A special connecting device for goaf pipeline sheath in mines

Abstract

The utility model discloses a kind of special connecting device for mining goaf pipeline sheath, belong to coal mine safety equipment field.The device is made of first, second connecting head sheet metal (1,2) by hinge (4) and fixed shaft (5) hinged into openable and closable cylindrical hoop, free end is locked with fastening bolt (6);Sheet metal butt end surface is provided with nitrile rubber gasket (3) and plastic-elastic composite sealing ring (7), form double seal that is automatically enhanced with external pressure;When installing, it is not necessary to professional tool, 3 min can complete one connection, pressure bearing 30bar, explosion-proof grade ExdIMb.The utility model solves the problem that traditional flange, sleeve or welding mode is under the condition of dynamic deformation in goaf Sealing failure, insufficient compensation, maintenance difficulty, can be widely used in coal mine underground beam tube, temperature measuring optical cable and other pipeline fast connection and protection.

Description

Technical Field

[0001] This utility model relates to the field of coal mine safety equipment technology, and in particular to a special connecting device for pipeline sheathing in mining goaf areas. Background Technology

[0002] During the recovery process of coal mine goaf areas, the surface and surrounding rock continuously move, requiring pipelines such as bundled tubes and temperature-measuring optical cables laid within them to undergo axial expansion and contraction and radial displacement with the rock strata. Existing technologies mainly employ three connection methods:

[0003] Flange connection: relies on flat gasket for sealing. Under the displacement of rock strata, the bolts are easy to loosen, the sealing pressure drops rapidly, resulting in gas and water seepage. The maintenance cycle is less than 6 months.

[0004] Sleeve-type connection: can only provide ≤10% axial compensation (approximately ±10mm), and has weak shear resistance; it will be pulled off once the base plate bulges.

[0005] Welded connections: Although the seal is reliable, they cannot adapt to dynamic deformation, the weld is prone to fatigue cracks, and there is a high risk of open flame in the well. When replacing them, the pipeline must be cut off, which is time-consuming and costly.

[0006] Therefore, there is an urgent need for a pipeline sheath connection device that is "reliably sealed, provides large displacement compensation, requires no hot work, and can be repeatedly disassembled and reassembled" at coal mine sites. Utility Model Content

[0007] The purpose of this utility model is to provide a special connection device for pipeline sheathing in mining goaf areas, thereby solving the aforementioned problems existing in the prior art.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] A special connection device for pipeline sheathing in mining goaf areas, comprising:

[0010] The first connector sheet metal and the second connector sheet metal are hinged at their fixed ends;

[0011] Fixed shafts are respectively provided along the width direction of the free ends of the first connector sheet metal and the second connector sheet metal; the two fixed shafts of the first connector sheet metal and the second connector sheet metal are locked by fastening bolts to form a cylindrical clamp structure that can be repeatedly opened and closed.

[0012] The nitrile rubber sealing gasket is set along the inner arc direction of the cylindrical clamp structure of the first connector sheet metal and the second connector sheet metal, and the two ends of the nitrile rubber sealing gasket extend from the free ends of the first connector sheet metal and the second connector sheet metal, respectively.

[0013] In some specific embodiments, both the first connector sheet metal and the second connector sheet metal are semi-circular arc-shaped sheet metal integrally cast from ductile iron, with a wall thickness of 5-8mm and an inner diameter that is clearance-fitted with the outer diameter of the mining pipeline sheath.

[0014] In some specific embodiments, the hinge has a double-blade structure, with the blades respectively embedded into the fixed ends of the first connector sheet metal and the second connector sheet metal, with an embedding depth of not less than 10mm.

[0015] In some specific embodiments, 2 to 4 sets of fastening bolts are evenly distributed along the edge of the free end of the connector sheet metal, the center line of the bolts is parallel to the axis of the cylindrical clamp, and the bolt head is sunk into the countersunk hole of the ductile iron bearing flange.

[0016] In some specific embodiments, the nitrile rubber sealing gasket is an annular flat gasket with a thickness of 2-3 mm.

[0017] In some specific embodiments, the free end faces of the first connector sheet metal and the second connector sheet metal are provided with a mating positioning stop, which is a 3mm×3mm concave-convex step for circumferential positioning and to prevent misalignment and shearing.

[0018] In some specific embodiments, bolt holes are provided along the length of the fixed shaft for connection with fastening bolts.

[0019] In some specific embodiments, the device has a symmetrical two-half structure. No special tools are required for installation. The connection or disassembly of the pipeline sheath can be completed within 3 minutes simply by tightening and loosening the bolts.

[0020] The beneficial effects of this utility model are:

[0021] Large compensation capacity: axial ±35mm, radial deflection ±15°, which is 3.5 times that of traditional sleeves. It can completely cover the dynamic deformation of the goaf over a year and prevent pull-out, twisting and leakage.

[0022] Self-reinforcing seal: The plastic-elastic composite sealing ring expands radially as the external pressure increases from 0.6MPa to 2.4MPa, achieving "tighter with pressure". It can withstand 30 bar pressure for 30 minutes without leakage, and its service life is extended from 6 months to 24 months.

[0023] Highly efficient installation: The two-part clamp structure and pre-positioned hinges allow for connection with just 2-4 bolts tightened or loosened. A single person can complete the operation in 3 minutes, increasing efficiency by 80%. No welding or power tools are required, complying with coal mine fire prevention regulations.

[0024] Easy maintenance: Disassembly only requires removing the fastening bolts and opening the clamp to replace the seals or move the pipe, greatly reducing downtime for maintenance.

[0025] Safety and explosion protection: The integral ductile iron pressure-bearing flange design has passed GB3836.1-2021ExdIMb explosion protection certification and can be used safely in gas environments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a special connecting device for pipeline sheathing in mining goaf areas according to this utility model;

[0027] Figure 2 This is a schematic diagram of another example of a special connecting device for pipeline sheathing in mining goaf areas according to this utility model.

[0028] In the attached diagram: 1. First connector sheet metal; 2. Second connector sheet metal; 3. Nitrile rubber sealing gasket; 4. Hinge; 5. Fixed shaft; 6. Fastening bolt. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0030] Reference Figure 1 and Figure 2 The shown is a special connection device for pipeline sheathing in mining goaf areas, comprising:

[0031] The first connector sheet metal 1 and the second connector sheet metal 2 are hinged at their fixed ends by a hinge 4.

[0032] Fixed shafts 5 are respectively provided along the width direction of the free ends of the first connector sheet metal 1 and the second connector sheet metal 2; the two fixed shafts 5 of the first connector sheet metal 1 and the second connector sheet metal 2 are locked by fastening bolts 6 to form a cylindrical clamp structure that can be repeatedly opened and closed.

[0033] The nitrile rubber sealing gasket 3 is set along the inner arc direction of the cylindrical clamp structure of the first connector sheet metal 1 and the second connector sheet metal 2, and the two ends of the nitrile rubber sealing gasket 3 extend from the free ends of the first connector sheet metal 1 and the second connector sheet metal 2 respectively.

[0034] I. Structural Composition

[0035] First connector sheet metal 1 and second connector sheet metal 2

[0036] Both are semi-circular metal sheet metal parts set on the same axis of rotation, integrally cast from ductile iron, with a wall thickness of 5mm to 8mm, and the inner diameter is clearance-fitted with the outer diameter of the mining pipeline sheath; the fixed end of each sheet metal is machined with a rectangular notch along the generatrix direction for inserting the double blades of the hinge 4, with an insertion depth of ≥10mm, and is permanently fixed by interference fit and saddle screws; the free end extends outward along the width direction to form a flange, and a through circular hole is opened in the center of the flange for inserting the fixed shaft 5.

[0037] Hinge 4

[0038] The double-blade metal hinge has a blade thickness of 4mm and a shaft diameter of 6mm. Both ends of the shaft are riveted to prevent detachment. The hinge has a closing limit angle of 180° and an opening limit angle of approximately 270°, ensuring that the clamp can be fully opened to separate the two semicircles, making it easy to insert the pipe.

[0039] Fixed shaft 5

[0040] The cylindrical carbon steel shaft has a diameter that transitions to the flange hole. Radial pin holes are machined at both ends to insert cotter pins and prevent axial movement. Two to four sets of threaded blind holes with M10 thread and a depth of 15 mm are opened along the generatrix in the middle section of the shaft to receive fastening bolts 6.

[0041] Fastening bolts 6

[0042] High-strength hexagonal flange bolts, performance grade 8.8, specification M10×35mm; the bolt centerline is parallel to the axis of the cylindrical clamp, and the head is recessed into the countersunk hole of the ductile iron flange. The depth of the countersunk hole is equal to the height of the bolt head to ensure that there is no protrusion on the outer contour and to avoid bumping; tightening torque 80N·m~100N·m.

[0043] Nitrile rubber sealing gasket 3

[0044] The annular flat gasket is 2mm to 3mm thick, with a Shore A hardness of 65°±5°, a temperature resistance of -40℃ to +100℃, and is resistant to gas, acids, and alkalis. The outer diameter of the gasket is equal to the inner diameter of the sheet metal, and the inner diameter is 1mm smaller than the outer diameter of the pipeline sheath, forming an initial interference fit. Both ends of the gasket extend 10mm from the free end to form a "long tail," which is pressed by the flange when the clamp is closed, achieving an auxiliary seal on the end face.

[0045] Docking and positioning stop

[0046] The free end face is machined with a 3mm×3mm concave-convex step. The boss is located on the first connector sheet metal, and the groove is located on the second connector sheet metal. When closed, the boss is embedded in the groove to achieve circumferential positioning and resist shearing misalignment.

[0047] II. Dynamic Working Process

[0048] Step 1 Initial Startup State

[0049] The operator can loosen all the fastening bolts by one hand, about 6 turns, with the bolt heads still in the countersunk holes to prevent loss; rotate the second connector sheet metal 2 outward with the hinge 4 pivot as the center, the clamp opening angle is ≥180°, and the pipeline sheath can be moved in or out laterally without axial movement space.

[0050] Step 2 Pre-positioning closure

[0051] Place the pipeline sheath in the semi-circular groove of the first connector sheet metal 1, and the inner arc surface of the nitrile rubber sealing gasket 3 is in contact with the outer wall of the sheath; pull back the second connector sheet metal 2, and the concave and convex stepped stop automatically guides the two sheet metal pieces to center until the free end flanges are in contact with each other. At this time, the "long tail" of the sealing gasket is pre-compressed by 1mm.

[0052] Step 3: Tighten and lock

[0053] Tighten the 6 fastening bolts in sequence, increasing the torque from 0 to 80 N·m; reduce the flange spacing, increase the gasket compression from 1 mm to 2 mm, achieving a 30% compression rate; simultaneously compress the plastic-elastic composite sealing ring, compressing the EPDM ring diameter from 2 mm to 1.4 mm, and expanding the PTFE ring outward by 0.2 mm, tightly adhering to the sheet metal groove wall, forming an initial sealing pressure ≥0.8 MPa.

[0054] Step 4: Dynamic Deformation Response During Service

[0055] The movement of rock strata in the goaf causes axial expansion and contraction of the pipeline by ±35mm and radial deflection by ±15°; the clamps follow the movement.

[0056] a. Axial displacement is absorbed by the gap between the ductile iron and the sheath (1mm on one side) and the sliding interface of the sealing gasket. The friction coefficient between the sealing gasket and the sheath is ≤0.3, and the sliding resistance is <200N, thus avoiding wear on the pipeline surface.

[0057] b. Radial deflection is compensated by the slight rotation of the hinge at 4 degrees and the elastic shear deformation of the gasket. The maximum shear strain of the gasket is 15%, which is far lower than its elongation at break of 300%.

[0058] c. When the external pressure suddenly increases from 0.6MPa to 2.4MPa due to gas explosion or water impact, the EPDM ring expands radially, pushing the PTFE ring to adhere tightly to the outer wall of the sheath, and the sealing pressure increases synchronously to 2.0MPa, achieving a self-reinforcing effect of "the more pressure, the tighter it gets", with no leakage after 30 bar pressure holding for 30 minutes.

[0059] Step 5: Inspection and Disassembly

[0060] When it is necessary to replace the seal or move the pipe, loosen the fastening bolt 6 turns in the opposite direction, open it to 180°, and the sealing gasket and composite sealing ring will separate with the sheet metal and can be removed as a whole for inspection; the entire disassembly and assembly process can be completed by one person in 3 minutes without any power tools or open flame operations.

[0061] In some specific embodiments, both the first connector sheet metal 1 and the second connector sheet metal 2 are semi-circular arc-shaped sheet metal integrally cast from ductile iron, with a wall thickness of 5-8mm and an inner diameter that is clearance-fitted with the outer diameter of the mining pipeline sheath.

[0062] In some specific embodiments, the hinge 4 has a double-blade structure, with the blades respectively embedded into the fixed ends of the first connector sheet metal 1 and the second connector sheet metal 2, with an embedding depth of not less than 10mm.

[0063] In some specific embodiments, 2 to 4 sets of fastening bolts 6 are evenly distributed along the edge of the free end of the connector sheet metal, the center line of the bolts is parallel to the axis of the cylindrical clamp, and the bolt head is sunk into the countersunk hole of the ductile iron bearing flange.

[0064] In some specific embodiments, the nitrile rubber sealing gasket 3 is an annular flat gasket with a thickness of 2-3 mm.

[0065] In some specific embodiments, the free end faces of the first connector sheet metal 1 and the second connector sheet metal 2 are provided with a mating positioning stop, which is a 3mm×3mm concave-convex step for circumferential positioning and to prevent misalignment and shearing.

[0066] In some specific embodiments, the fixed shaft 5 has bolt holes along its length for connection with fastening bolts 6.

[0067] In some specific embodiments, the device has a symmetrical two-half structure. No special tools are required for installation. The connection or disassembly of the pipeline sheath can be completed within 3 minutes simply by tightening or loosening the bolts 6.

[0068] The working principle of this utility model is based on four coupling mechanisms: self-clamping, sealing, pressure self-reinforcing, and dynamic follow-up, to achieve reliable sealing and rapid maintenance of pipeline sheaths in coal mine goaf areas under continuous deformation conditions. The specific principle is as follows:

[0069] self-clamping principle of clamp

[0070] The two halves of the ductile iron sheet metal are hinged to form a rotating pair, with the free end flange and the fixed shaft forming a closed force loop. When the fastening bolts are pre-tightened, the flange spacing decreases, generating radial contraction force, causing the inner diameter of the clamp to shrink uniformly by 1mm to 2mm. The nitrile rubber gasket is compressed by 30%, forming an initial elastic sealing pressure. At the same time, the high rigidity of the ductile iron ensures that the contraction force does not decrease, avoiding the sealing degradation caused by bolt loosening in traditional flanges.

[0071] Sealing principle

[0072] The nitrile rubber sealing gasket is interference-fitted with the outer wall of the pipeline sheath, and a surface contact seal is generated under the radial force of the clamp, blocking the axial seepage path of gas and water along the pipe wall;

[0073] Dynamic follow-up principle

[0074] A 1mm gap is reserved between the clamp and the pipeline on both sides. The hinge allows for 0° to 15° deflection. The nitrile rubber gasket can generate ≤15% elastic deformation in the shear direction. When the pipeline undergoes axial expansion and contraction of ±35 mm or radial deflection of ±15° due to rock movement, the clamp can slide coaxially with the pipeline or rotate at a slight angle. The sliding interface of the gasket maintains constant contact stress, avoiding stress concentration and fatigue cracks. At the same time, the sliding resistance is <200N, which does not increase the additional load on the pipeline and eliminates weld tearing or bolt shearing caused by forced constraints in traditional welding or flange connections.

[0075] Quick disassembly and assembly principle

[0076] The hinge pre-positioning allows the two halves of the sheet metal to open at an angle of ≥180°, forming a "side-open" working space; installation or disassembly can be completed by tightening or loosening only 2 to 4 fastening bolts, without the need for axial movement of pipelines, welding or power tools, which complies with the "no fire" regulations in coal mines; the sealing gasket and composite sealing ring can be fully exposed as the clamp opens, enabling visual inspection and plug-and-play replacement, reducing maintenance time from the traditional 2 hours to 3 minutes.

[0077] Through the synergistic effect of the above principles, this utility model achieves comprehensive performance of zero leakage at 30 bar, maintenance-free operation for 24 months, and rapid replacement in a coupled environment of continuous deformation, high-pressure gas, and water impact in goaf areas, completely solving the problems of sealing failure, insufficient compensation, and difficult maintenance of traditional flange, sleeve, and welding methods.

[0078] By adopting the above-disclosed technical solution of this utility model, the following beneficial effects are obtained:

[0079] After the clamp is tightened, no air bubbles escape after holding at 30 bar water or gas pressure for 30 minutes, reducing the probability of seal failure to zero. When the pipeline axially expands by ±35mm or radially deflects by ±15°, the clamp slides accordingly without pull-out, twisting, or fatigue cracks, maintaining its initial sealing pressure even after one year of continuous operation. Disassembly and assembly require only loosening 2-4 bolts, which can be completed by one person in 3 minutes, reducing maintenance downtime to 1 / 40th of traditional methods. The entire system has passed ExdIMb explosion-proof certification, allowing direct live-line work in environments with gas concentrations of 0-100%, eliminating the risk of hot work. The component lifespan is extended from 6 months to 24 months, reducing replacements by 3 times throughout its lifespan and saving 70% on material and labor costs; the device weighs less than 3kg, reducing the labor intensity of underground handling by 50%; due to reliable sealing, gas leakage is eliminated, and the methane concentration in adjacent working faces decreases by 0.2% to 0.4%, with ventilation energy consumption decreasing simultaneously; the goaf bundle tubes and temperature measuring optical cables require no secondary maintenance after one-time installation, ensuring continuous mining progress and increasing annual output by 12,000 tons per mine; the symmetrical structure allows for reverse reuse, and after decommissioning, it is 100% recyclable and remanufactured, with no solid waste emissions.

[0080] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A special connecting device for pipeline sheathing in mining goaf areas, characterized in that, include: The first connector sheet metal (1) and the second connector sheet metal (2) are hinged at their fixed ends by a hinge (4); Fixed shafts (5) are respectively provided along the width direction of the free ends of the first connector sheet metal (1) and the second connector sheet metal (2); the two fixed shafts (5) of the first connector sheet metal (1) and the second connector sheet metal (2) are locked by fastening bolts (6) to form a cylindrical clamp structure that can be repeatedly opened and closed; The nitrile rubber sealing gasket (3) is arranged along the inner arc direction of the cylindrical clamp structure of the first connector sheet metal (1) and the second connector sheet metal (2). The two ends of the nitrile rubber sealing gasket (3) extend from the free ends of the first connector sheet metal (1) and the second connector sheet metal (2), respectively.

2. The connecting device according to claim 1, characterized in that: Both the first connector sheet metal (1) and the second connector sheet metal (2) are semi-circular arc-shaped sheet metal integrally cast from ductile iron, with a wall thickness of 5-8 mm and an inner diameter that is clearance-fitted with the outer diameter of the mining pipeline sheath.

3. The connecting device according to claim 1, characterized in that: The hinge (4) is a double-blade structure, with the blades respectively embedded into the fixed ends of the first connector sheet metal (1) and the second connector sheet metal (2), with an embedding depth of not less than 10mm.

4. The connecting device according to claim 1, characterized in that: The fastening bolts (6) are evenly distributed in 2 to 4 groups along the edge of the free end of the connector sheet metal. The center line of the bolts is parallel to the axis of the cylindrical clamp, and the bolt head is sunk into the countersunk hole of the ductile iron bearing flange.

5. The connecting device according to claim 1, characterized in that: The nitrile rubber sealing gasket (3) is an annular flat gasket with a thickness of 2-3 mm.

6. The connecting device according to claim 1, characterized in that: The free end faces of the first connector sheet metal (1) and the second connector sheet metal (2) are provided with a butt positioning stop. The stop is a 3mm×3mm concave-convex step, which is used for circumferential positioning and to prevent misalignment and shearing.

7. The connecting device according to claim 1, characterized in that: The fixed shaft (5) has bolt holes along its length for connecting with fastening bolts (6).

8. The connecting device according to any one of claims 1 to 7, characterized in that: The device has a symmetrical two-half structure.

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