NL2017021B1

NL2017021B1 - Seaweed harvester

Info

Publication number: NL2017021B1
Application number: NL2017021A
Authority: NL
Inventors: Sijl Jochem; Bernardete Gonçalves Castro Maria; Gerard Van De Ketterij Robert; Ketting Yarno; Heinrich Brandemann Christian
Original assignee: Ihc Holland Ie Bv
Priority date: 2016-06-21
Filing date: 2016-06-21
Publication date: 2018-01-04
Also published as: CN109310058A; BR112018076733A2; WO2017222373A1; JP2019520072A; EP3471533A1

Abstract

The present invention therefore seeks to provide a seaweed harvesting system for collecting seaweed comprising: - an intake section for taking a seaweed substrate for growing seedlings and/or seaweed at the waterline, - a transport device for transporting the substrate in a transport direction from the intake section through the harvesting system, - a cutting device for cutting the seaweed from the substrate, wherein the cutting device comprises a pre-tensioning system to control a cutting force applied to the substrate.

Description

Seaweed harvester

Field of the invention

The present invention relates to a seaweed harvesting system, vessel comprising such a seaweed harvesting system, a seaweed cultivation system and a coupling device for coupling substrates for seaweed.

Background art

Cultivated seaweeds are typically harvested manually. Fully mechanical harvesting has typically only been done on naturally growing seaweed types that grow at the sea bottom. As the seaweed grows on the seafloor, the harvesting is done with a rake and crane. Though there have been some devices developed for assisting in the cultivation and harvesting process of seaweeds, most work involves heavy and risky human labour. One such device can be found in WO2013/022336, which discloses a device with a line for retaining seaweed in a plurality of rows, a holder for holding the seaweed in a fixed place along the line and a vessel for harvesting. The vessel can be a traditional boat used by local fisherman. The vessel has a reaper, and during harvesting, one line is pulled over the reaper where hanging seaweed from the holder will be cut by the reaper and fall into the waiting vessel. Other devices for harvesting also typically include some sort of system to pull a rope with seaweed to a surface or a vessel for cutting and harvesting the seaweed. Such systems can be found in KR20120010440 and CN103069966. While some of these devices and systems are semi-automatic, each require a considerable amount of human labour.

Important is that the quality of seaweed deteriorates rapidly during the harvesting season, and one may need to harvest a large field within a few days, to guarantee maximum and uniform product quality, similarly to agricultural crops. When cultivating larger fields, (typically more than 2-5 hectare) massive labour costs are involved to harvest the seaweed within the desired window of time. This makes the large scale farming not viable in world regions where human labour is costly. In conclusion, the state of the art has the following problems. Cultivated seaweeds are typically harvested manually, which results in large and heavy labour. Additionally, the harvesting is done using small fishing vessels with minor adaptations that still require much human labour. Further, the cutting of some types of seaweed requires a better cutting process than reaping. Currently, this is done manually using knifes. No fully mechanical harvesting devices for seaweed cultivation currently exist, especially for coastal areas with swell and waves. Fully grown seaweed must be harvested in a limited amount of time -in a similar way to land harvesting- . Using existing technology, this requires prohibitive labour costs for large farms of more than a few hectares.

Summary of the invention

The invention aims to provide a seaweed harvesting system that is seaworthy, requires minimal labour and is able to harvest seaweed fast.

Another object of the invention is to improve existing seaweed harvesting systems in that a problem associated therewith is at least partly solved.

Yet another object of the invention is to provide an alternative seaweed harvesting system.

This enables a continuous and automated process wherein both seaweed and the seaweed substrate are removed from the water in a continuous way. The process is much faster than manual harvesting. There is no need for human labour on the heavy and dangerous conditions of working on at sea.

According to the present invention, a seaweed harvesting system as defined above is provided, wherein the transport device comprises spaced apart guiding means for aligning the substrate and the harvesting system. This alignment avoids mechanical tension in the substrate or any other transport lines.

According to the present invention, a seaweed harvesting system as defined above is provided, in which the harvesting device comprises a washing device for washing seaweed while the substrate is transported through the washing device.

In general washing the seaweed can be needed before final use. Washing of the seaweed is enabled during harvesting.

According to the present invention, a seaweed harvesting system as defined above is provided, in which the washing device is arranged upstream with respect to the cutting device. Washing of the seaweed while attached to the substrate gives much better control of the washing and dripping process.

According to the present invention, a seaweed harvesting system as defined above is provided, wherein the intake device comprises a guiding member proximate the waterline for guiding the substrate along the transport direction. This way, the seaweed substrates can enter and be guided into the harvesting system gently, even when the currents are strong.

According to the present invention, a seaweed harvesting system as defined above is provided, comprising substrate guiding means to hold the substrate above the waterline. This ensures that the seaweed substrate is maintained within the harvesting device. The seaweed is guided to a final storage location.

According to the present invention, a seaweed harvesting system as defined above is provided, comprising a collecting device arranged downstream the cutting device for collecting cut seaweed into a seaweed container. The seaweed container acts as temporary a buffer so that e.g. compacting and packaging of seaweed is decoupled from the cutting device and the transport device and can be done independently.

According to the present invention, a seaweed harvesting system as defined above is provided, comprising a compacting unit to compact cut seaweed. Freshly harvested seaweed takes much space. Compacting may reduce the volume up to 50% of the original.

According to the present invention, a seaweed harvesting system as defined above is provided, wherein the transport device comprises a first endless conveyor belt arranged downstream and adjacent to the intake section, and wherein the first endless conveyor belt makes an angle a of between 30°- 90° with respect to the horizontal, preferably between 30°- 60°, more preferably between 35°- 45°.

The conveyor belt making the angle a with the horizontal waterline, lifts the seaweed substrate gently from the water, and at the same time excess salt water can flow downwards back to the sea. Moreover, by having the specific angle with respect to the horizontal, the conveyor belt can easily carry all the heavily grown seaweed of the intake section, with a minimal friction of the intake section and other mechanical parts within the system that could cause wear and tear of said intake section. In this manner, the intake section will have an extended longevity and better performance.

According to the present invention, a seaweed harvesting system as defined above is provided, comprising a mooring system to securely connect the harvesting system to the sea bed, wherein the mooring system comprises a damping system. Limiting the mechanical tension and stress in the substrate is important. The mooring system comprising a damping system contributes to control of the mechanical tension and stress in the substrate.

According to the present invention, a seaweed harvesting system as defined above is provided, comprising a buoyancy control unit to allow the harvesting system to be lowered below the waterline. Active control of buoyancy and flotation is useful in offshore conditions. The harvesting system can be lowered under water. It will be understood that the default situation of the harvesting system will be floating. If circumstances require so, like rough sea conditions, the harvesting system can be lowered to a safe depth below the waterline and can be recovered later.

According to the present invention, a seaweed harvesting system as defined above is provided, comprising a winch arrangement for coupling the harvesting system to a transport line. By using the winch arrangement, it allows for the harvester system to “seed” that is to say launching the freshly planted substrate into the water. The winch arrangement may also contribute to transport of the substrate through the harvesting system during harvesting.

The invention further relates to a vessel comprising a seaweed harvesting system as defined above.

The invention further relates to a seaweed cultivation system comprising a harvesting system as defined above, wherein the seaweed cultivation system comprises: - a first and a second floater connected to an anchoring element, and - a displacement system provided at a position in between the first and second floater such that a seaweed substrate of seedlings and/or seaweed is connected to the first and second floaters, wherein each of the floaters is securely connected to the seabed by a mooring system comprising an damping system, preferably an active damping system, and wherein the substrate is at least partly accommodated within the harvesting system to harvest the seaweed. This enables a continuous and automated process wherein both seaweed and the seaweed substrate are removed from the water in a continuous way. The process is much faster than manual harvesting. There is no need for human labour on the heavy and dangerous conditions of working on at sea. In addition, the first and second floaters enable to control the mechanical tension in the substrate and the depth of the substrate with respect to the waterline.

It will be clear that a number of seaweed substrates may be connected to the first and second floaters. Such substrates may take the form of for example a line, a netting or ribbons. Handling of multiple substrates simultaneously increases productivity. There is a given limit to the speed at which a seaweed substrate can be pulled from the water, beyond that speed, seaweed will detach from the substrate or be damaged.

According to the present invention, a seaweed cultivation system as defined above is provided, wherein the displacement system comprises: a winch connected to the first floater; a pulley connected to the second floater; and a line extending from the winch around the pulley and to the harvesting system; wherein the winch is able to wind or unwind the line to move the harvesting system between the first and the second floater. It is conceivable that the line is connected to the harvesting system through a floating bracket. This facilitates connecting of the line to the harvesting system and recovery of the line if required.

According to the present invention, a seaweed cultivation system as defined above is provided, wherein the displacement system further comprises a stretcher connected to the first floater for tensioning the substrate, or if applicable a number of substrates simultaneously. The stretcher keeps the substrate(s) under tension, and solves the problem of rupture of substrates.

According to the present invention, a seaweed cultivation system as defined above is provided, wherein a fast coupling device is provided on the first floater for connecting and locking the substrate with the cultivation system. Use of a fast and robust seaworthy locking device will speed up seeding and harvesting. In the art connecting of a substrate to a floater or to another substrate section is currently done by knots. This takes too much time and in addition, knots do not runs smoothly over a pulley. As a background, the substrate may typically have a length of 50 meter. If one wants have a bigger cultivation system, substrate sections need to be connected to one another.

According to the present invention, a seaweed cultivation system as defined above is provided, wherein an active floating member is provided to actively submerge the first floater and/or the second floater by adding or removing fluid to a fluid tank connected to the first and second floater, and a control device to control the submersion and flotation.

As explained in connection with the harvesting system, this active control of flotation is useful in offshore conditions. The whole cultivation system, or in other words farm, can be lowered under water. Preferably, fluid is transferred between tanks that are closed from the outside environment, this eliminates the contact with sea water which otherwise may cause trouble.

Short description of drawings

The present invention will be discussed in more detail below, with reference to the attached drawings, in which fig. 1 shows in perspective view a harvesting system according to the invention, fig. 2 is a schematic view of a detail of a harvesting system in that a first embodiment of a cutting device is shown, fig. 3a, 3b is a detail of a harvesting system wherein a second embodiment of a cutting device is shown in two states, fig. 4a, 4b is a detail of a harvesting system in that transport device is shown and a first (4a) and second (4b) embodiment of a cutting device, fig. 5a, 5b schematically shows a side view of a cultivation system in default (5a) and submerged state (5b), fig. 6a, 6b details of the cultivation system regarding mooring and buoyancy, fig. 7, 7a, 7b show a fast coupling device for coupling a seaweed substrate, and fig. 8 a coupling device slung around a pulley.

Description of embodiments

Fig. 1 shows in perspective view a seaweed harvesting system 1 according to the invention. In this case, the harvesting system is arranged on a vessel 12. The seaweed harvesting system 1 is designed for collecting seaweed out of the sea.

The harvesting system comprises an intake section 3 for taking a seaweed substrate 13 for growing seedlings and/or seaweed at the waterline. Here, the intake section 3 is V - shaped and guides the substrate 13 into the harvesting system 1. In other words, the harvesting system 1 has guiding means 13 for aligning the substrate 13 and the harvesting system 1. Here, the substrate 13 is in the form of a line or rope.

The harvesting system 1 comprises a transport device 2 for transporting the substrate in a transport direction from the intake section 3 through the harvesting system 1.

The harvesting device 1 comprises a washing device 5 for washing seaweed while the substrate 13 is transported through the washing device 5.

The harvesting system 1 comprises a cutting device 7 for cutting the seaweed from the substrate 13. Here, the washing device 5 is arranged upstream with respect to the cutting device 7.

The harvesting system 1 comprises a collecting device 11 in the form of a container arranged downstream the cutting device 7 for collecting cut seaweed.

The harvesting system 1 comprises a compacting unit 9 to compact cut seaweed. Freshly harvested seaweed takes much space. Compacting may reduce the volume up to 50% of the original.

Here, the transport device comprises a first endless conveyor belt arranged downstream and adjacent to the intake section 3. The first endless conveyor belt makes an angle a of between 30°- 90° with respect to the horizontal, preferably between 30°- 60°, more preferably between 35°-45°.

The harvesting system 1 comprises a mooring system (not shown) to securely connect the harvesting system 1 to the sea bed. The mooring system comprises a damping system. The seaweed harvesting system comprises a buoyancy control unit (not shown) to allow the harvesting system 1 to be lowered below the waterline.

The harvesting system 1 comprises a winch arrangement 6 for coupling the harvesting system to a transport line 13 which here also functions as a substrate.

The harvesting system 1 is placed on a vessel, here a pontoon. As an option, the harvesting system 1 is containerizable.

Fig. 2 shows a schematic view of a detail of a harvesting system in that a first embodiment of a cutting device 7 is shown. The cutting device 7 cuts seaweed 14 from the substrate 13. The cutting device 7 comprises a pre-tensioning system in the form of a spring 16 to control a cutting force Fc (not shown) applied to the substrate 13, here a line. The substrate 13 runs between a pair of knifes 15a, 15b. The knives 15a, 15b have a circular shape with a cutting edge at their outer circumference. The knives 15a, 15b are rotatably arranged. The axis of rotation of the knives 15a, 15b is transverse with respect to the transport direction of the substrate 13.

Fig. 3a, 3b is a detail of a harvesting system wherein a second embodiment of a cutting device 7 is shown in two states. The knife 17b has an elongate shape and has a cutting edge at its leading side that is the side facing approaching seaweed 14. The presence of an additional knife 17b is conceivable. Here an opposite knife 17a is provided. The substrate 13 runs between the knives 17a, 17b. The cutting force is controlled by means of a spring 16 and a wedge arrangement 18 slideably coupled with the knife 17b.

The skilled person will appreciate that the pre-tensioning system 16, which is embodied in the form of a spring element 16 could also be a different elastic element deformable by pressure applied in the direction generally along an axis extending between the first and second ends of said element, a pneumatic element or the like.

Fig. 4a, 4b is a detail of a harvesting system 1 in that a transport device 2 is shown and a first (fig. 4a) and second (fig. 4b) embodiment of a cutting device 7. The substrate 13 is transported by the transport device 2 in the form of a conveyer belt. The belt has protrusions 19 that engage the substrate 13 for transporting the substrate 13. The protrusions 19 extend into the meshes of the substrate 13 that has the form of a netting. The cutting device 7 has an elongate knife that extends transverse with respect to the transport device 2. The elongate knife makes an angle of about 45° with respect to the transport direction. As a result, the cut seaweed 14 is forced onto a transverse conveyer 8. Fig 4b has a series of pair of knifes as shown in fig. 2 as a cutting device 7. fig. 5a, 5b schematically shows a side view of a cultivation system 26 in default (fig. 5a) and submerged state (fig. 5b). The seaweed cultivation system 26 comprising a harvesting system as described above, however not shown here. The seaweed cultivation system 26 comprises a first and a second floater 21a, 21b. The first and a second floater 21a, 21b are connected to an anchoring element 201,20b. Each floater 21 may have a respective anchoring element 20 as shown in fig 5a, or anchoring elements 20 that have an anchoring point in common as shown in fig. 6b.

The seaweed cultivation system 26 comprises a displacement system that may drive a harvesting system and/or floaters 21 when required. The displacement system is provided at a position in between the first 21a and second floater 21b such that a seaweed substrate 24 of seedlings and/or seaweed is connected to the first and second floaters. Each of the floaters 21a, 21b is securely connected to the seabed by a mooring system 20a, 20b comprising a damping system, preferably an active damping system.

The substrate 24, here a line, is at least partly accommodated within the harvesting system to harvest the seaweed. The first and second floaters 20a, 20b enable to control the mechanical tension in the substrate 24 and the depth of the substrate 24 with respect to the waterline 22.

The displacement system comprises a winch 23 connected to the first floater 21a. The displacement system comprises a pulley 25 connected to the second floater 21b. The displacement system comprises a line 24 extending from the winch 23 around the pulley 25 and to the harvesting system. It is conceivable that the line 24 is connected to the second floater and/or the harvesting system. The winch 23 is able to wind or unwind the line 24 to move the harvesting system between the first 21a and the second 21b floater. It is conceivable that the harvesting system is connected to the harvesting system through a floating bracket. The line 24 may be a separate transport line and/or a line that also functions as a substrate. The displacement system further comprises a stretcher (not shown) connected to the first floater 21a for tensioning the substrate 24.

Fig. 6a, 6b show details of the cultivation system regarding mooring and buoyancy. Fluid may be pumped between containers to raise or lower a mooring system and/or a floater 21. In fig. 6b the anchoring elements 20 a-c have an anchoring point in common that is here, the floater 21 with a buoyancy control system.

Fig. 7, 7a, 7b show a fast coupling device 27 for coupling a seaweed substrate 28. In fig. 8 the coupling device 27 is slung around a pulley 43 and couples substrate sections 13.

The fast coupling device 27 solves a problem in that existing locking devices are not seaworthy enough for underwater applications, or the cross section of existing coupling devices is too large compared to the line diameter. Another problem with existing couplings is they are too stiff to run around a pulley. Also seamen knots to connect ropes and other elements in seaweed farms are not suitable for running through pulleys of the harvesting device.

The fast coupling device 27 has a limited outer diameter. The coupling device 27 is seaworthy and can be locked in a few seconds, or even with the use of machines in case the ropelike structures are heavy and large. Seaworthiness of the coupling device 27 is ensured by the locking sequence and by the choice of materials. Further the fast-coupling device is made of flexible material that allows the coupling 27 to follow guides and pulleys even with tight turning radius, even in the situation when the turning hook in the transport is smaller than 90°, see fig. 8.

The coupling has two main elements, a male portion left in fig. 7 and a female portion right in fig. 7. The male portion and the female portion are coupled by a twistlock arrangement 32, 33a, 35b. Additionally, the male portion and the female portion are coupled trough a threaded connection 40, 41, 42. This double connection ensures a secure coupling while maintaining a small outer diameter. A loose line or rope end is provided with a cone shape, or here a double cone. A closing ring 36 slides along a respective housing 37, 38 that accommodates a loose line end and a cone shape in order to secure the loose end to a respective housing 37, 38 by wedging. The two housings 37, 38 then connect through the twistlock arrangement 32, 33a, 35b. The twistlock arrangement 32, 33a, 35b comprises a rectangular locking element 32. This element 32 is introduced into the female portion, and then twisted. Upon twisting the element 32, stop faces 33a and 35b abut. A spring exerts a force onto the element 32 that forces the stop faces 33a and 35b into engagement. The twistlock typically needs a turn of about 90°. In an alternative embodiment, the coupling is finalized by a screw connection. The male portion and the female portion are provided with external threading 40, 41 and a sleeve is provided with internal threading 42.

The present invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims.

Claims

A seaweed harvesting system for collecting seaweed, comprising: - an intake section for taking in a seaweed substrate for growing seedlings and / or seaweed at the water line, - a transport device for transporting the substrate in a transport direction from the intake section through the harvesting system, - a cutting device for cutting the seaweed from the substrate, the cutting device comprising a pre-tensioning system for controlling a cutting force applied to the substrate.

The seaweed harvesting system according to claim 1, wherein the transport device comprises spaced apart guide means for aligning the substrate and the harvesting system.

The seaweed harvesting system according to claim 1 or 2, comprising a washing device for washing seaweed while the substrate is being transported through the washing device.

The seaweed harvesting system according to claim 3, wherein the washing device is arranged upstream with respect to the cutting device.

The seaweed harvesting system according to any of claims 1-4, wherein the intake device comprises a guide member near the water line for guiding the substrate along the conveying direction.

The seaweed harvesting system according to any one of the preceding claims, comprising substrate guiding means to keep the substrate above water.

The seaweed harvesting system according to any one of the preceding claims, comprising a collecting device downstream the cutting device for collecting sliced seaweed in a seaweed container.

The seaweed harvesting system according to claim 7, comprising a compacting unit to compact sliced seaweed.

The seaweed harvesting system according to any one of the preceding claims, wherein the conveying device comprises a first endless conveyor belt downstream with respect to and near the intake section and wherein the first endless conveyor belt makes an angle α between 30 ° - 90 ° with respect to the horizontal, preferably between 30 ° - 60 °, more preferably between 35 ° - 45 °.

The seaweed harvesting system according to any one of the preceding claims, comprising a mooring system for securely connecting the harvesting system to the seabed, wherein the mooring system comprises a damping system.

The seaweed harvesting system according to any one of the preceding claims, comprising a buoyancy control unit so that the harvesting system can be lowered below the waterline.

The seaweed harvesting system according to any one of the preceding claims, comprising a re-device for coupling the harvesting system to a transport line.

A vessel comprising a seaweed harvesting system according to any one of the preceding claims.

A seaweed growing system comprising a seaweed harvesting system according to any one of the preceding claims, wherein the seaweed growing system comprises: - a first and a second float connected to an anchoring element, and - a displacement system provided at a position between the first and second float such that a seaweed substrate of seedlings and / or seaweed is connected to the first and second floats, each of the floats being firmly connected to the seabed by a mooring system comprising a damping system, preferably an active damping system, and wherein the substrate is at least partially included in the harvesting system in order to harvesting seaweed.

The seaweed growing system according to claim 14, wherein the displacement system comprises: a winch connected to the first float; a pulley connected to the second driver; and a line extending from the winch around the pulley and to the harvest system; wherein the winch is able to wind or unwind the line to move the harvesting system between the first and the second floater.

The seaweed growing system according to claim 14 or 15, wherein the displacement system further comprises tensioner connected to the first float for tensioning the substrate.

The seaweed growing system according to any of claims 14-16, wherein a quick coupling device is mounted on the first float for connecting and locking the substrate with the growing system.

The seaweed growing system according to any of claims 14-17, wherein an active driver is provided to actively submerge the first driver and / or the second driver by adding or removing fluid to or from a liquid tank connected to the first and second floater, and a control device for controlling the immersion and floating. -0-0-0-0-0-0-0-0-0-