A device for depositing material under water

Abstract

 The invention relates to a device for depositing material under water. The device is provided with an elongated chute, which is connected near its upper end to a supporting structure at least partially located above the water surface. A frame is provided near the bottom end of said chute, which frame (5) is provided with a tube section (4) forming the bottom end of said chute, and with propelling means (6), by which the frame (5) and the bottom end of the chute can be moved in directions perpendicularly to each other. The frame (5) is coupled, using spring means, to a supporting member secured to the bottom end of said chute, said supporting member being provided with a second tube section (2), which extends into the first tube section (4) secured to the frame (5), in such a manner that the two tube sections (2,4) are telescopically movable in the longitudinal direction of the chute with respect to each other.

Description

[0001] The invention relates to a device for depositing material under water, said device being provided with an elongated chute, which is connected near its upper end to a supporting structure at least partially located above the water surface, whilst a frame is provided near the bottom end of said chute, said frame being provided with a tube section forming the bottom end of said chute and with propelling means, by which the frame and the bottom end of the chute can be moved in directions perpendicularly to each other.

[0002] Such devices are for example known from Dutch Patent Application No. 8102244 and European Patent Applications Nos. 0002991 and 0450675.

[0003] With these known constructions the comparatively heavy frame, which is provided at the bottom end of the chute, must follow the heaving motion of the supporting structure at least partially located above the water surface, usually a vessel, when no special provisions have been made. In order to overcome this drawback provisions are made in the supporting structure at least partially located above the water surface, so as to provide motion compensation, in such a manner that the chute and the comparatively heavy frame provided at the bottom end of the chute do not have to follow the heaving motions of the vessel, at least not completely.

[0004] The object of the invention is to obtain an improvement of such a device.

[0005] According to the invention this can be achieved in that said frame is coupled, using spring means, to a supporting member secured to the bottom end of said chute, said supporting member being provided with a second tube section, which extends into the first tube section secured to the frame, in such a manner that the two tube sections are telescopically movable in the longitudinal direction of the chute with respect to each other.

[0006] A suitable spring suspension of the frame to the bottom end of the chute will ensure that during operation the upward and downward movement of the frame, and thus also of the bottom end of the tube section supported by the frame from which the material to be deposited exits, is considerably reduced in comparison with the conventional constructions, which makes is possible to deposit the material on the desired place with considerably enhanced accuracy. Furthermore it is not necessary to move the entire chute upward and downward in order to compensate the heaving motion, resulting in a reduced wear of the chute and of the means supporting the chute, such as hoisting cables and the like. A further advantage is that it is no longer necessary to provide means for compensating the heaving motion on the supporting structure at least partially located above the water surface, which means a saving of space and weight at that location.

[0007] Sensors functioning to locate the frame, which may be attached to the frame, furthermore keep the frame at a substantially fixed, shorter distance from the bottom of the sea than is the case with the conventional constructions, which also leads to better results. A good feed-through of material through the frame is still ensured thereby, as a result of the use of the two tube sections, which are telescopically movable with respect to each other.

[0008] An effective and simple construction of the spring means can be obtained when said means are comprised of a few hydraulic setting cylinders provided between the frame and the supporting member, whereby the cylinder spaces of said setting cylinders, at least the cylinder spaces located on one side of the pistons of the setting cylinders, are in communication with a hydraulic accumulator, which is held under pressure by means of a gas.

[0009] The invention will be explained in more detail hereafter with reference to the accompanying Figures, which illustrate a possible embodiment of the device according to the invention.

[0010] Figure 1 is an elevation view of the frame to be provided at the bottom end of a chute (not shown), in the position in which the two tube sections are extended with respect to each other.

[0011] Figure 2 is an elevation view corresponding with Figure 1, wherein the tube sections are telescoped into one another.

[0012] Figure 3 is a larger-scale, sectional view of Figure 2.

[0013] Figure 4 diagrammatically shows two possible embodiments of a mechanism intended for effecting an even movement of the two tube sections with respect to each other.

[0014] Figure 5 shows a diagram of the hydraulic circuit for the setting cylinders.

[0015] Figure 6 diagrammatically shows a further possibility for guiding the two tube sections with respect to each other.

[0016] Figure 7 is a plan view of Figure 6.

[0017] The frame shown in Figures 1 - 3 comprises a funnel-shaped part 1, which is joined by a vertically extending tube section 2 at its bottom end. Four racks 3, extending in the longitudinal direction of the tube section 2, are provided at regular angular distances from each other on the outer circumference of said tube section.

[0018] The tube section 2 is surrounded by a tube section 4 extending concentrically around the tube section 2, said tube section 4 being accommodated in a frame 5 built up of a number of tubes. The frame inter alia supports a number of propelling means 6, in a manner known per se, said means being built up of hydraulic motors 7 and screws 8 to be driven by the hydraulic motors 7. Seen in Figure 2 two propelling means 6 are provided, by means of which the frame can be moved in a direction perpendicularly to the plane of the drawing, as well as two propelling means, by which the frame can be moved in a direction parallel to the plane of the drawing.

[0019] The upper end of the funnel 1 is connected to the bottom end of the chute (not shown), which may be a chute as described and depicted in the above-mentioned references. The funnel 1 is thereby suspended from hoisting cables 9, the free ends of said cables being passed over discs 10 secured to the funnel 1 and being clamped down on said funnel, as shown in Figure 3. Thus the frame with the tube sections and the chute (not shown) can be moved upward and downward by means of the hoisting cables 9 in a manner known per se.

[0020] The bottom ends of the cylinders 11 of hydraulic setting cylinders are secured to the frame 1, regularly spaced from each other. The piston rods 12 (Figure 5) projecting from the upper ends of the cylinders 11 are secured to the funnel 1 with their upper ends. Said piston rods are thereby surrounded by protective sleeves 13 likewise fixed to the funnel 1, which sleeves can reciprocate along with the piston rods, therefore, and which also surround the cylinders 11 in the telescoped position shown in Figure 2, in which the tube section 2 is entirely accommodated within the tube section 4.

[0021] As is apparent from Figures 3 and 4 pinions or gears 14, which are in engagement with the racks 3, are rotatably journal led near the upper side of the frame 5 surrounding the outer tube section 4. As is shown in the right-hand part of Figure 4, said pinions or gears 14 may be coupled by means of shafts 15 and universal joints 16. Another possibility, as illustrated in the left-hand part of Figure 4, is to couple the pinions or gears 14 by means of shafts 17 and bevel gearings 18.

[0022] It will be apparent that when the tube sections 2 and 4 move telescopically with respect to each other, this mechanical connection between the outer tube section 4 and the inner tube section 2, by means of the racks 3 and the mutually coupled pinions or gears 14, ensures an even reciprocating movement of the tube sections with respect to each other, whilst preventing said tube sections from being undesirably pulled out of square.

[0023] Furthermore it is preferred to provide a few vertical guide strips (not shown) on the outside of the inner tube section 2, said guide strips cooperating with guide rollers provided on the inside of the outer tube section 4, so as to prevent the tube sections from pivoting about the central axes of the tube sections with respect to each other.

[0024] As is furthermore shown in the Figures two arms 21 and 22, which are pivotable about horizontal pivot pins 19 and 20 extending parallel to each other, are provided near the bottom side of the frame 5. The free ends of said arms are connected to a coupling piece 25 by means of pins 23 and 24 extending parallel to the pins 19 and 20, to which coupling piece 25 a supporting arm 26 is pivotally coupled. A screw 28 to be rotated by means of a hydraulic motor 27 is provided at the upper end of said supporting arm 26, whilst sensors 29, cameras or the like may be mounted on the bottom end of the supporting arm 26.

[0025] The arms 21 and 22 and the supporting arm 26 supported by said arms can be pivoted from the storage position shown in Figures 2 and 3 to the operating position shown in Figure 1 by means of a pivoting motor mounted near the pivot pin 19, the construction of the driving gear for pivoting the arms 21 and 22 being such that in the operating position shown in Figure 1 the arms 21 and 22 can pivot freely to a certain extent, so that in use the position of the supporting arm 26 is vertically adjustable by means of the screw 28 to be driven by the hydraulic motor 27.

[0026] Of course further sensors, scanners or the like, which may or may not be mounted on pivotable arms, may be connected to the frame if desired.

[0027] As is apparent from Figure 5, the cylinder space of each cylinder 11 that is located on the side of the piston rod 12 of the piston 30 in the cylinder is connected, by means of a line 31, to a chamber 32 in which a piston 33 is located. The various pistons 33 are secured to a common shaft 34.

[0028] Upon movement of the pistons 30 in the cylinders 11 a fluid will flow to or from the chambers 32, which will result in movement of the pistons 33. Since the pistons 33 are interconnected, all pistons will traverse the same path.

[0029] By means of a line 34' each of the chambers 32 is connected to a control cylinder 35 at the side of the piston 33 remote from the side on which a respective line 32 is connected, a control piston 36 being present inside said control cylinder. The control piston 36 is connected to a piston 38 by means of a piston rod 37, said piston being located inside a cylinder 39, whose cylinder space is shut off from the cylinder space of the cylinder 35.

[0030] A line 40 connects the cylinder 39, at the side of the piston 38 in the cylinder 39 remote from the piston 36, to each of the cylinders 11, at the side of the piston 30 in the respective cylinder 11 remote from the piston rod in question.

[0031] At the side of the piston 38 directed towards the piston 36 the internal space of the cylinder 39 is connected, via a line 41, to a gas-filled bellows 42, which is exposed to the water pressure during operation.

[0032] At the side of the piston 36 remote from the side of the cylinder space to which the line 34 is connected the interior of the cylinder 35 is connected, via a line 44', to an accumulator 43. Inside the accumulator 43 the oil is held under pressure by means of a gas.

[0033] A piston rod 44, which is in line with the piston rod 37, is secured to the piston 36 at the side of the piston 36 remote from the piston rod 37, said piston rod 44 connecting the piston 36 to a piston 46 located in a cylinder 45. Lines 47 and 48 for the supply and discharge of pressurized oil are connected near the two ends of the cylinder 45.

[0034] During normal operation the frame 5 with the tube section 4 accommodated therein will at least substantially be in the extended position shown in Figure 1, whereby the frame 5 is coupled, by means of the hydraulic setting cylinders 11, 12, to the funnel 1 connected to the bottom end of the chute. The pistons 30 secured to the piston rods 12 will approximately occupy the position diagrammatically illustrated in Figure 5.

[0035] When the chute and the piston rods 12 connected thereto via the funnel 1 move upward and downward the pistons 30 can reciprocate inside the cylinders 11, as a result of which oil can flow from the spaces above the pistons 30 in the cylinders 11, to and from the spaces to the left of the pistons 33 in the chambers 32, seen in Figure 5, or flow back from there. This will result in a movement of the pistons 33 within the chambers 32 and thus in a movement of the control piston 36 within the cylinder 35 as well, which movement is influenced by a fluid present on the left-hand side of the piston 36, seen in Figure 5, which is held under pressure by means of the compressible and expandable gas contained within the accumulator 43.

[0036] This will also cause the piston 38 to move, as a result of which a fluid is pressed into the spaces under the pistons 30, seen in Figure 5, or can flow from said space to the cylinder 39. Since the fluid flowing out of the spaces above the pistons 30, seen in Figure 5, flows into spaces located to the left of the pistons 33 in the chambers 32, seen in Figure 5, and fluid flows out of said chambers, from the spaces located to the right of the pistons 33, to the control cylinder 35 thereby, or vice versa, and fluid flows into or out of the spaces under the pistons 30 in the cylinders 11 in conjunction therewith, a same movement of the pistons 30 with the piston rods 12 secured thereto is effected by means of said interconnected pistons 33. By thus effecting a same movement of the piston rods 12 as a result of the "hydraulic coupling", a parallel movement of the tube sections 2 and 4 with respect to each other is effected. Using this hydraulic coupling thus has the same effect as using the above-described racks 3 and the pinions of gears 14 coacting therewith.

[0037] In most cases it will suffice to provide either the above-described "hydraulic coupling", or the mechanical coupling effected by means of the racks 3 and the pinions or gears 14.

[0038] When it is decided only to use the mechanical coupling, the chambers 32 and the interconnected pistons 33 may be left out, and the spaces above the pistons 30 in the cylinders 11, seen in Figure 5, are directly connected with the space to the right of the piston 36 in the cylinder 35.

[0039] Furthermore it will be apparent that the setting cylinders 11, 12, aided by the accumulator 43 being under gas pressure, provide a spring suspension of the frame 5 with the parts supported by said frame 5, as it were. Thereby the movement of the piston rods 12, and thus the action of
the "spring system", is influenced by the pressure of the gas contained within the accumulator 43.

[0040] Furthermore an influencing of the "spring system" is effected in dependence on the depth of the water by means of the bellows 42, by means of which a pressure, which increases along with the depth of the water, is effected in the space to the right of the piston 38 in the cylinder 39.

[0041] A further influencing of the spring system can be effected by influencing the pressure on either side of the piston 46 in the cylinder 45, via the supply and/or discharge of a pressurized medium through the lines 47 and 48. The pressure on either side of the piston 46 during operation will be influenced in dependence on the sensed vertical movements of the frame 5.

[0042] By a suitable selection of the size of the various pistons and piston rods and also of the pressure in the accumulator 43 and the regulation of the pressure on either side of the piston 46, it is possible to effect, at least substantially so, that the frame 5 does not follow the heaving motions of the funnel 1 connected to the vessel or the like. As a result of this it is possible to hold the bottom end of the tube section 4 at a comparatively short distance from the place where material is to be deposited, as a result of which an optimum use of the material to be deposited can be realised. Also the sensors, cameras or the like mounted on the supporting arm 26 can be held at least substantially stationary at an optimum height above the bottom surface, a pipeline to be covered or the like, so that an optimum operation of these parts can be achieved as well.

[0043] A fluid can be pressed into the spaces above the pistons 30 in the cylinders 11 by means of a pump (not shown), so as to move the frame 5 into the position shown in Figure 2 with respect to the funnel 1.

[0044] Figures 6 and 7 show a further possibility of guiding the tube sections 2 and 4 with respect to each other. Four guide wheels 51 are thereby mounted on one of the tube sections, the tube section 4 in the illustrated embodiment, in positions shifted 90° with respect to each other, said guide wheels being freely rotatable on horizontal shafts 52 secured to the tube section 4. The guide wheels cooperate with vertical guide strips 53 disposed on either side of the respective wheels 51, which are secured to the other tube section, tube section 2 in the illustrated embodiment.

[0045] Also in this manner an adequate guiding of the tube sections during upward and downward movement can be realised.

Claims

1. A device for depositing material under water, said device being provided with an elongated chute, which is connected near its upper end to a supporting structure at least partially located above the water surface, whilst a frame is provided near the bottom end of said chute, said frame being provided with a tube section forming the bottom end of said chute and with propelling means, by which the frame and the bottom end of the chute can be moved in directions perpendicularly to each other, characterized in that said frame is coupled, using spring means, to a supporting member secured to the bottom end of said chute, said supporting member being provided with a second tube section, which extends into the first tube section secured to the frame, in such a manner that the two tube sections are telescopically movable in the longitudinal direction of the chute with respect to each other.

2. A device according to claim 1, characterized in that said spring means are comprised of a few hydraulic setting cylinders provided between the frame and the supporting member, whereby at least the cylinder spaces located on one side of the pistons of the setting cylinders are in communication with a hydraulic accumulator, which is held under pressure by means of a gas.

3. A device according to claim 2, characterized in that cylinder spaces located on one side of the pistons of said setting cylinders are connected with a control cylinder accommodating a control piston, which can be moved under gas pressure under the influence of a fluid flowing into or out of said setting cylinders, whilst said control piston is connected to a further piston, which is located inside a cylinder, which is in communication at one side of said further piston with the cylinder spaces located at the other sides of the pistons of said setting cylinders.

4. A device according to claim 3, characterized in that the cylinder space accommodating said further piston is in communication with a gas-filled bellows, which is exposed to the water pressure prevailing near the frame during operation, at that side of said further piston which is remote from the cylinder space being in communication with the setting cylinders.

5. A device according to claim 3 or 4, characterized in that said control piston is connected to a further piston, which is located inside a cylinder space which is provided at both ends with means for supplying and/or discharging a pressurized medium.

6. A device according to any one of the preceding claims 3 - 5, characterized in that the cylinder spaces on one side of the pistons of the setting cylinders are each connected to one end of a chamber accommodating a piston, whereby the pistons located inside the chambers are interconnected and whereby the other ends of said chambers are connected to the control cylinder accommodating the control piston.

7. A device according to any one of the preceding claims, characterized in that racks extending in the longitudinal direction of one of the tube sections are connected to the tube section in question, said racks being in engagement with mutually coupled pinions or gears, which are rotatably coupled to the other tube section.

8. A device according to any one of the preceding claims, characterized in that the piston rods of the setting cylinders are connected to the bottom end of the chute, whilst the cylinder casings of the setting cylinders are connected to the frame.

9. A device according to claim 8, characterized in that the protective sleeves surrounding the piston rods are connected to the bottom end of the chute, the length of said sleeves being such that said piston rods are surrounded by said protective sleeves at all times.

10. A device according to any one of the preceding claims, characterized in that a supporting arm is coupled to the frame by means of arms forming a parallellogram mechanism, whereby at least one sensor or the like is coupled to said supporting arm, as well as a screw to be driven for vertical adjustment of said supporting arm.

11. A device according to claim 10, characterized in that said parallellogram mechanism can be collapsed into a non-working position.

12. A device according to any one of the preceding claims, characterized in that one of the tube sections is provided with superposed guide wheels in several positions shifted through an angle of the central axis of said tube sections with respect to each other, said guide wheels cooperating with vertical guide strips disposed on either side of said guide wheels.

Drawing