Rotary sealing device for underground coal mine nearly-horizontal drilling grooving drill rod

Abstract

The utility model belongs to the field of drilling, and discloses a rotary sealing device for an underground coal mine nearly-horizontal drilling grooving drill rod, in the drilling process, a hydraulic pump station provides larger hydraulic pressure to extrude a rubber core, and meanwhile, under the action of a bearing, the sealing rubber core rotates together with the drill rod. Compared with a traditional method, the rotary sealing device has the advantages that larger pressure can be used for extruding the sealing rubber core, the sealing effect is better, friction between the drill rod and the rubber core is reduced due to the fact that the rotary sealing device synchronously rotates and axially moves along with the drill rod, the sealing performance is improved, production safety is guaranteed, meanwhile, the service life of the sealing rubber core is prolonged, and the service life of the drill rod is prolonged. The resource cost is saved, and the production continuity is ensured.

Description

Technical Field

[0001] The utility model belongs to the field of drilling, in particular to a rotary sealing device for a grooved drill rod used for near-horizontal drilling in underground coal mines. Background Art

[0002] In coal mining, sub-horizontal drilling is an important method for gas extraction, water exploration and drainage, and the detection of hidden disaster-causing factors. Currently, packing seals are commonly used during the drilling process to prevent leakage of drilling fluid from the connection between the drill pipe and the orifice pipe. As mining depth and scale continue to expand, the requirements for drilling technology are also increasing.

[0003] Existing composite drilling methods (a novel drilling process in which a screw drill rotates the drill bit while a power head rotates the drill rod) combined with grooved drill rods in near-horizontal drilling can effectively improve slag removal efficiency, enhance drilling efficiency, and enhance drilling stability, leading to increasing frequency of use. However, packing seals struggle to achieve a seal in composite drilling with grooved drill rods. Seal failure not only leads to drilling fluid leakage and contamination of the underground working environment, but can also cause safety incidents and serious consequences such as gas leaks. Furthermore, frequent replacement of sealing components increases operating costs, reduces drilling efficiency, and seriously impacts the continuity and economic viability of coal mine production. Utility Model Content

[0004] The purpose of the utility model is to provide a rotary sealing device for grooved drill rods used in near-horizontal drilling in coal mines, so as to solve the problem in the prior art that grooved drill rod composite drilling is difficult to achieve sealing, resulting in low drilling efficiency and affecting the continuity and economy of coal mine production.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A rotary sealing device for a grooved drill rod for near-horizontal drilling in a coal mine, comprising a rotary sealing device slidably arranged on a guide assembly, the rotary sealing device comprising a cylindrical sealing shell; an extrusion chamber and a piston chamber are respectively provided on the left and right sides of the interior of the sealing shell; a first thrust bearing and a rotating sleeve are coaxially rotated from left to right inside the extrusion chamber; a sealing rubber core and a second thrust bearing are provided inside the rotating sleeve from left to right.

[0007] It also includes a pushing piston; the piston head of the pushing piston is slidably arranged in the rotating sleeve and contacts the right end face of the second thrust bearing, and the piston rod of the pushing piston is slidably arranged inside the piston cavity; the outer diameter of the piston head of the pushing piston is larger than the inner diameter of the piston cavity.

[0008] The first thrust bearing, the sealing rubber core, the second thrust bearing and the pushing piston have the same inner diameter, forming a through hole; the drill rod can be inserted into the through hole.

[0009] An oil filling port is provided on the right side of the sealing shell. The external hydraulic device can push the piston to the left to squeeze the sealing rubber core by injecting hydraulic oil into the oil filling port, thereby deforming the sealing rubber core and holding the drill rod tightly.

[0010] The utility model also has the following features:

[0011] Furthermore, an annular sealing plate is coaxially arranged in the sealing shell, and the annular sealing plate is located at the right end of the extrusion chamber; the inner diameter of the sealing plate is smaller than the piston chamber; the cavity formed between the left end face of the sealing plate, the inner wall of the sealing shell, the right end face of the rotating sleeve and the corresponding positions of the outer wall of the pushing piston is the oil filling chamber; the oil filling port is connected to the oil filling chamber.

[0012] The piston rod that pushes the piston is sealed and slides through the sealing plate into the interior of the piston cavity.

[0013] Furthermore, a flange is coaxially connected to the right side of the sealing shell of the rotary sealing device.

[0014] The rotary sealing device is fixedly connected to one end of the telescopic tube through a flange, the left end of the drill rod is connected to an external drilling rig, and the right end of the drill rod passes through the telescopic tube and is connected to the orifice casing.

[0015] Furthermore, the telescopic tube is a bellows.

[0016] Furthermore, the guide assembly includes a support seat.

[0017] The support seat is provided with a guide rail, a connecting plate is provided on the left side of the guide rail, and the guide assembly is connected to the external drilling rig through the connecting plate;

[0018] The guide rail extends in the left-right direction, and a guide slider is slidably provided on the guide rail. The shape of the guide slider matches the shape of the outer wall of the sealing shell of the rotary sealing device.

[0019] Furthermore, a fixing plate is provided on the sealing shell of the rotary sealing device, and the rotary sealing device is fixedly connected to the guide slider via the fixing plate.

[0020] Furthermore, the left side of the sealing shell of the rotary sealing device is connected to an end cover with a hole in the middle.

[0021] Furthermore, the orifice sleeve and the telescopic tube are connected via a tee pipe.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] (I) The utility model provides a rotary seal connection for grooved drill pipes used in near-horizontal drilling in coal mines. During drilling, a hydraulic pump station provides greater hydraulic pressure to squeeze the rubber core. Simultaneously, under the action of the bearing, the rubber core rotates along with the drill pipe. Compared to traditional methods, this arrangement not only allows for greater pressure to squeeze the rubber core, resulting in a better sealing effect, but also reduces friction between the drill pipe and the rubber core because the rotary seal device rotates and moves axially synchronously with the drill pipe. This improves sealing performance and ensures production safety while extending the service life of the rubber core, saving resource costs and ensuring production continuity.

[0024] (II) The utility model of the rotary sealing device for grooved drill rods for near-horizontal drilling in coal mines adopts a combination of a slide plate and a guide rail, and is equipped with a telescopic tube. When the drill rod is drilling, the rotary sealing device can move along the guide rail with the drill rod, further improving the applicability of the device and making it suitable for large-scale use and promotion in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a cross-sectional view of the rotary sealing device in the present utility model;

[0026] Figure 2 This is a schematic structural diagram of the guide device in the utility model;

[0027] Figure 3 The utility model is a schematic diagram of a rotary sealing device for a grooved drill rod used for near-horizontal drilling in underground coal mines.

[0028] The meaning of each number in the figure is:

[0029] 1. Guide assembly; 2. Rotary seal device; 3. Drill pipe; 4. Telescopic tube; 5. Orifice casing; 6. Support seat; 7. Guide rail; 8. Connecting plate; 9. Guide slider; 10. Target rock formation;

[0030] 201. Sealing housing; 202. First thrust bearing; 203. Rotating sleeve; 204. Sealing rubber core; 205. Second thrust bearing; 206. Push piston; 207. Oil filling port; 208. Sealing plate; 209. Flange; 210. Fixed plate; 211. End cover. DETAILED DESCRIPTION

[0031] It should be noted that, unless otherwise specified, all components in the present invention are components known in the prior art. For example, the flange plate is a known and commonly used flange plate.

[0032] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made on the basis of the technical solution of this application fall within the scope of protection of the present invention.

[0033] like Figures 1 to 3 As shown, a rotary sealing device for a grooved drill pipe for near-horizontal drilling in a coal mine underground includes a rotary sealing device 2 slidably arranged on a guide assembly 1, and the rotary sealing device 2 includes a cylindrical sealing shell 201; the left and right sides of the sealing shell 201 are respectively an extrusion chamber and a piston chamber; a first thrust bearing 202 and a rotating sleeve 203 are coaxially rotated from left to right inside the extrusion chamber; a sealing rubber core 204 and a second thrust bearing 205 are arranged inside the rotating sleeve 203 from left to right.

[0034] It also includes a pushing piston 206; the piston head of the pushing piston 206 is slidably arranged in the rotating sleeve and contacts the right end face of the second thrust bearing 205, and the piston rod of the pushing piston 206 is slidably arranged inside the piston cavity; the outer diameter of the piston head of the pushing piston 206 is larger than the inner diameter of the piston cavity, which plays an axial limiting role on the piston head of the pushing piston 206.

[0035] The first thrust bearing 202 , the sealing rubber core 204 , the second thrust bearing 205 and the pushing piston 206 have the same inner diameter, forming a through hole; the drill rod 3 can be inserted into the through hole.

[0036] An oil inlet 207 is provided on the right side of the sealed housing 201. By injecting hydraulic oil into the oil inlet 207, the external hydraulic device can push the piston 206 to the left to squeeze the sealing rubber core 204, thereby deforming the sealing rubber core 204 and tightly gripping the drill rod 3. An oil inlet 207 is provided on the right side of the sealed housing 201. By injecting hydraulic oil into the oil inlet 207, the external hydraulic device can push the piston 206 to squeeze the sealing rubber core 204, thereby deforming the sealing rubber core 204 and tightly gripping the drill rod 3.

[0037] Specifically, according to conventional selection in the art, the sealing rubber core 204 is made of elastic material, such as polytetrafluoroethylene.

[0038] The following provides a specific implementation of the main materials and performance parameters of the sealant core 204:

[0039] The material of the sealing rubber core 204 is nitrile rubber (NBR).

[0040] To improve the elasticity and friction resistance of nitrile rubber (NBR), we optimized the vulcanization system, reinforcing fillers, and functional additives. The following are the specific additive solutions, dosages, and performance improvement data:

[0041] Optimal formula combination (parts by weight):

[0042] NBR (acrylonitrile content 33%): 100

[0043] Peroxide DCP: 1.2

[0044] Cross-linking agent TAIC: 0.8

[0045] High wear-resistant carbon black N110:45

[0046] Nano-SiO2: 6 (KH-570 coupling agent 1)

[0047] Ester softener DOS: 10

[0048] Antioxidant 4010NA: 2

[0049] Graphene: 1.5 (SDS dispersant 0.5)

[0050] Comprehensive performance improvement data is shown in Table 1 Performance Improvement Data Table:

[0051] Table 1 Performance improvement data table

[0052]

[0053] The principle of the sealant core 204 holding the drill rod 3 is further described below:

[0054] When the drill rod needs to be clamped, the hydraulic oil pushes the piston 206 to move to the left to squeeze the sealing rubber core 204. Since the sealing rubber core 204 is made of elastic material, it will shorten in the axial direction and become thicker after being squeezed, thereby generating a clamping force on the drill rod 3 to clamp the drill rod 3. At the same time, it will also generate a force on the rotating sleeve 203, so that the rotating sleeve 203, the sealing rubber core 204 and the drill rod 3 form a whole.

[0055] During drilling construction, high-pressure oil is injected into the oil injection nozzle of the rotary sealing device through a small hydraulic pump station (or hydraulic oil is taken from the drilling rig) to squeeze the sealing rubber core 204.

[0056] Specifically, according to conventional selection in the art, the sealing rubber core 204 may be made of a polytetrafluoroethylene material having good flexibility, which can penetrate into the groove of the drill rod 3 to achieve sealing.

[0057] At the same time, the sealing rubber core 204, together with the rotating sleeve 203, rotates with the drill rod 3 with the help of the first thrust bearing 202 and the second thrust bearing 205, and the rotary sealing device 2 can slide on the guide assembly during drilling construction. Therefore, after the sealing rubber core 204 holds the grooved drill rod, there is no relative movement between it and the drill rod 3, which achieves sealing while reducing the wear of the sealing rubber core 204.

[0058] Specifically, in this field, Ø73mm and Ø89mm drilling tool systems are commonly used underground in coal mines. The rotary sealing device 2 in this embodiment is designed based on the Ø89mm spiral drill rod and is optimized for the Ø89mm grooved drill rod. According to field tests, the dynamic seal is leak-free when the manual hydraulic pump pressure reaches 1.5~2MPa.

[0059] As an optional solution, an annular sealing plate 208 is coaxially disposed within the sealing housing 201 and is located at the right end of the extrusion chamber. The inner diameter of the sealing plate 208 is smaller than the piston chamber. The cavity formed between the left end face of the sealing plate, the inner wall of the sealing housing 201, the right end face of the rotating sleeve 203, and the corresponding positions on the outer wall of the pushing piston 206 serves as the oil filling chamber. The sealing plate 208 is used to ensure the sealing of the oil filling chamber, and the oil filling port 207 is connected to the oil filling chamber.

[0060] The piston rod of the piston 206 is sealed and slidably passes through the sealing plate 208 into the interior of the piston chamber.

[0061] As a preferred solution, a flange 209 is coaxially connected to the right side of the sealing shell 201 of the rotary sealing device 2 .

[0062] The rotary sealing device 2 is fixedly connected to one end of the telescopic tube 4 through the flange 209 , and the other end of the drill rod 3 passes through the telescopic tube 4 and is connected to the orifice casing 5 .

[0063] Furthermore, the orifice sleeve 5 is connected to the telescopic tube 4 through a tee pipe.

[0064] Specifically, the telescopic tube 4 is a bellows.

[0065] Furthermore, the travel of the telescopic tube 4 can be adjusted by those skilled in the art according to the length of the external drill head guide rail, with the two being kept consistent as the basic principle. In this embodiment, a specific numerical value is selected, and the travel of the telescopic tube 4 is 1.2m.

[0066] A specific working process of this device is given below:

[0067] First, a hole is drilled using conventional methods in the art: a drilling rig is fixed, a mud pump is connected, a drill pipe 3 is added, the hole is opened and expanded, a hole casing 5 is lowered, and then the hole is fixed with cement slurry and allowed to solidify until it is completely solidified.

[0068] Next, connect and install the guide assembly 1 to the drilling rig, install the rotary sealing device 2 on the guide assembly 1, and then connect the telescopic tube 4 to the orifice casing 5. Fine-tune the position of the drilling rig so that the rotary sealing device 2 is connected to the telescopic tube 4 and the rotary sealing device 2 is on the side closest to the drilling rig (away from the orifice).

[0069] The rotary sealing device 2 is provided with a dedicated small hydraulic pump station to supply oil, or a hydraulic oil channel can be separated from the drilling rig to connect to the rotary sealing device 2 .

[0070] Then comes the formal drilling: start the hydraulic pump station, and inject high-pressure hydraulic oil into the rotary sealing device 2, so that it holds the drill pipe 3 tightly to achieve sealing. During drilling, the rotary sealing device 2 holds the drill pipe 3 tightly and moves forward. The drilling fluid enters the bottom of the hole from the inner hole of the drill pipe 3 to drive the screw drill to drill, and then returns from the annulus between the drill pipe 3 and the wall of the borehole. After reaching the hole mouth, it is discharged from the third channel of the tee pipe. After drilling one stroke, shut down the mud pump, shut down the hydraulic pump station and drain the oil, so that the rotary sealing device 2 temporarily loosens the drill pipe 3.

[0071] With the help of the reaction force of the telescopic tube 4, the rotary sealing device 2 is manually reset to the initial position, and then the hydraulic pump station is turned on to make the rotary sealing device 2 hold the drill pipe again, and the drill pipe 3 is added to carry out the next round of drilling.

[0072] The following further provides key points for controlling the clearance between the sealing plate 208 and the piston rod based on the common knowledge in the art:

[0073] (1) In the rotary sealing device 2, the specific value of the clearance between the sealing plate 208 and the piston rod needs to be adjusted according to the equipment specifications (such as nominal diameter, working pressure) and working conditions. The principle is to meet the minimum leakage requirements under dynamic sealing conditions;

[0074] (2) In actual operation in this field, a gap that is too small will lead to increased frictional heat generation and accelerated wear, while a gap that is too large will easily cause medium leakage. Based on the above problems, this embodiment provides a specific gap control method: the gap is designed to be 0.05% to 0.1% of the piston rod diameter. For example, for a piston rod with a diameter of 100 mm, the gap is controlled to be 0.05 to 0.1 mm.

[0075] As a preferred solution, the guide assembly 1 includes a support seat 6 .

[0076] A guide rail 7 is provided on the support seat 6 , and a connecting plate 8 is provided on the left side of the guide rail 7 . The guide assembly 1 is connected to an external drilling rig via the connecting plate 8 .

[0077] The guide rail 7 extends in the left-right direction. A guide slider 9 is slidably provided on the guide rail 7 . The shape of the guide slider 9 matches the shape of the outer wall of the sealing shell 201 of the rotary sealing device 2 .

[0078] Further preferably, a fixing plate 210 is provided on the sealing housing 201 of the rotary sealing device 2 , and the rotary sealing device 2 is fixedly connected to the guide slider 9 via the fixing plate 210 , thereby enhancing the connection strength between the rotary sealing device 2 and the guide slider 9 .

[0079] As a preferred solution, an end cover 211 with a central opening is connected to the left side of the sealing housing 201 of the rotary sealing device 2. The opening on the end cover 211 is used for the drill rod 3 to pass through it.

Claims

1. A rotary sealing device for grooved drill pipe for near-horizontal drilling in coal mines, characterized in that: The invention comprises a rotary sealing device (2) slidably arranged on a guide assembly (1), wherein the rotary sealing device (2) comprises a cylindrical sealing shell (201); the left and right sides of the sealing shell (201) are respectively an extrusion chamber and a piston chamber; the extrusion chamber is provided with a first thrust bearing (202) and a rotating sleeve (203) coaxially rotating from left to right; the rotating sleeve (203) is provided with a sealing rubber core (204) and a second thrust bearing (205) from left to right; It also includes a pushing piston (206); the piston head of the pushing piston (206) is slidably arranged in the rotating sleeve (203) and contacts the right end surface of the second thrust bearing (205); the piston rod of the pushing piston (206) is slidably arranged inside the piston cavity; the outer diameter of the piston head of the pushing piston (206) is larger than the inner diameter of the piston cavity; The first thrust bearing (202), the sealing rubber core (204), the second thrust bearing (205) and the pushing piston (206) have the same inner diameter, forming a through hole; the drill rod (3) can be inserted into the through hole; An oil filling port (207) is provided on the right side of the sealing housing (201). The external hydraulic device can push the piston (206) to the left to squeeze the sealing rubber core (204) by injecting hydraulic oil into the oil filling port (207), thereby deforming the sealing rubber core (204) and holding the drill rod (3).

2. The rotary sealing device for grooved drill rods for sub-horizontal drilling in coal mines according to claim 1, characterized in that: An annular sealing plate (208) is coaxially arranged in the sealing housing (201), and the annular sealing plate (208) is located at the right end of the extrusion chamber; the inner diameter of the sealing plate (208) is smaller than that of the piston chamber; The cavity formed between the left end surface of the sealing plate (208), the inner wall of the sealing shell (201), the right end surface of the rotating sleeve (203) and the outer wall of the pushing piston (206) at corresponding positions is the oil filling cavity, and the oil filling port (207) is connected to the oil filling cavity; The piston rod of the pushing piston (206) is sealed and slides through the sealing plate (208) into the interior of the piston cavity.

3. The rotary sealing device for grooved drill rods for sub-horizontal drilling in coal mines according to claim 2, characterized in that: The right side of the sealing housing (201) of the rotary sealing device (2) is coaxially connected to a flange (209); The rotary sealing device (2) is fixedly connected to one end of the telescopic tube (4) via a flange (209), the left end of the drill rod (3) is connected to an external drilling rig, and the right end of the drill rod (3) passes through the telescopic tube (4) and is connected to the orifice casing (5).

4. The rotary sealing device for grooved drill rods for sub-horizontal drilling in coal mines according to claim 3, characterized in that: The telescopic tube (4) is a bellows.

5. The rotary sealing device for grooved drill rods for sub-horizontal drilling in coal mines according to claim 4, characterized in that: The guide assembly (1) comprises a support seat (6); A guide rail (7) is provided on the support seat (6), a connecting plate (8) is provided on the left side of the guide rail (7), and the guide assembly (1) is connected to an external drilling rig via the connecting plate (8); The guide rail (7) extends in the left-right direction, and a guide slider (9) is slidably provided on the guide rail (7). The shape of the guide slider (9) matches the shape of the outer wall of the sealing shell (201) of the rotary sealing device (2).

6. The rotary sealing device for grooved drill rods for sub-horizontal drilling in coal mines according to claim 5, characterized in that: A fixed plate (210) is provided on the sealing housing (201) of the rotary sealing device (2), and the rotary sealing device (2) is fixedly connected to the guide slider (9) via the fixed plate (210).

7. The rotary sealing device for grooved drill rods for sub-horizontal drilling in coal mines according to claim 6, characterized in that: The left side of the sealing shell (201) of the rotary sealing device (2) is connected to an end cover (211) with a hole in the middle.

8. The rotary sealing device for grooved drill rods for sub-horizontal drilling in coal mines according to claim 7, characterized in that: The orifice sleeve (5) and the telescopic tube (4) are connected via a tee pipe.

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