Products: Attenuation Vents | VH Series
General Information
Our VH Series of 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 Series of 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 usually supplied in a gasketed 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 vents are finished to suit specific applications and can be protected by Alocrom 1000, 1200 or electroplating. We can also offer a chromate conversion which is RoHS compliant.
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 (click on drawings to zoom)
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VH AF1
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VH AF2
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VH AF3
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VH AF4
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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.
| 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 Series 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.
