FI74790B - FOERFARANDE OCH ANORDNING FOER BEGRAENSANDE ELLER STOPPANDE AV ETT LAECKAGE. - Google Patents

Description

! 74790

Method and apparatus for limiting or stopping leakage

The invention relates to a method for reducing or stopping leakage of flowing medium into and / or out of a fluid line, such as an oil or gas line or an oil or gas channel, e.g. in a structure such as a Ö -filled electric cable, using at least a flow transducer 10 change the flow path of the flowing medium. The invention also relates to a flow path reverser with which this method is implemented.

The subject is limited to pipes or conduits filled with a fluid having approximately the same pressure, at least after a leak, as the ambient pressure, and to situations where the self-weight of the fluid inside and outside the pipe or conduit is slightly different.

Po. in particular, the invention relates to a method and apparatus for use with an electric cable impregnated with a fluid, but is not limited to this application. Po. the fluid line does not necessarily have to be included in the electric cable, but may be included in another structure for a different purpose, or it may be a structure whose main function is to conduct the fluid.

Previously known are electrical cables, the insulation of which comprises helically fastened strips impregnated with an oil or gas having a low viscosity 30, e.g. SFg, which penetrates through all the strip layers. The impregnant is allowed to run axially through the cable to avoid the formation of cavities when the cable is exposed to temperature changes, which would cause the fluid to expand / contract.

Assuming that the invention is used with a single conductor cable, the fluid conductor or conductors are usually disposed along the center axis of the centrally disposed conductor 2,74790, possibly in recesses or channels along the inner surface of the outer sheath. If, on the other hand, a multi-conductor cable is used, the fluid conductors are usually intermediate spaces formed between the conductors and between the conductors and the outer sheath.

If such cables, when submerged in the sea, are subjected to externally acting mechanical stress, eg by ship anchors or fishing gear, they may be so badly damaged that the impregnating agent 10 leaks out, causing water to penetrate the cable and replace the lost, running agent. This is, of course, destructive to the cable and contamination from the escaping impregnant can also damage nature. In the worst case, the cable may break completely, leaving two damaged cable ends in the water and discharging a fluid impregnating agent, e.g. oil, out into the water. In this case, the entire part of the cable that has entered the seawater must be replaced. In a conventional cable structure, it has been possible to avoid the ingress of water through the cable ends before lifting the cable ends by means of a certain overpressure in the cable relative to the external water pressure. However, such methods increase gas or oil pollution and incur high costs, while large amounts of oil must be available at cable terminals.

Previously, a device known as a barrier is known which is placed in an underwater cable at certain intervals. This device reduces the amount of oil flowing out during the damage period. Such restrictors are known from U.S. Patent No. 3,793,345, which corresponds to NO Patent No. 134,475. Such known stops must be placed in the cable every several hundred meters. The principle of these limiters is that the penetrating water forms small droplets and their maximum size is determined by the surface tensions between the water and the oil. The small opening in the restrictor thus stops the water, but allows the passage of oil, the properties of the oil and water being determined solely by the size of the hole in the restrictor.

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However, it is clear that such known restrictors do not represent any completely tight barrier against water intrusion if the flow rate is zero, i. if the external and internal pressures are the same at the point of damage.

5 If the cable is immersed in water and the damage occurs at a point where the cable is horizontal, water will slowly penetrate the cable and fill the parts below, while forcing the oil out. The reason for this, of course, is that the specific gravity of water is greater than that of oil (or gas).

10 When the surface of the water reaches an opening in the restrictor, the diameter of which according to said U.S. patent is 4-12 mm, the water hardly forms droplets, but its surface gradually rises until the water flows through the opening and passes the restrictor, which then forms no barrier 15 against the constant intrusion of water. And if the cable is in a more or less vertical position, the water will even more easily bypass such stops.

In order for such previously known restrictors to work satisfactorily, there must therefore be a strong outflow of oil 20 from the restrictor. This flow must be so rapid that it develops a pressure which at least balances the difference between the specific weights of water and oil at the cross-sections of the restrictor. Because the specific gravity of the oil is less than the water, the pressure due to the specific gravity of the oil is less than the pressure due to the specific gravity of the water at the same depth, and the pressure difference must be provided by a pumping station or pressure vessel and stored large to prevent can go to troubleshooting-30 as well as lifting and repairing the cable.

It is also known to place tubular sections around the cable at mutual intervals to limit the ingress of water along the oil channels. For these, reference is made to GB Patent No. 1, 435,592 (corresponding to NO Patent No. 35, 136,866). However, the solution proposed in this patent only works if the cable system is rectilinear and is very close to a completely horizontal position. There need only be small, local irregularities on the seabed to render the measures of this patent ineffective. And the evenly sloping seabed makes the entire line of 5 such tubular sections ineffective.

It can also be mentioned that as soon as the cable has to be lifted and its end is therefore raised towards sea level, the water which has entered the cable with such tubular parts and has already flowed into the nearest tubular part 10 continues to flow freely down the cable core. The tubular parts form even less barriers against the continuous penetration of water when the cable is vertical.

Po. It is an object of the invention to provide a method 15 and a device (hereinafter referred to as a water barrier) which form a barrier to the penetration of water (or other liquid) even when the pressure is the same on both sides of the water barrier, i. when there is no flow, and which also operate other than in one particular position or orientation of the cable, pipe, or line. It is also an object of the preferred embodiment to develop a water barrier having the same water barrier effect regardless of the orientation of the cable itself in the space. In addition, po. it is an object of the invention to provide a method and apparatus which are both independent of the slope and irregularities of the seabed. In addition, the aim is to develop a method and a device that still works when lifting the cable, i.e. when the cable shaft is turned. It is a further object of a preferred embodiment to develop a cable which has the above-mentioned advantages without having a larger diameter or without external aids.

All these objects and advantages are realized by using the methods or apparatus defined in the appended claims.

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Po. In order to facilitate the understanding of the invention and to avoid misunderstandings, various embodiments thereof will be described below with reference to the accompanying drawings, in which: Fig. 1 shows po. the principle of the invention is applied to tuna po. in a simple two-level water barrier according to the invention; Fig. 2 shows an embodiment operating in all possible angular positions of the cable; Fig. 3 shows an arrangement which, in addition to the two-level embodiment, forms an effective watertight barrier against the continuous penetration of water when the shaft of the pipe is turned; and Figure 4 shows a watertight operating in all directions (omnidirectional) in the form of a tubular node.

The solutions according to Figures 1-4 can be formed as internal devices which are placed in a line or pipe, but they can also be formed by placing 20 the whole pipe or line along a curved line, possibly supported by external structures.

Figure 5 shows a practical, helical watertight operating on the same principle as in Figure 2; Fig. 6 shows a cross-sectional view of a slightly different modification of the helical watertight of Fig. 5; Figure 7 shows a maze transformation of a multilevel water barrier; Fig. 8 shows a streamlined shape of a helical watertight provided by a torpedo-shaped core with relatively low resistance to flow-through; Fig. 9 shows a special modification of the maze shape operating in all directions; Fig. 10 shows a special shape of the guide walls of the Torpedo water barrier according to Fig. 8, disassembled in the form of Fig. 6,74790; Fig. 11 shows different forms of possible arrangements in a multi-conductor cable; and Figure 12 shows a water barrier constructed of modules, with each different module substantially reversing the flow path in one plane.

Po. the principle of the invention is to use the reversal of the flow paths in the same way as in a standard water trap. That is, the flow must be directed so that different height levels must be bypassed in the flow of each particle, or more precisely: each particle in the flow must be forcibly moved to a higher level and then to a lower level, or vice versa. It should not be possible for any particle to pass po. through the water-15 barrier of the invention without its height level changing twice, each time in the opposite direction.

Figures 1-4 show a few principles for water traps, all of which act as water traps in more than one position of a pipe or conduit. Figures 1a, b and 20c show a simple two-level watertight or water trap from three different perspectives. Figure 1a shows the front of the water barrier, Figure Ib the top and Figure le the end surface of the same water barrier.

Here, the number 1 indicates a pipe or line that conducts a flow of 25 fluids, 2 and 3 indicate turns in the water barrier in two different planes, 4 indicates a break or damage in the pipe, 5 oil (or other fluid) in the line, 6 infiltrating water (or other fluid) environment, etc.). In the following, ni-30 measurements of water and oil are often used, as these are most often the case. However, the invention can be used for all other fluids as long as there is a slight difference in specific gravity.

If a line or pipe having such a structure 35 is lowered to the seabed, the second curved pipe section, part 2 or 3, tends to be located upwards due to contact li 7 74790 against the seabed. The upwardly pointing pipe section acts as a water trap, while the second curvature is insignificant. If the curved part 2 points upwards as shown, then the penetrating water 6 passes at the water surface 5 close to the shown height 7. If the pressure of the penetrating liquid is now the same as the pressure of the internal liquid 5 in the pipe, the penetrating liquid is effectively stopped at this point. If the pressure of the internal fluid 5 exceeds the pressure of the penetrating fluid 6, a small outflow of the internal fluid 10 occurs at the point of damage, but the penetrating fluid does not move above the level shown 7.

And the entire left part of line 1, i.e. all those parts of the line or pipe to the left of the water trap or barrier are effectively protected against intrusive water. 15 Only if the pressure of the internal liquid or other fluid 5 is so much higher than that of the penetrating fluid that the height of the curved part 2 or possibly 3 becomes smoothed, can the water bypass the barrier and penetrate the left part of the line. Therefore, the internal pressure 20 must be kept at least equal to the external pressure and must be adjusted so that it never falls below the value of the external pressure.

The effect of this watertight is greatest when the slope of the two dashed lines 10,11 is the same in opposite directions. If the pipe or line is tilted so much that the second dashed line is horizontal or both lines are inclined in the same direction, the water trap effect is no longer achieved (the dashed lines practically represent the flow line closest to the straight line).

30 The implementation shown in Figure 1 is an easy way to implement po. invention. A water barrier having this structure has the greatest water-stopping effect at two different angular positions of the pipe or line, namely in the two directions obtained when either curve 2 or curve 3 points straight upwards.

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Figure Id shows another implementation. Here are placed small plates 12,13,14,15 which partially fill the cross-section of the pipe. The angular positions of these plates are shown and are all different. The plates thus force the current 5 to make up / down and right / left movements inside the tube.

Yet another solution is shown in Figure 2. Here Figure 2a shows the structure from the end face and Figure 2b shows it from the side. The tubes are made in the form of a helix-10, with the exception of the ends 8,9 which are introduced in towards the axis of the helix. However, the ends can also be placed along the circumference so that the watertight takes on a helical shape from one end to the other. The effect of the water barrier does not have two clearly different maximum values here, but its value 15 is approximately the same regardless of the angular direction in which the helix is rotated about its own axis. Such a water barrier therefore acts as a water barrier even if there is no separation pressure. The only condition is that the helix must be substantially horizontal or in any case within the limits defined above in connection with the dashed lines 10,11 of the embodiment of Figure 1.

It is now clear that the same watertight effect can be achieved both when the entire fluid line 25 or pipe is curved and when the shown interior is placed in the flow path of the pipe, so that the flow path is only inverted within the relatively small dimensions constrained by the fluid itself. the dimensions of the channel conducting the substance. Thus, the oil flow path 1 in Figure 1 may either represent the entire pipe or channel 30 that has been lowered, or a small, limited portion of the oil channel. In the latter case, the curves up / down and to the right / left must be performed within relatively narrow limits, depending on the dimensions of the oil channel itself. Of course, multiple parallel flow-35 devices can be used instead of just one flow path.

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It is now clear that such a structure, when subjected to infiltrating water, forms an effective barrier against the continuous ingress of water when the pressures are the same. In such cases, no fluid flow is required at all. Thus, the environment does not have to be polluted.

However, there is a drawback to the implementation of both Figure 1 and Figure 2. If the other end of the watertight barrier is raised so much that the dashed lines 10,11 settle horizontally-10, or even tilt in a direction other than that shown in the figures, then the device loses its watertight operation. If the water barrier according to Figure 1 or 2 is placed in a pipe or pipe lowered to the seabed, then the water that has entered the line to the right side of the water barrier 15 passes directly through the water barrier as soon as the right side is raised to a slope greater than described above. In such structures, the pressure of the oil, i.e. the flow of fluid, increases considerably during the uptake, because a strong flow of oil 20 is required to prevent the continuous penetration of water. However, even this solution is included in po. within the scope of the invention, since an outward flow of oil is only required during a relatively short uptake, but is not required during the preparation for lifting the end of the pipe, e.g. during localization 25 and the like.

To ensure that the watertightness function is maintained even when turned from horizontal to vertical and then back to horizontal, the bent part must have a bend of at least 270 °. This is because the 30 static watertight must make a 180 ° bend, but the horizontal-straight / vertical / horizontal rotation that occurs during pipe lifting represents a 90 ° increase.

Figure 3 shows a solution with a 360 ° bend in the pipe, and this therefore effectively protects against the ingress of water 35 during turning, e.g. when lifting the pipe, and by more than 90 °. If a single-level water barrier is sufficient, LarviLaan 10 74790 only one bend, such as 16 or 17. Therefore, a pipe with only one such bend is also covered by po. within the scope of the invention. However, even in this case, a two-level watertight can be easily obtained, as shown in Fig. 3a 5 from the front, Fig. 3b from above and Fig. 3c from the side.

With a relatively simple arrangement, it is also possible to obtain a watertight effect which works in all directions, i. a watertight that works in the same way regardless of which direction in the space or angular position the put-10 is given to. Figure 4 shows, for example, a pipe to which a node structure has been given. Regardless of the direction in which such a simple node is viewed, it always has a 360 ° bend. Thus, a fluid line or pipe formed into such a simple node forms an effective watertight barrier acting in all directions. If such water seals are to be made in the form of stoppers placed in the fluid line, a smaller, tubular part arranged as shown can be cast e.g. in a closed body with only an opening in at least one channel as shown. The molded or otherwise made interior may have external dimensions that are precisely matched to the internal dimensions of the pipe itself. Such a solution is shown as a transparent body in Figure 4c.

25 Alternatively, an external, stiffening structure may be used to maintain the desired shape of the entire tube. Such an external structure may be molded or shaped into a rigid frame. If the pipe is sufficiently flexible and pressure-resistant, e.g. the shape shown in Fig. 4 can possibly survive without external support, because the structure itself is sufficiently rigid. In many cases, however, the pipe or wire is so rigid that the node must be relatively open, in which case it is preferably supported by external means.

35 The principles shown in Figures 1 to 4 can be implemented in different ways, of which different implementations are shown in Figures 5 to 13, but several similar solutions can be implemented.

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n 74790 may be used in accordance with the principles shown above. The only important point is that the arrangement must be such that it forces the flow in different varying directions in order. For example, a helically braided strip having a width corresponding to the diameter of the channel can be inserted into the channel, and in many cases this provides a sufficient change of direction to obtain the desired effect (not shown).

In Figure 5, it is thought that the watertight is shaped internally, which can be placed at intervals in a circular oil channel. The inserted water seals 20 may be metal, an artificial material such as plastic, rubber, etc. The shape is simply a substantially cylindrical body with helical grooves 21,22,23 on the outer surface. The thickness L of the body 20 and the pitch of the helical grooves 21, 22 and 23 can be determined independently of each other so as to obtain more than one bend in each helical recess or recess. The recommended value is about 1.5 bends, ie 1.5 x the revolution length of the recesses.

20 Since the recesses or grooves 21,22,23 are open to the environment, it is a prerequisite that the inner is placed inside a smooth-walled cable which is adapted to the inner according to the external shape and size. The depth of the grooves 21,22,23 together with the rotational length 25 of the helical shape of the grooves determine the maximum permissible inclination at which the pipe or oil line can be without this affecting the degrading internal water trap effect. This has already been explained in connection with Figures 1 and 2. (Reference is made here to the slope of the dashed lines 10.11).

30 The following table gives the results obtained in the test performed po. according to the invention with different dimensions.

Koe I Koe II Koe III

n Number of grooves 334 D Inside diameter (nm) 30 30 30 3 5 S Groove rotation length (nm) 72 75 140 L Inner length (nm) 108 112 210 d Equivalent diameter (nm) groove 9.5 7.1 9.1 ^ per 1 ^ The flow resistance corresponds to an additional 6.0 19.1 7.1 channel length (m) 12 74 79 0 This test includes e.g. found that a water barrier with a length of 112 mm, a diameter of 30 mm and 3 grooves, each with an equivalent diameter of 7.1 mm, while a rotational length of 75 mm, provides an additional resistance against 5 flow-throughs, representing the same as the oil channel. van 19.1 m additional length with the same diameter as the inside, i.e., 30 mm diameter, where d 2 d _ 4 eq

io eq 7 "· d ja] k- 1F 'L

where d is the measured groove depth in mm.

In addition, the flow resistance that comes with each such internal can be critical because the total flow resistance in the channel must be within certain limits in order for the oil supply to each point along the saturated electrical cable to be sufficient to compensate for temperature variations.

If the inner surface of the cable is not completely smooth, the implementation according to Figure 6 can be considered the best. Here, the helical grooves 20 or openings along the inside are not open at the surface. This makes it easier to seal the inside and between the inner surface of the cable using a sealing compound or gasket. The helical openings 21 ', 22', 23 'may have a circular cross-section or the shape 25 shown in Figure 6 and do not extend as far radially as in the circumferential direction. In such a variation, which uses a relatively small radial dimension or depth in each channel, the water barrier effect increases slightly, as mentioned in connection with the description 30 of the dashed lines 10,11 in Figures 1 and 2.

The implementations of Figures 5 and 6 achieve a watertight effect at all angular positions of the pipe or cable, but if the slope increases much, then the watertight effect decreases and eventually is completely lost, as explained above. However, if transfers are made

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13 74790 from one groove to another, e.g. a pipe connection between the channel 21 and 22 on the inner left side and from the channel 22 on the inner right side of the channel 23, a reciprocating movement of the fluid is provided in addition to the helical movement.

5 The fluid then has the following flow path: the left side of the channel 23 to the right side of the channel 23, back to the left side of the channel 22 and out of the right side of the channel 21 (or vice versa). With such an externally or internally arranged return path, a watertight effect independent of the direction (all-way) is achieved, also with this structure.

Another solution is shown in Figure 7. This transformation can be called the maze method. Here, the stream of fluid 15 is passed through a spacious maze as shown.

Figure 7 shows a very simple example with three labyrinth compartments and partitions with visible openings 24,25,26 and 27. The current then enters through these openings in sequence and is forced to turn in different 20 directions. In this way, the direction of the flow changes so often that a watertight effect is obtained regardless of the direction of the barrier in the space. This is the so-called omnidirectional watertight.

The solution shown in Figure 8 is basically the same as in Figures 2 and 5, as the flow paths have a similar shape. The watertight inserted here comprises a centrally located, closed body 30 with protruding wings 31, 32, 33, 34. The number of protruding wings is not essential and can be selected. to fit structure 30. The vanes are made helical as shown in the figure and the pitch of the helices can vary gradually along the water barrier to ensure a uniform and laminar flow space. The direction of rotation of the wings is preferably the same as the direction of rotation of the inside of the cable if a twisted wire is used. The rotational length of the wings at the beginning and end of the watertight can be the same as the rotational length of the inner layer of the line.

14 74 79 0

The centered, closed body may have a torpedo shape as shown, thereby creating a low flow resistance and further allowing a certain tilt of the tube.

5 A special solution based on this principle is a simple, light but rigid piece of tape twisted longitudinally and placed in a duct.

The thickness of this strip determines the minimum allowable height or height change of the flow lines. The strip placement is then inserted in each cross section along the diameter of the channel. The strip is just as wide as the diameter of the channel. In addition, a twisted, inserted part having a polygonal cross-sectional shape can be used, since in this case too narrow channels 15 are provided between the side surfaces of the polygon and the wall of the channel. Alternatively, the channels can be provided between a round, cylindrical interior and the wall of the channel itself, if the latter is corrugated or shaped with otherwise helical grooves.

Figure 9 shows an even more complex implementation, which is also the above-mentioned maze model. However, if only one vane is used, a flow path similar to that in Figure 4 is obtained here. This water barrier entry point is assumed to be located at the upper end. In this case, the flow enters from the inlet 35 and passes axially through the semi-cylindrical shape 25 through its tube 36. Below this tube, the flow passes outwards through openings in the tube wall, as indicated by arrows 37, and through the collector space 43 or possibly separate chambers if several vanes are used, passes to one or possibly several parallel and helical tracks 38 (only one shown in the figure) surrounding middle cylinder, and back to the upper end 39. A closing flange is placed at the upper end and the flow must turn again, this time according to the arrows 40 inwards into the second semicircular tube 41, which is complemented 35 with the first semicircular tube 36, and then runs axially lower.

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is 74790 towards exit 42. This space maze is placed in the oil channel or transmission channel of the cable and forms a water barrier that operates regardless of the installation direction. The outer surface 44 may be a dense, cylindrical wall, but this may also be omitted because the inner surface of the flow passage or fluid line acts as such a dense cylinder itself. The common cross-section of all the cylindrical grooves 38 may be equal to the cross-sectional area of each semi-differential shaped channel 35,42. In this case, the cross-sectional area of the flow 10 is approximately one third of the total cross-section of the line.

Fig. 10 shows an expanded form of the maze, i.e. it shows a bottom view showing the shape of the protruding wings 15 of the torpedo water barrier shown in Fig. 8. Here, the wall of the pipe or the duct itself is used as part of the wall of the maze or as part of its outer sheath. Here again, the shape of the partitions can be arranged freely, and although a purely helical arrangement is proposed in Fig. 8, a more complex arrangement is proposed in Fig. 10, which gives a watertight effect in all directions. The length dimensions of compartments A and B can be chosen relatively freely, but are preferably at least equal to the diameter of the duct to obtain the same good water barrier effect as in other implementations.

25 if po. the principle of the invention is applied to a conventional three-phase, oil-impregnated three-conductor cable, one of the various implementations of Figure 11 may be used. Here, the numbers 45, 46 and 47 indicate three round, insulated conductors placed in an impermeable sheath. Insulated conductors are usually placed helically. This forms four helical channels in which oil can be transferred inside the walls of the cable sheath. The three outer channels 49,50,51 have the same cross-section, but the central channel 52 is substantially 35 smaller and its axis is straight, but this is also helically twisted.

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If the central channel is now closed locally at a suitable distance from each other, the transfer of oil along these cable sections must take place entirely through helical, similar circumferential channels, thus simply achieving the same effect as in the variant of Figure 2, except that three helical parallel channels are obtained. through the local watertight area.

In order to improve the water barrier effect, the inner part of the helical channels at the circumference can also be filled. Figure 11b shows a suitable form of filling device 53 with which the desired effect is achieved. In this case, the varying upward and downward movements of all the parts involved in the flow receive a much greater height variation, as a result of which the efficiency of the water barrier is better. As a result, a landing path with a higher slope can be used. Conversions can, of course, be made. Thus, reversers or water barriers, as mentioned above, can be built into each channel, or the channels can be partially filled with a suitable, filling body. Reference is also made here to Figure 11c. In a multi-conductor cable, the twist length affects the effect of the allowable tilt angle in the same way as the twist length of the coil affects the allowable tilt angle in Figure 2. Therefore, the twist length can be reduced locally 25 or along the entire cable. A turning device according to any of the above-mentioned solutions can be placed in the holes 54,55,56 of the filling device of Fig. 11c. If these filling devices 53 or seals are made of elastomer, the water seals that may be placed in the holes 54,55,56 may be metal-30 to counteract any expansion forces that may occur. Also in these embodiments, two separate filling devices with a short axial dimension can be used, between which a watertight is placed, as well as the watertight according to Fig. 4 can be made in the form of a knotted pipe piece 35 - with flanges on both sides instead of a cast pipe piece.

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If the insulation is too dense to allow sufficient oil flow into and out of the duct, which oil flow is in the middle between the duct sealing parts, a lower flow path can be placed between the central duct and one of the other 5 circumferential ducts, between the filling devices. For example, a small flow connection between the center line and a special circumferential channel can be placed at axially spaced intervals. If these small radial flow paths are spaced so that they are all parallel, in the same plane, and connected to the same circumferential channel, there is no danger that the central channel will establish a parallel connection to the water level below the level in the same helical circumferential channel.

15 Po. various modifications can be made to the invention with many different structures. Thus, the water-barrier effect can be in only one plane, two perpendicular planes, or three orthogonal planes. More than one flow path can be used.

The structure according to Figure 2 can be obtained by attaching straight pipe pieces to the between the two flanges arranged according to the channel and then by turning the unit, possibly using a spacer in the middle to avoid internal bending points in the pipes when these are helically threaded. The substance may be conductive, e.g. metal, or insulating, e.g. plastic. To reduce the flow resistance, each opening may have a streamlined inlet and outlet zone as shown in Figure 4c. The helical blades 30 of the torpedo-shaped body of Figure 8 may also have a slowly or gradually varying pitch to reduce the risk of eddy current.

In Figure 12, it is assumed that po. the watertight of the invention can be constructed of modules. For example, each module 57,58 can reverse the flow path in only one plane (or two 35 planes 59). When the modules are assembled into an effective watertight, the mutual arrangement ensures that a multi-way or omnidirectional watertight is achieved. In Fig. 12, the module 58 18 74790 reverses the flow horizontally, the module 57 vertically, while the module 59 takes care of the vertical change of direction in connection with the tilting effect.

The assembly of these modules, in which each module forms a reverser in one plane, therefore forms a combined reverser which acts in all directions.

With respect to the flow field, it is assumed to be advantageous that the cross-section of the flow paths is constant throughout the direction-10 converter. This is achieved, for example, in the implementation of Figure 9, if the cross-sectional area of the semi-cylindrical flow paths 36, 42 is equal to the sum of the helical parallel channels 38.

In addition, the entire cable or transmission channel may be curved and attached to an external support device to maintain its shape. This external device can be placed under the cable on the seabed or on the ground to lay the cable, or it can be attached to the cable and lowered at the same time.

20 Other solutions are also conceivable po. within the scope of the invention. For example, prefabricated reversers can be installed in the cable oil duct during cable fabrication, or they can be connected to the cable at each regular cable connection.

25 Several reversal principles can also be used in one and the same water barrier.

In large plants, it is also possible to enclose the cable or pipe, at least at reversal or turning points, in a drying pipe system where a lower pressure can possibly be maintained. In this case, the harmful fluid can be discharged at each turning point and taken out via a drying system. With such a drainage system, possible leaks can be monitored continuously.

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The plant can preferably be equipped with a system to provide pressure equalization or to obtain a small oil overpressure at the break points. However, this does not belong to po. to the invention, so this will not be described in more detail.

However, it is necessary to mention po. a particular application of the invention to explain the fact that a change of direction is also useful in a high pressure plant.

If po. the reversal according to the invention is used at mutual intervals in an underwater oil pipe with a high pressure, the amount of oil leaking out due to rupture in the pipe system can be considerably reduced. If the oil supply is stopped as soon as a rupture is detected, then the large amount of oil that remains in the pipe-15 sections inside the water barriers will remain here and there will be no contamination between it and the water. Therefore, it is also possible to reduce the outflow and contamination caused by the outflowing oil as well as the oil losses. As for the electric cable, the cable damage is also reduced, because the water penetrating the cable cannot enter between the reversing or turning devices.

Claims (13)

20 7 4 7 9 0 A method of reducing or stopping leakage of flowing medium into and / or out of a fluid line, such as an oil or gas line or oil or gas channel, e.g., in a structure such as an oil-filled electric cable, using at least a flow transducer that locally changes the flow a flow path of the medium, characterized in that a plurality of flow path deflectors are used, each of which is designed to force or direct each portion of the flowing medium to change its height position at least twice in a different direction as it passes through the flow changer. A method according to claim 1, characterized in that the flow path transducers reverse the flow of fluid in different directions so as to provide a water trap effect in at least two different orientations, different angular orientations or different axial orientations of the line, and preferably in each of its positional orientations. Method according to claim 1 or 2, characterized in that the flow path transducers rotate the flow path so that the projection of the flow path 25 rotates by at least 180 ° and preferably 360 ° in at least one projection plane and preferably in three orthogonally arranged projection planes. A flow path converter for carrying out the method according to claim 1, 2 or 3, characterized in that it is a water trap with a plurality of curved parts having a maximum water trap effect in at least two different flow path directions. A reversing device according to claim 4, characterized in that it comprises one or more curved openings or holes (21 ', 22', 23 ') arranged in an otherwise closed body, and / or one or more a curved recess (21, 22, 23) disposed along the surface of the otherwise closed body (20). A reversing device according to claim 4 or 5, characterized in that it comprises a torpedo-shaped body (Fig. 8) arranged in the middle of the fluid line and fastened thereto by outwardly projecting vanes (31, 32, 33, 34) which is preferably placed in a regular shape. Reversing device according to Claim 4 or 5, characterized in that it comprises a maze constructed of plates (12, 13, 14, 15) and / or partitions with holes (24, 25, 26, 27, Fig. 7) which direct the flow of flexible material in different directions in space. Reversing device according to Claim 4, characterized in that the fluid line itself is laid on a predetermined, curved path, which is preferably guided and supported by a rigid external structure. A change of direction according to claim 4, 5, 7 or 8, characterized in that the flow path comprises at least one peripherally arranged, cylindrical and helical path, preferably comprising a bend of at least 110 °, and that this (these) the entry point (s) / exit point (s) of the helical track (s) are arranged axially through the axes of the helix or helixes and preferably in a crosswise manner so as to achieve a structure established on a common track (Figure 4). A reversing device according to claim 4, 5 or 9, characterized in that it comprises one or more tubes or hoses which are either curved or twisted in a predetermined manner, after which they undergo an injection so that the tubes are formed 22 7 4 7 9 0 provide flow openings in an otherwise closed body (Figure 4a). A reversing device according to claim 4, 5, 6, 7, 8, 9 or 10 for use in a multi-conductor cable having an insulating fluid flowing in a free space between the conductors and / or between the conductors and the outer sheath, characterized in that that at least the central channel or channels (52) between the conductors are filled locally or throughout with a closing material (53), while all or some of the circumferential channels between the conductors and the outer sheath are at least partially open and form reversible flow paths. A reversing device according to claim 11, characterized in that the reversing device according to any one of claims 4 to 10 is arranged in a sealed manner in at least one circumferential channel (e.g. at positions 54, 55, 56). A reversing device according to any one of claims 4 to 12, characterized in that its track is formed or stiffened by a supporting structure which is so rigid that it substantially retains its shape under normal handling and workloads. Il 23 74790 Patentkravet