The Primary Components of an Impingement Dryer – Part 2

In this post we continue and finish the discussion of the primary components of an impingement dryer.

Impingement Nozzles and Supply Plenums

The design and fabrication of the impingement nozzles and supply plenums are very important to the drying effectiveness and uniformity. Characteristics of good design include the following features:

Exhaust and Recirculation Air Collection

As noted in the previous section the means to which the exhaust and recirculated air is removed from the web is important to the uniform heat transfer to the product.

Interconnecting Ductwork

Exhaust Fan

All dryers are required to have exhaust. This is used to help keep the dryer negative to the room it resides in and to remove the solvent, whether water or a VOC. Characteristics of the exhaust fan should include the following:

Web Support

In horizontal impingement dryers the web must be supported as it travels through the dryer. This is typically done with idler rolls. In some cases the rolls are arranged in an arched configuration and in some cases they are flat. Though some textile and metal coil webs can be greatly tensioned and avoid the need for support in the dryer this is not typical for most impingement dryers.