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TROX VFC round low air flow constant volume regulator
TROX VFC constant volume regulator for circular duct systems
TROX VFC low airflow regulator side view
TROX VFC round constant volume flow controller detail
TROX VFC circular airflow regulator product image

TROX VFC – Round Low Air Flow Constant Volume Regulator

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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 157.5 fpm
  • 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 COptional equipment and accessories
  • Circular silencer CA (for Germany and Switzerland), CAH (for EMEA) or CF for the reduction of air-regenerated noise
  • Hot water heat exchanger WL and electric air heater EL for reheating the airflow
  • Actuator for variable volume flows or for qᵥmin-qᵥmaxswitching
E:Mail: sales@walkair.us to confirm availability or for volume discounts
SKU: VFC Category: Tag:

General Information

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 characteristics
  • The volume flow rate can be set using an external scale; no tools required
  • Simple retrofitting of an actuator
  • Correct operation even under unfavourable upstream or downstream conditions (1.5 D straight section required upstream)
  • Any installation orientation
  • Aerodynamic functional testing of each unit on a special test rig before shipping

 

Nominal sizes
  • 3, 4, 5, 6, 8, 10

 

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 varying volume flow rates

 

Useful additions
  • Circular silencers CA (for Germany and Switzerland) and CAH (for EMEA)
  • Heat exchanger WL
  • Electric air heater EL
  • Useful additions have to be ordered separately

 

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, fire rating class B2
  • Leaf spring made of stainless steel
  • Polyurethane bellows

 

Standards and guidelines
  • Meets the hygiene requirements of VDI 6022
  • Casing air leakage to EN 1751, class C

 

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

 

Disclosure of Chemicals

  • RoHS EU Directive 2011/65/EU (RoHS)
    • This product or single variants comply with EU Directive 2011/65/EU (RoHS) on the restriction of the use of certain hazardous substances in electrical and electronic equipment. For more information, please refer to our Environmental Product Declarations
  • REACH 1907/2006 (EC Regulation REACH)
    • This product or single variants comply with the provisions of EC Regulation No. 1907/2006, also known as REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals). For more information, please refer to our Environmental Product Declarations

Function

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.

 

Schematic illustration of the VFC

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

Specification Text

This specification text describes the general properties of the product. Texts for variants can be generated with our Easy Product Finder design program.
Circular volume flow controllers for constant and variable air volume systems with low airflow velocities, mechanical selfpowered, 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: 0.12 – 2.01 in WG
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 characteristics
  • The volume flow rate can be set using an external scale; no tools required
  • Simple retrofitting of an actuator
  • Correct operation even under unfavourable upstream or downstream conditions (1.5 D straight section required upstream)
  • Any installation orientation
  • Aerodynamic functional testing of each unit on a special test rig before 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, fire rating class B2
  • Leaf spring made of stainless steel
  • Polyurethane bellows

 

Technical data
  • Nominal sizes: 3″ – 10″
  • Volume flow rate range: 13 – 784 cfm
  • 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: 0.12 in WG
  • Maximum differential pressure: 2.01 in WG

Downloads

Retrofit Kits Product Data Sheet

VFC Product Data Sheet

VFC Declaration of Conformity or Declaration of Incorporation

VFC Declaration of Conformity or Declaration of Incorporation 2

VFC Declaration of Hygiene Conformity

VFC Manufacturer’s Statement Concerning Statistical Leakage Tests

VFC Operating Manual

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