VENTILISATION WITH WHICH CONTRACTED RADIO IS PLANNED

摘要

A valve seat ring (400) includes an upper convex arc-shaped transition (420) to improve flow flow and a valve seat surface (418) to slow down the valve retraction. The valve seat surface (418) contains a radial convex arc-shaped segment (422),defining an external curvature radius, which forms a first wear crown (424) for contact with the valve (120) in an early wear state, a radial inner convex arc-shaped segment (426, 426a, 426b),defining an internal curvature radius, forming a second crown of wear (428) to touch the valve (120) in a later state of wear, and a linear segment (430),which extends between the radial outer convex arc-shaped segment (422) and the radial inner convex arc-shaped segment (426, 426a, 426b).