Double-Layer Air Grille

The Double-Deflection Air Grille features two layers of adjustable blades — the outer blades arranged horizontally and the inner blades vertically (or vice versa). This configuration allows precise two-directional airflow control, providing better air distribution compared with single-deflection grilles.

Basic Construction

A standard double-deflection grille consists of the following components:

• Frame: Typically made from extruded aluminum with powder coating for durability and corrosion resistance.

• Horizontal blades (outer layer): Direct airflow left and right.

• Vertical blades (inner layer): Control airflow upward and downward.

• Optional air filter: Integrated inside for preliminary dust filtration.

With the dual-blade structure, airflow can be adjusted flexibly for spot cooling, uniform room ventilation, or to avoid direct drafts on occupants.

Operating Principle

When the HVAC system operates, conditioned air from the AHU or FCU is delivered to the double-deflection grille. The two blade layers distribute airflow horizontally and vertically, allowing either wide diffusion or directional supply depending on adjustment.

This is especially beneficial in offices, meeting rooms, and commercial spaces where stable airflow and occupant comfort are required. Proper airflow distribution also reduces drafts and prevents hot or cold spots within the conditioned area.

Types of Double-Deflection Grilles

By blade orientation

• Outer horizontal – inner vertical (most common): Suitable for flexible left-right airflow control.

• Outer vertical – inner horizontal: Used when vertical airflow adjustment is prioritized.

By installation position

• Ceiling mounted: Most common for offices, apartments, and commercial buildings.

• Wall mounted: Provides horizontal air throw, often used in server rooms or warehouses.

• Floor mounted: Less common, applied in cleanrooms or control rooms requiring upward airflow.

Selecting the correct blade arrangement and installation type is essential for optimal ventilation performance.

Key Technical Specifications

Size, material, and coating

• Standard modular sizes (e.g., 300×300, 400×400 mm) or custom dimensions

• Material: extruded aluminum or galvanized steel

• Finish: white powder coating for oxidation and corrosion protection

• Optional anodized or special coating for corrosive environments (cleanrooms, chemical plants)

Installation guidelines

Manufacturers typically recommend:

• Proper spacing from ceiling and surrounding surfaces

• Correct positioning to avoid airflow obstruction

• Optimal blade orientation to prevent drafts and airflow collision

Following installation guidelines ensures stable HVAC performance and reduces operational faults.

Selection Guidelines

Based on room size and airflow demand

• Small rooms (<20 m²): small double-deflection grille (≈300×300)

• Medium rooms (20–40 m²): medium size (400×400 to 600×600)

• Large areas or halls: multiple grilles for balanced air distribution

Airflow capacity should match the cooling capacity (BTU) to avoid weak or excessive airflow.

Installation and Maintenance

Installation procedure

1. Measure exact opening and installation location

2. Check duct airtightness before mounting

3. Install frame square and level

4. Secure grille using appropriate fasteners

5. Adjust blades for proper airflow direction

Note: Install after ceiling/wall finishing to prevent dust contamination and misalignment.

Common installation issues

• Misalignment causing incorrect airflow direction

• Installing too close to walls or ceiling restricting airflow

• Improper fasteners damaging coating

• Air leakage due to poor sealing

Such issues may reduce system efficiency by up to 15–20%.

Cleaning and Periodic Maintenance

Recommended every 3–6 months:

• Remove front grille carefully

• Clean dust with a soft brush and damp cloth

• Avoid corrosive chemicals that may damage coating

• Reinstall and reset blade position

If equipped with a filter, clean or replace periodically to maintain indoor air quality.

Benefits of Double-Deflection Air Grilles

• More uniform air distribution with fewer hot/cold spots

• Reduced draft and improved occupant comfort

• Lower noise compared with single-direction airflow

• Improved interior aesthetics when integrated with ceiling design

Recommended System Integration

For optimal HVAC performance, the grille can be combined with:

• Volume Control Damper (VCD): For airflow and pressure balancing

• Pre-filter: Improves initial air filtration

• Sound attenuator: Reduces duct noise

With flexible airflow control, durable construction, and high technical performance, the Double-Deflection Air Grille is a preferred choice for modern HVAC systems. Proper selection, installation, and maintenance ensure long-term efficiency, comfort, and energy savings.