7" Smoke Chimney Cap

Lukjan Non-Adjustable Rain Cap — Series 47, 7″ Ø, 9-1/4″ Length × 11-1/2″ Width

Fixed (non-adjustable) rain / vent cap designed to cover and protect the open end of a 7-inch round duct or flue from rain, snow, debris, and pests. The Series 47 type uses a hooded top and side walls (brim) to direct water away while allowing air / exhaust flow. The specified footprint (9-1/4″ depth, 11-1/2″ brim width) provides a generous overhang to shield the duct opening.

• Series / model: Series 47 non-adjustable rain / chimney cap (Lukjan) — the 7" version marketed as “7″ Smoke Chimney Cap” by US Supply. :contentReference[oaicite:0]{index=0}
• Part / MPN: RX2807 (7″ Smoke Chimney Cap) :contentReference[oaicite:1]{index=1}
• Nominal duct connection: 7 inches diameter (round duct / chimney) :contentReference[oaicite:2]{index=2}
• Overall depth / projection (front-to-back): 9-1/4 inches (9.25″) :contentReference[oaicite:3]{index=3}
• Overall brim width (across hood): 11-1/2 inches (11.5″) :contentReference[oaicite:4]{index=4}
• Material: Galvanized steel (standard for Lukjan metal duct / vent caps) :contentReference[oaicite:5]{index=5}
• Finish: Galvanized (zinc coating) to resist corrosion in outdoor exposure :contentReference[oaicite:6]{index=6}
• Weight: ~0.50 lb (as listed for the 7″ cap) :contentReference[oaicite:7]{index=7}
• Design / features:
  • Non-adjustable, fixed hood design (no movable parts or adjustable height)
  • Wide hood overhang / brim helps deflect rain downward and away from the duct inlet
  • Side walls (vertical skirt) protect against wind-driven rain or snow from entering the duct opening
  • Hemmed or flanged edge details likely used on cap brim edges to stiffen sheet metal and avoid sharpness (typical in duct caps) (inferred)
• Installation / mounting:
  • Slip or fasten the cap over the duct / chimney pipe end (the round duct must extend above the roof / termination point to accept the cap)
  • Secure with sheet-metal screws or fasteners (stainless or corrosion‐resistant) through skirt / flanges into duct wall
  • Seal the base between the duct and cap with appropriate sealant or flashing to prevent water ingress at the joint
  • Ensure stable and level mounting to avoid cap movement or stress under wind loading
• Performance & design considerations:
  • The generous brim width (11.5″) relative to the 7″ duct provides a good protective “umbrella” area to block rainfall entry even under moderate wind angles.
  • The depth (9.25″) ensures vertical clearance so water drips clear of the duct opening rather than splashing inward.
  • Galvanized steel construction is suitable for typical outdoor exposure; however, in highly corrosive or coastal environments, optional stainless steel or coated versions may be recommended.
  • The fixed design has no moving parts, which improves longevity and reduces maintenance complexity compared to adjustable caps.
• Limitations & notes:
  • Because it is non-adjustable, the cap may not provide optimal sealing if the duct length varies; alignment must be precise.
  • Large overhang may catch debris (leaves, twigs) — periodic inspection / cleaning is recommended.
  • The cap should maintain clearance to surrounding structure (eaves, walls) to prevent interference or moisture accumulation behind the hood.