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SWIRL
DIFFUSERS

Swirl diffusers are ideal for use on heating and cooling applications, particularly where the mounting height is between 2.7 and 4 metres. The diffusers have a high induction rate and are suitable for constant volume and variable volume systems with a turn down in airflow rates from 100% to 50%. The blades on some models can be manually adjusted to give either horizontal or vertical discharge. This adjustment also enables the unit to handle larger volumes of air, size for size. Similarly, the larger the number of slots, the larger the air volume that can be handled, size for size.

STANDARD •
(Fixed Blade)
Code 0550. Swirl in a square panel. Not tile replacer sizes.
Code 0551. Swirl in a square tile replacer panel,
595mm x 595mm.
Code 0558. Swirl in a circular panel. Flush face.
Code 0557. Swirl in a circular panel. Dished face.

(Manually adjustable blades)
Code 0560. Swirl in a square panel. 24 slots.
Code 0561. Swirl in a square panel. 16 slots.
Code 0563. Swirl in a circular panel.24 slots.
Code 0564. Swirl in a circular panel. 16 slots.

(Combination Unit, Adjustable outer. fixed inner blades).
Code 0555. Swirl in a square panel.
Code 0556. Swirl in a circular panel

 

 

 

STANDARD SPECIFICATION

SIZES
The nominal size and full product code of a swirl
diffuser is based on the nominal diameter of the blade area. Codes 0561 and 0564 have three panel sizes for
the same nominal diameter and so there is a suffix, L,
M or S to differentiate between them in each case.

Code 0550.
Nominal Dia mm 125 160 200 250 315 355 400
Panel 171 sq 213 sq 264 sq 326 sq 405sq 475 sq 530sq

Code 0551.
Nominal Dia mm 125 160 200 250 315 355 400
Panel 595 sq 595 sq 595 sq 595 sq 595 sq 595 sq 595 sq

Code 0558. Nominal Dia mm 125 160 200 250
315 355 400
Panel Dia mm 191 226 290 346 421
518 612

Code 0557. Nominal Dia mm 160 200 250 315
Panel Dia mm 247 287 337 402

Code 0560. Nominal Dia mm 570
Panel Size mm 595sq

Code 0561. Nominal Dia mm 370
Panel Size mm 395sq(L) 495sq(M) 595sq(S)

Code 0563. Nominal Dia mm 570
Panel Dia mm 595

Code 0564. Nominal Dia mm 370
Panel Dia mm 394(L) 494(M) 594(S)

Code 0555 Nominal Dia mm 570
Panel Size mm 595 sq

Code 0556. Nominal Dia mm 570
Panel Dia mm 595

CONSTRUCTION
Manufactured from mild steel with blades formed in steel.

FINISHING
Powder coated white (RAL 9010 gloss) with adjustable blades in black and fixed blades in white (RAL 9010).

FIXING
Fixed blade models are normally secured through the neck into the duct or plenum. (Fixing type OF7). However, if access is not available above the ceiling, they can be supplied with a central hole punched in the face and a fixing screw that would locate into a
mounting bridge. (Fixing type OF10). The product code prefix also becomes 9 instead of 0. It is important that this is requested at the time of ordering as the hole and screw are not standard. The mounting bridge is an addition. See optional alternatives/additions below. Adjustable blade and combination models are secured by a central bolt through the face of the
diffuser which locates into a mounting bridge. (Fixing type OF10). The central screw is provided with the
diffuser. The mounting bridge is an addition. See optional alternatives/additions below.

PACKAGING
Each diffuser is individually shrink wrapped in polythene with additional cardboard support to the faces.

TECHNICAL INFORMATION
Codes 0550, 0551, 0557and 0558 see pages 33 - 37
Codes 0560, 0561, 0563 and 0564 see pages 38 - 42
Codes 0555 and 0556 see page 43

Plenum boxes and transformation pieces.
Un-insulated.

Code 0520. Side entry plenum box with quadrant damper in the spigot for a Code 0550 or 0551 fixed blade square panel swirl diffuser.

Code 0521.Side entry plenum box with quadrant damper in the spigot for a Code 0557 fixed blade
circular panel dished face swirl diffuser.

Code 0522.Side entry plenum box with quadrant damper in the spigot for a Code 0558 fixed blade
circular panel flush faced swirl diffuser.

Code 0523.Side entry plenum box with quadrant damper in the spigot for a Code 0555, 0560 or 0561 adjustable or combination blade square panel swirl
diffuser.

Code 0524.Side entry plenum box with quadrant damper in the spigot for a Code 0556, 0563 or 0564 adjustable or combination blade circular panel swirl diffuser.

Code 0525.Circular transformation piece for a Code 0556 combination blade swirl diffuser to give an
in-line reduction in neck size from 594mm to 300mm.

Insulated.
Contact Head Office for details.
Details are shown in the Sheet Metal Work section.

MOUNTING BRIDGE
A mounting bridge is necessary with the adjustable and combination blade units. One will also be required with the fixed blade model for fixing type OF7. The product codes are as follows:

Fixed blade models. Code 0526.
Adjustable blade models. Code 0527.
Combination models. Code 0528.

The last four digits with or without L, M, S suffix in the part code denote the nominal size of the unit that it is to be used with.

QUADRANT DAMPER
A manually operated quadrant damper (Code 0483) can be fitted into the spigot of the plenum box..

FINISHES
Any BS or RAL powder coat finish can be applied but not stove enamel. Code 0145 please specify colour.

ORDERING DETAILS

• The code for the basic diffuser should have 13 digits.
See page 1.
• Add codes for additions/alternatives as suffixes.

EXAMPLE:
A fixed blade swirl diffuser in a square panel 595 x 595 mm in RAL 9010 with a plenum box and
quadrant damper in the spigot would be coded 055l/00595/0595+0520+0483

Applications. Supply * Ceiling *



TECHNICAL INFORMATION ON CODES 0550, 0551, 0557 & 0558
(SELECTION EXAMPLE)

• Air diffusion by means of swirl diffusers forms an important innovation in comparison with traditional ceiling diffusers, especially with respect to its high induction capacity. The rotational turbulence produced, causes a rapid mixing of supply and induced air, resulting in rapid mixing of temperatures and considerably shorter jet throws.

• This type of diffuser can be used in both constant and variable volume systems, allowing for variations in airflow rate from 100% to 50% without risk of jet detachment. A high air change rate can be obtained in the room with temperature differences from +12°C to
-12°C.

• Swirls diffusers with manually adjustable blades should preferably be used for heights between 2.7
and 4m. They can satisfy practically all air diffusion requirements, both in comfort and industrial
applications.

General notes on the quick selection graphs

• The examples in the selection graphs are based on
the diffusers.

• Being mounted in line with the ceiling and not in
a free space application.

• Room height is 3 ± 0.5m.

• Sound index NR is based on sound power, without
room attenuation and without damper.

Example of selection

• Once the total supply air flow rate, room
dimensions and maximum permitted noise level are defined, the required number of diffusers can be
determined for optimum comfort conditions, by using the following procedure.

Room: 8m x 8m x 3m (square)
Total air flow rate: 0.306m3/s (306 l/s)
Max. permitted noise level: NR 40
Max. Velocity in occupied zone: 0,20m/s
Diffuser type: 200 Nominal Size.

Procedure
With the occupied zone up to 1,8m from the floor height difference will be 3 - 1.8 = 1.2m. With this value the corresponding graph (see page 34) can be entered so as
to find the intersection between h dif. and Vt.

The next step consists of defining the maximum
airflow rate for each diffuser, without exceeding the specified noise limit (NR 40).

In the graph for the flow rate/pressure/noise level
corresponding to this diffuser type, it can be found that the airflow rate for NR 40 is 0.076m3/s.

Dividing the total airflow rate for the room by the flow rate per diffuser we obtain 0.306 / 0.076 = 4
diffusers. Distributing the diffusers symmetrically, 4 diffusers can be installed at a distance of 4m between axes and 2m to each wall. The maximum throw for each diffuser should not exceed 2m.

In the graph on page 34 the airflow rate can be found for which this condition will be satisfied: Having defined the maximum airflow rate for acoustical
reasons to be 0.076m3/s, it can be seen that at this flow rate, at a distance of 1,2m from the ceiling a maximum velocity in the occupied zone of 0,20 m/s will be obtained with a throw X of 2m.

The nominal airflow rate per diffuser will be:

3.306 / 4 = 0.0765m3/s.

Example of selection

0.076m3/s
Airflow / Pressure / Noise Levels
Q(m3/s) = Airflow rate in metres cubed per second
Ps (Pa) = Pressure loss in Pascals




 

• Air diffusion by means of swirl diffusers forms an important innovation in comparison with traditional ceiling diffusers, especially with respect to its high induction capacity. The rotational turbulence produced, causes a rapid mixing of supply and induced air,
resulting in rapid mixing of temperatures and
considerably shorter jet throws.

• This type of diffuser can be used in both constant and variable volume systems, allowing for variations in airflow rate from 100% to 50% without risk of jet detachment. A high air change rate can be obtained in the room with temperature differences from +12°C to
-12°C.

• Swirls with manually adjustable blades should be used for heights between 2,7 and 4m. They can satisfy practically all air diffusion requirements, both in
comfort and industrial applications.

General notes on the quick selection graphs

• The examples in the selection graphs are based on the diffusers.
• Being mounted in the ceiling and not in a free
space application.
• Room height is 3 ± 0.5m.
• Sound index NR is based on sound power, without room attenuation and without damper.

Example of selection

• Once the total supply air flow rate, room
dimensions and maximum permitted noise level are defined, the required number of diffusers can be
determined for optimum comfort conditions, by using the following procedure.

Room: 20m x 20m x 3m (square)
Total air flow rate: 3.056m3/s (3056 l/s)
Max. permitted noise level: NR 35
Max. Velocity in occupied zone: 0,25m/s
Diffuser type: Code 0560 or 0563

Procedure
With the occupied zone up to 1,8m from the floor
the height difference will be 3 - 1,8 = 1,2m. With this value the corresponding graph (see page 40) can be entered so as to find the intersection between h dif. and Vt.

The next step consists of defining the maximum
airflow rate for each diffuser, without exceeding the specified noise limit (NR 35).

In the graph for the flow rate/pressure/noise level
corresponding to this diffuser type, it can be found that the airflow rate for NR 35 is 0.19m3/s.

Dividing the total airflow rate for the room by the flow rate per diffuser we obtain 3.056 / 0.19 = 16
diffusers. Distributing the diffusers symmetrically, 16 diffusers can be installed at a distance of 5m between axes and 2,5m to each wall. The maximum throw for each diffuser should not exceed 2,5m.

In the graph on page 40 the airflow rate can be found for which this condition will be satisfied: Having defined the maximum airflow rate for acoustical
reasons to be 0.19m3/s, it can be seen that at this flow rate, at a distance of 1,2m from the ceiling a maximum velocity in the occupied zone of 0,23 m/s will be obtained with a throw X of 2,5m.

The nominal airflow rate per diffuser will be:

3.056 / 16 = 0.19m3/s.



Symbols:
This example is based on a room height of 3m
h dif. (m) = Height from occupied zone to ceiling in metres
Vt (m/s) = Velocity in occupied zone in metres per second
Q (l/s) = Air flow Rate in litres per second........... X (m) = Throw in metres (X=B/2)..................................
Q (m3/s) = Air flow rate in metres cubed per second
B = Distance between diffuser axes......................

Symbols:
h dif. (m) = Height from occupied zone to ceiling in metres
Vt (m/s) = Velocity in occupied zone in metres per second
Q (l/s) = Air flow Rate in litres per second........... Throw(m) = Throw in metres ......................................
Q (m3/s) = Air flow rate in metres cubed per second


 
 
 
 
 
 
 
 
 


 
 

 

 
 
 
 

 

 

 

 

 
   
 
 
 
   
   
   
   
   
 
  SCOTTAIRE Davy Way, Llay Industrial Estate, Wrexham,LL12 0PG Tel: 01978 856555 Fax: 01978 856655 Email: sales@scottaire.com