Performance analysis of the hottest nylon sheath w

Performance analysis of nylon sheathed wire

I. Introduction

PVC insulated wires have been used for power line wiring in China for a long time. With the rapid development of economic construction and modernization, not only the number of electrical appliances is increasing, but also the capacity of various electrical appliances is also rising, which puts forward new requirements for the design of power circuit. It not only requires a large number of circuits, but also puts forward higher requirements for the quality of circuits, especially for the safety of wiring as circuits in preventing electric shock and short-circuit fire accidents. According to the information issued by the national public security department, in recent years, 30% of the shocking fire accidents, large and small, were electrical fires. This makes the prevention of wire short circuit accidents become the primary problem to be solved urgently in design, construction and decoration. According to the analysis, the short circuit of building cloth wires is due to the following reasons: the wires are aging, the wires scratch the insulation in the pipe, forming potential short-circuit hazards, the lines are overloaded, the temperature exceeds the specified range and the insulation is burnt out, and many disastrous fire accidents have aroused great concern of the whole society. Since 2001, in the column of "building wire promotion project" in the "International Copper Association injection mold cooling circuit structure is also a key meeting in mold design (Beijing)", experts have continuously carried out extensive and in-depth discussions on electrical design issues

II. Propose the premise of FVN nylon sheathed wire products

III. with people's great attention to the prevention of fire accidents, it can be expected that for power wiring, experts will seek a new product with superior performance to replace it. This is not only the improvement of electrification level, but also reflects the country's high attention to the value of people's lives. In 1997, China's wire and cable industry and Shanghai Cable Research Institute introduced American technology to research and develop PVC insulated nylon sheathed wires and cables with rated voltage of 450/750v and below. Some domestic enterprises with faster understanding then developed and produced the new wire. In 2000, the Ministry of construction of the people's Republic of China listed the FVN product in the guide project for the promotion and transformation of scientific and technological achievements to promote its use. In May, 2001, China Machinery Industry Federation approved and issued jb/t PVC insulated nylon sheathed wires and cables with rated voltage of 450/750v and below. This can be described as a three-step process of FVN type wiring on the stage in China

why does nylon sheath wire become a substitute for PVC wire? We can see from the domestic and foreign use of this half century that the United States is a highly developed capitalist country, and its science and technology have always been at the international leading level. As early as the 1950s, nylon sheath wire has been widely used in all kinds of buildings and family houses, and it is still enduring. In some countries in the 1970s, FVN wire was only used in some aircraft, automobiles, power systems and control systems, which shows that FVN wire has unique advantages over PVC wire

IV. advantages of FVN wire

after repeated tests and long-term practice, experts have summarized the following seven advantages of FVN wire:

1 It is convenient to thread pipes. The diameter of the wire is thin, and the friction coefficient decreases significantly when passing through the pipe

2. The threading capacity of wire conduit is increased. The diameter of the wire is small, and there are many wires or large current carrying capacity that can be penetrated into the conduit of the same size

3. Excellent wear resistance reduces the damage to insulation when wires are threaded and laid. This is very important, which can effectively reduce the hidden danger of potential short-circuit accidents

4. Excellent hydrocarbon resistance and good chemical stability, that is, excellent oil and liquid resistance, including and complying with the verification regulation of extensometer, the corrosion performance of chemical gas and gas, which effectively improves the reliability and service life of the distribution wire (aging performance test shows that the service life of FVN type wire is at least twice that of the original PVC type wire, that is, 40 years or more)

5. High safety performance. Through the test, FVN type wire has good thermal stability and heat shrinkage resistance. This will help to avoid the possibility of short-circuit fault caused by overheating of the grounding point, which causes the insulation shrinkage of the wire and exposes the copper wire

6. It has the ability to withstand considerable short-circuit current, and the short-circuit withstand temperature for 5 seconds is higher than that of ordinary PVC type. This is because of the nylon sheath, and the melting point of nylon is 215 ℃

7. It has the same flame retardant performance as PVC insulation. According to the test of relevant experts, the toxicity released by its combustion is far less than that of PE

8. The manufacturer's name, product model, voltage level and other marks of the wire drawing fixture are printed between the PVC insulation and the nylon sheath, and the marks are clear and abrasion resistant

v. comparison of material structure between FVN wire and PVC wire

fvn refers to China's mechanical standard jb/t, namely PVC insulated nylon sheathed wire and cable with rated voltage of 450/750v and below, while bv refers to the national standard GB 5023, namely PVC insulated cable with rated voltage of 450/750v and below. Here we might as well take it out for comparison. (for details, please refer to the standard and omit here). The structure shows that the material cost of FVN is slightly higher than that of BV wire, and the processing is slightly complex, so the price of FVN is slightly higher than that of BV wire

VI. comparison of equipment investment

the equipment used to process FVN wire and bv wire is not much different. Extrusion machine is used to press out, and there are slight differences due to the different processing properties of nylon: 1. Processing temperature: Nylon processing temperature is about 220 ℃, while PVC is between 160 ~ 180 ℃; 2: Thin wall extrusion: the thickness of bvn nylon sheath is 0.1 ~ 0.15mm, so the extruder below ∮ 45mm is generally used; 3: Extrusion screw: due to the different fluidity between nylon and PVC, in order to stabilize the extrusion, it is best to use a special nylon extrusion screw. However, the overall production equipment of nylon sheath line is similar to that of ordinary PVC extruder

VII. Remaining problems and prospects

fvn wire has so many advantages, which is an important reason why it will inevitably replace bv wire. However, FVN wire has not been widely used in recent years, and the analysis is nothing more than the following reasons:

1 FVN products have not been familiar to people, the publicity of relevant aspects is not enough, and many advantages are not understood by users

2. The domestic FVN wire product standard has not been promulgated for a long time, and the country has not yet listed it as a mandatory standard

3. For a long time, users are used to purchasing and using bv type wiring

the cost of type n is slightly higher than that of BV

however, it can be expected that with the promulgation and implementation of the FVN product standard, this new type of product will soon be accepted by users. At present, some large buildings (such as Olympic venues) in big cities such as Beijing and Shanghai have required the use of FVN type cloth wires. It is widely used in Europe, the United States, Canada, Canada and the Middle East instead of composite products. In the foreign market, this FVN type wire with nylon sheath occupies more than 95% of the cloth wire market. Although China has just started, it has bred a huge market. (end)