Flange Heat Dissipation Fins and Thermal Shield (FK)
An engineered thermal management architecture combining natural convection copper cooling fins and composite thermal break barriers, intercepting conductive thermal bridges transferring heat from hot duct flanges to the outer fabric belt.
Hot process flue gas (500°C to 850°C) conducts heat directly through the metal duct flange to the clamping bars securing the fabric expansion joint.
While the joint body incorporates thick insulating bolsters, the clamping zone requires the fabric to be compressed between steel bars for gas-tight sealing. Uninsulated, metal clamping temperatures can exceed 450°C, baking and embrittling outer elastomeric layers. BundleTec Flange Heat Dissipation Fins (FK) utilize high-conductivity copper fins to shed heat to ambient air, lowering clamping temperatures by 100°C to 180°C.
Thermal Duct Expansion & Sizing Engine
Interactively calculate axial and lateral thermal expansion, temperature gradients, and cold setting offsets.
Overview
Flange Heat Dissipation Fins & Thermal Shields (FK) protect fabric expansion joint attachment zones from extreme conductive heat transfer. Utilizing high-purity electrolytic copper fins or refractory mica composite thermal break gaskets, the system dissipates heat by natural convection, keeping outer elastomeric and PTFE membranes well below their degradation thresholds.
Applications
- Gas Turbine Exhaust Ducts & Silencer Transition Flanges
- Heat Recovery Steam Generator (HRSG) High-Temp Inlets
- Cement Rotary Kiln Tertiary Air Duct Connections
- Steel Mill Blast Furnace & BOF Gas Flange Joints
- Petrochemical Cracking Furnace High-Temp Ductwork
Technical Advantages
- Lowers clamping zone temperatures by 100°C to 180°C permanently
- Prevents charring, embrittlement, and bolt-hole tears in outer fabric layers
- Pure passive natural convection with zero electrical or maintenance costs
- Eliminates thermal bolt elongation, relaxation, and hazardous gas leaks
- Full compliance with DIN EN ISO 10211 and FSA-DSJ-402 standards
FK Technical Parameters & Operational Limits
| Fin Array Material | Electrolytic Tough Pitch Copper (k ≈ 385 W/m·K) or Thermal Aluminum |
| Thermal Break Gasket | Graphite / Mica Reinforced Composite (k < 0.15 W/m·K) |
| Operating Process Temp | Suitable for 400°C to 850°C Duct Gases |
| Temperature Drop (ΔT) | ΔT = 100°C to 180°C Net Cooling |
| Design Standard | DIN EN ISO 10211 · FSA-DSJ-402 |
| Attachment Mechanism | Welded Flange Backing Fins or Modular Bolt-On Collars |
Flange Heat Dissipation Fins and Thermal Shield (FK) — Detailed Architectural Design
1. Conductive Thermal Bridging Risks in Flange Connections
Flue gas heat transfers via conduction into the duct flange and clamping bars. Unlike the joint body where thick insulating bolsters isolate the fabric, the clamping zone must compress the fabric between steel bars to achieve gas tightness. Clamping temperatures above 150°C quickly degrade outer elastomers, causing cracking, embrittlement, and belt failure around bolt holes.
2. High-Conductivity Copper Fins & Natural Convection
BundleTec FK fins leverage copper's 8x higher thermal conductivity compared to steel (k ≈ 385 W/m·K vs. 50 W/m·K) to draw heat out of the flange metal and radiate it into the ambient air. The fin profile generates a natural chimney effect, reducing clamping root temperatures by 120°C to 180°C.
3. Composite Thermal Break Barriers & Insulating Gaskets
Where geometric constraints prevent fin arrays, low-conductivity refractory mica composite gaskets (k < 0.15 W/m·K) are placed between the duct flange and clamping bar. This breaks the metal-to-metal conductive bridge and keeps fabric temperatures within safe operating thresholds.
4. Plant Thermography Audits & Maintenance Rules
Infrared thermography audits demonstrate that unprotected flanges reached 380°C with severe fabric charring, whereas identical flanges equipped with FK fins stabilized at 190°C with 100% fabric integrity. Fin surfaces must never be painted or insulated to maintain unrestricted convective heat exchange.
Calculate duct thermal growth and configure the right component →
Input duct cross-section and process temperatures to immediately determine axial and lateral displacement.
Compliant International Quality & Manufacturing Standards
All internal expansion joint components are engineered and fabricated to FSA and RAL-GZ 719 guidelines.
Gütegemeinschaft Weichstoff-Kompensatoren temperature categories 1-5, helium tightness and tensile strength standards.
Fluid Sealing Association FSA-DSJ-401/402 carcass internal hardware, flow liners, and clamping torque allowances.
Directives for static dissipation, equipotential bonding bridges, and explosion protection in Zone 1/21 environments.
Frequently Asked Questions
Why do expansion joint flanges overheat if the joint body is insulated? +
Because to achieve gas tightness, the fabric must be compressed between metal clamping bars and the duct flange without internal insulation. High process heat conducts directly through the steel, scorching outer fabric coatings.
How much temperature reduction do FK dissipation fins provide? +
Through passive natural convection and thermal break gaskets, FK systems typically reduce clamping zone metal temperatures by 100°C to 180°C.
How are the copper cooling fins attached? +
They are precision-welded or mechanically bolted to the exterior backface of the duct flange in an orientation optimized for natural ambient airflow.
What failures occur when flange heat is left unmitigated? +
Outer elastomer covers char and crack, reinforcement fibers shear under clamping pressure, and bolts relax from thermal elongation, releasing toxic or hot flue gas to the atmosphere.