Modified Catenary Furnace Muffle Cross-Section vs. Traditional “D” Shape

The use of the modified catenary arch in the cross-section shape of the top of a muffle chamber is a design concept departure from the traditional “D” shaped cross-section. The catenary arch with modified sidewall presents a new optimum section. This arch allows maximum support of the roof at elevated temperatures where the creep strength of the material is low. As the shape of the catenary arch gives support to the roof, the slight angular design of the sidewall changes the moment of directional force. This improves the muffle’s resistance to sidewall deformation.

Alloy Engineering combines the modified catenary design with a deep corrugation in the roof section. This combination provides the best possible strength given the allowable furnace change dimensions and the necessary clearance inside the muffle for the desired work load package. Our use of the corrugated modified catenary design gives the muffle design:

• Greater resistance to roof collapse
• Longer resistance to sidewall bulging
• Maximum work load package size within a higher strength matrix
• Significantly longer working life at temperature