WHRU Dampers For Heat Recovery

DTL manufacture specially engineered louvre damper systems for waste heat recovery unit (WHRU Dampers) applications including HRSG and OTSG where the control of turbine exhaust gas is critical.

DTL WHRU dampers are designed for turbine exhaust operating conditions (typically 550-600 Deg C) with parallel blade action or opposed action depending on the customer’s control needs.

In addition, fail safe actuation systems ensure smooth operation to control the exhaust flow to the waste heat recovery bundle between 0% to 100% whilst ensuring that the damper moves to the bypass position in the event of a system trip or emergency shut down. Actuators can be pneumatic, electric, or hydraulic. Finally, an optional manual override can be provided with all systems.

Then, the inlet and bypass blades are normally mechanically linked to prevent simultaneous closure of WHRU damper and BYPASS damper.

WHRU Damper Sealing

In general our WHRU damper blades are fitted with flexible inconel seal elements (sometime called lamella) which seal against solid landing bars inside the perimeter of the duct. Furthermore a sealing air system can be fitted as an option to provide 100% exhaust gas isolation to the heat exchanger.

DTL provide both hot casing (external insulation) and cold casing (internal insulation) options to match the customers exhaust system and WHRU design.

Dampers used for waste heat recovery on WHRU and OTSG Once through steam generators

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Typical WHRU Damper Applications

  • Exhaust systems
  • Gas Turbine
  • HRSG
  • Waste Heat Recovery
  • Bypass Systems
  • OTSG

WHRU Dampers Specifications

Technical Specifications

  • Pressure: Typically 6Kpa (600mmWG) however we can design for higher on request
  • Temperature: Typically 600°C (1112°F) however we can design for higher on request


  • Circular or rectangular louver damper designs
  • Fully welded body
  • Specially engineered compact design
  • On/off or modulating
  • Sized to suit exhaust gas flow
  • Pneumatically actuated (Electric or hydraulic actuators also available on request)
  • Mechanically linked inlet & bypass

Optional Extras

  • Double linkage design
  • Failsafe control system
  • Maintenance free bearings
  • End connections: Flanged to fit ANSI, EN, JIS standards
  • Flexible metallic seals to increase sealing efficiency
  • Seal air for 100% sealing
  • Stainless steel and offshore design spec
  • API 560 Compliance

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