Attenuation Vents0 pages

OurVH Shielding range of lightweight aluminium

honeycomb attenuating ventilation panels

comprise of forms of conductive airflow media

retained within an aluminium extrusion. They are

designed for use in racks and other forms of

commercial enclosure.

14

VENTSHIELD Attenuation Vents

VH Shielding

Applications:

Lightweight aluminium honeycomb 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 befitted with protective'kick-plates'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, prevent-

ing 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 to be 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 or

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

'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 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 ratio of 4:1 or 5:1 is used.

Aluminium honeycomb 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.

Specifications:

For gasket material specifications please refer to knitted mesh gaskets

(pages 4-13), oriented wires in silicone gaskets (pages 20-22) and

conductive silicone gaskets (pages 39-42).

Performance: Typical Attenuation dB

1 m-rtMUiOGT ^

P&PTechnology Ltd

1-3 Finch Drive

Springwood Industrial Estate

Braintree CM7 2SF

T:+44 (0)1376 550525

www.p-p-t.co.uk

FREQUENCY

10 KHz

100 KHz

1 MHz

1 MHz

10 MHz

100 MHz

1 GHz

10 GHz

FIELD

H

H

H

E

E

E

P

P

ATTENUATION

45

49

51

>100

>100

>100

98

95