A valve device comprising a first and a second channel (3a, 3b) for circulating fluids, which channels may or may not communicate with each other as a function of the position of a movable valve that is mounted between said channels and can move along an axis, said valve device comprising: - a first and a second valve-flap (9a, 9b), one of which belongs to a hollow movable body (11, 18), through which a leak chamber passes, and to which an axial movement is transferred by axial shafts (31, 43, 45) including a central shaft, said first and second valve-flaps (9a, 9b) being designed and mounted to: • prevent communication between said first and second channels in a closed position of said valve; • allow communication between said first and second channels (3a, 3b), about said first and second valve-flaps (9a, 9b), in an open position of said valve; • prevent communication between said first and second channels, whilst allowing communication between only one of said channels and said leak chamber, in two possible cleaning situations; and - a third valve-flap disposed between said first and second valve-flaps, characterised in that: - said third valve-flap does not have a physical link with said central shaft that passes through said valve-flap, so that said third valve-flap can axially move independently of the movement transferred by said shafts (31, 43, 45), - it defines a sealed connection: • with said first valve-flap, in the first cleaning situation, by then coming into abutment against said first valve-flap; and • with said second valve-flap, in the second cleaning situation, by then coming into abutment against said second valve-flap; and, - in the two cleaning situations, two of said valve-flaps (9a, 9b, 9c) are laterally applied against an internal surface of a zone of a fixed external body, said valve being mounted in a mobile manner inside said body. - a first and a second valve-flap (9a, 9b), one of which belongs to a hollow movable body (11, 18), through which a leak chamber passes, and to which an axial movement is transferred by axial shafts (31, 43, 45) including a central shaft, said first and second valve-flaps (9a, 9b) being designed and mounted to: • prevent communication between said first and second channels in a closed position of said valve; • allow communication between said first and second channels (3a, 3b), about said first and second valve-flaps (9a, 9b), in an open position of said valve; • prevent communication between said first and second channels, whilst allowing communication between only one of said channels and said leak chamber, in two possible cleaning situations; and • prevent communication between said first and second channels in a closed position of said valve; • allow communication between said first and second channels (3a, 3b), about said first and second valve-flaps (9a, 9b), in an open position of said valve; • prevent communication between said first and second channels, whilst allowing communication between only one of said channels and said leak chamber, in two possible cleaning situations; and - a third valve-flap disposed between said first and second valve-flaps, - said third valve-flap does not have a physical link with said central shaft that passes through said valve-flap, so that said third valve-flap can axially move independently of the movement transferred by said shafts (31, 43, 45), - it defines a sealed connection: • with said first valve-flap, in the first cleaning situation, by then coming into abutment against said first valve-flap; and • with said second valve-flap, in the second cleaning situation, by then coming into abutment against said second valve-flap; and, • with said first valve-flap, in the first cleaning situation, by then coming into abutment against said first valve-flap; and • with said second valve-flap, in the second cleaning situation, by then coming into abutment against said second valve-flap; and, - in the two cleaning situations, two of said valve-flaps (9a, 9b, 9c) are laterally applied against an internal surface of a zone of a fixed external body, said valve being mounted in a mobile manner inside said body.