| 摘要 |
The present invention relates to a pressure control means for controlling the pressure within a tubular chamber containing a flowing fluid and adapted to discharge the flowing fluid from the downstream end thereof, including a diverging seat formed in the opening of the downstream end of the tubular chamber, a cone shaped plug slideably mounted adjacent the opening and having a contour adapted to prevent cavitation of the fluids being discharged from the tubular chamber and to form an annular opening between the plug and the diverging seat, a piston chamber mounted adjacent and spaced from the plug, a piston mounted in the piston chamber, shorter than the length of the piston chamber and essentially equal in cross section to the cross section of the chamber, slideably mounted in the chamber and in fluid-tight relation with the inner wall of the chamber to thus vary the void space within the chamber adjacent the ends of the piston and, including, a plurality of disc-type segments detachably coupled together to form the piston and having a reduced diameter shoulder formed on one end of each of the disc-type segments to form an annular channel between adjacent ones of the disc-type segments when the segments are coupled together and a sealing ring in the annular channel to produce the fluid-tight relation between the piston and the inner wall of the piston chamber, the plug being coupled to the piston to slide with the piston and an operating fluid introduction means adapted to introduce a pres |
