Abstract:
A valve uniquely integrates ball valve and throttling valve principals, thus affording quieter stop-and-start operation. A ball held by two seat rings is rotatable ninety degrees and has a diametric bore adjustable between fully closed (0°) and fully open (90°) positions. Oppositely disposed, relative to both the ball and the valve&#39;s longitudinal axis, are two plate assemblies each describing a tortuous fluid path. Each ring has conduits communicating with an assembly&#39;s tortuous path and communicable with the bore so that, sequentially during the ball&#39;s 0° to 90° rotation: the ball seals off the conduits, no fluid passing through the valve; all fluid passing through the valve flows through the plate assemblies and conduits; some fluid passing through the valve flows through the plate assemblies and conduits, some fluid passing through the valve flowing freely; the ball seals off the conduits, all fluid passing through the valve flowing freely.

Description:
STATEMENT OF GOVERNMENT INTEREST 
   The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to methods and apparatuses for controlling or regulating the flow of fluids, more particularly to valves for stopping and starting fluid flow, such as ball valves. 
   Valves are devices that are used for controlling the flow of fluid. There are several categories of valves, such as stop valves, check valves, pressure-control valves and thermostatic recirculating valves. Of particular interest herein are stop valves, which are used to partially or completely shut off fluid flow, and which generally involve fluid control via movement of a valve member such as a valve stem. Among the various types of stop valves are ball valves, globe valves, gate valves, plug valves, needle valves and butterfly valves. 
   Ball valves are stop valves according to which a ball having a hole (e.g., axial bore) provided therethrough is used for stopping or starting fluid flow. To open the ball valve, the ball is rotated to a position wherein the ball&#39;s hole is aligned with both the inlet and the outlet of the valve body. To close the ball valve, the ball is rotated to a position wherein the hole is perpendicular to both the inlet and the outlet of the valve body. Frequently, a valve handle or planetary gearing is used to effect a ninety degree turn, either for rotating the ball from a closed position to an open position or, conversely, for rotating the ball from an open position to a closed position. Ball valves have been used in fluid systems that require a high-pressure drop across the valve when opening. 
   Ball valves are excellent for most piping systems, as they provide minimal restriction to flow when fully open and a positive stop when closed. When the ball valve is opened with a high pressure on one side and a low pressure on the other side, a noise is generated during opening. As the ball rotates, it exposes a small flow passage area that gradually increases with continued rotation. The noise that is generated in the short time during which the opening takes place is significantly greater relative to the steady state flow noise that occurs after the ball valve is fully open. Thus, unwanted noise is associated with the opening of a ball valve under such circumstances wherein a high-pressure source exists on one side of the ball valve and the fluid leads to a low-pressure region on the opposite side of the ball valve. 
   Nor do quiet throttling valves provide a satisfactory solution to the above-described noise difficulty characterizing piping systems. Throttling valves typically are characterized by fluid path tortuosity. For instance, according to current technology of quiet throttling valves used at the Naval Surface Warfare Center, Carderock Division (NSWCCD), the fluid flow is opened to a tortuous path of a series of orifices on multiple disk stacks. This tortuous path reduces flow noise associated with fluid cavitation, which occurs as a result of a large pressure drop, by dividing up the pressure drop into a series of small pressure drops. Flow path in the quiet throttling valve is always through the disk stacks. This is undesirable in shipboard fluid systems since, in comparison with a full-open ball valve, there is a significant increase in (i) the time required to move a fluid from one location to another and (ii) the restriction in the system. 
   Incorporated herein by reference are the following United States patents relating to valve technology: Ryerson et al. U.S. Pat. No. 6,408,871 B1 issued Jun. 25, 2002; Baumann U.S. Pat. No. 6,244,297 B1 issued Jun. 12, 2001; Tuttle U.S. Pat. No. 6,109,591 issued Aug. 29, 2000; McCarty et al. U.S. Pat. No. 6,095,196 issued Aug. 1, 2000; Wears et al. U.S. Pat. No. 6,026,859 issued Feb. 22, 2000; Baumann et al. U.S. Pat. No. 5,941,281 issued Aug. 24, 1999; Knop et al. U.S. Pat. No. 5,921,275 issued Jul. 13, 1999; Lebo et al. U.S. Pat. No. 5,819,803 issued Oct. 13, 1998; Baumann et al. 5,769,122 issued Jun. 23, 1998; Greer U.S. Pat. No. 5,370,154 issued Dec. 6, 1994; Vick U.S. Pat. No. 4,458,718 issued Jul. 10, 1984; Seger U.S. Pat. No. 4,279,274 issued Jul. 21, 1981; Vick U.S. Pat. No. 3,978,891 issued Sep. 7, 1976; Hayner et al. U.S. Pat. No. 3,688,800 issued Sep. 5, 1972. 
   SUMMARY OF THE INVENTION 
   In view of the foregoing, it is an object of the present invention to provide a quieter methodology for effecting stop-and-start fluidic valvular function. 
   It is another object of the present invention to provide such a methodology wherein full fluid flow is allowed without restriction to that flow. 
   In accordance with many embodiments of the present invention, a fluid valve device has on opposite sides thereof a valve inlet opening and a valve outlet opening. The present invention&#39;s fluid valve device comprises a spherical object and two flow impedance units. The spherical object has running therethrough a diametric passage and is rotatable ninety degrees for adjustment between a fully closed valve position and a fully open valve position. The diametric passage is aligned with the valve inlet opening and the valve outlet opening when the fluid valve device is in the fully open valve position. The diametric passage is perpendicular to the valve inlet opening and the valve outlet opening when the fluid valve device is in the fully closed valve position. The two flow impedance units are an inlet flow impedance unit and an outlet flow impedance unit. Each flow impedance unit is characterized by flow path tortuosity for impeding fluid flow. The inlet flow impedance unit is situated at the valve inlet opening. The outlet flow impedance unit is situated at the valve outlet opening. The flow impedance units concertedly and decreasingly impede fluid flow during the adjustment of the fluid valve device from a first partially open valve position to a second partially open valve position. The flow impedance units cease to impede fluid flow upon the reaching of the second partially open valve position. 
   Typically according to such inventive embodiments, a third partially open valve position is intermediate said first partially open valve position and said second partially open valve position. During adjustment between the first partially open valve position and the third partially open valve position, the approximate totality of the fluid flow passing through the fluid valve passes through the two impedance units and the diametric passage. During adjustment between the third partially open valve position and the second partially open valve position, a first portion of the fluid flow passing through the fluid valve device passes through the two impedance units and the diametric passage, and a second portion of the fluid flow passing through the fluid valve device passes through the diametric passage without passing through the two impedance units. Further typically according to such inventive embodiments, during the adjustment of the fluid valve device from the first partially open valve position to the second partially open valve position (i.e., during adjustment between the first partially open valve position and the third partially open valve position, and between the third partially open valve position and the second partially open valve position), the flow impedance units together act so as to gradually reduce the pressure drop across the fluid valve device between the valve inlet opening and the valve outlet opening. 
   According to some such inventive embodiments, each flow impedance unit includes an odd number of at least three flat members, each flat member having at least one channel. At least two flat members each have at least one aperture. The flat members are abuttingly arranged so as to permit, through the flat members via the channels and between the flat members via the apertures, sequential fluid flow from the sequentially first flat member to the sequentially last flat member. The fluid enters the sequentially first flat member and exits the sequentially last flat member. The fluid is passable from each sequentially prior flat member to the sequentially subsequent flat member through the sequentially prior flat member&#39;s one or more apertures. The direction of the fluid flow alternates in two opposite flow directions between the sequentially odd-numbered flat members and the sequentially even-numbered flat members. 
   Opening noise is associated with typical operation of a conventional ball valve; the noise is generated when the ball valve opens a path from a high-pressure source on one side to a low pressure on the other side. The present invention represents a unique methodology for opening a ball valve under such conditions. The present invention&#39;s novel valvular apparatus typically describes a quietly opening ball-type valve assembly that opens against a large pressure differential across the valve in such a way as to preclude or limit the introduction of acoustic energy in the piping system. 
   According to many embodiments, the inventive ball valve device comprises a ball valve component and stacked disk-like members, wherein the fluid flow path is directed through the stacked disk-like members during the valve opening operation in order to reduce the generation of noise in the fluid under control. Diverse conduit systems can benefit from the present invention&#39;s quiet opening ball valve, which admits of a wide range of applications involving liquids and/or gases. 
   The present invention effects a kind of flow control whereby certain elements are used to produce several small pressure drops in transitioning from a high pressure to a low pressure. It would not be practical to constantly maintain elements of this nature in the main flow path of a valve, because the elements would be easily clogged and would continuously restrict the full flow once flow is established. The present invention uniquely features the implementation of elements of this nature so as to be operative for the initiation noise while a ball valve is opening, and so as to be inoperative (e.g., sealed off) subsequent to the initial opening by the ball valve&#39;s ball. 
   The present invention&#39;s “Quiet Opening Ball Valve” (“QOBV”) uniquely combines two concepts, viz., (i) the complete “openability” characterizing a full-close, full-open ball valve, and (ii) the tortuosity (and associated quietude) characterizing a throttling valve. A full-open ball valve-type component is associated with two throttling valve-type components, each providing a tortuous path for the fluid flow (The adjectives “tortuous,” “winding,” “twisting,” “serpentine,” “labyrinthine,” “sinuous,” “circuitous” and “convoluted” are similarly apt descriptions of this flow path). As the ball valve rotates open, the ball valve exposes its high-pressure side to the first tortuous path, which gradually decreases in resistance until the ball valve is fully opened, at which time the ball seals off the first tortuous path. Similarly, at the same time, the ball valve exposes its low-pressure side to the second tortuous path, which gradually decreases in resistance until the ball valve is fully opened, at which time the ball seals off the second tortuous path. 
   Accordingly, the present invention features the association of two high impedance units (e.g., disk stacks) with a ball valve analogue, wherein the two high impedance units are situated at the entrance and exit sides, respectively, of the ball valve analogue. The inlet-placed and outlet-placed disk stacks each provide a tortuous path through which the fluid will flow during the opening and closing cycles, respectively. The disk stacks effectuate only during earlier periods of opening and closing (that is, when leaving the fully closed or fully open position) and are sealed by the ball during later periods thereof (that is, when approaching the fully open or fully closed position). Advantageously, when the valve nears or approaches a fully open position, the ball seals the passages (channels) to the disk stacks, the flow restriction thus being akin to that of a normal ball valve. When the inventive valve is fully open, the flow restriction is equivalent to that of an open pipe, viz., nonexistent or virtually so. The present invention&#39;s QOBV reduces a large pressure differential and thereby affords reduced noise during valve opening or closing. The same high impedance operation is effected by the present invention whether (i) reducing the noise associated with the opening of the inventive valve or (ii) reducing the noise associated with the closing of the inventive valve. 
   Other objects, advantages and features of the present invention will become apparent to the person of ordinary skill in the art based on the following detailed description of the present invention when considered in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the present invention may be clearly understood, it will now be described, by way of example, with reference to the accompanying drawings, wherein like numbers indicate the same or similar components, and wherein: 
       FIG. 1  is a cross-sectional longitudinal view (in the axial-longitudinal direction of the associated piping) of an embodiment of the present invention&#39;s valve, particularly illustrating the inventive valve being in the fully closed position so that there is zero flow, both disk stacks (inlet disk stack and outlet disk stack) being completely sealed off. 
       FIG. 2  is a view, similar to that shown in  FIG. 1 , of the inventive valve shown in  FIG. 1 , particularly illustrating the inventive valve being in a slightly open position, the inventive valve thus being open to the disk stacks so as to initiate flow on both disk stacks. 
       FIG. 3  is a view, similar to that shown in  FIG. 1 , of the inventive valve shown in  FIG. 1 , particularly illustrating the inventive valve being in a less than fully open position but in a more open position than as shown in  FIG. 2 , the inventive valve thus remaining open to the disk stacks and being opened to the free flow areas of the valve so as to initiate free flow from and to the inlet and outlet sections of the pipe. 
       FIG. 4  is a view, similar to that shown in  FIG. 1 , of the inventive valve shown in  FIG. 1 , particularly illustrating the inventive valve being in a less than fully open position but in a more open position than as shown in  FIG. 3 , the inventive valve thus remaining open to the free flow areas of the valve but with both disk stacks becoming completely sealed off. 
       FIG. 5  is a view, similar to that shown in  FIG. 1 , of the inventive valve shown in  FIG. 1 , particularly illustrating the inventive valve being in the fully open position so that there is complete flow, both disk stacks remaining completely sealed off. 
       FIG. 6 ,  FIG. 7 ,  FIG. 8 ,  FIG. 9  and  FIG. 10  are plan views of the first, second, third, fourth and fifth disks, respectively, of the inlet disk stack shown in  FIG. 1  through  FIG. 5 . These disks can also be conceived to be the fifth, fourth, third, second and first disks, respectively, of the outlet disk stack shown in  FIG. 1  through  FIG. 5 . 
       FIG. 11  is a cross-sectional view of the inlet disk stack shown in  FIG. 1  through  FIG. 5 , also conceivably a cross-sectional view of the outlet disk stack shown in  FIG. 1  through  FIG. 5 . 
       FIG. 12  is a cross-sectional view of the inlet ball seat shown in  FIG. 1  through  FIG. 5 , also conceivably a cross-sectional view of the outlet ball seat shown in  FIG. 1  through  FIG. 5 , particularly illustrating individual conduits provided in the ball seat that connect with corresponding channels of the extreme disk plate which directly engages the ball seat. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference is now made to  FIG. 1  through  FIG. 5 , which demonstrate how the present invention efficaciously unites ball valve characteristics with throttling valve characteristics. Although the opening process of the present invention&#39;s “quiet opening ball valve” (“QOBV”)  100  emphasized herein, it is to be understood that the present invention&#39;s valvular positional “stages” described herein with reference to  FIG. 1  through  FIG. 5  occur regardless of whether valve  100  is in the process of opening or closing—i.e., regardless of the rotational direction of ball  30 . 
   Valve  100  includes a valve body  20 , a ninety-degree-rotatable spherical ball  30 , a ball seat  24 , an inlet stack  40   IN  and an outlet stack  40   OUT . According to typical inventive embodiments, ball  30 , inlet stack  40   IN  and outlet stack  40   OUT  will each be made of a metal or composite material, and ball seat  24  will be made of a rubber or other elastomeric material. Valve body  20  includes an inlet section  22   IN , an outlet section  22   OUT  and a chamber  26  therebetween. Inlet section  22   IN  and outlet section  22   OUT  correspond to the high pressure side and low pressure side, respectively, of valve  100 . Inlet section  22   IN  is connected to inlet pipe  50   IN . Outlet section  22   OUT  is connected to outlet pipe  50   OUT . Chamber  26  encompasses ball  30 . Inlet section  22   IN  contains inlet free flow area  44   IN  and inlet stack  40   IN . Inlet stack  40   IN  is attached to valve body  40  and positioned in inlet section  22   IN  so as to be capable of affecting inlet flow into valve body  20 . Outlet section  44   OUT  contains outlet free flow area  44   OUT  and outlet stack  40   OUT  Outlet stack  40   OUT  is attached to valve body  40  and positioned in outlet section  22   OUT  so as to be capable of affecting outlet flow out of valve body  20 . Ball seat  24  is attached to valve body  40  inside chamber  26 . 
   Chamber  26  is structurally “open” so as to permit access via free flow passages  44   IN  and  44   IN  on the inlet and outlet sides, respectively. Provided in seat  24  are at least two passages, wherein at least one passage (shown in  FIG. 1  through  FIG. 5  and  FIG. 12  as inlet chamber conduits  28   IN ) communicates with inlet stack  40   IN  and at least one passage (shown in  FIG. 1  through  FIG. 5  and  FIG. 12  as outlet chamber conduits  28   OUT ) communicates with outlet stack  40   OUT . A set of inlet chamber conduits  28   IN  connects the chamber  26  interior with a corresponding set of channels  44  of an extreme plate  42  of inlet stack  40   IN , thereby permitting conduction of the fluid from inlet stack  40   IN  to axial bore  32  when ball  30  is suitably positioned. Similarly, a set of outlet chamber conduits  28   OUT  connects the chamber  26  interior with a corresponding set of channels  44  of an extreme plate  42  of outlet stack  40   OUT , thereby permitting conduction of the fluid from axial bore  32  to outlet stack  40   OUT  when ball  30  is suitably positioned. According to the embodiment shown in  FIG. 1  through  FIG. 5 , inlet chamber conduits  28   IN  and outlet chamber conduits  28   IN  are passages each provided (on the inlet and outlet sides, respectively) within ball seat  24 , which comprise two equivalent coaxial rings  24   a  and  24   b  disposed between ball  30  and chamber  26  so as to hold ball  30  in place. In accordance with inventive principles, the conduits connecting the ball-containing medial chamber with the fluid-restriction-causing units can be provided in any of various ways. 
   Still with reference to  FIG. 1  through  FIG. 5  and also with reference to  FIG. 6  through  FIG. 12 , inlet stack  40   IN  and outlet stack  40   OUT  each represent an identical or similar assembly of identical or similar plates  42 . Because of their standardized or modular nature as practiced according to many inventive embodiments, plates  42  are also referred to herein as “disks”  42 , and stacks  40   IN  and  40   OUT  are also referred to herein as “disk stacks”  40   IN  and  40   OUT . The term “disk,” when used herein to be synonymous with the term “plate,” is not intended to imply roundness of shape, as in inventive practice the plates  42  less typically are curvilinear (e.g., round) and more typically are rectilinear (e.g., rectangular, such as shown in  FIG. 6  through  FIG. 11 ). Stacks  40   IN  and  40   OUT  are each shown to have the same length 1. 
   As depicted in  FIG. 6  through  FIG. 11 , each plate (“disk”)  42  has, on opposite sides or faces thereof, a flat side  43  and a grooved side  45 . Each plate  42  is configured, on its grooved side  45 , so as to include plural tortuous flow-conveying channels (grooves)  44 . As best shown in  FIG. 11 , each stack  40  has its plates  42  abuttingly arranged so that the grooved side  45  of a given plate  42  is adjacent the flat side  43  of the next plate  42 . The alternating directions of fluid flow through channels  44  are indicated by straight directional arrows g in  FIG. 1 . Each plate  42  in not only grooved with channels  44  but is also apertured with flow-through apertures  46  (shown in  FIG. 6  through  FIG. 10 ), located at the respective ends of channels  44 , so as to permit sequential fluid conveyance from each plate  42  via apertures  46  to the next plate  42 . Each plate  42  has a thickness t (as shown in  FIG. 11 ) which (as shown in  FIG. 1  through  FIG. 5 ) is concordant with the diameter d of inlet chamber conduits  28   IN  and  28   OUT . In each of stacks  40   IN  and  40   OUT , the plate  42  which is last in fluid conveyance sequence does not require (typically, does not have) apertures  46 . 
     FIG. 6 ,  FIG. 7 ,  FIG. 8 ,  FIG. 9  and  FIG. 10  show plates  42   a ,  42   b ,  42   c ,  42   d  and  42   e , respectively.  FIG. 6  through  FIG. 11  can be considered to be generally representative of either inlet stack  40   IN  or outlet stack  40   OUT . In each of stacks  40   IN  and  40   OUT  certain configurational relationships obtain, as best shown in  FIG. 11 . The grooved side  45  of plate  42   a  is contiguous the flat side  43  of plate  42   b . The grooved side  45  of plate  42   b  is contiguous the flat side  43  of plate  42   c . The grooved side  45  of plate  42   c  is contiguous the flat side  43  of plate  42   d . The grooved side  45  of plate  42   d  is contiguous the flat side  43  of plate  42   e . The flat side  43  of plate  42   e  is contiguous a flat inner wall portion  49  of a valve section  22 . Each flat inner wall portion  49  serves a similar function to that of a flat side  43  of a given plate  42  insofar as providing a contiguous barrier for a grooved side  45  of an adjacent plate  42 . Optionally, depending on the inventive embodiment, the flat side  43  of plate  42   a  is contiguous a stack endplate  47  which is perpendicularly connected to seat  24 . 
   With regard to fluid flow, fluid f proceeds essentially as follows. Fluid f: flows from inlet pipe  50   IN  so as to enter inlet section  22   IN ; enters inlet stack  40   IN  at entry openings  41   EN  of plate  42   a ; flows through the channels  44  of plate  42   a ; flows through the apertures  46  of plate  42   a ; flows through the channels  44  of plate  42   b ; flows through the channels  44  of plate  42   b ; flows through the apertures  46  of plate  42   b ; flows through the channels  44  of plate  42   c ; flows through the channels  44  of plate  42   c ; flows through the apertures  46  of plate  42   c ; flows through the channels  44  of plate  42   d ; flows through the channels  44  of plate  42   d ; flows through the apertures  46  of plate  42   d ; flows through the channels  44  of plate  42   e ; exits inlet stack  40   IN  through exit openings  41   EX  (which are extensions of channels  44 ) of plate  42   e ; flows through the apertures  46  of plate  42   e ; flows through the inlet chamber conduits  28   IN  of ball seat  24 ; flows through axial bore  32  of ball  30 ; flows through the outlet chamber conduits  28   OUT  of ball seat  24 ; enters outlet stack  40   OUT  at entry openings  41   EN  (which are extensions of channels  44 ) of plate  42   e ; flows through the channels  44  of plate  42   e ; flows through the apertures  46  of plate  42   e ; flows through the channels  44  of plate  42   d ; flows through the channels  44  of plate  42   d ; flows through the apertures  46  of plate  42   d ; flows through the channels  44  of plate  42   c ; flows through the channels  44  of plate  42   c ; flows through the apertures  46  of plate  42   c ; flows through the channels  44  of plate  42   b ; flows through the channels  44  of plate  42   b ; flows through the apertures  46  of plate  42   b ; flows through the channels  44  of plate  42   a ; exits outlet stack  40   OUT  at exit openings  41   EX  (which are extensions of channels  44 ) of plate  42   a ; flows from outlet section  22   OUT  so as to enter outlet pipe  50   OUT . 
   As shown in  FIG. 1  through  FIG. 5  and  FIG. 12 , seat  24  includes two coaxial seat rings, viz., lefthand seat ring  25 L and righthand seat ring  25 R, which are situated on opposite sides of geometric longitudinal valve body axis v, about which valve body  20  is approximately symmetrical. Each of seat rings  25 L and  25 R has provided therethrough a series of passages, viz., conduits  28 , which accord with the entry or exit locations  41  of the series of channels  46  of the plate  42  which is immediately associated with such seat ring. Lefthand seat ring  25 L is the seat  24  portion which includes inlet chamber conduits  28   IN . Righthand seat ring  25 R is the seat  24  portion which includes outlet chamber conduits  28   OUT . In comparison with a traditional ball valve, seat rings  25 L and  25 R are enlarged so as to provide a sealing surface between ball  30  and the respective disk stacks  40   IN  and  40   OUT . In each stack  40 , only the first and last plates  42  (e.g., plates  42   a  and  42   e  as shown in the figures) include openings  41 , for providing ingress or egress of fluid f with respect to such stack  40 , but do not include apertures  46 . The other plates  42 , intermediate the extreme plates  42 , each have apertures  46  that lead to the channels  44  of the next disk  42 . 
   Ball  30  has an axial bore  32 , a linear cylindrical hole or passage characterized by a circular cross-section. Ball  30  sits in its seat  24  so as to be bidirectionally rotatable ninety degrees as shown by arcuate bidirectional arrow r in  FIG. 1 . The manner in which ball  30  is rotated (e.g., manually such as by using a handwheel, not shown) will depend on the application, and various techniques for accomplishing such rotation will be apparent to the ordinarily skilled artisan who reads this disclosure. The geometric axis of axial bore  32  is indicated as bore axis b. Inlet section  22   IN  and outlet section  22   OUT  approximately define geometric longitudinal axes which approximately coincide with the geometric longitudinal valve axis v, which is approximately perpendicular with bore axis b when ball  30  is rotated to the fully closed valve  100  position (as shown in  FIG. 1 ) and which are approximately colinear with bore axis b when ball  30  is rotated to the fully open valve  100  position (as shown in  FIG. 5 ). 
     FIG. 1  through  FIG. 5  together illustrate how inventive valve  100  goes through four (typically, sequential) stages as ball  30  rotates through its 90° arc, ball  30  commencing in its zero-degree (fully closed) position (shown in  FIG. 1 ) and concluding in its ninety-degree (fully open) position (shown in  FIG. 5 ). Valve  100  is, in sequence: (stage I; see  FIG. 1 ) in a fluid-impassable condition (i.e., wherein no or practically no fluid crosses from inlet section  22   IN  to outlet section  22   OUT , or in other words wherein chamber  26  is sealed); (stage II, see  FIG. 2 ) in a fluid-passable condition wherein all or practically all of the fluid which crosses from inlet section  22   IN  to outlet section  22   OUT  is conveyed through inlet stack  40   IN , subsequently through bore  32 , and subsequently through outlet stack  40   OUT , such as shown in  FIG. 2 ; (stage III; see  FIG. 3 ) in a fluid-passable condition wherein some of the fluid which crosses from inlet section  22   IN  to outlet section  22   OUT  is conveyed through inlet stack  40   IN , subsequently through bore  32 , and subsequently through outlet stack  40   OUT , and wherein some other of the fluid which crosses from inlet section  22   IN  to outlet section  22   OUT  is conveyed through inlet section  22   IN  but not through (i.e., circumventive of) inlet stack  40   IN , subsequently through bore  32 , and subsequently through outlet section  22   OUT  but not through (i.e., circumventive of) outlet stack  40   OUT ; and, (stage IV; see  FIG. 4  and  FIG. 5 ) in a fluid-passable condition wherein all or practically all of the fluid which crosses from inlet section  22   IN  to outlet section  22   OUT  is conveyed through inlet section  22   IN  but not through (i.e., circumventive of) inlet stack  40   IN , subsequently through bore  32 , and subsequently through outlet section  22   OUT  but not through (i.e., circumventive of) outlet stack  40   OUT . 
   Inlet section  22   IN  includes two ways via which fluid can potentially flow, viz., inlet stack  40   IN  and inlet free flow area  49   IN . Similarly, outlet section  22   OUT  includes two ways via which fluid can potentially flow, viz., outlet stack  40   OUT  and outlet free flow area  49   OUT . During stage II, all of the fluid that crosses valve  100  flows through inlet pipe  50   IN , then through inlet stack  40   IN , then through inlet chamber conduit  28   IN , then through axial bore  32 , then through outlet chamber conduit  28   OUT , then through outlet stack  40   OUT , then through outlet pipe  50   OUT . During stage III, some but not all of the fluid that crosses valve  100  flows through inlet pipe  50   IN , then through inlet stack  40   IN , then through inlet chamber conduit  28   N , then through axial bore  32 , then through outlet chamber conduit  28   OUT , then through outlet stack  40   OUT , then through outlet pipe  50   OUT . The rest of the fluid that crosses valve  100  during stage III flows through inlet pipe  50   IN , then through inlet free flow area  49   IN , then through axial bore  32 , then through outlet free flow area  44   OUT , then through outlet pipe  50   OUT . During stage IV, all of the fluid that crosses valve  100  flows through inlet pipe  50   IN , then through inlet free flow are  26   IN , then through axial bore  32 , then through outlet free flow area  49   OUT , then through outlet pipe  50   OUT . 
   Thus, the present invention&#39;s valve  100  undergoes two fluid-passable stages, viz., stages II and III, wherein some amount or percentage of the fluid crossing valve  100  proceeds through inlet stack  40   IN  and outlet stack  40   OUT . As illustrated in  FIG. 2 , during stage II, all of the fluid crossing valve  100  flows through inlet section  22   IN  and outlet section  22   OUT  so as to flow only through inlet stack  40   IN  and outlet stack  40   OUT . As illustrated in  FIG. 3 , during stage III, some but not all of the fluid crossing valve  100  flows through inlet stack  40   IN  and outlet stack  40   OUT , and the rest of the fluid crossing valve  100  flows through inlet section  22   IN  and outlet section  22   OUT  without flowing through inlet stack  40   IN  and outlet stack  40   OUT . 
   The stage sequence I, II, III through IV corresponds to rotation of ball  30  in the direction of the “fully” (or, synonymously, “completely”) open valve  100  position (shown in  FIG. 5 ). For rotation of ball  30  in the direction of the fully closed valve  100  position (shown in  FIG. 1 ), the stage numbers are reversed; that is, the stage sequence IV, III, II through I corresponds to rotation of ball  30  in the direction of the fully closed valve  100  position. Each stage of the rotation of ball  30  between the fully closed valve  100  position (shown in  FIG. 1 ) and the fully open valve  100  position (shown in  FIG. 4 ) is associated with an acute (“minor”) rotational arc existing within the overall ninety-degree (“major”) rotational arc. Each rotational arc on the surface of ball  30  has an arc length that equals the product of the radius and the arc angle (viz., the central angle measured, e.g., in degrees or radians, at the center c of ball  30 ). As shown in  FIG. 5 , the stage I rotational arc angle is designated θ I ; the stage II rotational arc angle is designated θ II ; the stage III rotational arc angle is designated θ III ; the stage IV rotational arc angle is designated θ IV . 
   According to typical inventive embodiments, the fully closed valve  100  position (viz., the zero-degree valve  100  position) is not the only valve  100  position in which fluid is impassable across valve  100 . That is, corresponding to stage I, while ball  30  is rotating in either direction there exists a minor arc between the zero-degree valve  100  position and an acute-degree valve  100  position in which fluid remains impassable across valve  100 , while ball  30  is rotating in either direction. Moreover, the fully open valve  100  position (viz., the ninety-degree valve  100  position) is not the only valve  100  position in which fluid is passable across valve  100  in the absence of passability through inlet stack  40   IN  and outlet stack  40   OUT . That is, corresponding to stage IV, while ball  30  is rotating in either direction there exists a minor arc between an acute-degree valve  100  position and the ninety-degree valve  100  position in which fluid which flows across valve  100 , viz. does not flow through inlet stack  40   IN  and outlet stack  40   OUT . Similarly as depicted in  FIG. 1  through  FIG. 5 , according to some inventive embodiments the stage I rotational arc angle θ I  is a relatively small arc angle, on the order of five or less degrees of arc. 
   Inlet stack  40   IN  and outlet stack  40   OUT  each describe a tortuous path for the fluid flow. Inlet section  22   IN  corresponds to the high-pressure side of inventive valve  100 . Outlet section  22   OUT  corresponds to the low-pressure side of inventive valve  20 . During stage I, ball  30  and the chamber  24  wall act in concert so as to seal off the respective tortuous paths of stacks  40   IN  and  40   OUT ; hence, during stage I, neither stack  40   IN  nor stack  40   OUT  interacts with or otherwise affects fluid flow. During stage II and stage III, as ball  30  rotates openly, the high-pressure side is exposed to the tortuous path of inlet stack  40   IN , and the low-pressure side is exposed to the tortuous path of outlet stack  40   OUT . These respective fluidic exposures to tortuous stacks  40   IN  and  40   OUT  occur approximately or nearly simultaneously during stages II and III of the valve-opening process. Fluid flow resistance afforded by stacks  40   IN  and  40   OUT  gradually decreases until the stage III-stage IV transition point is reached (as shown in  FIG. 4 ), prior to when valve  100  is fully (ninety degrees of arc) opened (as shown in  FIG. 5 ). That is, during stages II and III, the respective tortuous paths of stacks  40   IN  and  40   OUT  each gradually decrease in resistance until valve  100  reaches stage IV, whereupon, similarly as in stage I, ball  30  and the chamber  24  wall together seal off both tortuous paths, stacks  40   IN  and  40   OUT  thus no longer affecting fluid flow. 
   During stage I (e.g., during the first few degrees of opening rotation), ball  30  is closed to every fluid pathway. Ball  30  openingly rotates during stage I until, at the inception of stage II, the disk stacks  40   IN  and  40   OUT  start to open to pipes  50   IN  and  50   OUT , respectively. During stage II, ball  30  is closed to both free flow areas  44   IN  and  40   OUT , and is increasingly opened to both disk stacks  40   IN  and  40   OUT , respectively situated on both sides of ball  30 . During stage II, stacks  40   IN  and  40   OUT  are decreasingly resistive to fluid flow. Considering stages I and II together, ball  30  travels through opening arcs of θ I  and θ II  degrees in stages I and II, respectively; therefore, ball  30  travels through an opening arc of θ I  degrees plus θ II  degrees (i.e., θ I +θ II ) until, at the inception of stage III, the free flow areas  44   IN  and  40   OUT  start to open to pipes  50   IN  and  50   OUT , respectively. During stage III, ball  30  remains open to disk stacks  40   IN  and  40   OUT  (which are decreasingly resistive during stage III) and is increasingly opened to both free flow areas  44   IN  and  44   OUT , respectively situated on both sides of ball  30 ). Similarly as in stage II, during stage III stacks  40   IN  and  40   OUT  are decreasingly resistive to fluid flow. During stage IV, ball  30  is closed to both disk stacks  40   IN  and  40   OUT , and is increasingly opened to both free flow areas  44   IN  and  44   OUT . 
   Valve body  20  is approximately symmetrical about a geometric longitudinal valve body axis v. Chamber  26 , valve inlet section  22   IN  valve outlet section  22   OUT  are each approximately symmetrical about valve body axis v. Bore  32  has an axis of symmetry b. The rotatability characterizing ball  30  describes a geometric valve body plane p (conceived to be the plane of the page in each of  FIG. 1  through  FIG. 5 ) in which both valve body axis v and bore  32  axis b can be conceived to lie. Plates  42  are situated approximately parallel with respect to valve body axis v. Plates  42  are situated approximately perpendicular with respect to valve body plane p. Inlet stack  40   IN  and outlet stack  40   OUT  are each traversed (e.g., bisected) by valve body plane p. Inlet and outlet stacks  40   IN  and  40   OUT  are located approximately oppositely with respect to valve body axis v. At the conclusion of stage IV of valve  100  opening operation, the geometric axis b described by axial bore  32  approximately coincides with the geometric axis v generally described by valve body  20 . That is, while ball  30  is in the ninety-degree ball axis b orientation, ball axis b is approximately coincident with valve body axis b, and the fluid is permitted to flow generally linearly through valve inlet section  22   IN , bore  32  and valve outlet section  22   OUT . 
   Disk stacks  40   IN  and  40   OUT  each configurationally describe a tortuous fluid path that can be designed, depending on the inventive embodiment, to effect (during stages II and III) practically any pressure drop across each such stack as may be desired. Disk stacks  40   IN  and  40   OUT  each represent a kind of high impedance element at the inlet and outlet (discharge) sides, respectively, of ball valve  100 . Each of stacks  40   IN  and  40   OUT  has channels  44  and apertures  46  wherein apertures  46  are located at the extremities of channels  44 . This series of channels  44  and apertures  46  provides the desired high impedance particularly during the stage II opening, and also during the stage III opening, of valve  100 . By providing respective tortuous paths for the fluid, stacks  40   IN  and  40   OUT  act in concert during stage II so as to initially reduce the fluid velocity and so as to gradually reduce the fluid pressure from the high-pressure (inlet) side to the low-pressure (outlet) side. On the high-pressure side, disk stack  40   IN  is flooded prior to the opening of valve  100 . When ball  100  rotates past the conduits  28   EX  of disk stack  40   IN , fluid flow is initiated. Since the fluid path is through both sets of disk stacks  40 , the initial velocity will be lower than that which would be associated with a traditional kind of valve opening system which directly leads to and from the pipes. Typically, the present invention&#39;s total pressure drop from high pressure to low pressure will be the same, as compared with the total pressure drop associated with a traditional valve, however, according to typical embodiments of the present invention, the total pressure drop will occur in the passages over several small steps or increments, thereby reducing the cavitation in the fluid, which can be a significant source of noise. 
   During stage II, as ball  30  continues to rotate, the channels  44  of each plate  42  open to the channels  44  of the next plate  42 . Thus, in each of disk stacks  40   IN  and  40   OUT , each succeeding set of channels  44  is opened, thereby allowing more fluid flow through the plate  42  channels  44  of such stack. In each of stacks  40   IN  and  40   OUT , in the process of the ball  30  rotation during stage II, the additional tortuous path increases the flow area and decreases the pressure drop through such stack. Just before the commencement of stage III (at which point ball  30  begins to open to pipes  50   IN  and  50   OUT , respectively, as shown in  FIG. 3 ), each of stacks  40   IN  and  40   OUT  has approximately five percent pipe flow through such stack. Thus, when ball  30  opens to the inlet and outlet free flow areas  26   IN  and  26   OUT  (of valve sections  22   IN  and  22   OUT , respectively), flow will already have been established, thereby reducing the pressure drop across valve  100  and concomitantly reducing the opening noise. At the commencement of stage IV, shown in  FIG. 4 , ball  30  begins to completely seal off the flow path through stacks  40   IN  and  40   OUT . During stage IV, ball  30  is completely sealed to stacks  40   IN  and  40   OUT , and axial bore  32  admits and transmits fluid flow solely via the inlet and outlet free flow areas  26   IN  and  26   OUT  (of valve sections  22   IN  and  22   OUT , respectively). As shown in  FIG. 5 , valve  100  is fully opened, ball  30  continuing to completely seal off the flow path through stacks  40   IN  and  40   OUT . Thus, when valve is in the fully open position as shown in  FIG. 5 , the flow path is left fully open in a manner similar to that of a traditional ball valve. 
   In conventional practice, ball valve opening time has been proven to affect the level of the opening noise. Accordingly, in inventive practice, depending on the pressure drop across the inventive valve  100 , the opening time of valve  100  can be varied. A large pressure drop will require a slow valve  100  opening to take advantage of the disk stacks  40   IN  and  40   OUT  so as to release the pressure across the valve  100 . This can be achieved by hydraulic operation of the valve  100  or by changing from a manual valve actuator to an electric valve actuator. With recent advances in electronic valve actuation, the valve  100  opening could precisely be controlled. For many inventive embodiments, an extended valve  100  opening time (e.g., a few seconds between a fully closed stage I position and a fully open stage IV position) should provide the disk stacks  40   IN  and  40   OUT  a sufficient amount of time to suitably reduce the pressure drop across the valve  100  during stage II while establishing flow through the valve  100  prior to the commencement of stage III, at which point ball  32  begins to open to the free flow areas  26   IN  and  26   OUT  of valve sections  22   IN  and  22   OUT , respectively. 
   Disk stacks  40   IN  and  40   OUT  can be tailored to suit a required pressure drop or flow rate, depending upon the embodiment of the present invention; in particular, inventive disk stack parameters which can be modified, as required, include: the number of plates (“disks”)  42  in each of disk stacks  40   IN  and  40   OUT ; the number of channels  44 ; the number of flow-through apertures  46 ; the sizes (e.g., length and/or width) and configurations of channels  44  (e.g., the shape or arrangement of the overall tortuous path provided by the channels  44  of a plate  42 ); the sizes (e.g., diameter) and configurations of flow-through apertures  46 . For instance, each plate  42  is shown herein, in a preferred inventive embodiment, to be provided with five tortuous channels  44 , wherein four channels  44  are similar and the middle channel  44  differs from other four channels  44 . However, the numbers and shapes of channels  44  per plate  42  are variable; depending on the inventive embodiment, an individual plate  42  can include one or any plural number of channels  44  which can be characterized by any among diverse combinations of homogenous or heterogeneous shapes and configurations. 
   Other embodiments of this invention will be apparent to those skilled in the art from a consideration of this specification or practice of the invention disclosed herein. Various omissions, modifications and changes to the principles described herein may be made by one skilled in the art without departing from the true scope and spirit of the invention which is indicated by the following claims.