Abstract:
A line-up clamp unit is powered by a diesel engine which drives a hydraulic pump for operating hydraulic equipment in the unit. The unit includes a line-up clamp which has front shoes, rear shoes and expanding copper back-up tiles. Drive wheels are deployed by a hydraulic cylinder and operated by a hydraulic drive motor. A group of aligning assemblies are electrically operated and fiction to extend L-shaped members to beyond the diameter of the pipe being welded so that the unit can be automatically positioned at the end of a pipe section. A control box includes a radio receiver for receiving control signals and producing corresponding electric control commands for operating the line-tip unit. A remote control radio transmitter has operating, mechanisms, including push buttons and toggle switches, for operating the line-up unit, including the engine, drive motor, brakes, line-up clamp and aligners.

Description:
TECHNICAL FIELD OF THE INVENTION 
   The present invention pertains in general to the welding of pipe for use as pipelines and in particular to the alignment of pipe ends for welding. 
   BACKGROUND OF THE INVENTION 
   Pipelines, which extend for many miles, are constructed by welding together sections of pipe. The welding together of the pipe ends is a major aspect in the cost and time required for the construction of the pipeline. In order for welding equipment to be applied to weld the pipe sections, the ends of the pipes must be accurately aligned with each other and held rigidly in position where the welding takes place. One way of holding the pipe sections in position is by use of an internal line-up clamp. Internal line-up clamps are shown in U.S. Pat. No. 5,356,067 and U.S. Pat. No. 5,535,938. A self-powered internal line-up clamp and internal welding apparatus is described in U.S. Pat. No. 5,059,765. These line-up clamps require the use of a reach rod or tether line for moving and positioning the line-up clamp at the abutting ends of the pipe sections and this rod or line must be passed through each new pipe section. 
   A bending mandrel is a device that is positioned within a section of pipe so that the pipe section can be subjected to outside forces and bent to a desired configuration. The mandrel prevents the pipe wall from collapsing during the bending process and producing an uneven or distorted pipeline wall. Such a pipeline mandrel that includes an apparatus for remote control positioning is shown in U.S. Pat. No. 6,092,406. A positioning apparatus for use with pipeline equipment is shown in U.S. Pat. No. 5,651,638. It has heretofore been known to use a diesel engine mounted to a pipe mandrel for providing motive and other operational power to the mandrel. 
   Due to the substantial time and effort required to move and then accurately position an internal line-up clamp, there exists a need for a line-up clamp unit that is self-powered so that it can be moved through pipeline segments and then be positioned accurately without the need to repeatedly position a rod or tether line that is used for controlling and moving the clamp unit. 
   SUMMARY OF THE INVENTION 
   One embodiment of the present invention is an internal line-up clamp unit which is used for the welding of pipe sections in the building of a pipeline. The unit includes a frame with an internal combustion engine mounted to the frame. A hydraulic pump is connected to be driven by the engine. A group of solenoid hydraulic valves are connected to the hydraulic pump. A set of wheels are mounted to the frame for supporting the unit when the unit is positioned inside a pipe. A hydraulic drive motor is connected to be operated by one of the solenoid valves. At least one drive wheel is mounted to the frame and connected to be driven by the hydraulic drive motor under control of a solenoid valve. A hydraulic actuator is connected to extend and retract the drive wheels, is hydraulically connected to the hydraulic pump and is controlled by a solenoid valve. A brake mechanism including a hydraulic actuator is connected to the hydraulic pump and controlled by a solenoid valve. A line-up clamp is provided as a part of the unit and includes a set of extendable front shoes, a set of extendable back shoes and a set of extendable back-up plates, the line-up clamp including a hydraulic actuator connected to a solenoid for extending and retracting the front shoes and back-up tiles and a hydraulic actuator connected to a solenoid for extending and retracting the rear shoes. A portable, remote control radio transceiver has control mechanisms, such as buttons and switches, for operating the engine, the drive motor, the drive wheel actuator, the brake mechanism, the front shoes and the back-up plates and the rear shoes. The remote control transceiver transmits control signals in response to actuation of the control mechanisms. A control box is mounted to the clamp unit and has a radio transceiver that receives the control signals from the remote control radio transceiver. In response to the control signals, the control box produces electrical control signals for operating the solenoids for the hydraulic actuators. 
   A further aspect is an aligner assembly mounted adjacent the line-up clamp and having one or more actuators for extending and retracting a plurality of alignment members. The aligner assembly is controlled by the remote control transceiver and the control box. 
   A still further aspect is the inclusion of detectors or switches for determining the position of moveable components in the line-up control unit and indicating these positions at the remote control transceiver. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, reference is now made to the following detailed description taken in conjunction with the drawings in which: 
       FIG. 1  is an elevation view of a line-up unit in accordance with the present invention, 
       FIG. 2  is a schematic illustration of operative components of the line-up unit and the interconnection of these components, 
       FIG. 3  is a front view of a line-up unit control box in accordance with the present invention, 
       FIG. 4  is a front view of a line-up unit remote control box in accordance with the present invention, and 
       FIG. 5  is an illustration of the line-up unit of the present invention positioned in pipe sections for providing pipe alignment and welding backup. 
   

   DETAILED DESCRIPTION 
   A tetherless line-up clamp unit  20  in accordance with the present invention is shown in FIG.  1 . The line-up unit  20  is powered by an engine  22 , which is preferably a diesel engine. The engine  22  includes a radiator  24  having a fan which produces an air flow in the direction of arrow  26 . The engine  22  powers a hydraulic pump (shown in  FIG. 2 ) which is positioned within a housing  28 . A battery  30  provides electrical power for the line-up unit  20  as well as a source of starting energy for the engine  22 . Engine  22  includes an alternator for charging the battery  30 . The unit  20  has a frame that supports the various components of the unit  20 . Engine  22  is mounted to the frame of unit  20 . 
   The line-up unit  20  is provided with an extendable brake  36  which can engage the interior of a pipe to hold the unit  20  in a fixed location. The unit  20  further includes a set of drive wheels  38  which are operated by a hydraulic drive motor (shown in FIG.  2 ), for moving the unit  20  within a section of pipe. The unit  20  is lifted and transported by means of a lifting hook  40  that is attached to the frame of the unit  20 . The unit  20  is supported within a pipe section by wheels  42 ,  44  and  46 . Wheels  42  and  46  provide the primary support. A corresponding set of three wheels (not shown) are located on the far side of the unit  20  illustrated in FIG.  1 . 
   The line-up unit  20  includes a line-up clamp  48  that includes rear shoes  50  and front shoes  52 . The clamp  48  further includes extendable back-up tiles  54  which can be made of various materials, for example, copper. A line-up clamp applicable for use with the present invention is described in U.S. Pat. No. 5,535,938 entitled “Internal Line Up Clamp” which issued Jul. 16, 1996. This patent (U.S. Pat. No. 5,535,938) is incorporated herein by reference. The line-up clamp  48  includes a first hydraulic actuator for positioning the rear shoes  50  (extended or retracted) and a second hydraulic actuator for simultaneously positioning (extended or retracted) the front shoes  52  and tiles  54 . These two actuators are located within the clamp  48 . 
   The line-up unit  20  is further provided with a nose cone  56  which is a part of the frame. The nose cone  56  comprises a plurality of tubular members which extend forward of the line-up clamp  48  and meet at a common support junction  58 . 
   An electric actuator  64  is mounted on the interior of the nose cone  56  and includes a movable rod  66  that is connected to an aligner  68 , which includes an L-shaped member  68   a  and parallel rods  68   b  and  68   c  which are pivotally connected to the member  68   a  at one end and to a fixed frame member at the opposite end. The member  68   a  moves along an arc as limited by the rods  68   b  and  68   c . The rod  66  drives the aligner  68  to extend the member  68   a  radially outward and to retract the member  68   a  to an inward, storage position. The rods  68   b  and  68   c  pivot about the fixed ends thereof. The movable member  68   a  extends radially outward for engaging the end of a section of pipe when the unit  20  is moved back into a pipe section. 
   An electric actuator  70  includes a moveable rod  72  that is connected to an aligner  74  which likewise has an L-shaped member  74   a  and parallel rods  74   b  and  74   c  that are pivotally connected at one end thereof to the member  74   a  and to a fixed frame at the opposite ends. Aligner  74  operates in the same manner as the aligner  68  described above. There is a third aligner and related electric actuator (not shown) so that the total of three aligners are located at 120° positions along the periphery of the unit  20 . Although an electric drive assembly is described for operating the aligners, a hydraulic drive could alternatively be used with corresponding solenoids for control of the drives. The aligners  68  and  74  can be set to different lateral positions (along the lengthwise dimension of the pipe) to thereby position the back-up tiles at different lateral positions under the junction of the pipes for the purpose of evening the wear on the tiles. The aligners can improve the welding process, but are not a necessary part of the present invention. 
   The line-up unit  20  further includes a control box  76  which is connected via a multi-line cable  78  to control solenoid valves in the unit  20  and through other cables to the aligner actuators  64  and  70 . The control box  76  is a transceiver, that is, it includes a transmitter and a receiver. 
   A pair of “whisker” rods  79  are connected to respective switches mounted to the nose cone  56  for indicating when the nose cone  56  has extended through the open end of a pipe section. The rods  79  swing downward when the nose cone  56  exits from a pipe section. 
   Referring to  FIG. 2 , there is shown a group of operative components which are used in conjunction with the present invention and the specific interconnection of these components. The engine  22  of the unit  20  is connected to drive a hydraulic pump  80  which is mounted within the housing  28 . The pump  80  drives hydraulic fluid through lines  82  to a manifold  84 . A set of solenoid valves  86 ,  88 ,  90 ,  92  and  94  are mounted on the manifold  84 . Cable  78  is provided with five sets of electrical lines that are connected respectively to the solenoid valves  86 ,  88 ,  90 ,  92  and  94 . The cable  78  is routed through the line-up clamp  48 . 
   The solenoid valve  86  is connected to hydraulic lines  98  which are connected to the hydraulic actuator for the front shoes  52  and back-up tiles  54 . The solenoid valve  88  is connected through hydraulic lines  100  to the hydraulic actuator for operating the rear shoes  50 . The solenoid valve  90  is connected through hydraulic lines  102  to a hydraulic cylinder  104  which functions to extend and retract the drive wheels  38 . Solenoid valve  92  is connected through hydraulic lines  106  to a hydraulic cylinder  108  that operates the brake  36  of the line-up unit  20 . Solenoid valve  94  is connected through hydraulic lines  110  to a hydraulic drive motor  112  that powers the drive wheels  38  of the line-up unit  20 . 
   The actuators  64  and  70  together with a third drive assembly  71  are connected through respective electric cables to the control box  76 . 
   The control box  76 , which is connected to the cable  78 , is mounted on the nose cone  56  to permit an operator to manually control the line-up unit  20  when the operator is in close proximity to the line-up unit  20 . The control box  76  includes a radio transceiver that has an antenna  120 . A remote control  122  includes a transceiver with an antenna  124  and this unit permits an operator to move and control the line-up unit  20  from a remote location by transmitting commands from the remote control  122  to the control box  76  by radio signals. The control box  76  is described in further detail in FIG.  3  and the remote control  122  is described in further detail in FIG.  4 . The remote control  122  and control box  76  utilize transceivers (transmitters and receivers) so that commands can be sent from the remote control  122  to the control box  76  for operating the various components of the unit  20 . Many of these components include corresponding sensors or detectors to determine when a particular commanded operation has been performed. This information is conveyed to the control box  76  and is then transmitted back to the remote control  122  for activating specific lights to indicate when particular operations have actually been accomplished. This is further described in reference to FIG.  4 . This feedback of information allows the operator, at a remote location, to know when a commanded operation has been performed. This not only enhances the operational capabilities of the unit  20 , but provides substantial safety because the operator knows when a commanded action has been completed. 
   The control box  76  is coupled by a cable  77  to the engine  22  for starting and stopping the engine  22 . 
   The transceivers in the control box  76  and the remote control  122  can communicate directly with each other or optionally can be configured to communicate through a transponder  126 . The control box  76  will be located within a section of pipe and it may be necessary for the remote control unit  122  to be positioned at some point away from the pipe, such as due to adverse terrain or weather conditions. The transponder  126  can be positioned at the open end of a pipe section such that it has essentially line-of-sight bi-directional transmission paths to both the control box  76  and the remote control  122 . The transponder  126  can be located in any position where it can communicate with both the control box  76  and the remote control  122 . The reliability and consistency of communication between the remote control  122  and control box  76  can be improved by use of the transponder  126 . 
   In order to indicate to an operator using the remote control unit  122  when a commanded operation has actually been completed, the unit  20  is provided with proximity detectors or switches for indicating particular positions of components which can be moved from one position to another. Such detectors or switches can be, for example, physical contact switches, magnetic switches or Hall effect sensors. Hydraulic cylinder  108  has associated with it proximity switches  117   a  and  117   b . Proximity switch  117   a  is activated when the brake  36  is in the retracted position and switch  117   b  is activated when the brake  36  is in the extended position. Switches  117   a  and  117   b  are connected to the control box  76 . The hydraulic cylinder  104  functions to extend and retract the drive wheels  38 . A proximity switch  119   a  indicates when the drive wheels are in the retracted position and a proximity switch  119   b  is activated when the drive wheels are in the extended position. These switches are electrically connected to the control box  76 . 
   Proximity switches  121   a  and  121   b  are used to indicate respectively when the rear shoes  50  are in the retracted and extended positions. Proximity switches  123   a  and  123   b  indicate respectively when the front shoes  52  and the back-up tiles  54  are in the retracted and extended positions. 
   The whisker rods  79  are connected to or mounted near respective proximity switches  115   a  and  115   b  which are activated when the rods are essentially in the vertical position. 
   The actuator  64 , which operates an aligner assembly, works in conjunction with proximity switches  125   a  and  125   b  to indicate respectively when the aligner is retracted and extended. Actuator  70  works in conjunction with proximity switches  127   a  and  127   b  to indicate when the corresponding aligner is in the retracted and extended positions. 
   The third actuator  71  and aligner have corresponding proximity switches  129   a  and  129   b  to indicate respectively when the actuator and aligner are in the retracted and extended positions. In place of the proximity switches, the component positions can be determined by measuring pressure in hydraulic lines. 
   The control box  76  is shown in FIG.  3 . The control box  76  is activated by a power switch  130 . The brake  36  of the line-up unit  20  is operated by a toggle switch  132 . When the brake switch is in the “OFF” position, the line-up unit  20  can be moved through the pipe, but when the brake switch is in the “ON” position, the line-up unit  20  is held in a fixed position by the brake. Toggle switch  134  has a neutral center position, but when pressed toward the left (the forward position), moves the line-up unit  20  forward in the pipe, toward the opening, and when pressed to the reverse position, causes the line-up unit  20  to move backward through the pipe. The diesel engine  22  is activated by pressing a start button  136  and deactivated by pressing a stop button  138 . 
   The drive wheels  38  are moved outward to engage the interior of the pipe surface when button  140  is pressed and are moved away from the pipe interior surface to a retracted, non-engaged position when button  142  is pressed. The aligner members  68   a  and  74   a , and a corresponding third member, are extended radially outward when switch  144  is set to the “UP” position and these members are retracted when the toggle switch  144  is set to the “DOWN” position The rear shoes  50  are engaged to the interior of the pipe when a switch  146  is set to the “UP” position and are moved out of engagement with the interior surface of the pipe when the switch  146  is set to the “DOWN” position. The front shoes  52  are engaged with the interior of the pipe when a switch  148  is set to the “UP” position and are moved away from, that is retracted, when the switch  148  is set to the “DOWN” position. 
   The electrical system voltage for the line-up unit  20  is measured by a voltmeter  150 . 
   The remote control  122  is further described in reference to FIG.  4 . When the remote control  122  is in use, it provides substantially the same operational capabilities that are provided by the control box  76 . The remote control  122  includes a set of indicator lights (a visual display) for showing the actual position of moveable components of the unit  20 . The diesel engine  22  is started by depressing a “START” button  158  and is stopped by pressing a “STOP” button  160 . The brake  36  is operated by a command produced by a toggle switch  162 . When the toggle switch  162  is set to the “OUT” position, a command is sent from the remote control  122  to the control box  76  which produces a signal for operating the solenoid to engage the brake. If the brake shoes are correctly engaged to the interior surface of the pipe, a light  64  is turned on. When the switch  162  is set to the “IN” position, a command is transmitted to retract the brake and if this is done, a light  166  is activated to indicate that the brakes have been retracted. The lights  164  and  166  are activated respectively in response to the proximity switches  117   b  and  117   a  which respond to the position of the brake  36 . 
   The drive wheels  38  are engaged to the interior surface of the pipe when a toggle switch  168  is positioned to the “OUT” position and at the same time a light  170  is activated by switch  119   b  to indicate that the drive wheels are engaged. When the switch  168  is moved to the “IN” position, the drive wheels  38  are retracted and this condition is indicated by a light  172  which responds to switch  119   a.    
   The aligner members  68   a  and  74   a  (see  FIG. 1 ) are driven to the extended position when the toggle switch  174  is set to the “UP” position and a light  176  is turned on by switches  125   b ,  127   b  and  129   b . When the toggle switch  174  is set to the “DOWN” position, the aligners are retracted and a light  178  is turned on by switches  125   a ,  127   a  and  129   a.    
   The rear shoes  50  are driven into engagement with the interior of the pipe section when a toggle switch  180  is placed in the “UP” position. When this occurs, a light  182  is activated by switch  121   b . When switch  180  is set to the “DOWN” position, the rear shoes are retracted and a light  184  is turned on by switch  121   a . The front shoes  52  and back-up tiles  54  are engaged with the interior of the pipe section when a switch  186  is moved to the “UP” position and this results in the operation of the light  188  by switch  123   b . When switch  186  is set to the “DOWN” position, the front shoes and backup tiles are retracted and a light  190  is turned on by switch  123   a.    
   The line-up unit  20  is commanded to automatically travel and detect the end of the pipe by pressing a button  200 . This automatic travel state is indicated to be in operation when a light  202  is activated. The toggle switch  204  is used to manually position the line-up unit  20  within pipe. When the switch  204  is moved to the forward (FWD) position, the line-up unit  20  moves forward in the pipe, which is toward the next pipe section to be welded to the pipeline. When the toggle switch  204  is moved to the reverse (REV) position, the line-up unit  20  moves in the direction of arrow  26  away from the opening of the pipe. 
   Conventional and well known radio remote control transmitters and receivers can be used in the present invention. One radio remote control which can be utilized in the present invention is shown in U.S. Pat. No. 6,092,406 which describes a pipe mandrel that is moved to specific locations in a pipe before the pipe is bent to a required shape. U.S. Pat. No. 6,092,406, which is entitled “PIPELINE MANDREL POSITIONING CONTROL SYSTEM” and which issued Jul. 25, 2000 is incorporated herein by reference. A further radio transmission and receiving system for use with pipeline equipment, which could be implemented as a part of the present invention, is shown in U.S. Pat. No. 5,651,638 entitled “METHOD AND APPARATUS FOR CONTROLLING THE POSITION AND OPERATION OF EQUIPMENT WITHIN A PIPELINE” and which issued Jul. 29, 1997 is incorporated herein by reference. 
   The buttons and switches on the remote control  122  can produce a digital code for each unique command and these digital codes can be transmitted to the receiver in the control box  76  where a decoder recognizes each code and a corresponding control signal is produced. A selected transceiver for use with the present invention is a digital spread spectrum radio such as manufactured by FreeWave Technologies, Inc., having an address of 1880 S. Flatiron Court Sts., Boulder, Colo. 80301. This radio functions as a digital spread spectrum (DSS) modem. A still further transceiver which can be utilized with the present invention is a Model WIT 2400 Wireless Industrial Transceiver, manufactured by Cirronet, Inc., having an address of 5375 Oakbrook Parkway, Norcross, Ga. 30093. 
     FIG. 5  illustrates the operation of the line-up unit  20  as it is positioned within a group of pipe sections  210  and  212 . The purpose of the line-up clamp  20  is to provide an accurate alignment between the abutting ends of the pipe sections  210  and  212  so that an external weld can be made on the abutting ends of these pipe sections with the tiles  54  providing back-up to the welding. When the process of welding the end of the pipe section  210  at its left end is completed, as shown in the drawing, the pipe section  212  is not yet in the position shown in  FIG. 5 , but is staged a short distance away awaiting use. The unit  20  is commanded to move forward toward the open end, the right end as shown in  FIG. 5 , of the pipe section  210  by operation of the remote control  122 . This can be done by pressing the auto travel button  200  shown in  FIG. 4  or moving switch  204  to the forward position. As the unit  20  travels forward, the whisker rods  79  are deflected against the interior surface of the pipe section  210 . When the whisker rods  79  on the nose cone  56  pass through the right end opening of the pipe section  210 , the whisker rods  79  deflect to a vertical position thereby indicating through the switches  115   a  and  115   b  connected thereto that the nose cone  56  has exited the end of the pipe section  210 . This causes the automatic application of the brake  36  to stop the unit  20 . Note that pipe section  212  has not yet been placed in the position shown in FIG.  5 . The operator using the remote control  122  then moves the toggle switch  174  ( FIG. 4 ) to the up position to extend the aligner members  68   a  and  74   a  so that the radially extended members of the aligners extend outside of the periphery of the pipe section  210 . The operator then releases the brake  36  and moves the toggle switch  204  ( FIG. 4 ) to the reverse direction such that the unit  20  begins to travel in the reverse direction thereby entering back into pipe section  210 . This continues until the extended aligner members engage the end of the pipe section  210  thereby stopping the unit  20 . The operator then uses remote control  122  to engage the brake  36  by operating toggle switch  162 . The operator then activates the rear shoes  50  to engage the interior of the pipe section by moving the toggle switch  180  to the up position. The aligner members are then retracted by moving toggle switch  174  to the down position. 
   Pipe section  212  is then moved into the position shown in FIG.  5 . Next, the operator uses remote control  122  to engage the front shoes by operation of toggle switch  186 , which also causes the back-up tiles to be engaged to the junction between the pipe sections  210  and  212 . The line-up clamp  48  is thus positioned to enable an external weld to be made at the abutting ends of the pipe sections  210  and  212 . After the external welding operation is completed, the front and rear shoes are retracted together with the back-up tiles, the brake of the unit  20  is released, and the unit  20  is moved forward through pipe section  212  to repeat the process for the next pipe section to be welded to the pipeline. 
   The process of operating the line-up equipment as described is significantly faster than the previous process which requires threading a reach rod or cable through each pipe section before it can be welded in place. It also allows the operator to work from an enclosed work station which is protected from adverse weather. 
   Although one embodiment of the invention has been illustrated in the accompanying drawings and described in the foregoing Detailed Description, it must be understood that the invention is not limited to the embodiment disclosed but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention.