Drilling tool for medium-free continuous while-drilling pressure-maintaining closed coring of broken soft coal seam

Abstract

The invention provides a broken soft coal seam medium-free continuous while-drilling pressure-maintaining closed coring drilling tool which sequentially comprises an electric drive openable drill bit, a coring cylinder outer pipe assembly and a signal transmission drill rod from front to back in the axial direction, the electric drive openable drill bit, the coring cylinder outer pipe assembly and the signal transmission drill rod are coaxially arranged, and a hollow coring cylinder inner pipe assembly is coaxially installed in the coring cylinder outer pipe assembly. And the electrically-driven openable and closable drill bit is communicated with the signal transmission drill rod, so that the electrically-driven openable and closable drill bit is opened or closed. The coring barrel outer pipe assembly is communicated with the signal transmission drill rod, and axial limiting of the coring barrel inner pipe assembly is achieved. The coring barrel inner pipe assembly is communicated with the signal transmission drill rod, and the two axial ends of an inner cavity of the coring barrel inner pipe assembly are opened or closed. And the outer side wall of the signal transmission drill rod is integrally provided with a spirally wound drill rod fin. The drilling tool is a dry type drilling tool, and it is guaranteed that the obtained coal core sample is free of pollution; according to the drilling tool, water or air does not need to be introduced in the whole drilling process and the whole sampling process, and it is guaranteed that a taken-out coal core sample is consistent with a coal body in a drilled hole in property.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal body sampling in underground coal mines, and relates to a drilling tool, in particular to a drilling tool for continuous medium-free pressure-maintained closed coring while drilling in soft and broken coal seams. BACKGROUND

[0002] Coal pressure-maintained closed coring refers to maintaining the in-situ pressure (such as gas pressure or groundwater pressure) of a coal core during drilling in underground coal mines or on the ground surface, and ensuring that the coal core does not exchange gas or liquid with the external environment during extraction. This technology is of great significance for coal mine gas extraction, coalbed methane resource assessment, water inrush mechanism research, and disaster prevention and control.

[0003] Traditional coring techniques cannot maintain the in-situ pressure and environment of the coal core, resulting in gas escape, water loss, or destruction of the coal core structure, which affects the accuracy of the data. Therefore, pressure-maintained closed coring technology has become a key research direction for safe mining and efficient utilization of resources in coal mines.

[0004] Currently, the closed pressure-maintained coring drilling tool and construction method have the following shortcomings in actual construction:

[0005] First, the coring sample is easily contaminated. The current coring drilling tool needs to throw a ball from the borehole and pass water or air to form a pressure difference to push the actuator to move when opening and closing the coring barrel during coring, which causes the coal core to exchange gas or liquid with the external environment during extraction, making the obtained sample easily contaminated and unable to guarantee purity.

[0006] Second, it cannot coring while drilling. The current coring process is to drill to the predetermined horizon first, then pull out the drill, and then lower the coring drilling tool for coring operation, which requires two trips of drilling, is time-consuming and labor-intensive, and cannot achieve coring while drilling.

[0007] Third, the coring drilling tool structure is complex and has a high failure rate. The current coring drilling tool is mostly designed with a two-layer or three-layer pipe structure, which uses a ball thrown from the borehole and water or air to form a pressure difference to push the actuator to move, and the structure is complex, maintenance is troublesome, and the failure rate is high during use. SUMMARY

[0008] In view of the deficiencies of the prior art, the purpose of the present application is to provide a drilling tool for continuous medium-free pressure-maintained closed coring while drilling in soft and broken coal seams, which solves the technical problem that in the prior art, the quality of the sample and the complexity of the device cannot be both improved when coring while drilling.

[0009] To solve the above technical problems, the present application adopts the following technical solutions:

[0010] A kind of broken soft coal seam medium-free continuous while drilling pressure maintaining closed coring drilling tool, it includes electric drive openable and closable drill bit, coring cylinder outer tube assembly and signal transmission drill rod in order from front to back along axial direction, the inside of coring cylinder outer tube assembly is coaxially installed with the inside hollow coring cylinder inner tube assembly.

[0011] The electric drive openable and closable drill bit is connected with signal transmission drill rod by insulated wire or conductive block, to realize the opening or closure of electric drive openable and closable drill bit.

[0012] The coring cylinder outer tube assembly is connected with signal transmission drill rod by insulated wire or conductive block, to realize the axial limiting of coring cylinder inner tube assembly.

[0013] The coring cylinder inner tube assembly is connected with signal transmission drill rod by insulated wire or conductive block, to realize the opening or closure of the axial both ends of the internal cavity of coring cylinder inner tube assembly.

[0014] The outer side wall of signal transmission drill rod is also integrally coaxially provided with spiral-shaped winding drill rod fin.

[0015] The present application also has the following technical features:

[0016] Preferably, the electric drive openable and closable drill bit includes drill bit body, a central through hole passing through the axial both ends is also coaxially provided in the drill bit body, the diameter of the axial front section of the central through hole is smaller than the diameter of the axial rear section of the central through hole, and the step surface at the connection between the axial front section of the central through hole and the axial rear section of the central through hole is the first limiting surface of the outer tube front end.

[0017] The axial front end of the drill bit body is also integrally provided with a plurality of fixed cutter fins, which are uniformly arranged on the outer edge of the axial front end of the drill bit body in the circumferential direction.

[0018] The axial rear end surface of the drill bit body is also embeddedly installed with a rear handle conductive block and a rear handle insulating wrapping layer, the rear handle insulating wrapping layer isolates the rear handle conductive block from the drill bit body, and the rear handle conductive block is connected with the driving motor of the electric drive openable and closable drill bit by insulated wire.

[0019] Specifically, the center of the axial front end of the drill bit body is also axially symmetrically arranged with two rotatable cutter fins, which close the axial front end of the central through hole when closed; the axial front end of the drill bit body is also installed with cutter fin rotating shafts, one-to-one corresponding to the rotatable cutter fins, the two rotatable cutter fins are installed on the drill bit body through corresponding cutter fin rotating shafts, and the two rotatable cutter fins can also rotate 90° around corresponding cutter fin rotating shafts under the driving of the driving motor of the electric drive openable and closable drill bit.

[0020] Specifically, the core barrel outer tube assembly comprises, in sequence from front to back along the axial direction, an integrated coaxially arranged outer tube front male joint, a core barrel outer tube body and an outer tube rear female joint.

[0021] The outer tube front male joint comprises a cylindrical outer tube front male joint body, an axial front end of the outer tube front male joint body is axially limited by an outer tube front first limiting surface, the outer tube front male joint body is connected with the drill bit body through external threads, and an axially through first outer tube channel is coaxially arranged in the outer tube front male joint body.

[0022] The core barrel outer tube body comprises a cylindrical outer tube body, an axial front end of the outer tube body is limited by an axial rear end surface of the drill bit body, and a plurality of outer tube front conductive units are uniformly embedded on the axial front end surface of the outer tube body in the circumferential direction.

[0023] An axially through second outer tube channel is coaxially arranged in the outer tube body, an axial front end of the second outer tube channel is connected with an axial rear end of the first outer tube channel, a step surface of the second outer tube channel close to the axial front end is an inner tube front limiting surface, a core barrel inner tube assembly is installed in the second outer tube channel, and the maximum inner diameter of the second outer tube channel is equal to the maximum outer diameter of the core barrel inner tube assembly.

[0024] Specifically, a plurality of outer tube inner wall conductive units are embedded and installed on the inner wall of the outer tube body, an electromagnetic valve assembly and an inner tube rear end locking tongue are embedded and installed on the inner wall of the outer tube body close to the axial rear end, the electromagnetic valve assembly can drive the inner tube rear end locking tongue to extend and retract along the radial direction of the second outer tube channel, thereby limiting the axial rear end of the core barrel inner tube assembly.

[0025] The outer tube rear female joint comprises an outer tube rear female joint body, a third outer tube channel is coaxially arranged in the outer tube rear female joint body, an axial front end of the third outer tube channel is connected with an axial rear end of the second outer tube channel, and a step surface-shaped transmission rod front limiting surface is arranged in the third outer tube channel.

[0026] Specifically, a plurality of outer tube rear conductive units are embedded and uniformly arranged on the axial rear end surface of the outer tube rear female joint body in the circumferential direction, the outer tube rear conductive unit comprises an outer tube rear conductive block, the outer tube rear conductive block is isolated from the outer tube rear female joint body through an outer tube rear insulating wrapping layer, and the outer tube rear conductive block can be in contact with the signal transmission drill pipe to realize mutual communication.

[0027] The structure of the outer tube front conductive unit is the same as that of the outer tube rear conductive unit.

[0028] The outer tube inner wall conductive unit comprises outer tube inner wall conductive blocks, which are insulated from the outer tube body by an outer tube inner wall insulation wrapping layer.

[0029] The conductive blocks of the outer tube front end conductive unit, the outer tube inner wall conductive blocks, the electromagnetic valve assembly, and the outer tube rear end conductive block are connected to each other by insulated wires and are insulated from the outer tube front end male joint body, the outer tube body, and the outer tube rear end female joint body.

[0030] Specifically, the core barrel inner tube assembly sequentially comprises, from front to back along the axial direction, an inner tube front end electric control valve, a core barrel inner tube body, an inner tube rear end electric control valve, and a fishing mechanism, which are coaxially arranged and threadedly connected; the inner tube front end electric control valve has the same structure as the inner tube rear end electric control valve, and the two are arranged in axial symmetry at the two ends of the core barrel inner tube body.

[0031] The inner tube front end electric control valve comprises a front end valve body shell, which sequentially comprises a front end valve body seat and a front end valve body arranged in an integrated coaxial manner from front to back along the axial direction; the axial front end of the front end valve body seat is axially limited by an inner tube front end limiting surface, the outer diameter of the front end valve body seat is equal to the maximum inner diameter of the second outer tube passage, and a plurality of inner tube front end conductive units are embeddedly installed on the outer side wall of the front end valve body seat; the plurality of inner tube front end conductive units are uniformly arranged in the circumferential direction, each inner tube front end conductive unit comprises an inner tube front end conductive block, and the inner tube front end conductive block is insulated from the front end valve body seat by an inner tube front end insulation wrapping layer; the inner tube front end conductive block is in one-to-one correspondence with and in communication with the outer tube inner wall conductive block near the axial front end of the outer tube body.

[0032] The front end valve body further coaxially has an axially through front end valve body passage, which extends forward through the inside of the front end valve body seat and is in communication with the axial rear end of the third outer tube passage; the cavity of the front end valve body passage at the middle section of the front end valve body is a spherical cavity, a front end spherical valve core is installed in the spherical cavity, a front end valve core driving motor is installed on the front end valve body, and the front end valve core driving motor can drive the front end spherical valve core to open or close the front end valve body passage.

[0033] Specifically, the core barrel inner tube body comprises an inner tube body, an inner tube body passage is coaxially arranged in the inner tube body, the diameter of the inner tube body passage is equal to the diameter of the front end valve body passage, and the axial front end of the inner tube body passage is in communication with the axial rear end of the front end valve body passage.

[0034] The rear-end electric control valve of the inner pipe comprises a rear-end valve body channel, an axial front end of the rear-end valve body channel being communicated with an axial rear end of the inner pipe body channel; an axial rear end of a rear-end valve body seat of the rear-end electric control valve of the inner pipe is axially limited by a rear-end locking tongue of the inner pipe, and the rear-end valve body seat of the rear-end electric control valve of the inner pipe is connected with an axial front end of a fishing mechanism coaxially through internal threads; a rear-end electrically-conductive block of the inner pipe is further arranged on the rear-end valve body seat of the rear-end electric control valve of the inner pipe, and the rear-end electrically-conductive block of the inner pipe is in one-to-one correspondence with and in communication with an outer pipe inner wall electrically-conductive block near an axial rear end of the outer pipe body.

[0035] The inner pipe front-end electrically-conductive block, the front-end valve core driving motor, the inner pipe rear-end electrically-conductive block of the rear-end electric control valve of the inner pipe, and the rear-end valve core driving motor of the rear-end electric control valve of the inner pipe are connected through insulated wires and are all isolated from the front-end valve body shell, the inner pipe body, and the rear-end valve body shell of the rear-end electric control valve of the inner pipe.

[0036] Specifically, the signal transmission drill rod comprises a transmission rod male joint, a transmission rod pipe body, and a transmission rod female joint which are coaxially arranged and connected in sequence along the axial direction.

[0037] The transmission rod male joint comprises a transmission rod male joint body which is connected with the outer pipe rear-end female joint body through external threads; an axial through transmission rod male joint channel is coaxially arranged in the interior of the transmission rod male joint body, and an axial front end of the transmission rod male joint channel is communicated with the third outer pipe channel.

[0038] A transmission rod front-end electrically-conductive block is mounted on an end face of the transmission rod male joint body near an inner end of the transmission rod male joint body, the transmission rod front-end electrically-conductive block is insulated and protected by a transmission rod front-end insulation layer; the transmission rod front-end electrically-conductive block can be in contact with the outer pipe rear-end electrically-conductive block and thus be communicated.

[0039] The transmission rod pipe body comprises a transmission rod pipe body, and an axial through transmission rod pipe body channel is coaxially arranged in the interior of the transmission rod pipe body.

[0040] The transmission rod female joint comprises a transmission rod female joint body, an axial through transmission rod rear-end channel is coaxially arranged in the interior of the transmission rod female joint body, an axial front end of the transmission rod rear-end channel is communicated with an axial rear end of the transmission rod male joint channel through the transmission rod pipe body channel, and the inner diameter of the transmission rod rear-end channel, the inner diameter of the transmission rod pipe body channel, and the inner diameter of the transmission rod male joint channel are all greater than the maximum outer diameter of the coring barrel inner pipe assembly.

[0041] The axial rear end surface of the transmission rod female joint body is also embeddedly installed with a transmission rod rear end conductive block, and the transmission rod rear end conductive block is insulated and protected through a transmission rod rear end insulation wrapping layer; the transmission rod rear end conductive block is also connected in communication with the transmission rod front end conductive block through an insulated wire.

[0042] Compared with the prior art, the present application has the following technical effects:

[0043] (I) The drill tool in the present application is a dry drill tool, which ensures that the coal core sample is not contaminated; the drill tool in the present application does not need to be connected with water or air during the whole drilling process and sampling process, thereby ensuring that the coal core sample does not exchange gas or liquid with the external environment during the extraction process, and the inner tube body channel of the inner tube assembly of the coring barrel enters the inner tube body channel after being sealed at both ends, thereby ensuring that the extracted coal core sample is consistent with the properties of the coal body in the borehole.

[0044] (II) The drill tool in the present application can realize continuous sampling while drilling; the drill tool in the present application can realize drilling and sampling in one, and one less drill tool is lowered; when one coring barrel inner tube assembly is full, it is taken out, and another coring barrel inner tube assembly is lowered to realize continuous sampling while drilling and pressure-keeping closed coring operation.

[0045] (III) The drill tool in the present application responds to intelligent development; the traditional pure mechanical structure is changed to an electromechanical integrated structure, and the multi-channel signal transmission drill rod is used to issue instructions to the bottom hole assembly to perform various actions, and the action response is rapid, accurate, stable and reliable.

[0046] (IV) The drill tool in the present application can be used for ordinary gas extraction hole construction and continuous sampling while drilling, improves the adaptability of the drill tool to different strata, reduces the labor intensity, improves the construction efficiency, provides technical equipment support for coal mine underground coal sampling and coal and gas control engineering, and solves the technical problems of poor adaptability of the drill tool, hole collapse after hydraulic flushing and hole opening, difficulty in lowering the screen pipe in the open hole, and the need for two operations for hydraulic flushing and screen pipe lowering. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 It is a schematic diagram of the overall cross-sectional structure of the device of the present application.

[0048] Figure 2 It is a schematic diagram of the cross-sectional structure of the electrically driven openable and closable drill bit.

[0049] Figure 3 It is a schematic diagram of the rear view structure of the electrically driven openable and closable drill bit.

[0050] Figure 4 It is a schematic diagram of the cross-sectional structure of the coring barrel outer tube assembly.

[0051] Figure 5 is a schematic diagram of the rear view structure of the outer tube assembly of the coring barrel.

[0052] Figure 6 is a schematic diagram of the cross-sectional structure of the inner tube assembly of the coring barrel.

[0053] Figure 7 is a schematic diagram of the structure of the front-end electrically controlled valve of the inner tube.

[0054] Figure 8 is a schematic diagram of the cross-sectional structure of the front-end electrically controlled valve of the inner tube.

[0055] Figure 9 is a schematic diagram of the structure of the signal transmission drill rod.

[0056] Figure 10 is a schematic diagram of the cross-sectional structure of the signal transmission drill rod.

[0057] Figure 11 is a schematic diagram of the rear view structure of the signal transmission drill rod.

[0058] The meanings of the various reference numbers in the figures are as follows: 1 - electrically driven openable and closable drill bit, 2 - outer tube assembly of the coring barrel, 3 - inner tube assembly of the coring barrel, 4 - signal transmission drill rod.

[0059] 101 - drill bit body, 102 - central through hole, 103 - first limiting surface at the front end of the outer tube, 104 - fixed blade, 105 - rotatable blade, 106 - blade rotation shaft, 107 - rear handle conductive block, 108 - rear handle insulating wrapping layer.

[0060] 201 - male connector at the front end of the outer tube, 202 - outer tube body of the coring barrel, 203 - female connector at the rear end of the outer tube.

[0061] 301 - front-end electrically controlled valve of the inner tube, 302 - inner tube body of the coring barrel, 303 - rear-end electrically controlled valve of the inner tube, 304 - fishing mechanism.

[0062] 401 - male connector of the transmission rod, 402 - tube body of the transmission rod, 403 - female connector of the transmission rod, 404 - drill rod fin.

[0063] 20101 - body of the male connector at the front end of the outer tube, 20102 - first outer tube passage.

[0064] 20201 - body of the outer tube, 20202 - conductive unit at the front end of the outer tube, 20203 - second outer tube passage, 20204 - limiting surface at the front end of the inner tube, 20205 - conductive unit on the inner wall of the outer tube, 20206 - electromagnetic valve assembly, 20207 - locking tongue at the rear end of the inner tube.

[0065] 20301-outer tube rear end female joint body, 20302-third outer tube channel, 20303-outer tube rear end conductive unit, 20304-lead front end limiting surface.

[0066] 30101-front end valve body shell, 30102-inner tube front end conductive unit, 30103-front end valve body channel, 30104-front end ball valve core, 30105-front end valve core drive motor.

[0067] 30201-inner tube body, 30202-inner tube channel.

[0068] 40101-lead male joint body, 40102-lead male joint channel, 40103-lead front end conductive block, 40104-lead front end insulation wrapping layer.

[0069] 40201-lead tube body, 40202-lead tube body channel.

[0070] 40301-lead female joint body, 40302-lead rear end channel, 40303-lead rear end conductive block, 40304-lead rear end insulation wrapping layer.

[0071] 2020501-outer tube inner wall conductive block, 2020502-outer tube inner wall insulation wrapping layer.

[0072] 2030301-outer tube rear end conductive block, 2030302-outer tube rear end insulation wrapping layer.

[0073] 3010101-front end valve body seat, 3010102-front end valve body.

[0074] 3010201-inner tube front end conductive block, 3010202-inner tube front end insulation wrapping layer.

[0075] The specific content of the present application is further described in detail below in combination with the drawings and examples. DETAILED DESCRIPTION

[0076] It should be noted that all mechanisms, components, parts and materials in the present application, such as fishing mechanism, electromagnetic valve assembly, rear handle conductive block, inner tube rear end lock tongue, special fishing spear head, front end valve core driving motor, front end spherical valve core, drill pipe fin, rear handle insulation wrapping layer and insulation material, are all known mechanisms, components, parts and materials in the prior art, unless otherwise specified.

[0077] According to the above technical solution, the specific embodiments of the present application are given below, and it should be noted that the present application is not limited to the following specific embodiments, and any equivalent changes made on the basis of the technical solution of the present application fall within the protection scope of the present application.

[0078] Embodiment:

[0079] The present embodiment gives a kind of soft coal bed without medium continuous while drilling pressure maintaining closed coring drilling tool, as shown in Figure 1 The electrically-driven openable and closable drill bit 1, the core barrel outer tube assembly 2 and the signal transmission drill pipe 4 are coaxially arranged and hollow inside, and the core barrel outer tube assembly 2 is coaxially installed with the hollow core barrel inner tube assembly 3 inside.

[0080] The electrically-driven openable and closable drill bit 1 is connected with the signal transmission drill pipe 4 through the insulating wire or the conductive block, so as to realize the opening or closing of the electrically-driven openable and closable drill bit 1.

[0081] The core barrel outer tube assembly 2 is connected with the signal transmission drill pipe 4 through the insulating wire or the conductive block, so as to realize the axial limiting of the core barrel inner tube assembly 3.

[0082] The core barrel inner tube assembly 3 is connected with the signal transmission drill pipe 4 through the insulating wire or the conductive block, so as to realize the opening or closing of the axial both ends of the internal cavity of the core barrel inner tube assembly 3.

[0083] The outer wall of the signal transmission drill pipe 4 is also integrally coaxially provided with the spiral fin 404.

[0084] As a preferred scheme of the present embodiment, as shown in Figure 2As shown, the electrically-driven openable and closable drill bit 1 comprises a drill bit body 101, and a center through hole 102 coaxially penetrating through both axial ends of the drill bit body 101 is further formed in the drill bit body 101. The diameter of the axial front section of the center through hole 102 is smaller than the diameter of the axial rear section of the center through hole 102. The stepped surface at the connection between the axial front section of the center through hole 102 and the axial rear section of the center through hole 102 is a first limiting surface 103 at the front end of the outer tube.

[0085] The axial front end of the drill bit body 101 is further integrally provided with a plurality of fixed blades 104, which are uniformly arranged along the circumferential direction of the outer edge of the axial front end of the drill bit body 101.

[0086] As shown, Figure 3 The axial rear end surface of the drill bit body 101 is further embeddedly installed with a rear handle conductive block 107 and a rear handle insulating wrapping layer 108. The rear handle insulating wrapping layer 108 insulates the rear handle conductive block 107 from the drill bit body 101. The rear handle conductive block 107 is connected to the driving motor of the electrically-driven openable and closable drill bit 1 through an insulating wire.

[0087] In this embodiment, the number of the fixed blades 104 is 4.

[0088] As a preferred scheme of this embodiment, the center of the axial front end of the drill bit body 101 is further coaxially and symmetrically arranged with two rotatable blades 105, which close the axial front end of the center through hole 102 when closed. The axial front end of the drill bit body 101 is further installed with blade rotating shafts 106, which correspond to the rotatable blades 105 one by one. The two rotatable blades 105 are installed on the drill bit body 101 through the corresponding blade rotating shafts 106. The two rotatable blades 105 can also rotate 90° around the corresponding blade rotating shafts 106 under the driving of the driving motor of the electrically-driven openable and closable drill bit 1.

[0089] In this embodiment, the rotatable blades 105 adopt the commonly used rotatable blades known in the art. The two rotatable blades are drilled when closed.

[0090] As a preferred scheme of this embodiment, as shown, Figure 4 The core barrel outer tube assembly 2 comprises, in sequence from front to rear along the axial direction, an integrally coaxially arranged outer tube front end male connector 201, a core barrel outer tube body 202, and an outer tube rear end female connector 203.

[0091] The outer pipe front end male joint 201 comprises a cylindrical outer pipe front end male joint body 20101, the axial front end of the outer pipe front end male joint body 20101 is axially limited by the outer pipe front end first limiting surface 103, the outer pipe front end male joint body 20101 is connected with the drill bit body 101 through external threads, and the first outer pipe channel 20102 axially penetrating is coaxially arranged in the outer pipe front end male joint body 20101. The axial front end of the first outer pipe channel 20102 is in communication with the axial rear end of the central through hole 102.

[0092] The outer pipe body 202 comprises a cylindrical outer pipe body 20201, the axial front end of the outer pipe body 20201 is limited by the axial rear end surface of the drill bit body 101, and a plurality of outer pipe front end conductive units 20202 are uniformly embedded and arranged on the axial front end surface of the outer pipe body 20201 in the circumferential direction.

[0093] The second outer pipe channel 20203 axially penetrating is coaxially arranged in the outer pipe body 20201, the axial front end of the second outer pipe channel 20203 is in communication with the axial rear end of the first outer pipe channel 20102, the step surface of the second outer pipe channel 20203 close to the axial front end is the inner pipe front end limiting surface 20204, the core barrel inner pipe assembly 3 is installed in the second outer pipe channel 20203, and the maximum inner diameter of the second outer pipe channel 20203 is equal to the maximum outer diameter of the core barrel inner pipe assembly 3.

[0094] As a preferred scheme of the embodiment, a plurality of outer pipe inner wall conductive units 20205 are embedded and installed on the inner wall of the outer pipe body 20201, the electromagnetic valve assembly 20206 and the inner pipe rear end lock tongue 20207 are embedded and installed on the inner wall of the outer pipe body 20201 close to the axial rear end, the electromagnetic valve assembly 20206 can drive the inner pipe rear end lock tongue 20207 to extend and retract along the radial direction of the second outer pipe channel 20203, thereby limiting the axial rear end of the core barrel inner pipe assembly 3.

[0095] The outer pipe rear end female joint 203 comprises an outer pipe rear end female joint body 20301, the third outer pipe channel 20302 axially penetrating is coaxially arranged in the outer pipe rear end female joint body 20301, the axial front end of the third outer pipe channel 20302 is in communication with the axial rear end of the second outer pipe channel 20203, and the stepped transmission rod front end limiting surface 20304 is arranged in the third outer pipe channel 20302.

[0096] As a preferred scheme of the embodiment, as shown in FIG. 1, the outer pipe body 202 is provided with a plurality of outer pipe front end conductive units 20202, the outer pipe body 202 is provided with a plurality of outer pipe inner wall conductive units 20205, the outer pipe body 202 is provided with the electromagnetic valve assembly 20206 and the inner pipe rear end lock tongue 20207, the outer pipe rear end female joint 203 is provided with the transmission rod front end limiting surface 20304, and the transmission rod 4 is provided with the transmission rod rear end limiting surface 401. Figure 5As shown, the outer tube rear end female joint body 20301 is also embedded with outer tube rear end conductive units 20303 along the circumferential direction on the axial rear end surface, the outer tube rear end conductive units 20303 include outer tube rear end conductive blocks 2030301, which are insulated from the outer tube rear end female joint body 20301 by outer tube rear end insulation layers 2030302, and can be in contact with the signal transmission drill pipe 4 to realize mutual communication.

[0097] The outer tube front end conductive unit 20202 has the same structure as the outer tube rear end conductive unit 20303.

[0098] The outer tube inner wall conductive unit 20205 includes outer tube inner wall conductive blocks 2020501, which are insulated from the outer tube body 20201 by outer tube inner wall insulation layers 2020502.

[0099] The conductive blocks of the outer tube front end conductive unit 20202, the outer tube inner wall conductive blocks 2020501, the electromagnetic valve assembly 20206, and the outer tube rear end conductive blocks 2030301 are connected to each other by insulated wires, and are insulated from the outer tube front end male joint body 20101, the outer tube body 20201, and the outer tube rear end female joint body 20301.

[0100] As a preferred scheme of the present embodiment, as shown in Figure 6 The core barrel inner tube assembly 3 includes, in sequence from front to rear along the axial direction, an inner tube front end electric control valve 301, a core barrel inner tube body 302, an inner tube rear end electric control valve 303, and a fishing mechanism 304, which are coaxially arranged and threadedly connected; the inner tube front end electric control valve 301 has the same structure as the inner tube rear end electric control valve 303, and both are arranged in axial symmetry at the two ends of the core barrel inner tube body 302.

[0101] As shown in Figure 7 and Figure 8As shown, the electric-controlled valve 301 at the front end of the inner tube includes a front end valve body shell 30101, which includes an integrated coaxial front end valve body seat 3010101 and a front end valve body 3010102 in sequence from front to back along the axial direction; the axial front end of the front end valve body seat 3010101 is axially limited by the front end limiting surface 20204 of the inner tube, the outer diameter of the front end valve body seat 3010101 is equal to the maximum inner diameter of the second outer tube channel 20203, and the outer side wall of the front end valve body seat 3010101 is also embedded with Multiple inner tube front end conductive units 30102 are evenly arranged along the circumferential direction, and each inner tube front end conductive unit 30102 includes an inner tube front end conductive block 3010201, and the inner tube front end conductive block 3010201 is isolated from the front end valve body seat 3010101 by the inner tube front end insulating wrapping layer 3010202; the inner tube front end conductive block 3010201 also corresponds one to one with the outer tube inner wall conductive block 2020501 at the axial front end near the outer tube body 20201 and is connected to each other.

[0102] An axially penetrating front-end valve body channel 30103 is coaxially opened in the front-end valve body 3010102, and the front-end valve body channel 30103 extends axially forward through the interior of the front-end valve body seat 3010101 and is connected to the axial rear end of the third outer tube channel 20302; the cavity of the front-end valve body channel 30103 at the middle section of the front-end valve body 3010102 is a spherical cavity, and a front-end spherical valve core 30104 is also installed in the spherical cavity, and a front-end valve core drive motor 30105 is also installed on the front-end valve body 3010102, and the front-end valve core drive motor 30105 can drive the front-end spherical valve core 30104 to open or close the front-end valve body channel 30103.

[0103] As a preferred solution of this embodiment, the inner tube body 302 of the core sampling tube includes an inner tube body main body 30201, and an inner tube body channel 30202 is coaxially opened in the inner tube body main body 30201. The diameter of the inner tube body channel 30202 is equal to the diameter of the front end valve body channel 30103, and the axial front end of the inner tube body channel 30202 is connected to the axial rear end of the front end valve body channel 30103.

[0104] The inner tube rear end electrically controlled valve 303 includes a rear end valve body channel, the axial front end of the rear end valve body channel is connected to the axial rear end of the inner tube body channel 30202; the axial rear end of the rear end valve body seat of the inner tube rear end electrically controlled valve 303 can be axially limited by the inner tube rear end locking tongue 20207, and the rear end valve body seat of the inner tube rear end electrically controlled valve 303 is also connected to the axial front end of the coaxially arranged salvage mechanism 304 through an internal thread; an inner tube rear end conductive block is also provided on the rear end valve body seat of the inner tube rear end electrically controlled valve 303, and the inner tube rear end conductive block is also in one-to-one correspondence with the outer tube inner wall conductive block 2020501 near the axial rear end of the outer tube body 20201 and is connected to each other.

[0105] The front end conductive block 3010201 of the inner tube, the front end valve core drive motor 30105, the rear end conductive block of the inner tube rear end electric control valve 303 and the rear end valve core drive motor of the inner tube rear end electric control valve 303 are connected by insulated wires and are isolated from the front end valve body shell 30101, the inner tube body 30201 and the rear end valve body shell of the inner tube rear end electric control valve 303.

[0106] In this embodiment, when the front end spherical valve core 30104 is opened, the diameter of the valve core internal channel, the diameter of the front end valve body channel 30103 and the diameter of the inner tube channel 30202 are all equal.

[0107] As a preferred solution of this embodiment, Figures 9 to 11 As shown, the signal transmission drill rod 4 includes a transmission rod male connector 401, a transmission rod tube body 402 and a transmission rod female connector 403 which are coaxially arranged and connected in sequence from front to back along the axial direction;

[0108] The transfer rod male connector 401 includes a transfer rod male connector body 40101, which is connected to the female connector body 20301 at the rear end of the outer tube via an external thread. An axially extending transfer rod male connector passage 40102 is coaxially defined within the transfer rod male connector body 40101, and the axial front end of the transfer rod male connector passage 40102 is connected to the third outer tube passage 20302.

[0109] A conductive block 40103 is embedded on the end surface of the transmission rod male connector 401, near the inner end of the transmission rod male connector body 40101. The conductive block 40103 is insulated and protected by an insulating wrapping layer 40104. The conductive block 40103 is able to contact and connect with the conductive block 2030301 at the rear end of the outer tube.

[0110] The transmission rod tube body 402 includes a transmission rod tube body 40201 , and an axially penetrating transmission rod tube body channel 40202 is coaxially opened inside the transmission rod tube body 40201 ;

[0111] The transmission rod female joint 403 comprises a transmission rod female joint body 40301, and an axially through transmission rod rear end passage 40302 is further coaxially arranged in the transmission rod female joint body 40301. An axially front end of the transmission rod rear end passage 40302 is connected with an axially rear end of the transmission rod male joint passage 40102 through the transmission rod pipe body passage 40202. The inner diameter of the transmission rod rear end passage 40302, the inner diameter of the transmission rod pipe body passage 40202 and the inner diameter of the transmission rod male joint passage 40102 are all greater than the maximum outer diameter of the coring barrel inner tube assembly 3.

[0112] An axially rear end surface of the transmission rod female joint body 40301 is further embeddedly installed with a transmission rod rear end conductive block 40303, and the transmission rod rear end conductive block 40303 is insulated and protected through a transmission rod rear end insulation wrapping layer 40304. The transmission rod rear end conductive block 40303 is further connected with the transmission rod front end conductive block 40103 through an insulated wire.

[0113] In this embodiment, the insulated wires in the signal transmission drill rod 4 are all wrapped with wear-resistant protective layers. The insulated wires in the signal transmission drill rod 4 are arranged on the signal transmission drill rod 4 according to the arrangement mode of the helical winding of the drill rod fins 404, and the insulated wires arranged on the signal transmission drill rod 4 are attached to the outer lateral wall surface of the signal transmission drill rod 4.

[0114] In this embodiment, the materials of the rear insulation wrapping layer 108, the transmission rod front end insulation wrapping layer 40104, the transmission rod rear end insulation wrapping layer 40304, the outer pipe inner wall insulation wrapping layer 2020502, the outer pipe rear end insulation wrapping layer 2030302 and the inner tube front end insulation wrapping layer 3010202 are all insulating materials.

[0115] In this embodiment, the connection between the electrically driven openable and closable drill bit 1 and the coring barrel outer pipe assembly 2 is sealed, the connection between the coring barrel outer pipe assembly 2 and the signal transmission drill rod 4 is sealed, and the contact between the coring barrel outer pipe assembly 2 and the inner tube front end electric control valve 301 is also sealed.

[0116] In this embodiment, the driving motor of the electrically driven openable and closable drill bit 1, the electromagnetic valve assembly 20206, the front end valve core driving motor 30105 and the rear end valve core driving motor of the inner tube rear end electric control valve 303 are all explosion-proof electronic products meeting the use conditions of coal mine underground containing gas. The driving motor of the electrically driven openable and closable drill bit 1, the electromagnetic valve assembly 20206, the front end valve core driving motor 30105 and the rear end valve core driving motor of the inner tube rear end electric control valve 303 are all the driving motor, the electromagnetic valve assembly, the front end valve core driving motor and the rear end valve core driving motor of the inner tube rear end electric control valve of the electrically driven openable and closable drill bit commonly known in the art.

[0117] In this embodiment, the electrically driven openable and closable drill bit 1, the core barrel outer tube assembly 2 and the signal transmission drill rod 4 are connected in sequence, and then the core barrel inner tube assembly 3 is installed inside the core barrel outer tube assembly 2; then the rear guide electrically conductive block 107 is in contact with the electrically conductive block of the front end electrically conductive unit 20202 of the outer tube, the inner wall electrically conductive block 2020501 of the outer tube is in contact with the front end electrically conductive block 3010201 of the inner tube and the rear end electrically conductive block of the rear end electrically controlled valve 303 of the inner tube, the rear end electrically conductive block 2030301 of the outer tube is in contact with the front end electrically conductive block 40103 of the transmission rod, and finally the circuit is turned on.

[0118] The method for using the device in this embodiment specifically includes the following steps:

[0119] Step one, drill tool connection:

[0120] The electrically driven openable and closable drill bit 1, the core barrel outer tube assembly 2 and the signal transmission drill rod 4 are connected in sequence, and the core barrel inner tube assembly 3 is installed inside the core barrel outer tube assembly 2.

[0121] Step two, normal drilling:

[0122] The dry gas extraction hole drilling is performed, no medium such as clean water or air is introduced, the coal cinder is pushed out of the drill hole by the rotation of the drill rod fin 404 of the signal transmission drill rod 4, the two rotatable blade wings 105 of the electrically driven openable and closable drill bit 1 are in a closed state, that is, the axial front end of the central through hole 102 is completely closed to avoid impurities entering the inner tube body passage 30202, the front end spherical valve core 30104 and the rear end spherical valve core of the rear end electrically controlled valve 303 are in an open state, and full-section drilling is performed.

[0123] Step three, sealed pressure maintaining coring:

[0124] The drilling reaches the predetermined coal seam section, an action signal is sent to the electrically driven openable and closable drill bit 1 through the signal transmission drill rod 4, the two rotatable blade wings 105 are rotated by 90° to be opened, the coal body passes through the central through hole 102 of the electrically driven openable and closable drill bit 1, the axial front section of the first outer tube passage 20102 and the second outer tube passage 20203 and the front end valve body passage 30103 in sequence, and finally enters the inner tube body passage 30202; when the drilling depth is equal to the length of the inner tube body passage 30202, an action signal is sent to the front end valve core driving motor 30105 and the rear end valve core driving motor of the rear end electrically controlled valve 303 through the signal transmission drill rod 4, the front end spherical valve core 30104 at the axial both ends of the core barrel inner tube assembly 3 and the rear end spherical valve core of the rear end electrically controlled valve 303 are rotated by 90° to be closed, and the coal body is sealed in the inner tube body passage 30202 to maintain the original state.

[0125] Step four, core barrel extraction:

[0126] The dedicated spear head is hooked to the fishing mechanism 304, and after the connection is stable, a signal transmission drill pipe 4 is used to send an action signal to the electromagnetic valve assembly 20206. The rear end locking tongue 20207 of the inner tube is retracted radially to release the axial positioning of the core barrel inner tube assembly 3. At this time, the core barrel inner tube assembly 3 can be pulled out of the borehole along the third outer tube passage 20302, the transmission rod male connector passage 40102, and the transmission rod rear end passage 40302.

[0127] Step five, lower a new core barrel:

[0128] The new core barrel inner tube assembly 3 is lowered, and when the axial front end of the core barrel inner tube assembly 3 contacts the front end limiting surface 20204 of the inner tube, axial front end limiting is formed. The axial rear end of the core barrel inner tube assembly 3 is clamped by the radial extension of the rear end locking tongue 20207 of the inner tube to form axial rear end limiting. Drilling continues and step three is repeated.

[0129] When a borehole design has continuous sealed pressure core taking, the operations of steps three, four, and five can be repeated.

[0130] Step six, pulling out the drill:

[0131] After the coring operation is completed, the drill is pulled out of the hole. The coal bodies in the multiple core barrel inner tube assemblies 3 can form continuous in-situ coal samples in the order of sampling for subsequent experimental analysis.

Claims

1. A medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams, characterized in that: The device comprises, from front to back in the axial direction, an electrically driven openable and closable drill bit (1) which is coaxially arranged and hollow inside, a core barrel outer tube assembly (2), and a signal transmission drill rod (4); a core barrel inner tube assembly (3) which is hollow inside is coaxially installed inside the core barrel outer tube assembly (2); The electrically driven openable and closable drill bit (1) is connected to the signal transmission drill rod (4) via an insulated wire or a conductive block, thereby realizing the opening or closing of the electrically driven openable and closable drill bit (1); The outer tube assembly (2) of the core barrel is connected to the signal transmission drill rod (4) via an insulated wire or a conductive block, thereby being able to achieve axial limitation of the inner tube assembly (3) of the core barrel; The core barrel inner tube assembly (3) is connected to the signal transmission drill rod (4) via an insulated wire or a conductive block, thereby realizing the opening or closing of the axial ends of the internal cavity of the core barrel inner tube assembly (3); The outer side wall of the signal transmission drill rod (4) is also coaxially and integrally provided with a spirally wound drill rod wing (404).

2. The medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams according to claim 1, characterized in that: The electrically driven openable and closable drill bit (1) comprises a drill bit body (101), wherein a central through hole (102) is coaxially opened in the drill bit body (101) and passes through both axial ends, wherein the diameter of the axial front section of the central through hole (102) is smaller than the diameter of the axial rear section of the central through hole (102), and the step surface at the connection between the axial front section of the central through hole (102) and the axial rear section of the central through hole (102) serves as a first limiting surface (103) at the front end of the outer tube; The axial front end of the drill body (101) is also integrally provided with a plurality of fixed blades (104), and the plurality of fixed blades (104) are evenly distributed along the circumferential direction on the outer edge of the axial front end of the drill body (101); A rear conductive block (107) and a rear insulating wrapping layer (108) are embedded and installed on the axial rear end surface of the drill body (101). The rear insulating wrapping layer (108) isolates the rear conductive block (107) from the drill body (101). The rear conductive block (107) is connected to the driving motor of the electrically driven openable and closable drill bit (1) through an insulated wire.

3. The medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams according to claim 2, characterized in that: The center of the axial front end of the drill body (101) is also provided with two rotatable blades (105) in an axially symmetrical manner. When the two rotatable blades (105) are closed, the axial front end of the central through hole (102) is sealed. The axial front end of the drill body (101) is also provided with a blade rotation shaft (106). The blade rotation shaft (106) corresponds to the rotatable blades (105) one by one. The two rotatable blades (105) are installed on the drill body (101) through the corresponding blade rotation shaft (106). The two rotatable blades (105) can also rotate 90 degrees around the corresponding blade rotation shaft (106) under the drive of the drive motor of the electrically driven openable and closable drill bit (1).

4. The medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams according to claim 2, characterized in that: The core tube outer tube assembly (2) comprises, in order from front to back in the axial direction, an outer tube front end male connector (201), a core tube outer tube body (202) and an outer tube rear end female connector (203) which are coaxially arranged in an integrated manner; The outer tube front end male connector (201) comprises a cylindrical outer tube front end male connector body (20101), the axial front end of the outer tube front end male connector body (20101) is axially limited by a first limiting surface (103) at the outer tube front end, the outer tube front end male connector body (20101) is connected to the drill bit body (101) via an external thread, and an axially penetrating first outer tube channel (20102) is coaxially opened in the outer tube front end male connector body (20101), and the axial front end of the first outer tube channel (20102) is connected to the axial rear end of the central through hole (102); The outer tube body (202) of the core barrel comprises a cylindrical outer tube body (20201), the axial front end of the outer tube body (20201) being limited by the axial rear end face of the drill bit body (101), and a plurality of outer tube front end conductive units (20202) being embedded and evenly distributed along the circumferential direction on the axial front end face of the outer tube body (20201), and the outer tube front end conductive units (20202) being able to contact with the rear handle conductive block (107) to achieve mutual communication; A second outer tube channel (20203) is coaxially opened in the outer tube body (20201), and the axial front end of the second outer tube channel (20203) is connected to the axial rear end of the first outer tube channel (20102). The step surface of the second outer tube channel (20203) near the axial front end is the inner tube front end limiting surface (20204). A core tube inner tube assembly (3) is also installed in the second outer tube channel (20203). The maximum inner diameter of the second outer tube channel (20203) is equal to the maximum outer diameter of the core tube inner tube assembly (3).

5. The medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams according to claim 4, characterized in that: A plurality of outer tube inner wall conductive units (20205) are also embedded on the inner wall of the outer tube body (20201), and an electromagnetic valve assembly (20206) and an inner tube rear end locking tongue (20207) are also embedded on the inner wall of the outer tube body (20201) near the axial rear end. The electromagnetic valve assembly (20206) can drive the inner tube rear end locking tongue (20207) to extend and retract along the radial direction of the second outer tube channel (20203), thereby limiting the axial rear end of the core barrel inner tube assembly (3); The outer tube rear end female connector (203) comprises an outer tube rear end female connector body (20301), a third outer tube channel (20302) is coaxially provided in the outer tube rear end female connector body (20301), the axial front end of the third outer tube channel (20302) is connected to the axial rear end of the second outer tube channel (20203), and a stepped transmission rod front end limiting surface (20304) is also provided in the third outer tube channel (20302).

6. The medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams according to claim 5, characterized in that: The outer tube rear end female connector body (20301) is also provided with an outer tube rear end conductive unit (20303) embedded and evenly distributed along the circumferential direction on the axial rear end surface thereof. The outer tube rear end conductive unit (20303) comprises an outer tube rear end conductive block (2030301). The outer tube rear end conductive block (2030301) is isolated from the outer tube rear end female connector body (20301) by the outer tube rear end insulating wrapping layer (2030302). The outer tube rear end conductive block (2030301) can be in contact with the signal transmission drill pipe (4) to achieve mutual communication. The structure of the outer tube front end conductive unit (20202) is the same as the structure of the outer tube rear end conductive unit (20303); The outer tube inner wall conductive unit (20205) comprises an outer tube inner wall conductive block (2020501), and the outer tube inner wall conductive block (2020501) is isolated from the outer tube body (20201) by an outer tube inner wall insulating wrapping layer (2020502); The conductive block of the outer tube front end conductive unit (20202), the outer tube inner wall conductive block (2020501), the solenoid valve assembly (20206) and the outer tube rear end conductive block (2030301) are interconnected through insulated wires and are insulated from the outer tube front end male connector body (20101), the outer tube body (20201) and the outer tube rear end female connector body (20301).

7. The medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams according to claim 6, characterized in that: The core tube inner tube assembly (3) comprises, from front to back along the axial direction, an inner tube front end electrically controlled valve (301), an inner tube body (302) of the core tube, an inner tube rear end electrically controlled valve (303), and a salvaging mechanism (304) which are coaxially arranged and threadedly connected; the structure of the inner tube front end electrically controlled valve (301) is the same as that of the inner tube rear end electrically controlled valve (303), and the two are axially symmetrically arranged at the axial ends of the inner tube body (302) of the core tube; The inner tube front end electrically controlled valve (301) includes a front end valve body shell (30101), and the front end valve body shell (30101) includes an integrated coaxially arranged front end valve body seat (3010101) and a front end valve body (3010102) in sequence from front to back along the axial direction; the axial front end of the front end valve body seat (3010101) is axially limited by the inner tube front end limiting surface (20204), the outer diameter of the front end valve body seat (3010101) is equal to the maximum inner diameter of the second outer tube channel (20203), and the outer side wall of the front end valve body seat (3010101) is also embedded with Multiple inner tube front end conductive units (30102), the multiple inner tube front end conductive units (30102) are evenly distributed along the circumferential direction, each inner tube front end conductive unit (30102) includes an inner tube front end conductive block (3010201), the inner tube front end conductive block (3010201) is isolated from the front end valve body seat (3010101) by the inner tube front end insulating wrapping layer (3010202); the inner tube front end conductive block (3010201) also has a one-to-one correspondence with the outer tube inner wall conductive block (2020501) near the axial front end of the outer tube body (20201), and they are connected to each other; The front end valve body (3010102) is also coaxially provided with an axially penetrating front end valve body channel (30103), which extends axially forward through the interior of the front end valve body seat (3010101) and is connected to the axial rear end of the third outer tube channel (20302); the cavity of the front end valve body channel (30103) at the middle section of the front end valve body (3010102) is a spherical cavity, and a front end spherical valve core (30104) is also installed in the spherical cavity. A front end valve core drive motor (30105) is also installed on the front end valve body (3010102), and the front end valve core drive motor (30105) can drive the front end spherical valve core (30104) to open or close the front end valve body channel (30103).

8. The medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams according to claim 7, characterized in that: The inner tube body (302) of the core barrel comprises an inner tube body (30201), an inner tube body channel (30202) is coaxially opened in the inner tube body (30201), the diameter of the inner tube body channel (30202) is equal to the diameter of the front end valve body channel (30103), and the axial front end of the inner tube body channel (30202) is connected to the axial rear end of the front end valve body channel (30103); The inner tube rear end electrically controlled valve (303) comprises a rear end valve body channel, the axial front end of the rear end valve body channel is connected to the axial rear end of the inner tube body channel (30202); the axial rear end of the rear end valve body seat of the inner tube rear end electrically controlled valve (303) can be axially limited by the inner tube rear end locking tongue (20207), and the rear end valve body seat of the inner tube rear end electrically controlled valve (303) is also connected to the axial front end of the coaxially arranged salvage mechanism (304) via an internal thread; the rear end valve body seat of the inner tube rear end electrically controlled valve (303) is also provided with an inner tube rear end conductive block, and the inner tube rear end conductive block is also in one-to-one correspondence with the outer tube inner wall conductive block (220501) near the axial rear end of the outer tube body (20201) and is connected to each other; The inner tube front end conductive block (3010201), the front end valve core drive motor (30105), the inner tube rear end conductive block of the inner tube rear end electric control valve (303), and the rear end valve core drive motor of the inner tube rear end electric control valve (303) are connected by insulating wires, and are all isolated from the front end valve body shell (30101), the inner tube body (30201), and the rear end valve body shell of the inner tube rear end electric control valve (303).

9. The medium-free continuous pressure-maintaining and sealed coring drilling tool for crushed soft coal seams according to claim 6, characterized in that: The signal transmission drill rod (4) comprises a transmission rod male connector (401), a transmission rod tube (402) and a transmission rod female connector (403) which are coaxially arranged and sequentially connected from front to back along the axial direction; The transmission rod male connector (401) comprises a transmission rod male connector body (40101), which is connected to the female connector body (20301) at the rear end of the outer tube via an external thread; an axially penetrating transmission rod male connector channel (40102) is coaxially provided inside the transmission rod male connector body (40101), and the axial front end of the transmission rod male connector channel (40102) is connected to the third outer tube channel (20302); A transmission rod front end conductive block (40103) is embedded and installed on the end surface of the transmission rod male connector (401) near the inner end of the transmission rod male connector body (40101). The transmission rod front end conductive block (40103) is insulated and protected by the transmission rod front end insulating wrapping layer (40104). The transmission rod front end conductive block (40103) can contact and communicate with the outer tube rear end conductive block (2030301). The transmission rod tube body (402) comprises a transmission rod tube body main body (40201), and an axially penetrating transmission rod tube body channel (40202) is coaxially opened inside the transmission rod tube body main body (40201); The transmission rod female joint (403) includes a transmission rod female joint body (40301), and an axially penetrating transmission rod rear end channel (40302) is coaxially opened in the transmission rod female joint body (40301). The axial front end of the transmission rod rear end channel (40302) is connected to the axial rear end of the transmission rod male joint channel (40102) through the transmission rod tube body channel (40202). The inner diameter of the transmission rod rear end channel (40302), the inner diameter of the transmission rod tube body channel (40202), and the inner diameter of the transmission rod male joint channel (40102) are all greater than the maximum outer diameter of the core barrel inner tube assembly (3); The axial rear end face of the transmission rod female connector body (40301) is also embedded with a transmission rod rear end conductive block (40303), and the transmission rod rear end conductive block (40303) is insulated and protected by the transmission rod rear end insulating wrapping layer (40304); the transmission rod rear end conductive block (40303) is also connected to the transmission rod front end conductive block (40103) through an insulated wire.

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