A special protection device for mine goaf pipeline

Abstract

The utility model discloses a kind of special protection devices for mined-out area pipeline, belong to coal mine safety monitoring supporting equipment.The device is closed annular by the inner steel ring (1) and outer steel ring (2) of coaxial sleeve by connecting piece (3) spiral locking, two ends are gradually expanded by four-stage steel ring variable diameter structure (4,5,6,7) gradually expanding, form the expansion cavity that can accommodate beam tube dust filter;Conical surface friction pair (8) of inner and outer steel ring alternately superimposed can slide relatively under axial load, 60-70% impact energy is converted into friction heat and dissipates, hysteresis characteristic is generated due to friction drag when unloading, avoid rebound damage;Single ring damage can be independently replaced, maintenance is convenient.The device as a whole is formed by 65Mn steel rolling and heat treated, with the advantages of light weight, corrosion resistance, impact resistance and convenient underground rapid laying, can long-term protect the integrity of beam tube monitoring and fiber temperature measurement system pipeline in mined-out area, significantly improve coal mine safety production guarantee capability.

Description

Technical Field

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

[0002] The goaf formed after coal mining is often accompanied by roof collapse, rock strata displacement and rock burst. The bundled tubes for monitoring and the distributed optical fiber temperature measurement cables arranged in this area are very easy to be cut, pulled apart or bent excessively, resulting in interruption of monitoring data and posing a major hidden danger to safe production.

[0003] Existing technologies generally employ rigid protection by laying steel pipes or channel steel throughout the entire process, which has the following shortcomings:

[0004] The large quantity of steel pipes used results in high material and installation costs.

[0005] Steel pipe joints require welding or flange connections, and hot work operations underground are risky and inefficient.

[0006] Rigid pipes cannot absorb impact energy and are easily crushed in one go when the top plate suddenly presses down, thus losing their protective ability.

[0007] Repair and replacement are difficult; once a part is damaged, the entire section needs to be removed, resulting in long maintenance cycles and high costs.

[0008] Therefore, there is an urgent need for a flexible protection device that is low-cost, easy to install, reusable, and can effectively absorb impact energy to solve the above problems. Utility Model Content

[0009] The purpose of this utility model is to provide a special protection device for pipelines in mining goaf areas, thereby solving the aforementioned problems existing in the prior art.

[0010] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0011] A special protection device for pipelines in mining goaf areas includes:

[0012] The inner steel ring and the outer steel ring are coaxially sleeved and alternately stacked along the axial direction to form a conical friction pair that can slide relative to each other.

[0013] The connector includes a tension spring and a connecting spring; the tension spring and the connecting spring have the same pitch and direction of rotation and are helically connected by rotational force to form a closed ring, which elastically locks the inner steel ring and the outer steel ring in the circumferential direction.

[0014] The four-section steel ring variable diameter structure is arranged sequentially along the axial direction. The variable diameter structure is a concentric double spring structure with the outer spring diameter increasing in each section. The outer spring diameter increases by 5mm in each section, and the inner and outer springs rotate in opposite directions. This is used to form an expansion space at the top of the device to accommodate the bundle tube dust filter.

[0015] The inner steel ring, outer steel ring and variable diameter structure are all made of 65Mn steel, rolled and heat treated, with a surface hardness ≥45HRC;

[0016] The device is ring-shaped with a height of 5000mm and a single ring cross-section of 50mm×50mm. It can dissipate energy through relative sliding of the conical friction pair under axial load. During unloading, it has a hysteresis characteristic due to frictional resistance, and the energy absorption rate is 60-70%.

[0017] In some specific embodiments, the tension spring of the connector and the connecting spring are screwed together by an M6 thread with a screw length ≥20mm, ensuring connection strength and enabling independent replacement after single ring damage.

[0018] In some specific embodiments, the inner diameter of the inner steel ring is 2-4 mm larger than the outer diameter of the bundle tube or the temperature measuring optical cable, so as to allow for insertion and leave a gap for thermal expansion and contraction.

[0019] In some specific embodiments, the cone angle of the conical friction pair is 15° and the surface roughness Ra≤3.2μm, so as to stably provide hysteresis characteristics and energy absorption rate.

[0020] In some specific embodiments, the total free height of the concentric double springs in the four-section steel ring variable diameter structure is 300mm, and the pitch is 20mm. It can achieve four-stage diameter expansion without increasing the overall length, with the maximum outer diameter increasing to Φ110mm, which meets the dust filter installation space requirements.

[0021] The outer diameters of the four-section steel ring variable diameter structure are 55mm, 60mm, 65mm, and 70mm respectively.

[0022] The beneficial effects of this utility model are:

[0023] Significant energy absorption: Through the relative sliding of the inner and outer ring conical friction pairs, axial impact energy is converted into frictional heat. The measured energy absorption rate can reach 60-70%, which is much higher than that of ordinary rigid steel pipes, significantly reducing the peak tensile force and bending risk of bundle tubes / optical cables.

[0024] Material and cost savings: The steel consumption of the ring structure is only 35-45% of that of steel pipes of the same length. It eliminates the need for welding, flanges, and a large number of supports and hangers, reducing on-site installation time by more than 50% and reducing overall costs by about 40%.

[0025] Easy maintenance: The segmented spiral connection allows for individual disassembly and replacement of any damaged steel ring or spring without having to remove the entire pipeline, reducing downtime for maintenance.

[0026] Expanded diameter integration: The four-stage variable diameter structure forms a Φ70mm expanded cavity at the top of the device, which can directly accommodate the bundle tube dust filter, reduce additional transition joints, and simplify system layout.

[0027] Strong environmental adaptability: After heat treatment, the surface hardness of 65Mn steel is ≥45HRC, which is wear-resistant and corrosion-resistant. It can be used continuously for more than 5 years in humid, sulfur-containing and weakly alkaline mine water; the ring flexible structure allows a bending radius ≤1m, which can adapt to the undulation of the goaf floor and the bends of the roadway.

[0028] Enhanced safety and reliability: The device's failure mode is "controllable progressive slip," which prevents secondary impacts caused by sudden fractures of steel pipes; its hysteresis rebound characteristics can also reduce the impact on fixed anchor points, extend anchoring life, and provide long-term, stable, and reliable physical protection for monitoring the "three belts" in coal mine goaf areas. Attached Figure Description

[0029] Figure 1 This utility model relates to a special protection device for pipelines in mining goaf areas.

[0030] In the attached diagram, 1 is the inner steel ring; 2 is the outer steel ring; 3 is the connecting piece; 4 is the first section steel ring diameter changing structure; 5 is the second section steel ring diameter changing structure; 6 is the third section steel ring diameter changing structure; 7 is the fourth section steel ring diameter changing structure; and 8 is the conical friction pair. Detailed Implementation

[0031] 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.

[0032] Reference Figure 1 The illustrated protective device for pipelines in mining goaf areas includes:

[0033] Inner steel ring 1 and outer steel ring 2 are coaxially sleeved and alternately stacked along the axial direction to form a relatively sliding conical friction pair 8).

[0034] The connecting component 3 includes a tension spring and a connecting spring; the tension spring and the connecting spring have the same pitch and direction of rotation and are helically connected by rotational force to form a closed ring, which elastically locks the inner steel ring 1 and the outer steel ring 2 in the circumferential direction.

[0035] The four steel ring diameter-changing structures 4, 5, 6 and 7 are arranged sequentially along the axial direction. The diameter-changing structure is a concentric double spring structure with the outer spring diameter increasing in each section. The outer spring diameter increases by 5mm in each section, and the inner and outer springs rotate in opposite directions. This is used to form an expansion space at the top of the device to accommodate the bundle tube dust filter.

[0036] The inner steel ring 1, outer steel ring 2, and four-section steel ring variable diameter structures 4, 5, 6, and 7 are all made of 65Mn steel, rolled and heat-treated, with a surface hardness ≥45HRC.

[0037] The device is ring-shaped with a height of 5000mm and a single ring cross-section of 50mm×50mm. It can dissipate energy through relative sliding of the conical friction pair 8 under axial load. During unloading, it forms a hysteresis characteristic due to frictional resistance, with an energy absorption rate of 60-70%.

[0038] In some specific embodiments, the tension spring of connector 3 and the connecting spring are screwed together by M6 thread, with a screw length ≥20mm, to ensure connection strength and enable independent replacement after single ring damage.

[0039] In some specific embodiments, the inner diameter of the inner steel ring 1 is 2-4 mm larger than the outer diameter of the bundle tube or the temperature measuring optical cable, so as to allow for insertion and leave a gap for thermal expansion and contraction.

[0040] In some specific embodiments, the cone angle of the conical friction pair 8 is 15° and the surface roughness Ra≤3.2μm, so as to stably provide hysteresis characteristics and energy absorption rate.

[0041] In some specific embodiments, the total free height of the concentric double springs of the variable diameter structures 4, 5, 6, and 7 is 300mm, with a pitch of 20mm. This allows for four-stage diameter expansion without increasing the overall length, with the maximum outer diameter increasing to Φ110mm, thus meeting the dust filter installation space requirements.

[0042] In some specific embodiments, the outer diameters of the four-section steel ring variable diameter structure 4, 5, 6, and 7 are respectively: 55mm; 60mm; 65mm; and 70mm.

[0043] This utility model discloses a special protection device for pipelines in mining goaf areas. The device is a closed ring structure with a height of 5000 mm and a single-ring cross-section of 50 mm × 50 mm, coaxially sleeved on the outside of a bundled tube or distributed optical fiber temperature measurement cable. The device consists of the following parts:

[0044] Inner steel ring 1 and outer steel ring 2

[0045] Both components are made of 65Mn steel, rolled and heat-treated to a surface hardness ≥45HRC, and alternately stacked along the axial direction to form a pair of conical friction pairs with a cone angle of 15° and a surface roughness Ra≤3.2μm. In the initial state, the friction pair is in static friction lock, providing radial support and axial stiffness for the cable.

[0046] Connector 3

[0047] It consists of a tension spring and a connecting spring. The two springs have the same pitch and direction of rotation. They are screwed together by rotational force to form a closed ring. The inner and outer steel rings are elastically locked in the circumferential direction by means of M6 thread engagement length ≥20mm. When a single ring is damaged, it can be quickly disassembled by rotating in the opposite direction and can be replaced independently.

[0048] The first to fourth steel ring diameter changing structures 4, 5, 6, and 7

[0049] All four sections are designed with concentric double springs. The outer spring diameter increases by 5mm from bottom to top, corresponding to outer diameters of 55mm, 60mm, 65mm, and 70mm respectively. The inner and outer springs rotate in opposite directions, with a total free height of 300mm and a pitch of 20mm. This design, without increasing the overall length, creates an enlarged cavity with a maximum outer diameter of Φ110mm at the top of the device, which can directly accommodate and position the bundled tube dust filter, eliminating the need for additional transition joints.

[0050] [Dynamic Work Process]

[0051] resting phase

[0052] After the device is fitted onto the cable, the inner hole of the inner steel ring 1 maintains a gap of 2-4mm with the outer diameter of the cable to compensate for thermal expansion and contraction; the connector 3 provides initial pre-tightening force, so that the conical friction pair 8 is in static friction balance, and the whole is in a slightly tensioned flexible suspension state.

[0053] Impact loading stage

[0054] When the roof of the goaf suddenly presses down or the rock strata shift, generating axial impact loads, the outer steel ring 2 slips controllably relative to the inner steel ring 1 along a 15° conical surface. Static friction is converted into dynamic friction, and the impact kinetic energy is rapidly converted into frictional heat and dissipated. At the same time, the tension spring and the connecting spring extend together, storing elastic potential energy and forming the first stage of energy buffering. Actual measurements show that this stage can absorb 60-70% of the incident energy, significantly reducing the peak tension and bending risk of the cable.

[0055] Delayed unloading phase

[0056] After the load is removed, the tension spring and the connecting spring begin to retract. However, due to the resistance of the conical friction pair 8, the reset speed of the inner and outer steel rings is much slower than the spring rebound speed, resulting in obvious mechanical hysteresis characteristics. This effectively suppresses the secondary impact on the cable caused by the instantaneous rebound, while reducing the reverse impact on the anchoring points at both ends and extending the anchoring life.

[0057] Lateral disturbance coupling stage

[0058] If the impact is accompanied by lateral swinging, the concentric double springs of the first to fourth steel ring diameter-changing structures 4, 5, 6, and 7 will twist and restrain each other due to opposite rotation directions, forming additional torsional damping and further absorbing lateral energy. The four-stage outer diameter-gradient structure avoids stress concentration caused by abrupt changes in cross-section, ensuring that the device maintains overall continuity and flexibility under complex dynamic loads.

[0059] Failure and Replacement Phase

[0060] When a steel ring or spring experiences fatigue fracture or plastic deformation, the M6 ​​threaded interface of connector 3 can be quickly unscrewed in the reverse direction, enabling independent removal and replacement of a single ring without having to remove the entire cable. This reduces maintenance time from several hours in the traditional steel pipe solution to tens of minutes, significantly reducing downtime for maintenance losses.

[0061] Through the above continuous and reversible energy dissipation and hysteresis reset mechanism, this utility model provides long-term, stable and reliable physical protection for coal mine goaf bundle tube monitoring and fiber optic temperature measurement systems while maintaining the advantages of lightweight, corrosion resistance and easy maintenance.

[0062] By adopting the above-disclosed technical solution of this utility model, the following beneficial effects are obtained:

[0063] Energy absorption rate significantly improved

[0064] By utilizing the controllable sliding of the 15° conical friction pair (8) of inner and outer steel rings, 60-70% of the axial impact kinetic energy is converted into frictional heat dissipation, which is much higher than the almost zero absorption of ordinary rigid steel pipes. This significantly reduces the peak tension and bending risk of bundle tubes / optical cables, ensuring continuous and reliable monitoring data.

[0065] Material and construction costs decreased simultaneously

[0066] The steel consumption of the ring structure is only 35-45% of that of steel pipes of the same length. It eliminates the need for welding, flanges, and a large number of supports and hangers, reducing on-site installation time by more than 50% and reducing overall costs by about 40%, significantly reducing the transportation of materials and labor intensity in the mine.

[0067] Easy maintenance and minimal downtime losses

[0068] The segmented spiral connection design allows any damaged steel ring or spring to be replaced independently without having to remove the entire pipeline, reducing maintenance time from several hours to tens of minutes and minimizing production losses caused by downtime for maintenance.

[0069] Improved system integration

[0070] The first to fourth steel ring diameter-changing structures directly form a Φ70mm enlarged cavity at the top of the device, which can accommodate the bundled tube dust filter in one piece, eliminating the need for additional transition joints, simplifying system layout, and reducing the number of leakage points.

[0071] Environmental adaptability and lifespan extension

[0072] After heat treatment, 65Mn steel has a surface hardness of ≥45HRC, is wear-resistant and corrosion-resistant, and can be used continuously for more than 5 years in humid, sulfur-containing and weakly alkaline mine water; the flexible ring structure allows a bending radius of ≤1m, easily adapting to the undulation of the goaf floor and the bends of the roadway.

[0073] Failure Mode

[0074] The device failure manifests as "controllable progressive slippage," preventing secondary impacts caused by sudden fractures of steel pipes; the hysteresis rebound characteristic reduces the impact on anchor points, extends the life of anchor bolts, and provides long-term, stable, and reliable physical protection for monitoring the "three belts" in coal mine goaf areas.

[0075] 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 protection device for pipelines in mining goaf areas, characterized in that, include: The inner steel ring (1) and the outer steel ring (2) are coaxially sleeved and stacked alternately along the axial direction to form a relatively sliding conical friction pair (8). The connector (3) includes a tension spring and a connecting spring; the tension spring and the connecting spring have the same pitch and direction of rotation and are connected by a rotary force to form a closed ring, which elastically locks the inner steel ring (1) and the outer steel ring (2) in the circumferential direction. The four steel ring diameter-changing structures (4, 5, 6, 7) are arranged sequentially along the axial direction. The diameter-changing structure is a concentric double spring structure with the outer spring diameter increasing in each section. The outer spring diameter increases by 5mm in each section, and the inner and outer springs rotate in opposite directions. This structure is used to form an expansion space at the top of the device to accommodate the bundle tube dust filter. The inner steel ring (1), outer steel ring (2) and four-section steel ring variable diameter structure (4, 5, 6, 7) are all made of 65Mn steel, rolled and heat treated, with a surface hardness ≥45HRC; The device is ring-shaped with a height of 5000mm and a single ring cross-section of 50mm×50mm. It can consume energy through relative sliding of the conical friction pair (8) under axial load. When unloading, it forms a hysteresis characteristic due to frictional resistance, and the energy absorption rate is 60-70%.

2. The protection device according to claim 1, characterized in that: The tension spring and the connecting spring of the connector (3) are screwed together by an M6 thread, with a screw length ≥20mm, to ensure connection strength and enable independent replacement after single ring damage.

3. The protection device according to claim 2, characterized in that: The inner diameter of the inner steel ring (1) is 2-4 mm larger than the outer diameter of the bundle tube or the temperature measuring optical cable, so as to allow for insertion and leave a gap for thermal expansion and contraction.

4. The protection device according to claim 3, characterized in that: The cone angle of the conical friction pair (8) is 15° and the surface roughness Ra≤3.2μm, so as to stably provide the hysteresis characteristics and energy absorption rate.

5. The protective device according to any one of claims 1-4, characterized in that: The total free height of the concentric double springs in the variable diameter structure (4, 5, 6, 7) is 300mm, and the pitch is 20mm. It can achieve four-stage diameter expansion without increasing the overall length, with the maximum outer diameter increasing to Φ110mm, which meets the installation space requirements of the dust filter.

6. The protection device according to claim 1, characterized in that: The outer diameters of the four-section steel ring variable diameter structure (4, 5, 6, 7) are 55mm, 60mm, 65mm, and 70mm respectively.

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