Furnaces, Kilns, Ovens, Lehrs
and Thermal Oxidizers
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Envelope kilns for solid oxide fuel cells (SOFC) & CMC's

  • Envelope Kiln with thermal oxidizer
  • Envelope Kiln for advanced materials
  • Envelope Kiln with Riser Door
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What is an Envelope Kiln?
The key design feature of envelope kilns is that they roll on wheels over one of several supplied stationary ware platforms.

You can fire decoration in 1400°F, as well as bisque or glost fire ceramics to 2300°F, in Keith’s fiber-lined, gas fired envelope kiln in volumes from 60 ft3 to 1000 ft3. Binder burnout with a thermal oxidizer and sintering process for processing of green ceramic membranes such as ceramic oxide fuel cells (SOFC) and ceramic matrix components (CMC) in one system.

Keith’s envelope kilns have the advantage of rolling over one ware setting or another, without ever having to move the stationary ware setting. This envelope kiln is especially well-suited for firing tall or fragile products like ceramic wafers. And, the envelope kiln uses a 1/3 less floor space than a comparably-sized shuttle kiln.

This kiln is extremely energy efficient because it is fiber-lined. Programmable temperature controls automatically fire the kiln through the complete firing cycle. Keith’s user-friendly control system can be fully depended upon to fire the kiln with ease and excellent repeatability cycle after cycle.

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.