. Catalog Air flow regulators CONSTANTFLOW EN-EX


Wester_m 14.03.2024


Mechanical rectangular air flow controllers are designed to control supply and extract air flow for constant flow systems, ATEX approved and certified for use in potentially explosive areas

ATEX compliant design
Suitable for gases, air with high humidity and vapors in zones 1 and 2, 21 and 22
For air flow rates up to 12,096 m³/h or 3,360 l/s
The required air flow can be set using the scale on the housing; no additional equipment is required
High control accuracy
No on-site testing required prior to commissioning
Allowable ​air speed​ up to​ 8 m/s
Housing tightness according to EN 1751 class C

Optional equipment

Soundproofing coating to reduce noise generated by the chassis
Additional silencer TX Series to reduce noise generated by air flow

Description of the operating principle
The air flow regulator is a mechanical device that operates without an external power source. The control valve flap with bearings with a low coefficient of friction, under the influence of aerodynamic force, is installed in such a position that, regardless of pressure differences, a constant specified air flow is maintained. Under the influence of the aerodynamic force of the air flow, the damper closes. Under the influence of this force, the inflatable compensator expands and acts as a vibration damper. A leaf spring located behind the cam disc counteracts the closing force of the valve. The cam disk is designed in such a way that when the pressure changes, the damper is adjusted to maintain a constant air flow within small deviations. As a result, the volume of air flow remains constant, with small permissible deviations.

Efficient commissioning
The required air flow is easily and quickly set using the adjustment knob with a pointer; no additional equipment is required. The advantage over flow control dampers is that there is no need for repeated measurements or adjustments during commissioning. If the pressure in the system changes, for example when the control valves open or close, the air flow throughout the system changes. This does not apply to the use of mechanically independent flow regulators. The mechanical regulator reacts immediately and adjusts the valve flap so as to maintain the set constant volume flow.

Standard sizes 200 × 100 – 600 × 600 mm
Air flow range 39 – 3500 l/s or 140 – 12600 m³/h
Air flow control range Approx. from 25 to 100% of nominal flow
Scale accuracy ± 4%
Minimum pressure drop 50 Pa
Maximum pressure drop 1000 Pa
Operating temperature 10 to 50°C


① Damper
② Inflatable compensator
③ Inlet of inflatable compensator
④ Scale sticker
⑤ Potential equalization connection
⑥ Visual display of damper position
⑦ Handle

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