Valve device and multiport regulating assembly comprising a plurality of such devices

A valve device for regulating a gaseous fluid, in a conduit portion, comprising a valve body attached to a support spindle extending transversely into said portion and mounted to rotate therein between open and closure positions, said conduit portion including, on either side of said spindle, opposing internal steps forming two bearing surface portions for corresponding edge parts of said valve body, when said valve body is in the closure position, each step extending substantially over approximately half of the internal circumference of the conduit portion in the region of the mounting position of the support spindle and said steps being offset on either side of the plane perpendicular to the direction of circulation of the fluid in said portion and containing said support spindle such that the pivot angle of the valve body between its maximum open position and its closure position is less than 90°, wherein said valve body has two opposite surface with respective edge parts (6, 6′) are disposed thereon, said edge parts including respective deformable sealing means (7, 7′), for operation thereof in the closure position of said valve body (3), said sealing means defining first and second flexible lips extending from said edge parts (6, 6′) asymmetrically on either side of said valve body (3) and at an inclination to the plane of the valve body (3), the first lip (7) extending outwardly from a corresponding edge of the corresponding edge part (6) toward the exterior and the second lip (7′) extending toward the interior, the first and second lips not contacting the conduit portion except at the steps to minimize friction with the conduit portion as the valve body moves between the open and closure positions.