GB2112327A

GB2112327A - Hopper suction dredger

Info

Publication number: GB2112327A
Application number: GB08227625A
Authority: GB
Inventors: Heiko Stehmeier
Original assignee: O&K Orenstein and Koppel GmbH
Current assignee: CNH Industrial Baumaschinen GmbH
Priority date: 1981-09-29
Filing date: 1982-09-28
Publication date: 1983-07-20
Also published as: DE3139492C2; FI71279B; JPS58139890A; NL8203430A; FI71279C; FI823175L; DE3139492A1; FI823175A0; CA1185995A

Abstract

A hopper suction dredger has one or more slits (5) provided in its hull. Each slit (5) is open at its base and receives a auction tube (1) therein. The suction tube (1) can be raised and lowered by an associated winch (6) housed in the slit (5) or in a cell (7) to which access is had by way of a shaft (8). Each suction tube (1) is arranged to convey dredged material to the hopper (4) of the dredger. The hopper may have overflow connections to the slits. <IMAGE>

Description

SPECIFICATION Hopper suction dredger The present invention relates to a hopper suction dredger.

Hopper suction dredgers are used to make and to maintain navigable waterways with a desired depth of water. One or more suction tubes lowered laterally from the ship's side are arranged to convey dissolved earth into the hopper of the vessel. In this respect, a feed pump is associated with each suction tube to provide the conveying capacity. The feed pump may be installed as a submerged pump in the suction tube or in the ship. Above the water line, a conveyer leading into the hopper is connected to each section tube.

Such a dredger is described in 0. s K. Prospectus Number 045/138 dX 10876.

The system of waterways used throughout the world increasingly includes regions in which the navigable waterways are covered with ice over a large part of the year. However, it is necessary, even here, to ensure that the predetermined depth of water required for navigation is available.

The hopper suction dredgers known hitherto with suction tubes lowered laterally are unsuitable for jobs of this kind.

It is an object of the invention to provide a hopper suction dredger which can be used for icebreaking.

According to the present invention there is provided a hopper suction dredger characterized in that in the ship's hull one or more slits are provided for providing one or more suction tubes, the or each said slit being open at the bottom.

During movement of a dredger of the invention the or each suction tube, and the associated suspension ropes, are located in the ice-free region of the ship. This results in a considerable reduction in the travelling resistance and in an energy saving. There is no need to provide lateral protective booms to protect the suction-tube suspension ropes in the region of the ice.

Furthermore, a suction tube can be mounted on both sides in the elbow region. As a result of this tensile forces only arise in the mounting and in the suction tube, whereas in the case of a lateral overhung mounting means bending forces would arise to a disadvantage in the suction tube and in the outer skin, especially during movement through ice. If the winches for lifting and lowering the suction tubes are located above the slits described, then there is no need for special suction-tube booms and the number of mechanical parts is reduced. If the winches are installed in a self-contained empty cell, they are also protected from being covered with ice.

An embodiment of the present invention will hereinafter be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a cross-section of a hopper suction dredger; Figure 2 shows a longitudinal section of the dredger of Figure 1, and Figure 3 shows a plan view of the dredger.

Figure 1 shows a cross-section of a dredger having suction tubes 1 which can be lowered by means of winches 6. The suction tubes can be provided in a known manner with suction heads a submerged pump, and/or pressure activation.

The suction tubes 1 themselves are each located in a slit 5 in the ship's hull. Each slit 5 has a bottom open downwardly. The vessel can also be constructed with a slit which extends up to the main deck and is open at the top, and the winches can then be mounted directly above the slit.

However, it is also possible, as may be seen in the drawing, to locate the winches in empty cells 7 above the slits and separated from them by a ceiling. Access to the empty cells 7 is gained through shafts 8 which can be closed by hatch covers 9. The arrangement and dimensions of these shafts 8 can be chosen in accordance with the size of the suction tubes 1 or of individual components of the suction tubes 1 and the manner in which the solution tubes 1 are to be installed and removed. If required, appropriate devices may be installed in the slits 5 and the suction tubes 1 may be provided with appropriate installation bearings, such that it is possible to carry out repair and maintenance work of the suction tubes and associated devices directly in the slits.It may be seen from the Figure that when the vessel is empty the raised suction tubes 1 each lie in the respective slit 5 above the water level which is indicated diagrammatically on the left and right of the ship.

Devices for discharging the dredged material loaded into the hopper 4 of the vessel are provided and can be located in the hopper 4. For example, bottom flaps 12 may be provided. By installing a suction-extractor system 13, it is also possible to extract dredged material by suction from the hopper 4, the system 1 3 rendering the dredged material free-flowing.

As can be seen from Figure 2, the end of each suction tube 1 is connected to a respective feed pump 3 for ensuring the conveying capacity of the tube 1. Next to the shafts 8 with the hatch covers 9, it is possible to see in the hopper, in Figure 2, overflow devices 11 which convey overflowing material from the hopper into the slits 5.

The dredged material is fed through one or more conveying lines 10 connected to each suction tube 1 into the hopper 4 of the hopper suction dredger.

Each slit 5 has at least at one end shaped portions, not shown in any more detail in the drawings, which wash out material circulating in the water, for example ice floes. For this purpose, the stern lateral limiting line of the slits 5 can end in a slope, so that the circulating material is conveyed out of the slits by the water of the waterway.

Figure 3 shows a plan view of a section taken along the line A-A of Figure 1. One suction tube 1 with its suction head 2 and its associated feed pump 3 can be seen in the lower portion of Figure 3.

The conveying lines 10 connected to the suction tubes 1 are also illustrated. Winches 6 located in the empty cell 7 may be seen through open shafts 8 in the upper portion of Figure 3. The overflow device 11 in the hopper 4 of the vessel is also illustrated in its position in relation to the centre line of the ship.

The above-described connection by means of which overflow material passes from the hopper into the slits 5 has the advantage that as a result of the higher temperature of the overflowing dredged material the slits 5 are prevented from s being covered with ice.

Claims

1. A hopper suction dredger characterised in that in the ship's hull one or more slits are provided for receiving one or more suction tubes, the or each said slit being open at the bottom.

2. A dredger as claimed in Claim 1, characterised in that a single slit is located in the region of the longitudinal centre plane of the ship.

3. A dredger as claimed in Claim 1, characterised in that several slits are provided and are located symmetrically of the longitudinal centre plane of the ship's hull.

4. A dredger as claimed in any of Claims 1 to 3 characterised in that winches are located above the or each slit for lowering and lifting the suction tube or tubes.

5. A dredger as claimed in Claim 4, characterised in that the winches are located in empty cells above each slit.

6. A dredger as claimed in Claim 5, characterised in that shafts are provided as access to the empty cells.

7. A dredger as claimed in Claim 6, characterised in that the shafts can be closed by means of hatch covers.

8. A dredger as claimed in any preceding claim, characterised in that a conveying line for feeding the suction material into the hopper is connected to the or each suction tube.

9. A dredger as claimed in any preceding claim, characterised in that the or each slit is connected to one or more overflow devices in the hopper.

10. A dredger as claimed in any preceding claim, characterised in that the or each slit has at least at one end shaped portions which wash out material circulating in the water.

11. A dredger as claimed in any preceding claim, characterised in that at least one limiting wall of the or each slit is inclined.

12. A dredger substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.