Danser recently fabricated and installed a refractory-lined furnace exhaust system for a large production pre-heat furnace. Fabrication included a 65″Ø 12 gauge aluminized stack, 46′ high with 304 stainless steel rain cap and support steel. Ductwork was 65″Ø and 49″Ø 12 gauge aluminized steel with painted stands from carbon steel tubing and plate.

The refractory lining was made from Vacuduct®​, Danser’s high-temperature ceramic fiber insulation, 2.5” thick, 2600° F fiber. The Vacuduct was “wetlined” to ensure secure and seamless insulation in the high-temperature system. The Vacuduct lining was much lighter than a castable alternative and allowed the system to be fabricated without expansion joints, a significant cost savings to the customer.

The job was over 1100 man hours completed with 0 injuries.

“We custom designed the exhaust system to the customer’s furnace,” said Scott Miller, Danser Field Superintendent. “We took measurements and built the Vacuduct-lined ductwork and connections to fit their existing layout. The time spent in the shop on a custom system saves significant time in the field, allowing our crews to finish well within customers’ shutdown schedules.”

Following installation, the exhaust ducts reached only 120° F on the cold face while the furnace was operating at over 2300° F. That’s insulation doing its job.

Installing 12ga aluminized steel 65″Ø exhaust stack lined with Danser’s high-temperature ceramic fiber insulation.

Installing 12ga aluminized steel 65″Ø exhaust stack lined with Danser’s high-temperature ceramic fiber insulation.

Installing 304SS rain cap.

Completed insulated exhaust stack.

Exhaust duct connection from the exterior to interior of the plant near the furnace. System utilizing 65″Ø and 49” Ø 12 gauge aluminized steel duct.

Insulated exhaust ductwork custom designed for customer’s furnace.

Completed high-temperature furnace exhaust ductwork.

Furnace operating at over 2300° F, with the cold face of the exhaust ducts reaching only 120° F.