FLAP VALVE DEVICE AND GAS-LIQUID SEPARATING DEVICE COMPRISING FLAP VALVE DEVICE

Provided is a flap valve device and a gas liquid separation device provided with a flap valve wherein the flap valve device is highly compact, and is easy to assemble. In a normally open flap valve device (2) comprising a main body (5) having an opening (4), a flap (6) for selectively closing the opening and a torsion coil spring (7) provided between the main body and the flap for biasing the flap in an opening direction, the flap valve device further comprises a main body side bearing (21) provided on the main body; a flap side bearing (25) provided on the flap; a connecting member (27) including a hinge shaft (27A) passed through the main body side bearing, the flap side bearing and a coil portion (7A) of the torsion coil spring so as to serve as a pivot shaft for the flap, and an extension (27B) extending from an end of the hinge shaft along an outer part (6B) of the flap; and a spring engagement portion (43) provided on the main body for engaging an end of the torsion coil spring; another end of the torsion coil spring being engaged by the extension, the extension being engaged on the outer part of the flap.