Cold Face Repair & Ceramic Media Replacement

December 20, 2021


A rotogravure printer needed additional capacity for a plant expansion. Their existing 60,000 scfm RTO did not have enough capacity for the new press. A mothballed 40,000 scfm RTO on site could provide a solution if it could be brought back to life, including new ceramic media and a repair of the cold face, at a reasonable cost.


collapsed bed of structured ceramic media inside an RTO
Collapsed Bed of Structured (MLM) Ceramic Media

Damaged Cold Face

regenerative thermal oxidizer combustion chamber interior with broken cold face seam and leakage
Broken cold face seam/leakage + temporary fix at broken seams
RTO cold face with broken seams
Broken Seams (2 per bed)


An inspection by Kono Kogs determined that the cold face was well built, but had a weak link in the light gauge expanded metal chosen for the cold face material. The light duty cold face sagged under the weight of the ceramic media and broke the welds of the seams (2) in each bed.

This lead to some media loss through the broken seams, but most loss occurred on the ends of the bed where the cold face had pulled out from under a designed lip. The lip did not account for the sagging and resulting pull of the cold face from under the lip. Ceramic media broke down in the corner where the cold face opened up.

This had a cascading effect that eventually collapsed the media along the whole end of both beds. Kono Kogs fabricated a cold face repair that utilized the existing support channels, but utilized a heavier gauge expanded metal with larger sheets resulting in 50% less overall seam length. The heavier gauge expanded metal allowed deeper weld penetration and therefore greater strength.

Scroll down to see the repair & replacement in a series of photos:

40,000 SCFM Regenerative Thermal Oxidizer (RTO)

preparing to open a regenerative thermal oxidizer for cold face access

Removing Top for Media Replacement Access

crane removing the top of an RTO to access the ceramic media beds

Partially Loaded Media Bed

partially loaded media bed inside an RTO

Fully Loaded Ceramic Media Beds

partially loaded media bed inside an RTO

Fully Loaded Ceramic Media Beds w/Combustion Chamber in Place

fully loaded ceramic media bed with combustion chamber cold face support repaired


The cold face repair was made over a three-day period and included other weld repairs and cold spot repairs to the insulation. Since the RTO had been off-line and the press was not yet in place, the turnaround time was not critical.

For a closer look at RTO combustion chambers and cold face support, see the first three videos on our FAQ page.

Highlight of this project:

“Kono Kogs crews were professional and hard workers with a good attitude. Our project went as planned with very good communication and coordination”

Equipment / Services provided by Kono Kogs, Inc.

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About Kono Kogs

Kono Kogs has been refurbishing used thermal oxidizers for over 25 years with over 400 installations in nearly every state in the USA and many other countries/continents . We offer full refurbishing of quality-built thermal oxidizers and stand behind them with warranties that match new equipment OEM warranties.