| 摘要 |
<p>PURPOSE: To incorporate a bypass valve in a slide valve provided in the duct of a vacuum device by forming hollow portions on both sides of a valve element, and placing a piston having a projection that cooperates with the inclined path of a drive rod, in such a way that a sealing means is interposed between the piston and the shoulder of each hollow portion and that the piston is spring- activated in a returning direction. CONSTITUTION: A valve body 1 penetrated by the drive rod 2 of a control actuator is formed with openings 12, 13 and a valve element 10 is attached to the drive rod 2 and allowed to freely slide within the valve body 1. Hollow portions 17 are formed on both sides of the valve element 10 and opened to both sides to store a piston 18. A flat gasket 21 is interposed between the piston 18 and the shoulder 20 of each hollow part 17 to seal a communicating orifice 22. A return spring 23 is also interposed between the piston 18 and the shoulder 20 to press the piston 18 against a simple abutment 19 at a stop position. Also, a projection 24 is formed on the side of the piston 18 opposite to the drive rod 2, and when the valve is closed the projection 24 is made to abut against the inclined path 26 of the drive rod 2 to push the valve element 10 back.</p> |
