Joe
The type of airflow measuring kit you have mentioned is a Hot Wire Anemometer.
Starting price around $300. They will give you an air velocity reading in m/s or
ft per min. You will not get be able to get a true cubic ft per minute reading
using this type of device. For that you need a full blown air flow rig with with
back pressure compenstation and know measurement apparatus sizes. A lot more
than £300.
But the Hot WIre Anemometer can be a very handy and easy to use tool. Basically
it has a small constant area aperture on the end of a probe. Sitting in the
middle is a hot resistor kept at a constant temperature. As the airflow
increases, the amount of current required to keep the resistor at this
temperature increases, and then the equipment does the smart bit of relating
this current to air velocity.
An important things to note about using one of these devices is to keep the
angle of the aperture, relative to the air flow constant. A change of a few
degrees can introduce large measurement errors if your air flows are low. This
can be seen by simply rotating the sensor head in an airflow and recording the
variation in readings.
If you want to get an approximate air flow reading. You can extend a tube out
form the slot and by placing the anemometer in the middle, get a reading for
velocity through a known area. But this reading will only be an approximate as
no account is taken for boundary layer effects of your tube or the presence of
the sensor head. Nor will you be certain of the air velocities at the corners if
you are measuring the air flow form a non circular slot.
But for a generally investigation of air flows across a product, a very useful
tool.
Joe Finlayson wrote:
> I'm interested in doing an air flow analysis on a per-slot basis for
> a modular chassis. Can anyone share their experience in using their
> favorite test tools for this function. One of my colleagues had mentioned
> that he recalls the use of a thermocouple-type lead that was used at his
> previous place of employment that measured air flow. Any knowledge of this
> type of product would be greatly appreciated as well.
>
> Thx,
>
> Joe
>
> *********************************
> <<...>>
>
> Joe Finlayson
> Manager, Compliance Engineering
> Telica, Inc.
> 734 Forest Street, Bldg. G, Suite 100
> Marlboro, MA 01752
> Tel: (508) 804-8212
> Fax: (508) 480-0922
> Email: jfinlay...@telica.com
> Web: www.telica.com
>
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--
Andrew Carson - Product Safety Engineer
Xyratex Engineering Laboratory
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