Fireproof early warning computer cable with built-in multi-point temperature measuring optical fiber

Abstract

The present application relates to the technical field of computer cable, in particular to a fireproof early warning computer cable with built-in multi-point temperature measurement optical fiber, characterized in that it comprises: a conductor, the conductor is coated with an insulating layer outside; an optical fiber; and a plurality of thermal deformation units distributed along the length direction of the cable, the present application uses the thermal expansion of phase change material as the only driving source, does not depend on any electronic elements or external power supply, completely solves the problem of temperature measurement system failure after power failure, and permanently records the overheating event. When the cable overheats, the C-shaped elastic ring plastically deforms and locks, the optical fiber is permanently squeezed to produce bending loss, the loss state cannot be restored after cooling, even if the power is off for many years, it can still be read remotely by OTDR, the above two effects are related to each other: because the passive phase change drive and the plastic locking mechanism are adopted, the permanent recording function without power supply is realized, thereby solving the technical problem which has existed for a long time in the prior art but has not been overcome.

Description

Technical Field

[0001] This invention relates to the field of computer cable technology, and specifically to a fire-prevention and early warning computer cable with built-in multi-point temperature measurement optical fiber. Background Technology

[0002] Computer cables are widely used in data centers, power plants, subways, and other locations with high requirements for signal transmission and fire safety. During long-term operation, localized overheating caused by overload, poor contact, or insulation aging is a major cause of fires.

[0003] In existing technologies, a few cables integrate multi-point temperature sensing optical fibers, enabling real-time monitoring of temperature distribution. However, this type of solution has a fundamental flaw: the optical fiber only serves as a real-time sensing element, and temperature data is stored in an external host. If a fire causes a power outage or damage to the host, historical overheating data is immediately lost, making it impossible to trace the cause of the fire. Furthermore, electronic temperature measurement solutions rely on continuous power supply and become completely ineffective after a power outage.

[0004] Therefore, how to enable the cable itself to permanently record historical overheating events and make them available for remote reading afterward without the need for external power supply is a long-standing but unresolved technical problem in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a fire prevention and early warning computer cable with built-in multi-point temperature measurement optical fiber, which addresses the shortcomings of the prior art in that cable overheating events cannot be permanently recorded and data is lost after power failure.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a fire prevention and early warning computer cable with built-in multi-point temperature measurement optical fiber, characterized in that it includes: a conductor, the conductor being covered with an insulating layer; an optical fiber; and a plurality of thermally deformable units distributed along the length of the cable. Each thermally induced deformation unit includes: a housing, embedded in the inner sheath of the cable; a phase change medium cavity, disposed within the housing, filled with a phase change material that changes from solid to liquid and expands in volume above a preset temperature; a piston, disposed within the housing and communicating with the phase change medium cavity; and a C-shaped elastic ring, with a central hole for an optical fiber to pass through. When the phase change material melts and expands, it drives the piston to move. The piston then drives related components to squeeze the C-shaped elastic ring, reducing its inner diameter and squeezing the optical fiber to generate bending loss.

[0007] As a preferred embodiment of the present invention, a thermally conductive transition layer is further provided between the conductor and the insulating layer; the thermally induced deformation unit also includes a push rod and a wedge, one end of the push rod is connected to a piston, and the other end is connected to the wedge, the inclined surface of the wedge is in contact with the outer circular surface of the C-shaped elastic ring.

[0008] As a preferred embodiment of the present invention, the thermo-deformation unit further includes a piston rod, a ratchet rack, and a pawl. The piston rod is connected to the piston, the ratchet rack is disposed on the piston rod, and the pawl is fixed to the housing. The pawl engages with the ratchet rack to prevent the piston from retracting. The thermo-deformation unit also includes a return spring, which is sleeved on the piston rod. One end of the return spring abuts against the piston, and the other end abuts against the housing.

[0009] As a preferred embodiment of the present invention, an O-ring is provided between the piston and the housing; the thermally induced deformation unit also includes a capillary damping orifice, which is disposed in the channel between the phase change medium cavity and the piston, and is used to control the flow rate of the phase change material after melting.

[0010] As a preferred embodiment of the present invention, two adjacent arc-shaped grooves are formed on the outer surface of the thermally conductive transition layer. A phase change medium tube and a stainless steel loose tube are respectively installed in the two arc-shaped grooves. The phase change medium tube is connected to the phase change medium cavity, and an optical fiber is concentrically arranged in the stainless steel loose tube.

[0011] As a preferred embodiment of the present invention, the outer surface of the stainless steel loose sleeve is provided with a plurality of axially extending microgrooves along the circumferential direction, and each microgroove is embedded with a low melting point alloy wire, and the low melting point alloy wires in different microgrooves have different melting points.

[0012] As a preferred embodiment of the present invention, the phase change medium tube and the stainless steel loose tube are fixed together by binding with polyester straps.

[0013] As a preferred embodiment of the present invention, the insulation layer, the thermally conductive transition layer, the phase change medium tube, and the stainless steel loose tube are sequentially covered with an inner sheath, an armor, and an outer sheath.

[0014] As a preferred embodiment of the present invention, the C-shaped elastic ring is made of beryllium copper and the phase change material is a composite of paraffin and expanded graphite; the thermally induced deformation unit also includes a fixing bracket, which is installed inside the housing to support the C-shaped elastic ring.

[0015] As a preferred embodiment of the present invention, the number of thermo-deformation units is one every 1.5 to 2.5 meters.

[0016] Compared with the prior art, the present invention has the following beneficial effects: First, it requires no external power supply and is inherently safe. This invention uses the thermal expansion of phase change materials as the sole driving source, without relying on any electronic components or external power supply, thus completely solving the problem of temperature measurement system failure after power failure.

[0017] Second, overheating events are permanently recorded. When the cable overheats, the C-shaped elastic ring undergoes plastic deformation and locks, and the optical fiber is permanently compressed, resulting in bending loss. This loss state is irreversible after cooling and can still be read remotely via OTDR even after years of power outage.

[0018] The two effects mentioned above are related: it is precisely because of the use of passive phase change drive and plastic locking mechanism that the permanent recording function without power supply is realized, thereby solving the technical problem that has long existed in the prior art but has not been overcome. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of the cable of the present invention; Figure 2 For the present invention Figure 1 Enlarged structural diagram at point A in the middle; Figure 3 This is a schematic diagram of the longitudinal section structure of the thermo-deformation unit of the present invention; Figure 4 for Figure 3 Schematic diagram of the partial structure of the C-shaped ring and optical fiber; Figure 5 This is a partial assembly diagram of the piston-pawl-spring system.

[0021] The labels in the diagram represent: 1. Conductor; 2. Insulation layer; 3. Thermally conductive transition layer; 4. Phase change medium tube; 5. Stainless steel loose tube; 6. Optical fiber; 7. Microgroove; 8. Low melting point alloy wire; 9. Polyester binding tape; 10. Inner sheath; 11. Armor; 12. Outer sheath; 13. Housing; 14. Phase change medium cavity; 15. Piston; 16. O-ring seal; 17. Piston rod; 18. Return spring; 19. Ratchet; 20. Pawl; 21. Push rod; 22. Wedge; 23. C-shaped elastic ring. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] The present invention will be further described below with reference to embodiments.

[0024] Example 1:

[0025] like Figures 1 to 5 As shown in the figure, this embodiment provides a fire prevention and early warning computer cable with built-in multi-point temperature measurement optical fiber.

[0026] like Figure 1 As shown, the center of the cable is conductor 1, which is made of multi-strand tinned copper stranded wire. Conductor 1 is covered with an insulation layer 2 by an extrusion process; the insulation layer 2 is made of cross-linked polyethylene. The outer surface of the insulation layer 2 is coated with a thermally conductive transition layer 3, which is made of graphene-doped silicone grease, used to reduce the contact thermal resistance between the insulation layer 2 and external conduits.

[0027] The multi-point temperature measurement fiber described in this invention refers to a fiber optic sensing element capable of measuring the temperature at multiple continuous locations along the fiber's length, including but not limited to distributed temperature measurement fibers based on the principle of optical time-domain reflectometry.

[0028] Two adjacent arc-shaped grooves are formed on the outer surface of the insulation layer 2. A phase change medium tube 4 and a stainless steel loose tube 5 are respectively installed in the two arc-shaped grooves. Then, a thermally conductive transition layer 3 is coated on the outer surface of the insulation layer 2 and the two tubes.

[0029] The phase change medium tube 4 is made of medical-grade silicone tubing, which is continuously arranged along the entire length of the cable, terminates at the thermal deformation unit and is sealed to the inlet of the phase change medium cavity 14 inside the housing 13.

[0030] The stainless steel loose tube 5 is made of SUS304 stainless steel, with a corrugated wall to increase bending flexibility. An optical fiber 6, a standard single-mode fiber, is concentrically installed inside the stainless steel loose tube 5. Thixotropic grease is filled between the stainless steel loose tube 5 and the optical fiber 6 to buffer mechanical stress and provide waterproofing.

[0031] like Figure 2 As shown, the outer surface of the stainless steel loose sleeve 5 has multiple axially extending microgrooves 7 along the circumference. The microgrooves 7 are V-shaped grooves and are evenly distributed along the outer surface of the stainless steel loose sleeve 5. Each microgroove 7 is embedded with a low melting point alloy wire 8. The melting points of each alloy wire are different, namely 55℃, 70℃, 85℃ and 105℃.

[0032] The phase change medium tube 4 and the stainless steel loose tube 5 are placed side by side and tightly attached, and the two are tied together by polyester strapping 9.

[0033] All the aforementioned components are sequentially covered by an inner sheath 10, an armor 11, and an outer sheath 12. The inner sheath 10 is made of ceramicized silicone rubber and is applied to the outside of the cable core via extrusion. The armor 11 is a spiral-wound structure made of galvanized steel strip. The outer sheath 12 is made of low-smoke halogen-free flame-retardant polyolefin.

[0034] like Figure 3As shown, a thermo-deformation unit is arranged at regular intervals along the length of the cable. Each thermo-deformation unit includes a housing 13, which is embedded in the solid material of the inner sheath 10. The housing 13 is divided into an upper half and a lower half, which are embedded in the upper and lower walls of the inner sheath 10, respectively.

[0035] A phase change medium cavity 14 is provided inside the shell 13. The phase change medium cavity 14 is a cylindrical cavity located on the left side of the shell 13. The phase change medium cavity 14 is filled with a phase change material, which is a composite of paraffin wax and expanded graphite, and its melting point is set to about 60°C.

[0036] The right side of the phase change medium cavity 14 is connected to the piston cylinder through a capillary damping orifice. The capillary damping orifice has a small diameter and is used to control the speed at which the phase change material flows into the piston cylinder after melting, preventing false triggering caused by transient temperature spikes.

[0037] like Figure 4-5 As shown, the piston cylinder is located to the right of the capillary damping orifice. A piston 15, made of brass and cylindrical in shape, is housed within the piston cylinder. The gap between the piston 15 and the inner wall of the piston cylinder is sealed by an O-ring 16. The O-ring 16, made of fluororubber, is installed in a sealing groove on the outer circumference of the left side of the piston 15.

[0038] A piston rod 17, made of stainless steel, is fixedly connected to the right side of piston 15. A return spring 18, a stainless steel helical compression spring, is fitted onto piston rod 17 and is in a compressed state. The left end of the return spring 18 abuts against the right side of piston 15, and the right end abuts against the right step of piston cylinder.

[0039] The upper surface of the piston rod 17 is machined with a ratchet rack 19, the tips of which face to the right. A pawl 20, made of stainless steel and with a cantilever beam structure, is mounted on the top wall of the housing 13. The tip of the pawl 20 presses against the ratchet rack 19, engaging with the tooth grooves of the rack 19. The pawl 20 and the ratchet rack 19 form a one-way locking mechanism, allowing the piston 15 to move to the right but preventing it from retracting to the left.

[0040] A push rod 21, made of stainless steel, is fixedly connected to the right end of the piston rod 17. A wedge 22, also made of stainless steel, is fixed to the right end of the push rod 21. The wedge 22 is wedge-shaped with its inclined surface facing downwards.

[0041] A C-shaped elastic ring 23 is disposed directly below the wedge 22. The C-shaped elastic ring 23 is made of beryllium copper, which has good elasticity and plastic deformation capacity. The C-shaped elastic ring 23 has an open annular structure. The C-shaped elastic ring 23 is installed at the bottom of the housing 13 by a fixed bracket.

[0042] Optical fiber 6 emerges from the loose stainless steel tube 5, enters the housing 13, passes horizontally through the central hole of the C-shaped elastic ring 23, and then returns to the loose stainless steel tube 5 to continue extending. At room temperature, a gap remains between optical fiber 6 and the wall of the central hole of the C-shaped elastic ring 23, and optical fiber 6 is not subjected to force.

[0043] The working process of this embodiment is as follows: When the cable is working normally, the temperature is below the melting point of the phase change material, the phase change material remains solid, the piston 15 is in the initial position, the wedge 22 and the C-shaped elastic ring 23 are in a relaxed state, the optical fiber 6 is not squeezed, and the optical transmission loss is normal.

[0044] When the cable's local temperature rises above the melting point of the phase change material due to overload, poor contact, or insulation aging, the phase change material in the phase change medium cavity 14 begins to melt and expand in volume. The molten phase change material slowly flows into the right side of the piston cylinder through the capillary damping orifice, pushing the piston 15 to the right under pressure. The piston 15 then drives the piston rod 17, push rod 21, and wedge 22 to move to the right together.

[0045] When the wedge 22 moves to the right, its inclined surface slides relative to the outer circular surface of the C-shaped elastic ring 23. Under the action of the inclined surface, the C-shaped elastic ring 23 is subjected to downward compressive force, and its opening gradually closes, and its inner diameter gradually shrinks. When the piston 15 moves to a certain stroke, the inner diameter of the C-shaped elastic ring 23 shrinks to a size smaller than the outer diameter of the optical fiber 6, and the optical fiber 6 is squeezed and bent, resulting in bending loss.

[0046] As piston 15 moves to the right, ratchet rack 19 moves to the right along with piston rod 17, and pawl 20 slides across the tooth surface and falls into the next tooth groove. When piston 15 is in position, pawl 20 engages ratchet rack 19, preventing piston 15 from retracting to the left. Simultaneously, C-shaped elastic ring 23 undergoes plastic deformation. Even if the temperature drops and the phase change material solidifies, C-shaped elastic ring 23 will not return to its original shape, and optical fiber 6 remains compressed.

[0047] Afterwards, maintenance personnel connected an OTDR to one end of fiber 6, emitted optical pulses, and received backscattered signals. At the location of the overheating event, a distinct loss peak appeared on the OTDR curve due to the permanent bending loss of fiber 6. By measuring the distance to the loss peak, the location of the overheating could be precisely pinpointed; by measuring the depth of the loss peak, the severity of the overheating could be determined. Because the plastic deformation of the C-shaped elastic ring 23 and the ratchet locking mechanism are both irreversible mechanisms, this loss peak still exists even after the cable has been de-energized for many years, allowing for post-event traceability.

[0048] Furthermore, when the temperature reaches different thresholds, the corresponding melting point alloy wires on the surface of the stainless steel loose tube 5 will melt and break. After the alloy wires melt and break, they seep into the braided gaps of the stainless steel loose tube 5, causing the optical fiber 6 to generate additional characteristic bending loss at that location, thereby providing multi-level temperature warning information.

[0049] Example 2

[0050] This embodiment is basically the same as Embodiment 1, except that the phase change medium tube 4 and the stainless steel loose-sleeve tube 5 are not semi-embedded, but are directly placed in the gap between the outer surface of the thermally conductive transition layer 3 and the inner sheath 10, and are fixed by binding with polyester straps 9. This method simplifies the production process and eliminates the need to groove the surface of the thermally conductive transition layer 3.

[0051] This embodiment is applicable to situations where there are no strict restrictions on the outer diameter of the cable.

[0052] Industrial applicability

[0053] The fire-prevention computer cable with built-in temperature-sensing optical fiber provided by this invention can be manufactured on a conventional cable production line, and all materials are commercially available and mature. This cable can directly replace existing computer cables without the need for modification of supporting equipment, and has good industrial practicality and market promotion value.

[0054] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fire-prevention early warning computer cable with built-in multi-point temperature measurement optical fiber, characterized in that, include: Conductor (1), the conductor (1) is covered with an insulating layer (2); optical fiber （6）； And several thermally induced deformation units distributed along the length of the cable; Each of the aforementioned thermo-deformation units includes: a housing (13) embedded in the inner sheath (10) of the cable; A phase change medium cavity (14) is disposed inside the housing (13) and filled with a phase change material that changes from solid to liquid and expands in volume at a preset temperature; a piston (15) is disposed inside the housing (13) and communicates with the phase change medium cavity (14); and a C-shaped elastic ring (23) with a central hole for the optical fiber (6) to pass through; when the phase change material melts and expands, it drives the piston (15) to move, and the piston (15) drives related components to squeeze the C-shaped elastic ring (23), reducing its inner diameter and squeezing the optical fiber (6) to generate bending loss.

2. The fire-prevention early warning computer cable according to claim 1, characterized in that, A thermally conductive transition layer (3) is also provided between the conductor (1) and the insulating layer (2); the thermally deformable unit also includes a push rod (21) and a wedge (22), one end of the push rod (21) is connected to the piston (15), and the other end is connected to the wedge (22), and the inclined surface of the wedge (22) is in contact with the outer circular surface of the C-shaped elastic ring (23).

3. The fire-prevention early warning computer cable according to claim 1, characterized in that, The thermo-deformation unit further includes a piston rod (17), a ratchet rack (19), and a pawl (20). The piston rod (17) is connected to the piston (15). The ratchet rack (19) is disposed on the piston rod (17). The pawl (20) is fixed on the housing (13). The pawl (20) engages with the ratchet rack (19) to prevent the piston (15) from retracting. The thermo-deformation unit further includes a return spring (18). The return spring (18) is sleeved on the piston rod (17). One end of the return spring (18) abuts against the piston (15), and the other end abuts against the housing (13).

4. The fire-prevention early warning computer cable according to claim 1, characterized in that, An O-ring (16) is provided between the piston (15) and the housing (13); the thermo-deformation unit also includes a capillary damping hole, which is provided in the channel between the phase change medium cavity (14) and the piston (15) to control the flow rate of the phase change material after melting.

5. The fire-prevention early warning computer cable according to claim 2, characterized in that, Two adjacent arc-shaped grooves are formed on the outer surface of the thermally conductive transition layer (3). A phase change medium tube (4) and a stainless steel loose tube (5) are respectively installed in the two arc-shaped grooves. The phase change medium tube (4) is connected to the phase change medium cavity (14). The optical fiber (6) is concentrically arranged in the stainless steel loose tube (5).

6. The fire-prevention early warning computer cable according to claim 5, characterized in that, The outer surface of the stainless steel loose sleeve (5) is provided with a plurality of axially extending microgrooves (7) along the circumferential direction. Each microgroove (7) is embedded with a low melting point alloy wire (8). The low melting point alloy wire (8) in different microgrooves (7) has a different melting point. The microgrooves (7) are V-shaped grooves, and there are four of them. They are evenly distributed along the outer surface of the stainless steel loose sleeve (5). The melting points of the low melting point alloy wire (8) in the four microgrooves (7) are 55°C, 70°C, 85°C and 105°C, respectively.

7. The fire-prevention early warning computer cable according to claim 5, characterized in that, The phase change medium tube (4) and the stainless steel loose tube (5) are tied together and fixed by polyester straps (9).

8. The fire-prevention early warning computer cable according to claim 5, characterized in that, The insulation layer (2), the thermally conductive transition layer (3), the phase change medium tube (4) and the stainless steel loose tube (5) are sequentially covered by the inner sheath (10), the armor (11) and the outer sheath (12).

9. The fire-prevention early warning computer cable according to claim 1, characterized in that, The C-shaped elastic ring (23) is made of beryllium copper, and the phase change material is a composite of paraffin and expanded graphite. The thermally induced deformation unit also includes a fixing bracket, which is installed inside the housing (13) to support the C-shaped elastic ring (23).

10. The fire-prevention early warning computer cable according to claim 1, characterized in that, The number of thermo-deformation units is one every 1.5 to 2.5 meters.

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