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Attenuation Vents | VH EMI Shielding

Attenuation Vents | VH EMI Shielding

Specifications

For gasket material specifications please refer to the K Shielding, E Shielding and S Shielding pages.

 

Performance

Frequency Field Type VH-01
10 KHz H 45
100 KHZ H 49
1 MHz H 51
1 MHz E >100
10 MHz E >100
100 MHz E >100
1 GHz P 98
10 GHz P 95

Technical Drawings

  • VH AF1 » Click to zoom ->

    VH AF1

  • VH AF2 » Click to zoom ->

    VH AF2

  • VH AF3 » Click to zoom ->

    VH AF3

  • VH AF4 » Click to zoom ->

    VH AF4

  • VH AF5 » Click to zoom ->

    VH AF5

Tolerances

Overall dimensions +/- 0.8mm
Fixing holes/fasteners +/- 0.5mm
  with jigs +/- 0.2mm

How to order

Specify: Series-Frame Style-Vent Media-Overall Size-Number 0f Fixings-Fixing Type/Size
Where possible please provide a detailed drawing.

Shielding Series Frame Style Vent Media Overall Size Fixings (No.) Fixing Type
VH-Vent AF1 01=Cross-pole xxxx-xxxx xx C/T=Captive insert
Aluminium AF2 02=single layer     T/H=Through hole
  AF3 03=slant 45°      
  AF4 04=slant cross      
  AF5 pole      

Examples / Notes

Example:
VH-AF1-01-2260-4330-12-T/H (4.8) specifies an aluminium cross-polarised vent panel in AF1 frame style with 12 through holes of 4.8 mm diameter. Hole positions to be agreed with the customer prior to manufacture or as shown on the customer drawing.

For aluminium vent panel types and styles not shown please contact us or forward a detailed drawing for quotation.

Dustfiltration

Demountable dustfilters are available for use with attenuation vents and are featured in the VB Shielding section. They are generally produced using the AF1 or AF5 frame styles and can be mounted with quick-release fasteners for ease of cleaning or replacement.

Download the Attenuation Vents Range as a PDF

General Information

Our VH Shielding lightweight aluminium honeycomb attenuating ventilation panels comprise of forms of conductive airflow media retained within an aluminium extrusion. These EMC vents are designed for use in racks and other forms of commercial enclosure.

Applications

Our VH Shielding EMC vents can be mounted onto most forms of shielded enclosure where airflow is needed, either over cooling fans or by convection. They can be mounted anywhere on the enclosure and can be fitted with protective 'kickplates' to protect the honeycomb material from accidental damage.

Where they may be exposed to the elements the vents can be fitted with 'slant' honeycomb which provides a downward facing aperture, preventing the ingress of rainwater. This has the added benefits of directional airflow and increased attenuation due to the higher aspect-ratio of the cell structure.

Honeycomb ventilation panels are usually supplied with gaskets in a ready-to-mount form which either fits around the aperture in the equipment (non-flanged style) or is inset into the enclosure (flanged style). Depending on the performance requirements for the application, they can be mounted by bolting through clearance holes in the frame, through the use of captive or threaded inserts.

Aluminium honeycomb material is formed by expanding a bonded aluminium foil into a honeycomb structure. This process, which is common to all honeycomb manufacturers, produces a material which is 'polarised' and is conductive either horizontally or vertically. To overcome polarisation problems two layers of honeycomb, mounted at 90 degrees to each other, are used. Please contact us for futher information about polarisation.

Each cell in an attenuation vent acts as a waveguide and its performance is a function of its width/height and the ratio between the depth and width of the cell. Generally an aspect ration of 4 or 5:1 is used.

VH shielded vents are finished to suit specific applications and can be protected by Alocrom 1000, 1200 or electroplating. We can also offer an Iridite conversion which is RoHS compliant.