• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a device for at least partially compensating the influence of swell or wave action on the speed of an excavating member attached to a vessel, the device comprising: a suction tube for sucking up bottom material, the suction tube being of articulated design in a number of suction tube segments pivotable relative to each other; a draghead provided at the end of the suction pipe which, during use, is dragged along the bottom for loosening and sucking up the bottom material; cables provided between the suction tube and the vessel for supporting individual suction tube segments; at least one lifting element for pivoting suction tube segments relative to each other by lifting or letting at least one of the cables pivot; a control unit for controlling the lifting element, wherein the control unit is adapted to adjust the bottom speed of the excavating member by pivoting suction tube segments. The invention also relates to a method for compensating for such swell or wave action.
    公开号:BE1019231A3
    申请号:E200900228
    申请日:2009-04-10
    公开日:2012-05-08
    发明作者:Albert Cornelis Leendert De Krijger；Johannes Cornelis Goeree；Paul Medard Vercruijsse
    申请人:Ihc Holland Ie Bv；
    IPC主号:
    专利说明:

    DEVICE, SYSTEM AND METHOD FOR INCREASING THE
    Viability
    The present invention relates to a device for at least partially compensating for the impact of swell or wave impact on the speed of an excavating device attached to a vessel, in particular a drag head. The invention also relates to an assembly of a vessel, in particular a trailing suction hopper dredger, and one or more of such devices, and to a method for at least partially compensating for such an influence.
    A trailing suction hopper dredger is a vessel with which material can be extracted from the bottom of a body of water, collected and transported to a suitable destination. The water mass is usually the sea, but trailing suction hopper dredgers can also be applied to a lake or the like. A trailing suction hopper dredger is provided with a long suction pipe coupled to the vessel. The suction tube is suspended from a number of cables which are distributed over the length of the suction tube. With the help of taps (cranes) and winches attached to it, the cables are allowed to celebrate so that the suction pipe can be sunk into the water mass. A drag head is provided at the lower end of the suction pipe, which in use is dragged along the bottom of the water mass. During the dragging of the excavating device over the soil, a mixture of soil material and water is released by the excavating device. Under the influence of the vacuum created by one or more centrifugal pumps, the loosened bottom material is sucked upwards and then stored in the hold of the vessel. In the hold, which in the case of a trailing suction hopper dredger is called the hopper, the supplied bottom material precipitates and the excess water is drained off. Once the hold is full, the suction tube is retracted and the vessel moves to the aforementioned destination to deliver the aspirated bottom material.
    The maximum dredging depth of a trailing suction hopper dredger is generally determined by the length of the suction pipe that the vessel can handle. This maximum length depends, among other things, on the length of the ship. Due to a number of factors, the length of the suction pipe and thus the depth at which dredging can be done has been limited to a maximum of approximately 130 meters. One of the factors that adversely affects dredging at great depths is the occurring wave or swell. For example, at large wave heights and / or at certain wave frequency sequences, dredging is not possible because, as a result of the swell or wave stroke, the suction pipe, and in particular the excavating member thereof, is pressed into the ground or at least threatens to become. This can lead to damage to the excavation device, the suction pipe or even to the vessel. The season can also play a role. In the winter period the waves are often higher than outside this period. In some areas on Earth it is even only possible to dredge for an even shorter period, for example only in the summer, because only during that period the waves stay below a certain critical height on average. This limitation of the workability (or “up time”) for dredging at sea increases the costs of dredging and the speed thereof, for example when constructing the infrastructure for extracting gas and / or oil in certain areas, to a considerable extent extent. The limitation occurs particularly when dredging at large depths. The suction pipe then extends rather steeply and the excavating device therefore tends to dig into the soil.
    The aforementioned damage to the suction pipe, to the excavating device and / or to the vessel can occur when the excavating device receives a negative bottom speed. This means that as a result of the movements of the ship under the influence of the swell or wave stroke, the excavation device at the bottom of the suction pipe, despite a positive bottom speed (ie speed relative to the bottom) of the vessel in the direction of travel, the excavation device itself speed in the opposite direction. The phenomenon of negative drag head bottom speed is one of the factors that most restricts workability (or up-time) when dredging in deep water.
    To prevent the excavation device from having a negative bottom speed during the movement of the vessel in the direction of travel, for example, a very large and heavy vessel can be used. Because of its large mass and dimensions, the very large ship will be less affected by the waves and the movements of the vessel will therefore be smaller. Because of these smaller vessel movements, the excavation device will have smaller relative displacements and smaller relative displacement speeds. However, the drawback of this is that it is a very expensive solution. Moreover, building such heavy vessels takes relatively much time.
    It is an object of the present invention to provide a device, system and method in which the above-mentioned drawbacks of the prior art are obviated or at least reduced.
    It is also an object of the invention to provide a device, assembly and method in which the workability can be increased.
    It is a further object of the invention to provide a device, assembly and method with which dredging can be carried out at relatively large depths and with a limited risk of damage.
    According to a first aspect of the present invention, at least one of the stated objectives is achieved in a device for at least partially compensating for the impact of swell or wave action on the speed of an excavating device attached to a vessel, in particular a drag head, the device comprising: - a suction tube for sucking up bottom material, wherein the suction tube is articulated in a number of suction tube segments pivotable with respect to each other and wherein each of the suction tube segments extends obliquely backwards with respect to the direction of movement of the vessel; - a drag head provided at the end of the suction tube, which in use is dragged over the bottom for loosening and vacuuming up the bottom material; - cables provided between the suction pipe and the vessel for supporting individual suction pipe segments; - at least one lifting element for pivoting suction pipe segments relative to each other by lifting or allowing to celebrate at least one of the cables; - a control unit for controlling the lifting element, wherein the control unit is adapted to adjust the bottom speed of the excavating member by pivoting suction pipe segments.
    The suction tube segments can be moved upwards by lifting one or more cables with one or more lifting elements and being moved downwards by letting the cables celebrate and sinking the segments under the influence of gravity. A suitable pivoting of one or more suction pipe segments can effect a displacement of the excavating member coupled to the suction pipe.
    By properly arranging this displacement (e.g. with regard to timing, amplitude, speed and point of engagement), the resulting speed of the excavating member over the bottom can be controlled.
    A further advantage of this embodiment is that the device can not only be applied to new vessels that are yet to be built, but can also be applied to already existing vessels.
    In an embodiment of the invention, the suction pipe segments are formed by substantially straight tubes which are arranged in line with each other. As a result, the chance of blockage of the suction pipe, for example at the location of the connections between successive suction pipe segments, is small. Moreover, this means that the entire suction tube, which after use is lifted alongside the ship and / or stored on the deck of the ship, has a relatively small width. The total width of the suction tube in certain embodiments, for example when rubber couplings are used between the suction tube segments, need only be slightly wider than the diameter of the tube. The total width of the suction pipe (including couplings) is then of the same order of magnitude as the diameter of the pipe (for example approximately 1 m). A further advantage is that the force development in the suction tube is much more favorable than in a tube in which one or more suction tube segments are positioned obliquely forward, so that the chance of damage and / or the degree of wear can be limited.
    In a preferred embodiment of the invention, the control unit is designed to control said one or more lifting elements such that the bottom speed of the excavating member is controlled by lifting or allowing to celebrate at least one cable. A negative speed does not occur and the chance of damage is then relatively small.
    In a further embodiment the device comprises a suction pipe end segment, at one end of which the excavating member is arranged and at the other end of which a intermediate segment is arranged. This suction pipe segment is referred to herein as the end segment. It is the (intermediate) segment provided on the end segment that, at least in this embodiment, is displaced under the influence of the cable controlled by the control unit. With a suction pipe consisting of four segments, this means, for example, that the cable controlled by the control unit is attached to the third segment. The end segment and the segment linked thereto are closest to the element whose behavior is to be influenced, that is to say at the excavating member. Therefore, in many cases, displacement of these segments will have the most direct influence on the behavior of the excavator, yield the smallest time delay and require the least power.
    According to a preferred embodiment, the device comprises a speed determining unit, in particular a speed meter, for determining the speed of the excavating member relative to the bottom. The speed determining unit outputs a signal representative of the measured speed. This signal is fed back to the control unit. The control unit then determines the required control of the lifting element by using a control algorithm that makes use of the reduced bottom speed of the excavating member. In this way an active control of the movement of the excavating member and hence of the bottom speed thereof can be achieved.
    In a particular embodiment, the control unit is designed to receive the cable through the lifting element or to have it celebrated in such a way that the deviation between the measured bottom speed and a reference speed is reduced. For example, when the bottom speed of the excavator becomes smaller than the reference speed, the control unit will reduce the force exerted on the cable, so that the pipe segment attached thereto sinks down, thus increasing the speed of the excavator. On the other hand, as the speed increases, the force is increased, so that the relevant suction pipe segment is somewhat lifted. In a further embodiment, the reduction of the said deviation involves a minimization thereof.
    In a further embodiment of the invention, a device is provided in which the control unit is adapted to control the lifting element depending on one or more variables characteristic of the swell or wave stroke. This variable can for example be formed by the wave frequency. The current wave frequency can, for example, be measured with a wave frequency meter. The control unit can then, for example, be inactivated when the frequency of the waves falls below a predetermined value. The frequencies of the waves can also be determined by a specific wave buoy intended for this purpose. In a particular embodiment, the response characteristic of the control unit is made dependent on one or more of these swell or wave characteristic variables, for example a response characteristic that is adjusted depending on the predominant swell frequency (wave beat frequency).
    In other embodiments, the control unit is designed to receive the cable through the lifting element or to have it celebrated in such a way that a substantially constant force is exerted on the cable. With such a passive control, feedback of the measured soil speed of the excavation device is not necessary.
    In a particular embodiment the lifting element comprises one or more hydraulic lifting cylinders. In another embodiment the lifting element comprises an active winch. A combination of both types of lifting element is also possible. An example of such a combined device is described in U.S. Patent Application US 2007-0170296.
    The aforementioned speed meter for determining the bottom speed of the excavating member can have many embodiments. In a particularly advantageous embodiment, the speedometer comprises a Doppler sensor. The sensor is preferably arranged on the excavating member, although a different placement is also possible. In another embodiment, a position-determining unit, for example a GPS receiver, is used as an alternative or in addition to determine the speed thereof on the basis of the positions of the excavating device that change over time.
    According to a second aspect of the present invention, at least one of the objectives is achieved in an assembly of a vessel, in particular a trailing suction hopper dredger, provided with at least one device of the type defined herein.
    According to a third aspect of the present invention, at least one of the objectives is achieved in a method for at least partially compensating the impact of swell or wave stroke on the speed of an excavating device attached to a vessel, in particular a drag head of a vessel. trailing hopper dredger, the method comprising: - dragging a suction pipe fixed to the vessel and provided with an excavating member for loosening and sucking up bottom material, the suction pipe being articulated in a number of suction pipe segments pivotable relative to each other; - adjusting the bottom speed of the excavating member by lifting or lowering at least one of said suction pipe segments pivotable to each other.
    In a further embodiment of the invention, the method comprises continuously adapting the control of the said one or more lifting elements, so that the control can follow the wave stroke. In another embodiment, control takes place with short time intervals, for example twice per period of the dominant waves or once every 1 to 2 seconds or less. These time intervals are short enough to follow the relevant movements of the vessel.
    According to an embodiment, the method comprises of lifting or lowering at least one suction pipe segment to prevent the excavating member from moving in the opposite direction of the navigation direction.
    According to an embodiment, the method comprises only lifting and lowering the suction pipe segment coupled to the suction pipe end segment, in order to keep the construction and the control thereof simple, so that the costs thereof are low and the risk of malfunctions is relatively small.
    Further advantages, features and details of the present invention will be elucidated with reference to the following description of some preferred embodiments thereof.
    Reference is made in the description to the accompanying figures, in which:
    FIG. 1 is a side view of a trailing suction hopper dredger provided with a preferred embodiment of the device according to the invention;
    FIG. 2 a more detailed view of the preferred embodiment of FIG. 1;
    FIG. 3 is a diagram schematically showing the operation of the control unit;
    FIG. 4 is a graph of simulation results for the performance index as a function of the wave frequency, without driving, with passive driving and with active driving;
    FIG. 5 shows the minimum drag head speed as a function of the wave amplitude and the wave period; and
    FIG. 6 is a detail side view of a drag head provided with a bottom speed meter according to an embodiment of the invention.
    As explained earlier, when dredging in deep water, relatively large drag head displacements and displacement speeds can occur as a result of the movements of the vessel because the suction pipe is placed fairly steeply in the water. When the backward speed of the excavating device relative to the ship is greater than the bottom speed of the ship, the excavating device receives a negative bottom speed. Since, as previously stated, a negative drag head bottom speed limits dredging in deep water, the device according to an embodiment of the invention provides a device that prevents the excavating member from getting a negative bottom speed. The workability of the dredging device can hereby be increased.
    FIG. 1 shows an embodiment of such a device. The figure shows a system 1 consisting of a trailing suction hopper dredger 2 known per se, to which a suction pipe 4 is attached via a hinge 3. Suction tube 4 is composed of a number of consecutive suction tube segments, viz. A first suction tube segment 5, a second suction tube segment 6, a third suction tube segment 7 and a last, fourth suction tube segment 8. The suction tube segments 5-8 are slightly pivotable relative to each other by means of respective hinge constructions 9. The aforementioned drag head 10 is arranged on the last, fourth suction pipe segment 8. The drag head 10 can be dragged along the bottom B in known manner when the trailing suction hopper dredger 2 moves in the direction of travel (positive direction Pv).
    The suction tube is made of steel and has such a weight that it would sink downwards if the suction tube was not supported in any way. The support takes place by means of a number of cables connected to the suction tube. In the embodiment shown, the first suction pipe segment 5 is supported by a first cable 16, the second suction pipe segment 6 by a second cable 17, the third suction pipe segment 7 by a third cable 18 and the fourth suction pipe segment 8 by a fourth cable 19. Each of the cables 16-19 is coupled to the vessel by a respective crane 12-15 provided with a lifting element. The cranes are adapted to determine the depth of the relevant part of the suction pipe 4 by varying the length of the cable between the crane and the relevant suction pipe segment.
    The suction tube preferably meets a number of requirements. First of all, the minimum absolute angle between each of the suction pipe parts 5-8 on the one hand and the vertical on the other hand must be greater than a predetermined minimum value in order to prevent the cables 16-19 from being no longer under tension during dredging.
    Furthermore, there is a requirement that the maximum relative angle between successive suction pipe segments 5-8 should not be greater than a predetermined value, for example 30 °, because otherwise the hinge constructions 9 wear too quickly, which could shorten the life of the suction pipe. Furthermore, the minimum relative angle between the third and fourth suction pipe segment 7,8 must have a certain minimum value. This angle must be greater than 0 ° by a predetermined amount, because only then can the forward speed error of the drag head 10 be compensated by raising the third suction pipe segment 7. In a preferred embodiment, it is decided to leave the relative angle close to 20 ° because then the driving stroke of the relevant lifting element is greatest within the limits of the aforementioned maximum relative angle between the third segment 7 and the fourth segment 8.
    Fig. 2 shows the lower end of the suction pipe 4, that is to say a part of the third segment 7, the fourth segment 8 and the drag head 10. It is also schematically shown that the length L of the cable 18 can be adjusted by with the aid of a lifting element 20. As in the embodiment shown, lifting element 20 can comprise a hydraulic cylinder 21 which is attached to a crane of the vessel 2. By varying the length of this cylinder 21, the length of the cable 18 between the lifting element 20 and the relevant suction pipe segment 7, 8 can be adjusted accordingly. As the length of the lifting cylinder 21 becomes larger (which is shown in the figure with a double arrow Pi), the relevant length of the cable 18 decreases, while when the length of the lifting element 20 becomes smaller, the relevant length of the cable 18 becomes larger. The lengths of one or more of the other cables can also be adjusted. By individually controlling the length of the respective cable, the position of each of the suction pipe segments 5-8 relative to the vessel 2 can then be varied. This variation will be used according to the invention if, when the swell or wave stroke threatens to cause the drag head 10 to cause a negative speed (i.e. a displacement in the direction opposite to the sailing direction Pv), one or more of the suction pipe segments 5 , 8 to pivot such that the pivoting movement at least partially compensates for the swell or wave stroke. A negative speed is thus prevented.
    The speed of the drag head 10 can be influenced by pivoting one or more of the suction pipe segments in the correct manner (i.e. with a correct timing, speed, amplitude and the like). It is possible to operate two or more lifting elements 12-15 simultaneously or one after the other to cause the different segments to move relative to each other. However, it has been found that in many common cases the adjustment of the length of one of the cables, in particular the cable 18 with which the third and fourth segments 7, 8 can be pivoted, can be used. Since the third cable 18 is closest to the pipe segment with which the drag head 10 can be influenced, in a certain embodiment only the length of the third cable 18 is adjusted.
    The lifting element 20 for changing the length of the third cable 18 is connected via an electrical connection line 24 to a control unit 25. This control unit may comprise a computer programmed in a suitable manner or a similar electrical control. The control unit 25 herein comprises an electronic controller 26 which is adapted to perform calculations via a calculation rule stored in the controller. On the basis of these calculations, the control signal generator 27 from the control unit 25 sends control signals to the lifting element 20 so that the lifting element can influence the movement of the drag head.
    The control of the lifting element 20 can be carried out passively or actively. Fig. 3 shows a schematic diagram of the design of the control unit 25. In order to control the drag head bottom speed (VS | eep head) with the control unit, the bottom speed is measured and compared with a desired reference speed (Vref). If the bottom speed is not equal to the reference speed, an error ε is measured and the controller 26 will take action to reduce this error. This results in a control output force (F-control)> that can be supplied by the lifting element 20. The signal generator 27 then generates a signal and sends it to the lifting element 20, which on the basis of the received signal will cause the third pipe segment 7 (and the upper part of the end segment 8) coupled thereto is moved up or down. This again causes a change of the said error ε and a further control of the lifting element 20. The process of measuring the bottom speed, comparing the measured bottom speed with a reference speed, determining the difference between the two speeds, determining it on the basis of the measured difference (and of control data stored in advance on the controller 26) determining the required control force Fcontrol and sending a control signal representative of the required control force to the said one or more lifting elements 20 is repetitive (wherein the repetition frequency must be greater than the frequency of the waves).
    For example, if the force Feq is the force exerted on the third suction pipe segment 7 via the cable 18 in an equilibrium configuration, P is a proportional control parameter and the error ε is the speed error ε = Vsieep head - Vf, in a certain embodiment the control force Fbestunng to be exerted by the lifting element 14 is equal to Feq + Ρ · ε. This means that the force in the cable 18 will be reduced when, for example, the drag head bottom speed Vsieep head becomes smaller than the reference speed V ref. If the force is reduced, this means that the relevant suction pipe segment 7 will start to sink. If the suction pipe segment 7 sinks, it will cause the lower end of the suction pipe segment 8 to be pulled slightly forward, which will increase the speed Vsieep head of the drag head. Similarly, when the drag head speed is greater than the reference speed, the force in the cable 18 will be increased, so that the third suction pipe segment 7 is lifted up slightly. This results in a rearward (opposite to direction Pv) displacement of the suction pipe segment 8, which reduces the speed of the drag head.
    The size of the proportional control parameter Pe depends on a large number of factors and will have to be determined on a case-by-case basis (for example, depending on the ship design). The proportional control parameter can also be made dependent on the current swell or wave stroke. To this end, the vessel can be provided with a measuring instrument 41 (shown schematically in Figure 1) for measuring a variable characteristic of the swell or wave stroke, for example the wave frequency. Depending on the value of the measured variable, the control characteristic of the control unit can then be adjusted in order to be able to realize an even further improvement of the swell or wave stroke compensation. The control characteristic can for example be adjusted by adjusting the value of the control parameter Ρε, but other ways of adjusting the control characteristic are also conceivable. The control parameter Ρε can also be selected to be zero. In this special case there is no feedback of the drag head speed and the control is passive.
    Instead of a proportional controller or in addition to it, the controller can also be designed to control the one or more lifting elements with the aid of self-learning systems in general or "fuzzy logic" systems and neural networks in particular.
    In order to measure the performance of the control unit, a performance index in the form of the so-called average integral absolute error (MIAE for short) can be introduced. The MIAE is the average absolute value of the speed error ε in the time interval in which the control unit is switched on. For example, the MIAE performance index can be defined as:
    The performance of the control unit 25 depends inter alia on the frequency of the wave movements. FIG. 4 shows the simulation results of the aforementioned MIAE as a function of different wave frequencies, without and with the control according to the invention. Reference number 33 shows the results for the non-controlled system, reference number 34 the results for the case that the proportional control parameter P is equal to 0 (P = 0) and reference number 35 the results for an appropriate value of P. From Fig. 4 it is clear that in the case of the non-controlled system, large variations in the performance index occur, depending on the frequencies. It has been found that the peaks in the MIAE of the uncontrolled system are approximately at the same position as the peaks of the stamping movements of the vessel 2. This means that the movement of the vessel is actually translated into movements of the drag head 10 when the suction pipe 4 has not been sent.
    The results indicated by 35, in which the speed of the drag head 10 is actively controlled, show that the performance index over the entire frequency range is lower than in the case of the non-controlled system. This means that the error occurring, that is to say the difference between the speed of the drag head and the reference speed, is a lot smaller over the entire frequency range. It can be concluded that the control unit decreases the speed error over the entire frequency range.
    In the special case that the control stroke (Fcontrol) is equal to the equilibrium force (Feq), that is to say that when a constant force is exerted on the cable 18, an improvement also occurs. In Fig. 4, for example, a dashed line 34 indicates that for a large part of the frequency range, in the case that P = 0, the MIAE, and hence the deviation between the speed of the drag head and the reference speed, than that of the uncontrolled system. From a certain wave frequency, for example the frequency indicated in Fig. 4 with reference number 40, also in this case the control of lifting element 20 will have a positive effect on the performance of the system. A constant force can be applied, for example, by connecting cable 18 via a guide wheel with a fixed mass. Another way is to control the lifting element 20 by the control unit 15 such that the lifting element exerts a constant force on the cable 18. This can be achieved, for example, by providing the lifting element 20 with a force transducer which is coupled to the control unit 25. Depending on the force measured by the force transducer, the control unit can suitably control the lifting element 20.
    The effect of the described control of the suction tube 4 on the workability is then calculated for a number of situations. Firstly, information about wave heights and wave periods is available, which information is currently being collected via satellites. A so-called scatter diagram is used for this, in which percentages are indicated with which waves of a certain interval of wave periods (in seconds) and a certain interval of wave amplitudes (in meters) occur. Starting from a predetermined reference speed, for example 1 meter per second, the speed of the drag head 10 can then be calculated. FIG. 5 shows a figure showing the minimum drag head speed as a function of the wave amplitude and the wave period. Reference number 30 indicates the situation of the uncontrolled suction pipe, while reference number 31 indicates the situation with the controlled suction pipe. It is clearly visible that the minimum drag head speed in the unsteered situation (reference number 30) can become smaller than 0, which is unacceptable. In this case (reference number 31) in which the suction pipe 4 is controlled, the minimum drag head speed never decreases below 0. This means that if the suction pipe 4 is not controlled, dredging cannot be carried out for part of the time, while with the system switched on can always be dredged, regardless of the height of the waves and / or the wave period (wave frequency).
    FIG. 6 shows an embodiment of the drag head 10 which is provided with a preferred embodiment of a speed meter 36. The drag head 10 comprises in a known manner a mouth 37 via which loosened bottom material can be sucked up. To rinse the bottom material loose, the end of the drag head 10 is provided with a release mechanism 38. To determine the speed of the drag head 10 relative to the bottom B, a multi-beam doppler sensor 36 can be used. The multi-beam doppler sensor takes advantage of the fact that the frequency of the sound waves emitted by the source changes when reflected by a moving object. The same applies when the multi-beam doppler sensor itself moves and the sound waves are reflected back by a stationary object (i.e. the bottom). The level of the frequency change between the transmitted and received audio signal is directly coupled to the speed of the drag head 10. A signal representative of the measured speed is routed via a connecting cable 39 to the control unit 25 and used by the controller 26 to control force Fcontrol.
    In the illustrated embodiment, only a single multi-beam Doppler sensor 36 is shown. In other embodiments, however, a number of sensors are provided which use different frequencies and which extend at different angles to the bottom in order to increase the accuracy of the speed measurements.
    The present invention is not limited to the preferred embodiments thereof described herein. The rights sought are defined by the following claims, within the scope of which many modifications can be envisaged.
    权利要求:
    Claims (18)
    [1]
    Device for at least partially compensating for the impact of swell or wave impact on the speed of an excavating device attached to a vessel, in particular a drag head, the device comprising: - a suction tube for sucking up bottom material, wherein the suction tube articulates is embodied in a number of suction pipe segments that are pivotable relative to each other and wherein each of the suction pipe segments extends obliquely backwards with respect to the direction of movement of the vessel; - an excavating member provided at the end of the suction tube, which in use is dragged over the bottom for loosening and vacuuming up the bottom material; - cables provided between the suction pipe and the vessel for supporting individual suction pipe segments; - at least one lifting element for pivoting suction pipe segments relative to each other by lifting or allowing to celebrate at least one of the cables; - a control unit for controlling the lifting element, wherein the control unit is adapted to adjust the bottom speed of the excavating member by pivoting suction pipe segments.
    [2]
    Device as claimed in claim 1, wherein suction pipe segments are formed by substantially straight pipes which are arranged in line with each other.
    [3]
    Device as claimed in any of the foregoing claims, wherein the control unit is adapted to control the lifting element depending on one or more variables characteristic of the swell or wave stroke.
    [4]
    Device as claimed in claim 3, wherein the control unit is coupled to a measuring instrument for measuring the one or more variables characteristic of the swell or wave stroke, preferably the wave frequency.
    [5]
    Device as claimed in any of the foregoing claims, comprising a suction pipe end segment, at one end of which the excavating member is arranged and at the other end a connecting segment is arranged and wherein the cable to be picked up and held is attached to the intermediate segment and wherein the control unit is designed to keep the bottom speed of the excavating member positive by lifting or allowing to celebrate at least one cable.
    [6]
    Device as claimed in any of the foregoing claims, wherein the control unit is designed to receive the cable or to have it held by the lifting element in such a way that a substantially constant upward force is exerted on the cable.
    [7]
    7. Device as claimed in claim 6, wherein a mass is coupled to the cable for providing the constant upward force.
    [8]
    Device as claimed in any of the foregoing claims, comprising speed-determining means, in particular a speed meter, for determining the speed of the excavating member relative to the bottom, wherein the control unit is designed to control the lifting element on the basis of the measured bottom speed of the excavation device.
    [9]
    Device as claimed in any of the foregoing claims, wherein the control unit is adapted to cause the lifting element to exert a force on the cable which is determined by an equilibrium force (Few) for maintaining equilibrium and a proportional control parameter (Ρε).
    [10]
    Device as claimed in any of the foregoing claims, wherein the relative angle between the end segment and the intermediate segment connected thereto is between 0 and 30 degrees, preferably between 15 and 30 degrees.
    [11]
    11. Assembly comprising a vessel, in particular a trailing suction hopper dredger, provided with at least one device according to one of the preceding claims.
    [12]
    12. Method for at least partially compensating for the impact of swell or wave action on the speed of an excavating device attached to a vessel, in particular a drag head of a trailing suction hopper dredger, the method comprising: - dragging a vessel over the bottom vessel-mounted suction pipe provided with a drag head for loosening and sucking up bottom material, the suction pipe being articulated in a number of suction pipe segments pivotable relative to each other; - adjusting the bottom speed of the excavating member by lifting or lowering at least one of said suction pipe segments pivotable to each other.
    [13]
    A method according to claim 12, comprising continuously or at short intervals controlling said one or more lifting elements.
    [14]
    A method according to claim 12 or 13, comprising only lifting and lowering the suction pipe segment coupled to the suction pipe end segment.
    [15]
    A method according to any of claims 12-14, comprising applying a substantially constant force to said one or more suction pipe segments.
    [16]
    A method according to any of claims 12-15, comprising measuring the speed of the excavating member relative to the bottom and adjusting it based on the measured bottom speed of the excavating member.
    [17]
    A method according to any of claims 12-16, comprising applying a force to the suction pipe segment that is determined by a balance force (Few) for maintaining balance and a proportional control parameter (Ρε).
    [18]
    A method according to any one of the preceding claims, wherein a device according to one of claims 1 to 15 is applied.
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    同族专利:
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US3734564A|1970-04-27|1973-05-22|Mckay C|Endless bucket dredge with articulated ladder and swell compensator|
    US3739503A|1970-08-11|1973-06-19|G Barker|Hydraulic dredge having articulated ladder and swell compensator|
    US3949496A|1972-01-28|1976-04-13|Konig Jan De|Wave compensating system for suction dredgers|
    JPS5145169B2|1973-03-16|1976-12-02|
    EP0009516B1|1978-09-29|1982-06-02|Ballast-Nedam Groep N.V.|Method and device for maintaining tools at a level below a water surface|
    JPS5869942A|1981-10-23|1983-04-26|Mitsubishi Heavy Ind Ltd|Method and device for regulating contact pressure of drag head of dredger|
    JPS5938432A|1982-08-27|1984-03-02|Mitsubishi Heavy Ind Ltd|Drag head depth displayer|
    JPS5965134A|1982-10-06|1984-04-13|Mitsubishi Heavy Ind Ltd|Controller for drag arm|
    NL1011629C2|1999-03-22|2000-09-27|Marine Structure Consul|Method for positioning an excavating tool with respect to a vessel as well as a vessel with excavating tools.|NL2006782C2|2011-05-13|2012-11-14|Ihc Holland Ie Bv|Dredger provided with a remotely operable dredging vehicle, and method for dredging using such a dredger system.|
    CN107975082A|2017-12-07|2018-05-01|浙江海洋大学|A kind of strand in dredger cuts unit|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    NL2001473A|NL2001473C2|2008-04-11|2008-04-11|Excavating component speed oscillation or undulation influence compensating device, has excavating component set at end of sucker for dragging bed to loosen and suck bed materials, and control unit setting bed speed of excavating component|
    NL2001473|2008-04-11|
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