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Harper International Rotary Calciners

Harper rotary tube furnaces and rotary calciners are designed for continuous processing of granular, powder, or particulate aggregates under controlled atmosphere environments at temperatures
up to 2400^o C. 

Rotary furnace systems may be electrically heated or gas, oil, or dual fuel fired.  The tumbling action of the product within the rotary tube results in high degrees of temperature uniformity and gas-solid contact resulting in more homogenous product, reduced processing times and increased production rates.  No carrier media is required so energy is not expended in heating carrier loads.  Recuperation further enhances energy efficiency in fossil fuel fired rotary furnaces.  Harper rotary tube furnaces and rotary calciners offer exceptional versatility, reliability, and energy efficiency

• Temperatures to 2400^o C
• Electrically heated or gas fired
• Controlled atmospheres including flammables
• Defined residence times
• Control of exothermic reactions
• Off-gas handing systems
• Testing and prototyping facilities
• Process modeling and scale up
• Complete systems and turnkey installation

• Calcination
• Reduction
• Controlled oxidation
• Carburization
• Solid-solid reaction
• Purification
• Research and development
• Waste remediation

• Many patented features
• Energy saving design
• Multiple temperature control zones
• Exclusive rotary seal design
• Automatic lubrication
• Feed level detection
• Process gas circulating and conditioning systems

• Phosphors
• Titanates
• Zinc oxide
• Quartz
• Ferrites
• Molybdenum
• Cobalt
• Tungsten
• Tungsten carbide
• Catalysts
• Activated carbon
• Inorganic chemicals
• Metals and metal oxides
• Rare earths
• Uranium compounds

MAJOR ADVANCES in HARPER Rotary Tube Furnace Systems

High Temperature Graphite
Rotary Tube Furnace System

The Harper Graphite Rotary Tube furnace system is the most advanced available today.  It utilizes no moving parts in the tube support system providing a simple, reliable, robust design that enhances scalability.  Applications include carburizing hard metal powders, carbon and graphite powder processing and synthesis of non-oxide ceramic powders.

(above) PATENTED Multi-zone Graphite Rotary Tube Furnace

Riffle Flights

Riffle flights provide axial mixing for processing at a fixed average composition.
Excellent for moderating exothermic reactions or simply continuous in line mixing.

           
  (above )PATENTED Riffle flights schematic   

                   (above) Riffle flights installation.

Minimized Residence Time Distribution

Helical flights convey material without back – mixing.  Utilized for processes that require narrow residence time distributions.

Ideal Plug Flow             

Enhanced Heat Transfer

Tubes penetrate the material process bed. Mating refractory shapes channel heating or cooling gases in an overall countercurrent stream for high heat transfer.  Ideal  for temperature sensitive materials.

              EHTA System

Superior Gas-Solid Reaction

Coarse , free flowing material can be heated and reacted with through-flowing gas.  Gas flows locally normal to the solid material path while globally flowing counter-current to material flow providing superior gas – solid contact.

PATENTED Cross Flow System.                        

Advanced Sealing System

Patented rotary reactor sealing system provides optimal rotary tube furnace atmosphere integrity with minimal gas consumption.



(right) PATENT PENDING Sealing System

Feasibility, Process Analysis and Advanced Design Studies

Harper's Advanced Technology Center and interdisciplinary team of chemical and mechanical engineers and materials scientists are available to explore, develop and scale up exciting new rotary tube furnace processes and applications.

Our technology group possesses expertise in areas as diverse as carbon and graphite processing, inorganic chemicals, non-oxide ceramics, nano-composites and other advanced materials.  Advanced design and analysis incorporates solids flow, heat transfer and computational fluid flow modeling enabling concurrent engineering, reduced project lead time and process optimization.

Rotary tube furnace available for on site testing at the customer’s facility on a rental basis for extended campaigns.

Complete Systems

Turnkey Rotary tube reactor system with automated material feed and discharge, PLC based executive control instrumentation and complete off gas handling.

The design of  the rotary  tube system can also incorporate process controls, skid mounting,  turnkey installation and complete field commissioning. Field service can incorporate control instrumentation integration and programming as well as process engineering optimization and support.
 

Versatility and Customization

Cascade rotary tube furnace system capable of multi-stage thermal processing at different temperatures and atmospheres without exposure to ambient conditions or manual material handling
 

Rotary tube furnace featuring enhanced reliability and simplified mechanics for limited access sites such as hot cells.

Multiple zone gas fired rotary tube furnace providing enhanced temperature profile precision and flexibility.