Where to buy air sampling probe? -Reply

[FRAMEP@ORAU.GOV]

Wes Van Pelt wrote in part:

>I wonder if anyone knows of a commercial source for air sampling
>probes.  Let me explain further.  What I am looking for is a simple
>pipe which permanently goes into a stack or duct which will draw a
>continuous isokinetic air sample from the duct.  This is not much
>more than a pipe with a 90 degree bend and a flange or other
>mounting bracket.  They would have to come in a range of inner
>diameters so that isokinetic flow could be reached within the
>desired sample air flow range.

Wes:

There are several companies that you could contact (btw I don't mean
to recommend these or imply anything by leaving someone of this
list). 

BGI Inc. Waltham Mass. (617) 891 9380
They sell the buttonhook nozzles geared to the EPA standard methods.
I don't know if they sell the mounting flanges.

Kurz, Monterey, CA (408) 646 5911 or (800) 424 7356 has probes and
mounting brackets but these might only be sold as part of a system.

Graseby-Anderson, Atlanta GA (404) 691 1910. They are about to market
a shrouded probe which reduces particulate losses in the nozzle and
does not require isokinetic sampling. This is a sufficiently new
concept that you would want to be sure that you have all the "powers
that be" on board. They sell other equipment as well. 

A few comments wrt to building one. 

Don't make it so permanent an instalation that it can't be removed on
a regular basis for inspection and analysis.

Consider some design feature (eg a positive stop) that will ensure
the probe is facing directly into the air stream and will not twist.

Since you mention isokinetic sampling, the implication is that
particulates will be collected.  As such, a "pipe with a 90 degree
bend" would be a no no. It would be best to have a nice gradual
curve, say with a radius of curvature greater than 5 times the things
diameter (an old rot).

The nozzle opening should be sharp with a bevelled angle less than 30
degrees. This kind of edge would not be needed with a shrouded probe
however. 

The inside of the nozzle should be as smooth as possible. 

Best of luck

Paul Frame
Professional Training Programs
Oak Ridge Institute for Science and Education
framep@orau.gov