Non-Return Dampers - Marine & Offshore Ventilation Solutions
Prevent Backflow with Professional-Grade Non-Return Dampers
Non-return dampers are essential components in marine and offshore ventilation systems, preventing dangerous backflow that can compromise air quality, fire safety, and equipment operation.
As an authorized distributor of leading manufacturers including Halton, Knape Associates provides comprehensive non-return damper solutions for critical marine applications.
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Understanding Non-Return Damper Technology
Non-return dampers operate on a simple yet effective principle: gravity-operated blades automatically close when airflow pressure drops below the minimum opening threshold.
This passive operation requires no electrical power, actuators, or motors, making these devices extremely reliable in demanding offshore environments.
The damper blades feature counterweight systems that can be adjusted to set the minimum opening pressure, typically starting at 30 Pa. When sufficient positive pressure exists, blades open in parallel to allow normal airflow with minimal pressure loss.
When pressure drops or reverses, the weighted blades immediately close and seal the ductwork using integrated silicone seals.
Key Features and Performance Benefits
Installation Options: Available for both rectangular and circular ductwork in horizontal or vertical orientations.
Rectangular units accommodate widths from 150mm to 1200mm and heights from 150mm to 1400mm. Circular models range from 100mm to 1250mm diameter, with modular construction available for larger applications up to 2400mm x 2800mm.
Robust Construction: Frame materials include painted carbon steel, hot-dip galvanized steel, and stainless steel grades 304, 316L, and 316L (EN 1.4432). Blade assemblies feature dual-sheet sandwich construction with 0.8mm thickness per sheet.
Maintenance-free stainless steel bearings ensure long-term reliability, with bronze bearing options available for specific applications.
Marine-Grade Performance: Standard temperature operation up to 100°C with high-temperature options available to 180°C. Maximum duct pressure rating of 5000 Pa and air velocity limits of 15 m/s accommodate most marine ventilation requirements. Units achieve leakage class ratings up to Class 2 per EN1751:2014 standards.
Explosion-Proof Certification: ATEX and IECEx certified models available for hazardous area installations common in offshore oil and gas operations.
Critical Marine Applications
Fire Safety Systems: Non-return dampers prevent smoke and fire spread through ventilation systems during emergency conditions. Proper installation ensures fire-rated barriers maintain their integrity.
Engine Room Ventilation: Prevents contaminated air from engine spaces from entering accommodation areas or other clean zones during ventilation system shutdowns or reversals.
Cargo Hold Protection: Maintains proper pressurization in cargo areas and prevents cross-contamination between different cargo spaces.
Emergency Ventilation: Ensures emergency ventilation systems function as designed by preventing backflow that could compromise escape routes or safe areas.