Installation method of emulsified base vertical conveying system pipeline

Abstract

The invention discloses a method for installing pipelines of an emulsion matrix vertical conveying system, belongs to the technical field of mine underground emulsion explosive conveying, and mainly solves the problems that multiple pipelines in a vertical shaft are easy to deviate and fall and the construction efficiency is low during vertical installation. According to the technical scheme, the method comprises the steps that a pipeline is pre-assembled in a segmented mode, disc elevators are installed, the pipeline is installed in a wall protection sleeve with multiple sets of one-way limiting structures on the inner side, and the multiple disc elevators are connected in series through steel wire ropes; after the whole pipeline is put down to a vertical shaft, concrete is poured to fix the wall protection sleeve, and safe, controllable and efficient vertical installation of the pipeline is achieved in the mode that a one-way limiting structure rotates the bearing disc elevator clockwise when the pipeline is put down and rotates anticlockwise to release the pipeline when the pipeline is lifted up. The method is mainly used for quickly and stably laying the emulsion matrix, the sensitizer and the communication pipeline in a mine underground emulsion explosive production system.

Description

Technical Field

[0001] This invention relates to the field of underground emulsion explosives delivery technology in mines. More specifically, this invention relates to a method for installing a pipeline in a vertical delivery system for emulsion matrix. Background Technology

[0002] The installation of emulsion matrix vertical delivery system pipelines within shafts is a crucial step in underground emulsion explosives production technology in mines. Existing installation methods typically face several long-standing technical challenges.

[0003] First, the considerable depth of the shaft makes the pipes prone to shifting or falling under their own weight, making positioning and fall prevention during installation difficult. Previous methods of segmented hoisting and reconnection were not only inefficient but also posed safety hazards due to difficulties in ensuring concentricity during pipe connection. This is because the limited working space within the shaft, the lack of reliable intermediate supports and fall prevention structures, and the difficulty in achieving effective two-way control during pipe lowering are all contributing factors.

[0004] Secondly, vertical delivery systems for emulsion matrices typically consist of multiple pipelines with different functions, such as pipelines for delivering the emulsion matrix, pipelines for delivering sensitizers, and communication pipelines. These pipelines need to maintain their relative positions and be installed as a whole, synchronously. Existing methods often employ separate installation or temporary bundling, which makes it difficult to guarantee the integrity and stability of the multi-pipeline system. After installation, problems such as interference between pipelines or collisions with the wellbore can easily occur. This is because there is a lack of a dedicated fixing structure that can reliably clamp multiple pipelines and lower them together.

[0005] Third, under deep well installation conditions, there is a lack of clear design guidelines for determining the dimensional matching and safety distances between pipes, fasteners, and the wall structure. Mechanical interference is prone to occur during installation, such as pipe jamming or scraping of the inner wall, affecting construction safety and efficiency. Furthermore, the setting of hoisting spacing relies heavily on experience, failing to systematically consider the wire rope's load-bearing capacity, elongation, and safety under unexpected single-rope conditions, making it difficult to achieve reliable control of the hoisting process while ensuring economic efficiency. These problems stem from the lack of a comprehensive design standard integrating mechanical design, structural mechanics, and installation technology in this field, resulting in insufficient assurance of installation quality and construction safety.

[0006] Therefore, an installation method is needed to solve the above problems and achieve efficient, safe and reliable installation of emulsion matrix vertical delivery system pipelines in vertical shafts. Summary of the Invention

[0007] One objective of this invention is to provide an installation method for a vertical conveying system pipeline of an emulsion matrix. This method is mainly used for the rapid and stable laying of emulsion matrix, sensitizer, and communication pipelines in underground emulsion explosives production systems in mines.

[0008] To achieve these objectives and other advantages of the present invention, according to one aspect of the present invention, a method for installing a pipeline in a vertical delivery system for an emulsion matrix is ​​provided, comprising the following steps: Step 1: Pre-assemble the vertical delivery system pipeline of the emulsion matrix into multiple single-section pipelines, and install disc hangers on the outer periphery of each single-section pipeline; Step 2: Install the pre-assembled vertical delivery system pipeline with disc hangers into a protective sleeve, and install multiple sets of one-way limiting structures corresponding to the disc hangers at intervals along the axial direction on the inner side wall of the protective sleeve. Then, pass through and connect multiple disc hangers in sequence with two steel wire ropes. Step 3: Lower the protective sleeve obtained in Step 2, along with the pre-assembled emulsified matrix vertical delivery system pipeline with disc hanger, into the shaft, and pour concrete into the annular space between the protective sleeve and the shaft wall to fix it. When the disc hanger moves downward along the protective sleeve of the vertical conveying system pipeline of the emulsion matrix, it pushes the one-way limiting structure to rotate clockwise to the limiting state, supporting the corresponding disc hanger. As the disc hanger moves upward along the protective sleeve of the vertical delivery system pipeline for the emulsion matrix, it pushes the one-way limiting structure to rotate counterclockwise to the open state, allowing the disc hanger to pass through.

[0009] Preferably, each set of unidirectional limiting structures includes two symmetrical unidirectional limiting components. Each unidirectional limiting component is provided with a bracket fixed to the inner wall of the protective sleeve and a limiting plate hinged to the bracket by a pin. The limiting plate is a triangular prism structure, and the pin is hinged to the right-angle edge of the limiting plate.

[0010] Preferably, the emulsion matrix vertical delivery system pipeline includes an emulsion matrix delivery pipeline, a sensitizer delivery pipeline, and a communication pipeline that are parallel to each other. The disc hanger is formed by two semi-cylindrical hanger assemblies that are fixed together by fastening bolts, and the opposite sidewalls of the two hanger assemblies are provided with arc-shaped grooves that match the emulsion matrix delivery pipeline, the sensitizer delivery pipeline, and the communication pipeline.

[0011] Preferably, the dimensions of the protective sleeve and the disc hanger are determined according to the following method: Outer diameter D of the protective sleeve s With shaft diameter D h Well wall design clearance c h Satisfying: Ds≤D h -2c h Inner diameter d of the protective sleeve s With wall thickness t s Satisfy: d s =D s-2t s ; The outer diameter D of the disc hanger d The interference prevention conditions of the limit plate must be met simultaneously in both the closed and open states: In the closed state, the following condition is satisfied: D d ≤d s -2(e p +c d ); When enabled, the following condition is met: D d ≤d s -2(e p ×cosβ open +c d ); Among them, e p c represents the radial protrusion of the unidirectional limiting component as a whole. d For the installation gap, β open The opening angle of the limit plate; The radius R of the center hole of the disc hanger h It must be greater than the minimum envelope radius R of the three pipes: the emulsion matrix delivery pipe, the sensitizer delivery pipe, and the communication pipe. bundle Installation gap c d The sum, i.e., R h ≥R bundle +c d This is to ensure that the three tubes can pass through smoothly and maintain the gap.

[0012] Preferably, the minimum envelope radius R of the three pipes—the emulsion matrix delivery pipe, the sensitizer delivery pipe, and the communication pipe—is [not specified]. bundle satisfy: ; Where, r m r is the radius of the emulsion matrix delivery pipe. sen r is the radius of the sensitizer delivery pipeline. c Let g be the radius of the communication channel. pp This refers to the net installation distance between the three pipes.

[0013] Preferably, the minimum net distance g between the outer edge of the emulsion matrix delivery pipe, the sensitizer delivery pipe, and the communication pipe and the inner wall of the protective sleeve is [missing information]. pc Interference prevention conditions must be met: .

[0014] Preferably, the maximum permissible value of the axial pitch s between two adjacent unidirectional limiting structures is s. max The following constraints must be met simultaneously: s max The allowable bearing capacity T between the disc hanger and the one-way limiting structure d,allowThe allowable load-bearing capacity T of the connecting pin pin,allow The total safe bearing capacity T of the two steel wire ropes rope,tot The minimum value among the requirements for wire rope elongation control is determined together with the requirements for wire rope elongation control. Furthermore, the safety verification under single wire rope failure conditions must be met, meaning the single-span load must be less than the allowable bearing capacity T of a single wire rope. rope,1 ,Right now: ; Among them, single span load Δs max EA is the maximum elongation of the wire rope. eff This represents the equivalent axial stiffness of the two steel wire ropes.

[0015] Preferably, the load-bearing capacity T of a single wire rope is... rope,1 Calculated by the following formula: Total safe load capacity T of the two steel wire ropes rope,tot and equivalent axial stiffness EA eff Calculated using the following formulas respectively: , ; Among them, T MBL η is the minimum breaking force of a single wire rope. term For termination efficiency, η b For bending efficiency, η share γ is the load distribution factor. r Where is the safety factor of the wire rope, Er is the elastic modulus of the wire rope, and Ar is the metal cross-sectional area of ​​the wire rope.

[0016] Preferably, the allowable load-bearing capacity T between the disc hanger and the unidirectional limiting structure is... d,allow The smaller value calculated based on the allowable contact stress of the material and the value calculated based on the allowable shear stress is taken, and the calculation formula is as follows: ; where σ c,allow For the allowable contact stress of the material, b p For the contact width, L cont For the effective contact length, τ allow For the allowable shear stress of the material, t d The thickness of the disk; Permissible load capacity T of connecting pin pin,allow The smaller value calculated based on the pin-shaft double shear strength and the value calculated based on the bearing strength is taken, and the calculation formula is as follows: ; where n pin d represents the number of pins. pin τ is the diameter of the pin.allow For the allowable shear stress of the pin material, σ c,allow t is the allowable contact stress of the pin. d The thickness of the stressed component.

[0017] Preferably, the length L of a single pipe section must simultaneously meet the following conditions: ; ; Among them, L hand,min L is the minimum maneuverable pipe length. lift,max H is the maximum pipe length that the lifting equipment can safely lift, H is the total depth of the shaft, and N is the maximum pipe length that the lifting equipment can safely lift. j,max This represents the maximum number of connectors allowed by the system.

[0018] The present invention provides at least the following beneficial effects: The installation method of the emulsion matrix vertical delivery system pipeline of the present invention achieves efficient and safe vertical lowering and precise positioning of the pipeline system by pre-assembling the pipeline in sections and installing disc hangers, then inserting them into a protective sleeve with multiple sets of unidirectional limiting structures, and connecting the hangers in series with steel wire ropes. This effectively prevents the pipeline from shifting or falling during installation. By using symmetrically arranged unidirectional limiting components hinged to the right-angle edges of the triangular prism limiting plate, the structure is ensured to be stable and rotate reliably when supported, effectively bearing the pipeline load and opening smoothly when lifted. The disc hanger, formed by the docking and fixing of two semi-cylindrical hanger components with arc-shaped grooves, can reliably clamp the emulsion matrix delivery pipeline, sensitizer delivery pipeline, and communication pipeline, keeping their relative positions stable during installation and forming a whole for synchronous lowering, avoiding the alignment problems and mutual interference caused by separate installation. By establishing a series of dimensional design guidelines for the casing, shaft, disc clamps, and pipe envelope, the fit relationships and minimum clearance requirements between components were clarified, fundamentally preventing the risk of mechanical jamming or collision with the shaft wall during system operation. By scientifically calculating the maximum permissible axial pitch of adjacent limiting structures and comprehensively considering the load-bearing capacity of the clamps and limiting structures, pin strength, total safe load-bearing capacity of the wire ropes, elongation control, and extreme conditions of single wire rope failure, the lifting spacing was ensured to be both economical and safe, greatly improving the safety of the entire installation process. By specifying the calculation methods for the permissible load-bearing capacity between the disc clamps and limiting structures and the connecting pins, and taking the smaller value as the design basis, the structural strength of key load-bearing components was guaranteed. By comprehensively considering the limits of manual operation, the capacity of lifting equipment, the total depth of the shaft, and the permissible number of joints in the system, the length of a single pipe section was determined, optimizing the pipe segment division. This improved installation efficiency and controlled the number of potential leakage points while ensuring construction safety and feasibility.

[0019] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the installation structure of the protective sleeve, disc hanger, unidirectional limiting structure, and emulsion matrix vertical delivery system pipeline described in one technical solution of the present invention.

[0021] Figure 2 This is a schematic diagram of the installation structure of the disc hanger and the pipeline of the vertical conveying system for emulsified matrix described in one technical solution of the present invention.

[0022] Figure 3 This is a schematic diagram of the structure of the disc-shaped hanging clamp described in one technical solution of the present invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can implement it based on the description.

[0024] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0025] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0026] like Figure 1-3 As shown, the present invention provides a method for installing a pipeline in a vertical delivery system for emulsified matrix, comprising the following steps: Step 1: Pre-assemble the vertical delivery system pipeline 100 into multiple single-section pipelines, and install disc hangers 200 on the outer periphery of each single-section pipeline. Step 2: Install the pre-assembled vertical delivery system pipeline 100 with disc hangers 200 into a protective sleeve 300, and install multiple sets of one-way limiting structures 400 corresponding to the disc hangers 200 at intervals along the axial direction on the inner side wall of the protective sleeve 300. Then, pass through and connect multiple disc hangers 200 in sequence with two steel wire ropes 500. Step 3: Lower the protective sleeve 300 obtained in Step 2, together with the pre-assembled emulsified matrix vertical delivery system pipeline 100 with disc hanger 200, into the vertical shaft, and pour concrete into the annular space between the protective sleeve 300 and the vertical shaft wall to fix it. When the disc hanger 200 moves downward along the protective sleeve 300 with the pipeline 100 of the vertical delivery system for the emulsion matrix, it pushes the one-way limiting structure 400 to rotate clockwise to the limiting state, supporting the corresponding disc hanger 200. When the disc hanger 200 moves upward along the protective sleeve 300 with the emulsion matrix vertical delivery system pipeline 100, it pushes the one-way limiting structure 400 to rotate counterclockwise to the open state, allowing the disc hanger 200 to pass through.

[0027] In the above technical solution, firstly, the vertical delivery system pipeline 100 of the emulsified matrix is ​​pre-assembled into multiple single-section pipelines. Each single-section pipeline can be a seamless steel pipe of standard length, made of Q235B or higher strength structural steel. A disc-shaped lifting clamp 200 is installed around the outer periphery of each single-section pipeline. The disc-shaped lifting clamp 200 can be made of cast steel or forgings, made of ZG270-500 steel. The disc-shaped lifting clamp 200 is fastened to the outer wall of the pipeline with high-strength bolts. The installation position is approximately 500-800mm from the end of the pipeline. This distance can be determined by calculating the pipeline's bending moment and shear force to ensure uniform stress distribution during hoisting.

[0028] Next, the pre-assembled pipe is installed into the protective sleeve 300. The protective sleeve 300 can be a spiral welded pipe, and the material can be Q235B. One-way limiting structures 400 are installed at regular intervals along the axial direction on the inner wall of the protective sleeve 300. The spacing can be determined by calculating the pipe weight and the load-bearing capacity of the wire rope 500, typically 6-12 meters. The one-way limiting structure 400 can be a hinged stop device, the pin material can be 40Cr, and the limiting plate can be Q345 steel plate. Then, two wire ropes 500 are passed through and connected to multiple disc-type lifting clamps 200. The wire ropes 500 can be 6×37+FC type wire ropes 500, and the diameter is determined by calculating the safe load, typically 20-28mm.

[0029] Finally, the assembled system is lowered into the shaft. The lowering speed is controlled at 0.5-1.0 m / s, which can be determined by calculating the system's inertia and braking capacity. Concrete is poured into the annular space between the casing 300 and the shaft wall. C30-C40 strength grade concrete can be used, and the pouring pressure is controlled at 0.3-0.5 MPa. Pressure changes need to be monitored in real time during the pouring process. Pressure values ​​can be collected by a pressure sensor at a sampling frequency of 10 Hz, and continuous monitoring is carried out for 24 hours to ensure that the concrete is fully compacted. The unidirectional limiting structure 400 rotates clockwise to support the lifting clamp when the pipe is lowered and rotates counterclockwise to release it when it is lifted. The rotation angle is controlled by the limiting block, which is usually in the range of 0-90 degrees.

[0030] This method effectively prevents accidental pipeline descent during installation and operation through multiple sets of unidirectional limiting structures 400, improving construction and long-term operational safety. The segmented hoisting combined with flange connections adapts to deep well environments, reducing overall hoisting difficulty and risk. Multiple support points distribute the pipeline's weight and internal fluid load, enhancing system rigidity and vibration resistance. The limiting structures feature unidirectional clearance, facilitating segmented disassembly and replacement during maintenance. When maintenance or replacement of a pipeline segment is required, the pipeline system can be pulled upwards using a winch. During lifting, the disc clamp 200 moves upwards with the pipeline, contacting and pushing the unidirectional limiting structure 400 to rotate counterclockwise to the open state, allowing the clamp to pass smoothly through the limiting point. Once the target pipe segment is lifted to the wellhead operating plane, the flange connection bolts at both ends of the segment can be released, disconnecting and removing it from the system. This process does not require removing the concrete-bonded protective sleeve 300 and does not affect adjacent pipe segments, enabling localized repair and replacement, significantly reducing the difficulty and duration of maintenance operations. The system can quickly adjust parameters such as the casing diameter 300, the clamp spacing, and the wire rope diameter 500 according to the actual well diameter, depth, and working conditions, demonstrating good engineering adaptability.

[0031] In another technical solution, each set of unidirectional limiting structures 400 includes two symmetrical unidirectional limiting members. Each unidirectional limiting member is provided with a bracket 401 fixed to the inner wall of the protective sleeve 300, and a limiting plate 403 hinged to the bracket 401 by a pin 402. The limiting plate 403 is a triangular prism structure, and the pin 402 is hinged to the right angle edge of the limiting plate 403.

[0032] In the above technical solution, each set of unidirectional limiting structures 400 uses two symmetrically arranged unidirectional limiting components. The unidirectional limiting components can be standard industrial limiter assemblies, and their brackets 401 can be semi-cylindrical or cylindrical wedge-shaped structures. Their curved sidewalls match and fit the inner wall of the protective sleeve 300. They are made of Q235B steel plate and fixed to a predetermined position on the inner wall of the protective sleeve 300 by welding. The installation position of the brackets 401 needs to be accurately measured and positioned. Typically, one set is installed every 6-12 meters along the sleeve axis. During installation, the center lines of the brackets 401 of the two sets of limiting components should be on the same horizontal plane, with the elevation deviation controlled within ±2mm.

[0033] Each unidirectional limiting component is hinged to the bracket 401 via a pin 402. The pin 402 can be made of 40Cr alloy steel, with a diameter determined by load-bearing calculations, typically 20-40mm. The limiting plate 403 has a triangular prism structure and can be integrally cast from ZG270-500 cast steel. Its right-angled edges are machined with pin holes of 22-42mm in diameter, and the pin holes and pin 402 are fitted with an H9 / f9 tolerance. During installation, the bracket 401 is first securely welded to the inner wall of the protective sleeve 300. Then, the limiting plate 403 is connected to the bracket 401 via the pin 402. Finally, a cotter pin is installed to prevent the pin 402 from falling off.

[0034] The working process of the limiting plate 403 is as follows: When the pipeline is lowered, the disc clamp 200 pushes the inclined surface of the limiting plate 403 downward to rotate, causing the limiting plate 403 to rotate clockwise around the pin 402 to the horizontal limiting state; when the pipeline is lifted, the clamp pushes the right-angled surface of the limiting plate 403 upward to rotate the limiting plate 403 counterclockwise to the open state. The rotation angle of the limiting plate 403 is controlled by the mechanical limiting block on the bracket 401, with a maximum rotation angle of 90 degrees. This structure utilizes the geometric characteristics of a triangular prism to achieve a unidirectional limiting function while ensuring load-bearing strength, making pipeline installation and maintenance operations safer and more reliable.

[0035] In another technical solution, the vertical delivery system pipeline 100 of the emulsion matrix includes an emulsion matrix delivery pipeline 101, a sensitizer delivery pipeline 102, and a communication pipeline 103 that are parallel to each other. The disc hanger 200 is formed by two semi-cylindrical hanger assemblies 201 that are connected and fixed together by fastening bolts 202. The opposite sidewalls of the two hanger assemblies 201 are provided with arc-shaped grooves 203 that match the emulsion matrix delivery pipeline 101, the sensitizer delivery pipeline 102, and the communication pipeline 103.

[0036] In the above technical solution, the vertical delivery system for the emulsified matrix includes three parallel pipelines with different functions. The emulsified matrix delivery pipeline 101 can be made of seamless stainless steel, specifically 06Cr19Ni10; the sensitizer delivery pipeline 102 can be made of SCH40 seamless steel, specifically 20# steel; and the communication pipeline 103 can be made of HDPE pipe, specifically PE100 grade high-density polyethylene. The three pipelines are arranged in parallel in a triangular or straight pattern. The center-to-center distance between the pipelines is determined by calculating thermal expansion and installation clearance, typically maintaining a spacing of 100-150 mm.

[0037] The disc-shaped hanger 200 adopts a split structure, consisting of two semi-cylindrical hanger components 201 assembled from left and right sides. The hanger components 201 can be made of ZG270-500 cast steel, and each component has three arc-shaped grooves 203 machined on its inner side. The radii of the grooves are matched to the corresponding pipe outer diameter, with tolerances controlled within ±0.5mm. The groove surfaces can be coated with epoxy resin to prevent pipe abrasion. The two hanger components 201 are fixed together by fastening bolts 202.

[0038] During installation, the three pipes are first temporarily fixed according to the designed spacing. Then, one side of the lifting clamp assembly 201 is installed from the side of the pipe, and the other side assembly is then closed. Finally, the fastening bolts 202 are tightened symmetrically, with the bolt pre-tightening torque controlled at 100-200 Nm. The final installation position of the lifting clamp assembly 201 is 500-800 mm from the end of the pipe; this distance is determined by calculating the pipe bending moment. This structure can simultaneously clamp three pipes and maintain their relative position stability, allowing multiple pipes to be lifted as a whole, improving installation efficiency and ensuring the integrity of the piping system.

[0039] In another technical solution, the dimensions of the protective sleeve 300 and the disc hanger 200 are determined by the following method: 300 outer diameter sleeve s With shaft diameter D h Well wall design clearance c h Satisfying: Ds≤D h -2c h ; 300 inner diameter d of the protective sleeve s With wall thickness t s Satisfy: d s =D s -2t s ; The outer diameter D of the disc hanger 200 d The interference prevention conditions of the limit plate 403 in both the closed and open states must be met simultaneously: In the closed state, the following condition is satisfied: D d ≤d s -2(e p +c d ); When enabled, the following condition is met: D d ≤d s -2(e p ×cosβ open +c d ); Among them, e p c represents the radial protrusion of the unidirectional limiting component as a whole. d For the installation gap, β open The opening angle of the limit plate; 200mm center hole radius R of disc hanger h It must be greater than the minimum envelope radius R of the three pipes: emulsion matrix delivery pipe 101, sensitizer delivery pipe 102, and communication pipe 103. bundle Installation gap c d The sum, i.e., R h ≥R bundle +c d This is to ensure that the three tubes can pass through smoothly and maintain the gap.

[0040] In the above technical solution, the dimensions of the protective sleeve 300 and the disc hanger 200 are determined according to a specific design method. The protective sleeve 300 can be a spiral welded pipe, and the material can be Q235B carbon structural steel. Its outer diameter D... s Based on the vertical shaft diameter D h and well wall design clearance c h Determined, where c h Typically, 50-100mm is used to satisfy D. s ≤D h -2c h The relationship. The wall thickness t of the 300mm protective sleeve. s A diameter of 10-20mm can be selected, with an inner diameter d. s Through formula d s =D s -2t s Calculations show that the casing has sufficient structural strength.

[0041] The outer diameter D of the disc hanger 200 d It needs to meet the bidirectional anti-interference condition. With the limit plate closed, D... d ≤d s -2(e p +c d ), where e p The radial protrusion of the unidirectional limiting component is typically 30-50mm. d For installation clearance, a value of 10-20mm is typically used. In the open state, D... d ≤d s -2(e p ×cosβ open +c d ), where β open The opening angle of the limit plate is typically 90 degrees. The 200mm disc hanger can be made of ZG270-500 cast steel, with a center hole radius R. h It must be greater than the minimum envelope radius R of the three tubes. bundle Installation gap c d The sum, i.e., R h ≥R bundle +c d Rbundle It is calculated using the outer diameter and spacing of the three tubes.

[0042] In practical applications, firstly, based on the shaft diameter D... h Determine the outer diameter D of the 300mm outer diameter sleeve. s Then, select the wall thickness t according to the structural strength requirements. s And calculate the inner diameter d s Next, based on the dimensional parameters e of the unidirectional limiting component... p and c d Calculate the maximum permissible outer diameter of the disc hanger 200 in both the closed and open states, and take the smaller value as D. d The design value. Finally, R is calculated based on the outer diameter and arrangement of the three pipes. bundle Determine the radius R of the center hole of the 200mm disc hanger. h This method, through systematic dimensional design, ensures the proper fit between the protective sleeve 300, the disc hanger 200, and the piping system, thus avoiding mechanical interference during installation and operation.

[0043] This dimensional design method provides clear design guidelines, ensuring proper clearance between components and preventing jamming or collisions. Calculated parameter values ​​ensure that the retaining sleeve 300 and the disc hanger 200 meet both strength requirements and good assembly performance. The entire design process considers the motion requirements under both lowering and lifting conditions, ensuring reliable system operation under different states.

[0044] In another technical solution, the minimum envelope radius R of the three pipes—emulsion matrix delivery pipe 101, sensitizer delivery pipe 102, and communication pipe 103—is... bundle satisfy: ; Where, r m r is the radius of the emulsion matrix delivery pipe. sen r is the radius of the sensitizer delivery pipeline. c Let g be the radius of the communication channel. pp This refers to the net installation distance between the three pipes.

[0045] In the above technical solution, the minimum envelope radius R of the three pipes—emulsion matrix delivery pipe 101, sensitizer delivery pipe 102, and communication pipe 103—is... bundleThe determination needs to be made through mathematical formulas. The emulsion matrix delivery pipe 101 can be a seamless stainless steel pipe with an outer diameter of 89mm, and the material can be 06Cr19Ni10; the sensitizer delivery pipe 102 can be a seamless SCH40 steel pipe with an outer diameter of 60mm, and the material can be 20# steel; the communication pipe 103 can be an HDPE pipe with an outer diameter of 50mm, and the material can be PE100 grade high-density polyethylene. The three pipes are arranged in a triangular pattern, and the installation clearance g between the pipes is... pp The thickness is usually 50-100mm, and the specific value is determined based on the thermal expansion of the pipeline and the installation requirements.

[0046] Minimum envelope radius R bundle The calculation formula is: R bundle = max{r m , r sen , r c} + g pp , where r m r is the radius of the emulsion matrix delivery pipe. sen r is the radius of the sensitizer delivery pipeline. c Let g be the radius of the communication duct. In practical calculations, it is necessary to calculate the actual outer radius of the three types of ducts separately, and take the maximum value plus the installation clearance g between the ducts. pp For example, when r m =44.5mm, r sen =30mm, r c =25mm, g pp When =75mm, R bundle =44.5 + 75 = 119.5 mm. This value needs to be rounded to the standard machining size, usually 120 mm.

[0047] To ensure the three pipes can pass smoothly through the center hole of the 200mm disc hanger, simulation verification is required before actual installation. This can be achieved by creating a physical model of the three pipes, fixing them according to the designed spacing, and measuring their actual envelope circle diameter. Alternatively, virtual assembly can be performed using 3D modeling software to check if the gap between the pipes and the center of the hanger meets the requirements. During installation, the three pipes are temporarily fixed with pipe clamps to maintain the designed spacing, and then the entire assembly is inserted into the center hole of the 200mm disc hanger. This method, by accurately calculating the minimum envelope radius of the three pipes, provides a basis for the design of the center hole dimensions of the 200mm disc hanger, ensuring the smooth installation of the multi-pipe system.

[0048] This calculation method can accurately determine the minimum envelope size of a multi-pipe system, providing reliable data support for the design of the disc hanger 200. By considering the actual outer diameter of the pipe and the installation spacing, interference between the pipe and the hanger is avoided. The calculation process is simple, clear, and easy to implement, ensuring smooth installation of the multi-pipe system. This method is applicable to pipe combinations of different specifications, exhibiting good versatility and practicality.

[0049] In another technical solution, the minimum net distance g between the outer edge of the emulsion matrix delivery pipe, the sensitizer delivery pipe, and the communication pipe and the inner wall of the 300mm protective sleeve is... pc Interference prevention conditions must be met: .

[0050] In the above technical solution, the minimum net distance g between the outer edge of the emulsion matrix delivery pipe, the sensitizer delivery pipe, and the communication pipe and the inner wall of the 300mm protective sleeve is... pc Specific anti-interference conditions need to be met. For the 300mm protective sleeve, spiral welded pipe can be selected, and the material can be Q235B carbon structural steel, with an inner diameter d... s The diameter is determined according to design requirements, typically 500-800mm. The three pipes are arranged in a triangular pattern. The emulsion matrix delivery pipe can be a seamless steel pipe with an outer diameter of 89mm, the sensitizer delivery pipe can be a SCH40 steel pipe with an outer diameter of 60mm, and the communication pipe can be an HDPE pipe with an outer diameter of 50mm.

[0051] Minimum net distance g pc The formula for calculating g is: pc ≥ (d s - 2×R bundle ) / 2, where R bundle Let g be the minimum envelope radius of the three tubes. In practical engineering, g pc A gap of no less than 50mm is typically required. This value takes into account factors such as pipe installation errors, thermal expansion deformation, and construction tolerances. During installation, the three pipes are bundled together using pipe clamps, with the bundle centered on the protective sleeve 300. The gap is evenly distributed in the circumferential direction by adjusting the bracket 401.

[0052] To ensure the minimum clearance meets requirements, clearance verification is necessary before installation. A laser rangefinder can be used to measure the actual distance between the outer edge of the pipe bundle and the 300mm inner wall of the casing. Measurements should be taken at 45-degree intervals along the circumference, for a total of 8 points. The clearance value at all measuring points should be greater than the designed minimum clearance g. pc Alternatively, a 1:1 physical model can be made for trial assembly to check for any interference. This method, combining quantitative calculations and practical verification, ensures that the three-pipe system maintains a sufficient safe distance from the 300mm inner wall of the protective sleeve.

[0053] This calculation method provides a clear basis for the clearance design between the piping system and the 300mm sleeve, effectively preventing mechanical interference during installation and operation. By maintaining the necessary minimum clearance, sufficient space is provided for pipeline thermal expansion and vibration, reducing the risk of collision between the pipeline and the sleeve. This design method considers various uncertainties in actual engineering, improving the reliability and safety of pipeline system installation.

[0054] In another technical solution, the maximum permissible value of the axial pitch s between two adjacent unidirectional limiting structures 400 is... max The following constraints must be met simultaneously: s max The allowable bearing capacity T between the disc hanger 200 and the one-way limiting structure 400 d,allow The allowable load-bearing capacity T of the connecting pin pin,allow The total safe bearing capacity T of the two steel wire ropes rope,tot The minimum value among the requirements for wire rope elongation control is determined together with the requirements for wire rope elongation control. Furthermore, the safety verification under single wire rope failure conditions must be met, meaning the single-span load must be less than the allowable bearing capacity T of a single wire rope. rope,1 ,Right now: ; Among them, single span load Δs max EA is the maximum elongation of the wire rope. eff This represents the equivalent axial stiffness of the two steel wire ropes.

[0055] In the above technical solution, the maximum allowable value of the axial pitch s between two adjacent unidirectional limiting structures 400 is s max The determination requires comprehensive calculation of multiple factors. The unidirectional limit structure 400 can use standard industrial limit switch components, its bracket 401 can be made of Q235B steel plate, and the limit plate can be made of ZG270-500 cast steel. The connecting pin can be made of 40Cr alloy steel, with a diameter typically 20-40mm. The wire rope can be of type 6×37+FC, with a diameter determined based on load calculations, typically 20-28mm.

[0056] s max The calculation needs to consider four constraints simultaneously: the allowable bearing capacity T between the disc hanger 200 and the unidirectional restraint structure 400. d,allow The calculated value is based on the allowable bearing capacity T of the connecting pin. pin,allow The calculated value is based on the total safe bearing capacity T of the two wire ropes. rope,tot The calculated values, and the calculated values ​​based on the wire rope elongation control requirements. Among them, the single-span load W... span Through formula Wspan = w pipe ×s max Calculate, w pipe The weight per unit length of the pipe, typically 200-500 N / m. Maximum elongation of the wire rope Δs. max Controlled within 0.5% of the span, i.e., Δs max ≤0.005×s max In addition, a failure condition verification of a single wire rope is required to ensure that the load on a single span is less than the allowable bearing capacity T of a single wire rope. rope,1 .

[0057] In practical engineering applications, it is first necessary to determine the individual bearing capacity parameters: T d,allow The smaller value is taken from the contact stress and shear stress calculations, typically 50-100 kN; T pin,allow The smaller value is taken from the double shear strength and bearing compressive strength calculations, typically 30-80 kN; T rope,tot Based on the breaking force calculation of the wire rope, the safety factor γ r Take a value between 2.5 and 3.0. Then calculate s under each constraint condition. max The minimum value is taken as the design value. During installation, the bracket 401 is accurately positioned and welded on the inner wall of the 300mm retaining sleeve according to the calculated pitch, with the positional tolerance controlled within ±2mm.

[0058] This calculation method, through comprehensive consideration of multiple factors, provides a scientific basis for the arrangement spacing of the 400mm unidirectional restraint structure. By considering both normal operating conditions and single-rope failure conditions, it ensures the safety and reliability of the system under various circumstances. The control requirements for wire rope elongation guarantee the stability of the system during hoisting. This method can calculate the optimal pitch value based on specific pipeline parameters and wire rope characteristics, improving economy while ensuring safety. The entire calculation process is comprehensive and provides reliable technical support for practical engineering applications.

[0059] In another technical solution, the load-bearing capacity T of a single steel wire rope rope,1 Calculated by the following formula: Total safe load capacity T of the two steel wire ropes rope,tot and equivalent axial stiffness EA eff Calculated using the following formulas respectively: , ; Among them, T MBL η is the minimum breaking force of a single wire rope. term For termination efficiency, η b For bending efficiency, η share γ is the load distribution factor.r Where is the safety factor of the wire rope, Er is the elastic modulus of the wire rope, and Ar is the metal cross-sectional area of ​​the wire rope.

[0060] In the above technical solution, the load-bearing capacity and stiffness parameters of the wire rope need to be determined through calculation formulas. The wire rope can be a standard 6×37+FC type, and the wire can be galvanized steel wire with a strength grade of 1570MPa or 1770MPa. The core can be a fiber core, and the ends can be zinc alloy cast joints. The minimum breaking force T of a single wire rope... MBL You can find the specifications for the wire rope's diameter and strength grade from the product standard. Typically, a 20mm diameter wire rope has a T... MBL A steel wire rope T with a diameter of approximately 28mm and a strength of approximately 200kN. MBL Approximately 400kN.

[0061] The load-bearing capacity T of a single steel wire rope rope,1 From formula T rope,1 =(T MBL ×η term ×η b ) / γ r Calculate the termination efficiency η. term We can take 0.8, and the bending efficiency η b A value of 0.9 can be used, with a safety factor γ. r Take 2.5. The total safe bearing capacity T of the two wire ropes. rope,tot From formula T rope,tot =2×T rope,1 ×η share Calculate the load distribution factor η share Take 0.9. Equivalent axial stiffness EA eff From formula EA eff =2×E r ×A r The calculations are performed, where the elastic modulus Er of the steel wire rope can be taken as 100 GPa, and the cross-sectional area of ​​the metal is A. r The value of A for a 20mm diameter wire rope can be obtained by referring to a table. r Approximately 150mm 2 .

[0062] In practical applications, T is first determined based on the wire rope diameter and strength grade. MBL The value is then calculated sequentially according to the formula to obtain T. rope,1 T rope,tot and EA effThese calculations need to be completed before wire rope installation to ensure that the selected wire rope meets the load-bearing requirements. During installation, the wire rope is tensioned using a winch, with the tension force controlled within 20%-30% of the single wire rope's load-bearing capacity. After installation, pre-stretching is required to eliminate initial elongation and ensure stability during hoisting.

[0063] This calculation method provides a quantitative basis for the selection and safe use of wire ropes. By considering practical factors such as end-joint efficiency, bending efficiency, and load distribution coefficient, the calculation results are closer to actual engineering conditions. The introduction of a safety factor ensures that the wire rope has sufficient safety margin during use. The calculation of equivalent axial stiffness provides basic data for system deformation analysis. This method can guide engineers in the scientific selection of wire ropes, ensuring the safety and reliability of hoisting operations.

[0064] In another technical solution, the allowable load-bearing capacity T between the disc-shaped clamp 200 and the one-way limiting structure 400 is... d,allow The smaller value calculated based on the allowable contact stress of the material and the value calculated based on the allowable shear stress is taken, and the calculation formula is as follows: ; where σ c,allow For the allowable contact stress of the material, b p For the contact width, L cont For the effective contact length, τ allow For the allowable shear stress of the material, t d The thickness of the disk; Permissible load capacity T of connecting pin pin,allow The smaller value calculated based on the pin-shaft double shear strength and the value calculated based on the bearing strength is taken, and the calculation formula is as follows: ; where n pin d represents the number of pins. pin τ is the diameter of the pin. allow For the allowable shear stress of the pin material, σ c,allow t is the allowable contact stress of the pin. d The thickness of the stressed component.

[0065] In the above technical solution, the allowable bearing capacity T between the disc-shaped clamp 200 and the one-way limiting structure 400 is... d,allow It needs to be determined through a dual calculation method. The disc-shaped clamp 200 can be made of ZG270-500 cast steel, and its contact surface can be hardened to improve wear resistance. The limiting plate of the unidirectional limiting structure 400 can be made of Q345 steel plate, and a wear-resistant layer can be welded onto the contact area. Contact width b p Typically, the effective contact length L is 50-100mm. cont Take 80% of the thickness of the disc hanger (200mm), and the thickness of the disc is t.d It is usually 30-50mm.

[0066] T d,allow Take the smaller value between the value calculated based on the allowable contact stress and the value calculated based on the allowable shear stress. Allowable contact stress σ c,allow For ZG270-500 cast steel, a shear stress of 120 MPa can be used, with an allowable shear stress τ. allow A value of 80 MPa can be used. In actual calculations, these two values ​​need to be calculated separately, and then the smaller value is taken as T. d,allow The design value.

[0067] Permissible load capacity T of connecting pin pin,allow This also requires a dual calculation method. The pin can be made of 40Cr alloy steel, after quenching and tempering. The pin diameter d... pin Typically 20-40mm, quantity n pin Typically 2-4. The allowable shear stress τ of the pin material. allow 120MPa can be taken, and the allowable contact stress σ c,allow 200 MPa can be taken. Thickness t of the load-bearing component. d The thickness is typically 20-40mm, referring to the thickness of the lug plate that mates with the pin.

[0068] T pin,allow The smaller value between the value calculated based on the pin-shaft double shear strength and the value calculated based on the bearing strength is taken. In practical applications, these two values ​​need to be calculated separately, and then the smaller value is taken as T. pin,allow The final design value. When installing the pin, it is necessary to ensure the fit accuracy with the pin hole, typically using a fit tolerance of H8 / f7.

[0069] This dual calculation method provides a reliable basis for the strength design of critical connecting components. By calculating contact stress and shear stress separately, the safety of the structure under various stress states is ensured. The conservative approach of taking the smaller value as the design value provides an additional safety margin for the system. This method considers a variety of stress conditions that may occur in actual engineering projects, and can effectively prevent structural failure accidents. The calculation process is clearly defined, facilitating engineering application and implementation.

[0070] In another technical solution, the length L of a single pipe section must simultaneously meet the following conditions: ; ; Among them, L hand,min L is the minimum maneuverable pipe length. lift,max H is the maximum pipe length that the lifting equipment can safely lift, H is the total depth of the shaft, and N is the maximum pipe length that the lifting equipment can safely lift. j,maxThis represents the maximum number of connectors allowed by the system.

[0071] In the above technical solution, determining the length L of a single pipe section requires comprehensive consideration of multiple constraints. A standard length of seamless steel pipe can be selected for each pipe section, and the material can be Q235B or 20# steel. The pipe connection can be a flange connection, and SO series standard flanges can be selected, with Q235B material. The flange gasket can be an asbestos rubber gasket or a polytetrafluoroethylene gasket, and the bolts can be 8.8 grade high-strength bolts.

[0072] The length L of a single pipe section must simultaneously meet four conditions: it must not be less than the minimum maneuverable pipe length L. hand,min Typically, it is 1.5-2.0 meters; it should not exceed the maximum pipe length L that the lifting equipment can safely lift. lift,max The value is determined based on the crane's rated lifting capacity and hoisting height, typically ranging from 6 to 12 meters; it must be an integer multiple of the total shaft depth H; and it must not exceed the system's maximum allowable number of joints N. j,max The number of joints is typically controlled within 20-30. These parameters need to be calculated and determined based on specific engineering conditions.

[0073] In practical engineering applications, L is first determined based on the performance of the on-site lifting equipment. lift,max Then, considering the ease of manual operation, L was determined. hand,min Next, based on the total shaft depth H and the maximum allowable number of joints N... j,max The maximum theoretical value of the pipe length is calculated. The final determined length L of a single pipe section needs to satisfy all these conditions simultaneously, and the minimum value among them is taken. The pipe is prefabricated in the prefabrication yard, including cutting, beveling, flange welding, and other processes, and then transported to the site for installation.

[0074] This multi-factor comprehensive approach provides a scientific basis for selecting the length of a single pipe section. By taking into account factors such as lifting equipment capacity, manual operation requirements, shaft depth, and system reliability, it ensures the feasibility and safety of pipeline installation. This method can determine the optimal pipe section length based on specific engineering conditions, improving installation efficiency while ensuring construction safety. Simultaneously, by controlling the number of joints, it reduces potential leakage points and improves the overall reliability of the pipeline system.

[0075] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for installing pipelines in a vertical delivery system for emulsified matrix, characterized in that, Includes the following steps: Step 1: Pre-assemble the vertical delivery system pipeline of the emulsion matrix into multiple single-section pipelines, and install disc hangers on the outer periphery of each single-section pipeline; Step 2: Install the pre-assembled vertical delivery system pipeline with disc hangers into a protective sleeve, and install multiple sets of one-way limiting structures corresponding to the disc hangers at intervals along the axial direction on the inner side wall of the protective sleeve. Then, pass through and connect multiple disc hangers in sequence with two steel wire ropes. Step 3: Lower the protective sleeve obtained in Step 2, along with the pre-assembled emulsified matrix vertical delivery system pipeline with disc hanger, into the shaft, and pour concrete into the annular space between the protective sleeve and the shaft wall to fix it. When the disc hanger moves downward along the protective sleeve of the vertical conveying system pipeline of the emulsion matrix, it pushes the one-way limiting structure to rotate clockwise to the limiting state, supporting the corresponding disc hanger. As the disc hanger moves upward along the protective sleeve of the vertical delivery system pipeline for the emulsion matrix, it pushes the one-way limiting structure to rotate counterclockwise to the open state, allowing the disc hanger to pass through.

2. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 1, characterized in that, Each set of unidirectional limiting structures includes two symmetrical unidirectional limiting components. Each unidirectional limiting component is provided with a bracket fixed to the inner wall of the protective sleeve and a limiting plate hinged to the bracket by a pin. The limiting plate is a triangular prism structure, and the pin is hinged to the right-angle edge of the limiting plate.

3. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 2, characterized in that, The vertical delivery system pipeline for the emulsified matrix includes parallel emulsified matrix delivery pipelines, sensitizer delivery pipelines, and communication pipelines. The disc hanger is formed by two semi-cylindrical hanger assemblies connected and fixed together by fastening bolts, and the opposite sidewalls of the two hanger assemblies are provided with arc-shaped grooves that match the emulsified matrix delivery pipelines, sensitizer delivery pipelines, and communication pipelines.

4. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 3, characterized in that, The dimensions of the protective sleeve and the disc hanger are determined according to the following method: Outer diameter D of the protective sleeve s With shaft diameter D h Well wall design clearance c h Satisfying: Ds≤D h -2c h Inner diameter d of the protective sleeve s With wall thickness t s Satisfy: d s =D s -2t s ; The outer diameter D of the disc hanger d The interference prevention conditions of the limit plate must be met simultaneously in both the closed and open states: In the closed state, the following condition is satisfied: D d ≤d s -2(e p +c d ); When enabled, the following condition is met: D d ≤d s -2(e p ×cosβ open +c d ); Among them, e p c represents the radial protrusion of the unidirectional limiting component as a whole. d For the installation gap, β open The opening angle of the limit plate; The radius R of the center hole of the disc hanger h It must be greater than the minimum envelope radius R of the three pipes: the emulsion matrix delivery pipe, the sensitizer delivery pipe, and the communication pipe. bundle Installation gap c d The sum, i.e., R h ≥R bundle +c d This is to ensure that the three tubes can pass through smoothly and maintain the gap.

5. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 4, characterized in that, The minimum envelope radius R of the three pipes: the emulsion matrix delivery pipe, the sensitizer delivery pipe, and the communication pipe. bundle satisfy: ； Where, r m r is the radius of the emulsion matrix delivery pipe. sen r is the radius of the sensitizer delivery pipeline. c Let g be the radius of the communication channel. pp This refers to the net installation distance between the three pipes.

6. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 5, characterized in that, Minimum clearance g between the outer edge of the emulsion matrix delivery pipeline, sensitizer delivery pipeline, and communication pipeline and the inner wall of the protective sleeve. pc Interference prevention conditions must be met: .

7. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 6, characterized in that, The maximum permissible value of axial pitch s between two adjacent unidirectional limiting structures max The following constraints must be met simultaneously: s max The allowable bearing capacity T between the disc hanger and the one-way limiting structure d,allow The allowable load-bearing capacity T of the connecting pin pin,allow The total safe bearing capacity T of the two steel wire ropes rope,tot The minimum value among the requirements for wire rope elongation control is determined together with the requirements for wire rope elongation control. Furthermore, the safety verification under single wire rope failure conditions must be met, meaning the single-span load must be less than the allowable bearing capacity T of a single wire rope. rope,1 ,Right now: ； Among them, single span load Δs max EA is the maximum elongation of the wire rope. eff This represents the equivalent axial stiffness of the two steel wire ropes.

8. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 7, characterized in that, The load-bearing capacity T of a single steel wire rope rope,1 Calculated by the following formula: Total safe load capacity T of the two steel wire ropes rope,tot and equivalent axial stiffness EA eff Calculated using the following formulas respectively: ， ； Among them, T MBL η is the minimum breaking force of a single wire rope. term For termination efficiency, η b For bending efficiency, η share γ is the load distribution factor. r Where is the safety factor of the wire rope, Er is the elastic modulus of the wire rope, and Ar is the metal cross-sectional area of ​​the wire rope.

9. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 7, characterized in that, The allowable bearing capacity T between the disc hanger and the one-way limiting structure d,allow The smaller value calculated based on the allowable contact stress of the material and the value calculated based on the allowable shear stress is taken, and the calculation formula is as follows: ; where σ c,allow For the allowable contact stress of the material, b p For the contact width, L cont For the effective contact length, τ allow For the allowable shear stress of the material, t d The thickness of the disk; Permissible load capacity T of connecting pin pin,allow The smaller value calculated based on the pin-shaft double shear strength and the value calculated based on the bearing strength is taken, and the calculation formula is as follows: ; where n pin d represents the number of pins. pin τ is the diameter of the pin. allow For the allowable shear stress of the pin material, σ c,allow t is the allowable contact stress of the pin. d The thickness of the stressed component.

10. The installation method of the pipeline for the vertical delivery system of emulsified matrix as described in claim 1, characterized in that, The length L of a single pipe section must meet the following conditions simultaneously: ； ； Among them, L hand,min L is the minimum maneuverable pipe length. lift,max H is the maximum pipe length that the lifting equipment can safely lift, H is the total depth of the shaft, and N is the maximum pipe length that the lifting equipment can safely lift. j,max This represents the maximum number of connectors allowed by the system.

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