Abstract:
Duplex fluid strainers, systems and methods are provided, and include a housing with a first valve chamber defining an inlet port, a first port, and a second port, and a second valve chamber defining a third port, a fourth port, and an outlet port. The first and third ports communicate with a first strainer chamber, and the second and fourth ports communicate with a second strainer. A first seal assembly includes a first disk movable within the first valve chamber into sealing engagement against either of the first port or the second port, and a second seal assembly includes a second disk movable within the second valve chamber into sealing engagement against either of the third port or the fourth port.

Description:
RELATED APPLICATIONS 
     The presently disclosed subject matter claims the benefit of U.S. Patent Application Ser. No. 61/360,620, filed Jul. 1, 2010, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The subject matter disclosed herein relates generally to a fluid strainer for use in a fluid piping system. More particularly, the subject matter disclosed herein relates to duplex strainer apparatuses, systems and methods for providing multiple straining flow paths. 
     BACKGROUND 
     In many fluid flow applications, it is often necessary that the flow from an upstream source be cleaned or strained before use in downstream components. In this regard, strainers are used to protect such downstream equipment by mechanically removing solids from flowing fluids via a straining element, such as a perforated, mesh, or wedge-wire straining element. Although many designs and configurations of strainers exist, duplex strainers provide an added advantage over other straining systems by permitting continuous straining and cleaning of a flow. Specifically, duplex strainers generally include two strainer chambers and some type of mechanism for diverting the flow from one chamber to the other to isolate the flow to a single chamber. This arrangement permits cleaning, servicing, or repairing of one chamber while the other one is in use, thereby enabling the flow through the duplex strainer to remain substantially continuous. 
     A number of different designs for duplex strainers have been used, with varying valve designs (e.g., scotch yokes, ball valves) for switching the flow between strainers, but each design both has advantages over other options and suffers from one or more problems, such as number and complexity of components, space requirements, effectiveness in flow isolation, and/or ease of operation. Accordingly, an improved duplex strainer is desirable, for example one with a design to effectively control the flow between and among multiple strainer assemblies while minimizing the problems found in prior art designs. 
     SUMMARY 
     In accordance with this disclosure, novel apparatuses, systems and methods are provided for fluid straining for use in a fluid piping system. In one aspect, a fluid strainer is provided. The fluid strainer can comprise a housing comprising a first valve chamber comprising an inlet port, a first port, and a second port, and a second valve chamber comprising a third port, a fourth port, and an outlet port. A first strainer chamber can comprise a first strainer inlet in communication with the first port and a first strainer outlet in communication with the third port, and a second strainer chamber can comprise a second strainer inlet in communication with the second port and a second strainer outlet in communication with the fourth port. Within the first valve chamber, a first seal assembly can comprise a first pivotable member, a first disk, and a first coupler connecting the first pivotable member to the first disk such that the first pivotable member is movable to cause the first disk to move within the first valve chamber into sealing engagement against either of the first port or the second port. Similarly, within the second valve chamber, a second seal assembly can comprise a second pivotable member, a second disk, and a second coupler connecting the second pivotable member to the second disk such that the second pivotable member is movable to cause the second disk to move within the second valve chamber into, sealing engagement against either of the third port or the fourth port. 
     Although an aspect of the subject matter disclosed herein has been stated hereinabove, and which is achieved in whole or in part by the presently disclosed subject matter, other aspects will become evident as the description proceeds when taken in connection with the accompanying drawings as best described hereinbelow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of the present subject matter will be more readily understood from the following detailed description which should be read in conjunction with the accompanying drawings that are given merely by way of explanatory and non-limiting example, and in which: 
         FIG. 1  is a perspective cutaway view of a duplex fluid strainer according to an embodiment of the presently disclosed subject matter; 
         FIG. 2  is a side sectional view of a housing of a duplex fluid strainer according to an embodiment of the presently disclosed subject matter; and 
         FIGS. 3A and 3B  are top sectional views of a duplex fluid strainer according to two embodiments of the presently disclosed subject matter. 
     
    
    
     DETAILED DESCRIPTION 
     The present subject matter provides devices for fluid straining for use in a fluid piping system. In one aspect, the present subject matter provides a fluid strainer, generally designated  100 . As shown in  FIGS. 1 and 2 , fluid strainer  100  can comprise a housing  110 , which can itself comprise a first valve chamber  112  defining a strainer inlet  114  and a second valve chamber  116  defining a strainer outlet  118 . Fluid strainer  100  can be installed in-line with a fluid piping system such that fluid is received from an upstream piping element at strainer inlet  114  and passed to a downstream piping element out of strainer outlet  118 . 
     In addition, strainer  100  can further include a first strainer chamber  210  and a second strainer chamber  220 , each in communication with both of first valve chamber  112  and second valve chamber  116 , and each containing a removable strainer basket or filter therein for straining and cleaning the material which flows therethrough. Each of housing  110 , first strainer chamber  210 , and second strainer chamber  220  can be composed of a cast iron material, stainless steel, bronze, or any other material determined to be appropriate for the particular fluid piping system. First strainer chamber  210  and second strainer chamber  220  can each be secured to housing  110  using any of a variety of fasteners, including but not limited to studs, bolts, or clamps. One or both of first strainer chamber  210  or second strainer chamber  220  can be detachable from housing  110 , which can allow easy access for cleaning, repair, or any other maintenance procedure. 
     In this configuration, fluid received by first valve chamber  112  through strainer inlet  114  can be passed to either or both of first strainer chamber  210  or second strainer chamber  220 , entrained solids or other undesirable materials can be removed from the fluid within first or second strainer chambers  210  or  220 , the fluid can be passed from the strainer chambers to second valve chamber  116 , and the fluid can be discharged from second valve chamber  116  through strainer outlet  118 . 
     In particular, in addition to strainer inlet  114 , first valve chamber  112  can further define a first port  121  and a second port  122 . In the configuration shown in  FIG. 1 , for example, first port  121  and second port  122  can be positioned on opposite sides of first valve chamber  112 . Each of first port  121  and second port  122  can serve as fluid pathways out of first valve chamber  112  (e.g., toward first strainer chamber  210  or second strainer chamber  220 , respectively). For instance, first strainer chamber  210  can comprise a first strainer inlet  212  in communication with first port  121 , whereas second strainer chamber  220  can comprise a second strainer inlet  222  in communication with second port  122 . In this arrangement, fluid received by first valve chamber  112  through strainer inlet  114  can be directed through either or both of first port  121  or second port  122  for directing fluid to one or both of first or second strainer chambers  210  or  220 , respectively. 
     Likewise, second valve chamber  116  can define a third port  123  and a fourth port  124 , which can be positioned on opposing sides of second valve chamber  116  and can each serve to admit fluid into second valve chamber  116  (e.g., from first strainer chamber  210  or second strainer chamber  220 , respectively). For instance, first strainer chamber  210  can comprise a first strainer outlet  214  in communication with third port  123 , and second strainer chamber  220  can comprise a second strainer outlet  224  in communication with fourth port  124 . In this arrangement, fluid from either or both of first or second strainer chambers  210  or  220  can be directed to second valve chamber  116  through third and fourth ports  123  or  124 , respectively, for directing fluid to second valve chamber  116  and out of fluid strainer  100  through strainer outlet  118 . 
     Regarding the particular design of fluid strainer  100 ,  FIG. 1  shows a cutaway front view of fluid strainer  100 . As shown in  FIG. 1 , fluid strainer  100  can comprise a movable flow control system within housing  110  to selectively control the flow of fluid to either or both of first or second strainer chambers  210  or  220 . Specifically, for example, the flow control system can comprise a first disk  130  movable within first valve chamber  112  into sealing engagement against either of first port  121  or second port  122 . First disk  130  can be sufficiently sized so that it is capable of closing off flow when moved against either of first port  121  or second port  122 . In this regard, first disk  130  can include sealing elements, such as O-rings formed from an elastomeric material (e.g., rubber), which can help first disk  130  to form a fluid-tight seal with first port  121  or second port  122 . 
     To help guide the movement of first disk  130  within first valve chamber  112 , first disk  130  can be connected to a first disk stem  132  that extends away from one side of first disk  130  towards first port  121 . First disk stem  132  can be received by a first disk guide  134  positioned within first port  121 . Similarly, first disk  130  can be further connected to a second disk stem  136  that extends away from the other side of first disk  130  towards second port  122 . Second disk stem  136  can be received by a second disk guide  138  positioned within second port  122 . In this arrangement, first disk  130  can be slideably supported for reciprocal lateral movement in first valve chamber  112 . 
     Similarly, a second disk  140  can be movable within second valve chamber  116  into sealing engagement against either of third port  123  or fourth port  124 . Again, second disk  140  can be sized to substantially block flow to either of third port  123  or fourth port  124 , and second disk  140  can further include sealing elements (e.g., O-rings) for helping to establish a fluid-tight seal. Second disk  140  can be connected to a third disk stem  142  and a fourth disk stem  146  extending away from opposing sides of second disk  140  towards a third disk guide  144  positioned in third port  123  and a fourth disk guide  148  positioned in fourth port  124 , respectively. In this arrangement, second disk  140  can be slideably supported for reciprocal lateral movement in second valve chamber  116 . 
     Movement of first disk  130  and second disk  140  can be controlled by a single pivotable coupling rod  150  that can, for example and without limitation, extend through both of first valve chamber  112  and second valve chamber  116 . Specifically, within first valve chamber  112 , at least one first coupler can be mounted to coupling rod  150  and can extend toward first disk  130 . In the configuration shown in  FIGS. 1, 2, 3A, and 3B , for example, the at least one first coupler can comprise a top first coupler  152   a  and a bottom first coupler  152   b , which can each comprise a Scotch yoke extending from coupling rod  150  towards an exterior edge of first disk  130 . Referring to  FIG. 2 , top first coupler  152   a  can extend from coupling rod  150  towards a first pin  154   a  connected at a top edge of first disk  130 , and bottom first coupler  152   b  can extend from coupling rod  150  towards a second pin  154   b  connected at a bottom edge of first disk  130 . Each of top first coupler  152   a  and bottom first coupler  152   b  can define a substantially forked end that is adapted to capture first pin  154   a  and second pin  154   b , respectively. 
     Likewise, within second valve chamber  116 , at least one second coupler can be mounted to coupling rod  150  and can extend toward second disk  140 . For example, the at least one second coupler can comprise a top second coupler  156   a  and a bottom first coupler  156   b , which can each comprise a Scotch yoke extending from coupling rod  150  towards second disk  140 . Specifically, top second coupler  156   a  can extend towards a third pin  158   a  connected at a top edge of second disk  140 , and bottom second coupler  156   b  can extend from coupling rod  150  towards a fourth pin  158   b  connected at a bottom edge of second disk  140 . 
     In this arrangement, when coupling rod  150  is rotated, the rotation can be transferred by first couplers  152   a  and  152   b  and second couplers  156   a  and  156   b  into linear sliding displacement of both first disk  130  and second disk  140 . For example, coupling rod  150  can be rotated to a first sealing position in which first disk  130  is moved into sealing engagement against first port  121  of first strainer chamber  112 , and second disk  140  is moved into sealing engagement against third port  123  of second strainer chamber  116 . This arrangement is shown generally in  FIG. 3A . As shown in  FIG. 3A , in this first sealing position, fluid entering first valve chamber  112  through strainer inlet  114  can be routed through second port  122  into second strainer chamber  220 , from which it can be further routed through fourth port  124  into second valve chamber  116 , where it can be discharged from strainer outlet  118 . Similarly,  FIG. 3B  shows first disk  130  moving towards this position in a version of fluid strainer  100  having two strainer baskets in each of first strainer chamber  210  and second strainer chamber  220 . Regardless of the specific configuration of fluid strainer  100 , however, the movement of first disk  130  and second disk  140  can be substantially the same. 
     Alternatively, coupling rod  150  can be rotated to move to a second sealing position in which first disk  130  is in sealing engagement against second port  122  at the same time that second disk  140  is in sealing engagement against fourth port  124 . In this arrangement, fluid entering first valve chamber  112  through strainer inlet  114  can be routed through first port  121 , first strainer chamber  210 , and third port  123  into second valve chamber  116 , where it can be discharged from strainer outlet  118 . 
     Finally, a number of additional features can further improve the operation of fluid strainer  100 . First, a pressure equalization line generally designated  160  can be connected between first strainer chamber  210  and second strainer chamber  220  for improving service life of seals within fluid strainer  100  and minimizing operating torque. Specifically, for instance, when coupling rod  150  is moved to the first sealing position (i.e., positioned for flow through second strainer chamber  220 ), fluid pressure in the system can tend to maintain first disk  130  and second disk  140  against first port  121  and third port  123 , respectively, making it difficult to move coupling rod  150  to the first sealing position or to a neutral position in between the first and second sealing positions. To alleviate this problem, pressure equalization line  160  can be operated to reduce or eliminate the pressure differential between the active fluid pathway (e.g., first valve chamber  112 , second strainer chamber  220 , and second valve chamber  116 ) and first strainer chamber  210 , thereby requiring less force to operate coupling rod  150 . 
     Another feature that can be advantageously included in fluid strainer  100  is a flow-smoothing mechanism to reduce turbulence within the fluid pathways of fluid strainer  100 . Specifically, fluid strainer  100  can comprise a plurality of flow routing vanes at least partially traversing one or more of first port  121 , second port  122 , third port  123 , or fourth port  124 . For example, referring again to  FIG. 1 , first port  121  can comprise a plurality of first flow routing vanes  171  positioned across the opening. First flow routing vanes  171  can be configured to alter incoming turbulent flow between first valve chamber  112  and first strainer chamber  210  to become smoother, thereby reducing pressure drop, noise, erosion, corrosion, vibration, and/or cavitations. Similarly, as shown in  FIG. 1 , one or more of second port  122 , third port  123 , and/or fourth port  124  can likewise comprise a plurality of second flow routing vanes  172 , third flow routing vanes  173 , and/or fourth flow routing vanes  174 , respectively, for smoothing the flow through those ports. 
     The present subject matter can be embodied in other forms without departure from the spirit and essential characteristics thereof. The embodiments described therefore are to be considered in all respects as illustrative and not restrictive. Although the present subject matter has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art are also within the scope of the present subject matter.