Brief introduction

Special cables can withstand high temperature, acid and alkali, termite, as well as wires and cables used in ships, aircraft, nuclear power stations and other occasions. In terms of classification, it does not belong to the same classification method as power, control and computer cables, that is, the cables listed above also include special cables. Generally, special cables need to establish internal control standards.
The special cable is a series of products with unique performance and special structure. Compared with the general wire and cable with large quantity and wide range, it has the characteristics of high technical content, strict use conditions, small batch size and high added value. New materials, new structures, new processes and new design calculations are often used.

classification
High temperature resistance

High-temperature resistant wires and cables are required in aerospace, rolling stock, energy, steel, nonferrous metal smelting, oil mining, electrical machinery, construction and other fields. High-temperature resistant wires and cables with long-term continuous working temperature of 125 ℃, 135 ℃, 150 ℃, 180 ℃, 200 ℃, 250 ℃ and above, commonly used are irradiated cross-linked polyolefin, silicone rubber, fluororesin, polyimide, mica, magnesium oxide and other wires and cables. Now introduce; Two new types of high temperature resistant wires and cables.

1. Polyether sulfone (PES) insulated wire
It has excellent heat resistance, physical and mechanical properties, electrical insulation properties, extrusion molding properties, especially the outstanding advantages of being able to continuously use at high temperatures and maintain stable performance in the environment with sharp temperature changes: the thermal deformation temperature is 200-220 degrees, the continuous use temperature is 180-200 degrees, and the UL temperature index is 180 degrees; It can withstand 150-160 ℃ hot water or steam, and will not be corroded by acid and alkali under high temperature; The modulus of elasticity is almost constant at - 100 - 200 degrees, and is better than any thermoplastic resin at above 100 degrees; The linear expansion coefficient is small, and its temperature dependence is also small; It is non-toxic, approved by the FDA of the United States, and also meets the requirements of Announcement No. 434 and 178 of the Ministry of Health and Welfare of Japan; With self-extinguishing property, without adding any flame retardant, it has excellent flame retardancy, reaching UL94V-0 (0.46mm).

2. Polyether ether ketone (PEEK) insulated wire
PEEK is an ultra-heat-resistant thermoplastic resin. The temperature for long-term continuous use is 250 ℃, and the UL temperature index is 250 ℃.
PEEK is a flexible resin with good creep resistance. It has self-extinguishing property and can meet the requirements of UL94V-1 (thickness: 0.3mm), 94V-0 (thickness: 1.5mm) and 94V-5 (thickness: 3.2mm) without any flame retardant.

Special structure

1. Low inductance cable
There are strong current and weak current. Here is a kind of low inductance cable for strong current. This cable is equipped with a heat dissipation device, which is used for the connection between various contact welding machines, electric arc welding machines and pneumatic welding tongs. It has the characteristics of simple and reasonable structure, large cooling water flux, no blocking and current limiting, good heat dissipation effect, long service life, etc.
This new type of low-sensitivity cable also includes the connector fixed on the cable and the cable end, and the cable is also composed of the positive cable core and the negative cable core installed in the outer rubber tube. Because this kind of low-sensitivity cable is generally used in the occasions with voltage of 25-50V and current of 7000-12000A, the short circuit conduction phenomenon of cooling water in the cable is basically negligible, so there is no rubber hose used to isolate the positive cable core and negative cable core in this low-sensitivity cable, but a core frame with a spoke cross-section (commonly known as "plum blossom core") is specially set, The space between the "wheel center" and the adjacent "spokes" forms a longitudinal groove in the axial direction. The longitudinal groove on the core frame is the same as the total number of positive cable cores configured for the cable. The cable part is composed of the positive cable core and the negative cable core respectively placed in the longitudinal groove of the core frame and installed in the outer rubber tube. The ends of the positive cable core and the negative cable core are assembled into bundles and fixed in the cable core clamp, and then fixed on the connector. The ends of the outer rubber hose of the cable are sleeved at the end of the connector, and are tightly sealed with the tightening hoop sleeved outside the outer rubber hose.

2. Low-noise cable
Under the influence of external factors such as bending, vibration, impact, temperature change, etc., the cable with pulse signal less than 5mV generated by the cable itself is called low noise cable, also known as shockproof instrument cable. It is used for the measurement of small signals in many fields such as industry, medicine and national defense. There are polyethylene insulated low noise cables, F46 insulated low noise cables, irradiation resistant low noise cables, low capacitance low noise cables, hydrophone cables, watertight low noise cables and other types and specifications of cables.
The causes of noise in the cable include: 1) molecular friction within the medium itself; 2) Change of cable capacitance; 3) Piezoelectric effect of cable medium; 4) The friction between the conductor and the medium in the cable generates electric charge, that is, the separation of electric charge occurs when the contact between the conductor and the insulation is broken.
Low-noise cables with a thin semi-conductive layer (thickness 0.20-0.30mm) extruded on the polyethylene insulation surface have developed rapidly, and its noise value is 2-3mV. For low-noise cables working at 400 degrees, the method of wrapping high-temperature resistant semi-conductive fiber can be used to solve the problem, and its noise can reach 5mV.

Green insulation and environmental protection1. CMP cable
The cable that can pass the UL highest flame retardant grade standard is CMP cable. Dubang, Langxun and BICC jointly conducted a large number of combustion tests on wires and cables, and found that a thin layer of FEP (i.e. F46) protective layer squeezed outside the ordinary cable can meet this requirement.
Generally speaking, the low-smoke and halogen-free base material is polyolefin, which has high fuel heat and is highly flammable. Therefore, they should be mixed with metal hydrate filler to inhibit its flammability. However, after the hydration water is exhausted, it will cause fierce combustion. However, FEP has a low heat of combustion and will not burn in case of fire.

2. Halogen-free new green environmental protection wire and cable