The present invention relates to a vessel having a double bottom in which one or more heat exchangers are disposed.

The present invention further relates to a heat exchanger, in particular a cooler, suitable for use in the aforesaid vessel, and to a cooling water system comprising such heat exchangers.

Such a heat exchanger and a vessel provided therewith are generally known. It is in particular known to provide the vessel with a specially made so-called "sea box", in which the heat exchanger(s) is (are) disposed. Sea boxes are usually provided on one or more sides, for example in a bulge at the front side or, for example, on the side of the vessel. Furthermore, vessels of this kind having a double-walled hull are known, in the side wall of which hull passages for ballast water are provided for filling the double bottom with outboard water as desired, which outboard water functions as ballast so as to obtain a desired draught and/or stability of the vessel in the absence of cargo.

A drawback is the fact that sea boxes formed on the outer side of the ship's hull mean additional volume, sailing resistance, weight and thus draught and fuel consumption. In addition to that, they take up space which can be usefully used, for example for transporting cargo. Furthermore, inlet openings or passages formed in the side wall of the vessel constitute a risk-increasing mechanical weakening, which is disadvantageous, for example in the case of lateral collisions.

The document US 4360350, which is considered to be the closest prior art, discloses a ship with a propulsion unit cooling line connected with the hollow keel.

The object of the present invention is to provide a vessel comprising a cooling water system and heat exchangers, in which the space taken up in a vessel for the thermal household, and in particular the heat exchangers, is more efficiently utilised and in which the aforesaid drawbacks are eliminated or at least alleviated.

In order to accomplish that object, the vessel according to the invention is characterised in that cooling water passage means are provided in the double bottom, and that heat exchangers connected to said cooling water passage means are disposed in the double bottom, through which heat exchangers a forced flow of cooling water takes place.

The invention is based on the perception that the available space in vessels having a double bottom can at least partially be used for transporting cooling water via passage means to heat exchangers installed between double bottom parts and carrying it outwards again from said heat exchangers. If desired, part of the space between said bottom parts can furthermore be utilised as a storage space for ballast water to be taken in.

In comparison with known vessels comprising cooling water systems accommodated in external sea boxes or in specially created spaces inside the vessel, the invention makes more efficient use of the overall available space in the vessel, which is thus more compact and exhibits a better ratio between useful capacity and total volume.

Another advantage connected with the installation of the heat exchangers in the double bottom and with the forced flow of the cooling water flowing therethrough is that in particular the flow rate and the flow profile of the cooling water are known at all times. Consequently, the arrangement, the geometry and the internal structure of the one or more heat exchangers can be precisely adapted thereto. As a result, the heat exchangers according to the invention are more compact, they do not have any useless overcapacity, they are not overdimensioned and more efficient.

The installation of the heat exchangers possibly at different locations in the double bottom makes the cooling water system according to the invention as a whole less vulnerable to lateral collisions. In addition, the solution as presented herein does not weaken the side walls of the vessel's hull, which enhances safety.

One embodiment of the vessel according to the invention is characterised in that several elongated channels are disposed in or between the double bottom, in which channels the heat exchanger(s) is (are) installed.

By installing the heat exchanger(s) between the double wall parts in the elongated channels which are usually at least latently present, efficient use is made of the available space in the vessel.

Another embodiment of the vessel according to the invention is characterised in that the double bottom and/or the channels are provided with control means for influencing the supply and discharge and/or the distribution of cooling water over the respective channels and heat exchangers.

Apart from the advantage that it is thus possible to influence the intake of cooling water and the distribution thereof over one or more heat exchangers in dependence on, for example, the speed, the cooling water temperature, the required heat exchanging or cooling capacity and the like, it is furthermore advantageous that selective closure of a channel makes it possible to carry out maintenance and repairs on the heat exchanger(s) present therein separately from the other heat exchangers. Moreover, in the case of a possible overcapacity of the overall cooling system, said maintenance can take place while the other each exchangers are normally in use. Maintenance and possible repairs can in that case even take place at sea, during normal operation of the vessel, and the vessel need not be docked - out of use - in order to make this possible. This has a positive effect on the cost of transport.

Furthermore, the vessel according to the invention may comprise this feature that the control means are arranged for operating the heat exchangers in question connected in series and/or in parallel, relative to the course of the cooling water.

This leads to a greater flexibility and a wider choice in the activation and distribution of the available capacity of the various heat exchangers.

Yet another embodiment of the vessel according to the invention is characterised in that the double bottom and/or the channels open into one or more central outboard water inlets, which are each provided with one anti-fouling system to prevent the growth of biological organisms.

Advantageously, only one central anti-fouling system per central water inlet suffices. Such a system confers protection against undesirable growth of so-called bio flora and bio fauna on the entire part of the cooling water system disposed downstream thereof, in which part several heat exchangers will generally be present. Thus it is no longer necessary to use one - generally costly - Anti-Fouling (AF) system for every heat exchanger.

Likewise, it will suffice to use only one anticorrosion system for every central water inlet instead of using one system for every heat exchanger. Heat exchangers not comprising the aforesaid systems are easier to produce.

Other embodiments of the vessel, the cooling water system and the heat exchangers according to the invention are explained in the other dependent claims and will also be elucidated hereinafter, in combination with the associated advantages, with reference to the figures below, in which like elements are indicated by the same numerals. In the figures:

• Figure 1 is a partially cutaway top plan view of the bottom (schematically shown) of a vessel according to the invention;
• Figure 2 is a perspective view of a partially cutaway part of the bottom of the vessel of figure 1, which is provided with channels; and
• Figure 3 is a front view, being the encircled detail of figure 1, showing channels provided with heat exchangers according to the invention, which form part of a cooling water system according to the invention.

Figure 1 shows platings 1 and 2 spaced some distance apart, which form a double bottom 3 of the whole (partially shown) of a vessel 4 (schematically shown). The vessel 4 is provided with one or more heat exchangers 5, which are disposed between the platings 1 a 2 in the double bottom 3, which is present anyhow.

Usually, control means 6, which can be closed or which are adjustable as regard their diameter or width of passage, if desired, are provided in the front plating or the side of the double platings 1, 2, which control means function as inlet and passage means 6 for cooling water, in particular sea water. Furthermore, pipes (not shown in the figure) may form part of the passage means 6, which pipes, like the passage means of the control means 6, extend to the heat exchangers 5 and from there to one or more outlets 7 not formed in the ship's side hull for discharge into the sea. The various control means 6 can for example be controlled by means of generally known processor-controlled means present in a control chamber.

Figures 1, 2 and 3 show an embodiment of the vessel 3 in which several channels 8 extending in the longitudinal direction of the vessel 4 are provided in the double bottom 3, in which channels the heat exchangers 5 are disposed. The elongated channels 8 generally extend parallel to the longitudinal direction of and to the direction of flow along the vessel 4. In this case the front inlets of the channels 8 open into an outboard water inlet 9, which forms a kind of manifold, from where the cooling water taken in via the control means 6 is distributed over the heat exchangers 5 that are in use at that point in time. Further control means 6 (not shown) disposed in the double wall(s) 1, 2 and/or in the partitions 10 therebetween and/or in the channels 8 may be provided for influencing the supply and discharge and/or the distribution of cooling water over the channels 8 and the heat exchangers 5. In this way it is possible to control the serial and/or parallel flow of cooling water between the walls 1, 2, and in particular to and between the channels 8 and to the heat exchangers 5 as desired.

The aforesaid outboard water inlet 9, into which the double wall(s) 1, 2 and/or the channels 8 centrally open, is preferably provided with only one, usually electric, anti-fouling system 11 for controlling or preventing the growth of biological organisms in the form of plant and/or animal life. For example, such a system 11 and/or an anticorrosion system is disposed on the side where cooling water enters a channels 8, which is generally provided with several heat exchangers 5, rather than such systems being mounted on every individual heat exchanger.

To prevent cooling water from flowing around the heat exchanger(s) 5, cooling water blocking plates 12 are provided between the walls of the channels 8 and the heat exchangers 5, the width of which heat exchangers is slightly smaller than the width and the height of the channels 8. The flow through the heat exchanger(s) is thus exactly known, and the purely transverse flow through the heat exchanger(s) that occurs in that case makes it possible to further optimise the mutual distances apart between the pipes installed therein, which transport water to be cooled, and the pattern in which said pipes are arranged in the heat exchanger(s).

Pumps 13 connected to the cooling water passage means 6 and the heat exchangers 5 are provided at various places, which pumps effect a forced flow of cooling water through the respective heat exchangers 5. The pumps 13, which are disposed upstream and/or downstream of the respective heat exchangers 5, stimulate the flow of cooling water through the channels 8 and through the heat exchangers 5. The number of heat exchangers 5 being in operation can be simply geared to the currently required capacity.