Flame-retardant and fire-resistant DC power cable for rail transit, and manufacturing system and method

Abstract

The invention discloses a flame-retardant and fire-resistant direct current power cable applied to rail transit and a production system and method. The cable comprises a stranded conductor, a fire-resistant insulation layer, a flame-retardant insulation layer, a water-blocking layer, a flame-retardant and fire-resistant waterproof isolation layer, an armor layer and a flame-retardant outer protective layer. The flame-retardant and fire-resistant waterproof isolation layer comprises an inner longitudinal package aluminum-plastic composite belt, and an outer flame-retardant and fire-resistant polyolefin cover. The longitudinal package aluminum-plastic composite belt and the flame-retardant and fire-resistant polyolefin cover are spliced and combined into a composite integral structure. The stranded conductor is formed by stranding annealed copper wires into a regular stranded conductor or soft conductor of 50mm<2> to 400mm<2>. The fire-resistant insulation layer is formed by wrapping double-layer ceramic fireproof and fire-resistant silicone rubber composite tapes on a wrapping device in an overlapped manner. An ultraviolet light irradiation crosslinking halogen-free low smoke flame-retardant polyolefin insulation material is extruded on an insulation extrusion crosslinking production device to form a coating structure. The cable provided by the invention has the advantages of high flame-retardant and fire-resistant ability, good insulation performance, great fire resistance and high cable production efficiency.

Description

technical field [0001] The invention relates to a direct-current power cable used in a direct-current traction power supply system of urban rail transit, in particular to a flame-retardant and fire-resistant direct-current power cable for rail transit and a manufacturing system and method. Background technique [0002] The rapid development of urban rail transit has greatly alleviated the situation of urban traffic congestion, and at the same time put forward higher requirements for the safety and reliability of urban rail transit operation. Urban rail transit DC traction power supply system is an important part of urban rail transit, it provides reliable power and electric energy for the safe and stable operation of urban rail transit. As the transmission channel of traction electric energy, DC power cables directly affect the safety and reliability of subway vehicles and even the entire system. In addition, DC power cables are mostly used in densely populated underground ...

AI Technical Summary

Problems solved by technology

Its defect is that when a fire occurs, although the sheath of the cable can delay the burning and spreading speed of the entire cable, when the fire continues to burn, it will break through the sheath and ignite the insulation, causing the cable to short circuit and fail to work.

(2) The refractory layer of traditional fire-resistant cables is generally wrapped with high-priced refractory mica tape. The wrapping speed is slow, and the mica powder is easy to fall off during the wrapping process, which affects the fire-resistant effect; Brittle, easy to fall off when encountering vibration and spraying, poor fire resistance effect, it is difficult to ensure that the power line can still be safe and smooth in the event of a fire

(3) The refractory layer of some fire-resistant power cables is made of ceramic fire-resistant and refractory silicone rubber. The processing technology is: vulcanization→extrusion→vulcanization. The extrusion process requires a special silicone rubber wire and cable extruder to complete. Vulcanization also requires special vulcanization equipment, such as: hot air vulcanization furnace, microwave vulcanization oven, etc. The processing technology of the refractory layer is complex and the production efficiency is low

(4) The fire-resistant cable structure of the prior art is only designed with one layer of refractory layer, which is coated on the outside of the conductor. Although the structure is simple and the processing technology is simple, when a continuous fire occurs, the flame breaks through the outer sheath until only the refractory layer is left. As the last protective layer of the cable, the refractory layer is extremely vulnerable to external damage, including vibration, mechanical damage or artificial damage, resulting in a short fire-resistant time and poor fire-resistant effect of the cable.

(5) Some fire-resistant cables use multi-layer fire-resistant layers. Although the fire-resistant effect is good, special processing equipment is required to increase the processing procedures. The processing technology is complicated and the processing efficiency is low.

The warm water cross-linking method needs to put the entire cable core into a special warm water cross-linking pool for at least 5-8 hours / time after the cable insulation layer is extruded to meet the requirements. The size of the joint pool is related to the size of the joint pool, which occupies a large area and the cross-linking speed is slow, resulting in a long cable processing time; steam cross-linking needs to put the entire cable core into the steam cross-linking room to heat after the cable insulation layer is extruded, and cross-linking The speed is improved compared with the warm water cross-linking method, but it is also affected by the limitation of the occupied area, it is difficult to carry out cross-linking in large quantities, and the cable processing time is delayed

Images