METHOD AND AN APPARATUS FOR PREVENTING THE EMISSION OF HARMFUL GASES INTO ATMOSPHERE

An apparatus (100) for conveying leaked gas streams (11,12,13 . . . 1n) leaking at a substantially atmospheric pressure from an industrial plant to a reception body (9) that is pressurised at a predetermined reception pressure (Pr), comprises a collector container (10) of said streams, pneumatically connected with a leaked gas-capturing means, a compressor (20) having a suction mouth (25) pneumatically connected to the collector container (10) and a delivery mouth (26) pneumatically connected to the reception body (9) and to the collector container (10) through a discharge pipe (6) and a recirculating duct (4), respectively. In order to adjust the compressor suction pressure (Ps) at a value below atmospheric pressure (Patm) and above a minimum value of −200÷−100 Pa, the apparatus (100) comprises a control unit (40) in which a control valve (41) is arranged along the recirculation duct (4) and a pressure sensor/transducer (47) is arranged at suction side of compressor (20), the sensor/transducer (47) configured to generate a pressure signal (46) corresponding to the detected suction pressure (Ps), preferably a differential pressure signal (46) between the atmospheric pressure and the compressor pressure suction. Moreover, a pressure controller (45) is configured to receive the suction pressure signal (46), to generate an open/close signal (43) responsive to pressure signal 46, and to transfer the open/close signal (43) to the control valve (41) so as to change its opening according to the detected suction pressure.