| 摘要 |
<p>A device for driving a double seat valve with two closing elements arranged in series and displaceable with respect to each other. A sleeve-shaped fourth drive piston pressurized by pressure medium, sealingly embraces a second drive piston on the circumference and can engage a catching connection in the direction of a first drive piston, wherein a second drive piston is adapted to be axially displaceable in a limited manner in both directions with respect to the first drive piston and in each case against the force of a second spring.</p> |
