PILE-DRIVER AND METHOD FOR APPLICATION THEREOF

Abstract

A pile-driver is disclosed. The pile driver comprising a support member arranged in a transverse direction at or on a pile; a liquid chamber bounded on the underside by the support member and which further comprises one or more side walls and is configured to receive a liquid therein; one or more pressure build-up chambers, comprising: an upper part forming a combustion space; a lower part in fluid connection with the liquid chamber; an ignition mechanism configured to ignite a fuel present in the combustion space; and a fuel supply channel for carrying fuel into the combustion space; and a combustion product discharge channel for discharging combustion products after combustion; wherein the one or more pressure build-up chambers are arranged close to the side wall of the liquid chamber; and wherein the combustion product discharge channel is in fluid connection with a passage opening arranged in the side wall.

Claims

1. A pile-driver, comprising: a support member arranged or arrangeable in transverse direction at or on a pile; a liquid chamber which is bounded on the underside by the support member and which further comprises one or more side walls, the liquid chamber being configured to receive a liquid therein; one or more pressure build-up chambers, comprising: an upper part forming a combustion space; a lower part which is in fluid connection with the liquid chamber; an ignition mechanism configured to ignite a fuel present in the combustion space; and wherein the combustion space is configured to expand fuel present therein during combustion such that a pressure build-up takes place above the support member and the liquid present above the support member in the liquid chamber is displaced at least in upward direction away from the support member, and a downward force is exerted on the pile via the support member; a fuel supply channel for carrying fuel into the combustion space; a combustion product discharge channel for discharging combustion products after combustion; characterized in that the one or more pressure build-up chambers are arranged close to the one or more side walls of the liquid chamber; and the combustion product discharge channel is in fluid connection with a passage opening arranged in the one or more side walls.

2. The pile-driver as claimed in claim 1, wherein the one or more pressure build-up chambers are formed by one or more plate parts extending inward from the one or more side walls into the liquid chamber.

3. The pile-driver as claimed in claim 2, wherein the one or more plate parts extend in the direction of the support member.

4. The pile-driver as claimed in claim 2, wherein the liquid chamber has in top view a substantially round cross-section and the one or more pressure build-up chambers are formed by an annular plate part arranged around an inner periphery of the one or more side walls.

5. The pile-driver as claimed in claim 2, wherein the passage opening is arranged between the plate part and the support member.

6. The pile-driver as claimed in claim 1, wherein the combustion product discharge channel is provided with a shut-off valve which can be operated selectively by a controller.

7. The pile-driver as claimed in claim 1, wherein the one or more side walls of the liquid chamber separate the liquid from the surrounding area.

8. The pile-driver as claimed in claim 1, wherein the liquid present in the liquid chamber above the support member is water.

9. The pile-driver as claimed in claim 1, wherein the pile-driver is integrated into the pile, which forms with its side wall a side wall of the liquid chamber.

Description

[0029] Preferred embodiments of the present invention are further elucidated in the following description with reference to the drawing, in which:

[0030] FIG. 1 shows a view of an offshore wind turbine on a monopile construction;

[0031] FIG. 2 shows a perspective view of a pile-driver according to the invention;

[0032] FIGS. 3 and 4 show detailed cross-sectional views of a combustion product discharge channel for discharging combustion products in a closed state (FIG. 3) and open state (FIG. 4);

[0033] FIGS. 5-9 show cross-sectional views of successive stages during use of the pile-driver according to FIG. 2.

[0034] The offshore wind turbine 36 shown in FIG. 1 is a so-called monopile construction and comprises a pile 2 which is driven fixedly into the ground 40, formed by the seabed, below water level 38.

[0035] According to the invention this pile-driving is carried out with a pile-driver 1 as shown in FIG. 2. Pile-driver 1 comprises a support member 8 arranged or arrangeable in transverse direction at or on a pile 2, and a liquid chamber 5. Liquid chamber 5 is configured to receive a liquid therein and is bounded on the underside by support member 8 and further comprises one or more than one side wall 4. Pile-driver 1 further comprises one or more than one pressure build-up chamber 14, comprising an upper part 20 which forms a combustion space 22 and a lower part 24 which is in fluid connection with liquid chamber 5. An ignition mechanism 28 is configured to ignite a fuel present in combustion space 22, wherein combustion space 22 is configured to expand fuel present therein during combustion such that a pressure build-up takes place above support member 8 and the liquid present above support member 8 in liquid chamber 5 is displaced at least in upward direction away from support member 8, and a downward force is exerted on pile 2 via support member 8. Pile-driver 1 is further provided with a fuel supply channel 30 for carrying fuel into the combustion space, and a combustion product discharge channel 32 for discharging combustion products after combustion. The one or more than one pressure build-up chamber 14 of pile-driver 1 is arranged close to side wall 4 of liquid chamber 5, and combustion product discharge channel 32 is in fluid connection with a passage opening 6 arranged in side wall 4. An air supply channel 31 can further be provided, although it is also possible to envisage a combustible mixture of fuel and air being supplied to combustion space 22 through a fuel (mixture) supply channel 30.

[0036] Pressure build-up chamber 14 is formed by a one or more than one plate part 15 extending inward from the one or more than one side wall 4 into liquid chamber 5. In the embodiment of FIG. 2 pressure build-up chamber 14 is formed by an annular plate part 15 arranged around an inner periphery of side wall 4. Plate part 15 extends in the direction of support member 8 and thereby forms on the one hand a combustion space 22 and on the other a guide which deflects the downward falling medium in the direction of support member 8.

[0037] Passage opening 6 is arranged in side wall 4 between plate part 15 and support member 8 in order to enable discharge of the combustion products, i.e. combustion gases 33, from combustion space 22.

[0038] Combustion product discharge channel 32 is in fluid connection with this passage opening 6 arranged in side wall 4, and is further provided with a shut-off valve 35 which can be operated selectively by a controller 34. In FIG. 3 shut-off valve 35 of closing unit 27 is situated in a first state in which liquid chamber 5 is closed off from the surrounding area, while FIG. 4 shows a second state in which combustion products can be discharged via the shown arrow to the surrounding area through combustion product discharge channel 32.

[0039] FIG. 5 shows a starting situation wherein a pile-driver 1 is arranged on a pile 2 and is filled with a medium, typically water. The connection between pile-driver 1 and pile 2 takes place in the shown embodiment with a sleeve 9. A fuel is then introduced via a fuel supply channel 30 into combustion space 22 (FIG. 6). The fuel spreads through combustion space 22 and is then ignited with an ignition mechanism 28.

[0040] During an initial test a 22 metre water column 42 was raised about 1.5 metres as a result of the combustion. The medium is then in raised state for about 1 second (FIGS. 7 and 8). Controller 34 of closing unit 27 then opens shut-off valve 35 briefly: opening and closing each take about 0.1 second, and between the two actions shut-off valve 35 can be held open a further 0.5-0.6 second (FIG. 4). The overpressure of the combustion product, optionally assisted by the already downward moving medium, presses the combustion product to the surrounding atmosphere outside the pile-driver (FIG. 8). The medium can then fall onto the support member with greatly reduced gas spring effect of a possible residue of combustion products, wherein it drives pile 2 further into ground 40 (FIG. 9).

[0041] Side wall 4 separates the liquid in liquid chamber 5 from the surrounding area, wherein the liquid present in liquid chamber 5 above support member 8 is preferably water.

[0042] It is noted that a plurality of fuel supply channels 30, combustion gas discharge channels 32 and/or a plurality of ignition mechanisms 28 can be provided around the peripery of pile-driver 1. It is possible here to envisage a greater number of combustion gas discharge channels 32 being provided than the number of arranged fuel supply channels 30, since the time available for discharging combustion gases is limited. Five times as many combustion gas discharge channels 32 as fuel supply channels 30 can for instance thus be provided, for instance twenty combustion gas discharge channels 32 compared to four fuel supply channels 30.

[0043] Although not shown, the pile-driver can be integrated into pile 2, which forms with its side wall a side wall 4 of liquid chamber 5.

[0044] Although it shows a preferred embodiment of the invention, the above described embodiment is intended solely to illustrate the present invention and not to limit the scope of the invention in any way. When measures in the claims are followed by reference numerals, such reference numerals serve only to contribute toward understanding of the claims, but are in no way limitative of the scope of protection. The described rights are defined by the following claims, within the scope of which many modifications can be envisaged.