**** DESCRIPTION The present invention concerns a pipe fitting with automatic release and immediate water seal closing in response to a strong axial traction.

Pipe fittings, used particularly in oil field for the coupling of flexible pipes in movement, for example between ship and ship, ship and land, ship and oil offshore rig, in which it is expected that possible strong axial traction stresses due to causes of any kind would automatically provoke the release of the fitting and the immediate intercepting of the hydraulic flow under course are already known. In this way it is possible to prevent that an axial traction above a maximum limit bearable by the flexible pipes would determine the deterioration of the same pipe.

Object of the present invention is to provide a fitting of the aforementioned type, that in case of automatic release due to axial traction above a maximum limit would provide a particularly efficient simultaneous water seal closing.

According to the invention, such object is attained with a fitting realised into two parts passed through by respective axial ducts for a flow of fluid and provided with means for the rigid coupling of said parts that are formed in such a way so as to allow the automatic separation of the same parts in case of an axial traction above a predetermined limit, at least one of said fitting parts comprising a means for the interception of the flow of fluid that is automatically activated up to a water seal closing position by the separation movement of said fitting parts, characterised in that said means for the interception of the flow of fluid consists in a ball segment valve that responds to that separation movement with a combined motion of rotation around an axis perpendicular to the longitudinal axis of the respective fluid duct and of sliding along said longitudinal axis until it reaches a forced rest

and water seal position against a seal packing.

In this way the release of the two parts of the fitting, and therefore of the two parts of pipe coupled by the fitting itself, in the instance of a particularly high and dangerous axial traction stress is automatically driven by a movement of the ball segment valve, which not only causes its rotation from an opening position to a closing position but it also gives it a forced axial engagement against a seal packing, that ensures a perfect water seal and therefore prevents undesirable wastes of product.

A few embodiments of the present invention are illustrated as a non- limiting example in the enclosed drawings, in which: Figure 1 shows in an axial section a single valve embodiment of the fitting according to the present invention, in an operating position; Figure 2 shows the aforementioned fitting in a cross section according to the line II-II of Figure 1; Figure 3 shows the same fitting in a cross section according to the line III-III of Figure 1; Figure 4 shows the same fitting in a longitudinal section according to the line IV-IV of Figure 1; Figure 5 shows a magnified detail of the fitting of the previous figures; Figure 6 shows the fitting of Figure 1 in the release and water seal position; Figure 7 shows the fitting. of Figure 1 at the beginning of the release stage in case of a not exactly axial traction; Figure 8 shows in an axial section a two valve embodiment of the fitting according to the invention, in an operating position; Figure 9 shows the fitting of Figure 8 in a release and water seal positions.

The pipe fitting illustrated in Figures 1-7 is of the single valve type and it comprises a first and a second part 1 and 2 that are fixable to each other by means of a circumferencial series of break screws 3 having a intermediate

length 4 with reduced, or weakened, section (Figure 1).

The first part 1 of the fitting comprises a first an a second annular flange 5 and 6, the first one of which is fixable by means of screws 7 to a first part of pipe 8, more precisely the one destined to deliver fluid. From the same flange 5, in coincidence with its central hole 9, a cylindrical duct 10 defining an axial passage for the flow of fluid that goes through the fitting extends in the opposite direction but axially lined up with the part of the fitting 8.

Coaxial to the duct 10 and outside of it a cylindrical coupling box 12 that ends as fixed by screws 13 in correspondence of the flange 6, still extends from the flange 5, to which it is fixed by means of screws 11.

In the annular space 14 defined between the duct 10 and the coupling box 12 a disc 15 sliding in axial direction is housed, that is thrust toward the right (looking at Figure 1) by a pressure spring 16, that is possibly replaceable by several springs coaxial to each other.

Two rack rods 17 (Figures 1,2 and 4) slidingly sustained by a pair of supports 18 fixed inside the coupling box 12 are symmetrically fixed to the sliding disc 15. In addition, respective toothed segments 19 are fixed to the same supports 18, in a position opposite to the rack rods 17.

Each rack rod 17 ends with a piston 20 slidingly housed inside a respective cylinder 21 that is fixed to the flange 6. The cylinder 21 is normally filled with oil that is not in pressure, that in case of backing of the piston 20 as regards the position of Figure 1 can outflow at a controlled speed through a gauged hole 31 (Figure 1), as it will be better explained further on.

Between each rack rod 17 and the corresponding toothed segment 19 and a in toothed engagement with them a gear wheel 22 is arranged, which as caused by the aforementioned engagement is capable to rotate around its axes, perpendicular to the longitudinal axes of the duct 10 and of the coupling box 12 and passing through it, and to slide parallel to the same longitudinal axes.

The axes of rotation of the two gear wheels 22 is also the pivot pin of the rotation of a ball segment valve 23 (1/4 of ball in the example illustrated), that is fixed to the same gear wheels and owing to the rotary- sliding movement of the same it can be moved from the opening position illustrated with a solid line in Figure 1 into the closing position illustrated in dots and lines in the same figure. In this latter position of the spherical back surface 24 of the valve is not only rotated perpendicular to the axes of the fitting but also pressed against an annular seal packing 25 fit into a corresponding housing of the flange 6.

The second part 2 of the fitting comprises in turn a cylindrical duct 26, that is of the same diameter of the duct 10 of the first part 1 and it is axially lined up with it in such a way so as to complete the axial passage for the flow of fluid through the fitting. Besides, a short circumferencial interval between the same ones (Figure 1) allows to maintain said axial passage into communication with the previously defined annular space 14.

The cylindrical duct 26 axially extends from the central hole 27 of a flange 28 having reduced external diameter as compared to the flanges 5 and 6 of the first part of the fitting. The corresponding face of the flange 28 is normally fixed to the flange 6 owing to the previously mentioned break screws 3. A second part of the pipe 30, more precisely the one destined to receive the fluid being delivered, is instead fixable to the other face of the same flange 28 by means of screws 29.

Because of the described structure, the normal operating state of the fitting is the one illustrated in Figure 1, where the break screws 3 keep together the two fitting parts 1 and 2 and therefore the two pipe parts 8 and 30, the valve 23 is open and it is maintained like that by its contrasting with the wall of the cylindrical duct 26 and the delivered fluid can pass from the first pipe part 8 to the second pipe part 30 through the axial passage defined by the two lined up cylindrical ducts 10 and 26, without any obstacle.

If in this condition one of the two pipe parts should be subjected to an

axial traction stress above the allowed limit, the weakened parts 4 of the break screws 3 would break, thus allowing the flange 28 of the second part of the fitting to move apart from the flange 6 of the first fitting part (or vice versa). Not being retained by the wall of the duct 26, the valve 23 would start rotating and sliding under the effect of the elastic bias exerted by the spring 16 on the annular disc 15, that in turn would provoke the axial sliding of the two rack rods 17, and in combination with the fixed toothed segments 19, the rotation and the axial movement of the two gear wheels 22 and therefore of the valve 23 with a speed depending on the resistance exerted by the oil inside the cylinder 21 on the piston 20, that is on the speed of the oil outflow from the same cylinder, still that is on the gauging of the gauged hole 31.

The fitting therefore turns out to be in the released and water seal condition that is shown in Figure 6.

It must be noted that the separation of the two parts of the fitting is favoured by the rounded shape of the length of external wall 32 of the duct 26 that through an O-ring 33 is normally water seal coupled with the central hole 34 of the flange 6 (Figure 5). Indeed, such rounding allow the slipping of the duct 26 out of the central hole of the flange 6 even in case of a not perfectly axial stress exerted on the two parts of the fitting (Figure 7).

Conceptually not dissimilar are structure and way in which the fitting with two valves illustrated in Figures 8 and 9 works.

More precisely, the first part 1 of the fitting is absolutely identical, while the second part, herein indicated by 2', is changed.

More precisely, the part 2'has a flange 6'conformed as the flange 6 of the fitting of Figures 1-7 and similarly provided with an annular packing 25', a second flange 5'of equal diameter fixable to the second part of pipe 30 by means of screws 29'and a cylindrical coupling box 12'for the coupling between the flanges 6'and 5', that is fixed to the same flanges by means of screws 13'and 11'. The two set aside flanges 6 and 6'of the two parts of the

fitting are normally kept together by break screws 3.

A cylindrical duct 10'that ends before it reaches the flange 6'and forms in turn a passage for fluid that is lined up with the one defined by the ducts 10 and 26, extends from the flange 5'too toward the flange 6', coaxial to the the coupling box 12'an inside of it.

In the annular space 14'between the duct 10'and the coupling box 12' an annular disc 15'that is elastically biased by a pressure spring 16'is similarly arranged in an axially sliding way.

The disc 15'and the spring 16'control the rotary-sliding movement of a ball segment valve 23'through a mechanism entirely similar to the one already described for the first part of the fitting 1, and precisely comprising sliding racks 17', supports 18', fixed toothed segments 19'and gear wheels 22'with rotary-sliding movement, with the only exception that the rack rods 17'do not end in a piston as piston 20 but they instead slidingly pass through the flange 6'until they end up abutting, when the fitting is coupled, against the flange 6 of the first part of the fitting 1 (Figure 8). Such abutment engagement allows the valve 23'to maintain itself in the opening position illustrated as a solid line in Figure 8 against the elastic strain of the of the spring 16'and possible traction stresses below the prefixed limit.

In case of a traction stress having entity such as to provoke the breaking of the screws 3, the two parts of the fitting move one apart from the other in a way similar to what described for the fitting of figures 1-7 and, being therefore the abutment engagement of the rack rods 17'with the flange 6 lost, the spring 16'can force through the disc 15', the racks 17', the toothed sectors 19'and the gear wheels 22'the rotary-sliding movement of the valve 23'until this engages with its arched back 24'the annular seal packing 25' (Figure 9).