TREATMENT OF INTERNAL FACES OF PIPE BENDS

Abstract: Apparatus and process for internal surface modification of a pipe bend or elbow (herein referred to as a bend), wherein a bend (20) is positioned on mounting means (16) of a support frame (14) rotatable about a principal axis (X). The bend (20) is positioned such that it has a radial section thereof positioned substantially in a work plane perpendicular to axis (X) and such that the section is substantially centered on axis (X) during rotation of the frame (14) about axis (X). A treatment head (22) is positioned at the work plane, adjacent axis (X), and operated to effect modification of an annular zone of the internal surface of the bend (20), around radial section, as the frame (14) and the bend (20) mounted thereon is rotated under the action of drive means (12) to move the zone across the treatment head (22).

Description: TREATMENT OF INTERNAL FACES OF PIPE BENDS This invention relates to the internal facing or surface modification of pipe bends and elbows (hereinafter referred to as bends) . The invention has particular application in providing an abrasion and/or corrosion resistant lining in bends formed of metal, such as by weld deposition. However, depending on the nature of lining to be provided, the invention is applicable to the lining of bends of material other than metal, such as bends of plastics or ceramic material. Also, it is to be understood that the invention has application in providing a lining by techniques other than weld deposition, such as flame spraying techniques involving plasma and oxygen-acetylene flame spraying of metal and/or ceramic, and spraying techniques other than flame spraying. Additionally, the invention has application in surface modification of the internal surfaces of bends by controlled surface heat treatment, using a heat source with or without quenching. According to the invention, there is provided apparatus for internal surface modification of pipe bends and elbows (herein referred to as bends), including a support frame; drive means for rotating the frame about a principal axis; the support frame having mounting means adapted to position a bend thereon such that the bend has a radial section thereof positioned substantially in a work plane perpendicular to said axis such that said section is substantially centered on said axis during rotation of the frame about said axis; and a treatment head positionable at said work plane, adjacent said axis, and operable to effect modification of an annular zone of said surface, around said radial section, as said frame and a bend mounted thereon is rotated under the action of said drive means to move said zone across the treatment head. The invention also provides a process for internal surface modification of pipe bends and elbows (herein referred to as bends), wherein a bend is positioned on mounting means O-f. a support frame rotatable about a principal axis; the bend being positioned such that it has a radial section thereof positioned substantially in a work plane perpendicular to said axis and such that said section is substantially centered on said axis during rotation of the frame about said axis; a treatment head being positioned at said work plane, adjacent said axis, and operated to effect modification of an annular zone of said surface around said radial section as said frame and the bend mounted thereon is rotated under the action of drive means to move said zone across the treatment head. The mounting means may comprise a cradle in which the bend is releasably mounted. The cradle may be configured to receive a bend of a given external diameter and radius of curvature, with the overall apparatus being intended solely for use for the internal surface modification of bends of substantially the same form. Alternatively the cradle, or the support frame and its cradle, may be separable from the drive system to enable replacement with another on which bends of a different external diameter and/or ' radius of curvature can be accommodated for internal surface modification on the one machine. In a still further alternative, the one cradle may be adjustable to enable bends of a range of diameters and/or curvatures to be mountable thereon. At least for a bend of a given radius of curvature, the support frame may be movable relative to the drive system. Preferably the frame is so movable to enable successive radial sections of the bend to be positioned substantially perpendicular to, and centred on, the principal axis of rotation. For this purpose, the frame preferably is pivotal about a pivot axis which is at right angles to, but laterally offset from, the principal axis, with the pivot axis extending through or closely adjacent the centre of curvature of the 1Q bend when the bend is mounted on the frame. The overall arrangement of the support frame and drive system preferably is such that, during rotation of the frame about the principal axis, the bend is rotated with the frame so that its positioned radial section remains in the work plane and centered on the principal axis. The treatment head may be one operable to apply material, such as weld metal, to the internal surface of a bend. The treatment head preferably is positionable so that, during rotation of the frame and a bend mounted thereon, it is 20 adapted to apply material to that surface in a substantially annular application zone parallel with and in, or adjacent, the work plane. That is, the treatment head is adapted to provide material within, and around the internal surface of the bend at the positioned radial section of the bend. Thus, with the frame moved to position successive radial sections of the bend into the work plane, the treatment head is operable to apply material in successive substantially annular application zones along the bend, to progressively build up a facing over the internal surface of the bend. 30 A portion of the support frame, such as the cradle F-T thereon, may be movable, to position successive radial sections of the pipe bend in the work plane, by a step-wise or continuous movement. For this purpose, indexing movement means, or a continuous movement means, preferably is provided for adjusting the position of the cradle and a bend mounted thereon relative to the drive system by pivoting movement of the cradle on its pivot axis. Each such alternative movement means may be independent of, or actuated by, the drive system. However, in each case, it is preferred that operation of the movement means is substantially synchronized with rotation of the support frame. That is, the movement means preferably enables the treatment head to operate to apply material in each annular application zone, in at least one substantially complete transversal of each zone, during each rotation of the frame by the drive system. As will be appreciated, such synchronized operation of the movement means will give rise to a different material application form depending on whether the movement means provides indexed or continuous movement. Thus, with indexed movement of the support frame, successive application zones will essentially be of an true annular form and adjacent each other. However, with continuous movement of the frame, each application zone will be one revolution of an overall helical form defined by successive application zones. The arcuate or arc length of a bend of course decreases progressively from a radially outer maximum to a radially inner minimum. A number of possible results can be obtained with operation of the apparatus as so far described if it is assumed that the support frame and a bend mounted thereon are rotated by the drive system at a constant speed and the treatment head remains stationary. The most important of these results are either that: (a) the inner surface of the bend will be fully lined with applied material, due to successive application zones being sufficiently close along the radially outer arc length of the bend as to merge into or overlap each other, or (b) the inner surface will not be fully lined, due to successive application zones not merging or overlapping at all, or merging or overlapping along the radially inner arc length of the bend but diverging toward the radially outer arc length. In general, each of these results is undesirable, with result (b) being contrary to the normal objectives in providing a lining. Result (a), if it achieves a required amount of applied material per unit area along the radially outer arc length of the bend, will mean that a substantially greater amount of applied material is provided per unit area along the radially inner length. Result (b) may achieve a required amount of applied material at the radially inner arc length but, even if this is so, exposed inner surface of the bend between successive application zones at radially outer arc lengths will mean that such exposed surface does not derive such protection as is intended to be provided by the lining. The apparatus preferably is adapted to provide a complete lining over the full inner surface of the bend, over at least a required arcuate length of the bend, which is of at least minimum thickness throughout. For a lining to provide corrosion resistance, this enables a lining which is of substantially constant thickness throughout. For an abrasion resistant lining, this may necessitate a lining which is of greater thickness at radially outer arc lengths of the inner surface of the bend that at radially inner arc lengths, since in use of bends in pipe lines to convey abrasive materials, the abrasive action of those materials is greater at the outer area of the bend inner surface. In a first arrangement according to the invention, in which the treatment head may be stationary during use of the apparatus, the drive system is operable to rotate the 10 support frame and a bend thereon at a rate which varies between a maximum and a minimum in each revolution. In that arrangement, the rate of rotation is a maximum and a minimum when the treatment head is applying material at the radially . inner and radially outer arc length respectively, so that the amount of material applied and, hence, the thickness and to a degree the width of the application zone, progressively increases from the radially inner to the radially outer arc length. In a modification of that first arrangement, the 20 drive system may be operable to rotate the support frame and a bend thereon at a substantially constant speed. However, in this instance, means for supplying material to be applied by the treatment to the treatment head is operable to vary the rate of supply of that material, in each revolution. In the modification, the rate of supply is varied between a maximum and a minimum when the treatment head is at the radially outer and radially inner arc length, respectively. Operation again is such that the amount of material applied and, hence the thickness and to a degree the width of the application zone, 3T Q progressively increases from the radially inner to the FY. radially outer arc length. In such modification, the drive system may be operable so as also to vary the rate of rotation, as described in the preceding paragraph. In each of the first arrangement and its modification, variation in the rate of revolution and rate of supply, respectively, preferably are in a continuous cycle. However, in each case, it may be such that the thickness of applied material is substantially constant or such that this thickness increases with increase in width of the application zone. In each case, the variation may be such that successive application zones merge or partially overlap, so that a continuous lining is formed over the inner surface of the bend; the lining preferably being either of substantially uniform thickness or of increased thickness at radially outer arc lengths compared with the thickness at radiually inner arc lengths. In a second arrangement one or both of the rate of revolution and the rate of supply of material to be applied may be substantially constant. However, in this arrangement, the treatment head is mounted so as to be movable to transverse an oscillating path in a plane containing the principal axis about which the support frame is rotatable by the drive system. The arrangement is such that oscillation of the treatment head in that plane is substantially parallel to arc lengths of the bend at which material momentarily is being applied, and laterally with respect to the application zone being formed. Oscillating means, for imparting such movement to the treatment head, preferably is operable to vary the oscillations in amplitude and, if required, also in frequency. The overall operation of the oscillating means principally is to vary the amplitude of oscillation of the treatment head. Such variation preferably is between a minimum when the treatment head is applying material at the radially inner arc length of the bend, and a maximum when at the radially outer arc length, so that the width of the treatment zone increases from the inner to the outer arc length. The oscillating movement of the treatment head may 10 be combined with the features of the first arrangement or its modification, to enable overall control of the amount of material applied around an application zone. Variation in the rate of revolution of the support frame most preferably is used in such case. As will be appreciated, when rotating a bend so that a radial section of it is located in a work plane, with the centre of that section retained on the axis of rotation, other parts of the bend curve away from the principal axis. Thus, if the radial section is a central section of the bend, each 20 end of the bend may be fully to one side of the principal axis and rotate bodily around that axis. Positioning of the treatment head within the bend must be able to accommodate this. The apparatus preferably includes a treatment head carrier arm on one end of which the treatment head is mounted. The carrier arm may be either retractable or removable to enable a bend to be secured on the support frame, or the bend may be receivable over the one end of the carrier arm after securing the bend on that frame. In each case, with 3.0 a bend so secured, the carrier arm then is positionable so as FY to extend into the bend at an angle to the principal axis with the treatment head located at or adjacent the work plane in which a radial section of the bend is positioned. The carrier arm, when so positioned, preferably is in a plane containing, or closely parallel to, the principal axis. That plane preferably also is one in which, or closely adjacent to which, the centre of curvature of the bend is located. The angle at which the carrier arm extends with respect to the principal axis is dictated by the radius of 10 curvature and diameter of the bend, as well as the transverse dimension of the arm. Also, the extent to which the carrier arm extends into the bend is dictated by these factors, as well as the arc length of the bend. For maximum utility of the invention, the parameters of the bend should be such that carrier arm can extend through at least slightly in excess of half the arc length of the bend. Thus, with the arm received into one end of the bend, the internal surface of at least half the bend can be lined, after which the bend is reversed to enable lining of its remaining internal surface. It will 20 be appreciated that the parameters of bends, other than those of quite large radii of curvature and internal diameter, may preclude full lining without the need for reversal of the bend after partial lining. The treatment head most conveniently is maintained in a substantially constant orientation. Also, apart from oscillating movement of the treatment head, as foreshadowed above and as explained further in the following, the treatment head is retained substantially in the work plane in which a given radial section of the bend is positioned for application 30 of material therearound. Thus, in such case, the rotation of ET. the bend is relative to and around the treatment head therein. In order to permit such relative rotation, at least when the given radial section of the bend is one spaced from the end of the bend through which the treatment head carrier arm extends, it is necessary that the carrier arm is moved relative to the principal axis, synchronously with rotation of the bend. The preferred form of movement of the carrier arm relative to the principal axis is most readily understood by considering that arm as having a longitudinal axis. In that movement, the axis of the arm traces out a cone of revolution at the apex of which the treatment head is located. The cone of revolution most preferably has its axis substantially co-incident with, or at a slight angle to, the principal axis; while the carrier arm preferably remains in a substantially constant orientation relative to its own axis. To facilitate such movement of the carrier arm, while maintaining the treatment head in a substantially constant orientation, the treatment head preferably is pivotally mounted on the end of the carrier arm. Also, the carrier arm preferably comprises a pair of elongate members, secured in a parallelogram linkage arrangement by a plurality of link members. The treatment head may be one such link member, or it may be mounted on or in a fixed relation to one such link member. Such movement of the treatment head carrier arm may be provided by arm rotation means engaged with the carrier arm remote from the treatment head and driven by, or independently αf, the drive system for rotating the frame about the principal axis. In one arrangement, the arm rotation means comprises a hub mounted for rotation on the principal axis. Extending from hub, laterially with respect to that axis, the arm rotation means has at least one bracket; with there preferably being two brackets spaced along the principal axis. The or each bracket has mounted thereon an annular ring which has a ring axis laterally offset from the principal axis and preferably substantially parallel to the principal axis. In the or each such ring, there is an arm support member relative to which the ring is rotatable; the treatment head carrier arm extending through, and being pivotally mounted in the or each support member. The arrangement is such that, with rotation of the hub of the rotation means, in synchronism with rotation of the support frame by the drive means, the or each bracket and its annular ring is rotated around the principal axis. During such rotation of the or each ring, the latter rotates relative to the support member therein; the carrier arm pivoting relative to the ring axis but remaining in a constant orientation relative to its own axis. The treatment head may be reciprocable laterally of an application zone, during the application of material to form such zone. Most conveniently, the amplitude of reciprocation of the treatment head is variable so that the width of the application zone increases from a minimum at the inner arc length of the bend to a maximum at the outer arc length. Reciprocation of the treatment head may be provided by reciprocating means acting on the treatment head carrier arm, to cause that arm to reciprocate longitudinally, with resultant reciprocation of the treatment head. In one arrangement, the reciprocating means comprises a cam member operable to cause reciprocation of a ca follower. Movement of the cam follower may be applied to relatively pivotable members by which the treatment head carrier arm is mounted in the or one arm support member, to thereby impart longitudinal reciprocating movement to the carrier arm. Preferably, the or each arm support member is a generally annular spider within which there is located a yoke member. The latter is mounted within its spider so as to be pivotable on a first axis extending in a plane which is substantially perpendicular to the principal axis. Within the yoke member, there is a pivot or gimbal member in or on which the carrier arm is pivotally connected; with the pivot or gimbal member being pivotable on a second axis parallel to the first axis. Reciprocating movement of the cam follower is applied to the yoke member and, through the pivot or gimbal member, to the carrier arm. Application of the reciprocating movement of the cam follower to the yoke member preferably is by means of a lever system. However, resultant reciprocation of the carrier arm with the arrangement so far described will ' be of constant amplitude. Most preferably, a pivotable connection between two lever arms of the lever system is adjustable longitudinally of one of those lever arms, parallel to the first and second axes, by adjustment means to provide required variation in the amplitude of reciprocation of the carrier arm and, hence, the treatment head. The adjustment means may include an eccentric surface around the annular ring of the arm rotation means, or the one of those rings having the relatively pivotable members an which the reciprocating means is operable. In such case, the adjustment means may include a first plate member adjustably mounted on the spider of that ring for limited movement of the plate member parallel to the first and second axes of the pivot members within that spider. The adjustment means further includes a roller mounted on the first plate member and engaging the eccentric surface on the, or the one ring, such that the plate member is reversably adjusted during rotation of the ring with the arm rotation means. The reciprocating means is mounted on a second plate member which preferably is substantially parallel to the first plate member; with such adjustment of the first plate member causing resultant adjustment of a pivotal connection, between two lever arms of the reciprocating means, longitudinally of one of those arms. As a consequence, reciprocating movement imparted to the carrier arm and, hence, to the treatment head, varies in amplitude with rotation of the arm rotation means. Where the apparatus of the invention is adapted for lining a bend by weld deposition, the treatment head comprises a weld head. Weld deposition most conveniently is by use of a consumable electrode wire, received by the weld head from a wire supply source. However, the apparatus can be used for bulk welding in which an alloy powder also is received by the weld head from a powder supply source; the powder being melted with electrode wire to form a weld deposit of a required composition. Electrode wire for a welding operation may be passed along substantially the full length of the weld head carrier arm, to the weld head. For this purpose, a wire feed device may be mounted on the carrier arm, such as at the end of that arm remote from the weld head. The wire feed device may be of cαnventional form, with weld wire passing to that device from a wire supply spool mounted on or adjacent that remote end of the carrier arm. From the feed device, the wire is passed along a conduit defined by or extending along the carrier arm to the weld head. Preferably, the wire passes from the conduit to the weld head, via an guide-way which changes the direction of longitudinal movement of the wire from a path parallel to the carrier arm to a direction substantially parallel to the work plane. Such guide-way preferably is a : curved tube or channel and, in the case of a channel, may have a series of rollers therealong for constraining the wire to follow a required curved path defined by the guide-way. Where bulk welding is to be performed, a powder feeding device may be used for passing metal alloy powder along substantially the full length of the weld head carrier arm. The feeding device preferably is mounted on the remote end of the carrier arm, and may receive powder from a supply which also is on or adjacent that end of the arm. In one convenient arrangement, the powder is passed to a supply conduit of the feeding device for movement in the conduit, along the carrier arm, to a powder metering device located adjacent the weld head. The feeding device may comprise an inlet chamber for the supply conduit into which powder is received from the source, and a plunger within the chamber for advancing successive charges of powder into and along the conduit. The chamber may be defined by a sleeve in which the plunger is co-axially mounted, with the sleeve being intermittently advanced along an inlet portion of the supply conduit by a cam member, against the action of a return spring acting on the sleeve and which thereafter, repositions the plunger for its next advance. The powder metering device may be of conventional form. It acts to receive powder from the supply conduit, and to discharge the powder adjacent the electrode wire stick-out from the weld head. In an alternative arrangement, a hopper for metal alloy powder and a powder metering device are mounted on the weld head carrier arm at a position remote from the weld head. A steady flow of powder issuing from the metering device is passed along a conduit, or along a thin endless conveyor, extending along the carrier arm for discharge therefrom adjacent the electrode wire stick-out from the weld head. In a further alternative, the metal alloy powder can be provided as core material in an electrode wire of hollow sheath form. In this instance, the weight ratio of sheath to core per unit length of the wire, and the composition of the sheat and core, are chosen to achieve weld metal of suitable composition for the required properties in the resultant applied material. Clearly, a similar relationship is to exist where the powder is provided by a powder metering device although, in this case, operation of the metering device can be regulated to vary the composition of the applied material if required. In order to more clearly describe the invention, reference now is directed to the accompanying drawings, in which: Figure 1 is a perspective view of a bend mounting and rotating sub-assembly; Figure 1A is a plan view of the sub-assembly of Figure 1; Figures 2 and 2A correspond to Figures 1 and 1A, but show an alternative drive arrangement; Figure 3 shows in side elevation, partly in section, a carrier arm sub-assembly located to the right of th sub-assembly of Figures 1 and 2; Figure 3A shows a perspective view of the sub-assembly of Figure 3; Figures 4 and 5 show, on an enlarged scale, alternative spider and yoke assemblies for the sub-assembly of Figure 3; Figure 6 shows the spider of Figure 5 in an axial elevation; Figure 7 is a perspective view of the yoke of Figure 5; Figure 8 is a perspective view of a gimbal component of Figure 5; Figure 9 shows oscillating means for oscillating the carrier arm; Figure 9A shows a sectional view on line IXa.-IXa. of Figure 9; Figure 10 is a perspective view of the arrangement of Figure 9; Figures 11 to 13 show in detail components of the oscillating means of Figure 9; Figures 14 and 15 show in side and axial elevation, respectively, a metal powder supply arrangement; Figure 16 shows an alternative form of a component shown in Figure 14; and Figures 17 and 18 show respective views, one a plan view and the other a side elevation, of a powder feeder device. The drawings illustrate component sub-assemblies and parts of apparatus according to one embodiment of the invention. That apparatus principally is intended for lining of bends by weld deposition, although it readily will be apparent how the apparatus can be adapted for providing linings or treatments of other types. With reference to Figures 1 and 1A, there is shown a bend mounting and rotating sub-assembly 10 of bend modification apparatus. This comprises a drive system and has 10 a variable output motor 12 and, rotatable on a principal horizontal axis X under the action of motor 12, a drive frame 14. Mounted within frame 14, there is a triangular, bend support frame 16, having cradles 18 on which a bend 20 is releaseably mountable by clamps (not shown) . The overall arrange is such that, with bend 20 secured on cradles 18, a chosen radial, circular section of bend 20 is located in a vertical work plane perpendicular to axis X, with that radial section centered on that axis. Thus, with rotation of frames 14, 16 under the action of motor 12, bend 20 is rotated around 20 axis X with the chosen section retained in that relationship. Projecting from frame 14, there is a support plate 11 having a stub axle 13. Plate 11 supports axle 13 so that the latter has its axis substantially co-incident with axis X. Plate 11 and axle 13 are rotatable with frame 14 and their function will become evident in the following. The alternative arrangement of Figures 2 and 2A is operationally the same as that of Figures 1 and 1A and the same reference numerals denote similar parts. However, in this instance, variable speed motor 12 is positioned adjacent 30 plate 15 of frame 14 and rotates frame 14 on axis X by means ET of an output gear assembly 17 drivingly engaging peripheral gear teeth 19 on plate 15. Also, rollers 21 rotatably support frame 14 at peripheral ring 23 to facilitate rotation of the latter. The alternative arrangement of Figures 2 and 2A is to be understood as applicable in all subsequent references to that of Figures 1 and 1A. A weld head 22 is positioned at the work plane. Head 22 is retained in a substantially vertical orientation, for applying weld metal to the bottom of the chosen section of 10 bend 20 as the latter is rotated, to form an annular weld zone around that section. To retain head 20 in that orientation, it is pivotally mounted at one end of a carrier arm 23, comprising a parallelogram linkage arrangement which includes upper and lower arms 24,26, which extends into one end of bend 20. The outer end of arms 24,26 are pivotally connected to rotation means, described below. Support frame 16 is pivotally mounted on frame 14 for movement about an axis through pin 28 which is at right angles to, but spaced laterally from, axis X. That pivot axis 20 also is on the centre of curvature of bend 20 such that, on completion of application of a weld zone around the chosen section of bend 20, frame 16 is pivoted to present a next adjacent radial section of bend 20 in the work plane and a next weld zone is formed therearound. This procedure is followed until at least one half length of bend 20 has been internally lined with weld metal, after which bend 20 may be reversed to line its remaining length. For such pivoting of frame 16, it is provided with rollers 25 which ride on the surface of frame 14. Also, a 30 chain or set of gear teeth 27 are provided around the arcuate F? circumference of frame 16. A motor 29 mounted below frame 14 drives a sprocket 31 engaged with chain or gear teeth 27 via a reduction gear system (not shown); sprocket 31 being mounted on a spindle 35 which projects through frame 14. Motor 29 can provide either step-wise pivoting of frame 16, on completion of each revolution of frame 14 under the action of motor 12, or it can provide continuous pivoting of frame 16 as frame 14 is rotated by motor 12. Such pivoting of frame 16 thus is such that weld head 22 deposits successive annular weld beads 0 or a continuous helical weld bead, respectively; but, in each case, the weld metal deposited most preferably provides continuous cover over at least a portion of the entire inner surface of bend 16. Figure 3 shows a carrier arm rotation sub-assembly 30 of the bend modification apparatus. As indicated in Figures 2 and 3, arms 24,26 extend from sub-assembly 10 to sub-assembly 30, and are inclined at a small angle, such as about 20 , to axis X. As shown in Figures 3 and 3A, sub-assembly 30 comprises rotation means in which the outer 0 ends of arms 24,26 are pivotally connected, and which includes a hub 32, mounted for rotation on axis X, and a pair of radial arm members 34,36 welded to hub 32. Sub-assembly 30 is mounted in relation to frame 14 by hub 32 thereof being retained on stub axle 13. Sub-assembly 30 is rotatable with frame 14, such as by bolts 37 securing flange 39 of axle 13 and arm 34, around hub 32. Figure 3, by its solid line and broken line representations, shows components thereof after rotation of frame 14 (omitted for ease of illustration) and bend 20 after 180° rotation of each. u Each arm 34,36 has a respective plate 38,39 and, at SΓ the outer end of plate 38,39, a respective annular ring 40,41 which has its axis parallel with axis X. Ring 40 of arm 34 is nearer sub-assembly 10 than ring 41 of arm 36, and also has its axis closer to axis X. Within each ring 40,41 there is a spider 42 as shown in Figure 4, and a rectangular yoke assembly 44 in which arms 24,26 are pivotally mounted by means of a gimbal 49 and pins 46. Rollers 45 on spider 42 enable relative rotation between each ring 40,41 and its spider 42. The overall form of sub-assembly 30 is such that, 10; during its synchronous rotation with frames 14,16, arms 24,26 are caused to rotate around axis X in a substantially conical path, within rings 40,41. However, rotation of each ring 40,41 around its spider 42 enables arms 24,26 to be retained in a substantially constant orientation, with arm 24 uppermost. Due to this, the parallelogram linkage relationship between arms 24,26 and a pivotal connection between arms 24,26 and weld head 22, the latter is retained in a substantially fixed orientation. Figure 5 shows a partial view of a preferred form 20 for each spider 42 and the yoke assembly 44 therein. In Figure 5, the arrangement is mechanically the same as that shown in Figure 4, although rollers 45 have not been shown for ease of illustration. Also, it is to be noted that the lower half of the spider and yoke assembly of Figure 5 is essentially a mirror image of that shown in the detailed upper half thereof, as made clear by the components of Figure 5 shown in Figures 6 to 8. As shown in Figure 7, yoke assembly 44 includes a yoke 47 of a generally rectangular, skeletal frame form, with 3Ω; inclined corners. Yoke 47 has a tubular boss 47a. integral FY; with one side thereof. Also, yoke 47 of arm member 36 differs from that of arm 34 as it has a tab 47b projecting outwardly from its side opposite to boss 47a.. Spider 42 has an opening of the same general form as yoke 47, with a recess 42a. receiving boss 47a.. A pivot pin 42b mounted in recess 42a. extends into a bearing within boss 47a. so that yoke 47 is able to pivot about a first axis Y substantially perpendicular to, but laterally offset from, axis X to permit its side opposite boss 47a. to move into and out of the plane of spider 42. Within yoke 47, there is a gimbal 49 which, as shown in Figures 8, is of hollow, elongate rectangular form. A trunnion pin 49a. at each end of gimbal 49 is journalled by a respective bearing 49b in bores 47c. of yoke 47 so that gimbal 49 is able to pivot into and out of the plane of yoke 47 about a second axis Z parallel to the pivot axis Y for yoke 47; axis Z preferably passing through axis X. Weld head carrier arms 24,26, shown in Figure 5, extend through and are pivotally mounted in gimbal 49 by pins 46 such as shown in Figure 4. The axes of pins 46 are substantially perpendicular to the first and second axes Y,Z respectively for yoke 47 and gimbal 49, and substantially perpendicular to axis X. Rollers 45 enable spider 42 and its yoke assembly 44 to remain at a fixed overall orientation such as shown in Figures 4 and 5. Pins 46 enable carrier arms 24,26 to pivot relative to gimbal 49 as they trace out a cone of revolution during rotation of sub-assembly 30 on axis X. However, the freedom of yoke 47 to pivot on axis Y and of gimbal 49 to pivot on axis Z is such that carrier arms 24,26 can be oscillated longitudinally, with corresponding oscillation of the weld head 22. The spider 42 and yoke assembly 44 within ring 40 of arm member 34 is essentially as described so far. The same features are present in the ring 41 of arm member 36, but that ring 41 of arm 36 also includes further components of oscillating means 36a. for imparting oscillating movement to carrier arms 24,26 and weld head 22. The oscillating means 36a. is illustrated in Figures 9, 9A and 10 with components thereof shown in Figures 11 to Q 13. The oscillating means 36a. preferably is mounted on the face of the ring 41, spider 42 and yoke assembly 44 of arm member 36 which is opposed to arm member 34, as depicted in Figure 3. The oscillating means 36a. includes an oscillator mount plate 50, an adjustment collar 51, an oscillating assembly 52 and an oscillation adjustment device 53. Plate 50 and collar 51 each has a central cut out 50a., 51a. the periphery of which allows pivoting of yoke 47 and gimbal 49. Plate 50 is bolted to spider 42 by bolts 51c. extending through holes 50b in plate 50 and engaging in bolt holes 42c. of spider 42. Collar 51 is located between spider 42 and plate 50, with its cut out extending around the bolts retaining plate 50. Bolts (not shown) mounted in bolt holes 51b of collar 51 project through slots 50c. of plate 50 so that collar 51 is capable of limited movement reative to plate 50 in the direction of pivot axes Y,Z. A pivot member 54 (Figure 11) is mounted on collar 51 by bolts (not shown) through holes 51d of collar 51, into bolt holes 54c in the base 54a. of member 5- . When so mounted, stem 54b of pivot member 54 extends through further slot 50d of plate 50 so that mounting bore 54e of member 54 is located on the side of plate 50 remote from collar 51. The clearance provided by slot 50cl for stem 54b also allows movement of collar 51 relative to plate 50. The oscillating assembly 52 is mounted on the face of mount plate 50 remote from collar 51 and includes a circular cam plate 55 having a cam track 55a. formed therein, and a lever system comprising levers 56,57,58. Lever 56 is connected • to bracket 59 on plate 50 so as to be pivotable about fixed axis 56a.. Intermediate its ends, lever 56 has a cam follower provided by the stub of bolt 59 and located in the track 55a., such that rotation of plate 55 under the action of motor 60 causes the end of lever 56 remote from axis 56a. to reciprocate toward and away from plate 50. Lever 57 has a first arm 57a. which defines a slot 57c in which is located the stub of bolt 61 carried at the remote end of lever 56. Lever 57 has a second arm 57b parallel with, but spaced from arm 57a.; with arms 57a. and 57b interconnected by a rod 62 journalled in a sleeve 63 mounted on plate 50. The end of arm 57b remote from rod 62 is pivotally connected, on axis 57d, between one end of two part lever 58 by bolt 64, while the other end of lever 58 is connected by a universal joint 65 to tab 47b of yoke 47. Intermediate its ends, lever 58 is connected to stem 54b. of pivot member 54 by bolt 66 passing through a slot 58b in each part of lever 58 and bore 54c, to enable pivoting of lever 58 on axis 58a.. Axes 56a., 57d. and 58a. are parallel to each other, and to the axis of rod 62. However, those axes are perpendicular to the direction in which collar 51 is movable relative to plate 50; with that direction being parallel to axes Y,Z for yoke 47 and gimbal 49. The arrangement is such that rotation of cam plate 55, to cause pivoting lever 56, results in corresponding pivoting of arms 57a., 57b of lever 57 * an the axis of rod 62, and resultant pivoting of lever 58 on axis 58a.. Such pivoting of levers 56, 57 and 58 is in a reciprocating mode, and causes corresponding oscillating pivoting of yoke 47 on axis Y and of gimbal 49 and, hence, longitudinal reciprocation of weld head support arms 24,26 and weld head 22. The oscillation adjustement device 53 includes a 10 peripheral surface 41a. of ring 41 of arm 36 of sub-assembly 30, which peripheral surface is eccentric with respect to the inner surface of that ring against which rollers 45 rotate. Device 53 also includes rollers 67 mounted on collar 51 and engaging that eccentric surface of ring 41. During rotation of sub-assembly 30, that ring 41 rotates around axis X and relative to its spider 42 and yoke assembly 44. However, as the plate 50 and collar 51 are fixed against rotation relative to that spider 42, the eccentric surface 41a. of ring 41 rotates in engagement with roller 67. Due to its 20 eccentricity, surface 41a causes resultant oscillating movement of collar 51 between the extreme positions defined by slots 50c. and 50d of plate 50 during each rotation of ring 40. That movement of collar 51 causes corresponding oscillating movement of pivot member 54 in slot 50d, with resultant movement of pivot axis 58a. and, hence, of the effective mechanical advantage , of lever 58. The overall consequence of this is that the amplitude of the reciprocation applied to weld head carrier arms 24,26 and, hence, to weld head 22 itself, is progressively varied. 30 In the foregoing, it is indicated that while weld FY head carr er arms , are caused to trace out a cone o revolution, the arms remain in a constant orientation relative to each other. It also is indicated that while rings 40, 41 rotate around axis X, they rotate relative to their spider 42, and pivot assembly therein. However, some form of constraint means is necessary to achieve this constant orientation and relative rotation. In one convenient arrangement depicted in Figure 3, a toothed wheel 36b is co-axially mounted on the spider of arm 36 of sub-assembly 30 at the side of that spider remote from oscillator means 36a.. In such arrangement, a chain 36c passing around wheel 36b and a further such wheel 36d non-rotatably centred on axis X can be used to restrain rotation of the spider and hence retain the arms 24,26 in a constant orientation (such as one above the other) . In such case, the spider wheel orbits around the fixed wheel, without rotation about its own axis. It will be appreciated that a variety of alternative arrangements are possible. Figures 14 and 15 show, in detail, an arrangement for the supply of welding material at the work plane. In this arrangement, the material comprises consumable electrode wire 63 and alloy powder, both received from a respective source thereof, along arms 24,26. Electrode wire is received along conduit 69, from which it issued into guide 70. The latter is of curved form, and guides wire 68 to wire straightening rolls 71. As shown in Figure 16, guide 70 is a V-form in section, and has a series of roller pairs 72,74 which cause wire 68 to follow guide 70. However, in an alternative form for guide 70, it may simply comprise a curved tube through which the wire passes and by which the wire is straightened. From rolls 71, wire 68 passes through boss 76 mounted on arm 26, and though weld head nozzle holder 78 and weld nozzle 80. The lower end of nozzle 80 is spaced from the adjacent surface of bend 20, to leave a short wire stick out. Alloy powder passes from a conduit 82 (Figure 17) to inlet 84 of powder metering device 86; the latter, for example, being of conventional rotary form and operated by a flexible drive (not shown) . Metered powder flow is supplied via pipe 88 from device 86 to nozzle holder 78, and discharged 10 via outlets adjacent nozzle 80. At the end of arms 24,26 remote from weld head 22, then is mounted a powder feeder device 90 and a variable speed drive 92-, shown schematically in Figures 17 and 18 for device 90. A variable drive wire feeder device (not shown) is similarly positioned and may be of any convenient form to pass electrode wire 68 along conduit 69 which extends along upper arm 24, to guide 70. Powder feeder device 90 feeds powder along conduit 82 to metering device 86, conduit 82 also extending along arm 24. At the inlet end of conduit 82, 20 device 90 includes a sleeve 94 reciprocable on that end of conduit 82 under the action of cam 96 and return spring 97. With sleeve 94 urged to the left, from its position shown in Figure 17, powder is able to flow into sleeve 94 from its source, via inlet pipe 98. On snap return of sleeve to the right under the action of spring 97, the powder is left behind, partly due to its inertia, but also because of fixed plunger 99 relative to which sleeve 94 is movable. Finally, it is to be understood that various alterations, modifications and/or additions may be introduced 30 into the constructions and arrangements of parts previously FY described w thout epar ng rom e sp r or am o e invention.

Claims: THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. Apparatus for internal surface modification of pipe bends and elbows (herein referred to as bends), including a support frame; drive means for rotating the frame about a principal axis; the support frame having mounting means adapted to position a bend thereon such that the bend has a radial section thereof positioned substantially in a work plane perpendicular to said axis such that said section is substantially centered on said axis during rotation of the 10 frame about said axis; and a treatment head positionable at said work plane, adjacent said axis, and operable to effect modification of an annular zone of said surface around said radial section as said frame and a bend mounted thereon is rotated under the action of said drive means to move said zone across the treatment head. 2. Apparatus according to claim 1, wherein said mounting means comprises a cradle in which said bend is mountable. 3. Apparatus according to claim 1 or claim 2, wherein 20 said support means is adjustable relative to said support frame to enable each of successive radial sections of said bend to be positioned in said work plane with each successive section substantially centered on said axis. 4. Apparatus according to claim 3, wherein said mounting means is a cradle which is mounted on said support frame and ' adjustable thereon by pivoting about a pivot axis which is at right angles to, but laterally offset from, the principal axis. 5. Apparatus according to claim 4, wherein said cradle 30 is adapted to mount on said support frame a bend of a given FY ra us o curva ure, sa p vo ax s e ng a era y o se from said principal axis by a distance substantially equal to said given radius of curvature and said cradle being adapted to receive said bend thereon such that said bend has its centre of curvature substantially on said pivot axis. 6. Apparatus according to claim 4 or claim 5, wherein said cradle is pivotable on said pivot axis, relative to said support frame, by indexing means operable, on completion of each revolution of said support frame about said principal 10 axis, to position at said work plane a next radial section of said bend. 7. Apparatus according to claim 4 or claim 5, wherein said cradle is pivotable on said pivot axis, relative to said support frame, by adjustment means operable, during each revolution of said support frame about said principal axis, to pivot said cradle in a continuous movement and position at said work plane successive radial sections of said bend. 8. Apparatus according to any one of claims 1 to 7, wherein said treatment head is mounted at one end of the 20 carrier arm; said arm being inclined to said principal axis and, with said treatment head positioned at said work plane, extending through one end of a bend mounted on said mounting means; said carrier arm being supported at at least one location, remote from the one end thereof, by arm rotation means operable to move said arm around said principal axis in unison with rotation of said support frame, such that said arm traverses a cone of revolution at the apex of which said treatment head is mounted. 9. Apparatus according to claim 8, wherein said 30 carrier arm comprises a pair of arm members pivotally secured FT together in a parallelogram linkage arrangement by a plurality of link members such that, during movement of the carrier arm to traverse said cone, said treatment head is retained in a substantially constant orientation. 10. Apparatus according to claim 8 or claim 9, wherein said arm rotation means comprises at least one bracket mounted at one end thereof so as to extend radially of, and rotatable in unison with rotation of said support frame around, said principal axis; said carrier arm being pivotally connected to 0 the other end of said bracket so as to be moved to traverse said cone of revolution during rotation of said bracket. 11. Apparatus according to claim 10, wherein there is a parallel pair of said brackets each mounted on a hub secured to, and rotatable with, said support frame. 12. Apparatus according to claim 10 or claim 11, wherein the at least one bracket has an annular ring at its other end, said ring having an axis laterally offset from said principal axis and having mounted therein pivot means by which said carrier arm is pivotally mounted in relation to said bracket; 0 said pivot means comprising a spider mounted within said ring so as to be rotatable relative to the ring and, within the spider, a coupling arrangement by which the carrier arm is pivotally coupled to the spider so as to be pivotable relative thereto about an adjustement axis perpendicular to said ring axis. 13. Apparatus according to any one of claims 1 to 12, including reciprocating means operable to reciprocate said treatment head parallel to said principal axis to increase the width of said annular zone across which the treatment head is 0 operable to effect modification. y 14. Apparatus according to claim 12, including reciprocating means operable to reciprocate said treatment head parallel to said principal axis to increase the width of said annular zone across which the treatment head is operable tα effect modification; said coupling arrangement including a yoke mounted within said spider and pivotable relative thereto about a first axis, and a gimbal mounted within said yoke and pivotable relative thereto about a second axis; said first and second axis being substantially parallel and offset from each 10 other in a plane substantially parallel to said ring, and each substantially at right angles to both said adjustment axis and said ring axis, such that the carrier arm is longitudinally reciprocable for reciprocating said treatment head under action of said reciprocating means causing pivoting of the yoke on said first axis and pivoting of the gimbal on said second axis. 15. Apparatus according to claim 14, wherein said reciprocating means comprises a rotatable cam member, a cam follower engaged with the cam member and movable in an 20 oscillating path under the action of the cam member, the cam follower being coupled to the yoke member by a lever arrangement through which oscillation of the cam follower causes oscillating pivoting of the yoke on said first axis, with consequential oscillating pivoting of the gimbal on said second axis. 16. Apparatus according to claim 15, wherein reciprocating means is mounted on a first of two plate members mounted on said spider, the second of said plate members having a roller riding on an eccentric peripheral surface of 30 said ring such that, in each revolution of the ring, the FY second plate is caused to move through one cycle of oscillating movement parallel to the ring, relative to the first plate; the second plate carrying a projection providing a pivot for one lever member of the lever arrangement, with said projection being movable with the second plate member and thereby causing variation in the amplitude of oscillation imparted to the carrier arm and treatment head. 17. apparatus according to any one of claims 1 to 16, wherein said treatment head is a weld head, said apparatus 10 further including weld wire supply means for supplying weld wire to said weld head. 18. Apparatus according to any one of claims 8 to 12, wherein said treatment head is a weld head, said apparatus further including * weld wire supply means for supplying weld wire to said weld head; said supply means being located remote from said weld head with there being a conduit extending along said carrier arm by which weld wire passes from said supply means to said weld head. 19. Apparatus according to claim 17, further including 20 powder supply means operable to supply alloy metal powder to a location adjacent said weld head to enable internal facing of a bend by bulk welding. 20. Apparatus according to claim 18, further including powder supply means operable to supply alloy metal powder to a location adjacent said weld head to enable internal facing of a bend by bulk welding; said powder supply means being located remote from said weld head with alloy metal powder passing from said supply means to said location, via a conduit extending along said carrier arm, under the action of a powder 30 feeding device and the control of a powder metering device. FY 21. A process for internal surface modification of pipe bends and elbows (herein referred to as bends), wherein a bend is positioned on mounting means of a support frame rotatable * » about a principal axis; the bend being positioned such that it has a radial section thereof positioned substantially in a work plane perpendicular to said axis and such that said section is substantially centered on said axis during rotation of the frame about said axis; a treatment head being positioned at said work plane, adjacent said axis, and 10 operated to effect modification of an annular zone of said surface around said radial section as said frame and the bend mounted thereon is rotated under the action of drive means to move said zone across the treatment head. 22. A process according to claim 21, wherein said support means is adjusted relative to said support frame such that each of successive radial sections of said bend are positioned in said work plane with each successive section substantially centered on said axis. 23. A process according to claim " 22, wherein said 20 mounting means is a cradle which is mounted on said support frame and is adjusted relative to said support frame so as to pivot about a pivot axis which is at right angles to, but laterally offset from, the principal axis. 24. A process according to claim 23, wherein said cradle is adjusted relative to said support frame so as to pivot about a said pivot axis which is laterally offset from said principal axis by a distance substantially equal to the radius of curvature of said bend, and wherein said bend is positioned on said cradle such that said bend has its centre of curvature 30 substantially on said pivot axis. FY 25. A process according to claim 23 or claim 24, wherein said cradle is pivoted on said pivot axis, relative to said support frame, by being indexed on completion of each revolution of said support frame about said principal axis, to position at said work plane a next radial section of said bend. 26. A process according to claim 23 or claim 24, wherein said cradle is pivoted on said pivot axis, relative to said support frame, by adjustment means by which, during each revolution of said support frame about said principal axis, 10 said cradle is pivoted in a continuous movement and thereby positions at said work plane successive radial sections of said bend. 27. A process according to any one of claims 21 to 26, wherein said treatment head is mounted at one end of a carrier arm inclined to said principal axis; said treatment head being positioned at said work plane by extending said carrier arm through one end of said bend when so positioned; said carrier arm being supported at at least one location, remote from the one end thereof, and rotated to move said arm around said 20 principal axis in unison with rotation of said support frame, such that said arm traverses a cone of revolution at the apex of which said treatment head is mounted. 28. A process according to claim 27, wherein said carrier arm comprises a pair of arm members pivotally secured together in a parallelogram linkage arrangement by a plurality of link members; said treatment head being retained in a substantially constant orientation during movement of the carrier arm to traverse said cone. 29. A process according to any one of claims 21 to 28, 30 wherein said treatment head is reciprocated substantially FY " parallel to said principal axis to increase the width of said annular zone across which the treatment head is operable to effect modification. 30. A process according to claim 27 or claim 28, wherein said treatment head is reciprocated parallel to said principal axis to increase the width of said annular zone across which the treatment head is operable to effect modification; reciprocation of said treatment head being effected by the operating reciprocating means, acting on a coupling arrangement for the carrier arm, by which said arm is longitudinally reciprocated. 31. A process according to claim 29, wherein the action of said reciprocating means is varied during each revolution of the support frame such that the amplitude of oscillation imparted to the carrier arm and treatment head is varied. 32. A process according to any one of claims 21 to 31, wherein said treatment head is a weld head, weld wire being supplied from supply means to said weld head. 33. A process according to claim 32, wherein alloy metal powder is supplied from powder supply means to a location adjacent said weld head for internal facing of said bend by bulk welding. DATED: 28 October 1986 PHILLIPS ORMONDE & FITZPATRICK Attorneys for: VIC ERS AUSTRALIA LIMITED ' - • •j* ' i •",' J^ C' **«-<-.:..

Inventors: SHANNON JAMES WILLIAM, SHANNON, JAMES, WILLIAM
Applicants: VICKERS AUSTRALIA LTD, VICKERS AUSTRALIA LIMITED
Application year: 1986
Main classification: B23K37
IPC codes: B05B13, B23K9, B23K37, B23Q1