Abstract:
The present invention is directed to a system for welding together segments of a pipeline. The system includes an external alignment mechanism for externally supporting and manipulating the orientation of pipe segments in order to align relative segments. The system also includes an internal welding mechanism for applying a weld to an interior face joint of the two abutted pipe segments. The internal welding mechanism including a torch for applying a weld, a laser for tracking the weld profile and guiding an articulating head of the torch, and a camera for visually inspecting the weld after the weld is applied.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority, under 35 U.S.C. §119(a)-(d), to U.S. Provisional application 61/826628, filed May 23, 2013, the contents of which are incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to a system for aligning and connecting two pipe segments together by welding. 
       BACKGROUND OF THE INVENTION 
       [0003]    Conventional internal welders frequently include internal alignment mechanisms that expand radially outward to contact the interior of the pipe. Alignment of the two pipe segments is accomplished from inside when extension members of a central member contact the interior of the pipe relatively close to the pipe segment joint faces on either side of the joint as shown in U.S. Pat. Nos. 3,461,264; 3,009,048; 3,551,636; 3,612,808 and GB 1261814 (which is each incorporated herein by reference in its entirety). In order to weld the joint, the structure of the expander must allow sufficient space to accommodate a rotating torch. It would therefore be advantageous to provide internal alignment that allows sufficient space for a rotating or articulating torch or to align the pipe segments externally so as to eliminate the need for an internal expander which may create significant internal clutter. 
         [0004]    In addition, the conventional process of internal welding usually involves internal or external alignment and an insertion of the internal welder so that torches align with the face joint. In this process it is sometimes difficult to assess the accuracy of positioning of the internal welder in general and the torch in particular. It is even more difficult to assess the accuracy of the position of the torch as the torch traverses the inside of the pipe along its orbital path during welding. It would therefore be advantageous to provide a system of tracking the structure of or positioning of pipe edges at the pipe interface in order to control the torch by use of the tracked condition of the interface. Specifically, it would be advantageous to first track a profile of the interface with a laser before sending a signal to an electronic controller to direct the position and orientation of the welding torch relative to the tracked pipe interface profile. 
         [0005]    Furthermore, conventional pipeline welding systems that employ external alignment mechanisms typically support two segments on rollers and manipulate the position and orientation of the segments until alignment is satisfactory. Whether an alignment is satisfactory typically will depend, for example, on industry acceptable high-low gauges that are fairly accurate but are manually operated and positioned at discrete locations and not over the entire pipe interface. In any case, the profile or structure of the interface as observed from the inside of the pipe is not typically a consideration for quality of alignment. It would therefore be advantageous to provide an alignment system in which information about the interface profile as read by the laser is used as an input parameter during the external alignment process. Specifically, it would be advantageous to provide the information from the torch controlling laser to the controller which would utilize the information in controlling external alignment mechanisms. 
         [0006]    Moreover, conventional pipeline systems for welding pipe segments will typically lack a capability to visually inspect the weld applied by the torch. It therefore would be advantageous to provide a camera that followed the torch weld application and a display for showing an image of the weld in order for an operator to visually inspect the quality of the weld. 
         [0007]    Other advantages of the present disclosure will be apparent by review of this disclosure. Patentable advantages are not limited to those highlighted in this section. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention system for aligning and welding together the faces of two pipe segments includes an external alignment mechanism and a welding mechanism. The external alignment mechanisms may be as sophisticated as the line up modules shown in the drawings or as simple as a tipton clamp as illustrated in U.S. Pat. No. 1,693,064. The mechanisms used may also be suitable for on or off shore pipeline construction. U.S. Pat. No. 1,693,064 is incorporated herein by reference in its entirety. Whatever mechanism is employed, the external alignment mechanism supports and adjustably positions each segment so that the segments are substantially collinear or axially aligned along their longitudinal axes. 
         [0009]    The external alignment mechanism may support a pipe segment and may include powered features that allow the position and orientation of the pipe to be adjusted. Specifically, the external alignment mechanism may include rollers that allow the pipe to move longitudinally. The pipe may also be supported by rollers that allow the pipe to be rolled about the longitudinal axis and moved up and down. The position and orientation adjustments may be automatic as by motor power or hydraulic power controlled at an operator station or fed into a central controller that automatically controls an aligns the segments based on predetermined alignment parameters or feedback from an internal laser reading an interface or joint profile. 
         [0010]    The welding mechanism is preferably an internal welding machine that applies a weld (e.g., a gas metal arc weld “GMAW”) from inside the pipe segments to a face or edge joint of the segment and into a v-shaped opening formed by chamfered edges of the two pipe segments (other cross-sectional shapes other than a V may be used also). The welding mechanism includes a carriage capable of engaging the inner walls of the pipe to secure or lock itself within the pipe in a fixed position and a welding portion rotatably supported from the carriage within the pipe. Specifically, the internal welder is located within the aligned pipe and then positioned longitudinally so that a weld head or torch is in longitudinal proximity to the edge joint. The welding mechanism also includes a rotary mechanism for rotating the welding portion relative to the carriage. The weld head or torch is rotatably supported on the welding portion about the pipe longitudinal axis so that the torch may closely follow the entire interior joint interface in an orbital rotation. Specifically, during welding, the torch of the articulating head follows the edge joint around the entire interior circumference of the pipe applying weld material. In addition to circular rotation relative to the carriage, various control elements may move the weld head axially along the pipe relative to the carriage, radially toward and away from the joint, and pivotally about a point or axis (e.g., an axis parallel or perpendicular to pipe longitudinal axis A-A). A controller may direct the torches pivoting. These degrees of freedom of articulation allow the weld head to be very effective and efficient in filling in interface profiles optimally and where necessary. 
         [0011]    The welding mechanism also includes a laser tracking mechanism that works in conjunction with the torch of the welding portion to sense interface joint profile or/and weld material profile to apply weld material to the edge joint in the appropriate location and amount. The laser mechanism surveys the weld and sends a signal to the controller of the articulating weld head to control movement of the head around the entire edge joint. Specifically, the torch follows the laser as the weld head control system continuously receives weld profile information from the edge joint. The information is then used to continuously adjust the torch to achieve the desired weld structure. 
         [0012]    In addition to the laser tracking mechanism, the system may include a 2D camera for visual inspection of the weld. The 2D camera is mounted on the welding portion and follows the torch so that an operator can inspect the weld as soon as it is created by the torch. A visual signal is delivered to an external operator display. For example, the 2D camera may be a color camera and a change in coloration may indicate a weld defect to the operator. A perceived change in profile may also indicate a defect. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  illustrates a perspective view of a pipe welding system of the present invention showing two externally aligned pipe segments supported on alignment mechanisms. 
           [0014]      FIG. 2  illustrates an enlarged external view of a pipe interface of two segments to be welded using the system of  FIG. 1 . 
           [0015]      FIG. 3  illustrates the system of  FIG. 1  showing a welding mechanism inserted into a segment according to  FIG. 1 . 
           [0016]      FIG. 4  illustrates an enlarged view of a section of  FIG. 3  showing the welding portion of the welding mechanism positioned for welding in a pipe segment according to  FIG. 1 . 
           [0017]      FIG. 5  illustrates a cross-sectional view of  FIG. 4  cut through B-B showing the arrangement of various weld portion elements. 
           [0018]      FIGS. 6 and 7  illustrate side views of the welding mechanism of  FIG. 1 . 
           [0019]      FIG. 8  illustrates a perspective view of the system of  FIG. 1  in a configuration showing a first step of use in which a pipe segment is place on an external alignment mechanism. 
           [0020]      FIG. 9  illustrates a perspective view the system of  FIG. 1  in a configuration showing a step subsequent to  FIG. 8  in which a welding mechanism is inserted into a pipe segment. 
           [0021]      FIG. 10  illustrates a side view of the welding portion of the system of  FIG. 1 . 
           [0022]      FIG. 11  illustrates an enlarged perspective view of a section of the welding portion of the system of  FIG. 1 . 
           [0023]      FIG. 12  illustrates another enlarged perspective view of a section of the welding portion of the system of  FIG. 1 . 
           [0024]      FIG. 13  illustrates an enlarged perspective view of the rotary mechanism of the system of  FIG. 1 . 
       
    
    
       [0025]    Like reference numerals have been used to identify like elements throughout this disclosure. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Referring to  FIGS. 1-3 , the system for welding pipeline segments together is described as follows.  FIG. 1  shows an external alignment mechanism  10 A and  10 B which is capable of supporting, positioning, and repositioning multiple lengths of pipeline. Each mechanism  10 A and  10 B may include supports (e.g., rollers) upon which a length of pipeline may be supported. A longitudinal roller  12  moveably supports pipeline segment  105  such that segment  105  may be repositioned along its longitudinal direction defined by arrow A. In addition, rotational rollers  14  are rotatable about an axis parallel to axis A-A of support segment  105  on either side of segment  105  enabling them to rotate or adjust the angular orientation of segment  105  about axis A-A. External alignment mechanism  10  is able to automatically manipulate multiple segments into various positions and orientations via motors, hydraulics, etc. For example the segments may be raised, lowered, rotated, tilted, pivoted, etc. 
         [0027]    As shown in  FIG. 1 , external alignment mechanisms  10 A and  10 B support multiple segments  105 ,  110  and adjust their position and orientation until segments  105 ,  110  are both aligned such that their longitudinal axes A-A are collinear and one end of each of the segments  105 ,  110  abuts at interface edges. Specifically,  FIG. 2  illustrates an enlarged view of detail  100  of  FIG. 1  in which the edges form a pipe interface  120  (known as a “fit up” joint). 
         [0028]    The pipeline aligning and welding system of the present invention applies a weld to the interior of the interface  120  from inside the fitted up segments  105 ,  110 . To apply a weld to the interior of joint  120 , an internal welding mechanism  300  is rolled into an end of one of the segments  105  as shown in  FIG. 3 . A second segment  110  is then placed on external alignment mechanism  10 B and manipulated until both segments  105 ,  110  are satisfactorily aligned. An external force may then be applied to a reach rod  345  of the internal welding mechanism  300  or the mechanism may include automatic self propulsion means for adjusting its axial position within the aligned segments  105 ,  110 . 
         [0029]    As shown in  FIGS. 4 -7 , welding mechanism  300  includes a carriage  301  and a welding portion  302 . Carriage  301  includes at least one alignment mechanism  340 A,  340 B which may expand radially to engage the interior surface of segments  105  or  110 . This expansion and engagement both secures the axial/longitudinal position of welding mechanism  300  relative to segment  105 ,  110  and aligns or radially centers welding mechanism  300  within segments  105 ,  110 . Carriage  301  also includes a body  311  on which rotating mechanism  335  is supported. Body  311  is comprised of multiple elongated structural support members that extend between alignment mechanism  340 A and  340 B. As discussed below welding portion  302  includes a similar corresponding structure  313 . 
         [0030]    Welding portion  302  is rotatably connected to carriage  301  and extends from an end of carriage  301 . The relative rotation between carriage  301  and welding portion  302  is facilitated by a rotary mechanism  335 . Rotary mechanism  335  is secured to carriage  301  and automatically (via a motor and gears) rotates welding portion  302  relative to carriage  301  about longitudinal axis A. Welding portion  302  may be cantilevered from carriage  301  or may be supported by an additional alignment mechanism  340 C located so that torch  305  is positioned between alignment mechanisms  340 B and  340 C. When alignment mechanism  340 C is provided, welding portion  302  is rotatable relative to and between both alignment mechanisms  340 B and  340 C when alignment mechanisms  340 B and  340 C expand to secure themselves to the interior of a segment. Furthermore, carriage  301  may include a reach rod  345  which can be structured as an elongated extension from carriage  301  which an operator may grasp to insert/push or retract/pull welding mechanism  300  to axially position it within a segment  105 ,  110 . 
         [0031]      FIG. 4  shows an enlarged view of section  200  of  FIG. 3  in which only segment  105  is present and segment  110  is absent. As shown in  FIG. 4 , welding portion  302  includes a welding group  303  which comprises a torch  305 , a laser sensor  310 , and a color camera  320 . Welding portion  302  further has a body  313  on which torch  305 , laser sensor  310 , and color camera  320  are supported. Laser  310  tracks an interior joint of segments  105 ,  110 , and detects an interface profile to be used to position torch  305  in applying a weld to the joint interface. Body  313  extends between alignment mechanism  340 B and  340 C. Section  200  shows welding mechanism  300  located inside segment  105  with torch  305  generally pointed in a radially outward direction and positioned to apply a weld to face joint  120 .  FIG. 5  shows an embodiment of a general schematic cross-sectional view of welding mechanism  300  through section B-B which shows welding group  303  looking in the direction of insertion of welding mechanism  300 .  FIG. 5  also shows a direction D of rotation of welding group  303  when it is rotated by rotary mechanism  335 . Therefore, a welding action on a particular point along weld joint  120  will first be acted on by laser sensor  310  followed by torch  305  and finally by 2D inspection camera  320 . 
         [0032]      FIGS. 10-12  illustrate multiple perspectives of the welding portion  302 .  FIG. 10  shows a wire delivery system  322 . Wire delivery system  322  includes a wire spool storage  323 , an optional wire straightener  325 , and a wire feed mechanism  330  which is automatically controlled to deliver the appropriate amount of wire to torch  305 . As rotary mechanism  335  rotates welding portion  302 , wire is fed to the torch  305  by wire delivery mechanism  322 . 
         [0033]    As mentioned above, torch  305  may be positioned and oriented in multiple ways by multiple mechanisms. Torch  305  is supported on a manipulator. The manipulator includes a radial positioner, an axial positioner and a pivoter. Specifically, a radial positioner  307  (e.g., a rack and pinion) on which torch  305  is supported is capable of moving the torch radially toward and away from the interior surface of segments  105 ,  110 . In other words, towards and away from the interface of segments  105 ,  110  to be welded. In addition, an axial positioner  309  (e.g., a rack and pinion) may move torch  305  axially within segments  105 ,  110 . The manipulator also includes a pivoter  308  that allows the torch to pivot (e.g., about an axis parallel to segment longitudinal axis A-A). Pivotal movement by pivoter  308  may be powered by a motor and gears  306 . For example, the motor may be a stepper motor. 
         [0034]    The torch manipulator may compound the manipulative movements of the above mentioned elements by dependently supporting the elements. For example, body  313  may support the axial positioner which in turn supports the radial positioner which in turn supports the pivoter which in turn supports the torch. Similarly, the axial positioner may be supported by the radial positioner. Furthermore, any order of support may be employed. 
         [0035]    The elements of the manipulator are controlled by a controller which receives as input, a series of signals including a signal from laser  310  and then processes the information before transmitting a signal to at least radial positioner  307 , axial positioner  309 , pivoter  308 , and wire delivery system  322 . Torch  305  is then repositioned and reoriented continuously according to predetermined parameters of the controller based on signals from profile reading laser  310 . 
         [0036]    The operation of the present invention internal welding system will now be described.  FIGS. 1 ,  8  and  9  illustrate the process of positioning and welding segments  105  and  110  together. In operation, one or more of the following lettered steps may be executed so that: a) a pipe segment  105  is placed on alignment device/pipe stand  10 A; b) internal welding machine  300  is then inserted into pipe segment  105 ; c) a second pipe segment  110  is then aligned with pipe segment  105  and welding mechanism  300  is pulled forward by reach rod  345  or automatically driven so that torch  305  generally lines up with faces joint  120  of pipe segments  105 ,  110 ; d) alignment mechanisms  340 A,  340 B (and if necessary  340 C) are then engaged to secure welding mechanism  300  within pipe segments  105 ,  110 ; e) in one embodiment (optional), rotary mechanism  335  rotates weld head  305  to perform an initial scan of interface joint  120  of pipe segments  105 ,  110  by laser sensor device  310  to ensure optimal fit up; f) if required, steps (c), (d) and (e) may be repeated, i.e. pipe segments  105 ,  110  are realigned/rotated and rescanned by laser  310 , to improve “fit up”; g) optionally, internal alignment mechanism  340 C on the rear of the welding mechanism  300  is engaged to hold the axial position of welding mechanism  300  with respect to both pipe sections  105 ,  110 ; h) with welding mechanism  300  secure in pipe segments  105  and  110 , the root weld (first weld) cycle begins so that laser  310  scans pipe interface  120 , torch  305  follows laser  310 , and the output from laser  310  is used to control the position of articulated torch  305 , where the position and orientation of torch  305  with respect to the interface  120  is controlled so as to produce the best quality weld; i) in addition to a signal from laser  310 , thru the arc current monitoring can also be used in directing the torch position; j) after the completion of a 360° weld, weld head  305  is rotated back to an original position; k) the profile (using laser  310 ) and the visual inspections (with 2D color camera  320 ) are performed either in the previous step (j) or on a separate inspection run;  1 ) after inspection, aligning mechanism  340 A-C are released and welding mechanism  300  is pulled or driven forward towards the open end of welded pipe  105 ,  110  and with the nose of welding mechanism  300  exposed, like (b), pipe segment  110  is placed on external alignment mechanism  10 B and advanced to the next joint; m) steps (c) to ( 1 ) are then repeated for the entire production run. 
         [0037]    In one embodiment, a signal from laser sensor  310  is sent to an electronic controller of external alignment mechanism  10  to automatically reposition one or both of segments  105 ,  110  for a more desirable face joint  120  arrangement. Furthermore, the foregoing steps may be executed in the stated order. However, variations in the order are also contemplated. 
         [0038]    In another embodiment, instead of stopping after the first 360° weld, the rotation is continued to lay another weld pass, the laser could be used to inspect &amp; track simultaneously while the trailing 2D color camera continues inspection after the second weld. 
         [0039]    In still another embodiment, instead of welding a complete 360° weld, the weld is performed in two 180° halves with the same start position. This implementation would require either multiple laser sensors for tracking or a mechanism to physically oscillate the laser and/or the torch in order to maintain the tracking sensor&#39;s lead position in both directions of rotation (i.e., rotate the torch and laser so that they switch positions). 
         [0040]    While the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. It is to be understood that terms such as “top”, “bottom”, “front”, “rear”, “side”, “height”, “length”, “width”, “upper”, “lower”, “interior”, “exterior”, and the like as may be used herein, merely describe points of reference and do not limit the present invention to any particular orientation or configuration.