A full-length down-hole screen device for directional borehole drilling in soft coal seams

Abstract

The utility model discloses a kind of soft coal seam directional wear layer drilling whole course under screen pipe device, including inner guide rod, the inner guide rod outer wall is successively equipped with screen pipe and sheath pipe;The inner guide rod inside is equipped with the locking assembly for assisting the screen pipe and the sheath pipe location fixing;The inner guide rod is close to drilling operation end and is equipped with the advancing drilling module for assisting drilling construction, the end of the inner guide rod close to the advancing drilling module is equipped with high-pressure liquid supply equipment.Affinity effect lies in: each component in device division of labor is clear and efficient, and simplifies construction process, improves operation efficiency;Effectively avoid the hole collapse, deformation problem that drilling appears due to soft coal seam, guarantee drilling whole course structure integrity, reduce construction risk;Ensure that drilling reaches expected depth and directional accuracy, lay reliable foundation for subsequent coal seam gas extraction, grouting reinforcement etc.

Description

Technical Field

[0001] This utility model relates to the field of underground coal mine operations, specifically to a device for laying screen pipes throughout the directional drilling process in soft coal seams. Background Technology

[0002] Underground coal mine operations refer to all kinds of work activities carried out during the mining process, including coal seam exploration, drilling, mining, ventilation, gas extraction, and safety management. The complexity and high risk of underground coal mine operations require operators and equipment to possess a high degree of safety and reliability. Especially in areas such as directional drilling, coalbed methane extraction, and gas control, underground operations are crucial for ensuring miner safety, improving resource recovery rates, and reducing accident rates.

[0003] Comparing this to Chinese patent CN 105888623A, which discloses a casing reaming and screen pipe lowering device for coal mines, the device includes a casing, an openable / closeable reaming drill bit, a screen pipe, and a suspension device. The casing has a thin wall and a large through-hole diameter. The openable / closeable reaming drill bit has an openable / closeable structure at its front end, a reaming assembly at its middle outer edge, and a connecting structure at its rear end. The screen pipe and suspension device can pass through the openable / closeable reaming drill bit, and the suspension device is connected to the front end of the screen pipe. Both the openable / closeable structure and the reaming assembly are equipped with cutting elements to realize the front-end drilling and reaming operations, respectively.

[0004] In the use of the above-mentioned screen tube lowering device, although the "thin-walled, large-hole" sleeve reserves space for the lowering of the screen tube, there is a lack of rigid connection and synchronous guiding structure between the sleeve and the screen tube. During the drilling process, the sleeve needs to be lowered separately by the drill bit, while the screen tube needs to be inserted from the inside after the drill bit has completed the enlargement of the hole. The process is cumbersome and results in low work efficiency.

[0005] In addition, although the above structure has drilling and reaming functions, it only relies on the mechanical cutting action of the cutting element and does not have a coal slag cleaning device. During the drilling and reaming process in soft coal seams, a large amount of coal slag and dust are easily accumulated between the drill bit and the hole wall. On the one hand, this increases the wear of the cutting element and reduces the drilling and reaming efficiency; on the other hand, the accumulated coal slag will squeeze the hole wall of the reamed hole, causing the hole wall of the soft coal seam to collapse secondary, thus negating the supporting effect of the casing.

[0006] Therefore, there is a need for a screen pipe installation device for directional drilling through soft coal seams that is highly efficient, safe, and has components that are difficult to recover, in order to solve the above problems. Utility Model Content

[0007] The purpose of this invention is to provide a screen pipe lowering device for directional drilling through soft coal seams throughout the entire process, so as to solve the problems of low operating efficiency, low safety performance and difficulty in component recovery in the existing technology.

[0008] The purpose of this utility model is achieved as follows:

[0009] This utility model provides a full-process screen pipe lowering device for directional cross-layer drilling in soft coal seams, including an inner guide rod, on the outer wall of which a screen pipe and a protective sleeve are sequentially sleeved, and the inner guide rod and the screen pipe, as well as the screen pipe and the protective sleeve, are all clearance fits;

[0010] The inner guide rod is equipped with a locking component for assisting in the limiting and fixing of the screen tube and the sheath tube;

[0011] The inner guide rod is equipped with a traveling drilling module for assisting drilling operations near the drilling operation end, and a high-pressure liquid supply device is installed at the end of the inner guide rod near the traveling drilling module.

[0012] As an optional solution to the technical solution of this application, the traveling drilling module includes a waterproof motor fixedly installed at the end of the inner guide rod. The output end of the waterproof motor is connected to a rotating head. The rotating head has an opening on the side facing the inner guide rod, and the opening is clearance-fitted with the inner guide rod. Multiple drill bits are fixedly installed on the outside of the rotating head, and a retractable sliding cutter is movably installed on the outside of the rotating head. The sliding cutter is located at a position away from the working front end of the rotating head.

[0013] As an optional solution to the technical solution of this application, a guide plate is fixedly provided on the inner wall of the sliding cutter head, and a hole is provided on the rotating head to slide with the guide plate. A thrust spring corresponding to the guide plate is fixedly provided in the hole, and an electromagnetic plate corresponding to the guide plate is fixedly provided on the inner guide rod. When the electromagnetic plate is energized, it forms a magnetic attraction with the guide plate.

[0014] As an optional solution to the technical solution of this application, the distance between the outer wall of the drill bit and the axis of the inner guide rod is less than the inner wall radius of the screen tube. When the sliding cutter head is extended to its longest position, the distance between it and the axis of the inner guide rod is greater than the outer wall radius of the sheath tube. When the sliding cutter head is retracted to its shortest distance, the distance between it and the axis of the inner guide rod is less than the inner wall radius of the screen tube.

[0015] As an optional solution to the technical solution of this application, the inner guide rod has an inner cavity groove, and the locking assembly includes an electric telescopic rod fixedly disposed inside the inner guide rod. The telescopic end of the electric telescopic rod extends into the inner cavity groove. Multiple insert rods are slidably installed on the side wall of the inner cavity groove. The inner end of the insert rod is rotatably connected to the telescopic end of the electric telescopic rod through a traction arm. Both the screen tube and the sheath tube have openings that cooperate with the insert rods.

[0016] As an optional solution to the technical solution of this application, a sealing ring is fixedly provided at the front end of the screen tube, and the end of the sheath tube extends toward the traveling drilling module to be in close contact with the sealing ring.

[0017] As an optional solution to the technical solution of this application, the high-pressure liquid supply device includes a delivery pipe cavity that extends through the interior of the inner guide rod. The inlet end of the delivery pipe cavity is connected to an external high-pressure liquid supply device, and the outlet end of the delivery pipe cavity is equipped with a high-pressure nozzle. The high-pressure nozzle is positioned close to the traveling drilling module.

[0018] As an optional solution to the technical solution of this application, the number of high-pressure nozzles is not less than one, and the multiple high-pressure nozzles are evenly distributed in a circle with the axis of the inner guide rod as the reference.

[0019] As an optional solution to the technical solution of this application, the high-pressure nozzle is disposed between the locking assembly and the traveling drilling module. A liquid storage tank is connected to the delivery pipe cavity, and a water distribution pipe is connected to the outside of the liquid storage tank. A guide pipe is connected to the liquid inlet end of the high-pressure nozzle. The water distribution pipe and the guide pipe are connected by a flexible hose, and the flexible hose is staggered with the pulling arm and fixed to the inner wall of the inner cavity groove by a buckle.

[0020] As an optional solution to the technical solution of this application, it also includes a microcontroller. A water pressure sensor is provided inside the liquid storage tank. The electric telescopic rod, the water pressure sensor, the waterproof motor, the electromagnetic plate, and the power supply battery are all electrically connected to the microcontroller.

[0021] Positive and beneficial effects:

[0022] The device uses a traveling drilling module to perform drilling operations, and with the help of a high-pressure liquid supply device, a large amount of high-pressure water can be flushed into the hole to wash away the coal slag and dust generated during the drilling process.

[0023] The locking assembly can lock the screen tube and the protective sleeve. The protective sleeve can protect the screen tube. The inner guide rod and the drilling module can drive the screen tube to be conveyed.

[0024] After the locking components are released from the screen tube and sheath tube, external pushing and pulling equipment can be used to assist in the export of the inner guide rod, high-pressure liquid supply equipment and traveling drilling module;

[0025] After the inner wall of the hole has stabilized, the sheath tube is then led out of the hole, thus achieving precise positioning of the screen tube inside the hole.

[0026] The components of the device have clear division of labor and work together efficiently, simplifying the construction process and improving operational efficiency. It effectively avoids borehole collapse and deformation caused by soft coal seams, ensures the structural integrity of the borehole throughout the entire process, reduces construction risks, and ensures that the borehole reaches the expected depth and directional accuracy, laying a reliable foundation for subsequent coal seam gas extraction, grouting reinforcement and other operations. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the internal structure of the present invention;

[0028] Figure 2 This is the front view of the present invention;

[0029] Figure 3 This is a schematic diagram of the traveling drilling module in this utility model;

[0030] The diagram shows: inner guide rod 1, inner cavity groove 101, screen tube 2, sealing ring 201, sheath tube 3, locking assembly 4, electric telescopic rod 401, pulling arm 402, insertion rod 403, high-pressure liquid supply equipment 5, conveying pipe cavity 501, high-pressure nozzle 502, water distribution pipe 503, guide pipe 504, traveling drilling module 6, waterproof motor 601, rotating head 602, drill bit head 603, sliding cutter head 604, thrust spring 605, and electromagnetic plate 606. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] First embodiment:

[0033] See Figures 1-3 As shown, the present invention provides a screen pipe lowering device for directional drilling through soft coal seams, comprising an inner guide rod 1, which is fitted with a screen pipe 2 and a protective sleeve 3 in sequence. In order to ensure that each component can move relatively flexibly while maintaining structural stability during operation, the inner guide rod 1 and the screen pipe 2, and the screen pipe 2 and the protective sleeve 3 are all clearance fits, which can reserve the necessary space for subsequent screen pipe positioning and adjustment.

[0034] To prevent axial displacement of the screen tube 2 and the sheath tube 3 during drilling, a locking component 4 is specially installed inside the inner guide rod 1. This component can help limit and fix the screen tube 2 and the sheath tube 3. When the device completes drilling and the screen tube needs to be lowered, the locking component 4 can fix the screen tube 2 relative to the inner guide rod 1 and the sheath tube 3 relative to the screen tube 2 through the mechanical locking structure, so as to avoid the screen tube from being misaligned under the action of coal seam pressure and ensure the accurate lowering position of the screen tube.

[0035] A traveling drilling module 6 is installed near the drilling operation end of the inner guide rod 1. The drilling module 6 can achieve efficient coal breaking drilling through power drive. At the same time, in conjunction with the guiding effect of the inner guide rod 1, it ensures that the drilling direction meets the requirements of directional layer penetration and reduces the risk of drilling deviation. In addition, to further improve drilling efficiency and reduce the probability of coal seam collapse, a high-pressure liquid supply device 5 is also installed at the end of the inner guide rod 1 near the traveling drilling module 6. This device can continuously deliver high-pressure liquid, such as wall protection liquid, during the drilling process. The high-pressure liquid forms a wall protection layer on the borehole wall, which can also help enhance the drilling stability. With the impact of the high-pressure liquid, the coal slag and dust generated during the drilling process can be washed away, so that the mud can be discharged through the outer wall of the casing pipe 3.

[0036] In a preferred embodiment, an outer pipe is provided on the outside of the sheath tube 3. Cement can be used to fill the space between the outer pipe and the hole wall to solidify the hole. After the sheath tube 3 is removed, the hole can maintain a stable state for a long time, and at the same time, it provides a guarantee for the long-term reliable positioning of the screen tube 2 after the sheath tube 3 is removed.

[0037] The second embodiment differs from the first embodiment in that:

[0038] The traveling drilling module 6 includes a waterproof motor 601, which is fixedly connected to the end of the inner guide rod 1. This fixing method ensures the stability of power transmission. The output end of the waterproof motor 601 is connected to a rotating head 602. The rotational power of the waterproof motor 601 is transmitted to the rotating head 602 through a transmission structure, enabling it to rotate at high speed to break coal. To adapt to the structure of the inner guide rod 1 and reduce frictional resistance during rotation, the rotating head 602 has an opening on one side facing the inner guide rod 1. This opening is clearance-fitted with the inner guide rod 1, which provides a guiding function for the rotation of the rotating head 602 and prevents deviation during drilling.

[0039] On the outside of the rotary head 602, there are two complementary drilling components: one is a number of drill heads 603 that are fixedly installed. These drill heads serve as the basic drilling structure and can directly cut and drill into the coal seam when the rotary head 602 rotates at high speed. The drill heads 603 are used to break up the coal seam in front of the device. The other is a retractable sliding cutter head 604 that is movably installed. Unlike the drill heads 603, this cutter head is not fixed to the outside of the rotary head 602, but can be extended and retracted according to the operation requirements. Its installation position is deliberately set in an area far away from the working front end of the rotary head 602, that is, on the outside of the rotary head 602. This avoids mutual interference between the sliding cutter head 604 and the front drill head 603 during operation. It can perform secondary trimming of the hole wall or enlarge the hole diameter during the drilling process, thereby improving the drilling quality.

[0040] The structure that enables the extension and retraction of the sliding cutter head 604 mainly includes a guide plate located at the inner end of the sliding cutter head 604. This guide plate acts as a sliding guide component and forms a sliding fit with the hole opened on the rotating head 602. That is, the guide plate can slide back and forth along the inner wall of the hole, thereby driving the sliding cutter head 604 to extend and retract. To provide power for the extension of the sliding cutter head 604, a thrust spring 605 corresponding to the guide plate is fixedly installed inside the hole. When there is no external force constraint, the thrust spring 605 can generate thrust through its own elastic deformation. The guide plate is pushed, causing the sliding cutter head 604 to extend outward. The retraction of the sliding cutter head 604 is controlled by electromagnetic attraction. An electromagnetic plate 606 corresponding to the guide plate is fixed on the inner guide rod 1. The guide plate is made of iron. When the electromagnetic plate 606 is energized, it generates a magnetic attraction force. This attraction force can overcome the elastic force of the thrust spring 605 and pull the guide plate into the hole, ultimately realizing the retraction of the sliding cutter head 604. Through this combination of "spring thrust + electromagnetic attraction", the extension and retraction state of the sliding cutter head 604 can be precisely controlled.

[0041] Since the inner guide rod 1 needs to be removed later, the dimensions of the drill head 603 and the sliding head 604 need to meet the requirement of "not hindering the removal of the inner guide rod 1": specifically, the distance between the outer wall of the drill head 603 and the axis of the inner guide rod 1 is less than the inner wall radius of the screen tube 2. This means that the drill head 603 can move forward or backward through the inside of the screen tube 2, so that the traveling drilling module 6 can be pulled out after the device has completed the position of the screen tube 2; for the sliding head 604, a differentiated size structure is adopted, that is... When it extends to its longest position, the distance between it and the axis of the inner guide rod 1 is greater than the outer wall radius of the sheath tube 3, which can meet the needs of enlarging the hole diameter or trimming the hole wall. When it retracts to its shortest distance, the distance between it and the axis of the inner guide rod 1 is less than the inner wall radius of the screen tube 2, which is consistent with the size logic of the drill bit 603. This ensures that the sliding cutter head 604 will not obstruct the subsequent removal of the inner guide rod 1 from the inside of the screen tube 2 when it is retracted, thus achieving functional compatibility between "drilling operation" and "subsequent removal".

[0042] The third embodiment differs from the first embodiment in that:

[0043] The inner guide rod 1 has an inner cavity groove 101 inside. The inner cavity groove 101 is located inside the inner guide rod 1. This groove serves as a receiving structure, adapting to the size of each component of the locking assembly 4, and also needs to reserve sufficient space for the movement of the components to ensure that the locking action can be performed smoothly. The locking assembly 4 includes an electric telescopic rod 401, which is fixedly installed inside the inner guide rod 1, and its telescopic end extends into the inner cavity groove 101. Multiple insert rods 403 are slidably installed on the side wall of the inner cavity groove 101. The screen tube 2 and the sheath tube 3 are both provided with openings for insertion and mating with the insert rods 403. The insert rods 403 are the actuators for "locking", and their outer ends can extend or retract into the side wall of the inner cavity groove 101. In order for the telescopic force of the electric telescopic rod 401 to be transmitted to the insert rods 403, the inner end of the insert rod 403 and the telescopic end of the electric telescopic rod 401 are rotatably connected by a pull arm 402.

[0044] When the electric telescopic rod 401 extends, it pushes the insertion rod 403 outward along the side wall of the inner cavity groove 101 through the pulling arm 402 until the outer end of the insertion rod 403 is inserted into the corresponding opening on the screen tube 2 and the protective sleeve tube 3, fixing the screen tube 2, the protective sleeve tube 3 and the inner guide rod 1 relative to each other; when the electric telescopic rod 401 retracts, it pulls the insertion rod 403 inward through the pulling arm 402, causing it to disengage from the opening and release the lock.

[0045] In addition to the limiting and fixing structure, there is also a sealing fit structure between the screen tube 2 and the protective sleeve tube 3 to improve the sealing protection of the screen tube 2: a sealing ring 201 is fixed at the front end of the screen tube 2. The sealing ring 201 is usually made of elastic material and has a certain sealing and buffering capacity. The end of the protective sleeve tube 3 facing the traveling drilling module 6 is specially extended to a position that is in close contact with the sealing ring 201. The sealing ring 201 can fill the gap between the protective sleeve tube 3 and the screen tube 2 to prevent coal seam debris, water or other impurities from entering between the two tubes during the drilling process, and avoid impurities affecting the relative movement of the tubes or causing wear on the components.

[0046] The high-pressure liquid supply device 5 includes a delivery pipe 501 that runs through the inner guide rod 1. The inlet end of the delivery pipe 501 is connected to an external high-pressure liquid supply device, and the outlet end of the delivery pipe 501 is equipped with a high-pressure nozzle 502. The high-pressure nozzle 502 is located near the traveling drilling module 6.

[0047] The high-pressure liquid supply device 5 includes a delivery pipe 501 that runs through the inner guide rod 1. The two ends of the delivery pipe 501 are responsible for the functions of "liquid inlet" and "liquid outlet": the liquid inlet end is directly connected to the external high-pressure liquid supply device and can continuously receive high-pressure liquids, such as cooling wall protection liquids, from the outside, providing a stable liquid source for the entire liquid supply system; the liquid outlet end is equipped with a high-pressure nozzle 502, which serves as the final liquid spraying component. The high-pressure nozzle 502 can convert the high-pressure liquid transmitted by the delivery pipe 501 into a high-pressure jet, realizing the directional spraying of the liquid.

[0048] Meanwhile, to ensure that the liquid jet can directly act on the drilling operation area, the high-pressure nozzle 502 is specially positioned close to the traveling drilling module 6. On the one hand, the jetted liquid can quickly cover the drilling components such as the drill bit 603 and the sliding cutter head 604, and play a timely role in cooling, lubrication and wall protection. On the other hand, the high-pressure liquid mixes with the slag and dust generated during the drilling process to form mud. With the high pressure at the working front end, the mud can be quickly discharged from the outer wall of the casing 3 to clean the borehole.

[0049] In addition, the number of high-pressure nozzles 502 is not less than one, and can be flexibly increased or decreased according to actual operational needs such as borehole diameter and liquid demand. Secondly, when multiple high-pressure nozzles 502 are used, all nozzles are evenly distributed in a circle with the axis of the inner guide rod 1 as the reference. This distribution method allows the liquid jets sprayed by each nozzle to form a ring-shaped coverage area in the borehole, which not only avoids the occurrence of spray blind spots and ensures that all positions of the drilling parts and the borehole wall are covered by liquid, but also ensures that the liquid is evenly distributed in the borehole, preventing problems such as insufficient cooling or poor wall protection effect in local areas due to insufficient liquid, and further improving the stability and effectiveness of the liquid supply operation.

[0050] The high-pressure nozzle 502 in the high-pressure liquid supply device 5 is positioned between the locking assembly 4 and the traveling drilling module 6. This position ensures that the nozzle is close to the drilling area and avoids the moving parts of the locking assembly 4 to prevent collisions with the nozzle during component movement, which could affect the spraying effect. Specifically, a liquid storage tank is connected to the delivery pipe 501 along the liquid delivery path. This tank serves as a temporary liquid storage and pressure stabilization unit, preventing unstable spraying pressure due to fluctuations in external liquid supply pressure. A water distribution pipe 503 is connected to the outside of the liquid storage tank, acting as a liquid "diversion component" to evenly distribute the high-pressure liquid in the liquid storage tank to each high-pressure nozzle 502. The inlet end of the high-pressure nozzle 502 is connected to... There is a guide pipe 504, which serves as the "end-point delivery component" for liquids. It is responsible for accurately delivering the liquid distributed by the water distribution pipe 503 to the inside of the nozzle. In addition, the water distribution pipe 503 and the guide pipe 504 are connected by a flexible hose. The flexibility of the hose can adapt to the complex spatial environment inside the inner cavity 101 and facilitate the adjustment of the connection path according to the component layout. At the same time, in order to prevent the hose and the pulling arm 402 of the locking component 4 from getting tangled or interfering with each other during movement, the hose and the pulling arm 402 are staggered. The hose is fixed to the inner wall of the inner cavity 101 by a buckle, ensuring that the hose position is stable and does not shift with the movement of other components, thus ensuring the smoothness of liquid delivery.

[0051] The fourth embodiment differs from the first embodiment in that:

[0052] To achieve automated and coordinated operation of various functional modules, the device also includes a microcontroller. The microcontroller is used to coordinate the operation of multiple electronic control components. A water pressure sensor is installed inside the liquid storage tank. The water pressure sensor is the "monitoring sentinel" of the entire liquid supply system. Its function is to detect the liquid pressure value in the liquid storage tank in real time. When the external liquid supply pressure fluctuates or the liquid volume in the liquid storage tank changes, the water pressure sensor can quickly capture the pressure change signal and convert the signal into an electrical signal and transmit it to the microcontroller. This provides the microcontroller with data to judge the status of the liquid supply system and adjust the liquid supply parameters.

[0053] In the device, the electric telescopic rod 401, water pressure sensor, waterproof motor 601, electromagnetic plate 606, and power supply battery are all electrically connected to the microcontroller.

[0054] The operation and control of the electric telescopic rod 401, water pressure sensor, waterproof motor 601, and electromagnetic plate 606 are achieved through a microcontroller. Controlling the operation of the electric telescopic rod 401 controls the locking or unlocking of the screen tube 2 or the protective sleeve tube 3. Controlling the speed and start / stop status of the waterproof motor 601 controls drilling efficiency and accuracy. The microcontroller can send speed adjustment signals or start / stop signals to the waterproof motor 601 based on actual working conditions such as drilling progress and coal seam hardness. The microcontroller and electromagnetic plate... The electromagnetic plate 606 is electrically connected, and its on / off state determines the extension and retraction of the sliding cutter head 604. When the microcontroller determines that it is necessary to enlarge the hole diameter or trim the hole wall, it will control the electromagnetic plate 606 to be de-energized. At this time, the thrust spring 605 pushes the sliding cutter head 604 to extend. When it is necessary to retract the sliding cutter head 604, such as when the inner guide rod 1 is to be removed after drilling, the microcontroller controls the electromagnetic plate 606 to be energized, and the sliding cutter head 604 is pulled back by magnetic attraction, thus realizing the flexible control of the sliding cutter head 604.

[0055] The power supply battery serves as the "energy source" for the entire electronic control system. It is electrically connected to the microcontroller and provides stable power support for all electrical components, including the microcontroller, water pressure sensor, electric telescopic rod 401, waterproof motor 601, and electromagnetic plate 606. The microcontroller can monitor the power status of the power supply battery in real time through its built-in power management module. When the power is too low, it will issue an early warning signal in time to avoid the device from stopping or the operation from being interrupted due to power failure, thus ensuring the continuity and stability of the entire device operation process.

[0056] Specifically, the microcontroller can be either the STM32F103C8T6 industrial-grade or the MSP430F149 low-power type, which supports multiple GPIO interfaces and can meet the control requirements of the electric telescopic rod 401, waterproof motor 601, and electromagnetic plate 606. It also has an operating temperature range of -40℃ to 85℃, which is suitable for underground temperature difference environments. The latter has better low power consumption characteristics and is suitable for operation scenarios without external power supply for a long time, which can extend the battery life.

[0057] The water pressure sensor can be either the PT124G-210 diffused silicon pressure sensor or the CYB-13 strain gauge pressure sensor. The PT124G-210 has a measurement range of 0–10 MPa and an accuracy of 0.5%FS. It can monitor the high-pressure liquid pressure in the storage tank in real time, typically with a supply pressure of 2–5 MPa, and outputs a 4–20 mA analog signal, which is easily acquired by a microcontroller via an ADC module. The CYB-13 has an IP68 waterproof rating, strong shock resistance, and is suitable for downhole vibration environments. It has a measurement accuracy of 0.2%FS and is suitable for scenarios with higher pressure monitoring requirements.

[0058] The electric telescopic pole can be selected from XTL100-500, with a rated thrust of 500N and an adjustable stroke of 50-500mm, which is suitable for the telescopic distance requirements of the 403 plug pole. The output end has a built-in position feedback sensor, which can feed back the signal of the telescopic position to the microcontroller to realize closed-loop control and avoid damage to components due to excessive telescopic extension.

[0059] Waterproof motors can be selected from YBX3-90S-4 explosion-proof three-phase asynchronous motors or BLDC-60 explosion-proof brushless DC motors; they can work for a long time in dusty and humid environments, and can achieve speed regulation through electrical connection with a microcontroller via a frequency converter; BLDC brushless motors have higher speed control accuracy and low energy consumption, and are suitable for directional drilling operations that require precise drilling speed, and have built-in encoders that can feed back speed signals to the microcontroller.

[0060] Electromagnetic plate: MFZ1-3.5 series DC electromagnet with rated voltage of 24VDC and attraction force of 35N is adopted. This model of electromagnet is small in size and can be embedded in the inner wall of the inner guide rod 1. The magnetic attraction force generated after being energized can stably pull the guide plate of the sliding cutter head 604. After being de-energized, the residual magnetism is small and does not affect the thrust spring 605 to push the sliding cutter head out. The coil is made of heat-resistant enameled wire with an operating temperature of -20℃~120℃, which is suitable for the downhole temperature environment.

[0061] Each electrical device is electrically connected to the microcontroller using flame-retardant cables used in coal mines, forming a complete electrical connection network of "power supply-monitoring-control-execution". The specific path is as follows:

[0062] The power supply battery supplies power to the microcontroller, water pressure sensor, electric telescopic pole, waterproof motor, and electromagnetic plate through the main switch. The waterproof motor needs to be connected to the power supply circuit through an explosion-proof contactor. The contactor coil is electrically connected to the microcontroller, and the microcontroller controls the contactor to start and stop the motor. The electric telescopic pole, electromagnetic plate, and water pressure sensor directly convert 24V voltage to 5V or 12V through a DC / DC module to meet the low-voltage power supply requirements.

[0063] The water pressure sensor is connected to the ADC interface of the microcontroller via a shielded cable. The microcontroller converts the pressure signal into a digital signal through analog-to-digital conversion to determine in real time whether the pressure in the storage tank is within the normal range. The position feedback sensor of the electric telescopic rod and the encoder of the waterproof motor are connected to the microcontroller through GPIO and SPI interfaces, respectively, to transmit signals such as "telescopic in place" and "real-time speed" to the microcontroller as the basis for control adjustment.

[0064] The microcontroller sends control signals to the actuator through different interfaces. The electric telescopic pole outputs a PWM signal through the microcontroller's GPIO interface. After being amplified by the drive module, the PWM signal controls the electric telescopic pole motor to rotate forward and backward, thus realizing the telescopic action. At the same time, it receives position feedback sensor signals. When it detects that the "telescopic position is reached", it immediately stops outputting signals.

Claims

1. A screen pipe lowering device for directional cross-layer drilling in soft coal seams, comprising an inner guide rod (1), characterized in that: The inner guide rod (1) is fitted with a screen tube (2) and a protective sleeve (3) on its outer wall in sequence. The inner guide rod (1) and the screen tube (2), and the screen tube (2) and the protective sleeve (3) are all clearance fits. The inner guide rod (1) is provided with a locking component (4) for assisting in the limiting and fixing of the screen tube (2) and the protective sleeve (3). The inner guide rod (1) is provided with a traveling drilling module (6) for assisting drilling construction near the drilling operation end, and a high-pressure liquid supply device (5) is installed at the end of the inner guide rod (1) near the traveling drilling module (6).

2. The device for installing a screen pipe throughout the directional cross-layer drilling process in soft coal seams according to claim 1, characterized in that: The traveling drilling module (6) includes a waterproof motor (601) fixedly installed at the end of the inner guide rod (1). The output end of the waterproof motor (601) is connected to a rotating head (602). The rotating head (602) has an opening on one side facing the inner guide rod (1), and the opening is clearance-fitted with the inner guide rod (1). Multiple drill bits (603) are fixedly installed on the outside of the rotating head (602). A retractable sliding cutter head (604) is movably installed on the outside of the rotating head (602). The sliding cutter head (604) is located at a position away from the working front end of the rotating head (602).

3. The device for installing a screen pipe throughout the directional cross-layer drilling process in soft coal seams according to claim 2, characterized in that: The inner wall of the sliding cutter head (604) is fixedly provided with a guide plate. The rotating head (602) is provided with a hole that slides with the guide plate. A thrust spring (605) that corresponds to the guide plate is fixedly provided in the hole. An electromagnetic plate (606) that corresponds to the guide plate is fixedly provided on the inner guide rod (1). When the electromagnetic plate (606) is energized, it forms a magnetic attraction with the guide plate.

4. The device for installing a screen pipe throughout the directional cross-layer drilling process in soft coal seams according to claim 3, characterized in that: The distance between the outer wall of the drill bit (603) and the axis of the inner guide rod (1) is less than the inner wall radius of the screen tube (2). When the sliding cutter head (604) is extended to its longest position, the distance between it and the axis of the inner guide rod (1) is greater than the outer wall radius of the sheath tube (3). When the sliding cutter head (604) is retracted to its shortest distance, the distance between it and the axis of the inner guide rod (1) is less than the inner wall radius of the screen tube (2).

5. The device for installing a screen pipe throughout the directional cross-seam drilling process in soft coal seams according to claim 4, characterized in that: The inner guide rod (1) has an inner cavity groove (101) inside. The locking assembly (4) includes an electric telescopic rod (401) fixed inside the inner guide rod (1). The telescopic end of the electric telescopic rod (401) extends into the inner cavity groove (101). Multiple insert rods (403) are slidably installed on the side wall of the inner cavity groove (101). The inner end of the insert rod (403) is rotatably connected to the telescopic end of the electric telescopic rod (401) through a traction arm (402). The screen tube (2) and the sheath tube (3) are both provided with openings for insertion and cooperation with the insert rods (403).

6. The device for installing a screen pipe throughout the directional cross-layer drilling process in soft coal seams according to claim 5, characterized in that: The screen tube (2) is fixedly provided with a sealing ring (201) at the front end, and the sheath tube (3) extends toward the end of the traveling drilling module (6) to be in close contact with the sealing ring (201).

7. The device for installing a screen pipe throughout the directional cross-seam drilling process in soft coal seams according to claim 6, characterized in that: The high-pressure liquid supply device (5) includes a delivery tube (501) that runs through the interior of the inner guide rod (1). The inlet end of the delivery tube (501) is connected to an external high-pressure liquid supply device. The outlet end of the delivery tube (501) is equipped with a high-pressure nozzle (502). The high-pressure nozzle (502) is located close to the traveling drilling module (6).

8. The device for installing a screen pipe throughout the directional cross-seam drilling process in soft coal seams according to claim 7, characterized in that: The number of high-pressure nozzles (502) is not less than one, and the multiple high-pressure nozzles (502) are evenly distributed in a circle with the axis of the inner guide rod (1) as the reference.

9. A screen pipe lowering device for directional cross-seam drilling in soft coal seams according to claim 8, characterized in that: The high-pressure nozzle (502) is disposed between the locking assembly (4) and the traveling drilling module (6). A liquid storage tank is connected to the delivery cavity (501). A water distribution pipe (503) is connected to the outside of the liquid storage tank. A guide pipe (504) is connected to the inlet end of the high-pressure nozzle (502). The water distribution pipe (503) and the guide pipe (504) are connected by a hose. The hose and the pulling arm (402) are staggered and fixed to the inner wall of the inner cavity groove (101) by a buckle.

10. A screen pipe lowering device for directional cross-seam drilling in soft coal seams according to claim 9, characterized in that: It also includes a microcontroller. The liquid storage tank is equipped with a water pressure sensor. The electric telescopic rod (401), the water pressure sensor, the waterproof motor (601), the electromagnetic plate (606), and the power supply battery are all electrically connected to the microcontroller.

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