| 摘要 |
<p>VALVE WITH ACTUATOR A valve with actuator is disclosed with the valve controlled by a piston responsive to in line fluid pressure during opening and closing movement. The actuator shifts a valve stem to open a poppet valve in the piston to admit in line pressure into a chamber to act on rearward surfaces of the piston to advance the piston for valve closing. Closing movement of the piston is started by the actuator and continued by in line fluid pressure. A valve on the stem controls communication of the chamber, in which the piston is carried, with an outlet to close the chamber for pressurization effect causing forward seating of the piston. Valve opening movement of the actuator closes the piston mounted poppet valve and vents the chamber allowing in line fluid pressure to shift the piston rearwardly to an open position. Another form of the valve with actuator includes a housing defining lengthwise passageways communicating an inlet with an outlet.</p> |
