To prevent an increase in a pressure loss at a large opening degree while effectively suppressing cavitation.
A butterfly valve includes, as basic constituent members, a cylindrical valve casing 1 functioning as a part of a flow passage, a valve rod 2 intersecting the flow passage, and a disk-like valve element 3 turning with the valve rod 2 as an axis; and the valve opens and closes the flow passage in the valve casing 1 with turning of the valve element 3. The valve further includes: a porous plate member 7 in a partial sphere shell form, at a downstream side of a part on the orifice side of the valve element 3, to straighten a fluid passing through through-holes 8 of the porous plate member 7 toward the center of the flow passage; and a concave spherical part 10 in a part to be the nozzle side of the valve casing 1. When the valve element 3 is turned, within a range of a predetermined opening degree or smaller, the outer circumference of the part to be the nozzle side of the valve element 3 slides on or approaches the concave spherical part 10, and the flow of a fluid is blocked or suppressed at the nozzle side.
OKADA AKIRA
| JPH0180874U | 1989-05-30 | |||
| JP2006234071A | 2006-09-07 | |||
| JP2003097732A | 2003-04-03 | |||
| JPH0723868U | 1995-05-02 | |||
| JP2003329149A | 2003-11-19 | |||
| JPH051076U | 1993-01-08 | |||
| JPH0180874U | 1989-05-30 | |||
| JP2006234071A | 2006-09-07 | |||
| JP2003097732A | 2003-04-03 |
Higashio Masahiro
Takayoshi Tagawa
Masaji Okamoto