas detector host 2 is provided with a control line 10 on one side, and the other end of the control line 10 is connected to the servo motor 4 to realize the communication connection between the MCU microcontroller unit and the servo motor 4, and control the operation of the servo motor 4, so as to accurately wind or unwind the hose body 5, providing a solid guarantee for the accuracy of wellhead gas detection.

[0067] Here, the drum encoder is installed on the drum's shaft. When the servo motor 4 drives the drum to rotate, the drum encoder rotates synchronously with the drum. During rotation, the drum encoder generates pulse signals, each pulse signal corresponding to a certain rotation angle of the drum. By acquiring the pulse signals over a period of time through the MCU microcontroller unit, the total rotation angle of the drum can be calculated and obtained. Based on the total rotation angle of the drum, the release length of the hose body 5 within the corresponding time period can be calculated and obtained. Here, based on the relationship between the pulse signals generated by the drum encoder and the release length of the hose body 5, the total rotation angle of the servo motor 4 can be controlled in reverse through the MCU microcontroller unit, thereby controlling the total rotation angle of the drum. This achieves precise control of the release length or winding length of the hose body 5, accurately locating multiple detection points at different heights downhole, allowing the system to perform multi-point detection periodically, to better understand the gas distribution downhole, and thus ensure the safety of downhole operations.

[0068] A guide assembly is located on one side of the drum and connected to the drum drive. The guide assembly is used to guide the servo motor 4, which is started and drives the drum to rotate, when the servo motor 4 is controlled by the MCU microcontroller unit to unwind the hose body 5. Here, both ends of the guide assembly are connected to the shaft of the drum, and the top of the guide assembly contacts the hose body 5 to guide the hose body 5 to move along a predetermined linear track. This ensures that the winding position of the hose body 5 on the drum shifts sequentially, and that the hose body 5 is neatly arranged on the drum, with each layer of hose body 5 tightly and evenly distributed. This avoids the hose body 5 piling up in the same position on the drum during winding or jamming and damage during release. This improves the efficiency and service life of releasing or winding the hose body 5, ensuring the efficient operation of the drum and the stability of the system.

[0069] In an optional embodiment of the present invention, the guiding assembly may include a guide rail 11, a lead screw 12, and a guide seat 13. The guide rail 11 is disposed on one side of the drum, and its two ends are fixedly connected to one side of the baffle 7 and the other side of the servo motor 4, respectively. The lead screw 12 is disposed between the guide rail 11 and the drum, and is drively connected to the drum shaft. The guide seat 13 is sleeved on the outside of the lead screw 12 and screwed to it, with one side of the guide seat 13 in sliding contact with the guide rail 11, and the top of the guide seat 13 in contact with the hose body 5.

[0070] Here, the guide rail 11 is arranged in a straight line, and both the guide rail 11 and the lead screw 12 are parallel to the axis of the drum shaft. The lead screw 12 can be connected to the drum shaft by a transmission belt.

[0071] The top of the guide seat 13 has a groove that matches the outer diameter of the hose body 5 (a hose body with an outer diameter range of 4mm-8mm can be selected), and this groove slides in contact with the hose body 5. When the guide seat 13 moves, the groove limits and guides the movement of the hose body 5. Alternatively, the groove on the top of the guide seat 13 can be replaced by a circular hole through which the hose body 5 passes, and the size of the circular hole should match the outer diameter of the hose body 5. The guide seat 13 has a threaded hole that runs through the entire guide seat, and the size of this threaded hole matches the outer diameter of the lead screw 12. When the drum rotates under the drive of the servo motor 4, the drum drives the lead screw 12 to rotate synchronously. Since one side of the guide seat 13 is in sliding contact with the guide rail 11, the guide seat 13 will move evenly along the guide rail 11 under the action of abutting against the guide rail 11 and the cooperation between the threaded hole and the lead screw. At the same time, under the action of the sliding contact between the groove on its top and the hose body 5, the hose body 5 will slide along the groove, so that the hose body 5 is evenly wound or released along the drum axis under the action of the movement of the guide seat 13 and the limiting action of the groove.

[0072] It should be noted that the transmission ratio between the lead screw 12 and the drum is 1:1 to ensure synchronous rotation between the two. When winding or unwinding the hose body 5, the direction of the current of the servo motor 4 is controlled to control the forward and reverse rotation of the drum, thereby realizing the winding and unwinding of the hose body 5.

[0073] Taking the clockwise rotation of the drum to wind up the hose body 5 as an example, the specific process of cooperation between the servo motor 5, the wire assembly, and the drum is as follows: When a positive current is applied to the servo motor 4, the servo motor 4 drives the drum to rotate clockwise, and the drum synchronously drives the lead screw 12 to rotate. At this time, under the action of the threaded cooperation between the lead screw 12 and the guide seat 13, and under the action of the sliding contact between the guide rail 11 and the guide seat 13, the guide seat 13 will move along the guide rail 11. When the guide seat 13 moves, it can guide and drive the hose body 5 to wind around the drum axially through its top groove, thereby achieving winding. It should be noted that when a reverse current is applied to the servo motor 4, the servo motor 4 drives the drum to rotate counterclockwise to achieve the release of the hose body. The release process is the opposite of the winding process described above.

[0074] Here, the linear movement of the guide seat 13 along the guide rail 11 ensures that the winding position of the hose body 5 on the drum shifts successively. This shift causes the hose body 5 to form a neat arrangement on the drum, with each layer of hose body 5 being tightly and evenly distributed, and not repeatedly piled up in the same position, thereby improving the service life of the hose body 5 and ensuring the efficient operation of the drum and the stability of the system.

[0075] In an optional embodiment of the present invention, the wellhead gas detection system may further include a battery, a DC power supply, a touch screen 8, and a thermal printer 9. The battery, DC power supply, touch screen 8, and thermal printer 9 are all housed on one side of the storage box 1, as shown below. Figure 1 As shown, the touchscreen 8 is located on one side of the upper part of the gas detector main unit 2 to control its operation, and the thermal printer 9 is located on the other side of the upper part of the gas detector main unit 2 to print the gas detection results. A battery and DC power supply are used to power the system to ensure stable operation.

[0076] like Figure 3 and Figure 4 As shown, in an optional embodiment of the present invention, the float body 6 may include a first hemisphere 61 and a second hemisphere 62. The first hemisphere 61 has a gas channel along its central axis, which serves as a gas sampling inlet and communicates with the hose body. The second hemisphere 62 is opposite to and fixedly connected to the first hemisphere 61. Both the first hemisphere 61 and the second hemisphere 62 have cavities to lift the first hemisphere 61 and the inlet above the liquid surface via the second hemisphere 62, preventing accidental liquid intake during gas collection, thus significantly reducing the risk of liquid ingress into the system, improving system lifespan, and increasing detection accuracy.

[0077] Preferably, the outer diameter D of both the first hemisphere 61 and the second hemisphere 62 is in the range of 60mm-100mm; more preferably, the first hemisphere 61 and the second hemisphere 62 are spaced apart and can be fixedly connected by multiple connecting posts, and the height of the connecting posts between them should not be less than 15mm, to further avoid accidental inhalation of liquid during gas sampling.

[0078] In an optional embodiment of the present invention, liquid level monitoring devices are provided at intervals at the bottom of the second hemisphere 62; during the process of releasing the hose body 5 through the hose reeling device 3, multiple detection points with different heights in the well are determined according to the release length of the hose body 5 when the second hemisphere 62 contacts the liquid surface as monitored by the liquid level monitoring devices, so as to perform gas detection on multiple detection points sequentially within a preset detection cycle.

[0079] In this embodiment, the liquid level monitoring device monitors and provides feedback on the contact between the bottom of the second hemisphere 6 and the liquid surface in real time during the release of the hose body 5 and the float body 6. This allows for precise positioning of detection points at different heights within the well, below the wellhead and above the liquid surface, to accurately control the rotation angle of the reel and, consequently, the length of the hose body 5. This ensures the hose body 5 is precisely positioned to the corresponding detection point, and the gas at the detection point is collected and detected, guaranteeing the accuracy and rationality of the system's gas detection.

[0080] Here, the liquid level monitoring device may include a first electrode 14 and a second electrode 15 symmetrically and spaced apart at the bottom of the second hemisphere 62. The first electrode 14 and the second electrode 15 are electrically connected to the positive and negative terminals of a battery or a DC power supply via wires, and a warning light or an ammeter may be connected in series in the circuit connecting the three. During the release of the hose body 5, if the warning light illuminates or the ammeter displays a current reading, it indicates that the connection circuit between the first electrode 14, the second electrode 15 and the power supply is conductive, further indicating that the second hemisphere 62 is in contact with water. Here, the contact with water is determined by combining the electrical signals, so that the release of the hose body 5 is stopped when the second hemisphere 62 contacts water. At the same time, the rewinding length of the hose body 5 is precisely controlled to determine the detection points corresponding to different heights above the liquid surface, thereby achieving the positioning of different detection points.

[0081] It should be understood that the liquid level monitoring device is not limited to electrodes. The liquid level monitoring device can also be an ultrasonic distance sensor installed at the bottom of the second hemisphere 62. The ultrasonic distance sensor is connected to the MCU microcontroller unit to monitor the distance between the second hemisphere 62 and the liquid surface in real time during the release of the hose body 5 and feed it back to the MCU microcontroller unit, thereby realizing precise control of the retraction and extension of the hose body 5 and positioning of different detection points.

[0082] like Figure 5 As shown, embodiments of the present invention also provide a detection method for a wellhead gas detection system combining float positioning and automated multi-point sampling based on any of the above embodiments, which may include the following steps:

[0083] Step 11: The hose reel-in device 3 is started by the MCU microcontroller unit to release the hose body 5 into the well, and during the release process, the pulse signal sent by the drum encoder on the drum of the hose reel-in device 3 is received.

[0084] Step 12: Determine the first release length of the hose body 5 based on the pulse signal and the drum diameter;

[0085] Step 13: Correct the first release length to obtain the corrected first release length;

[0086] Step 14: Continuously release the hose body 5. During the continuous release process, determine the second release length of the hose body 5 based on the liquid level detection device on the float body 6 and the preset release length threshold.

[0087] Step 15: Correct the second release length to obtain the corrected second release length;

[0088] Step 16: Determine the third release length of the hose body 5 based on the corrected first release length and the corrected second release length, wherein the corrected first release length < the third release length < the corrected second release length.

[0089] Step 17: Determine the well position corresponding to the corrected first release length as the first detection point, the well position corresponding to the third release length as the third detection point, and the well position corresponding to the corrected second release length as the second detection point. Within the preset detection cycle, control and release the hose body 5 to the first detection point, the third detection point, and the second detection point in sequence, and perform gas sampling, detection, and recording operations at the detection points.

[0090] When conducting gas detection in an unknown, confined space within a well, detection points at different heights above the liquid level are first located, and the release length of the hose body 5 corresponding to each detection point is recorded. Subsequently, a fixed detection cycle is set, and within this cycle, the release length of the hose body 5 is precisely controlled to ensure it is released to the corresponding detection point. Gas collection, detection, and recording are then performed. This allows for a more comprehensive and accurate assessment of the gas environment within the confined space, ensuring personnel safety. The method described above complies with engineering testing safety regulations and improves detection efficiency and the reproducibility of detection points, providing strong support for safety audits and work permits.

[0091] Here, the servo motor 4 is first started by the MCU microcontroller unit, which drives the drum to rotate synchronously to release the hose body 5 in coordination with the guide assembly. During the release of the hose body 5, the drum encoder generates pulse signals in real time and feeds them back to the MCU microcontroller unit. Based on the received first total pulse signal and the drum diameter, the MCU microcontroller unit can calculate and obtain the preset first release length L. 01 Here, the first detection point can be the upper detection point inside the well, which can be preset by the system and adjusted according to specific detection needs.

[0092] Because gas detection in confined spaces needs to be conducted at different heights to ensure personnel safety before entry, upper detection points are set up to reduce risk and ensure that personnel are not exposed to high concentrations of harmful gases when entering the confined space. It should be understood that even if no harmful gases are detected at the upper detection point, the possibility of harmful gases being present at other heights cannot be completely ruled out. Therefore, the establishment of upper detection points ensures the comprehensiveness and standardization of gas detection, addresses dynamically changing environments, provides a basis for data recording and auditing, and reduces risk.

[0093] Since each pulse in the pulse signal corresponds to a certain rotation angle, the preset first release length L is calculated and obtained based on the total number of the first pulse signals and the drum diameter. upper The specific process is as follows:

[0094] L 01 = (N1 × π × D) / P; where N1 represents the total number of first pulse signals; D represents the drum diameter; and P represents the number of pulses generated per revolution of the drum encoder.

[0095] Here, when determining the first release length L 01 Then, based on the relationship between the total number of pulse signals and the total number of rotation angles rotated by the drum encoder (i.e., the total number of rotation angles of the drum) (θ=(N×360°) / P), the total number of rotation angles of the servo motor 4 that drives the drum and rotates the drum encoder can be determined. Furthermore, based on the initially set rotational angular velocity of the servo motor 4, the rotation time of the servo motor 4 can be obtained and controlled to precisely control the release hose body 5 to the first release length L. upper This allows for reverse control of the release or rewind length of the hose body 5. It should be noted that the rewinding process of the hose body 5 is the reverse of the release process described above.

[0096] The first release length mentioned above is calculated based on the pulse signal and the drum diameter. Since the drum diameter changes continuously during the winding and unwinding of the hose body 5 (the more turns of the hose body on the drum, the larger the drum diameter; the fewer turns of the hose body on the drum, the smaller the drum diameter), it is necessary to eliminate the influence of the drum diameter change on the calculated release length in order to ensure the accuracy of the calculation of the first release length and the second release length, thereby ensuring the accuracy of the well detection point location and further ensuring the reliability of the gas detection results.

[0097] In an optional embodiment of the present invention, step 13 above may include:

[0098] Step 131: Correct the first release length according to the preset drum diameter compensation table to obtain the corrected first release length; and the preset drum diameter compensation table is obtained by calibrating the hose reel device 3 based on the preset measurement length.

[0099] Here, the calculated first release length can be corrected based on the preset drum diameter compensation table stored in the MCU microcontroller unit, thereby obtaining the corrected first release length. Subsequently, the MCU microcontroller unit drives and controls the drum to rotate with the corrected first release length as the target, so as to release the corresponding detection point of the hose body 5 at the corresponding length.

[0100] See Figure 6The process of calibrating the hose reel device 3 based on the preset measurement length to obtain the preset drum diameter compensation table is as follows:

[0101] Step 21: Measure the calibrated release length of the hose body 5 at multiple calibration depth points (such as 1 meter, 2 meters, 5 meters, 10 meters, etc., and each depth point corresponds to the length of the released hose body 5), and simultaneously collect and record the total number of calibration pulse signals corresponding to each depth point.

[0102] Step 22: Fit the calibrated release length and the total number of calibrated pulse signals to obtain a conversion curve of "pulse number → length" and generate a preset reel diameter compensation table. This preset reel diameter compensation table records the actual release length of the hose body corresponding to different pulse numbers.

[0103] After calculating the first release length, compensation calculation (i.e., correction processing) is performed using a preset drum diameter compensation table. Specifically, based on the pulse signal of the drum encoder corresponding to the first release length, the compensation table is consulted to obtain the actual first release length of the hose body 5 corresponding to that pulse signal, and this actual first release length is determined as the corrected first release length. If the actual pulse signal is not at the precise point in the compensation table, a more accurate actual release length can be calculated using interpolation.

[0104] By using a preset drum diameter compensation table, errors in the calculated release length caused by variations in the drum diameter can be corrected, ensuring the accuracy of the calculated release length. This guarantees precise control of the hose body 5 release based on the calculated release length, thus ensuring the accuracy and reliability of gas detection results. The preset drum diameter compensation table can also be adjusted according to different well depths and hose body lengths to adapt to various detection environments. Furthermore, in practical applications, the drum diameter itself may change due to hose body wear, drum deformation, or other factors. Based on the initially calculated release length, the system can dynamically adjust initial parameters to ensure accurate measurement of the lowering length even when the initial diameter changes, thereby improving the system's flexibility and adaptability. Further compensation tables can be used to precisely compensate for the calculated release length, correcting errors caused by variations in the drum diameter (the overall diameter of the drum and its externally wound hose body), thereby improving measurement accuracy and ensuring the precision of subsequent periodic release control. The corrected first release length L is obtained. upper Then, the corrected first release length L can be... upper The corresponding location inside the well is designated as the first detection point. The hose body 5 is continuously released, and the second release length L of the hose body 5 can be determined when the liquid level detection result sent by the liquid level detection device is received or when the hose body 5 reaches the preset release length threshold. 02Here, the liquid surface contact detection result sent by the liquid surface detection device can be an electrical signal generated after the first electrode 14 and the second electrode 15 are turned on after the second hemisphere 62 in the float body 6 contacts the liquid surface, or it can be the distance between the bottom of the second hemisphere 62 and the liquid surface sent by the ultrasonic distance sensor.

[0105] Specifically, step 14 above may include:

[0106] Step 141: When the current release length of the hose body 5 is less than the preset release length threshold, if the MCU microcontroller unit continuously receives the liquid surface contact detection result sent by the liquid surface detection device within the preset time, the release of the hose body 5 is stopped, and the second release length is determined according to the total number of second pulse signals received by the MCU microcontroller unit at this moment; otherwise, the release continues until the liquid surface contact detection result is received.

[0107] When a liquid surface contact detection result is received within the preset release length threshold, it indicates that the end of the hose body 5 carrying the float body 6 has reached the deepest position in the well above the liquid surface. At this point, release of the hose body 5 is stopped, and the total number of second pulse signals received is recorded. The corresponding initial second release length is calculated and determined (the specific calculation process is the same as the calculation process of the first release length mentioned above, and will not be repeated here). After determining the initial second release length, the drive control drum is wound up the hose body 5, causing the end of the hose body 5 carrying the float body 6 to rise by an upward return distance ΔL. The second release length L is then calculated by subtracting the upward return height Δh from the initial second release length. 02 The length of the main body 5 of the winding hose is the upward return distance ΔL. By winding a certain length of the main body 5 of the hose, the type and corresponding concentration of gas above the liquid surface can be detected more accurately.

[0108] Furthermore, based on the preset drum diameter compensation table, the second release length L is calculated after calculating the difference. 02 A correction process is performed to obtain the corrected second release length L. lower and the corrected second release length L lower The corresponding release position inside the well is determined as the second detection point, and the corrected second release length L is recorded by the MCU microcontroller unit. lower and its corresponding second detection point; here, the second release length L after the difference calculation. 02 The correction process is the same as the correction process for the first release length described above, and will not be repeated here.

[0109] Here, the preset release length threshold can be set according to the total length of the hose body 5. Preferably, the preset release length threshold can be equal to the total length of the hose body 5.

[0110] Step 142: When the current release length of the hose body 5 is greater than or equal to the preset release length threshold, and the MCU microcontroller unit does not receive the liquid surface contact detection result sent by the liquid surface detection device, the second release length is determined based on the corrected first release length, the preset corrected release length, and the preset release length threshold.

[0111] When the liquid level detection equipment malfunctions or the depth above the liquid level in the well exceeds the pre-approved release length threshold, the current release length of the hose body 5 will be greater than or equal to the preset release length threshold, but no liquid level detection contact result will be received. To ensure accurate positioning of the second detection point and its corresponding second release length for gas sampling and detection at different heights, the second release length is preferably determined using the following formula:

[0112] L 02 =min(L upper +ΔL def L max );

[0113] Where, ΔL def Indicates the preset correction release length; L max This represents the preset release length threshold; it should be noted that L in the above formula... upper This is the corrected first release length; at this point, there is no need to further correct the second release length calculated under the current circumstances.

[0114] Furthermore, after determining the corrected second release length L... lower The third release length is then preferably determined using the following formula:

[0115] L mid =(L upper +L lower ) / 2;

[0116] Among them, L mid Indicates the third release length; L lower Indicates the corrected second release length; L upper This represents the corrected first release length. It should be understood that the third release length should be calculated based on the corrected first and second release lengths; therefore, further correction of the third release length is not necessary here. When determining the third release length L... mid Then, the third release length L mid The corresponding release position inside the well is the third detection point, and the third release length L is recorded by the MCU microcontroller unit. midAnd its corresponding third detection point. Here, the third detection point serves as an intermediate detection point between the first and second detection points, forming detection points at different heights (upper, middle, and lower, corresponding to the first detection point, the third detection point, and the second detection point, respectively). This enables gas sampling and detection at different heights within the well, allowing for a clearer understanding of the gas distribution within the well and ensuring the safety of operations within the well.

[0117] like Figure 7 As shown, the detection process of the detection system provided in the above embodiments in practical application will be described below through a specific embodiment:

[0118] Step 301: Set the parameters for the gas detection process and start the detection cycle:

[0119] Initial first release length L 01 The default setting is 2.0m, and its dynamic range is 0.5m–5m.

[0120] Upward return distance ΔL: Default setting is 0.30m, and its dynamic range is: 0.10m–0.50m;

[0121] Detection cycle T cycle The default setting is 15 minutes, and its dynamic range is 5 minutes to 60 minutes.

[0122] Air pump pre-charge time T purge The default setting is 10 seconds, and its dynamic range is 5 seconds to 15 seconds.

[0123] Air pump stabilization time T stable The default setting is 5 seconds, and its dynamic range is 3 seconds to 10 seconds.

[0124] Sampling time T after air pump meas The default setting is 5 seconds, and its dynamic range is 3 seconds to 10 seconds.

[0125] Preset release length threshold L max : Set according to well depth, such as 10m–30m;

[0126] Servo motor output torque: estimated based on the weight of the hose body and friction, generally greater than or equal to 0.5 N×m.

[0127] Step 302, Initialization: Complete the servo motor zero position, gas concentration sensor preheating, etc.;

[0128] Step 303, First detection point (upper point) setting: Drive the retraction device to lower to L 01 =2.0m;

[0129] Step 304, Sampling at the first detection point: Sequentially execute pump suction pre-flush time T purge Stabilization time T stable and subsequent sampling time T meas Simultaneously, the gas concentration at the first detection point is recorded;

[0130] Step 305, Water contact judgment: Continue to release the hose body 5 and detect in real time whether the first electrode 14 and the second electrode 15 are connected by electrical signals (or ultrasonic distance sensor data);

[0131] Step 306, setting the second detection point (lower point): after detecting water contact (detecting an electrical signal), immediately stop releasing the hose body and rewind the hose by a distance ΔL, and determine the extended length after rewinding as the second release length; at the same time, correct the first release length and the second release length to obtain the corrected first release length and the corrected second release length;

[0132] Step 307, Calculation of the third release length corresponding to the third detection point: according to formula L mid =(L upper +L lower ) / 2 to calculate the third release length, and determine the well location corresponding to the third release length as the third detection point;

[0133] Step 308, Sampling and testing in sequence: Pumping and sampling and testing are performed on the third detection point (middle point) according to the rhythm of step 304;

[0134] Step 309: Drive the control drum to rotate and release the hose body to the second detection point (lower point), and perform pumping sampling and detection according to the rhythm of step 304;

[0135] Step 310, Reset and Output: Retract the hose to the zero position, print the cycle test sheet and archive it, then wait for the next cycle.

[0136] When gas concentration is detected at the above detection points, if the gas concentration at any point exceeds the concentration threshold, the MCU microcontroller unit will trigger an audible and visual alarm and initiate the hose body recovery strategy.

[0137] The above embodiments of the present invention provide a detection system and detection method that can achieve reproducibility of different detection points and traceability of detection result records within a limited space, thereby satisfying the requirements for gas detection operation permits and audit trails; at the same time, it can also realize periodic and automatic gas detection, reduce reliance on manual labor, and improve the efficiency and standardization of gas detection.

[0138] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wellhead gas detection system combining float positioning and automated multi-point sampling, characterized in that, include: Storage box; The main unit of the gas detector is located on one side of the storage box and includes an MCU microcontroller unit, a gas concentration sensor and a gas pump. The gas concentration sensor and the gas pump are both communicatively connected to the MCU microcontroller unit. A hose retraction device is disposed on one side inside the storage box and adjacent to the main unit of the gas detector; a hose body is wrapped around the outside of the hose retraction device, and the gas concentration sensor is disposed at one end of the hose body, and this end of the hose body is connected to the gas pump; and A float body is fixedly connected to the other end of the hose body. The float body includes a first hemisphere and a second hemisphere. The first hemisphere has a gas channel along its central axis, which serves as a gas sampling inlet and communicates with the hose body. The second hemisphere is opposite to and fixedly connected to the first hemisphere. Both the first and second hemispheres have cavities to lift the first hemisphere and the inlet off the liquid surface through the second hemisphere. Before gas detection, the float body is stored in the storage box. During gas detection, within a preset detection cycle, the MCU microcontroller unit controls the hose retraction device to start and release the hose body carrying the float body to multiple detection points above the water surface at different heights. At the same time, the MCU microcontroller unit controls the air pump to start and collects gas through the float body, which is then transported through the hose body to the gas concentration sensor for detection and feedback to the MCU microcontroller unit. The process of determining multiple detection points includes: determining a first release length of the hose body based on the pulse signal sent by the hose reel device during operation and the drum diameter in the hose reel device; continuously releasing the hose body and determining a second release length of the hose body based on the liquid level detection device on the float body and a preset release length threshold; correcting the first release length and the second release length respectively to obtain a corrected first release length and a corrected second release length; determining a third release length of the hose body based on the corrected first release length and the corrected second release length, wherein the corrected first release length is less than the third release length, the third release length is less than the second release length, and the corrected first release length corresponds to a first detection point in the well, the third release length corresponds to a third detection point in the well, and the corrected second release length corresponds to a second detection point in the well.

2. The wellhead gas detection system combining float positioning and automated multi-point sampling according to claim 1, characterized in that, The hose retraction device includes: A reel, the hose body is wound around the outside of the reel, a reel encoder is integrated on the reel shaft, and a baffle is provided at one end of the reel; the reel encoder is communicatively connected to the MCU microcontroller unit, and when the hose body is retracted or extended, the reel encoder rotates synchronously with the reel and generates pulse signals during the rotation process, which are fed back to the MCU microcontroller unit; A servo motor is located at the other end of the drum. The output shaft of the servo motor is connected to the drum shaft for transmission, and the servo motor is communicatively connected to the MCU microcontroller unit. A guide assembly is disposed on one side of the drum and is connected to the drum drive. The guide assembly is used to guide the hose body when the servo motor is started and the drum is rotated by the MCU microcontroller unit to wind up and unwind.

3. The wellhead gas detection system combining float positioning and automated multi-point sampling according to claim 2, characterized in that, The guiding component includes: A guide rail is provided on one side of the drum, and both ends of the guide rail are fixedly connected to one side of the baffle and one side of the servo motor, respectively. A lead screw is disposed between the guide rail and the drum, and the lead screw is drively connected to the drum shaft; and A guide seat is sleeved on the outside of the lead screw and screwed to the lead screw. One side of the guide seat is in sliding contact with the guide rail, and the top of the guide seat is in contact with the hose body.

4. The wellhead gas detection system combining float positioning and automated multi-point sampling according to claim 1, characterized in that, The bottom of the second hemisphere is provided with liquid level monitoring devices at intervals; during the process of releasing the hose body through the hose retraction device, based on the release length of the hose body when the second hemisphere contacts the liquid surface as monitored by the liquid level monitoring devices, multiple detection points at different heights in the well are determined so as to perform gas detection on multiple detection points sequentially within a preset detection cycle.

5. A method for detecting gas at the wellhead, characterized in that, The method is implemented using the wellhead gas detection system according to any one of claims 1 to 4, and the method further includes: The MCU microcontroller unit initiates the hose reeling device to release the hose body into the well, and during the release process, it receives pulse signals sent by the drum encoder on the drum of the hose reeling device; Within a preset detection cycle, the hose body is sequentially controlled and released to the first detection point, the third detection point, and the second detection point, and gas sampling, detection, and recording operations are performed at the detection points.

6. The detection method of the wellhead gas detection system combining float positioning and automated multi-point sampling according to claim 5, characterized in that, During the determination of multiple detection points, the hose body is continuously released, and a second release length of the hose body is determined based on the liquid level detection device on the float body and a preset release length threshold, including: When the current release length of the hose body is less than the preset release length threshold, if the MCU microcontroller unit continuously receives liquid surface contact detection results sent by the liquid surface detection device within a preset time period, the release of the hose body is stopped, and the second release length is determined according to the total number of pulse signals received by the MCU microcontroller unit at this moment; otherwise, the release continues until the liquid surface contact detection result is received. When the current release length of the hose body is greater than or equal to the preset release length threshold, and the MCU microcontroller unit does not receive the liquid surface contact detection result sent by the liquid surface detection device, the second release length is determined based on the corrected first release length, the preset corrected release length, and the preset release length threshold.

7. The detection method of the wellhead gas detection system combining float positioning and automated multi-point sampling according to claim 6, characterized in that, Determining the second release length based on the modified first release length, the preset modified release length, and the preset release length threshold includes: The second release length is determined using the following formula: L 02 =min(L upper +ΔL def ,L max ); Among them, L 02 L represents the second release length; upper ΔL represents the corrected first release length; def L represents the preset corrected release length; max This indicates the preset release length threshold.

8. The detection method of the wellhead gas detection system combining float positioning and automated multi-point sampling according to claim 5, characterized in that, In the process of determining multiple detection points, the first release length and the second release length are corrected based on a preset roll diameter compensation table to obtain the corrected first release length and the corrected second release length. The preset reel diameter compensation table is obtained by calibrating the hose take-up and take-down device based on a preset measurement length.

9. The detection method of the wellhead gas detection system combining float positioning and automated multi-point sampling according to claim 6, characterized in that, In the process of determining multiple detection points, the third release length of the hose body is determined based on the corrected first release length and the corrected second release length, including: The third release length is determined by the following formula: L mid =(L upper +L lower ) / 2; Among them, L mid L represents the third release length; lower L represents the modified second release length; upper This indicates the modified first release length.

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