Dillman UniDrum® Counterflow Dryer/Drum Mixer

The Dillman UniDrum mixer offers asphalt pavement producers a heavy-duty drum that generates high quality mix.

Dillman has years of experience building heavy-duty equipment for the asphalt pavement industry. The Dillman unified drum is a high quality counterflow design that is offered in both portable and stationary arrangements. The UniDrum mixer is offered as part of complete new plants and also for retrofit applications, with a range of production capacities from 200 to 600 tons per hour (182 to 544 tonnes per hour) with 5% moisture.

Features & Benefits

  • Portable and Stationary available
  • Range of capacities from 200 to 600 TPH
  • Can process mix with up to 50% RAP
  • V-Flights produce a more even aggregate veil to facilitate heat transfer
  • Single-Point Trunnion Alignment saves time and ensures proper equipment operation

The Dillman UniDrum is unique among competitive products with the ability to produce a high quality mix while requiring minimal maintenance.

The massive trunnion minimizes wear to the tire.
Adjust the trunnion in a matter of minutes without the need of any specialized equipment.
Aggregate belt slinger.
Dust entry to UniDrum from baghouse.

Stationary And Portable Configurations

Need the quick setup and mobility of a portable plant, or the flexibility and operating capacity of a stationary? The UniDrum mixer can be configured for either portable or stationary plants.

Extra Long Drum

With an extra long drum, the Dillman UniDrum mixer is uniquely capable of producing quality hot mix at a high production rate with a high percentage of recycle. The extra long drum length maximizes mixing and drying times to reduce fuel consumption and provide superior mixing.

Single Point Trunnion Adjustment

This system eliminates the time-consuming procedure of trunnion alignment and ensures proper equipment operation. Centered around a massive 20” (50.8 cm) trunnion, fitted with adjustable double-row Timken™ bearings and ring fitters, this system is an industry exclusive. The key is our unique pivot pin system, which allows the asphalt contractor to easily dial in the dryer in a matter of minutes without the need of any specialized equipment. The end result … a properly rotating dryer without excess wear to the tires, trunnions and thrust roller assemblies. With the single point trunnion adjustment you can significantly reduce excess trunnion wear, premature deterioration of hardened tire surfaces, broken trunnion shafts, bearing failures and thrust roller assembly damage.

The Dillman UniDrum features a quality design and heavy duty construction which delivers an excellent mix.

RAP is quickly brought up to temperature when it instantly mixes with the hot aggregate.
Dillman adjustable flights allow you to better control moisture removal from aggregate.
An optional warm mix system saves energy without losing mix quality.
The UniDrum is outfitted with Astec’s Whisper Jet® or Phoenix® Talon burners.

Patented Flighting Design

Dillman flights are adjustable to better control the baghouse temperature and moisture removal from the aggregate.

Heavy Duty Support Structure

The supports are produced by certified welders using heavy, structural I-beams. The heavy I-beams achieve a high safety value. The supports also provide rigidity and stability to the entire drum unit, which minimizes maintenance.

Unique Recycle Entry

The inlet into the drum allows immediate mixing of recycle with the hot aggregate, bringing the recycle up to temperature and removing any residual moisture. Clean-outs in the collar around the drum allow for easy maintenance.

Optional Warm Mix System

An optional warm mix system saves energy and eliminates smoke and emissions without compromising mix quality. The system uses water to produce a foamed asphalt that is odorless, smokeless and longer lasting. The injection of water with the liquid asphalt cement causes the liquid asphalt to foam and expand in volume without the addition of costly additives. The foaming action helps the liquid asphalt coat the aggregate at a lower temperature.

Optional Liner Package

1/2” Hardox® liners reduce wear and help extend the life of the drum and flights.


Inside Drum

  1. An Astec long nosed burner plays an integral role in the mix production process.
  2. Recycle inlet.
  3. Virgin material enters the drum and flows through the drum counter, or opposite to, the hot gas stream produced by the burner and the exhaust fan.
  4. Mixing flights.
  5. Combustion flights.
  6. Flights with heat shields.
  7. Flights with doors.
  8. Sawtooth flights.

Outside Drum

  1. Liquid asphalt cement entry.
  2. Thick insulation under the stainless steel shell helps prevent heat loss.
  3. Recycle entry.
  4. Extra long drum length maximizes drying time to reduce fuel consumption and provide superior mixing.
  5. Final mix exits via a discharge chute to the silo drag conveyor.
  6. Single point trunnion adjustment.
  7. Heavy duty support structure.
    Sawthooth flights begin the aggregate veiling process, bringing the aggregate up to temperature and taking the moisture out of it. The sawtooth flights help create a curtain of aggregate through the heat which helps eliminate hot zones through the length of the dryer.
    Adjustable doors help control the baghouse temperature. Close the doors for less veil and a higher temperature, or open the doors to open the veil and lower the baghouse temperature.
    As the aggregate moves closer to the flame, flights with heat shields continue to veil the aggregate while protecting the drum shell from heat degradation.
    Combustion flights prevent aggregate from impinging on the flame while spreading the material for maximum radiant heat transfer.
    Recycle material enters the drum and immediately mixes with the hot aggregate.
    After the virgin and recycled materials are combined and at the proper temperature, liquid asphalt is injected. Mixing flights provide increased agitation for improved mix quality.