JPS5510110A - Butterfly valve - Google Patents

Abstract

PURPOSE: To prevent the bent portion of a butterfly valve from cracking by providing an elastic seat ring integrally with the hollow cylindrical valve body of the valve reducing the central portion of the seat ring, and increasing both the sides of the seat ring in thickness to thereby increase the strength of the seat ring.

CONSTITUTION: The valve body 1 of a butterfly valve is elevationally inwardly projected at the inner peripheral surface thereof in circular arc 22-21-23 from the portion 21 in cross section at the position facing with the peripheral edge of a valve plate 4 upon closure of the valve plate 4. The seat ring 20 making contact with the valve body 1 is correspondingly recessed at the outer peripheral surface thereof in circular arc, and radially outwardly bent at both the ends thereof to engage in mesh with the annular grooves 14 extending in central direction of the valve body 1 formed at the side surfaces of the valve body 1. Since the angle β formed between the surface making contact with the inner peripheral surface of the valve 1 and the inner surface of the bent portion making contact with the side surface of the seat ring 20 is obtuse, it can prevent the inner surface of the bent portion of the seat ring 20 from cracking.

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