Dan,
One advantage to giving advice that is outside of the realm of my core
competency is that if I make a fool of myself I hopefully won't get flamed too
bad (Harmonics anyone?)
I am familiar with SCFH (standard cubic feet per hour), SCFM (standard
cubic feet per minute), and LPM (liters per minute); if LFM is a similiar unit
of volumetric flow rate I think I can help. I am also assuming you want to
provide a controllable amount of flow rather than measure the existing flow in
your product. If this is the case you should be able to use a flowmeter. This
is a vertical column, with a tapered ID (internal diameter) and a small ball
inside. when air flows through it the ball rises and the flow rate is read from
markings on the outside of the column. Dwyer makes them; and if you are like
many engineers of my acqaintance and coudn't resist a free 20 lb. library from
Omega (especially when they started throwing in Dilbert cartoons), you can see
an example of one in the flow and level volume.
Most flowmeters of this type have pipe thread fittings or barb type
connectors. They also have a knob on the front for a needle valve to control
the flow. If you connect the inlet with tubing to a source of compressed air
(regulated) and run the outlet tubing into your unit you will have a
controllable air flow. If your product has numerous air slots tape the end of
the tubing to one and tape over all other inlets and openings (except the exit)
so all the air flows through your unit and out the desired exit. If you do not
have inlet slots or you want to bring the flow closer to the internal part of
concern you can lift a portion of the case and feed the tubing through using
tape to seal the seam. You should have a diffuser at the end of the tube (or
aim it at a diffusing structure already present to prevent direct impingement
of the high velocity air stream on to the part(s) of concern (trust me, you DO
NOT want to hear an EMC engineer try to talk knowledgably about enthalpy,
entropy, or those other fun heat transfer and fluid flow terms).
If you are more concerned with the air flow around your product than
through your product as it seems you might be from your original message, the
job is easier (or at least requires less tape). In this case you build a box to
put your product in. Attach a fitting to the box for the outlet tubing from the
flowmeter and add some exit ports at the opposite end of the box for the air to
exhaust.
If this helps you I am :
Paul McCoy
emmas...@execpc.com
If this is useless information I am:
some worthless hacker, stealing the web identity
of a fine engineer to drag his name through the mud
Dan Mitchell wrote:
> My company produces AC to DC Power Supplies. I have been directed to make
> a quick and dirty test rig that will allow me to put a predetermined
> airflow in LFM over the unit. Does anyone know of a website that describes
> something like this or have had experience building such a test rig and
> would be willing to share their expertise.
>
> Daniel W. Mitchell
> Product Safety Associate Engineer
> EOS Corp.
>
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