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5.2.4.
Humidification system check
- Check that the humidification system is functioning
correctly, and particularly the exact humidistat or
regulator electrical connection to ensure that the system
comes into operation if the relative humidity in the
environment drops in relation to the set-point, and vice
versa. As with every other control feature, you must
therefore simulate different values on the regulators or
humidistats to check the activation of the pump, the
submerged electrode steam generator or any other
component involved in the treatment
- Check the correct siphoning of the drains (section 4.4.).
5.3. CORRECTION OF FLOW RESISTANCE VALUES IN
CIRCUITS AND ADJUSTMENT OF FAN AIR-MOVING
PERFORMANCE
MODIFICATIONS TO THE AIR-MOVING CIRCUIT may
sometimes be necessary during installation as a result, for
example, of dimensional or routing requirements that
cannot be anticipated at the design stage.
These modifications frequently result in increasing the
number and type of factors that affect fan performance.
Hence the need to approximate as realistically as possible
the
SYSTEM
CHARACTERISTIC
recalculating the new flow resistance values and
introducing e correction factor.
On the basis of its thirty years' experience in the field, TCF
Technical Department uses and recommends the SE
(SYSTEM EFFECTS) ADDITIONAL FLOW RESISTANCE
SYSTEM based on the charts developed by AMCA (AIR
MOVING AND CONDITIONING ASSOCIATION).
To calculate the additional flow resistance a graph is used
which presents a family of straight lines on logarithmic
velocity/flow resistance coordinates. Each line, which is
identified by a different letter of the alphabet, represents
an abnormal situation that determines an additional flow
resistance.
AMCA lists the adverse installation situations and
indicates the letter corresponding to the straight line in
the SE graph with which to determine the additional loss
factor. The flow losses Pa are calculated on the SE graph
as follows:
- enter the x-axis
• with the fan output velocity V if the obstruction is on the
delivery side
18
CURVE,
accurately
• with the fan input velocity V if the velocity refers to the
intake side
- ascend vertically to the straight line representing the
abnormal installation situation
- move horizontally to the y- axis to read off the Pa value.
5.3.1.
Insufficient length of diverging duct section
between unit delivery inlet and obstruction
In the event that a given accessory has been installed at
such a distance from the delivery inlet as not to allow the
complete expansion of the air flow in the duct, abnormal
conditions quantifiable using the SE METHOD may arise.
In order for the air flow to expand and occupy the entire
duct section, a straight line distance is required equal to:
L>= 2.5 equivalent diameters (low/medium velocity ducts
L >= 6 equivalent diameters (high velocity ducts with V
>= 30 ITT/S)
Table 3 shows the value of the equivalent diameters for
rectangular ducts.
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