Type VFL

Volume flow limiter for insertion into ducting

Circular, mechanical self-powered controllers for insertion into ducting, for the quick and easy balancing of constant volume flow rates in ventilation and air conditioning systems

  • Unique damper blade edge for acoustic optimisation
  • Simple and quick commissioning on site
  • Range of volume flow rate setpoints for each nominal size
  • Precise and simple setting of volume flow rates using a scale
  • Best accuracy among controllers for insertion
  • Suitable for low airflow velocities from 0.8 m/s
  • Any installation orientation; maintenance-free

Volume flow limiter Type VFL 00134342_0


  • Application
  • Description

Application

  • Circular volume flow limiters of Type VFL for the simple balancing of volume flow rates in air conditioning systems
  • Mechanical self-powered volume flow limiter without external power supply
  • Simplified project handling with orders based on nominal size
  • Set the required volume flow rate using a scale

Special features

  • Mechanical self-powered
  • Low-friction bellows
  • For circular ducts
  • Lip seal for tight and secure fit
  • Aerodynamically tested and factory set to a reference volume flow rate
  • Sticker showing volume flow rates (in l/s, m³/h and cfm) that can be set each limiter

Nominal sizes

  • 80, 100, 125, 150, 160, 200, 250

Parts and characteristics

  • Ready-to-commission limiter
  • Damper blade with low-friction bearings
  • Bellows that acts as an oscillation damper
  • Leaf spring
  • Lip seal
  • Multi-level volume flow rate setpoint values

Construction features

  • Circular casing
  • Suitable for insertion into circular ducts to EN 1506 or EN 13180
  • Lip seal for tight and secure fit
  • Acoustically optimised damper blade with low-friction bearings and special bellows
  • Different damper blade construction and volume flow rate sticker for nominal size 150

Materials and surfaces

  • Casing and damper blade made of high-quality plastic, to UL 94, V0; to DIN 4102, material classification B2
  • Leaf spring made of stainless steel
  • Polyurethane bellows

Standards and guidelines

  • Hygiene conforms to VDI 6022

Maintenance

  • Maintenance-free as construction and materials are not subject to wear

Technical information

Function, Technical data, Quick sizing, Specification text, Order code, Produktbeziehungen

  • Function
  • Technical data
  • Quick sizing
  • Specification text
  • Order code
Schematic illustration of the VFL 00119710_0..
① Damper blade
② Bellows inlet
③ Bellows
④ Crossbar
⑤ Volume flow rate scale


Functional description

The volume flow limiter is a mechanical self-powered unit and works without external power supply. A damper blade with low-friction bearings is adjusted by aerodynamic forces such that the set volume flow rate is limited as a consequence.

The aerodynamic forces of the airflow create a closing torque on the damper blade. The bellows extends and increases this force while at the same time acting as an oscillation damper. The closing force is countered by a leaf spring. As the differential pressure changes, the leaf spring adjusts the position of the damper blade such that the volume flow rate is limited.

Efficient commissioning

The volume flow limiter performs the previously tedious and expensive balancing of volume flow rates in ventilation and air conditioning systems.

Simple handling and perfect function help to save valuable working time on site. The required volume flow rate can be set at the point of installation, then the volume flow limiter is inserted into the duct. The set volume flow rate will then be limited and maintained within close tolerances.

Volume flow rate ranges

The volume flow limiters are factory set to the reference volume flow rate Vref. Customers can then simply set the required volume flow rate (setting values 1 to 11).

Nominal size
1
V
m³/h
2
V
m³/h
3
V
m³/h
4
V
m³/h
5
V
m³/h
6
V
m³/h
7
V
m³/h
8
V
m³/h
9
V
m³/h
10
V
m³/h
11
V
m³/h
VNenn
m³/h
Vref
m³/h
80 14 17 22 28 33 39 50 62 73 82 82 33
100 18 24 33 39 48 58 71 79 92 105 122 122 71
125 39 48 58 69 82 98 113 131 150 171 195 195 98
150 50 70 85 105 120 140 160 185 205 230 265 265 160
160 58 82 102 128 156 175 195 217 242 272 323 323 156
200 94 127 166 207 253 297 343 391 436 481 529 529 297
250 159 215 278 337 399 473 519 574 632 705 764 764 473


Nominal size
1
V
l/s
2
V
l/s
3
V
l/s
4
V
l/s
5
V
l/s
6
V
l/s
7
V
l/s
8
V
l/s
9
V
l/s
10
V
l/s
11
V
l/s
VNenn
l/s
Vref
l/s
80 4 5 6 8 9 11 14 17 20 23 23 9
100 5 7 9 11 13 16 20 22 26 29 34 34 20
125 11 13 16 19 23 27 31 37 42 48 54 54 27
150 14 19 24 29 33 39 44 51 57 64 74 74 44
160 16 23 28 36 43 49 54 60 67 76 90 90 43
200 26 35 46 58 70 83 95 109 121 134 147 147 83
250 44 60 77 94 111 131 144 160 175 196 212 212 131


Nominal sizes

80 – 250 mm

Volume flow rate range

4 – 212 l/s or 14 – 764 m³/h

Volume flow rate control range

< 20 – 100 % of the nominal volume flow rate

Volume flow rate accuracy

approx. ± 10 % of the nominal volume flow rate

Minimum differential pressure

30 Pa

Maximum differential pressure

300 Pa

Operating temperature

10 – 50 °C




Quick sizing tables provide a good overview of the room sound pressure levels that can be expected. Approximate intermediate values can be interpolated. Precise intermediate values and spectral data can be calculated with our Easy Product Finder design programme.

The first selection criteria for the nominal size are the actual volume flow rates Vmin and Vmax. The quick sizing tables are based on generally accepted attenuation levels. If the sound pressure level exceeds the required level, a larger air terminal unit and/or a silencer is required.

VFL, Sound pressure level at differential pressure 50 Pa

Nominal size V Air-regenerated noise
Nominal size V LPA
Nominal size l/s m³/h dB (A)

80

4

14

30

80

6

22

30

80

14

50

32

80

20

73

33

80

23

82

34

100

5

18

31

100

11

39

33

100

16

58

35

100

26

92

36

100

34

122

37

125

11

39

36

125

19

69

37

125

27

98

37

125

42

150

38

125

54

195

39

150

14

50

32

150

29

105

32

150

44

160

33

150

57

205

33

150

74

265

34

160

16

58

26

160

28

102

29

160

49

175

32

160

67

242

34

160

90

323

36

200

26

94

23

200

70

253

27

200

109

391

30

200

134

481

31

200

147

529

31

250

44

159

23

250

94

337

26

250

144

519

28

250

175

632

28

250

212

764

28


Circular volume flow limiters in 7 nominal sizes, made of high-quality plastic, to limit and control volume flows in air conditioning systems.

Ready-to-commission unit which consists of the casing with setpoint scale and the control mechanism with leaf spring and low-friction, silicone-free bellows.

Easy insertion into circular ducts to EN 1506 or EN 13180; secure fit ensured by a lip seal.

Aerodynamically tested and factory set to a reference volume flow rate. Can be subsequently accurately adjusted within a volume flow rate range of at least 5 : 1.

Special features

  • Mechanical self-powered
  • Low-friction bellows
  • For circular ducts
  • Lip seal for tight and secure fit
  • Aerodynamically tested and factory set to a reference volume flow rate
  • Sticker showing volume flow rates (in l/s, m³/h and cfm) that can be set each limiter

Materials and surfaces

  • Casing and damper blade made of high-quality plastic, to UL 94, V0; to DIN 4102, material classification B2
  • Leaf spring made of stainless steel
  • Polyurethane bellows

Technical data

  • Nominal sizes: 80 – 250 mm
  • Volume flow rate range: 4 to 212 l/s or 14 to 764 m³/h
  • Volume flow rate control range: < 20 to 100 % of the nominal volume flow rate
  • Volume flow rate accuracy: approx. ± 10 % of the nominal volume flow rate
  • Minimum differential pressure: 30 Pa
  • Maximum differential pressure: 300 Pa

Sizing data

  • V _______________________ [m³/h]
  • Δpst _______________________ [Pa]

Air-regenerated noise

  • LPA _______________________ [dB(A)]

00132648_0

 Type
VFL       Volume flow limiter

 

 Nominal size [mm]
80
100
125
150
160
200
250

Order example: VFL/100

Nominal size

100 mm


 

Dimensions and weight, Product details

  • Dimensions and weight
  • Product details
VFL 00131010_0


Nominal size
ØD
mm
L
mm
m
kg
80 78 86 0.10
100 98 100 0.15
125 122 118 0.25
160 156 148 0.40
200 196 175 0.50
250 246 220 0.70



Installation details, Basic information and nomenclature

  • Installation details
  • Basic information and nomenclature

Installation and commissioning

  • Any installation orientation
  • Set the required volume flow rate using a scale
  • Insert the unit into the duct
  • Mark the installation location

Upstream conditions

The volume flow rate accuracy ΔV applies to a straight upstream section of the duct. Bends, junctions or a narrowing or widening of the duct cause turbulence that may affect measurement. Duct connections, e.g. branches off the main duct, must comply with EN 1505. Some installation situations require straight duct sections upstream.

Free air intake only with a straight duct section of 1D upstream.

Space required for commissioning and maintenance

Sufficient space must be kept clear near any attachments to allow for commissioning and maintenance. It may be necessary to provide sufficiently sized inspection access openings.

Prinipal dimensions

ØD [mm]

Outside diameter of the spigot

ØD₁ [mm]

Pitch circle diameter of flanges

ØD₂ [mm]

Outside diameter of flanges

ØD₄ [mm]

Inside diameter of the screw holes of flanges

L [mm]

Length of unit including connecting spigot

L₁ [mm]

Length of casing or acoustic cladding

B [mm]

Duct width

B₁ [mm]

Screw hole pitch of flange (horizontal)

B₂ [mm]

Outside dimension of flange (width)

B₃ [mm]

Width of device

H [mm]

Duct height

H₁ [mm]

Screw hole pitch of flange (vertical)

H₂ [mm]

Outside dimension of flange (height)

H₃ [mm]

Unit height

n [ ]

Number of flange screw holes

T [mm]

Flange thickness

m [kg]

Unit weight including the minimum required attachments for manual adjustment

Acoustic data

fm [Hz]

Octave band centre frequency

LPA [dB(A)]

A-weighted sound pressure level of air-regenerated noise of the VAV terminal unit, system attenuation taken into account

LPA1 [dB(A)]

A-weighted sound pressure level of air-regenerated noise of the VAV terminal unit with secondary silencer, system attenuation taken into account

LPA2 [dB(A)]

A-weighted sound pressure level of case-regenerated noise of the VAV terminal unit, system attenuation taken into account

LPA3 [dB(A)]

A-weighted sound pressure level of case-regenerated noise of the VAV terminal unit with acoustic cladding, system attenuation taken into account


All sound pressure levels are based on 20 μPa.

Volume flow rates

Vnom [m³/h] and [l/s]

Nominal volume flow rate (100 %)

  • The value depends on product type and nominal size
  • Values are published on the internet and in technical leaflets, and stored in the Easy Product Finder design software.
  • Upper limit of the setting range and maximum volume flow rate setpoint value for the CAV controller

V [m³/h] and [l/s]

Volume flow rate

ΔV [± %]

Volume flow rate tolerance from setpoint value

Differential pressure

Δpst [Pa]

Static differential pressure

Δpst min [Pa]

Static differential pressure, minimum

  • The static minimum differential pressure is equal to the pressure loss of the CAV controller when the damper blade is open, caused by flow resistance (bellows, crossbar)
  • If the pressure on the CAV controller is too low, the setpoint volume flow rate may not be achieved, not even when the damper blade is open
  • Important factor in designing the ductwork and in rating the fan including speed control
  • Sufficient duct pressure must be ensured for all operating conditions and for all controllers, and the measurement point or points for speed control must have been selected accordingly to achieve this

Construction

Galvanised sheet steel

  • Casing made of galvanised sheet steel
  • Parts in contact with the airflow as described for the product type
  • External parts, e.g. mounting brackets or covers, are usually made of galvanised sheet steel

Powder-coated surface (P1)

  • Casing made of galvanised sheet steel, powder-coated RAL 7001, silver grey
  • Parts in contact with the airflow are powder-coated or made of plastic
  • Due to production, some parts that come into contact with the airflow may be stainless steel or aluminium, powder-coated
  • External parts, e.g. mounting brackets or covers, are usually made of galvanised sheet steel

Stainless steel (A2)

  • Casing made of stainless steel 1.4201
  • Parts in contact with the airflow are powder-coated or made of stainless steel
  • External parts, e.g. mounting brackets or covers, are usually made of galvanised sheet steel

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Visual contact Visual contact

Your message is send and will be processed shortly.
Our department for Service-Requests will contact you asap.
For general question regarding products or services you can also call:
Tel.: +60 6 678 8188 | Fax: +60 6 678 8288 (388)