ATEX volumetric flow controller VREX

Fields of application

for supply and return air systems
for hazardous areas of zones 1, 2, 21 and 22
also for explosion group llC in zones 1 and 2 (gases)
Control components with ingress protection IP 66
for constant CAV or variable VAV installations
for positive control Vmin, Vmid, Vmax, “OPEN” or “CLOSED”
For volumetric flow and linear pressure control
Measuring range: 0…300 Pa
at ambient temperatures 0 °C…20 °C to +50 °C, requirement: measuring air 0…+50°C/5…95% rH, non-condensing
with command signal 0…10V DC, 2…10V DC,
with supply voltage 24V AC / DC +/- 15%, 50/60Hz
with DD varnish coating for aggressive media
for regulating the air velocity in the duct in the range of 2…13 m/s
can also be used with vertical axis
The round volumetric flow controller type VREX made of galvanised steel is suitable for use with aggressive components of polluted air (only with DD varnish coating or of 1.4301, 1.4571 stainless steel) and in areas subject to explosion hazards. The SCHAKO VREX has been approved for all gases in zone 1, zone 2, as well as for dusts in zones 21 and 22. The SCHAKO VREX can also be used in zones 1 and 2 of the explosion group IIC.


A volumetric flow controller is used for pressure-independent volumetric flow regulation in ventilation and air-conditioning systems. It serves to keep the volumetric flow either constant within specified limits (CAV) or to control it variably (VAV).
Housing, measuring sensor, control flap, PID controller with pressure sensor and actuator form a closed control loop with feedback, allowing demand-dependent, energy-saving air conditioning of single rooms or areas of air-conditioning systems. When suitable electrical controller types are used, room or duct pressure regulation can be achieved.
Since the membrane zero point must not be changed in static sensors, the mounting instructions documented by the manufacturer must be adhered to. The volumetric flow controllers type VREX are not suitable for air containing sticky and greasy particles (e.g. kitchen exhaust air).

Volumetric flow range

53 - 5.794 m³/h