| 摘要 |
A fluid flow control device for use in a variable fluid restrictor control valve or severe service control valve. These valves employ a moveable plug and are used to control high pressure fluids e.g. superheated steam. The control device of the invention includes annular discs with fluid passageways through them. Pairs of discs together form a radial passageway for fluid between the interior of a stack of discs and its radially outer circumference. The passageways may have a smaller cross-section at a mid-region of the disc than at the radially inner or outer side of the disc. +RR The questions raised in reexamination request No. 90/004,962 filed Sep. 29, 1998, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).
|
