In most industrial processes, the accumulation of static charge is generated, which makes people feel uncomfortable and causes harm to the human body. Fire and explosion accidents can occur even during handling and transportation of flammable gases, liquids and dust. The belt conveyor line is no exception. Therefore, it is necessary to take precautionary measures against static electricity. Let us talk about how to do the static protection of the belt conveyor line.

  There is no static hazard control method that can be applied to all industrial processes or situations, and sometimes two or more types of belt line electrostatic hazard prevention methods are used at the same time.

  (I), grounding In the electrostatic hazard prevention method, grounding is the most effective and economical method. During the process, static electricity is generated by friction, induction, or conduction. If the charge accumulates on a metal device, a conductive product, or a person's body that is insulated from the ground, the accumulated charge will release the energy in one discharge. Such electrostatic discharges from conveyor line manufacturers are the main cause of electrostatic hazard accidents. The prevention method is to ground all the conductive objects and maintain a low grounding resistance, and the electric charge accumulated on the metal equipment, the conductive products or the human body is quickly dissipated to the earth to avoid an electrostatic hazard accident.

  According to relevant research, in the general workplace where flammable vapor exists, the potential of the insulated metal equipment/component, conductive product or personnel body itself needs to reach 100V or more, which may ignite the surrounding flammability due to discharge. substance. Therefore, in the factory, the insulated metal equipment/components, conductive products, etc. are grounded, and the grounding resistance is less than 106Ω, which is enough to dissipate the accumulated electric charge to the ground quickly, and reduce the electrostatic potential to below 100V to avoid An electrostatic hazard has occurred.

  (II) Increasing Humidity Increasing the relative humidity of the air in the working environment is also a common method for preventing electrostatic hazards in the current manufacturing process of traditional industries. In the high humidity (RH > 65 %) environment, if the surface of the material is hydrophilic, it is easy to adsorb the moisture in the air, thereby reducing the surface resistance of the substance, increasing the rate of charge dissipation, and minimizing the charge accumulation. . Such materials include cotton, paper, and cellulose acetate. In the factory process, humidifiers, ground sprinklers, or steam ejecting are usually used to increase the relative humidity of the air in the working environment. If the surface of the substance is non-hydrophilic, it is difficult to adsorb moisture in the air, so that the surface resistance value of the substance cannot be lowered, and thus the rate of charge dissipation cannot be increased. Such materials include partially artificial polymers such as ABS (Acrylonitrile - Butadiene - Styrene, propylene laurel - butadiene - styrene), Teflon (Teflon, fluorocarbon polymer) and the like. Such highly water-repellent substances need to increase the relative humidity to 80% or even more than 90% in order to effectively reduce the surface resistance of the substance and minimize the accumulation of charge.

  (3) Antistatic materials The static electricity accumulated in the process will be dissipated to the earth through the conduction path. When the conduction path is an insulating material (low conductivity), the static electricity dissipation rate is low, and if the conduction path is a conductive material (high conductivity), the static electricity dissipation rate is high. If the surface resistivity of the substance is less than 1011 Ω/m 2 or the volume resistivity is less than 1010 Ω/m 2 , excessive accumulation of static electricity can be avoided. This type of substance is called an antistatic material. However, in workplaces containing flammable substances, the surface resistivity of the antistatic material should be less than 108 Ω/m2 or the volume resistivity should be less than 106 Ω/m2. For various materials used in industrial processes, they can be made into antistatic materials by the following methods: the materials themselves have antistatic properties (such as cotton, wood, paper, soil, etc.), and antistatic substances are coated on the surface of the insulating materials. (such as carbon powder, antistatic agent, etc.), adding conductive or antistatic substances (such as carbon powder, metal, antistatic agent, conductive fiber, etc.) in the manufacturing process of insulating materials.

  (4) Static Eliminator The use of high voltage electricity to generate charged ions in the air. Since the opposite charges are attracted to each other and neutralized, the ions neutralize the charge of the electrostatically charged object, minimizing the amount of charge accumulation, so that electrostatic discharge does not occur. Static eliminators can be roughly classified into three types: passive, active, and radiation source. When selecting a static eliminator, the operating environment factor must be considered to maximize the static elimination. In general, the static eliminator should be placed close to the electrostatically charged object away from the grounded metal object to maximize the static elimination effect. In addition, attention should be paid to industrial hygiene problems caused by ionization and industrial safety problems caused by short-circuit and discharge of high-voltage power supplies and charged bodies.

  (V), speed limit In the industrial process, two kinds of objects may generate static electricity due to friction, and gradually accumulate and cause electrostatic hazard accidents. Therefore, reducing the friction speed can slow down the generation of static electricity and achieve the purpose of preventing electrostatic hazard accidents. In the industrial process, it is limited by the material characteristics and production requirements, and the speed hazard prevention method is usually applied to the transportation of flammable liquids. When transporting liquid raw materials/containers to storage tanks or containers, if they are flammable liquids with low conductivity (less than 50 pS/m) and contain incompatible substances such as suspended solids and water, they should be flammable when working in the field. The liquid flow rate is below 1 m/s. If the flammable liquid does not contain incompatible materials, the liquid flow rate should be limited to less than 7 m/s. General industrial processes can be based on this principle for process design and production operations. Leakage caused by low conductivity flammable liquids is one of the potential sources of electrostatic hazards in the process. The liquid feed line can be as close as possible to the bottom of the tank/container, or the liquid raw material can be transported from the feed line at the bottom of the tank/container, or the flow rate of the flammable liquid can be reduced, mainly to reduce the passage of liquid through the liquid level. The friction and the disturbance of the liquid to avoid generating a large amount of static electricity due to excessive friction.