On principle, varnish chamber dryers differ from ovens without solvent evaporation through the monitoring equipment and exhaust fan installed for this purpose.
Any influence on the temperature uniformity (on the inside) through the higherair exchange is prevented by optimum mixing with circulating air.
In the case of very high air exchange and temperatures, a heat exchanger in the exhaust air line to preheat the fresh air for the oven can be very economical.
Ovens are installed "in- line" - They heated with natural gas - indirect with a intergrated heat exchanger.
A rotatable drum on a feeding cart to charge bulk material is also feasible.