US 3684013 A
A well pipe string valve either for limiting the fluid flow rate downwardly, in which case a pressure pulse may be created within the pipe string, or for preventing any flow in an upward direction, in which case the valve serves the same purpose as a conventional one-way check valve. In the former mode, a plurality of discrete congruent sections forming an upwardly pointing cone are secured across the pipe string and pivotally mounted as the bases thereof, being resiliently biased away from one another in an open position. As the downward flow rate increases, the sections engage one another to form the cone shape, assuming the valve closed position; and a pressure pulse may be created within the pipe string above the valve although a pressure stabilizing orifice is provided through the cone so that a small amount of fluid will continually bleed past the valve. Essentially the same arrangement is used as the back flow check valve except that the cone is inverted, no orifice is provided therethrough, and the cone sections are resiliently biased toward the closed position
Claims available in
Description (OCR text may contain errors)
United States Patent Brown WELL PIPE STRING VALVE Inventor: Henry C. Brown, Odessa, Tex.
Brown Well Service & Supply Com pany, Odessa, Tex.
Filed: Jan. 19, 1971 Appl. No.: 107,784
Primary Examiner--James A. Leppink Attorney Arnnld. White & Durkee 151 3,684,013 [4 1 Aug. 15, 1972 ABSTRACT A well pipe string valve either for limiting the fluid flow rate downwardly, in which case a pressure pulse may be created within the pipe string, or for preventing any flow in an upward direction, in which case the valve serves the same purpose as a conventional oneway check valve. In the former mode, a plurality of discrete congruent sections forming an upwardly pointing cone are secured across the pipe string and pivotally mounted as the bases thereof, being resiliently biased away from one another in an open position. As the downward flow rate increases, the sections engage one another to form the cone shape, assuming the valve closed position; and a pressure pulse may be created within the pipe string above the valve although a pressure stabilizing orifice is provided through the cone so that a small amount of fluid will continually bleed past the valve. Essentially the same arrangement is used as the back flow check valve except that the cone is inverted, no orifice is provided therethrough, and the cone sections are resiliently biased toward the closed position 10 Claims. 3 Drawing Figures PATENTEDAUG 15 1912 SHEET 1 (IF 3 Henry C. Brown IN VE N 70/? FIG] ATTORNE Y5 PATENTEDAUE 15 m2 3,684,013
sum 2 or 5 Hehry C Brown IN VE N TOR FIG. 2 BY MMMM wee ATTORNEYS PATENTEDAUG 15 I972 SHEEI 3 or 3 Henry C. Brown INVENTOR ATTORNEYS WELL PIPE STRING VALVE BACKGROUND OF THE INVENTION This invention relates generally to well apparatus, and more particularly to valves for limiting the flow in a well pipe string.
The prior art has heretofore recognized the desirability of plugging or sealing the lower end of a pipe string as it is being lowered into a well bore to thereby prevent the string from becoming filled with well fluid. Such back flow of well fluid into the string may be effectively prevented by utilization of a shoe having a unidirectional check valve therein.
The prior art has also recognized an inherent advantage of employing such a check valve to maintain a seal at or near the bottom of a long string of pipe. That is, when the pipe string is lowered into a well bore, the empty string will have an increased buoyancy and will be partially supported by the hydrostatic pressure of the well fluid, which includes mud, water, oil, and other fluid ordinarily present in the well bore after drilling. By that manner of lowering the string called floating, the displacement of the well fluid by the string produces a buoyant effect so that the resultant force on the rig from the weight of the string may be materially reduced. Since the pipe string may be several thousand feet long and weigh many tons, the buoyant effect may become a vital engineering consideration.
One example of a prior art float valve unit is US. Pat. No. 3,473,609, issued to Richard H. Allen on Oct. 21, 1969, wherein it is disclosed that, by providing a float valve arranged to permit, downward flow of fluid through the pipe and to prevent upward fluid flow therethrough, the entire pipe string can be floated down the well bore to the intended depth. Upon arrival at such depth, a cement slurry can be pumped down through the pipe and out through the valve to fill the annular space between the outside of the pipe and the well bore, with the float valve serving to prevent any reverse flow of cement back up the pipe under the influence of the hydrostatic pressure of the uncured cement at the lower end of the pipe string. Allens float valve unit is pressure releasable; that is, the application of a large pressure pulse will cause the unit to shear away from the pipe string.
Frequently, after the string is run into the well bore to the desired depth but before the cement is introduced, it is desirable or necessary to set a hanger or packer and thereby support the string during the cementing process. Such hanger or packer setting operations may be readily effected by the application of a high pressure for a brief period of time to actuate a mechanism, such as a hydraulically set liner hanger. Moreover, it may be convenient to apply such a pressure pulse via the interior of the pipe string. But prior art float valve units, such as that disclosed by Allen, do not have the capability of retaining such a pressure pulse within the pipe string, since fluid introduced into the string under pressure will simply flow down through the string, there being no valve means to restrict such downward flow due to the subsequent cementing operation, and/or the unit itself will shear away. It is also contemplated that there may be other reasons for applying a pressure pulse to the interior of the pipe string from time to time in addition to the actuation of a liner hanger mechanism. Accordingly, for some well completion operations, a second valve, in addition to the customary back flow check valve, may be required.
Moreover, the importance of the function performed by the back flow check valves is sufficiently great to require an extremely reliable and dependable check valve structure which will function satisfactorily downhole in a well.
SUMMARY OF THE INVENTION The present invention contemplates a valve for limit ing the flow of fluid through a well pipe string wherein the valve is in the form of a cone positioned across the pipe string with the apex of the cone pointing in a direction opposite the flow to be limited. The cone is divided into a plurality of discrete congruent sections which are pivotal about the bases thereof into or away from engagement with one another. The sections are resiliently biased open when the valve is to be used to limit downward flow; but, closed when used as a flowback check valve to prevent upward flow. The sections may be made of neoprene rubber and provided with bumpers to limit the open position movement. The resilient bias may be provided by coil springs whose compression may be manually adjusted. In the embodi-x ment for limiting downward flow, a pressure stabilizing orifice may be provided through the cone.
BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed drawings when considered in connection with the accompanying drawings in which like reference characters designate identical or corresponding parts throughout the several views and wherein:
FIG. 1 is an elevation view, partly in section, of one embodiment of the valve of the present invention adapted for providinga pressure pulse within the pipe string and shown in the closed position; and
FIG. 2 is an elevation view, partly in section, of another embodiment of the valve of the present invention also adapted for providing a pressure pulse within the pipe string but shown in the open position;
FIG. 3 is an elevation view, partly in section, of yet another embodiment of the valve of the present invention adapted for use as a back flow check valve and shown in the closed position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and more particularly to FIG. 1 thereof, there is shown a valve 10 which may be secured within and across a tubular well pipe string in an end shoe or otherwise by any convenient means, such as tubular coupling sleeve l2,preferably steel or the like, having threads at each end. Of course, an externally threaded, tubular body 14 of valve 10 may be screwed into an internally threaded portion of the pipe string itself, so that, for purposes of this invention, the tubular coupling sleeve and the pipe string may be referred to interchangeably. It should be apparent that variety of other well-known means for securing the valve within and across a pipe string may be employed without departing from the spirit or scope of the present invention.
Body 14, which may be brass, cast iron, or the like, is externally threaded around the outer cylindrical surface proximate the base thereof, and a wrench slot 16 may be conveniently provided in the base end surface to enable the valve to be tightly screwed into coupling sleeve 12. Both cylindrical surfaces of body 14 are externally and internally relieved opposite the base thereof as at 18 and 20, respectively, and an annular groove 22 is formed in the end surface opposite the base. A plurality of axially extending, internally threaded through bores 24 are provided in body 14 proximate the inner cylindrical surface thereof.
An annular sealing grommet 26, made of neoprene rubber or the like, is shaped to matingly engage the aforementioned relieved surfaces and groove in body 14 and has a plurality of axially extending through bores adapted to be aligned with bores 24 in the body. The diameter of the inner cylindrical surface of grommet 26 preferably is the same as that of body 14. However, though the diameter of most of the outer cylindrical surface of the grommet is slightly smaller than that of the body, an angularly externally protruding sealing flange 28 has a natural outside diameter larger than that of body 14, so that the flange 28 will firmly abut the inside cylindrical surface of coupling sleeve 12 in a sealing relationship therewith. Thus, according to the preferred embodiment, grommet 26, which may or may not be bonded to body 14, provides a fluid seal between the body and the coupling sleeve; but it should be understood that the fluid seal may be effected by other well-known techniques, such as the use of O-rings or the like.
A generally conically shaped member 30 is formed of a plurality of discrete congruent sections 32, each having at least one protruding bumper means, such as nipple 34, adaptable to abut against the inner cylindrical surface of sleeve 12. Each section 32, principally made of neoprene rubber or the like, is secured to grommet 26 and in turn to body 14 by means of a flat strap spring 36, a major length 38 of which is embedded in the section and a minor length 40 of which is embedded in that portion of the grommet disposed in groove 22 in the body, according to the embodiment shown in FIG. 1. The congruent sections are so disposed to matingly engage one another in a fluidly sealed relationship as may be seen in FIG. 1 wherein the base end surface of conical member 30 is shown abutting the upper end surface of grommet 26 in a fluidly sealed relationship. The conical member is internally conically relieved near the base thereof as at 42, and a central, generally coaxial pressure stabilizing orifice, such as bore 44, may be provided therethrough. According to the preferred embodiment, there are two sections 32, but the conical member may be formed of more than two sections.
The resilient bias of strap springs 36 toward the closed position shown in FIG. 1 is opposed by the resilient bias of compressed coil springs 46 acting through plunger pins 48 toward the open position which may be appreciated from FIG. 2. There is at least one spring-plunger pin arrangement for each section 32. The resilient bias provided by springs 46 may be manually adjusted by any convenient means, such as externally threaded adjusting studs 50 screwed into bores 24.
Other means for securing and/or biasing sections 32 may be used within the contemplation of the invention, and one example is shown in FIG. 2. In FIG. 2, embedded flat strap spring 36 has been replaced by hinge spring 36', a major length 38 of which is embedded in section 32 and a minor length 40 of which is disposed in a hinge pocket provided by groove 22 in body 14 and apertures appropriately provided in grommet 26. Hinge spring 36' is appropriately secured to a hinge pin 52 provided in groove 22 by any convenient means, such as welding an inverted U-shaped member to the base of the groove.
The embodiments of valve 10 shown in FIGS. 1 and 2 are adaptable for use in a well pipe string for limiting the flow of fluid downwardly therethrough and, accordingly, for permitting the creation of a pulse of pressure with the pipe string above the valve. The valve 10 is screwed into the pipe string or into coupling sleeve 12 and in turn into the pipe string, and it is tightened therein by means of wrench slot 16. Studs 24 are adjusted until a resultant resilient of force of a predetermined magnitude, biased toward the open position, is achieved, at which point the valve will assume its open position with nipples 34 abutting against sleeve 12 shown in FIG. 2. The magnitude of that resilient force is proportioned to the maximum flow rate before which the valve assumes its closed position as shown in FIG. 1. The closing action provided by the fluid flow results from the downstream decrease in pressure as the fluid is forced through a constricted area. The pressure stabilizing orifice, shown as bore 44 in FIG. 1, is preferably included so that, even with the valve closed upon the application of a large flow rate, a small quantity of fluid will bleed off past the valve; in that manner the pressure pulse above the valve may be gradually relieved, to reopen the valve for the passage of fluid downwardly therethrough at flow rates below the critical threshold level. Of course, the orifice need not be included if there is provided some other means for relieving the pressure; if not, the valve will not open since the trapped pressure pulse will keep the valve closed.
In FIG. 3, there is shown an embodiment of the valve of the present invention adaptable for use in a pipe string as a back flow check valve. The embodiment shown in FIG. 3 is quite similar to that shown in FIG. 2, the principal differences being that the valve is inverted with respect to the pipe string, that there is no pressure stabilizing orifice since the back flow check valve is ordinarily employed to shut off the entirety of the back flow, and that a different resilient biasing means is employed to provide a resultant resilient force, biased toward the closed position.
To effect the latter difference, the inner cylindrical surface of body 14 is relieved at each end thereof as at 20', instead of merely opposite the base end, and axially extending through bores 24' are preferably smooth, not threaded. Embedded into each section 32 is a portion of at least one anchor ring 54 to which there is fastened a hook bolt 56. Each hook bolt passes through bore 24' and an appropriately aligned opening 58 in a washer 60, and an adjusting nut 62 is screwed on to the externally threaded straight end of the hook bolt. A compressed coil spring 46 circumscribes each hook bolt 56 between an internal flange 64 on body 14 and washer 60 so that the amount of resilient force biasing the valve toward the closed position may be increased or decreased by screwing the adjusting nut on to or off of the hook bolt, respectively. Of course, here again, variations in the biasing means may be employed.
The back flow check valve operation of the embodiment shown in FIG. 3 is readily apparent. In essence, the valve is merely a one-way valve, permitting flow only in a downward direction when the downward pressure is sufficient to overcome the resilient force biasing the valve toward the closed position. Since the valve is biased to close in the absence of any external pressure and since the application of pressure from below the valve also tends to force the sections toward the closed position, there can be no upward flow.
Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
What is claimed is:
1. Valve means for use in a tubular well pipe string for limiting the flow of fluid therethrough, the valve means comprising;
a conically shaped member adapted to be coaxially secured within and across the pipe string with the apex of the cone pointing in a direction opposite that of the flow to be limited;
said conically shaped member being formed by a plurality of discrete congruent sections matingly engageable with one another in a first position to assume the conical shape;
said sections being outwardly pivotal from said first position about axes proximate the outer periphery of the base of the cone and substantially tangential therewith to a second position in which said sections are separated from one another;
said sections collectively constituting both a valve and valve seat, which valve is seated in a closed relationship when said sections are in said first position and is open when said sections are in said second position; and
means for resiliently biasing said sections toward one of said first and second positions.
2. The apparatus of claim 1 wherein said biasing means biases said sections toward said second position.
3. The apparatus of claim 2wherein each of said sec tions is secured to the pipe string by means comprising a leaf spring.
4. The apparatus of claim 2 wherein said biasing means comprises a plurality of coil springs.
5. The apparatus of claim 4 further comprising means for adjusting the force exerted by said coil springs.
6. The apparatus of claim 5' wherein said adjusting comprises a threaded adjusting member.
7. The apparatus of claim 2 further comprising at least one protruding bumper means on the exterior surface of each of said sections for bearing against the interior surface of the pipe string when said sections are in said second position to serve as a stop.
8, The apparatus of claim 2 wherein said conically shaped member is provided with a central, generally coaxial orifice therethrough.
9. The apparatus of claim 2 wherein said sections are principlally neoprene rubber.
10. he apparatus of claim 1 wherein said biasing means biases said sections toward said first position.