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Stand
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Swirl Diffusers - 17 Pages
Acoustic Data
Example
Data given:
·
Volume flow per diffuser
V = 30 l/s
Supply air temperature differential ͬ t Z = – 8 K
Sound pressure level in room
L A = 40 dB(A)
Room height
H = 3.0 m
Required: spacing dimensions
A x B = 3.20 m x 3.20 m
Distance to side wall
X = 1.60
Flush installation in ceiling with discharge nozzle. Due to
restricted ceiling void, plenum box with side entry spigot is
required.
Diagram 1:
Sound power level and pressure drop
RFD-R-D-A /125
L WA = 37 dB(A)
ͬ p t = 40 Pa
To arrive at room sound pressure level, corrections are
required for the number of diffusers and room absorption.
11
Sound power level and pressure drop Size 400
Construction with discharge nozzle
Diagram 13:
Diffuser arrangement if B = 2.80 m
A = 3.20 m
H1 = H – 1.70 m = 1.30 m
·
At V = 30 l/s, vH1 = 0.20 m/s
Diagram 14:
Diffuser arrangement: single or more
than one row if B м 4.00 m
v H1 = 0.14 m/s
Diagram 13 applies for B = 2.80 m
and diagram 14 for B м 4.00 m
As B is given 3.20 m, interpolation is required between
the values from the above graphs
v H1 = 0.20 m/s and
- = 0.14 m/s.
v H1
This results in v H1 = 0.17 m/s
Diagram 15:
Air velocity at the wall and
temperature quotient
L = X + H1 = 1.60 m + 1.30 m = 2.90 m
A = 3.20 m
Note the line A = 3.0 m is also valid for all values above
3.0 m.
Correction to Diagram 11: Damper angle
+2
–
+2
50
45
40
35
in
dB
(A
)
W
A
L
100 l/s 150
200
300 m 3/h 500
300
400
500
900 1200 1600
Sound power level and pressure drop Size 400
Construction without discharge nozzle
50
100
W
A
20
10
L
25
30
20
in
35
dB
(A
)
40
45
50
5
50
200
70
100 l/s 150
300 m 3/h 500
200
300
400
900 1200 1600
500
45°
90°
x1
x 1.1
x 2.0
L WA
25
70
0°
ͬ pt
200
Total pressure drop ͬ p t in Pa
–
–
Correction to Diagram 12: Damper angle
20
5
50
200
10
–
–
–
+2
L W NC
20
10
·
V
x 2.3
Blade angle
30
Total pressure drop ͬ p t in Pa
50
12
90°
x 1.1
L WA
·
V
45°
x1
L W NC
100
0°
ͬ pt
200
Blade angle
–
–
+2
-
P. 1
-
P. 5
Installation • Fixing Because of their excellent performance, type RFD swirl diffusers can be installed flush with a continuous ceiling or freely... -
P. 6
Nomenclature · Quick Selection · Spectral Data·V·VA, BXH1vH1Nomenclaturein l/s:in m3/h:in m:in m:in m:in m/s:Lin m:vLͬ tZin m/s:in... -
P. 7
Example Data given: Type RFD-R-D-US/125 Volume flow per diffuser V = 24 l/s Required: Octave band sound power level of regenerated noise... -
P. 8
Acoustic Data Correction to Diagram 3: Damper angleBlade angle0°45°90°Ap,x 1x 1.2x2.4 + 1+ 3 + 1+ 3 Correction... -
P. 9
Acoustic Data Correction to Diagram 7: Damper angle Correction to Diagram 9: Damper angle Blade angle 0° ... -
P. 10
-
P. 11
Air velocity at a distance 75 mm from the wall vL = 0.21 m/s L = X+H1 = 2.90 m L = A/2 + H1 = 2.90 m AtL/Atz = 0.019 At |_ = 0.019 x (-8)... -
P. 12
Aerodynamic Data RFD 160 Diagrams 17 to 20: Permitted volume flow ranges see Selection Table Page 6. Diagrams 17 to 20 are applicable to... -
P. 13
Diagrams 21 to 24: Permitted volume flow ranges see Selection Table Page 6. Diagrams 21 to 24 are applicable to configurations with discharge... -
P. 14
Diagrams 25 to 28: Permitted volume flow ranges see Selection Table Page 6. Diagrams 25 to 28 are applicable to configurations with discharge... -
P. 15
Aerodynamic Data RFD 315 Diagrams 29 to 32: Permitted volume flow ranges see Selection Table Page 6. Diagrams 29 to 32 are applicable to... -
P. 16
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P. 17
