Active Control

All volume flow controllers on the market use the differential pressure via a flow resistor to measure the volume flow, be it a measuring cross or an orifice plate. The accuracy of the velocity measurement of volume flow controllers is limited by the level of the measurable pressure signal. Since the reliable control of small volume flows will be an important aspect for future building concepts, LTG has developed a measuring method that automatically improves the measuring accuracy, especially for small air volumes.

Unlike conventional measuring methods, the differential pressure is not measured at an upstream element such as an orifice plate or a measuring cross. With the VRactive series volume flow controllers, the differential pressure is measured directly in the area of the damper blade. Although the largest disturbance of the velocity field is present here, it also has the largest measurement signal due to locally accelerated air flow. The volume flow can now be determined with great accuracy, but is a function of the damper angle and pressure difference at the measuring element – mapped in a mathematical multidimensional map.

This system achieves the highest control accuracy of all known systems in the low air velocity range. As the map control does not use a large obstruction to increase the pressure signal (as is the case with the orifice), the VRactive controllers have an extremely low pressure loss and further contribute to the energy efficiency of the ventilation system.

The LTG volume flow controllers are available with both dynamic and static measuring methods (VRactive-s). Products with the ActiveControl system:VREactive, VRFactive and VRDactive.