Dust-Measurement - Paul Gothe GmbH

11. Sampling points in circular and rectangular ducts
Circular ducts
There are two methods for determining the position of sampling points in circular ducts as described in C.1.2 and C.1.3.
Both methods are considered equivalent.
In the "general method" applicable to circular ducts, the sampling plane is divided into equal areas. The sampling
points, one at the centre of each area, are located on two or more diameters (sampling lines), and one point at the
centre of the duct (see Figure C.1).
Figure C.1 — Sampling point positions in circular ducts - General method
(showing positions for ducts over 2 m in diameter -
The shaded positions are of equal area)
The locations of the sampling points are dependant on the number of sample points chosen.
For circular ducts two sampling lines (diameters) are sufficient, the distance can calculate by the formula shown in our
data sheet
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