Stay cable fire-stopping device capable of bidirectional expansion when exposed to heat and installation method therefor

Abstract

A stay cable fire-stopping device capable of bidirectional expansion when exposed to heat. The fire-stopping device comprises a fire-stopping ring and a positioning clamp (2). The fire-stopping ring is fixedly disposed on the surface of a stay cable body (4) by means of the positioning clamp (2), and wraps around the stay cable body (4). When exposed to heat, the fire-stopping ring expands inwards to tightly hold the stay cable body (4), and expands outwards to isolate portions of the stay cable body (4) on two sides of the fire-stopping ring. A weather-resistant fireproof tape (206) is wound around the stay cable body (4) at the location where the fire-stopping ring is disposed, and the fire-stopping ring is arranged outside the fireproof tape (206). The fire-stopping ring comprises a fire-stopping ring outer shell (9) and a fire-stopping core material (10), and the fire-stopping core material (10) is disposed inside the fire-stopping ring outer shell (9). The device uses a bidirectionally expanding fire-stopping core material as the core component for fire prevention. By virtue of its thermal expansion property, the core material, when exposed to heat, expands inwards to tightly hold the cable body and expands outwards to isolate portions of the cable body on two sides, thereby stopping fire from spreading.

Description

A stay cable fire arrester capable of achieving bidirectional expansion upon heating and its installation method Technical Field

[0001] The invention relates to a fire-blocking device for a stay cable, in particular to a fire-blocking device based on the principle of thermal expansion and an installation method thereof. Background Art

[0002] During the service of a cable-stayed bridge, smoke and fire broke out on the No. 2 cable on the east half of a bridge, near the main tower. Construction, design, construction, firefighting, and traffic police personnel responded immediately to the scene. Cable No. 2 broke and fell onto the bridge deck, causing no casualties or vehicle damage. Preliminary analysis indicates the fire was caused by a short circuit in the lighting wiring connector of cable No. 2, which caused a localized fire in the cable. Due to the lack of a fire arrester, the flames spread along the cable jacket and cable body, causing deformation and fracture of some temperature-sensitive cable-bearing components.

[0003] The two main types of cables commonly used in cable-stayed bridges are parallel steel wire cables and stranded steel wire cables. Parallel steel wire cables consist of high-strength galvanized or zinc-aluminum alloy steel wires tightly arranged in a regular hexagon or a partially regular hexagonal pattern. These cables are lightly twisted left-handed at a twist angle of 2° to 4° and then wrapped with a high-strength polyester fiber tape in a right-hand twist. High-density polyethylene (PE) sheathing is applied directly to the steel wires for protection, and cold-cast head anchors are used. The free end of parallel steel wire cables utilizes a dual-layer protection system: galvanized aluminum alloy steel wires and a double-layer, hot-extruded HDPE jacket.

[0004] The steel strand cable is composed of a single strand of steel wire wrapped in a hot-extruded polyethylene (PE) sheath. The entire cable bundle is covered with a double-layer, synchronously extruded high-density polyethylene (HDPE) protective casing, forming a free-extension section. Each end is equipped with a single clip-type tensioning anchor (with nut) and a fixed anchor (without nut). The free section of the steel strand cable utilizes a four-layer protection system: a galvanized / epoxy coating on the steel strand, an oil-based wax coating, a hot-extruded PE sheath on the steel strand, and an HDPE outer sheath.

[0005] In both of the above-mentioned cable-stayed structures, the steel wire, the main load-bearing component, has a high melting point. Short-term exposure to heat will only reduce its strength and elastic modulus, making fracture unlikely. However, the high-density polyethylene (HDPE) sheath protecting the cable's steel wire has relatively low softening, melting, and ignition points. It softens at around 120°C, melts at around 200°C, and burns at around 342°C. Therefore, when a cable fire occurs, the HDPE sheath softens and melts first. Once the combustion reaches a certain level, the HDPE sheathing then burns. After combustion, the flames can spread along the polyethylene sheathing. If the HDPE sheathing melts, deforms, or even burns due to the flames and high temperature, forming holes, the flames can further spread through these holes, increasing the cable's fire-damaged area. Furthermore, in steel strand cable-stayed systems, the cable body and anchorages contain significant amounts of grease, which acts as a combustion aid and accelerates the spread of fire. Therefore, preventing and isolating the spread of flames through the polyethylene sheathing and cable body is crucial for cable fire prevention.

[0006] Summary of the Invention

[0007] In view of the existing working conditions of the inclined cable, the present invention proposes a inclined cable fire arrester device and an installation method that can achieve preheating and bidirectional expansion. The device is installed on the inclined cable to prevent the spread of fire.

[0008] The technical solution adopted by the present invention is: a fire-blocking device for a cable-stayed cable that can achieve preheating bidirectional expansion, including a fire-blocking ring and a positioning clamp. The fire-blocking ring is fixedly arranged on the surface of the cable body by the positioning clamp, and the fire-blocking ring wraps the cable body. When heated, the fire-blocking ring expands inward to hug the cable body, and expands outward to isolate the cable bodies on both sides of the fire-blocking ring.

[0009] As one of the embodiments of the present application, the firestop ring is an integral structure, and the inclined cable body passes through the firestop ring; or the firestop ring is a half-type structure, and is arranged around the inclined cable body.

[0010] As one embodiment of the present application, a weather-resistant fireproof tape is wrapped around the cable body where the fireblock ring is installed, and the fireblock ring is then installed outside the fireproof tape. The fireblock ring does not directly contact the cable body, thus avoiding extrusion and damage to the high-density polyethylene layer on the cable body surface.

[0011] As one embodiment of the present application, the firestop ring includes a firestop ring shell, a firestop core material, and a clamp. The firestop core material is disposed within the firestop ring shell, and the clamp is clamped outside the firestop ring shell. The firestop ring shell provides daily protection for the firestop core material, reducing environmental interference with the firestop core material. The firestop ring shell is preferably made of high-density polyethylene.

[0012] As one of the embodiments of the present application, the fire-stop core material is annular in structure, and the fire-stop ring shell is a hollow annular structure. The fire-stop ring shell includes a fire-stop ring cylinder, a fire-stop ring upper cover plate, and a fire-stop ring lower cover plate. The fire-stop core material is arranged in the fire-stop ring cylinder, and the fire-stop ring upper cover plate and the fire-stop ring lower cover plate are respectively arranged at the upper and lower ports of the fire-stop ring cylinder to fix the fire-stop core material in the fire-stop ring cylinder.

[0013] As one of the embodiments of the present application, the shell of the firestop ring is made of high-density polyethylene with a thickness of not less than 3 mm, and the inner diameter of the shell of the firestop ring is 1 to 3 mm larger than the outer diameter of the inclined cable;

[0014] The settings of the inner diameter D1, outer diameter D2 and height H of the fire retardant core material are shown in the table below.

[0015] As one embodiment of the present application, the firestop ring housing has a positioning groove machined into its surface. This groove is used to accommodate the clamp, which secures the firestop ring housing in a half-structured configuration. The half-structure of the firestop ring housing facilitates installation of the firestop ring, adjustment of its mounting position on the cable body, and subsequent maintenance and updates.

[0016] As one embodiment of the present application, the positioning fixture is installed at the lower end of the firestop ring, with the bottom of the firestop ring supported on the positioning fixture. The positioning fixture is a half-structure and is enclosed outside the cable. The inner hole of the positioning fixture is filled with silicone rubber with a thickness of 5mm to 10mm, which is enclosed outside the cable. The contact between the silicone rubber and the cable body can protect the polyethylene sheath layer on the cable body during daily use, preventing damage to the cable body surface caused by installation of the positioning fixture.

[0017] As one embodiment of the present application, a connection hole is provided on the surface of the positioning fixture, and a connector is provided in the connection hole to connect the positioning fixture to the firestop ring, or a limiter is provided in the connection hole to form an external limit for the firestop ring. In this way, the positioning fixture can reliably support and position the firestop ring.

[0018] Fires in cable-stayed cables are mainly caused by burning vehicles traveling on the bridge deck or construction work at the tower end or beam end. Therefore, it is necessary to install fire-retardant devices that can achieve preheating bidirectional expansion (both inward and outward expansion) outside the embedded pipes at the beam end, the flame impact zone of the vehicle burning, and the tower end and other key locations. This will form an isolation at the fire location of the cable, blocking the flame from spreading along the cable body, and preventing the flame after the high-density polyethylene sheath burns from spreading along the cable body, thereby causing greater disasters.

[0019] The fire-blocking device designed in this application has a simple structure, is easy to install on the cable body, and is not interfered with by the cable's own structure, making it easy to promote and apply. This application uses a bidirectional intumescent fire-blocking core material as the core fire-blocking component. Utilizing its characteristic of thermal expansion, it hugs the cable body inward to prevent the spread of flames and expands outward to separate the cable body on both sides, thereby preventing the spread of fire.

[0020] The inventors of this application also hope to achieve the effect of extinguishing open flames by designing the structure of the fire arrester ring and the positioning fixture. The relevant implementation methods are as follows:

[0021] A fire-blocking device: comprises a fire-blocking ring and a fastening clamp; the fire-blocking ring comprises an inner sleeve and an outer sleeve; the outer sleeve is provided with an interlayer, the interlayer is filled with fire-extinguishing liquid, and the inner sleeve is slidably arranged in the outer sleeve; the outer edge of the top of the inner sleeve and the inner edge of the bottom of the outer sleeve are both provided with a blocking edge, 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, and the inner sleeve and the outer sleeve are fixed by the low-melting-point colloid; a liquid outlet connected to the interlayer is provided at the lower inner side of the outer sleeve, the outer end face of the liquid outlet is in contact with the outer wall of the inner sleeve, and a low-melting-point sealing point 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 of the inner sleeve, a fire-blocking core material is provided in the core material ring, and the fire-blocking core material is fixed in the core material ring by a fireproof tape.

[0022] The inner sleeve body is composed of two symmetrically arranged inner half sleeve bodies. The outer sides of the bottom ends of the two inner half sleeve bodies are each provided with a first fastening groove. The bottom ends between the two inner half sleeve bodies are fixed by the first fastening groove and the first clamp.

[0023] The outer casing is composed of two symmetrically arranged outer half casings. The circumferential sides of the two outer half casings are both provided with second fastening grooves, and the two outer half casings are fixed by the second fastening grooves and the second clamps.

[0024] An end sleeve is provided at the top of the outer sleeve, and a clamping edge is provided on the peripheral side of the end sleeve. The fastening clamp includes a group of symmetrically arranged semi-ring bodies, and the two semi-ring bodies are connected to each other by fastening bolts. A clamping groove that cooperates with the clamping edge is fixed on the lower part of the semi-ring body.

[0025] The fireproof ring and the fastening clamp are sleeved on the outside of the inclined cable body. The semi-ring body is provided with silicone rubber. The inner wall of the silicone rubber is in contact with the outer wall of the inclined cable. A clearance is formed between the inner side of the core material ring and the outer wall of the inclined cable.

[0026] The top end of the inner sleeve body is provided with a clearance opening, which is opposite to the liquid outlet.

[0027] The inner sleeve body is provided with guide ribs on its peripheral side surface, and the resistance edge is provided with slots, and the guide ribs slide along the guide slots.

[0028] The above-mentioned flame arresting device with flame extinguishing function has the following beneficial effects:

[0029] 1. The present invention designs a retractable inner sleeve and outer sleeve as a fire-blocking ring. The inner sleeve actively extends after the combustion spreads to the right position. At the same time, the design of the fire-blocking core material that can expand due to heat can completely cover the combustion spread point within the inner sleeve. The fire-blocking core material can be used to cut off the fire below the combustion spread point. The design of the fire extinguishing liquid in the outer sleeve can extinguish the fire in the space between the inner sleeve and the inclined cable body, thereby performing a fire-extinguishing cutoff above the combustion spread point, blocking the spread of flames along the cable body surface, and preventing the flames after the high-density polyethylene sheath burns from spreading along the inclined cable body, thereby causing more disasters.

[0030] 2. The present invention adopts the design of fire-retardant core material, which can expand during preheating and squeeze the softened or melted polyethylene sheath inward after heating, so as to block the combustion spread point below. At the same time, it can block the space between the inner sleeve and the inclined cable body, completely limiting the combustion spread point within the inner sleeve, not only cutting off the air used for combustion, but also providing space for the fire extinguishing liquid, thereby improving the fire-retardant effect of the fire-retardant ring.

[0031] 3. The inner sleeve and the outer sleeve of the present invention are connected and fixed by a low-melting-point colloid. The low-melting-point colloid has the function of identifying when the fire has spread to a certain position. When the fire spreads to a position close to the fire-blocking ring, the low-melting-point colloid actively melts to enable the inner sleeve to actively extend to cover the spreading point.

[0032] 4. The present invention seals the liquid outlet through a low-melting-point sealing point. The low-melting-point sealing point is equivalent to a switch function when the fire spreads to a certain position. When the fire spreads to a position close to the fire-blocking ring, the low-melting-point sealing point actively melts to open the liquid outlet.

[0033] 5. The present invention designs the inner casing, outer casing and fastening clamp as two symmetrically arranged structural parts, which can be quickly installed on the inclined cable body, which is convenient for the installation, removal, maintenance and replacement of the fire arrester and the operation of the staff.

[0034] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a schematic diagram of the installation of the stay cable fire arrester in Example 1 of the present application;

[0036] FIG2 is a central cross-sectional view of the fire arrester in Example 1 of the present application;

[0037] FIG3 is a central cross-sectional view of the fire arrester ring cylinder in Example 1 of the present application;

[0038] FIG4 is a schematic structural diagram of the firestop ring upper cover plate or the firestop ring lower cover plate in Example 1 of the present application;

[0039] FIG5 is a schematic structural diagram of the fire arrester ring housing in Example 1 of the present application;

[0040] FIG6 is a central cross-sectional view of the assembled fire arrester device in Example 1 of the present application;

[0041] FIG7 is a schematic diagram of the installation of the fire arrester in Example 1 of the present application;

[0042] FIG8 is a schematic structural diagram of the positioning fixture in Example 1 of the present application;

[0043] In Figure 1-8, 1 is a fire-blocking ring, 2 is a positioning fixture, 201 is a connecting hole, 3 is a rain cover at the end of the cable-stayed beam, 4 is a pre-buried pipe at the end of the cable-stayed beam, 5 is a white high-density polyethylene sheath, 6 is a black high-density polyethylene sheath, 7 is a steel wire bundle of the cable, 8 is a weather-resistant fire-blocking tape, 9 is a fire-blocking ring shell, 10 is a fire-blocking core material, 11 is a clamp, 12 is a silicone rubber, and 13 is a screw.

[0044] FIG9 is a schematic structural diagram of the fire arrester in Example 2 of the present application;

[0045] FIG10 is a cross-sectional view of the structure of the fire arrester in Example 2 of the present application in a normal state;

[0046] FIG11 is a cross-sectional view of the structure of the fire arresting device in Example 2 of the present application when the fire is arrested;

[0047] In Figures 9-11, 1-fastening fixture, 2-inner sleeve, 3-outer sleeve, 4-stayed cable body, 101-semi-ring, 102-clip groove, 103-silicone rubber pad, 201-resistance edge, 202-cavity, 203-low melting point colloid, 204-core material ring, 205-fire retardant core material, 206-fireproof tape, 207-inner half sleeve, 208-first fastening groove, 209-first clamp, 210-yield port, 301-interlayer, 302-liquid outlet, 303-low melting point sealing point, 304-end sleeve, 305-clip edge, 306-outer half sleeve, 307-second fastening groove, 308-second clamp. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below with reference to the accompanying drawings. The embodiments described are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention. The textual descriptions in this embodiment correspond to the accompanying drawings, and the descriptions of the directions are also based on the descriptions of the accompanying drawings, and should not be construed as limiting the scope of protection of the present invention.

[0049] Example 1

[0050] As shown in FIG1-9 , the stay cable fire arrester device includes a fire arrester ring 1 and a positioning fixture 2 . The fire arrester ring 1 includes a fire arrester ring shell 9 , a fire arrester core material 10 and a clamp 11 . The fire arrester prevents fire from spreading along the high-density polyethylene sheathing by the following principle: When a fire occurs locally within the cable, the device's polyethylene fire ring shell first softens (around 120°C), melts (around 180°C), and then burns (around 345°C). The fire arrester's core material, mounted outside the cable's polyethylene sheathing, is exposed to the flames and high temperatures, undergoing a chemical reaction and rapidly expanding into a dense, strong carbonized layer. This expands outward, forming a large fire ring, which simultaneously squeezes the softened or melted polyethylene sheathing inward. This quickly seals any holes in the cable's polyethylene sheathing caused by the heat, such as softening or burning. This prevents the flame from propagating along the cable's polyethylene sheathing toward the tower or beam ends, halting the spread of fire and eliminating the potential for cable load-bearing failure, particularly premature failure at the anchorage, caused by the spread of localized cable combustion. Fire rings can be either integral or half-length. When the fire-stop device adopts an integral fire-stop device, it is pre-inserted into the cable body before the inclined cable is anchored.

[0051] The technical requirements for the stay cable fire arrester and its accessory components are as follows:

[0052] 1. The fire-blocking ring shell of the fire-blocking device is made of high-density polyethylene and has a thickness of no less than 3mm. The inner diameter of the shell is 1 to 3mm larger than the outer diameter of the polyethylene sheath of the cable body. When the polyethylene sheath of the cable body burns, the fire-blocking ring shell melts first, ensuring that the fire-blocking core material can rapidly expand inward and outward by 20 to 40 times, forming a huge fire-blocking ring, effectively preventing the spread of fire along the cable body. The fire-blocking ring shell is made of high-density polyethylene with strong aging resistance. The performance parameters of this polyethylene material are as follows:

[0053] Technical requirements for high-density polyethylene shell materials

[0054] The processing method of high-density polyethylene shell (fireproof ring shell) is as follows:

[0055] 1) According to the design size, hot extrude the high-density polyethylene casing and cut it according to the required height to form the high-density polyethylene shell cylinder of the inclined cable fire arrester. Two positioning grooves with a width of 10-20 mm and a depth of 1 mm-2 mm are processed on the cylinder, and the cylinder is cut from the center line.

[0056] 2) According to the design requirements, the upper and lower cover plates of the high-density polyethylene shell of the fire-blocking device are processed and cut along the center line to form two semicircular rings.

[0057] 3) Use a polyethylene special hot melt welding gun or a polyethylene special ultrasonic welding gun to weld the upper and lower cover plates and the cylinder of the high-density polyethylene shell into a whole to form a high-density polyethylene shell of the fire-blocking device, that is, the fire-blocking ring shell.

[0058] 2. The fire retardant core material of the fire retardant device can be a chemical expansion type flame retardant or a physical expansion type flame retardant.

[0059] Chemical intumescent flame retardants consist of three components: an acid source (dehydrating agent), a carbon source (carbonizing agent), and a gas source (foaming agent). The acid source primarily includes phosphorus oxychloride phosphate (POC) and ammonium polyphosphate (AMPP). Carbon sources, primarily polyols or carbohydrates with a high carbon content, form the basis for the carbonized layer of the foam. Examples include phenolic resin, polyamide, butanetriol, maltose, and starch. The gas source, also called a foaming source, commonly includes melamine, dicyandiamide, ammonium polyphosphate, and urea. These gas source materials release large amounts of non-flammable gases upon thermal decomposition, which act as a foaming agent and expand the carbonized layer. In summary, the flame retardant mechanism of chemical intumescent flame retardants is as follows: When heated, the acid source decomposes to produce a dehydrating agent, which reacts with the AMP to form an ester. The ester then dehydrates and crosslinks to form char. Simultaneously, the foaming agent releases a large amount of gas, which helps expand the char layer. The thick carbon layer increases the temperature gradient between the polymer surface and the carbon layer surface, making the polymer surface temperature much lower than the flame temperature, reducing the possibility of further degradation of the polymer to release combustible gases, and at the same time isolating the entry of external oxygen, thus having a flame retardant effect on the polymer for a considerable period of time.

[0060] The core material of the fire-retardant device can also be made of physical expandable graphite material. At high temperatures, the expandable graphite expands rapidly, suffocating the flame. At the same time, the generated graphite expanded material covers the surface of the substrate, isolating the contact between heat radiation and oxygen; the acid radicals inside the interlayer are released during expansion, which also promotes the carbonization of the substrate, thereby achieving good results through a variety of flame retardant methods.

[0061] The volume of the fire-retardant core material of the fire-retardant device can expand by 20 to 40 times of its original volume when heated.

[0062] The fire-retardant core material of the fire-retardant device adopts a semi-ring shape, and the relevant dimensions of the ring are determined according to the following table.

[0063] The schematic diagram of the assembled fire arrester is shown in Figure 6:

[0064] 3. In order to prevent the fire-blocking device shell and fire-blocking core material from damaging the high-density polyethylene sheath during the operation of the inclined cable,

[0065] To prevent collision and friction, wrap a 3-6mm thick weather-resistant fireproof tape (such as polyvinyl fluoride tape) around the location where the fire arrester is installed.

[0066] 4. To prevent the fire arrester ring from falling off, a flange with a hole is installed on the outer shell of the fire arrester ring. By connecting with the positioning fixture below, the fire arrester ring is positioned to prevent it from slipping or falling off during the operation of the cable-stayed bridge. The Huff-type fire arrester positioning fixture can be installed before the cable-stayed cables are anchored, or after the cables are anchored or installed.

[0067] 5. A positioning fixture 2 is installed at the lower end of the fire arrester. The positioning fixture adopts a half-type structure, and the two parts are connected by a screw 13. To protect the polyethylene sheath of the inclined cable from damage by the fixture, a silicone rubber 12 with a thickness of 5mm to 10mm and a Shore hardness of 50 to 60 is installed in the inner hole of the fixture.

[0068] Example 2

[0069] As shown in Figures 9-11, this embodiment relates to a fire-blocking device with the function of extinguishing open flames: comprising a fire-blocking ring and a fastening fixture 1; the fire-blocking ring comprises an inner sleeve 2 and an outer sleeve 3; an interlayer 301 is provided in the outer sleeve 3, and the interlayer 301 is filled with a fire-extinguishing liquid (such as water or fine sand), and the inner sleeve 2 is slidably arranged in the outer sleeve 3; a barrier edge 201 is provided at 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, and a cavity 202 is formed between the inner sleeve 2 and the outer sleeve 3, and a low-melting-point colloid 20 is provided at the bottom of the cavity 202. 3. The inner casing 2 and the outer casing 3 are fixed by a low-melting-point colloid 203; a liquid outlet 302 communicating with the interlayer 301 is provided at the inner lower part of the outer casing 3, the outer end face of the liquid outlet 302 is in contact with the outer wall of the inner casing 2, and a low-melting-point sealing point 303 is fixed at the inner end of the liquid outlet 302; a core material ring 204 with a C-shaped cross section is fixed at the inner lower part of the inner casing 2, a fire-retardant core material 205 is provided in the core material ring 204, and the fire-retardant core material 205 is fixed in the core material ring 204 by a fire-retardant tape 206 (such as polyvinyl fluoride tape).

[0070] The inner casing 2 is composed of two symmetrically arranged inner half casings 207. The outer sides of the bottom ends of the two inner half casings 207 are each provided with a first fastening groove 208. The bottom ends of the two inner half casings 207 are fixed by the first fastening groove 208 and the first clamp (209). The top of the inner casing 2 is provided with a clearance opening 210, which is located opposite to the liquid outlet 302. The inner casing 2 is provided with guide ribs on the side surface, and a notch is provided on the resistance edge 201. The guide ribs slide along the guide grooves.

[0071] The outer casing 3 is composed of two symmetrically arranged outer casing halves 306. Both outer casing halves 306 are provided with second fastening grooves 307 on their lateral sides. The two outer casing halves 306 are secured together by the second fastening grooves 307 and the second clamp 308. An end sleeve 304 is provided at the top of the outer casing 3, and a clamping edge 305 is provided on its lateral sides. The fastening fixture 1 comprises a pair of symmetrically arranged half-rings 101, which are connected to each other by fastening bolts. A clamping groove 102 is fixed to the lower inner portion of each half-ring 101, which mates with the clamping edge 305.

[0072] The fireproof ring and the fastening clamp 1 are sleeved on the outside of the inclined cable body 4, and a silicone rubber pad 103 is provided in the semi-ring body 101. The inner wall of the silicone rubber pad 103 fits the outer wall of the inclined cable body 4, and a clearance is formed between the inner side of the core material ring 204 and the outer wall of the inclined cable body 4.

[0073] The working principle of the fire arrester in this embodiment is:

[0074] When a fire breaks out in the sheath layer of the cable body 4 and spreads to a location close to the device, the combustion temperature will pre-melt the low-melting-point colloid 203 and the low-melting-point seal 303. The low-melting-point seal 303 is a sealing point formed by the low-melting-point colloid. In the high temperature environment caused by the flame, the low-melting-point colloid will melt.

[0075] The melting of the low-melting-point colloid 203 will release the fixation between the inner sleeve 2 and the outer sleeve 3, and the inner sleeve 2 will drop due to gravity. At this time, the spreading burning point is inside the inner sleeve 2 and above the fire-retardant core material 205, thereby wrapping the burning point inside the inner sleeve 2, and the fire-retardant tape 206 melts with high temperature and the fire-retardant core material 205 expands due to heat, and the inside of the expanded fire-retardant core material 205 wraps the outside of the burned rope body below the burning point.

[0076] The melting of the low-melting-point sealing point 303 is equivalent to opening the liquid outlet 302. During the process of the inner casing 2 sliding downward along the outer casing 3, the end of the liquid outlet 302 adheres to the outer wall of the inner casing 2 and continues to seal it to a certain extent. After the inner casing 2 falls completely, the liquid outlet 302 is exposed to the outside, and the fire-extinguishing liquid in the interlayer 301 is discharged to the gap between the inner casing 2 and the inclined cable body 4 by gravity, and the bottom of the gap is blocked by the expanded fire-retardant core material 205. Therefore, the burning point retained in the inner casing 2 can be extinguished and flame-retarded, and the spread of the burning point can be directly cut off.

Claims

1. A stay cable fire-blocking device capable of achieving bidirectional expansion when heated, characterized in that: It comprises a fire-blocking ring and a positioning fixture. The fire-blocking ring is fixedly arranged on the surface of the inclined cable body by the positioning fixture. The fire-blocking ring wraps the inclined cable body. When heated, the fire-blocking ring expands inwards to hold the inclined cable body tightly, and expands outwards to separate the inclined cable bodies on both sides of the fire-blocking ring.

2. The fire-blocking device for the inclined cable capable of realizing bidirectional expansion when heated according to claim 1 is characterized in that: The fire-blocking ring is an integral structure, and the cable body of the inclined cable passes through the fire-blocking ring; or the fire-blocking ring is a half-type structure, and is arranged around the cable body of the inclined cable.

3. The fire-blocking device for the inclined cable capable of realizing bidirectional expansion when heated according to claim 1 is characterized in that: A weather-resistant fireproof tape is wound around the cable body of the inclined cable where the fire-blocking ring is arranged, and the fire-blocking ring is arranged on the outside of the fire-blocking tape.

4. The fire-blocking device for inclined cables capable of bidirectional expansion when heated according to claim 1 is characterized in that: The firestop ring comprises a firestop ring shell, a firestop core material and a clamp, wherein the firestop core material is arranged inside the firestop ring shell, and the clamp is clamped outside the firestop ring shell.

5. The fire-blocking device for the inclined cable capable of realizing bidirectional expansion when heated according to claim 4 is characterized in that: The fire-blocking core material is an annular structure, and the fire-blocking ring outer shell is a hollow annular structure. The fire-blocking ring outer shell includes a fire-blocking ring cylinder, a fire-blocking ring upper cover plate, and a fire-blocking ring lower cover plate. The fire-blocking core material is arranged in the fire-blocking ring cylinder, and the fire-blocking ring upper cover plate and the fire-blocking ring lower cover plate are respectively arranged at the upper and lower ports of the fire-blocking ring cylinder, and a sealing ring is arranged at the joint to fix the fire-blocking core material in the fire-blocking ring cylinder.

6. The stay cable fire-blocking device capable of achieving bidirectional expansion when heated according to claim 4, characterized in that: The shell of the fire-blocking ring is made of high-density polyethylene with a thickness of not less than 3 mm. The inner diameter of the shell of the fire-blocking ring is 1 to 3 mm larger than the outer diameter of the cable. The settings of the inner diameter D1, outer diameter D2 and height H of the fire-retardant core material are shown in the table below.

7. The stay cable fire-blocking device capable of achieving bidirectional expansion when heated according to claim 1, characterized in that: A positioning groove is processed on the surface of the fire-blocking ring shell, and the positioning groove is used to set the clamp, and the clamp fixes the fire-blocking ring shell of the half-structure as a whole.

8. The stay cable fire-blocking device capable of achieving bidirectional expansion when heated according to claim 1, characterized in that: The positioning fixture is arranged at the lower end of the fireblocking ring, and the bottom of the fireblocking ring is supported on the positioning fixture. The positioning fixture is a half structure, which is embraced outside the inclined cable body. The inner hole of the positioning fixture is provided with silicone rubber with a thickness of 5mm to 10mm, and the silicone rubber is embraced outside the inclined cable body.

9. The stay cable fire-blocking device capable of achieving bidirectional expansion when heated according to claim 8, characterized in that: A connecting hole is arranged on the surface of the positioning fixture, and the positioning fixture is connected to the fire-blocking ring by arranging a connecting piece in the connecting hole, or an outer limit is formed on the fire-blocking ring by arranging a limiting piece in the connecting hole.

10. The stay cable fire arrester capable of realizing preheating bidirectional expansion according to claim 1, characterized in that: The positioning fixture is a fastening fixture; the fire-blocking ring includes an inner sleeve and an outer sleeve; an interlayer is provided in the outer sleeve, the interlayer is filled with fire-extinguishing liquid, and the inner sleeve is slidably arranged in the outer sleeve; a blocking edge is provided at 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, and the inner sleeve and the outer sleeve are fixed by the low-melting-point colloid; a liquid outlet connected to the interlayer is provided at the lower inner side of the outer sleeve, the outer end face of the liquid outlet is in contact with the outer wall of the inner sleeve, and a low-melting-point sealing point 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 inner sleeve, a fire-blocking core material is provided in the core material ring, and the fire-blocking core material is fixed in the core material ring by a fireproof tape.

Images