EP0126395B1 - Method and device for stowing goods which can be destroyed by condensed water - Google Patents

Abstract

Bulk cargo which is sensitive to condensate is confined in the cargo area of a seagoing or other vessel in such a way that it comes into direct contact with the walls surrounding the cargo area and is also in contact with moisture-laden air filling the remainder of such area. In order to prevent condensation of moisture on the walls surrounding the cargo area, the temperature of the walls as well as the temperature of air in the cargo area is maintained at a value such that the moisture cannot condense on the walls. This can be achieved by heating the confined air and/or the walls and/or by reducing the moisture content of confined air and/or by a combination of such undertakings.

Description

The invention relates to a method for stowing a condensation-prone good in a hold of a ship, in the interior of which air of determinable moisture and temperature is enclosed, which comes into contact with walls on which condensation can take place and in which the walls reach a temperature level at least in some areas be heated, on which a condensation of moisture on the walls is prevented.

This method is intended to prevent heat flow from cooled parts of a cargo space by heating intermediate walls in the area of this heat flow. For this purpose, heaters are attached to the partition walls. With the help of this heater, a heat flow is generated in the area of the walls arranged between the cooled cargo holds. This heat flow compensates for the heat flow from the walls adjacent to the cooled cargo holds and prevents condensation of moisture in the area of the wall transitions.

With the help of these heaters, however, the problem of condensation water during the transport of bulk goods cannot be solved. When transporting such bulk goods, no inner walls or intermediate floors dividing the cargo space of the ship are provided. Rather, the bulk goods are poured directly into the cargo space delimited by the outer walls, the floor and the cargo area cover. The arrangement of heating elements in the area of certain cold bridges is therefore not sufficient to prevent condensation in the hold. Rather, condensation will form on the walls of the cargo holds, particularly when the ship is traveling from warm areas in which it has been loaded to cold areas, where the cargo area walls cool to a temperature at which the moisture contained in the warm air cools down on the cold walls of the cargo hold. This condensation leads to large-scale sweat water formation.

It is therefore an object of the present invention to improve the method of the type mentioned in the introduction in such a way that goods which are susceptible to condensation can also be transported in bulk. This object is achieved in that the walls are heated in the area of their entire extent facing the goods in the area of their limits facing away from the goods to a temperature level preventing the condensation of moisture, a heat flow from the wann 'engineers towards the interior of the cargo space is generated and both the temperatures of the ambient air washing around the cargo and the temperatures of the walls are controlled to prevent condensation of moisture in the entire area of the cargo area.

These process steps can reliably prevent moisture condensation in the entire area of the cargo hold. Condensation of the moisture is prevented not only on the load compartment walls but also in the area of the entire load space and in particular on the load itself. The parts of the load compartment wall occupied by the cargo are particularly prone to the formation of condensation water since they cannot be adequately ventilated. However, due to the heat introduced into the cargo area over a large area, these parts of the walls also have a temperature level at which moisture condensation is excluded. This prevents rotting nests from forming directly in the area of the stored goods due to moisture. Rather, it arrives at the destination completely dry and without rotting nests.

In addition, a ship is known with at least one hold, inside of which a condensation-prone good is stowed and air of determinable moisture and temperature is enclosed, which comes into contact with walls on which condensation can take place.

Such ships are not suitable for transporting moisture-sensitive goods in bulk. Condensation forms on the walls of the holds, particularly in the area of the stowed goods. The stagnant material comes into contact with this condensation water and forms putrefaction nests, which can take possession of the entire stowed goods the faster, the better the preconditions for the formation and growth of putrefaction nests. In particular in warmed cargo holds, which have become known, for example, from GB-A 67 52 84, the putrefaction nests spread over the entire cargo at high speed.

In a similar way, the process known from French patent 919.123 does not prevent the formation of putrefaction nests and their expansion to the entire load, but favors them to a considerable extent. In this process, too, heated air is passed through the hold. It is first passed between an inner wall delimiting the cargo space and an outer wall delimiting the ship and can then enter the cargo space through openings provided in the inner wall. The walls of the loading space are insulated on their outside facing away from the goods, so that heat cannot be transferred through the walls into the loading area or only with difficulty. This prevents the cargo space walls in the area of the goods from reaching a temperature that prevents the goods from rotting to take. In the area of the property, putrefaction nests develop, the formation and enlargement of which is promoted by the warm air introduced into the cargo hold.

A ship has become known from British Patent Specification 18 848, which has a cargo space enclosed by an inner wall. There is an intermediate space between the inner wall surrounding the cargo space and an outer wall delimiting the ship, into which air conditioning air is introduced. Depending on the area of application of the ship, it can be ensured with the aid of the appropriately tempered air that a desired climate is generated in the hold. However, no consideration has been given to heating the cargo space walls to a temperature which is sufficient to allow a heat flow to pass through the cargo space walls and which is dimensioned sufficiently large to prevent condensation of the air in the cargo space . Rather, condensation phenomena appear on the cargo space walls, which are particularly pronounced in the area of the cargo and lead to a spoilage of the stowed goods there.

The object of the present invention is therefore to improve the ship of the type mentioned in the introduction in such a way that condensation-sensitive goods can be stowed in its hold without fear of damage to the goods by condensation water.

This object is achieved in that the walls laterally delimiting the cargo space; the floor delimiting the cargo space in the ship's vertical axis at the bottom and a cargo space cover lying opposite the floor are at least partially formed as heated double-walled heat exchangers that heat the cargo space and have at least one interior through which a heating medium flows and with at least one the temperature of both the air and the walls are connected to a control device which keeps the condensation of moisture at a level.

Such a ship is particularly suitable as a bulk carrier for the transport of bulk water-sensitive bulk goods. Until now, goods sensitive to condensation had to be packed in special packaging units, which in turn were stowed in the hold of a general cargo ship. For example, coffee could not be transported in bulk, although transportation costs make up a significant portion of the cost of coffee. Now, for example, coffee can also be stowed in bulk in the holds of a bulk carrier, without the risk of condensation forming in the area of the goods lying against the walls. In addition, the condensation-prone goods can also be packed in large units, such as containers, in the holds. The containers standing in the appropriately tempered cargo holds have a temperature on their outer sides as well as on their inner walls facing the stowed goods that is sufficient to prevent the formation of condensation. The transportation of coffee in bulk saves considerable transportation costs.

Further details of the invention will become apparent from the following detailed description and the accompanying drawings, in which a preferred embodiment of the invention is illustrated, for example.

• Fig. 1 Einen Querschnitt durch einen Schiffskörper mit einem erfindungsgemäßen Laderaum,
• Fig. 2 einen Schnitt durch einen Laderaum entlang der Linie 11-11 in Fig. 1.

The drawings show:

• 1 shows a cross section through a hull with a hold according to the invention,
• FIG. 2 shows a section through a loading space along the line 11-11 in FIG. 1.

A ship consists of a hull 1, which has at least one cargo space 2. This cargo space 2 is enclosed on all sides by walls 3. The walls 3 consist of a floor 4, two side walls 5, 6 extending in the longitudinal direction of the ship, two transverse walls 7, 8 extending in the transverse direction of the ship and a cover 9 which closes the cargo space 2 on its side facing away from the floor 4 and is designed as a hatch cover.

The hull 1 is designed with two shells, so that outer walls 10, 11, 12 extend parallel to the side walls 5, 6 and the bottom 4, between which and the side walls 5, 6 and the bottom 4 cavities 13, 14, 15 are formed are.

The cover 9 is also double-shelled and has an outer wall 16 running parallel to it, which together with it encloses a cavity 17. The transverse walls 7, 8 likewise have outer walls 18, 19 running parallel to them on their sides facing away from the loading space, which together enclose cavities 20, 21 with them.

All cavities 13, 14, 15, 17, 20, 21 each extend on the side 28 of a wall 3 facing away from the loading space 2 over its entire surface area. The cavities 13, 14, 15, 17, 20, 21 are each connected to at least one adjacent cavity 13, 14, 15, 17, 20, 21 via connections 22. The cavities 13, 14, 15, 17, 20, 21 are flowed through by a heating medium used as a heating medium, which preferably consists of warm water. Cooling water can be used as water, which has been heated by a ship's engine 32 and is distributed evenly over the cavities 13, 14, 15, 17, 20, 21 via feed lines 33 and from there is led back to the ship's engine via leads 34. On at least one connection 22 between two cavities 13, 14, 15, 17, 20, 21 at least one circulation pump 23 is provided, with the aid of which the hot water located in the cavities 13, 14, 15, 17, 20, 21 is constantly in motion is held and is exchanged between the individual cavities 13, 14, 15, 17, 20, 21 in order to avoid temperature differences on the walls 3. The circulation pump 23 and the hot water supply is from. controlled by a thermostat control 31, which has temperature sensors 29, 30 in the hold 2 and via which the supply and circulation of the warm water is controlled in such a way that the temperature of the air in the hold 2 is kept constant during the entire transport.

Loads that are susceptible to condensation are filled into loading space 2 in a loading port. At the same time, the ambient air in the loading port penetrates into the cargo hold 2. It is of relatively high temperature and humidity, especially in overseas ports. In addition, the charge also has a relatively high temperature. It is filled into the loading space 2 as bulk material.

After the cargo space. 2 has been filled, the loading space cover 9 designed as a hatch cover is closed. Then the ship can sail. On the northern route, the ship will reach sea areas where both the air and water temperatures are significantly lower than those in the loading port. In particular, the outer walls 10, 11, 12 of the ship cool down considerably. The air contained in the cargo space 2 comes into contact with the outer walls 10, 11, 12, cools down there greatly, so that it approaches the condensation point of the liquid dissolved in it. In order to prevent the condensation of moisture, the heat medium is moved through the cavities 13, 14, 15, 17, 20, 21 with the help of the circulation pumps 23. The heat medium has the temperature of the air enclosed in the cargo space 2, so that it cannot cool down on the walls 3. It is able to keep the moisture it contains dissolved without showing any signs of condensation at any point.

In order to keep the temperature at the predetermined level, the termostats scan the temperature on the walls 3. The measurement results are entered into the termostat control 31. This controls the circulating pump 23, with the aid of which a quantity of cooling water corresponding to the respective temperature conditions is pumped, which leaves the ship's engine at the outlet 35 in the hot state and re-enters the ship's machine 32 via the derivatives 34 at an inlet 36.

It is also possible not to directly pump the cooling water through the cavities 13, 14, 15, 17, 20, 21 through the circulation pump 23. Rather, a heat exchanger through which the cooling water flows can be arranged between the outlet 35 and the inlet 36 of the ship's engine 32, which heat exchanger is not shown in the example. Within this heat exchanger, the heat medium is heated to the extent that it is able to keep both the walls 3 and the interior of the cargo space 2 at a temperature at which condensation of the moisture dissolved in the air is avoided.

The heat can be dissipated from the walls 3 directly into the interior of the hold 2. However, it is also possible to set up heating units through which the heat medium flows in the interior of the loading space 2 and which emit the heat directly to the load and to the air surrounding it. Finally, it is conceivable that 2 longitudinal bulkheads 37 and transverse bulkheads 38 extend in the interior of the loading space, which are connected to the cavities 13, 14, 15, 21 via connections 22. These longitudinal bulkheads 37 and transverse bulkheads 38 can also give off heat to the interior of the loading space 2.

In addition, it is also conceivable to install a measuring sensor 39 in the interior of the cargo space 2, which is suitable for measuring the humidity of the air enclosed in the cargo space 2. This sensor 39 is connected to a computer 41 via a measuring line 40. At the same time, control pulses from the termostat control 31 are fed into the computer 41 via a further line 42. This computer 41 has a program that can be used to calculate the condensation point of moisture in the. air trapped in the hold 2 is released. According to the moisture value determined by the computer 41, the thermostat control 31 is controlled to a temperature level at which the condensation of the moisture in the cargo space 2 is just being avoided. In this way, it is conceivable to lower the temperature in the loading space 2 to a level which is below the temperature level at which the air which has entered the loading space 2 in the loading port is located. However, the temperature in the hold 2 can only be reduced to such an extent that the formation of condensation water, in particular in the region of the walls 3, is reliably avoided. In order to have the necessary security to this extent, several sensors 39 can be distributed in the cargo space 2 and on the walls 3.

Finally, it is conceivable to lower the humidity of the air enclosed in the hold 2. The drier the air, the further the temperature in the hold 2 can be lowered. The air can be dried using dehumidifiers. For this purpose, the moist air is sucked out of the hold 2 and fed back to the hold 2 in the dried state.

When the air is heated, care must be taken to ensure that the temperature level in the entire cargo hold 2 does not fall below the condensation point. Since the heat is introduced from the walls 3 into the cargo space 2, it is conceivable that the temperature in the interior of the cargo space 2 is lower than at the walls 3. This possibility is all the more given that the charge forms a poor heat conductor. In particular, to take into account that the air outside the cargo in the hold 2 is a poor heat conductor. The worse the charge and the air conduct the heat, the higher the walls 3 have to be heated. The longitudinal bulkheads 37 and transverse bulkheads 38 also ensure a uniform distribution of the heat.

In order to avoid excessive heat radiation to the outboard during transport, all outer walls 10, 11, 12, 16, 18, 19 are provided with insulation 24, each of which extends over the entire surfaces of the outer walls 10, 11, 12, 16, 18, 19 each extend on the sides facing the cavities 13, 14, 15, 17, 20, 21. In addition, ribs 43 or other measures improving the heat transfer can be provided in the cavities 13, 14, 15, 17, 20, 21. Good heat transfer from the heat medium flowing through the cavities 13, 14, 15, 17, 20, 21 to the walls 3 takes place at these ribs 43. In addition, it is conceivable to provide similar measures within the cargo space 2. However, since such measures may make stowage and unloading of the cargo more difficult, in most cases such measures will probably be avoided within the cargo space 2. Since slight differences in temperature between the walls cannot be avoided, the fan 25, which is expediently provided in the area of the hatch cover 9, ensures that the most ideal possible temperature compensation takes place. For this purpose, it keeps the air trapped in the hold 2 in motion and in this way avoids the formation of condensation.

The loading space cover 9, which is designed as a double-shell hatch cover, has, in the area of its connections 22 with an adjacent cavity 13, 20, 21 attachment points 26 at which the connections 22 are detachably attached, so that the hatch cover can be removed for loading and unloading. At the attachment points 26 of the loading space cover 9, closure members 27 are preferably provided, with which the attachment points 26 on the loading space cover 9 can be closed so that the water contained in the cavity 17 does not flow out. However, this water can be drained off before the loading space cover 9 is removed in order to reduce its weight.

It is also possible not to heat the walls 3 through hollow spaces filled with hot water running parallel to them, but to guide heating coils along the walls 3 along the sides facing away from the loading space 2. Warm water can also flow through the heating coils.

In the event that the waste heat output of the marine engine is not sufficient to provide enough hot water for heating a cargo hold 2, a further hot water source can be provided. It is also possible to provide electrical heating instead of hot water heating, for example in the form of heating elements which extend uniformly over the walls 3 on their sides facing away from the loading space 2.

Claims (17)

1. A method of stowing material which is endangered by sweating in a hold (2) in a ship, in the interior of which is enclosed air of determinable humidity content and temperature, which comes into contact with walls (3) at which condensation can occur, and in which the walls (3) are heated at least in a region-wise manner to a temperature level at which condensation of moisture on the walls is prevented, characterised in that the walls (3) are heated to a temperature level for preventing the condensation of moisture, in the region of their entire extent which is towards the material, in the region of their boundaries which are remote from the material, a flow of beat from the walls (3) towards the interior of the hold (2) is produced and both the temperatures of the ambient air flowing around the material and also the temperatures of the walls (3) are regulated to prevent condensation of moisture in the entire region of the hold (2).

2. A method according to claim 1 characterised in that the humidity of the air is regulated to a level at which condensation of the moisture on the walls (3) is prevented.

3. A method according to claim 1 or claim 2 characterised in that the humidity and temperature of the volume of air are measured, the condensation point thereof is calculated and the volume of air and the walls (3) are held at a temperature which is above the condensation point.

4. A method according to one of claims 1 to 3 characterised in that moisture is removed from the volume of air.

5. A method according to one of claims 1 to 4 characterised in that on their boundaries which are remote from the material the walls (3) are heated by a beat carrier which is kept above a condensation temperature and the circulation of which is controlled in dependence on the temperatures of the air and the walls (3), as measured in the hold (2).

6. A method according to one of claims 1 to 5 characterised in that the temperature of a gas which is used as a beat carrier is regulated to a level which prevents condensation of the moisture.

7. A ship comprising at least one hold (2), in the interior of which is enclosed air of determinable humidity and temperature, which comes into contact with walls (3) at which condensation can occur, characterised in that the side walls (5, 6) which laterally define the hold (2), the floor (4) which defines the hold (2) at the bottom on the vertical axis of the ship and a cover (9) which is disposed in opposite relationship to the floor (4) are at least in a region-wise manner in the form of heated, double-walled heat exchangers which beat the hold (2) and which have at least one internal space through which flows a heating medium, and which are connected to at least one regulating means which holds the temperature both of the air and of the wall (3) at a level which prevents the condensation of moisture.

8. A ship according to claim 7 characterised in that there is provided a control means for influencing the humidity in the air.

9. A ship according to one of claims 7 and 8 characterised in that the walls (3) are in the form of heat exchangers.

10. A ship according to one of claims 7 to 9 characterised in that the hold cover (9) is in the form of a hatch cover through which the beat carrier flows.

11. A ship according to one of claims 7 to 10 characterised in that at least the walls (3) are in the form of a double shell through which the beat carrier flows.

12. A ship according to claim 11 characterised in that the double shell has installations (43) for promoting the transfer of beat, in its hollow space (13, 14, 15, 17, 20, 21) through which the beat carrier flows.

13. A ship according to one of claims 11 and 12 characterised in that provided in the hollow space (13, 14, 15, 17, 20, 21) of the double shell is an insulation (24) which is fixed on an outside shell of the double shell, which is remote from the hold (2).

14. A ship according to one of claims 7 to 13 characterised in that there is provided a heat exchanger which is fed on the primary side by the cooling water of the ship's engine (32) and on the secondary side by a medium which is to be used as a heat carrier.

15. A ship according to claim 14 characterised in that a gas is provided as the medium.

16. A ship according to one of claims 7 to 15 characterised in that provided in the hold (2) is a . fan (25) for circulating the air contained in the hold (2).

17. A ship according to one of claims 7 to 16 characterised in that communications (22) for the heat carrier to flow therethrough are provided between the double shells.

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