Louver Dampers

Model LSI (Square or Rectangular) and Model LRI (Round)


Heavy duty industrial grade louver dampers are available with parallel or opposed action linkage for isolation and/or control of process air and gas.

Standard and optional features are available to meet the needs of your specific application. We specialize in custom designs for unusual or severe duty applications.

Application / Design Data:
Our standard construction is suitable for internal temperature of 800° F. If bearing temperature will exceed 200° F (dependent upon ambient temperature, insulated duct. etc.) then the optional high temperature carbon sleeve bearings are required.

Optional construction features for operating temperature to 1600° F.


FRAME: Carbon steel formed channel (LSI). Our standard bolt pattern. FTF dimensions selected to keep the vanes within the damper frame in the full open position. FRAME: Structural channel, angle or special dimensions formed channel in any weldable material. We can provide any dimensions for your special retrofit application.
VANES: Carbon steel, double thick air-foil vanes, welded to through shaft. (LSI) single thick plate (LRI) VANES: Stainless, corrosion and abrasion resistant materials.
SHAFTS: C-1018 CRS continuous through shaft. Shaft ends are marked to indicate vane position. BEARINGS: High temperature carbon sleeve bearings. (Stainless steel shafts are recommended when using these bearings.)
BEARINGS: Ball bearings mounted outboard on stand-offs, over adjustable packing glands. SHAFTS: Stainless steel continuous.
GLANDS: Adjustable plate & follower design with fiberglass rope packing. GLANDS: Ceramic rope packing or any other commercially available packing material.
LINKAGE: Heavy duty, non-adjustable, bar linkage mounted outboard with a bronze bushing and shoulder bolt connection at each pivot point. Parallel or opposed action. LINKAGE: Adjustable linkage with threaded rod and pipe linkage bars and rod end bearings.
SEALS: No internal vane seals provided. Swing clearance between vanes and frame for approximately 90% shut-off. SEALS: Optional seals for up to 99% shut-off available.
PAINT: Damper is hand cleaned and painted one shop coat of our standard industrial primer. PAINT: Special surface preparation and coatings are available.
OPERATOR: None. Extended operator shaft is provided for customer use. OPERATOR: Wide range of manual, electric, pneumatic and hydraulic operators with options for modulating, fail safe, switches, etc.

  • Mounting of customer supplied operator and accessories.
  • Inlet screens, mating flanges, special duct sections. (tees, transitions, weather hoods, etc.)
  • Castable refractory linings, heat shields, position indicating switches, slave linkages.