Device for laying a cable in a conduit with lubricating capacity

Abstract

Device for installing an elongated element (100) in a conduit (200), comprising a pressure housing (10) having: - an inlet port (12), - an outlet port (11) arranged to connect to the conduit (200) to introduce the elongated element (100) into the conduit (200) with an actuating fluid, - an actuating fluid chamber (20), arranged to receive the pressurized actuating fluid and distribute it in the conduit (200) with the elongated element (100), - a lubricant chamber (30), arranged to receive a lubricant and distribute it over an outer surface of the elongated element (100), the lubricant chamber (30) being located upstream of the actuating fluid chamber (20), characterized in that the pressure housing (10) comprises an upstream chamber (40), arranged to receive the pressurized actuating fluid and located upstream of the lubricant chamber (30).

Description

Device for laying a cable in a conduit with lubricating capacity The present invention relates to the field of specialized machines for inserting cables into conduits, and the invention relates, in particular, to the field of machines, apparatus and devices used at the entrance of a conduit to assist and drive the insertion of cables into the conduit. In the prior art, it is known to use a propellant fluid (gas or liquid) introduced into the conduit inlet along with the cable to improve cable transport within the conduit and increase the length of cable that can be installed. The prior art also includes the use of lubrication to improve cable insertion, as described in US patent 7,992,685 B2. However, the described system can experience lubricant leakage and is complex, requiring the installation of several units before the cable can be laid in the conduit. US patent 7,992,685 B2 describes a lubrication apparatus for installing fiber optic communication cables and copper cables in conduits and protective ducts. Document FR2,655,783 A1 describes an injection gun, specifically designed for pulling cables into a long conduit, with lubricant deposition capabilities. The present invention aims to address the aforementioned drawbacks of the prior art and proposes, firstly, a device for inserting an elongated element into a conduit, enabling ease of use with reliable operation and mitigating the risk of lubricant leakage. The invention is defined in claim 1. With this objective, a first aspect of the invention relates to a device for installing an elongated element in a conduit, comprising a pressure housing having: - an inlet opening to receive the elongated element, - an outlet opening arranged to connect to the conduit for introducing the elongated element into the conduit with a driving fluid, - a driving fluid chamber, arranged to receive the driving fluid supplied under pressure and to distribute the driving fluid in the conduit with the elongated element, - a lubricant chamber, arranged to receive a lubricant and to distribute the lubricant over an outer surface of the elongated element, the lubricant chamber being located upstream (according to the displacement of the elongated element) of the driving fluid chamber, characterized in that the pressure housing comprises an upstream chamber, arranged to receive the pressurized driving fluid and located upstream of the lubricant chamber (according to the displacement of the elongated element), where the upstream chamber is a dead space for the received pressurized driving fluid. The pressure housing of the device according to the above embodiment comprises three distinct chambers. From the inlet opening to the outlet opening (following the direction of travel of the elongated element), the order is as follows: the upstream chamber, the lubricant chamber, and the driving fluid chamber. In other words, the lubricant chamber is located between the upstream chamber and the driving fluid chamber, so that any lubricant leakage, even if in the upstream direction, will be contained within the pressure housing and will mix with the driving fluid (present in both the upstream and driving fluid chambers). Therefore, the lubricant cannot leak out of the pressure housing. Furthermore, the three chambers are provided and formed by the pressure housing itself, thus reducing the preparation work required to install the device and begin the laying operation. According to one embodiment, the pressure housing may comprise a fluid opening for receiving the pressurized driving fluid, and the fluid opening may be arranged to supply the pressure housing with pressurized driving fluid downstream of the lubricant chamber. In other words, the pressurized driving fluid is supplied to the pressure chamber at a location downstream of the lubricant chamber (downstream with reference to the direction of travel of the elongated element). Therefore, the driving fluid can flow directly into the conduit without passing through or around the lubricant chamber: the pressure housing remains compact and / or free of bypass or through-channels for conveying the driving fluid from a point upstream of the lubricant chamber to a point downstream of the lubricant chamber. According to one embodiment, the fluid opening can be arranged to supply the driving fluid chamber with pressurized driving fluid and, preferably, the fluid opening can be arranged to supply the pressurized driving fluid directly into the driving fluid chamber. The structure of the pressure housing remains simple: the pressurized driving fluid is supplied directly into the driving fluid chamber, and from there, the pressurized driving fluid can flow into the conduit (with the elongated element) without passing through the lubricant chamber. According to the invention, the upstream chamber is a dead space for the received pressurized driving fluid. According to one embodiment, the upstream chamber may be free of a driving fluid outlet and / or the upstream chamber may comprise a single fluid communication conduit for receiving the pressurized driving fluid. In other words, there is no (or negligible) flow of driving fluid into or through the upstream chamber. The driving fluid in the upstream chamber can be defined as a static buffer to prevent any direct leakage of lubricant from the pressure housing. If the pressurized driving fluid supplied to the interior of the pressure housing and flowing into the conduit has a predetermined flow rate, then more than 90%, preferably more than 95%, and more preferably more than 99% of said predetermined flow rate flows from the fluid opening directly into the conduit.This means that a very small portion of the flow (less than 10%, preferably less than 5%, and preferably less than 1%) flows into the upstream chamber. It should be noted that during the startup phase, when the pressure housing is still free of driving fluid, there is a preliminary phase where the pressure housing (both the driving fluid chamber and the upstream chamber) must be filled with the driving fluid. During this preliminary phase, the driving fluid must flow into the upstream chamber. However, after this preliminary phase, there is little to no flow of pressurized driving fluid in the direction of the upstream chamber. Consequently, under the established conditions for running the elongated element, there is no flow of driving fluid from the upstream chamber to the driving fluid chamber, nor through or around the lubricant chamber.The pressure housing remains compact. According to one embodiment, the device may comprise a foam piece disposed between the driving fluid chamber and the lubricant chamber. This foam piece forms a wall of the lubricant chamber and is in contact with the lubricant. This allows for uniform, smooth, and reliable rubbing and deposition of the lubricant around the elongated element, with effective separation to prevent massive leakage of lubricant into the driving fluid chamber. According to one embodiment, the device may comprise a support that receives and holds the foam piece in a working position where the foam piece is in contact with the elongated element, the support being arranged between the foam piece and the pressure housing. Such a support, an intermediate part between the pressure housing and the foam piece, allows for easy replacement, easy repair, and modularity. When the pressure housing is manufactured from upper and lower parts (or two halves), the upper part can be sealed onto the lower part in this manner without the foam material being in between, which would hinder a fluid-tight seal. According to one embodiment, the support can be a ring, preferably a closed ring. According to one embodiment, the pressure housing may comprise a groove or recess to hold the support in a predefined position along an axial direction of the elongated element. As an example, the foam piece can have a thickness of 15 mm–45 mm, for example, 25 mm for a cable with a diameter of 80 mm. The foam piece can be made of a polyester or polyether filter foam material. According to one embodiment, the device may include a second foam piece positioned between the upstream chamber and the lubricant chamber. This second foam piece forms a wall of the lubricant chamber and is in contact with the lubricant. This provides effective separation to prevent massive leakage of lubricant into the upstream chamber. According to one embodiment, the device may comprise a second support that receives and holds the second foam piece in a working position where the second foam piece is in contact with the elongated element, the second support being arranged between the second foam piece and the pressure housing. This second support, an intermediate part between the pressure housing and the second foam piece, allows for easy replacement, easy repair, and modularity. When the pressure housing is made of upper and lower parts (or two halves), the upper part can be closed over the lower part in this way without the foam material being in between, which would hinder a fluid-tight seal. According to one embodiment, the second support can be a ring, preferably a closed ring. According to one embodiment, the pressure housing may comprise a groove or recess to hold the second support in a predefined position along an axial direction of the elongated element. As an example, the second piece of foam can have a thickness of 15 mm to 45 mm, for example, 25 mm for a cable of Ø80 mm. According to one embodiment, the second piece of foam can be made of a polyester or polyether filter foam material. According to one embodiment, the second support and the support can have the same external dimensions so that they are interchangeable. According to one embodiment, the device may comprise a lubricant conduit disposed between the lubricant chamber and the driving fluid chamber. This lubricant conduit ensures that excess lubricant pressure is not mixed into the driving fluid. According to one embodiment, the lubricant conduit can be mounted on top of the pressure housing, preferably higher than the top of the cable in a vertical direction. According to this embodiment, when the lubricant is denser than the driving fluid, it naturally surrounds the cable as it enters the driving fluid chamber. According to one embodiment, the lubricant conduit can be arranged on the support. According to one embodiment, the lubricant conduit may be a tube or pipe at least partially external to the pressure housing. The lubricant conduit may be arranged to supply lubricant to the interior of the driving fluid chamber. Installing a lubricant conduit separate from the support and / or the pressure housing allows for a compact design in the axial direction (the axial direction of the elongated element). According to one embodiment, the device may comprise a driving fluid conduit disposed between the upstream chamber and the driving fluid chamber. The driving fluid conduit provides fluid communication between the upstream chamber and the driving fluid chamber. According to one embodiment, the driving fluid conduit may be a tube or pipe at least partially external to the pressure housing. Installing a driving fluid conduit separate from the pressure housing allows for a compact design in the axial direction (the axial direction of the elongated element). Preferably, the driving fluid conduit may be located in a lower portion of the pressure housing (in the vertical direction) so that no air void can accumulate in the driving fluid conduit and impede operation. According to one embodiment, the inlet opening may comprise at least one lip seal and a guide block. According to another embodiment, the device may include an external lubrication unit located upstream of the pressure housing. According to one embodiment, the device may comprise driving means such as driving tracks or driving rollers, arranged to push the elongated element into the inlet opening. According to one embodiment, the pressure housing may comprise two halves joined together to surround the elongated element. The specific embodiment provides an easy-to-install device. According to one embodiment, the device may comprise a sealing element disposed between the pressure housing and the conduit. Preferably, the sealing element between the pressure housing and the conduit, the lip seal (cable) of the inlet opening, and the supports with foam piece are all non-divisible and are threaded over the cable before being mounted in the pressure housing and conduit. According to one embodiment, the driving fluid chamber can be arranged to surround the elongated element at least partially and, preferably, can be arranged to completely surround the elongated element in a direction tangential to the elongated element. According to one embodiment, the lubricant chamber can be arranged to surround the elongated element at least partially and, preferably, can be arranged to completely surround the elongated element in a direction tangential to the elongated element. According to one embodiment, the upstream camera can be arranged to surround the elongated element at least partially and, preferably, can be arranged to completely surround the elongated element in a direction tangential to the elongated element. According to the invention, the upstream chamber defines a dead volume to receive the driving fluid. In other words, the upstream chamber is a space where there is no driving fluid flow. The upstream chamber provides a pressurized space to minimize or suppress lubricant leakage from the lubricant chamber and to capture any lubricant that leaks from the lubricant chamber, if necessary. According to one embodiment, the driving fluid provided in the upstream chamber can be static, except to compensate for leakage to the outside of the pressure housing and / or into the lubricant chamber. According to one embodiment, the driving fluid chamber may have a downstream or end section defined by, or comprising, the outlet opening. According to one embodiment, the upstream chamber may have a starting or upstream section defined by, or comprising, the inlet opening. A second aspect of the invention relates to an apparatus for installing an elongated element in a conduit, comprising: - the device for installing an elongated element in a duct according to the first aspect, - a propellant fluid supply unit, connected to the device for installing an elongated element in a conduit and arranged to deliver the propellant fluid under pressure to the propellant fluid chamber, - a lubricant supply unit, connected to the device to install an elongated element inside a conduit and arranged to deliver the lubricant under pressure to the lubricant chamber. According to one realization: - The driving fluid supply unit is arranged to supply the driving fluid at a first pressure, - The lubricant supply unit is arranged to deliver the lubricant at the first pressure ± 10%, and preferably at a pressure higher than the first pressure by a maximum of 1 bar, preferably at a pressure higher than the first pressure by a maximum of 0.5 bar, and more preferably at a pressure higher than the first pressure by a maximum of 0.2 bar. According to one embodiment, the driving fluid can be air. The driving fluid can be a liquid, preferably 90% water. The lubricant can be oil-based or water-based with polymers, e.g., optionally with silicone additives. Alternatively, bentonite could be used to disperse in the driving fluid. Another aspect not covered by the claims relates to a method of installing an elongated element in a duct with the device of the first aspect, comprising the steps of: - Assemble the foam piece and the second foam piece onto the support and the second support respectively, - Install the lip seal onto the elongated element, - Install the foam piece - support assembly over the elongated element, - Install the second piece of foam - second support assembly over the elongated element, - Install the sealing element over the duct, - optionally attach a piston to the elongated element, - Insert the elongated element with the optional plunger into the conduit for a short distance, such as at least 10 cm, - Place the lip seal, guide block, support, second support, and conduit in the first half of the pressure housing, and install the sealing element between the first half of the pressure housing and the conduit, - couple the second half of the pressure housing to the first half of the pressure housing to surround the lip seal, guide block, support, second support, sealing element, a portion of the conduit and a portion of the elongated element, to form the driving fluid chamber, lubricant chamber and upstream chamber. In this description, an elongated element may refer to a cable, wire, fiber, optical fiber, transport tube, bundle, or a combination thereof. Typically, these elongated elements are encased in a protective sheath (made of insulating material, such as plastic), but they may also be bare. These elongated elements may have a diameter of one (or less) or several millimeters, or several centimeters, and a length of several meters, several hundred meters, or several kilometers. In this description, a conduit can also refer to a pipe, tube, or any hollow passage through which the elongated element must be laid. These conduits may be buried and can be several meters, several hundred meters, or several kilometers long. In this description, the upstream and downstream directions should be considered with respect to the direction of displacement of the elongated element. For example, when considering the pressure housing, the inlet opening for the elongated element and the outlet opening for the elongated element provided in the pressure housing are, respectively, an upstream (inlet) opening and a downstream (outlet) opening. Other features and advantages of the present invention will become clearer from the following detailed description of particular non-limiting examples of the invention, illustrated by the accompanying drawings, where Figure 1 represents a schematic view of a device for installing an elongated element. Figure 1 shows a simplified general view of a device according to the invention. An elongated element 100, equipped at its front end with a sealing cap 110, is driven through a pressure housing 10 by driving means 80, to be laid or installed in a conduit 200. In detail, the present case shows an installation that uses a liquid to assist the insertion and displacement of the elongated element 100 in the conduit 200. This method is generally called flotation. A pull plunger could be used, in which case the method is called water push-pull. Such a plunger can be attached to a forward end of the elongated element by, for example, a pull eye, cable nets, or a (divisible) clamp attached to the outer surface of the elongated element. However, the invention can be implemented by the assistance of gas (air) as the driving fluid, and the method is called injection or blowing. The pressure housing 10 comprises a fluid opening 15 for receiving pressurized driving fluid from a driving fluid supply unit. The overall structure of the equipment comprises the pressure housing 10, which is connected to the conduit 200 and receives the elongated element 100 for insertion into the conduit 200 along with pressurized driving fluid. The movement of the elongated element 100 is initially caused by a thrust force generated by the driving means 80. After initial installation, the movement is caused by the combined action of the thrust force generated by the driving means 80 and the drag (propulsive) forces created by the driving fluid along the elongated element 100 when no piston is used, as in this case (buoyancy). The buoyancy effect provided by the driving fluid reduces the effective weight of the cable, resulting in reduced friction and a longer installation length.When using a plunger (no image), a local pulling force at the front end of the cable also contributes to the installation. The drive means 80 may comprise a track driven by an electric motor and opposing rollers (here, four rollers) to support the elongated element 100 and ensure low or zero slippage during propulsion. However, other types of drive means may be used (with two tracks, with rollers only, etc.). Typically (not shown), the elongated element 100 is stored on a reel located upstream of the drive means. The pressure housing 10 supports a guide block 63 and a lip seal that define, for the elongated element 100, an inlet opening 12 into the pressure housing 10. The pressure housing 10 is coupled to the conduit 200 by means of retaining rings 61 and 62, which define an outlet opening 11 for the elongated element 100 outside the pressure housing. To prevent leakage of the driving fluid, the retaining ring 61 (preferably divisible) holds a sealing element (e.g., a gasket, an O-ring, a packing, etc.) that comes into contact with the outer surface of the conduit 200. The installation of the elongated element 100 in the duct 200 could be facilitated by using lubricant to reduce friction of the elongated element 100 in the duct 200. To this end, the pressure housing 10 is designed to define three distinct chambers, located in the pressure housing 10, between the inlet opening 12 of the elongated element 100 and the outlet opening 11 of the elongated element 100. The pressure housing 10 comprises a foam piece 51 with a support 53 and a second foam piece 52 with a second support 54. The foam piece 51 and the second foam piece 52 can be rings made of polyester or polyether filter foam material and surround the elongated element 100. The foam piece 51 and the second foam piece 52 are held and positioned in the pressure housing 10 by the support 53 and the second support 54, respectively, to divide the interior space of the pressure housing 10 into: - an upstream chamber 40, located between the inlet opening 12 and the second foam piece 52, - a lubricant chamber 30, located between the second foam piece 52 and the foam piece 51, - a propellant fluid chamber 20 located between the foam piece 51 and the outlet opening 11. It should be noted that the elongated element 100 passes through the pressure housing portions 10 in the following sequence: i- the inlet opening 12 (guide block 63 and lip seal) ii- the upstream chamber 40, iii- the lubricant chamber 30, iv- the propellant fluid chamber 20, v- the outlet opening 1 (retaining rings 61, 63). The pressure housing 10 comprises a lubricant opening 16 for feeding and filling the lubricant chamber 30 with pressurized lubricant. The device comprises a lubricant conduit 14 which, in the present embodiment, may be a (partially external) tube to provide fluid communication between the lubricant chamber 30 and the driving fluid chamber 20. As can be seen in Figure 1, the fluid opening 15 communicates directly with the propellant fluid chamber 20 to supply it with pressurized propellant fluid. In particular, it can be observed that the pressurized propellant fluid, once in the propellant fluid chamber 20, can flow directly through the outlet opening 1 and into the conduit 200. The device also comprises a driving fluid conduit 13, which, in the present embodiment, may be a (partially external) tube to provide fluid communication between the driving fluid chamber 20 and the upstream chamber 40. As can be seen in Figure 1, the driving fluid conduit 13 has the primary purpose of filling the upstream chamber 40 during a preliminary phase prior to the established operation, during which the elongated element 100 is inserted into the conduit 200. In particular, after this preliminary phase, the upstream chamber 40 is filled with driving fluid, and there is no or almost no flow of driving fluid through the driving fluid conduit 13: the driving fluid supplied through the fluid opening 15 can only escape into the conduit 200. To improve the insertion of the elongated element 100 into the pressure housing 10, an external lubrication unit 70 may be optionally provided between the driving means 80 and the pressure housing 10. This external lubrication unit 70 may comprise an external foam piece 72 with a 360° internal groove around the elongated element 100, supported by an external bracket 71 and connected to an external lubricant reservoir 73 for gravity lubrication. To facilitate the preparation of the device, the pressure housing 10 could be provided in two separate parts, or halves, which fit together to clamp the guide block 63, the lip seal, the second support 54, the support 53, the clamping rings 61, 62... The guide block 63 and the clamping rings 61, 62 are preferably divisible. In practice, each half of the guide block 63 and the retaining rings 61 and 62 has a mating feature, and the pressure housing (also divisible) has a complementary mating feature. These mating features and complementary mating features can be grooves, pins, holes, or bolts. Therefore, when preparing the lower half of the pressure housing, the respective halves of the guide block 63 and the retaining rings 61 and 62 can be positioned correctly, and the same applies to the upper half of the pressure housing. To hold the components in place in the upper half of the pressure housing, the parts can be provided with a press fit, screws, or a light press-fit structure. When all the half-parts are mated to their respective half of the pressure housing, the halves of the pressure housing can be joined together.Of course, the non-divisible parts (foam pieces and supports, lip seals...) are pre-placed on the elongated element 100 and pre-positioned in the correct axial position with respect to one half of the pressure housing (preferably the lower part). In this example, the driving fluid can be a liquid, preferably water, either fresh or salt water. The lubricant can be oil-based or water-based. The elongated element can be a power cable with a diameter of 80 mm, sheathed in plastic. During operation, the elongated element 100 is pushed into the pressure housing 10 by the driving means 80. The external lubrication unit 70 deposits a thin layer of lubricant onto the elongated element 100, thereby facilitating its passage through the guide block 63 and the lip seal. Pressurized driving fluid is supplied to fluid opening 15 at a pressure ranging from 0 bar to 16, 20, or even 25 bar. The driving fluid fills driving fluid chamber 20, upstream chamber 40 (via driving fluid conduit 13), and flows into conduit 200 with the elongated element 100. Once upstream chamber 40 is completely filled with driving fluid, all the driving fluid flows directly from fluid opening 15 into conduit 200 (as shown by the arrows in Figure 1). Specifically, during normal operation, there is no driving fluid flow from upstream chamber 40 to driving fluid chamber 20 (except for a small reverse flow, primarily through conduit 13, to compensate for unexpected leakage through the lip seal and guide block 63). Therefore, there is no flow of driving fluid through or around lubricant chamber 30.This allows for the design and maintenance of a compact pressure housing 10. In fact, if the driving fluid were to pass through or around the lubricant chamber 30, it would be necessary to provide a passage arranged parallel to the lubricant chamber 30 and having approximately the same area as the passage space in the conduit 200 defined between the conduit 200 and the elongated element 100. This would detrimentally increase the size of the pressure housing 10. Simultaneously, pressurized lubricant is supplied to the lubricant chamber 30 through the lubricant opening 16 at a pressure equal to, or preferably slightly higher than, the pressure applied to the driving fluid. For example, if the driving fluid pressure is 8 bar, the lubricant pressure can be 8.5 bar, preferably 8.2 bar or 8.1 bar. Therefore, the lubricant fills the lubricant chamber 30, impregnates the foam part 51 and the second foam part 52, can adhere to the elongated element 100 to ensure the presence of a lubricant layer on the elongated element 100, and the excess lubricant exits the lubricant chamber 30 through the lubricant conduit 14 to mix with the driving fluid in the driving fluid chamber 20 and flow into the conduit 200, as shown in Figure 1. The present device provides precise dosing of lubricant in the driving fluid due to the specific structure (the lubricant chamber 30 distinct from the driving fluid chamber 20 and the upstream chamber 40, and the lubricant conduit 14 that feeds the driving fluid chamber 20). Furthermore, it should be noted that the lubricant can only leak from the lubricant chamber 30 into the drive fluid chamber 20 and / or into the upstream chamber 40. Therefore, lubricant leaks from the lubricant chamber 30 do not result in any external lubricant leakage: the device collects the leaked lubricant in the drive fluid. If the upstream chamber 40 leaks through the lip seal and guide block 63, it will be pressurized drive fluid (water) that leaks to the outside, with less serious consequences compared to an external lubricant leak. In fact, external lubricant leaks should be avoided for environmental reasons, and pressurized lubricant sprayed onto the drive media can cause sliding problems. Note that, along the vertical direction, the lubricant channel 14 is positioned above the pressure housing 10. If the lubricant is denser than the driving fluid, it could flow out of the reservoir at a level lower than necessary to completely surround the cable if the lubricant channel 14 were located at the bottom of the pressure housing, thus preventing this waste. Furthermore, the lubricant opening 16 is preferably positioned at the bottom so that the lubricant will always flow past (surround) the cable as it exits through the lubricant channel 14. Note that, in the vertical direction, the driving fluid conduit 13 is located below the pressure housing 10, to avoid any air bubbles or vacuums that could block the passage of the driving fluid. Of course, it is understood that improvements and / or modifications obvious to a person skilled in the art may be implemented, which are still within the scope of the invention as defined by the appended claims. In particular, the lubricant conduit 14, shown as an external tube separate from the pressure housing 10, may be provided as a slot or hole passing through the support 53 to provide fluid communication between the lubricant chamber 30 and the driving fluid chamber 20. Also, the driving fluid conduit 13, shown as external to and separate from the pressure housing 10, may be provided as an internal conduit within the pressure housing 10 between the upstream chamber 40 and the driving fluid chamber 20, or as a branch from the fluid opening 15, such as a Y-junction. In the previous example, the driving fluid is a liquid, preferably water, either fresh or salt water. The lubricant is oil- or water-based. The elongated element is a power cable with a diameter of approximately 80 mm, sheathed in plastic. However, the device shown in Figure 1 can be used for other applications with different fluids and with different sizes of the elongated element. Optionally (not shown), a reduced dosing flow rate of driving fluid (water) can be fed into the upstream chamber 40 through a small water opening (not shown), at a pressure slightly higher than the pressure in the driving fluid chamber 20, to continuously dilute the fluid in the upstream chamber 40 and prevent accumulation (saturation) of lubricant in the upstream chamber 40.

Claims

1. A device for installing an elongated element (100) in a conduit (200), comprising a pressure housing (10) having: - an inlet opening (12) for receiving the elongated element (100), - an outlet opening (11) arranged to connect to the conduit (200) for introducing the elongated element (100) into the conduit (200) with a driving fluid, - a driving fluid chamber (20) arranged to receive the driving fluid supplied under pressure and distribute the driving fluid in the conduit (200) with the elongated element (100), - a lubricant chamber (30) arranged to receive a lubricant and distribute the lubricant over an outer surface of the elongated element (100), the lubricant chamber (30) being located upstream of the driving fluid chamber (20), wherein the pressure housing (10) comprises an upstream chamber (40),arranged to receive the pressurized driving fluid and located upstream of the lubricant chamber (30), characterized in that the upstream chamber (40) is a dead space for the received pressurized driving fluid.

2. The device according to claim 1, wherein the pressure housing (10) comprises a fluid opening (15) for receiving said pressurized driving fluid and wherein the fluid opening (15) is arranged to supply the pressure housing (10) with pressurized driving fluid downstream of the lubricant chamber (30).

3. The device according to claim 1 or 2, wherein the fluid opening (15) is arranged to supply the driving fluid chamber (20) with pressurized driving fluid and, preferably, the fluid opening (15) is arranged to supply the driving fluid chamber (20) directly with pressurized driving fluid.

4. The device according to any one of claims 1 to 3,comprising a foam piece (51) disposed between the propellant fluid chamber (20) and the lubricant chamber (30).

5. The device according to claim 4, comprising a support (53) that receives and holds the foam piece (51) in a working position in which the foam piece (51) is in contact with the elongated element (100), the support (53) being disposed between the foam piece (51) and the pressure housing (10).

6. The device according to any one of claims 1 to 5, comprising a second foam piece (52) disposed between the upstream chamber (40) and the lubricant chamber (30).

7. The device according to claim 6, comprising a second support (54) that receives and holds the second foam piece (52) in a working position in which the second foam piece (52) is in contact with the elongated element (100).the second support (54) being disposed between the second foam piece (52) and the pressure housing (10), and wherein the second support (54) and the support (53) have the same external dimensions so as to be interchangeable.

8. The device according to any one of claims 1 to 7, comprising a lubricant conduit (14) disposed between the lubricant chamber (30) and the driving fluid chamber (20).

9. The device according to claim 8, wherein the lubricant conduit (14) is mounted on an upper portion of the pressure housing (10), preferably higher than the upper portion of the elongated element (100) in a vertical direction.

10. The device according to claim 8 or 9, insofar as it depends on any one of claims 7 to 8, wherein the lubricant conduit (14) is disposed on the support (53).

11. The device according to any one of claims 1 to 10,comprising a driving fluid conduit (13) disposed between the upstream chamber (40) and the driving fluid chamber (20).

12. The device according to any one of claims 1 to 11, wherein the inlet opening (12) comprises at least one lip seal and a guide block (63).

13. The device according to any one of claims 1 to 12, comprising an external lubrication unit (70) located upstream of the pressure housing (10).

14. Apparatus for installing an elongated element (100) in a conduit (200), comprising: - the device for installing an elongated element (100) in a conduit (200) according to any one of claims 1 to 13, - a driving fluid supply unit, connected to the device for installing an elongated element (100) in a conduit (200) and arranged to supply the driving fluid under pressure to the driving fluid chamber (20), - a lubricant supply unit,connected to the device for installing an elongated element (100) in a conduit (200) and arranged to supply the lubricant under pressure to the lubricant chamber (30).

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