This Application is a continuation-in-part of U.S. application S/N 567,737 filed August 15, 1990.

Related Application

This application is related to a co-pending application, S/N 89-05010, filed November 8, 1989 and entitled: "High Pressure Pipe Coupling" and to a co-pending application S/N 567,738 , filed August 15, 1990 and entitled "Plug Valve With Metal-To-Metal Sealing".

Field of the Invention This invention relates to a form of hemi-ball valve uti¬ lizing metal-to-metal sealing elements for throughout the construction so that the valve can be utilized with corrosive liquids and is capable of a pressure seal under both static and dynamic conditions of the valve. Background of the Invention

Ball valves and types or forms of ball valves which uti¬ lize a valve element with a spherical sealing surface are standard available products which are designed for a number of applications. The particular invention of this applica- tion is involved with a valve using a valve element with a spherical sealing surface segment and utilizing metal-to- metal pressure sealing means for a heavy duty valve which can be utilized in oil field operations.

Typically a valve of the type contemplated by the pre- sent invention includes a hollow valve body which contains valve element rotatable about a rotation axis and provided with a spherical sealing surface. The valve element typi¬ cally is rotatable through a 90° (1/4 turn) for a rapid full open or closed operation. Typically, the pressure seals which are utilized to seal the trunnions on the valve element and the closures in valves are made of Hycar or Viton, a synthetic rubber material, which are satisfactory for most applications. However, in some instances metal-to-metal seals would be preferable in valves because of resistance to corrosive fluids and resistance to temperature effects which causes deterioration and failure of elastomer products. Additionally, in valves, the rotation of the trunnions

relative to the elastomer seal tends to wear out the seals so that leaks occur.

With a spherical sealing surface on a valve element, a considerable number of valves utilize eccentric trunnion mountings to give leverage in providing a metal-to-metal seal between the spherical sealing surface on the valve element and the sealing seat in the valve body. However, concentrically mounted valve elements have always posed problems in sealing between the sealing surface and the sealing seat.

Metal-to-metal seals have heretofore been employed in pipe couplings for interconnecting flanges to one another. Current metal-to-metal seals in this type of use include the following. 1) The API flange - this is a widely used coupling for high pressure fluids and involves a face-to-face coupling of flanges with an interposed metal sealing member between the flanges. The metal sealing member is usually a flat faced seal that is crushed between two flat faced hubs on the flanges.

2) A "Grayloc" type connector - this connector is comprised of facing, metal seal ring, hubs and an annular clamp assembly and internal metal sealing ring resembling and inverted "T" in cross section is disposed between the hubs. The clamp assembly fits over the outer annular surface of the two facing hubs and is forced radially inward by making up the clamp bolts to draw the facing hubs together and to compress with the sealing ring rib between the hub surfaces. As the hubs are drawn together by the clamp assembly, the internal seal ring lips engage and deflect against the inner sealing surfaces on the hubs. The deflec¬ tion of the seal ring lips elastically preloads the lips of the seal ring against the inner sealing surfaces of the hubs thereby forming a preloaded seal. In use, internal pressure acts on the seal ring lips so that the sealing action of the lips is both preloaded and pressure-energized. However, if the internal pressure becomes sufficiently great to cause the facing hubs to be displaced or moved longitudinally of one

another, the seal ring lips will lose their sealing ability because the preloading sealing Compression between the hubs and the seal is lost. Also, the metal seal ring has a 20° (sometimes 25°) bevel so that the seal lips do not radially compensate for movement of the seal lips when the hubs are spread apart from one another.

3) "Weco" wing union - this coupler has metal-to-metal compression seals disposed between connector surfaces and uses a lip type elastomer replaceable seal to protect the metal primary seal.

4) A "dynetor" connector - this is a metal-to-metal connector coupling with a reusable annular metal seal. The annular metal seal has cylindrical ends so that some longitu¬ dinal expansion or spreading between the coupling pats can occur without losing the seal in the annular seal bores.

5) The Nicholson flange - this is an annular shaped gasket which is used between flanges and flange grooves. The flange seal, when compressed between flanges, will expand with longitudinal movement but the seal will fail because the gasket expands longitudinally and thus will fail at the gap.

6) The Nicholson lip C seal - this is a seal which depends upon point contact for sealing and is a round seal.

7) The Cameron AX or CX gasket illustrated in the 1988-99 Composite Catalog, pgs 683, 685 and 826. The AX and CX gasket is a tubular member which has an external taper on each end and sealing means which engage tapered surfaces in adjoining connectors.

Patent Art

Prior patent art includes: U.S. Patent 2,863,679 issued December 9, 1958;

U.S. Patent 3,628 ,812 issued December 21, 1971;

U.S. Patent 4,221,408 issued September 9, 1980;

U.S. Patent 4,384,730 issued May 24, 1973;

U.S. Patent 4,408,771 issued October 11, 1983; and U.S. Patent 4,353,560 issued October 12, 1982.

The Present Invention

The present invention is embodied in a metal-to-metal

seal system in a valve which utilizes metal sealing elements not only for sealing but also for providing energizing force to seat and to maintain the seal between a concentrically mounted spherically shaped valve element and a spherical shaped, annular valve seat in a valve body.

In the present invention, the valve element has a central spherical face between upper and lower trunnions. The spherical face has a smooth sealing surface located at a 90° rotational position relative to a flow port in the spherical face. The valve element is disposed in a valve body and rotationally mounted in the valve body so that the central spherical face is rotatable about a vertical rota¬ tional axis which intersects and is perpendicular to a hori¬ zontal central axis through inlet passages to the valve body. The spherical face contacts an annular metal sealing face on one end of a tubular seat member where the seat member is slidably mounted and centralized in the valve body with respect to the central axis. The bore through the seat member is part of the inlet flow passage. The other end of the seat member is in contact with two resilient annular metal sealing rings which are arranged to resiliently flex under an axial loading force. The annular sealing rings are loaded under an axial loading force by a wedge member which is disposed between the valve element and the valve body in a location on the side of the valve element opposite to the seat member. The wedge member serves to pre-load the spheri¬ cal face of the valve element on the annular seat member in an open or closed position of the valve element. The valve element, when closed, will seal against pressure in either direction across the valve element.

In the valve assembly, metal sealing elements are employed to seal the various valve elements with respect to the valve body so that the valve contains all metal-to-metal seals. In the present invention, the metal sealing elements provide internal and external sealing of the valve element sealing seat relative to the valve body. The arrangement of the metal seals is in conjunction with specific differential

pressure areas to create a positive differential seal area between the valve element sealing surface and its sealing seat in the valve body. This produces an effect whereby when either internal or external pressure acts on the valve seat, the pressure will urge the valve seat into sealing contact with the sealing surface on the valve element.

Description of the Drawings

FIG. 1 is a view in longitudinal cross section through a valve in which the present invention is embodied; FIG. 2 is a view in horizontal cross section taken along line 2-2 of FIG. 1;

FIG. 3 is a perspective view of the valve element of the present invention;

FIG. 4 is a view in cross section taken along line 4-4 of the wedge member shown in FIG. 6;

FIG. 5 is a perspective view of the wedge member of FIG. 6;

FIG. 6 is a one face view of a wedge member used in the valves of the present invention; FIG. 7 is a fragmentary view in cross section to illustrate a sealing mechanism between the spherical sealing surface and a sealing seat;

FIG. 8 is a fragmentary view in cross section to illustrate a sealing mechanism between the valve body and a sealing seat member;

FIG. 9 is a fragmentary view in cross section to illustrate a sealing mechanism between the valve body and a valve cap;

FIG. 10 is an enlarged fragmentary illustration of dif- ferential pressure areas in the valve;

FIG. 11 is a top view of the drive plate; and

FIG. 12 is a perspective view of the spacer element to illustrate its configuration.

Description of the Invention Referring now to FIG. 1 and FIG. 2, an elongated valve body 10 is illustrated with a central enlarged body portion 11. Aligned inlet and outlet passages 13,14 are located

along a central horizontal axis 15 and the valve body is adapted for coupling to pipes with its passages 13,14 in fluid communication therewith for conveying liquids. The central body portion 11 has a valve chamber generally disposed about a vertical rotational axis 17. The vertical rotational axis 17 intersects the central axis 15.

The configuration of the valve element 20 as shown in FIGS. 1, 2, 3 can best be depicted as a spherical ball with inner and outer spherical wall surfaces 21,22 and a vertical central axis 17a. The spherical ball is then split into two parts to define a "he i-ball" valve element 20 with an annu¬ lar end wall surface 24 (see FIG. 2) . The half ball or "hemi-ball" is then truncated at the top by a horizontal plane 25 which is normal to the central vertical axis 17a. The half ball is also truncated at the bottom by a horizontal plane 27 which is normal to the central axis 17a. Thus, the structure is a half ball member which is truncated by upper and lower planes 25,27 which are normal to a central vertical axis 17a. The half ball member may then be further con- sidered as divided by a vertical plane into two quarter segments, with one of the quarter segments containing a cylindrical opening 30 which aligns, in one position of the ball member in the valve body, with the flow passages 13,14. The other quarter segment presents an external smooth sealing surface for sealing on an annular valve seat. To rotate the half ball member or valve element 20, a radially extending notch 34 is provided in the upper portion of the ball member and the notch 34 cooperates with a lug 36 on a drive plate 37 (FIG. 1) to rotate or drive the ball member or valve element through an angle of 90° to open and to close the valve. In FIG. 2, there is a dashed line 34a which illustrates a central location of the lug 36 relative to the axis 15 for the opening 30 of the valve element. The opening 30 is angu¬ larly displaced 45° from the lug slot 34 so that a mechanical advantage is provided when opening the valve from a closed position.

The valve element 20 is supported by a core member 95 where the core member has an outer spherical surface portion

95a (see FIG. 2) which slidably supports the valve element 20. The core member 95 has an outer spherical configuration with truncated top and bottom flat surfaces and a central opening. As can be seen in FIG. 2, the ball member 20 can be rotated 90° from a valve open position where one part 24a of the end surface 24 on the valve element 20 engages a vertical stop face 38 on a wedge member 39 to a valve closed position where a diametrically disposed part 24b of the end surface 24 on the valve element 20 engages a vertical stop face 40 on the wedge member 39.

The wedge member 39 which is mounted in the valve chamber adjacent the outlet 14 is shown in three views in FIGS. 4-6 and includes a generally arcuate cylindrical wall at an upper end where the wall has an outer wall surface 42 and an inner arcuately curved wall surface 43. In the inner wall surface 43 there is a latching groove 44 of generally rectangular cross section. The arcuate cylindrical wall extends through an angle of 90° and terminates with the ver- tical end stop faces 38,40 (see FIG. 2) . Below the upper cylindrical wall is a transverse connecting section 45 which connects to a depending vertical wall 46. The wall 46 has a vertical forward planar surface 47 along a vertical plane and a rearward tapered surface 48 along an inclined plane to define a tapered element. A circular opening 50 in the wall 46 aligns with the passages 13,14 and the surface 48 is recessed to form parallel side surfaces 51 (see FIG. 2) .

Referring to FIG. 1 and FIG. 2, the wedge member 39 is disposed in the valve body with its tapered surface 48 in engagement with a tapered surface 52 on a tubular spacer ele¬ ment 54. The tapered surface 52 is in an inclined plane relative to vertical to conform to the inclined surface 48. The spacer element 54 is received in a counterbore 56 in the outlet passage 14 and cooperates with the wedge element 39 to maintain the forward vertical wedge surface 47 at a fixed location along the axis 15. The spacer element 54 has a "D" shaped outer profile which acts at the stop position for the wedge member 39 to insure that the bore 50 lines up with the

passages 13 and 14. (See FIG. 12). The upper flattened sur¬ face 54a of the spacer element 54 engages a transverse flat surface 45a on the wedge element 39 (see FIGS. 4-6). The transverse diametrical surface points 54c,54d engage the side surfaces 51 in the wedge element 39.

As shown in FIG. 1 and FIG. 2, the forward or outer spherical surface 22 of the valve element 20 engages an annu¬ lar spherical seal surface 58 on a tubular seating member 60 mounted in an enlarged diameter portion of the inlet passage 13. Referring briefly to FIG. 7, in a preassembly or pre¬ loaded condition, the curvature of the spherical surface 22 is the same as the curvature of the sealing surface 58 on an annular sealing lip portion 62 of the seating member 60 but inclined relative thereto. The lip portion 62 is formed by an annular recess 64 adjacent to the end of the seating member 60 and the top 63 of the lip is disposed to engage the surface of the valve element in annular contact therewith about the opening 30. When the valve element 20 is moved axially along the axis 15 relative to the seating member 60, the metal lip 62 flexes until the surfaces 22 and 58 are in conforming engagement in a metal-to-metal sealing condition with the lip 62 providing a resilient biasing force to main¬ tain the contact of the surfaces 22 and 58.

Referring again to FIGS. 1 and 2, the seating member 60 has an external annular groove 66 midway of its length which receives a centralizing ring for urging the seating member 60 to a central position in the bore 68 which is an enlarged diameter coaxial extension of passage 13. The bore 70 of the seating member is aligned with the inlet passage 13 and is of equal diameter therewith. The end surfaces 72,74 of the seating member 60 are annular 45° bevels, inwardly and out¬ wardly facing respectively, which form a generally pointed annular end. (See FIG. 8) . The valve body has an internal recess 76 adjacent to the bore 68 intermediate the enlarged diameter portion of the inlet 13 and its enlarged diameter bore portion 68 and in a facing relationship to the outward facing annular bevel 74. The valve body 10 is provided with similar annular beveled surfaces 78,80. The facing surfaces

72 and 78 which face inwardly toward the valve passage form an inner annular "V" shaped sealing groove 82 and the outward facing surfaces 74 and 80 form an outer annular "V" shaped groove which opens to the annular recess 76. 5 Referring now to FIG. 8, an enlarged detail is shown for the recess formed by the inner groove 82 and for the recess 76. The parts are shown in an "unloaded" condition in FIG. 8 where the recess 82 contains an annular "V" shaped resilient metal sealing means 86 and the recess 76 contains an annular 10 "V" shaped resilient metal sealing means 88. The sealing means 86 and 88 are described in detail in a co-pending application S/N 635,568 filed Nov. 8, 1989. Briefly, the sealing means 86 and 88 are sealing rings with a generally V shaped configuration in cross section which have 15 a larger included angle between the outer surfaces 88a,88b of the legs or "wings" of the sealing ring than the 90° angle formed between the beveled surfaces 74 and 80. Where the seating member 60 is moved axially relative to the valve body 10, the sealing means 86,88 will be flexed and the surfaces 20 88a,80 and the surfaces 88b and 74, for example, will be urged into metal-to-metal conforming contact with the flexure of the sealing means 86,88 providing a sealing force. A tubular retainer member 90 in accommodating recesses in the valve body and seating member 60 provides for bore continuity 25 between the passage 13 and the bore 70 of the seating member. If liquids should access the recess 82 or 76, the sealing means 86,88 provide a tight seal against liquid leakage in both directions.

With respect to the sealing effect of the sealing means 0 86 and 88, reference is made to an exaggerated detail in FIG. 10. When the valve element 20 is in a closed position, there is an annular area A which is defined between the bore 68 and the contact point of the circular tip 63 of the seat 62 which provides a differential area for maintaining a seal on 5 the valve seat when the external pressure on the valve seat is greater than the internal pressure. An annular area A is defined by the contact point 63a of the seat 62 with the valve element 20 and the contact point of the sealing means

_ _

88 which provides a differential area for maintaining a seal on the valve seat when the internal pressure on the valve seat is greater than the external pressure.

Referring again to FIGS. 1 and 11, the drive plate 37 is attached or coupled to the top of the valve element 20 and has a center, square shaped socket 92 which receives a square shaped socket drive 94 on a drive stem 96. The socket 92 is aligned so that its sides are parallel to the axis 15 in the open and closed position of the valve. As shown in FIG. 11, the drive plate 37 has segmented openings 37a,37b to either side of the solid lug portion 36 which fits into the slot 34 of the valve element. The bottom surface 27 of the valve element 20 sits on a center post 92a of a cylindrically shaped bearing plate 92c. The bearing plate 92c has a recessed surface 92b to access liquid to the recess 76.

The drive stem 96 of the valve element extends through a stem bore 98 in a top cap member 100. In the stem bore 98 is an annular recess 102 for a centralizing ring member and an annular recess 104 for a thrust bearing. At the lower end of the stem bore 98 is a recess and an outwardly tapered section 106 which is disposed adjacent to an annular sealing recess 108 formed by an enlargement of the stem bore 98. Disposed in the recess 108 is an annular resilient metal sealing means 112. As shown in enlarged fragmentary view in FIG. 9, the sealing means 112 is an annular V shaped member of resilient metal such as Inconel 718. The sealing means 112 has a "V" shaped configuration in radial cross section and an included angle between outer convergent surfaces 112a and 112b of about 81° while the included angle between a downward facing annular sealing surface 114 of the valve bonnet 100 and the sealing surface 109 of the tapered section 106 of the drive stem is 75°. When the top cap 100 is moved axially of the stem during assembly, the sealing means 112 moves from the "unloaded" positions shown in FIG. 9 to a loaded condition where the legs or "wings" of the sealing means 112 are flexed to exert a metal-to-metal sealing force between the surfaces 112a and 114 and between the surfaces 112b and 109. Internal pressure in the recess 108 will further energize the sealing

effect of the sealing means. The sealing means 112 which is a rotative metal-to-metal seal is further described in a co- pending application S/N 567,738, filed August 15, 1990 (on the same date as this application by the same inventor) . The top cap member 100 is threadedly received in an opening in the top of the valve body 10 as shown by the threaded connection 120. On the lower end of the top cap member 100 is an annular lip part 122 with an annular lug part 124. The lug part 124 interfits with the lug recess 44 in the wedge member 39. Thus, in assembly the cylindrical wall of the wedge member 39 is confined between the cylindri¬ cal bore 130 which forms part of the opening in the top of the valve body and the lip part 122 and lug part 124 of the top cap 100. The top cap 100 is pressure sealed with respect to the valve body by a "V" shaped annular sealing means 132 which is received in an external downwardly opening annular recess 133 formed in the cap 100. In the recess 133 is an annular sealing surface which is disposed at an angle of 90° with respect to another sealing surface formed in the valve body and between which the sealing means 132 is provided to establish a seal for basically the same type of seal as described with respect to FIG. 8. In assembly, the sealing means 132 is moved from an "unloaded" to a "loaded" condition by flexing the metal of the sealing means and providing a metal-to-metal seal.

It will be appreciated that in assembly, the attachment of the top cap 100 moves the wedge member 39 into a wedging relationship with the spacer 54 and the core member 95 in the sealing element 20. This produces an axial movement of the sealing element 20 and the seating member to pre-load the seals 86,88 and 62. When the top cap is in its final posi¬ tion, the seals 132 and 112 are pre-loaded and the bores 30 and 54a are aligned with the bores 13 and 14 (see FIG. 1) while the vertical stop surfaes 38 and 40 are aligned by the surface portions 54(c) and 54(d) (see FIG. 12) located in between the wedge surfaces 51.

As can be appreciated from FIG. 2 the ball member 20 can

be rotated through one-quarter turn or 90° to open or close the passage 13. The surfaces 38 and 40 of the wedge member 39 provide a positive stop for the valve element.

From the foregoing description, it can be appreciated that the valve system of the present invention embodies metal-to-metal seals to provide a valve seat to body seal and also act as an energizing mechanism for the seat to sphere surface seal. The valve incorporates a single seat sealing mechanism to create a seat to spherical surface seal, irrespective of whether there is internal pressure or exter¬ nal pressure on the seat, when the valve is in the closed position.

When the valve mechanism is in the open position the metal seals, the valve seat, the valve element, the wedge and the spacer are energized by the V shaped seals which are sub¬ jected to axial compressive load by the introduction of the wedge member 39 between the core member 95 and the spacer element 54. The wedge is inserted and removed by utilizing the top cap which has a mating "tongue and groove" connec- tion.

When the top cap is fully screwed into position in the valve body, the top cap energizes the metal-to-metal seal with the valve body, the metal-to-metal seal with the stem and energizes the metal-to-metal seals in the body/seat seal and seat to hemi-ball seal.

The valve element rotates coaxially with the valve stem to accomplish the opening/closing operations. The drive mechanism between the hemi-ball and the stem is via the drive plate which cooperates with drive lugs on the hemi-ball and the square drive pin on the bottom end of the stem.

The seat to hemi-ball seal mechanisms "flexes" the seal to contact the hemi-ball all along the contact face. This ensures that both the inner and outer most contact points are simultaneously in sealing contact with the hemi-ball (valve element 20) .

To operate the valve mechanism from open to close, the drive stem 96 is rotated clockwise ninety (90) degrees from the full open position. The hemi-ball (valve element 20)

rotates concentrically between the core member 95 and the seating member (which remain stationary) until the vertical end face 24 of the hemi-ball (valve element 20) contacts the cooperating stop face 40 of the wedge member 39 and the valve is in closed condition. When pressure is internal to the seating member 60 in the passage 13, the cavity and "downstream" line pressure in passage 14 is bled to zero. The sealing means 72 between the seating member and body 10 is subject to internal pressure and the resulting hydrostatic end loads will provide an increased seal between the sealing means 72 and the body 10 and the resultant thrust will urge the seating member to increased sealing contact with the hemi-ball (valve element 20). The core member 95, the member 39 and the spacer element 54 merely act to support the seal elements and hold the axial alignment. Cavity pressure can¬ not be trapped behind the core since there are no sealing elements to stop the cavity pressure from bleeding off.

To open the valve against differential pressure, the drive stem 96 is turned counterclockwise ninety (90) degrees to the fully open position. When the hemi-ball (valve ele¬ ment 20) has moved sufficiently to allow the hole 30 in it to break sealing engagement with the seating member, the pressure will be equalized across the system and the torque to operate the valve will drop significantly. The posi- tioning of the drive lugs on the hemi-ball (valve element 20) creates a mechanical advantage when operating the hemi-ball (valve element 20) against differential pressures.

When the valve is closed and the differential pressure is on the "downstream" side (passage 14) of the seating member relating to the hemi-ball (valve element 20) seal, the sealing means 74 is subjected to external pressure which will cause the seating member to be urged toward the hemi-ball (valve element 20) by the differential pressure area and will cause the pressure to maintain the seat-to-hemi-ball sealing contact. The cavity pressure will cause "lift" on the valve stem 96 due to the sealing means connection. This thrust load is absorbed in the top cap by the t.irust bearing. The thrust bearing has two functions: a) to hold the stem in

_ _

position, and b) to reduce friction effect during rotation under differential cavity pressure.

In the present invention, the sealing means provide internal and external sealability of seat to body connection. The use of sealing means in conjunction with specific dif¬ ferential areas to create positive differential seal areas between the seat and hemi-ball so that either internal or external pressure will urge the seat to the hemi-ball and not vice versa. This means that the design relies on the flexure of the annular metal sealing rings to maintain the sealing mechanism.

The concentric hemi-spherical hollow ball is used as both the driver/seal mechanism. The position of the drive lugs provide a mechanical advantage when operating the hemi- ball from the closed/differential pressure position. The square drive at the lower end of stem in the drive plate allows axial "float" when the valve is in the closed position with the differential pressure. Valve does not rely on the seal elements being "locked" together axially in the closed position, but utilizes axial "float" to allow annular metal sealing rings to work properly whether pressure is pre¬ sent or not.

It will be apparent to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is enclosed in the drawings and specifications, but only as indicated in the appended claims.