VENTILISATION WITH WHICH CONTRACTED RADIO IS PLANNED

摘要

A valve seat ring (300) includes an upper convex arc-shaped transition to improve flow flow flow and a valve seat surface (318) to slow down valve retraction. The valve seat surface (318) contains a radial convex arc-shaped segment (322),defining an external curvature radius, which forms a first wear crown (324) for contact with the valve (118, 120, 218, 220) in an early wear condition, a radial inner convex arc-shaped segment (326),defining an internal curvature radius, forming a second wear crown (328) to touch the valve (118, 120, 218, 220) in a later wear condition, and a linear segment (330),which extends between the radial outer convex arc-shaped segment (322) and the radial inner convex arc-shaped segment (326).