Safety cable branch box

Abstract

The invention relates to a safe cable branch box, and relates to the technical field of electrical equipment, the safe cable branch box comprises a box body, an inner cavity of the box body is divided into a plurality of independent installation chambers through partition plates, and a graded pressure relief device is arranged at a box body opening corresponding to each installation chamber. The graded pressure relief device comprises a fixed frame connected with the box body through a hinge, a buffer frame connected with the fixed frame in a sliding mode, and a pressure relief plate fixed to the buffer frame through a shearing bolt assembly. The buffering frame, the guiding buffering mechanism and the shearing bolt assembly form a two-stage pressure relief response mechanism. The cable branch box achieves the technical effects that air pressure rise in the cable branch box is effectively buffered and directionally and completely relieved through a graded pressure relief mechanism, and safe and stable operation of the cable branch box is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical equipment, in particular to a safe cable branch box. BACKGROUND

[0002] In the field of electrical equipment, cable branch boxes, as important infrastructure, are widely used in urban power grids, industrial plants and other places, playing a key role in distributing power and connecting different cable lines. With the continuous development of the power system, the use of cable branch boxes is increasingly expanding, and their safety and reliability are crucial to ensuring the stability of power supply. They can distribute the power input by one cable to multiple cable outputs to meet the power needs of different users, and play an important role in improving power supply efficiency and optimizing power grid layout.

[0003] In related technologies, to deal with the problem of internal pressure rise, the following methods are commonly used. One is to set a normal pressure relief plate, which directly breaks when the internal pressure of the box rises to a certain extent, releasing the internal pressure to the outside. This method has a relatively simple structure and low cost, and is a common pressure relief method. Another is to use a safety valve, which sets the opening pressure of the safety valve. When the pressure reaches this value, the safety valve opens to relieve pressure. Another is to use the elastic deformation of the box to absorb some pressure. Through the elastic properties of the box material, a certain deformation occurs when the pressure rises, thereby relieving internal pressure.

[0004] However, once the ordinary pressure relief plate breaks, it cannot be restored, resulting in unnecessary and destructive complete pressure relief, affecting the continuity of power supply and the availability of equipment. The opening pressure of the safety valve is relatively fixed and difficult to adapt to different degrees of internal failure, which may result in misoperation or failure to relieve pressure in time and effectively in the event of a serious failure. The method of using the elastic deformation of the box to absorb pressure has limited buffering capacity, and when the pressure is too high, it cannot provide sufficient buffering and pressure relief effect, which may cause the box to explode structurally and pose a threat to surrounding equipment and personnel safety. SUMMARY

[0005] The purpose of the present application is to overcome the above technical problems and provide a safe cable branch box.

[0006] A safe cable branch box includes a box body, the inner cavity of the box body is divided into multiple independent installation cavities by a partition plate, and a staged pressure relief device is arranged at the opening of the box body corresponding to each installation cavity. The staged pressure relief device includes: A fixed frame is rotatably connected to the surface of the box body by a hinge and is locked by a locking assembly. a buffering frame is slidably connected with the fixed frame through at least one guiding and buffering mechanism, so that the buffering frame can move relative to the fixed frame in a direction away from or close to the installation cavity; A first sealing element is arranged between the fixed frame and the buffering frame to form a dynamic seal therebetween; a pressure relief plate is fixedly connected with the buffering frame through a shear bolt assembly, and the pressure relief plate is provided with an outwardly protruding deformation guide on a side thereof facing the installation cavity; A second sealing element is arranged between the pressure relief plate and the buffering frame; The buffering frame, the guiding and buffering mechanism, and the shear bolt assembly cooperate to form a two-stage pressure relief response mechanism for the pressure rise in the installation cavity: when the pressure rises to a first threshold value, the buffering frame is pushed to slide against the resistance of the guiding and buffering mechanism to expand the volume of the installation cavity, thereby realizing first-stage buffering pressure relief; when the pressure continues to rise to a higher second threshold value, the deformation guide of the pressure relief plate deforms enough to cause the shear bolt assembly to break, the pressure relief plate separates from the buffering frame and opens around the hinge, thereby realizing second-stage directional complete pressure relief. By adopting the above technical solutions, intelligent staged management of pressure is realized, different degrees of internal faults can be effectively distinguished and differentiated, unnecessary destructive pressure relief and unplanned power outage can be avoided, and power supply continuity is improved; when a serious fault occurs, the box can be prevented from being structurally burst or severely deformed due to internal pressure accumulation, and the safety of other electrical equipment in the box and surrounding personnel is protected; each installation cavity is equipped with an independent staged pressure relief device, forming a safety architecture of partition isolation and independent protection, which facilitates rapid positioning of fault points and supports independent maintenance and resetting of the fault unit, thereby improving the overall maintainability of the large box.

[0007] Optionally, a side of the pressure relief plate is provided with a hooking edge bent towards the buffering frame; the buffering frame is provided with an outwardly turned edge corresponding to the position of the hooking edge; wherein the end of the hooking edge and the outwardly turned edge have a preset gap in the initial state; the preset gap is smaller than the initial displacement of the pressure relief plate relative to the buffering frame at the moment of breakage of the shear bolt assembly, so that after the breakage of the shear bolt assembly, the pressure relief plate moves outward by the preset gap, and then the hooking edge is hooked on the outwardly turned edge, forming a mechanical linkage.

[0008] By adopting the above technical scheme, the core technical problem of the action reliability of the second-stage pressure relief is solved, in the moment of the fracture of the shear bolt and the disconnection of the rigid connection, the hooking of the "clamping edge" and the "turned-up edge" immediately establishes a new and forced mechanical linkage between the pressure relief plate and the buffer frame, ensuring that the pressure relief plate can effectively drive the buffer frame and even the entire pressure relief unit to move under the gas thrust, thereby reliably performing the final action of opening around the hinge and avoiding the risk of the pressure relief plate flying off or action jamming; the structure is extremely simple and highly reliable, the interlocking structure can be realized through a sheet metal bending process without introducing additional hinges, connecting rods or complex locking mechanisms, without increasing the number of moving parts and without damaging the original sealing interface, and the purely mechanical interference principle determines high action reliability and environmental adaptability; the triggering is accurate and accurate, and the design of "preset gap less than initial displacement" ensures that the interlocking action only occurs after the effective fracture of the shear bolt, avoiding the mislinkage caused by vibration or other interference and ensuring the strict sequence of the two-stage response. The intelligent graded management of pressure is also realized, breaking through the traditional pressure relief device "all or nothing" single response mode, and through the two-stage mechanism of "first buffering and then complete pressure relief", different degrees of internal faults can be effectively distinguished and differentiated, and for slight pressure fluctuations that can be self-recovered, only the first-stage buffering is triggered, greatly avoiding unnecessary destructive pressure relief and resulting in unplanned power outage, significantly improving power continuity; intrinsically safe and device protection, when an uncontrollable serious fault occurs, the second-stage pressure relief ensures that the explosive pressure and high-temperature plasma can be quickly and completely released, preventing the box from being structurally burst or severely deformed due to internal pressure accumulation, and fundamentally protecting other electrical equipment in the box and surrounding personnel safety; modular independent safety unit, each installation chamber is equipped with an independent graded pressure relief device, forming a "partition isolation and self-protection" safety architecture, the failure and action of a single unit do not affect other units, facilitating quick positioning of the fault point and supporting independent maintenance and resetting of the faulty unit, improving the overall maintainability of the large box.

[0009] Optionally, the guiding and buffering mechanism comprises: a guiding groove opened on the fixed frame; a guiding piece fixed on the buffer frame and extending into the guiding groove; an elastic element arranged in the guiding groove and used for providing a reset elastic force for the buffer frame; and a damper, a cylinder body of the damper is fixed in the guiding groove, and a piston rod of the damper is connected with the buffer frame, and the damper is used for providing damping for the sliding of the buffer frame.

[0010] By adopting the technical scheme, intelligent grading management of pressure is realized, different degrees of internal faults are effectively distinguished and differentiated, unnecessary destructive pressure relief and unplanned power outage are avoided, and power supply continuity is improved; when a serious fault occurs, structural burst or serious deformation of the box due to internal pressure accumulation can be prevented, and the safety of other electrical equipment in the box and surrounding personnel is protected; each installation chamber is equipped with an independent grading pressure relief device, forming a safety architecture of partition isolation and self-protection, facilitating rapid positioning of the fault point and independent maintenance and resetting of the fault unit. At the same time, the guiding and buffering mechanism provides controllable and recoverable first-stage buffering, making the buffering process smooth and controlled, effectively absorbing and dissipating impact energy, realizing the flexibility and reversibility of the first-stage pressure relief; it ensures that the buffering frame moves strictly along the set straight trajectory, preventing it from deviating, being stuck or abnormally worn with the sealing element, and ensuring the smoothness and long-term reliability of the first-stage action; it also provides a solid foundation for the transmission of force during the second-stage pressure relief.

[0011] Optionally, the shear bolt assembly comprises a screw rod and a mounting nut; the screw rod is provided with a fracture-inducing portion with a reduced cross-sectional area on the shank; and the mounting nut presses and fixes the pressure relief plate on the buffering frame, so that the buffering frame forms a shearing action on the screw rod when the pressure relief plate is deformed under stress.

[0012] By adopting the technical scheme, the pressure relief threshold value is accurately set and repeatable, the fracture strength of the bolt is converted into a geometric parameter that can be accurately controlled, the trigger pressure of the second-stage pressure relief can be accurately designed and mass-produced, and the consistency of the safety performance of the product is ensured; at the same time, the fracture is controllable and safe, the guide bolt is sheared and fractured neatly at the predetermined position, the fracture is smooth, there is no dangerous debris flying, and the fractured bolt is easy to replace, realizing the modularization and replaceable design of the pressure relief trigger device.

[0013] Optionally, the deformation guide portion is a prismatic frustum protruding outward, and the plate surface is provided with stress grooves radiating from the center to the periphery.

[0014] By adopting the technical scheme, the prismatic frustum structure can efficiently convert the uniformly distributed gas pressure into bending stress concentrated on the central area, and the stress grooves further guide and amplify the deformation, so that the pressure relief plate plastically deforms in the mode of minimum pressure and maximum displacement when reaching the second threshold value, thereby most effectively converting the deformation into shearing force on the shear bolt; this specific structural design makes the deformation mode of the pressure relief plate highly predictable and consistent, eliminates the threshold fluctuation caused by random deformation, and consolidates the accuracy and reliability of the second-stage pressure relief action.

[0015] Optionally, the guide groove is an annular groove, and the guide member is an annular guide post matched with the annular groove; the first sealing member is arranged on the outer circumferential surface of the annular guide post and is in sliding sealing cooperation with the groove wall of the annular groove, so as to form a closed buffer air chamber between the fixed frame and the buffer frame; the fixed frame is provided with a one-way valve group in communication with the buffer air chamber, for adjusting the air pressure in the buffer air chamber.

[0016] By adopting the above technical scheme, the annular groove is matched with the annular guide post, the first sealing member is in sliding sealing cooperation with the groove wall of the annular groove on the outer circumferential surface of the annular guide post to form a closed buffer air chamber, the intelligent response characteristics of the first-stage buffer are enhanced, the system is less sensitive to small pressure fluctuations, and the possibility of false operation is reduced; the one-way valve group adjusts the air pressure in the buffer air chamber, provides dynamic pressure compensation, ensures the stability of the buffer performance, avoids nonlinear fluctuations of the buffer resistance, ensures smooth and predictable first-stage pressure relief, and simultaneously realizes high-level dynamic sealing, maintains the functional integrity of the buffer air chamber under complex motion, and improves the delicacy and reliability of the entire device. In addition, the cooperation of the guide groove and the guide member ensures that the buffer frame moves strictly along the set straight line trajectory, realizes controllable and recoverable first-stage buffer, creates favorable conditions for the second-stage pressure relief, and enables the buffer process to be smooth and controlled, effectively absorbing and dissipating impact energy. Furthermore, the multiple independent installation chambers cooperate with the staged pressure relief device to realize intelligent staged management of pressure, avoid unnecessary destructive pressure relief and unplanned power outage, improve power supply continuity, prevent structural burst or severe deformation of the box due to internal pressure accumulation, protect other electrical equipment in the box and surrounding personnel, facilitate rapid positioning of fault points, independent maintenance and resetting, and improve the overall maintainability of the large box.

[0017] Optionally, the one-way valve group includes an air inlet one-way valve and an air outlet one-way valve; under normal conditions, the air pressure in the buffer air chamber is lower than the air pressure of the external environment; when the buffer frame slides outward, the air inlet one-way valve is opened to supplement air into the buffer air chamber; when the buffer frame is reset under the action of the elastic element, the air outlet one-way valve is opened to discharge excess air.

[0018] By adopting the above technical scheme, under normal conditions, the negative pressure state of the buffer air chamber provides an additional adjustable starting force threshold for the initial sliding of the buffer frame, the system is less sensitive to small pressure fluctuations, and the possibility of false operation is reduced; through the air inlet one-way valve and the air outlet one-way valve, the air pressure in the buffer air chamber is automatically adjusted during the sliding and resetting of the buffer frame, so that it maintains a stable and small pressure difference with the external environment, avoids nonlinear fluctuations of the buffer resistance caused by changes in the air chamber pressure, and ensures smooth and predictable first-stage pressure relief; the annular sealing member always maintains air tightness during sliding, maintains the functional integrity of the buffer air chamber under complex motion in combination with the one-way valve group, and improves the delicacy and reliability of the entire device.

[0019] Optionally, the annular guide post is provided with a visual indication mark which moves synchronously with the annular guide post, and is used for observing the sliding state of the buffer frame from outside.

[0020] By adopting the above technical scheme, the rapid external diagnosis of the fault is realized, without opening the box or using professional instruments, and the operation and maintenance personnel can remotely and intuitively determine which installation chamber has experienced an internal pressure event and the approximate severity of the event by observing the position change of the indication mark with naked eyes; the indication mark can also provide a basis for condition-based maintenance, and the permanent displacement of the indication mark records the "historical health status" of the equipment, thereby providing valuable on-site data for preventive maintenance and equipment life assessment.

[0021] Optionally, the bottom of the partition plate is provided with a balance air channel which communicates with two adjacent installation chambers, and the balance air channel is provided with a pressure-responsive sealing structure, which closes the balance air channel when the pressure difference between the adjacent chambers is less than a set value, and opens to balance the pressure when the pressure difference exceeds the set value.

[0022] By adopting the above technical scheme, the intelligent hierarchical management of pressure is realized, different degrees of internal faults are effectively distinguished and differentiated, unnecessary destructive pressure relief and unplanned power outage caused thereby are greatly avoided, and power supply continuity is significantly improved; the structural burst or severe deformation of the box due to internal pressure accumulation is prevented, and the safety of other electrical equipment in the box and surrounding personnel is protected; a safety architecture of partition isolation and independent protection is formed, which facilitates rapid positioning of the fault point and supports independent maintenance and resetting of the fault unit, thereby improving the overall maintainability of the large box; the pressure-responsive sealing structure can actively inhibit the rapid accumulation of local pressure in the early stage of the fault, which can sometimes avoid triggering the action of the pressure relief device in the chamber, prevent the expansion of the fault, and even if the pressure relief is still needed, the strength and impact of the pressure relief can be reduced; when the pressure difference decreases, the pressure-responsive sealing structure can restore to the original state, reseal the balance air channel, and ensure the air-tight independence of each chamber under normal conditions, thereby providing an additional passive systematic pressure protection level for the large multi-chamber cable branch box, and further enhancing the overall safety of the product.

[0023] Optionally, the pressure-responsive sealing structure includes a U-shaped partition block made of an elastic material, the middle part of the U-shaped partition block is arranged in the balance air channel, and the two ends of the U-shaped partition block extend into two adjacent installation chambers and form pressure receiving plates; when the air pressure in any installation chamber rises, the corresponding pressure receiving plate is pushed to cause elastic deformation of the U-shaped partition block, thereby opening the balance air channel.

[0024] By adopting the technical scheme, in the extremely early stage of a fault, when the pressure of a single chamber is abnormal but does not reach the self pressure relief threshold, the U-shaped partition block can automatically and timely release part of the pressure between adjacent chambers, plays a role of a flood discharge channel, effectively suppresses the local pressure peak, prevents the fault from escalating due to pressure accumulation, and sometimes can even avoid triggering the action of the pressure relief device, so that the influence of the fault is controlled in the minimum range; through mechanical and self-adaptive pressure balancing, multiple independent chambers can support each other and share the pressure load in an extreme case, thereby enhancing the overall robustness and safety of a large and complex cable branch box when facing an uncertain fault point; the U-shaped partition block is cleverly used in pressure difference and self elasticity, does not need any sensor, controller or external power, realizes the highest reliability, and is lifelong maintenance-free.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. Intelligent hierarchical management of pressure is realized, different degrees of internal faults are distinguished and processed, unnecessary destructive pressure relief and unplanned power outage are avoided, and power supply continuity is improved; 2. When a serious fault occurs, explosive pressure and high-temperature plasma can be quickly and completely released, the box body is prevented from being structurally burst or deformed, and the safety of the equipment in the box and the surrounding personnel is protected; 3. Each installation chamber is provided with an independent hierarchical pressure relief device, forming a partitioned and isolated protection architecture, facilitating positioning of a fault point, supporting independent maintenance and resetting of a fault unit, and improving the maintainability of the box body. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the overall structure of embodiment 1 of the present application; Figure 2 is a schematic diagram of the explosion structure of embodiment 1 of the present application; Figure 3 is Figure 2 is a partial enlarged schematic diagram of part A of Figure 4 is a schematic diagram of embodiment 1 of the present application, mainly embodying a locking assembly; Figure 5 is a schematic diagram of embodiment 1 of the present application, mainly embodying a damper and a spiral spring; Figure 6 is a schematic diagram of embodiment 1 of the present application, mainly embodying a pressure relief plate; Figure 7 is a schematic diagram of embodiment 1 of the present application, mainly embodying a shear bolt assembly; Figure 8 is a schematic diagram of embodiment 2 of the present application, mainly embodying a partition block; Figure 9FIG. 2 is a sectional structure schematic diagram of Embodiment 2 of the present application, mainly embodying the balanced air passage and the air guide groove.

[0027] BRIEF DESCRIPTION OF DRAWINGS: 1, box; 2, partition; 3, mounting chamber; 4, fixed frame; 5, buffer frame; 6, hinge; 601, base; 602, leaf; 603, pivot; 604, reinforcing block; 605, buffer pad; 7, sealing pad; 8, locking assembly; 801, lock core; 802, lock rod; 803, lock post; 9, guide groove; 10, annular guide column; 11, first sealing element; 12, damper; 13, coil spring; 14, air inlet one-way valve; 15, air outlet one-way valve; 16, visual indication mark; 17, pressure relief plate; 1701, deformation guide; 1702, buckling edge; 18, stress groove; 19, turned-up edge; 20, screw rod; 21, mounting nut; 22, induction portion; 23, balanced air passage; 24, partition block; 25, air guide groove; 26, pressure receiving plate; 27, second sealing element. DETAILED DESCRIPTION

[0028] The following will be described in detail below with reference to the accompanying drawings Figure 1 - the accompanying drawings Figure 9 The present application will be described in further detail. Embodiment 1

[0029] A safety cable branch box, referring to Figure 1 , comprising a box 1 and a plurality of hierarchical pressure relief devices arranged in the box 1. The hierarchical pressure relief devices comprise a primary pressure relief mechanism and a secondary pressure relief mechanism. The primary pressure relief mechanism is used to expand the internal volume of the box 1 to achieve buffer pressure relief, avoiding unnecessary and destructive complete pressure relief, greatly improving power supply continuity and device availability. The secondary pressure relief mechanism is used to communicate the inside of the box 1 with the outside to achieve complete pressure relief, completely releasing the ultra-high pressure and high-temperature plasma, preventing the box 1 from structural explosion, and protecting the surrounding equipment and personnel safety. The safety, reliability and maintainability of the outdoor cable branch box in dealing with internal arc faults are significantly improved, and the power loss and operation and maintenance cost caused by misoperation or single point failure are reduced.

[0030] Referring to Figure 1 , Figure 2The box body 1 is fixedly connected with a plurality of partitions 2, which are used to divide the box body 1 into a plurality of independent installation chambers 3. A first pressure relief mechanism and a second pressure relief mechanism are arranged at the opening of the box body 1 in each installation chamber 3. In addition, each installation chamber 3 can install electrical operating devices of different functions, and thus form an incoming line chamber, an operating chamber and an outgoing line chamber, so that the functions of the cable branch box are modularly distributed in each installation chamber 3. If the electrical operating device in one of the installation chambers 3 fails, accurate maintenance can be achieved through the first pressure relief mechanism and the second pressure relief mechanism. In addition, a preset hole for wiring connection of the electrical operating device is formed in the partition 2, and the inner wall of the preset hole is filled with fireclay after the electrical operating device is installed in place, so as to ensure the air-tight independence of each installation chamber 3.

[0031] Referring to Figure 2 The first pressure relief mechanism comprises a fixed frame 4 and a buffer frame 5, and the buffer frame 5 is slidingly connected with the fixed frame 4.

[0032] Referring to Figure 1 , Figure 2 One side of the fixed frame 4 is rotatably connected with the surface of the box body 1 through a hinge 6, and the other side is locked with the surface of the box body 1 through a locking assembly 8, so that the fixed frame 4 can be rotated along the hinge 6 after the locking assembly 8 is opened to open the corresponding installation chamber 3.

[0033] Referring to Figure 2 , Figure 3 The hinge 6 is a heavy external hinge 6, which comprises a base 601, a leaf 602 and a rotating shaft 603. The base 601 is fixedly connected with the surface of the box body 1 by welding. The leaf 602 is fixedly connected with the outer surface of the fixed frame 4 by continuous welding, and a triangular reinforcing block 604 is continuously welded at the position where the leaf 602 deviates from itself and is connected with the fixed frame 4, so as to improve the connection firmness between the leaf 602 and the fixed frame 4. The rotating shaft 603 passes through the bearing sleeve of the base 601 and the shaft hole of the leaf 602 in sequence. One end of the bearing is threaded and locked with a double-nut anti-loose structure to prevent axial movement. In addition, the surface of the base 601 away from the box body 1 is fixedly connected with a buffer pad 605, which is used to abut and collide with the leaf 602 and the reinforcing block 604 when the box body 1 is opened and the opening angle is greater than 90°, so as to provide a force opposite to the rotating direction of the fixed frame 4.

[0034] Referring to Figure 2 The surface of the fixed frame 4 facing the box body 1 is fixedly connected with an annular sealing pad 7, which is tightly attached to the surface of the box body 1 at the opening of the corresponding installation chamber 3, so as to ensure the sealing performance between the installation chamber 3 and the fixed frame 4.

[0035] With reference to Figure 2 , Figure 4 , the locking assembly 8 comprises a lock cylinder 801 embedded in the fixed frame 4, and a lock rod 802 slidingly connected in the fixed frame 4 and driven by the lock cylinder 801. The lock rod 802 is integrally formed with a plurality of lock posts 803 arranged in an array, so that the lock rod 802 can slide towards the box body 1 after the lock cylinder 801 is rotated, and the lock posts 803 are inserted into the lock holes corresponding to the box body 1, thereby realizing the locking and fixing of the fixed frame 4 and the box body 1.

[0036] With reference to Figure 2 , Figure 5 , an annular guide groove 9 is formed on the side surface of the fixed frame 4 away from the box body 1, and an annular guide column 10 is fixedly connected to the side of the buffer frame 5 close to the fixed frame 4. The annular guide column 10 extends into the guide groove 9, and after the buffer frame 5 is installed in place, a gap is provided between the end face of the annular guide column 10 and the groove bottom of the guide groove 9. At the same time, the periphery of the annular guide column 10 is fixedly connected with an annular first sealing member 11, and the first sealing member 11, the annular guide column 10 and the inner wall of the guide groove 9 cooperate to form a closed buffer air chamber between the annular guide column 10 and the groove bottom of the guide groove 9.

[0037] A plurality of dampers 12 are fixedly connected to the groove bottom of the guide groove 9, and the plurality of dampers 12 cooperate to provide damping for the sliding of the buffer frame 5. The plurality of dampers 12 are arranged in an annular array along the guide groove 9. Among them, the cylinder body of the damper 12 is fixedly connected to the fixed frame 4 by screws, the piston rod of the damper 12 penetrates the annular guide column 10 and the buffer frame 5, and is fixed at the end of the buffer frame 5 away from the box body 1 by a fastening nut. In addition, a plurality of elastic elements are fixedly connected to the groove bottom of the guide groove 9, and the elastic element is a helical spring 13, which is used to provide a restoring tension for the buffer frame 5.

[0038] A gas inlet one-way valve 14 and a gas outlet one-way valve 15 are fixedly connected to the side surface of the fixed frame 4, and the gas inlet one-way valve 14 and the gas outlet one-way valve 15 both penetrate the surface of the fixed frame 4 and extend into the buffer air chamber. The gas inlet one-way valve 14 is used to allow the air in the external environment to flow into the buffer air chamber, and the gas outlet one-way valve 15 is used to discharge the excess gas in the buffer air chamber. In addition, after the buffer frame 5 is installed in place, the gas outlet one-way valve 15 is connected to a gas extraction device, so as to extract the gas in the buffer air chamber, so that the side surface of the buffer frame 5 close to the box body 1 abuts against the side surface of the fixed frame 4 away from the box body 1, the piston rod of the damper 12 retracts to the initial position, and the helical spring 13 is in the initial state of release or pre-compression. Moreover, the air pressure in the buffer air chamber is less than the external environment air pressure, so that the external environment can exert a certain pressure on the surface of the buffer frame 5 to maintain the connection stability of the buffer frame 5 and the fixed frame 4.

[0039] When the air pressure in the installation chamber 3 rises and reaches a first threshold value sufficient to push the buffer frame 5 and overcome the atmospheric pressure, the damping force of the damper 12, and the elastic force of the helical spring 13, the rising air pressure in the installation chamber 3 can push the buffer frame 5 to slide away from the fixed frame 4 to expand the volume of the installation chamber 3, realizing the first-stage buffer pressure relief. During the sliding of the buffer frame 5, the volume of the buffer air chamber is synchronously increased, and at this time, the air in the external environment can flow into the buffer air chamber through the air inlet one-way valve 14, thereby stabilizing the pressure exerted by the external environment on the surface of the buffer frame 5, avoiding that the pressure is too large to cause the buffer frame 5 to be blocked during sliding. Conversely, when the air pressure in the installation chamber 3 decreases, the buffer frame 5 is pushed to slide towards the fixed frame 4 under the action of the helical spring 13 and the atmospheric pressure of the external environment, and the excess gas in the buffer air chamber is discharged through the air outlet one-way valve 15.

[0040] The side surface of the annular guide column 10 is provided with visual indication marks 16, which gradually appear during the sliding of the buffer frame 5. By observing the scales or color blocks exposed by the visual indication marks 16 on the side surface, the internal air pressure of the installation chamber 3 can be intuitively understood. In addition, an alarm driven by a photosensitive sensor can be integrated on the annular guide column 10 to issue an alarm at the first time of failure.

[0041] Referring to Figure 2 , Figure 4 , Figure 5 The second-stage pressure relief mechanism is a pressure relief plate 17 mounted on the side surface of the buffer frame 5 away from the box body 1, and a shear bolt assembly for fixing the pressure relief plate 17 on the buffer frame 5. The pressure relief plate 17 forms a “door” for closing the installation chamber 3 through the fixed connection with the buffer frame 5, and a second sealing member 27 is fixedly connected between the pressure relief plate 17 and the buffer frame 5 to ensure the sealing performance of the installation chamber 3.

[0042] Referring to Figure 2 , Figure 5 , Figure 6, the pressure relief plate 17 is integrally formed by punching, cutting and bending of a stainless steel plate. The center of the pressure relief plate 17 is outwardly convex to form a prism-shaped deformation guide 1701. The deformation guide 1701 is processed with six stress grooves 18 on the side facing the inside of the box 1 by laser cutting, and the six stress grooves 18 are evenly radiated from the center to the periphery. In addition, the flat area around the deformation guide 1701 of the pressure relief plate 17 is processed with a plurality of through holes for shearing bolts. At the same time, the outermost edge of the flange edge of the side hinge 6 close to the side edge of the pressure relief plate 17 is bent by 90 degrees to form a vertical buckle 1702. In addition, the surface of the buffer frame 5 is fixedly connected with an everted edge 19 corresponding to the position of the buckle 1702, and the end of the buckle 1702 and the everted edge 19 have a predetermined gap in the initial state, so that the predetermined gap is smaller than the initial displacement of the pressure relief plate 17 relative to the buffer frame 5 at the moment of fracture of the shearing bolt assembly.

[0043] Referring to Figure 5 , Figure 6 , Figure 7 , the shearing bolt assembly includes a screw rod 20 and a matching mounting nut 21. The screw rod 20 is made of alloy steel after quenching and tempering to ensure its basic strength. The surface is blackened or phosphated for rust prevention. A V-shaped fracture inducing portion 22 is precisely processed on the light rod portion of the screw rod 20. The inducing portion 22 is located at the contact plane between the pressure relief plate 17 and the buffer frame 5 after installation. The mounting nut 21 is threadedly connected with the screw rod 20 and is fixedly connected with the surface of the pressure relief plate 17.

[0044] When the air pressure in the installation chamber 3 rises and reaches a pressure sufficient to push the buffer frame 5 to displace and the deformation guide 1701 of the pressure relief plate 17 to deform enough to make the shearing bolt assembly fracture, the pressure reaches a second threshold value. The pressure uniformly acts on the inner surface of the pressure relief plate 17. In addition, before reaching the second threshold value, the prism-shaped guide portion only elastically deforms. When the pressure reaches and exceeds the second threshold value, the guide portion enters the plastic deformation stage, and the plate surface regularly bulges outward along the stress grooves 18. The deformation forces the screw rod 20 of the shearing bolt to bear a huge shearing force, and the screw rod 20 is neatly broken at the fracture inducing portion 22. At the moment of fracture of the bolt, the pressure relief plate 17 obtains an initial displacement, and then the buckle 1702 hooks the everted edge 19 of the buffer frame 5, forming a mechanical linkage to drive the entire pressure relief unit to open around the everted edge 19, realizing the second-stage directional complete pressure relief.

[0045] The implementation principle of the embodiment 1 of the application is that the grading pressure relief function of the safety cable branch box is realized based on a set of precise mechanical linkage logic. When the air pressure in a certain installation chamber 3 rises due to arc fault, the system responds in stages: Firstly, the air pressure acts on the buffer frame 5, when the pressure reaches the first threshold, the buffer frame 5 is pushed to overcome the resistance of the damper 12, the external atmospheric pressure and the combined force of the return spring, and slides outward along the guide groove 9 of the fixed frame 4. This process instantaneously increases the chamber volume, which is equivalent to physically buffering and absorbing the initial energy of the explosion, achieving the first-stage buffer pressure relief.

[0046] If the fault is slight, the pressure is thus released, and the buffer frame 5 can be automatically reset under the action of the spring and the external air pressure, and the system returns to normal.

[0047] Secondly, if the fault is serious, the air pressure continues to rise to the second threshold, and the pressure mainly acts on the prismatic deformation guide part 1701 of the pressure relief plate 17. The structure is guided by the stress groove 18 to undergo a controllable plastic bulging deformation, forcing the shear bolt to bear excessive shear stress in its preset V-shaped fracture induction part 22 and cause neat fracture.

[0048] The moment the bolt breaks, the pressure relief plate 17 moves outward under the drive of the remaining air pressure, and its buckled edge 1702 immediately hooks the outward turned edge 19 of the buffer frame 5, forming a rigid mechanical linkage. At this time, the buffer frame 5 has slid to the end of the stroke and formed a rigid abutment with the fixed frame 4, so the thrust of the pressure relief plate 17 is converted into a torque that drives the entire pressure relief unit (fixed frame 4, buffer frame 5, pressure relief plate 17) to rotate around the heavy hinge 6 rotation shaft 603, thereby completely opening the pressure relief channel and achieving the second-stage directional complete pressure relief.

[0049] The entire process realizes intelligent judgment and hierarchical disposal of fault pressure through pure mechanical structure, ensuring extreme safety while minimizing unnecessary downtime and damage. Embodiment 2

[0050] A safety cable branch box, with reference to Figure 8 、 Figure 9 The difference between the safety cable branch box and the embodiment 1 is that the bottom of the partition plate 2 is provided with a balance air channel 23 communicating with two adjacent installation chambers 3. A U-shaped partition block 24 made of elastic material is arranged in the balance air channel 23. The horizontal part of the partition block 24 is inserted into the balance air channel 23 and blocks the balance air channel 23, and the vertical ends of the partition block 24 extend into the two adjacent installation chambers 3, respectively. In addition, a gas guide groove 25 is formed on the horizontal part of the partition block 24, and the two ends of the partition block 24 abut against the surface of the corresponding partition plate 2, thereby blocking the gas guide groove 25.

[0051] In addition, the vertical ends of the partition block 24 are integrally formed with a pressure receiving plate 26, and when the air pressure in any installation chamber 3 rises, the corresponding pressure receiving plate 26 is pushed to make the U-shaped partition block 24 elastically deform, thereby opening the balance air channel 23 and the gas guide groove 25.

[0052] The implementation principle of the embodiment 2 of the present application is that the embodiment 3 adds a pressure balance mechanism between adjacent installation cavities 3 on the basis of the embodiment 1.

[0053] The principle is that when a certain installation cavity 3 has a fault and the air pressure abnormally rises but has not reached its own first pressure relief threshold, the pressure difference generated between the cavity and the adjacent cavity will act on the pressure plate 26 at one end of the U-shaped partition block 24.

[0054] The pressure plate 26 is forced to push the elastic U-shaped partition block 24 to deform, so that the air guide groove 25 of the horizontal part of the U-shaped partition block 24 is aligned with the balance air duct 23, thereby temporarily opening a limited pressure relief channel. Allow part of the gas in the high-pressure cavity to slowly flow into the adjacent low-pressure cavity, realize the preliminary balance of pressure and peak reduction.

[0055] This mechanism can actively inhibit the rapid accumulation of local pressure in the early stage of failure, sometimes can avoid triggering the action of the pressure relief device of the cavity, prevent the expansion of the failure; even if the pressure relief is still needed, it can reduce the strength and impact of the pressure relief.

[0056] When the pressure difference decreases, the U-shaped partition block 24 restores to its original state under its own elasticity, reseals the balance air duct 23, and ensures the air-tight independence of each cavity under normal conditions. This structure provides an additional passive systematic pressure protection level for large multi-cavity cable branch boxes, further enhancing the overall safety of the product.

[0057] The embodiments of the specific implementation are the preferred embodiments of the present application, but not limited to the protection scope of the present application, wherein the same parts are indicated by the same reference numerals. Therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A safety cable branch box, comprising a box body (1), characterized in that, The inner cavity of the box (1) is divided into multiple independent installation chambers (3) by partitions (2), and a graded pressure relief device is provided at the opening of the box (1) corresponding to each installation chamber (3); The graded pressure relief device includes: A fixed frame (4) is rotatably connected to the surface of the box (1) by a hinge (6) and is locked by a locking assembly (8); A buffer frame (5) is slidably connected to the fixed frame (4) by at least one guide buffer mechanism, so that the buffer frame (5) can move relative to the fixed frame (4) in a direction away from or close to the mounting chamber (3); A first sealing element (11) is provided between the fixed frame (4) and the buffer frame (5) to form a dynamic seal between them; The pressure relief plate (17) is fixedly connected to the buffer frame (5) by a shear bolt assembly. The pressure relief plate (17) has an outwardly protruding deformation guide (1701) on the side facing the mounting chamber (3). A second sealing element (27) is provided between the pressure relief plate (17) and the buffer frame (5); The buffer frame (5), the guide buffer mechanism, and the shear bolt assembly work together to form a two-stage pressure relief response mechanism for the rise in air pressure in the mounting chamber (3): when the air pressure rises to the first threshold, the buffer frame (5) is pushed to slide against the resistance of the guide buffer mechanism to expand the volume of the mounting chamber (3) and achieve the first stage of buffer pressure relief; when the air pressure continues to rise to a higher second threshold, the deformation guide part (1701) of the pressure relief plate (17) generates deformation sufficient to break the shear bolt assembly, the pressure relief plate (17) separates from the buffer frame (5) and opens around the hinge (6) to achieve the second stage of directional complete pressure relief.

2. The safety cable branch box according to claim 1, characterized in that: The pressure relief plate (17) has a buckle (1702) bent towards the buffer frame (5) on one side periphery; The buffer frame (5) is provided with an outward flange (19) corresponding to the position of the buckle (1702); In the initial state, there is a preset gap between the end of the buckle (1702) and the outer flange (19); the preset gap is less than the initial displacement of the pressure relief plate (17) relative to the buffer frame (5) at the moment the shear bolt assembly breaks, so that after the shear bolt assembly breaks, the pressure relief plate (17) moves outward by the preset gap, and the buckle (1702) hooks onto the outer flange (19) to form a mechanical linkage.

3. A safety cable branch box according to claim 1, characterized in that, The guiding buffer mechanism includes: A guide groove (9) is formed on the fixed frame (4); A guide member fixed to the buffer frame (5) and extending into the guide groove (9); An elastic element disposed within the guide groove (9) for providing a restoring elastic force to the buffer frame (5); The damper (12) has its cylinder fixed in the guide groove (9) and its piston rod connected to the buffer frame (5) to provide damping for the sliding of the buffer frame (5).

4. A safety cable branch box according to claim 3, characterized in that, The shear bolt assembly includes a screw (20) and a mounting nut (21); the screw (20) has a fracture induction section (22) with a reduced cross-sectional area; the mounting nut (21) presses and fixes the pressure relief plate (17) onto the buffer frame (5), so that when the pressure relief plate (17) is deformed by force, the buffer frame (5) forms a shearing action on the screw (20).

5. A safety cable branch box according to claim 4, characterized in that, The deformation guide (1701) is a convex frustum shape with stress grooves (18) radiating from the center to the periphery on its plate surface.

6. A safety cable branch box according to claim 3, characterized in that, The guide groove (9) is an annular groove, and the guide member is an annular guide post (10) adapted to the annular groove; the first sealing member (11) is disposed on the outer circumferential surface of the annular guide post (10) and slides and seals with the groove wall of the annular groove, thereby forming a sealed buffer air chamber between the fixed frame (4) and the buffer frame (5); the fixed frame (4) is provided with a one-way valve group communicating with the buffer air chamber for adjusting the air pressure in the buffer air chamber.

7. A safety cable branch box according to claim 6, characterized in that, The one-way valve assembly includes an intake one-way valve (14) and an exhaust one-way valve (15). Under normal conditions, the air pressure in the buffer chamber is lower than the external ambient air pressure. When the buffer frame (5) slides outward, the intake one-way valve (14) opens to replenish air into the buffer chamber. When the buffer frame (5) is reset under the action of the elastic element, the exhaust one-way valve (15) opens to discharge excess gas.

8. A safety cable branch box according to claim 7, characterized in that, The annular guide post (10) is provided with a visual indicator mark (16) that moves synchronously with it, for observing the sliding state of the buffer frame (5) from the outside.

9. A safety cable branch box according to claim 1, characterized in that, The bottom of the partition (2) is provided with a balance air passage (23) that connects two adjacent installation chambers (3). The balance air passage (23) is provided with a pressure-responsive sealing structure. The pressure-responsive sealing structure closes the balance air passage (23) when the pressure difference between adjacent chambers is less than a set value, and opens to balance the pressure when the pressure difference exceeds the set value.

10. A safety cable branch box according to claim 9, characterized in that, The pressure-responsive sealing structure includes a U-shaped partition (24) made of elastic material, the middle part of which is disposed in the balance airway (23), and its two ends extend into two adjacent installation chambers (3) to form pressure plates (26); when the air pressure in any installation chamber (3) increases, the corresponding pressure plate (26) is pushed, causing the U-shaped partition (24) to elastically deform, thereby opening the balance airway (23).

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