Abstract:
An apparatus for producing a pipeline includes a plurality of vehicles for straddling a ditch. Al of the vehicles are carried by wide, relatively soft tires for minimizing damage to the soil surface. A first vehicle receives, aligns and maintains sections of pipe in position over a trench while effecting a first weld. Additional welding of the joints between pipe sections is effected in successive vehicles, and the weld joint is inspected and then coated with plastic. Finally, the pipeline is deposited in the trench, and the latter is backfilled by the last vehicle in the train of vehicles.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to a pipe laying apparatus for use in the construction of a pipeline. More specifically, the invention relates to an apparatus for interconnecting and laying sections of pipe in a preformed trench.  
         DISCUSSION OF THE PRIOR ART  
         [0002]    The traditional method of building pipelines involves numerous pieces of heavy equipment requiring a large right-of-way of approximately thirty meters. Following the digging of a trench, sections of pipe are laid along the pipeline right of way beside the trench. The pipe sections are off-loaded and then exposed to the elements including snow, rain, mud and sand or dust storms. The next step is to weld the sections of pipe together and place them on pallets. Welding crews travel down the pipe to join the sections together. During welding, crews, side booms, tents and other machinery must all be moved simultaneously. In effect, one section of pipe is added at a time. The weld joints are inspected, and a procession of tractors equipped with booms are used to lay the pipe in the trench. Once the pipe has been laid, the trench is backfilled, and the pallets are removed.  
           [0003]    Vehicle traffic along the right-of-way, especially by heavy vehicles and/or vehicles with narrow tires or metal tracks leads to significant soil compression or disturbance of the soil surface. In sensitive ecosystems, particularly in the Arctic, minimizing traffic is important in reducing damage to the environment. Peat moss is particularly prone to compression and compaction.  
           [0004]    Examples of equipment for laying pipeline are described in Canadian Patents Nos. 963,276 issued to A. Wagley on Feb. 25, 1975; 1,053,919, issued to A. G. Bifani et al on May 8, 1979; 1,096,645, issued to M. Gibson on Mar. 3, 1981; 1,129,217, issued to O. M. Dahl on Aug. 10, 1982 and 2,066,768, issued to D. W. Jude on Oct. 19, 1999, and U.S. Pat. No. 2,780,376, issued to R. M. Sanders on Feb. 5, 1957; U.S. Pat. No. 3,900,146, issued to O. W. Fowler on Aug. 19, 1975; U.S. Pat. No. 4,051,687, issued to J. W. Ells on Oct. 4, 1977; U.S. Pat. No. 4,116,014, issued to C. R. Satterwhite on Sep. 26, 1978 and U.S. Pat. No. 4,232,982, issued to C. R. Satterwhite on Nov. 11, 1980. While some of the patents deal with various aspects of pipeline construction, it is readily apparent that a need still exists for a pipe laying system which provides solutions to the problems described above.  
         GENERAL DESCRIPTION OF THE INVENTION  
         [0005]    The object of the present invention is to satisfy such needs by providing a relatively simple apparatus, which is designed to have a minimal impact on the environment while reducing the possibility of human error in the laying of pipe.  
           [0006]    Accordingly, the invention relates to an apparatus for producing a pipeline comprising:  
           [0007]    (a) first vehicle means for receiving, aligning effecting a first weld between and maintaining sections of pipe in position over a trench in the ground while traveling over the trench to form a length of pipeline above the trench:  
           [0008]    (b) second vehicle means for slidably receiving the sections of pipe and effecting at least one additional weld to said sections while following said first vehicle means over the trench;  
           [0009]    (c) third vehicle means for slidably receiving the length of pipeline and inspecting welds and inspecting weld joints between the sections while following said first and second vehicle means over the trench;  
           [0010]    (d) fourth vehicle means for covering said welds to complete the length of pipeline while following the first, second and third vehicle means over the trench; and  
           [0011]    (e) fifth vehicle means for slidably receiving the length of pipeline, installing the length of pipeline in the trench and back-filling the trench while following the first, second, third and fourth vehicle means over the trench.  
           [0012]    The invention also provides specific vehicles for effecting the above listed operations, not the least of which is a pipe handling vehicle for storing, loading and aligning sections of pipe at the front end of the apparatus. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The invention is described below in greater detail with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention, and wherein:  
         [0014]    [0014]FIG. 1 is a schematic top view of a pipe laying apparatus in accordance with the invention;  
         [0015]    [0015]FIG. 2 is a schematic side view of a pipe handling vehicle used in the apparatus of FIG. 1;  
         [0016]    [0016]FIG. 3 is a top view of the vehicle of FIG. 2;  
         [0017]    [0017]FIG. 4 is a side view of the vehicle of FIGS. 2 and 3 on a large scale;  
         [0018]    [0018]FIG. 5 is a top view of the vehicle of FIGS. 2 and 3 on a large scale;  
         [0019]    [0019]FIG. 6 is a front view of wheel and steering assemblies used in the vehicle of FIGS.  2  to  5 ;  
         [0020]    [0020]FIG. 7 is a top view of the wheel and steering assemblies of FIG. 6;  
         [0021]    [0021]FIGS. 8 and 9 are front views of one side of a frame used in the vehicle of FIGS.  2  to  5  in upper and lower positions;  
         [0022]    [0022]FIG. 10 is a partly sectioned view of one end of a wheel carriage used in the wheel assembly of FIGS. 6 and 7;  
         [0023]    [0023]FIG. 11 is a front view of a track and carriage used in the wheel and steering assemblies;  
         [0024]    [0024]FIG. 12 is a cross section taken generally along line  12 - 12  of FIG. 11;  
         [0025]    [0025]FIG. 13 is a front view of the carriage of FIGS. 11 and 12;  
         [0026]    [0026]FIGS. 14 and 15 are cross sections taken generally along lines  14 - 14  and  15 - 15 , respectively of FIG. 13;  
         [0027]    [0027]FIG. 16 is a top view of the steering assembly of FIGS. 6 and 7;  
         [0028]    [0028]FIG. 17 is a front view of the steering assembly of FIG. 16;  
         [0029]    [0029]FIG. 18 is an end view of the steering assembly of FIG. 16  
         [0030]    [0030]FIG. 19 is a front view of cradles for receiving pipe sections;  
         [0031]    [0031]FIG. 20 is a front view of a stop used on the cradles of FIG. 19;  
         [0032]    [0032]FIG. 21 is a top view of the cradles of FIG. 19 and pivot arms;  
         [0033]    [0033]FIG. 22 is a front view of the cradles of FIG. 19 and an elevator for lowering pipe sections onto the vehicle  
         [0034]    [0034]FIG. 23 is a top view of a cradle used in the elevator of FIG. 22;  
         [0035]    [0035]FIG. 24 is a front view of the cradle of FIG. 23;  
         [0036]    [0036]FIG. 25 is front view of pipe feed rollers;  
         [0037]    [0037]FIG. 26 is a front view of a pipe manipulating device;  
         [0038]    [0038]FIG. 27 is a top view of the pipe manipulator of FIG. 26 with parts omitted;  
         [0039]    [0039]FIG. 28 is a front view of a pipe rotator used in the vehicle of FIGS.  2  to  5 ;  
         [0040]    [0040]FIG. 29 is a top view of the pipe rotator of FIG. 28;  
         [0041]    [0041]FIG. 30 is a front view of a pipe feed assembly used in the vehicle of FIGS.  2  to  5 ;  
         [0042]    [0042]FIG. 31 is a partly sectioned front view of an arm used in the assembly of FIG. 30; and  
         [0043]    [0043]FIG. 31 is a rear view of the vehicle of FIGS.  2  to  5 . 
     
    
       [0044]    For the sake of simplicity, parts have been omitted from many of the drawings, and the figures are not on the same scale. However, it is believed that the invention will be fully understood from the following.  
       DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0045]    With reference to FIG. 1, the basic elements of a pipe laying apparatus in accordance with the present invention include a plurality of vehicles designed to straddle and travel along an existing trench  1  for joining and laying sections  2  of pipe therein. Preferably the trench digging machine (not shown), which does not form part of this invention, has wide soft tires for minimizing damage to the surface of the ground. A first vehicle  3  receives the pipe sections  2  from a truck (not shown), stores the pipe, loads the pipe sections one at time onto a conveyor and aligns each section  2  with already aligned and or joined pipe sections. The first vehicle  3  also performs the root pass on a butt weld between successive pipe sections. As the vehicles advance, the pipe sections  2  pass through a second vehicle  4  where a fill weld is performed, and then a third vehicle  5  where the cap weld is applied to the butt joint. Successive vehicles  6  to  9  for receiving the pipe sections  2  contain mechanized inspection equipment for performing X-ray or ultrasonic examination of the welds, application of a plastic shrink wrap to the joint area between sections, and laying of the pipe sections into the ground and finally back filling of the trench.  
         [0046]    It will be appreciated that the above described combination of vehicles straddling the trench eliminates the need for a wide right of way. Instead of thirty meters, an approximately twelve meter right of way should suffice.  
         [0047]    Referring to FIGS. 2 and 3, the vehicle  3  for handling the pipe sections  2  includes a skeletal frame  10  supported for movement along the ground by large, wide tires  11 . The wide tires  11  minimize damage to the terrain over which the vehicle travels. For example, the soil compression and compaction mentioned above is minimized. Moreover, wide tires reduce the likelihood of wheel spin which adversely affects the integrity of soil surfaces. A cab  13  housing controls (not shown) separates the frame  10  into front and rear sections  14  and  15 , respectively. The cab  13  also contains welding equipment (not shown) for traveling around the pipe sections  2  where they abut and applying a first or root weld thereto. An extension  17  is cantilevered from the leading end of the front frame section  15  for supporting one end of longer pipe sections  2 . For short pipe sections  2 , the extension  17  can be omitted from the vehicle  3 . The extension  17  is supported by posts  18  and  19  on the frame  10  and on the extension  17 , diagonal braces  20  on the front frame section  15  and diagonal bars  21  pivotally connected to the posts  19  and the extension  17 . Turnbuckles  23  in the bars  21  facilitate leveling of the extension  17 .  
         [0048]    As mentioned above, the frame  10  is supported by tires  11 . The tires  11  are part of wheel assemblies indicated generally at  25 , each of which includes a pair of wheels  26  (FIGS. 2 and 4) supporting opposite sides of the frame  10 . The wheels  26  are driven individually, but are interconnected by a steering assembly  28  (FIGS. 6, 7 and  16  to  18 ) for turning in unison.  
         [0049]    Referring to FIGS.  6  to  9 , each wheel assembly  25  includes a pair of wheels  26  mounted on the free ends of tubular arms  30  defining the stem of generally T-shaped carriages  31 . A hydraulic motor  32  (FIG. 10) and a brake  33  are mounted in the outer free end of each arm  30 , which is closed by a ring  35 , and a plate  36  connected to the ring  35  by bolts  37 . The shaft  39  of the motor  32  is connected to a bearing assembly  40 , which is connected to the hub  41  of the wheel  26  by bolts  43 . The arm  30  is welded to a tubular vertical arm  44  of the carriage  31 , and reinforcing gussets  45  extend between the arms  30  and  44  for strengthening the carriage.  
         [0050]    The gussets  45  are welded to the arms  30  and  44 , and to brackets  47  in the form of flanges on the top and bottom ends of the arm  44 . Additional gussets  48  extend between the brackets  47  for reinforcing the carriage  31 . A steering shaft  50  also extends between the brackets  47 . A pin  51  (FIG. 12) extending between diametrically opposed bushings  52  in the arm  44  of the carriage  31  is rotatable and vertically movable in diametrically opposed, rectangular openings  53  (FIGS. 8, 9 and  12 ) in a tubular track  54 . The track  54  is removably mounted in brackets  56  and  57  on a post  58  having a C-shaped cross section which in turn is welded to a side of the frame  10 . Gussets  59  reinforce the connection between the brackets  56  and  57  and the post  58 .  
         [0051]    A hydraulic cylinder  61  (FIG. 11) is pivotally mounted on a pin  62  near the top end of the track  54 . The bottom end of a piston rod  63  extending downwardly form the cylinder  61  is connected to a sleeve  64  (FIGS. 11 and 12) on the pin  51  for moving the carriage  31  vertically on the track  54 . As shown in FIGS. 8 and 9, such movement of the carriage  31  results in corresponding movement of the frame  10  to change the clearance between the bottom of the frame  10  and the ground. The pin  51  extending through the openings  53  in the track  54  limits vertical movement of the carriage  31  on the track  54 .  
         [0052]    Steering of the apparatus is effected by the steering assembly indicated generally at  28  in FIGS. 8 and 8. Referring to FIGS.  16  to  18 , the steering assembly  28  includes a frame defined by posts  66  on the sides of the frame  10 , and a crossbar  67  extending between the posts  66 . A tubular spacer  69 , with beveled top and bottom ends, is connected to the post  66  and carries a pair of brackets  70 . Plastic plates  72  on the brackets  70  slidably support a rod  73 , the outer end of which receives a rod  74 , which forms part of a tie assembly  75 . The tie assembly  75  includes a two-part block  77  containing a bushing (not shown) for slidably and rotatably receiving the steering shaft  50  on the carriage  31 , whereby longitudinal movement of the rod  73  results in turning of the carriage  31  and consequently the wheel attached thereto. The inner ends of the rods  73  are connected to opposite ends of a rectangular frame  78 . A pin  79  extending through crossbars  80  on the frame  78  connects the latter to a sleeve  81  on the outer free end of a piston rod  81 . The piston rod  81  extends out of a cylinder  83 , the closed end of which is pivotally connected to a bracket defined by plates  84  extending outwardly from the crossbar  67 . Extension or retraction of the piston rod  81  results in rotation of the carriages  31  at each end of the steering assembly, and consequently turning of the wheels.  
         [0053]    The pipe sections  2  are unloaded from a truck (not shown) onto cradles  100  and  101  on the front frame section  14 . The cradles  100  are defined by inclined arms  102  on the top of the extension  17  each of which receives pipe sections  2 , i.e. the pipe sections are loaded onto both side of the front fame section  14  and the extension  17 . Each cradle  101  includes a pair of inclined arms  105 , inner posts  106  connected to the frame  10 , and stop posts  107  at the outer end of each arm  105 . Diagonal braces  109  extend between the bottom of the post  106  and the arms  105 .  
         [0054]    Retractable stops indicated generally at  110  retain the pipe sections  2  on the cradles  101  and ensure feed of the pipe sections one at a time to a conveyor defined by roller assemblies  111  (FIG. 19). As best shown in FIG. 20, each stop  110  includes an elongated casing  112  of C-shaped cross section. The bottom end of a hydraulic cylinder  113  is pivotally mounted on a pin  114  extending between the sides of the bracket  112 . A piston rod  115  extending out of the top of the cylinder  113  carries a cylindrical bar  116 , which is slidable in a sleeve  118  mounted in the top end of the bracket  112  using plates  119 . When the bars  116  are extended (FIG. 19) they prevent downward and inward movement of the pipe sections  2  on the cradles  101 . When loading a pipe section  2  onto the roller assembles  111  one set of innermost stop bars  116 , i.e the innermost stop bars  116  on one side of the front frame  10  are retracted and a pipe section  2  rolls onto opposed pivot arms  120  (FIG. 21). Once the pipe section has rolled onto the arms  120 , the innermost stop bars  116  are again extended, and the second or outer stop bars are retracted to permit a fresh pipe section to roll into position adjacent to the pivot arms  120 . While only one set of pivot arms  120  are shown in FIG. 5, it will be appreciated that additional pivot arms will be present on the front frame section  14  and/or the extension  17  for receiving each pipe section  2  at spaced apart locations.  
         [0055]    With reference to FIGS. 21 and 22, the pivot arms  120  are pivotally connected by pins  121  to brackets  123  on the sides of the frame  10 . Each pivot arm includes a pair of sides  124  interconnected by crossbars  125 . A pair of rollers  127  extend between the sides  124  on either side of the middle thereof. The pivot arms  120  are retained in the elevated or raised positions shown in phantom outline in FIG. 22 by a cradle  130 , which defines the top of an elevator for lowering the pipe sections  2  onto the conveyor defined by the roller assemblies  111 . Piston rods  131  extending out of hydraulic cylinders  132  are connected to crossbars  133  extending between the sides  134  of the cradle near the ends  135  thereof. The cylinders  132  are pivotally connected to the bottom of the frame  10  by pins  136 . The cradle  130  is guided for vertical movement on the cradle posts  106  by fingers  137  on the ends  135  of the cradle. The cradle  130  moves vertically between a raised position shown in phantom outline in FIG. 22 and a lower position shown in solid outline in FIG. 22.  
         [0056]    As the cradle  130  is lowered, the pivot arms  120  follow the cradle until the space between the free ends of the arms  120  is sufficiently large that the pipe section  2  drops onto and is supported by a rubber pad  139  (FIG. 24) only. The cradle  130  continues to move downwardly until the pipe section  2  rests on the roller assemblies  111 .  
         [0057]    As mentioned above, the vehicle  3  is designed for handling pipe sections  2 , i.e. loading, manipulating and feeding pipe sections rearwardly to already assembled pipeline. Actually, once the pipe sections  2  abut with existing pipeline and are welded in the cab  13 , the vehicle  3  moves forwardly while the pipe sections  2  remain stationary. The pipe sections  2  are received and carried by a plurality of the V-shaped roller assemblies indicated generally at  111  (FIGS. 2 and 3) between the sides of the frame  10 , and the extension  17 . Each roller assembly  111  (FIGS. 19 and 25) includes a pair of inclined, corrugated rollers  141 . Shafts  142  extending out of the bottom ends of the rollers  141  are mounted in plates  143  on the top ends of posts  145 , which extend upwardly from a longitudinally extending supporting bar  146  on the bottom center of the frame  10  and extension  17 . Shafts  147  on the top ends of the rollers  141  are mounted in plates  148  on generally triangular frames  150  at the top of each side of the frame  10  and extension  17 . The V-shaped roller assembly  111  is adapted to support and feed pipe sections  2  having a large variety of diameters.  
         [0058]    Once in position on the roller assemblies  111 , the orientation of the pipe section  2  is adjusted. The pipe section  2  is moved vertically and laterally of the frame by adjustment mechanisms indicated generally at  152  (FIGS. 5, 26 and  27 ). Each adjustment mechanism  152  includes a shallow V-shaped cradle  153  with pads  154  on the top thereof for receiving a pipe section  2 . The cradle  153  is connected to the top end of a rectangular cross section tube  155  by a pin  156 . The tube  155  is slidably mounted in a sleeve  158 . The bottom end of the sleeve  158  is pivotally connected by a pin  160  to a pair of crossbars  161  extending between the sides of the frame  10  at the bottom of the adjustment mechanism  152 . The tube  155  and consequently the cradle  153  are moved vertically by a hydraulic cylinder  163 , the bottom end of which is connected to the sleeve  158  by the pin  160 . A piston rod  164  extends upwardly from the cylinder  163  and is connected to the top end of the tube  155  by the pin  156 . Rotation of the sleeve  158  around the axis of the pin  160  is limited by bars  166  extending between the crossbars  161 . The sleeve  158  and consequently the cradle  153  and any pipe section  2  thereon is moved laterally of the frame  10  by a hydraulic cylinder  168 , the closed end of which is pivotally connected to a post  169  on one side of the frame  10  by a bracket  170 . A piston rod  171  extending out of the inner end of the cylinder  168  is pivotally connected to the sleeve  158  by a clevis  172 .  
         [0059]    Many pipeline producers want the longitudinal seam (not shown) on each pipe section  2  on the top center of the pipeline. For such purpose a pipe rotator indicated generally at  175  is provided on the frame  10 . The rotator  175  includes a pair of parallel arms  176  and crossbars  177  defining a frame, one end of which is pivotally connected to one side of the frame  10  by a pin  179  (FIG. 28). A pair of wheels  180  are mounted in bearings  181  in the arms  172 . One of the wheels  180  is rotated by a reversible motor  183  (FIG. 29) mounted on one of the arms  176 . The wheels  180  are brought into contact with a pipe section  24  by a hydraulic cylinder  184 , the closed bottom end of which is pivotally connected to the other side of the frame  10  by a clevis  186 . A piston rod  187  extending out of the top of the cylinder  184  is pivotally connected to bushings  188  on the free end  189  of the arms  176  by a pin  191 . When the cylinder  184  is actuated to raise the wheels  180  into contact with a pipe section  2 , the motor  183  is started to rotate the pipe section  2  until the longitudinal seam thereon is on top and aligned with the seams on already interconnected pipe sections.  
         [0060]    Once a pipe section  2  has been properly aligned with pipe sections previously fed into the apparatus, the new pipe section  2  must be fed longitudinally into abutment with the existing pipeline. Such feeding is effected using pull wheels  195  (FIG. 30) mounted on the free ends  196  (FIG. 31) of a pair of opposed arms  198 , which are pivotally mounted on the sides of the frame  10 . The wheels  195  are rotated by hydraulic motor  200  (one shown in FIG. 31) mounted on the arms  198 , the shafts  201  of the motors  200  being connected to the pull wheel hubs  202 . The wheels  195  are raised to contact the pipe sections  2  by hydraulic cylinders  204  pivotally connected to the frame  10  by devises  205 , and piston rods  206  pivotally connected to brackets  207  on the arms  198 .  
         [0061]    Pipe sections  2  abutting existing interconnected pipe sections enter the cab  13  as the vehicle  3  advances. In the cab  13 , a welding device (not shown) applies a root weld to butt join the front pipe sections  2  to the pipeline. The pipeline then passes through curtains  210  (FIG. 32) at the back of the cab  18 . The rear frame section  15  also carries hydraulic tanks  211  (FIGS. 2, 3 and  5 ) a diesel generator  212  and a main diesel engine  214 . A fresh pipe section  2  is placed in the frame  10  and the process described above is repeated.