A tube installation or decommissioning device

Abstract

24 ABSTRACT The invention is directed to a tube installation or decommissioning device for use when installing a tube in a submerged mass of soil comprising of a frame which can either move axially along the exterior of the tube or move axially within the interior of 5 the tube to be installed or decommissioned. The frame is provided with one or more pumps each having an inlet for water and an outlet for pressurised water. The outlet for pressurised water of each of the one or more pumps is fluidly connected to a flexible water hose as present on a reel. 10 [Figure 11]

Description

[0001] A TUBE INSTALLATION OR DECOMMISSIONING DEVICE

[0002] The invention is directed to a tube installation or decommissioning device for use when installing or decommissioning a tube in or from a submerged mass of soil comprising of a frame which can move axially along the tube.

[0003] W02020 / 207903 describes a tube installation device for use to install a monopile for a wind turbine. The tube installation device as shown in Figures 8-11 of W02020 / 207903 consists of a ring shaped element having outlets for water nozzles directed upwards and downwards. The ring shaped element is further provided with vibration means. The insert has arms which connect the ring with a central body. The arms are slidably connected to the central body. The arms can vary in radial length by moving this slidable connection upwards and downwards along the central body. This allows the tube installation device to be fixed within and at the lower end of the monopile in an expanded position for use when installing the monopile. The arms can also be shortened resulting in an collapsed position allowing the tube installation device to be retracted from the monopile when the monopile is installed. In this manner the tube installation device can be reused for installing a next monopile.

[0004] W02023 / 062061 describes a monopile installation device having a central element and radially extending fixing means having a first position where the insert is fixed to the interior of the monopile and a second position where the insert can axially move within the monopile. At the lower end of the central element rotating arms are present which are provided with high pressure injection nozzles. The injection nozzles are provided with high pressure water via high pressure water conduits which run within the monopile and are guided by guiding means at the top of the monopile as shown in Figure 9 of this publication to externally positioned pumps on a floating vessel.

[0005] A problem with the prior art monopile inserts is that the water conduits for providing water to the nozzles will have to be very lengthy, requiring complex guiding means. The object of the present invention is to provide a less complex monopile installation device. This object is achieved with the following monopile installation device. Tube installation or decommissioning device for use when installing a tube in or decommissioning from a submerged mass of soil comprising of a frame which can either move axially along the exterior of the tube or move axially within the interior of the tube to be installed or decommissioned, wherein the frame is provided with one or more pumps each having an inlet for water and an outlet for pressurised water, wherein the outlet for pressurised water of each of the one or more pumps is fluidly connected to a flexible water hose, and wherein the frame is provided with a reel for each of the one or more flexible water hoses.

[0006] The tube installation or decommissioning device of this invention has the advantage that no lengthy water conduits are required which run within the monopile to an externally positioned pump or pumps. A further advantage is that these pumps do not have to be placed on an auxiliary vessel or vessels typically used when installing tubes from submerged mass of soil. This allows more simple and smaller vessels to be used. Because the tube installation device is provided with pumps it is possible to feed the pumps with the water present at the monopile when it is placed on or removed from for example a sea bed. To enable such a water feed to the pumps it is essential that the tube installation device remains above the mass of soil while the monopile is lowered or lifted. For this it is required that the tube installation device can freely move upwards, relative to the moving monopile. More advantages will be described when discussing the invention in more detail below.

[0007] Terms like higher, lower, above or below are used in this specification to more clearly describe the tube installation or decommissioning device and the tube or monopile in its orientation of actual end use. This does not mean that the scope of protection of the claims is limited to this orientation.

[0008] The invention is directed to a tube installation or decommissioning device. Preferred is a device which can be used for both installation and decommissioning. When reference is made below preferred features and use of a tube installation device it is understood that these preferred features can also be the preferred features and use of a tube decommissioning device according to the invention.

[0009] The submerged mass of soil may be the bottom of a lake. Preferably the submerged mass of soil is the sea bed. When reference is made to the sea bed in this specification it refers to the soil surface, i.e. the interface of the mass of soil and the mass of water. Whenever sea bed is used in this specification also the bottom of a lake is meant.

[0010] The tube may be any tube which is to be installed in or decommissioned from a submerged mass of soil. For example the tube may be piles suited to support a jacket foundation for a wind turbine. The device can be advantageously be used in a so-called pre-piling method where the piles are installed first and wherein the jacket legs are placed in the installed piles. Preferably the device is used to install or decommission a monopile.

[0011] A tube installation device suited for a pile of a jacket foundation may be provided with one or two pumps while a tube installation device suited for a monopile may be provided with 2 to 6 pumps. The number of pumps may depend on the available pump capacity and on the required volume of water to be supplied to the water nozzles. The inlet for water may be at the pump or close to the pump. As the tube installation device will in use be submerged or partly submerged it is conceived that the pump itself will also be submerged or close to the water level. This allows that either the inlet for water of the pump itself is submerged or that an optional supply conduit to the inlet for water of the pump can be very short. This short supply conduit or hose will have an inlet which is submerged. The inlet for water of the pump or of the very short supply conduit is preferably positioned at the upper part of the frame because at a higher elevation the water will contain less soil particles. Soil particles will be present in the water as a result of the tube installation process. For this reason the pumps are suitably provided with sieves or other means to remove such soil particles entering the pumps. The water as supplied to the pumps is preferably sieved to avoid particles to enter the pump.

[0012] The pumps are preferably electrically powered or hydraulically powered. The tube installation device is preferably used in combination with a multitude of water nozzles as positioned at or close to a circular lower end of the tube. Examples of such water nozzles are described in WO2023217721 , EP3561181 , W02020207903 and WO9815692. For this the outlet for pressurised water of each of the one or more pumps is fluidly connected to a flexible water hose. These flexible water hoses are used to transport pressurised water from the pumps to the nozzles. The flexible water hoses are further advantageous because they can be easily reeled in and reeled out to accommodate the varying distance between the device and the water nozzles when using the device. For this the frame is provided with a reel for each of the one or more flexible water hoses as connected to the one or more pumps. The flexible water hose may be a 2” to 6” or a 4"-6" diameter steel or fibre reinforced hose.

[0013] Preferably the pump connected to a reel is present within a substantially tubular inner space of the reel. This simplifies the connection between the pump and the reel and further makes the pump and reel combination more compact.

[0014] The tube installation device can either move axially along the exterior of the tube or move axially within the interior of the tube to be installed or decommissioned. The tube will then be in its vertical position and the tube installation device is preferably suspended by one or more cables, which cables can be increased or decreased in length. These cables may be connected at its upper end to the upper end of the tube or to an optional vibrating device as will be described below. Preferably a winch is present at one end of the suspension cable enabling axial movement of the tube installation device along the interior or exterior of the monopile. Preferably the winch is present on the frame of the device because this avoids having to adapt the optional vibrating device.

[0015] The tube installation device may in use be at or below the water level. Preferably the tube installation device is positioned as close to the soil level as possible such to limit the required length of the water hoses. In order to relieve the tension in the suspension cable or cables from which the device is suspended it may be advantageous to provide the device with buoyancy means. Such means, for example a container fixed to the frame, can be filled with air or any other gas to increase the buoyancy of the monopile installation device. The buoyancy means may also be inflatable buoyancy means, like for example inflatable bags.

[0016] In a first embodiment of the invention the frame of the tube installation device can move axially along the exterior of the monopile. Such a frame may be positioned along one side of the monopile. Preferably the frame has a shape which enables the frame to surround the monopile. For example the ring shaped frame may be a clam shell frame having two clam shell arced parts connected at one of their respective ends by means of a pivot and at their other respective ends by a closing arrangement. The claim shell frame has an open position allowing the frame to be placed around the exterior of the monopile and a closed position where it surrounds the exterior of the monopile. A ring shaped frame may also be a fully closed rig shaped frame which will then have to be placed from above the monopile. For example such a ring shaped frame may be suspended by cables from a vibrating device. The ring shaped frame as suspended from the vibrating device can be positioned together on top of the monopile by use of a crane.

[0017] In a second embodiment the frame of the tube installation device can move axially along the interior of the tube. The tube installation device of this second embodiment may be advantageously used to install a monopile having a tubular upper part having a smaller diameter than the diameter of the tubular lower part. For such use it is preferred that the tube installation device can adopt an radially expanded position and a radially collapsed position. In the radially expanded position the tube installation device may be substantially centred within the tubular lower part of the monopile. In the radially collapsed position the tube installation device may be axially moved through the tubular upper part. This allows to place and more preferably retrieve the tube installation device after the monopile is installed.

[0018] The radially expanded and collapsed position of the tube installation device may be achieved by radially extending arms. These arms may for example be pivotally connected to the frame or may be in length variable arms, like for example actuators. The arms are preferably guiding means for the water hoses to guide the water hose from the more central positioned pump to the interior side of the wall of the monopile. Preferably the guiding means are present which guide a flexible water hose from the outlet for pressurised water of each of the one or more pumps to a radially outward position and wherein these guiding means are moveably connected to the frame such that the device can adopt the radially expanded position when the guiding means are in a radially expanded position and can adopt the radially collapsed position when the guiding means are in a radially collapsed position.

[0019] The tube installation device in its expanded position is preferably positioned in a monopile on shore when used as a tube installation device. The monopile will then be in its horizontal position. The water hoses of the tube installation device are suitably connected to the waterjets. This arrangement of monopile and tube installation device may then be transported in their horizontal or vertical position to the installation site.

[0020] The invention is therefore also directed to a monopile having a tubular lower part, a tubular upper part and a circular lower end and comprising a tube installation device according to this invention positioned within the monopile. The outlet for pressurised water of each of the one or more pumps is suitably fluidly connected to a multitude of water nozzles as positioned at or close to the circular lower end. This connection is preferably by means of a flexible water hose.

[0021] The monopile suitably has a tubular lower part having a cylindrical and flush outer wall surface. Further the tubular lower part may be provided with one or more openings. Preferably at an elevation which remains above the soil surface, or sea bed, when installing. These openings may be an opening or openings which, when the monopile is installed, are also used to pass power cables and other connections required for the wind turbine. When performing the installation method according to this invention the excess soil suspension will suitably flow through these openings.

[0022] The monopile suitably has a tubular upper part having a smaller diameter than the diameter of the tubular lower part. A transition part having a frusto-conical shape may then be positioned below the tubular part having the smaller diameter. Such a shape for a monopile for a wind turbine is well known. The monopile has a lower zone and wherein the lower zone preferably has a cylindrical and flush outer surface and a cylindrical and flush inner surface. This simplifies the design.

[0023] The monopile for a wind turbine is suitably the part of the wind turbine which just extends above the water level. By just extending is suitable meant between 5 and 20 m extending above the water level when installed. On top of the monopile a mast is typically mounted and a wind turbine generator. The distance of penetration of the monopile in the soil is suitably between 10 and 50 m and preferably below 40 m.

[0024] The monopile is suitably provided with a multitude of water nozzles as positioned at or close to a circular lower end of the monopile and suitably at the inner side of the tubular lower part of the monopile. The water nozzles are positioned at or near to the lower end and directed to inject a flow of water under a downward angle with the horizontal. The water nozzles are suitably part of a manifold which is fed by the water from a flexible water hose or a rigid conduit as described elsewhere. More than one flexible water hose or rigid conduit can feed one manifold. The manifold may be circular or have the shape of an arc, where a multitude of arced manifolds for a circle along the inner wall of the tubular lower part.

[0025] The manifold or manifolds may be permanently fixed, for example by welding or bolting, to the inner side of the tubular lower part. Alternatively, the manifolds may be detachably connected to the tubular lower part. Preferably the manifolds are permanently fixed by welding.

[0026] Preferably the water nozzles are directed to the lower end under an angle of between zero and 90 degrees with the horizontal, preferably between 10 and 80 degrees, more preferably between 20 and 70 degrees and most preferably between 30 and 60 degrees with the horizontal. The direction will have an axial directional component and a tangential directional component. The direction may also have a small inwardly radial component such that the jets of water flow free of a neighbouring jet of water. The water nozzles may be positioned at the lower end of the tubular lower part. Preferably the water nozzles are positioned at a distance from the lower end. The distance at which the water nozzles are positioned from the lower end is suitably between 0.1 and 5 m, preferably between 0.25 and 3 m. Because the water nozzles are positioned in a circle the distance of each nozzle to the lower end is about the same. The distance is defined as the axial distance between the lower end and the outlet openings for the water of the water nozzles. It has been found that the optimal distance at which the water nozzles are positioned above the lower end relates to the type of soil and the ability of a waterjet exiting from a nozzle of the water nozzles to penetrate the soil. Optimally the waterjets penetrate the soil to the level of the lower end of the monopile. In this way an optimal disturbance and soil suspension formation is achieved in this region to enhance the penetration of the monopile into the soil while avoiding that significant amounts of water can escape to the surroundings of the monopile as explained above. This distance will be higher for easy to penetrate soil types such as sand and lower for difficult to penetrate soil types, like clay. The distance will also depend on the diameter of the lower end part of the monopile. The distance may be higher for larger monopiles because more water may have to be injected resulting in a higher penetration length. Further the angle at which the water is injected will influence this distance. When the angle is near zero degrees with the horizontal a relatively small distance will be chosen while when the direction becomes more downward a larger distance will be chosen. The distance can be easily determined by measuring a single penetration depth of a jet exiting a nozzle under design conditions in a soil type for which the monopile is to be designed. The distance will then be a function of the angle and the measured penetration depth. The monopile is thus preferably designed for a specific type of soil in which it is to be positioned wherein the distance between the nozzles and the lower end is determined by the type of soil, the direction of the nozzles and the diameter of the lower end part of the monopile.

[0027] The number of injection nozzles will depend on the diameter of the tubular lower part and on the soil type, wherein a more penetrable soil type allows a larger distance between the nozzles. For example for a sandy soil type the distance between two nozzles may be around 150 mm while for a monopile having the same dimensions the distance for a clay soil type may be around 100 mm. The outlet for pressurised water of each of the one or more pumps is fluidly connected to the multitude of water nozzles via a flexible water hose. The flexible water hoses preferably run along the internal wall of the monopile from the multitude of water nozzles to the radially extended guiding means of the tube installation device.

[0028] Preferably a multitude of water nozzles are present in two or more separate manifolds, each manifold feeding a part of the multitude of water nozzles and wherein each manifold is fluidly connected to at least one flexible water hose. The water hose is preferably detachably connected to the manifold. This allows that the flexible water hose can be retrieved from the monopile together with the tube installation device after installing the monopile. Detaching the water hose from the manifold can be performed by a mechanical and / or hydraulically operated decoupling.

[0029] More preferably the tube installation device is lowered into a vertically positioned monopile where it connects to the above described multitude of water nozzles as positioned at or close to the circular lower end of the monopile. The downstream ends of the flexible water hoses of the tube installation device may connect with the waterjets or more especially to the water inlet openings of the manifold or manifolds. In this embodiment the monopile provided with the nozzles or more especially the manifold or manifolds are assembled on shore before being transported in their horizontal or vertical position to the installation site. At the installation site the monopile may be vertically positioned on the sea bed. The tube installation device, for example in its collapsed position, may then be lowered into the vertically positioned monopile for use in a method for installing the monopile as here discussed. After installation the downstream ends of the flexible water hoses of the tube installation device may disconnect after which the tube installation device may be retrieved from the installed monopile for use in a method to install a different monopile.

[0030] When the monopile is vertically positioned the tube installation device is suitably suspended by means of a cable. The cable is connected to the monopile at a higher elevation than the position of the tube installation device or connected to a detachable device present at the upper end of the monopile. This cable is suitably further equipped to provide hydraulic and / or electrical power to the tube installation device. The hydraulic and / or electrical power may be used to run the pumps, bring the device in its expanded or collapsed position, operate the winch hydraulically decouple the water hose from the manifold. The cable is suitably also provided with means to control the device. Further control means may be present as part of the tube installation device.

[0031] When the monopile is vertically positioned it is preferred that a means to generate a vibration is attached to the upper end of the monopile. Such means may be a vibratory hammer or an impact hammer, a gentle driving of piles (GDP) or by the pile-driver assembly described in US2022349144. Preferably the tube installation device is suspended by one or more cables from the means to generate a vibration. Preferably only one cable is used which combines suspension and the other functions.

[0032] The invention is also directed to a method for installing a monopile having a tubular lower part and a circular lower end in a soil surface covered by a mass of water by vertically positioning the tubular lower part of a monopile according to the invention as described above and in the figures on the soil surface such that the inlet for water of the one or more pumps are submerged in the mass of water, pumping water by the pumps from within the monopile via the inlet for water of one or more pumps to the nozzles resulting in that water ejects at the lower end resulting in that the ejected water penetrates the soil resulting in a soil suspension of water and soil particles which soil suspension spirals upwardly within the tubular lower part monopile and resulting in a lowering of the monopile into the soil, and wherein the tube installation device is continuously or intermittently vertically moved within the monopile to ensure that the inlets of the one or more pumps remains at a position above the soil surface and below the water level of the mass of water, wherein the distance between the tube installation device and the multitude of water nozzles increases. Preferably part of the flexible hoses are unreeled from a reel to accommodate the increased distance between the tube installation device and the multitude of water nozzles increases.

[0033] Preferably the pressure within the tubular lower part relative to the pressure in the mass of water surrounding the tubular lower part is balanced by flowing part of the soil suspension from within the tubular lower part via one or more openings in the tubular lower part to the mass of water surrounding the tubular lower part and wherein the one or more openings remain above the soil surface while performing the method.

[0034] In order to achieve a optimal penetration into the soil it has been found that the majority of the water, preferably more than 80 vol%, more preferably more than 90 vol% and most preferred all of the water is injected under a downward angle with the horizontal direction. It has been found that there is no additional benefit of having injection nozzles directed horizontally to upwardly as in the prior art designs.

[0035] In the method of this invention it is thus preferred that the water which is ejected does not substantially penetrate the soil to a level below the lower end of the monopile. Preferably the injection nozzles are positioned at a distance from the lower end, as described above, such that the water which is ejected does not substantially penetrate the soil to a level below the lower end of the monopile. Further it is preferred that more than 90 vol% of the water ejected from the injection nozzles is discharged via the one or more openings to the mass of water surrounding the tubular lower part as a result of balancing the pressure.

[0036] The amount of water as ejected at the lower end part of the monopile will suitably depend on the soil type and dimensions of the monopile. For sand type of soils, a high flow and low water pressure is preferred while for clay type soils a low flow and high pressure is preferred. This results in that for a sand type of soil substantially all of the soil within the monopile is present as a volume of fluidised soil, i.e. a suspension. For a clay type of soil a suspension will be present in an annulus against the inner wall and a more dense inner core of clay will be present in the centre of the monopile. To give an indication for a monopile having a diameter of the lower end part of between 4 and 15 meter a flow of water is preferably between 1000 and 100000 l / min. For a 8 meter diameter monopile this flow may be between 6000 and 30000 l / min. At the start of the method lower flows of water may be applied, which flow will then increase to the listed ranges when the monopile penetrates the soil.

[0037] Preferably the water nozzles are positioned at a distance from the circular lower end such that the water which is ejected does not substantially penetrate the soil to a level below the circular lower end of the monopile.

[0038] Preferably the one or more openings remain above the soil surface while performing the method for at least 1 m.

[0039] In the method of this invention it is preferred to generate a vibration at the upper end of the monopile to reduce the friction between the soil and the outer surface of the monopile and the soil resistance at the lower end of the tubular lower part. Applicants found that by providing the waterjets at the lower part of the monopile according to this invention and a vibration to the upper end of the monopile a favourable penetration of the monopile is achieved in many types of soil. The water jets may achieve up to a 70% or higher strain reduction as compared to when for example only a vibrohammer would be used to drive the monopile into the soil. The reduction of strain is also a measure of noise reduction. It is believed that the water jets achieve a significant reduction or even removal of the friction at the inner side of the monopile. The generation of vibrations may be achieved by various methods. Known methods are achieved by the earlier mentioned means for generating a vibration.

[0040] After the monopile is installed the tube installation device is suitably removed from the monopile by vertically lifting the tube installation device within the monopile while the tube installation device is in its radially collapsed position. In this way it can pass the narrower upper part of the monopile.

[0041] After the monopile is installed the flexible water hose is suitably disconnected from the manifold. In this way it can be removed from the monopile together with the tube installation device. Preferably the water hoses are reeled in when removing the tube installation device.

[0042] The flexible water hose is suitably reeled in as much as possible. When installing the monopile the distance between the tube installation device and the nozzles will become greater. To accommodate the larger distance the flexible water hose are reeled off from the reel.

[0043] The invention will be illustrated by the following non-limiting Figures.

[0044] Figure 1 shows a tube installation device (1 ) of this invention having a frame (2) in its expanded position and provided with four pumps (3). The pumps (3) have an inlet (4) for water and an outlet (5) for pressurised water. The inlet (4) for water is present in the upper end (6) of the frame (2) as shown. The outlet (5) for pressurised water of each of the four pumps is fluidly connected to a flexible water hose (7). Each flexible water hose (7) is present in a reel (8). The water hose (7) runs from reel (8) via guiding means (9) to a radially outer position. The guiding means (9) are moveably connected to the frame (2) such that the device (1 ) can adopt the radially expanded position when the guiding means (9) are in a radially expanded position and can adopt the radially collapsed position when the guiding means (9) are in a radially collapsed position. Guiding means (9) consist of an arm (10) which can pivot around axle (11 ) and is operated by actuators (12) and (13). A winch (14) for a suspension cable (not shown) is present at the upper part (6) of frame (2).

[0045] Figure 2 shows the device (1 ) of Figure 1 from below.

[0046] Figure 3 shows the device (1 ) of Figure 1 from aside in a 3D view.

[0047] Figure 4 shows a cross-section of a monopile (19) according to the invention having a tubular lower part (20), a tubular upper part (21 ) and a circular lower end (22). A tube installation device (1 ) of figures 1 -5 is positioned within the monopile. The monopile (19) has partly penetrated a sea bed (23). The tube installation device (1 ) and the inlets (4) of pumps (3) are positioned below the water level (24). Because the interior of the monopile is in fluid communication with the water surrounding the monopile via one or more openings (26) in the wall (25) of the monopile the water level (24) is substantially the same within and outside the monopile. Monopile (19) has a tubular upper part (21 ) having a smaller diameter than the diameter of the tubular lower part (20). Between lower and upper part a frusto conical transition part (27) is shown. A multitude of water nozzles are present in two or more separate manifolds (28). Arrows (29) illustrate the resulting waterjets from the water nozzles when in use. The two or more manifolds (28) are fluidly connected to flexible water hose (7) of which 3 of the 4 water hoses (7) are shown in this view.

[0048] As shown the guiding means (9) of device (1) are in their radially expanded position such that the one or more flexible water hoses (7) run from the guiding means (9) along the inner wall (30) of the monopile (19) to the multitude of water nozzles as present in manifolds (28). The guiding means (9) are provided with rubber blocks (31 ) to protect the device against hard collisions against the inner wall (30) while at the same time the device is centred within the monopile (19). The dimensions of the device (1 ) and the properties of blocks (31 ) are such that the device can freely move in an axial direction within the monopile.

[0049] The tube installation device (1 ) in the vertically positioned monopile (19) is suspended by means of a cable (32). Cable (32) is connected to a vibratory hammer (33) as present at the upper end of the monopile (19).

[0050] The pumps of device (1 ) pump water from within the monopile via the inlet for water of one or more pumps to the nozzles resulting in that water ejects (29) at the lower end (22) resulting in that the ejected water penetrates the soil of the sea bed (23) resulting in a soil suspension of water and soil particles. The soil suspension spirals upwardly within the tubular lower part (20) of the monopile (19). The ejection of water and the vibration results in a lowering of the monopile (19) into the soil of sea bed (23) resulting in a situation shown in Figure 7.

[0051] Figure 5 shows the monopile (19) of Figure 4 with the difference that the monopile is more penetrated into the sea bed (23). Between the situation of Figure 6 and the situation of Figure 7 the tube installation device (1 ) is continuously or intermittently vertically moved within the monopile (19) to ensure that the inlets (4) of the one or more pumps (3) remains at a position above the soil surface or sea bed (23) and below the water level (24) of the mass of water. The distance between the tube installation device (1 ) and the multitude of water nozzles at the manifold (28) increases as shown when comparing Figure 6 and 7. The tube installation device (1 ) is axially moved towards the vibratory hammer (33) as present at the upper end of the monopile (19) by shortening suspension cable (32).

[0052] Figure 6 shows an installed monopile (19) where the tube installation device is in its collapsed position. The flexible water hoses (8) are disconnected from the manifolds (28) and reeled in. The collapsed tube instillation device (1) is axially moved upwards by shortening suspension cable (32) to pass through the narrower a tubular upper part (21 ). When the device reaches the vibratory hammer (33) the combined vibratory hammer and tube installation device may be lifted from the installed monopile (19) for reuse in a method to install another monopile.

[0053] Figure 7 shows a monopile (19) provided with manifolds (28) as in Figures 4-6. A water supply conduit (34) runs upward along the inner wall (30) of the monopile (19) to a point a slot (35) in the wall of the monopile (19). This slot is connected to a flexible water hose (36) which is connected to an externally positioned tube installation device (37). The tube installation device (37) is comprised of a submerged circular frame (38) provided with pumps (3) having a submerged inlet (4) for water. The outlet (5) for pressurised water of the pump is connected to the flexible water hose (36). The tube installation device (37) is further comprised of a floating circular frame (39) connected to the submerged frame (38) by in length variable cables (40). In use the in length variable cables (40) will increase in length keeping the pumps (3) at substantially the same elevation of slot (35). The cables are for this reason provided with a winch (41 ) on the floating circular frame (39). The circular frames (38) and (39) may have a clamshell design allowing the frames to be positioned around a monopile while the monopile rests on the sea bed at the start of the installation. When the monopile is installed the flexible water hose can be disconnected at slot (35) and the submerged frame (38) can be lifted towards the floating frame (39) by means of cables (40). Figure 8 shows a preferred tube installation device (50) for the tube installation device (1 ) of Figures 1-3. The tube installation device (50) has a frame (2). Two pair of reels (8) are shown positioned axially above each other within the frame (2). Within a substantially tubular inner space of a pair of two reels (8) a pump (3) is present for each of the two water hoses (7) as present on the pair of a reel (8). The first pair of reels have a first common axis of rotation and is positioned within the frame above the second pair of reels having a second common axis of rotation as seen from above. A flexible water hose (7) is present in a reel (8). The water hose (7) runs from reel (8) via guiding means (9) to a radially outer position. The downstream ends of the flexible hose (7) is provided with a rigid member (52) enabling easier connecting with the corresponding inlet openings of a manifold provided with nozzles.

[0054] The guiding means (9) are moveably connected to the frame (2) by an arm (10) such that the device (50) can adopt the radially expanded position when the guiding means (9) are in a radially expanded position as shown and can adopt the radially collapsed position when the guiding means (9) are in a radially collapsed position. Two winches (14) for a suspension cable (53) is present at the upper part (6) of frame (2). A reel (54) is shown for a hydraulic conduit (55). The hydraulic conduit (55) serves to power the four hydraulic pumps (3).

[0055] Figure 9 shows the device (50) from above in its expanded position. This view more clearly shows that the guiding means (9) are further provided with a guiding wheel (51 ) which can guide the tube installation device (50) along the inner wall of the monopile when it axially moves within the monopile. Because the direction of the first common axis is perpendicular to the direction of the second common axis as seen from above a device is provided having four equally spaced guiding means wheels (51 ) at the comers of an imaginary square which can effectively move the device (50) axially within a monopile.

[0056] In Figure 10 a detail of the device of Figure 8 in its collapsed position is shown wherein guiding means (9) is shown in its collapsed position (9b). The guiding means (9) are now within the frame (2) and do not extend to the exterior of the frame enabling the tube installation device to move through the tubular upper part of a monopile having a smaller diameter than the diameter of the tubular lower part of the monopile.

[0057] Figure 11 shows the device (50) of Figure 8 in a three dimensional view from slightly above showing how guiding means (9) are connected to the frame (2) by an arm (10) which can pivot around axle (11 ).

[0058] The invention is especially directed to a tube installation device illustrated by Figures 8-11 , wherein a first pair of reels having a first common axis of rotation is positioned above a second pair of reels having a second common axis of rotation within the frame, wherein the water hoses of the first pair of reels are fluidly connected to the outlet for pressurised water of one or two pumps as present within the substantially tubular inner space of the first pair of reels and wherein the water hoses of the second pair of reels are fluidly connected to the outlet for pressurised water of one or two pumps as present within the substantially tubular inner space of the second pair of reels and wherein the direction of the first common axis is perpendicular to the direction of the second common axis as seen from above. Preferably the frame is further provided with a reel for a hydraulic conduit positioned above the first pair of reels and wherein the pumps are hydraulically powered pumps.

Claims

CLAIMS1 A tube installation or decommissioning device for use when installing a tube in or decommissioning from a submerged mass of soil comprising of a frame which can either move axially along the exterior of the tube or move axially within the interior of the tube to be installed or decommissioned, wherein the frame is provided with one or more pumps each having an inlet for water and an outlet for pressurised water, wherein the outlet for pressurised water of each of the one or more pumps is fluidly connected to a flexible water hose, and wherein the frame is provided with a reel for each of the one or more flexible water hoses.

2. The tube installation or decommissioning device according to claim 1 , wherein the outlet for pressurised water of a pump is connected to a reel and wherein the pump is present within a substantially tubular inner space of the reel.

3. The tube installation or decommissioning device according to claim 2, wherein a first pair of reels having a first common axis of rotation is positioned above a second pair of reels having a second common axis of rotation within the frame, wherein the water hoses of the first pair of reels are fluidly connected to the outlet for pressurised water of one or two pumps as present within the substantially tubular inner space of the first pair of reels and wherein the water hoses of the second pair of reels are fluidly connected to the outlet for pressurised water of one or two pumps as present within the substantially tubular inner space of the second pair of reels and wherein the direction of the first common axis is perpendicular to the direction of the second common axis as seen from above.

4. The tube installation or decommissioning device according to claim 3, wherein the frame is further provided with a reel for a hydraulic conduit positioned above the first pair of reels and wherein the pumps are hydraulically powered pumps.

5. The tube installation or decommissioning device according to any one of claims 1-4, wherein the frame is provided with a winch suited to winch in or out a suspension cable.

6. The tube installation or decommissioning device according to any one of claims 1 -5, wherein the inlet for water of the one or more pumps is present in the upper part of the frame.

7. The tube installation or decommissioning device according to any one of claims 1-6, wherein the frame is further provided with buoyancy means.

8. The tube installation or decommissioning device according to claim 7, wherein the buoyancy means are inflatable buoyancy means.

9. The tube installation or decommissioning device according to any one of claims 1-2, wherein the frame can move axially along the exterior of the tube.

10. The tube installation or decommissioning device according to claim 9, wherein the frame has a circular opening for passage of the tube to be installed or decommissioned and wherein guiding means are present at the inner side of this opening to allow an axial movement along the exterior of the tube.11 . The tube installation or decommissioning device according to any one of claims 9-10, wherein the frame is a clam shell frame having two clam shell arced parts connected at one of their respective ends by means of a pivot and at their other respective ends by a closing arrangement and wherein the claim shell frame has an open position allowing the frame to be placed around the exterior of the monopile and a closed position where it surrounds the exterior of the monopile.

12. The tube installation or decommissioning device according to any one of claims 1 -8, wherein the frame can move axially along the interior of the monopile.

13. The tube installation or decommissioning device according to claim 12, wherein the device can adopt an radially expanded position and a radially collapsed position.

14. The tube installation or decommissioning device according to claim 13, wherein the guiding means are present which guide a flexible water hose from the outlet for pressurised water of each of the one or more pumps to a radially outward position and wherein these guiding means are moveably connected to the frame such that the device can adopt the radially expanded position when the guiding means are in a radially expanded position and can adopt the radially collapsed position when the guiding means are in a radially collapsed position.

15. The tube installation or decommissioning device according to any one of the previous claims wherein the device is a tube installation and decommissioning device.

16. A monopile having a tubular lower part, a tubular upper part and a circular lower end and comprising a tube installation or decommissioning device according to any one of claims 12-15 positioned within the monopile.

17. The monopile according to claim 16, wherein the outlet for pressurised water of each of the one or more pumps is fluidly connected to a multitude of water nozzles as positioned at or close to the circular lower end.

18. The monopile according to claim 17, wherein the tube installation or decommissioning device is according to claim 14 having the guiding means in the radially expanded position such that the one or more flexible water hoses run from the guiding means along the inner wall of the monopile to the multitude of water nozzles.

19. The monopile according to any one of claims 17-18, wherein the flexible water hose is connected to the outlet for pressurised water at its upstream end and detachably connected to the nozzles at its downstream end.

20. The monopile according to any one of claims 17-19, wherein the multitude of water nozzles are present in two or more separate manifolds, each manifold feeding a part of the multitude of water nozzles and wherein each manifold is fluidly connected and optionally detachably connected to at least one flexible water hose.21 . The monopile according to any one of claims 16-20, wherein the monopile has a tubular upper part having a smaller diameter than the diameter of the tubular lower part.22 The monopile according to any one of claims 16-21 , wherein the monopile is vertically positioned and wherein tube installation or decommissioning device is suspended by means of a cable and wherein the cable is connected to the monopile at a higher elevation than the position of the tube installation device or connected to a detachable device present at the upper end of the monopile.

23. The monopile according to claim 22, wherein the cable is further equipped to provide hydraulic and / or electrical power to the tube installation or decommissioning device.

24. The monopile according to clam 23, wherein the cable is further equipped to control the tube installation or decommissioning device.

25. The monopile according to any one of claims 16-24, wherein the monopile is vertically positioned and wherein a means to generate a vibration is attached to the upper end of the monopile.

26. The monopile according to claim 25, wherein the means to generate a vibration is a vibratory hammer or an impact hammer.

27. A method for installing a monopile having a tubular lower part and a circular lower end in a soil surface covered by a mass of water byvertically positioning the tubular lower part of a monopile according to any one of claims 17-26 on the soil surface such that the inlet for water of the one or more pumps are submerged in the mass of water, pumping water by the pumps from within the monopile via the inlet for water of one or more pumps to the nozzles resulting in that water ejects at the lower end resulting in that the ejected water penetrates the soil resulting in a soil suspension of water and soil particles which soil suspension spirals upwardly within the tubular lower part monopile and resulting in a lowering of the monopile into the soil, and wherein the tube installation device is continuously or intermittently vertically moved within the monopile to ensure that the inlets of the one or more pumps remains at a position above the soil surface and below the water level of the mass of water, wherein the distance between the tube installation device and the multitude of water nozzles increases.

28. The method according to claim 27, wherein the tube installation device is according to claim 3 and wherein part of the flexible hoses are unreeled from the reel to accommodate the increased distance between the monopile insert and the multitude of water nozzles.

29. The method according to any one of claims 27-28, wherein the pressure within the tubular lower part relative to the pressure in the mass of water surrounding the tubular lower part is balanced by flowing part of the soil suspension from within the tubular lower part via one or more openings in the tubular lower part to the mass of water surrounding the tubular lower part and wherein the one or more openings remain above the soil surface while performing the method.

30. The method according to claim 29, wherein more than 90 vol% of the water ejected from the nozzles is discharged via the one or more openings to the mass of water surrounding the tubular lower part as a result of balancing the pressure.31 . The method according to any one claims 27-30, wherein the diameter of tubular lower part is between 4 and 15 m and wherein between 1000 and 100000 l / minof water is ejected from the water nozzles.

32. The method according to any one of claims 27-31 , wherein the nozzles are positioned at a distance from the circular lower end such that the water which is ejected does not substantially penetrate the soil to a level below the circular lower end of the monopile.

33. The method according to any one of claims 27-32, wherein the one or more openings remain above the soil surface while performing the method for at least 1 m.

34. The method according to any one of claims 27-33, wherein at the upper end of the monopile a vibration is generated.

35. The method according to anyone of claims 27-34, wherein the tube installation device is according to claim 13 and wherein after the monopile is installed the tube installation device is removed from the monopile by vertically lifting the tube installation device within the monopile while the tube installation device is in its radially collapsed position.

36. The method according to claim 35, wherein the flexible water hose is connected to the outlet for pressurised water at its upstream end and detachably connected to a manifold feeding the nozzles at its downstream end and wherein the flexible water hoses are detached from the manifold and removed from the monopile together with the tube installation device.

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