Abstract:
A ball valve includes a bonnet and a removable insert in which a valve ball and opposed seat rings are contained within a cartridge of separable shells. Cylindrical spring seals of resilient and impervious high density graphite or silicon ruber are mounted on a reduced diameter length of each seat ring. Other embodiments include annular coil springs which compensate for component wear, and contraction and expansion due to changes in temperature. The spring seals are compressed between shoulders on the seat rings and a facing annular recessed surfaces in the cartridge and urge the seat rings into dynamic sealing contact with the valve ball. The spring seals also provide static sealing at the interface of the seat rings and the cartridge. Connecting fittings on mating surfaces of the bonnet and the insert enable the insert to be completely removed from the valve body for easy access for repair or replacement of components within the cartridge.

Description:
RELATED APPLICATION  
       [0001]    This is a continuation-in-part application of application Ser. No. 09/332,431 filed Jun. 14, 1999. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to ball valves, and more particularly to an improved valve construction having a valve body with a novel replaceable valve plug and cartridge insert which is particularly suitable for use under extreme conditions of temperature and pressure.  
         BACKGROUND OF THE INVENTION  
         [0003]    Many ball valves have removable covers or bonnets to permit access to the interior of the valve body for replacing defective or worn plugs and seals without having to dismantle the entire valve from a pipe line. U.S. Pat. No. 3,195,560 to Pofit discloses such a top entry ball valve in which a rotatable spherical plug is seated within the valve body between annular dynamic seat rings. The rings are urged against the plug by externally disposed springs acting between the rings and the valve body. With the valve cover removed, the plug must be extracted before the seat rings or the springs can be replaced. A modification of this design uses a cartridge type insert. The valve plug and seat rings are pre-assembled in a conical cartridge of two half shells. By this arrangement, the critical components can be easily installed as one unit in the valve body. For example, U.S. Pat. No. 2,885,179 to Hartmann shows a top entry ball valve in which the plug and seat rings are preassembled between two half shells to form a cylindrical cartridge which can be inserted in the valve body as one unit. The dynamic sealing effect obtains from resilient annular packings on opposite external sides of each seat ring compressed between the plug and the interior of the valve body. U.S. Pat. No. 5,135,019 to DuPont similarly discloses a top entry ball valve designed for use in deep water. The spherical plug and seat rings are preassembled within a tapered cartridge of two half shells for replacement in the valve body as a single cartridge insert. The seals are pressed against opposite external sides of the plug by dish-type spring washers and resilient static seals acting in series between the plug and the valve body. U.S. Pat. No. 4,587,990 to Pennell et al. discloses a top entry ball valve in which the spherical plug, seat rings and a plurality of spiral springs are preassembled within a tapered cartridge of half-shells for inserting in the valve body. The seat rings include a plurality of circumferentially spaced bores which receive the springs and act against the interior of the cartridge to urge the seat rings into sealed engagement with the plug. U.S. Pat. No. 4,796,858 to Kabel shows bottom entry valve in which a tapered inserts are disposed on opposite sides of a cylindrical plug  
           [0004]    In each of these valves there are no springs which are completely contained within the cartridge insert and which serve as a positive seal as well. Rather, the spring elements must be installed external to the cartridge insert, or a plurality of springs must be pre-installed around each seat ring or insert before being inserted in the valve body.  
         OBJECTS OF THE INVENTION  
         [0005]    Accordingly, it is an object of the present invention to provide a novel ball valve construction in which the internal components are completely preassembled as an insertable cartridge for easy replacement or repair without dismantling the valve body from an installation, and in which unique spring seals are isolated from the valve body to maintain a positive dynamic seal.  
           [0006]    Another object of the invention is to provide a readily replaceable plug and sealing mechanism in a ball valve construction in which the sealing force applied to the plug is independent of the valve body.  
           [0007]    Still another object is to provide a ball valve insert in which the plug and spring sealing mechanisms are totally enclosed within an easily assembled cartridge.  
           [0008]    A further object is to provide a ball valve construction in which internal components can be readily replaced without removing the valve body from a fluid line.  
           [0009]    Another object is to provide a ball valve construction in which an insertable cartridge is retained by the valve bonnet during insertion and extraction from the valve body.  
           [0010]    Still another object is to provide a complete and removable cartridge insert for a ball valve which can operate continuously under sustained conditions of high temperatures and pressures.  
           [0011]    Yet another object of the invention is to provide a ball valve construction having a cartridge insert, with fully enclosed seal springs, which can be replaced or repaired without dismantling the valve actuating mechanism for the valve body.  
         SUMMARY OF THE INVENTION  
         [0012]    Briefly, these and other objects and novel aspects of the invention are accomplished by an insert for a ball valve body and bonnet in which a spherical valve plug and seat rings are assembled in a cartridge of mating shells.  
           [0013]    In one embodiment, cylindrical spring seals of resilient and impervious high density graphite or silicon rubber, are mounted on a reduced diameter section of the seat rings between a shoulder on the seat rings and an annular recessed surface of the cartridge for urging the seat rings into sealing contact with the plug. The spring seals also provide a positive seal at the interface of the seat rings and the cartridge.  
           [0014]    In other embodiments, push rings and annular coil springs are interposed between the graphite or rubber spring seals and the recessed surfaces of the cartridge to increase the spring and sealing effect of the spring seals. Connecting fittings on the mating surfaces of the valve bonnet and the insert enable the insert to be removed from the valve body while attached to the bonnet and valve actuating mechanism, and then disconnected for replacement of worn components. An alternative configuration allows the cartridge insert to be removed completely without dismantling the actuating mechanism from the bonnet or valve body. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    For a better understand of the invention, reference will be made to the following detailed description taken in conjunction with the accompanying drawings wherein:  
         [0016]    [0016]FIG. 1 represents a longitudinal sectional view of a ball valve according to the invention with a top entry removable cartridge insert in the open position;  
         [0017]    [0017]FIG. 2 is a view in cross section of the ball valve taken along the line  2 - 2  of FIG.1;  
         [0018]    [0018]FIG. 3 is an exploded perspective view of component parts of the ball valve of FIG. 1;  
         [0019]    [0019]FIG. 4 is an enlarged view in cross section of a portion of the valve seat and seal spring of FIG. 2;  
         [0020]    [0020]FIG. 5 is an enlarged view in cross section of a bonnet-cartridge connector in the ball valve taken along the line  5 - 5  of FIG. 1.  
         [0021]    [0021]FIG. 6 is a view in cross section of the bonnet-cartridge connector taken along the line  6 - 6  of FIG. 5;  
         [0022]    [0022]FIG. 7 is a view in cross section like FIG. 2 of an alternate bonnet-cartridge connector for the ball valve of FIG. 1 according to the invention.  
         [0023]    [0023]FIG. 8 is a longitudinal view in cross section of another embodiment of a ball valve according to the invention with a top entry cartridge insert secured by a pull nut;  
         [0024]    [0024]FIG. 9 is an enlarged view in cross section of a portion of the ball valve of FIG. 8;  
         [0025]    [0025]FIG. 10 is an exploded view of component parts of the ball valve of FIG. 8.  
         [0026]    [0026]FIG. 11 is an external view of another embodiment of a two-way ball valve according to the invention;  
         [0027]    [0027]FIG. 12 is a cross sectional view of the ball valve of FIG. 11 taken along the line  12 - 12  thereof;  
         [0028]    [0028]FIG. 13 is a cross sectional view of the ball valve of FIG. 11 taken along the line  13 - 13  of FIG. 12;  
         [0029]    [0029]FIG. 14 is a view in longitudinal cross section of another embodiment of a ball valve according to the invention having a top entry cartridge insert with a composite spring seals;  
         [0030]    [0030]FIG. 14A is an enlarged fragmentary section of a seal of FIG. 14;  
         [0031]    [0031]FIG. 15 is a view of an alternate embodiment of the composite spring seal of FIG. 14A; and  
         [0032]    [0032]FIG. 16 is a view in longitudinal cross section of another embodiment of a bottom entry ball valve according to the invention with a cartridge insert and composite spring seals. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]    Referring now to the drawings, wherein like reference characters denote like or corresponding parts throughout the several views, FIGS.  1 - 6  represent one embodiment of a ball valve  10  comprising a valve body  12  with aligned inlet and outlet flow passages  14  terminating at opposite ends with flanges  12   a  for installing in a flow line. A frustoconical cavity  16  formed between the flow passages on a central axis normal thereto tapers outwardly from a blind end  16   a  to a top entry  16   b  formed to receive an insert including a cartridge insert  20  of two semicircular half-shells  20   a  and  20   b  joined together by fasteners  22  and retained in valve body  12  by a bonnet  18 . Cartridge  20  forms an outer surface tapered to fit contiguously in cavity  16 . Each half-shell  20   a  and  20   b  respectively includes a port  21   a  and  21   b  for communicating between the flow passages  14 . Ports  21   a  and  21   b  are aligned with passages  14  by two studs  24  each threaded at one end into the base of bonnet  18  and the other end insertable into aligned blind holes  26  in the abutting faces of half-shells  20   a  and  20   b . As best seen in FIGS. 5 and 6, each stud  24  is retained in a blind hole  26  by a pin  28  inserted through a respective half-shell  21   a  or  21   b  to engage opposite sides of a continuous groove  24   a  around the stud  24 . Cartridge  20  is thereby concurrently removable with bonnet  18  from valve body  12 , and separable from bonnet  18  upon removal of pins  28 . Annular seals  34 , bonded to the curved surfaces of cartridge  20  around ports  21   a  and  21   b , prevent fluid in passages  14  from escaping through the interface of cartridge  20  and valve body  12 .  
         [0034]    Cartridge  20  houses a valve ball  40  with engaging surfaces  20   c  and lower and upper journals  42  and  43  for rotation in bushings  44  on an axis normal to the length of passages  14 . A bore  41  through ball  40 , preferably of the same diameter as passages  14 , aligns with ports  21   a  and  21   b  when rotated 90 degrees from a closed position to a fully open position as shown.  
         [0035]    As best seen in the portion of half-shell  20   b  shown in FIG. 4, each half-shell  20   a  and  20   b  has a valve seat ring  46 , slidable in an annular recess  47  around port  21   a  and  21   b , respectively. Surfaces  46   a  on rings  46  are urged axially against opposite sides of valve ball  40  by annular spring seals  48  which are axially compressed between shoulders  52  around recesses  47  and shoulders  53  around seats  46 . Positive seals between valve ball  40 , valve body  12  and seats  46  are thereby maintained independent of the position of cartridge  20  relative to and the wall of cavity  16 . The material selected for seat rings  46  is preferably a metal composite suitable for use under extreme conditions of heat and chemical exposure such as duplex alloys and stainless or CrMo steels. Spring seals  48  are preferably made of a resilient and impervious material such as high density graphite or a silicone rubber for both resilience and sealing. A most preferred material is an elastically-compressible, expanded graphite having a precompressed density in a range of about 1.4 to about 2.2 g/cm 3 , and a compressed density in a range of about 0.9 to 1.2 g/cm 3 .  
         [0036]    Bonnet  18 , with cartridge  20  attached, is secured to the top of valve body  12  by nuts  30  and washers  31  threadingly tightened on four corner studs  32  to sealingly compress annular seals  34  and a ring gasket  36  between the interfaces of cartridge  20 , valve body  12  and bonnet  18 . A valve stem  54  extends through a bore  55  bonnet  18  and includes a key  54   a  interlocking with a mating slot  43   a  in upper journal  43  for transmitting rotation of stem  54  to valve ball  40 . A thrust bearing  56  between a shoulder  54   b  on stem  54  and a shoulder in bore  55  sustains axial loading and restricts upward movement of stem  54 . Conventional components such as stem seal  57 , packing  58  and gland  59  are compressed against a shoulder of base  55  by a packing flange  60  and six bolts  61  (only one shown) threaded into the upper end of bonnet  18  to prevent leakage around stem  54 .  
         [0037]    A lever  62  pivotally connected to valve stem  54  by a pin  63  provides for manual opening and closing valve ball  40 . A stop  64  extending from the top of bonnet  18  engages leaver  62  when bore  41  of valve ball  40  is in a fully open position aligned with passages  14 .  
         [0038]    As described, the components within cartridge  20  are preassembled for quick and easy replacement or repair of parts without dismantling valve body  12  from a pipe line. In assembly, valve ball  40 , bushings  44 , seats  46  and spring seals  48  are placed between half-shells  20   a  and  20   b . As the shells are drawn together by fasteners  22 , compression of spring seals  48  positively urges seals  46  against ball  40  creating a dynamic seal. With seals  34  bonded around each port  32 , cartridge  20  is attached to bonnet  18  by studs  24  and pins  28  and then inserted into cavity  16 . Stem  54 , thrust bearing  56  and bonnet seal  36  are then secured in place with bonnet  18  secured to valve body  12  by nuts  30 . Cartridge  20  and bonnet  18  are easily removed from valve body  12  as a single unit by removing nuts  30 . Then cartridge  20  may be separated from bonnet  18  by removing pins  28  and disassembly by removing fasteners  22 .  
         [0039]    [0039]FIG. 7 shows an alternative means for securing a cartridge  20 ′ to bonnet  18 ′. The joined half-shells  20   a  ′ and  20   b  ′ form a round boss  23  insertable in a mating recess  18   a  of an annular extension  18   b  on the facing surface of bonnet  18 . Set screws  27  spaced around extension  18   b  engage a peripheral groove  23   a  around boss  23  to secure cartridge  20 ′ to bonnet  18 ′.  
         [0040]    [0040]FIGS. 8, 9 and  10  disclose another embodiment of a ball valve  70  which is particularly suitable for use in chemical and pharmaceutical processes. It comprises a valve body  71  with aligned inlet and outlet passages  72  communicating with a frusto-conical cavity  74  open at both ends and tapering outward toward the top opening  71   a  on a central axis normal to the length of passages  72 . A cartridge  76 , comprising a frustoconical shell  76   a  with a recess  76   c  intermediate its length, receives a semicircular shell  76   b  to form a continuous conical surface mating with the surface of cavity  74 . With cartridge  76  fully inserted in cavity  74 , a reduced diameter threaded end  76   d  of shell  76   a  extends through the bottom opening of cavity  74  and is secured by a gasket  78 , pull nut  79  and screws  80 .  
         [0041]    Shells  76   a  and  76   b  include ports  82   a  and  82   b  which register with passages  72  by a guide pin  84  radially extending from the periphery of shell  76   a  and seated in a radial groove  85  in valve body  71 . An annular static seal  86   a  bonded on the curved surface of shell  76   a  around port  82   a  seals the interface of cartridge  76  and valve body  71 . Another static seal  86   b,  bonded to the curved surface around port  82   b  and overlapping the peripheral juncture of shells  76   a  and  76   b  provide seals at the interface of both shells  76   a  and  76   b  and valve body  71 .  
         [0042]    Like ball valve  10  of FIGS.  1 - 3 , cartridge  76  and its installed components are completely removable from cavity  74  without the dismantling valve body  71  from a pipe line by removing pull nut  79 . A valve ball  88  with lower and upper journals  89   a  and  89   b  are rotatably supported in bushings  90  within cartridge  76  on an axis normal to the flow path through inlet and outlet passages  72 . A bore  91  through ball  88  preferably the same diameter as passages  72 , align with ports  82   a  and  82   b  when rotated 90 degrees from a closed position to a fully open position as shown. Seat rings  92  and annular spring seats  94  are arranged in cartridge  76  like similar parts in valve  10  of FIG. 4 and act in the same manner to maintain a positive seal between ball  88  and seat  92  as well as a seal between seat rings  92  and said cartridge  76 .  
         [0043]    Purging the contacting surfaces of valve ball  88  and seat rings  92  of contaminants is provided by introducing a cleaning fluid such as steam under pressure through a conduit  96  to a channel  97  (FIG. 9) encircling one of seat rings  92  and communicating with the interface of both seat rings  92  and ball  88 . The pressure causes the cleaning fluid to pass through the gaps G in the interfaces and discharge with purged matter into inlet and outlet passages  72 . Seals  98  prevent the cleaning fluid from leaking past the interface of journals  89  and cartridge  76 .  
         [0044]    A bonnet  100  secures stem  54 ′, gasket  98 , bushings  90 , stem cap  104 , thrust ring  56 ′ and ring gasket  36 ′ in place with six bolts  106  screwed into threaded holes  106   a . (FIG. 10). Packing  58 ′, gland  59 ′ and spring washer  66  are compressed against an annular boss  108  by a packing flange  110  and six bolts  112  screw into threaded holes  112   a . Valve ball  88  is manually rotated by an actuating lever  114 . But for the upper end of stem  54 ′ ; the entire upper section of the ball valve  70  is insulated from ambient atmosphere by a cover  116 , secured by set screws  117 , and upper and lower seals  118 . Valve ball  88  is manually rotated by an actuating lever  114  which is limited in rotation in the fully open position by a stop  119  extending from the top of cover  116 .  
         [0045]    Referring now to FIGS. 11, 12, and  13 , the inventive concept is shown applied to a two-way ball valve  120  having a valve body  122  with radially spaced ports  122   a, b  and  c  arranged along a single plane and communicating with a conical cavity  122   d  extending on an axis normal to the plane. Three arcuate segments  123   a, b  and  c  are joined to form a tapered cartridge  123  matching the shape of cavity  122   d  and inserted therein. Like half-shells  20   a  and  20   b  of FIGS.  1 - 3 , each segment  123   a, b  and  c  has a valve seat ring  124  inserted in an annular recess, and an annular spring seal  126  compressed between a shoulder  55  (FIG. 4A) on seat ring  124  and an annular recess  52  (FIG. 4A) in segment  123   a, b  or  c.    
         [0046]    A valve ball  128  is rotatably retained within cartridge  123  and includes a bore  126   a  angled to direct flow between a selected pair of ports  122   a, b  and  c,  the selection being made by rotation of lever  130  through a valve stem  132  engaged at the rotational axis of valve ball  126 .  
         [0047]    If desired, a four-way ball valve (not shown) may be provided in accordance with the teachings of the present invention simply by increasing the number of cartridge members accordingly.  
         [0048]    Referring to FIGS. 14 and 14A, there is shown a ball valve  200  which is particularly suited for operation at high pressures and temperatures (over 300° C.). The valve comprises a valve body  202  having a frustoconical cavity contiguously receiving a cartridge insert  204  of two tapered semicircular half-shells  206  joined at facing planar sides by four threaded fasteners (not shown) inserted along parallel center lines F-F and retained in valve body  202  by a bonnet  207 . Ports  206   a  in respective half-shells  206  coaxially align in communication with the flow passage of valve body  202 . Seals  208  bonded to the outer surfaces of half-shells  206  around the ports  206   a  provide a tight static seal between valve body  202  and cartridge insert  204 .  
         [0049]    Cartridge insert  204  contains a valve ball  210  journaled in upper and lower bushings  212  between opposed annular valve seats  214  for rotation on an axis A-A normal to the flow passage of valve body  202 . A bore  210   a  through the valve ball axially aligns with opposed ports  206   a  when rotated 90° about axis A-A from a closed position to the open position shown.  
         [0050]    As best seen in FIG. 14A, each valve seat  214  is slidable in an annular recess  206 b around a respective port  206   a  and is urged against valve ball  210  in a controlled amount by the combined compression of an annular spring seal  216 , mounted on a valve seat shoulder  214   a , and an annular coil spring  218  between shoulders  206   c  and  214   b  of half-shell  206  and valve seat  214 . A push ring  220  slidable on valve seat shoulder  214   a  is interposed between spring seal  216  and coil spring  218 . The opposite sides of coils spring  218  make circular line contact with the facing surfaces  220   b  of push ring  220  and  206   c  of half-shell  206 . The amount of compression contributed by coil spring  218  is limited by engagement of facing surfaces  214   c  and  220   a  of valve seat  214  and push ring  220 , respectively. Seats  214  and seals  216  are preferably of the same materials as described in the ball valve of FIG. 1. Coil spring  218  is preferably made of a nickel-chromium-cobalt spring alloy having a stress-rupture and creep resistance to about 1700° F. (920° C.). A coil spring found suitable for the present application is made of Nimonic alloy 90® by Helicoflex Company/Cefilac Etancheite.  
         [0051]    Whereas the cartridge assemblies of FIGS. 1 and 8 employ one spring seal at each valve seat, cartridge insert  204  employs a unique combination of a spring seals and coil spring for maintaining positive sealing at each valve ball-valve seat interface under extreme fluid temperatures and pressures. Compression by coil spring  218  is continuously applied against valve seat  214  with different rates of expansion and contraction and compensates for any wear between the contacting surfaces of valve seat  214  and valve ball  210 . However, if the contraction or wear exceeds a predetermined limit, the force of coil spring  218  becomes ineffective.  
         [0052]    Bonnet  207  and cartridge insert  204  are secured to valve body  202  by nuts  222  threadedly tightened on four corner studs  223  (two shown) extending from valve body  202 . A bonnet ring seal  224 , compressed between bonnet  207  and valve body  202  by gland follower  226  and packing screws  228 , seals the interface. A valve stem  230  extends through bonnet  207  and interlocks with valve ball  210  for transmitting rotation about ball axis A-A. A thrust washer  232  and stem cover  234  acting against a shoulder in bonnet  207  sustains axial loading and restricts upward movement of valve stem  230 . Valve stem  230  is sealed against leakage by conventional components such as disclosed for the valve stems in the embodiments of FIGS. 1 and 8.  
         [0053]    Like the embodiments of FIGS. 1 and 8, cartridge insert  204  may be quickly and easily installed and removed without dismantling entire ball valve  200 . The components are assembled essentially the same way but with the addition of push rings  220  and coil springs  218 .  
         [0054]    [0054]FIG. 15 shows another construction of the seal arrangement within the cartridge insert in which a valve seats  214 ′ each has a second annular shoulder  214   b′  encircled by a push ring  220 ′ as it slides along a first shoulder  214   a′ . The degree of compression contributed by coil spring  218  is limited by the interfacing surfaces  214   c′  and  220   a′.    
         [0055]    Referring now to FIG. 16, there is illustrated a ball valve  300  which allows the cartridge insert to be replaced without dismounting the valve activating mechanism or instrumentation system. A valve body  302  includes aligned inlet and outlet passages  304   a  and  304   b  communicating through a frustoconical cavity  306  which tapers outwardly from an annular boss  306   a  to a bottom entry opening  306   b.  A cartridge insert  308  received in opening  306   b  includes two joined half-shells  308   a  and  308   b  with respective ports  310   a  and  310   b  aligned with inlet and outlet passages  304   a  and  304   b.  Half-shells  308   a  and  308   b  include upper and lower journal bearings  312   a  and  312   b  which rotatably support a valve ball  312  between the half-shells on an axis normal to the length of passages  304   a  and  304   b.  A bore  314  through ball  312  aligns with ports  310   a  and  310   b  when rotated 90 degrees from a fully closed position to a fully open position as shown. Cartridge insert  308  is retained in sliding contact with cavity  306  by a bonnet  316  sealingly secured by fasteners  320  around the bottom entry opening  306   b.  A valve stem  318  extending through the top of valve body  302  engages a key slot  322  and is connected to a hand lever  324  for manually actuating valve  300 . Composite coil spring seals  326  are of the same construction as the seals described in the embodiment of FIG. 15.  
         [0056]    Some of the many advantages and novel features of the invention should now be readily apparent. For instance, ball valve construction is provided in which the plug and seal components are preassembled and totally enclosed within a cartridge insert for easy replacement or repair without dismantling the valve body from an installation. The cartridge insert maintains positive dynamic sealing by a unique arrangement of spring seals which are isolated from the valve body and are completely independent of the valve body. The cartridge insert may be readily replaced without dismantling the valve body from a fluid line and replaced separately without dismantling the actuating mechanism from the valve body. The materials of construction used in the spring seals enables the valve to operate continuously under sustained conditions of high temperatures and pressures.  
         [0057]    While preferred embodiments of the invention have been described in detail, various modifications, alterations and changes may be made within the scope of the invention as defined in the appended claims.