Patent Document

FIELD OF THE INVENTION 
   The present invention relates to a valve assembly for controlling fluid flow, and more particularly relates to a generally ball type valve which is rotatably mounted in a housing, for controlling fluid flow between open, closed and intermediate positions therethrough. 
   BACKGROUND OF THE INVENTION 
   For adjusting fluid flow, a wide variety of valve types are known. One type of valve is generally known as a ball valve. A ball valve has a plug or valve body mounted inside a valve housing. A bore or other passageway or passageways is provided through the valve body so that the valve body can be rotated between open, closed and intermediate flow positions. These valves sometimes face certain disadvantages however. For example, the pressure drop characteristic curve when plotted against the rotation of the valve body may have undesirably abrupt or sudden pressure changes. In some instances a more gradual pressure drop is desired. Also, commonly known valves are often subject to undesirable cavitation due to shape pressure transients or high speed flow around edges of the valve opening. 
   According, it would be desirable to have a fluid control valve that provides desirable characteristics and overcomes the above mentioned difficulties at least to some extent. 
   SUMMARY OF THE INVENTION 
   The foregoing needs are met, to a great extent, by the present invention, wherein in one aspect an apparatus and method is provided that in some embodiments provides a fluid control valve apparatus and method. 
   In accordance with one embodiment of the present invention a valve assembly comprises a housing having an inlet, an outlet, and an internal volume; a pair of sealing rings and mounted to the housing; and a valve body rotatably disposed within the housing for contact with the seating rings, the valve body comprising a generally spherical main body having a generally cylindrical bore therethrough; and a plurality of slotted plates longitudinally parallel to each other and parallel with the axis rotation of the valve body. 
   In accordance with another embodiment of the present invention a valve assembly comprises a housing having an inlet, an outlet, and an internal volume; sealing means mounted to the housing; and a valve body rotatably disposed within the housing for sealing contact with the sealing means, the valve body comprising a generally spherical main body having a generally cylindrical bore therethrough; and a plurality of slotted plates longitudinally parallel to each other and parallel with the axis of rotation of the valve body. 
   In accordance with yet another embodiment of the present invention a method of providing a valve assembly, having a housing having an inlet, an outlet, and an internal volume and a pair of sealing rings mounted to the housing comprises rotating a valve body rotatably disposed within the housing in contact with the sealing rings, the valve body comprising a generally spherical main body having a generally cylindrical bore therethrough; and a plurality of slotted plates longitudinally parallel to each other and parallel with the axis of rotation of the valve body. 
   In accordance with yet another embodiment of the present invention a valve body for use in a valve assembly having a housing having an inlet, an outlet, and an internal volume and a pair of sealing rings mounted to the housing and the valve body comprises a main body rotatably disposed within the housing for contact with the sealing rings, the main body comprising a generally spherical main body having a generally cylindrical bore therethrough; and a plurality of slotted plates longitudinally parallel to each other and parallel with the axis of rotation of the valve body. 
   There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
   In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
   As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of a valve assembly according to a preferred embodiment of the invention, taken through line  1 — 1  in  FIG. 4 , and showing the valve in a closed position. 
       FIG. 2  is a cross-sectional view similar to  FIG. 1 , taken through line  2 — 2  in  FIG. 5 , and showing the valve in an intermediate open position. 
       FIG. 3  is a cross-sectional view similar to  FIG. 1 , taken through line  3 — 3  in  FIG. 6 , and showing the valve in a fully open position. 
       FIG. 4  is an end view of a valve assembly in a closed position. 
       FIG. 5  is an end view of a valve assembly in an intermediate position. 
       FIG. 6  is an end view of a valve assembly in an open position. 
       FIG. 7  is a cross-sectional view taken through line  7 — 7  in  FIG. 4 , and showing a valve assembly in a closed position. 
       FIG. 8  is a cross-sectional view taken through line  8 — 8  in  FIG. 6 , and showing a valve in an open position. 
       FIG. 9  is a cross-sectional view of a valve body in accordance with a preferred embodiment of the present position. 
       FIG. 10  is a cross-sectional view of the valve body of  FIG. 9 . 
       FIG. 11  is an end view of the valve body of  FIG. 9 . 
       FIG. 12  is a top view of the valve body of  FIG. 9 . 
       FIG. 13  is a side view showing two slotted plates superimposed to each other. 
       FIG. 14  is an end view showing four slotted plates lying in parallel and spaced apart from each. 
       FIG. 15  is a plan view of a inner, larger, slotted plate. 
       FIG. 16  is a plan view of an outer, smaller, slotted plate 
   

   DETAILED DESCRIPTION 
   The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout.  FIGS. 1–3  are cross-sectional views of a valve assembly  10  according to a preferred embodiment of the invention, with  FIG. 1  showing the valve assembly  10  in a closed position,  FIG. 2  an intermediate open position, and  FIG. 3  a fully opened position. 
   The valve assembly  10  includes an outer housing  12  that includes a first fluid connection port  14  and an opposed second fluid connection port  16 . Because the valve assembly in this embodiment is symmetrical, either port  14  or port  16  can be the inlet and outlet ports, respectively. However, as an example  FIG. 3  illustrates an arrow showing a flow direction entering port  14  and exiting port  16 . 
   The valve assembly  10  also includes a rotatably mounted generally spherical plug assembly  20  which is shown in more detail in  FIGS. 9–11 . As seen in  FIGS. 9–11  the spherical plug assembly  20  includes a generally spherical main body  22  with an open central area that supports two larger inner slotted plates  24  and two somewhat shorter outer slotted plates  26 . Each of the plates  24  and  26  has a zig zag shape forming slots  25  and  27 , or alternatively has slots  25  and  27  cut therein. The main body  22  has a generally cylindrical bore  30  penetrating all the way therethrough, in which the plates  24  and  26  are mounted in parallel as shown. The generally cylindrical bore  30  also includes a tapered exit area  32  and an opposed and generally symmetrical tapered entrance area  34  as shown. The location of the plates  24  and  26  defines a number of flow channels or passages through the cylindrical bore  30 , including a center channel  40 , two intermediate channels  42 , and two outer channels  44 . Each of the outer channels  44  also open into one of the tapered entrances  32  and  34  respectively. The tapered entrances  32  and  34  are also noted as “v-slots”. 
   In addition to the above mentioned features,  FIGS. 10 and 11  show hinge post  50  and  52  which provide for rotatable mounting of the plug  20  in the housing  12  from  FIG. 1 .  FIG. 10  further illustrates a slot connection  54  for attaching the plug to a control stem that rotates the spherical plug assembly  20 . 
   A pair of sealing seats, which are capable of sealing contact with the valve body  20  are provided, as seen in  FIGS. 1–3 , with one seat  18  associated with the inlet port  14  and one seat  18  associated with the outlet port  16 . 
   The operation of the valve will now be described in more detail.  FIGS. 1 ,  4  and  7  show the valve in a completely closed orientation. In this orientation, the fluid passages  40 ,  42  and  44  are completely blocked from the inlet  14  and the outlet  16 . 
     FIGS. 2 and 5  show the valve in an intermediate position in which some flow is provided through the valve body  10 . From the inlet  14 , fluid will enter the tapered region  32 . Some fluid will flow through the various slots  25  and  27  thereby passing through each of the plates  24  and  26  until exiting through the tapered region  34 . In addition, because an annular space  60  is present around the body  20  in the corners of the valve housing surrounding the ball  20 , fluid can also move from one channel  40 ,  42  and  44  to another adjacent channel  40 ,  42  and  44 , and thus fluid that enters a channel  44  near the inlet  14  can also enter the other channels  40  and  42  and can exit out of the opposed channel  44  near the outlet end  16 . 
     FIGS. 3 ,  6 , and  8  illustrate the valve assembly  10  in a fully open configuration in which flow primarily passes directly through the channels  40 ,  42  and  44  from the inlet end  14  to the outlet end  16 . 
     FIG. 12  shows the plug assembly  20  from a different angle. 
     FIG. 13  is a plan view showing a plate  26  on top of a plate  24 .  FIG. 14  is an end view showing the arrangement of the plates  26  within the cylindrical bore of the plug.  FIGS. 15 and 16  are plan view of the large plate  24  and smaller plate  26  respectively. 
   The invention thus provides at least three mechanisms for gradually reducing pressure as the ball is rotated. First, the provision of the slots through the plates allows for damping of the pressure change. Second, the claims are exposed gradually as the valve is opened. Third, the tapered entrances  32  and  34  avoid sudden drops at the edge of the open and closed positions. 
   The arrangements described above can in some embodiments provide several advantages. First of all, it will be appreciated that the overall pressure drop occurs across six stages, two of them at the interaction of the balls with the seats, and four of them through the slots in the plates. The staged pressure drops has been found to desirably control cavitations and also provide desirable hydrodynamic noise attenuation properties compared to prior art devices. The use of the slots allows dimensions to be selected to pass large particles when dirty service with solid particles is needed. The illustrated embodiment is symmetrical and thus can be operated in bidirectional arrangements, when flow through the valve need to be reversed. The tapered v-slot provides better control for low flow conditions. It is also possible to install a mesh in the v-slots for cavitating liquid services with extremely high-pressure drops at low flow conditions. 
   Further, in the fully open position the plates occupy a relatively low amount of the flow cross-sectional area; in that the channels  40 ,  42  and  44  are wide and straight. Furthermore, the design can be at least to some extent self flushing, in that if a large piece of debris become blocked in a slot, when the valve if fully opened, the debris will tend to work itself from the slot and flow out through one of the channels  40 ,  42  and  44 , particularly when the channels have a larger cross-sectional area then the width of the slot. 
   When the valve is in the closed position it is completely shut off like a standard API on off ball valve. As the valve starts to open up (0%–40% open) the flow goes through the upstream tapered entrance or v-slot (first stage of drop) and then passes through the slots in the parallel slotted plates (four stages of drop) then passes through the outlet tapered exit or v-slot (sixth stage of drop). As the valve goes through between 40%–50% open the flow starts to bypass the outer plates and the valve will exhibit a four stage drop (2 through the seats, 2 through the inner plates). As the valve goes between 50% open to 100% open, the flow will bypass the outer plates and give the maximum flow velocity. 
   The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Technology Category: f