Rotary Drum

Rotary Drum dryers are used particularly in the mineral industry. Their main features are high throughput rates and the ability to process solid materials with widely differing granulometric properties. Rotary drum dryers have the option of multiple shells to include cooling in the machines process and reduce space consumption.
Double Shell Rotary Dryer cooler
Single Shell Dryer

Single Shell Rotary Drum Dryer - Allgaier Dryer

Single-shell drum dryers are used for drying without subsequent cooling.
They are typically a “once through” process and are the simplest form of drying.Up to 4 meter [13.12336 ft] diameter
Up to 30 meter  [98.425197 ft] length

Double Shell Dryer

Double Shell Rotary Drum Dryer - Allgaier Dryer

In double-shell dryers, drying takes place in both shells in the counter-flow principle using the hot drying gas.
Their short length means that double-shell dryers are popular and frequently used.Counter flow principle
Space optimization

Triple Shell Dryer

Triple Shell Rotary Drum Dryer - Allgaier Dryer

Triple-shell dryers can be installed in the most compact space.
They are especially suitable for finely grained materials such as quartz sands.Suitable for fine particulate
Outer shell provides optional cooling
Up to 30 meter  [98.425197 ft] length

rotary drum options dryer cooler allgaier dryer cooler


Additionally, ALMO offers rotary kilns used for calcination and cooling of finely-grained solids.These can be Direct or Indirect rotary units. Indirect Rotary units are primarily for inert product, to prevent oxidization. While direct can be used for high temperature applications. The materials handled include Zeolites, Clay, Silicate Powder, Gypsum, and more.

Drum dryers with integrated cooling consist of two tubes [drums] pushed one inside another. While the drying is taking place in the inside tube, the dried and still warm product passes through the outer tube for cooling, and is cooled using cold ambient air in the counter-flow principle.

TK System is a double-shell drum with cooling path, for grain sizes up to 32mm [about 1 1/4 inches] (sand, crushed rock, clay, sludge…) Cooling with air.

“TK Plus” – particularly effective (Evaporative Cooling Effect)
In this system, a partial amount of moist material is added to the dried but as yet uncooled product, so the cooling effect is assisted by the evaporation of water from the moist proportion of the solid material.
The heat from the dried solid is used for drying the partial quantity of solid. The entire energy consumed for heating the dryer as well as the entire amount of air for drying and cooling are significantly reduced.
Static tublar coolers which are coolers with cold water are also available for indirect cooling of the product after drying.
Evaporative Cooling can save as much as 25% of the drying energy cost, depending on the initial moisture content and the particle size. Contact ALMO Process for in-depth discussions on how Evaporative Cooling can be utilized in your process.

Drum Dryer Advantages

•   Suitable both for coarse and fine solids
•   Largely insensitive even to very coarse or heavy solids
•   Minimal cost and effort for the supplied air equipment with direct installation of the burner at the dryer casing
•   Insensitive to changes in the particle size
•   Insensitive to variations in the moisture content and the throughput
•   Insensitive to cut-out of the drying air
•   Low specific electrical energy requirement
•   High drying air temperatures combined with low heat losses
•   Low heating energy requirement even when drying only partial loads by adjustment of the exhaust air volume
•   Simple installation and fast commissioning
•   Tolerance to operating faults
•   Very rugged and thick-walled equipment with a long life-time
•   Low wear and low replacement part requirement

Drum Dryer Disadvantages

•   A requirement of heavy equipment (thick-walled design of the drum)
•   Cooling in double-shell drying/cooling drums is limited to solid material temperatures of 55 °C to 60 °C [131-140°F]  at the dryer exit
•   Internal fitting design in drum dryers requires many years of experience
•   Solid materials are only partially de-dusted in drum dryer
•   Counter-flow applications are limited to coarse-grained materials

Rotary Dryer / Cooler

Range of material from fine to very coarse
Non-uniform particle distribution
Non-uniform solids quality
Possibility of very high drying air temperatures
Use of direct gas or oil burners
Cooling to 55…66°C [131-150.8°F] sufficient or no cooling necessary
Thick – Wall Model and special design of the internal fittings for abrasive materials
Changing throughput rates and fast load changes
Mild Steel application sufficient
No space for a complex supplied air system
Simple dryer solution for overseas and developing regions
Drying of limestone with simultaneous dry cleaning
Outdoor installation required

Fluid Bed Dryer / Cooler

Drying of fines 0…4mm [5 USmesh] with a max of 0…6mm [1/4USmesh]
Generally uniform particle distribution
Uniform solid qualities
Suitable for temperature sensitive materials
Surface heaters or steam heated exchangers in air supply system
Cooling to 40…45°C [104-113°F] required
Gentle treatment for particularly sensitive products from upstream granulation equipment
Uniform throughput rates close to design specification
Low-price stainless steel designs for the chemicals and foodstuffs industry
Constant production conditions in well-developed infrastructures
Defined de-dusting (filter reduction) required
Indoor or covered installation recommended

Rotary Dryer Questionnaire
Questions marked by * are required.
1. Name: *
2. Email: *
3. Company Name: *
4. Address, City, State, Zip/Postal Code: *
5. Phone: *
6. Tons/Hr Feed Rate (wet):
7. % Moisture/wt in Feed:
8. % Moisture Discharge Wanted:
9. Cool Product to __ Degrees F (leave blank if no cooling):
10. Type of Rotary Dryer:

  • Single Shell Dryer
  • Double Shell Dryer
  • Triple Shell Dryer
  • Dryer & Cooler
  • Dryer & De-Dusting
  • Dryer & Separation
  • Drying & Shredding
11. Type of Fuel You have Available (check all that apply):

  • Natural Gas
  • Propane
  • #2 Fuel Oil
  • Heavy Oil
  • Waste Oil
  • Waste Heat
12. Elevation at Sea Level:
13. Type of Quote Wanted:

  • Full
  • Budget
  • Call Me
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