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Why Use INEX U-Tube Systems?

  • Higher Heat Flux - Metal-alloy tubes are typically designed to radiate at 55 BTU/hr/in2 (25 KW/m2), but INEX tubes excel at much higher temperatures to 2450°F (1340°C) providing twice the heat flux output of 110 BTU/hr/in2 (50 KW/m2). Because INEX tubes can be fired so much hotter, they provide faster furnace ramp-up & recovery, reduced cycle time and tighter temperature control. With this in mind, consider a smaller INEX composite tube to replace a larger metal-alloy tube for both increased performance and purchase savings.
  • Longer Tube Life - Conventional metal-alloy tubes frequently fail due to creep, carburization, thermal shock, melt-through and oxidation. INEX composite radiant tubes eliminate these problems and out-live all other types. Lower your operating expense by reducing furnace downtime, tube replacement, and labor. 
  • Decreased Cycle Time - Higher radiant output means faster recovery to operating temperature than conventional metal-alloy tubes, insuring maximum furnace throughput and productivity.

U-Tube Brochure

General INEX U-Tube Installation Drawings


U-Tube 4.5 Inch OD Horizontal

U-Tube 6 Inch OD Horizontal


U-Tube 4.5 Inch OD Vertical

U-Tube 6 Inch OD Vertical

  • Gaskets & Rope Packing Kits
  • Mounting Hardware (Packing Gland System)

Wednesday, May 01, 2013(3 items)

Standard U-Tube Sizes

Tube Outside Diameter Tube Inside Diameter Centerline
4-1/2" (114 mm) 4-1/16" (104 mm) 9" (229 mm)
6" (152 mm) 5-1/2 " (141 mm) 9" (229 mm)
6" (152 mm) 5-1/2 " (141 mm)
12" (305 mm)


  • Atmospheric Annealing 
  • Carburizing 
  • Carbide Solution  Treating 
  • Neutral Hardening 
  • Carbo-Nitriding 
  • Stainless Steels


  • Endothermic, Lean & Rich
  • Carbon-Enriched Gases 
  • Ammonia-Enriched Gases 
  • Mixed 50/50 Endo-Ammonia
  • Exothermic
  • Nitrogen