Ball-seat apparatus and method

Abstract

An apparatus for restricting fluid flow includes: a ball receiving element disposed in a fluid conduit and configured to receive a ball that has been advanced through the fluid conduit and at least partially restrict fluid flow, the fluid conduit having a longitudinal axis; and at least one feature disposed at the fluid conduit and configured to at least one of reduce a rate of deceleration of the ball due to actuation of the apparatus and reduce pressure waves generated by an impact between the ball and the ball receiving element.

1 . An apparatus for restricting fluid flow, comprising:
 a ball receiving element disposed in a fluid conduit and configured to receive a ball that has been advanced through the fluid conduit and at least partially restrict fluid flow, the fluid conduit having a longitudinal axis; and   at least one feature disposed at the fluid conduit and configured to at least one of reduce a rate of deceleration of the ball due to actuation of the apparatus and reduce pressure waves generated by an impact between the ball and the ball receiving element.   
     
     
         2 . The apparatus of  claim 1 , wherein the at least one feature is included in the ball receiving element, and the at least one feature includes:
 at least one first seating component disposed at the conduit and protruding radially into the conduit, the at least one first seating component configured to contact the ball and reduce a velocity of the ball; and   a second seating component protruding radially into the conduit and disposed at a downstream location relative to the first seating assembly, the second seating assembly configured to prevent downstream movement of the ball.   
     
     
         3 . The apparatus of  claim 2 , wherein the at least one first seating component has a cross-sectional shape configured to form one or more first fluid passageways therethrough upon contact with the ball. 
     
     
         4 . The apparatus of  claim 3 , wherein the at least one first seating component includes a plurality of axially successive circumferentially offset seating components. 
     
     
         5 . The apparatus of  claim 4 , wherein respective fluid passageways in each of the plurality of seating components are offset from one another so that a total cross-sectional area of the fluid passageways successively decreases as the ball advances through the ball receiving element. 
     
     
         6 . The apparatus of  claim 3 , wherein the second seating component has a cross-sectional shape configured to form one or more second fluid passageways therethrough upon contact with the ball, and the second fluid passageways are circumferentially offset relative to the one or more first fluid passageways. 
     
     
         7 . The apparatus of  claim 6 , wherein the ball forms a complete fluid seal with the first and second seating components when seated. 
     
     
         8 . The apparatus of  claim 3 , wherein the at least one first seating component includes a plurality of first axially tapered members, each first axially tapered member arranged circumferentially and forming a first fluid passage with an adjacent first tapered member. 
     
     
         9 . The apparatus of  claim 8 , wherein the second seating component includes a plurality of second axially tapered members circumferentially offset relative to the plurality of first members, each second axially tapered member arranged circumferentially and forming a second fluid passage with an adjacent second tapered member. 
     
     
         10 . The apparatus of  claim 2 , wherein each of the first and second seating components have an axial contour that increases gradually in the downstream direction. 
     
     
         11 . The apparatus of  claim 2 , wherein each of the at least one first seating component and the second seating component include at least one of a selected resistance to movement and axial contour configured to reduce a velocity of the ball by a selected amount upon contact with the ball. 
     
     
         12 . The apparatus of  claim 11 , wherein at least one of the resistance to movement and the axial contour of the second seating component is sufficient to stop the ball after contact with the first seating component. 
     
     
         13 . A method of restricting fluid flow, comprising:
 releasing a ball into a fluid conduit and receiving the ball in a ball receiving element disposed at the fluid conduit and at least partially restricting fluid flow, the fluid conduit having a longitudinal axis; and   at least one of reducing a rate of deceleration of the ball due to actuation of the apparatus and reducing pressure waves generated by an impact between the ball and the ball receiving element by at least one feature disposed at the fluid conduit.   
     
     
         14 . The method of  claim 13 , wherein the at least one feature is included in the ball receiving element, and the at least one feature includes:
 at least one first seating component disposed at the conduit and protruding radially into the conduit, the at least one first seating component configured to contact the ball and reduce a velocity of the ball; and   a second seating component protruding radially into the conduit and disposed at a downstream location relative to the first seating component, the second seating component configured to prevent downstream movement of the ball.   
     
     
         15 . The method of  claim 14 , further comprising reducing a velocity of the ball in successive increments by successively contacting the first seating component and the second seating component by the ball as the ball engages the ball receiving element. 
     
     
         16 . The method of  claim 14 , wherein the at least one first seating component has a cross-sectional shape configured to form one or more first fluid passageways therethrough upon contact with the ball. 
     
     
         17 . The method of  claim 16 , further comprising reducing a fluid flow through the ball seat in successive increments by successively contacting the first seating component and the second seating component by the ball as the ball engages the ball receiving element. 
     
     
         18 . The method of  claim 17 , wherein the ball forms a complete fluid seal with the first and second seating components when seated. 
     
     
         19 . The method of  claim 16 , wherein the at least one first seating component includes a plurality of axially successive circumferentially offset seating components, and respective fluid passageways in each of the plurality of seating components are offset from one another so that a total cross-sectional area of the respective fluid passageways successively decreases as the ball advances through the ball receiving element. 
     
     
         20 . The method of  claim 16 , wherein the second seating component has a cross-sectional shape configured to form one or more second fluid passageways therethrough upon contact with the ball, and the one or more second fluid passageways are circumferentially offset relative to the one or more first fluid passageways.