The basic principal of an Infrared (IR) Dryer is to penetrate the web with heat and dry it from the inside out.

IR dryers locate an electrical or gas powered radiant heat source immediately above the web. By operating at very high temperatures, the heat source quickly raises the temperature of the web as it passes. By driving up the temperature of the web, moisture on the surface warms to the point where evaporation can occur.

The substantial heat required to raise the web temperature makes this process very inefficient. Much of the heat energy is lost to the surrounding environment. In addition there is no means for breaking down the boundary layer on the surface of the web, which in turn limits the rate at which moisture can be released from the web.

Advantages:

  • Familiar Technology – Converters are comfortable with this technology and know what to expect when using it.
  • Raises Web Temperature Quickly - Excellent process for quickly raising the temperature of the web in a short distance.

Disadvantages:

  • Inefficient Process for Heating the Web – Much of the heat energy is lost to the surrounding environment.
  • Poor Evaporation Rates– IR technology does not breakdown the boundary layer on the surface of the web so that moisture can be freely released.
  • Non-Hazardous Applications Only – The heating element is exposed to the environment limiting this technology to non-hazardous applications
  • High Web Temperatures – A tremendous amount of heat is delivered to the web, which may cause difficulties in maintaining registration.
  • Web Burns - The web is susceptible to burning during press stops.
  • High Operating Costs – Heating elements require a tremendous amount of power to achieve the required operating temperatures.
  • High Heat Loads to the Plant Environment – Since these dryers systems operate at such high temperatures, a tremendous amount of heat radiates from the dryer housings.