Overview

The Ningbo Dimon Concealed Automatic Drop-Down Door Bottom Seal is a high-performance acoustic and environmental door sweep engineered for commercial facilities, hotels, recording studios, healthcare environments, and modern residential doors. Precision-extruded from architectural 6063-T5 aluminum alloy housing a self-leveling silicone rubber sealing gasket, it features an adjustable solid brass actuating plunger that automatically drops the seal flush against the floor when the door closes and instantly retracts upon opening. This design provides maximum acoustic isolation, thermal insulation, and dust/smoke protection while preventing any floor dragging, friction, or carpet wear. Available in standard U-channel and flanged bottom profiles across lengths from 600 mm (24") to 1200 mm (48"), fully trimmable on-site.

Key Features

• Automatic Mechanical Retraction: Solid brass plunger actuator depresses against the jamb when the door closes, dropping the silicone gasket to seal threshold gaps up to 15 mm. Retracts smoothly into the housing when the door swings open to eliminate floor drag and carpet abrasion.
• Superior Acoustic & Environmental Sealing: Dense, aging-resistant silicone rubber seal creates a tight barrier against airborne sound, drafts, outdoor dust, insects, smoke, and light infiltration.
• Architectural 6063 Aluminum Profile: Heavy-duty extruded aluminum channel resists corrosion, warping, and bending under high-traffic commercial use.
• Concealed Mortise Installation: Mortised directly into the bottom of wooden, composite, or hollow metal doors (15 x 30 mm or 15 x 34 mm slot) for an invisible, flush appearance that preserves clean architectural aesthetics.
• Dual Profile Styles:
  • Standard U-Shape Channel (Model m012b): Sleek rectangular profile for clean bottom mortising.
  • Flanged Winged Channel (Model m022): Integrated side flanges for convenient underside screw fastening.
• Field Trimmable & Adjustable: Sized in 600mm, 800mm, 915mm (standard 36" door), 1000mm, and 1200mm lengths; each unit allows up to 100 mm – 200 mm of field trimming at the non-plunger end for exact door leaf fit.
• Complete Contractor Hardware Kit: Includes brass plunger strike plate, stainless steel end caps, and mounting screws for fast, reliable installation.

Technical Specifications

• Product Type: Concealed Mortise Automatic Door Bottom (ADB)
• Housing Material: Architectural 6063 Extruded Aluminum Alloy
• Gasket Material: High-Elasticity Anti-Aging Silicone Rubber Seal
• Actuator: Solid Brass Adjustable Threaded Plunger Pin
• Standard Lengths:
  • 600 mm (approx. 24") — Trimmable
  • 800 mm (approx. 31.5") — Trimmable to 700 mm
  • 915 mm (approx. 36" North American Standard) — Trimmable to 800 mm
  • 1000 mm (approx. 39.4") — Trimmable to 900 mm
  • 1200 mm (approx. 48") — Trimmable to 1000 mm
• Profile Options:
  • U-Shape Mortise (14 x 30 mm body / 15 x 30 mm door slot)
  • Flanged Mortise (14 x 34 mm body / 15 x 34 mm door slot)
• Maximum Drop / Clearance Gap: Up to 15 mm (approx. 0.6")
• Suitable Doors: Solid wood doors, hotel guest room doors, commercial acoustic doors, composite doors
• Hardware Included: Strike plate, side cover plates, and stainless steel wood screws

Wholesale & OEM Capabilities

• Custom Lengths & Mortise Sizes: Custom manufacturing to project door schedules up to 1500 mm (60").
• Surface Finishes & Anodizing: Standard mill/satin silver, matte black anodized, champagne, or bronze.
• Fire & Acoustic Rated Formulations: Flame-retardant silicone rubber and UL 10C / BS 476 compliant test-ready assemblies available for commercial contract bids.
• Bulk & Export Packaging: Packed in rigid drop-tested master export tubes/cartons with protective film sleeves to prevent transit bending.
• Direct B2B Supply: Factory-direct volume pricing, low MOQ, and full container or LCL ocean freight from Ningbo, China.