Furnace Muffle Failures: 3 Warning Signs

As a maintenance manager, you’re likely keeping a careful eye on your furnace muffle and the products your furnace produces. You’re also hoping that your muffle provides optimal performance and a long lifespan. But muffles will eventually need to be replaced, and there are some early warning signs you should look for.

These early warning signs are important for several reasons. First, you’ll get an indication of when you’ll need to stop production for a muffle replacement. Second, you can begin discussions on how you’ll address these failures.

Here are three things you should look for:

Dew Point Readings

Dew point issues are indicative of a muffle failure. Remember that moisture is incredibly detrimental to a furnace. Your dew point readings indicate a hole or a breach somewhere within the muffle. This breach is a prime spot for atmosphere to concentrate, which could translate into lost product if not addressed.

Humping or Collapsing

If the roof of your muffle is collapsing, or the bottom is starting to hump, it could be a sign of early failure. You should also keep an eye out for wear patterns on the belt. If the sides of the belt are gnarled or shredded, that could be due to humping or side wall distortion.

Discoloration

As you look down the length of a muffle, it should be glowing red. If you see discoloring or dark spots, that could be indicative of failure. It’s possible that the muffle isn’t holding temperature due to a cold point, or that the material at that specific location exceeds optimal operating temperature.

How to Address Muffle Failures

First and foremost, you need to understand your reasons for failure and initiate discussions on how they can be addressed with trusted industry professionals.

You might consider testing a new design that incorporates a different alloy to better resist creep at higher temperatures. Or you might opt for a muffle strengthened to prevent the bottom from humping. Every furnace is different, and your goals are unique to your manufacturing operations but there are ways to address the above issues based on what you hope to accomplish.

We have an entire article on why proper muffle design is important; it provides additional details on materials selection, welding capabilities and proper corrugation, all of which can help address failure points.

Finally, we always recommend working through design modifications as early as possible. This involves conversations about goals, design, performance, lifespan, and more.

Few things are more frustrating than unexpectedly pulling a muffle out of service. But if you keep an eye out for these warning signs and take steps to address them, you’ll be in a good position when it comes time to replace it.

Alloy Engineering offers muffles in a variety of application-specific configurations. To learn more, contact us here or call us at 440.243.6800.