Anti-static container bags are also called conductive container bags. According to the degree of electrostatic ignition hazard and their internal structure, they can be divided into four categories. This classification method is widely used by many people in Europe. In June 2003, the European Committee for Electrotechnical Standardization CENELEC published the document CLC/TR50404 "Electrostatics-Code of Practice for the avoidance of hazards duo tostatic electricity". This is a very comprehensive standard for electrostatic operation in various fields of industry. There is a chapter that points out the rules for the safe use of container bags in more detail. The standard divides FIBC into four categories: Type A, Type B, Type C, and Type D.
Type A anti-static bulk bags have no special electrostatic safety features. Therefore, they are not recommended for the treatment of sensitive flammable dusts and powders. In addition, they cannot be used where dust clouds or flammable solvent vapors are present. This type of FIBC is usually woven with ordinary woven polypropylene cloth and is an insulator. Sometimes, according to the requirements of use, the Type A container bag will use inner liner bag or surface coating treatment.
Type B anti-static container bag is similar to Type A, and is also made of ordinary woven polypropylene cloth. However, the breakdown voltage of the woven fabric of Type B bags cannot be higher than 4KV. This means that Type B bulk bags will not produce propagation-type brush discharge. This is an important classification, that is to say, few discharges that can be produced on the bulk bag are low-energy brush discharges. If the propagation type brush discharge can be excluded, and the super energy of the brush discharge is 4mJ, there is reason to believe that this type of container bag is safe for the combustible gas environment with ultra-small ignition energy not exceeding 4mJ. Similarly, for combustible dust whose ignition energy does not exceed 4nd, this type of container bag is also safe. However, Type B bulk bags cannot be used in flammable hydrocarbon vapor environments. It must be noted that some factory-made FIBCs meet the Type B classification standard, but they can still cause accidents. For example, when tested by a testing organization, it meets the Type B standard. However, in actual use, the breakdown voltage is higher than 4KV due to the surface coating of the inner bag and the bag body, which makes the Type B bag actually It became Type A.
Type C antistatic container bags are designed for sensitive and flammable environments, including flammable hydrocarbon solvent vapor environments. This type of container bag is made of conductive cloth or woven cloth coated with conductive/anti-electric coating. Conductive cloth is actually a woven cloth interwoven with conductive fibers/flat yarns. In some designs, the conductive wires are parallel and the spacing is 20mm. There are also designs that woven conductive silk into a network, and the silks intersect perpendicularly. The conductive wire is usually a conductive flat wire or a conductive metal wire.
Type D conductive container bag has anti-static or static dissipative properties and does not need to be grounded. Most Type D FIBCs on the market are made of thin semi-conductive threads interwoven into woven fabrics. Unlike the design of Type C FIBC, these semi-conductive wires are parallel but not cross-linked. This type of FIBC may have static elimination coating, so we usually call Type D FIBC as conductive FIBC. Due to its complicated manufacturing process, the price will be 20% higher than the above three types. about.
