Abstract:
According to one aspect of the teachings herein, a ball valve assembly provides a primary flow path and a secondary flow path, where the primary flow path is established by moving the valve into a defined first position and the secondary flow path is established by moving the valve into a defined second position. The secondary flow path substantially restricts fluid flow as compared to the primary flow path and may be regarded as a trickle flow path. In a non-limiting example, the ball valve assembly is used on a water service line and is operated by a utility company. The valve is placed in its first position by authorized personnel, to provide normal, full-flow water service to a residence or other structure, and is placed in its second position, to provide restricted, low-flow water service to the structure.

Description:
TECHNICAL FIELD 
       [0001]    The present invention generally relates to valve assemblies for controlling fluid flows, and particularly relates to ball valve assemblies, such as may be used for controlling the flow of water in a water line. 
       BACKGROUND 
       [0002]    Shut-off valves find widespread use in a variety of industries and across a wide range of fluidic applications. In an example application, public utility companies commonly use curbside valves to control whether or not individual residences are supplied with water. These valves provide on/off functionality in the sense they generally operate in one of two positions: an open position in which the valve allows the full rated flow of water into the residence, and a closed position in which the valve completely shuts off water flow into the residence. 
         [0003]    Utility companies shut off water service for a variety of reasons, such as when a structure becomes unoccupied or unused, or when the involved customer fails to pay the water bill. However, the disconnection of water service to a residence may be undesirable because of humanitarian considerations, or may not be permissible in view of applicable laws. In this context and others, the instant inventors have recognized that, paradoxically, it may be desirable for a shut-off valve to provide a position where it does not completely shut off fluid flow, while at the same time greatly restricting the maximum flow rate through the valve. 
       SUMMARY 
       [0004]    According to one aspect of the teachings herein, a ball valve assembly provides a primary flow path and a secondary flow path, where the primary flow path is established by moving the valve into a defined first position and the secondary flow path is established by moving the valve into a defined second position. The secondary flow path substantially restricts fluid flow as compared to the primary flow path and may be regarded as a trickle flow path. In a non-limiting example, the ball valve assembly is used on a water service line and is operated by a utility company. The ball valve assembly is placed in its first position by authorized personnel, to provide normal, full-flow water service to a residence or other structure, and is placed in its trickle position, to provide restricted, low-flow water service to the structure. Further, in one or more embodiments, the valve has a defined third position in which it completely shuts off flow through the assembly. 
         [0005]    In an example embodiment, a ball valve assembly has a primary flow path running from a fluid inlet of the ball valve assembly to a fluid outlet of the ball valve assembly and a ball disposed within the primary flow path that is operable when rotated into a defined first position to duct fluid from the fluid inlet to the fluid outlet, and is operable when rotated into a defined second position to block the primary flow path on an upstream side of the ball, while simultaneously establishing a secondary flow path that is more restrictive than the primary flow path. The ball in its second position establishes the secondary flow path by placing the fluid outlet in fluid communication with a valve chamber surrounding the ball, where the secondary flow path further including one or more secondary fluid passageways within the ball valve assembly that place the fluid inlet in fluid communication with the valve chamber and are open irrespective of the position of the ball. 
         [0006]    With the arrangement immediately above, it will be understood that the one or more secondary fluid passageways supply fluid to the valve chamber irrespective of the rotational position of the ball. However, the ball seals the valve chamber from the fluid outlet unless the ball occupies its defined second position. In that second position, the ball  34  ducts fluid from the valve chamber to the fluid outlet. In the same or in another example embodiment, the ball valve assembly further defines a third position for the ball, where no flow path exists through the ball valve assembly. Thus, in the first position, fluid flows directly from the fluid inlet of the ball valve assembly to the fluid outlet of the ball valve assembly—it will be understood that this flow pass through the ball. However, in the second position, fluid flows from the fluid inlet and into the valve chamber via the one or more secondary fluid passageways—which can be understood as intentional leakage paths—and from there through the ball and on into the fluid outlet of the ball valve assembly. Also in this context, rotation of the ball into a defined third position operates as a shutoff position by blocking any fluid from reaching the fluid outlet. 
         [0007]    In a more detailed example applicable to the same or another embodiment, the ball valve assembly comprises a housing having an inlet coupling section, an outlet coupling section, and a valve section therebetween. The valve section defines a valve chamber, the inlet coupling section defines an inlet chamber, and the outlet coupling section defines an outlet chamber. An inlet port opens from the inlet chamber into the valve chamber through an inlet ball seat and a corresponding outlet port opens from the valve chamber into the outlet chamber through an outlet ball seat, while a ball is rotatably carried within the valve chamber and sealingly engaged between the inlet and outlet ball seats. 
         [0008]    When the ball is rotated into a defined first position, a first bore through the ball places the inlet chamber in fluid communication with the outlet chamber, and, when the ball is rotated into a defined second position, the first bore is open to the valve chamber, the ball blocks the inlet ball seat, and a second bore in the ball places the outlet chamber in fluid communication with the valve chamber via the first bore. Correspondingly, a secondary fluid passageway bypasses the ball and places the inlet chamber in fluid communication with the valve chamber, thereby forming, in conjunction with valve chamber and the first and second bores, a restricted or secondary flow path from the inlet chamber to the outlet chamber that is operative when the ball occupies the second position. 
         [0009]    The ball valve assembly may further define a third position for the ball, wherein all flow through the ball valve assembly is cutoff. Consequently, the ball valve assembly in such embodiments may be understood as providing three defined positions for the ball: a first or open position that provides for a “normal” or “regular” flow through the ball valve assembly, a second or trickle position that provides for a “restricted” or “trickle” flow through the ball valve assembly, and a third or closed position that prevents any flow through the ball valve assembly. By way of non-limiting example, the trickle flow is a restricted flow in the sense that, under the same head conditions, the trickle flow rate is no more than a tenth the normal flow, and may be considerably less, according to design preferences. 
         [0010]    In the same or in another example embodiment, a ball valve assembly comprises a housing defining an interior valve chamber housing a ball that is rotatably seated between an inlet ball seat opening towards an upstream fluid inlet of the ball valve assembly and an outlet ball seat opening towards a downstream fluid outlet of the ball valve assembly. In a first position the ball ducts fluid from the fluid inlet to the fluid outlet, and in a second position the ball blocks the inlet ball seat and ducts fluid from the valve chamber to the fluid outlet. Correspondingly, the ball valve assembly includes a bypass or secondary fluid passageway that bypasses the ball and supplies fluid from the fluid inlet to the valve chamber, for ducting by the ball from the valve chamber to the fluid outlet when the ball is in the second position. 
         [0011]    Of course, the present invention is not limited to the above features and advantages. Those of ordinary skill in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a cross-sectional side view of one embodiment of a ball valve assembly. 
           [0013]      FIG. 2  is a top view of the ball valve assembly. 
           [0014]      FIG. 3  is an exploded view of the ball valve assembly. 
           [0015]      FIG. 4  is an end view of an inlet end of the ball valve assembly. 
           [0016]      FIG. 5  is an end view of an outlet end of the ball valve assembly. 
           [0017]      FIG. 6  is a perspective front-side view of the ball valve assembly. 
           [0018]      FIG. 7  is a perspective back-side view of the ball valve assembly. 
           [0019]      FIG. 8  is a perspective view of one embodiment of a ball, for use in the ball valve assembly. 
           [0020]      FIG. 9  is a cross-sectional top view of the ball valve assembly, where the ball of  FIG. 8  is rotated into a first position associated with a primary flow path through the ball valve assembly. 
           [0021]      FIG. 10  is a cross-sectional top view of the ball valve assembly, where the ball of  FIG. 8  is rotated into a second position associated with a secondary flow path through the ball valve assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]      FIG. 1  is a cross-sectional side view of a ball valve assembly  10  according to an example embodiment and  FIG. 2  is a top view of the same assembly. The cut line A-A depicted in  FIG. 2  corresponds to the cross-sectional view of  FIG. 1 . 
         [0023]    With reference to both figures, the ball valve assembly  10  comprises a housing  12  having an inlet coupling section  14 , an outlet coupling section  16 , and a valve section  18  therebetween. The inlet and outlet coupling sections  14  and  16  are configured, for example, for making up connections with upstream and downstream piping. 
         [0024]    The valve section  18  defines a valve chamber  20 , the inlet coupling section  14  defines an inlet chamber  22  and the outlet coupling section  16  defines an outlet chamber  24 . An inlet port  26  opens from the inlet chamber  22  into the valve chamber  20  through an inlet ball seat  28  and a corresponding outlet port  30  opens from the valve chamber  20  into the outlet chamber  24  through an outlet ball seat  32 . 
         [0025]    A ball  34  is rotatably carried within the valve chamber  20  and is sealingly engaged between the inlet and outlet ball seats  28  and  32 . The ball  34  is connected to a valve stem  36  that projects through the housing  12  and provides a mechanism for maintaining or otherwise fixing the ball  34  in position within the valve chamber  20  in sealing engagement with the inlet and outlet ball seats  28  and  32 . The valve stem  36  is rotatable and thus provides an external mechanism by which the ball  34  is rotated, either manually or by machine control. 
         [0026]    Water or another fluid passing through the ball valve assembly  10  enters via a fluid inlet  38  of the ball valve assembly  10  and exits through a fluid outlet  40  of the ball valve assembly. When the ball  34  is rotated into a first position, a first bore  42  through the ball  34  places the inlet chamber  22  in fluid communication with the outlet chamber  24 . When the ball  34  is rotated into a second position, the first bore  42  is open to the valve chamber  20 , the ball  34  blocks the inlet ball seat  28 , and a second bore  44  in the ball  34  places the outlet chamber  24  in fluid communication with the valve chamber  20  via the first bore  42 . 
         [0027]    In saying that the ball  34  “blocks” the inlet ball seat  28 , the reader will understand that an un-bored or closed surface portion of the ball  34  will be turned into an upstream-facing position when the ball  34  is rotated into the second position, and that closed ball face will be sealed against the inlet ball seat  28  and will thus block the interior bore of the inlet ball seat  28 . Later diagrams provide a more detailed depiction of this arrangement. 
         [0028]    However, despite the ball  34  blocking the normal fluid flow path through the inlet ball seat  28  when rotated into its second position, a secondary fluid passageway  50  bypasses the ball  34  and places the inlet chamber  22  in fluid communication with the valve chamber  20 . This arrangement, in conjunction with the valve chamber  20  and the first and second bores  42  and  44  of the ball  34  as they are oriented when the ball  34  is in the second position, form a restricted or secondary flow path from the inlet chamber  22  to the outlet chamber  24  that is operative when the ball  34  occupies the second position. 
         [0029]    A better understanding of the secondary fluid passageway  50  is gained with reference to  FIG. 1 , where two such secondary fluid passageways are shown as  50 - 1  and  50 - 2 . In the illustrated example, the two secondary fluid passageways  50 - 1  and  50 - 2  are formed within the body of the housing  12 , e.g., either by machining, molding or extruding the housing  12  to include such passageways. Critically, these secondary fluid passageways  50 - 1  and  50 - 2  are open independent of the rotation of the ball  34 ; that is, they are not blocked even when the ball  34  is rotated into its second position, which places the first bore  42  of the ball  34  crosswise with respect to the normal flow path and blocks the inlet ball seat  28 . 
         [0030]    The reference number  50  shall be used without suffixing, for generic reference to a single secondary fluid passageway, and for generically referencing any number of secondary fluid passageways. Further, it shall be understood that this disclosure contemplates embodiments of the ball valve assembly  10  that include a single secondary fluid passageway  50 , or two or more secondary fluid passageways  50 . A secondary fluid passageway  50  may be formed or machined in the housing  12  or in the inlet ball seat  28 . In the latter case, it will be understood that the inlet ball seat  28  is purposefully constructed to be “leaky” according to some desired restricted flow rate and that, although the ball  34  is still operable to seal the main pathway through the inlet ball seat  28 , one or more secondary fluid passageways  50  are formed within the inlet ball seat  28 , to allow the fluid to flow around or past the ball  34  when the ball is in its trickle position, and into the valve chamber  20 , albeit at a much restricted flow rate. 
         [0031]    In one or more embodiments, there is a plurality of secondary fluid passageways  50 , and the aggregate cross-sectional area of the plurality of secondary fluid passageways  50  is equal to or greater than the cross-sectional area of the second bore  44  in the ball. For example, in the exploded view of  FIG. 3 , one sees that an inlet ring section  60  may be used to define the inlet chamber  22 —i.e., to separate the inlet chamber  22  from the valve chamber  20 —and to couple with the inlet ball seat  28  on the upstream side. 
         [0032]    The inlet ring section  60  in the depicted embodiment includes a number of upstream openings  62 , e.g.,  62 - 1  and  62 - 2 , in an inlet face  63  of the inlet ring section  60 . The inlet face  63  faces upstream and the plurality of upstream openings  62  are distributed in the inlet face  63  around the inlet port  26 , which is defined within the inlet face  63 . While the secondary fluid passageways  50  are not visible in  FIG. 3 , the reader will appreciate that each upstream opening  62  serves as an inlet into a corresponding secondary fluid passageway  50 , for ducting fluid from the inlet chamber  22  into the valve chamber  20 . 
         [0033]    The upstream openings  62  in the inlet ring section  60  are not needed in embodiments where the secondary fluid passageway(s)  50  are formed within the inlet ball seat  28 , such that the inlet ball seat  28  provides controlled leakage around the ball  34 . In at least one such embodiment, there is a potentially large plurality of secondary fluid passageways  50 , as the inlet ball seat  28  is formed from a porous material, such as from POREX brand porous PTFE or another porous material suitable for use as a ball valve seat. 
         [0034]    As seen in  FIG. 3 , the inlet ball seat  28  has a generally ring or cylindrical shape and may couple to the inlet ring section  60  via a gasket  64 . A similar gasket or sealing ring  66  may be used on the outlet ball seat  32 . 
         [0035]      FIG. 3  also illustrates example details for the ball  34 , including a valve stem slot  68 , which is engaged by a the valve stem key  70  that projects from a bottom end of the valve stem  36 . The overall valve stem assembly  72  includes a top portion  74  that is engaged by an electro-mechanical drive system—not shown—for rotation of the ball  34 , along with various washers  76 ,  78 ,  80  and  82 . The valve stem assembly  72  projects through an opening  84  in the housing  12  of the ball valve assembly  10 , for engaging the ball  34  and retaining the ball  34  in position with the valve chamber  20 —i.e., the valve stem assembly  72  passes through the housing  12  and retains the ball  34  in a floating, rotatable engagement with the inlet and outlet ball seats  28  and  32 . 
         [0036]    Also as seen in  FIG. 3 , the inlet ball seat  28  has a bore or inner barrel that opens at one end, the upstream end, towards the inlet chamber  22  of the ball valve assembly  10 . The inlet ball seat bore opens at the downstream side towards the valve chamber  20 . When the ball  34  is rotated into its first or open position, the first bore  42  aligns with the bore of the inlet ball seat  28  and thus provides a continuous fluid pathway into the outlet chamber  24 . When the ball  34  is rotated into its defined second position, the first bore  42  is rotated out of alignment with the inlet and outlet ball seat bores, and a closed, un-bored surface of the ball  34  blocks the downstream bore opening of the inlet ball seat  28 . Correspondingly, the second bore  44  is rotated into alignment with the outlet ball seat  32 . 
         [0037]    Thus, when the ball  34  is rotated into its second position, the ends of the first bore  42  of the ball  34  opens into the valve chamber  20 , and the second bore  44  opens into the outlet chamber  24  through the outlet ball seat  32 . Here, it will be appreciated that the first bore  42  of the ball  34  runs diametrically through the ball  34  and the second bore  44  of the ball  34  is perpendicular to the first bore  42 . The second bore  44  opens at one end  46  into the exterior of the ball  34  and at the other end  48  into the interior wall of the first bore  42 . When the ball  34  is rotated substantially ninety degrees around an axis of rotation, it is moved from its first, open position to its second, trickle or leakage position. In the second position, the end  46  of the second bore  44  aligns with the bore of the outlet ball set  32  and the ends of the first bore  42  are open to the valve chamber  20 . 
         [0038]    Thus, the first bore  42  through the ball  34  can be understood as forming part of a primary flow path through the ball valve assembly  10  when it is rotated into alignment with the inlet and outlet ports  26  and  30  of the ball valve assembly  10 . Conversely, when the first bore  42  is rotated crosswise to the primary flow path, its respective ends open into the valve chamber  20 , and allow fluid to flow from the valve chamber  20  into the first bore  42  and further through the second bore  44 , which aligns with the outlet port  30  when the ball  34  occupies the second position. 
         [0039]    This functionality may be better appreciated with respect to the various views provided in  FIGS. 4-8 . In particular,  FIGS. 4 and 5  illustrate upstream and downstream ends of the ball valve assembly  10 ,  FIGS. 6 and 7  illustrate perspective front-quarter and rear-quarter views of the ball valve assembly  10 , and  FIG. 8  illustrates the ball  34  in closer detail. 
         [0040]    One sees that the first bore  42  in an end-to-end sense forms part of the primary flow path, denoted as flow path  1 . The first bore  42  also forms a part of the secondary flow path, denoted as flow path  2 .  FIG. 9  provides a cross-sectional plan view of the ball valve assembly  10  and relates these ball details to the overall assembly  10 . In particular,  FIG. 9  depicts the ball  34  rotated into the first position such that a primary flow path  90  is established from the fluid inlet  38  of the overall ball valve assembly  10  to the fluid outlet  40  of the overall ball valve assembly  10 . The primary flow path  90  is completed by rotating the first bore  42  of the ball  34  into alignment with the assembly inlet  38  and outlet  40 . 
         [0041]      FIG. 10  provides the same view but where the ball  34  is rotated into the second position, with the first bore  42  now positioned perpendicular to the direction of flow through the inlet  38  and outlet  40 , and with the second bore  44  aligned with the outlet  40 . This position of the ball  34  establishes a secondary flow path  92  from the inlet  38  to the outlet  40 , where the fluid flows through the one or more secondary fluid passageways  50 , into the valve chamber  20 , through the ends of the first bore  42 , which open into the valve chamber  20 , and through the second bore  44 . The second bore  44  opens through the outlet ball seat  32  into the outlet chamber  24 . 
         [0042]    Of course, the details of  FIGS. 9 and 10  should be understood as exemplary and not limiting. Broadly, in one or more embodiments contemplated herein, a ball valve assembly  10  has a primary flow path  90  running from a fluid inlet  38  of the ball valve assembly  10  to a fluid outlet  40  of the ball valve assembly  10 . A ball  34  disposed within the primary flow path  90  is operable when rotated into a first position to duct fluid from the fluid inlet  38  to the fluid outlet  40 , and is operable when rotated into a second position to block the primary flow path  90  on an upstream side of the ball  34  while simultaneously placing the fluid outlet  40  in fluid communication with a valve chamber  20  surrounding the ball  34 . 
         [0043]    The ball valve assembly  10  further provides or defines a secondary flow  92  path that is more restrictive than the primary flow path  90  and formed by the ball  34  in its second position and one or more secondary fluid passageways  50  that place the fluid inlet  38  in fluid communication with the valve chamber  20 . These secondary fluid passageways  50  are open irrespective of the position of the ball  34 , and thus provide a leakage path around the ball  34  in its trickle position. Of course, the rated flow rate of the secondary flow path  92  may be much less than that of the primary flow path  90 . That is, the ball valve assembly  10  can be configured via proper sizing of the second bore  44  and the secondary fluid passageways  50  to provide a secondary-path maximum flow rate that is one-tenth or less, e.g., one-fiftieth, of the maximum flow rate of the primary flow path  90 . 
         [0044]    With the above details in mind, according to the teachings herein a ball valve assembly  10  comprises a housing  12  defining an interior valve chamber  20  housing a ball  34  rotatably seated between an inlet ball seat  28  opening towards an upstream fluid inlet  38  of the ball valve assembly  10  and an outlet ball seat  32  opening towards a downstream fluid outlet  40  of the ball valve assembly  10 . In a first position, the ball  34  ducts fluid from the fluid inlet  38  to the fluid outlet  40 . In a second position, the ball  34  blocks the inlet ball seat  28  and ducts fluid from the valve chamber  20  to the fluid outlet  40 . Correspondingly, the ball valve assembly  10  includes a secondary fluid passageway  50  that bypasses the ball  34  and supplies fluid from the fluid inlet  38  to the valve chamber  20 , for ducting by the ball  34  from the valve chamber  20  to the fluid outlet  40  when the ball  34  is in the second position. 
         [0045]    Also, as noted, the ball valve assembly  10  may define or otherwise provide for rotation of the ball  34  into a third position, where the ball valve assembly  10  is closed and prevents all flow through it. For example, with reference to  FIGS. 3 and 8 , the ball  34  in its third position will have the second bore  44  facing the inlet ball seat  28 , which in turn causes the diametrically opposite, closed surface of the ball  34  to seal off the outlet ball seat  32 . That is, when the ball  34  occupies the third position, the outlet ball seat  32  is not open to the inlet ball seat  28  via the first bore  42  of the ball  34 , nor is the outlet ball seat  32  open to the valve chamber  20  via the combination of first and second bores  42  and  44  of the ball  34 . 
         [0046]    Thus, the first position of the ball  34  provides for a maximum flow rate through the ball valve assembly  10 , the second position of the ball  34  provides for a restricted flow rate through the ball valve assembly  10 , e.g., essentially a trickle flow, and the third position of the ball  34  provides a traditional closed or shut-off position. In one or more embodiments, the valve stem assembly  72  includes detents or other mechanical features that define the first, second and third ball positions, or that otherwise provide for positive engagement of the defined ball positions. 
         [0047]    Moreover, the exterior of the housing  12  in one or more embodiments is inscribed or otherwise labeled with indicia indicating the defined ball positions. In this regard, while it may be possible in some embodiments to position or leave the ball  34  in a rotational position between defined positions, the ball valve assembly  10  is not designed for operation in any such undefined position. Correspondingly, it will be understood that the ball valve assembly  10  provides the designed—for regular flow and the designed—for trickle flow when the ball  34  occupies the first or second positions, respectively. 
         [0048]    Notably, modifications and other embodiments of the disclosed invention(s) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention(s) is/are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.