VLV55|VLV65 - Volumetric flow controller
TECHNICAL DOCUMENTATION
Overview of product versions | Function
Construction subject to change
No return possible
Version: 2017-04-24 | Page 3
OVERVIEW OF PRODUCT VERSIONS
VLV55|VLV65 with rubber lip seal
Round volumetric flow controller
Volumetric flow range 0.5-5 m/s (VLV55) or 1-8 m/s (VLV65)
With rubber lip seal (-GD1)
VLV55|VLV65 with flat flange
Round volumetric flow controller
Volumetric flow range 0.5-5 m/s (VLV55) or 1-8 m/s (VLV65)
With flat flange according to DIN 24154, class 5 (-FF1)
VLV55|VLV65 with METU flange
Round volumetric flow controller
Volumetric flow range 0.5-5 m/s (VLV55) or 1-8 m/s (VLV65)
With METU flange type AF, without tension ring (-MF1)
FUNCTION
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).
The housing, measuring nozzle and the controller with pressure
sensor form a closed control loop with feedback, allowing de-
mand-dependent, energy-saving air-conditioning of the single
rooms or areas of air-conditioning systems also at low duct
pressures and air velocities. When suitable controller types are
used, room or duct pressure regulation can be achieved.
For the measurement of the effective pressure, SCHAKO is us-
ing its measuring method by means of a standardised Venturi
nozzle made of aluminium to DIN EN ISO 5167. In front of the
Venturi nozzle and in the nozzle neck, the volumetric flow con-
troller is fitted with openings for pressure take-off. The result-
ing differential pressure (effective pressure) is measured and
evaluated by a universal or compact controller. The VLV meas-
urement principle allows measurement of small volumetric
flows. In comparison with measuring rods, measuring crosses
or measuring orifices having fewer measuring points, this gives
higher accuracy, allowing the inflow area required in front of
the volumetric flow controller to be omitted. This also allows
smaller measurement tolerances to be achieved.
The volumetric flow controllers of the VLV type are insensitive
to dirt caused by dust and can be installed and used inde-
pendently of their position. The mounting instructions docu-
mented by the manufacturer must be adhered to, as otherwise
the correct functioning of the volumetric flow controller is not
guaranteed. The volumetric flow controllers type VLV are not
suitable for air containing sticky and greasy particles (e.g.
kitchen exhaust air).
