Abstract:
A mud saver valve, positionable at the bottom of the drill string, above the bit, which includes an elongated body portion; portion of the valve housing a compressible spring a pressure; a valve mechanism which is a sliding sleeve moveable between open and closed positions within the valve; while in the closed position, drilling fluid cannot pass through the valve; when a combination of static and pump pressure exceeds the setting pressure of the dome, the sleeve will be moved by actuation pistons to the open position, at which drilling fluid is allowed to through the valve. Also, wherein when the valve is normally closed, as long as the fluid column pressure is less than the setting pressure, the valve remains closed, and allows the drill string to be disconnected and a section of pipe can added without the fluid draining from the drill column above the bit, and thus saving fluid.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Priority of U.S. Provisional Patent Application Ser. No. 61/320,037, filed 1 Apr. 2010, incorporated herein by reference, is hereby claimed. 
    
    
     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 oilfield valves. More particularly, the present invention relates to a mud saver valve when installed to prevent the loss of drill fluid during starting operation in deep water wells using a combination of static fluid pressure and flow pressure to open the valve and mechanical spring forces to close the valve. 
     2. General Background of the Invention 
     When drill pipe and other tubular strings are lowered into or raised out of a well bore, including, but not limited to, during the drilling of the wellbore, it is quite common, particularly in the oil and gas field, for the drill pipe and other tubular strings to be filled with mud of the type used in drilling techniques. The mud would typically be pumped into the upper end of the drill string after it has been connected to the drill string below it and/or as it is being lowered into a wellbore. As the next joint is added to the drill string, the connection is typically disconnected from the drill string to allow the next section of drill pipe to be connected to the string. When the fluid connection is disconnected, there should preferably to be a mud saver valve in place to retain this fluid and prevent it from flowing out onto the work area and environment. The advantages of using such a valve are well known and include saved mud cost, decreased chances of pollution, and increased safety to rig personnel. To avoid this loss of mud during these types of operations there is needed a mud saver valve which could be positionable just above the drilling bit or just below the bend sub to prevent the loss of drill fluid during starting operation in deep water wells, which reduces the amount of drilling fluid required to start a well and reduces the pollution of the mud bottom with drilling fluid and weighting material. 
     This invention replaces the original Mud Saver Valve, as disclosed U.S. patent application Ser. No. 12/652,547, noted above, which utilized a pre charged nitrogen dome chamber to feed pre charge pressure to the closing side of multiple pistons that are arranged in an equally spaced circular pattern around the center axis of the valve. The force created by the pre charge pressure acting on the multiple pistons force a slidable sleeve to close the fluid pathway through the valve. 
     To force the original Mud Saver Valve to open its fluid pathway through the valve, pressure inside the drill pipe at the valve&#39;s location in the well bore has to rise above the pre charge pressure of the nitrogen dome plus whatever pressure is required to overcome the friction force of the piston seals. To accomplish this either direct hydrostatic head pressure or the combination of direct hydrostatic head pressure and flow pressure generated by the mud pumps are required. 
     With the original Mud Saver Valve the amount of pump pressure required to open the valve is a function of the depth of the tool in the well bore. The deeper the tool, the higher the hydrostatic head pressure and the lower the pump pressure required to open the valve. 
     With the original Mud Saver Valve the valve could be set to open at any particular depth by adjusting the nitrogen pre charge pressure prior to entering the well bore. 
     The following U.S. patents are incorporated herein by reference: 
     
       
         
               
               
               
             
           
               
                 TABLE 
               
               
                   
               
               
                 U.S. Pat. No./ 
                   
                 ISSUE DATE 
               
               
                 Publication No. 
                 TITLE 
                 DD-MM-YYYY 
               
               
                   
               
             
             
               
                 20030102131 
                 Mudsaver Valve with retrievable 
                 06-05-2003 
               
               
                   
                 inner sleeve. 
                   
               
               
                 20050189144 
                 Mud Saver Valve 
                 09-02-2005 
               
               
                 20050236191 
                 Drill String Valve Assembly 
                 10-27-2005 
               
               
                 20010037900 
                 Mud Saver Kelly Valve 
                 11-08-2001 
               
               
                 20070039759 
                 Mud Saver Valve 
                 02-22-2007 
               
               
                 7,048,079 
                 Mud Saver Valve 
                 05-23-2006 
               
               
                 6,053,191 
                 Mud-Saver Valve 
                 04-25-2000 
               
               
                 6,640,824 
                 Mud Saver Kelly Valve 
                 11-04-2003 
               
               
                 6,662,886 
                 Mudsaver Valve with Dual Snap 
                 12-16-2003 
               
               
                   
                 Action 
               
               
                   
               
             
          
         
       
     
     BRIEF SUMMARY OF THE INVENTION 
     The mud saver valve of the present invention solves the problems in the art in a simple and straightforward manner. 
     In summary, the new Mud Saver Valve II replaces the nitrogen dome with a mechanical compression spring that is compressed during the valve assembly process to a certain pre load found in the original Mud Saver Valve discussed above. This mechanical spring pre load provides the closing force acting on the valve&#39;s Mud Saver Valve II also opens the closing side of the multiple pistons to the annulus pressure at the valve location depth in the well bore. 
     Further, as with the original Mud Saver Valve, the opening side of the multiple pistons are fed with the pressure in the drill pipe at the valve&#39;s location depth in the well bore. 
     Further, in a static condition without flow if the fluid mud in the annulus and the fluid mud in the drill pipe are the same weight per unit volume then (neglecting friction in the piston seals) the differential pressure working across the multiple actuator pistons is zero. 
     The new pump pressure required to open the new Mud Saver Valve II is no longer a function of the depth of the valve in the well bore. The pump pressure required to open the new Mud Saver Valve II, at any well bore depth, is only a function of the mechanical compression spring pre load and whatever pressure is required to overcome the friction of the piston seals. 
     In the new Mud Saver Valve II design the amount of friction of the piston seals can be dramatically reduced by converting to mechanical labyrinth type seal. Labyrinth seals have no physical contact between the sealing surfaces. As a consequence of this the friction of the seal is eliminated. However, a small amount of leakage will pass through the seal. The amount of fluid following through the valve can be 12 barrels per min. (504 gal./min (1908 Liters/min)). The small amount of leakage past the two (2) 0.625 inch (1.59 cm) diameter pistons is thought to be negligible. 
    
    
     
       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: 
         FIG. 1  is a trimetric view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 2  is a front view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 3  is a front section view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 4  is a front section view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 5  is a front section view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 6  is a front section view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 7  is a front section view—Valve Actuator Piston—Seal Assembly 
         FIG. 8  is a top view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 9  is a front view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 10  is an isometric view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 11  is a front section view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 12  is a front section view of the preferred embodiment of the apparatus of the present invention; 
         FIG. 13  is a front section view of the preferred embodiment of the apparatus of the present invention in the closed position; 
         FIG. 14  is a front section view of the preferred embodiment of the apparatus of the present invention in the open position; 
         FIG. 15  illustrates an isometric view of an alternate embodiment of the Mud Saver Valve II of the present invention; 
         FIG. 16  illustrates a front view of an alternate embodiment of the Mud Saver Valve II of the present invention; 
         FIG. 17  illustrates a front section view in the close of the alternate embodiment of the Mud Saver Valve II in the closed position; 
         FIG. 18  illustrates a front section view of an alternate embodiment of the Mud Saver Valve II illustrating the major sub assemblies; 
         FIG. 19  illustrates a front section view of the alternate boxed end sub pre assembly of the Mud Saver Valve II of the present invention; 
         FIG. 20  illustrates a front section view of an alternate valve actuator pre assembly of the Mud Saver Valve II of the present invention; 
         FIG. 21  illustrates a front section view of the alternate pin end sub pre assembly of the Mud Saver Valve II of the present invention; 
         FIG. 22  illustrates a front section view (cut) of the Mud Saver Valve II of the present invention in the closed position; and 
         FIG. 23  illustrates a front section view (cut) of the Mud Saver Valve II in the open position. 
         FIGS. 24 and 25  illustrate modified embodiments of the Mud Saver Valve II of the present invention from that shown in  FIGS. 22 and 23 . 
         FIG. 26  illustrates an alternate embodiment of the mud saver valve II of the present invention with the drill bit and drill string or pipe shown in phantom view. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 through 25  illustrate the embodiments of the Mud Saver Valve III of the present invention. 
     Prior to a discussion of the drawing figures, it should be kept in mind that the overall function of the Mud Saver Valve II and Mud Saver Valve with Concentric Pistons is the same as the original Mud Saver. 
     When the rig&#39;s mud pumps that circulate mud down the drill pipe to the drill bit at the bottom of the well bore and then return the mud, contaminated with drilled shavings, up the annulus to the BOP stack and finally either take the returning mud up the (subsea riser/spool) or (choke/kill lines) are off, a mechanical device in the original Mud Saver Valve and modified mechanical devices in the Mud Saver Valve II and Mud Saver Valve with Concentric Pistons force these valves to their closed positions and do not allow mud to flow through them. 
     When the rig&#39;s mud circulating pumps are turned on pressures working on respective mechanical devices in each of these three (3) Mud Saver Valve designs force the valves to open and allow the mud to flow through the valves. 
     The overall function of these valves is to capture the large volume of conditioned clean mud that is in the drill pipe from just above the drill bit at the bottom of the well bore up to the rig floor. These Mud Saver Valves will not allow the clean mud in the drill pipe to drain out of the bottom of the pipe and into the contaminated mud in the annulus as individual pipe stands are tripped in and out of the well bore. 
     The original Mud Saver Valve uses a pre charged nitrogen dome chamber to feed pre charge pressure to the closing side of multiple pistons that are arranged in an equally spaced circular pattern around the center axis of the valve. The force created by the pre charge pressure acting on the multiple pistons force a slidable sleeve to close the fluid pathway through the valve. 
     To force the original Mud Saver Valve to open its fluid pathway through the valve, pressure inside the drill pipe at the valve&#39;s location in the well bore has to rise above the pre charge pressure of the nitrogen dome plus whatever pressure is required to overcome the friction force of the piston seals. To accomplish this either direct hydrostatic head pressure or the combination of direct hydrostatic head pressure and flow pressure generated by the mud pumps are required. 
     With the original Mud Saver Valve the amount of pump pressure required to open the valve is a function of the depth of the tool in the well bore. The deeper the tool, the higher the hydrostatic head pressure and the lower the pump pressure required to open the valve. 
     With the original Mud Saver Valve the valve could be set to open at any particular depth by adjusting the nitrogen pre charge pressure prior to entering the well bore. 
     The new Mud Saver Valve II replaces the nitrogen dome with a mechanical compression spring that is compressed during the valve assembly process to a certain pre load. This mechanical spring pre load provides the closing force acting on the valve&#39;s Mud Saver Valve II also opens the closing side of the multiple pistons to the annulus pressure at the valve location depth in the well bore. 
     As with the original Mud Saver Valve, the opening side of the multiple pistons are fed with the pressure in the drill pipe at the valve&#39;s location depth in the well bore. 
     In a static condition without flow if the fluid mud in the annulus and the fluid mud in the drill pipe are the same weight per unit volume then (neglecting friction in the piston seals) the differential pressure working across the multiple actuator pistons is zero. 
     The new pump pressure required to open the new Mud Saver Valve II is no longer a function of the depth of the valve in the well bore. The pump pressure required to open the new Mud Saver Valve II, at any well bore depth, is only a function of the mechanical compression spring pre load and whatever pressure is required to overcome the friction of the piston seals. 
     In the new Mud Saver Valve II design the amount of friction of the piston seals can be dramatically reduced by converting to mechanical labyrinth type seal. Labyrinth seals have no physical contact between the sealing surfaces. As a consequence of this the friction of the seal is eliminated. However, a small amount of leakage will pass through the seal. The amount of fluid following through the valve can be 12 barrels per min. (504 gal./min (1908 liters/min)). The small amount of leakage past the two (2) 0.625 inch (1.59 cm) diameter pistons is thought to be negligible. 
     Turning now the drawing Figures, first  FIG. 13  illustrates the new Mud Saver Valve II in the closed position. Spring  24  is the closing compression spring that is preloaded at assembly and pushes against a spring closing sleeve  23  which ultimately pushes against valve actuator-sliding sleeve (open/close)  32  and closes the valve. 
     The annulus pressure is fed through annulus pressure feed port  3  to the closing side of valve actuator-piston  34  at valve actuator-piston close valve pressure side  42 . 
     The pressure inside the drill string or pipe  17  which with the same weight fluid in the pipe  17  and annulus is equal to the annulus pressure is fed down inlet fluid conductor  6  to the valve actuator radial port through valve actuator radial port  7  and into inlet fluid cavity between the valve actuator housing and the valve actuator sliding sleeve  8 , where it is blocked by sliding sleeve  32  and fed to valve actuator-piston open valve pressure side  41 . Since the annulus and pipe pressure are equal the differential pressure across the pistons  34  is zero and the springs  24  pre load holds the valve closed. 
       FIG. 14  illustrates the new Mud Saver Valve II in the open position. Fluid is shown flowing through the valve. At the moment when the mud pumps are turned on and sliding sleeve  32  is in the closed position, as shown in  FIG. 13 , pressure builds quickly at valve actuator  41  which moves inlet fluid piston  34  to the open position. Fluid flows down inlet fluid conductor  6  and then through valve actuator radial port  7  where it enters inlet fluid cavity between the valve actuator housing and the valve actuator sliding sleeve  8  before flowing through cage radial inlet ports  55  and entering the orifice inlet  56 . The flow across the orifice  52  creates a pressure differential across the orifice item  52 . For all practical purposes the pressure differential across the orifice  52  is approximately equal to the pressure differential across the piston  34 . The pressure at orifice inlet  56  is approximately equal to the pressure at actuator-actuator-piston open  41 . The pressure at orifice outlet  57  is approximately equal to the pressure at valve actuator-piston close  42 . Practically, the orifice can be considered to be anything from valve actuator-piston open  41  through the drill bit  83  that creates any pressure drop (restrictions). High flow rates with high pressure drop will insure that the valve stays completely open. If the flow rate drops the valve will throttle itself working the pressure differential across the piston  34  against the spring preload  24 . 
     From Alternate Embodiment Operation 
     Recent testing of the Mud Saver Valve II, as represented in  FIGS. 1-14  performed as expected. At a very low flow rate (less than 1 gal/min (3.78 liters/min)) the Mud Saver Valve II cracked open at the correct pressure and then repeatedly closed and re-cracked open as expected. However, there are a couple of points which we would like to cover as an alternate embodiment of the Mud Saver Valve II and represented in  FIGS. 15-23 . 
       FIGS. 15-17  and  26  illustrate an alternate embodiment  60  of the Mud Saver Valve II. A box end pre-sub assembly  70 , and annulus pressure feed port  71  which is kidney shaped, are shown.  FIG. 18  illustrates the major sub assemblies, including the box and pre-sub assembly  70 , valve components  80 ,  90 , and valve actuator housing  40 .  FIG. 26 , shows the alternate embodiment of the Mud Saver Valve II, positioned on the drill string or pipe  17 , just above drill bit  83 . 
     The first area of interest is the two (2) small pistons represented in  FIGS. 1-14 . There is no guarantee that both small pistons will function in the exact same way. If one piston should hang up, for what ever reason, it may cause the valve to cock and stick. Also, the cross sectional area of the two (2) pistons is very small and therefore requires a fairly high cracking pressure even though the closing spring pre load force is relatively low at 600 pounds (272 kg). The high crack pressure is wasted pressure that gets added to the pump pressure requirements as the valve is throttled between the fully closed and fully opened positions. 
     Piston  74 ,  84  of  FIG. 17 . In the alternate embodiment the two (2) small pistons that were positioned radially offset from the center axis of the valve are replaced with these two (2) much larger piston that are positioned concentrically with the center axis of the valve and each other. The new pistons are also concentric with other important valve components such as reference  80 ,  90 , shown more clearly in  FIG. 18 . 
     This design represented in  FIG. 17  will allow for a much lower cracking pressure and much higher spring pre load closing force. Also if cast iron piston seal or Teflon split piston seals are used they will provide very low friction forces and high ware resistance. However these seals will allow a very small amount of fluid to leak past them. 
     The second area of interest is the Pin End (bottom) Sliding Sleeve Seal represented as sliding sleeve main seal  33  of  FIG. 6 . Reference is made to  FIG. 13  and  FIG. 14  showing the valve in the closed and open position. Notice that as the valve opens the Pin End (bottom) Sliding Sleeve Seal must pass over the radial ports in the cage represented as cage radial inlet ports  55  of  FIG. 14 . Also notice that the Box End (top) Sliding Sleeve Seal is Ok as it never passes over the radial ports. 
     The Pin End (bottom) Sliding Sleeve Seal may be cut or otherwise damaged as it passes over the radial ports. The relatively low closing force of the spring may not allow the valve to close if part of the damaged seal gets caught up in the Sliding Sleeve mechanism. 
     In the alternate embodiment the Pin End (bottom) Sliding Sleeve Seal is made larger in diameter and moved to an alternate embodiment of the Cage. Reference  FIG. 21 , reference  93 , alternate Cage (Plunger Type), represents the new larger Sliding Sleeve Seal, reference  91  of  FIG. 21  and the snap ring and back up washer, reference  92  of  FIG. 21 , that is used to hold the seal in place. 
     The new alternate embodiment of the Sliding Sleeve, alternate valve actuator-sliding sleeve (Open/close)  82  of  FIG. 20  has a very gradual tapered nose which is designed to function as a plunger that slides in under the new larger seal, Reference  91  of  FIG. 21 . 
       FIG. 22  shows the new Mud Saver Valve w/Concentric Pistons in the closed position. Spring  24  is the closing compression spring that is pre loaded at assembly and pushes against alternate Spring Closing Sleeve  77  which ultimately pushes against alternate valve actuator-sliding sleeve (Open/close)  82  and closes the valve. 
     The annulus pressure is fed through Alternate Annulus Pressure Feed Port-Kidney Shaped  71  at Valve Actuator-Piston Close Valve Pressure Side  42 . 
     The pressure inside the pipe which with the same weight per unit volume of fluid in the pipe and annulus is equal to the annulus pressure is fed down Inlet Fluid Conductor  6  to the Valve Actuator Radial Port  7  and into Inlet Fluid Cavity  8  between the Valve Actuator Housing  40  and the Valve Actuator Sliding Sleeve  82  where it is blocked by alternate valve actuator-sliding sleeve (open/close)  82  and fed to Valve Actuator-Piston Open Valve Pressure Side  41 . 
     Since the mud pumps are turned off and the fluid in the pipe has the same weight per unit volume as the fluid in the annulus then the pipe and annulus pressures are equal and the differential pressure across the pistons  84 ,  74  is zero and the pre load force of the spring  24  holds the valve closed. 
       FIG. 23  shows the new Mud Saver Valve with Concentric Pistons in the open position. At the moment the mud pumps are turned on the fluid in the pipe is blocked from flowing by sliding sleeve  82  shown in the closed position in  FIG. 22 . Very quickly pressure builds at valve actuator  41 . When the pressure at valve actuator  41  rises high enough above the annulus pressure at valve actuator  42  to over come the spring per load force provided by spring  24  the pistons  84 ,  74  will move together to open a fluid pathway through the valve. 
     Fluid flows down inlet fluid conductor  6  and then through the radial ports  7  where the fluid then enters inlet fluid cavity  8  before flowing through Cage Radial Ports  55  and entering The Orifice Inlet  56 . The flow across Fixed Orifice  52  creates a pressure differential across Fixed Orifice  52 . For all practical purposes the pressure differential across fixed orifice  52  is approximately equal to the pressure differential across pistons  84 ,  74 . The pressure at Orifice Inlet  56  is approximately equal to the pressure at valve actuator-piston open  41  and the pressure at Orifice Outlet  57  is approximately equal to the pressure at valve actuator-piston close  42 . 
     Practically the Orifice can be considered to be anything from valve actuator-piston open  41  through the drill bit  83  that creates any pressure drop (restriction). High flow rates with high pressure drops will insure that the valve stays completely open. If the flow rate drops the valve will throttle itself working the pressure differential across the pistons  84 ,  74  against the spring preload of spring  24 . 
       FIGS. 24 and 25  illustrate an alternative embodiment of the valve  60  as that shown in  FIGS. 22 and 23  as discussed above. To allow for greater flow capacity, in this embodiment, the cage radial inlet ports  55  are being removed and there are installed fluid guide noses to help the fluid flow entering and leaving inlet fluid cavity  8  between the valve actuator housing and the valve actuator sliding sleeve. The valve actuator-sliding sleeve main seal  33  is also removed. The seal  91  can represent metal to metal conical sealing surfaces, and a vertical face type seal could be employed. 
     Finally, if the fluid in the drill string or pipe  17  and the fluid in the annulus have the same weight per unit volume then the cracking pressure of the valve at any depth is equal to the cracking pressure of the valve at sea level. Therefore, there is no longer a concern about the valve opening because the hydrostatic pressure due the tool&#39;s depth and the weight of the fluid per unit volume in the pipe exceeded the spring cracking pressure. 
     The following is a list of parts and materials suitable for use in the present invention. 
     
       
         
               
             
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
             
          
           
               
                 Part Number 
                 Description 
               
               
                   
               
               
                  1 
                 inlet fluid port at box 
               
               
                  2 
                 outlet fluid port at pin 
               
               
                  3 
                 annulus pressure feed port 
               
               
                  4 
                 mud saver valve II (closed position) 
               
               
                  5 
                 mud saver valve II (open position) 
               
               
                  6 
                 inlet fluid conductor to the valve actuator radial port 
               
               
                  7 
                 valve actuator radial port 
               
               
                  8 
                 inlet fluid cavity between the valve actuator housing and 
               
               
                   
                 the valve actuator sliding sleeve 
               
               
                  9 
                 outlet fluid flow conductor 
               
               
                 10 
                 mud saver valve II - final assembly 
               
               
                 17 
                 drill string/pipe 
               
               
                 20 
                 box end sub pre assembly 
               
               
                 21 
                 box end adaptor 
               
               
                 22 
                 static seal - a 
               
               
                 23 
                 spring closing sleeve 
               
               
                 24 
                 spring 
               
               
                 25 
                 valve actuator piston honed and polished bore 
               
               
                 30 
                 valve actuator pre assembly 
               
               
                 31 
                 valve actuator - upper cage 
               
               
                 32 
                 valve actuator - sliding sleeve (open/close) 
               
               
                 33 
                 valve actuator - sliding sleeve main seal 
               
               
                 34 
                 valve actuator - piston 
               
               
                 35 
                 valve actuator - piston seal assembly 
               
               
                 35a 
                 valve actuator - piston seal end 
               
               
                 35b 
                 valve actuator - piston seal female back up 
               
               
                 35c 
                 valve actuator - piston seal ‘v’ ring - a 
               
               
                 35d 
                 valve actuator - piston seal ‘v’ ring - b 
               
               
                 35e 
                 valve actuator - piston seal center spacer 
               
               
                 36 
                 valve actuator - packing header ring 
               
               
                 37 
                 valve actuator - snap ring 
               
               
                 38 
                 valve actuator - sliding sleeve main seals spacer 
               
               
                 39 
                 valve actuator - optional piston w/labyrinth groove seal 
               
               
                 40 
                 valve actuator housing 
               
               
                 41 
                 valve actuator - piston open valve pressure side 
               
               
                 42 
                 valve actuator - piston close valve pressure side 
               
               
                 50 
                 pin end sub pre assembly 
               
               
                 51 
                 pin end adaptor 
               
               
                 52 
                 fixed orifice 
               
               
                 53 
                 static seal b 
               
               
                 54 
                 cage 
               
               
                 55 
                 cage radial inlet ports 
               
               
                 56 
                 orifice inlet 
               
               
                 57 
                 orifice outlet orifice outlet 
               
               
                 60 
                 alternate mud saver valve II 
               
               
                 70 
                 alternate box end sub pre assembly 
               
               
                 71 
                 alternate annulus pressure feed port-kidney shaped 
               
               
                 74, 84 
                 pistons 
               
               
                 77 
                 alternate spring closing sleeve 
               
               
                 80, 90 
                 valve components 
               
               
                 82 
                 alternate valve actuator-sliding sleeve (open/close) 
               
               
                 83 
                 drill bit 
               
               
                 91 
                 seal 
               
               
                   
               
             
          
         
       
     
     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.