RVT-R-EX VAV round variable flow regulator made of plastic, anti-explosion version
Specification
VAV regulator operating from the flow rate of 1 m/s, equipped with an actuator and Venturi tube. Made of PPS, suitable for use in aggressive environment for explosion hazard zones (EX).
Intended use
VAV regulators are used for the automatic control of airflow volume in the ventilation installations where aggressive chemical compounds may occur. RVT-R-Ex devices ensure high safety level and are intended for locations where explosive atmospheres are likely to occur. RVT-R-Ex regulators are designed in accordance with ATEX 2014/34/EC as devices from group II category 2 intended for use in explosion hazard zones 1, 2, 21 and 22. The manufacturer’s ATEX Certificate is available for electric components.
Performance
Housing, measuring element and regulation damper shutter are made of thermoplastic, nonconductive polypropylene PPs-el with resistance lower than 105 Ohm. This regulator, according to PNEN1751, has the air leakage B1 (for Dn125 mm) or B2 (for Dn160-500 mm).
Operation principle
The control-drive system of the flow regulator is an integrated control-drive unit or an assembly consisting of a differential pressure static sensor, PID digital regulator and actuator. The operating rule is based on the measurement of the air stream flowing through the regulator. In RVT-R-Ex regulators, Venturi tube is used as an accumulating-measuring element, according to DIN EN ISO 5167-1, what guarantees a high precision level of measurement. Stab pipes for pressure measurement are placed on its both sides.
During the air flowing through the measuring element, on its both sides, pressure difference is generated depending on the flow stream. The signal from accumulating elements is transmitted to the pressure sensor by means of flexible impulse tubes. A pressure value on the accumulating element is transmitted to the regulator in which it is converted to the flow value and compared with the set value. If the measured value differs from the set value, the regulation shutter actuator sets it to the position excluding the difference between the measured value and the set value.
