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Download Product Catalogue for AEROVAC NON RETURN DAMPER (NRD)


AEROVAC Non Return Dampers are designed for automatic shutoff of Individual sections of the air conditioning system. With the fan running, the degree of blade opening is a function of air velocity. If the fan is turned off, the blade will close automatically. In a multi fan installation system this prevents back draught through the non operating fan.

AEROVAC NRD type model are also called Self Closing Damper or Gravity Damper or Pressure Relief Damper The blades are smooth, reliable and designed for energy saving.

These are air operated, opening or closing dampers for intake, discharge and pressure relief vents in air conditioning systems. Designed to maintain a constant air pressure level inside pressurized rooms.


  1. Smooth and maintenance free blade operation.
  2. The frame is manufactured from high quality aluminium / galvanized sheet steel of 18 gauge thickness.
  3. Blades are made of 0.3 mm / 1.00 mm thickness aluminium sheet or galvanized steel sheet.
  4. Blades are fitted with nylon bushes for rattle free and smooth operation.
  5. Blades are sealed with foam / rubber gasket at the bottom to avoid rattling noise and provide air tight operation.
  6. Frame is fitted with aluminium strip to prevent the over movement of the blades.
  7. Additional centre partition shall be provided if height or length is more than 900 MM.

Standard Models

  1. AEROVAC NRD IW : Internal Wall Mounting
  2. AEROVAC NRD RD : Round Duct Mounting
  3. AEROVAC NRD SD : Rectangular Duct Mounting.
  4. AEROVAC NRD EW : External Wall Mounting

The non-return damper varieties are assembled in a way so as to cause the automatic shutoff of different sections of the air conditioning system. While the fan keeps running, the extent to which the blade opens depends on the velocity of the air.

If the fan is turned off, the blade will close automatically. In a multi-fan installation system, this prevents back draught owing to the non-operating one.

The NRD type model is also called the self-closing damper, gravity damper, or pressure relief damper.

The blades are smoothened and made from reliable materials that are designed to save as much energy as possible.


Air duct dampers are air operated, relying on opening or closing mechanisms for intake, discharge and relief vents in the conditioning systems. They are meant to maintain a constant pressure level inside pressurized rooms.

Air Damper Component Features

The devices are equipped with several practical features that are a culmination of the best engineering and manufacturing processes, along with high quality materials.

Air Damper Equipment

The blades are smooth and make use of a maintenance free structure, while the frame is made from high quality aluminum or galvanized steel sheet with an 18-gauge thickness.

It is also fitted with aluminum strips to prevent blades from moving more than they are meant to.

Blades are made from aluminum or galvanized steel sheets with a thickness of 0.3 mm and 1.00 mm. The nylon bushes, which play a part in rendering a rattle-free and smooth operation.

They are also sealed using foam or rubber gaskets at the bottom, to prevent a rattling noise and render a calm and airtight operation.

An added center partition can be provided if the height or length of the structure is more than 900 mm.

Air Damper Models

The inventory of our air duct damper in Dubai and GCC region offers four different variants.

The Aerovac NRD JW and NRD EW are both wall-mounted devices, placed internally and externally respectively.

The Aerovac NRD RD and NRD SD devices are duct mounted, with the former meant to be placed in round ducts, and the latter meant for rectangle shaped structures.

Duct mounted non-return dampers (NRD)

These devices are designed to be placed in fresh air intake or air exhaust openings, with twin fans in commercial and residential premises.

Non-return dampers prevent the air from flowing in reverse, and shield against the entry of undesired and foreign elements, such as polluted air, rain or birds into the HVAC system.

Wall mounted non-return dampers (NRD)

Wall mounted non-return dampers carry out essentially the same function as duct dampers. They also prevent the air from flowing backwards, and block the interference of unwanted elements across one side to the other.

The key difference is that they are fixed onto walls, working mainly to keep elements out of a room, while the versions placed in ducts work to make sure the HVAC system functions properly.

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