11
ORIGINAL INSTRUCTIONS
VES Andover Ltd Eagle Close Chandlers Ford Ind. Est Eastleigh Hampshire SO53 4NF
Tel: 08448 156060 Fax: 02380 261204 E-mail: [email protected] Web: www.ves.co.uk
Acoustic Supply Unit
Installation, Operation and Maintenance Manual
®
Continued
As all units in the
Colourfan acoustic
range feature tapped inlet rings it is possible to establish
the volume flow rate by measuring the static pressure rise into the fan.
The centrifugal fans have infinite speed adjustment, the benefits of real energy savings are
apparent when the fan speed is reduced; this is best demonstrated when used in conjunction
with additional sensors such as air quality or occupancy.
Using a micro manometer and adjusting the fan speed it is possible to commission each fan to
the required air volume. Each fan section has a differential pressure tapping connection point;
by connecting your micro manometer to the appropriate pitot a differential pressure reading
can be taken. This measurement can then be applied to the calculation as below or by using the
differential pressure curve on page 12 Fig.
19
. Simply read across from the pressure measure-
ment to the fan curve and down to calculate the resultant air volume.. If the unit features a
fitted control panel this action can be undertaken within the programming available; see the
accompanying controls documentation for further operational details.
Example:
Measured differential pressure: 350 Pa
This measurement can then be expressed in the following calculation:
where
q
V
is the air volume in m³/s
k is the fan nozzle coefficient (Fig.
18
)
p
W
is the measured differential pressure in Pa
Measured differential pressure: 350 Pa
q
V
= (96 350) / 3600
q
V
= (86 x 18.708) / 3600
q
V
= 1796 / 3600
q
V
= air volume = 0.5 m³/s
Standard Wiring
& Fan Installation
5
Differential pressure
calculation
K Chart
Fan nozzle coefficient
Fig.
18
q = (k
p ) / 3600
V
W
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