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Table 4 shows the LETTER TO BE USED IN THE SE
GRAPH to determine the additional loss Pa in the case in
question.
PLN:
Represents the percentage of the straight line
length required for complete expansion of the air
flow leaving the fan unit
Se:
Area of the fan delivery inlet actually affected by
the air flow (value specified in manufacturer's
catalogue)
Sp:
Area of fan delivery inlet.
5.3.2.
Elbows
The FLOW RESISTANCE connected with the presence of
elbows in the ducting depends:
- on their arrangement
- on the PLN value
- on the fan unit installed
Table 5 shows the letter corresponding to the straight line
in the SE graph to be used to obtain the additional flow
resistance value Pa, depending on:
- the Se/Sp ratio
- the arrangement of the elbow (fig. 35)
- the PLN value.
TABLE 6
5.3.3.
Control air locks
Table 6 shows the MULTIPLIERS TO BE APPLIED TO THE
AIR LOCK FLOW RESISTANCE VALUES according to the
Se/sp ratio, should the locks be installed on the delivery
inlet. If the air locks are supplied by TCE consult the "SAL"
air lock technical bulletin.
Abnormal situations in relation to the reference standard
may also occur on the intake and are basically connected
with;
- the possible formation of eddies caused by curves in the
inlet conduit in conflict with the fan wheel rotation
- choking on the intake elbows
- the installation of containment housings around the fans
- more generally, the installation of accessories such as
drive protection guards, flow rate control locks, etc.
For all these evaluations and any others, all the AMCA
PUBLICATION 201 FANS AND SYSTEMS technical
documentation is available from the TCF Technical
Department. However, we would advise customers to
contact cur specialist personnel for a rapid, expert service
during inspection. The fan units will be adapted to the
new requirements by adjusting the drive ratios. In this
respect our Customer Service is always on hand to carry
out the necessary jobs.
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