Coating Nozzle Overview – Applications & Insights

Many products that we eat or consume come with coatings. From spraying cooking oil into pans before baking cakes to applying coatings on parts to improve wear resistance, coatings provide a range of benefits. However, improper application may cause serious issues. The application may not work as intended or may leave the object exposed to damage depending on its use.

A coating nozzle allows for the application of sprays onto objects in an efficient and consistent manner. The nozzles also ensure only the right amount of spray is applied, conserving products, and lowering the amount of waste.

What are Coating Nozzles?

A coating nozzle is a spray nozzle attached to the end of flow control systems and pipes. Pipes pump the liquid into the nozzle flow system as the coating nozzle specially designed applicator applies the spray at the intended object. How the coating becomes applied depends on the equipment used, the type of liquid that is applied, and the number of products that are sprayed at once. The nozzles themselves may have different design configurations, such as air atomizing or a spray fan technique.

Additional factors to consider then deciding on the spray nozzle components involve understanding the size of the droplets that need to be applied to prevent overspray while still making an even coating, and the thickness of the coating. Also consider what type of mounting positions will the spray nozzle allow when attached to existing flow control systems. Check out the different types of coating nozzle uses based on applications.

Tablet Coating Nozzles

Tablet coating nozzles are used in the medical and pharmaceutical industries to apply an even coating around the entire tablet. For this application, the coating is typically applied to all sides, top, and underneath in one pass. One method to apply the spray may involve a fluidized bed coating, which is a system where the tablet is actually pushed into an air current where the fluid is injected into the air flow.

With the tablet suspended, the coating becomes applied evenly. Spray nozzles used in this instance must be designed to apply the right droplets at a designated rate to ensure even coverage without applying too much liquid. If too much liquid becomes applied, the tablets start to stick together.

Another type of table coating system involves the tablets being placed into a drum coating system. As the drum rotates, the tablets move around randomly as a spray bar with nozzles applies the liquid to ensure an even coating. Air atomizing nozzles are also commonly used for this application method.

Glass Coating Nozzles

Glass products are used for a number of applications, from houses, eyewear, and windshields on cars. Some glass is coated with a liquid to tint the glass in a darker shade. For other applications, a thin film is applied to protect the product while providing anti-glare and anti-reflective properties.

Glass coating nozzles may be a wide or narrow spray radius based on the size of the glass product and the type of liquid that is applied. The glass may travel under a stationary flow control system, or it may remain stationary as the spray nozzles move to apply the coating.

Food Coating Nozzles

In the food processing industry, food and food-holding applications may undergo spray coatings. Donuts may become coated with glazing, food dyes may be added to food products to make them more eye pleasing, and products could have their flavorings enhanced with spray coatings. In other instances, a preservative coating could become applied to food to keep it fresh longer. Sprays may also coat cookware, pans, or other objects to prevent food from sticking to surfaces or to prevent mold growth.

Food coating nozzles allow for the spray to freely move over the products based on thickness and viscosity. The spray nozzle also should reduce the amount of spray to preserve the spray liquid and eliminate potential waste and cleanup.

Conveyor Coating Nozzles

Conveyor belts are used in numerous industries to apply coatings. Automotive, food, medical devices, product manufacturing, metal fabrication, and many others. Products are placed onto the conveyor belt in batches as they pass underneath the flow control system.

In some setups, the conveyor system and spray nozzle system are timed precisely so that the liquid is applied as the product passes underneath. When there is a gap between one batch of products to the net along the conveyor belt, the system spray nozzle system automatically shuts off and waits for the next batch to approach the designed spray area. The conveyor belt moves continuously without stopping.

Another type of conveyor coating system involves the same setup except that the conveyor stops the product under the spray nozzle bar. The coating is applied to the product, and then the conveyor starts up again to move the next batch of products underneath the nozzles.

For continuous conveyor coating processes, flat fan nozzles are typically used that are air actuated or electrical actuated. On the other hand, stop-start conveyor systems may have cone-shaped nozzles that are air actuation or possible air atomized nozzle systems may be used for specific industries.

Mold Coating Nozzles

Molds are often used in parts manufacturing to create products such as castings, injection molding, compression molding, and other mold processes. A liquid or lubricant may be added to the mold to allow for the part to be more easily removed, or to apply certain chemicals for curing processes of the molded part.

An important factor regarding molds is the complexity of the mold. For intricately-shaped molds, the coating must be able to enter every crevice or point. For this application, mold coating processes may use air atomizing systems.

About Lechler USA's Spray Nozzles for Coating Applications

Lechler is a leading spray nozzle company providing coating nozzles for various industries. Our company takes into consideration your existing equipment setup as we design custom spray nozzle technologies that leverages and enhances your spray coating operations. We have over 140 years in of engineering experience that allows us to provide precision nozzles and nozzle systems when you want to provide various coatings. Reach out to us today to learn more.