Liquid Coating Ovens

 
 

Solvent based and waterborne coatings are the most common coatings used in industrial finishing today. The coatings provide for simple, effective, and efficient application and finish. Additionally, waterborne coatings are also quite environmentally friendly. But the carrying agents, whether solvent or water, must be removed in the drying and curing process, requiring not only the transfer of heat to the part and coating, but significant mass transfer as well. Therefore, the design of an oven to rapidly and accurately dry and cure liquid coatings is not just a simple task: It is an engineering challenge.

Coated products come in a variety of materials, shapes and sizes. Coating formulation and application also directly affect the oven design. Therefore, the oven must be designed to ensure consistent and precise control of temperature, heat intensity, and airflow as well as material handling and process control.

And more importantly today, as your formulations change to deliver the quality and environmental compliance you require, the oven must be designed to provide the flexibility to meet your everchanging needs. From solvent based to waterborne to high solids and even powder coatings, Thermovation Engineering ovens can meet your everchanging needs.

The optimum solution for drying and curing liquid coatings are often not just hot air ovens. The solutions may be ovens designed to capitalize on all of the beneficial characteristics of the two most common and effective process heating technologies available–infrared and convection heating. We call these solutions combination ovens.

To properly dry and cure liquid coated parts, an oven must provide at least one, and in most cases two, distinctly different heating phases. The first and most critical phase is the mass transfer stage, or drying stage. In simple terms, the solvent or water must first be removed before the second phase, the curing stage, can begin.

In more complex terms, the oven must initially supply thermal energy to the part and coating until the vapor pressure of the liquid carrying agent, whether solvent or water, is higher than the vapor pressure of the carrying agent in the air surrounding the coating. The thermal energy supplied to the coating increases the vapor pressure of the carrying agent. Thermal energy supplied to the air surrounding the coating concurrently reduces the relative humidity of the air, thereby increasing its ability to absorb vapor. Again, the removal of the carrying agent is called mass transfer. Then once the carrying agent has been removed, the part and coating must be raised to and accurately maintained at the required curing temperature for the period of time specified. Most liquid coatings, but not all, require this additional time, or second phase, to complete the cure.

Thermovation Engineering follows a systematic approach to the design of liquid coating ovens. We thoroughly analyze your needs and constraints, and then design an oven, handling, and control system that will operate efficiently and effectively to produce the optimum coating characteristics you desire at the lowest possible cost. Our results can be seen in motors from Lincoln Electric to lighting fixtures from GE.

We know that no single heating technology, whether gas or electric, infrared or convection, can alone meet the complex and changing requirements of today's liquid coatings. Each has its own capabilities and limitations. Therefore, we design our ovens to incorporate just the right combination of these technologies to achieve the optimum results.

Our high efficiency ovens increase quality and productivity. Our ovens hold temperatures to within two degrees of the set point. And our ovens not only require less space, but cost less to operate than the systems they replace.

See also infrared, convection, and THERMODRY™; dryers.