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Envelope / Shuttle / Tunnel Kilns + Furnaces

The difference between an envelope kiln and a shuttle kiln is moving the kiln or furnace over a stationary ware platform or moving a loaded ware platform (called shuttle or bogie) into a stationary kiln or furnace. The stationary platform of the envelope kiln can be densely set with ware without fear of the load tipping over when the kiln is moved. One platform can be loaded/unloaded while the other is being fired.

Envelope furnaces/kilns require about 1/3 less floor space than comparably sized shuttle kilns. Both type of construction can be built to achieve the similar process parameters. Choosing one construction type over another is dependent on different factors. Loading delicate parts onto stationary ware platform(s) and moving the furnace over the ware platform for the heat processing cycle can be mandatory to achieve high yields. This type of construction is favored for ceramic application. If the part permits to be moved (on a shuttle or bogie), the shuttle design may have an economic advantage due to reduced duct work and more options with floor layout. The biggest advantage of this furnace design is the temperature uniformity which is achieved by having heated surfaces on five sides.

General Capabilities

  • Designs from 36 to 800 ft3 of working volume
  • Electric heating for kilns from 36 to 300 ft3
  • Gas heating for kilns from 48 to 800 ft3
  • Standard gas kiln setting widths of 4, 5 and 6 feet
  • Single or multiple zones of control
  • Manual or fully automatic firing control
  • UL approved control panels
  • FM, IRI and NFPA 86 compliant combustion safety equipment

General Applications:

  • Ceramic membranes in solid oxide fuel cells
  • Art ware
  • Dinner ware
  • Garden pottery
  • Lamp ware
  • Tile
  • Refractories

For use to 2420°F (1326°C) or cone 12 with gas or electric heating, envelope kilns are especially well suited for firing and decorating earthenware, stoneware and porcelain products. Higher temperature models are also available for specialty products.

Precision Heating Systems
Keith gas-fired kilns use atmospheric inspirator or sealed package burners. These burner systems feature multi-zone control and pulse firing for more uniform firing temperatures. All our gas systems have combustion safeguards.
Electrically-heated kilns have heavy gauge wire heating elements supported on ceramic rods, or rod-over-bend elements mounted along the sidewalls. This clean-firing, durable construction provides very uniform temperatures.

Automated Kiln Control
All Keith kilns feature digital process controls. Everything from programmable heating and cooling to pulse firing and gas safety logic is managed automatically using the latest control technology. Digital communications with a remote supervisory workstation is a popular option for larger kilns.

Contact Keith Company to order an envelope or shuttle kiln for your application, or to learn more about any of our products.