Abstract:
A system for connecting and aligning pieces of a catwalk trough that prevents sagging of the catwalk trough at a connection point between at least two pieces of the catwalk trough by applying a force to the pieces to counteract any separation forces.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. Provisional Patent Application No. 61/780,457, filed Mar. 13, 2013, the contents of which are herein incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Embodiments of the invention generally relate to catwalks for conveying pipe to a drill floor from a lower section of a drilling rig or drill site. Specifically, embodiments of the invention relate to a system for connecting parts of the trough of a catwalk when the trough consists of two or more pieces. 
         [0004]    2. Description of the Related Art 
         [0005]    In a drilling operation or rig work-over operation, whether on a water-based or land-based drilling rig, pipe for the drilling operation, casing, or other tubulars are often stored at or supplied from a level that is lower than the drill floor. Operators typically use a “catwalk” to convey the pipe from the lower level to the drill floor. The pipe is typically mechanically transported (e.g. pushed and/or pulled) in a v-shaped trough, from a level below the rig floor to the rig floor. 
         [0006]    In certain onshore rigs the catwalk can be one-hundred feet long or longer. One of the problems with catwalks of this size is that they cannot easily be moved on or off the rig location, and cannot be transported on public roads unless they are sixty feet long or less. Accordingly, it would be useful to have catwalk troughs that could be divided into two or more pieces so that they could be more easily transported from location to location. 
         [0007]    A potential problem with a two-piece catwalk trough is that the trough would be likely to sag at the point where the two sections are attached as a result of the weight of the tubular at points below the connection point of the two trough pieces. This would create stress on the trough parts at the point where they are connected as well as creating a potentially dangerous situation for workers located near the catwalk and trough. Accordingly, it would be useful to have a system for connecting and aligning a two piece trough so that the trough will not sag as pipe is transported to the drill floor and so that undue stress will not be placed on each part of the trough. 
       SUMMARY OF THE INVENTION 
       [0008]    Embodiments of the invention provide a system for connecting and aligning the pieces of a catwalk trough when the catwalk consists of two or more pieces. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    So that the manner in which the above recited aspects of the invention can be understood in detail, a more particular description of embodiments of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0010]      FIG. 1A  shows an embodiment of the invention in the position in which pipe is loaded onto the catwalk and into the trough or unloaded from the trough. 
           [0011]      FIG. 1B  shows an embodiment of the invention in the position in which the trough is in the process of being raised to the drill floor level. 
           [0012]      FIG. 1C  shows the trough in an elevated position in which pipe is being conveyed to or from the drill floor. 
           [0013]      FIG. 2  shows a wide-view of the two-part trough, in which the connection point between the two parts of the trough is shown. 
           [0014]      FIG. 3  shows a closer view of the two-part trough, in which the connection point between the two parts of the trough is shown. 
           [0015]      FIG. 4  shows an up-close view of the connection point between the two parts of the catwalk trough. 
           [0016]      FIG. 5  is a side view of the connecter pieces for connecting the two parts of the trough in a detached state. 
           [0017]      FIG. 6  is a different view of the connector for the drill floor side trough piece, showing the rectangular hole between the two bosses of the piece through which the boss of the other piece is inserted. 
           [0018]      FIG. 7  is a view of the two connector pieces in their connected position. 
           [0019]      FIG. 8  is another view of the two connector pieces in their connected position. 
           [0020]      FIG. 9  is another view of the two connector pieces in their connected position. 
           [0021]      FIG. 10  is a cross-section side view of the connecter pieces for connecting the two parts of the trough in its connected position within the catwalk interior.  FIG. 10  also shows a cross section of the hydraulic cylinder for preventing sag between the two sections. 
           [0022]      FIG. 11  is a cut-away cross section view of the spring-loaded pistons shown in FIGS.  5  &amp;  7 - 10 . 
       
    
    
     DETAILED DESCRIPTION 
       [0023]      FIGS. 1A  shows trough  2  in its lowered position in catwalk  1  for conveying pipe to a drill floor. Pipe is loaded into trough  2  so that skate  3  may advance pipe from trough piece  2 A toward trough piece  2 B and a drill floor. Trough pieces  2 A and  2 B are connected at connection point  4 . 
         [0024]      FIG. 1B  shows trough  2  in the process of being raised toward a drill floor by leg  5  that is raised by hydraulic cylinders  6 A and  6 B. Skate  3  would be moving pipe along trough  2  through trough piece  2 A and toward trough piece  2 B. Without the embodiments of the invention described herein, trough pieces  2 A and  2 B would tend to sag at connection point  4  when a pipe section is on trough piece  2 A. 
         [0025]      FIG. 1C  shows trough  2  fully raised where trough piece  2 B would be adjacent to a drill floor. Skate  3  advances pipe to the end of trough piece  2 B so that the pipe can be removed from the trough  2  by the crew on the drill floor and moved toward a rotary or into a setback area on the drill floor. 
         [0026]      FIG. 2  is a side view of the two-piece trough  2 . The two pieces  2 A,  2 B could be of different lengths, depending on the overall length of the trough  2  and the needs for transportation of the catwalk and trough parts to or between drilling locations. If needed or desired for convenience or because of the overall length of the trough  2 , the trough  2  could be designed to be comprised of more than two sections. Connection point  4  is the point at which the two sections of trough  2  in the pictured embodiment, lower piece  2 A and upper piece  2 B, meet. 
         [0027]      FIG. 3  is a closer view of one side of connection point  4  for lower trough piece  2 A and upper trough piece  2 B. Hole  7  in the upper trough piece  2 B allows for the insertion and removal of pin  8  from the connector described in  FIGS. 5-10  below.  FIG. 3  also shows pin  12  from connector piece  10  installed in hole  14  in connector piece  11 . 
         [0028]      FIG. 4  is a detailed version of  FIG. 3  which shows the features highlighted in the description of  FIG. 3  above, including pin  8  disposed in hole  7  of the upper trough piece  2 B, and pin  12  disposed in hole  14  of connector piece  11 .  FIG. 4  also shows hole  9 , centered in pin  8 . Hole  9  is threaded and allows for the insertion of a threaded rod that assists with the installation and removal of pin  8 . 
         [0029]      FIG. 5  is a side view of the connector for the two pieces  2 A,  2 B of the trough  2 , consisting of connector pieces  10  and  11 . Pins  12  and  13  fit into holes  14  and  15  respectively to aid in the connection and alignment of connector pieces  10  and  11 . Depressions  50  (illustrated in  FIG. 8 ) in connector piece  11  accommodate the raised bases of pins  12  and  13 . Boss  16  from connector piece  10  slides between bosses  17  and  18  of connector piece  11 . The sliding of boss  16  between bosses  17  and  18  (through slot  24  illustrated in  FIG. 6 ) results in the alignment of hole  19  from boss  16  with hole  20  from boss  17  and hole  21  from boss  18  (further illustrated in  FIG. 6 ). In one embodiment, the diameter of holes  19 - 21  are about 4 inches. Pin  8 , also with a diameter of about 4 inches, can be positioned in holes  19 - 21  to hold connecter pieces  10  and  11  together. Piston assemblies  22 A and  22 B, which are attached to connector piece  10 , contain pistons  23 A and  23 B respectively, which can provide a bias against connector piece  11  when the two connector pieces  10 ,  11  are connected. 
         [0030]      FIG. 6  is a view of connector piece  11  for trough piece  2 B. Slot  24  is rectangular in shape and accommodates the insertion of boss  16  of connector piece  10  between bosses  17  and  18  of connector piece  11 . Holes  14  and  15  of connector piece  11  accommodate the insertion of pins  12  and  13  from connector piece  10 . 
         [0031]      FIG. 7  is a view of connector pieces  10  and  11  in a connected position. Hydraulic adapters  25 A and  25 B provide hydraulic fluid to hydraulic cylinders  22 A and  22 B respectively. 
         [0032]      FIG. 8  is a side view of connector pieces  10  and  11  in a connected position.  FIG. 8  shows depression  50  in connector piece  11  for accommodating the base of pin  12 .  FIG. 9  is another view of connector pieces  10  and  11  in a connected position. 
         [0033]      FIG. 10  is a cross section of the connector pieces  10  and  11  in a position in which trough pieces  2 A and  2 B are connected together. As illustrated, boss  16  of connector piece  10  is disposed between bosses  17 ,  18  of connector piece  11 , and pin  8  is disposed through aligned holes  19 - 21  formed by the bosses  16 - 18 .  FIG. 10  also shows a cross section of hydraulic cylinder  22 A with piston  23 A, which are identical to hydraulic cylinder  22 B and piston  23 B. 
         [0034]    Additional detail of hydraulic cylinder  22 A is shown in  FIG. 11 . Spring  30  is inside cylinder  22 A. A threaded insert  31  with threads  32  engage threads  33  of hydraulic cylinder  22 A. The hydraulic cylinder  22 A in one embodiment also includes ring seals  34  and  35 , wear rings  36  and  37 , and wiper ring  38 . Spring  30  forces piston  23 A of connector piece  10  to apply pressure to the face of connector piece  11  when tubulars are being advanced along trough  2  of catwalk  1  so that trough pieces  2 A and  2 B will not sag at connection point  4 . Without the pressure applied by pistons  23 A and  23 B, when a section of pipe is in trough piece  2 A, trough pieces  2 A and  2 B would tend to sag, separating toward the bottom of connection point  4  and coming together near the top of connection point  4 . By applying pressure to the face of connector piece  11 , pistons  23 A and  23 B substantially eliminate the sagging of trough pieces  2 A and  2 B by counteracting the separation at the lower end of the connection point  4 . 
         [0035]    When the operator desires to disconnect the two pieces  2 A,  2 B of the trough  2 , hydraulic fluid is pumped through hydraulic adapter  25 A, through fluid passage  39 , through any additional fluid passages running approximately perpendicular to fluid passage  39  and into chamber  40 . The fluid pressure acting on piston  23 A compresses spring  30  and causes piston  23 A to stop applying pressure to the face of connector piece  11  as illustrated in  FIG. 11 . The force from piston  23 B is similarly relieved. This causes a slight sag between trough pieces  2 A and  2 B. Pin  8  is removed from holes  19 - 21 . The two trough pieces  2 A and  2 B are separated by removing pins  12  and  13  from holes  14  and  15  at the same time that boss  16  is removed from between bosses  17  and  18 . 
         [0036]    Embodiments of the invention could also be used to connect more than two sections of a catwalk trough. For instance, if a catwalk trough were made from three or more pieces to further aid with transportation of the catwalk from location to location, the embodiments of the invention could be used to connect a middle section of the trough to both a lower and upper section. 
         [0037]    While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.