CA1079060A - Joining underwater pipelines - Google Patents

Abstract

ABSTRACT

A spool, to be inserted between two pipeline sections, is oriented so that the corresponding points on the muting spool and pipe ends define parallel lines, and such that an imaginary line segment may be extended from the center of each pipeline section end to the center of the corresponding spool end to which it is to be joined without intersecting the wall of the pipelines or the spool. Guides are then affixed to the pipeline ends and to the spool ends, which guides define planes parallel to the line of intersection between the planes of the pipeline ends (and the planes of the spool ends which are oriented identically) and to the line segments between the centers of the pipeline end and the corresponding end of the spool. The guides are arranged to extend beyond the perimeter of the pipeline ends and the spool ends in order that the guides will engage each other before the mating spool and pipeline ends have an opportunity to come in contact.
The guides on the pipeline ends are then engaged with the guides on the corresponding ends of the spool and the spool is moved into position with the guides in engagement along a line parallel to the plane of the guides.

Description

10-~9~60 The present invention relates to apparatus ior determinin~ the relative positions o~ the nearer ends of two fixed bodies. More particularly, this invention relates to apparatus ~or ascertaining the relative positions oi the ends o~ two under~ater pipelines that are to be coupled together.
It has heretofore been ~ound di~ficult to couple together pipe sections ~hich lie on the ~loor of a body of water. Often, the topography of the ocean floor, upon ~hich a pipeline is laid, causes a sectio~ o~ pipe to assume an orientation that is different from that of an ad~acent other section. A situation such as this causes the ends of the pipe sections, which are to be joined, to be misaligned.
Additional pipeline misalignment problems may be brought about when it is desired to ~oin two pipelines together which, though lying on a ~lat ocean ~loor sur~ace, do not have their centerline axes pl~ced collinearly, Further misalignment problems may be encountered ii it is desired to couple a pipeline to a storage tank or the like. The pipeline axis at the storage tank opening might be oblique thereto, rather than perpendicular, presenting yet another type of misalignment problem.
Yarious devices have been used to effect the coupling of underwater pipeline sections. One such device is that of US Patent 3 658 231 issued to Ocean Systems, Inc. Tne -2_ . . .
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device disclosed therein includes a frame-like structure having a central chamber and movable end support -fixtures.
The ends of the pipe sections to be coupled are forced into alignment by pressure-actuated mechanisms which engage the pipe sections. Aligning pipe sections by force generally subjects the pipe sections to undesirable stresses which can cause serious damage to the pipeline.
Another device for coupling the ends o~ pipe sections is that of US Patent 3 393 926. This device utilizes a coupling into which the ends o4 the pipe sections are received.
The ends are gripped and sealed within the coupling by fluid-actuated members. This device, though adequate, is not particularly desirable since the coupling must remain on the pipeline resulting in an economic disadvantage. Also, the ends must o~ten be forced into alignment and are thus held coupled together under stress.
It is apparent that it would be desirable to be able to couple pipeline sections together by welding or bolting a connecting section oi pipe, obviating the need ~or expensive coupling devices. It is also apparent that it would be desirable to couple pipe sections without having to force the pipe sections into alignment, thereby reducing damaging stress.
Before a connecting section of pipe can be fabricated, the exact spatial relation of the planar ends of the two underwater ~ipelines must be determined. One approach in determining the relative position of two submerged pipelines is that o~ attaching pipe flanges on the ends o~ tbe pipelines '` ' '' ', ' ' ~ . .
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1079(~60 and welding several connecting rods between the flanges.
The flanges are then detached from the pipelines, and the entire structure, consisting of the flanges and the connecting rods, is brought to the surface. From the orientation of the flanges, the relative positioning of the ends of the submerged pipelines is ascertainable. Further details of this technique may be had by reference to the article "Elanged spool connects subsea pipeline ends", THE OIL AND GAS JOURNAL, February 3, 1974, pp 92, 93 and 96.
A disadvantage of this approach is that the structure of welded rods can be quite heavy, especially if the flanges are a substantial distance apart, and thus difficult to handle. Also, diver time and welding time are significant and make this technique expensive.
The present invention aims at providing apparatus which accurately measures the values of the orientation and distance parameters necessary to define the relative positioning of the adjacent but spaced-apart ends of two pipe sections.
Accordingly the present invention provides apparatus which is as claimed in the respective appended claims.
The present invention also relates to the installation of the prefabricated spool between the two underwater pipeline ends.
In making underwater tie-ins in connection with either i pipeline joinder or repair or riser flow pipe hook-ups, it is necessary to proceed through four distanct phases of the overall operation. These phases are: pipeline preparation, determination of pipeline orientation, fabrication of a , .- , : .: .

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, ~079~60 connecting spool, and installation of the spool.
The phase of pipeline preparation involves preparation of the underwater pipeline ends to be joined.
Each pipeline end is cut to define a face perpendicular to the axis of the pipeline, so that the cut end defines a circle. The pipeline ends are also cut to afford enough space between the ends for the connecting spool not to include any severe bends, which could present a significant resistance to flow. Hence, in pipeline joinder operations, the ends to be joined are in planes perpendicular to the pipeline axes. However, most frequently, these planes are at an angle to one another, and the axes of the ends will not often intersect, resulting in the necessity to fabricate a spool accurately in order to effect joinder without undue stressing or manipulation of the pipeline ends.
In accordance with this invention, the joinder of the ends may be effected by moving the spool into engagement with the pipeline ends from a number of angles which range up to 180 degrees apart. Accordingly, regardless of the disposition of the pipeline ends, an angle of approach of the spool to the pipeline ends for ready insertion therebetween will often be found. It will be understood that in some instances, as when the pipeline ends are both pointed downwardly towards the sea bed, it may be necessary to excavate beneath the pipeline ends in order to insert the spool. Nonetheless, the various angles of approach which may be used make it possible to utilize an angle of entry or insertion which minimises the amount of excavation which must be undertaken.

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107~fi(3 In accordance with this invention, there are also provided guide structures which may be used in the method o~ this invention. These guide surfaces extending beyond the perimeter of both the pipeline ends and the spool to be inserted. When properly oriented, these guide surfaces may be engaged and thereby permit the spool to be inserted between the pipeline ends with a minimum oi possibility oi damage to the pipeline ends or ~langes occurring.
It is pointed out that the method of this invention may be used to insert a spool having flan6es which are to be bolted to corresponding flanges on the pipeline ends.
Alternatively, the instant invention may be used to position a spool without a flange ~or a welded connection between two pipeline sections. In the latter instance, when the spool is to be welded to the pipeline sections, the apparatus o~ this invention may be employed to position the spool properly between the pipeline ends, A suitable welding clamp, such as is known in the art, would then be af~ixed to the spool and the pipeline end in order to hold the two members in fixed position in order to accomplish the welding operation.
In a final aspect, the instant invention includes a novel ~lange structure which includes a movable sealing ring and which may be employed on the spool or on the pipeline ends in accordance with the method o~ this invention, The novel ~lan~e structure permits a spool to be inserted between pipelir.e ends with a very close tolerance~ Aiter the flange is in position, ~ sealing ring may be moved to seal the ~unction be'cween the spool and the pipeline end.

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7g~)~0 Finally, it will be appreciated that the instant invention is particularly directed to the ~oinder o~
pipeline ends under water. Although it will be understood that the methods o~ this invention may ~e used to ~oin pipeline ends in other environments, it is in the insertion o~ a spool between two ends of an underwater pipeline that problems most often accrue. It is impractical to fabricate the spool section-by-section from one pipeline end to the other. ~ence, it 1s necessary to fabricate a spool on the suriace and insert it between the pipeline ends with a minimum oi stress being imposed on the pipeline. In surface operations, it is usually satisfactory to fabricate the spool section-by-section from the pipeline end to the other.
In accordance with this invention, there is provided a method for installing a spool between the ends of two pipeline sections as claimed in the appended respecti~e claims. As has been pointed out above, in the preparation phase of any joinder operation, the pipeline section ends should be disposed so that the centers of the pipeline ends to be ~oined may be connected by an imaginary ]ine segment which does not intersect the wall Or either pipeline section, Thus, if this condition does not exist, in the preparation phase o~ any joinder operation, one pipeline section is prelerably cut in order to achieve this condition, It is pre~erred to make the ~oinder of the pipeline sections in a fashion so ~hat there are no severe bends in :- . - . - . : .

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~79060 the spool which might impede flow through the pipeline.
Accordingly, if two pipeline sections are disposed in a manner as to create a severe angle or bend in the spool, the pipeline sections are preferably cut off. In cases where the pipeline ends to be joined are far apart, an intermediate straight section of pipe might then be inserted between two spools which inLturn connect to the free pipeline section ends. By these various techni~ues, a joinder can be effected without producing severe bends or flow obstacles in the pipeline.
It will be understood that the method of this invention may be employed to join pipeline sections of differing diameters by fabricating a spo~l which will properly mate with a different diameter pipeline section.
It will be understood that if two pipeline sections lie on the ocean bottoms with the planes of the ends of the pipeline parallel, a spool may be inserted between those pipeline sections from any angle above the pipeline In such an instance, the apparatus of the present invention could be used. However, it is in the instance where the planes of the ends of the pipeline sections to be joined lie in intersecting planes that the method of this mnvention becomes most important. Under those circumstances, it is difficult to ascertain the proper angle of entry in order to insert the spool be~ween the pipeline sections. In accordance with the methods of this invention, guides can be readily oriented on both the spool and the pipeline sections defining the direction from which insertion of the spool may be accomplished and ~urthermore, guiding ., :

, ~79~60 the spool into position with minimum damage to the ends of the pipeline sections or the ends of the spool.
Accordingly, the methods of this invention involve orienting a spool to be inserted between two pipeline sections such that the corresponding points on the mating spool and pipe ends define parallel lines, and such that an imaginary line segment may be extended from the center of each pipeline section end to the center of the corresponding spool end to which it is to be join~d without intersecting the wall of the pipelines or the spool. Thus, the spool may be oriented at any position around a 180 degree arc for insertion between the pipe sec~ion ends.
Guides are then affixed to the pipeline ends and to the spool ends, which guides define p~anes parallel to the line of intersection between the planes of the pipeline ends (and the planes of the spool ends which are oriented identically) and to the line segments between the centers of the pipeline end and the corresponding end of the spool.
The guides are arranged to extend beyond the perimeter of the pipeline ends and the spool ends in order that the guides will engage each other before the mating spool and pipeline ends have an opportunity to come in contact. The guides on the pipeline ends are then engaged with the guides on the corresponding ends of the spool and the spool is moved into position with the guides in engagement along a line parallel to the plane of the guides. By this last statement, it is meant that as the spool is moved into position between the pipeline ends, all points on the spool define lines which are parallel to the planes of the guides.

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In particular, there are two positions ~or orienting the guides on the pipeline section ends and on the ends oi the spool in order to insert the spool in accordance with the method o~ this invention. The position of the guides will be chosen depending upon the ease with which insertion may be accomplished ~rom various angles from above the pipeline ends or from the side (generally parallel to the subsea floor) with a minimum of excavation ~rom below the pipeline ends.
In one embodiment effecting the method of the invention, herein called the "parallel insertion technique", the spool ls inserted between the pipeline ends in either o~ two opposing directions along a line parallel to the line o~
intersection ol the planes of the pipeline ends. In this condition, the guides are arranged to extend beyond the pipeline on planes parallel to the pipeline faces and the spool iaces, and in a direction parallel to the line of intersection between the planes. When the spool is oriented relative to the pipeline, an imaginary line from the center o~ each pipeline end to the center of the mating spool end will exist substantially within the plane o~ the face o~ the pipeline (but not intersecting the wall of the pipeline or the spool). The ~uides are then engaged and the spool is moved into place with both spool ends moving generally parallel to the pipeline ends until the spool is in position and ~oinder may be accomplished.
ln accordance w~th an alternative embodiment o~ the method, the spool is introduced between the p~peline enAs in - ' .. . . ' - . :

1079~)60 a direction which is not parallel to the line of intersection formed by the intersectlon o~ the planes of the pipeline ends.
By introducing the spool irom æ direction perpendicular to the line of intersection between the planes of the pipeline faces, an angle of insertion 90 degrees ~rom the direction of insertion using the ~arallel technique is achieved. This method is referred to herein as the "wedge techniaue"
since most frequently when using this method, the pipeline ends and spool ends enga~e simultaneously as the spool approaches the pipeline ends from a general direction within the angle defined by the planes of the faces. Use of the term wedge technique is not intended to infer that there is deleterious wedging or binding when this method is used; the term is used because in this method, movement of the spool relative to the pipeline faces might appear to correspond to a wedge being positioned.
The wedge technique utilizes guides extending beyond the perimeter of the pipeline sections and spool, all of which are parallel, as the spool is positioned. The guides are arranged not typically parallel to the ~aces of the pipeline æection end faces or the ends oi the spools, but at an angle thereto. The guides on both pipeline section ends are disposed parallel to one another and ~orm angles with the planes oi the pipeline section end faces, the sum of which angles is equal to the angle of intersection between the planes of the ~aces, (Hence one o~ said ~uides may be parallel to the plane oi the guide face describing an angle of 0, in which case the guide on the other pipeline section would be equal to the angle between the planes of the eace~,) The guides on the ends of the .
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1~79060 spool are similarly arranged parallel to each other at angles to the spool faces the sum of which is equal to the angle of intersection between the planes of the spool faces.
The guides on the spool are disposed equidistant with the guides on the pipeline ends. This may be readily achieved by simply providing that the guide planes on each pass an equal distance from the center of the faces of the guides and spools.
In accordance with another aspect of this invention, there are provided mechanical guides for guiding pipe sections into alignment and which may be affixed to the spool and pipeline section ends. The guides comprise a removable collar which may be affixed to the pipeline end or spool end and a removable planar guide surface which is affixed to the collar. The guides are preferably removably attached to the collar to enable use of guides having varying angular orientations. Accordingly, guide -planes having the precise angular orientation with respect to the pipeline section end or the spool end necessary to achieve the desired angle to insertion of the spool may be placed on the collar for each joinder operation. The guide surfaces preferably further include tracks which enable the guide surfaces of the pipeline end guide and the guide of the mating spool end to engage, defining a linear track along which the spool may be slid to ahieve precise positioning between the pipeline ends.
In another aspe~t, the invention includes ~ sealing flange which may be desirably used in joinder operations in 1~79~60 accorclance ~ith IhiS invention. Using the methods and apparatus of this invention, it ls possible to construct a spool which will ~it within very close tolerances within t~vo pipeline ends Operating with these tolerances, it would ordinarily be necessary, when seeking to bolt the spool to the pipeline section using flanges, to effect a linear Junctionbetween the planar faces o~ the fla~ge o~
the pipeline section end and the flange of a mating spool.
~owever, for a permanent leakproof seal, it is desirable to utilize flanges having an intermediate ring movable I over the joint between the flanges to prevent extrusion or cold ~low of a gasket which is customarily employed and provide a secondary seal, In accordance with this invention, there is provided a novel ~lange construction including mating flange members having planar faces and each having a circum~erential groove in the rim surface of the flange, the said grooves being arranged to overlie each other when the flanges are joined A movable sealing ring is provided in one o~
said grooves, the ring being recessed within the groove so as not to extend beyond the planar iace oi the flange.
~eans are provided to move the sealing ring out of the groove in which it is recessed when the flan~es are in engagement, and partially into the groove oi the mating flange, thus providing a circumferential seal substan~ially perpendicular to the plane oi the ~olnt between ~langes, Pre~erably, means are provided to introduce a iluid pressure between the sealing ring and the flange in vhich .

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it is recessed to move the ring from a recessed position to a position extending into the groove of the mating flange. A hardenable material may then be introduced into the volume which was pressurised in order to maintain the sealing ring position. Thus, a gasket within the ring is prevented from being extruded and an additional seal is provided. In addition, the movable ring assists in centering the flanges relative on one another.
In accordance with other aspects of this invention, there are provided devices for handling a spool in a subsea environment to facilitate the insertion prodecure between two pipe section ends. For example, an alignment frame device is provided which effects the movement of the pipe in any direction during insertion. A suspension clamp for the spool which enables longitudinally and rotationally balancing the spool for easy diver manipulation is also provided.
The present invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure lA is a schematic diagram of two pipe sections which are desired to be joined together and illustrates the necessary parameters for defining the exact relative position of the pipelines.
Figure lB is a schematic diagram of a pipeline end misalignment situation with the geometric parameters necessary to model a connecting spool on a computer indicated thereon.
Figure 2 is an axial cross-sectional view of one apparatus of the present invention, showing typical gimbal assemblies in place on the ends of two pipe sections, - -~ -' ' : ' ' ' ' 1079~60 with a typical telescoping section extending between them;
Figure 3 is a plan view of one form of mechanism for metering the angular displacement between the reference axes of the gimb.al assemblies shown in Figure 2;
Figure 4 is an enlarged sectional view, along line 4-4 of Figure 2 of a template mounted on the end of a section of pipe and carrying a gimbal assembly;
Figure 5a is a side view of a work bench on board a service vessel, which work bench is utilised in the fabrication of a connecting section;
Figure 5b is a plan view of the work bench shown in Figure 5;
Figure 6, which appears on the same sheet as Figure lb, is a side view of an end segment of a spool that is to be fabricated to interconnect the pipe ends shown in Fig. lB, which end segment is to be attached to the end that lies in plane Pl.
Figures 7a and 7b are plan views of two pipeline sections, with Figure 7a illustrating a desirable disposition of the pipes for interconnection by a spool, and Figure 7b illustrating an un-acceptable relative positioning for connection by a spool;
Figure 8 is a geometrical diagram representing the ends of two pipe sections that are desired to be connected together by a spool, wherein the pipe ends are represented by circles Sl and S2, that lie in intersecting planes Pl and P2;
Figure 9 is a side view of a spool and two pipeline sections having mating guides secured on their ends for properly orienting the spool for insertion between the ends of the pipeline sections;
Figure 9a is a cross-sectional view of a single connection point suspension mechanism for use in positioning the spool;
~ Figure 10 is a side view of a mechanical guide piece : -15-- , . :.

: . .. , . ~ -- .. :~ : , - . , 1879~60 for attachment to the end of a pipeline section to which a spool is to be connected;
Figure 11 is a plan view of the mechanical guide piece of Figure 10;
Figure 12 is a view from the rear of the mechanical guide piece of Figure 10 and 11;
Figure 13, which appears on the same sheet as Figures 7a and 7b, is a perspective view of a spool, having mechanical guide pieces, that is inserted between the ends of two pipe sections which have mechanical guide pieces that mate with those on the spool;
Figures 14 and 15 are plan and cross-sectional views, respectively, of the mechanical guide piece in use on the pipe ends shown in Figure 13. In Figure 15 there is also illustrated a flange design having a movable sealing ring;
Figure 16 is a perspective view of an alignment apparatus for assisting in the positioning of the spool, and Figure 17 is a side view and partial cross-section of an alternate suspension apparatus to that of Figure 9a for suspending the spool at two points.
Referring to Figure la, there is shown a first pipe line section 10 ending in a flange 12, and a second pipeline section 14 having a flange 16. Pipelines section 10 and 14 are shown to have a relative orientation in which the center-lines of each are non-collinear. Represented schematically are two coordinate systems at the ends of pipelines 10 and 14.
The coordinate system associated with the end of pipeline section 10 defines two angle parameters, p and t , - ' . ' ' , - .

iO79~)60 which represent the angular position of a line segment Ll rotated separately about the X and Z axes, respectively, of the coordinate system of pipeline section 10. The angle P
is measured between the X-Y plane and line segment Ll or alternatively with respect to the Z axis. The angle t is measured between a projection of line segment Ll onto the X-Y plane and the Y axis.
A second coordinate system having first and second coordinate axes, X' and Z', is formed at the end of pipeline section 14. The second coordinate system lies coplanar with the flange 16 attached to the end of pipeline section 14 with the spatial orientation of pipeline section 14 being represented by the parameters p' and t'. As with the parameters p and t of the first coordinate system, the parameters p' and t' represent the angular rotation of line segment Ll about the two coordinate axes defined at the end of pipeline section 14.
The angles p' and t' are measured in a manner similar to the angles p and t. All the angle parameters are measured from an initial position wherein line segment Ll is perpendicular to the X-Z plane of the coordinate systems.
Line segment Ll spans the distance between the origins of the two coordinate systems. The origins of each axis provide indexing points from which the lineal distance between the center of the planar ends 12 and 16 can be determined. In addition, provision must be made for a determination of the circular positioning of the pipeline sections 10 and 14 relative to one another based upon the angular displacement between the chosen reference axes of each coordinate system as projected onto a plane perpendicular to line Ll. This parameter is represented by g.

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10'790~;() It will be apparent from the representation given in Figure la that six parameter variables are utilized to represent the relative positioning of pipeline sections 10 and 14. With the values of the various parameters known, it is then possible to construct a coupling section to fit between the two pipe line sections, placing them in communication with one another.
Referring to Figure 2, there is shown a cross-sectional view of the preferred embodiment of an apparatus for implementing the concepts of the present invention.
Specifically, gimbal assemblies 20 and 22 are shown attached to flanges 12 and 16 by templates 24 and 26. Template 24 is secured to flange 12 by bolts 28, 29 and 30 (not shown), and template 26 is secured to flange 16 by bolts 32, 33 and 34 (not shown). The positioning of templates 24 and 26 on flanges 12 and 16 is made with reference to alignment notches 13 and 15 (Figure la) on the edges of flange 12 and flange 16, respectively, with the axes Z and Z' being aligned with the notches.
Gimbal assembly 20 includes a gimbal housing 36 which is secured to template 24 by screws 37 and carries a gimbal yoke 38 having upper and lower spindles 40 and 42.
Lower spindle 42 is journaled in a bearing 44 formed in gimbal housing 36, and upper spindle 40 is received into a portion of gimble housing 36 where it is operably connected to electrical sensing means 46. Electrical sensing means 46 can be a variable impedance device which is to be directly . . . - : . . - ~ . - : -, ~ . , , , , ~ :
- . . . - . .. , :
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1~79060 read for the value thereof, or it can form a portion of the frequency determination network in a variable frequency oscillator. Electrical sensing means 46 serves to translate the t parameter of gimbal 20 into a representative electrical quantity, i.e. impedance value of frequency.
The horizontal coordinate axis, X, of gimbal assembly 20 is defined by axle 48 which is carried in gimbal yoke 38.
Attached to axle 48 is a second electrical sensing means 50 translating the p parameter of gimbal 20, which electrical sensing means 50 is mounted in a body portion 51 having an extension 52 that forms an indexing point on gimbal assembly 20. In the preferred embodiment shown, electrical sensing means 50 is a variable impedance device which, as pointed out previously with regard to electrical sensign means 46, could be used in counjunction with a variable frequency oscillator.
Electrical connections from both elect~ical sensing means 46 and 50 can be by conductor pairs 45 and 49 which connect to a plug receptacle 53 mounted on template 24. Plug receptacle 53 would be color-coded or marked in some way to identify that it is associated with gimbal 20, or it could be a one-way plug having a unique pin connection layout.
Gimbal assembly 22 is identical to gimbal assembly 20, and inc~udes a gimbal housing 54, connecting to template--26 by screws 55, and a gimbal yoke 56 having upper and lower spindles 58 and 60, Electrical sensing means 62 , translating the t' parameter, is mounted within gimbal housing 54 and receives upper spindle 58. A second coordinate axis is defined by axls 64 carried in gimbal yoke 56 having ' :' -' - ~ ,' ' -~079~60 electrical sensing means 66 mounted thereon to translate the parameter _' into a representative electrical quantity.
Electrical connections to electrical sensing means 62 and 66 are made by conductor pairs 61 and 65, respectively, which connect to plug receptacle 67 mounted on template 26.
Plug receptacle 67 is color-coded or marked to be differentiable from plug receptacle 53.
Connecting member 18 is shown to be telescopic and extends between gimbal assemblies 20 and 22 at the centers thereof. Member 18 thus interconnects indexing points at the origin of the coordinate axis system defined by the positioning of the gimbal assemblies relative to notches 13 and 15. Connecting member 18 has an outer tubular portion 68 which fits onto extension 52 and is held in place thereon by a pin 70, and also includes an inner portion 72 which slides freely within the outer tubular portion 68. The inner sliding portion 72 has a groove 74 formed over a portion of its length through which guide pin 76, carried by the tubular portion 68, slides freely. End 78 of inner portion 72 has connected to it a string 80 which connects to electrical sensing means 82 shown to be mounted inside extension 52 and also connecting to plug receptacle 53. String 80 operates a take-up spool (not shown) which is mechanically coupled to electrical sensing means 82 such that a change in the length of connecting member 18, produced by the sliding of inner portion 72 within tubular portion 68, will be translated by -the electrical sensing means 82 into a representative electrical quantity. If necessary several additional segments can be added to inner portion 72 to extend its length so long as , . , , : -- . ~ -.
'- : '' ' , .':' ,' '~ ' :' ' ' ~ ' , - ' 1~79~)60 proper referencing to the notch 13 on flange 12 is observed.
The opposite end of inner portion 72 carries a pin 84, which along with the end 86 of inner portion 72~is received into a sleeve portion 88. Pin 84 is aligned with pin 70 and is consequently aligned with notch 13 on flange 12.
Sleeve portion 88 fits onto extension 92, which forms an indexing point on gimbal assembly 22, and has a longitudinal slot 89 for receiving pin 84. Electrical sensing means 90 is mounted on extension 92 and is mechanically coupled to :-sleeve 88 such that rotational movement of sleeve 88 relative to extension 92 will be sensed by eledtrical sensing means 90 which is connected by wires 61 to plug receptacle 67.
Member 18 is securely attached to gimbal assemblies 20 and 22 at its ends 17 and 19, respectively, and is extensible or retractable to permit variations in length, with inner portion 72 freely sliding within tubular portion 68 guided by guide pin 76 and groove 74. Preferably the overall buoyancy of member 18, when immersed ~n water, is neutral or only slightly negative to assure against bending and consequent erroneous readings. Rotational movement of inner portion 72 relative to tubular portion 68 is prevented by the arrangement of guide pin 76 and groove 74, but sleeve portion 88 is designed for limited rotational movement -: ~ -re~tive to inner portion 72 and the remainder of connecting member 18. A more detailed understanding of this arrangement -~
may be gained from Figure 3.
As may be seen in Figure 3, slot 98 extends over a portion of the circumference of sleeve portion 88, with pin 96 extending upwardly from extension 92 into slot 98.

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1~79~6~ --Sleeve portion 88 is permitted to turn about extension 92 until pin 96 stops the movPment. As sleeve portion 88 is rotated, electrical sensing means 90, which is mechanically coupled to sleeve portion 8~, translates sleeve position (the parameter g) into a representati~e electrical quantity.
If the reierence axes of gimbal assemblies 20 and 22 are not in circular alignment, that is, the "roll" o~ one pipeline is different from the other, sleeve 88 must be rotated in order for pin 84 to slide into the slot 8g. The amount o~ rotation required is sensed by electrical sensing means 90 to indicate the circular displacement between the reference axes of girnbals 20 and 22.
Shown in phantom in Figure 2 is a container 120 which houses an oscillator for supplying an electrical signal to the service ship, which si~nal is oi a defined frequency.
A multi-wire cable 122 extends between container 120 and the service æhip, with the wires therein supplying power to the oscillator, providing conductoræ for the output si~nal of the oscillator, and carrying control signals to a stepping relay. Cables 124 and 126 connect container 120 with plug - receptacles 53 and 67 respectively. A stepping relay sequentially connects each electrical sensin~ means 46, 50, 82, 6a, 66, and 30 to the oscillator in container 120.
In the pre~erred embodiment, the electrical sensin~
means are variable impedance potentiometers. The potentiometers nre utilized as a component in the frequency determining portion o the oscillator and thus, the oscillator output -22_ . : . , ' ~

11)79060 will be a signal of a frequency which is dependent upon the impedance value of the particular potentiometer connected to it at any one time. The impedance values of electrical sensing means 46, 50, 62 and 66 are, of course, determined by the position of the extensions 52 and 92, which are indexing lugs for measuring the angular displacement between notch 13~and notch lS (i.e. angle g) with respect to the plane of the ends of the pipelines, and the impedance values of electrical sensing means 82 and 90 are determined by the distance and angular displacement between the gimbal assemblies 20, 22. Therefore, by taking a reading of the frequency of the oscillator output signal as each potentiometer is separately connected to the oscillator, the values of the various parameters necessary for the determination of the spatial orientation of the pipelines will be known.
Referring now to Figure 4, there is shown a front view of the flange portion 12 of pipeline section 10, having mounted thereon template 24 and gimbal assembly 20. In -this view, template 24 is shown to be a triangular plate-like member connecting to flange 12 by bolts 28, 29 and 30.
Alignment notch 25 in template 24 services to designate the axis formed by upper and lower spindles 40 and 42 as the reference axis for the coordinate system. For proper reference alignment of the gimbal assembly 20, the flange - -12 is marked in the same manner by notch 13 to designate the positioning of notch 25 of template 24 relative to the flange 12. ~-In this view, gimbal yoke 38 is shown to be a ~.

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1~7~060 rectangularly-shaped piece having segment 47 of axle 48 is secured firmly therein, with electrical sensing means 50 mounted hereon with a portion 100 secured firmly to axle segment 47. Another segment 49 of axle 48 rotates in gimbal yoke 38 with another portion 102 of electrical sensing means 50 fixed thereon. Body portion 51 is fixed to the portion 102 of electrical sensing means 50 and encloses it.
The gimbal assembly 20, as shown, provides pivotal movement about the Z axis defined by upper and lower spindles 40 and 42 and further provides pivotal movement about the X axis defined by axle 48. As stated previously, gimbal assembly 22 is identical in construction to gimbal 20 : :
and provides the same pivotal movement.
Referring to Figures 2 and 4, to provide back-up protection in case of a failure of the electrical sensing means or a break in the conductors attached to them, locking mechanisms are provided for all movable, parameter-registering, portions of the apparatus. For example, pin 76 is screw-threaded and screws through outer portion 68 of connecting member 18 and into contact with the bottom of groove 74 in inner portion 72. Pin 76 is provided with a crank arm 77 which permits a driver to screw pin 76 tightly against inner portion 72, thereby fixing the position of the inner portion 72 and preserving its location. Also, a lock-down 108, formed of a screw-threaded bolt and a clamp member, provides means for fixing the position of sleeve 88, and thereby preserving the value of the circular displacement parameter ~. Inner portion 72 could be marked with a length scale thereon to provide a direct reading therefrom ~079~60 of the length o~ connecting member 18, and plate lll (to which sleeve 88 is clamped against by lock-down 108) Gould have a c~rcular displacement dial or similar vernier dial marked thereon to provide a direct readin~ there~rom of the circular displacement between gimbal reference axes.
In addition, the gimbals 20 and 22 have lock-down mechanisms to permit the angular displacement of the ends of connecting member 18, as registered by its rotation about the coordinate axes, to be preserved.
Speci~ically, gimbal 20 is provided with lock-down 114 (Figure 2) which serves to clamp the head 41 of upper spindle 40 and prevent movement thèreof, and similarly, ~- -~imbal 22 is provided ~ith a lock-down 116 which clamps the head 59 of upper spindle 58. Lock-downs 1l4 and 116 are identical in construction to lock-down 108 previously deficribed in detail above.
With reference to Figure 4, another lock-down 118 for gimbal 20 is shown mounted on gimbal yoke 38 to ~ix the position oi segment 49 of axle 48, Lock-down 118 preserves the value o~ the ~ parameter ior pipeline 10, ! a~d is identical in construction to the other lock-down devices. As with connecting member 18, gimbals 20 and 22 could have a scale marked thereon to permit direct readings oi the parameters, Once the ~ock-down devices are tightened to secure the positions oi the gimbals 20, 22 and connectin~ member l~, . . .. ~ . - '' .
-, ~: ;

~079()60 the apparatus may be sufficiently dismantled, withoutdisturbing the lock-down devices, to permit it to be removed from the submerged pipelines and brought to the surface. The apparatus can be broken down into two portions by removing inner portion 72 from sleeve 88, to permit easier handling of the apparatus, without losing the circular displacement reading because sleeve 88 is held by lock-down 108. - -Referring now to Figure 5a, there is shown equipment which is utilised for the fabrication of the connecting section of pipe for the misaligned submerged pipeline ends.
Work bench 130 includes a gimbal assembly 132 mounted on an elevated portion 133, which gimbal assembly 132 is supported by a mounting support 134. Also shown is a trolley 136 which supports a second gimbal assembly 138. The gimbal assemblies 132 and 138 simulate the spatial orientation of the ends of the submerged pipelines.
Gimbal assemblies 132 and 138 are very similar to gimbal assemblies 20 and 22. Specifically, gimbal assembly 132 includes an inner ring 140 that is pivotally attached to an extension 142 by a clevis-like arrangement 144. In addition, an outer ring 146 receives upper and lower spindles - -148 and 150 that are mounted on ring 140. Guter ring 146 includes bearin8 surfaces in which the upper and lower spindles are journaled. A flange connection 152 is attached to outer ring 146 and extends entirely around the gimbal assembly 132. The flange 152 provides a point of attachment for the flange of the connecting section that is to be :

. . : -- ~

fabricated.
Gimbal assembly 138 is similar to gimbal assembly 132, and therefore, the details of gimbal assembly 138 will not be described. Gimbal assembly 138 is mounted on the trolley 136 which is able to be moved forwards and backwards and to be loced in position. Also, trolley 136 is placed on work bench 130 such that the extensions 142 and 154 are aligned. A lock-down clamp 156 is provided which permits trolley 136 to be firmly held in position once it is positioned to establish the proper distance relationship between gimbals 132, 138.
Gimbal assembly 138 is provided yet further with circular movement to permit the simulation of the circular displacement between the reference axes of the gimbal assemblies 20 and 22. This movement is provided by a rotatable fitting 158 that connects extension 154 to a mount 160 on trolley 136.
Both gimbal assembly 132 and gimbal assembly 138 have verniers to permit accurate settings of the orientation of flange connections 152 and 162. Also, the gimbal assemblies 132 and 138 have lock-down devices (not shown) which fix the gimbals in the desired position that simulates the arrangement of the submerged pipeline ends.
Figure 5b is a plan view of the equipment shown in Figure 5a. In addition, there is shown a connecting pipe section 164 shown in place on work bench 130 and which is under fabrication. The flanges 166 and 168 are held onto flange connections 152 and 162 so as to place the front 1~79060 edge of the flanges in line with the center lines of the gimbal assemblies~
In operation, the apparatus of the present invention will be carried by divers to the submerged location of the pipeline sections with the connecting member 18 attached to gimbal assemblies 20 and 22 or carried separately with attachment being made on location. Upon reaching the location, the divers will mount assemblies 20 and 22 to the ends of the pipeline sections at the proper location on the pipeline section flanges to align the reference axes, Z and Z~, with the notches 13 and 15.
If the two pipeline sections are misaligned, the connecting member 18 will not be perpendicular to the coordinate axis systems defined by gimbal assemblies 20 and 22, but will assume some other orientation in space, depending upon the relative positioning of the pipeline sections. Figure la illustrates one example of misalignment between pipeline sections and the corresponding attitude that connecting member 18 will assume. As is evident from the schematic diagram of Figure 1, connecting member 18 pivots about the Z~ axis, to a position wherein it defines an angle t' with the X~ axis, and pivots about the X~ axis, defining an angle p~ with the Z~ axis. Similarly, connecting member 18, in assuming the orientation shown, pivots about the Z axis and defines an angle t with the X axis, and also pivots about the X axis and defines an angle p.
The various electrical sensing means which translate these parameters into representative electrical quantities are connected via conductors to an oscillator which will , ' ~ : : . '. :

1~79060 generate an electrical signal having a periodic waveform that is determined by the electrical sensing means. Readings for the parameters, i.e. the distance L between the two pipeline sections, the angular displacement between the reference axes of the two gimbal assemblies, and the pitch and yaw parameters p~ p~, t and t~, can be made sequentially, with the frequency values being displayed on a read-out device or fed into a remote computer for processing. It would also be feasible to have the oscillator output signal modulate a carrier signal to provide radio wave transmission of the parameter readings to a location a great distance away from the submerged pipeline location, for example, to a location on shore rather that a vessel promimate the pipeline.
With the values of the six variables known, the exact relative positions of two pipeline ends can be ascertained.
Accordingly, the positions of the ends can be simulated on board a ship or on shore to provide a template or jig by means of which a connecting pipe section, having the proper dimensions and form shown in dotted outline at 164, can be fabricated~
lowered to the underwater location, and installed between the two misaligned pipe sections. Preferably~ since circular flanges are most typically available, the connecting section is fabricated using circular flanges at each end. Curved rather than straight sections may be used.
An alternative approach to the fabrication of an inter-connecting spool is that of utilizing the parameter measure-ments obtained from the remotely read electrical signals from the various electrical sensing means to formulate a -: :

~ ~)79060 design of the spool on a computer. With a computer, a spool can be completely defined before it is built by simulating the spool on the computer in the form of a mathmatical model.
In computer slmulation, the mathmatical equations and data needed to design a spool are stored in a computer. The necessary data will normally be the values of the parameters which define the spatial relationship of the pipeline ends and any limitations that are to be placed on the spool design, such as minimum angles of intersection between adjacent spool sections. The spool designer~ using a type-writer-like terminal or a visual display unit to communicate with the computer, can vary the configuration of the spool until a design is achieved that will be an exact intercon-necting fit between the misaligned pipe ends. After the overall spool is designed, a print out of the exact specifi-cations of the spool sections can be obtained from which workers can fabricate the actual spool.
In order to perform computer simulation as generally described above to design a spool configuration for inter-connecting two pipeline ends, the exact spatial relationship of the pipeline ends must be known. The apparatus herein described provides information in the form of the six para-meters t~ t', p, p~, g and L (see FIG. lA) which are ade- -quate to completely describe the spatial relationship of the pipeline ends. These parameters are, of course, determined with respect to the Cartesian coordinate axis systems formed at each of the pipeline ends. These two coordinate axis systems (X, Y, Z; and X~ Y~ Z~) are further illustrated in FIG. lB which shows each system in a plane Pl, P2, each being a plane of a face of a pipe end.

.- -. . ~ ~ .

1079~60 .

Before proceeding with ~he development of the equations necessary for computer simulation and determination of an interconnecting spools, the parameters being measured are summarized as follows:

t = rotation of connecting member 18 about the Z axis of the coordinate axis system of pipe end 10.

p, = rotation of connecting member 18 about the X axis of the coordinate axis system of pipe end 10.

.
t' = rotation of connecting member 18 about the Z' axis of the coordinate axis system of pipe end 14.
.~ ' . ' .p' = rotation of connecting member 18 about the X' axis of the coordinate axis system of pipe 14.
. `.

g = rotation of outer sleeve 88 about inner sleeve 72.
,' ` , ' ' ..
Ll - the center-to-center distance between the origins of the coordinate axis systems at the ends of pipes 10 and 14.
. ~ -In the following equations, ~ = t' .

.. . . .
.

' .

By utilizincJ a movable set of Cartesian axes, whi.ch are initially coincident -~ith the coordinate axes in plane Pl and undergo a sequence of successive rotations with respect to the fixed origin O in the plane Pl, transformation equa-tions can be written to relate the coordinate axis systems of planes Pl and P2. The result of using a movable set of axes rotated about the origin O is that a set of coordinate axes may be defined which will be parallel to the coordinate axis system in plane P2.
For rotation of the movable axes about the Zl axis through .an angle t, the resulting X1, Yl, Z1 axes are re-lated to the X, Y, Z axes by the transformation equation:
X = P X
where the symbol X is used for the column vector (Y) and the rotation matrix F is cos t sin t o~
. F = -sin t cos t O
~ ' . ' . ' O ,0 1 For rotation of the movable axes about the X1 axes through an angle p, the resulting X2, Y21 Z2 axes are given by the transformation X = E- X
where . . f _' . 1 0 0 E = O cos ~ sin P

O -sin P cos p ~ .

- . :, - . .

-, , ~ . ' , ., - . . .

1~'79(~60 ~ he results of these two rotat:~ons applied in the order specified gives a set Or axes (X2, Y2~ Z2) which are oriented such that the Y2 axis is the longitudinal axis of the line L
between O and 0'.
Applying the transformations successively gives

2 E Xl = E F X = M X, where . ~cos t sin t O
M = E F = I cos p sin t cos p cos t sin sin P~sin t -sin P cos t sin p . ' ''' .
.. The direction cosines of the line Ll relative to the X, Y, Z axes are given by the elements in the second row of matrix M as:

. lo = -cos p sin t mO = cos p cos t nO = -sin P cos t . ,' .
Rotation of the movable axes about the Y2 axis through an angle g gives a set of axes X3, Y3, Z3. The transform equation is X3 = D X2, where ' ' - .

~cos ~ O -sin e ~ -D = O 1 O
. . sin g . ~ cos g .
` : ' .

:L079060 Rotation of tlle movable axes about the X3 axis through an angle p' yields another set of axes (X4, Y4, %4) which are related to the (X3, Y3, Z3) axes by the transformatio~
. X4 = C X
where ~1 0 0 C = Ocos P' sin P' . O-sin ~' cosP' Rotation of the movable axes about the Z4 axis through . .
an angle ~' yields a (X5, Y5, Z5) coordinate axis system given by the transformation where ~ cos ~' sin ~' O~
B = -sin ~' cos ~' O ¦ : :
O ' O 1/

After all of the above rotations are applied, a set of axes (X5, Y5, Z5) is obtained, which axes are parallel to the X', Y', Z' axes in plane P2. Successive application of the transformation gives .

4 B C X3 = b c D X2 B C D M X = A X, ' where matrix A = R C D M having the elements of:

_34_.

, - .-. .: ~. . - - -.
. . . . .

1~790~0 all = (cos ~ cos g ~ sin ~ sin p~ sin g)cos t -sin ~ cos p~ cos p sin t +
(- cos ~ sin g ~ sin ~ sin p' cos g) sin p sin t al2 = (cos ~ cos g + sin ~ sin p' sin g)sin t +
sin ~ cos p' cos p cos t -(-cos ~ sin ~ + sin ~ sin t' cos g) sin p cos t ~, al3 = sin ~ cos P' sin p +
(- cos ~ sin g + sin ~ sin p' cos g)cos p a21 = ~-sin ~ cos g + cos ~ sin P' sin ~)cos,t -cos ~ cos p' cos p sin t +
(sin ~ sin g + cos ~ sin p' cos g) sin p sin t .
a22 = (-sin ~ cos g + cos ~ sin p' sin g) sin t +
cos ~ cos p' cos p' cos t -(sin ~ sin g + cos ~ sin p' cos g)sin ~ cos t a23 = cos ~ cos p' sin p +
~ (sin ~ sin g + cos ~ sin p' cos g)cos p ' ' a31 = cos p' sin g cos t + sin p,' cos p sin t +
cos P' cos g sin P sin t a32 = cos P' sin g sin t - sin P' cos p cos t -cos P' cos ~ sin P cos t , a33 = -sin P~ sin P + cos P' cos g cos P

, ' ., ~ :.

~ 1 ' 1079~0 .
Using the ~ran.sformation e~uations derived above and vector analysis techniques, the desired quantities in FIG. lB needed fcr modeling an interconnecting spool can be : developed in terms of the measured parameters.
'Since the X5 axis is parallel to the X' axis and the direction cosines of the X5 axis relative to the X, Y, Z
axes are the elements in row one of the A matrix, the direction cosines of the X' axis relative to the X, Y, Z
axes are .
- 11 = . all ml = al2 , Similarly, the direction cosines of the Y' axis are the . elements in row two of the A matrix and are 2 a21 m2 = a22 n2 = a23 . ,The direction cosines of the Z' axis are the elements in row three of the A matrix are .1 .

13 = a31 m3 = a32 n3 = a33 .

- , The location of the origin O' of'the X', Y', Z' coor-dinate axis s.ystem relative to the X, Y, Z system,is ex- ~' ' pressed in terms of the length of the line Ll which extends between the two coordinate axis systems and the direction cosines of the line as follows:

XO' = Ll 1 Y ' = L M O Ll No .

. ' .''- '. . . ' ' ,-' ,' ' -' ' , - ~ ~,':
, : . . -: .: . : .

10~79~60 The line of intersection I of the planes Pl and P2 is given by the simultaneous solution of the equations of the two planes Pl and P2. The equation of plane P2 in X, Y, Z
coordinates can be written as ax + by + cz + d = o where a = m3 nl - ml n3 b = n3 11 - n c 13 ml ll m3 d = -(axO + ~yO + czO-) and the equation of plane Pl in X, Y, Z coordiantes is -Thus, the equation of the intersection I of Pl and P2 in X, Y, Z coordlnates is ax + cz + d = o, y = o .
In plane Pl, the line OB is drawn through the origin O such that it is perpendicular to the line of intersection .. of the planes Pl and P2 with point B being the point of intersection of the two lines. The distance of line OB, which is expressed as L2 is given by L2 d ~-- .
. -37--.
.. . . . .

' ,:' -':' ;"' '' ' "" ' ' -. .
. .

10~79~60 The an~le ~ betwee1l the liile ~B and the positive Z axis is given by ~ = sig~ ~ ] [ ~ ~ ]

The direction cosines of the line of intersection I are given by l = -c sign (d).
2 2' m = o n = + a sign (d) Ja2 + C2 The direction cosines of the line OB are given by .

14 = -n m4 n4 = l . Finally, the coordinates of point B are ' XB = L2 14 B L2 m4 = O
ZB = L2 n4 . . '' . . .
~ -38 ~' '' ,, .

- : . ~. .- : - . - .:
- . :. . . . - . . . . ~ ..
. ' .. : ~ ' ' : - - - , .:

- .. : . - .
~. ,: . . - : . ~ , ~079060 In plane ~, he line O'C is drawn in plane P2 and is perpendicular to the line of intersection I with point C being the point of interscction. Also shown in P2 is the line O'B the len~th of which is .
. 3 (XB ~ XO') + (YB ~ yo~) + (ZB ~ Zol)2 The direction cosines 15, m5, n5 of line O'B relative to the X, Y, Z axes are = X - X ' T
. ~3 = YB Yo n5 = B O

The angle ~ between the line O'B and the line of inter-. section I is given by COS E - 15 1 + m5 m + n5 n The length L~ of line CB is given by ~ L3 ¦ cos ~ ¦

The length L5 of O'C is then obtained as ~ '' .

- I ¦
.
~39 , ' . .:. .~ . . - . `
. . . :
, . ' : : . . . :
. ., .: : --: - ~ ~ ' .. ~ , The coordinates of the point C are given by X = X - L4 1 Yc = YB L4 Zc = ZB L4 : The direction cosines of the line O'C are 1 = XC ~ Xc' m6 =Yc Yo .-, .

n6 =Zc ~ Zo ' . - .

.
The angle ~' in plane P2 ~etween the line O'C and the positive Z' axis is given by cos ~' = 13 16 + m3 m~ + n3 n6 The angle ~ in plane P2 between the line of intersec-tion I an~ the positive Z'~ axis is

3 3 3 ' .
Thus, the anyle Q' can alsG be expressed as ~, ~' = sign (cos ~) cos 1 (cos : ', - : ' '-' : ' ~: ' -. ~ . ' - ' :' : ' ' ''' ' ' ' ~';' ~' ' ' 10'79060 The an~]c ~l between plane Pl and P2 is given by cos (2~) = 14 16 + m4 m6 4 6 With the above quan~ities determinable from the equa-tions expressed in terms of the measured parameters, an interconnecting spool can be designed in component sections which can be welded together. In joining the points o' and o' by line segments, two different cases are involved, One case is that wherein the points B and C are coincident;
that is, C and B line in the same plane. In the second case and the more general situation, C and B are displaced apart some distance along the line of intersection I. Although either situation can be presented in a pipeline end mis-alignment situation, where the terrain of the ocean bottom is flat, the centers of the pipeline ends will lie close to a common plane. In the discussion which follows, it will be assumed that the centers o~ the pipeline ends are coplanar.
The angle v will be used to represent the angle through which flow must turn in going from O to O'. a will be the maximum allowable flow turning angle, and t will be the : minimum number of turns required such that no turn exceeds the angle a. Accordingly, t = v . a ~ :
For each turn required, the flow turning angle ~ is chosen to b~? the same for each turn with T being no greater than a.

Hence, .t - v .' .- '~, ~'' ' ' :.
'' 10'~'9~6Q

The numbcr (S) of spool segments re~fuired to turn the flow through v subject to the maximum turning angle limita-tion is S = 2 + t. By assignment Si as the length of a spool segment, where i is the spool se~ment identifying index, the total length Ls of the spool between o and o' can be expressed as follows:

s Ls = ~ Si i=l The length L1 between o and o' is related to the spool segment lengths Si and the angles v and T by the equation s Ll = ,~ Si co~ [ v ~ l) A further constraint is placed on the problem by re-quiring each spool segment to be of the same len~th such that Si is equal to S. The solution for S is then obtained from S = L
.

~ [ -- ( i--1 ) T] ~ .
i=l ' After solving for S for each spool segment, the segments can be made from straight pipe lengths in the following manner.
For the first segment shown in FIG. 6, which attaches to pipeline end 10 in FIG. lA (Sl in plane Pl in FIG. lB), the reference point Z; N is located. The angle ~ from Z, N
is determined and a point marked as ~ on the periphery of the pipe. An arbitrary angle ~ is measured from A and a .

107gO~O

point Fo is marked on the spool segment. From ~IG. 6, h and k can be determined as .
h - R cos p k = h tan (-T2 ) The length Fo Fl = S-k = S-R cos p tan ( ~ ). To cut the segment shown in FIG. 6 , a piece of pipe must be used that is at least S + R tan ( 2 ) in length.
The layout for the spool segment which attaches to pipe end 14 of FIG. lA (S2-in plane P2 in FIG. lB) is fabricated in the same manner as the spool segment that attaches to pipe end 10.
The procedure for determining the configuration for the intermediate spool segments follows the same procedure as the end segments of the spool. An intermediate spool section to connect the two end segments together must be at least S + 2R tan ( 2 ) in length.
The spool segments are connected together by matching the points A and N on each segment to make up the overall spool.

It will be apparent to those skilled in this art that - many modi~icati~ns and changes may be made in the apparatus described~ For ex~le, the gimbal assemblies may be provided ~ !~

-43_ i - . .. : - . . - . . .
: ~ - . - , . : ' - ' . .' ' ': - ~ "' '' ~. - :

10791:~60 with ball-and-socket joints rather than the yoke and axle arrangement shown. Also, although the foregoing description of the preferred embodiment was made with regard to pipeline sections having flanges at their ends, the present invention is not limited solely to such application, and can also be utilized effectively with pipeline sections without flanges.
In such an application, the gimbal assemblies can be mounted on plugs rather than templates, which plugs can be inserted into the ends of the pipeline sections.
Pipeline preparation is well known and applicable to all techniques in making underwater tie-ins that involve the fabrication of a connecting spool member. Principally, the major requirement is that pipeline ends must be open to one another. The sketch of Figure 7a illustrates this relationship in contrast to the undesirable situation presented in Figure 7b. Both figures are schematic plan views of pipeline sections laying on the ocean floor. The pipelines may be disposed at the same elevation, as by laying on a flat bottom, or disposed at different elevations.
Further, the pipeline sections to be connected may be tilted with respect to one another.
Briefly stated, the principal requirement of open and opposing pipeline ends is met if the ends are disposed such that the centers of the respective pipeline ends may be connected by an imaginary line which does not intersect the wall of either pipeline section. Figure 7a reflects this proposition, as the imaginary line L connects between the centerlines of the pipes 20 and 30 without having to pass through the wall of either pipe section. As a practical : ;. ` ` :

.

~79060 limitation, it is preferable that the ends of the pipeline be so disposed that the imaginary line L forms angles a and b with the planar surfaces of the pipeline ends, with the angles being greater than a certain minimum. Preferably, the angles should not be so acute as to create a bend in the pipeline which causes an inordinate amount of resistance to flow. Generally, the angles a and b will be greater than 45 degrees, though this invention may be employed to join any pipeline ends open to one another.
In addition, it is desirable that pipeline ends also be displaced a sufficient distance apart such that connecting spool will not have to have a short radius of curvature.
When a situation such as that shown in Figure 7b is presented, the principal requirement of ends open to one another is not met. As is apparent, the requirement of having an imaginary line connecting the centers of the respective pipeline ends without intersecting the wall of either pipeline section does not exist. Instead, the imaginary line L' connecting between the centres of the pipeline ends must intersect the pipeline section 30 along its length and pass through the wall thereof in order to reach the center of the end. To remedy the situation and present the desired relative positioning that is necessary to meet the requirement of open ends~
one of the pipelines could possibly be moved. The more practical approach would be to cut off the end of the pipe to a point along the pipe section, as shown in phantom in Figure 7b, such that the ends are open to one another _45-1~'79~60 and the principal requirement is met. As shown, an imaginary line L may then be drawn between the centers of the pipeline ends without intersecting the wall of either.
The modification of the pipelines to conform them to the arrangement shown in Figure 7a is broadly referred to as the llpreparation phase" of the tie-in operation and involves the principal requirement that the disposition of the ends be as discussed above. Also, preparation of the ends involves "squaring-off" the ends such that each end lies in a plane that is perpendicular to the centerline of that pipeline section.
In the case of a long distance between the ends of the pipeline sections to be connected, it is recommended that a straight intermediary spool aligned generally along a line between the ends of pipelines 220 and 230 be provided, and that two short connecting spools be used for final makeup. The straight spool would be lowered to the ocean floor with its ends closed to provide enough flotation to permit the spool to be easily set at a location intermediate the ends of the existing pipeline sections and generally along a line connecting the centers of the ends. The problem of fabricating two spools having other than a straight configuration would then remain.
The next phase of the operation is that of determining the spatial relationship of the pipeline ends so that the arrangement of the pipeline ends can be simulated by a jig contrived on a deck of the support 1~'79060 ship. Tilis is ~O~ by USillg the ap~aratus described above in connection ~ith Figures ~ to 4, The installation phase of the tie-in operation can be the most tedious and dif~icult portion of the entire operation, Normally, the fabricated spool is lowered ~Id suspended proximate the gap into which it is to fit, with divers attempting to get it into proper position for insertion. tVhile it is apparent that the spool will fit into the gap, in practice the insertion o~ the spool can be dif~icult, The spool may be of the order o~ twenty feet long, and as much as four feet in diameter. With a typical wall thickness of about one and one-half inches, the spool might easily ~eigh several thousands of pounds and be quite cumbersome, It will likely be the case that several attempts will have to be made before the spool is finally inserted, Many attemps might be made that result in jamming of the spool and pipeline ends, in~licting damage to the surfaces of the faces of the spool and pipeline ends, leaving them scratched and marred, To lessen the prospect of flange damage through such binding, the clearance between the faces o~ the spool ~lange and the pipeline end flanges can be increased, This approach, however, requires that long bolting techniques be used that result in undesired stress being put into the pipe sections and spool, as well as the ~cLnts, Such long bolting also increases diver time needed for installation.
le method O f this invention involves determining _~7~

.
:. - - - -- . - , :

, --what c~l be called the "angle of entry" and "directiono~ approach" for the spool that permits insertion oi the spool ~vithout binding of the flan~es, and then providing . .
properly oriented guide snr~aces to guide the spool smoothly between the pipeline ends. By knowing the angle oi entry with accuracy, and by providing guides, the flan~e faces may be kept from striking one another ; during coupling to prevent damage or binding. In addition, - the clearance between the faces can be kept as small as ~ . .
the accuracy of the spool's dimensions permits, to make a good sealing joint.
, ~ .
The ~ollowing described methods and apparatus for installing a prei'abricated underwater spool relate to procedures involving the determination and use of the angle of entry and the direction of approach, and the proper orientation oi the guide suriaces.
With the information acquired by the spatial orientation surveying apparatus it is possible to determine the angle o~ entry and the direction o~ approach ior the preiabricated spool. The exact path to be i'ollowed by the spool can then be indicated by guides which may provide only an indication of the entry direction, but which preferably provide guide sur~aces alohg which the spool may be moved into proper position.
Reierring to Figure 8, there is schematically illustrated the spatial relation o~ two pipeline section ends to be Joined. The ends oi the pipelines to be connected are represented by two circules Sl, S2, One circle Sl lies in the plane Pl and the other S2 lies in plane P,. The : : -- . .
..

- -1~79~)60 planes are perpendicular to the centerline axes Ql and Q2 oi' the respective pipeline ends, The pipeline sections are also "open" to one another, iOe,, the centers l and 2 may be connected by an unobstructed imaginary line L.
Also, the pipeline ends represented have marked thereon the indexing points Zl and Z2~ respectively, to designate the orientation of the coordinate system of the surveying apparatus. The relation of these indexin~ points with respect to the top of each pipe is information that is supplied by the divers.Pre~erably, the indexing points should be close to the top o~ the pipeline and, ideally, should be aligned with a bolt hole `at the top. I~ the indexing points on the pipeline ends are at or near the top o~ each pipeline section, the spool may be constructed and oriented ~ollowing construction with the corresponding indexing points on the sur~ace o~ the spool directed upwardly, thus enabling an appreciation oi the spatial relation o~ the pipeline sections to be joined, and enabling an :Lnforrned choice of the most desirable angle of entry to be used. The indexin~ points are illustrated in positions not correæponding to the tops of the pipeline on Figure 8 in order to illustrate that the method may be carried out regardless oi Yvhere the indexing points are positioned, Referring again to Figure 8, planes Pl and P2, ~hich are the planes of the ~aces of the two pipeline sections ~; . . '- - ~,' -'. ' .- . ' - : . . ' , ::
, ' : ': :

Sl and S~, intersect at an angle 2c to form a line of intersection I, In~a~inary plane P5 bisects the an~le of intersection between planes Pl and P2, It will be noted, therefore, that the pipeline section ends Sl and S2 are disposed at an angle to one another and are also at different elevations. Accordingly, lines A-B and C-D, which are perpendicular to line I and extend through the centers of sections Sl and S2, are displaced ~rom one another by the distance L.
- In accordance with the "parallel" insertion method of this invention, the spool may be inserted between the pipeline sections Sl and S2 iD either of two æpeci~ic directions E2 and E3, In a~cordance with this insertion method, the spool ~aces are aligned to be substantially coplanar with the faces of the pipeline sections, and the spool is moved into place with the planar faces of the spool movin~ in a plane which essentially corresponds to the planes of the faces.
In accordance with the "wedge" insertion technique oi this invention, the spool is moved into -en~agement with the pipeline section ends most desirably from a~direction defined generally by line El, which is perpendicular to the line I of intersection between the plan~s Pl and P2 and is in plane Ps, lIowever, as will be developed hereinbelow, using the wedge technique, the spool is moved into position from the "open" side of the pipeline ~aces (i,e. ~rom a position wherein the centerliles o~ the spool may be connected by ima~inary lines to the centerlines of ~he pipeline sections without , :

.

intersecting the wall of the spool or the pipeline sections), and a plurality of angles of entry extending from the direction represented by E2 to the direction represented by E3 may be employed. Most advantageously, however, the spool is inserted from a direction normal to the line of intersection of the planes, that is, in a direction corresponding to line El.
In both insertion techniques, guides are arranged on both the pipeline ends and the spool ends extending beyond the perimeters thereof, which guides define the angle of entry and enable the spool to be moved positively into position.
Referring now to Figure 13~ the manner of accomplishing insertion of the spool between the pipeline ends using the parallet technique will be discussed. Once again~ pipeline ends Sl and S2 lying in planes Pl and P2 respectively are open to one another. Indexing points Z
and Z2 exist at abritrarily selected points on the circumference of Sl and S2~ respectively. Corresponding indexing points Z3 and Z4 on the end faces of the spool would align with points Zl and Z2~ respectively, when the spool is in position between the pipeline ends. Indexing points such as Zl and Z2 must necessarily be determined when the survey of the pipeline end sections is initially taken. Whether the surveying apparatus of the above-referenced application or a welded form is employed, it would be necessary to determine indexing points on the circumference of both pipeline sections in a fashion so that the corresponding indexing points could be found on the spool ~ ' - . '- ' "~

~79060 once constructed.
If the parallel technique is to be used, insertion of the spool will be from either direction E2 or E3 as illustrated in Figure 13. Assuming, for purposes of explanation, that the ocean floor lies below pipe sections Sl and S2 as illustrated in Figure 13~ the most expeditious manner of inserting the spool using the parallel technique would apparently be from direction E2. Once the most desirable direction of insertion of the spool is determined by a visual survey of the pipeline sections or by virtue of selecting the indexing points at a known position (preferably at the top of the pipeline sections as discussed above), guides may be provided on the spool and pipeline sections to assist the insertion procedure.
When using the parallel technique, the faces S3 and S4 of the spool 238 are moved in planes which are parallel to and virtually coincident with planes Pl and P2 of the faces Sl and S2~ respectively. By that is meant that some dimensional tolerance must exist between faces Sl and S3 and between faces S2 and S4 when the spool is in mating position between pipeline ends. Hence, the spool face will move in a plane which is parallel to the plane of the pipeline ends spaced from it by a distance corresponding to the tolerance which has been allowed. In general, the tolerances on each side may be maintained as low as about one-eighth of an inch or less depending upon the size of the spool to be inserted.
Accordingly, it will be appreciated that when using the parallel technique it is desirable to arrange ~uides G5 and G~ in planes which are parzllel to the planes of the faces S3 anA S~ and which slightly o~erhang the faces S3 and S~ in order to allow for the tolerance and to permit the spool to be ingrted between the pipeline ends without the ~aces of thespool and the pipeline'ends coming into contact. Accordingly, guides Gs and G6 are arranged coplanar with the faces S3 and S~ and extend in a direction indicated by lines Ml and M2 which are parallel to the line oi intersection I between planes Pl and P2 and pass through the center of the ~aces of the spool end.
Guides G5 and G6 may accordingly be positioned without reierence to the indexing points since the angle of intersection of planes Pl and P2 and line I may be computed by observing the relative angular disposition of the faces S3 and S4 o~ the spool, Accordingly, the line of intersection I may be determined and lines Ml and M2 may be determined to ,orient the guides. Once the guides are oriented in the planes parallel to the planes of the faces S3 and S4 and in directions as de~ined by Ml and M2, the guides are rigidly secured to the ends of the spool, ~ At that point, the angle ql between index point Z3 on spool end S3 and Ml which defines the center oi guide G5 may be determined, A similar angle 92 may be determined between index point Z4 and centerline M~ o~ the guide, Once angle ~1 has ~een determined an the spool, the disposition of the corresponding guide structure G7 on the pipeline end beneath the water may be readily _~3_ :. . . . . . . : , . .. . . .
,, . ~ ~ ' ' ' ' '. .

' determined, The guide structure G7 may then be taken down to the underwater p~pe section and af~ixed to the face Sl to define a planar guide surface which slightly overhangs the face of Sl to allow for tolerance as explained above. if G7 is positioned on pipe face Sl with its centerline displaced from indexing point Zl by angle ql, the guides will be aligned for insertion. A
similar procedure is employed to determine the angle 92 between index poin-t Z4 on the face of spool S4 and line M2, When guide structure G8 adapted to be fitted on pipe end S2 is then similarly oriented at an angular position of ~2 from index point Z2- guides GG and G7 will be aligned to enable insertion of the spool between the pipeline sections.
The method of insertion of the spool 238 between the pipeline sections may be accomplished using an alignment ~rame which will be discussed hereinbelow, Now with reference to insertion of the spool by the wedge technique, attention is directed to Figure 9. When utilizing the wedge technique, the guide sur~aces on the spool ends and the pipeline section ends are not disposed in planes parallel all guide surfaces are parallel to each other during the insertion procedure. In~much as the t~o pipeline section end faces Sl and S2 are disposed at an angle 2c with respect ~o one another,,the faces S3 and S4 o~ the mating spool define planes which intersect at the same angle. In order to construct parallel guides from these ~aces, it ~s necessary that the guides on each o~ the _54_ ~ .
' ~ , - ' , . . . . .

. . .

pipeline section cnds be arranged parallel and at angles to the planes of the faces of the ends, the sum of which angles is 2c. Similarly, the guides arranged on the ends of the spool must be parallel and form angles with the planes P3 and P4 of the faces o~ the spool S3 and S4 which likewise total 2c. In the illustrated en~bodiment of Figure 9, guides G3 and G4 have been disposed with their planar surfaces each forming an angle c with the planes of the faces of the spools P3 and P~. It will be understood that, ~or example, guide G3 might be disposed on the plane P3 of spool end S3. In such event, guide G4 would be required to be displaced parallel to guide G3 and hence would define an angle of 2c with plane P4. If the guides were arranged in this fashion, spool 238 in Figure 9 would be inserted between the pipeline ends along planes parallel to plane Pl o~ pipeline section face Sl. Hence, the angles between plane P3 of face S3 and guide G3 should be chosen based upon a visual survey of the pipeline section ends in order to determine the most expeditious angle o~ entry, It will be understood that the direction of entry may vary from an entry in which the spool is moved along lines parallel to plane Pl, along lines parallel to plane P2 (in which case the angle between guide G4 and plane P~ ~ould be zero and the an~le between guide G3 and plane P3 would be 2c) or along any set of parallel lines therebetween. In Figure 9, spool 38 is illustrated being inserted between the pipel.ine section ends along lines parallel to El which bisects the . .

. _55_ - ~ .

~. . . , . . -: '. ' . ' : - . ~. ~
: -, . ' . : '. ~ ' .. : ' ' ' - . . ' . . , ': ~ :~ :' -' -iO'79060 angle 2c. In the preferred mode of using the wed~-e techniqlle, the guide surfaces are placed on the side of the spool furthest from the pipeline secti~on ends when the spool is oriented for insertion therebetween.
~hen the guides are placed on the far side of the spool, they will form angles, the sum of which angles is 2c, and which angles recede from the face of the spool. On the other hand, the guide disposed on the pipeline section ends are in the illustrated embodiment of Figure 3 shown to extend toward the spooll In such instances, the guides Gl and G2 will form angles the sum of which is 2c which angles "overhang" the face of the pipeline sections.
However, it will be understood that if desired, the guide surfaces could be placed on the bottom side of pipe section end Sl as illustrated in Figure 9 and on the bottom side of the spool end S3, ~n such an instance, the guide sur~aces would de~ine a guide plane in the vicinity of GlA on Figure 9. Recognising that in insèrting a spool using the wedge technique, all guide surfaces are parallel, it is not material where those guide sur~aces are placed similarly relative to the faces of the spool and the pipeline section end to be ~oined. Thus, in ~igure 9, the plane of guide G3 is displaced a distance d from the center 03 of the spool face. Similarly, the plane of guide G is displaced a distance dl from the center l of the pipeline section end.

On the opposite ends of the spool, distances ~2 ~ndicate the same relative placement of guides G2 and G .
-sF

~ ' ' . -~079060 Once the desirable an1es between the guide surf~ees al~d the faces of the pipeline section ends and the spools are determined/ it remnins to determine the orientation o~
those guides relative to the axis of the spool and the pipeline section ends, It will be appreciated that if guide surfaces Gl and G3, ~or example, define endless planes which have openings around the pipeline section end S
and the spool end S3, there would be no di~ficulty in sliding the spool into mating relationship with the pipeline.
However, the guide surfaces Gl through G~ are, o~ course, finite in size and furthermore define tracks to permit only linear movement of the spool with respect to the pipeline section ends as will be discussed hereinbelow.
Accordingly, it is e~tremely important to orient the guides Gl through G4 relative to the pipeline section ends and the spool ends in order to permit insertion.
Referring to Figure 8 once again, indexing mark Zl on the perimeter of pipeline ~ace Sl was determined during the initial survey of the pipeline soction ends. Indexing mark Z2 on facè S2 was similarly determined. Thus, when spool ~8 is constructed, corresponding indexing marks which would align with indexing marks Zl and Z2 are placed on the perimeter ends o~ the spool ends S3 and S4.
With respect to orientation of the guides, assuming that it is desired to introduce spool238 between the ~ipeline section ends from direction El, perpendicular to line I defining the intersection of the ~7 anes Pl and P2~
the ~uides should be desirably centered over points N and N2 -')7-.
.: - . , , ' - - , , .

on the pipeline sections Sl and S~, Points Nl and N2 are defined by diameters of the pipeline sections Sl and S2 which are perpendicular to line I, Correspondin~ points to points Nl and N2 may be similarly defined ~n spool 238.
Inasmuch as the faces of spool238 define planes intersecting at an angle 2c, the points N and N2 on the spool may be geometrically ascertained, When points Nl and N2 on the perimeter of the spool are ascertained, the angles ~3 between point Nl and index point Zl~ and ~4 between N2 and index point Z2~ may be ascertained. The guides are then aff,ixed on the spool and centered over points Nl and N2 of the spool. The pipeline section guides are then carried to the underwater pipeline sections and placed thereon with the center of the guide being at the proper angle from the index point Zl and Z2 on the pipeline section ends.
Should it be determined that the angle of entry would be other than one perpendicular to line I, any such an~le of entry may be si.milarly computed.
In conducting the orientation of the flanges in accordance with this invention, an angle for orientation of the fla,nges should be chosen so that the spool encounters minimum interference from subsea obstacles, recognising that in the preferred embodiment the trasks or channels on the ~uides require that the spool be moved into position along lines or tracks on the guides. Th~ls, in the method discussed, the lines or tracks would be parallel to lines --58-- .

.. .

... . . . - . . . -. . , ~ :. ,-. .. ; : ' -.. . . . . . .

10'79060 AB and CD throu~h points Nl and N2, However, a direction for the tracks corresponding for example to lines UV and ~ might be chosen. In such a case, the guides would be centered over points Yl and Y2, and the tracks on the gui~es would be parallel to lines UV and WX, In such a circumstance, it will be noted that the planes of the guides will nonetheless be required to be parallel. Thus, if a guide were centered over points Yl and Y2, it will be understood that the base of the guide would not exist in a line within the plane of the face. (Note that points Rl an~ R2 at the base of guides Gl and G2 represent the end view of lines Rl and R2 which are in planes P and P2, respectively.) If parallel planes were to be centered over Yl and Y2, the guides would nonetheless be required to be in parallel planes such as planes of Gl and G2 and the face of the guide would be at an angle to the faces Sl and S2.
(See, e.g, dotted iine on Figure E12 showing the base of angle between the base of the guide and the plane o~
the face.) Hence, it is preferred, when using the wedge technique, to use an approach track perpendicular to the line of intersection between the planes of the pipeline end ~aces (i.e~ a trac'ls parallel to lines AB and CD).
Using this approach angle, the ~uides are not required to be turned to the side at the base thereof ~elative to the faces o~ the pipeline ends or the spool ends.
HoweYer, if such an angle of approach is desired because of existing subsea obstacles, the angle between , ., '.

.
.
: ' . - , . ~
.
.. .. . .
, ' . ........... ~ ~ : '' :
: :- , '. ' the desired approach track and the indexing points may be determined and the guides properly centered.
Usîng either the parallel or wedge techni~ue, the angle of entry and the ~uide orientation may be determined by geometrical layout or by computer, Since the sur~eying apparatus provides complete information about the orientation of the pipelines, the data supplied could be entered into a computer and processed according to programs that could calculate the best angle of entry and the necessary guide orientations with respect to the indexing points, and print out the ans~ver.
Aiter the guides ha~e been placed on the ends o~ the spool and the pipeline sections, the fabricated spool may be lowered to a position proximate the open gap between the pipeline ends, The guides in accordance with a preferred aspect of this invention will provide engageable surfaces or tracks to slide the spool into position. It is desirable that the guides on the pipeline and spool ends engage before the ends of the spool ~et close to the ends of the pipeline sections, Accordingly, the guide tracks on the ends o~ the pipeline sections should be su~ficiently long as to engage the mating guides on the spool ends before the spool ends touch the pipeline ends. It is, of course, possible to have the spool guides extend out and be long enough to engage the pipeline end-~uide trac~cs prior to contact between the pipeline and spool ends. Reference guide indicators could, for example, be visua] ~uides in the iorm of rods or otherwise that de~ine planes which indicate the n~anner in ~Yhich ~nd direction _~0_ .
.
, . ,~ .
- , .
' ,~ . ,'.`.' ' '' , ' , : ~

. - : :

from which the spool may be inserted. ~hile the alignment and positioning of the spool can be done by visually aligning the reference guide indicators, the work of the personnel performing the operation is greatly simplified ~vith mechanical guidance to assist in positioning the spool.
With regard to Figures 10, 11 and 12, guide 248a which provides a suitable structure for guides Gl through G~
is shown. The view of Figure 10 is that looking down the centerline axis of pipe section 240l perpendicular to the face of the flange. As will be appreciated, the an~le c may vary depending upon the orientation of the pipe ends to be connected as described above, Thus, ~or each situation a di~ferent guide arrangement may be required when using the wedge technique to provide guides having parallel surfaces which are skew by some angle such as c from the plane o~ the pipe face.
When operating by the parallel technique, the guides are parallel to the faces and hence angle c would be zero. In view of the necessity to accommodate various pipe section orientations, the guide 248a is comprised of a collar, generally referenced by the nu~ber 260, and a separate, but attachable guide section referen~e 270 Broadly speaking, collar 260 mounts onto the end of the pipe section in a manner to be rnore fully discussed hereinafter, such th~t the guide section 270 will be disposed at the proper angle of entry. Collar 260 includes a flange plate 262 welded to a backil~g plate 264 to provide a point of attachment for guide section 270.

; _61_ : - ~

' ' ' ' ' ~ , ' ,, ,, ', ' ~ ': ' :

The illustrated guide is for use in the wedge techniqlle when the a~roach angle is perpendicular to the line o~ intersection of the ~ipeline ~aces (l.e. through points Nl and N2 in Figure 8). If an approach angle such as W is desired to be used, the base o~ the plate will not be in the plane of the ~ace of the pipe 240.
The base of the guide may be disposed at some angle such as angle e as shown in Figure 12, Under such circumstances, it would be deslrable that ~ ge plate 262 be wider in order to facilitate mounting guide section 270 thereon.
When using the wedge technique, a~ter the angle of intersection of the planes Pl and P2 is determined, the necessary guide section 270 can be fabricated. It will likely be required that a ~ig be contrived such that good precision may be attained in the constructed guide section. In any event, the guide section 270 shown comprises a flange plate 272 that will match up with the flange plate 262 of the collar 260. Extending away from, an~ welded to, ilange plate 272 is a guide runner 274 having rails 273, 275 which, as shown in Figure 12, form a channel into which the mating guide 246a tG3) on spool end 239 is insertable. Guide section 270 is attached to flange plate 272, such that when guide section 270 is attached to collar 60 (see Fig. 11), it will be at the skew angle c.
A construction identical to that of guidP 248a may also be utilised for the other guide 248b. The mating guide pieces 246a and 246b ~ay be similar in design except, -62_ ' :: : . , ' - : . .
- .. - . ~ . :
.

.
-, 1079(~60 of course, that they ~vill not form a channel. The guide pieces 2~6a, 248a will have only a vertical plate that is a width that permits an easy, though close, fit into the channel on guide section 270~ Also with regard to Figure 12, it is pointed out that it may be desirable to provide guide section 270 with a support gusset 276, and similarly provide ~uide piece 246a with a gusset.
As well as being disposed at the proper skew angle, the mechanical guide used must also be properly positioned about the circumference of the pipeline section end or spool end to which it is attached in order that the guide path defined by the channels thereby will be at the proper angle. As discussed above, index points were employed to center the guides at the proper angle relative to the cir-cum~erence of the spool and the pipe section ends. The guide section 274 of the guide piece 248a must be designed ~-such that the top and bottom rails 273, 275 will be parallel to the line defined by the center of the spool as it is moved between the pipe sections. If desired, a reference guide indicator line, such line 280 may be scribed onto the mounting and ~uide sections of guide piece 248aO
Although proper setting of collar 2~0 alon~ the circumference of the pipeline end 244 could be done under~ater, it is pre~erable not to do so if at all possible because of the additional diver ~ime required and its attendant expense. Therefore, it is desirable to have a guide piece that is preset at the sur~ace, requirin~ only that the diver carry it down to the pipe end and bolt it into ~~3_ .

`~

place. The collar illustrated in Figures 10 and 11 provides the capability of predetermining the proper disposition of the collar 260 along the circumference of pipeline end 244.
Thus, when the spool is fabricated and the angle of insertion or angle of entry is decided upon, the guides may be affixed to the ends of the spool. Determination of the angle of entry or insertion technique to be used will determine the skew angle, if any, between the planes of the guide and the planes of the ends of the spool, and an adequate guide may be fabricated by welding a guide plate such as 274 at the proper angle to collar 260.
The guide is then oriented circumferentially so that the tracks of the guide on the spool define the desired angle of entry or insertion.
In order to present the collar 260 to dispose the center of the guide plate 274 at the proper angle with respect ot the indexing point on a pipeline end, the mating guide piece on the corresponding end 239 of the spool 238 of Figure 9 is first secured onto the spool and circumferentially disposed at the proper angle with respect to the indexing point. A dummy flange 244', ; having a size and configuration identical to that on the end of the underwater pipeline, is bolted to collar 260 of guide piece 248a~ as shown in Figure 11~ through mounting lugs 280~ 282~ 284, 286 carried in collar 260. As shown in Figure 11~ mounting lugs 280~ 282, 284 are disposed and slidable in groove 290 formed in collar 260. The lugs are retained in the groove by bolts 295, 296, 297 and 298 through collar 260 and the portion of the lugs within . - - . .

- ~ . :

1079~60 the ~roove. T~le bolts such as 298 are through slots such as 2~1 in the collar 2~0 which enable the lugs to be tiFhtened at various positions within the groove. The slot is sufficiently long to permit at lcast the lu~
to be aligned ovèr t~vo adjacent boltholes on the flange.
Thus, collar 260 to which guide runner 274 is attached is rotatable about the centerline of dun~y flange 244', riding on the mounting lugs. A cable 294 extends between ears 292, 293 and engages mounting lug 286 in a groove formed therein.
With the collar and guide runner mounted on the dummy flange 244', at approximately the proper angular displacement i'rom the indexing point, the ~uide piece 248a is then engaged with the mating guide piece on the spool, and the dummy flange 244' is held ad~acent the ~lange on the spool end 239. Bolts 295 to 298 are fitted loosely within slots 287, 289 and 291 enabling the dummy flange to be rotated through a limited angle. The dummy flange can then be bolted to the spool flan~e to secure ali~nment o~ the flanges, whi].e bolts 295, 296, 297, 298 extending through mounting lugs 280, 282, 2~4 and collar 260 are tightened to fix the relative positioning o~ the collar and the mounting lugs. Notice is taken as to which bolt hole on the dummy flange, with respect to the indexing point 21~ mounting lug 280 is matched with. The guide piece 2~8a may then be t~ en off the mating ~uide and the dummy flange removed.
Ib install the guide piece 248a properly on the pipeline end underwater, the only in~ormation that the diver _~5~

.
.. ~

1~79060 is required to have is knowledge of which bolt hole on the flange, with respect to the indexing point, the mounting lug 80 is to be matched with. Typically, the information required by the diver can be expressed, in the case of the illustrative example of Figure 11, as "the second bolt hole counterclockwise from the indexing point".
Referring to Figure 14 and 15, there is illustrated a suitable mechanical guide to be used in connection with the parallel technique. The guide is similar in many ways to the guide that is used with the wedge technique. -For example, the guide piece 320a that is to be mounted on the pipe end 302 in Figure 13 includes a collar 322 that mounts to the pipe end by four mounting lugs 324, 326, 328, 330 which are held in a groove in the collar. Upper and lower guide rails 332 and 334, respectively, extend slong the upper and lower edges of collar 322 to define a channel that is perpendicular to the centerline axis of the pipe end 302. As shown in Figure 15, the upper rail 332 is adjustable by means of a slotted hole therein and a bolt 333. As shown, rail 332 and the depending extension 331 is displaced a slight distance D
beyond the plane of the face of flange 303. The exact amount of displacement over the edge is adjustable by loosening bolt 333 and sliding rail 332 to the proper position. It is necessary to provide the clearance D
in order to prevent gasket 460 or another protrusion beyond the face of either the spool or pipeline flanges from being deformed as the spool is moved into position.

, . ' .
:: ~ . - . .. . . : . .. .
. : ,.. :

10'7~1)60 With rail 332 so disposed, the spool flange is permitted to slide past the gasket without coMing into contact with it.
As defined previously, the angle of entry is that angle between a radial line extending from the centerline of the pipe end to the indexing point thereon and a line tllrou~h the centerline of the pipe end that is parallel to the i~tersection o~ the planes of the pipe ends to be connected. Any reference guide indicator must be disposed on that line or de~ine a path that follows a course along that line, Accordingly, the guide path deîined by the rails 332, 334 must be along that line; and as shown, the rails are parallel to that line represented on guide piece 320a by a scribed line 340. The angle of entry is that between indexing point Zl and line 340 ~Yith guide 320a being preset in the same manner as the guide 248a of Fi~ures 10, 11 and 12.
Further illustrated in ~igure ].5 is the ~uicle piece 320b on spool 300 that mates with ~uide piece 3~0a. A collar 350 mounts to the end of the spool by mounting lugs, such as lugs 352 and 354, which are slidable in a groove 356.
Collar 350 .carries no guide rails, but is instead adapted to be slidably insertable into the guide channel defined between rails 332 and 334 of guide piece 320a. For proper mating o~ pipeline and spool ends, collar 350 must be disposed about the circumference of the spool end such that it is properly ali~ned at the angle oi entr~. ~resettin~.
of ~uide 320b is by rotatin~ collar 350 about the spool end until the proper angle with respect. to the inde~;,.n~
_G~_ .. . .

`' ~ -1~7~60 point thereon is reached.
Often, a spool that is to be positioned between two pipe sections will be of rather large and unwieldy physical proportions. Accordingly, it would be very difficult for work personnel to position the spool manually. It is desirable that some type of mechanical assistance be given in this regard, such as some type of power mechanism that will support and move the spool into position.
Referring to Figures 16 and 17, there is shown one suitable approach to providing the needed mechanical power assistance. Involved is an alignment apparatus 358 comprising a frame 360 standing on legs 362, 364, 366, 368 having feet 370, 372, 374, 376 attached thereon. The frame 360 includes a carriage mechanism, generally designated by the reference 380, which includes a beam 382 that extends across the opposing sides 361 and 363 of frame 360. A
carriage block, for example that designated by reference 384, is secured to each end of beam 382. The carriage blocks ride in a guide channel formed in the opposing frame rails 361 and 363. For example, carriage block 384 is movable along in guide channel 386. In addition to the carriage blocks on the ends of beam 382, there is disposed for lateral movement a power winch 388 riding in a track on beam 382 and having a line 390 depending therefrom which is attachable to the spool support 392. Suspending the spool from a single point on the frame assists in orienting the spool properly for insertioD.
Both carriage block 384 and movable winch 388 are adapted for powered movement along their respective guide `

. -~

: ` ,, -~ . . - : , 1~7gO60 channels. For example, hydraulic or electric motors could be utilised along with gear tracks to provide them with motive power. Movement of the carriage 380 and the operation of the winch is controlled through a control box 365. Easily manipulatable switches or buttons are provided on the control box to move beam 382 forward and backward relative to frame 360, to move winch 388 laterally along beam 382 and to move the winch cable 390 up and down.
The spool support 392 attached to winch line 390 serves to suspend spool 400 rotatably. As best shown in Figure 17, an I-beam 395 has a swivel connection 398 secured thereon which constitutes the point of attachment for winch line 390. Swivel connection 398 secured thereon constitutes the point of attachment for winch line 390. Swivel connection 398 is a ball and socket arrangement whereby the beam 395 is fully swinging and easily tiltable. Disposed near each end of beam 395 are spool hangers 394 and 396 which are movably adjustable on beam 395 to accommodate spools of various lengths and to balance the spool longitudinally from the single point of suspension.
Spool hangers 394 and 396 have an attachment member 402 that is slidable along and securable to beam 395 at its upper end and carries a bearing 404 on its lower end. The inner race of bearing 404 is movable not only rotationally with respect to the outer race, but is also laterally movable with respect to it as well. So constructed, spool hangers 394 and 396 hold a spool regardless of spool curvature.
By properly positioning spool hangers 394 and 396 on beam 3955 and securing hangers 394 and 395 to the proper .

1~79060 places on the pipeline, the spool is held in a level and balanced condition within the frame and also may be balanced around its longitudinal rotational axis. Most frequently, the spool will not be inserted between the pipeline ends from a level orientation. However, the balanced condition of the spool will facilitate diver manipulation of the spool to tilt or rotate the spool to orient it properly for engagement of the guides and insertion of the spool. Hence, the suspension systems disclosed will provide for balanced rotation around the longitudinal axis of the spool and longitudinal balance to permit tilting.
Referring again to Figure 9 and also to Figure 9a, one suitable suspension mechanism for hanging spool 238 from the winch line 290 is shown. The mechanism provides a single point connection in contrast to the two point connection scheme that is used in the mechanism of Figures 16 and 17. The winch line 290 attaches to an outer bearing race 420, which, as shown in Figure 9a, is a split-ring.
An inner race 422, also a split-ring, is rotatable within outer race 420, and is ~urther capable of lateral movement with respect to the outer race.
The spool is required to be rotatable to permit alignment and engagement of the guide pieces on the spool and pipeline ends. However, since the spool will typically not be a straight section, the mass of the spool will not be uniformly distributed about the ce~terline 424 of the spool.
The spool is first engaged at the longitudinal center of gravity, the point along its length with equal mass on . ' :: : :. -1~79060 each side of the suspension mechanism, to balance the spool longitudinally. The spool then must be balanced with respect to the axis of rotation of the bearing to place the center of mass CM of the spool on that axis (midway between the surfaces of race 420), and thereby achieve rotational balance around that axis. To provide adjustment of the spool 238 with respect to the bearing, spool 238 is mounted in the inner race by an adjustable auxiliary ring 426, which is al60 of a split-ring des gn.
Referring specifically to Figure 9a, the auxiliary ring is adjustable by three stanchions 428, 430, 432 that are carried by the innerrrace 422 and disposed symmetrically therearound. The stanchions comprise bolts that extend toward the centerline of the inner race and into contact with the auxiliary ring 426. The stanchions are adjusted to support the auxiliary ring within inner race 422 such that the centre of mass of the spool will be on the longitudinal axis of rotation of the bearing and an equal mass will be on each side of the axis.
In use of -these suspension devices, the spool will be suspended in the frame on board ship prior to being lowered for insertion between the pipeline ends. Hence, proper balance is achieved before spool insertion is began.
The foregoing description of the frontal entry method and the lateral entry method have been illustrated using pipeline ends having flanges. It is to be noted, however, that both methods and the mechanical guides described ~or use with each method may ~lso be applied to spool installation between pipe ends without flanges. In :, . . .
., ' , ~

107~060 such a case, the spool ends would be welcled to the pipe ends. If the ~elding of the snool is pre~erred, special split flan~es can be clamped onto the spool and pipe ends, presenting a sil~ulated flanged end. Mechanical guides as previollsly described can then be secured to the flanges, The guide used will, of course, depend upon the particular method being used, After the spool is inserted between the pipe ends according to one of the methods described herein, an alignment frame with clamps can be secured to the spool and pipe ends to hold them during the welding operation. The use o~ alignment frames and welding clamps are well known and form no part of this invention. With the spool and pipe ends being held in fixed relation for welding, the rnechanical guides and split flanges can then be removed. Welding takes place in a conventional manner.
Assuming that a flange connection is desired, it is important to protect against leaks. As a rule, leakage is primarily attributable to improper initial alignment of the flanges. Thus, if flanges are bolted together to force the flange faces into alignment, leaks are pro~able. The apparatus and techniques o~ the present invention serve to reduce greatly spool ~lange and pipe flange misalignment. To enhance leakage protection further, the spool may advantageously be fitted with the flange illustrated in ~igure 15. The flange is adapted to match the ring joint flanges on the pipes.

-72^

': ' . - ~ .- , ' . - :
' ' ~079060 The flange g';0 shown in ~igure 15 uses what may be termed a piston type ring seal 454 to provide secondary sealing, retention of the flat seal 460, and centralis~.tion of the flanges 450 and 303 to relieve shear stresses on the seal ~60 and the bolts, Specifically, the flange has a deep groove 452 in which a ring seal 454 is disposedO Double 0-ring seals 456 and 458 are also provided that extend about the inner and circumferential surface of ring seal 454, An upper passage 462 and a lower passage 464 extend from the rear o~ recess groove 452, opening to the outside behind the flange. Near the outer opening of the passages, tapering threads are provided for accepting a tapered plug thereinto to close off the passage.
Installation of this type of spool ilange involves going down with passages 462 and 464 unplugged, permitting - equalisation of pressure on each side of seal 454, After the spool is in position bet~veen the pipeline ends to be connected, and with gaslcet 460 in contact, the lower passage i9 closed and water pressure is applied throueh the upper passage 462, The water pressure applied must be sufficient to cause a piston type ring seal 452 to be urged from within recess groove 454 and engage a groove 4G5 in the opposing flange 303, which groove is concentric with and o~ an equal diameter to the recess groove 452.
T-;pically, only about lO0 pounds per square inch (c.6~0 kNm 2) pressure will be necessary, Engagement of the ring seal 454 with groove ~66 t'~ill cer.tralise the flanges, .. ~ . . . . .
.
,~ ., .; .
~.-~ ' ' ' . ' ' ~ ~79060 With water pressure being maintained, all bolts aretightened. The lower plug may then be removed and a check valve placed in upper passage 462.
With ring seal 454 properly positioned, a hardenable material, such as an epoxy resin, is introduced through the upper passage into groove 452 behind seal 454, causing any water therein to be flushed out through the lower passage. The lower passage is next plugged with plug 470 and sufficient pressure is applied to the flow of hardenable material to fill completely the void in groove 452 behind seal 454, with the check valve 468 in the upper passage retaining pressure on the seal 454. A second plug 472 may then be inserted over the check valve. -~
Variations from the disclosed embodiments may be made. For example, the guides, which are disclosed as positioned on one side of the pipeline and spool, might straddle the pipeline. The method disclosed will enable determination of a number of useful guide planes which may be used. Furthermore, the ~uides need not be planar as illustrated but need only define planes. Thus, for example, a pair of rods on the spool whi~h are received into sockets mounted on the pipe might be used. Alternatively, the guide on one member might include wheels designed to rise in tracks of the other. The apparatus for suspending and inserting the spool may also vary from the disclosed embodiments. For example, the spool could be suspended from an A-frame and be manipulated positively by means of a hydraulic system. Nonetheless, balancing the spool ~ .

.. ..

-for tiltin~ or rotational rnovemen " is desirab].e to minimise ef:~ort, whether by hand or mechanically, in orienting the spool. The above and other variations will be appreciated hy those skilled in the art.

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Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for connecting two stationary misaligned pipes comprising:
affixing a frame at the end opening of each pipe, each frame carrying a gimbal assembly defining in a reference position a pair of coplanar mutually perpendicular axes lying in a plane parallel to the face of the end opening;
securing the respective ends of an extensible elongate member to each gimbal assembly by connections which serve to reorient each gimbal assembly to a unique reoriented position determined by the direction at which the elongate member interconnects with the gimbal assembly;
measuring the angular displacement of the gimbal assembly about its axes to indicate the movement of each gimbal assembly from reference positions to reoriented positions;
measuring the length of the extensible member as it is secured to the gimbal assemblies;
measuring the angle, projected on a plane perpendicular to said extensible elongate member, between the axes of each gimbal assembly; in the reference positions fabricating a spool for interconnecting the pipe ends according to the defined spatial relationship; and interconnecting the two end openings with the spool.

2. The method of claim 1 wherein the step of fabricating the interconnecting spool includes:
reconstructing the spatial relationship of the misaligned pipelines at the fabrication site by pipe end simulators mounted on a pair of spaced devices having two mutually perpendicular axes of rotation giving free angular movement in two directions that are set to place the pipe end simulators at the same disposition as the misaligned pipe ends, according to the registered parameters transmitted from the underwater location; and assembling appropriate sections of pipe to form a spool that interconnects between the pipe end simulators.

3. The method of claim 1 wherein the step of fabricating the interconnecting spool includes:
entering the registered values of said parameters into a computer programmed to develop the specifications of the spool sections; and assembling sections of pipe conforming to the specifications developed by the computer to form a spool that will be of a config-uration adapted to interconnect the ends of the two misaligned pipe ends.

4. A method of determining the spatial relationship between two misaligned pipes comprising the steps of:
placing a frame including a gimbal assembly on each pipe end to define, with respect to a known reference point on each pipe, a pair of three-axis orthogonal coordinate systems having their respective origins at known positions relative to the centers of the two pipe faces, a first coordinate system having a pair of mutually perpendicular X, Z axes defined by the axes of the first gimbal assembly and lying in a plane parallel to the first pipe face and a Y axis defined by the centerline of the first pipe, and a second coordinate system having a pair of mutually perpendicular X', Z' axes defined by the axes of the second gimbal assembly and lying in a plane parallel to the second pipe face and a Y' axis defined by the centerline of the second pipe;
measuring by direct readings the following geometric parameters:
(a) the center-to-center distance between the origins defining a line segment, L1;
(b) the angular displacement, .THETA., of L1 about the Z axis;
(c) the angular displacement, .PHI., of L1 about the X axis;
(d) the angular displacement, .THETA.', of L1 about the Z' axis;
(e) the angular displacement, .PHI.', of L1 about the X' axis; and (f) the angular displacement, .gamma., between axes X, Z and axes X', Z' as projected onto a plane perpendicular of L1.

5. A method as claimed in claim 4 wherein parameters (a) and (f) are measured by an extensible member connected between the origins and which has at least one end which is rotatable relative to the coordinate system in the pipe face to which it extends and parameters (b), (c), (d) and (e) are measured by a pair of gimbals, one gimbal being mounted at each of the origins.

6. A method as claimed in claim 4 including the step of measuring the parameters by electrical sensing means mounted on the member and the gimbals.

7. A method as claimed in claim 5 including the step of transmitting electrical signals representative of measured values of the parameters from the pipe location to a location remote therefrom.

8. A method for generating the necessary parameters for construction of a spool to connect two misaligned pipes utilizing a measurement tool including two frames adapted for being mounted on the respective pipe faces and an elongate connecting member extending between gimbal assemblies on each frame, comprising the steps of:
mounting a frame on each pipe end in a known position with respect to a reference point on the pipe, each frame including a gimbal assembly;
each said gimbal assembly having a portion which is orientable about two mutually perpendicular gimbal axes, the first of which is parallel to the face of the pipe and with the axis of the pipe defines a three-axis orthogonal coordinate system, the first gimbal axis of each gimbal assembly being mounted in a known position with respect to a reference point on the pipe face;
extending the elongate connecting member between said gimbal assemblies;
said connecting member having ends which are adapted to interconnect the orientable portions of said gimbal assemblies with the first gimbal axes of the gimbal assemblies in a determinable angular position relative to one another as measured in a plane perpendicular to said connecting member;
positioning the orientable portions of said gimbal assemblies to be connected with the connecting member;
connecting said connecting member between the orientable portions of the gimbal assemblies;
measuring the length of the connecting member in the interconnected position;
measuring the rotational displacement of each orientable portion of each gimbal assembly about each of the axes of the gimbal assembly; and measuring the angular displacement between said first axes of said gimbal assemblies as projected upon a plane perpendicular to said connecting member.

9. The method of claim 8 wherein the ends of the connecting member are rotatable relative to each other and including the step of rotating at least one end of the connecting member relative to the orientable portion of the gimbal assembly to which it connects in order to interconnect the connecting member with the orientable portions of each of the gimbal assemblies, with each end of the connecting member in a known angular attitude with respect to the first gimbal axis of the gimbal assembly to which it connects.

10. The method of claim 8 wherein the steps of measuring the length of the connecting member, measuring the rotational displacement about the gimbal axes, and measuring said angular displacement are performed by electrical sensing means operating to produce an electrical signal functionally related to the measured values.

11. The method of claim 10 wherein the electrical sensing means are variable impedance electrical devices.

12. The method of claim 10 including the step of transmitting the measured values of length of connection member, rotational displacement and angular displacement from the location of the misaligned pipelines to a location remote therefrom.

13. The method of claim 12 wherein the step of transmitting the measured values includes transmitting electrical signals representative of the measured values over wires.

14. A method for determining the spatial relationship between two misaligned pipes laying on the floor under a body of water comprising the steps of:
placing a frame on each pipe end, each said frame including a gimbal assembly having a gimbal portion orientable about two mutually perpendicular axes, the first of which is parallel to said pipe face and defines together with the axis of the pipe a three axis orthogonal coordinate system with the gimbal portions at the origins thereof;
measuring by a first transducer the distance between the gimbal portions at the origins of said coordinate systems by connecting an elongate member therebetween;
measuring by second through fifth transducers the displacement of the two gimbal portions about each of the two axes about which the gimbal portion of each gimbal assembly is orientable;
measuring by a sixth transducer the angle between the projections of each of the gimbal axes parallel to the pipe face on a plane perpendicular to said elongate member; and reading out said parameters to a remote location by polling said transducers.

15. A method for determining the spatial relationship between two misaligned pipes comprising the steps of:
mounting a frame proximate the end of each pipe in a known position with respect to a reference on the pipe, each frame including a gimbal assembly with rotational freedom about two mutually perpendicular gimbal axes which, in a reference position parallel to the face of the pipe and together with the central axis of the pipe, define a three-axis orthogonal coordinate system;
extending between the gimbal assemblies a straight elongate connecting member having at each end a registry portion coupled before measurement with a mating portion on one of the gimbal assemblies to be in a known angular position relative to the gimbal axes of the gimbal assembly to which it is coupled;
securing the registry portions to the mating portions of the positioned gimbal assemblies;
measuring the length of the connecting member in the extended position;
measuring about each gimbal axis the rotational dis-placement from the reference position to the registered position with the connecting member extending in registry therebetween and measuring the rotational angle between the points of registry indicative of the angular displacement between the respective mutually perpendicular axes of the gimbal assemblies as projected on a plane perpendicular to said connecting member.

16. The method of claim 15 wherein the registry portions at each end of said connecting member are rotatable relative to each other about the axis of the connecting member and including the step of rotating one end of the connecting member relative to one of the gimbal assemblies and positioning each gimbal assembly about its axes to receive the ends of the connecting member so that the assembly mating portion may couple with a respective registry portion of the connecting member.

17. A method as claimed in claim 15 wherein said pipes have flanged ends adapted to be coupled to a mating member with bolts and wherein each said frame comprises a template and said mounting step includes attaching a template to a flange at the end of each pipe.