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CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 11/951,802, filed 6 Dec. 2007 (issuing as U.S. Pat. No. 7,841,410 on 30 Nov. 2010), which is a continuation in part of U.S. patent application Ser. No. 11/749,591, filed 16 May 2007 (issued as U.S. Pat. No. 7,607,481 on 27 Oct. 2009), each of which is hereby incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and apparatus that is of particular utility in cementing operations associated with oil and gas well exploration and production. More specifically the present invention provides an improvement to cementing operations and related operations employing a plug or ball dropping head. 
     2. General Background of the Invention 
     Patents have issued that relate generally to the concept of using a plug, dart or a ball that is dispensed or dropped into the well or “down hole” during oil and gas well drilling and production operations, especially when conducting cementing operations. The following possibly relevant patents are incorporated herein by reference. The patents are listed numerically. The order of such listing does not have any significance. 
     
       
         
               
               
               
             
           
               
                 TABLE 
               
               
                   
               
               
                 Pat. No. 
                 TITLE 
                 ISSUE DATE 
               
               
                   
               
             
             
               
                 3,828,852 
                 Apparatus for Cementing Well Bore Casing 
                 Aug. 13, 1974 
               
               
                 4,427,065 
                 Cementing Plug Container and Method of 
                 Jan. 24, 1984 
               
               
                   
                 Use Thereof 
               
               
                 4,624,312 
                 Remote Cementing Plug Launching System 
                 Nov. 25, 1986 
               
               
                 4,671,353 
                 Apparatus for Releasing a Cementing Plug 
                 Jun. 09, 1987 
               
               
                 4,722,389 
                 Well Bore Servicing Arrangement 
                 Feb. 02, 1988 
               
               
                 4,782,894 
                 Cementing Plug Container with Remote 
                 Nov. 08, 1988 
               
               
                   
                 Control System 
               
               
                 4,854,383 
                 Manifold Arrangement for use with a Top 
                 Aug. 08, 1989 
               
               
                   
                 Drive Power Unit 
               
               
                 4,995,457 
                 Lift-Through Head and Swivel 
                 Feb. 26, 1991 
               
               
                 5,095,988 
                 Plug Injection Method and Apparatus 
                 Mar. 17, 1992 
               
               
                 5,236,035 
                 Swivel Cementing Head with Manifold 
                 Aug. 17, 1993 
               
               
                   
                 Assembly 
               
               
                 5,293,933 
                 Swivel Cementing Head with Manifold 
                 Mar. 15, 1994 
               
               
                   
                 Assembly Having Remove Control Valves 
               
               
                   
                 and Plug Release Plungers 
               
               
                 5,435,390 
                 Remote Control for a Plug-Dropping Head 
                 Jul. 25, 1995 
               
               
                 5,758,726 
                 Ball Drop Head With Rotating Rings 
                 Jun. 02, 1998 
               
               
                 5,833,002 
                 Remote Control Plug-Dropping Head 
                 Nov. 10, 1998 
               
               
                 5,856,790 
                 Remote Control for a Plug-Dropping Head 
                 Jan. 05, 1999 
               
               
                 5,960,881 
                 Downhole Surge Pressure Reduction System 
                 Oct. 05, 1999 
               
               
                   
                 and Method of Use 
               
               
                 6,142,226 
                 Hydraulic Setting Tool 
                 Nov. 07, 2000 
               
               
                 6,182,752 
                 Multi-Port Cementing Head 
                 Feb. 06, 2001 
               
               
                 6,390,200 
                 Drop Ball Sub and System of Use 
                 May 21, 2002 
               
               
                 6,575,238 
                 Ball and Plug Dropping Head 
                 Jun. 10, 2003 
               
               
                 6,672,384 
                 Plug-Dropping Container for Releasing a 
                 Jan. 06, 2004 
               
               
                   
                 Plug Into a Wellbore 
               
               
                 6,904,970 
                 Cementing Manifold Assembly 
                 Jun. 14, 2005 
               
               
                 7,066,249 
                 Cementing Manifold Assembly 
                 Jul. 27, 2006 
               
               
                   
               
             
          
         
       
     
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an improved method and apparatus for use in cementing and like operations, employing a plug or ball dropping head of improved configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: 
         FIGS. 1A ,  1 B,  1 C are partial sectional elevation views of the preferred embodiment of the apparatus of the present invention wherein line A-A of  FIG. 1A  matches line A-A of  FIG. 1B , and line B-B of  FIG. 1B  matches line B-B of  FIG. 1C ; 
         FIG. 2  is a partial, sectional, elevation view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 3  is a partial, sectional, elevation view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 4  is a sectional view taken long lines  4 - 4  of  FIG. 2 ; 
         FIG. 5  is a sectional view taken along lines  5 - 5  of  FIG. 3 ; 
         FIG. 6  is a partial perspective view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 7  is a sectional elevation view of the preferred embodiment of the apparatus of the present invention and illustrating a method step of the present invention; 
         FIG. 8  is a sectional elevation view of the preferred embodiment of the apparatus of the present invention and illustrating a method step of the present invention; 
         FIG. 9  is an elevation view of the preferred embodiment of the apparatus of the present invention and illustrating the method of the present invention; 
         FIG. 10  is a sectional elevation view illustrating part of the method of the present invention and wherein line A-A of  FIG. 10  matches line A-A of  FIG. 9 ; 
         FIG. 11  is a sectional elevation view illustrating part of the method of the present invention and wherein line A-A of  FIG. 11  matches line A-A of  FIG. 9 ; 
         FIG. 12  is a sectional elevation view illustrating part of the method of the present invention; 
         FIG. 13  is a sectional elevation view illustrating part of the method of the present invention; 
         FIG. 14  is a sectional elevation view illustrating part of the method of the present invention and wherein line A-A of  FIG. 14  matches line A-A of  FIG. 9 ; 
         FIG. 15  is a sectional elevation view illustrating part of the method of the present invention and wherein line A-A of  FIG. 15  matches line A-A of  FIG. 9 ; 
         FIG. 16  is a sectional elevation view illustrating part of the method of the present invention; 
         FIG. 17  is a partial perspective view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 18  is a partial view of the preferred embodiment of the apparatus of the present invention and showing a ball valving member; 
         FIG. 19  is a partial side view of the preferred embodiment of the apparatus of the present invention and showing an alternate construction for the ball valving member; 
         FIG. 20  is a partial view of the preferred embodiment of the apparatus of the present invention and showing a ball valving member; 
         FIG. 21  is a partial side view of the preferred embodiment of the apparatus of the present invention and showing an alternate construction for the ball valving member; 
         FIG. 22  is a sectional view of the preferred embodiment of the apparatus of the present invention showing an alternate sleeve arrangement; 
         FIG. 23  is a sectional view of the preferred embodiment of the apparatus of the present invention showing an alternate sleeve arrangement; 
         FIG. 24  is a fragmentary view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 25  is a fragmentary view of the preferred embodiment of the apparatus of the present invention; and 
         FIG. 26  is a fragmentary view of the preferred embodiment of the apparatus of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 9  shows generally an oil well drilling structure  10  that can provide a platform  11  such as a marine platform as shown. Such platforms are well known. Platform  11  supports a derrick  12  that can be equipped with a lifting device  21  that supports a top drive unit  13 . Such a derrick  12  and top drive unit  13  are well known. A top drive unit can be seen for example in U.S. Pat. Nos. 4,854,383 and 4,722,389 which are incorporated herein by reference. 
     A flow line  14  can be used for providing a selected fluid such as a fluidized cement or fluidized setable material to be pumped into the well during operations which are known in the industry and are sometimes referred to as cementing operations. Such cementing operations are discussed for example in prior U.S. Pat. Nos. 3,828,852; 4,427,065; 4,671,353; 4,782,894; 4,995,457; 5,236,035; 5,293,933; and 6,182,752, each of which is incorporated herein by reference. 
     A tubular member  22  can be used to support plug dropping head  15  at a position below top drive unit  13  as shown in  FIG. 9 . String  16  is attached to the lower end portion of plug dropping head  15 . 
     In  FIG. 9 , the platform  11  can be any oil and gas well drilling platform such as a marine platform shown in a body of water  18  that provides a seabed or mud line  17  and water surface  19 . Such a platform  11  provides a platform deck  20  that affords space for well personnel to operate and for the storage of necessary equipment and supplies that are needed for the well drilling operation. 
     A well bore  23  extends below mud line  17 . In  FIGS. 10 and 11 , the well bore  23  can be surrounded with a surface casing  24 . The surface casing  24  can be surrounded with cement/concrete  25  that is positioned in between a surrounding formation  26  and the surface casing  24 . Similarly, a liner or production casing  32  extends below surface casing  24 . The production casing  32  has a lower end portion that can be fitted with a casing shoe  27  and float valve  28  as shown in  FIGS. 10-16 . Casing shoe  27  has passageway  30 . Float valve  28  has passageway  29 . 
     The present invention provides an improved method and apparatus for dropping balls, plugs, darts or the like as a part of a cementing operation. Such cementing operations are in general known and are employed for example when installing a liner such as liner  32 . In the drawings, arrows  75  indicate generally the flow path of fluid (e.g. cement, fluidized material or the like) through the tool body  34 . In that regard, the present invention provides an improved ball or plug or dart dropping head  15  that is shown in  FIGS. 1-8  and  10 - 17 . In  FIGS. 1A ,  1 B,  1 C and  2 - 8 , ball/plug dropping head  15  has an upper end portion  31  and a lower end portion  33 . Ball/plug dropping head  15  provides a tool body  34  that can be of multiple sections that are connected together, such as with threaded connections. In  FIGS. 1A-1C , the tool body  34  includes sections  35 ,  36 ,  37 ,  38 ,  39 . The section  35  is an upper section. The section  39  is a lower section. 
     Ball/plug dropping head  15  can be pre-loaded with a number of different items to be dropped as part of a cementing operation. For example, in  FIGS. 1A ,  1 B,  1 C there are a number of items that are contained in ball/plug dropping head  15 . These include an upper, larger diameter ball dart  40 ,  41  and smaller diameter ball  42 . In  FIGS. 18-26 , an alternate embodiment is shown which enables very small diameter balls, sometimes referred to as “frac-balls”  102  (which can have a diameter of between about ½ and ⅝ inches) to be dispensed into the well below toll body  34 . 
     The tool body  34  supports a plurality of valving members at opposed openings  90 . The valving members can include first valving member  43  which is an upper valving member. The valving members can include a second valving member  44  which is in between the first valving member  43  and a lower or third valving member  45 . Valving member  43  attaches to tool body  34  at upper opening positions  61 ,  62 . Valving member  44  attaches to tool body  34  at middle opening positions  63 ,  64 . Valving member  45  attaches to tool body  43  at lower opening positions  65 ,  66 . 
     Threaded connections  46 ,  47 ,  48 ,  49  can be used for connecting the various body sections  35 ,  36 ,  37 ,  38 ,  39  together end to end as shown in  FIGS. 1A ,  1 B,  1 C. Tool body  34  upper end  31  is provided with an internally threaded portion  50  for forming a connection with tubular member  22  that depends from top drive unit  13  as shown in  FIG. 9 . A flow bore  51  extends between upper end  31  and lower end  33  of tool body  34 . 
     Sleeve sections  52  are secured to tool body  34  within bore  15  as shown in  FIGS. 1A ,  1 B,  1 C. Sleeves  52  can be generally centered within bore  51  as shown in  FIGS. 1A ,  1 B,  1 C using spacers  67  that extend along radial lines from the sections  35 - 39 . 
     Each valving member  43 ,  44 ,  45  is movable between open and closed positions. In  FIGS. 1A ,  1 B,  1 C each of the valving members  43 ,  44 ,  45  is in a closed position. In that closed position, each valving member  43 ,  44 ,  45  prevents downward movement of a plug, ball  40 ,  42 , or dart  41  as shown. In  FIG. 1A , the closed position of valving member  43  prevents downward movement of larger diameter ball  40 . Similarly, in  FIG. 1B , a closed position of valving member  44  prevents a downward movement of dart  41 . In  FIG. 1B , a closed position of valving member  45  prevents a downward movement of smaller diameter ball  42 . In each instance, the ball, dart or plug rests upon the outer curved surface  68  of valving member  43 ,  44  or  45  as shown in the drawings. 
     Each valving member  43 ,  44 ,  45  provides a pair of opposed generally flat surfaces  69 ,  70  (see  FIGS. 3 ,  6 ,  17 ).  FIG. 17  shows in more detail the connection that is formed between each of the valving members  43 ,  44 ,  45  and the tool body  34 . The tool body  34  provides opposed openings  90  that are receptive the generally cylindrically shaped valve stems  54 ,  55  that are provided on the flat sections or flat surfaces  69 ,  70  of each valving member  43 ,  44 ,  45 . For example, in  FIGS. 6 and 17 , the flat surface  69  provides valve stem  54 . Openings  90  are receptive of the parts shown in exploded view in  FIG. 17  that enable a connection to be formed between the valving member  43 ,  44  or  45  and the tool body  34 . For the stem  55 , fastener  91  engages an internally threaded opening of stem  55 . Bushing  92  is positioned within opening  90  and the outer surface of stem  55  registers within the central bore  95  of bushing  92 . Bushing  92  is externally threaded at  93  for engaging a correspondingly internally threaded portion of tool body  34  at opening  90 . O-rings  60  can be used to interface between stem  55  and bushing  92 . A slightly different configuration is provided for attaching stem  54  to tool body  34 . Sleeve  94  occupies a position that surrounds stem  54 . Sleeve  54  fits inside of bore  95  of bushing  92 . The externally threaded portion  93  of bushing  92  engages correspondingly shaped threads of opening  90 . Pins  99  form a connection between the stem  54  at openings  98  and the sleeve  94 . Fastener  96  forms a connection between bushing  92  and an internally threaded opening  97  of stem  54 . As assembled, this configuration can be seen in  FIG. 1A  for example. The flat surfaces  69 ,  70  enable fluid to flow in bore  51  in a position radially outwardly or externally of sleeve or sleeve section  52  by passing between the tool body sections  35 ,  36 ,  37 ,  38 ,  39  and sleeve  52 . Thus, bore  51  is divided into two flow channels. These two flow channels  71 ,  72  include a central flow channel  71  within sleeves  52  that is generally cylindrically shaped and that aligns generally with the channel  53  of each valving member  43 ,  44 ,  45 . The second flow channel is an annular outer flow channel  72  that is positioned in between a sleeve  52  and the tool body sections  35 ,  36 ,  37 ,  38 ,  39 . The channels  71 ,  72  can be concentric. The outer channel  72  is open when the valving members  43 ,  44 ,  45  are in the closed positions of  FIGS. 1A ,  1 B and  1 C, wherein central flow channel  71  is closed. 
     When the valving members  43 ,  44 ,  45  are rotated to a closed position, fins  73  become transversely positioned with respect to the flow path of fluid flowing in channel  72  thus closing outer flow channel  72  (see  FIG. 5 ). This occurs when a valving member  43 ,  44 ,  45  is opened for releasing a ball  40  or  42  or for releasing dart  41 .  FIG. 4  illustrates a closed position ( FIG. 4 ) of the valving member  45  just before releasing smaller diameter ball  42 . Fins  73  are generally aligned with bore  15  and with flow channels  71 ,  72  when flow in channel  72  is desired ( FIG. 4 ). In  FIG. 4 , valving member  45  is closed and outer flow channel  72  is open. 
     In  FIGS. 2-3 ,  5  and  7 - 8 , a tool  74  has been used to rotate valving member  45  to an open position that aligns its channel  53  with central flow channel  71  enabling smaller diameter ball  42  to fall downwardly via central flow channel  71  ( FIG. 8 ). In  FIG. 5 , outer flow channel  72  has been closed by fins  73  that have now rotated about 90 degrees from the open position of  FIG. 4  to the closed position. Fins  73  close channel  72  in  FIG. 5 . It should be understood that tool  74  can also be used to rotate valving member  44  from an open position of  FIG. 1B  to a closed position such as is shown in  FIG. 5  when it is desired that dart  41  should drop. Similarly, tool  74  can be used to rotate upper valving member  43  from the closed position of  FIG. 1A  to an open position such as is shown in  FIG. 5  when it is desired to drop larger diameter ball  40 . 
       FIGS. 7-16  illustrate further the method and apparatus of the present invention. In  FIG. 8 , lower or third valving member  45  has been opened as shown in  FIG. 5  releasing smaller diameter ball  42 . In  FIG. 8 , smaller diameter ball  42  is shown dropping wherein it is in phantom lines, its path indicated schematically by arrows  75 . 
       FIG. 10  shows a pair of commercially available, known plugs  76 ,  77 . These plugs  76 ,  77  include upper plug  76  and lower plug  77 . Each of the plugs  76 ,  77  can be provided with a flow passage  79 ,  81  respectively that enables fluid to circulate through it before ball  42  forms a seal upon the flow passage  81 . Smaller diameter ball  42  has seated upon the lower plug  77  in  FIG. 10  so that it can now be pumped downwardly, pushing cement  80  ahead of it. In  FIG. 11 , arrows  78  schematically illustrate the downward movement of lower plug  77  when urged downwardly by a pumped substance such as a pumpable cement or like material  80 . Each of the plugs  76 ,  77  can be provided with a flow passage  79 ,  81  respectively that enables fluid to circulate through it before ball  42  forms a seal upon the flow passage  81  (see  FIG. 11 ). When plug  77  reaches float valve  28 , pressure can be increased to push ball  42  through plug  77 , float valve  28  and casing shoe  27  so that the cement flows (see arrows  100 ,  FIG. 11 ) into the space  101  between formation  26  and casing  32 . 
     In  FIG. 12 , second valving member  44  is opened releasing dart  41 . Dart  41  can be used to push the cement  80  downwardly in the direction of arrows  82 . A completion fluid or other fluid  83  can be used to pump dart  41  downwardly, pushing cement  80  ahead of it. Once valves  44  and  45  are opened, fluid  83  can flow through openings  84  provided in sleeves  52  below the opened valving member (see  FIG. 7 ) as illustrated in  FIGS. 7 and 12 . Thus, as each valving member  43  or  44  or  45  is opened, fluid moves through the openings  84  into central flow channel  71 . 
     When valve  44  is opened, dart  41  can be pumped downwardly to engage upper plug  76 , registering upon it and closing its flow passage  79 , pushing it downwardly as illustrated in  FIGS. 14 and 15 . Upper plug  79  and dart  41  are pumped downwardly using fluid  83  as illustrated in  FIGS. 14 and 15 . In  FIG. 16 , first valving member  43  is opened so that larger diameter ball  40  can move downwardly, pushing any remaining cement  80  downwardly. 
     The ball  40  can be deformable, so that it can enter the smaller diameter section  86  at the lower end portion of tool body  34 . During this process, cement or like mixture  80  is forced downwardly through float collar  28  and casing shoe  27  into the space that is in between production casing and formation  26 . This operation helps stabilize production casing  32  and prevents erosion of the surrounding formation  26  during drilling operations. 
     During drilling operations, a drill bit is lowered on a drill string using derrick  12 , wherein the drill bit simply drills through the production casing  32  as it expands the well downwardly in search of oil. 
       FIGS. 18-26  show an alternate embodiment of the apparatus of the present invention, designated generally by the numeral  110  in  FIGS. 22-23 . In  FIGS. 18-26 , the flow openings  84  in sleeves  52  of ball/plug dropping head  110  of  FIGS. 1-17  have been eliminated. Instead, sliding sleeves  111  are provided that move up or down responsive to movement of a selected valving member  112 ,  113 . It should be understood that the same tool body  34  can be used with the embodiment of  FIGS. 18-26 , connected in the same manner shown in  FIGS. 1-17  to tubular member  22  and string  16 . In  FIGS. 18-26 , valving members  112 ,  113  replace the valving members  43 ,  44 ,  45  of  FIGS. 1-17 . In  FIGS. 18-26 , sleeves  111  replace sleeves  52 . While two valving members  112 ,  113  are shown in  FIGS. 22 ,  23 , it should be understood that three such valving members (and a corresponding sleeve  111 ) could be employed, each valving member  112 ,  113  replacing a valving member  43 ,  44 ,  45  of  FIGS. 1-17 . 
     In  FIGS. 18-26 , tool body  34  has upper and lower end portions  31 ,  33 . As with the preferred embodiment of  FIGS. 1-17 , a flow bore  51  provides a central flow channel  71  and outer flow channel  72 . Each valving member  112 ,  113  provides a valve opening  114 . Each valving member  112 ,  113  provides a flat surface  115  (see  FIG. 20 ). Each valving member  112 ,  113  provides a pair of opposed curved surfaces  116  as shown in  FIG. 20  and a pair of opposed flat surfaces  117 , each having a stem  119  or  120 . 
     An internal, generally cylindrically shaped surface  118  surrounds valve opening  114  as shown in  FIG. 20 . Each valving member  112 ,  113  provides opposed stems  119 ,  120 . Each valving member  112 ,  113  rotates between opened and closed positions by rotating upon stems  119 ,  120 . Each of the stems  119 ,  120  is mounted in a stem opening  90  of tool body  34  at positions  61 ,  62  and  63 ,  64  as shown in  FIG. 22 . 
     In  FIG. 19 , valving member  122 ,  123  is similar in configuration and in sizing to the valving members  43 ,  44 ,  45  of the preferred embodiment of  FIGS. 1-17 , with the exception of a portion that has been removed which is indicated in phantom lines in  FIG. 19 . The milled or cut-away portion of the valving member  112 ,  113  is indicated schematically by the arrow  121 . Reference line  122  in  FIG. 19  indicates the final shape of valving member  112 ,  113  after having been milled or cut. In  FIGS. 20 and 21 , a beveled edge at  123  is provided for each valving member  112 ,  113 . 
     When a valving member  112 ,  113  is in the closed position of  FIG. 22 , flow arrows  124  indicate the flow of fluid through the tool body  34  bore  51  and more particularly in the outer channel  72  as indicated in  FIG. 22 . 
     In  FIG. 23 , the lower valving member  113  has been rotated to an open position as indicated schematically by the arrow  134 , having been rotated with tool  74 . In this position, fins  73  now block the flow of fluid in outer channel  72 . Flat surface  115  now faces upwardly. In this position, the cut-away portion of valving member  113  that is indicated schematically by the arrow  121  in  FIG. 19  now faces up. Sliding sleeve  111  drops downwardly as indicated schematically by arrows  130  when a valving member  112  or  113  is rotated to an open position (see valving member  113  in  FIG. 23 ). In  FIG. 22 , a gap  129  was present in between upper valve  112  and sleeve  111  that is below the valve  112 . The sleeve  111  that is in between the valves  112 , 113  is shown in  FIG. 22  as being filled with very small diameter balls or “frac-balls”  102 . 
     When valving member  113  is rotated to the open position of  FIG. 23 , the gap is now a larger gap, indicated as  135 . Gap  135  (when compared to smaller gap  129 ) has become enlarged an amount equal to the distance  121  illustrated by arrow  121  in  FIG. 19 . The frac-balls  102  now drop through valving member  113  as illustrated by arrows  127  in  FIG. 23 . Arrows  125 ,  126  in  FIG. 23  illustrate the flow of fluid downwardly through gap  135  and in central channel  71 . 
     A sleeve  111  above a valving member  112  or  113  thus move up and down responsive to a rotation of that valving member  112  or  113 . Spacers  28  can be employed that extend from each sleeve  111  radially to slidably engage tool body  34 . In  FIGS. 20 and 21 , each stem  119 ,  120  can be provided with one or more annular grooves  131  that are receptive of o-rings  60  or other sealing material. As with the preferred embodiment of  FIGS. 1-17 , openings  132  in each stem  119 ,  120  are receptive of pins  99 . Likewise, each stem  119 ,  120  provides internally threaded openings  133 . Thus, the same connection for attaching a valving member  112 ,  113  to tool body  34  can be the one shown in  FIGS. 1-17 . 
     The following is a list of parts and materials suitable for use in the present invention. 
     
       
         
               
             
               
               
             
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
             
          
           
               
                 Part Number 
                 Description 
               
               
                   
               
             
          
           
               
                 10 
                 oil well drilling structure 
               
               
                 11 
                 platform 
               
               
                 12 
                 derrick 
               
               
                 13 
                 top drive unit 
               
               
                 14 
                 flow line 
               
               
                 15 
                 ball/plug dropping head 
               
               
                 16 
                 string 
               
               
                 17 
                 sea bed/mud line 
               
               
                 18 
                 body of water 
               
               
                 19 
                 water surface 
               
               
                 20 
                 platform deck 
               
               
                 21 
                 lifting device 
               
               
                 22 
                 tubular member 
               
               
                 23 
                 well bore 
               
               
                 24 
                 surface casing 
               
               
                 25 
                 cement/concrete 
               
               
                 26 
                 formation 
               
               
                 27 
                 casing shoe 
               
               
                 28 
                 float valve 
               
               
                 29 
                 passageway 
               
               
                 30 
                 passageway 
               
               
                 31 
                 upper end 
               
               
                 32 
                 liner/production casing 
               
               
                 33 
                 lower end portion 
               
               
                 34 
                 tool body 
               
               
                 35 
                 section 
               
               
                 36 
                 section 
               
               
                 37 
                 section 
               
               
                 38 
                 section 
               
               
                 39 
                 section 
               
               
                 40 
                 larger diameter ball 
               
               
                 41 
                 dart 
               
               
                 42 
                 smaller diameter ball 
               
               
                 43 
                 first valving member 
               
               
                 44 
                 second valving member 
               
               
                 45 
                 third valving member 
               
               
                 46 
                 threaded connection 
               
               
                 47 
                 threaded connection 
               
               
                 48 
                 threaded connection 
               
               
                 49 
                 threaded connection 
               
               
                 50 
                 threaded portion 
               
               
                 51 
                 flow bore 
               
               
                 52 
                 sleeve 
               
               
                 53 
                 channel 
               
               
                 54 
                 stem 
               
               
                 55 
                 stem 
               
               
                 56 
                 sleeve 
               
               
                 57 
                 sleeve 
               
               
                 58 
                 plug 
               
               
                 59 
                 plug 
               
               
                 60 
                 o-ring 
               
               
                 61 
                 opening position 
               
               
                 62 
                 opening position 
               
               
                 63 
                 opening position 
               
               
                 64 
                 opening position 
               
               
                 65 
                 opening position 
               
               
                 66 
                 opening position 
               
               
                 67 
                 spacer 
               
               
                 68 
                 outer curved surface 
               
               
                 69 
                 flat surface 
               
               
                 70 
                 flat surface 
               
               
                 71 
                 central flow channel 
               
               
                 72 
                 outer flow channel 
               
               
                 73 
                 fin 
               
               
                 74 
                 tool 
               
               
                 75 
                 arrow 
               
               
                 76 
                 upper plug 
               
               
                 77 
                 lower plug 
               
               
                 78 
                 arrows 
               
               
                 79 
                 flow passage 
               
               
                 80 
                 cement 
               
               
                 81 
                 flow passage 
               
               
                 82 
                 arrow 
               
               
                 83 
                 fluid 
               
               
                 84 
                 opening 
               
               
                 85 
                 opening 
               
               
                 86 
                 smaller diameter section 
               
               
                 87 
                 arrow - fluid flow path 
               
               
                 88 
                 fastener 
               
               
                 89 
                 internally threaded opening 
               
               
                 90 
                 opening 
               
               
                 91 
                 fastener 
               
               
                 92 
                 bushing 
               
               
                 93 
                 external threads 
               
               
                 94 
                 sleeve 
               
               
                 95 
                 passageway/bore 
               
               
                 96 
                 fastener 
               
               
                 97 
                 internally threaded opening 
               
               
                 98 
                 opening 
               
               
                 99 
                 pin 
               
               
                 100 
                 arrows 
               
               
                 101 
                 space 
               
               
                 102 
                 frac-ball 
               
               
                 110 
                 ball/plug dropping head 
               
               
                 111 
                 sleeve 
               
               
                 112 
                 valving member 
               
               
                 113 
                 valving member 
               
               
                 114 
                 valve opening 
               
               
                 115 
                 flat surface 
               
               
                 116 
                 curved surface 
               
               
                 117 
                 flat surface 
               
               
                 118 
                 internal surface 
               
               
                 119 
                 stem 
               
               
                 120 
                 stem 
               
               
                 121 
                 arrow 
               
               
                 122 
                 reference line 
               
               
                 123 
                 beveled edge 
               
               
                 124 
                 arrow 
               
               
                 125 
                 arrow 
               
               
                 126 
                 arrow 
               
               
                 127 
                 arrow 
               
               
                 128 
                 spacer 
               
               
                 129 
                 smaller gap 
               
               
                 130 
                 arrow sleeve movement 
               
               
                 131 
                 annular groove 
               
               
                 132 
                 opening 
               
               
                 133 
                 internally threaded opening 
               
               
                 134 
                 arrow 
               
               
                 135 
                 larger gap 
               
               
                   
               
             
          
         
       
     
     All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise. 
     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.

Summary:
An improved method and apparatus for dropping a ball, plug or dart during oil and gas well operations (e.g., cementing operations) employs a specially configured valving member with curved and flat portions that alternatively direct fluid flow through a bore or opening in the valving member via an inner channel or around the periphery of the valving member in an outer channel. In one embodiment, the ball(s), dart(s) or plug(s) are contained in a sliding sleeve that shifts position responsive to valve rotation.