Pipe connector apparatus

Apparatus for connecting a cylindrical first member to a second member which may comprise: a tubular body adapted to receive one end of the first member and for connection to the second member; an annular seal assembly carried by the body and movable from a relaxed position, in which one end of the first member may be axially received therein, to a compressed position, sealingly engaging one end of the first member; a seal load ring engageable with the seal assembly and axially movable relative to the body for moving the seal assembly to its compressed position; a gripper assembly axially spaced from the seal assembly and movable from a radially expanded position in which the first member may be axially received by and displaced from the body, to a radially contracted position gripping the exterior of the first member and preventing its axial displacement from the body; and a gripper load ring engageable with the gripper assembly and axially movable relative to the body for moving the gripper assembly to its contracted position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to pipe connector apparatus and methods of 
installation. Specifically, it pertains to apparatus and installation 
methods for connecting pipes or conduits in particularly difficult 
environments, e.g. subsea environments. 
2. Description of the Prior Art 
It is known to connect pipes using tapered slip wedges and correspondingly 
tapered slip bowls for forcing the slip wedges from a radially expanded 
position, in which a pipe member may be received therein, to a radially 
contracted position in which the slips grip the exterior of the pipe 
firmly clamping or wedging the pipe in a fixed position. In prior art 
connectors, the slips are moved to the gripping or clamped position by 
relative movement of the slip bowl and slips. Such movement is generally 
effected by application of fluid under pressure to an annular piston or a 
plurality of piston rams arranged around the axis of the pipe connector. 
Examples of such prior art apparatus may be seen in U.S. Pat. Nos. 
3,393,926; 3,704,033 and 3,986,728. 
In subaquatic environments, hydraulic pipe connectors have the advantage of 
requiring only that a diver connect the source of hydraulic pressure to a 
pressure port on the connector to enable slip wedges to be forced into an 
engaged position to clamp the connector against the pipe. However, such 
arrangements have a disadvantage in that when the hydraulic pressure 
source is later disconnected from the pipe connector, there are problems 
of sealing against escape of hydraulic fluid in order to prevent 
disengagement of the slips. Furthermore, such connectors are relatively 
expensive and with continuing development in underwater welding, may not 
remain competitive for many years. 
To eliminate the problems associated with hydraulic actuation, connectors 
have been developed for actuation by non-return mechanical means. In U.S. 
Pat. No. 3,999,782, a connector is disclosed in which the slips are driven 
apart by a screw arrangement, comprising thrust sleeves threadedly 
engageable with a common drive sleeve. The drive sleeve may be driven by a 
worm wheel arrangement so that as the worm is rotated, the worm wheel 
rotates the drive sleeve to drive the thrust sleeves and slips away from 
the worm wheel by virtue of opposed hand threaded interengagement between 
the thrust sleeve and the drive sleeve. Another but more simple 
mechanically actuated connector is described and claimed in co-pending 
United States Patent Application Ser. No. 788,159. 
Even though recently developed mechanical connectors have eliminated some 
of the problems associated with hydraulic connectors, they do not provide 
the ultimate answer in all connector applications. Furthermore, while they 
may be less expensive to install and maintain than hydraulic connectors, 
they are still relatively expensive and may not long compete with improved 
underwater welding processes. Furthermore, while some pipe connectors of 
the prior art provide means for further tightening of the annular seals 
associated therewith, such means could be improved in reliability and 
effectiveness. 
SUMMARY OF THE INVENTION 
In the present invention, a pipe connector is provided for connecting a 
first pipe member to a second pipe member including a tubular body adapted 
to receive one end of the first pipe member and provided with means for 
connecting the body to the second pipe member. An annular seal assembly is 
carried by the body for movement from a relaxed position, in which one end 
of the first pipe member may be axially received therein, to a compressed 
position, sealingly engaging the end of the first member. A gripper 
assembly is axially spaced from the seal assembly for movement from a 
radially expanded position in which the first pipe member may be axially 
received by and displaced from the body, to a radially contracted position 
gripping the exterior of the first pipe member and preventing its axial 
displacement from the body. An actuating assembly is carried by the body 
and includes a gripper load ring engageable with the gripper assembly and 
axially movable relative to the body for moving the gripper assembly to 
its contracted position. The actuating assembly also includes a seal load 
ring engageable with the seal assembly and axially movable relative to the 
body for moving the seal assembly to its compressed position. 
The actuating assembly includes means for simultaneously applying axial 
forces to the gripper load ring and the seal load ring for effecting axial 
movements thereof. The actuating assembly may also include means for 
applying additional axial forces to the seal load ring without applying 
additional forces to the gripper load ring. 
The connector of the present invention eliminates some of the major 
problems associated with hydraulic connectors, namely subsequent 
disengagement of the slips and leaks resulting therefrom. In addition, it 
offers means of subsequently applying additional forces to the seal 
assembly to stop leaks which may occur after extended use. Its 
manufacture, operation and maintenance are substantially improved over 
connectors of the prior art. Many other objects and advantages of the 
invention will be apparent from the description which follows in 
conjunction with the accompanying drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring first to FIGS. 1 and 2, there is shown a connector according to a 
preferred embodiment of the invention. The connector comprises a tubular 
body 1, an annular seal assembly 2, a gripper assembly 3, seal load ring 4 
and gripper load ring 5. 
The tubular body 1 may be provided with internal threads 11 for threaded 
connection with a pipe member 12. The body is counterbored at 12 so as to 
receive one end of another pipe member 13. The annular shoulder 14 created 
by the counterbore 12 limits the insertion of the end of pipe member 13 
therein. The tubular body 1 is further counterbored at 15 to receive the 
annular seal assembly 2. Counterbore 15 also provides an annular shoulder 
16 against which the seal assembly 2 may bear. 
Externally, the body member 1 may be tapered as at 17 to reduce its weight 
and streamline its appearance. A plurality of lifting eyes 18 may be 
welded around the tapered exterior of the body member 1 for connection of 
lifting attachments or the like such as the screw pin anchor shackle 
illustrated by dotted lines at 19. A plurality of radially disposed and 
threaded holes 20 whose axes are parallel to the central axis of tubular 
body 1 are provided at the end of the tubular body 1 opposite the end to 
which is attached pipe member 12. If desired, the bottoms of these holes 
may be vented to the surrounding environment by radial ports 21. 
The annular seal assembly 2 is carried by the body 1 within the counterbore 
15 between annular shoulder 16 and the seal load ring 4. The seal assembly 
2 may comprise a plurality of elastomeric annular seal rings 22 and a 
lantern ring 23. In the relaxed position shown in FIG. 1, the end of pipe 
member 13 is freely recewvable therein. However, if an axial force is 
applied to the seal assembly 2 by the seal load ring 4, the seal rings 22 
are movable to a compressed position, causing the internal diameter 
thereof to contract sealingly engaging the end of the pipe member 13, as 
shown in FIG. 3. 
The seal load ring 4 comprises a cylindrical body portion 24 and a radial 
flange portion 25. The cylindrical body portion 24 is disposed between the 
seal assembly 2 and the gripping assembly 3. The flange portion 25 is 
provided with a plurality of holes 26, the axes of which are coincidental 
with the axes of threaded holes 20 in the body 1. Holes 26 are 
counterbored at 27 to receive spring washers as will be more fully 
understood hereafter. The seal load ring 4, of course, engages the seal 
assembly 2 and is axially movable relative to the body 1 for moving the 
seal assembly to the compressed position of FIG. 3, as will be more fully 
described hereafter. 
The gripping assembly 3 may comprise a plurality of slips 28 disposed about 
the end of pipe member 13 adjacent seal load ring 4. The slips are made in 
a plurality of segments, for example six segments, so as to allow movement 
from a radially expanded position (FIG. 1) in which the pipe member 13 may 
be axially received by and displaced from the body 1, to a radially 
contracted position (FIG. 3) gripping the exterior of the pipe member 13 
and preventing its axial displacement from the body 1. The inner faces of 
the slip members 28 may be provided with some type of friction means, such 
as circumferential teeth 29, for more positive engagement with the pipe 
member 13. So that the slips 28 may operate in unison, the inner faces 
thereof may also be provided with a circumferential groove in which is 
placed a wound spring 30. The diameter of the spring 30 is such as to bias 
the slip members 28 towards the expanded position. 
The outer faces of the slip members 28 are tapered. In the particular 
embodiment shown, this taper is provided by two frustoconical surfaces 31 
and 32 joined by a cylindrical surface 33. Another cylindrical surface 34 
joins the frustoconical surface 32 to the annular end surface 35 which 
bears against one end of the seal load ring 4. 
The gripper load ring 5 surrounds the gripper assembly 3 and may have a 
cylindrical exterior 36. The interior surface of the gripper load ring 5 
is tapered to correspond with the tapered outer faces of slip members 28. 
In the particular embodiment shown, these tapers are provided with 
frusto-conical surfaces 37 and 38 joined by cylindrical surface 39. Like 
the seal load ring 4, the gripper load ring 5 is also provided with a 
plurality of holes 40, the axes of which are coincidental with the axes of 
threaded body holes 20. It should easily be understood that upon axial 
movement of the gripper load ring 5 in a upward direction, as viewed in 
FIGS. 1 and 3, the slip members 28 will be moved from the expanded 
positions of FIG. 1 to the contracted positions of FIG. 3, by virtue of 
the wedging action between frusto-conical surfaces 31 and 37 and 32 and 
38. 
The seal load ring 4 and the gripper load ring 5 make up part of an 
actuating assembly for actuating the seal assembly 2 and gripper assembly 
3. The actuating assembly may also comprise a plurality of setting screws 
41 disposed, in the illustrated case, in six of the holes 40 and 26 of 
gripper load ring 5 and seal load ring 4, respectively, and threadedly 
engaging threaded holes 20 of the body member 1. Surrounding the shank of 
the setting screws 41 within the seal load ring counterbores 27 is a 
plurality, ten in the illustrated case, of Belleville spring washers 42 in 
series arrangement. Surrounding the shank of setting screw 41, between 
screw head 43 and the end of gripper load ring 5, is a plurality of 
Belleville washer springs 44 (four in the instant case) in parallel 
arrangement. 
A torque may be applied to the setting screws 41 by engagement with screw 
heads 43, causing the setting screws 41 to further engage the threaded 
holes 20. As this is done, it can be easily understood that axially 
directed forces are simultaneously applied to the seal load ring 4 and 
gripper load ring 5 via Belleville washer springs 42 and 44, respectively. 
These axial forces effect the axial movement of seal load ring 4 for 
moving the seal assembly 2 to the compressed position and axial movement 
of gripper load ring 5 for moving the gripper assembly 3 to the contracted 
position. As the setting screws 41 are torqued into further engagement 
with the threaded holes 20, the Bellville washer springs 42 are compressed 
biasing the seal load ring 4 in a direction away from gripper load ring 5. 
At the same time the Belleville washer springs 44 are compressed, biasing 
the gripper load ring 5 toward body 1. 
The actuating assembly may also comprise a plurality of seal screws 45 
(three in the instant case) capable of applying additional axial forces to 
the seal load ring 4 without applying additional axial forces to gripper 
load ring 5. The seal screws 45 are disposed in selected ones of the holes 
40 and 26 in gripper load ring 5 and seal load ring 4, respectively, for 
threaded engagement with selected ones of the threaded holes 20 in body 1. 
However, the seal screws 45 are designed slightly differently than setting 
screws 41. The major diameter of the heads 46 of the seal screws 45 is no 
greater than the major diameter of its shank so that no shoulder is 
provided at the head 46 for engaging the end of gripper load ring 5. Thus, 
no axial force can be applied to the gripper load ring 5 by the seal 
screws 45. The shank diameter of seal screw 45 is reduced near the seal 
load ring 4 to provide an annular shoulder 47 encircling the seal screw 
45. Between the annular shoulder 47 and the bottom of seal load ring 
counterbore 27 is a plurality of Belleville spring washers 48 (nine in the 
illustrated case) some in parallel and some in series. Upon turning or 
torquing of the seal screws 45 by engagement with their heads 46, an 
additional axial force may be applied to the seal load ring 4, via 
Belleville spring washers 48, placing additional compression forces on the 
seal assembly 2. As already pointed out, no additional forces are applied 
to the gripper load ring 5. As these axial forces are applied, the 
Belleville washer springs 48 are compressed biasing the seal load ring 4 
toward the seal assembly 2. 
STATEMENT OF OPERATION OF A PREFERRED EMBODIMENT 
Referring now to FIGS. 1-4, the installation and operation of the connector 
of the present invention will be described. Although the connector can be 
used in several pipe joining applications, it will be described as it 
might be used in repairing a damaged pipe riser which rises from the sea 
floor above the surface of the water for flow to a manifold system on a 
platform or the like. In such cases, the most common area of damage is in 
the splash zone near the surface of the water. For descriptive purposes, 
it will be assumed that the pipe member 13 represents a riser which has 
been cut off to remove a damaged area thereabove. The pipe member 12 
represents a pipe nipple which may be attached in any suitable manner to 
another pipe thereabove to complete the riser when connected. 
The connector would be lowered from pipe member 12 with its components in 
the positions of FIG. 1, the seal assembly 2 being relaxed and the gripper 
assembly 3 being in the expanded position. The upper end of pipe member 13 
would be received in the connector until the cut end of the pipe member or 
riser bottoms against annular shoulder 14 preventing any further movement 
of the connector in a downward connection. 
Then the setting screws 41 would be torqued or turned simultaneously 
applying axial forces to the seal assembly 2 and gripping assembly 3. As 
the load increases, the Belleville springs 42 begin to compress, allowing 
movement of the gripper load ring 5 in the direction of seal assembly 2. 
This movement results in the inner tapered surfaces of the gripper load 
ring 5 riding along the tapered outer faces of slip members 28, moving 
them into the contracted position of FIGS. 3 and 4, wedging the slip 
member 28 into a fully engaged position with the pipe member 13. 
The force transmitted through the compressed Belleville springs 42 causes 
the seal load ring 4 to move toward seal assembly 2, moving the seal 
assembly 2 to the extruded and compressed position of FIGS. 3 and 4, in 
which the elastomeric seal rings 22 sealingly engage the pipe member 13. 
The energy stored in the Belleville springs 42 serves as a reserve system 
to maintain compression on the seal assembly 2. If desired or required 
upon installation or even at a later date, further compression of the seal 
assembly 2 can be attained by torquing down on the seal screws 45. As 
already explained, this allows additional compressive force to be applied 
to the seal assembly 2 without applying additional forces to the gripper 
assembly 3. 
To release the connector, the seal screws 45 and setting screws 41 are 
merely turned in a reverse direction until the seal assembly 2 and the 
gripping assembly 3 are in the relaxed and expanded conditions, 
respectively. The expanding Belleville spring 42, 44 and 48 and the slip 
spring 30 assure that the components return to the position of FIG. 1, 
allowing the connector to be removed for recovery, reconditioning, repair 
or reuse elsewhere. 
DESCRIPTION OF AN ALTERNATIVE EMBODIMENT 
The previously described embodiment, illustrated in FIGS. 1-4, is primarily 
designed for riser-type connections. However, the connector of the present 
invention can be easily adapted for so-called "mid-line" connections, in 
which the connected pipe members are generally horizontal, such as they 
might be on the sea floor. The alternate embodiment to be described 
hereafter with reference to FIGS. 5 and 6, represent such a connector. 
Like in the first described embodiment, this embodiment also comprises a 
tubular body 51, annular seal assembly 52, gripper assembly 53, seal load 
ring 54 and gripper load ring 55. In addition, a second seal assembly 56 
may be provided. 
The tubular body 51 may be attached in any suitable manner, such as by 
welding 57, to a pipe member 58. The tubular body 51 is provided with a 
smooth bore 59 connected to a smooth larger counterbore 60 by 
frusto-conical or tapered surface 61. Externally, the body member may be 
tapered as at 62 to reduce its weight and streamline its appearance. Like 
in the previous embodiment, a plurality of radially disposed and theaded 
holes 63 whose axes are parallel to the central axis of the tubular body 
51 are provided. 
The secondary annular seal assembly 56 comprises a plurality of slip 
members 64 having generally cylindrical interfaces on which may be 
provided friction engaging teeth 65 and tapered outer faces 66 which rest 
against correspondingly tapered frusto-conical surface 61 of the body 51. 
In the initial or unset position, the slip members 64 are held in an 
expanded position by guide screws 67 threadedly engaging holes in the body 
member 51 through slots 68 provided in the slips 64. As will be more fully 
understood hereafter, the slots 68 permit limited movement of the slips 64 
along the frusto-conical surface 61 from the expanded position of FIG. 5, 
in which the end of a pipe member 69 may be freely received therein, to a 
contracted position, as shown in FIG. 6, firmly engaging the end of pipe 
member 69. 
The annular seal assembly 52 is carried by the body member 51 between the 
secondary gripping assembly 56 and the seal load ring 54. The seal 
assembly 52 may comprise a plurality of elastomeric seal rings 70, a 
lantern ring 71 and a thrust ring 72. In the relaxed position of FIG. 5, 
the end of pipe member 69 is freely receivable therein. However, if an 
axially compressing force is applied to the seal assembly 52 by the seal 
load ring 54, the seal rings 70 are movable to a compressed position, 
causing the internal diameter to sealingly engage the pipe member 69, as 
shown in FIG. 6. 
The seal load ring 54 comprises a cylindrical body portion 73 and a radial 
flange portion 74. The cylindrical body portion 73 is disposed between the 
seal assembly 52 and the primary gripping assembly 53. The flange portion 
74 is provided with a plurality of holes 75, the axes of which are 
coincidental with the axes of threaded holes 63 in the body 51. The holes 
75 are counterbored at 76 to receive spring washers 77 similar to the 
spring washers 42 of the previously described embodiment. The seal load 
ring 54 is axially movable, relative to the body 51 for moving the seal 
assembly 52 and the secondary gripping assembly 56 to the set positions of 
FIG. 6, as will be more fully described hereafter. 
The primary gripping assembly 53 may comprise a plurality of slip segments 
78 disposed about the pipe member 69 adjacent the seal load ring 54. The 
slip segments 78 are designed for movement from the radially expanded 
position of FIG. 5, in which the pipe member 69 may be freely received 
within or displaced from the body 1, to the radially contracted position 
of FIG. 6 gripping the exterior of the pipe member 69. The inner faces of 
the slip segments 78 may be provided with circumferential teeth 79 for 
positive frictional engagement with the pipe member 69. The outer faces of 
the slip segments 78 are tapered for cooperation with correspondingly 
tapered surfaces of the gripper load ring 55. In the particular embodiment 
shown, this taper is provided by two frusto-conical surfaces 80 and 81. So 
that the slips 78 may operate in unison, the inner faces thereof may be 
provided with circumferential grooves in which are placed springs 82 and 
83. The free diameter of the springs 82 and 83 are such as to bias the 
slip member 78 toward the expanded position. 
The gripper load ring 55 surrounds the gripper assembly 53 and may have a 
cylindrical exterior 84. The interior surface of the gripper load ring 54 
is provided with tapered areas 85 and 86 corresponding with the tapered 
surfaces 80 and 81 of the outer face of slip segments 78. Like the seal 
load ring 54, the gripper load ring 55 is also provided with a plurality 
of holes 87, the axes of which are coincidental with the axes of the 
threaded body holes 63. Axial movement of the gripper load ring 55, from 
the position of FIG. 5 to the position of FIG. 6, will cause the slip 
segments 78 to be moved from the expanded position of FIG. 5 to the 
contracted position of FIG. 6, by virtue of the wedging action between the 
tapered surfaces 80 and 85 and 81 and 86. 
The seal load ring 54 and the gripper load ring 55 make up part of the 
actuating assembly for actuating seal assembly 52, primary gripper 
assembly 53 and secondary gripper assembly 56. Like in the previous 
embodiment, the actuating assembly may also comprise a plurality of 
setting screws 88 threadedly engaging selected ones of the threaded holes 
63 of the body member 51. Surrounding the shank of the setting screws 88 
are the spring washers 77. The setting screws 88 may be provided with 
heads 89 for engagement to apply a torque thereto. 
STATEMENT OF OPERATION OF AN ALTERNATE EMBODIMENT 
Referring now to both FIGS. 5 and 6, the installation and operation of the 
connector, according to an alternate embodiment of th invention, will be 
described. Initially, the connector would be joined to the pipe member 58 
by such as welding at 57 or the pipe member 58 may actually be a short 
nipple for connection in any other suitable manner to a section of pipe to 
be placed in fluid communication with the other pipe member 69. 
Initially, all components would be in the unset position of FIG. 5. The end 
of pipe member 69 would be received within the connector. It is easily 
understood that since the end of pipe member 69 does not need to bear 
against a stop shoulder, the connector is capable of a certain amount of 
longitudinal adjustment thereon to fit the particular circumstances of a 
midline pipe connection. 
After the pipe 69 is in place, the setting screws 88 would be torqued or 
turned, simultaneously applying axial forces to the primary gripper 
assembly 53, the seal assembly 52 and the secondary gripper assembly 56 
(through the seal assembly 52). As the load increases, the spring washers 
77 begin to compress, allowing movement of the seal load ring 54 and the 
gripper load ring 55 in the direction of the seal assembly 52. This 
movement results in the outer tapered faces 66 of the secondary gripper 
segments 64 to move along the tapered body surface 61, causing the 
secondary gripper assembly 56 to grippingly engage the pipe member 69. At 
the same time, the seal assembly 52 is being moved to the extruded and 
compressed position of FIG. 6, in which the elastomeric seal rings 70 
sealingly engage the pipe member 69. Simultaneously, the inner tapered 
surfaces 85 and 86 of the gripper load ring 55 ride along the tapered 
outer faces 80 and 81 of slip segments 78, moving them into the contracted 
position of FIG. 6 and wedging the slip members 78 into a fully engaged 
position with the pipe member 69. 
It will be noted that in the engaged position of FIG. 6, the primary 
gripper assembly 53 engages the pipe member 69 in such a way as to prevent 
it from being pulled out of the connector while the secondary gripper 
assembly 56 engages the pipe member 69 so as to prevent further receiving 
of the pipe member 69 within the connector. Thus, the connection is 
maintained against both tensile and compressive forces to which it might 
be subjected. 
Although the alternate embodiment has not been described as having them, it 
can also be provided with separate seal screws, such as seal screws 45 of 
the embodiment of FIGS. 1-4, so that additional axial compressive forces 
may be applied to the seal assembly 52 without applying additional forces 
to the primary gripper assembly 53. Such might be desired if the seal 
assembly 52 developed a subsequent leak. 
To release the connector, the set screws 88 may be turned in a reverse 
direction until the seal assembly 52 and the gripping assemblies 53 and 56 
are in the relaxed and expanded conditions. This would permit removal of 
the pipe member 69 or of the connector for recovery, reconditioning, 
repair of reuse elsewhere. 
Conclusion 
Since the connector of the present invention is a totally mechanical one, 
it requires a minimum of manpower and equipment backup as compared with 
other apparatus, especially those used in presently employed welding 
techniques. The tool is resettable numerous times, easily removed, easily 
disassembled in the field and reusable. 
Although it is contemplated that the connector of the present invention 
will be set by diver rotation of the setting screws. It can also be set by 
replacing at least some of the setting screws with studs on which 
hydraulic tensioning devices might be used. Furthermore, even though the 
connector has been described for utilization in the repair of a damaged 
riser and in a midline connection, it can be used in other applications, 
with or without adaption. Many variations of the invention may be made by 
those skilled in the art without departing from the spirit of the 
invention. Therefore, it is intended that the scope of the invention be 
limited only by the claims which follow.