V-Pac™ Stack Temperature Control System

ASTEC's patented V-Pac™ Stack Temperature Control System allows the operator to set an optimum stack temperature for a particular mix. This system maximizes the amount of energy that goes into the mix rather than being wasted out of the stack. The system's "v-flights," unique drum flights with a deep v-shape, and its use of variable frequency drives (VFDs), which provide control of the drum rotational speed, are keys to the control system managing an asphalt plant's exhaust gas temperature and increasing thermal efficiency.


Lowers Stack Temperature on:

  • High RAP Mixes
  • Open Graded Mixes
  • SMA

Raises Stack Temperature on:

  • Virgin Mixes
  • Low RAP Mixes

Allows running SMA and high RAP mixes back-to-back with virgin mixes without flight adjustments

*U.S. Patent No. 8,863,404 B1

Astec V-Flights

V-flights provide greater uniformity of the aggregate veil during the drying process, which results in better heat transfer, a reduction of fuel use, increased productivity and longer bag life

Automatic Temperature Control

The V-Pac Stack Temperature Control System monitors exhaust gas temperatures at the baghouse inlet as the primary reference for control. As the exhaust gas temperature changes, the control system checks it against a set-point. If the temperature differs from the set-point, the control system automatically changes the speed of the drum, controlling temperature to the set-point.

Uniform Veiling of Aggregates

V-flights produce a uniform veil of virgin aggregate across the entire drum, regardless of the plant's production rate or the RAP percentage used. This enables drum speed changes to effectively control stack temperature. Since the v-flights shower uniformly without regard to material level, there is no "efficiency-robbing" hole in the veil.