JP5557917B2 - How to prepare a dry bulk carrier - Google Patents

Description

  The present invention relates to a method for preparing a dry bulk carrier. More specifically, it relates to a method for preparing a dry bulk carrier for transporting sand and fluidized loading and unloading.

  Large amounts of material are often required when reclaiming sea areas to obtain land. According to the prior art, so-called self-loading dredgers TSHD (“stern suction hopper dredger”) are usually used. During transport from the loading site to the loading / unloading site, the material is placed in a silo-like compartment in the hull. The material can be unloaded by opening the bottom of the hull, for example by a hull formed in two parts configured to be able to be moved relative to each other.

  EP 0 767 618 discloses a hull having a bottom hatch.

European Patent No. 0767618 U.S. Pat. No. 3,445,008 U.S. Pat. No. 4,033,470

  However, the types of hulls mentioned are not particularly suitable for carrying large quantities of material over long distances, especially transport in open sea areas. This reason is related to economy, considering that these hulls are relatively expensive to build and operate, and because of their relatively limited carrying capacity.

  It is known to fluidize material prior to and during unloading. To that end, U.S. Pat. No. 3,445,008 describes a method and apparatus in which the lower part of the hull hold is filled with water before pumping out water and material.

  From US Pat. No. 4,033,470 it is known to fluidize a load using a nozzle and pressurized water.

  Transport of material within the hold generally requires that the hold be closed and that the cargo must be classified as dry during transport in the open sea.

  The use of a dry bulk carrier to carry dredged material has been proposed, and patent application No. 19989861 describes a loading and unloading device to be placed on the surface of the load, which flows the load. It is configured to enable it to be pumped and discharged by a pump. However, the loading and unloading capacity of such solutions has proven to be inadequate.

  The object of the present invention is to eliminate or reduce at least one of the disadvantages of the prior art.

  According to the invention, the object is achieved by the features disclosed in the following description and the subsequent claims.

  A method is provided for preparing a dry bulk carrier for the transport and unloading of sand, which comprises a fluidizing pipe having an inlet opening and also a fluidized sand inside a multipurpose hold. Disposing a slurry inlet for the method, and the method further includes disposing a slurry pump connected between the slurry inlet and the unloading pipe, the slurry pump being a multipurpose hold. It is placed in the hold next to.

  The method can further include placing a slurry inlet in the bulkhead between the holds. Thus, the slurry can be unloaded from the multipurpose hold of a dry bulk carrier without having to substantially change the hull layout.

  The method may further include the step of positioning a water pump to be connected between the water inlet and the fluidizing pipe in the hold adjacent to the multipurpose hold.

  By placing the pump in the adjacent hold, the pump is placed at a level near the floor of the multipurpose hold. At the same time, the slurry pump can be placed near the slurry inlet. This reduces cavitation that would otherwise occur at a substantial degree in the pump. Slurry outflow to the slurry pump is facilitated by static pressure from the sand that is placed on top of the slurry in the multipurpose hold and generates pressure in the slurry.

  During loading and unloading, water can flow from the water inlet through an inflow opening that can consist of nozzles to fluidize sand that is placed closest to the multipurpose hold floor, often referred to as the tank top. To do. If desired, fluidized pipes with inflow openings can also be placed on the walls of the multipurpose hold or at different levels of height in the multipurpose hold.

  In order to further improve sand fluidization, the method may also further comprise the step of placing an air injection pipe in the multipurpose hold, preferably near its floor. The air injection pipe may be provided with an air injection opening such as a nozzle. The air injection pipe is connected to the compressor, typically via a pressure tank. Experiments demonstrate that water fluidized sand obtains better fluidity by mixing some air into the fluidized sand.

  If a dry bulk carrier exceeds the capacity of the dry bulk carrier, not all cargo holds are filled with sand. For this reason, it is also appropriate to use, for example, all other holds for technical installations that can include valves and control components in addition to pumps and potential compressors. In order to adjust the specific gravity of the fluidized sand before entering the slurry pump, a water injection pipe to the slurry pipe can also be arranged on the inflow side of the slurry pump. Water can be supplied from a water pump or from a hull seawater box.

  In general, equipment in one hold can operate on two adjacent holds

  The fluidized material can be unloaded by allowing it to flow upward into the slurry inlet via a slurry pump and unloading pipe.

  The method further comprises the step of allowing the unloading pipe to terminate outside the dry bulk carrier when the sand is to be unloaded from the dry bulk carrier, or the fluidized sand is dry bulk. The step of connecting the unloading pipe to the transport pipe at a location remote from the cargo ship, for example when it is to be delivered to the shore, may be included.

  Ships for transporting sand are usually loaded with fluidized or very wet sand, typically excavated from the seabed near the loading site. This sand must be drained in order to be classified as dry during transport.

  The method may further include the step of placing at least one drainage column in the multipurpose hold for sand drainage. This type of drainage column can consist of pipes with a number of openings in the pipe wall along the pipes, each opening being provided with a screen to allow water to enter through the openings, and sedimented sand. Covers the screen and prevents a significant amount of sand from entering the drainage column through the opening.

  The method may also further include connecting a drain column to the slurry pump to pump water from the sand surface.

  The use of a dry bulk carrier, preferably having at least three holds and prepared in accordance with the present invention, for transportation through the open sea is a substantial time and cost for sand transport and unloading. Allows reduction.

  According to the present invention, at least one of the disadvantages of the prior art can be eliminated or reduced.

An example of a preferred method and embodiment is described below and is depicted in the accompanying drawings.
1 shows in cross section a dry bulk carrier according to the invention during loading. FIG. It is a figure which shows the top view of the division of the hold of a dry bulk carrier. It is a figure which shows the detail of the multipurpose hold of a dry bulk carrier in the perspective view, and the range of the multipurpose hold is shown by the broken line. It is a figure which shows the cross section which passes along a drainage column with a big scale.

  In the drawings, reference numeral 1 denotes a dry bulk carrier, which comprises several holds 2, at least one of which is used as a multipurpose hold 4.

  In FIG. 1, the dry bulk carrier 1 is fixed next to the fixture 6, and the fluid form of sand flows from the fixture 6 through the filling pipe 8 into the multipurpose hold 4.

  The multipurpose hold 4 of the dry bulk carrier 1 is provided with a number of fluidized pipes 10 having an inflow opening 12 near its floor-tank top-. The fluidizing pipe 10 extends horizontally in the longitudinal direction of the dry bulk carrier 1 and is connected to the manifold 14. Via the first water valve 16, the manifold 14 is connected to a water pump 18 that receives water from the water inlet 20. See FIG. The water inlet 20 may comprise a seawater box (not shown). The water pump 18 is located in the hold 2 adjacent to the multipurpose hold 4 and is designed to allow water to be supplied to the other adjacent multipurpose hold 4 via the second water valve 22. ing. In FIG. 2, the second water valve 22 is hidden under the water pump 18.

  A part of the fluidizing pipe 10 is disposed on the wall 24 of the multipurpose hold 4.

  A number of air injection pipes 26 having air injection openings 28 are arranged near the floor of the multipurpose hold 4. The air injection pipe 26 communicates with a pressure tank 30 placed in the adjacent hold 2 with respect to the multipurpose hold 4.

  A slurry inlet 34 is located in the partition wall 32 between the hold 2 and the multipurpose hold 4. The multipurpose hold 4 is connected to the inlet of the slurry pump 38 via the slurry inlet 34 and the slurry valve 36. The slurry pump 38 is placed in the hold 2 adjacent to the multipurpose hold 4 and connected to the unloading pipe 40. The unloading pipe 40 terminates in the sea next to the dry bulk carrier 1.

  An intermediate pipe 42 is connected between the manifold 14 and the inlet of the slurry pump 38. The purpose is to allow the specific gravity of the fluidized sand to be adjusted by supplying additional water through the intermediate pipe 42 before entering the slurry pump 38.

  Three drainage columns 44 are provided in the multipurpose hold 4. The drainage column 44 is connected to a drainage pipe 46 at a lower portion thereof, and is connected to a slurry pump 38 via a drainage valve 48.

  The drainage column 44 comprises a pipe 50 having a number of openings 52 in the pipe wall along its longitudinal extension. See FIG. A screen 54 with no gap at the top and open at the bottom surrounds the pipe 50 with an opening 52, whereby an annular space 56 is formed between the screen 54 and the pipe 50.

  Water can flow up through the annular space 56 and into the pipe 50 through the opening 52, while the sand that has settled around the screen 54 fills the annular space 56 when the multipurpose hold 4 is filled. Is sealed at the bottom. Excess water 58 located above the sand 60 must therefore exit through the opening 52 above the drain column 44. See FIG.

  During the loading of the dry bulk carrier 1, when the fluidized sand flows into the multipurpose hold 4 via the filling pipe 8, the sand 60 settles in the multipurpose hold 4. The slurry valve 36 is closed and the drain valve 48 is opened. As described above, excess water 58 is drained to the sea via the drain column 44, drain pipe 46, and slurry pump 38 via the unloading pipe 40.

  Before the dry bulk carrier 1 is unloaded, the first water valve 16 is opened, the drain valve 48 is closed, and the slurry valve 36 is opened.

  When the water pump 18 is started, water flows from the water inlet 20 into the sand 60 through the water pump 18, the first water valve 16, the manifold 14, the fluidizing pipe 10, and the inlet opening 12, thereby entering the sand 60. A portion of the sand closest to the opening 12 is fluidized to form a slurry.

  When the slurry pump 38 is started, the fluidized sand flows to the unloading pipe 40 via the slurry inlet 34, the slurry valve 36, and the slurry pump 38.

  If desired, air is supplied from the pressure tank 30 to the fluidized sand via the air injection pipe 26 and the air injection opening 28.

  1 dry bulk carrier, 2 cargo hold, 4 multipurpose hold, 6 fixture, 8 filling pipe, 10 fluidization pipe, 12 inlet, 14 manifold, 16 first water valve, 18 water pump, 20 water inlet, 22 Water valve, 24 Wall, 26 Air injection pipe, 28 Air injection opening, 30 Pressure tank, 32 Bulkhead, 34 Thriller inlet, 36 Thriller valve, 38 Thriller pump, 40 Unloading pipe, 42 Intermediate pipe, 44 Drain column, 46 drain pipe, 48 drain valve, 50 pipe, 52 opening, 54 screen, 56 annular space, 58 excess water, 60 sand.

Claims (8)

A method for preparing a dry bulk carrier (1) for sand transport and fluidized loading and unloading, comprising:
Placing a fluidizing pipe (10) having an inlet opening (12) and also a slurry inlet (34) for fluidized sand inside the multipurpose hold (4);
Further comprising the step of placing a slurry pump (38) connected between the slurry inlet (34) and the unloading pipe (40), wherein the slurry pump (38) is adjacent to the multipurpose hold (4). (2)
The dry bulk carrier (1) further includes the step of disposing a water pump (18) to be connected between a water inlet (20) and the fluidizing pipe (10), the water pump (18 ) To supply water into the multipurpose hold (4) through the fluidization pipe (10) to fluidize the sand ,
The method further comprising the step of positioning the slurry inlet (34) in the partition (32) between the holds (2, 4) .   The method according to claim 1, further comprising the step of placing a fluidizing pipe (10) having an inflow opening (12) in the wall (24) of the multipurpose hold (4).   The method of claim 1, further comprising placing an air injection pipe (26) in the multipurpose hold (4).   The method according to claim 1, further comprising the step of discharging said unloading pipe (40) with said dry bulk carrier (1).   The method of claim 1, further comprising connecting the unloading pipe (40) to a transport pipe.   The method of claim 1, further comprising the step of placing at least one drainage column (44) in the multipurpose hold (4). The method of claim 6 , further comprising connecting the drain column (44) to the slurry pump (38). In a dry bulk carrier (1) that transports sand in the open sea and unloads it into a fluidized state.
A fluidization pipe (10) having an inflow opening (12) disposed within the multipurpose hold (4);
A slurry inlet (34) for fluidized sand disposed in a bulkhead (32) between the multipurpose hold (4) and the hold (2) adjacent to the hold (4) ;
A slurry pump (38) connected between the slurry inlet (34) and the unloading pipe (40), the slurry pump (38 being placed in the hold (2) adjacent to the multipurpose hold (4). )When,
A water pump (18) disposed between the water inlet (20) and the fluidizing pipe (10), disposed on the dry bulk carrier (1);
Have
A dry bulk carrier (1) characterized in that water is supplied into the multipurpose hold (4) through the fluidizing pipe (10) to fluidize sand by the operation of the water pump (18). .

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