Tetherless internal line-up unit for pipeline welding

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.

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.

DETAILED DESCRIPTION

A tetherless line-up clamp unit20in accordance with the present invention is shown in FIG.1. The line-up unit20is powered by an engine22, which is preferably a diesel engine. The engine22includes a radiator24having a fan which produces an air flow in the direction of arrow26. The engine22powers a hydraulic pump (shown inFIG. 2) which is positioned within a housing28. A battery30provides electrical power for the line-up unit20as well as a source of starting energy for the engine22. Engine22includes an alternator for charging the battery30. The unit20has a frame that supports the various components of the unit20. Engine22is mounted to the frame of unit20.

The line-up unit20is provided with an extendable brake36which can engage the interior of a pipe to hold the unit20in a fixed location. The unit20further includes a set of drive wheels38which are operated by a hydraulic drive motor (shown in FIG.2), for moving the unit20within a section of pipe. The unit20is lifted and transported by means of a lifting hook40that is attached to the frame of the unit20. The unit20is supported within a pipe section by wheels42,44and46. Wheels42and46provide the primary support. A corresponding set of three wheels (not shown) are located on the far side of the unit20illustrated in FIG.1.

The line-up unit20includes a line-up clamp48that includes rear shoes50and front shoes52. The clamp48further includes extendable back-up tiles54which 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 clamp48includes a first hydraulic actuator for positioning the rear shoes50(extended or retracted) and a second hydraulic actuator for simultaneously positioning (extended or retracted) the front shoes52and tiles54. These two actuators are located within the clamp48.

The line-up unit20is further provided with a nose cone56which is a part of the frame. The nose cone56comprises a plurality of tubular members which extend forward of the line-up clamp48and meet at a common support junction58.

An electric actuator64is mounted on the interior of the nose cone56and includes a movable rod66that is connected to an aligner68, which includes an L-shaped member68aand parallel rods68band68cwhich are pivotally connected to the member68aat one end and to a fixed frame member at the opposite end. The member68amoves along an arc as limited by the rods68band68c. The rod66drives the aligner68to extend the member68aradially outward and to retract the member68ato an inward, storage position. The rods68band68cpivot about the fixed ends thereof. The movable member68aextends radially outward for engaging the end of a section of pipe when the unit20is moved back into a pipe section.

An electric actuator70includes a moveable rod72that is connected to an aligner74which likewise has an L-shaped member74aand parallel rods74band74cthat are pivotally connected at one end thereof to the member74aand to a fixed frame at the opposite ends. Aligner74operates in the same manner as the aligner68described 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 unit20. 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 aligners68and74can 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 unit20further includes a control box76which is connected via a multi-line cable78to control solenoid valves in the unit20and through other cables to the aligner actuators64and70. The control box76is a transceiver, that is, it includes a transmitter and a receiver.

A pair of “whisker” rods79are connected to respective switches mounted to the nose cone56for indicating when the nose cone56has extended through the open end of a pipe section. The rods79swing downward when the nose cone56exits from a pipe section.

Referring toFIG. 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 engine22of the unit20is connected to drive a hydraulic pump80which is mounted within the housing28. The pump80drives hydraulic fluid through lines82to a manifold84. A set of solenoid valves86,88,90,92and94are mounted on the manifold84. Cable78is provided with five sets of electrical lines that are connected respectively to the solenoid valves86,88,90,92and94. The cable78is routed through the line-up clamp48.

The solenoid valve86is connected to hydraulic lines98which are connected to the hydraulic actuator for the front shoes52and back-up tiles54. The solenoid valve88is connected through hydraulic lines100to the hydraulic actuator for operating the rear shoes50. The solenoid valve90is connected through hydraulic lines102to a hydraulic cylinder104which functions to extend and retract the drive wheels38. Solenoid valve92is connected through hydraulic lines106to a hydraulic cylinder108that operates the brake36of the line-up unit20. Solenoid valve94is connected through hydraulic lines110to a hydraulic drive motor112that powers the drive wheels38of the line-up unit20.

The actuators64and70together with a third drive assembly71are connected through respective electric cables to the control box76.

The control box76, which is connected to the cable78, is mounted on the nose cone56to permit an operator to manually control the line-up unit20when the operator is in close proximity to the line-up unit20. The control box76includes a radio transceiver that has an antenna120. A remote control122includes a transceiver with an antenna124and this unit permits an operator to move and control the line-up unit20from a remote location by transmitting commands from the remote control122to the control box76by radio signals. The control box76is described in further detail in FIG.3and the remote control122is described in further detail in FIG.4. The remote control122and control box76utilize transceivers (transmitters and receivers) so that commands can be sent from the remote control122to the control box76for operating the various components of the unit20. 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 box76and is then transmitted back to the remote control122for 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 unit20, but provides substantial safety because the operator knows when a commanded action has been completed.

The control box76is coupled by a cable77to the engine22for starting and stopping the engine22.

The transceivers in the control box76and the remote control122can communicate directly with each other or optionally can be configured to communicate through a transponder126. The control box76will be located within a section of pipe and it may be necessary for the remote control unit122to be positioned at some point away from the pipe, such as due to adverse terrain or weather conditions. The transponder126can 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 box76and the remote control122. The transponder126can be located in any position where it can communicate with both the control box76and the remote control122. The reliability and consistency of communication between the remote control122and control box76can be improved by use of the transponder126.

In order to indicate to an operator using the remote control unit122when a commanded operation has actually been completed, the unit20is 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 cylinder108has associated with it proximity switches117aand117b. Proximity switch117ais activated when the brake36is in the retracted position and switch117bis activated when the brake36is in the extended position. Switches117aand117bare connected to the control box76. The hydraulic cylinder104functions to extend and retract the drive wheels38. A proximity switch119aindicates when the drive wheels are in the retracted position and a proximity switch119bis activated when the drive wheels are in the extended position. These switches are electrically connected to the control box76.

Proximity switches121aand121bare used to indicate respectively when the rear shoes50are in the retracted and extended positions. Proximity switches123aand123bindicate respectively when the front shoes52and the back-up tiles54are in the retracted and extended positions.

The whisker rods79are connected to or mounted near respective proximity switches115aand115bwhich are activated when the rods are essentially in the vertical position.

The actuator64, which operates an aligner assembly, works in conjunction with proximity switches125aand125bto indicate respectively when the aligner is retracted and extended. Actuator70works in conjunction with proximity switches127aand127bto indicate when the corresponding aligner is in the retracted and extended positions.

The third actuator71and aligner have corresponding proximity switches129aand129bto 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 box76is shown in FIG.3. The control box76is activated by a power switch130. The brake36of the line-up unit20is operated by a toggle switch132. When the brake switch is in the “OFF” position, the line-up unit20can be moved through the pipe, but when the brake switch is in the “ON” position, the line-up unit20is held in a fixed position by the brake. Toggle switch134has a neutral center position, but when pressed toward the left (the forward position), moves the line-up unit20forward in the pipe, toward the opening, and when pressed to the reverse position, causes the line-up unit20to move backward through the pipe. The diesel engine22is activated by pressing a start button136and deactivated by pressing a stop button138.

The drive wheels38are moved outward to engage the interior of the pipe surface when button140is pressed and are moved away from the pipe interior surface to a retracted, non-engaged position when button142is pressed. The aligner members68aand74a, and a corresponding third member, are extended radially outward when switch144is set to the “UP” position and these members are retracted when the toggle switch144is set to the “DOWN” position The rear shoes50are engaged to the interior of the pipe when a switch146is set to the “UP” position and are moved out of engagement with the interior surface of the pipe when the switch146is set to the “DOWN” position. The front shoes52are engaged with the interior of the pipe when a switch148is set to the “UP” position and are moved away from, that is retracted, when the switch148is set to the “DOWN” position.

The electrical system voltage for the line-up unit20is measured by a voltmeter150.

The remote control122is further described in reference to FIG.4. When the remote control122is in use, it provides substantially the same operational capabilities that are provided by the control box76. The remote control122includes a set of indicator lights (a visual display) for showing the actual position of moveable components of the unit20. The diesel engine22is started by depressing a “START” button158and is stopped by pressing a “STOP” button160. The brake36is operated by a command produced by a toggle switch162. When the toggle switch162is set to the “OUT” position, a command is sent from the remote control122to the control box76which 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 light64is turned on. When the switch162is set to the “IN” position, a command is transmitted to retract the brake and if this is done, a light166is activated to indicate that the brakes have been retracted. The lights164and166are activated respectively in response to the proximity switches117band117awhich respond to the position of the brake36.

The drive wheels38are engaged to the interior surface of the pipe when a toggle switch168is positioned to the “OUT” position and at the same time a light170is activated by switch119bto indicate that the drive wheels are engaged. When the switch168is moved to the “IN” position, the drive wheels38are retracted and this condition is indicated by a light172which responds to switch119a.

The aligner members68aand74a(seeFIG. 1) are driven to the extended position when the toggle switch174is set to the “UP” position and a light176is turned on by switches125b,127band129b. When the toggle switch174is set to the “DOWN” position, the aligners are retracted and a light178is turned on by switches125a,127aand129a.

The rear shoes50are driven into engagement with the interior of the pipe section when a toggle switch180is placed in the “UP” position. When this occurs, a light182is activated by switch121b. When switch180is set to the “DOWN” position, the rear shoes are retracted and a light184is turned on by switch121a. The front shoes52and back-up tiles54are engaged with the interior of the pipe section when a switch186is moved to the “UP” position and this results in the operation of the light188by switch123b. When switch186is set to the “DOWN” position, the front shoes and backup tiles are retracted and a light190is turned on by switch123a.

The line-up unit20is commanded to automatically travel and detect the end of the pipe by pressing a button200. This automatic travel state is indicated to be in operation when a light202is activated. The toggle switch204is used to manually position the line-up unit20within pipe. When the switch204is moved to the forward (FWD) position, the line-up unit20moves forward in the pipe, which is toward the next pipe section to be welded to the pipeline. When the toggle switch204is moved to the reverse (REV) position, the line-up unit20moves in the direction of arrow26away 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 control122can produce a digital code for each unique command and these digital codes can be transmitted to the receiver in the control box76where 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. 5illustrates the operation of the line-up unit20as it is positioned within a group of pipe sections210and212. The purpose of the line-up clamp20is to provide an accurate alignment between the abutting ends of the pipe sections210and212so that an external weld can be made on the abutting ends of these pipe sections with the tiles54providing back-up to the welding. When the process of welding the end of the pipe section210at its left end is completed, as shown in the drawing, the pipe section212is not yet in the position shown inFIG. 5, but is staged a short distance away awaiting use. The unit20is commanded to move forward toward the open end, the right end as shown inFIG. 5, of the pipe section210by operation of the remote control122. This can be done by pressing the auto travel button200shown inFIG. 4or moving switch204to the forward position. As the unit20travels forward, the whisker rods79are deflected against the interior surface of the pipe section210. When the whisker rods79on the nose cone56pass through the right end opening of the pipe section210, the whisker rods79deflect to a vertical position thereby indicating through the switches115aand115bconnected thereto that the nose cone56has exited the end of the pipe section210. This causes the automatic application of the brake36to stop the unit20. Note that pipe section212has not yet been placed in the position shown in FIG.5. The operator using the remote control122then moves the toggle switch174(FIG. 4) to the up position to extend the aligner members68aand74aso that the radially extended members of the aligners extend outside of the periphery of the pipe section210. The operator then releases the brake36and moves the toggle switch204(FIG. 4) to the reverse direction such that the unit20begins to travel in the reverse direction thereby entering back into pipe section210. This continues until the extended aligner members engage the end of the pipe section210thereby stopping the unit20. The operator then uses remote control122to engage the brake36by operating toggle switch162. The operator then activates the rear shoes50to engage the interior of the pipe section by moving the toggle switch180to the up position. The aligner members are then retracted by moving toggle switch174to the down position.

Pipe section212is then moved into the position shown in FIG.5. Next, the operator uses remote control122to engage the front shoes by operation of toggle switch186, which also causes the back-up tiles to be engaged to the junction between the pipe sections210and212. The line-up clamp48is thus positioned to enable an external weld to be made at the abutting ends of the pipe sections210and212. After the external welding operation is completed, the front and rear shoes are retracted together with the back-up tiles, the brake of the unit20is released, and the unit20is moved forward through pipe section212to 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.