Abstract:
A flow-actuated actuator includes a plurality of rings positionable within a structure, each ring having a full bore therethrough, and a plurality of elongated members in operable communication with the plurality of rings providing orientation of each ring to at least one adjacent ring. The plurality of rings and the plurality of elongated members are configured to generate an urging force in response to fluid flow thereby.

Description:
BACKGROUND 
     Downhole system operators are always receptive to new methods and devices to permit actuation of tools located downhole within a downhole system. Increasing flow rates of fluid pumped from surface can and has been harnessed as a method to permit actuation of a number of different types of devices in the downhole environment. In such methods downhole actuators typically use reduced diameter elements that resist fluid flow resulting in actuation forces that are proportional to the flow rate. While these work well for their intended purpose, the reduced diameter elements can limit other operations simply due to diametrical patency. Commonly then such actuators are therefore generally removed from the downhole system to allow full bore access. Devices and methods that permit actuation based on flow while not incurring the drawback noted would be well received in the art. 
     BRIEF DESCRIPTION 
     Disclosed herein is a flow-actuated actuator. The actuator includes, a plurality of rings positionable within a structure, each ring having a full bore therethrough, and a plurality of elongated members in operable communication with the plurality of rings providing orientation of each ring to at least one adjacent ring, the plurality of rings and the plurality of elongated members configured to generate an urging force in response to fluid flow thereby. 
     Further disclosed herein is a method of actuating a tool. The method includes, positioning a plurality of rings within a structure in operable communication with a tool to be actuated, flowing fluid through the structure past the plurality of rings, urging the plurality of rings with the flowing fluid, and actuating the tool with the urging. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  depicts a cross sectional view of a flow-actuated actuator positioned within a structure; and 
         FIG. 2  depicts a partial perspective view of a portion of the flow-actuated actuator of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Referring to  FIGS. 1 and 2 , an embodiment of a flow-actuated actuator  10  is illustrated generally at  10 . The actuator  10  is a full bore actuator that does not present its own restriction to flow. Rather the actuator  10  presents an unencumbered full bore. As such, the actuator  10  creates no obstruction to full bore downhole access through the actuator  10  such as during an intervention, for example, yet provides a mechanism and method for actuating a downhole tool in response to fluid flow. Although embodiments depicted herein are in reference to downhole applications, it should be noted that the flow-actuated actuators described herein are not limited to downhole applications, and as such can be used in any application needing a flow-actuated actuator 
     The actuator  10  includes, a plurality of rings  14 , with six being shown, fixedly positioned longitudinally apart by a plurality of elongated members  18 , shown herein as rods, with four rods being shown, all positioned within a structure  20 , illustrated here as a tubular portion of a drillstring  30 , receptive of fluid flow therethrough. The rings  14  have a full bore dimension  22  that is no smaller than a smallest inner dimension  26  of the structure  20  or drill string  30 , such as at locations longitudinally beyond the actuator  10 . The structure  20  and the actuator  10  are shown herein illustrated within a downhole well bore  34 . The full bore dimension  22  allows access through and beyond the actuator  10  at the full bore dimension  22 , thereby negating the need to remove the actuator  10  from the well bore  34  prior to such an operation. 
     The longitudinal separation of the rings  14  allows fluid to flow between adjacent rings  14  up to a full inner dimension  38  of the tubular  20  within which the actuator  10  is positioned. Fluid can even flow through an annular space  46  defined by the outer dimension  50  of the rings  14  and the inner dimension  38  of the tubular  20 . By allowing fluid to fill the longitudinal volume between adjacent rings  14  (minus the volume of the elongated members  18 ), a greater resistance to fluid flow, by the actuator  10 , can be generated in comparison to a tubular shaped actuator, for example. This greater resistance to fluid flow creates a larger urging force on the actuator  10  which in turn can impart a greater actuation force on a downhole tool  54 , such as the illustrated flow tube  54 A, biasing member  54 B and flapper  54 C, for example, in this embodiment. Additionally, the rings  14  and rods  18  configuration of the actuator  10  create less frictional engagement with a wellbore  34  in comparison to a tubular shaped actuator thereby lessening losses in actuation force due to friction. 
     Referring to  FIG. 2 , a magnified perspective view of a portion of the actuator  10  is illustrated. In this embodiment, longitudinal holes  58 , equally spaced perimetrically about the ring  14  and extend through the ring  14 , allow the rods  18  to pass therethrough. Setscrews  62  threadably engaged with the ring  14  are tightened to longitudinally fix the ring  14  to the rods  18  through frictional engagement at selected locations along the rods  18 , while other attachment methods such as, welding, brazing, adhesive bonding, press fitting and threadable engagement are contemplated. Some of these attachment methods contemplated, such as the use of the setscrews  62 , for example, can additionally act as a centralizer. The foregoing structure allows an operator to fixedly attach each of the rings  14  at a specific location along the rods  18 . For example, each of the rings  14  may be positioned a same dimension from each of the adjacent rings  14 , as shown in  FIG. 1 , or they may be set at differing dimensions from each of the adjacent rings  14 . The spacing can be established for each particular application depending upon desired characteristics of actuation force in relation to flow. 
     Additionally, the rings  14  may include geometric details that influence the relationship between fluid flow and the resulting urging forces acting thereon. For example, tapering a surface  66  on a downstream end  70  of the rings  14  as defined by a direction of fluid flow (the surface  66  being on an inner radial side, as shown, or an outer radial side), or altering an angle of a leading surface  74  relative to an axis of the actuator  10  (the angle being 90 degrees as shown), or altering an overall longitudinal length  78  of the rings  14 , or altering an annular dimension from the full bore dimension  22  to the outer dimension  50 , of the rings  14 , to mention a few. Such geometric details can cause turbulence in the flow. Turbulence can increase urging forces acting upon the rings  14  by increasing local currents, such as eddy currents, for example. The rings  14  may be geometrically identical or may be unique relative to one another. Differing the rings  14  from one another may improve the urging forces over a wider flow range since the variation in the rings  14  will present a greater variation in dimensions that can create turbulence in the flow. 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.