Plastic check valve is a valve, which is designed to give accurate, leak-proof security and is installed anywhere in the airline. It protects the air pump from back-siphoning damage, and prevents flooding during power failures.
Plastic coating is the process of applying a thermoplastic to the surface of metal items to provide long-term corrosion, impact and chemical resistance whilst offering an attractive decorative finish. The paper backing for mailing labels is an example of plastic coated material. One method of coating a substrate with plastic is extrusion laminate coating. In this process, a thin film of plastic is extruded, and then simultaneously fed into a set of rollers along with the substrate. Depending on the plastic material and the substrate, the plastic need to be heated to accomplish adhesion, or the surface of the substrate need to be treated with a chemical solvent to force bonding of the plastic. Thinner coatings use plastic coating materials of low viscosity and the rollers turn together & for thicker coatings and high viscosity materials, the rollers turn in opposition to each other.