Type VFC

For low airflow velocities

Circular mechanical self-powered volume flow controllers for the control of supply air or extract air in constant air volume systems with low airflow velocities

  • Suitable for airflow velocities from 0.8 m/s
  • Very simple commissioning
  • Volume flow rate can be set using a rotary knob and a scale on the outside of the casing
  • Simple retrofit of an actuator for variable volume flows
  • Any installation orientation; maintenance-free
  • Casing air leakage to EN 1751, class C


Optional equipment and accessories

  • Secondary silencer Type CA, CS or CF for the reduction of air-regenerated noise
  • Hot water heat exchanger Type WL and electric air heater Type EL for reheating the airflow
  • Actuator for variable volume flows or for Vmin / Vmax switching

CAV controller variant VFC, with rotary knob 00132140_0
  • Application
  • Description

Application

  • Circular CAV controllers of Type VFC for the precise supply air or extract air flow control in constant air volume systems
  • Mechanical self-powered volume flow control without external power supply
  • For low airflow velocities
  • Simplified project handling with orders based on nominal size

Special features

  • Volume flow rate can be set using an external scale; no tools required
  • Simple retrofit of an actuator is possible
  • Correct operation even under unfavourable upstream or downstream conditions (1.5 D straight section required upstream)
  • Any installation orientation
  • Aerodynamic function testing of each unit on a special test rig prior to shipping

Parts and characteristics

  • Ready-to-commission controller
  • Damper blade with low-friction bearings
  • Bellows that acts as an oscillation damper
  • Leaf spring
  • Rotary knob with pointer for setting the volume flow rate
  • Lip seal

Attachments

  • Min/Max actuators: Actuators for switching between minimum and maximum volume flow rate setpoint values
  • Modulating actuators: Actuators for the stepless adjustment of volume flow rates

Useful additions

  • Secondary silencer Type CA, CS or CF
  • Heat exchanger Type WL
  • Electric air heater Type EL

Construction features

  • Circular casing
  • Spigot with lip seal, for circular connecting ducts to EN 1506 or EN 13180
  • Damper blade with low-friction bearings and special bellows

Materials and surfaces

  • Casing made of galvanised sheet steel
  • Damper blade and other parts made of high-quality plastic, to UL 94, V1; to DIN 4102, material classification B2
  • Leaf spring made of stainless steel
  • Polyurethane bellows

Technical information

  • Function
  • Technical data
  • Quick sizing
  • Specification text
  • Order code
Schematic illustration of the VFC 00132975_0

① Damper blade

② Leaf spring

③ Volume flow rate scale

④ Rotary knob locking screw

⑤ Rotary knob

⑥ Lip seal

⑦ Diagram with setting values

⑧ Bellows inlet

Functional description

The volume flow controllers work without an external power supply.

A damper blade with low-friction bearings is adjusted by aerodynamic forces such that a set volume flow rate is maintained within the differential pressure range.

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 maintained almost exactly.

Efficient commissioning

The volume flow rate setpoint value can be set quickly and easily using the pointer on the external scale; no measurements are required.

The advantage over flow adjustment dampers is that there is no need for repeat measurements or adjustments by an air conditioning engineer. Should the system pressure change, e.g. by opening or closing of duct sections, the flow rates in the entire system will also change if flow adjustment dampers are used; however, this is not the case with mechanical self-powered volume flow controllers A mechanical self-powered controller reacts immediately and adjusts the damper blade such that the set constant volume flow rate is maintained.

Nominal sizes80 – 250 mm
Volume flow rate range6 – 370 l/s or 22 – 1332 m³/h
Volume flow rate control rangeApprox. 10 to 100 % of the nominal volume flow rate
Volume flow rate accuracyapprox. ± 10 % of the nominal volume flow rate
Minimum differential pressure30 Pa
Maximum differential pressure500 Pa
Operating temperature10 – 50 °C


Quick sizing: Sound pressure level at differential pressure 50 Pa

Nominal sizeVVAir-regenerated noiseAir-regenerated noiseAir-regenerated noiseAir-regenerated noiseCase-radiated noise
Nominal sizeVV
Nominal sizeVVLPALPA1LPA1LPA1LPA2
Nominal sizel/sm³/hdB(A)dB(A)dB(A)dB(A)dB(A)
80 6 22 25<15<15<15<15
80 10 36 2816<15<15<15
80 20 72 3321<15<15<15
80 42 151 3927181617
100 6 22 2915<15<15<15
100 15 54 3320<15<1515
100 30 108 3726181718
100 65 234 4133262521
125 10 36 22<15<15<15<15
125 20 72 2716<15<15<15
125 45 162 34251816<15
125 100 360 4134292716
160 18 65 2516<15<15<15
160 45 162 3224181618
160 85 306 3629242222
160 185 666 4135302827
200 25 90 2716<15<15<15
200 60 216 312216<1518
200 120 432 3527211922
200 250 900 3730252426
250 37 133 3121<15<1518
250 100 360 3525181622
250 185 666 3628211925
250 370 1332 3729232229

① VFC

② VFC with secondary silencer CS/CF, insulation thickness 50 mm, length 500 mm

③ VFC with secondary silencer CS/CF, insulation thickness 50 mm, length 1000 mm

④ VFC with secondary silencer CS/CF, insulation thickness 50 mm, length 1500 mm


Circular volume flow controllers for constant and variable air volume systems with low airflow velocities, mechanical self-powered, without external power supply, suitable for supply or extract air, available in 6 nominal sizes.

Ready-to-commission unit consists of the casing containing a damper blade with low-friction bearings, bellows, leaf spring, and a rotary knob to set the volume flow rate setpoint.

Differential pressure: 30 – 500 Pa

Volume flow rate: max. 10 : 1

Spigot with lip seal, for circular connecting ducts to EN 1506 or EN 13180.

Casing air leakage to EN 1751, class C.

Special features

  • Volume flow rate can be set using an external scale; no tools required
  • Simple retrofit of an actuator is possible
  • Correct operation even under unfavourable upstream or downstream conditions (1.5 D straight section required upstream)
  • Any installation orientation
  • Aerodynamic function testing of each unit on a special test rig prior to shipping

Materials and surfaces

  • Casing made of galvanised sheet steel
  • Damper blade and other parts made of high-quality plastic, to UL 94, V1; to DIN 4102, material classification B2
  • Leaf spring made of stainless steel
  • Polyurethane bellows

Technical data

  • Nominal sizes: 80 to 250 mm
  • Volume flow rate range: 6 to 370 l/s or 22 to 1332 m³/h
  • Volume flow rate control range: approx. 10 – 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: 500 Pa

00131326_0

 Type
VFC       Volume flow controller

 

 Nominal size [mm]
80
100
125
160
200
250

 Actuator
       No entry: manual operation
       For example
E01       24 V AC/DC, 3-point, potentiometer
E03       24 V AC/DC, modulating 2 – 10 V DC, potentiometer
M01       24 V AC/DC, 3-point, mechanical stops

 

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For general question regarding products or services you can also call:
Tel.: +7 495 221-5161 | Fax: +7 495 221-5171