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BACKGROUND OF THE INVENTION 
   This invention relates to an inline valve. More particularly, but not by way of limitation, this invention relates to a flow valve used in the drilling of wells, and a method of using the flow valve. 
   In the search for oil and gas, operators drill wells many thousands of feet into the earth. The target of the drilling programs are subterranean reservoirs that contain hydrocarbons in liquid and gaseous states. A rotary drill bit is used to bore the hole. Different types of drilling bottom hole assemblies are available. For instance, a traditional tri-cone bit may be attached to a drill string, and wherein the drill string is rotated from the surface in order to rotate the bit. Another bottom hole assembly includes a drill motor placed upstream of the bit, and wherein the drill string remains stationary, but the drill motor causes the bit to turn thereby boring the well. 
   Generally, a drilling fluid is circulated within the bore hole. The drilling fluid has several purposes including but not limited to lubricating the bit, preventing hole sloughing, and containing the in-situ reservoir pressure. In some instances, the reservoirs are over pressured. Ideally, an operator would utilize a heavier drilling fluid which has the effect of increasing the hydrostatic pressure of the drilling fluid column which in turn controls the reservoir pressure from migrating into the well bore. However, in some cases, the in-situ reservoir pressure migrates out into the well bore in an event known as a kick. These kicks can be very dangerous since they can lead to blow outs. As readily understood by those of ordinary skill in the art, the migration of reservoir fluids, and in particular natural gas, causes the hydrostatic drilling fluid column to decrease in pressure, which in turn can lead to the blowout. 
   Numerous devices have been used to prevent blowouts. All these devices suffer from certain deficiencies in today&#39;s drilling environment. There is a need for a valve that controls flow of a medium from an oil and gas well. There is a need for a flow valve that can be used in conjunction with a drill string, with the flow valve being placed close to the bit. There is also a need for a device that will prevent and/or control the migration of the pressure into the drill string&#39;s inner diameter. There is also a need for a device that will prevent premature breakage of the valve spring during usage. In another embodiment, there is a need for a flow valve that can control the flow at the surface of a drilling rig. These and many other needs will be met by the invention herein disclosed. 
   SUMMARY OF THE INVENTION 
   An apparatus for controlling the flow of a medium is disclosed. The apparatus comprises a base having a plurality of arms extending from the base and a seat housing abutting the plurality of arms. In the preferred embodiment, the base and arms define a cage, and wherein the seat housing includes a valve seat. A valve member is positioned within the cage. 
   The apparatus further comprises a biasing means for biasing the valve member into engagement with the valve seat, and a biasing housing disposed within the base, and wherein the biasing means is disposed within the biasing housing. 
   The apparatus further includes a passageway formed about the valve member when the flow of the medium is from the surface through the apparatus in a first direction, and wherein the flow medium flows on the outer portion of the biasing housing. The flow of the medium in a second direction urges the ball into engagement with the valve seat. When the flow of the medium is in the first direction, the biasing means is collapsed so that flow of the medium proceeds through the apparatus, and in this position, the valve member blocks the flow of the medium from entering the biasing housing. 
   In the preferred embodiment, the valve member is a ball member. Also, the biasing means may be a spring and the apparatus further comprises a ball stop seat formed on the spring housing. The apparatus may further include a bleed off vent passage positioned within the seat housing for communicating a pressure upstream of the ball with a pressure downstream of the ball. 
   The apparatus may be located within a work sting within a well bore, and the medium may be a drilling fluid. In this embodiment, the work string is connected to a bit for boring the well bore. The apparatus may also be located in the Kelly of a drilling rig. 
   A method for drilling a well bore is also disclosed. The method includes providing a work string within the well bore, the work string having a bit, as well as providing a valve device within the work string. The valve device comprises: a base having arms extending from the base, a seat housing abutting the arms; a valve member positioned within the base; a biasing member for biasing the valve member into engagement with a valve seat; a biasing housing disposed within the base, with the biasing means disposed within the biasing housing; wherein the flow of the medium in a first direction biases the biasing member so that flow of the medium proceeds through the valve device, and the flow of the medium in a second direction urges the valve member into engagement with the valve seat. The method further includes flowing the medium in the first direction through the work string and unseating the valve member from the valve seat so that a passageway is formed about the valve member when the flow of the medium is in the first direction. Next, the method includes directing the medium about the biasing housing and drilling the well bore with the bit. 
   The method may further include drilling through a subterranean reservoir containing hydrocarbons. A gas may migrates from the reservoir into the well bore, and the gas flows in the second direction. The valve member moves in the second direction with the biasing member and the valve member engages with the valve seat. The drilling can then be terminated. In the most preferred embodiment, the biasing means is a spring. 
   The method may further include pumping a weighted fluid into an internal portion of the work string, compressing the spring, and disengaging the valve member with the valve seat. A weighted fluid can be pumped through the bit and into the well bore which in turn controls the migration of the gas into the well bore. The method would then include resuming the drilling with the bit. 
   An advantage of the present invention includes use of a blow out preventor that is placed down hole near the bit. Another advantage is the invention can be used with traditional drill strings that are rotated from the rotary on the drill floor. Yet another advantage is that the invention can also be used with measurement while drilling electronic devices. Still yet another advantage is that the invention can be used with down hole mud motors that rotate the drill bit while the drill string remains static. 
   A feature of the invention is that coiled springs may be used as the biasing means. Another feature is that flow of the medium through the spring and the spring housing is prevented which in turn reduces cycling of the spring, which is sometimes referred to as chatter. Still yet another feature is that a flow path is created around the valve element. Yet another feature is that the flow path thus created allows a maximum flow area thereby reducing pressure drops through the valve during pumping. Another feature is that the flow valve can be used in conjunction with the Kelly on the rig for controlling pressure during drilling operations. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric view of the base of the present flow valve. 
       FIG. 2  is an isometric view of the base, seat housing, valve member and biasing member of the present flow valve. 
       FIG. 3  is a cross-sectional view of the flow valve of the present invention. 
       FIG. 4  is a partial cross-sectional view of the flow valve seen in  FIG. 3  situated within a drill string embodiment in a well bore, with the valve in the open position. 
       FIG. 5  is the partial cross-sectional view of the flow valve seen in  FIG. 4 , with the valve in the closed position. 
       FIG. 6  is a schematic of a second embodiment of the flow valve seen in  FIG. 3  operatively associated with a Kelly on a drilling rig. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to  FIG. 1 , an isometric view of the base  2  of the present down hole valve will now be described. Please note that the base  2  is also sometimes referred to as the pedestal  2 . The base  2  includes a first leg  4 , second leg  6 , and third leg  8  that extend from a cylindrical member  12 . The cylindrical member  12  is also referred to as the biasing housing  12 . The biasing housing  12  has a first end  14  and a second end  16 , and wherein the first end  14  is also referred to as ball stop  14  as will be more fully explained later in the application. The leg  4  is connected to the cylindrical member  12  with the connector portion  18 , the leg  6  is connected to the cylindrical member  12  with the connector portion  20 , the leg  8  is connected to the cylindrical member  12  with the connector portion  22 . 
     FIG. 2 , which is an isometric view of the base  2 , seat housing  26 , valve member  28  and biasing member  30  of the present down hole valve, will now be described. It should be noted that like numbers appearing in the various figures refer to like components. The seat housing  26  is generally a cylindrical member with an outer portion having external thread means  32 , with the external thread means  32  extending to the end  34 . The legs  4 ,  6 ,  8  are attached to the end  34  via conventional means such as welding, even though the legs could have been attached via nuts and bolts; also, the legs could have been formed integrally thereon. The legs  4 ,  6 ,  8  and seat housing  26  define a cage for placement of the valve member  28 . 
   Although not shown in  FIG. 2 , the seat housing  26  has a valve face that will engage with the valve member  28 . In the preferred embodiment, the valve member  28  is a spherical ball member  28 . The spherical face of the ball member  28  will engage and come into contact with the valve face of the valve member  28 . In one preferred embodiment, the valve face is configured to receive and sealingly engage the spherical ball member  28 . 
     FIG. 2  further depicts the biasing member  30 . More specifically in one preferred embodiment, the biasing member  30  is a coiled spring  30 . A spring guide  35   a  is disposed within the coiled spring  30 . The spring guide  35   a  has a first end that contains a cradle  35   b  that engages the ball member  28 . The cradle  35   b  is generally in a concave shape that engages the ball member  28 . The spring guide  35   a  has a second end  35   c  that is slidably disposed in opening  35   d.    
   Referring now to  FIG. 3 , a cross-sectional view of the flow valve  37  of the present invention will now be described. The spring guide  35   a  and spring  30  are partially disposed within the biasing housing  12 . Seal means, such as o-ring  35   e , may also be included. The coiled spring  30  has a first end  36  abutting the cradle  35   b  of the spring guide  35   a , as shown in  FIG. 2 . 
   As shown in  FIG. 3 , the spring guide  35   a  prevents the coiled spring  30  from buckling during use and generally keeps the coiled spring  30  aligned properly within the valve  37 , and in particular, within biasing housing  12 . A second end of the coiled spring  30  abuts the first end  14  of the biasing housing, and wherein the first end  14  is sometimes referred to as the ball stop  14  (the ball stop  14  is seen in  FIG. 1 ). The valve member  28  is normally closed due to the biasing member  30  urging the valve member  28  into engagement with the valve face. 
   The flow valve  37  includes the base  2 , the biasing housing  12 , the seat housing  26  and the valve member  28 , which are encased in an outer housing  38 . The outer housing  38  is generally cylindrical with an outer surface  40  that extends to the end sub  41   a . The outer housing  38  is threadedly connected to the end sub  41   a . End sub  41   a  has end  42  which in turn extends radially inward to the chamfered shoulder  44 . An end  46  of leg  8  and an end  48  of leg  4  abut the chamfered shoulder  44 . The end sub  41   a  has a pair of o-rings,  41   b ,  41   c , that will seal pressure when the flow valve  37  is disposed within an outer member, such as seen in  FIG. 4 . 
   Returning to  FIG. 3 , the outer housing  38  has an inner portion  50  and wherein inner portion  50  extends to the inner thread means  52 , and wherein inner thread means  52  will cooperate and engage with the external thread means  32  of the seat housing  26 . The outer housing also contains o-ring seals  53   a  for sealing with an outer member. Hence, in one preferred embodiment, once the base  2 , biasing housing  12 , seat housing  26 , and valve member  28  are placed within the outer housing  38  and the outer housing  38  is connected to the seat housing  26  and the end sub  41   a , the flow valve  37  can be placed into a work string, as will be more fully explained later in the application. 
   As shown in  FIG. 3 , the seat housing includes a valve face  54 . As noted earlier, the valve member  28  is biased into engagement with valve face  54  via spring  30 . Additionally, in the orientation shown in  FIG. 3 , the flow valve  37  is in the position associated with an influx of gas into the work string i.e. a kick. The flow arrow  56   a  depicts the upward flow on one side of the biasing housing  12 , the flow arrow  56   b  depicts the upward flow on the other side of the biasing housing  12 , and the flow arrow  56   c  depicts the upward flow acting against the end  35   c . It should be noted that seal means, such as o-ring  35   d , can be included. 
   The valve face  54  is configured to receive and engage with the ball member&#39;s  28  spherical contour. The flow valve  37 , in the preferred embodiment, is configured to be a normally closed valve. In other words, the spring  30  normally biases the ball  28  into engagement with the valve face  54  when there is no flow down the work string. If the operator begins pumping a medium, such as a drilling fluid, down the work string, the pumping will cause the spring  30  to compress thereby opening the passageway. However, in the case where a kick is experienced, such as seen in  FIG. 3 , the flow from the subterranean reservoir (represented by flow arrows  56   a ,  56   b ,  56   c ) and the spring  30  will close the down hole valve  37 . 
   Also included with the flow valve  37  is the bleed off vents  58   a ,  58   b . The bleed off vents  58   a ,  58   b  allow pressure that may have built up below the valve member  28  to equalize with the area above the valve member  28 . Hence, in the case of a kick, the valve  37  will be in the closed position seen in  FIG. 3 , and with the bleed off vents  58   a ,  58   b , the pressure can be bleed off to the area above the ball  28 , with the area being denoted by the letter “A”. It should be noted that in cases where an operator does not wish to bleed off vents  58   a ,  58   b , a set screw (not shown) can be threadedly made up with the bleed off vent  58  so that the vent is closed and pressure can not pass through the vent to the area “A”. 
   Referring now to  FIG. 4 , a partial cross-sectional view of the flow valve  37  seen in  FIG. 3  is situated within a bottom hole assembly attached to a drill string (drill string not seen in this view). The drill string is positioned within a well bore  72 , with the valve  37  in the open position which corresponds to the operator pumping a drilling fluid down the inner portion of the drill string. In this embodiment, the drill string is attached to a bottom hole assembly that includes a measurement while drilling tool (MWD tool)  74  which can measure and calculate certain electrical and nuclear properties of the drilled subterranean formation such as resistivity and gamma ray values, as is readily understood by those of ordinary skill in the art. 
   A bit sub  76  is threadedly made up to the MWD tool  74 . The bit sub  76  has a radial shoulder  78  formed on the inner portion thereof, and wherein the down hole valve  37  is configured to abut the radial shoulder. Additionally, the MWD tool  74  has its end  80  cooperate with the upper portion of the seat housing  26  so that the valve  37  is secured in place within the bottom hole assembly seen in  FIG. 4 . The bit sub  76  is connected to the bit  82  In  FIG. 4 , the bottom hole assembly consist of the bit  82 , bit sub  76  and MWD tool  74 . 
   In operation, a medium is pumped down the inner portion of the drill string. The medium in the preferred embodiment is a drilling fluid, although the medium could be air, salt water, etc. As noted earlier, the drilling of the well bore  72  is caused by the rotation of the bit. As the medium travels through the inlet port  81  and area A of the seat housing  26 , this will cause the spring  30  to collapse (i.e. compress), as mentioned earlier. Note that a passageway is formed about the valve member  28 , with the flow arrows  82   a ,  82   b  representing the medium through the passageway and legs of the base  2 . The medium exits the bit  82  and the medium then travels up the annulus area  84 . 
     FIG. 5  is a partial cross-sectional view of the flow valve  37  seen in  FIG. 4 , with the valve  37  having been moved to the closed position. The position seen in  FIG. 5  corresponds to the situation wherein the well bore  72  has experienced a kick or if there is no flow, and therefore, valve  37  is in its normally closed position. As noted earlier, the flow allows the spring  30  to extend the ball  28  into engagement with the valve face  54 , with the arrows  56   a ,  56   b ,  56   c  representing the flow path of the medium urging the ball  28  to the closed position. The internal portion of the drill string is closed and therefore the increase of pressure within the drill string will be controlled. In the case where the vents  58   a ,  58   b  have been included, the vents  58   a ,  58   b  will allow a controlled equalization of pressure into the internal portion of the drill string in area “A” and internal portion of the drill string. 
     FIG. 6  is a schematic of a second embodiment of the flow valve  37  seen in  FIG. 3 . In this embodiment, the flow valve  37  is situated in line with a Kelly  90 .  FIG. 6  depicts a drilling rig  92  with a block  94  that is operatively associated with the drawworks, as understood by those of ordinary skill in the art. A swivel  96  is suspended from elevators  98 , and wherein the Kelly  90  is attached to the swivel  96 . The Kelly  90  will be attached to the rotary bushing  98 , and wherein a rotary table will rotate the bushing  98  and Kelly  90 . The flow valve  37  is seen connected in-line with the Kelly  90 . A work string, such as a drilling string  100 , extends into a well bore  102 . The drill string  100  may have the bit  82  and MWD  74  operatively attached. 
   Flow down the work string  100  is possible, and if the well bore  102  experiences a kick, the flow valve  37  will be urged closed in the manner previously described, thereby containing the high pressure liquids and gas within the Kelly. In order to kill the well, a weighted kill fluid can be pumped through the flow valve  37  into the well bore  102 . In this manner, the flow valve operates as a one-way check valve. Thus, according to the teachings of present invention, the flow valve  37  can be operated at the surface as well as down hole in conjunction with a bottom hole assembly. 
   Changes and modifications in the specifically described embodiments can be carried out without departing from the scope of the invention which is intended to be limited only by the scope of the appended claims and any equivalents thereof.

Summary:
An apparatus for controlling the flow of a medium. The apparatus comprises a base having a plurality of arms extending from the base. The base and arms define a cage. A valve member is positioned within the cage. The apparatus further includes a biasing housing disposed within the base, and wherein a spring is disposed within the biasing housing. The apparatus further includes a passageway formed about the valve member when the valve member is opened so that the medium flows on the outer portion of the biasing housing, and wherein the flow of the medium in an opposite direction urges the ball into engagement with the valve seat. When the valve is open, the medium collapses the spring and the valve member blocks the flow of the medium from entering the biasing housing. A method of drilling a well with the flow valve positioned on a work string is also disclosed.