FIELD OF INVENTION The present invention relates to an arrangement for passing one or more cables through a cable-enclosing duct with the aid of liquid under pressure, said liquid consisting of water in the most usual case.

The invention is based on correspondence or at least substan- tial correspondence between the relative density of the liq- uid used and the relative density of the cable, so as to lighten the cable with the intention of facilitating its pas- sage through duct sections which together form a duct run in a duct system.

The invention also relates to such an arrangement in which the liquid pressurised by a pump means is permitted to flow through said duct run as the cable passes through a nozzle and into an upstream located end-part of the duct run, it be- ing known that when the velocity of the liquid passing through the duct is higher than the current or prevailing ve- locity of the cable through the duct, the cable will be in- fluenced by a pulling force that acts along the cable section enclosed by said duct.

BACKGROUND OF THE INVENTION An arrangement of the kind described in the introduction is illustrated and described in European Patent Publication EP- B1-0 665 993, to which reference is made for a deeper under- standing of the fundamental conditions with which the inven- tive features are associated.

The following patent publications are also mentioned with consideration to the characteristics of the present inven- tion.

DE-A1-3140928 This publication describes a method, and a device to perform the method, where the device comprises a duct piece (3), in- sertable into a supply duct (2) and connectable with its con- nections, where the duct piece is supplied with a connection piece (4), which forms an angle of 120° to 160° with the duct axis (5) for an insertion of a cable.

A possibility to insert telephone cables through a water sup- ply net for drinking water is taught here, where a pulling body is allowed to pass to the open duct end of the water supply net by the flowing drinking water.

This publication teaches the use of a seal, which is supposed to sealingly connect, without any movement, to the peripheral surface of the cable, even with applied water duct pressure.

The use of a holder arrangement (9) with a constriction adapted to a smallest cross section for used cable is taught for this purpose, with the instruction that the constriction is to be bored when used with a cable with a larger cross section.

The use of a number. of sealing rings (10,11), positioned on each side of a hole cylinder (12), is also taught.

The sealing material is pressed towards the constriction (9) through bolting in order to form a waterproof connection or closure.

FR-A-681 220 This publication teaches a sealing arrangement, adapted to a duct joint or pipe joint, of a character that is very close to what is taught in the above cited German patent publica- tion.

SUMMARY OF THE INVENTION TECHNICAL PROBLEMS When taking into consideration the technical deliberations that a person skilled in this particular art must make in or- der to provide a solution to one or more technical problems that he/she encounters, it will be seen that it is necessary initially to realise the measures and/or the sequence of measures that must be undertaken to this end on the one hand, and to realise which means is/are required in solving one or more of said problems on the other hand. On this basis, it will be evident that the technical problems listed below are highly relevant to the development of the present invention.

When considering the present state of the art as described above, it will be seen that a technical problem resides in creating conditions which will enable a cable to be fed into a duct run that forms part of a duct system with only low friction between the outer surface of the cable and a nozzle used to this end, while nevertheless providing a satisfactory seal against the penetration of said liquid.

A further technical problem is one of constructing a nozzle that can be included in a first device which is comprised of only a few individual parts, such as two mutually coacting parts, and which does not solely take into account the condi- tions required for friction-reduced movement related passage of cable sections through said first device, but also takes into account required liquid-sealing measures with respect to the pressurised liquid used.

Another technical problem is one of providing in a first de- vice a nozzle with which there can be easily used a readily applied packing arrangement which is adapted so that its packing material can be caused to abut sealingly or essen- tially sealingly against the outer surface of the cable and which can be applied within said parts with a low degree of friction adjustable by said parts for displacement or move- ment of the cable sections through the packing arrangement while the outer surface of the cable sections are lying in abutment with said packing material.

Another technical problem is one of realising the signifi- cance of using packing material in said packing arrangement in the form of yarn, cord, ribbon or the like that is wound around the cable, and to choose the actual packing material <BR> <BR> <BR> <BR> from a material that has pronounced low-friction properties.

With regard to the aforesaid application, another technical problem is one of realising the significance or winding around the cable through one or more turns of packing mate- rial that comprises yarn, cord or ribbon of such elastic properties that when compressed the material will expand transversely to the direction of the pressure forces and therewith seal against the outer surface of the cable.

Another technical problem is one of realising the signifi- cance of using braided yarn as the packing material in this respect.

Another technical problem is one of realising the signifi- cance of choosing the packing material from materials that will have low friction against the cable surface and which will also be strong, such as a yarn of fluoroethylene plas- tic.

Another technical problem is one of designing each of the two mutually coacting parts of the packing arrangement and of choosing the packing material such as to enable the packing arrangement to be applied over a cable section of a cable run located within a duct section, and therewith realising the significance of dividing said mutually coacting parts of said packing arrangement into separate parts, such as into two parts, and to adapt said parts for insertion between mutually adjacent end-parts of a duct section.

In this latter respect, a further technical problem resides in forming said parts so that they can be inserted into each of mutually opposing duct-ends that are formed by removing or exposing the duct section, and thereafter moving said parts into sealing coaction with each against the cable section.

It will also be seen that a technical problem is one of real- ising the significance of and the advantages associated with providing one of said parts with a groove or channel into which the packing material and also an annular portion of the second part can be adjustably inserted.

Another technical problem is one of realising the signifi- cance of first applying the packing material to a cable sec- tion and then causing said packing material to be inserted

between said parts so that said material is fully enclosed and covered by said annual portion.

Another technical problem is one of realising the signifi- cance of and the advantages afforded by using a device or means which enables said parts to be moved towards and away from each other such as to adjust the pressure that acts axi- ally on the packing material so as to obtain an increasing radial sealing effect with slightly increased friction, or vice versa.

When considering the state of the art as described above, it will also be seen that a technical problem resides in provid- ing with the aid of simple means conditions in which one and the same cable can be passed through a first duct section and through a series oriented second duct section that is sepa- rated slightly from said first duct section, without needing to join or splice the cable between said duct sections.

With respect to a packing arrangement of the aforedescribed kind, a further technical problem resides in providing simple means that will enable a cable of small cross-sectional area, or a cable of relatively large cross-sectional area, to be drawn through a duct run.

A further technical problem is one of enabling the use cf one or more sleeves whose cross-sectional areas are selected in relation to the cross-sectional area of the cable and to pro- vide conditions which will enable respective sleeve to take a fixed relationship with mutually adjacent parts with the in- tention of preventing displacement of the sleeve relative to said parts.

When considering the present state of the art as described above, it will also be seen that a technical problem resides in the provision of conditions with the aid of simple means

such as to enable a--cable drawing duct to be increased with respect to a cable length that is far in excess of the length that can be provided by inserting the cable into one end of a duct, or pipe, and there applying liquid pressure.

Another technical problem resides in enabling a duct section to be severed at selected positions beyond which the cable end has passed (with a piston arrangement mounted thereon) and, if required, to be able to remove a short part of a duct section and to fasten to the resultant opposing ends of said duct sections an arrangement which will enable movement of the cable (and the piston arrangement) to be continued, this arrangement being referred to as an"amplifier".

Another technical problem is one of providing with the aid of simple means conditions which will enable one and the same cable to be passed through a first duct section from the up- stream end of said section to its downstream end and from there through a second duct section whi'ch is series-orien- tated and slightly spaced from said first duct section, with- out needing to splice or otherwise join the cable between said duct sections.

Another technical problem resides in providing an arrangement construction which is adapted basically to enable it to be utilised at the furthest upstream end or alternatively at a selected position and modified to provide an"amplifier".

Another technical problem is one of adapting an arrangement so as to enable one and the same piece of equipment to be used with each duct section and, after making necessary but simple modifications and adjustments, to act as an "amplifier"and as a cable-infeed power arrangement.

Another technical problem is one of providing with the aid of simple means"amplifier"conditions which enable the flow of

liquid through an upstream duct section to be deflected via a first device to a pump or like means adapted to pass said flow of liquid to a downstream duct section via a second de- vice, said cable being adapted to pass through said two de- vices, or vice versa.

Another technical'problem resides in realising the signifi- cance of permitting each the first and the second device to include at least two mutually coacting parts and including packing material with which the outer surface of the cable and at least one of said mutually coacting parts can be brought into abutment.

In this layer application, another technical problem is one of realising the significance of using low-friction packing material, such as fluoroethylene plastic or corresponding ma- terial.

In order to enable the arrangement to be applied at a chosen position along a duct section through which a cable has al- ready been drawn, a technical problem resides in realising the significance of using packing material that consists of yarn, cord or ribbon wound one or more turns around the cable on the one hand, and dividing each of said first and second mutually coacting devices into a plurality of sections on the other hand, such as into two sections.

Another technical problem is one of realising the signifi- cance of and the advantages afforded by providing one of said parts with a circular groove or channel into which a circu- lar, annular portion of the second of said parts can be in- serted.

Another technical problem is one of providing with the aid of simple means conditions which will enable a third device to move said mutually coacting devices towards each other and

therewith generate a. n axially related and adapted pressure on the packing material, or to enable said parts to be moved away from each other when said parts shall be removed or when the pressure on the packing shall be reduced.

Another technical problem resides in realising the signifi- cance of permitting one of said parts to include an opening through which liquid or a duct section can exit and to con- struct said other part as a nozzle through which liquid can be injected into a duct section.

Another technical problem is one of realising the signifi- cance of and the advantages afforded by connecting a pump or the like to said first device, through the medium of a suc- tion line, and to said second device by means of a pressure line (via a control unit).

Another technical problem is one of realising the signifi- cance of permitting each of said first device and said second device to comprise a supplementary part with cable packing material placed between said mutually coacting parts.

SOLUTION The present invention takes as its starting point an arrange- ment _ the kind defined in the introduction, with the inten- tion c solving one or more of the aforesaid technical prob- lems.

The arrangement is particularly characterised in that at least-he nozzle, included in a first device, shall consist of at least two mutually coacting parts; and in that packing material can be brought into abutment with the outer surface of the cable and with at least one of said parts.

By wav of preferred embodiments lying within the scope of the inventive concept it is proposed that the packing arrangement used shall include a packing material that has low degree of friction against the outer surface of the cable.

It is also proposed that packing material in the form of yarn, cord or ribbon is wound once or more times around the cable.

According to one embodiment, the two mutually coacting parts are, in turn, divided into a plurality of parts or sections, for instance two sections.

It is also proposed in accordance with the invention that one of said parts might include a circular groove or channel into which a circular, annular portion of the other part can be inserted.

It is also proposed that the packing material can be inserted between the parts and enclosed by the annular portion.

According to the invention, means are provided for moving and pressing said parts closer together and therewith generate an axially related pressure on the packing material.

According to one embodiment, one of said parts might also function as a liquid injecting nozzle.

The scope of the invention also includes the use of specially desianed nozzles adapted to the cross-sectional area of a chosen cable, and that one and the same arranaement can be used for cables with different cross-sectional areas with the aid cf one and the same arrangement.

In order to solve one or more of the aforesaid technical problems, the present invention further takes its starting

point from an arrangement of the kind defined in the intro- duction.

More specifically, in respect of an arrangement of the afore- defined kind, the present invention provides means whereby a liquid flow passing through a duct section is coupled to a pump or like means via a first device, said pump or like means being adapted to deliver at least said liquid flow to a downstream duct section through the medium of a second de- vice.

In this embodiment, the present invention proposes that the first and the second device shall each comprise at least two mutually coacting parts, with packing material that can be brought into abutment with the cable and with at least one of said parts.

The invention also proposes that a packing arrangement shall consist of low-friction packing material, such as fluoroeth- ylene plastic, e. g.-Teflon-or corresponding material.

It is also proposed that the packing material shall consist of yarn, cord or ribbon that is wound once or more times around the cable.

At least one of the aforesaid first and second devices is di- vided into a number of parts or sections.

According to the invention, one of said parts should include a circular groove or channel into which a circular, annular portion of the second part can be inserted.

It is also proposed that the packing material can be inserted between the parts and enclosed by the annular portion.

In this regard, there is included a third device which func- tions to enable said parts to be moved towards and away from each other such as to adapt the pressure that acts axially on the packing.

According to one embodiment, one of said parts is comprised of an opening from which liquid can be taken from a duct sec- tion, while the second part is comprised of an opening through which liquid can be injected into a downstream duct section.

It is also proposed that a pump or like means shall be con- nected to the first device via a suction line and to the sec- ond device via a pressure line (via a control unit).

It is also proposed that the first device and the second de- vice shall consist of mutually corresponding parts with a ca- ble packing placed between mutually coacting portions.

ADVANTAGES Those advantages that can be considered primarily character- istic of an inventive packing arrangement reside in the pro- vision of conditions which enable a nozzle to be constructed in a first device for the infeed of one or more cables, where respective cable sections are able to pass through the first device whilst effectively sealed against the penetration of liquid although with small friction, and where the parts or components of the first device have been constructed to en- able said parts to be applied with associated packing mate- rial disposed around a cable section.

Those advantages that are primarily characteristic of an in- ventive arrangement reside in the ability of applying a cable drawing arrangement at a position along a duct section, and that the arrangement components are also constructed tc en-

able them to be placed around a cable that has already been drawn through said duct section.

The primary characteristic features of a packing arrangement according to the present invention are set forth in the char- acterising clause of the following Claim 1, the primary char- acteristic features of a first device and thereto belonging parts are set forth in the characterising clause of the fol- lowing Claim 13, and the primary characteristic features of an amplifier are set forth in the characterising clause of the following Claim 25.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of a packing arrangement and an amplifying ar- rangement constructed in accordance with the invention and at present preferred will now be described in more detail with reference to the accompanying drawings, in which Figure 1 illustrates schematically an arrangement for passing one or more cables through a cable-en- closing duct that forms a duct run, with the aid of pressurised liquid, such as water, with the means and devices significant to the invention being shown in block form; Figure 2 is a sectional view of a first device that in- cludes a nozzle for introducing cable sections into the duct run and provided with an opening for the controlled delivery of water;

Figure 3 is an enlarged view of the arrangement or the first device shown in Figure 2; Figure 4 is a principle illustration of an amplifying ar- rangement which is included in a second device and which can be applied over a cable section that has already been drawn through said duct section; Figure 5 is a side view and sectional view of said second device; Figure 6 is an enlarged view of part of the amplifying ar- rangement or said second device according to Fig- ure 5; Figure 7 is a sectional view of a sleeve arrangement ac- cording to a first embodiment, said sleeve ar- rangement being adapted to accommodate a cable with a smaller cross-sectional area than the ca- ble shown in Figure 3; Figure 8 is a sectional view of a sleeve arrangement ac- cording to a second embodiment adapted to accom- modate a cable with a larger cross-sectional area; and Figure 9 illustrates the sleeve arrangement according to Figure 8 adapted to accommodate a cable with a very small cross-sectional area.

DESCRIPTION OF EMBODIMENTS AT PRESENT PREFERRED Figure-thus illustrates an arrangement 1 for passing one or more cables 2 through a cable-enclosing duct with the aid of pressurised liquid 4, said duct being divided into duct sec-

tions such as to form a duct run 3 and said liquid passing through a valve 5 and through an opening in a first device 7, the nature of which will be described in more detail below with reference to Figures 2 and 3.

The arrangement also includes a cable-section infeed device 8 which functions to feed the cable 2 through a nozzle 6 in the first device 7 and into the upstream end-part 3b of the duct run 3 in response to mechanically applied pressure.

The arrangement also includes a control unit 9 which is adapted to cause the valve 5 to increase or decrease the pressure and the flow of water 4 through its opening, in re- sponse to the liquid flow through the duct run 3 among other things.

The flow of water through the duct is normally controlled manually by an operator, who observes and adjusts the flow through the duct run 3.

The illustrated arrangement 1 in Figure 1 also includes a second device 10 in the form of an arrangement for amplifying water pressure and/or water flow 4a. This device, or arrange- ment, has the form of a pump which includes a first liquid deviating means 31, a pump 32 for pumping liquid 4a, 4a', and a second liquid deviating means 33. The arrangement 10 will be described in more detail below with reference to Figures 4,5 and 6.

Although the cable end 2b is shown in Figure 1 to coact with a piston means 11 that has a seal lla against the inner sur- face 3a'of the duct section 3', it will be understood that such piston means 11 is not required in realising the func- tion of the present invention. However, practical trials and experiences have shown that such a piston means will often assist beneficially the work of drawing a cable through an

increased cable length drawn through the duct sections that make up the duct run 3.

A more detailed description of the principle functions of the arrangement 1 will be found in the aforementioned European patent publication.

The inventive arrangement illustrated in Figure 1 thus func- tions to enable one or more cables, in the illustrated case a single cable, through a duct run 3 with the aid of pressur- ised liquid 4, such as pressurised water.

The relative density of the cable 2 is chosen to correspond to or at least essentially to the relative density of the liquid used, where liquid 4a pressurised by a pump means (not shown) is allowed to flow through said duct run 3 and/or said duct section 3'whilst the cable sections are allowed to pass successively through a nozzle 6 and into the upstream end- part 3b of the duct 3.

When the velocity at which the liquid 4a passes through the duct run 3 is higher than the current velocity of the cable 2 through the duct sections 3, (3'), the cable 2 will be acted upon by a pulling force which acts along the duct-enclosed cable section 2, (2'), whilst said duct-enclosed cable sec- tion 2, (2') is supported by the liquid 4a (4a'), and/or its weight lightened thereby.

As before mentioned, the cable end 2b inserted into the duct may conveniently coact with a piston means 11. This piston means includes one or more elastic components whose periph- eral edge part can face towards and/or lie against the inner surface 3a'of the duct section 3', at least with an adapted standard liquid pressure, and permit the pressurised liquid 4a'to pass by the piston means 11 so as to create said liq- uid flow through the duct, the upstream located surface lla

of which can be influenced by said pressurised liquid and ex- erts a pulling force on the cable end 2b.

As will be seen from the side view and sectioned view of Fig- ures 2 and 3, the first device 7 includes a cable receiving <BR> <BR> <BR> nozzle 6 and an opening or inlet 50 for the liquid 4. It will also be seen that the first device 7 includes a so-called packing box or packing arrangement 7 that includes two mutu- ally coacting parts 71,72 which enclose packing material 73 that can be brought into abutment with the outer surface 2a of the cable 2 and at least against one of said parts.

The part 71 is referred to as the cable related part and the part 72 is referred to as the liquid infeed related part, this latter part being adapted for sealing coaction with an upstream located end-part 3b of the duct section 3.

The downstream located end-part 3a of the duct section 3 coacts with said second device 10.

The packing arrangement 70 is constructed according to the principes wherein when pressure is exerted axially on the sealing material, the packing material will be expanded radi- ally inro sealing abutment with the outer surface of the ca- ble.

The packing arrangement is exemplified hereinafter as a so- called box packing in which the packing material 73 is a low- friction type of material.

Fluoroehylene plastic, either in yarn form, preferably braided yarn, has been found particularly suitable as a pack- ing material in practical trials.

One such suitable material is retailed under the designation "Teflon". Other low-friction packing materials 73 may, of course, be used.

In the case of the illustrated embodiment, the packing mate- rial 73 has the form of yarn or ribbon wound one or more turns around the periphery of the cable 2 or around its outer surface 2a, said yarn or ribbon being wound in two turns in the illustrated case.

Each of the two mutually coacting parts 71,72 of the packing arrangement 70 is divided into several sections.

Most preferably, said parts 71 and 72 are divided into two sections with a parting line-P-orientated diametrically relative to the duct section 3 and orientated centrally in relation to the cable 2.

The section plane-P-shown in Figure 2 may conveniently be a plane which extends perpendicularly to the illustrated sec- tion plane of the two parts 71,72.

Although the drawing shows the diameter-related parting plane -P-shows the part 71 divided into two identical sections, it lies within the scope of the invention to divide the part 71 (and also the part 72) in radius-related planes with an angle greater than 180°, and for one section to be just smaller than 90° and to place the smaller section over the larger section.

The one part 71 and its coacting sections may conveniently include a circular groove 71a against which a circular or an- nular portion 72a of the second part 72 can be guidably in- serted.

The part 71 also includes a semi-cylindrical part 71b.

This semi-cylindrical part 71b includes an inner hole or channel 71e, the cross-section of which only slightly exceeds the cross-sectional area of the cable 2 in the embodiment shown in Figures 2 and 3.

When working with a thinner cable 2, it is suggested that the channel 71e is provided with a sleeve 71f whose hole or chan- nel has a cross-sectional area which only slightly exceeds the cross-sectional area of this thinner cable and that the outer cylindrical surface of the sleeve bears against the in- ner cylindrical surface of the channel 71e. An arrangement that includes such sleeves will be described hereinafter with reference to Figures 7-9.

The outer surface 71b'of the semi-cylindrical part 71b is adapted for sealing coaction with a duct section 3"or a like coupling means.

The part 71 also includes an inner, sleeve-like part 71c which extends past an edge surface 72a'of a sleeve-like outer part 72a and forms the groove 71a, the edge region or edge surface 71c'of which is adapted to form a support or a counterpressure surface for the packing material 73.

The packing material 73 is inserted between the parts 71 and 72 and is enclosed thereby between the sleeve-like part 71c and the annular portion 72a.

The arrangement includes a third device 74 for moving the part 71,72 towards and away from each other so as to there- with create an adapted pressure which acts axially on the packing material 73.

The pressure acting axially on the packing material 73 is in- creased by moving the parts 71 and 72 closer together in a

controlled manner, therewith obtaining tighter coaction be- tween the outer surface 2a and the packing material 73 in a radial sense, with a slightly higher friction, and vice versa.

This device 74 may have the form of a bottlescrew arrange- ment. Alternatively, the part 71c may be provided with an ex- ternal thread and the part 72a provided with an inner thread, in which case the relative displacement of the parts 71 and 72 is effected by turning the part 71 relative to the part 72.

Figure 4 illustrates the use of a second device 10 in the form of a pressure or flow amplifying arrangement, which can be applied conveniently should the cable 2 stick in a duct section 3', preferably with the aid of a piston arrangement 11.

In such an event, the amplifying arrangement 10 shall be ap- plied upstream of the cable end 2b.

This can be effected on the one hand by severing the duct section 3,3'upstream of the cable end 2b and displacing the resultant duct ends 3c and 3d through an adapted distance therebetween, said distance being adapted to accommodate the various parts of the amplifying arrangement 10.

On the other hand, the duct sections 3,3'may conveniently be separated from one another through the medium of a stan- dard join therebetween.

It will be noted that the various parts of the amplifying ar- rangement 10 are generally identical to the parts 71 and 72 in Figure 2, although with the addition of the part 71.

As illustrated in Figure 4, a liquid flow 4a passing through a duct section 3 shall be deflected fully to a pump 32 via a first liquid deviating device 31, said pump being adapted to deliver said liquid flow 4a', via a second liquid deviating device 33, to a downstream located duct section 3', wherein said cable 2 is adapted to pass directly through said devices 31,33.

The first and the second liquid deviating devices 31,33 are comprised of at least two mutually coacting parts 41,42 with packing material 43 lying against the cable 2 and against at least one of the parts 41,42.

The packing arrangement 40 and packing material 43 are also constructed in accordance with the principles of a box pack- ing, with the packing material being of a low-friction type wherewith the use of a fluoroethylene plastic, such as "Teflon", or some like material is recommended.

Similar to the packing material 73, the packing material 43 consists of one or more turns of yarn or ribbon around the cable 2, two turns in the illustrated case.

Each of the first and second parts 41,42 is divided into a number of parts or sections, with a dividing plane-P-orien- tated diametrically and through a centre line on the cable 2, in the same way as that earlier described.

One part 41 may include a circular groove 41a in which a cir- cular, annular portion 42a of the second part 42 can be in- serted.

The packing material 43 is disposed between the parts 41 and 42 and enclosed by the annular portion 41a.

The arrangement 10 also includes a third device (74) which functions to enable the parts 41,42 to be moved towards one another and therewith increase the pressure axially on the packing material 43, said third device not being shown in Figure 5.

The alternative devices illustrated in Figures 2 and 3 can also be used in this latter case.

In the illustrated case, the part 41 is adapted to function as a nozzle 51 or opening through which liquid 4a is fed out from the duct section 3, said nozzle or opening being coupled to a suction hose 32a and to the pump 32 from which the liq- uid is pumped via a pressure hose 32b (preferably to and via a control unit 9') through a hose 35 to said device 33, while the other part 42 functions as a nozzle 52 or opening through which liquid is injected into the duct section 3'. An opera- tor, instead of including a control unit 9'may visually monitor the system.

Although not shown for reasons of clarity, the amplifying ar- rangement 10 may include an accumulator tank that can be cou- pled to the suction hose 32a when necessary.

Figures 5 and 6 show that the first part 41 and the second part 42 each comprise a complementary part having packing ma- terial 43 for the cable 2 placed between the mutually coacting parts.

Control units 9 (and 9'respectively) may principally be of the same kind and may, inter alia, be adapted to control the liquid flow and liquid pressure in the duct section 3 (3').

The control unit may also be adapted to control cable inser- tion means 8 and also other functions associated with the de- scribed system.

Figure 7 is a sectional view of a first embodiment of a sleeve arrangement adapted to accommodate a slightly thinner cable than that shown in Figure 3. It will be noted that in this case the sleeve 71f has a collar 71g, which lies against a surface 71g'.

The sleeve 71f is divided into two parts and has a tubular section 71h whose outer surface 71h'lies against the surface 71k.

The bore of the sleeve 71f has a cross-sectional area that slightly exceeds the cross-sectional area of the cable 2'.

Figure 8 is a sectional view of a second embodiment of a sleeve arrangement, said arrangement including a first two- part support sleeve 81 belonging to the part 71, and a second two-part support sleeve 82 belonging to the part 72.

Both sleeves 81 and 82 have inner bores whose cross-sectional areas are adapted to the cross-sectional area of the cable 2.

In this case, the packing material 73 is clamped firmly be- tween the support sleeves 81 and 82.

Figure 9 is intended to illustrate that the inner bores of the support sleeves 81,82 are adapted to the cross-sectional area of a smaller gauge cable 2'.

Preferably, the sleeves will be fastened to said parts (screwed or fastened in some equivalent manner) so that they will not be displaced axially by the liquid pressure acting on one edge of the sleeve.

Although the embodiment including the"amplifier"illustrates the use of two liquid deviating devices 31 and 33 and shows the cable 2 moving straight through said devices 31,33, al-

ternative devices can be used within the scope of the inven- tive concept. Thus, it lies within the scope of the invention to use other embodiments in which the cable sections are de- flected to form a loop, with the pump unit used being coupled directly between opposing duct sections 3c, 3d.

It should be noticed that the chosen expression"low fric- tion"for the displacement or movement of the cable section through the packing arrangement 70 is meant as if the parts 71 and 72 are thus displaced in relation to each other so that the packing material 73, compressed between these parts, firstly barely abuts to the outer surface of the cable sec- tion, in which adjustment position it can be accepted that a certain amount of water is allowed to leak between the mate- rial 73 and the outer surface.

Secondly, this expression can also mean that the parts 71 and 72 are thus displaced in relation to each other so that the packing material 73, compressed between these parts, seal- ingly abuts to the outer surface of the cable section, in which adjustment position no water is allowed to leak between the material 73 and the outer surface.

It is in other words a matter of adaptation of the parts 71 and 72 so that an adjustment position adapted for waterproof- ing does not give an unnecessarily high friction between the packing material and the outer surface of the cable section.

It is also within the scope of the present invention that the cable section may be lead out of the duct run 3, at the means 31 through a not shown angular deflection and a packing ar- rangement, into a loop and thereafter into the means 33, through a not shown angular deflection and a packing arrange- ment, of a kind previously described.

It will be understood that the invention is not restricted to the aforedescribed and illustrated exemplifying embodiments thereof and that modifications can be made within the scope of the inventive concept as defined in the following Claims.