Butterfly valve with metal seat ring and flap - has taper face on flap disc bearing against arched face on seat ring

摘要

The butterfly valve has a metal seat ring fixed to the housing wall and a metal flap disc swinging about an axis clear of the plane of the ring and bearing by its edge against a taper face on the ring when shut. This ring seat face is arched, while that on the disc is tapered so as to give line contact along a circle between them, whose plane is at right angles to the axis of the taper face. The latter is enclosed between two parallel planes intersecting the plane of the circle at a small angle.