| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a butterfly valve that reduces unbalance of pressure in both flow passages on an orifice side and a nozzle side even immediately after the start of opening a valve, while preventing large resistance in an orifice when valve opening becomes considerably large or causing adhesion of dust or natural objects, and prevents damage, etc. to the valve due to the unbalance. <P>SOLUTION: This butterfly valve includes a valve element 1 to be mounted on a valve rod 3, and a seat ring 9 to be fixed to an inner periphery of a conduit. A resistor 11 projecting toward an upstream side of the conduit and having a predetermined radius from a rotation axial center of the valve rod 3 as seen from a cross sectional surface direction of the conduit, is mounted at a nozzle side end part 1b of the valve element 1. A distal end surface 11x of the resistor 11 is formed to face the seat ring 9 via a predetermined gap G with respect to the seat ring 9 when the valve element 1 is rotated. <P>COPYRIGHT: (C)2012,JPO&INPIT |
