Abstract:
An improved travelling valve, which provides improved qualities of wear resistance, efficiency, and gas lock prevention. The improved travelling valve has a ball which is positioned on a seal stem, so that the ball is reliably centered when seated on the valve seat—reducing damage to the ball and seat from improper seating and providing increased efficiency for deviated or non-vertical pumping operations and the pumping of highly viscous fluids such as heavy crude. In the preferred embodiment, the improved travelling valve is constructed so that a lower portion of the valve rotates during pumping, and thereby imparts rotational movement to the fluid passed therethrough. Such rotational movement of the valve and fluid helps reduce gas lock, and reduces damage to the ball, seat, and valve exterior from impurities in the pumped fluid. Preferably, rotational movement is caused by angled channels in an interior portion of a vein rotator positioned at the bottom of the travelling valve, working in combination with angled channels in the seal stem.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of Invention  
           [0002]    This invention relates generally to oil pumps and travelling valves used therein, and more specifically, to an improved travelling valve providing benefits in the areas of gas lock prevention, wear resistance, and efficiency.  
         BACKGROUND OF THE INVENTION  
         [0003]    In general terms, an oil well pumping system begins with an above-ground pumping unit, which creates the up and down pumping action that moves the oil (or other substance being pumped) out of the ground and into a flow line, from which the oil is taken to a storage tank or other such structure.  
           [0004]    Below ground, a shaft is lined with piping known as “tubing.” Into the tubing is inserted a sucker rod, which is ultimately, indirectly, coupled at its north end to the pumping unit. The sucker rod is coupled at its south end, indirectly, to the oil pump itself—which is also located within the tubing, which is sealed at its base to the tubing. The sucker rod will couple to the oil pump at a coupling known as a 3-wing cage.  
           [0005]    Beginning at the south end, oil pumps generally include a standing valve, which has a ball therein, the purpose of which is to regulate the passage of oil (or other substance being pumped) from downhole into the pump—allowing the pumped matter to be moved northward out of the system and into the flow line, while preventing the pumped matter from dropping back southward into the hole. Oil is permitted to pass through the standing valve and into the pump by the movement of the ball off of its seat, and oil is prevented from dropping back into the hole by the seating of the ball.  
           [0006]    North of the standing valve, coupled to the sucker rod, is a travelling valve. The purpose of the travelling valve is to regulate the passage of oil from within the pump northward in the direction of the flow line, while preventing the pumped oil from dropping back in the direction of the standing valve and hole.  
           [0007]    Actual movement of the pumped substance through the system will now be discussed. Oil is pumped from a hole through a series of “downstrokes” and “upstrokes” of the oil pump, which motion is imparted by the above-ground pumping unit. During the upstroke, formation pressure causes the ball in the standing valve to move upward, allowing the oil to pass through the standing valve and into the barrel of the oil pump. This oil will be held in place between the standing valve and the travelling valve. In the travelling valve, the ball is located in the seated position. It is held there by the pressure from the oil that has been previously pumped. The oil located above the travelling valve is moved northward in the direction of the 3-wing cage at the end of the oil pump.  
           [0008]    On the downstroke, the ball in the travelling valve unseats, permitting the oil that has passed through the standing valve to pass therethrough. Also during the downstroke, the ball in the standing valve seats, preventing the pumped oil from moving back down into the hole.  
           [0009]    The process repeats itself again and again, with oil essentially being moved in stages from the hole, to above the standing valve and in the oil pump, to above the travelling valve and out of the oil pump. As the oil pump fills, the oil passes through the 3-wing cage and into the tubing. As the tubing is filled, the oil passes into the flow line, from which the oil is taken to a storage tank or other such structure.  
           [0010]    There are a number of problems that are regularly encountered during oil pumping operations. Oil that is pumped from the ground is generally impure, and includes water, gas, and impurities such as sand. The presence of gas in the oil can create during pumping operations a condition that is sometimes referred to as “gas lock.” Gas lock occurs when a quantity of gas becomes trapped between the travelling valve and standing valve balls. In this situation, hydrostatic pressure from above the travelling valve ball holds it in a seated position, while the pressure from the trapped gas will hold the standing valve ball in a seated position. With the balls unable to unseat, pumping comes to a halt.  
           [0011]    The typical response to gas lock is to remove the oil pump and release the trapped gas. This can be time-consuming and, of course, interrupts pumping operations.  
           [0012]    Another problem is related to the ball and seat for the ball within the travelling valve. During pumping operations, the ball is continuously being lifted off the seat, rotating, and reseating. However, because the travelling valve ball is not coupled to the seat, it does not always perfectly center when seating. This can result in some leakage in the travelling valve and thus pumping inefficiency. Moreover, improper seating can cause damage to both the ball and the seat, which are the shortest wear items in the oil pump. When these are sufficiently worn, pumping operations must be interrupted and the entire oil pump removed for their replacement. Relatedly, while the seat can be inverted to extend its life, the constant rotation of the ball results in substantially even wear over the entire surface of the ball, making inversion to extend ball life impossible.  
           [0013]    Still another problem is related to the impurities commonly found in the oil, such as sand. Sand can become trapped between the side of the travelling valve and the interior wall of the oil pump. When it becomes trapped in this manner, the constant up and down motion of the travelling valve can lead to scoring of the travelling valve, ultimately reducing its effectiveness and sometimes requiring its replacement. Sand can also get between the ball and seat, preventing proper seating—possibly leading to damage and inefficiency.  
           [0014]    Yet another problem is encountered during deviated or non-vertical pumping operations. It is often necessary to conduct pumping operations in an angled or even horizontal direction, where for one reason or another—e.g., where a building is located directly over the hole—it is impossible to access the hole from directly above. In this instances, a well is sunk vertically at a distance from the site, and the well (including the oil pump) is then extended at an angle or perhaps even horizontally to the hole. Where the oil pump is operating in a non-vertical orientation, the travelling valve ball will be pulled by gravitational forces toward the side of the travelling valve, preventing it from fully seating potentially causing damage and inefficiency.  
           [0015]    The pumping of heavy crude also presents problems. The viscosity of this fluid can prevent the travelling valve ball from seating as quickly as it should for optimal performance. This reduces pumping efficiency.  
           [0016]    The present invention addresses these problems encountered in prior art pumping systems and provides other, related, advantages.  
         SUMMARY OF THE INVENTION  
         [0017]    It is an object of the present invention to provide an improved travelling valve that will more efficiently vent entrained gases, reducing instances of gas lock.  
           [0018]    It is a further object of the present invention to provide an improved travelling valve with increased wear resistance for its seat and ball components.  
           [0019]    It is a still further object of the present invention to provide an improved travelling valve which more efficiently centers the ball during seating.  
           [0020]    It is yet a further object of the present invention to provide an improved travelling valve where the ball will experience wear from seating on only one hemisphere, permitting inversion of the ball to extend its life.  
           [0021]    It is a further object of the present invention to provide an improved travelling valve that will more efficiently pass impurities through and around the valve, reducing damage to the outside of the valve, ball and seat.  
           [0022]    It is a still further object of the present invention to provide an improved travelling valve that will allow the ball to properly center on the seat during deviated or non-vertical pumping operations.  
           [0023]    It is yet a further object of the present invention to provide an improved travelling valve that will efficiently seat and unseat the ball during the pumping of highly viscous fluids such as heavy crude.  
         BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS  
         [0024]    In accordance with one embodiment of the present invention, an improved travelling valve for use in a pumping apparatus is disclosed. The improved travelling valve comprises, in combination: a ball having a passage therethrough; a seal stem adapted to couple to the ball through the passage; an anchoring assembly adapted to anchor the ball to the seal stem; a seat positioned on the seal stem below the ball; and a drag plunger coupled at a first end thereof to the seal stem.  
           [0025]    In accordance with another embodiment of the present invention, an improved travelling valve for use in a pumping apparatus is disclosed. The improved travelling valve comprises, in combination: a ball; a seat positioned below the ball; and means for imparting rotational movement to at least a portion of the improved travelling valve during pumping of fluid.  
           [0026]    In accordance with another embodiment of the present invention, a method for pumping fluid is disclosed. The method comprises, in combination: providing a ball having a passage therethrough; providing a seal stem adapted to couple to the ball through the passage; providing an anchoring assembly adapted to anchor the ball to the seal stem; anchoring the ball to the seal stem with the anchoring assembly; positioning a seat on the seal stem below the ball; coupling a drag plunger at a first end thereof to the seal stem; and pumping fluid through the travelling valve.  
           [0027]    The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiments of the invention, as illustrated in the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    [0028]FIG. 1 is a perspective, exploded view of an embodiment of the travelling valve of the present invention.  
         [0029]    [0029]FIG. 2 is a side, cross-sectional view of the travelling valve of the present invention.  
         [0030]    [0030]FIG. 3 is a top, cross-sectional view of the ported seal stem portion of the improved travelling valve shown in FIGS. 1 and 2, taken along line  3 - 3  of FIG. 2.  
         [0031]    [0031]FIG. 4 is a top, cross-sectional view of the ported seal stem portion of the improved travelling valve shown in FIGS.  1  and  2 , taken along line  4 - 4  of FIG. 2.  
         [0032]    [0032]FIG. 5 is a top, cross-sectional view of the vein rotator portion of the improved travelling valve shown in FIGS. 1 and 2, taken along line  5 - 5  of FIG. 2.  
         [0033]    [0033]FIG. 6 is a side, cross-sectional view of the ported seal stem, ball and anchor bolt portions of the improved travelling valve shown in FIGS. 1 and 2.  
         [0034]    [0034]FIG. 7 is a partially cut-away, perspective view of the improved travelling valve shown in FIGS. 1 and 2, illustrating the pathway taken by the pumped fluid and illustrating the rotation of portions of the travelling valve during pumping. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0035]    Referring first to FIGS.  1 - 2 , an embodiment of the travelling valve  10  of the present invention is shown. The main components of the travelling valve  10  are: (a) a cage  12 ; (b) an anchor assembly  14 ; (c) a ball  16 ; (d) a seat  18 ; (e) a seat plug  20 ; (f) a ported seal stem  22 ; (g) a mini-drag plunger  24 ; and a (h) a vein rotator  26 . The component parts of the travelling valve  10 , their function and construction can be illuminated through a description of the operation of the travelling valve  10 , in an oil pumping system. (Although the term “oil” is used herein, it should be understood that the travelling valve  10  of the present invention may be used to pump fluids other than oil, including for example debris-containing water.)  
         [0036]    During the downstroke, as with a typical prior art travelling valve, the ball  16  will be in an up or open position. On the upstroke, the ball  16  moves to a down or closed position. However, the manner in which the ball  16  of the travelling valve  10  moves from an open to closed position is different from that in prior art valves.  
         [0037]    First, attention is drawn to the passage  28  through the ball  16 , as shown most clearly in FIG. 6. The passage  28  allows the ball  16  to be slidably retained within a shaft  30 , which shaft  30  forms part of the anchoring assembly  14 . Still referring to FIG. 6, the anchoring assembly  14  includes two threaded sections  32 , which are received in a mating threaded area in the interior of the ported seal stem  22 . To guard against accidental dislodging of the threaded sections  32  from the ported seal stem  22 , set screws  34  (preferably allen-type screws) are installed through the ported seal stem  22  at an angle that is perpendicular to the threaded sections  32 . The set screws  34  should be positioned so that, when fully inserted, the ends thereof will contact a smooth section  36  of the anchoring assembly  14  located between the two threaded sections  32 . The proper positioning of the set screws  34  will prevent the lower threaded section  32  (the one most distal from the ball  16 ) from being removed from the interior of ported seal stem  22 .  
         [0038]    Moreover, to guard against loosening of the set screws  34  during operation of the oil pump, the set screws  34  are preferably positioned so as to be concealed by the seat  18 —with the seat  18  preventing the set screws  34  from exiting the ported seal stem  22 . When it becomes necessary to remove the set screws  34 , the seat  18  may be manually slid upward so as to expose the heads of the set screws  34 . The anchoring assembly  14  further includes a cap  38 , which is threadably retained thereto, and which secures the ball  16  at a top portion thereof.  
         [0039]    Addressing now the ported seal stem  22 , which can be seen in detail in FIGS. 1 and 6, it is generally cylindrical in shape, and has three regions of descending diameter sizes. These begin with a base  22   a , a smaller diameter middle portion  22   b , and a still smaller diameter top portion  22   c.  The base  22   a  has a plurality, and preferably four, channels  40  cut therein. At the base of each channel  40  is an opening  42  into the interior of the base  22   a . The channels  40  are angled. Where the travelling valve  10  is used in the northern hemisphere, the channels  40  should be cut—looking from the south or downhole end of the base  22   a , in a west to east direction. For use in the southern hemisphere, the channels should be cut in an east to west direction.  
         [0040]    The middle portion  22   b  has a plurality, and preferably four, channels  44  cut therein. The channels  44  are preferably continuous with the channels  40 , so that they maintain the same angled orientation and are continuous at their bases.  
         [0041]    Positioned over the middle portion  22   b  are the seat  18  and the seat plug  20 . The seat plug  20  is threaded on an upper portion thereof, and is dimensioned to be retained within a corresponding threaded portion in the interior of the cage  12 .  
         [0042]    The base  22   a  is threaded on an interior portion of the southern end thereof, and is dimensioned to receive a corresponding threaded male portion on the northern end of the mini-drag plunger  24 . The mini-drag plunger  24  is itself threaded on an interior portion of its southern end, and is dimensioned to receive a corresponding threaded male portion on the northern end of the vein rotator  26 . Formed in the southern end of the vein rotator are a plurality of angled channels  46 , which are angled in the same direction as channels  40  and  44 .  
       Statement of Operation  
       [0043]    The travelling valve  10  is coupled, directly or indirectly to a sucker rod, so that the travelling valve will move up with the upstroke of the pumping unit, and down with the downstroke of the pumping unit. The travelling valve is coupled at its north end by threadably coupling the north end of the cage  12  to the sucker rod or intermediate component between the cage  12  and the sucker rod.  
         [0044]    As with a prior art system, oil will be pumped from a hole through a series of “downstrokes” and “upstrokes” of the oil pump, which motion is imparted by the above-ground pumping unit. During the upstroke, formation pressure causes the ball in the standing valve to move upward, allowing the oil to pass through the standing valve and into the barrel of the oil pump. This oil will be held in place between the standing valve and the travelling valve  10 .  
         [0045]    In the travelling valve  10 , the ball  16  is located in the seated position on the seat  18 . It is held there by the mini-drag plunger  24 , which pulls the ball  16  into a positive closed position. The oil located above the travelling valve  10  is moved northward in the direction of the 3-wing cage at the end of the oil pump.  
         [0046]    On the downstroke, the mini-drag plunger  24  lifts the ball  16  in the travelling valve  10  off of the seat  18 , to a positive open position, permitting the oil that has passed through the standing valve to pass therethrough. Also during the downstroke, the ball in the standing valve seats, preventing the pumped oil from moving back down into the hole.  
         [0047]    With respect to the seating and unseating of the ball  16  relative to the seat  18 , it is not merely the ball  16  that is in motion. Instead, during the downstroke, each of the vein rotator  26 , mini-drag plunger  24 , ported seal stem  22 , and ball  16  secured by anchor assembly  14  will move up and down during operation of the oil pump. The seat  18  is held in stable position relative to the cage  12  (and thus the sucker rod) with the seat plug  20 , which is threadably coupled to the cage  12 .  
         [0048]    Because the ball  16  is fixed to ported seal stem  22 , it can be seen that only the lower hemisphere of the ball  16  will contact the seat  18  during operation of the oil pump—the ball  16  will not invert during operation. As a result, only the lower hemisphere will experience the wear associated with such seating and unseating. When that portion is sufficiently worn, the ball  16  may be removed from the ported seal stem  16  by removal of the set screws  34  and cap  38  and inverted—so that the unworn upper hemisphere is now exposed to the seat  18 .  
         [0049]    Moreover, because the ball  16  is fixed to the ported seal stem  22 , the movement of the ball  16  to an open and closed position is controlled, with the result that the ball  16  will accurately center on the seat  18  each time. This accurate centering will reduce damage to the ball  16  and seat  18 . It is also of particular value in deviated or non-vertical drilling operations, as a guard against the gravitational forces that would tend to cause a free floating travelling valve ball to seat in an off-center position. Relatedly, because the ball  16  moves relatively quickly from a positive open to a positive closed position—instead of being permitted to float in an intermediate position that is between open and closed and instead of being able to slowly move between such positions—the travelling valve  10  of the present invention can more efficiently pump highly viscous fluids such as heavy crude.  
         [0050]    Referring now to FIG. 7, as the oil moves through the travelling valve during the downstroke, the passage of the oil through the channels  46  at the base of the vein rotator  26  contributes to a rotation of the vein rotator  26 , mini-drag plunger  24 , ported seal stem  22 , and ball  16  secured by anchor assembly  14 . The oil then passes through the interior of the mini-drag plunger  24 , exiting openings  42 , and passing through channels  40  and  44 . The passage of the oil through channels  40  and  44  further imparts rotation to the vein rotator  26 , mini-drag plunger  24 , ported seal stem  22 , and ball  16  secured by anchor assembly  14 . The oil then passes through the interior of the seat plug  20  and seat  18 , around the ball  16 , and into the cage  12 —before passing northward through the oil pump and toward the flow line. The arrows in FIG. 7 around the travelling valve  10  illustrate the direction of rotation of the vein rotator  26 , the mini-drag plunger  24 , the ported seal stem  22 , and the ball  16  secured by anchor assembly  14 . The arrows in FIG. 7 within the travelling valve  10  illustrates the path taken by the pumped fluid as it passes through the travelling valve  10 .  
         [0051]    The rotation of portions of the travelling valve  10  as described above causes spiraling of the oil as it passes through the travelling valve  10 . This spiraling has several beneficial effects. First, the spiraling of the fluid creates centrifugal forces that contributes to the elimination of entrained gasses from the pumped fluid, making it easier for these gasses to bubble to the surface—thereby reducing the incidence of gasses building up in sufficient quantity within the oil pump to create gas lock.  
         [0052]    Spiraling of the fluid also causes solid impurities, such as sand, to move to the middle of the fluid, leaving the outside portions of the fluid cleaner. In such position, the solid impurities are less likely to cause harm to the seat  18  or ball  16  as the fluid passes through. Relatedly, spiraling of the fluid reduces the likelihood that impurities will become trapped between the side of the travelling valve  10  and the interior wall of the oil pump—tending to cause dislodging of such impurities and their passage to the surface with the pumped fluid.  
         [0053]    While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.  
         [0054]    For example, it would be possible to combine certain of the component portions of the travelling valve  10 , so as to reduce the number of individual parts. Thus, the vein rotator  26  and mini-drag plunger  24  could be a one-piece assembly. Moreover, while rotational movement of a portion of the travelling valve and a spiraling of the pumped fluid is achieved by the combination of channels  40 ,  44  and  46 , it would be possible to impart some beneficial rotational movement with fewer groups of channels—e.g., only channels  46 , or only channels  40  and  44 , or only channels  40  and  46 , etc. Still further, it would be possible to provide fewer or greater numbers of individual channels  40 ,  44  and  46 .