Patent Publication Number: US-2021190232-A1

Title: Ball valve with integral gear

Description:
CROSS-REFERENCE TO PRIOR APPLICATION 
     Priority is claimed to British Patent Application No. GB 1919194.9, filed on Dec. 23, 2019, the entire disclosure of which is hereby incorporated by reference herein. 
     FIELD 
     The invention relates to a ball valve, and more particularly to a ball valve where a gear member is integrally formed on the valve member. 
     BACKGROUND 
     Ball valves are well known as a means of controlling flow in a pipeline, and as the skilled person will be aware of how they operate, this will not be described in detail. Ball valves can be driven to rotate in a number of ways; for example, a shaft connected to the valve body can be directly rotated (by means such as a handwheel or a motor). 
     However, rather than direct drive, it is common for some form of epicyclic gear train or planetary gear to be used in the drive train. This can increase the torque applied to the valve body, which can make it easier to move the valve body and/or reduce the amount of torque which must be applied to a handwheel to operate the valve (see, for example, US 2013/0026397, where a series of planetary gear phases are used to increase the torque applied to a valve body). Further, the ball valve will rotate more slowly than the input drive shaft, and this can reduce the risk of water hammer and other unwanted effects of closing the valve too quickly (as explained in JPS 6065979). 
     In US 2013/0026397, the last planetary gear phase is attached to a gear which drives a pinion connected to the valve body. In JPS 6065979, the planetary gear has an input shaft coupled to a handwheel and an output shaft connected to the valve body. 
     SUMMARY 
     In an embodiment, the present invention provides a ball valve, comprising: a valve body, wherein the valve body is configured to be driven to rotate through a drive train that includes a planetary gear set, and wherein a gear of the planetary gear set is integrally formed with the valve body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be described in even greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. Other features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following: 
         FIG. 1  is a perspective view of a valve body for a ball valve in accordance with a currently preferred aspect of the invention; 
         FIG. 2  is a perspective view showing the valve body of  FIG. 1  as installed and connected to a drive mechanism; 
         FIG. 3  is an enlarged view of the planetary gear system, showing the directions of rotation of various parts of the planetary gear system; and 
         FIG. 4  is a schematic view of a part of a refuel manifold using a plurality of the ball valves. 
     
    
    
     DETAILED DESCRIPTION 
     In an embodiment, the present invention provides a ball valve with a valve body, wherein the valve body is driven to rotate through a drive train which includes a planetary gear set, and wherein a gear of the planetary gear set is integrally formed with the valve body. 
     Integrally forming a gear of the planetary gear set with the valve body reduces the number of parts in the valve system, and also reduces backlash in the drive system. 
     Either the ring gear or the sun gear of the planetary gear set may be integrally formed with the valve body. Preferably, it is the ring gear of the planetary gear set which is integrally formed with the valve body. 
     In a preferred embodiment, the gear of the planetary gear set is formed is a recess on an outer surface of the valve body. 
     Providing the gear in a recess means that the gear does not project beyond the outer surface of the valve body. As a result, conventional polishing procedures can be applied to the valve body. 
     The invention also extends to a refuel manifold for a gas turbine engine, including a plurality of ball valves as described above. 
     As shown in  FIG. 1 , the valve body  10  is generally spherical, with a flow passage  20  formed therethrough and passing through the centre of the sphere. The valve body  10  is arranged to rotate about an axis which is perpendicular to the axis of the flow passage  20 . When the flow passage  20  is aligned with a passage in the valve housing, fluid can flow through the valve and the valve is open. When the valve body is rotated around its axis of rotation through 90 degrees, the flow passage  20  is perpendicular to the passage in the valve housing, fluid cannot flow through the valve and the valve is closed. This arrangement is routine for a ball valve. Other arrangements (such as where the flow passage is L-shaped or T-shaped when seen along the axis of rotation) are well known. 
     Means for supporting the valve body  10  during rotation are provided at either end of the axis of rotation. In particular, at one end of the axis, there is provided a small projection  30  which projects into the flow passage  20 , as can be seen in  FIG. 1 . This projection is hollow, and thus forms a first recess which can accommodate a trunnion on the valve housing. 
     At the other end of the axis, a second recess  40  is formed on the outer surface of the valve body  10 . This second recess  40  is wider than the projection, and has an inner wall  42  surrounding and facing the axis of rotation, and a base wall  44  which is generally perpendicular to the axis of rotation. Teeth  46  are integrally formed on the inner wall  42 , and project radially inwards, towards the axis of rotation. Thus, the inner wall  42  of the second recess  40  can function as a ring gear. 
     As the ring gear is formed in a recess  40 , it does not project beyond the spherical surface of the valve body  10 . Accordingly, it is possible to use conventional polishing techniques on the spherical surface of the valve body  10 . 
     An additional recess  48  is formed in the base wall  44 , concentric with the axis of rotation. This additional recess  48  can accommodate the end of a shaft. 
     The skilled person will appreciate that the valve can function in any orientation. The valve body  10  is constrained to rotate about the axis of rotation by the engagement of the trunnion in the first recess, and the engagement of the shaft in the additional recess  48 . 
       FIG. 2  shows the valve body  10  mounted in a housing  50  and connected to a drive system  60 . As mentioned above, the toothed inner wall  42  of the second recess  40  can function as a ring gear in a planetary gear system.  FIGS. 2 and 3  show such a planetary gear system, with a plurality of planet gears  62  meshing with the toothed inner wall  42  and being carried by a planet carrier  64 . The planet gears  62  also mesh with a central sun gear; the sun gear is mounted on a shaft  66  that is accommodated in the additional recess  48 . 
     As shown in  FIG. 2 , an input shaft  70  is used to drive the planetary gear system. A pinion  72  is fixedly mounted on this shaft  70 , and the pinion  72  is in turn driven by a worm gear  74 . The pinion rotates in a direction indicated by the arrow labelled “1”, this rotation causes rotation of the planets around their axes in a direction indicated by the arrow labelled “2”, which in turn causes the ring gear (and thus the valve body) to rotate in a direction indicated by the arrow labelled “3”. 
     Accordingly, rotation of the worm gear  74  causes rotation of the valve body  10 ; the direction of rotation of the valve body  10  depends on the direction of rotation of the worm gear  74 . 
     Providing the ring gear as an integral part of the valve body  10  reduces the total number of parts in the valve, and can thus reduce the size and mass of the overall package of the valve and its drive system. Further, it reduces the risk of the planetary gear system becoming detached from the valve body  10  (through mechanical failure of a part). 
     In addition, as there are fewer parts involved in the drive train (as compared to a prior art ball valve using a planetary gear system), there is less backlash in the drive train. Thus, the valve body  10  can be positioned more accurately. This precision in positioning the valve body  10  allows a smaller ball valve to be used, and thus a further reduction in the size and mass of the overall system. 
     The system of the invention is particularly suited to use in aerospace applications, where size and mass are of considerable importance. The system finds particular use in a refuel manifold for a gas turbine engine of an aircraft, where four flow control devices (valves) must be packaged into a single removable component. A schematic view of part of such a manifold is shown in  FIG. 4  (although the fourth valve is not shown, and the second and third valves are only shown in part). The small size of the valve allows four valves to be packaged in a single manifold. Further, as the valve body can be driven by the gearbox rather than through adaptors and drive shafts, the entire flow control assembly can be packaged in a much smaller space. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those of ordinary skill within the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below. Additionally, statements made herein characterizing the invention refer to an embodiment of the invention and not necessarily all embodiments. 
     The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.