Patent Application
20130008881
The invention is generally related to the automatic pipe welding process and, more particularly, to the simultaneous and independent control of multi-carriage/multi-torch arrangements.
Pipeline welding has evolved over the years from manual welding to single head semi-automatic orbital welding, to multiple-head automatic welding. Each new method came with improvements in quality and productivity. However, the latest approach was not able to achieve its theoretical maximum potential because of its inability to control all parameters of each welding head independently, particularly velocity and acceleration. Also, these machines lack the ability to provide the clearances that nozzles and other large attachments require.
Automatic welding systems generally consist of one or more welding torches, a circular race concentric to the pipes to be joined, and a motorized carriage (normally referred to as a “bug”) that carries the weld heads and some ancillary equipment along a weld seam. The circular race has a clamshell design that is hinged at one end and installed manually over the tubes. This is the most common method for orbital welding of pipelines. Its drawbacks are long set-up times and single carriage operation.
Another approach is to use one or two continuous races supported on a stationary frame that has multiple welding heads mounted at fixed intervals. Here the carriage is a complete or partial ring where two or more welding heads are mounted. This approach allows for multi-torch simultaneous operation, but it does not allow for independent velocity/acceleration control of each weld head.
The present invention is drawn to an arrangement that allows for real-time independent control of all carriages, torches, and ancillary components by design. The invention uses a split-ring race that is mounted on a backing ring of similar design. Numerous welding heads are mounted on carriages that are distributed at set intervals along the circumference of the race. The left and right side race and backing ring assemblies are split at the twelve o'clock and six o'clock positions. They can be decoupled and spread apart horizontally to facilitate installation and for clearing obstacles. Alignment tools (tapered pins) facilitate assembly. Locking devices located near each split interface, coupled with the alignment pins, assure that the race acts as a continuous unit during the welding operation. Linear actuators mounted on the backing rings maintain concentricity between the race and the welded tube and act as a positive clamping system. They also maintain perpendicularity between the axis of the pipe and the plane of the split race.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. For a better understanding of the present invention, and the operating advantages attained by its use, reference is made to the accompanying drawings and descriptive matter, forming a part of this disclosure, in which a preferred embodiment of the invention is illustrated.
In the accompanying drawings, forming a part of this specification, and in which reference numerals shown in the drawings designate like or corresponding parts throughout the same:
As seen in
As seen in
Each half is provided with locking means 20 (attached to the backing rings 14) which is comprised of one portion with a prong 36 and a second portion with a receptacle 38 for receiving the prong 36. Prong 36 is received in receptacle 38 and rotated to lock the two halves of the welding apparatus 10 together.
Circular race 16 is provided with grooves 40, best seen in
Also attached to each welding carriage 44 are a welding torch holder 50, a welding torch 52, a vertical slide 54, a vertical slide drive motor 56, a horizontal/axial slide 58, and a horizontal/axial slide drive motor 60. The vertical and axial slides 54 and 58 each use a screw drive to move a plate on the screw in a manner that is generally known.
The axial slide 58 is attached to the movable plate 62 of the vertical slide 54 (best seen in
Means 22 for securing the welding apparatus 10 in position to and around a pipe 12 for welding operations is provided in the form of a plurality of linear actuators 66 and linear actuator feet 68 spaced around each backing ring 14.
In operation, each half of the welding apparatus 10 is preferably mounted on left and right side manipulators 70 of a lateral base slide 72. The manipulators 70 are mounted on the base slide 72 so as to allow selective motion of the manipulators 70 to move the welding apparatus 10 between open and closed positions. The manipulators 70 are positioned so as to have the welding apparatus 10 in the open position as seen in
A section of pipe, which may or may not have a coating 74 applied, is positioned so as to preferably be coaxial with the two halves of welding apparatus 10 and a section of pipe 12 to be added is also placed in position as seen in
Weld area scanning means 28 and vertical and axial slides 54, 58 are used in conjunction to scan the weld seam area and position and move the welding torches 24 vertically and axially to weld the two pipe sections together while they are rotated around the pipe by pinion gears 46 and drive motors 48.
The invention provides several advantages.
Set up times are reduced by having the welding apparatus split into two halves that are designed to be aligned and form a continuous circle when brought together.
The two halves of the apparatus allow it to be opened to facilitate installation of the pipe and for clearing obstacles on the pipe.
Multiple welding heads are provided for simultaneous operation.
The multiple welding heads are capable of independent control for velocity and acceleration.
While specific embodiments and/or details of the invention have been shown and described above to illustrate the application of the principles of the invention, it is understood that this invention may be embodied as more fully described in the claims, or as otherwise known by those skilled in the art (including any and all equivalents), without departing from such principles.
