Abstract:
An internal bidirectional tubing plug for plugging a well to prevent well fluids from passing the plug in a well conduit until the internal components of the plug are pumped out of its body. The body of the plug connects to the well&#39;s tubing string. The body holds a petal assembly consisting of several petals and a tapered cork assembly located within an opening formed by the petals. Both assemblies are sandwiched between upper and lower pistons. Hydrostatic pressure on the bottom of the plug as it is lowered into the fluid filled well holds the petals within the body. The internal components of the plug are removed from the body by applying hydraulic pressure in the upper area of the plug. This causes the plug to fail at a recess provided in the cork, resulting in the two assemblies and the pistons being forced out of the body.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is a closure means for well conduits in the form of an internal bidirectional tubing plug. The plug prevents well fluids from passing the plug in either direction in a well conduit until the plug is activated and pumped apart, and the pieces that comprise the plug are either pumped down or up a tubing string or down or up a casing or tubing annulus of the well or fall to the bottom of the well. The plug is activated or deconstructed in situ through application of hydraulic pressure on the top side of the plug. 
     2. Description of the Related Art 
     The present invention relates to closure means for well conduits. More particularly, it relates to temporary plugs that are removable without mechanical intervention from the surface above the well. Plugs are used to run new or used tubing, known as a work string, into a well filled with well fluids, usually drilling mud or water. The tubing is run behind a drill bit and drill collar, behind a packer or open ended as fast and as safely as possible. As the tubing is run into the well, the displaced well fluid is directed to a pit or tank while preventing the well fluid from entering the tubing, through a bit, a packer, or through an open end. 
     It is also desirable to prevent displaced well fluids from being displaced out the surface open end of the tubing into the atmosphere. The displaced well fluids will take the path of least resistance to the atmosphere. If the displaced well fluids are allowed to enter the tubing, well fluids will “spray” out the surface open end of the tubing. This spray of well fluids will coat the rig, rig crew, stripping rubber, blow out preventers, wellhead, and the ground and will generally impair safe working conditions. The spray may also contaminate the ground or create a fire or chemical hazard since some well fluids contain hazardous chemicals and compounds. 
     In general practice the tubing is lowered very slowly into a well to allow the well fluids to drain from the tubing/annulus casing valve, and slow enough to prevent well fluids from spraying out the open end of the tubing. This method of running a tubing string very slowly is costly to well operators due to the additional rig time. It is desirable to run the tubing as fast as possible, in a safe manner, to reduce the well operators cost. 
     One problem is controlling the well fluids from being displaced from the tubing/casing annulus while the tubing is being lowered into the well. This is accomplished by using a “stripping rubber”, as known in the art. The stripping rubber effectively seals the tubing/casing annulus diverting all displaced well fluids up the tubing and out the casing valve at the same time. The casing valve is generally placed on a kill-choke/spool below the blow out preventers. The casing valve is generally opened to a flow line ending at a flow back tank, frac tank, and or an earth pit. The flow lines that are directed to a flow back tank generally have sufficient restriction in them to not be able handle all of the displaced well fluids through the casing valve which causes more of the displaced well fluids to be directed into the tubing and out the end of it at the surface. 
     A second problem is that if the well operator chooses to run a stripping rubber and a drill pipe float valve above the bit, i.e. essentially a check valve, all displaced well fluids will be diverted to the casing valve and to a tank or pit. But using a drill pipe float valve causes another problem. 
     A third problem is that when using a drill pipe float valve and stripping rubber circulation of the well fluid may only occur down the tubing and up the tubing/casing annulus. There are situations where this setup may limit the control of the well by not allowing well fluids to be circulated down the tubing/casing annulus and up the tubing. 
     A fourth problem is that when using a drill pipe float valve with a stripping rubber and drilling out any obstructions in a well such as DV tools (known as stage cementing tools), DV rubbers, primary cementing rubbers and any excess cement left in the well, a high circulation rate is necessary to carry all drilled and washed debris up the tubing/casing annulus through the casing valve, flow line, and to a wash tank. If the casing valve or flow line become plugged circulation up the tubing/casing will be lost. If circulation is lost the annulus debris in the annulus will fall down hole around the tubing “sticking” the tubing. To remove the tubing a “fishing” job is required that is very expensive and for this reason this set up is not used by prudent operators. 
     A fifth problem is created when using a wire line (also known as “slick line”) retrievable “blanking plug”. One way to prevent well fluids from entering the tubing is to run a wire line retrievable blanking plug in a tubing nipple at or above the bottom end of the tubing. A retrievable blanking plug seals off fluid flow in both directions of the tubing. With a blanking plug in place while running the tubing, in conjunction with a stripping rubber, all displaced fluids are diverted through a casing valve. While picking up a new or used work string and running it into the well, there will be mill scale, rust, dirt, tubing dope, and all manner of debris that will fall down the tubing and land on top of the blanking plug. 
     Once the tubing is at depth the tubing is filled with fluid to equalize differential pressure across the retrievable blanking plug so that it may be removed from the tubing. This is accomplished by running a wireline blanking plug retrieval tool, and in some cases, an equalizing prong, to release the retrievable blanking plugs latching members from a tubing sub known as a nipple. However, in most cases tubing debris, as mentioned above, have fallen down and covered the retrievable blanking plug such that the retrievable tool and equalizing prong cannot engage the blanking plug to equalize, release, and pull it from the tubing to the surface. At this time the debris must be washed off the retrievable blanking plug before it is pulled from the tubing. This may be accomplished by using coiled tubing and or snubbing operations or other methods, which incur additional cost and time. Sometimes the fluid laden tubing must be pulled from the well. Experience has shown that using a retrievable blanking plug is not a cost effective way to prevent well fluids from entering a tubing string. 
     A sixth problem occurs when running a “pump-out-plug”. The pumped-out portion of the pump-out-plug has an outside diameter greater than the internal diameter of the tubing, and therefore, it may not be circulated out of the well up the tubing. Further, the outside diameter of the pumped-out portion of the pump-out-plug is generally of a dimension that prevents is from being circulated from the well up the tubing/casing annulus. Additionally the pumped-out portion of a pump-out-plug is normally made from a metal, generally aluminum, which will fall on top of any cased-hole tools below the pump-out-plug and prevent them from being pulled from the well at a later date. The metal pumped-out portion may become wedged between the casing internal surface and the outer surface of the cased-hole tools (known as retrievable packers, retrievable bridge plugs, and others). Therefore, in general, pump-out-plugs are only run in a well at the bottom end of a tubing string, sometimes below a retrievable packer, and the pumped-out portion of the pump-out-plug falls into the rat hole at the bottom of the well. Pump-out-plugs are not compatible and with a drill bit. 
     A seventh problem occurs when running a “rupture disk”. A rupture disk is run above the bit and drill collars in the tubing in a tubing nipple or a J-J (the small internal area in a tubing collar between the two pin ends of tubing) to prevent well fluid from entering the tubing when it is run into a well that is full of well fluid. When it is time to establish circulation the tubing is filled with fluid and pressure applied on top of the rupture disk, thereby rupturing it and establishing circulation in the well. The debris left in the J-J or tubing nipple of the rupture disk are protrusions into the internal diameter of the tubing string. These protrusions may hang debris circulated up the tubing and plug it off, causing the operator to pull the work string. Many times surface intervention may be required to pierce the rupture disk to facilitate rupturing it. Experience has shown that the use of a rupture disk is fraught with potential problems and unnecessary expense. 
     An eight problem occurs when lowering tubing into a well with drilling mud that contains lost circulation material, such as cotton seed hulls, walnut chunks, cellophane particles, etc. Experience has shown that the lost circulation material, when entering the bit, may plug it off, or may plug off the tubing above the bit. This situation reminds us that under these circumstances it is generally a good idea to run some type of tubing plugging apparatus. 
     The present invention addresses these problems. A primary object of the present invention is to prevent well fluids from entering the tubing as it is lowered into a well full of fluid. 
     A second object of the invention is to remove the plugging apparatus with well fluids leaving no debris in the tubing. 
     A third object of the invention is to remove the plugging apparatus without surface intervention. 
     A fourth object of the invention is to be able to establish circulation at any time, allowing the operator full control of the well. 
     A fifth object of the invention is to allow the well operator, when pumping out the plugging apparatus, to monitor the tubing pressure at the surface, to identify when the internal bidirectional tubing plug has released by observing a pressure build up and fall off, and then establish that the well is circulating. 
     A sixth object of the invention is to leave the internal diameter of the tubing constant when the plugging apparatus is removed. 
     A seventh object of the invention is to blank off the tubing with very small parts that may be circulated through a workover bit, up the tubing/casing annulus, or through the workover bit up the tubing to the surface. 
     An eighth object of the invention is to manufacture the small parts of this plugging apparatus from material recognized as biodegradable. 
     A ninth object of this invention is to manufacture the internal parts of this plugging apparatus of a material that is sufficient for the pressures and temperatures encountered in most well conditions. 
     A tenth object of this invention is to manufacture the parts of this plugging apparatus from a material that is easily drillable. 
     SUMMARY OF THE INVENTION 
     The invention is an internal bidirectional tubing plug for plugging a well. The plug is housed in a body that connects on its ends to the well&#39;s tubing string. The body has a petal recess for receiving a petal assembly and a cork assembly. Upper and lower pistons are provided on the top and bottom, respectively, of the petal and cork assemblies. 
     The petal assembly consists of several, generally four in number, identical petals that are adjacent each other, fifth and sixth petals that are located adjacent to and on either side of the identical petals, and a seventh or keystone petal that is located between the fifth and sixth petals. The petals jointly form a hole in the petal assembly into which the cork assembly is received. 
     The purpose and function of the internal bidirectional tubing plug is to prevent well fluids from passing the plug in a well conduit, in either direction, within a well until the plug is activated or deconstructed and pumped apart so that the pieces that comprise the plug are either pumped down or up a tubing string or down or up a casing or tubing annulus of the well. 
     As the plug is lowered into the fluid filled well, a hydrostatic pressure pushes against the lower piston which in turn transfers the pressure onto the petal assembly and to an upper lip of the body of the plug. The tapered outside shape of the cork directs additional force onto the petal assembly and the body of the plug. 
     The plug is activated, released or deconstructed by applying hydraulic pressure applied in upper area of the plug. This forces the cork to fail at a recess provided in the cork, allowing the bottom portion of the cork to be pushed out of the bottom of the body along with the lower piston. Once the bottom portion of the cork is gone, hydraulic forces next causes the keystone petal to be forced out of the body, followed by the remaining petals, the upper piston and the nut that holds the broken top of the cork. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view with hidden lines shown of the internal bidirectional tubing pug. 
         FIG. 2  is a front cross section view of  FIG. 1 , except the cork is not shown in cross section. 
         FIG. 3  is a front cross section view of  FIG. 1 , except the nut, cork, and O-ring are not shown in cross section. 
         FIG. 4  is a front cross section view of the body, nut, keystone petal, and upper and lower piston of  FIG. 1 . 
         FIG. 4A  is an enlarged view of the area contained within circle A of  FIG. 4  to shown a close up view of the nut, cork, keystone petal and upper piston. 
         FIG. 5  is a front cross section view of the internal bidirectional tubing plug of  FIG. 1  with the bottom of the failed cork and the lower piston not shown in cross section and showing the failed cork and lower piston being pushed downward out of the plug. 
         FIG. 6  is a front cross section view of the internal bidirectional tubing plug of  FIG. 5  shown with the keystone petal being displaced. 
         FIG. 7  is a front cross section view of the body of the plug after the contents have been flushed down and out of the plug. 
         FIG. 8  is an isometric view of the petal assembly of the plug of  FIG. 1 . 
         FIG. 9  is an isometric view of one of the four identical petals of the petal assembly of  FIG. 8 . 
         FIG. 9A  is a rotated view of the petal of  FIG. 9 . 
         FIG. 10  is an isometric view of the fifth petal of the petal assembly of  FIG. 8 . 
         FIG. 10A  is a rotated view of the fifth petal of  FIG. 10 . 
         FIG. 11  is an isometric view of the sixth petal of the petal assembly of  FIG. 8 . 
         FIG. 11A  is a rotated view of the sixth petal of the  FIG. 11 . 
         FIG. 12  is an isometric view of the keystone petal of the petal assembly of  FIG. 8 . 
         FIG. 12A  is a rotated view of the keystone petal of  FIG. 12 . 
         FIG. 13  is an isometric view of the cork assembly from the plug of  FIG. 1 . 
         FIG. 13A  is a front cross sectional view of the cork assembly of  FIG. 13 . 
         FIG. 14  is a front view of the cork of  FIG. 13  with hidden lines shown. 
         FIG. 15  is an isometric view of the o-ring of the plug of  FIG. 1 . 
         FIG. 15A  is an isometric view of the upper piston of the plug of  FIG. 1 . 
         FIG. 15B  is an isometric view of the lower piston of the plug of  FIG. 1 . 
         FIG. 16  is an enlarged isometric view of the nut of the cork assembly of  FIG. 13 . 
         FIG. 16A  is a rotated view of the nut of  FIG. 16 . 
         FIG. 17  is an isometric view of the assembly device for assembling the plug of  FIG. 1 . 
         FIG. 18  is an isometric view of the assembly device of  FIG. 17  shown with a nut from the cork assembly in place on the assembly device. 
         FIG. 19  is a front cross sectional view of the assembly device, with a nut in place on the assembly device and a body of the plug positioned over the assembly device. 
         FIG. 20  is a top plan view of the assembly device of  FIG. 19  shown with a nut in place on the assembly device and a body of the plug positioned over the assembly device and with all of the petals of the petal assembly in place except for the keystone petal. 
         FIG. 20A  is a front cross sectional view of the assembly device of  FIG. 20 . 
         FIG. 21  is a top plan view of the assembly device of  FIG. 20  with the keystone petal being slipped into place in the petal assembly. 
         FIG. 21A  is front cross section view of the assembly device of  FIG. 21 . 
         FIG. 22  is a front cross section view of the assembly device of  FIG. 21  shown with the cork partially screwed into the nut. 
         FIG. 23  is a front cross section view of the plug shown in  FIG. 22  that has been removed from the assembly device and with the cork fully screwed into the nut and the lower piston inserted into the bottom of the plug. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and initially to  FIGS. 1-3 , there is illustrated an internal bidirectional tubing plug  1  that is constructed in accordance with a preferred embodiment of the present invention. 
     Referring also to  FIG. 7 , the plug  1  is housed in a body  10 . The body  10  has a top  11 , a box connection  12 , an inside diameter  14 , an upper lip  15 , a petal recess  17 , a lower lip  18 , a pin connection  22  and a bottom  20 . Referring to  FIG. 2 , the body  10  of the plug  1  contains a cork assembly  60 , a petal assembly  30 , an upper piston  112 , and a lower piston  113 . 
     Referring to  FIGS. 8-12A , the petal assembly  30  consists of four identical petals  40  that are adjacent each other, a fifth petal  120  that is located adjacent the four identical petals  40 , a sixth petal  130  that is also located adjacent the four identical petals  40 , and a seventh or keystone petal  50  located between the fifth and sixth petals  120  and  130 . The petals  40 ,  120 ,  130 , and  50  jointly form a hole  31  in the petal assembly  30  for receiving the cork assembly  60 . 
     Although the petal assembly  30  is illustrated and described herein as containing four identical petals  40 , the invention is not so limited. Therefore, there may be more or less than four identical petals  40  employed in various embodiments of the invention, depending on the size of the plug  1 . 
     Referring to  FIGS. 9 and 9A , the four identical petals  40  each are provided with a top side  41 , a tapered conical inner surface  43 , an upper edge  44 , a back  45 , a lower edge  46  and a bottom  47 . Referring to  FIGS. 10 and 10A , the fifth petal  120  is provided with a top  121 , sides  122 , a tapered conical inner surface  123 , an upper edge  124 , a back  125 , a lower edge  126 , and a bottom  127 . Referring to  FIGS. 11 and 11A , the sixth petal  130  is provided with a top  131 , sides  132 , a tapered conical inner surface  133 , an upper edge  134 , a back  135 , a lower edge  136  and a bottom  137 . Finally, referring to  FIGS. 12 and 12A , the keystone petal  50  is provided with a top  51 , a tapered conical inner surface  53 , an upper edge  52 , a back  54 , an angled bevel  56  located at a lower end of the back  54 , an inner lip  58 , a bottom  57  and sides  55 . 
     Referring to  FIGS. 13 ,  13 A and  14 , the cork assembly  60  consists of a nut  90 , a cork  70  and an o-ring  80 . The cork  70  has a top  71 , threads  72 , a recess  73 , a fluid groove  74 , a tapered outside frusto-conical surface  75 , an o-ring groove  76 , a bottom  77 , and a slot  78  used to screw the cork  70  into the nut  90 , as will be described more fully hereafter. 
     The o-ring  80  which is illustrated in  FIG. 15  is received in the o-ring groove  76  of the cork assembly  60 , as shown in  FIG. 14 . Also, the upper and lower pistons  112  and  113 , which are shown in  FIGS. 15A and 15B , respectively, attached to the top and bottom, respectively, of the petal assembly  30 . 
     Referring for  FIGS. 16 and 16A , the nut  90  is provided with threads  92  that match in mating fashion with the threads  72  of the cork  70 . The slots  94  in the nut  90  direct hydraulic pressure to the fluid groove  74  of the cork  70 . The bottom  95  of the nut  90  rests against the top of the petal assembly  30  of the plug  1 , as best shown in  FIGS. 2 and 4A . 
     The purpose and function of the internal bidirectional tubing plug  1  is to prevent well fluids from passing the plug  1  in a well conduit, in either direction, within a well until the plug  1  is activated and pumped apart so that the pieces that comprise the plug are either pumped either down or up a tubing string or down or up a casing or tubing annulus of the well as will be more fully explained hereafter. 
     The pin connection  22  of the body  10  screws into a tubing string (not illustrated) which generally is above the bit and drill collars, and a pin connection (not illustrated) of the tubing string screws into the box connection  12  of the plug  1 . The tubing and the attached plug  1  are then lowered into the fluid filled well and the plug  1  prevents well fluid from entering the tubing. Although not illustrated, as the tubing is lowered into the well, the tubing&#39;s outside volume is displaced up the tubing/casing annulus against a stripper rubber and displaced well fluids are forced out of the well through a casing valve to a pit. 
     As the plug  1  is lowered into the fluid filled well, a hydrostatic pressure is developed in lower area  111  within the body  10 , as seen in  FIG. 3 , generating a force which acts against the lower piston  113 , which in turn acts upon the bottoms  47  of the four identical petals  40 , upon the bottom  57  of the keystone petal  50 , upon the bottom  127  of the fifth petal  120 , upon the bottom  137  of the sixth petal  130 , and upon the bottom  77  of the cork  70  which transfers this force into the upper lip  15  of the body  10 . In addition, the force generated on the bottom  77  of the cork  70  due to the tapered outside frusto-conical surface  75  of the cork  70  directs the vertical and horizontal components of the force generated on the cork  70  through the four identical petals  40 , through the fifth petal  120 , through the sixth petal  130 , and through the keystone petal  50  outward into the petal recess  17  of the body  10  and upward into the upper lip  15  of the body  10 . 
     The release or activation of the plug  1  will now be described. Once the tubing and plug  1  reach working depth, well fluids are pumped into the tubing string to equalize the hydrostatic pressure across the plug  1  from the top  11  to the bottom  20  of the body  10 . To release the plug  1 , hydraulic pressure in the form of extra hydrostatic pressure or applied hydraulic pressure at the well surface is applied in upper area  110  of the plug  1 . Some wells don&#39;t stand full of fluid and just dumping enough fluid above them, filling the tubing to a sufficient level of fluid will generate enough hydrostatic or hydraulic pressure to release the plug. Other wells are full and the operator will have to apply pump pressure at the surface to pump the plug loose. 
     As shown in  FIGS. 4 and 4A , applied hydraulic pressure acts through fluid path  114 , that exerts hydraulic pressure on an area as defined by outside diameter of o-ring  80 , that exerts a downward force opposing an upward force defined by the area of the recess  73  of the cork&#39;s outside diameter and by the mechanical properties of the material from which the cork  70  is constructed and which is held by the nut  90 . When the downward forces exceed the upward forces, the cork  70  fails in tension at the recess  73 , thereby allowing the bottom portion  79  of the cork  70  to move downward after it fails. The bottom portion  79  of the cork  70  is that portion of the cork  70  located below the recess  73  which parts from the rest of the cork  70  that remains above the petal assembly  30  after the cork  70  fails. 
     As illustrated in  FIG. 5 , once the cork  70  has parted, well fluids from above the plug  1  displace the bottom portion  79  of the cork  70  and the lower piston  113  downward and away from the petal assembly  30 . 
     Referring also to  FIG. 6 , after the bottom portion  79  of the cork  70  has been displaced from the petal assembly  30 , fluid flow through the hole  31  in the petal assembly  30  generates a differential pressure across the petals  40 ,  50 ,  120 , and  130  of the petal assembly  30 . This differential pressure acts on the upper surface or top  51  of the keystone petal  50 , generating a downward force that forces the keystone petal  50  inward out of the body recess due to its bevel  56  and downward out of the petal assembly  30 . The inner lip  58  of the keystone petal  50  has an inside diameter this is less than the inside diameter  14  of the body  10 . This allows the bevel  56  of the keystone petal  50  to ride against the inside diameter  14  of the body  10 , forcing the keystone petal  50  downward and inward and ultimately out of the petal assembly  30 . This leaves a space or gap in the petal assembly  30  where the keystone petal  50  had been. This resulting space and fluid flow through the remainder of the petal assembly  30  allows the remaining petals  40 ,  120 , and  130  of the petal assembly  30  to be swept downward in cascading fashion and out of the petal recess  17  of the body  10 , leaving only the open body  10  as shown in  FIG. 7 . 
     Referring now to  FIGS. 17-23 , initial assembly of the plug  1  will be described. In order to initially assembly the plug  1  for use, it is necessary to employ an assembly device  100 . As shown in  FIG. 17 , the assembly device  100  consists of a base plate  105  having a top  107 , sides  106 , and a center post  103  oriented perpendicular to the base plate  105 . The top  101  of the post  101  is provided with a nut socket  102  that receives the nut  90  therein. 
     To assembly the plug  1 , first the nut  90  is inserted into the nut socket  102  of the assembly device  100  so that the slots  94  of the nut  90  are facing up, as shown in  FIG. 18 . Next, as illustrated in  FIG. 19 , the top  11  of the body  10  is placed over the post  101  and is lowered down against the top  107  of the base plate  107 . 
     Then, as illustrated in  FIGS. 20 and 20A , the tops  41  of the four identical petals  40  are sequentially inserted through the bottom  20  of the body  10  and then through the inside diameter  14  of the body  10  until the tops  41  of the petals  40  are in contact with the top  101  of the post  103  of the assembly device  100 . Then the petals  40  are pushed outward until their backs  45  are in contact with the recess  17  of the body  10  and the upper edges  44  and the lower edges  46  of petals  40  are in contact with the upper lip  15  and lower lip  18 , respectively, of the body  10 . Each of the four petals  40  are inserted in this manner sequentially, with a side  42  of each petal  40  is placed in contact with a side  42  of the previously inserted petal  40  until all four petals  40  are inserted into the body  10 . 
     Then the fifth and sixth petals  120  and  130  are likewise inserted into the body  10  on either side of the four adjacent petals  40  and are adjusted to leave room between the fifth and sixth petals  120  and  130  for the keystone petal  50  to be inserted there between. This assembly, when finished, will create the hole  31  in the petal assembly  30  for receiving the cork  70 . 
     Finally, as illustrated in  FIGS. 21 and 21A , the top  51  of the keystone petal  50  is inserted through the bottom  20  of the body  10  and through the inside diameter  14  of the body  10  until the top  51  of the keystone petal  50  is in contact with the top  101  of the post  103  of the assembly device  100  which places the sides  55  of the keystone petal  50  in sliding contact with the side  122  of the fifth petal  120  and with the side  132  of the sixth petal  130 . The back  54  of the keystone petal  50  slides down the inside diameter  14  of the body  10  until the bottom  57  of the keystone petal  50  is in contact with the top  101  of the post  103  of the assembly device  100 , through the hole  31  in the petal assembly  30 . Next, the back  54  of the keystone petal  50  is pushed outward until the back  54  is in contact with the recess  17  of the body  10 . 
     As shown in  FIG. 22 , the top  71  of the cork  70  is then inserted through the bottom  20  and the inside diameter  14  of the body  10  until the threads  72  of the cork  70  engage the threads  92  of the nut  90 . The cork  70  is then rotated by a screw driver device (not shown) that inserts into slot  78  of the cork  70  until the bottom  77  of the cork  70  is even with the bottoms  47  of the petals  40 . Next, as shown in  FIG. 23 , the top  11  of the body  10  is removed from the assembly device  100  and is placed on a flat surface. A lower piston  113  is then attached to the bottoms  47 ,  57 ,  127 , and  137  of the petals  40 ,  50 ,  120 , and  130  and the bottom  77  of the cork  70  by friction fit. The body  10  is then rotated 180 degrees so that the bottom  20  of the body  10  rests on a flat surface. The upper piston  112  is then attached to the tops  41 ,  51 ,  121 , and  131  of the petals  40 ,  50 ,  120 , and  130  in a similar manner. 
     While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and the arrangement of components without departing from the spirit and scope of this disclosure. It is understood that the invention is not limited to the embodiments set forth herein for the purposes of exemplification, but is to be limited only by the scope of the attached claim or claims, including the full range of equivalency to which each element thereof is entitled.