Counterflow Dryer / Drum Mixer

With models ranging from 150 to 500 tons per hour, Aesco Madsen’s CFM series of counterflow dryer / drum mixers are designed to exceed the performance standards required for nearly every application. By merging counterflow technology with continuous innovation in output and efficiency, the CFM series has established itself as an industry leader in reliable, cost effective asphalt production for more than a decade.

Model Specifications

Counterflow Dryer / Drum Mixer 4

Standard Features
  • SJ2 bolt-in flights for easy replacement and veil adjustment
  • Built with heavy duty I-Beam welded construction
  • Slinger belt with reversing capabilities for easy calibration
  • Counterflow technology for higher RAP usage and lower hydrocarbon emissions
  • Compatible with all warm mix and additive systems
  • High efficiency Hauck long nose burners

Counterflow Dryer / Drum Mixer 5Each CFM Series Drum Mixer comes standard with a high efficiency Hauck Starjet Burner system. This system’s unique flame shaping feature is able to generate the ideal burner flame no matter which model CFM Drum Mixer is right for your production needs. Having this type of flame control is crucial when adjusting for variables such as aggregate composition, drum size, or environmental conditions. To provide your operation with even more versatility, the Hauck Starjet system will burn all clean commercial grades of fuel oil, natural gas, and liquid propane.

Available Upgrades
  • Hydraulic lift for quick, efficient set-up and slope adjustment
  • Stationary, Relocatable, or Portable configurations
  • Insulation wrapped shell within a durable aluminum covering to lower heat loss and burner fuel costs
  • Adjustable drum rotation speed by way of a variable frequency drive
  • Warm Mix and Anti-Strip additive systems
  • High efficiency burner capable of utilizing any type of fuel oil, natural gas, reclaimed oil, or propane

The Eco-Foam II Warm Mix system injects water directly into the asphalt cement just before reaching the drum mixer. This instantly turns the water to steam in the form of small bubbles, resulting in a “foamed asphalt” mixture. This mixture is able to effectively coat the aggregate within the drum at temperatures 50 – 60 degrees Fahrenheit lower than normal HMA due to it’s lowered viscocity. With fuel savings of approximately 2.5 – 3 percent for every 10 degree reduction in temperature, this systems return on investment for your operations bottom line will be felt immediately.

Counterflow Dryer / Drum Mixer 6

Counterflow Process

Title Test
Drying Zone

As virgin aggregate first enters the drum, it passes through the drying zone where the material is brought to temperature and any moisture is removed. This is accomplished by a series of patented SJ2 heavy veiling grid flights, designed to lift the material up, then evenly spread it through the burner’s heat stream.

The SJ2 flight system consists of three flights, each varying slightly in their individual design and serving a separate function within the veiling process. These three flights are installed in a specific order to facilitate the optimum veil. The order is then staggered from row to row within the SJ2 section of the CFM series dryer, ensuring that the Hauck Starjet long-nosed burner encounters all stages of a robust veil at any given moment.

 

CFM Series Counterflow Dryer / Drum MixerCombustion Zone

The material then continues to travel down the drum towards the burner flame where it encounters the next set of flights known as combustion flights. It is here where the combustion flights lining this section of the counterflow drum perform two crucial functions.

First, they prevent improper combustion of the burner flame by lifting and moving the aggregate in a way that prevents the material from falling through the flame.  The secondary function of the combustion flights is to act as a type of heat shield, preventing this section of the drum shell from overheating due to it’s relatively close proximity to the burner flame.

 

Counterflow Dryer / Drum Mixer 1Mixing Zone

Lastly, the virgin material travels behind the burner flame into the mixing zone where liquid asphalt, RAP (recycled asphalt pavement), fines, and additives are blended into the mix via mixing flights. It is in this mixing chamber that the benefits of counterflow technology are truly realized. Conducting the mix process away from the hot gases and burner flame allows the CFM series counterflow drum mixer to eliminate the environmentally harmful hydrocarbon (blue smoke) emissions seen in more traditional plant technology.

Additionally, this counterflow system allows for a significantly higher amount of RAP to be utilized, drastically reducing overall operating costs. With five separate models of CFM series counterflow drum mixers available, Aesco Madsen is able to offer this versatile system to meet any need, matching the specific production requirements of each and every customer.

Superior Veil Technology Through Custom Flights & Direct Drives

As mentioned previously, it is extremely important to have the right veil of material within the drum. A veil that is too thick will impede the heat flowing into the baghouse, causing moisture within the baghouse to condense. This unwanted moisture will result in dust caking to the bags, lowering baghouse efficiency and overall plant production.

Alternatively, too thin of a veil will result in an excess of heat entering the baghouse creating a fire risk. The operator is then forced to trim down the burner, which also lowers overall plant production. Once one understands that the veil influences almost every aspect of an asphalt plant, it can be easy to see why a well-distributed veil is extremely important. It is for this reason that Aesco Madsen has focused so much effort on, and succeeded in, producing the perfect veil.

Two crucially notable components that work in unison with one another in order to create the perfect veil found in Aesco Madsen’s CFM Series counterflow drum mixers are: Custom SJ2 Veiling Flights, and Variable Frequency Direct Drives used to control the drums rotational speed.

SJ2 Flights

Aesco Madsen’s custom SJ2 Bolt-in-Flights were developed by industry experts within the company based off of decades of experience and careful research into the physics behind producing the perfect veil. Exclusive to Aesco Madsen drum mixers and available in a variety of angles for an added dimension of adaptability; the SJ2 Bolt-in-Flights have been central to the success and reputation that the CFM series counterflow drum mixers have received over the years.Counterflow Dryer / Drum Mixer 2

Variable Frequency Direct Drives

Variable frequency direct drives are the second major component responsible for the sought after veil seen in CFM Series drum mixers. This innovative feature provides complete control over the drum mixers rotational speed through the simple turn of a dial, allowing the drum to be fine-tuned in order to pinpoint the speed where the SJ2 grid flights within the drum produce the perfect veil for any given production requirements. Additionally, the direct drive design eliminates the efficiency losses found in traditional pulley motor systems. As the name suggests, the direct drive motors eliminate the need for the pulleys traditionally used to rotate the trunnions. The result is an increase in plant efficiency and a reduction in obsolete components that are likely to wear down and need replacement.

Available in a wide range of models to meet the specific output requirements of each and every client, the CFM series comes equipped with a full suite of industry leading standard features. A broad selection of additional upgrades are also available for customers who would like to explore the upper limits of plant efficiency and performance. For additional information on how the CFM series counterflow dryer / drum mixer can improve your plant operations, contact one of Aesco Madsen’s knowledgeable sales representatives today.

Satisfied Customers

"We are consistently running 45% R.A.P. with Aesco Madsen’s drum and haven’t had any issues. Flighting and airflow are great and the R.A.P. collar is easy to clean out. On top of that, their customer service is excellent."

Doug Elliot

Central Paving, Boise, ID