| 摘要 |
A flow rate control valve 1 comprises a first sleeve 4 and a second sleeve 5 fitted into an inner periphery of a housing 3 . The both sleeves 4 and 5 have inner end faces 4 d and 5 d which are disposed in abutment against each other while being displaced from each other radially, thereby forming annular stepped end faces 4 d' and 5 d' on a common plane. An edge of the stepped end faces define a first seat S 1 . The valve body 6 has an outer peripheral surface which is formed as a beveled surface, which defines a second seat S 2 . The second seat S 2 of the valve body 6 is disposed in linear contact with the first seat S 1 to close a flow path in a gas passage 2. With this arrangement, a seal leakage when a butterfly valve 7 is closed can be reduced in comparison to the prior art.
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