CPC F16K 1/2261 (2013.01) [F16K 1/222 (2013.01); F16K 1/2263 (2013.01)] | 10 Claims |
1. A butterfly valve comprising: a valve body formed therein with an internal flow passage extending in a direction of a flow passage axis; a seat ring attached to an inner peripheral surface of the internal flow passage; a valve stem supported by the valve body to be rotatable about a rotation axis; a substantially disk-shaped valve element connected to the valve stem to be rotatably supported by the valve body and being placed in the seat ring, said internal passage being closed and opened by rotating the valve element about the rotation axis to bring a peripheral edge portion of the valve element into and out of contact with an inner peripheral surface of the seat ring, wherein
the valve element has an annular outer peripheral edge surface circumferentially extending thereon, and is formed, at opposite positions in the direction of the rotation axis on the outer peripheral edge surface, with two valve stem openings for allowing the valve stem to pass therethrough, said outer peripheral edge surface of the valve element further provided with two annular opening raised portions each protruding from the outer peripheral edge surface and extending along the periphery of the corresponding valve stem opening, and peripheral edge raised portions each protruding from the outer peripheral edge surface and extending in the circumferential direction of the valve element so as to connect between the two opening raised portions, each of said peripheral edge raised portions having a peripheral edge sealing surface that extends along a top thereof to be like an arc in the circumferential direction and flat in the width direction, and chamfered surfaces inclined at a predetermined angle relative to the peripheral edge sealing surface toward the outer peripheral edge surface of the valve element and extending along both sides of the peripheral edge sealing surface,
the seat ring is provided with an outer peripheral surface, an inner peripheral surface, and an annular protrusion protruding from the outer peripheral surface and extending annularly, and the valve body is provided on the inner peripheral surface of the internal flow passage with an annular fitting groove for the annular protrusion of the seat ring to fit therein, and
the annular fitting groove is formed, at opposite positions in the direction of the rotation axis, with two bearing holes for the valve stem to be inserted and be supported therein, and the annular fitting groove includes two opening groove portions provided at the peripheries of the openings of the two bearing holes and two peripheral edge groove portions extending circumferentially so as to connect between the two opening grooves, one of said two peripheral edge groove portions being provided with a chamfered portion at an upper edge portion on a downstream side, the other of said two peripheral edge groove portions being provided with a chamfered portion at an upper edge portion on an upstream side.
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