| 摘要 |
PURPOSE:To enable the raking-off of deposit adhering to a seat part. CONSTITUTION:A ring like valve seat 2 is fixed to a housing part passing through two spaces la, lb respectively communicating with the upper reaches and lower reaches of a throttle valve. A cylindrical part 12a having an outer diameter D1 smaller than the inner diameter D2 of the valve seat 2 and sealing in a position opposed to the valve seat 2, and a disc like rake-off part 12h axially spaced by the specified distance from the cylindrical part 12a and having an outer diameter D3 larger than the outer diameter D1 of the cylindrical part 12a and smaller than the inner diameter D2 of the valve seat 2 are formed at a valve body 12. This valve body 12 is driven by a driving part into a first position where the cylindrical part 12a is opposed to the valve seat 2, and into a second position where the disc like rake-off part 12h is opposed to the valve seat 2. |
