Elevator Furnaces

Elevator Kilns and CalcinersHarper’s multi-stack periodic high temperature elevator kilns offer precise, automatic control of temperature and oxygen content in the heating chamber. Our unique system, custom designed to client specifications, accommodates reactive or inert gas atmospheres as well as other specialty atmospheres.

Elevator furnaces are ideal for reduction, calcination, sintering, application of coatings, and other processes. The Harper system provides superior temperature uniformity, boasts energy efficient insulation, and delivers an ultra-pure atmosphere to process critical materials with minimal gas consumption.

Box Furnaces

Box kilns are an effective choice for reliable, repeatable thermal processing for ceramics, metals and carbon materials. We apply the same expertise as in our more complex high temperature furnace designs with advanced features that provide faster heating and cooling, excellent temperature uniformity, and reduced energy consumption. A complete system can be configured with atmosphere flow control, gas tight construction, zoned temperature control, and process instrumentation for fully automated processing. Harper’s team can help design box furnaces ideal for research and development purposes as well as batch production.

Retort Furnaces

Advanced coatings applicationsHarper’s specialized heat processing system for the application of heat resistant coatings offers many advantages over a vacuum furnace systems, including high quality and reliability, improved process flow, reduced maintenance cost, and productivity enhancement. This kiln incorporates significant design enhancements such as variable mass flow controlled gas flow into the retort, oxygen and water vapor sensing systems, additional heating elements and control zones for exacting temperature uniformity (± 5°C), and isolated cooling chambers.

The Harper system includes two kiln cars with independent cooling chambers. The first car is moved automatically into the furnace, removed hot, and transferred into the cooling chamber. The second car is then loaded, increasing furnace utilization and greatly improving the process flow throughout the entire coating operation. Isolating the cooling process offers a dramatic improvement to the work environment and reduces the air conditioning load.

Hearth Load Carrier Furnaces

A major innovation in graphite systems technology, the heart of this patented new system is the Harper Hearth Load Carrier. It reduces load thermal mass, improves temperature uniformity and redistributes compressive stress and wear surfaces away from potentially corrosive/erosive environments. The Graphite Harper Hearth has energy recuperation and single point access that significantly improve process economics over existing ultra-high temperature pusher and other furnace technologies. Applications include gas-solid and solid-solid chemical reactions and pressure-less sintering at temperatures up to 3000ºC.

Tungsten Reduction Systems

This revolutionary system concept facilitates high production rate in a  single installation with the lowest cost of production and the greatest flexibility to alter material grain size and morphology. It features a pusher-style system with single muffle, externally heated by natural gas or electric with maximum temperature 1100°C. Production rates are up to 100 kg/hr  (at maximum bed depth and velocity).  The double door tray and product  entry and exit system reduces gas losses, and the design allows gas dew point control at multiple locations inside the high temperature section. It also offers a hydrogen recycling system rated for 650 m3/hr, -65°C dew point.

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