Metal fusion bonding – Including means to force or clamp work portions together... – Comprising tube aligning means
Reexamination Certificate
2001-06-06
2002-05-14
Dunn, Tom (Department: 1725)
Metal fusion bonding
Including means to force or clamp work portions together...
Comprising tube aligning means
C228S049300
Reexamination Certificate
active
06386421
ABSTRACT:
FIELD OF INVENTION
The present invention relates to an actuation system for a clamping assembly for use in a pipe clamping apparatus. Further, the present invention relates to an internal clamping assembly for a pipe, preferably a backup ring assembly, and to a pipe clamping apparatus comprised of the clamping assembly.
BACKGROUND OF INVENTION
Typically, a pipeline is constructed of a number of pipe lengths or sections which are placed end to end and welded together at the respective adjacent ends as the construction of the pipeline proceeds. In order to achieve a desirable weld between the adjacent ends, the ends of the pipe sections must be clamped or held in close proximity. For this purpose, various pipe clamping apparatuses have been developed for clamping the pipe sections for welding.
Once the clamping apparatus is in place, the welding is typically performed by a welding device outside of or exterior to the pipe sections. During the welding operation, a weld backup ring is preferably provided on the inside or interior surfaces of the pipe sections at the location of the abutment of the adjacent ends of the pipe sections. The backup ring is desirable for supporting the weld pool which would otherwise fall into the pipe sections during the welding operation. Also, the backup ring facilitates the formation of a relatively smooth circumferential weld internally of the pipeline.
Several conventional clamping apparatuses and associated backup rings are described in United Kingdom Patent Application 2,067,945 published Aug. 5, 1981 by Rinaldi, Canadian Patent Application 2,183,156 published Aug. 17, 1995 by Brookhouse, U.S. Pat. No. 5,535,938 issued Jul. 16, 1996 to Leduc, U.S. Pat. No. 3,979,041 issued Sep. 7, 1976 to Kaneyama, U.S. Pat. No. 4,177,914 issued Dec. 11, 1979 to Clavin, U.S. Pat. No. 4,201,326 issued May 6, 1980 to Connell, U.S. Pat. No. 4,285,458 issued Aug. 25, 1981 to Slavens, U.S. Pat. No. 3,741,451 issued Jun. 26, 1973 to Gwin, U.S. Pat. No. 3,937,382 issued Feb. 10, 1976 to Cunningham and U.S. Pat. No. 5,110,031 issued May 5, 1992 to Rinaldi.
Such conventional clamping apparatuses are typically capable of self-propulsion through the pipeline and include independently operable front and rear clamping mechanisms for clamping the adjacent pipe sections for welding and a backup ring for providing backup support at the weld. More particularly, the front pipe clamping mechanism comprises a plurality of clamping shoes radially movable between a retracted position and an extended position for engaging the interior surface of the front pipe section. The rear pipe clamping mechanism is also comprised of a plurality of clamping shoes radially movable between a retracted position and an extended position for engaging the interior surface of the rear pipe section.
The backup ring is similarly comprised of a plurality of segments movable between a retracted position and an extended position for engaging the interior surface of the front and rear pipes at their adjacent ends. Typically, the backup ring, is mounted with the front and rear pipe clamping mechanisms. For instance, the backup ring may either form part of, or be extendible and retractable simultaneously with, one or both of the front and rear clamping mechanisms of the associated pipe clamping apparatus. However, the backup ring may be also be retractable and extendible independently of the clamping mechanisms.
Each of the above apparatuses tends to have a relatively complicated or complex structure and tends to be relatively large-scaled. As a result, each apparatus tends to be primarily useful in larger diameter pipes. In other words, the structure and size of each of these apparatuses may result in difficulties when attempting to reduce the size of the apparatus for smaller diameter pipes. Accordingly, various attempts have been made to provide a pipe clamping apparatus which may be reduced in size to be particularly useful for medium to smaller diameter pipes, such as those having a diameter of between about 16 inches (40.64 cm) and 32 inches (81.28 cm). However, none of these attempts have been fully satisfactory.
Canadian Patent No. 1,060,488 issued Aug. 14, 1979 to Lajoie et. al. is directed at a pipe clamping apparatus comprised of a longitudinally disposed piston rod having a pneumatic piston fixed at one end thereof which is movable within a stationary cylinder. A plurality of radial elements for engaging the interior surface of the pipe are coupled with the other end of the longitudinal piston rod by a plurality of links or toggles. Specifically, the plurality of links or toggles attach or connect each of the radial elements to the longitudinal piston rod. When the piston is energized, the piston and the piston rod affixed thereto move as a unit longitudinally in a direction towards the links to apply a longitudinal force. The longitudinal force creates a compressive force in the links or toggles connected between the piston rod and the radial elements to move the radial elements radially outwards to engage the pipe surface. When the piston is no longer energized, the piston is biased by a compression spring to return to its initial position to move the radial elements radially inwards to disengage the pipe surface.
Canadian Patent No. 1,269,825 issued Jun. 5, 1990 to Okamoto describes a device for internally clamping pipes comprised of a longitudinally disposed guide bar and a pair of axially spaced apart pressure chambers or cylinders. A piston is fitted movably around the guide bar within each pressure chamber such that the piston is movable along the stationary guide bar within the chamber. A plurality of retractable clamps for engaging the inner surface of the pipe are connected with, and actuated by, each of the pistons by a plurality of actuating links. In other words, the plurality of actuating links attach or connect each of the clamps to one of the pistons. To actuate the device, pressurized fluid is supplied to each pressure chamber which acts upon each piston to move the piston longitudinally along the guide bar within the pressure chamber. Longitudinal movement of the piston along the guide bar causes the actuating links connected with each piston to move the clamps radially outwards for engagement with the pipe surface. Return springs are provided for acting upon each piston to return the piston to its initial position to retract the clamps upon release of the fluid pressure.
U.S. Pat. No. 3,937,382 issued Feb. 10, 1976 to Cunningham also describes a clamping apparatus which includes a first and a second set of clamping members and a weld backup mounted about a central shaft. The mechanism for actuation of the clamping members differs from the mechanism for actuation of the weld backup. Each set of clamp members is actuated by a longitudinally disposed piston rod slidably received upon the central shaft and rigidly coupled with a piston at one end thereof, which piston is movably received within a stationary cylinder. A hub is rigidly affixed to the piston rod. Further, the clamp members are coupled with the hub by a plurality of links or toggles. Specifically, the plurality of links or toggles attach or connect each of the clamp members to the hub which is rigidly affixed to the longitudinal piston rod. When the piston is energized in a first direction, the piston, the piston rod and the hub affixed thereto move as a unit longitudinally in a direction towards the links. Longitudinal movement of the hub along the central shaft causes the links connected between the hub and the clamping members to move the clamping members radially outwards for engagement with the pipe surface. Energization of the piston in an opposed direction moves the piston, the piston rod and the hub as a unit longitudinally in an opposite direction away from the links to move the clamping members radially inwards to disengage the pipe surface.
The weld backup is comprised of a central hub which is rigidly mounted about the central shaft and a ring housing which is rigidly mounted with the central hub. The ring ho
Anderson Clifford J.
Sawa Mark R.
Thicke Brian R.
Dunn Tom
Proline Pipe Equipment Inc.
Rodman & Rodman
Stoner Kiley
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