Our lightweight aluminium honeycomb attenuated ventilation panels are available with a choice of 13 standard aluminium frame extrusions. These EMI shielded vents are designed for use in racks and other forms of commercial enclosure.
Standard products
EMI shielded vents
Our lightweight aluminium honeycomb attenuated ventilation panels are available with a choice of 13 standard aluminium frame extrusions.
Applications
Lightweight aluminium honeycomb vents can be mounted onto most forms of EMI 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 aluminium honeycomb 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 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 ‘polarized’ 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 further 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.
Aluminium honeycomb vents are finished to suit specific applications and can be protected by Alocrom 1000, 1200, Iridite or electroplating.
Detailed information
Specifications
For gasket material specifications please refer to the knitted mesh gaskets, conductively loaded silicone and oriented wires in silicone pages.
Performance
| Frequency | Field | Type AF1 | Type AF2 | Type AF5 | Type AF9 | Type AF12 and AF13 |
|---|---|---|---|---|---|---|
| 10KHz | H | 45 | - | 40 | 33 | 51 |
| 100KHz | H | 49 | *77 | 43 | 37 | 57 |
| 1MHz | H | 51 | - | 47 | 39 | >105 |
| 1MHz | E | >100 | - | 84 | 43 | >105 |
| 10MHz | E | >100 | - | 97 | 84 | >105 |
| 100MHz | E | >100 | 56 | >100 | 79 | >105 |
| 1GHz | P | 98 | **96 | 85 | 50 | >105 |
| 10GHz | P | 95 | 80 | 85 | 60 | ***90 |
Figures for AF1 – 2 layers 6.3mm thick honeycomb 3.2mm cell size at 90° (cross pole) with Alochrom 1200 finish
Figures for AF2 – single layer 12.7mm thick honeycomb 3.2mm cell size with Alochrom 1200 finish
Figures for AF5 – 2 layers 3.2mm thick honeycomb 3.2mm cell size at 90° (cross pole) with Alochrom 1200 finish
Figures for AF9 – single layer 6.4mm thick honeycomb 3.2mm cell size with Alochrom 1200 finish
Figures for AF12 & AF13 – 2 layers 12.7mm thick honeycomb 3.2mm cell size at 90° (cross pole) with Alochrom 1200 finish
Tests to MIL STD 285 (modified)
*figures for 200KHz
** figures for 2GHz
***figures for 10GHz-18GHz
Tolerances
| Overall dimensions | +/-0.8mm |
|---|---|
| Fixing holes/fasteners | +/-0.5mm |
| with jigs +/-0.2mm |
How to order
Specify: Shielding 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 | |||
| AF3 | 03 = Slant 45o | ||||
| AF4 | 04 = Slant cross pole | ||||
| AF5 | |||||
| AF6 | |||||
| AF7 | |||||
| AF8 | |||||
| AF9 |
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 Vent / Filter Composite section. They are generally produced using the AF1, AF2 or AF5 frame styles and can be mounted with quick-release fasteners for ease of cleaning or replacement.
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Many of our clients require bespoke made products. If you'd like to discuss a product, please do give us a call and speak to us about your requirements.