Patent Publication Number: US-2011073792-A1

Title: Hemispherical Wedge Valve with Laminar Flow

Description:
This application claims priority to provisional application Ser. No. 61/245,896 filed on Sep. 28, 2009 
    
    
     BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention generally relates to an improved valve of the hemi-wedge type for use in the control of fluids in a pipeline. The valve of the present invention is particularly useful in providing both a tight shutoff of fluids when closed, a high flow when open, and includes a device for providing laminar flow through the valve body when in the open position. 
     2. Description of Related Art 
     Ball valves, plug, valves, and the like are well known to those skilled in the art. A common characteristic of these valves is that they may be moved from a full open position to a full closed position through an angle of no more than about ninety (90) degrees. 
     A simple ball valve comprises a rotatable ball having a bore therethrough corresponding to the fluid flow path, together with a seat for sealing with the ball surface. Ball valves permit fluid flow to be fully stopped by rotating the ball not more than about ninety (90) degrees. However, these valves offer only minimal graduated control of the fluid flow achieved by setting the ball at intermediate positions. Further, these valves are placed in the open or close position without a mechanical force applied by the closure member against a seat. 
     A simple plug valve comprises a rotatable tapered plug having a bore therethrough disposed in a complementary housing. The plug permits flow to be fully stopped by rotating the plug more than about ninety (90) degrees. Plug valves operate similarly to the previously described ball valve and offer similar advantages and disadvantages. 
     Gate valves, globe valves and the like are also well known to those skilled in the art. A common characteristic of these valves is that they may be moved from a full open position to a full closed position by the rising and lowering of a valve stem acting on a closure member (gate in a gate valve or disc or plug in a globe valve). These valves offer sealing advantages over ball valves, but take longer to open or close and generally have a higher leakage of fluid to the atmosphere with the rising and lowering of the stem. 
     A valve offering significant advantages over conventional ball, plug, gate, and globe valves is the hemi-wedge valve described in U.S. Pat. No. 4,962,911, and improved with a valve driver in U.S. Pat. No. 5,333,834, and improved with a cartridge feature for quick and easy repair in U.S. Pat. No. 7,484,523. The contents of these three patents are expressly incorporate herein by reference thereto. The hemi-wedge valve includes a curved wedge comprising a tapered, spherical section rotatable through the fluid path and cooperating with a complementary curved seat to affect a shut off. An important feature of the hemi-wedge valve is that the thickness of the wedge increases from its leading end to its trailing end. The wedge includes a round bore forming a part of the fluid path through its thinner, leading end. The wedge is solid and thicker at its trailing end. Rotation of the hemi-wedge through about ninety (90) degrees into the fluid path closes the fluid path by blocking it with the solid and thicker end of the wedge. This provides a mechanical loading of the seat. 
     A shortcoming of the existing designs is that they do not provide a mechanism for establishing and maintaining laminar flow of the fluid through the valve when the valve is in the open position. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to a mechanism for insuring that the flow through a hemi-wedge type valve remains laminar. Non-laminar flow can result in excessive noise, structural failure, erosion, cavitation, and premature wearing of valve seals and seats. In one embodiment laminar flow is accomplished by forming the core of the hemi wedge as a solid member having a plurality of parallel flowpaths throughout its length. Other embodiments are disclosed. 
     This divides the flow of the fluid at the inlet of the valve into a plurality of parallel flow paths which eliminates turbulence in the main flowpath and results in laminar flow through the valve body. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  is a cross sectional view of a typical hemi-wedge valve. 
         FIG. 2  is a perspective view of a valve core body for a hemi-wedge valve according to one embodiment of the invention. 
         FIG. 3  is a cross sectional view of the valve core body of  FIG. 2   
         FIG. 4  is a front view of a second embodiment of the laminar flow device. 
         FIG. 5  is a front view of another embodiment of the laminar flow device. 
         FIG. 6  is a front view of a further embodiment of the laminar flow device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a hemi-wedge valve  20  is shown including an inlet  2 , a core section comprising two cylindrical hollow body members  4 ,  5 , and an outlet  3 . A hemi-wedge valve element  7  is rotatably mounted in the valve  20 . The thickness of the hemi wedge valve element increases from the leading edge to the trailing edge which results in an improved seal. The operation of the wedge is described in detail in U.S. Pat. No. 4,962,911, the contents of which is expressly incorporated herein by reference thereto. In order to maintain laminar flow, a solid valve core member  4  as shown in  FIG. 2  that includes a plurality of separate flow paths  70  is provided. The valve also includes various seals  16 ,  53 ,  12 ,  10 . Core member  5  includes a first cylindrical portion  51 , a first shoulder  59  and a second cylindrical portion  52  that receive complimentary shaped portions on the core member  4 . Hemi-wedge valve element  7  includes inner and outer curved surfaces  31  and  30 . A downstream valve seat  8  holds seal  10 . The particular arrangement of the hemi-wedge valve shown in  FIG. 1  results in a dual valve seat arrangement that includes inner and outer surfaces  31  and  30  and seals  12  and  10  respectively. 
     While the valve core may consist of two separate elements as shown in  FIG. 1 , the valve core may be a unitary piece as shown in the above mentioned U.S. Pat. No. 4,962,911. This invention is suitable for use in the various designs of hemi wedge valves of the prior art that utilize a core member. Other laminar flow techniques may be used such as shown in  FIGS. 4-6 . 
     In  FIG. 4  the parallel flow paths  60  are formed by a plurality of axially extending baffles  61  and  62  that intersect at right angles. The baffles could be either vertically or horizontally extending or both as shown. 
       FIG. 5  discloses another embodiment of the laminar flow device. In this embodiment, the core member is provided with a plurality of axially and radially extending baffles  71  that form separate flow paths  72 . 
     In  FIG. 6 , parallel flow paths  82  are formed by a plurality of discrete flow tubes  81  positioned within the core member. 
       FIG. 6  discloses a further embodiment wherein a plurality of axially extending tubes  81  are located within the core member  4  thereby forming a plurality of parallel passages  82 . 
     The parallel flow passages could extend for the entire length of core members  4 ,  5  or only through a portion thereof. Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent they are included in the accompanying claims.