The present invention relates to a wire saw with a sawing wire magazine.

The wire saw of the present invention is particularly developed to cut subsea structures below the level of a seabed. Subsea structures include conductors and platform legs and cutting is typically done down to 1000ft (300m).

It is a purpose to provide a saw with a small footprint on the seabed to reduce the required amount of dredging. Dredging the seabed is time consuming and cost intensive. Furthermore, it is a purpose of the invention to provide a wire saw that may be operated without diver intervention. Avoiding diver intervention dramatically improves HSE. Furthermore, it is a purpose of the present invention to provide a wire saw where the wire loop length not completely dictate the outer dimensions of the saw.

Typical wire saws for subsea use include a wire loop running in a plane between pulleys running on a frame. The plane of the entire wire loop is the same as the plane of the sawing or cutting plane and the frame has an area that is at least twice as big as the plane of the object to be cut. The size of the frame must also be sufficient to provide a tensioned wire length with adequate amount of abrasive material / cutting synthetic diamonds to perform the cut. The result is a saw with a rather large footprint when used on a seabed.

The wire saw design may have fixed outer dimensions allowing the saw to be installed in a cabinet without requiring impractically large outer dimensions. A cabinet may provide better operational conditions for parts of the wire saw as internal components may be less exposed to debris and mud from the seabed and the cutting process.

Accordingly, the present invention relates to a wire saw with a cutting portion with a U-shaped cutting area and cutting area sides. An endless sawing wire loop runs between a plurality of wire pulleys including at least two along each side of the U- shaped cutting area displaceable pulleys, at least one displaceable wire tensioning pulley and at least one wire plane changing pulley. The endless wire loop defines a first cutting area plane P1 in the U-shaped cutting area and at least one further wire loop plane dissimilar from the first cutting area plane. The at least one wire plane changing pulley guides the sawing wire between the first cutting area plane and the at least one further wire loop plane P2. At least one of said plurality of wire pulleys is a wire driving pulley in driving relationship with at least one wire drive motor. At least one cutting area pulley actuator is provided to run or linearly shift the cutting area pulleys along each side of the workpiece cutting area. The at least one displaceable wire tensioning pulley is displaceable by at least one tensioning actuator within the at least one further wire loop plane P2 to maintain a tensioned sawing wire.

The at least one cutting area pulley at each side of the workpiece cutting area may include an axis of rotation substantially perpendicular to, or with a small angle off perpendicular to the cutting area cutting plane P1 .

The wire saw may further include a sawing wire magazine frame and the at least one displaceable wire tensioning pulley may be supported by said at least one tensioning actuator displaceable tensioning frame and in the at least one further wire loop plane.

The plurality of wire pulleys may further include at least one wire loop accommodation pulley located in the at least one further wire loop plane.

The at least one wire loop accommodation pulley may be supported in the sawing wire magazine frame.

Two wire loop accommodation pulleys and two wire driving pulleys may be in driving relationship with two wire drive motors supported in the sawing wire magazine frame. Three displaceable wire-tensioning pulleys may be supported in the displaceable tensioning frame. The sawing wire magazine frame may be perpendicular to the cutting portion, and the first cutting area plane in the U-shaped cutting area may be perpendicular to the at least one further wire loop plane.

A magazine frame cabinet may enclose the sawing wire magazine frame.

The cutting area pulleys will normally be inclined in relation to the first cutting area plane P1 to rotate to sawing wire around its longitudinal axis.

A length of the workpiece cutting area lc may be greater than half a total length of the wire saw It in a plane P1 of the cutting area and in a direction perpendicular to a cutting portion of the cutting wire whereby the wire saw retains a small and fixed footprint during operation.

The outer dimensions of the wire saw may remain constant throughout a cutting operation.

The at least one displaceable wire tensioning pulley may be displaceable in a direction Dt parallel to a plane P3 parallel to a direction of travel Dr of the two displaceable pulleys and perpendicular to the cutting area plane P1 .

Fig. 1 is a perspective view of a wire saw of the invention ;

Fig. 2 corresponds to fig. 1 , but shows a sawing portion of a sawing wire in a final completely extended position after a cut through a workpiece is completed;

Fig. 3 is a perspective view from the rear of the wire saw of figs. 1 and 2;

Fig. 4 shows the embodiment of the figs. 1 -4 from above;

Fig. 5 is a view perpendicular to the view on fig. 4;

Fig. 6 is a schematic representation of a basic configuration of a wire saw;

Fig. 7 is a schematic representation of the configuration the wire saw as shown in fig. 1 ; and

Fig. 8 is a partly cut through side elevation of the embodiment of the invention shown in the fig. 1 to highlight the internal components. Fig. 1 is a perspective view of a wire saw of the invention with a sawing portion of a sawing wire 1 in an initial completely retracted position. This is the position of the sawing wire before the wire saw start cutting. The wire saw includes a sawing wire magazine with a magazine frame 2 defining a magazine frame plane perpendicular to or orthogonal with a fork shaped runner frame 4 defining a sawing plane. A tensioning frame 3 is movable inside the magazine frame 2 along a plane parallel to or coinciding with the magazine frame plane. The tensioning frame is shown in a lower position. The tensioning frame 3 moves in the magazine frame plane and in a direction parallel to a plane parallel to runners for two cutting gap saw wire pulleys and perpendicular to the sawing plane. Two wire drive motors 6 with drive pulleys 12 are fixed to an upper part of the magazine frame 2 along with two magazine frame pulleys 10. Three tensioning frame pulleys 1 1 are fixed to the tensioning frame 3. The tensioning frame and the magazine frame pulleys 10, 1 1 and the drive pulleys 12 rotate in a plane parallel to or coinciding with the magazine frame plane. The tensioning frame and magazine frame pulleys 10, 1 1 and the drive pulleys 12 also serve as accommodation pulleys to accommodate a wire of sufficient length. The number of pulleys may be increased or decreased depending on the required length of the sawing wire, constraints relating to outer dimensions of the saw and concerns relating to the force imposed on the structure. The sawing wire 1 extends between the tensioning frame and magazine frame pulleys 10, 1 1 and the drive pulleys 12 in a zigzag pattern. The two cutting gap saw wire pulleys are in a retracted position in the fork shaped runner frame 4 and are not visible. A workpiece 19 is located between runners of the fork shaped runner frame 4.

Fig. 2 corresponds to fig. 1 , but fig. 2 shows the sawing portion of the sawing wire 1 in a final completely extended position after a cut through the workpiece is completed. Workpiece clamps 5 are in a forward position for holding the wire saw to a workpiece (as shown in figs. 1 and 3). The cutting gap pulleys 8 are movable along the sawing plane and are shown in an extended position along the fork shaped runner frame 4. Cutting gap pulley linear actuators 9 with runner tracks move each cutting gap pulley 8 individually along the fork runner frame 4. Fig. 2 shows the tensioning frame 3 with the tensioning frame pulleys 1 1 in an upper position in the magazine frame 2 with the magazine frame pulleys 10. The wire drive motors 6 supports the drive pulleys 12.

Fig. 3 shows the wire saw of figs. 1 and 2 in a perspective view from the rear. The sawing wire 1 and the tensioning frame 3 are in the same position as in fig. 2. A tensioning frame actuator 7 drives the tensioning frame up or down inside the magazine frame 2. One corner pulley 1 3 in each corner between the magazine frame 2 and the fork runner frame 4 allows the sawing wire 1 to move in a sawing plane that is perpendicular to or close to perpendicular to the sawing wire magazine plane. Tracks in the magazine frame 2 and runners on the tensioning frame 3 enables the tensioning frame 3 to shift between the upper and lower position in the magazine frame upon actuation by the actuator 7.

Fig. 4 shows the embodiment of the figs. 1 -4 from above. The sawing wire and the workpiece clamp 5 are in the same forward position as on fig. 2 and 3. The sawing portion of the sawing wire 1 and the cutting gap pulleys 8 are in a forward position along the cutting gap pulley linear actuators 9. The workpiece clamp 5 include two pivoted clamp arms 14 pivoted in clamp arm pivot joints 16 and actuated by two clamp arm actuators 15. The clamp arms 14 press a workpiece contact pad 17 and workpiece alignment elements 18 toward the tubular workpiece (not shown). The work piece alignment elements 18 also serves to fix one end of each clamp arm actuator 15. The cutting area linear actuators 9 include runner tracks. Fig. 4 also shows that the length of the workpiece cutting area lc is greater than half the total length of the wire saw It. The magazine thickness tm is also less than the length of the workpiece cutting area lc. The width of the cutting area wc, approximately equals the length of the cutting area lc. The workpiece cutting area lc x wc can span over more than half the total footprint area.

Fig. 5 shows the embodiment of the figs. 1 -4 from the front in a view perpendicular to the view on fig. 4. The cutting gap pulleys 8 and the corner pulleys 13 are aligned with each other to ensure that the cutting wire enters the cutting gap pulleys at the right angle. The cutting gap pulleys 8 rotate in a plane that is slightly inclined in relation to the sawing plane to rotate the sawing wire 1 along its longitudinal axis during operation. The tensioning frame is close to its uppermost position.

Fig. 6 is a schematic representation of a basic configuration of a wire saw with a sawing wire 1 in an endless wire loop running in a first cutting area plane P1 in a U-shaped cutting area and at least one further wire loop plane P2 dissimilar from the first cutting area plane. Two wire plane-changing pulleys 13 guide the wire between the two cutting area planes P1 , P2. Two along the sides of the U-shaped cutting area displaceable pulleys 8 are displaceable in the direction of the two horizontal arrows in the first cutting area plane P1 . The displaceable wire tensioning pulley 1 1 is displaceable by at least one tensioning actuator in the direction of the substantially vertical arrow within the at least one further wire loop plane to maintain tension in the wire. Fig 6 furthermore shows how the tensioning pulley 1 1 moves in a direction Dt parallel to a plane P3. The plane P3 is parallel to the direction of travel Dr of the two displaceable pulleys 8 and perpendicular to the cutting area plane P1 .

Fig. 7 is a schematic representation of a configuration of a wire saw that similarly with the solution shown on fig. 6 includes an endless wire loop running in a first cutting area plane P1 in a U-shaped cutting area and at least one further wire loop plane P2 dissimilar from the first cutting area plane. Two wire loop accommodation pulleys 10 (same as the tensioning frame pulleys) and two wire driving pulleys 12 in driving relationship with two wire drive motors are fixed. The two wire driving pulleys 12 also serves as accommodation pulleys to enable a sufficiently long wire. Three displaceable wire tensioning pulleys 1 1 are movable in a direction of the arrow to the left of the figure to maintain the wire in tension when the displaceable pulleys 8 are displaced in the direction of the two horizontal arrows in the first cutting area plane P1 . Two wire plane changing pulleys 13 or corner pulleys enables the wire loop to run between the two planes P1 , P2. Alternatively could the position of the accommodation pulleys 10 be movable and the position of the wire tensioning pulleys 1 1 be fixed. Fig. 8 is a partly cut through side elevation of the embodiment of the invention shown in the figures 1 -5. The wire drive motors 6 supporting the wire drive pulleys 12 are located in in the upper part of the magazine frame. The corner pulleys 13 guides the cutting wire 1 between the cutting area plane and the magazine or accommodation plane. These two planes are perpendicular to each other. The workpiece clamp 5 is provided above the cutting area plane and the cutting area pulleys 8. An actuator motor 7 drives the tensioning frame up and down to ensure that the sawing wire has the required tension.

The sawing wire tension is monitored and the cutting gap pulley linear actuators, the wire drive motors, the tensioning frame actuator are individually controllable and controlled to ensure correct sawing wire tension in all parts of the sawing wire and to prevent skidding of the wire on the drive pulleys and overloading the wire. The individual control of the sawing parameters is also useful in the event of wire jamming, and the twin wire drive motor set up also enables the sawing wire to be run in both directions without changing the overall load pattern and without overloading the tensioning pulleys. The control system of the wire saw typically monitors and controls sawing parameters such as sawing wire tension in several location, motor speed, motor torque, position of actuators, speed of pulleys, force on pulleys, force on actuators, motor temperature etc. The sawing could be controlled in real-time to prevent wire breakage in the event of wire jamming, prevent slippage on pulleys to prevent premature wear of pulleys, to alter sawing parameters to control sawing wire load etc. A topside operator typically controls the saw through an umbilical. The motors and actuators will normally be electric, but hydraulic actuators and /or motors can also be used.

The term "frame" is intended to cover structures able to form platforms for the various components and to maintain the required positions of the pulleys and other components.

The workpiece is typically a 70" (1778mm) pipe, and the wire length is typically 19m to provide a sufficient amount of abrasive / cutting material on the sawing wire. Sawing wires with abrasive or cutting material such as embedded synthetic diamonds are well known within the art.

1 Sawing wire

2 Sawing wire magazine frame

3 Tensioning frame

4 Cutting portion

5 Workpiece clamp

6 Wire drive motors

7 Tensioning frame actuator

8 cutting area pulleys

9 cutting area linear actuators

10 accommodation / magazine frame pulleys

1 1 Tensioning frame tensioning pulleys

12 Drive pulleys

13 Corner pulleys

14 Clamp arms

15 Clamp arm actuators

16 Clamp arm pivot joint

17 Workpiece contact pad

18 Workpiece alignment element

19 Work piece