CA2491931A1 - Drill pipe float valve - Google Patents
Drill pipe float valve Download PDFInfo
- Publication number
- CA2491931A1 CA2491931A1 CA 2491931 CA2491931A CA2491931A1 CA 2491931 A1 CA2491931 A1 CA 2491931A1 CA 2491931 CA2491931 CA 2491931 CA 2491931 A CA2491931 A CA 2491931A CA 2491931 A1 CA2491931 A1 CA 2491931A1
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- Canada
- Prior art keywords
- valve
- body portion
- cylindrical
- orifice
- seal element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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- 239000012530 fluid Substances 0.000 claims abstract description 18
- 230000013011 mating Effects 0.000 abstract 1
- 238000007789 sealing Methods 0.000 description 7
- 238000005553 drilling Methods 0.000 description 3
- 239000013536 elastomeric material Substances 0.000 description 3
- 230000003628 erosive effect Effects 0.000 description 2
- 239000003082 abrasive agent Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/10—Valve arrangements in drilling-fluid circulation systems
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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Self-Closing Valves And Venting Or Aerating Valves (AREA)
Abstract
A drill pipe float valve for location in a drill string to allow flow down the drill string but providing a sealed closure against flow upwardly when the downhole pressure exceeds the pressure above the valve. The valve includes a body formed by upper and lower body portions which are threaded together and are separable in a manner to permit easy removal and replacement of an orifice seal element. On re-assembly of the two body portions, the seal element is secured between mating parts in a manner to readily secure the seal element in its operative position and to protect a major portion of the seal element from contact with the flow of fluid through the valve.
Description
DRILL PIPE FLOAT VALVE
Field of The Invention The invention relates to a valve structure and more particularly to a float valve for use in a string of drill pipe to control the flow of fluid therethrough during drilling of wells.
Background of The Invention Float control valves are utilized in drill pipes for controlling the flow of fluid therethrough, so that fluid, such as drilling mud, is permitted to flow downwardly through the string but fluid under pressure is prevented from returning under pressure upwardly through the drill connected series of drill pipes, such as in the event of a blow-out. Various forms of such float control valves have been devised to provide characteristics of substantially, unrestricted flow downwardly through the valve and quick closure of the valve when circulation of the pressurized flow from above is stopped or a sudden rise in pressure is experienced downhole. An example of this type of valve is in the form of a flapper valve shown in U.S. Patent No. 3,058,534, J.D. Keithhahn, October 16, 1962. Such a valve has been used in the drilling industry for many decades.
Drill pipe float valves are exposed to extreme operating conditions such as the passage of abrasive materials under relatively high pressure, and thus erosive wear of certain parts cannot be entirely avoided. The above identified U.S. Patent describes a structure in which provision is made for protection of a resilient sealing element which is located to allow a press fit of a valve head with a valve seat in the closed position.
While such an arrangement has proven effective, the seal element is subject to deterioration over extended periods of time and erosion occurs at the exposed lower edge of the sealing element, which is the portion of the sealing element providing the sealing of the valve head when in its closed position. Accordingly, replacement of the seal element is necessary from time to time to ensure an effective valve closure. In the known structure the seal element is maintained in its seat and protected by a metallic sleeve which is installed with a press fit.
When it becomes apparent that the seal must be replaced, it is difficult, if not impossible, to remove the sleeve to allow removal of the damaged seal element and replacement of the seal element with the usual tools available on site.
Summary of the Invention It is an object of the present invention to provide a drill pipe float valve having a structure providing the maximum protection of the seal element while permitting ready changing of a seal element of the valve with the use of commonly available tools on site.
According to the present invention there is provided a drill pipe float valve including upper and a lower body portions having a threading connection therebetween for end-to-end connection so as to form a unitary cylindrical valve housing in a final threaded relationship for reception in an internal cavity in a string of connected drill pipe members. The body portions define together a continuous fluid passageway throughout the length of the unitary valve housing with one of the body portions defining an orifice area in the passageway. A
valve closure member is mounted in one of the body portions and defines a face for movement to a closed position in relation to the orifice area. An elastomeric seal element has a cylindrical portion positioned within the orifice with one end thereof defining an annular face for engagement by the face of the valve closure member in the closed position.
The seal element also has an annular flange extending externally from the cylindrical portion. One body portion of the valve defines an annular shoulder adjacent the orifice, and the other body portion defines a second annular shoulder. The shoulders are located to move into close facing proximity to each other as the body portions are threaded to the final threaded relationship so as to clamp therebetween the annular flange of the seal element.
More specifically, the invention relates to a float valve for inclusion in a drill pipe, and wherein the float valve includes a valve body having an outer surface for close reception in a counterbore of the drill pipe string. The float valve has an upper body portion and a lower body portion, the body portions having outer, aligned cylindrical surfaces of common diameter and aligned central passages therethrough for allowing fluid flow through the valve body. The lower body portion has an enlarged cylindrical, internally threaded opening in an upper end therein and terminating at a valve orifice at a lower end of the threaded opening, the valve orifice being defined by a short cylindrical section of less diameter than the internally threaded opening and being located between an upper circular shoulder portion above the valve orifice and a lower valve seat area therebelow. A valve closure member is contained in the central passage of the lower body portion below the valve orifice and provides a valve surface movable to a closed position immediately below the valve seat area. The upper body portion has a lower projection including an externally threaded section for reception in the threaded opening of the lower body portion so as to provide a connection of the upper and lower body portions and thus provide a unitary body when connected. The lower projection terminates in an extended cylindrical section which is below its externally threaded section and is of less diameter than both the externally threaded portion and the valve orifice. The lower projection of the upper portion is separated from the externally threaded portion thereof by an annular surface providing a lower shoulder of the upper body portion. An elastomeric seal element is formed by a cylindrical body having an upper lateral flange and a lower end defining a lower seal edge for engagement by the upper surface of the valve member. The cylindrical body of the seal element has an outer cylindrical surface for close reception within the valve orifice and an inner cylindrical surface for close reception of the extended cylindrical section of the upper body portion. T'he lateral flange of the seal element extends radially outward therefrom and defines upper and lower surfaces for engagement between the lower shoulder of the projection of the upper body portion and the upper circular shoulder of the orifice in the lower body portion. The cylindrical body of the seal element extending between the lower surface of the flange and the lower seal edge is of a length slightly greater than the short cylindrical section defining the valve orifice so that the lower seal edge is spaced a short distance between the lower edge of the valve orifice.
In a preferred form of the invention, the extended cylindrical section of the upper body portion has a length slightly less than the length of the total cylindrical portion of the seal element so that the lower seal edge of the seal element is spaced a short distance below the extended cylindrical section of the upper body member. In this arrangement, the externally cylindrical section of the upper body portion shields the seal element from the flow of fluid passing downwardly through the orifice.
Brief Description of Drawings Figure 1 is a cross sectional view of the drill pipe float valve of the present invention as located within a drill pipe;
Figure 2 is a cross sectional view of a prior art drill pipe float valve;
Figure 3 is an enlarged cross sectional view showing in greater detail the relationship of the essential elements of the present invention;
Figure 4 is yet a further enlargement of a portion of the valve in the area of the seal element as indicated in the circle A of Figure 3; and Figure 5 is a perspective view of the upper and lower body portions of the present invention in a separated condition.
Detailed Description of the Invention In Figure 1, the drill pipe float valve of the present invention, which is denoted generally by the reference number 10, is shown installed in a drill string or pipe 11 at a threaded connection 14 between an upper drill pipe member 12 and a lower drill pipe member 13. The drill string defines a continuous passage 18 therethrough for the flow of pressurized fluid to the lower end of the string. In the shown arrangement the lower drill pipe string member 13 is a drill collar and it provides an internally threaded female portion of the connection 14, commonly referred to as a box. It is to be appreciated that while reference is made herein to a drill pipe float valve, the float valve of the present invention is designed for being installed in different locations in a drill string, such as between two adjacent drill pipes, or as illustrated herein, within a drill collar which is at the lower end of the drill pipe string and is usually connected directly to the drill bit. A
counterbore 16 extends downwardly from the box or threaded portion 14 to a lower shoulder 17.
The float valve 10 has an outer diameter to be closely received within the counterbore 16 which has a length selected to permit the lower end of the float valve 10 to be spaced slightly from shoulder 17 of the lower drill pipe member 13 in order that the valve may float freely in the counterbore 16 between a lower end 15 of the upper drill pipe member 12 and the shoulder 17 when the male threaded portion or pin of the upper pipe member 12 is tightly threaded into the upper end of the lower drill pipe member I 3.
The float valve 10 is formed with a valve cage or body 20 which provides an outer cylindrical surface 23 machined for fitting closely within the counterbore 16.
The valve body 20 consists of upper body portion 21 and a lower body portion 22 which when assembled provide the unitary float valve of constant outer diameter. Adjacent the lower end of the outer surface of lower body portion 22 there is a peripheral groove 31 into which is fitted a flange of a bottom cushion member 32 of elastomeric material provided to engage the shoulder 17 of the counterbore 16. Near the top of the upper body portion 21 there is formed in the outer cylindrical surface of the valve body 20 a pair of spaced grooves 29,29, I S which are shaped to receive a pair of seal rings 30,30 of elastomeric material. The seal rings are orientated in opposite sealing directions so as together resist passage of fluid between the outer cylindrical surface 23 of the valve body 20 and the wall of the drill pipe member defining the counterbore 16.
As indicated, the upper body portion 21 and the lower body portion 22 are formed with common outer diameters so that together they have aligned outer cylindrical surfaces.
The upper and lower bodies also define concentrically disposed central passages 25 and 26 to provide the assembled valve 10 with a continuous fluid passageway therethrough. This passageway aligns with the passage 18 of the drill pipe 11, and as further described below, permits the flow of fluid downwardly through the drill pipe 11 when the pressure of the fluid above the valve is greater than downhole pressure in the well being drilled.
Referring briefly to the features of a commonly used float valve illustrated in Figure 2, it may be noted that this prior structure is provided with a flap valve fv which, when closed, provides an upper face for engagement with a lower annular face of a rubber-like seal element se. The seal element se is maintained in an orifice of the valve by a retainer sleeve rs which is installed within the valve body with a press fit. When the seal element se deteriorates or otherwise becomes worn or damaged in use so as to require replacement, it can only be removed by first driving the retainer sleeve rs from its seat.
Such an operation and the reseating of the retaining sleeve are extremely difficult to achieve particularly with tools normally available on site.
With particular reference to Figure 3, it may be noted that in the structure of the float valve 10 of the present invention, the assembled valve body 20 is formed of separate upper body portion 21 and lower body portion 22 connected by a threaded connection 24. The lower body portion 22 provides an enlarged internally threaded opening 40 extending downwardly from an upper end 38 of the lower body portion 22. In the illustrated embodiment, the lower body portion 22 has spaced below the threaded opening 40 thereof a portion defining a valve orifice area 41 which is of lesser diameter than the threaded opening. As shown, the valve orifice area 41 is provided by a short cylindrical wall section 42 located between an upper annular shoulder portion 43 above the orifice area 41 and a lower valve seat area 44 below the valve orifice.
Below the lower valve seat area 44, the lower body portion 22 forms an internal cylindrical cavity which provides the central passage 26. Mounted in this internal cylindrical cavity is a valve closure member 33 which is shown as being a flapper valve in the form of a flapper plate 34 having an upper surface providing a valve seal surface 37.
The flapper plate 34 is pivotally mounted within the internal cylindrical cavity of the lower body portion 22 by way of a pivot pin 35. A spring 36 normally urges the flapper plate to the orifice closure position as shown in Figures l and 3 in which the upper surface or valve seat surface 37 of the flapper plate 34 is in proximity to the valve seat area 44. The pressure exerted by the spring 36 to close the valve is not great but is calibrated to swing the valve to the closed position when the pressure in the fluid above the valve 10 is not greater than the fluid pressure below the valve 10. Increase in the pressure of the fluid downhole forces the plate into a more effective sealing relationship.
The upper body portion 21 includes a lower projection 50 providing an externally threaded section 51 for threading engagement within the internally threaded opening 40 of the lower body portion 22, the projection SO extending downwardly from a lower shoulder 49. Below the externally threaded section 51, the lower projection includes an extended cylindrical section 52 of less diameter than valve orifice 41 and terminating in a lower end in the form of an annular bottom surface 53 of the upper body portion 21. The extended cylindrical section 52 is of less diameter than the externally threaded section of the upper body portion and is separated therefrom by an annular lower shoulder 55.
A seal element 56 which is formed of elastomeric material has a cylindrical body 57 having an inner cylindrical surface 60 for close engagement with the external surface of the extended cylindrical section 52 at the lower end of the upper body portion 21, as best seen in Figures 4. At the upper end of the cylindrical body 57, there is provided an outwardly projecting, upper lateral flange 58, the upper surface 59 of which is coplanar with the top of the cylindrical body 57. A lower surface 62 of the lateral flange 58 is spaced from a lower seal edge 63 of the cylindrical body a distance slightly greater than the short cylindrical wall section 42 forming the valve orifice. The total inner length of the cylindrical body 57 is slightly greater than the length of the lower projection 50 which extends from the lower shoulder 55 to the annular bottom surface 53 of the lower projection of the upper body portion 21. Accordingly, a very short portion of the very lower part of the cylindrical body 57 of the seal element 56 projects below the valve seal area 44 of the orifice and also below the annular bottom surface 53 of the lower projection 50 of the upper body portion 21.
It may be observed that the thickness of the lateral flange 58 of the seal element is such in relation to the relative positions of the lower shoulder 55 of the upper body portion 21 and the upper annular shoulder 43 of the lower body portion 22 that as upper end 38 of the lower body portion 22 engages the lower shoulder 49 of the upper body portion 21, the shoulders 5_S and 43 of the upper body portion and the lower body portion, respectively, tightly engage the upper surface 59 and lower surface 62 of the lateral flange 58. The seal element is thus received in its final position with its lower seal edge 63 exposed slightly below the annular bottom surface 53 of the upper body portion 21 and the lower valve seat area 44 in the lower body portion 22. Thus, the lower seal edge 63 is positioned to be contacted by the upper valve seat surface 37 of the flapper plate in a sealing relationship.
With the illustrated relationship between the seal element 56 and the orifice defined by the valve orifice area 41 in the lower body portion 22 and the positioning of the extended cylindrical section 52 of the upper body portion 21 within the orifice area, the seal element 56 is protected from the flow issuing from the central passage 25 of the upper body portion 21 into the central passage 26 of the lower body portion.
The very upper end of the upper body portion 21 is provided with a pair of opposed flats 27,27 one of which is apparent in Figure 4, in order that the upper body portion 21 may be gripped between the jaws of a wrench so that on holding the lower portion, such as in the jaws of a vice, the two body portions can be separated. Accordingly, when it becomes apparent that the valve is not fully effective due to a damaged seal element, or if it is deemed advisable to change the seal element 56 at a time when the float valve is readily accessible, the upper body portion 21 can be quickly removed from the lower body portion and the old seal element 56 can be removed by hand. A new seal element need then only be slid over the extending cylindrical section 52 of the upper body portion 21 before it is rethreaded back into the internally threaded opening 40 of the lower body portion 22. As the threading is earned out the seal element 56 enters the valve orifice area 41 and proceeds to its final position as the lateral flange becomes clamped between the shoulders 43 and 55 on final tightening of the two body portions 21 and 22.
It will be apparent to those skilled in the art that various modifications to the preferred embodiment disclosed above without departing from the spirit of the invention as set forth in the appending claims.
Field of The Invention The invention relates to a valve structure and more particularly to a float valve for use in a string of drill pipe to control the flow of fluid therethrough during drilling of wells.
Background of The Invention Float control valves are utilized in drill pipes for controlling the flow of fluid therethrough, so that fluid, such as drilling mud, is permitted to flow downwardly through the string but fluid under pressure is prevented from returning under pressure upwardly through the drill connected series of drill pipes, such as in the event of a blow-out. Various forms of such float control valves have been devised to provide characteristics of substantially, unrestricted flow downwardly through the valve and quick closure of the valve when circulation of the pressurized flow from above is stopped or a sudden rise in pressure is experienced downhole. An example of this type of valve is in the form of a flapper valve shown in U.S. Patent No. 3,058,534, J.D. Keithhahn, October 16, 1962. Such a valve has been used in the drilling industry for many decades.
Drill pipe float valves are exposed to extreme operating conditions such as the passage of abrasive materials under relatively high pressure, and thus erosive wear of certain parts cannot be entirely avoided. The above identified U.S. Patent describes a structure in which provision is made for protection of a resilient sealing element which is located to allow a press fit of a valve head with a valve seat in the closed position.
While such an arrangement has proven effective, the seal element is subject to deterioration over extended periods of time and erosion occurs at the exposed lower edge of the sealing element, which is the portion of the sealing element providing the sealing of the valve head when in its closed position. Accordingly, replacement of the seal element is necessary from time to time to ensure an effective valve closure. In the known structure the seal element is maintained in its seat and protected by a metallic sleeve which is installed with a press fit.
When it becomes apparent that the seal must be replaced, it is difficult, if not impossible, to remove the sleeve to allow removal of the damaged seal element and replacement of the seal element with the usual tools available on site.
Summary of the Invention It is an object of the present invention to provide a drill pipe float valve having a structure providing the maximum protection of the seal element while permitting ready changing of a seal element of the valve with the use of commonly available tools on site.
According to the present invention there is provided a drill pipe float valve including upper and a lower body portions having a threading connection therebetween for end-to-end connection so as to form a unitary cylindrical valve housing in a final threaded relationship for reception in an internal cavity in a string of connected drill pipe members. The body portions define together a continuous fluid passageway throughout the length of the unitary valve housing with one of the body portions defining an orifice area in the passageway. A
valve closure member is mounted in one of the body portions and defines a face for movement to a closed position in relation to the orifice area. An elastomeric seal element has a cylindrical portion positioned within the orifice with one end thereof defining an annular face for engagement by the face of the valve closure member in the closed position.
The seal element also has an annular flange extending externally from the cylindrical portion. One body portion of the valve defines an annular shoulder adjacent the orifice, and the other body portion defines a second annular shoulder. The shoulders are located to move into close facing proximity to each other as the body portions are threaded to the final threaded relationship so as to clamp therebetween the annular flange of the seal element.
More specifically, the invention relates to a float valve for inclusion in a drill pipe, and wherein the float valve includes a valve body having an outer surface for close reception in a counterbore of the drill pipe string. The float valve has an upper body portion and a lower body portion, the body portions having outer, aligned cylindrical surfaces of common diameter and aligned central passages therethrough for allowing fluid flow through the valve body. The lower body portion has an enlarged cylindrical, internally threaded opening in an upper end therein and terminating at a valve orifice at a lower end of the threaded opening, the valve orifice being defined by a short cylindrical section of less diameter than the internally threaded opening and being located between an upper circular shoulder portion above the valve orifice and a lower valve seat area therebelow. A valve closure member is contained in the central passage of the lower body portion below the valve orifice and provides a valve surface movable to a closed position immediately below the valve seat area. The upper body portion has a lower projection including an externally threaded section for reception in the threaded opening of the lower body portion so as to provide a connection of the upper and lower body portions and thus provide a unitary body when connected. The lower projection terminates in an extended cylindrical section which is below its externally threaded section and is of less diameter than both the externally threaded portion and the valve orifice. The lower projection of the upper portion is separated from the externally threaded portion thereof by an annular surface providing a lower shoulder of the upper body portion. An elastomeric seal element is formed by a cylindrical body having an upper lateral flange and a lower end defining a lower seal edge for engagement by the upper surface of the valve member. The cylindrical body of the seal element has an outer cylindrical surface for close reception within the valve orifice and an inner cylindrical surface for close reception of the extended cylindrical section of the upper body portion. T'he lateral flange of the seal element extends radially outward therefrom and defines upper and lower surfaces for engagement between the lower shoulder of the projection of the upper body portion and the upper circular shoulder of the orifice in the lower body portion. The cylindrical body of the seal element extending between the lower surface of the flange and the lower seal edge is of a length slightly greater than the short cylindrical section defining the valve orifice so that the lower seal edge is spaced a short distance between the lower edge of the valve orifice.
In a preferred form of the invention, the extended cylindrical section of the upper body portion has a length slightly less than the length of the total cylindrical portion of the seal element so that the lower seal edge of the seal element is spaced a short distance below the extended cylindrical section of the upper body member. In this arrangement, the externally cylindrical section of the upper body portion shields the seal element from the flow of fluid passing downwardly through the orifice.
Brief Description of Drawings Figure 1 is a cross sectional view of the drill pipe float valve of the present invention as located within a drill pipe;
Figure 2 is a cross sectional view of a prior art drill pipe float valve;
Figure 3 is an enlarged cross sectional view showing in greater detail the relationship of the essential elements of the present invention;
Figure 4 is yet a further enlargement of a portion of the valve in the area of the seal element as indicated in the circle A of Figure 3; and Figure 5 is a perspective view of the upper and lower body portions of the present invention in a separated condition.
Detailed Description of the Invention In Figure 1, the drill pipe float valve of the present invention, which is denoted generally by the reference number 10, is shown installed in a drill string or pipe 11 at a threaded connection 14 between an upper drill pipe member 12 and a lower drill pipe member 13. The drill string defines a continuous passage 18 therethrough for the flow of pressurized fluid to the lower end of the string. In the shown arrangement the lower drill pipe string member 13 is a drill collar and it provides an internally threaded female portion of the connection 14, commonly referred to as a box. It is to be appreciated that while reference is made herein to a drill pipe float valve, the float valve of the present invention is designed for being installed in different locations in a drill string, such as between two adjacent drill pipes, or as illustrated herein, within a drill collar which is at the lower end of the drill pipe string and is usually connected directly to the drill bit. A
counterbore 16 extends downwardly from the box or threaded portion 14 to a lower shoulder 17.
The float valve 10 has an outer diameter to be closely received within the counterbore 16 which has a length selected to permit the lower end of the float valve 10 to be spaced slightly from shoulder 17 of the lower drill pipe member 13 in order that the valve may float freely in the counterbore 16 between a lower end 15 of the upper drill pipe member 12 and the shoulder 17 when the male threaded portion or pin of the upper pipe member 12 is tightly threaded into the upper end of the lower drill pipe member I 3.
The float valve 10 is formed with a valve cage or body 20 which provides an outer cylindrical surface 23 machined for fitting closely within the counterbore 16.
The valve body 20 consists of upper body portion 21 and a lower body portion 22 which when assembled provide the unitary float valve of constant outer diameter. Adjacent the lower end of the outer surface of lower body portion 22 there is a peripheral groove 31 into which is fitted a flange of a bottom cushion member 32 of elastomeric material provided to engage the shoulder 17 of the counterbore 16. Near the top of the upper body portion 21 there is formed in the outer cylindrical surface of the valve body 20 a pair of spaced grooves 29,29, I S which are shaped to receive a pair of seal rings 30,30 of elastomeric material. The seal rings are orientated in opposite sealing directions so as together resist passage of fluid between the outer cylindrical surface 23 of the valve body 20 and the wall of the drill pipe member defining the counterbore 16.
As indicated, the upper body portion 21 and the lower body portion 22 are formed with common outer diameters so that together they have aligned outer cylindrical surfaces.
The upper and lower bodies also define concentrically disposed central passages 25 and 26 to provide the assembled valve 10 with a continuous fluid passageway therethrough. This passageway aligns with the passage 18 of the drill pipe 11, and as further described below, permits the flow of fluid downwardly through the drill pipe 11 when the pressure of the fluid above the valve is greater than downhole pressure in the well being drilled.
Referring briefly to the features of a commonly used float valve illustrated in Figure 2, it may be noted that this prior structure is provided with a flap valve fv which, when closed, provides an upper face for engagement with a lower annular face of a rubber-like seal element se. The seal element se is maintained in an orifice of the valve by a retainer sleeve rs which is installed within the valve body with a press fit. When the seal element se deteriorates or otherwise becomes worn or damaged in use so as to require replacement, it can only be removed by first driving the retainer sleeve rs from its seat.
Such an operation and the reseating of the retaining sleeve are extremely difficult to achieve particularly with tools normally available on site.
With particular reference to Figure 3, it may be noted that in the structure of the float valve 10 of the present invention, the assembled valve body 20 is formed of separate upper body portion 21 and lower body portion 22 connected by a threaded connection 24. The lower body portion 22 provides an enlarged internally threaded opening 40 extending downwardly from an upper end 38 of the lower body portion 22. In the illustrated embodiment, the lower body portion 22 has spaced below the threaded opening 40 thereof a portion defining a valve orifice area 41 which is of lesser diameter than the threaded opening. As shown, the valve orifice area 41 is provided by a short cylindrical wall section 42 located between an upper annular shoulder portion 43 above the orifice area 41 and a lower valve seat area 44 below the valve orifice.
Below the lower valve seat area 44, the lower body portion 22 forms an internal cylindrical cavity which provides the central passage 26. Mounted in this internal cylindrical cavity is a valve closure member 33 which is shown as being a flapper valve in the form of a flapper plate 34 having an upper surface providing a valve seal surface 37.
The flapper plate 34 is pivotally mounted within the internal cylindrical cavity of the lower body portion 22 by way of a pivot pin 35. A spring 36 normally urges the flapper plate to the orifice closure position as shown in Figures l and 3 in which the upper surface or valve seat surface 37 of the flapper plate 34 is in proximity to the valve seat area 44. The pressure exerted by the spring 36 to close the valve is not great but is calibrated to swing the valve to the closed position when the pressure in the fluid above the valve 10 is not greater than the fluid pressure below the valve 10. Increase in the pressure of the fluid downhole forces the plate into a more effective sealing relationship.
The upper body portion 21 includes a lower projection 50 providing an externally threaded section 51 for threading engagement within the internally threaded opening 40 of the lower body portion 22, the projection SO extending downwardly from a lower shoulder 49. Below the externally threaded section 51, the lower projection includes an extended cylindrical section 52 of less diameter than valve orifice 41 and terminating in a lower end in the form of an annular bottom surface 53 of the upper body portion 21. The extended cylindrical section 52 is of less diameter than the externally threaded section of the upper body portion and is separated therefrom by an annular lower shoulder 55.
A seal element 56 which is formed of elastomeric material has a cylindrical body 57 having an inner cylindrical surface 60 for close engagement with the external surface of the extended cylindrical section 52 at the lower end of the upper body portion 21, as best seen in Figures 4. At the upper end of the cylindrical body 57, there is provided an outwardly projecting, upper lateral flange 58, the upper surface 59 of which is coplanar with the top of the cylindrical body 57. A lower surface 62 of the lateral flange 58 is spaced from a lower seal edge 63 of the cylindrical body a distance slightly greater than the short cylindrical wall section 42 forming the valve orifice. The total inner length of the cylindrical body 57 is slightly greater than the length of the lower projection 50 which extends from the lower shoulder 55 to the annular bottom surface 53 of the lower projection of the upper body portion 21. Accordingly, a very short portion of the very lower part of the cylindrical body 57 of the seal element 56 projects below the valve seal area 44 of the orifice and also below the annular bottom surface 53 of the lower projection 50 of the upper body portion 21.
It may be observed that the thickness of the lateral flange 58 of the seal element is such in relation to the relative positions of the lower shoulder 55 of the upper body portion 21 and the upper annular shoulder 43 of the lower body portion 22 that as upper end 38 of the lower body portion 22 engages the lower shoulder 49 of the upper body portion 21, the shoulders 5_S and 43 of the upper body portion and the lower body portion, respectively, tightly engage the upper surface 59 and lower surface 62 of the lateral flange 58. The seal element is thus received in its final position with its lower seal edge 63 exposed slightly below the annular bottom surface 53 of the upper body portion 21 and the lower valve seat area 44 in the lower body portion 22. Thus, the lower seal edge 63 is positioned to be contacted by the upper valve seat surface 37 of the flapper plate in a sealing relationship.
With the illustrated relationship between the seal element 56 and the orifice defined by the valve orifice area 41 in the lower body portion 22 and the positioning of the extended cylindrical section 52 of the upper body portion 21 within the orifice area, the seal element 56 is protected from the flow issuing from the central passage 25 of the upper body portion 21 into the central passage 26 of the lower body portion.
The very upper end of the upper body portion 21 is provided with a pair of opposed flats 27,27 one of which is apparent in Figure 4, in order that the upper body portion 21 may be gripped between the jaws of a wrench so that on holding the lower portion, such as in the jaws of a vice, the two body portions can be separated. Accordingly, when it becomes apparent that the valve is not fully effective due to a damaged seal element, or if it is deemed advisable to change the seal element 56 at a time when the float valve is readily accessible, the upper body portion 21 can be quickly removed from the lower body portion and the old seal element 56 can be removed by hand. A new seal element need then only be slid over the extending cylindrical section 52 of the upper body portion 21 before it is rethreaded back into the internally threaded opening 40 of the lower body portion 22. As the threading is earned out the seal element 56 enters the valve orifice area 41 and proceeds to its final position as the lateral flange becomes clamped between the shoulders 43 and 55 on final tightening of the two body portions 21 and 22.
It will be apparent to those skilled in the art that various modifications to the preferred embodiment disclosed above without departing from the spirit of the invention as set forth in the appending claims.
Claims (3)
1. A drill pipe float valve comprising;
separate upper and a lower body portions having a threaded end-to-end connection therebetween to thereby form a unitary cylindrical valve housing in a final threaded relationship for reception in an internal cavity in a drill string;
said body portions defining together a continuous fluid passageway throughout the length of said unitary valve housing, one of said body portions defining a valve orifice in said passageway, a valve closure member mounted in one of said body portions and defining a face for movement to a closed position in relation to said orifice, an elastomeric seal element having a cylindrical portion positioned within said orifice and at one end defining at annular face for engagement by said face of said valve closure member in said closed position, said seal element also having an annular flange extending externally from said cylindrical portion, said one body portion defining an annular shoulder adjacent said orifice, the other body portion defining a second annular shoulder, said shoulders being located for movement into close facing proximity to each other as said upper and lower body portions are threaded to said final threaded relationship for thereby clamping said annular flange of said seal element therebetween.
separate upper and a lower body portions having a threaded end-to-end connection therebetween to thereby form a unitary cylindrical valve housing in a final threaded relationship for reception in an internal cavity in a drill string;
said body portions defining together a continuous fluid passageway throughout the length of said unitary valve housing, one of said body portions defining a valve orifice in said passageway, a valve closure member mounted in one of said body portions and defining a face for movement to a closed position in relation to said orifice, an elastomeric seal element having a cylindrical portion positioned within said orifice and at one end defining at annular face for engagement by said face of said valve closure member in said closed position, said seal element also having an annular flange extending externally from said cylindrical portion, said one body portion defining an annular shoulder adjacent said orifice, the other body portion defining a second annular shoulder, said shoulders being located for movement into close facing proximity to each other as said upper and lower body portions are threaded to said final threaded relationship for thereby clamping said annular flange of said seal element therebetween.
2. A float valve for inclusion in a drill pipe string, said float valve comprising:
a valve body having an outer surface for close reception in a counterbore of said drill pipe string and including an upper body portion and a lower body portion;
said body portions having outer, aligned cylindrical surfaces of common diameter and aligned central passages therethrough for allowing fluid flow through said valve body;
said lower body portion having an enlarged cylindrical, internally threaded opening in an upper end therein and terminating at a valve orifice at a lower end of said opening;
said valve orifice being defined by a short cylindrical wall section of lesser diameter than said internally threaded opening and located between an upper annular shoulder portion above said valve orifice and a lower valve seat area therebelow;
a valve closure member contained in said central passage of said lower body portion below said valve orifice and providing a valve surface movable to a closed position immediately below said valve seat area;
said upper body portion having a lower projection including an externally threaded section for reception in said threaded opening of said lower body portion to provide connection of said upper and lower body portions and thereby form a unitary valve body when connected;
said lower projection terminating in an extended cylindrical section below the externally threaded section thereof of lesser diameter than both said externally threaded portion of said lower member and said valve orifice;
said lower projection of said upper body portion being radially spaced from said externally threaded portion thereof by an annular surface providing a lower shoulder of said upper body portion; and an elastomeric seal element being formed by a cylindrical body having an upper lateral flange and a lower end defining a lower seal edge for engagement by said upper surface of said valve member in said closed position, said cylindrical body of said seal element having an outer cylindrical surface for close reception within said valve orifice and an inner cylindrical surface for close reception of said extended cylindrical section of said upper body portion;
said lateral flange of said seal element extending radially outward therefrom and defining upper and lower surfaces for respective engagement between said lower shoulder of said projection of said upper body portion and said upper circular shoulder of said orifice in said lower body portion;
said cylindrical portion of said seal element having a portion extending between said lower surface of said flange and said lower seal edge of a length slightly greater than the short cylindrical section defining said valve orifice whereby said lower seal edge is spaced a short distance between said lower edge of said valve orifice.
a valve body having an outer surface for close reception in a counterbore of said drill pipe string and including an upper body portion and a lower body portion;
said body portions having outer, aligned cylindrical surfaces of common diameter and aligned central passages therethrough for allowing fluid flow through said valve body;
said lower body portion having an enlarged cylindrical, internally threaded opening in an upper end therein and terminating at a valve orifice at a lower end of said opening;
said valve orifice being defined by a short cylindrical wall section of lesser diameter than said internally threaded opening and located between an upper annular shoulder portion above said valve orifice and a lower valve seat area therebelow;
a valve closure member contained in said central passage of said lower body portion below said valve orifice and providing a valve surface movable to a closed position immediately below said valve seat area;
said upper body portion having a lower projection including an externally threaded section for reception in said threaded opening of said lower body portion to provide connection of said upper and lower body portions and thereby form a unitary valve body when connected;
said lower projection terminating in an extended cylindrical section below the externally threaded section thereof of lesser diameter than both said externally threaded portion of said lower member and said valve orifice;
said lower projection of said upper body portion being radially spaced from said externally threaded portion thereof by an annular surface providing a lower shoulder of said upper body portion; and an elastomeric seal element being formed by a cylindrical body having an upper lateral flange and a lower end defining a lower seal edge for engagement by said upper surface of said valve member in said closed position, said cylindrical body of said seal element having an outer cylindrical surface for close reception within said valve orifice and an inner cylindrical surface for close reception of said extended cylindrical section of said upper body portion;
said lateral flange of said seal element extending radially outward therefrom and defining upper and lower surfaces for respective engagement between said lower shoulder of said projection of said upper body portion and said upper circular shoulder of said orifice in said lower body portion;
said cylindrical portion of said seal element having a portion extending between said lower surface of said flange and said lower seal edge of a length slightly greater than the short cylindrical section defining said valve orifice whereby said lower seal edge is spaced a short distance between said lower edge of said valve orifice.
3. A float valve as defined in claim 1, wherein;
said extended cylindrical section of said upper body portion has a length slightly less than the length of said cylindrical portion of said seal element whereby said lower seal edge of said seal element is spaced a short distance below said extended cylindrical section of said upper body member.
said extended cylindrical section of said upper body portion has a length slightly less than the length of said cylindrical portion of said seal element whereby said lower seal edge of said seal element is spaced a short distance below said extended cylindrical section of said upper body member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2491931 CA2491931A1 (en) | 2005-01-07 | 2005-01-07 | Drill pipe float valve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2491931 CA2491931A1 (en) | 2005-01-07 | 2005-01-07 | Drill pipe float valve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2491931A1 true CA2491931A1 (en) | 2006-07-07 |
Family
ID=36646255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2491931 Abandoned CA2491931A1 (en) | 2005-01-07 | 2005-01-07 | Drill pipe float valve |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2491931A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11421509B2 (en) | 2017-10-16 | 2022-08-23 | Pamala Ranee CRESS | High pressure float valve |
-
2005
- 2005-01-07 CA CA 2491931 patent/CA2491931A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11421509B2 (en) | 2017-10-16 | 2022-08-23 | Pamala Ranee CRESS | High pressure float valve |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |
Effective date: 20121221 |