The invention is described in the accompanying drawings, which are to show the various features of electrostatic spray coating. This application is a subsequent-in part of application Serial No. 5 72,752 filed March twentieth, 2021 and hence presently abandoned. It is the principal object of this invention to develop and produce new and improved electrostatic spray coating devices and techniques. Thus it is important for us to understand the nature of electrostatic charge that is produced due to the passage of an electric charge through a medium.
Electrostatic spray is a phenomenon where the charge of an electrically charged conductor or other electrically charged thing becomes trapped or stuck onto the surface on which it passes. This happens when the charge is formed due to the interaction of the atoms of a charged particle with the walls or surfaces of a medium. Electrostatic coatings are mainly used to mark the boundaries of parts, such as metals and circuit boards. Such applications involve application on parts that are susceptible to high voltage power or high frequency electric fields.
Electrostatic coatings are also called electrostatic insulating coatings and are usually applied over non-electrostatic surfaces to protect them. Coatings prevent the generation of electrostatic charges within the space that is coated. Such coatings can be made from materials like foams and plastics. There are many different types of electrostatic spraying systems. One of them is the non-volatile type that is made of acrylics. Another variety is that which incorporates gas such as propane, kerosene and chlorofluorocarbons.
Non-volatile and solvent-borne coatings have two major advantages. First, they do not allow passage of electricity, which means they provide safety for electrical equipments. They also do not cause ionic charge build up around the coated part, so they do not interfere with electrostatic discharge.
Solvent-borne coatings are commonly used in thermal insulation systems. The solvent acts as a conductive agent between the liquid and the metal and also acts as a solvent between the metal and the coating material. Solvent-borne coatings are generally thicker than conventional electrostatic spray coatings. In fact, it is common to find insoluble solvents exceeding 50 micrometers in thickness. It also makes the application of solvents easier.
Electrostatic sheets are widely used for several applications. The most popular of which is as electrical conductivity barrier. Such products are available in both powder and sheet forms. While powders offer a good level of electrical conductivity, sheet materials offer a good combination of strength, durability and safety.
The resistivity and electrical conductivity properties of a product depend upon the nature of the product. In electrostatic spray application, the size, shape and thickness of the particles need to be considered. There are mainly three types of these components: surface mounted, contact mounted and directed. While surface mounted and contact mounted are applied on the surface, directed is used where particles interact with one another and is therefore often referred to as a mechanical spray. Powder coated conductivity agents are the best suited for high-throughput applications.
Coatings can be made of either electrically conductive or non-conductive particles. Although non-conductive coatings are commonly used for painting, they tend to fall short when it comes to creating a strong protection barrier. The advantage of using non-conductive particles in electrostatic spray coatings is that it requires a lower overall cost. However, the disadvantage is that the particles tend to fall off easily, thus rendering it inefficient in preventing and reducing noise.
Electrostatic resistivity is defined as the resistance to electric field propagation within a space. The higher the resistivity, the greater is the energy dissipation. The electrical resistivity usually refers to a specific material’s ability to absorb or reflect electrical field, and the higher it is, the better the absorption and reflection rate. Typically, materials with higher electrical resistivity have better sound clarity and reduced echo.
As electrostatic protection is highly affected by the quality of the paint, the quality of the electrostatic spray also plays a crucial role. High-quality paints, like polyurethane and Quaternary ammonium, have a high degree of physical and chemical resistance. They are often resistant to heat, impact, abrasion, and chemical attack. To ensure the right conductivity agent for the application, it is important to use the appropriate chemicals. Some common chemical compounds used as electrostatic spray agents include urea, monomer sodium phosphate (MSP), and polyimide binder resins. The strength of these compounds varies according to the application.
Before applying electrostatic discharge equipment, it is important to prepare the work area and perform necessary safety checks. Then, the area must be totally clear of all obstructions so that the system can function properly. The last thing that an operator needs to worry about is the presence of air particles, which can slow down the reaction time of the system. This is why most industries use portable or fixed-wing electrostatic system. Lastly, it is essential to connect the electrostatic blasting head to a high-voltage power supply.