The operating principle in this oven is a combination of a perforated drum with a large centrifugal fan. The fan aspires the air from the center of drum, then it passes through the heating system (normally gas burner) and is forced back to the drum. This generates a vacuum within the drum on which surface the material is held. So, the material is traversed by a large volume of the hot air  which  ensures high heat transfer. The material to be treated is in intimate contact with the heating medium, guaranteeing high efficiency and optimum capacity.

When using these machines for thermal stabilization, it is possible to add two crowns of pins (adjustable) at the edges of the drum, in order to hold the felt during heating. The pinned crowns can be set at different positions via motor and display, from the control board.

The drum dryer is equipped with a high-pressure & vacuum fan which forces a large volume of the air through the material, even though webs with heavy weights. By installing a variable speed motor on the fan, the line performance can be adapted to suit material qualities with different air permeabilities.

Heating via gas burners gives a reduced warming up and cooling time, providing high efficiency and accurate temperature regulation due to the flame modulating system, driven with a P.I.D. controlling device. After the drum oven, acooling drum could be installed and an oil heated calender (for smoothing and thickness adjustment). Due to the complete penetration of the air throughout the nonwoven product, these ovens are extremely efficient and require reduced floor space. The drums diameter is optimized accordingly with the speed and the application, and they can vary from 1,4 to 7,5 meters with speeds up to 800 m\min. There is also the possibility of adding more than one drum in line  to achieve faster speeds or having the drum one on top of the other (vertical oven).

When the web width changes, it also possible to install  adjustable shutters that stops the passage of air on the sides of the web.  This is to avoid loss of efficiency and optimum performance.

Possible to equip with energy recovering system. When drying, these ovens result compact and extremely efficient because forces a great volume of hot air through the web, in reduced space and short time.

Following the production type, the drum surface could in perforated steel, fine mash net welded on the drum, converjor belt.

Typical applications of these ovens are:

• Drying of chemical bonded felts
• Thermal stabilization of technical felts
• Drying of spunlaced webs