Cost considerations and selection
Generally, you can consider which mica tape to purchase according to the design standard, product unit price, etc
(1) Phlogopite tape
A: Three in one phlogopite tape: all mica tape products have the lowest price and good insulation performance, so they are the main choice;
B: Single side phlogopite tape: it is economical to use, but the price is on the high side, and the wrapping speed is slow, so there are few choices;
C: Double faced phlogopite tape: The product quality is the most stable, but the price is the highest, and there are few choices.
(2) Synthetic mica tape
A: Three in one synthetic mica tape: the lowest price among synthetic mica tapes, with good insulation performance, is the main choice;
B: Single side synthetic mica tape: the price is high, and the wrapping speed is slow, so there are few choices;
C: Double sided synthetic mica tape: it is the most stable product, but it has the highest price and few choices.
(3) Calcined muscovite
A: Three in one calcined mica tape: the calcined mica tape has the lowest price and good insulation performance, so it is the main product of choice;
B: Single side calcined mica tape: the price is high, and the wrapping speed is slow, so there are few choices;
C: Double sided calcined mica: it is the most stable product, but the price is the highest and there are few choices.
Selection of wrapping method
The mica tape is wound onto the copper conductor, which can be divided into single coil winding and tower winding according to different winding machines
Single coil winding: single coil mica tape
Tower winding: select tower tray mica tape
Selection of fire resistance temperature causes
According to the original national standard, the fire resistance rating is divided into Class A and Class B:
Class B fire-resistant cable: withstand combustion for at least 90 min under 750 ℃~800 ℃ flame and rated voltage without breakdown (i.e. 3A fuse is not blown);
Class A fire-resistant cable: withstand combustion for at least 90 min under the flame of 950 ℃～ 1000 ℃ and rated voltage without breakdown (i.e. 3A fuse is not blown);
Although the national standard cancels the classification grade, this classification method is still used in key projects. Therefore, Category B will use phlogopite tape and Category A will use synthetic mica tape.
Our industry is designed to reduce fire accidents and start fire fighting and emergency rescue facilities in case of fire accidents, so as to save more lives and reduce all losses.
In recent years, with the increase of major loss of life and property caused by medium and large fire accidents in China, China has a deeper understanding of fire protection and fire safety. According to statistics, from 11 to 16 years, there were more than 520000 electrical fires, accounting for more than 30% of the total national fires and casualties. However, the fire caused by aging and overload use of wires and cables accounts for a large proportion, and the fire accident is further expanded because the combustible insulation and sheath materials in wires and cables are ignited during the fire. If the power line leading to the fire fighting equipment is burnt, it will interfere with the normal operation of relevant equipment, delay the fire fighting time, and cause greater loss of life and property.
How to ensure the smooth flow of power and communication within a certain period of time in case of fire to maximize the valuable rescue time to reduce casualties and loss of life and property is a subject that people have been constantly exploring.
The fire-resistant cable is a series of cable products formed according to IEC60332 series standards. It can work continuously for 90 minutes in the 800 ℃ fire field, and can meet the application requirements of various fire alarm and fire prevention equipment in the current buildings.
The application value of fire-resistant cables is to provide electrical energy or control signals (electrical signals) for equipment and systems in the fire site, and create conditions for these equipment and systems to work after the fire according to the fire prevention specifications in buildings. The reason why fire-resistant wires and cables are widely valued is that they have two main characteristics:
The fire-resistant cable can maintain the normal operation of the line for a certain period of time, and is mainly used in important occasions where the normal power transmission must also be ensured under fire conditions. In general, the fire-resistant cable can ensure that the cable continues to operate within a certain period of time after the fire, maintain the normal power supply of the lighting, emergency broadcast, fire alarm device, automatic fire fighting facilities and other emergency equipment in the channel, so as to transmit various control signals, facilitate the timely evacuation of personnel, and ensure the normal rescue work.
Second, it can restrain the fire caused by short-term overload. The fire-resistant cable can effectively isolate the fire of its insulation layer caused by the self heating of conductor overload within a certain period of time, thus reducing the chance of fire.
In 1980, the mica tape wrapped fire-resistant cable was first applied to the British North Sea offshore oil platform. This type of fire-resistant cable began to be widely used with the advantages of simple process, low price, and unaffected production length and scope of use. This kind of fire-resistant cable is generally composed of conductor core, fire-resistant layer and insulation layer. Copper conductor is directly wrapped with fire-resistant mica tape as the fire-resistant layer. Its "fire-resistant mica tape" can be sintered into a hard and dense insulating material attached to the conductor surface after being exposed to fire, so as to ensure the normal operation of the line under fire conditions.
Note: There are generally two types of mica tape: fire-resistant mica tape and motor mica tape. The mica tape mentioned in this manual refers to "fire-resistant mica tape".
Manufacturing process and fire resistance characteristics of mica tape
After the glass fiber cloth is coated with organic adhesive, it is compounded with mica paper. The organic adhesive penetrates into the mica paper to bond the mica paper and glass cloth, and then it is baked (the three in one area also needs to be coated) and cut into mica tape.
Mica is a kind of silicate mineral. Its main component is silicon dioxide. It has good insulation performance under high temperature. The mica paper produced will have certain voids or micropores. When it is bonded with glass fiber cloth with adhesive, the adhesive will penetrate into the voids or micropores. At the flame temperature, the organic matter and part of the silicon powder will decompose and volatilize (emit white smoke) to form sintered silicon powder (that is, form ceramics like), However, due to the extremely low carbon content in the silicone adhesive, the residue after high temperature action still has high electrical insulation performance.
The main products of fire-resistant mica tape produced by our company are: phlogopite tape, synthetic mica tape and calcined muscovite tape.