With the changeover from solvent-based to water-based coatings, drying times in hot air circulation ovens have had to increase, reducing the throughput of these systems. Drying oven manufacturer, Heraeus Noblelight is currently tackling this problem by introducing infra red dryers just before the main oven. By raising the temperature sufficiently to achieve water evaporation before entry to the oven, these 'boosters' can achieve time savings of up to 50%. However, this drying performance can be improved still further by the addition of an air knife.
Using an air knife supplied by Air Control Industries, Heraeus found that by exhausting water-saturated air efficiently from the drying zone, drying takes place more efficiently, thus reducing the dwell time in the oven. The air knife delivers a continuous, even 'curtain' of air across the full width of the product and can be produced in different lengths to match the application.