| 摘要 |
PROBLEM TO BE SOLVED: To prevent a reverse flow of gas from an exhaust side to a suction side by improving the responsiveness of a differential pressure type vacuum valve, especially responsiveness in closing a valve. SOLUTION: This valve comprises a valve housing 34 put in a middle of an exhaust gas passage 33, a valve function body 40 slidably stored in the valve housing and abutting on and separating from a valve seat 38 to open and close the exhaust gas passage 33, a valve chamber 51 defined at one side of a partition 43 formed in the valve function body, a spring member 52 installed in the spring chamber, an atmospheric pressure chamber 50 defined at the other side of the partition 43 and communicating with the atmosphere via a through hole 47 formed at the valve housing wall, and communication paths 53-55 capable of connecting the spring chamber 51 selectively to an outlet side exhaust path 36 of the valve function body 40 or the atmospheric pressure chamber 50. A quantity of atmospheric air flowing in a spring chamber 51 is kept larger as compared to a quantity of atmospheric air flowing in the through hole 47 by opening and closing the exhaust gas passage by selectively being connected to the outlet side exhaust path 36 or the atmospheric pressure chamber 50. COPYRIGHT: (C)2009,JPO&INPIT
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