10
Each tubing run should be the same length,
±
20%. For example, having the manifold only 10 feet
from the nearest sampling point and 90 feet from the farthest will create imbalances in the system
which may adversely affect sampling.
Tubing Connections
The isokinetic probes you received with your order should be protected with plastic caps on the
openings, which should remain in place until they are ready to use in order to minimize
contamination . Install the isokinetic probes at the desired points, and select a position for the A2432
system equipment less than 100 feet (including vertical runs) from every sampling point. Verify that
adequate power is available for this equipment, and make sure that the counter and controller front
panels will remain accessible.
When the sample tubing is cut to length, cover the ends until ready to attach it to the equipment at
either end, to minimize system contamination. Connect the sample tubing to the isokinetic probes
and route the tubing to the manifold equipment without kinking. Any bend in the tubing can affect
the particle size distribution at the particle counter because the larger particles are heavier and may
drop out in bends or loops. Each bend radius should be no less than four inches and care should be
taken to avoid potential kinks at any point along the tubing where it is anchored to a clip or other
hold-down device. Fully support the tubing wherever possible and do not drape the tubing across any
sharp cornered objects where later heat induced sagging may cause pinching or kinking.
Connect the tubing to the manifold system equipment referring to figures 2 and 3 , following these
steps:
1. Connect all sample tubing (3/8" I.D.) to the appropriate manifold ports. If only a few
manifold ports are to be used, connect the sample tubing to ports spaced proportionately. For
example, five samples should be connected to ports 1, 7, 13, 19 and 26. This will keep the
airflow in the manifold balanced. Unused ports need to be left open to relieve the excess
vacuum load on the pump, or the relief valve on the pump must be adjusted according to the
pump manufacturers instructions. For further explanation of the airflow in the manifold, refer
to the “Theory of Operation” section of this manual.
Figure 2.
Manifold to Sample Point Tubing Connections
Sample ports (up to 32)
Isokinetic Probes
to
