ES2684359B1 - SUBMERGED AUTONOMOUS DRAGING EQUIPMENT - Google Patents

Description

SUBMERGED AUTONOMOUS DRAGING EQUIPMENT

DESCRIPTION

Field of the Invention

The present invention relates to the dredging industry of sea beds, lakes or sediments and to the mitigation of the environmental impact of said activity. In particular, the present invention relates to a device and a dredging procedure, wherein the equipment travels autonomously on the bottom by dredging by suction, while collecting and transmitting continuous information from the medium.

Background of the invention

A dredging consists of the removal, by various techniques, of particles of sand, clay, silt and other substances carried by water currents (sediments), which are deposited in the bottoms of coastal areas, ports and estuaries, lakes, reservoirs and bottoms of navigable rivers.

Dredging operations have been carried out since the 19th century, being a type of activity in which innumerable advances have taken place, there are currently various systems conditioned by the type of material to be dredged, the location of the dredging point, etc. Currently, dredging activities are being reoriented due to the environmental impact that occurs during them, an impact that must be evaluated beforehand and mitigated during the operation, taking appropriate measures.

The current dredging process is mainly carried out using suction or hydraulic dredgers and mechanical dredgers, which we review below and for which various technical deficiencies have been identified.

Mechanical dredgers are those that use exclusively mechanical equipment or means for digging and extracting the material. It is the oldest type of dredger and has evolved a lot throughout history thanks to the advancement of industrial technology and maritime works. In general, the use of these dredgers is recommended for work in confined areas and can easily operate with loose and heavy materials, although they are also used for all types of floors. The excavated material usually has a low water content, since it is not necessary to dilute the material. The performance is usually lower than that of hydraulic dredgers since the type of work is discontinuous, and the finish is less uniform. Among them, several types are distinguished depending on the mechanical means with which the material is extracted.

Currently, retro excavation dredgers are still used very frequently. In them the backhoe bucket shows its concave face back, so that during the excavation the bucket approaches the pouring area. The spoon penetrates from top to bottom in the layer of material to be dredged. This type of dredger has developed a lot in recent years and currently, all dredging fleets have backhoe dredgers.

In mechanical dredging, the buckets or backhoes used are not completely watertight, generating material suspension and turbidity throughout the water column. The current technical solution is to use dredging curtains that seek to contain turbidity and dispersion in the work area, but that in no case reduce this impact. As of the 19th century, suction pumps began to be used in dredging operations.

The fundamental characteristic of hydraulic dredging is the use of the suction pump, and all the variants of these equipments derive in the way of transporting the product, the use of complementary equipment for the disintegration of the land and the way of facilitating the absorption of the products by the current produced by the pumps.

A suction dredger in progress is a self-propelled and self-propelled vessel, of variable dimensions, designed to dredge continuously high volumes of material in a simple and economical way, and admitting adverse maritime conditions.

The material is aspirated by a tube provided at its end with a suction head. A pump is installed on board the boat that creates the necessary vacuum in the head to suspend the loose materials in the water, and the water-material mixture that is stored in the dredge's own tank is sucked.

During the dredging process, the ship is still moving, although at a much lower speed than the cruise. The aspirated material is poured into a pitcher, where the solids decant towards the bottom and the water that remains above is evacuated through an overflow device. What is dredged is a mixture of water and solids, such as sand.

Since the main objective of dredging is to collect the greatest amount of solids for reuse or deposition at another point, the dredger must have a system that maximizes the retention of these dredged solid materials and minimizes the amount of water left in the sing. Excess water must be separated and returned to the sea. The solid part or the remaining sediment will be deposited at the bottom of the pitcher, but this process takes time. An overflow system offers the means to separate solids from water by reducing the turbulence of the mixture and allowing sufficient time for the solid part (sand, gravel) to settle to the bottom. Then, the water is separated and this excess is returned to the sea.

For its part, the choice of the dredging head will depend on the type of material to be dredged, there is a wide range of possibilities that range from simple extension of the pipe to more complex elements to which auxiliary elements are incorporated to favor suspension or Disintegration of sediment at the bottom and increase pulp density. The head has some freedom of movement in the vertical plane, so that it can adapt to the layer of ground to be dredged.

The main deficiency of suction dredgers is that the dredging head is attached to the vessel by means of an arm, which in operation transmits to the head the movements of the ship due to the waves. Due to this, the head can suffer oscillations that cause it to lose contact with the bed, increasing the proportion of water in the aspirated material and reducing the dredging efficiency; or that it is "buried" in the bed, so that it not only loses efficiency, but also generates additional turbidity and can even lead to a mechanical breakdown due to the efforts generated on the arm.

In an attempt to prevent the movements due to waves from being transmitted to the head, the arms of the dredgers have joints. The most modern dredgers even have more complex systems. One of them is known as "wave compensator", which by means of automatic motorized equipment tries to compensate for such movements. Said system in particular is a team that has a considerably high cost and whose efficiency, according to the experience of the dredge operators themselves, is quite limited.

On the other hand, there are also stationary suction dredgers, which dredge anchored at one point, without moving while the suction occurs. This type of dredge has a great similarity with the dredging dredgers in progress, although the main difference lies in the process of loading the material. In general, stationary suction dredges do not incorporate a pitcher, and transport is carried out by auxiliary gangsters or through pipes if the discharge zone is close to the extraction zone.

The cutter dredgers or “ cutter” are a direct improvement of the stationary suction dredger, which also incorporates a ground-breaking device mounted at the end of the suction tube. The cutting head allows to work on more cohesive materials and with a superior resistance to cutting than those allowed with the rest of hydraulic dredgers. The system is placed on a pontoon without propulsion capacity that has a dredging scale at one of its ends. The cutting head is undoubtedly the singular element of this type of dredgers, in some cases creating new types of cutting dredgers, with specific names, which are used in singular works.

Patent ES2161326 (T3), refers to dredging with a suction head assisted by a ship that includes propulsion means to move in a direction transverse to its longitudinal axis. The use of winches is proposed to suspend the discharge head and tube, to lower, raise and even move them parallel to the longitudinal axis of the ship. However, there is no teaching that allows or suggests avoiding transmitting the effect of the swell to the head.

In ES2337897, a dredging vessel connected by a tube to a drag head is disclosed. The head has means for cutting the bottom of a body of water, which allow at least one stream of water to be directed towards the bottom. Therefore, improvements to a common suction head are taught, however, there is no teaching or suggestion regarding the loss of efficiency due to the effect of the waves transmitted to the head.

In WO / 2002 / 057551A1 aspiration of the bed material is disclosed using hydrostatic pressure difference between an intermediate floating station and the seabed, without addressing the problem of loss of efficiency due to waves or surface currents.

Through the use of suction dredgers and mechanical dredgers, dredging does not generate a homogeneous bottom, the appearance of hills and valleys being frequent, that is, areas above or below the marked elevation. This may be due, either by the effect of the swell in the case of suction dredging or by the bumping and geometry effect of buckets or backhoes in mechanical dredging. All this entails the need to review the work and poor efficiency in the dredging process.

Regarding dredging operations using submerged equipment, this is a field where there is hardly any experience, being limited at the moment to hydraulic dredging equipment for experimental development and low suction volume.

As previously mentioned, the main shortcomings of current dredging systems are:

- be subject to the effect of the waves that affect the boats, on which they depend, generating inefficiencies in the dredging system;

- not be designed taking into account the environmental factor, so they do not incorporate systems that reduce turbidity;

- they have no capacity to perform dredging tasks autonomously; - not having systems that allow continuous analysis of the dredging task.

Description of the invention

The present invention solves the problems existing in the state of the art by means of an autonomous dredging underwater equipment (ESDA) that has the capacity to move along the bottom and for the withdrawal by aspiration of materials from the seabed, well controlled by an operator or by autonomous operation and dredging procedure.

In addition, the ESDA is equipped with different sensors, to capture data that allow to know its position and analyze the environment, thanks to this information it is It is possible to predefine routes, suction power and any other parameters necessary for the ESDA to proceed to carry out dredging in automatic mode.

There is no rigid connection with other equipment or vessel that moves along the surface, eliminating the effect of the waves, therefore, the suction system does not separate from the bottom avoiding excessive water suction. In addition to the ballast of the equipment itself, a spindle or front end screw acts as a follower allowing the equipment to adapt to the bottom.

The effects achieved with this equipment also include:

- reach a greater sweeping width, than that of the head's own suction mouth, by means of the front spindle, regardless of the type of dredging carried out;

- eliminate the hitting effect on the bottom, avoiding overdrafts;

- limit turbidity in the lower layer of the water column minimizing its impact and dispersion of pollutants, thanks to the suction of the equipment itself and the "bell" that form the frame and drive system;

- allow continuous dredging monitoring, through the use of image capture, dynamic positioning and data transmission equipment.

The present vehicle or Submerged Autonomous Dredging Equipment (ESDA) consists of a system with capacity to move along the bed and dredge it by suction. For its operation, it needs the support of a surface unit, either floating (pontoon, dredger or other similar) or arranged on land, that performs functions such as collecting dredged material and powering the systems it includes electrically and hydraulically.

The team is formed by a rack that supports the different subsystems that make up the assembly.

Given the irregularity of the funds, and since the ESDA is designed for dredging of different types of materials, it incorporates a driving system with wheels on which caterpillars can be mounted and allow its movement through the bed in adverse conditions and on various surfaces .

To dredge, it has a dredging unit that replicates a drag dredge. The pumping system of this equipment can be installed either on the surface support unit or directly on the head or dredging unit carried by the ESDA.

The dredging unit is connected to the frame by means of an arm that allows the necessary degrees of freedom so that it remains at all times in contact with the bed, maximizing the efficiency in aspiration. Precisely, this is one of the biggest advantages of the proposed system over conventional dredging systems. The proposed equipment moves in contact with the bed, so keeping the head on the bottom is much simpler and therefore efficient.

The equipment has an endless screw, mounted on its front part, which removes the material from the bed and leads it to the central suction area. In this way a greater compaction of the dredged material and a smaller amount of suction of drag water is achieved. With this function, dredging efficiency is improved by increasing the proportion of solid material against water, reducing operating times. Optionally, the dredging unit may incorporate mechanical equipment to remove the material from the bed prior to dredging. Another alternative, of means for removing material, comprises a system of injection of liquid under pressure projected from a pipe arranged at the periphery of the head with a plurality of nozzles oriented towards the bed.

The dredging head will be mounted in the central area of the ESDA, so that the set formed by the caterpillars and the frame constitute a kind of bell that helps contain the turbidity that is generated during displacement and dredging. In any case, the whole set will be designed taking into account this premise, incorporating, for example, other perimeter closure elements, so that the turbidity generated is contained as far as possible.

The ESDA has a pipe through which it connects with the surface support unit to raise the material from the dredging. The length of the pipe in combination with the dredging depth will condition the radius of action of the ESDA with respect to the surface support unit. This pipe is equipped with flotation, so that the remaining length remains on the surface around the support unit and does not drag along the bed, since if so It would cause turbidity, the already dredged bed would be modified and could interfere with the ESDA in its work trajectory. The equipment that integrates the ESDA, hydraulic, electrical and pneumatic, as appropriate, will be fed from the surface support unit, so that along with the pipe the necessary hoses will be lowered to feed them. For its part, the necessary devices will be included in the frame to be able to be lifted to the support unit or taken out of the water by means of a crane (or gantry).

The ESDA has a system that allows its movement both guided at all times by an operator, and in autonomous mode according to a predefined route during dredging planning operations, such that the dredging operator will only have to do the supervision and move on to manual mode in case of any incident. Thus, an automatic pilot mode on cartography and guidance and positioning by acoustic or similar systems will be included.

Brief description of the drawings

Next, to facilitate the understanding of the invention, an illustrative but non-limiting way will describe an embodiment of the invention that refers to a series of figures.

Figure 1 shows a perspective view of the ESDA Autonomous Dredging Submarine Equipment with the necessary systems for its operation.

Figure 2 (A) shows a side view of the dredging equipment before starting to pump sediment in which the head is separated from the seabed; and Figure 2 (B) shows the dredging head at the maximum dredging depth after a continuous approach. In both representations, the concentrator system appears in its lowest position, which coincides with the maximum dredging depth. In addition, a floating support unit, particularly a pontoon, is represented at the top, which is an integral part of dredging tasks.

Figure 3 shows perspective views of two embodiments of the dredging unit, in (A) it is presented with a head devoid of drive and in (B) incorporating the pumping system with a pump, in both cases the protection of the dredging unit, all forming a single set.

Figures 4 (A) and (B) show two perspective views from the front or the aspiration of the dredging unit in correspondence with the embodiments of Figures 3 (A) and (B).

Figure 5 shows another modality of the dredging unit, which allows varying the pumping angle: (A) isometric view, (B) side view with the suction nozzle of the inclined pump, and (C) side view with the suction nozzle horizontal.

Figures 6 (A), (B) and (C), show different stages of the draw of an obstacle made by the concentrator and the dredging unit.

These figures represent the functional elements of the autonomous dredging underwater equipment and the dredging procedure, identifying the following numbering:

1. Frame

2. Drive system

3. Dredging unit / dredging head

4. Concentrator

5. Seabed

6. Maximum dredging depth

7. Pump protection

8. Surface support unit

9. Means for adjusting the pumping angle

Detailed description of the invention

The movement of the equipment of figure 1 along the seabed (5) is carried out by means of a drive system (2) consisting of tracks mounted on four driving wheels fixed to the frame (1). In this way the contact surface is increased, which guarantees the correct displacement of the assembly on the sedimentary bed. The independent operation of each group of wheels allows turning with a small radius.

Once the vehicle is located in the area to be dredged (figure 2A), the concentrator (4) descends to the maximum dredging depth (6) and the worm begins to rotate in a favorable direction to the progress of the assembly by removing and stacking or gathering the bed material in the central area, between the caterpillars and near the mouth pump suction. As the worm sweeps a width greater than that of the suction nozzle, it is possible to increase the surface dredged in each pass.

Figures 2A and 2B illustrate the operation of the dredging unit (3), which is initially at a height above the seabed (5) and then a progressive and controlled approach is made until reaching the maximum depth of dredged (6). This operation guarantees the correct priming of the suction process and prevents the obstruction of the dredging unit due to excess material density. Likewise, during the work regime, the density of dredged material can be decreased by increasing said height, pumping a greater percentage of water. In any case, obstructions by solid materials of a larger diameter than the one admitted are not possible, since at the entrance of the dredging unit there is a particle filter that prevents solids from entering the dredging unit from entering. During the movement of the dredging unit (3) the angle between the suction mouth of the dredging unit and the bed (5) is maintained so that the process efficiency is guaranteed.

Since in the bed there is rarely homogeneity of materials, with a mixture of sludge, sand of different grains, stones, etc .; and that the equipment will be used in areas with different predominant material (areas where sand predominates or areas where mud predominates), the equipment must be versatile in terms of dredging capacity. More compact materials will require a longer suction time at each point, so the vehicle's forward speed will be lower, and the pumping angle closest to horizontality can be maintained; on the other hand, when the speed is advanced, the inclination of the dredge of the dredging equipment improves the material input.

As previously proposed, a fixed dredging angle allows to search for efficiency by controlling the movement of the equipment. Optionally, the control of the pumping angle can be incorporated, for example, by means of hydraulic regulation controlled in an integrated manner with the displacement. An exemplary embodiment is presented in Figures 5A-5C, where the means for adjusting the pumping angle (9) allow the pumping angle to be varied from an inclined position, Figure 5B, at a horizontal position of the suction mouth, Figure 5C. The foregoing does not exclude the use of alternative methods of the state of the art to vary this angle in a controlled manner.

The elements necessary to avoid dispersion of turbidity beyond the ESDA operating area are the structure of the drive system (2) and the frame (1), which confine the dredging unit (3) to a central area or inside the equipment, in addition to the dredge pump itself.

The dredging unit (3), as shown in detail in Figure 3 and in operation in Figures 6A-6C, has a protection (7) against possible obstacles that may be encountered during the advance, a similar protection is incorporated into the concentrator (4). Both sets are arranged to articulate, adapting their geometry to the obstacle so that their main parts are protected from possible blows. As illustrated in Figures 6A and 6B on contact with an obstacle, the grid-shaped frame articulates the concentrator (4) upwards, protecting the rotation of the worm; similarly, in figure 6C the protection (7) facilitates the lifting of the dredging unit (3), protecting its integrity.

The Autonomous Dredging Submarine Team presents at all times the assistance a surface support unit (8) either floating (pontoon or dredge) or installed on land that receives the sedimentary material pumped from the bottom through the pipe connected in the discharge of the pumping system.

The gathering of the environment information and the autonomous vehicle route plan are tasks performed by the Dredging Supervision and Control Team (ESCD); This supervisory team consists of:

a) Image capture equipment, dynamic positioning and data transmission / reception, installed on ESDA itself.

b) Software for the analysis and calculation of routes, positioning systems and data transmission / reception installed in the surface control center.

For further illustration of the invention, in order to solve the technical problem raised, a preferred embodiment presents a submerged autonomous dredging equipment (ESDA) to move along the bed and dredge it, mitigating the environmental impact of its operation, which works in cooperation with a surface support unit, either floating or on land, that performs functions such as collecting a dredged material, powering the equipment electrically and hydraulically and providing a means of communication to supervision and / or control.

The team includes:

a) a structural frame (1);

b) a drive system (2) with four drive wheels anchored to the frame (1);

c) a dredging unit (3) that is mounted to the frame (1) by an arm with sufficient degrees of freedom to allow the dredging unit to be kept in contact with the bed (5) at all times, where the dredging unit it is located in a central area of the equipment so that the assembly formed by the frame (1) and the drive system (2) constitute a bell around it to contain the turbidity generated during displacement and dredging;

d) a concentrator (4) pivotally mounted on the front part of the frame (1), consisting of an endless screw and a support and protection structure for said endless screw arranged to remove and gather material from the bed in the central zone;

e) a guidance system that allows both remote controlled travel by an operator, and in autonomous mode according to a predefined route; Y

f) a flexible pipe to raise the dredged material to the surface support unit, and to guide conductors and hoses to feed the equipment.

The equipment also includes a limit for the descent of the concentrator (4) establishing the penetration capacity in the material to be dredged.

In a particular embodiment the dredging unit (3) includes a pump, on the ESDA and the worm of the concentrator (4) sweeps a width greater than that of the suction nozzle of the pump. In another embodiment it comprises a system of Pumping that is installed on the surface support unit to provide suction capacity to the dredging unit (3).

In other aspects of the invention the pipe is provided with flotation and the frame (1) includes devices for lifting the equipment to the support unit.

In addition, the autonomous mode of the guidance system includes the collection of environmental information and the route plan of the autonomous vehicle that are tasks performed by a supervisory team consisting of:

a) image capture, dynamic positioning and data transmission / reception equipment installed on the equipment; Y

b) software for the analysis and calculation of routes, positioning systems and data transmission / reception installed in the surface control center.

The equipment optionally includes tracks mounted on the four driving wheels.

Optionally, the equipment comprises means for regulating the hydraulic drive pumping angle (9) arranged in the dredging unit (3).

Similarly, the dredging procedure by a submerged autonomous dredging equipment presented here comprises the steps of:

a) lower the equipment from the surface support unit to a bed (5);

b) release a concentrator (4) to swing down to its lowest position in contact with the bed (5);

c) starting the pump of the pumping system (3);

d) initiate the movement of the equipment through the bed (5) either in autonomous mode or controlled by operator;

e) initiate a continuous approximation of the dredging unit (3) until reaching the maximum dredging depth defined by the position of the concentrator (4); Y

f) raise the dredged material through a flexible pipe to the surface support unit.

Optionally, during step e) the pumping angle is varied in a controlled manner.

Application examples

Example 1.

In a particular case of the equipment that works assisted by a pontoon on the surface, and incorporates a dredging unit with its own drive (figures 3B and 4B), the dredging unit pump has a suction nozzle of 400 mm diameter and the Hub spindle sweeps a width of one meter. But these measures are those of a specific case; As the demands on the equipment grow, the dimensions do too.

As mentioned earlier, the higher the speed of movement of the equipment, the inclination of the suction nozzle of the pump with respect to the bed improves the entry of material. The combination possibilities acting on the different parameters, will allow to find the optimal ones for the different types of materials and beds. As an example, the proposed design range is 0-25 °; For the purposes of this request, no upper limit is established for this inclination.

The suction head is mounted to the frame (1) by means of an arm that allows mainly vertical displacements, with minimal variations in the inclination of the pump with respect to the bed, for example, a four-bar mechanism.

The maximum estimated depth for dredging is 30 meters, without this being a limitation for other greater depths.

Example 2

For this second example, the ESDA with dredging head and surface pumps is presented on board a dredge type suction boat. The measurements are subject to the same criteria of the previous example, the measurements may vary as required. The drive system consists of four wheels and plates are provided that cover the sides between the wheels, to provide the effect of a turbidity control bell.

To eliminate the need for a diver to lower the ESDA mooring to the crane boom, it is possible to incorporate positive flotation systems such as ballast tanks and balloons

Claims (11)

1. A submerged autonomous dredging equipment (ESDA) to move along the bed and dredge it by suction, mitigating the environmental impact of its operation, which works in cooperation with a surface support unit, either floating or on land, which performs functions such as collecting a dredged material, powering the equipment electrically and hydraulically and providing communication means for supervision and / or control, characterized in that it comprises: a) a structural frame (1); b) a drive system (2) with four drive wheels anchored to the frame; c) a dredging unit (3) that is mounted to the frame (1) by an arm that mainly allows vertical displacements, where the dredging unit is located in a central area of the equipment so that the assembly formed by the frame (1) and the drive system (2) constitute a bell around it to contain the turbidity generated during displacement and dredging; d) a concentrator (4) pivotally mounted on the front part of the frame (1), consisting of an endless screw and a support and protection structure for said endless screw arranged to remove and gather material from the bed in the central zone; e) a guidance system that allows both remote controlled travel by an operator, and in autonomous mode according to a predefined route; Y f) a flexible pipe to raise the dredged material to the surface support unit, and conductors and hoses to power the equipment electrically and hydraulically. 2. The submerged autonomous dredging equipment according to claim 1, characterized in that it further comprises a limit for the descent of the concentrator (4) by establishing the penetration capacity in the material to be dredged. The submerged autonomous dredging equipment according to claim 1, characterized in that the dredging unit (3) includes a pump, on the ESDA and the worm of the concentrator (4) sweeps a width greater than that of the suction nozzle of the bomb. The submerged autonomous dredging equipment according to claim 1, characterized in that it comprises a pumping system that is installed on the surface support unit to provide suction capacity to the dredging unit (3). 5. The submerged autonomous dredging equipment according to claim 1, characterized in that the flexible pipe is provided with flotation. The submerged autonomous dredging equipment according to claim 1, characterized in that the frame (1) includes devices for lifting the equipment to the support unit. 7. The submerged autonomous dredging equipment according to claim 1, characterized in that the autonomous mode of the guidance system comprises the gathering of the environment information and the route plan of the autonomous vehicle which are tasks performed by a supervisory team that is formed by: a) image capture, dynamic positioning and data transmission / reception equipment installed on the equipment; Y b) software for the analysis and calculation of routes, positioning systems and data transmission / reception installed in the surface control center. 8. The submerged autonomous dredging equipment according to claim 1, characterized in that it comprises tracks mounted on the four driving wheels. 9. The submerged autonomous dredging equipment according to claim 1, characterized in that it comprises means for regulating the hydraulic actuating pumping angle (9) arranged in the dredging unit (3). 10. Dredging procedure by submerged autonomous dredging equipment arranged to move along the bed and dredge by suction, mitigating the environmental impact of its operation, which works in cooperation with a surface support unit that performs functions such as collecting a dredged material, powering the equipment electrically and hydraulically, and providing communication means for supervision and / or control, characterized in that it comprises The steps of: a) lower the equipment from the surface support unit to a bed (5); b) release a concentrator (4) to swing down to its lowest position in contact with the bed (5); c) starting the pump of the pumping system (3); d) initiate the movement of the equipment through the bed (5) either in autonomous mode or controlled by operator; e) initiate a continuous approximation of the dredging unit (3) until reaching the maximum dredging depth defined by the position of the concentrator (4); Y f) raise the dredged material through a flexible pipe to the surface support unit. 11. Dredging method according to claim 10, characterized in that during the step e) the pumping angle is varied in a controlled manner