A DEVICE FOR CUTTING LARGE-DIAMETER PIPES Technical field

The present invention concerns the technical field relative to the technologies for cutting pipelines.

In particular, the invention refers to an innovative machine capable of making a cool cut of a large diameter pipeline destined to the distribution network for the transport of gas, oil or hydrocarbons in general.

Background art

It is known that large diameter pipelines (diameters generally superior to the 40-50 centimetres) have long been used for the transport of gas (gas pipelines), hydrocarbons, oil or other forms of fluids, often for energetic use.

Such pipelines are generally laid underground and branch off for thousands of kilometres, connecting also different regions or countries. Through such pipelines, it is possible the transport of crude oil, gas or hydrocarbons in general, which re-furnish areas very distant from each other.

It is therefore clear that, in all the distribution network, interventions that imply the removal and substitution of some stretches are often necessary.

A first common case of intervention is due to ordinary maintenance, for example when certain stretches are not structurally idoneous anymore to perform their function due to wear. In other cases, it is instead necessary to remove the pipeline not so much because of a question of maintenance, but because of a need of substitution of the duct with pipelines of different diameters, for example to increase the capacity. In all the cases mentioned, in accordance with the background art, it is therefore necessary a first phase that foresees the excavation of a channel to bring to light the stretch of pipeline of interest on which the intervention is foreseen. Subsequently, it is necessary to widen and secure the excavated channel so that a team of specialized operators can enter inside the channel and operate the cut manually in safety conditions.

Before operating any cut intervention, it is necessary to foresee the interruption of the fluid flow that is transported by the pipeline and the check of the quantity of residue hydrocarbons present in the duct itself.

The cut is then executed manually through the use of an oxyacetylene torch commonly called "ossirotor".

This cut operation must however be preceded by a removal operation of the coating in polyethylene generally arranged all around the pipeline as anticorrosive protection. Such a type of protection is in fact in an inflammable material and is therefore clear that its removal is essential in terms of work safety, since the cut technique in fact foresees the use of a flame that could cause the beginning of a fire.

Subsequently, the operations of manual cut through the use of said torch and of removal of the cut stretch are realized.

Considering what has been said, numerous technical inconveniences relative to such a known technology are clear .

The first inconvenience is related to the need of excavating a channel of such a width as to allow work manoeuvres to the team of operators destined to operated directly within the channel. Moreover, it is necessary to foresee to secure the channel to avoid the collapse of the walls.

The whole therefore causes an inevitable increase of the working times and of the execution costs. In addition, the need of having operators placed inside the channel inevitably implies a high risk both in the cutting phase that subsequently in the lifting and removal phase of the cut pipe.

Moreover, due to the risk of explosions, it is necessary to foresee, before making any cut, said explosiveness test, which comprises the realization of a hole in the pipeline with a non-sparking drill in such a way so that a measuring device can be introduced to check the real quantity of hydrocarbons or stagnant explosive materials inside the pipeline. This operation also contributed significantly to increase the costs and the working times. Moreover, as a consequence of such explosion risks, it is always requested the permanent presence of anti-fire teams that accompany the operators during all the operative phases.

A further technical problem, which is added to the preceding ones, concerns the use of an oxyhydrogen torch for the cut of the pipe. This technique requires obligatorily, as already said, a manual removal of the coating tape, the whole with a further dilation of required working times. Moreover, the removal of such a coating implies a management problem of the separated waste that contributes to increase the costs.

In case the cut with oxyhydrogen torch technique is not applicable, for example because the explosiveness test has shown dangerous traces of waste inside the pipe, there is obligation of resorting to the current cool cut techniques .

These techniques are substantially based on two types of quite equivalent cut for the removal of material. In a first case a chain is used which is tightened around the pipe and made to rotate at a pre-determined speed. The fiction causes a progressive removal of the material until the cut is completed.

In a second case a circumferential milling cutter is used, which runs along the external circumference of the pipe, removing progressively material at each turn until the cut is completed.

In both cases, however, such an operation requires a very long time for the completing of the cut, of the order of about two hours.

E' dunque evidente come, anche in questo caso, i tempi operativi risultano troppo elevati.

In order to solve said technical problems, a solution has been proposed in publication US2010/0043609 that lends itself well to a check of cut also from remote, therefore securing the safety of the operators and without requiring the use of oxyhydrogen torch.

The device described in US2010/0043609 foresees two clamps hinged to the frame and semi-circular in shape, so that they · can grasp the pipe during the cut. The two clamps are activates in rotation one towards the other through an actuator. It is then foreseen a translatable blade, of the guillotine type, arranged in a seat in the frame in such a way that it can lower in the circular space delimited by the two clamps. To that aim, both the right clamp and the left clamp are shaped in such a way that, when reclosed one against the other, form a superior opening for the entry of the blade and an inferior opening for the exit of the end of the blade once the cut has been made .

This type of solution, however, has the technical inconvenience of substantially allowing the use of a single blade moved vertically, that is guillotine-like. This implies a less precise cut, therefore causing a high buckling in the back of the pipe. Moreover, this solution limits the width of the selected blade to the grasping diameter defined by the clamps when closed. The application of other blades in combination with those guillotine-like, for example two opposed rotatable blades, results hardly applicable in a solution as the one described, above all considering that all the blades have to act on the same cut plane.

A second solution has been proposed in

US2008/0155832, wherein a system with block clamps and a cutting system formed by two blades rotatable in a shearlike manner overlapped to the clamps are foreseen. The pipe, placed in vertical position, is grasped by the clamps on one side and cut by the shears in the superior part .

It is clear that this solution is absolutely inefficient in the case of cuts of large diameter pipelines. In fact, it is not versatile since the clamps and the shears are on two different planes and this renders the manoeuvrability difficult. Moreover, the cutting, taking place on a plane distanced from the grasping plane, causes such inflexions of the whole pipeline and bucklings as to render the remaining part unusable to make the connection to a new portion of pipe.

Disclosure of invention

It is therefore the aim of the present invention to provide a new type of equipment for operating the cool cut of large diameter pipelines (generally destined to the transport of hydrocarbons, gas or oil) , which solves at least in part said inconveniences.

In particular, it is the aim of the present invention to provide an ^' equipment that is capable of operating a cool cut in a very quick time, thus reducing to the minimum the working times, in spite of the large dimensions and the particular hardness of such pipelines.

It is also the aim of the present invention to provide a new equipment that allows the cut safeguarding the total safety of the operators.

In particular, it is the aim of the present invention to provide an innovative type of equipment that allows contextually the cut and, subsequently, the lifting of the pipeline from the channel, without the need of having operative staff placed inside the channel.

It is also the aim of the present invention to provide an innovative type of equipment that substitutes efficiently the traditional oxyhydrogen torch, thus eliminating totally the risks of fire or explosions, though allowing a quick cut.

It is therefore the aim of the present invention to provide an equipment that allows a quick and precise cool cut, minimizing the inflexions of the pipeline and the bucklings in the entry point of the blade, in such a way that it is not necessary anymore to have to move away of a big distance from the cut section to find the original circularity of the pipeline.

These and other aims are therefore obtained with the present equipment 1 for operating the cool cut of pipelines 100 as per claim 1.

In accordance with the invention, the equipment (1) foresees :

A support frame (2) comprising two plates (3', 3'') opposed and distanced in such a way as to leave a free space comprised between them;

- A block device (10, 15, 80) through which to grasp and block the pipe (100) to be cut;

- One or more mobile blades (70, 85);

- At least one actuator (60, 90) through which the activation of the blades (70, 85) takes place to make the cut of the blocked pipeline (100) .

In accordance with the invention, the block device comprises now two front clamps (10, 15) hinged to the plate (3' ) and two back clamps (10, 15) hinged to the plate (3'') and an actuator (50) arranged in such a way as to cause an opening/closing motion of the clamps to realize the grasping of the pipe (100). The front clamps and the back clamps are distanced between them. This reciprocal distance between the two pairs of clamps therefore allows the application of the cut blades in such a way that these, when activated, pass through the space comprised between the two pairs. In fact, in accordance with the invention, the one or more mobile blades (70, 85) are arranged in such a way as to pass inside the free space in the space comprised between said two pairs of clamps (10, 15) at least during the cutting phase.

This solution with two pairs of clamps that face one the other and distanced, therefore allows a strong grasp, since the grasp takes place upstream and downstream of the blades that make the cut. Contextually, in accordance with said solution, it is now possible the easy application not only of a guillotine-like blade, but also of more blades (for example, a translating one and two shear-like rotatable ones) that act on the same plane. The space between the two pairs of clamps in fact allows an easy application of the cut devices necessary precisely in the free space of the two plates and therefore straddle the clamps. A quick cut is therefore obtained, because it is eventually operable with many lames at the same time, the wear of the blades is reduced because each blade is now less loaded and it can now be freely selected any area of blade without being bound anymore to the internal diameter of the clamps or foresee complex cutting elaborations of them (cutting 133 as in US2010/0043609) .

Further advantages can be deduced from the dependent claims.

Brief description of drawings

Further features and advantages of the present equipment for operating the cutting of pipelines, according to the invention, will result clearer with the description of one of its embodiments that follows, made to illustrate but not to limit, with reference to the annexed drawings, wherein:

- Figure 1 show a front view of the present equipment 1 in accordance with the invention;

- Figure 2 shows an axonometric view of the present equipment 1 in accordance with the invention;

- Figure 3 shows a lateral view;

- Figure 4 shows the blades extended inside the circular area defined by the clamps and by the stopping surface 80;

- Figure 5 shows a front view a cross-section that highlights the vertical blade 85;

- Figure 6 shows an axonometric view a lifting phase of the pipe cut with the clamps closed to maintain the grasp of the pipe.

Description of some preferred embodiments

Figure 1 shows an equipment 1 for the cool cut of pipelines 100 which are destined to the energetic transport of gas or hydrocarbons in general.

Such pipelines, as it is well known, have diameters above the 40 cm or 50 cm and can be realized in metal, or cement or reinforced concrete. Due to their large dimensions, weights and thickness, it is necessary to have a particularly strong machine of high performance to make such a cool cut in a clear and quick manner, limiting to the maximum the deformation of the cut edges. To that aim, the equipment 1 comprises a frame 2 that serves as support for the structural elements described below.

Such a frame 2, for example generally quadrangular- shaped or of any other shape, is formed by two plates 3' and 3'' joint between them in an opposed manner in such a way as to leave a free space comprised between them (see for example figure 2) . Such a space is used for the positioning and sliding of the blades destined to operate the cut of the pipe as well as for the placement of movement organs, as better described in detail below.

The frame 2 serves, as already said, as support for the following components here described from the structural point of view.

In particular, two mobile front clamps 10 and 15 and two mobile clamps identical to the preceding ones but back ones are foreseen, that is the first pair connected to the plate 3' and the second pair connected to the opposed plate 3' ' (see also figure 3) .

More in particular, a first pair 10 and 15 is hinged, through rotation pivots 25, in a pre^chosen point of the plate 3' , preferably each one in proximity of the inferior edge of the plate itself.

The two clamps are therefore arranged in such a way as to result symmetrical (as also the whole equipment 1) with respect to a transversal plane 66 (orthogonal plate contextually to the ground and to a plane 65 of containment of the equipment).

The clamps 10 and 15 are configured in such a way as to have a circular shape along their grasp surface 18 so that they can follow well the circular profile of the pipe 100 when it is going to be grasped. The superior end of the clamps is instead connected to an actuator 50 formed by a simple jack 50 of the pneumatic, hydraulic or oleo- pneumatic type. The jack is hinged by its two ends 51 and 52 to the ends of the clamps in such a way that, according to its extended or retracted position, controls an opening and closing rotation of the clamps around their hinge point 25.

Figure 2, for example, shows a retracted position of the jack 50 such as to release the cut pipe 100. Figure 6 instead shows an extended position of the jack 50 such that the clamps have rotated clockwise to reclose themselves closet o the pipeline 100 so as to grasp it, for example before operating the cut, or after the cut, to remove the pipeline from the channel where it results arranged.

As can be seen from the figures attached, and in particular from figure 3, the present equipment 1 presents a second symmetry, and in particular a symmetry with respect to the plane 65, defined plane of containment of the equipment here. In such a sense, with respect to said plane 65, in an absolutely mirror-like manner, two clamps (10, 15) are present and a jack 50 identical to the ones already described.

Going on with the structural description of the invention, the free space comprised between the two plates (3', 3'') serves for holding the cut organs of the pipeline and of their actuating devices.

In particular, as shown in figure 1, these foresee two blades 70, each one fixed to a blade-holder 71. The blade-holder 71 has also a semi-circular profile along its perimeter on which the blade 70 is fixed in such a way that the blade can penetrate completely during the cut until the blade-holder reaches the profile of the pipe 100 to be cut.

The blade is substantially fixed to the blade-holder 71 through ordinary bolts in such a way as to result exchangeable when worn.

An end 71' of the blade-holder (see figure 2) is hinged in a rotatable manner to the frame 2 in such a way that the blade-holder results comprised in the space formed between the front plate 3' and the back plate 3' ' .

Such an end 71' is preferably in axis with the hinge 25 (see figure 3) in such a way that a single pivot serves as pivot for both the clamp (10, 15) and the blade-holder 71. A second end 71' ' is instead hinged to a jack 60, preferably of the hydraulic type, or of the pneumatic or oleo-dynamic type. Obviously, the jack 60 results comprised as well between the two plates 3' and 3'' and is hinged to the opposite end to the plates with a hinge 19. Such a type of connection therefore renders the blade- holder 71 rotatable with respect to the frame to which it is assembled.

The two blades (and therefore the blade-holder) are perfectly symmetrical with respect to said axis 66 so that it can cut the pipe 100 in an efficient manner through its diameter on two opposite sides.

In particular, the extraction and retraction motion of the two jacks 60 causes the respective clockwise/anticlockwise rotation of the blade-holder 71 for the cut. More in detail, the extraction of the jack 60 causes a rotation of the blade-holder 71 in clockwise sense to cut the pipe (see figure 4), while a retraction of the jack cause san anti-clockwise rotation that makes the blade exit from the diameter of the cut pipe (see figure 5) .

Figure 6 highlights clearly how the frame 2 is configured in such a way as to form a stopping surface 80, or superior stop 80. The stop 80 is also semicircular-shaped in the part destined to the contact with the profile of the pipeline 100 in such a way that the equipment can lean well on the back of the pipeline 100 to be cut, as better described in detail in the part of description that follows.

In particular, the stopping surface 80 can, in a possible embodiment, be formed by two independent and opposed plates, each one of them connected to a plate 3' and 3'', for example through bolts 81.

Alternatively, the stopping surface 80 can be an integral part of the plates. In each case, a sliding space is created for a vertical blade 85 with up-down translation motion as shown in figure 5 and comprised between the front plate 3' and the back plate 3' ' . In particular, the blade is connected as well to a blade- holder 86 actuated through a vertical jack 90. The blade- holder 86 and the blade 85 slide inside vertical guides 87.

Figure 4 shows, for example, the case wherein all the three blades (85, 70) have been extracted in such a way as to make a cut of the diameter of the pipe. Figure 4 in fact shows how, in such an extracted position, the blades occupy the circular area defined by the block clamps (10, 15) and the stopping surface 80.

In figure 6 all the pipelines of the oil in pressure for the actuation of said jacks are visible.

Just as a way of example, and therefore not in a limiting manner, it can be indicated that the hydraulic jacks (60, 90) that activate the blades exert a pressure variable within a range from 300 to 350 bar, in such a way as to operate a cut of a steel pipeline of 15mm of thickness and 36 inches of diameter in about 20 sec.

The jacks 50 that activate the clamps (10, 15) exert preferably a pressure around the 300 bar.

Always the same equipment 1, as shown in the attached figures, can be applied to ordinary excavators, cranes or similar machinery, and through which to lean and activate it on the pipe to operate the cut.

In this way, once the cut has taken place, the clamps (10, 15) remain closed to allow the lift and the removal of the portion of cut pipeline.

Having structurally described the invention, for clarity purposes, we pass now onto a description of how it functions.

Initially, the clamps 10 and 15 are open with the blades retracted as per figure 1.

When a cut has to be operate, the equipment 1 is leant on the pipeline with the clamps widened in such a way that the stop 80 leans well on the back of the pipe, as better shown in figure 1.

The cut is then made by closing the clamps and activating the blades until bringing them in the rotated position as per figure 4 (in figure 4 the pipe is not inserted just for descriptive clarity) .

Last, the lift of the cut portion can take place, maintaining the clamps closed as per figure 6.

Although the present equipment, in the preferred embodiment of the invention, has been described with three blades, it is clear that the same could anyway function with a single blade (for example the only vertical blade 85) as also with its only two lateral blades.

Alternatively, also four or more blades could be arranged.

The symmetry with respect to the plane 65 allows in fact the application of four clamps opposed between them but, however, it is clear that also only two clamps would be anyway suitable for realizing a functional equipment.