EP1040997A1

EP1040997A1 - Device for balancing a vessel

Info

Publication number: EP1040997A1
Application number: EP00201160A
Authority: EP
Inventors: Johannes Ravestein
Original assignee: Ravestein Container Pontoon BV
Current assignee: Ravestein Container Pontoon BV
Priority date: 1999-04-02
Filing date: 2000-04-01
Publication date: 2000-10-04
Also published as: NL1011728C2

Abstract

The invention relates to a device (14) for balancing a vessel (13), characterized in that the device (14) is provided with: at least one body (1) with a certain mass, which body is movable substantially in transverse direction of the vessel; drive means (6) for moving the body; measuring means (12) for measuring the angle of inclination of the vessel relative to the horizon; and control means (15) for operating the drive means at a first value of the angle of inclination measured by the measuring means, which first values does not equal zero, for moving the body to a position of balance in which the angle of inclination has a second value which is preferably substantially equal to zero.

The invention also relates to a vessel, such as a container ship, provided with such a device.

Description

The present invention relates to a device for balancing a vessel.
During for instance loading of a vessel with cargo, for instance a canal barge with containers, the problem occurs in practice that the vessel heels over to the more heavily loaded side. Further loading of the vessel can then only continue after the vessel has been balanced again. This balancing takes place by pumping ballast water over to ballast tanks specially present for this purpose. The drawback to this solution is that very large pumps are required in order to be able to carry out the balancing at a speed which is in any way acceptable.
The invention has for its object to provide a device of the above stated type which does not have this drawback.
The device according to the invention has for this purpose the feature that the device is provided with: at least one body with a certain mass, which body is movable substantially in transverse direction of the vessel; drive means for moving the body; measuring means for measuring the angle of inclination of the vessel; and control means for operating the drive means at a first value of the angle of inclination measured by the measuring means, which first value does not equal zero, for moving the body to a position of balance in which the angle of inclination has a second value which is preferably substantially equal to zero.
In a first preferred embodiment the material of the body consists substantially of a solid material with a high specific weight. An example of a suitable material is steel because it can be readily processed and has a low cost.
In a compact preferred embodiment the body has a generally rectangular form.
In a further practical preferred embodiment the body is mounted on guides. A first set of guides is preferably arranged on either side of the body for co-action with a second set of counter-guides mounted on the vessel. In order to facilitate the movement the guides comprise a material with a low coefficient of friction, for instance plastic such as Teflon.
The drive means preferably take a hydraulic form. One hydraulic cylinder can suffice when it engages substantially on the middle of the body.
The measuring means preferably comprise a commercially available inclinometer.
In an elegant preferred embodiment the control means are adapted to automatically operate the drive means in co-action with the measuring means in order to move the body to the position of balance. This can be realized for instance by means of a PLC control.
In the most compact preferred embodiment the device according to the invention comprises one body.
In an alternative embodiment the device comprises two bodies which are placed at some mutual distance.
The invention also relates to a vessel, such as a container ship, provided with a device according to the invention.
The invention will now be discussed in more detail with reference to the drawings, in which
Figure 1 shows a schematic view of the container ship provided with a device according to the invention; and
Figure 2 shows the device according to the invention of figure 1 in more detail.
Figure 1 shows a container ship 13 which is provided with a device 14 according to the invention. Container ship 13 is of a narrow type which provides space for two mutually adjacent rows of containers. Because of the narrow width this ship is eminently suitable for inland navigation, since the ship can also navigate smaller rivers without problem. The small width does however result in the problem that after loading of a container on one side the ship will heel over to this side. The angle of inclination will in many cases be such (for instance 5 to 6 degrees) that the ship will first have to be balanced by means of device 14 before a subsequent container can be loaded.
Device 14 comprises a solid body 1 with a generally rectangular form. The material of the body is preferably a solid material with a high specific weight. Suitable examples are steel, lead and many comparable materials known to a skilled person in the field. Alloys of materials with a sufficiently high specific weight can also be used. In addition, it is conceivable to apply as alternative a holder filled with a liquid.
Figure 2 shows device 14 in more detail. Body 1 is movably mounted on guide rails 2 and 3. A pair of guides 2 is mounted on either side of body 1 and co-acts with a pair of counter-guides 3 fixed to vessel 13. A layer 4 of plastic with a low coefficient of friction is applied to the contact surfaces of one or more of the guides. Examples of suitable plastics are Teflon and Hakorit. An additional guide 5 for body 1 is arranged on the bottom of vessel 13. The orientation of device 14 is such that body 1 is movable substantially in transverse direction of vessel 13.
The drive for body 1 preferably takes a hydraulic form and comprises a hydraulic circuit incorporating therein a hydraulic pump 9, a tank 7 with hydraulic fluid, valves 11, conduits 10 and a hydraulic cylinder 6. An electric motor 8 drives hydraulic pump 9.
Cylinder 6 engages body 1 in the centre and can carry the body to any desired position on the guide rails by means of a continuous movement.
Measuring means 12, for instance a commercially available inclinometer, co-act with control means 15, for instance a PLC control, to operate the drive means.
The operation of device 14 is as follows. As soon as, for instance during loading, an inclination of vessel 13 to port or starboard with an associated angle of inclination of a magnitude of minimally a first value is measured using inclinometer 12, PLC control 15 drives body 1 in opposite direction until body 1 has reached the position of balance, i.e. the position in which the angle of inclination has a second value which is preferably such that the angular displacement is sufficiently neutralized to enable further loading. In this preferred embodiment the balancing takes place fully automatically on the basis of a feedback principle, i.e. the position of body 1 is adjusted by the drive means under the influence of the control means until the inclinometer finally indicates that the desired second value of the angle of inclination has been reached. It is noted, perhaps unnecessarily, that in the context of this application the term "angle of inclination" is understood to have the meaning of this term as known in the relevant field, i.e. the angle the vessel makes with the horizon.
The control means are preferably adapted such that the first and second value are adjustable. The first value is greater than zero, for instance a few degrees, and the second value is substantially equal to zero. Some tolerance in these values, for instance of half a degree, is permitted in practice.
Alternatively, it is also conceivable for the control means to be adapted to operate the drive means after receiving an external command in order to move the body to the position of balance. Such a command can for instance be entered by means of manual operation. This is possible for instance after the inclinometer has generated a warning signal that the angular displacement of the vessel has taken on too large a value.
In the shown embodiment body 1 is arranged in the stern of vessel 13. In an alternative embodiment (not shown) device 14 can comprise two bodies, one of which is arranged for instance in the front of the vessel and one in the rear of the vessel. The embodiment of each of these bodies can be the same as the above described embodiment of body 1.
The weight of body 1 is adapted to the type of vessel and the weight of the cargo to be loaded thereon. In the described application on a container ship with cargo space for two mutually adjacent rows of containers of for instance 24 tons each, the expectation is that a weight of 12 tons will be eminently satisfactory. In a larger container ship providing space to more rows of containers of for instance 32 tons each placed mutually adjacently, a body with a larger weight is required. In the embodiment with two bodies the weight is preferably distributed equally over both bodies, although this is not essential. It is noted that practical use can be made of the lever principle to reduce the weight of body 1 by choosing a longer length of the guides. If required, the length of the guides can be so long that the body extends beyond the containers as seen in transverse direction of the vessel.
The invention is of course not limited to the described or shown embodiment(s). It is particularly noted that the invention can also be applied in vessels other than container ships. In a general sense the invention is applicable in all floating objects suitable therefor which have to be balanced, including for instance pontoons. The device according to the invention can further serve as assist means in a variety of other situations in addition to that of loading. The invention therefore generally extends to any embodiment which falls within the scope of the appended claims as seen in light of the foregoing description and drawings.

Claims

Device for balancing a vessel, characterized in that the device is provided with:

at least one body with a certain mass, which body is movable substantially in transverse direction of the vessel;

drive means for moving the body;

measuring means for measuring the angle of inclination of the vessel; and

control means for operating the drive means at a first value of the angle of inclination measured by the measuring means, which first value does not equal zero, for moving the body to a position of balance in which the angle of inclination has a second value which is preferably substantially equal to zero.
Device as claimed in claim 1, wherein the material of the body consists substantially of a solid material with a high specific weight.
Device as claimed in claim 2, wherein the material is steel.
Device as claimed in claim 1, 2 or 3, wherein the body has a generally rectangular form.
Device as claimed in any of the foregoing claims, wherein the body is mounted on guides.
Device as claimed in claim 5, wherein a first set of guides is arranged on either side of the body for co-action with a second set of counter-guides mounted on the vessel.
Device as claimed in claim 5 or 6, wherein the guides comprise a material with a low coefficient of friction, for instance plastic such as Teflon.
Device as claimed in any of the foregoing claims, wherein the drive means take a hydraulic form and comprise at least one hydraulic cylinder.
Device as claimed in claim 8, wherein the cylinder engages substantially on the middle of the body.
Device as claimed in any of the foregoing claims, wherein the measuring means comprise an inclinometer.
Device as claimed in any of the foregoing claims, wherein the control means are adapted to automatically operate the drive means in co-action with the measuring means in order to move the body to the position of balance.
Device as claimed in claim 11, wherein the control means comprise a PLC control.
Device as claimed in any of the foregoing claims, wherein the device comprises one body.
Device as claimed in any of the foregoing claims 1-13, wherein the device comprises two bodies which are placed at some mutual distance.
Vessel, such as a container ship, provided with a device as claimed in any of the foregoing claims.