Flame retardant device for diagonal cable capable of bidirectional expansion upon heat, and its mounting method.

Abstract

The present invention relates to a bidirectionally expandable stay cable flame retardant device and its installation method. The device includes a fire retardant ring 1 and a positioning jig 2. The fire retardant ring is fixed to the surface of the stay cable body 7 using the positioning jig. The fire retardant ring covers the stay cable body. When exposed to heat, the fire retardant ring expands inward to encase the stay cable body and expands outward to insulate the stay cable body on both sides of the fire retardant ring. The stay cable body where the fire retardant ring is installed is wrapped with weather-resistant fire tape, and the fire retardant ring is installed outside the fire retardant tape. The fire retardant ring includes a fire retardant ring casing 9 and a fire retardant core 10, which is installed inside the fire retardant ring casing. This application uses a bidirectionally expandable fire retardant core as the central component of the fire retardant. Taking advantage of its thermal expansion properties, the fire retardant core envelops the cable body inward and expands outward to insulate the cable body on both sides, preventing the spread of fire.

Description

Technical Field

[0001] The present invention relates to a flame-proof device for diagonal cables, specifically to a flame-proof device based on the principle of expansion when heated and its installation method.

Background Art

[0002] During the service life of a large cable-stayed bridge, smoke appeared and a fire occurred at the end position near the main tower of the diagonal cable of the 2# on the east side of a certain bridge. When relevant agencies such as construction, design, construction, fire protection, and traffic police rushed to the scene in the first time for disposal, the 2# diagonal cable broke and fell onto the bridge deck, but no casualties or vehicle damages occurred. According to the first-stage analysis, the cause of the fire was that the wire connector of the lighting circuit of the 2# diagonal cable was short-circuited, and a part of the diagonal cable caught fire and burned. Due to the absence of a flame-proof device, the fire spread along the diagonal cable sheath and the cable body, and some cable support members that were relatively sensitive to temperature were deformed and burned out.

[0003] For the diagonal cables that are relatively widely applied in the field of cable-stayed bridges, there are mainly two types of systems: parallel wire diagonal cables and strand diagonal cables. The parallel wire diagonal cable arranges high-strength zinc-plated or zinc-aluminum alloy wires tightly in a regular hexagon or a defective regular hexagon, twists them slightly counterclockwise at a twist angle of 2° - 4°, then winds a high-strength polyester fiber tape clockwise, and directly extrudes a high-density polyethylene (PE) sheath outside the wire for protection, and is combined with a cold-forged bolt head anchor. In the free area of the parallel wire diagonal cable, a two-layer protection system of wire zinc-plated aluminum alloy + two-layer hot extrusion HDPE jacket is adopted.

[0004] The stranded diagonal cable is constructed by hot-extruding a polyethylene (PE) sheath onto a single strand to form a bundle of strands. The outer layer of the entire bundle is a double-layer synchronously extruded high-density polyethylene (HDPE) protective sleeve, forming a free-stretching area. A clip-type tension end anchor (including a nut) and a fixed end anchor (without a nut) are provided at both ends. The free area of ​​the stranded diagonal cable employs a four-layer protective system consisting of a zinc-plated / epoxy layer on the strand + oily wax + hot-extruded PE sheath + HDPE jacket.

[0005] In the two types of diagonal cable structures described above, the wire, which is the main load-bearing member, has a relatively high melting point, so short-term heating only reduces its strength and elastic modulus, and the possibility of breakage is relatively low. However, the high-density polyethylene sheath protecting the diagonal cable wire has a considerably low softening point, melting point, and ignition point. It softens at around 120°C, melts at around 200°C, and burns at around 342°C. Therefore, if a fire occurs in the diagonal cable, the high-density polyethylene sheath will soften and melt first, and once it burns to a certain extent, the high-density sheath will burn. When it burns, the flames will spread along the polyethylene sheath of the diagonal cable, causing the high-density polyethylene sheath to melt and deform due to the flames and high temperature, and if it burns through and creates a hole, the flames will further expand through the hole, increasing the area of ​​fire damage in the diagonal cable. In addition, in strand diagonal cable systems, there is a large amount of oil on the cable body and anchor fixing points, and since oil is a combustion-supporting material, it accelerates the spread of the fire. Therefore, preventing and blocking the spread of flames on the polyethylene sheath and the cable itself of the diagonal bracing cable is extremely important for fire protection of the diagonal bracing cable. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] (none) [Overview of the Initiative]

[0007] In contrast to the conventional operation of diagonal bracing cables, the present invention presents a diagonal bracing cable fire retardant device and its installation method that can be attached to the diagonal bracing cable to prevent the spread of fire, and which enables bidirectional expansion through preheating (heat absorption).

[0008] The technical method employed in the present invention is as follows: A diagonal cable flame retardant device capable of bidirectional expansion by preheating (heat reception) includes a flame retardant ring and a positioning jig, wherein the flame retardant ring is fixed to the surface of the diagonal cable body by the positioning jig, the flame retardant ring covers the diagonal cable body, and when the flame retardant ring receives heat, it expands inward to enclose the diagonal cable body and expands outward to block the diagonal cable body on both sides of the flame retardant ring.

[0009] In one embodiment of the present invention, the flame-retardant ring has an integrated structure, and the diagonal cable body passes through the flame-retardant ring, or the flame-retardant ring has a half-structure and is installed so as to wrap around the diagonal cable body.

[0010] In one embodiment of the present invention, a weather-resistant fireproof tape is wrapped around the main body portion of the diagonal cable on which the flame-retardant ring is installed, and the flame-retardant ring is installed further outside of the fireproof tape. Since the flame-retardant ring does not come into direct contact with the cable body, it is possible to avoid pressing on and damaging the high-density polyethylene layer on the surface of the cable body.

[0011] In one embodiment of the present invention, the flame-retardant ring includes a flame-retardant ring casing, a flame-retardant core, and a buckle, wherein the flame-retardant core is installed inside the flame-retardant ring casing, and the buckle is fitted to the outside of the flame-retardant ring casing. The flame-retardant ring casing is used to provide daily protection for the flame-retardant core, reducing the amount of environmental interference the core is exposed to. The flame-retardant ring casing is preferably made of high-density polyethylene.

[0012] In one embodiment of the present invention, the flame-retardant core material has an annular structure, the flame-retardant ring casing has a hollow annular structure, the flame-retardant ring casing includes a flame-retardant ring cylinder, a flame-retardant ring upper cover plate, and a flame-retardant ring lower cover plate, the flame-retardant core material is installed inside the flame-retardant ring cylinder, the flame-retardant ring upper cover plate and the flame-retardant ring lower cover plate are installed at the upper and lower ends of the flame-retardant ring cylinder, and the flame-retardant core material is fixed inside the flame-retardant ring cylinder.

[0013] In one embodiment of the present invention, the flame-retardant ring casing is made of high-density polyethylene material, has a thickness of no less than 3 mm, and the inner diameter of the flame-retardant ring casing is 1 to 3 mm larger than the outer diameter of the diagonal cable body. The settings for the inner diameter D1, outer diameter D2, and height H of the above-mentioned flame-retardant core material shall be as shown in the table below.

[0014] [Table 1]

[0015] In one embodiment of the present invention, a positioning groove is machined into the surface of the flame-retardant ring casing, and the positioning groove is used to install the buckle, which integrally fixes the flame-retardant ring casing with a half-type structure. Since the flame-retardant ring casing employs a half-type structure, it is useful for installing the flame-retardant ring, adjusting the mounting position of the flame-retardant ring on the cable body, and for subsequent maintenance and replacement.

[0016] In one embodiment of the present invention, the positioning jig is installed at the lower end of a flame-retardant ring, the bottom of the flame-retardant ring is supported on the positioning jig, the positioning jig has a half structure and encloses the outside of the diagonal cable body, a silicone rubber with a thickness of 5 mm to 10 mm is installed in the inner hole of the positioning jig, and the silicone rubber encloses the outside of the diagonal cable body. By utilizing the contact between the silicone rubber and the cable body, the polyethylene sheath layer on the surface of the cable body can be protected on a daily basis, and damage to the surface of the cable body can be prevented by the installation of the positioning jig.

[0017] In one embodiment of the present invention, a connecting hole is provided on the surface of the positioning jig, and the positioning jig and the flame-retardant ring are connected by installing a connecting member in the connecting hole, or an external position limit is formed on the flame-retardant ring by installing a position limiting member in the connecting hole. This ensures reliable support and positioning of the positioning jig relative to the flame-retardant ring.

[0018] Fires in diagonal bracing cables are mainly caused by the burning of vehicles traveling on the bridge deck or by construction work at tower ends and bridge ends. Therefore, in addition to pre-burying pipes at bridge ends, fire-resistant devices that enable bidirectional expansion (expanding both inward and outward) through preheating (heat absorption) are installed in areas affected by flames during vehicle fires and at important locations such as tower ends. This creates an isolation at the point of fire in the diagonal bracing cable, preventing the flames from spreading along the surface of the cable itself and preventing further damage from the flames spreading along the diagonal bracing cable after the high-density polyethylene sheath has burned.

[0019] The fire-retardant device designed in this invention has a simple structure, is easy to attach to the cable body, and is not affected by the structure of the diagonal cable itself, making it convenient for widespread application. This invention uses a bidirectional expandable fire-retardant core material as the central fire-retardant component. By utilizing its property of expanding in response to heat, it envelops the cable body inward to prevent the spread of flames and expands outward to block the cable body on both sides, thereby preventing the spread of fire.

[0020] The inventors of this application further desire that the flame-extinguishing function be achieved through the structural design of the flame-retardant ring and positioning jig, and the relevant embodiments are as follows.

[0021] A flame-proof device, including a flame-proof ring and a clamping jig. The flame-proof ring includes an inner sleeve and an outer sleeve. A double layer is provided inside the outer sleeve, and a fire extinguishing liquid is filled inside the double layer. The inner sleeve is installed slidably inside the outer sleeve. Barrier edges are provided at both the outer edge of the top end of the inner sleeve and the inner edge of the bottom end of the outer sleeve. A cavity is formed between the inner sleeve and the outer sleeve, and a low-melting-point colloid is provided at the bottom inside the cavity. The inner sleeve and the outer sleeve are fixed by the low-melting-point colloid. A liquid outlet communicating with the double layer is provided at the lower part inside the outer sleeve. The outer end face of the liquid outlet is fitted with the outer wall of the inner sleeve, and a low-melting-point seal is fixed at the inner end of the liquid outlet. A core material ring with a C-shaped cross-section is fixed at the lower part inside the inner sleeve, and a flame-proof core material is provided inside the core material ring. The flame-proof core material is fixed inside the core material ring with a fireproof tape.

[0022] The inner sleeve consists of two symmetrically installed inner half sleeves. First clamping grooves are provided on the outer sides of the bottom ends of the two inner half sleeves, and the bottom end between the two inner half sleeves is fixed by the first clamping groove and the first buckle.

[0023] The outer sleeve consists of two symmetrically installed outer half sleeves. Second clamping grooves are provided on the circumferential side surfaces of the two outer half sleeves, and the two outer half sleeves are fixed by the second clamping groove and the second buckle.

[0024] An end sleeve is provided at the top end of the outer sleeve, and a locking edge is provided on the circumferential side surface of the end sleeve. The clamping jig includes a set of symmetrically installed half-ring bodies. The two half-ring bodies are connected to each other by clamping bolts, and a locking groove engaging with the locking edge is fixed at the lower part inside the half-ring body.

[0025] The flame-proof ring and the clamping jig are covered outside the diagonal member cable body. Silicon rubber is provided inside the half-ring body. The inner wall of the silicon rubber is fitted with the outer wall of the diagonal member cable body, and an avoidance gap is formed between the inner side of the core material ring and the outer wall of the diagonal member cable body.

[0026] An avoidance port is opened at the top end of the inner sleeve, and the avoidance port faces the position of the liquid outlet. Guide ribs are provided on the circumferential side surface of the inner sleeve, a notch is provided on the barrier edge, and the guide ribs slide along the guide groove.

[0027] The above flameproof device having a fire extinguishing function has the following beneficial effects. 1. In the present invention, by designing the expandable inner sleeve and outer sleeve as a flameproof ring, when combustion spreads to a predetermined position, the inner sleeve spontaneously extends, and at the same time, in combination with the design of the flameproof core material that can expand upon receiving heat, the combustion spread point can be completely covered within the inner sleeve. By performing flameproof blocking below the combustion spread point with the flameproof core material, fire extinguishing operation is performed on the space between the inner sleeve and the diagonal member cable body by the design of the fire extinguishing liquid in the outer sleeve, and fire extinguishing type blocking is performed above the combustion spread point, blocking the spread of the flame along the surface of the cable body, preventing the flame after the high-density polyethylene sheath burns from spreading along the diagonal member cable body and causing further disasters.

[0028] 2. In the present invention, due to the design of the flameproof core material, it can expand when preheated (receiving heat), and by pressing the polyethylene sheath that has already softened or melted when receiving heat inward, blocking can be performed below the combustion spread point. At the same time, the space between the inner sleeve and the diagonal member cable body can be blocked, and the combustion spread point can be completely limited within the inner sleeve. Therefore, not only can the air for combustion be blocked, but also the space for the fire extinguishing liquid can be provided, improving the flameproof effect of the flameproof ring.

[0029] 3. The inner sleeve and outer sleeve of the present invention are connected and fixed via a low-melting-point colloid. The low-melting-point colloid corresponds to an identification function when the fire spreads to a predetermined position. When the fire spreads to a position close to the flameproof ring, the low-melting-point colloid spontaneously melts, realizing the spontaneous extension of the inner sleeve to cover the spread point.

[0030] 4. The present invention seals the liquid outlet with a low-melting-point seal. The low-melting-point seal acts as a switch when a fire spreads to a predetermined location. When the fire spreads close to the flame-retardant ring, the low-melting-point seal melts spontaneously, opening the liquid outlet.

[0031] 5. Since the present invention is designed with the inner sleeve, outer sleeve, and tightening jig as two symmetrically installed structural members, they can be quickly attached to the diagonal cable body, which is useful for the installation, removal, maintenance, and replacement of the fire-retardant device, and is also easy for workers to operate.

[0032] Of course, it is not necessary to achieve all of the above advantages simultaneously in order to implement any of the products of the present invention. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 is a schematic diagram of the installation of the diagonal cable flame retardant device in Embodiment 1 of the present invention. [Figure 2] Figure 2 is a central cross-sectional view of the flame-retardant device in Embodiment 1 of the present invention. [Figure 3] Figure 3 is a central cross-sectional view of the flame-retardant ring cylinder in Embodiment 1 of the present invention. [Figure 4] Figure 4 is a schematic diagram of the structure of the upper cover plate or lower cover plate of the flame-retardant ring in Embodiment 1 of the present invention. [Figure 5] Figure 5 is a schematic diagram of the structure of the flame-retardant ring casing in Embodiment 1 of the present invention. [Figure 6] Figure 6 is a central cross-sectional view of the fire-retardant device after assembly in Embodiment 1 of this application. [Figure 7] Figure 7 is a schematic diagram of the installation of the flame retardant device in Embodiment 1 of the present invention. [Figure 8] Figure 8 is a schematic diagram of the positioning jig structure in Embodiment 1 of this application. (Explanations of reference numerals in Figures 1-8 are moved to the end of this specification.) [Figure 9] Figure 9 is a schematic diagram of the structure of the flame-retardant device in Embodiment 2 of the present invention. [Figure 10] Figure 10 is a cross-sectional view of the structure of the fire-retardant device in the normal state in Embodiment 2 of this application. [Figure 11] Figure 11 is a cross-sectional view of the flame-retardant device in flame-retardant mode in Embodiment 2 of this application. (Explanations of reference numerals in Figures 9-11 are moved to the end of this specification.) [Modes for carrying out the invention]

[0034] The present invention is described in more detail below in conjunction with the drawings, but the embodiments described are illustrative and intended for interpretation of the invention, and should not be understood as limitations to the invention. The textual descriptions in these embodiments correspond to the drawings, and the descriptions of directions are also based on the drawings, and should not be understood as limitations to the scope of protection of the present invention.

[0035] [Example 1] Figures 1-8As shown, the diagonal cable fire retardant device includes a fire retardant ring 1 and a positioning jig 2, the fire retardant ring 1 including a fire retardant ring casing 9, a fire retardant core material 10 and a buckle 11. The principle by which the fire retardant device can prevent fire from spreading along the high-density polyethylene sheath is as follows: When a fire breaks out in part of the diagonal cable body, the polyethylene flame-retardant ring casing of the flame-retardant device first softens (around 120°C), melts (around 180°C), and burns (345°C). The flame-retardant core material of the flame-retardant device, which is attached to the outside of the polyethylene sheath of the diagonal cable, is heated by the flame and high temperature, causing a chemical reaction that rapidly expands it. This expansion forms a dense carbonized layer with a certain strength, which expands outward to form a large flame-retardant ring. Simultaneously, it presses the softened or melted polyethylene sheath inward, sealing the holes formed in the polyethylene sheath of the diagonal cable due to the heat and softening or burning within a relatively short time. This prevents the flame from spreading along the polyethylene sheath of the diagonal cable to the tower end or bridge end, thus preventing the spread of the fire and eliminating the problem of premature failure of the diagonal cable's support, especially at the anchor points, caused by the spread of fire in part of the diagonal cable body. The flame-retardant ring can be either a one-piece or half-piece type. When using an integrated fire-retardant device, pull the cable itself in before driving anchors into the diagonal cable.

[0036] The technical requirements for the diagonal cable flame retardant device and its associated components are as follows: 1. The flame-retardant ring casing of the flame-retardant device is made of high-density polyethylene and has a thickness of no less than 3 mm. The inner diameter of the casing (flame-retardant ring casing) is 1 to 3 mm larger than the outer diameter of the polyethylene sheath of the diagonal cable body. When the polyethylene sheath of the diagonal cable burns, the flame-retardant ring casing melts first, ensuring that the flame-retardant core material can rapidly expand 20 to 40 times inward and outward simultaneously, forming a huge flame-retardant ring and effectively preventing the fire from spreading along the cable body. The flame-retardant ring casing is made of high-density polyethylene material with relatively high aging resistance, and the performance parameters of this polyethylene material are as shown in the table below.

[0037] [Table 2]

[0038] The processing method for high-density polyethylene casing (flame-retardant ring casing) is as follows. 1) A high-density polyethylene sleeve is hot-extruded based on the design dimensions, and the material is cut to the required height to form a cylindrical body for the high-density polyethylene casing of the diagonal cable flame retardant device. Two positioning grooves, 10-20 mm wide and 1-2 mm deep, are machined into the cylindrical body, and the cylindrical body is cut open from the center line. 2) Based on the design requirements, the upper and lower cover plates of the high-density polyethylene casing of the flame retardant device are processed and cut along the center line to form two semicircular rings. 3) Using a hot melt welding gun or an ultrasonic welding gun specifically for polyethylene, the upper and lower cover plates and the cylindrical body of the high-density polyethylene casing are welded together to form a high-density polyethylene casing for the flame retardant device, i.e., a flame retardant ring casing.

[0039] 2. The flame-retardant core material of the flame-retardant device may be a chemically expanding flame retardant or a physically expanding flame retardant.

[0040] Here, chemically expanding flame retardants consist of three parts: an acid source (dehydrating agent), a carbon source (carbon generating agent), and a gas source (foaming agent). Of these, the acid source is mainly phosphoryl chloride phosphate, ammonium polyphosphate, etc. The carbon source is mainly a polyhydroxy compound or carbohydrate with a relatively high carbon content, and is the base for forming the foamed carbonized layer. It is one of several polyhydroxy compounds with a relatively high carbon content, such as phenolic resin, polyamide, erythritol, maltose, and starch. The gas source is also called the foaming source. Common foaming sources include melamine, dicyandiamide, ammonium polyphosphate, and urea. The above gas source materials can release a large amount of flame-retardant gas when decomposed under heat, and the foaming effect is exerted by the expansion of the formed carbonized layer. In summary, the flame retardant mechanism of chemically expanding flame retardants is as follows: When heated, the acid source decomposes to produce a dehydrating agent, which can form an ester together with the carbon generating agent. The ester then undergoes dehydration and crosslinking to form carbon, and at the same time, the foaming agent releases a large amount of gas, which helps the carbon layer expand. The thick carbon layer increases the temperature gradient between the polymer surface and the carbon layer surface, lowering the polymer surface temperature considerably below the flame temperature. This reduces the possibility of further polymer decomposition and release of flammable gases, while simultaneously blocking the entry of external oxygen, thus providing flame retardancy to the polymer for a considerably long period of time.

[0041] The core material of the flame retardant can also be made of a physically expandable graphite material. At high temperatures, the expandable graphite rapidly expands, extinguishing the flame, and at the same time, the generated expanded graphite material covers the surface of the substrate, blocking the radiation of thermal energy and contact with oxygen. The acidic groups inside the double layer are also released during expansion, promoting the carbonization of the substrate, so good effects can be obtained with various flame retardant methods.

[0042] The thermal expansion volume of the flame-retardant core material in a flame-retardant device can reach 20 to 40 times its original volume.

[0043] The flame-retardant core material of the flame-retardant device is a semi-ring shape, and the relevant dimensions of this ring shape are determined by the table below.

[0044] [Table 3]

[0045] A schematic diagram of the fire-retardant device after assembly is shown in Figure 6.

[0046] 3. To prevent the flame retardant device housing and flame retardant core material from colliding with or rubbing against the high-density polyethylene sheath during operation of the diagonal cable, a weather-resistant fireproof tape (e.g., polyvinyl fluoride tape) with a thickness of 3 to 6 mm is wrapped around the location where the flame retardant device is to be installed.

[0047] 4. To prevent the flame-retardant ring from falling off, a flange with holes is installed on the flame-retardant ring casing and connected to a lower positioning jig to position the flame-retardant ring and prevent it from slipping and falling off during the operation of the cable-stayed bridge. The positioning jig for the half-type flame-retardant device may be installed before the anchors are driven into the cable members, or after the anchors have been driven in or after the cable members have been erected.

[0048] 5. A positioning jig 2 is installed at the lower end of the flame retardant device. The positioning jig employs a half-type structure, connecting the two components with screws 13. To protect the polyethylene sheath of the diagonal cable from damage by the jig, a 5mm to 10mm thick silicone rubber 12 is installed in the inner hole of the jig. The Shore hardness is 50 to 60.

[0049] [Example 2] As shown in Figures 9-11, this embodiment relates to a fire suppression device for extinguishing flames, and includes a fire suppression ring and a tightening jig 1. The fire suppression ring includes an inner sleeve 2 and an outer sleeve 3. A double layer 301 is provided inside the outer sleeve 3, and the double layer 301 is filled with a fire suppression liquid (clean water or fine sand). The inner sleeve 2 is slidably installed inside the outer sleeve 3, and barrier edges 201 are provided on the outer edge of the top end of the inner sleeve 2 and the inner edge of the bottom end of the outer sleeve 3. A cavity 202 is formed between the inner sleeve 2 and the outer sleeve 3, and a low melting point colloid 203 is provided at the bottom of the cavity 202. The inner sleeve 2 and outer sleeve 3 are fixed together by a low-melting-point colloid 203. A liquid outlet 302 communicating with a double layer 301 is provided on the lower inner side of the outer sleeve 3. The outer end surface of the liquid outlet 302 is bonded to the outer wall of the inner sleeve 2. A low-melting-point seal 303 is fixed to the inner end of the liquid outlet 302. A core material ring 204 with a C-shaped cross-section is fixed to the lower part inside the inner sleeve 2. A flame-retardant core material 205 is provided inside the core material ring 204, and the flame-retardant core material 205 is fixed inside the core material ring 204 by fire-resistant tape 206 (for example, polyvinyl fluoride tape).

[0050] The inner sleeve 2 consists of two symmetrically positioned inner half sleeves 207, each having a first tightening groove 208 on the outside of its bottom end, and the bottom end between the two inner half sleeves 207 is fixed by the first tightening groove 208 and a first buckle (209). A relief opening 210 is provided at the top end of the inner sleeve 2, and the relief opening 210 is opposite the position of the liquid outlet 302. Guide ribs are provided on the circumferential surface of the inner sleeve 2, and notches are provided on the barrier edge 201, and the guide ribs slide along the guide grooves.

[0051] The outer sleeve 3 consists of two symmetrically positioned outer half sleeves 306, each having a second tightening groove 307 on its circumferential surface, and the two outer half sleeves 306 are fixed together by the second tightening groove 307 and a second buckle 308. An end sleeve 304 is provided at the top of the outer sleeve 3, and a locking edge 305 is provided on the circumferential surface of the end sleeve 304. The tightening jig 1 includes a pair of symmetrically positioned half ring bodies 101, the two half ring bodies 101 are connected to each other by tightening bolts, and a locking groove 102 that engages with the locking edge 305 is fixed to the lower part of each half ring body 101.

[0052] The flame-retardant ring and the fastening jig 1 are fitted to the outside of the diagonal cable body 4, a silicone rubber pad 103 is provided inside the semi-ring body 101, the inner wall of the silicone rubber pad 103 is bonded to the outer wall of the diagonal cable body 4, and a clearance gap is formed between the inside of the core ring 204 and the outer wall of the diagonal cable body 4.

[0053] The operating principle of the flame retardant device in this embodiment is as follows: If a fire breaks out in the sheath layer on the surface of the diagonal cable body 4 and spreads to a location close to this device, the low-melting-point colloid 203 and low-melting-point seal 303 will melt as the combustion temperature increases. The low-melting-point seal 303 is a sealing point formed by the low-melting-point colloid. The low-melting-point colloid melts in the high-temperature environment caused by the flame.

[0054] The melting of the low-melting-point colloid 203 releases the fixation between the inner sleeve 2 and the outer sleeve 3, causing the inner sleeve 2 to descend by gravity. At this time, the point of combustion is inside the inner sleeve 2 and above the flame-retardant core material 205, so the point of combustion is enclosed within the inner sleeve 2. The fire-resistant tape 206 melts due to the high temperature, and the flame-retardant core material 205 expands due to the heat. The inside of the expanded flame-retardant core material 205 encloses the outside of the already burning cable body below the point of combustion.

[0055] The melting of the low-melting-point seal 303 corresponds to the opening of the liquid outlet 302. As the inner sleeve 2 slides downward along the outer sleeve 3, the end of the liquid outlet 302 adheres to the outer wall of the inner sleeve 2, continuing to seal to a certain extent. After the inner sleeve 2 has completely fallen, the liquid outlet 302 is exposed to the outside, and the fire extinguishing liquid in the double layer 301 is discharged by gravity into the gap between the inner sleeve 2 and the diagonal cable body 4. The bottom of the gap is then sealed by the expanded flame-retardant core material 205, thus extinguishing the combustion point that remains inside the inner sleeve 2 and directly blocking the spread of the combustion point. [Explanation of Symbols]

[0056] In Figures 1-8, 1 is a flame-retardant ring, 2 is a positioning jig, 201 is a connection hole, 3 is a diagonal cable bridge end rain cover, 4 is a diagonal cable bridge end pre-buried pipe, 5 is a white high-density polyethylene sheath, 6 is a black high-density polyethylene sheath, 7 is a diagonal cable wire bundle, 8 is weather-resistant fire-resistant tape, 9 is a flame-retardant ring casing, 10 is a flame-retardant core material, 11 is a buckle, 12 is silicone rubber, and 13 is a screw.

[0057] In Figures 9-11, 1 is a tightening jig, 2 is an inner sleeve, 3 is an outer sleeve, 4 is the diagonal cable body, 101 is a half-ring body, 102 is a locking groove, 103 is a silicone rubber pad, 201 is a barrier edge, 202 is a cavity, 203 is a low-melting-point colloid, 204 is a core ring, 205 is a flame-retardant core material, 206 is a fire-resistant tape, 207 is an inner half sleeve, 208 is the first tightening groove, 209 is the first buckle, 210 is a bypass opening, 301 is a double layer, 302 is a liquid outlet, 303 is a low-melting-point seal, 304 is an end sleeve, 305 is a locking edge, 306 is an outer half sleeve, 307 is the second tightening groove, and 308 is the second buckle.

Claims

1. A flame retardant device for diagonal cable capable of bidirectional expansion when heated, comprising a flame retardant ring and a positioning jig, wherein the flame retardant ring is fixed to the surface of the diagonal cable body by the positioning jig, the flame retardant ring covers the diagonal cable body, and when heated, the flame retardant ring expands inward to enclose the diagonal cable body and expands outward to block the diagonal cable body on both sides of the flame retardant ring, in a flame retardant device for diagonal cable capable of bidirectional expansion when heated, The flame retardant ring comprises a flame retardant ring casing, a flame retardant core material, and a buckle, wherein the flame retardant core material is installed inside the flame retardant ring casing, and the buckle is fitted to the outside of the flame retardant ring casing, and the flame retardant device for diagonal cable capable of bidirectional expansion when exposed to heat.

2. The flame retardant core material has an annular structure, the flame retardant ring casing has a hollow annular structure, the flame retardant ring casing includes a flame retardant ring cylinder, a flame retardant ring upper cover plate, and a flame retardant ring lower cover plate, the flame retardant core material is installed inside the flame retardant ring cylinder, the flame retardant ring upper cover plate and the flame retardant ring lower cover plate are installed at the upper and lower ends of the flame retardant ring cylinder, respectively, and a packing is installed at the joint, and the flame retardant core material is fixed inside the flame retardant ring cylinder, characterized in that a diagonal member cable flame retardant device capable of bidirectional expansion when subjected to heat is as described in claim 1.

3. The aforementioned flame-retardant ring casing is made of high-density polyethylene material, has a thickness of no less than 3 mm, and the inner diameter of the flame-retardant ring casing is 1 to 3 mm larger than the outer diameter of the diagonal cable body. The settings for the inner diameter D1, outer diameter D2, and height H of the aforementioned flame-retardant core material are shown in the table below. Table 1 A flame retardant device for diagonal cable that can achieve bidirectional expansion when subjected to heat, as described in claim 1, characterized by referring to the present invention.

4. The flame retardant cable flame retardant device according to claim 1, characterized in that a positioning groove is machined on the surface of the flame retardant ring casing, the positioning groove is used to install the buckle, and the buckle integrally fixes the flame retardant ring casing of the half-type structure, thereby enabling bidirectional expansion when exposed to heat.

5. The positioning jig is installed at the lower end of the flame retardant ring, the bottom of the flame retardant ring is supported on the positioning jig, the positioning jig has a half structure and encloses the outside of the diagonal cable body, a silicone rubber with a thickness of 5 mm to 10 mm is installed in the inner hole of the positioning jig, and the silicone rubber encloses the outside of the diagonal cable body, characterized in that the diagonal cable flame retardant device according to claim 1 is capable of bidirectional expansion when exposed to heat.

6. The flame retardant device for diagonal cable that can achieve bidirectional expansion when exposed to heat, as described in claim 5, characterized in that a connection hole is provided on the surface of the positioning jig, the positioning jig is connected to the flame retardant ring by installing a connecting member in the connection hole, or an external position limit is formed relative to the flame retardant ring by installing a position limiting member in the connection hole.

7. A flame retardant device for diagonal cable capable of bidirectional expansion when heated, comprising a flame retardant ring and a positioning jig, wherein the flame retardant ring is fixed to the surface of the diagonal cable body by the positioning jig, the flame retardant ring covers the diagonal cable body, and when heated, the flame retardant ring expands inward to enclose the diagonal cable body and expands outward to block the diagonal cable body on both sides of the flame retardant ring, in a flame retardant device for diagonal cable capable of bidirectional expansion when heated, The positioning jig is a clamping jig, the flame retardant ring includes an inner sleeve and an outer sleeve, a double layer is provided inside the outer sleeve, the double layer is filled with fire extinguishing liquid, the inner sleeve is slidably installed inside the outer sleeve, barrier edges are provided on the outer edge of the top end of the inner sleeve and the inner edge of the bottom end of the outer sleeve, a cavity is formed between the inner sleeve and the outer sleeve, a low melting point colloid is provided at the bottom of the cavity, the inner sleeve and outer sleeve are fixed by the low melting point colloid, a liquid outlet communicating with the double layer is provided on the lower inside of the outer sleeve, the outer end surface of the liquid outlet is bonded to the outer wall of the inner sleeve, a low melting point seal is fixed to the inner end of the liquid outlet, a core material ring with a C-shaped cross-section is fixed inside the lower part of the inner sleeve, a flame retardant core material is provided inside the core material ring, and the flame retardant core material is fixed inside the core material ring with fire-resistant tape, characterized in that bidirectional expansion is achievable when heated.

Images