Fluid flow controlling device

Abstract

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. 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).

I claim: 
     
       1. A fluid flow control device comprising a plurality of .[.pairs of.]. annular discs forming a rigid structure.Iadd., said annular discs including a plurality of cooperating pairs of annular discs, each cooperating pair of .Iaddend.which incorporates a series of substantially radial passageways running from an inner edge to an outer edge of said .Iadd.cooperating pair of .Iaddend.annular discs for fluid flow,   each disc of .[.said.]. .Iadd.each cooperating .Iaddend.pair having .[.two.]. .Iadd.interior and exterior .Iaddend.major faces and .Iadd.partial .Iaddend.passageways which extend completely through said disc between said major faces but extend only partially in a radial direction,   the discs of each .Iadd.cooperating .Iaddend.pair being .[.substantially identical and being.]. aligned with one another with .[.a.]. .Iadd.the interior .Iaddend.major face of one disc in direct abutment with .[.a.]. .Iadd.the interior .Iaddend.major face of the other disc such that the .Iadd.partial .Iaddend.passageways in said one disc interconnect with the .Iadd.partial .Iaddend.passageways in the other disc of the .Iadd.cooperating .Iaddend.pair so as to provide .Iadd.said series of substantially radial passageways .Iaddend.for said fluid flow through the .Iadd.cooperating .Iaddend.pair of .[.substantially identical.]. discs.Iadd.,   the partial passageways of the discs of each cooperating pair open to the exterior major faces thereof being closed by an adjacent disc of said plurality of discs to restrict fluid flow to the series of substantially radial passageways provided by each cooperating pair of discs,   each substantially radial passageway being constructed and arranged to provide a smaller cross-section in a mid-region thereof and a plurality of successive generally right angle turns from one disc to the other between the mid-region to the inner and outer edges of the associated cooperating pair of discs so as to allow alternate bi-directional flow therethrough,   the partial passageways of each disc of cooperating each pair being positioned and configured so that fluid flow from the inner edge to the outer edge of each substantially radial passageway results in an expanding flow through the successive plurality of substantially right angle turns from the mid-region to the outer edge thereof or alternatively fluid flow from the outer edge to the inner edge of each substantially radial passageway results in an expanding flow through the successive plurality of substantially right angle turns from the mid-region to the inner edge thereof.Iaddend.. .[.   
     
     
       2.  A fluid flow control device as claimed in claim 1 comprising a plurality of discs forming a rigid structure which incorporates a series of passageways for fluid flow, the discs having abutting surfaces and passageways therebetween for fluid flow; inlet means formed in said discs to define a predetermined inlet area for conducting fluid to the series of passageways formed by said rigid structure,   outlet means associated with said inlet means to provide a series of openings for exhausting fluid from the passageways,   and wherein at least one of the passageways is of smaller cross-section in a mid-region of its respective discs and increases in cross-section from said mid-region towards the inlet and towards the outlet region of said discs..]..[.3. A fluid flow control device as claimed in claim 2 in which the discs are annular and the passageways increase in cross-section from the mid-region of the annuli towards their inner and outer   
     
     
        peripheries..]. . A fluid flow control device as claimed in claim .[.3.]. .Iadd.1 .Iaddend.in which the discs of .[.the superimposed.]. .Iadd.each cooperating .Iaddend.pair are identical .[.so that.]..Iadd., the partial passageways of .Iaddend.each disc .[.has.]. .Iadd.of each cooperating pair including .Iaddend.at least two different radially-extending series of holes .[.and.]..Iadd., .Iaddend.the discs .[.are.]. .Iadd.of each cooperating pair being .Iaddend.rotated relative to each other so that a first series of holes of one disc is superimposed on a second series of 
     
     
        holes of the other disc and vice versa. 5. A fluid flow control device as claimed in claim .[.2.]. .Iadd.1 .Iaddend.in which the .[.discs are annular and the.]. rigid .[.annular stack so.]. .Iadd.structure .Iaddend.formed .Iadd.by said plurality of discs .Iaddend.is adapted to receive a reciprocating valve plug which is moveable to increase or decrease the number of .[.flow.]. .Iadd.substantially radial .Iaddend.passageways available for fluid flow .Iadd.within said rigid structure.Iaddend.. .[.6. A fluid flow control device as claimed in claim 1 comprising a plurality of discs forming a rigid structure which incorporates a series of passageways for fluid flow, the discs having abutting surfaces and passageways therebetween for fluid flow, and wherein each disc has at least one first passageway formed through the entire thickness of the disc and extending from the outer edge of the disc to end in a mid-region of the disc and at least one second passageway formed through the entire thickness of the disc and extending from the inner edge of the disc to end in a mid-region of the disc, adjacent pairs of discs being oriented so that each first passageway of one disc communicates with a second passageway of the other disc and each second passageway of said one disc communicates with a first passageway of said other disc..]..[.7. A disc suitable for incorporation in a fluid flow control device as claimed in claim 6, the disc having at least one first passageway formed through the entire thickness of the disc and extending from the outer edge of the disc to end in a mid-region of the disc and at least one second passageway formed through the entire thickness of the disc and extending from the inner edge of the disc to end in a mid-region of the disc..]..[.8. A fluid flow control device as claimed in claim 6 in which there are an even number of discs formed in pairs and each pair of discs may provide one or more passageways isolated from the passageways provided by other pairs of discs in the stack..]..[.9. A fluid flow control device according to claim 6, in which each first passageway has a plurality of right angle turns in a plane parallel to the major faces of the discs, the first passageway connects to the second passageway via a turn in the axial direction of the discs and each second passageway has a plurality of right angle turns in a plane parallel to the major faces of   
     
     
        the discs..].10. A fluid flow control device .[.according to.]. .Iadd.as claimed in .Iaddend.claim 1, in which .Iadd.the adjacent disc which closes the partial passageways open to the exterior face of each disc is .Iaddend.a separator disc .[.is positioned between adjacent pairs of identical discs.].. .Iadd.11. A fluid flow control device as claimed in claim 4, in which the first series of holes of each disc includes a central hole of smallest dimension, an inner hole of largest dimension and an outer hole of largest dimension, the second series of holes of each disc including a plurality of intermediate holes of intermediate 
     
     
        dimension. .Iaddend..Iadd.12.  A fluid flow control device comprising a plurality of annular discs forming a rigid structure, said annular discs including a plurality of cooperating pairs of discs,   each cooperating pair of discs providing a series of substantially radial passageways running from an inner edge to an outer edge of said pair of discs for fluid flow,   each disc of each cooperating pair having interior and exterior major faces and partial passageways which extend completely through said disc between said major faces but extend only partially in a radial direction,   the discs of each cooperating pair being aligned with one another with the interior major face of one disc in direct abutment with the interior major face of the other disc such that the partial passageways in said one disc interconnect with the partial passageways in the other disc of the cooperating pair so as to provide the series of substantially radial passageways for said fluid flow through the pair of discs,   the partial passageways of each disc of each cooperating pair being open at the exterior major face thereof with intervening areas of the exterior major face extending therebetween,   said plurality of annular discs providing structure closing the open partial passageways of each disc of each cooperating pair at the exterior major face thereof to restrict fluid flow to the series of substantially radial passageways provided by each cooperating pair,   each substantially radial passageway being provided by an inner partial passageway extending outwardly from the inner edge of one disc of the associated cooperating pair and an outer partial passageway extending inwardly from the outer edge of the other disc of the associated cooperating pair,   the inner and outer partial passageways providing each substantially radial passageway being positioned and configured to terminate in a mid-region of the associated cooperating pair of discs with the terminal ends of each in direct communication so that the fluid flow through each substantially radial passageway as it passes from one partial passageway to the other turns in the directly communicating terminal ends thereof to provide energy loss to the fluid as it flows through said substantially radial passageways thereof,   said cooperating pairs of discs including partial passageways configured to cause substantially right angle turns in the fluid flow as its passes between the edges and terminal ends thereof to thereby provide additional energy loss for the fluid. .Iaddend..Iadd.13. A fluid flow control device as claimed in claim 12 wherein each cooperating pair of discs is made of a carbide or ceramic material. .Iaddend..Iadd.14. A fluid flow control device as claimed in claim 12 in which each inner and outer partial passageway of each substantially radial passageway is configured to cause a plurality of substantially right angle turns in the fluid flow as it passes between the edge and terminal end thereof. .Iaddend..Iadd.15. A fluid flow control device as claimed in claim 14 in which the plurality of substantially right angle turns includes an initial radial to annular turn in one annular direction, an annular to radial turn in the initial radial direction, a radial to annular turn in an opposite annular direction and an annular to radial turn in the initial radial direction. .Iaddend..Iadd.16. A fluid flow control device as claimed in claim 15 in which the discs of each cooperating pair are identical, each disc of each cooperating pair including a series of inner partial passageways and an annularly displaced series of outer partial passageways.   
     
     
        .Iaddend..Iadd.     A fluid flow control device as claimed in claim 16 in which said cooperating pairs of discs are arranged within said rigid structure with the exterior major faces of adjacent pairs of discs in abutting relation, the intervening areas of the abutting exterior major faces of abutting pairs of disc constituting the structure closing the associated partial passageways open to the exterior major faces thereof. .Iaddend..Iadd.18. A fluid flow control device as claimed in claim 16 in which said cooperating pairs of discs are arranged within said rigid structure with separator discs therebetween, said separator discs constituting the structure closing the partial passageways open to the exterior major faces of said cooperating pairs of discs. .Iaddend..Iadd.19. A fluid flow control device as claimed in claim 18 in which the rigid structure formed by said plurality of discs is adapted to receive a reciprocating valve plug which is moveable to increase or decrease the number of substantially radial passageways available for fluid flow within said rigid structure. .Iaddend..Iadd.20. A fluid flow control device as claimed in claim 19 wherein each pair of cooperating discs is made of a carbide or ceramic material, the inner and outer partial passageways providing each substantially radial passageway being defined by carbide or ceramic material surfaces formed by wire EDM or water jet machining. .Iaddend.