FLEXIBLE ROPE NET GABION

Abstract

A transportable, flexible rope net gabion useful for scour protection includes a lifting ring, a plurality of polymer ropes connected to the lifting ring, a polymer net connected to the polymer ropes, and a plurality of stones or boulders. Up to 45% of the volume of the polymer net is packed with the stones or boulders, so that the rope net gabion can be evenly positioned around a structure to be supported. The polymer ropes, the polymer net, or both the polymer ropes and the polymer net are made using virgin high density polyethylene (HDPE).

Claims

1. A transportable, flexible rope net gabion for scour protection comprising: a. a lifting ring; b. a plurality of polymer ropes connected to the lifting ring; c. a polymer net connected to the polymer ropes, the polymer net having a volume; and d. a plurality of stones or boulders, wherein up to 45% of the volume of the polymer net is packed with the plurality of stones or boulders, such that the rope net gabion could be evenly positioned around a structure to be supported; wherein the polymer ropes, the polymer net, or both the polymer ropes and the polymer net are made from 20% to 100% by weight of high density polyethylene (HDPE).

2. The rope net gabion as claimed in claim 1, wherein the HDPE is virgin HDPE of ethylene or bioethylene.

3. The rope net gabion as claimed in claim 1, wherein the HDPE is a polymer of bioethylene produced by dehydration of ethanol.

4. The rope net gabion as claimed in claim 2, wherein the HDPE is a polymer of bioethylene produced by dehydration of ethanol.

5. The rope net gabion as claimed in claim 1, wherein the polymer ropes, the polymer net, or both the polymer ropes and the polymer net are made from 20% to 100% by weight of virgin HDPE and 0% to 80% of virgin polyester.

6. The rope net gabion as claimed in claim 5, wherein the virgin polyester is virgin polyethylene terephthalate.

7. The rope net gabion as claimed in claim 1, wherein the polymer ropes, the polymer net, or both the polymer ropes and the polymer net are made from 20% to 90% by weight of virgin HDPE and 10% to 80% of virgin polyester.

8. The rope net gabion as claimed in claim 1, wherein the polymer ropes, the polymer net, or both the polymer ropes and the polymer net are made from 50% to 100% by weight of virgin HDPE and 0% to 50% of virgin polyester.

9. The rope net gabion as claimed in claim 1, wherein the polymer net is a knotted net.

10. The rope net gabion as claimed in claim 1, wherein the polymer net is a knotless net.

11. The rope net gabion as claimed in claim 1, wherein the polymer net is monolithically connected to the plurality of polymer ropes.

12. The rope net gabion as claimed in claim 1, wherein: the polymer net is made from 50% to 100% of virgin HDPE and 0% to 50% of a virgin polyester; and the polymer ropes are made from the virgin polyester.

13. The rope net gabion as claimed in claim 1, wherein: the polymer ropes are made from 50% to 100% of virgin HDPE and 0% to 50% of a virgin polyester; and the polymer net is made from the virgin polyester.

14. The rope net gabion as claimed in claim 1, wherein: both the polymer ropes and the polymer net are made from 50% to 100% of virgin HDPE and 0% to 50% of a virgin polyester.

15. The rope net gabion as claimed in claim 1, wherein: the polymer net is made from 50% to 100% of virgin HDPE and 0% to 50% of a virgin polyester; and the polymer ropes are made from the virgin HDPE.

16. The rope net gabion as claimed in claim 1, wherein: the polymer ropes are made from 50% to 100% of virgin HDPE and 0% to 50% of a virgin polyester; and the polymer net is made from the virgin HDPE.

17. The rope net gabion as claimed in claim 1, wherein: both the polymer ropes and the polymer net are made from virgin HDPE.

18. A method of making a rope net gabion comprising a lifting ring, a plurality of polymer ropes, and a polymer net having a volume, the method comprising: making the plurality of polymer ropes from 20% to 100% by weight of HDPE and 0% to 80% by weight of virgin polyester; connecting the plurality of polymer ropes to the lifting ring; connecting the polymer net to the plurality of polymer ropes; and filling up to 45% of the volume of the polymer net with a plurality of stones or boulders.

19. The method of claim 18, further comprising making the polymer net from 20% to 100% by weight of the HDPE and 0% to 80% by weight of the virgin polyester.

20. A method of making a rope net gabion comprising a lifting ring, a plurality of polymer ropes, and a polymer net having a volume, the method comprising: obtaining HDPE manufactured from bioethylene produced by dehydration of ethanol; making the polymer net from 20% to 100% by weight of the HDPE and 0% to 80% by weight of virgin polyester; connecting the plurality of polymer ropes to the lifting ring; connecting the polymer net to the plurality of polymer ropes; and filling up to 45% of the volume of the polymer net with a plurality of stones or boulders.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0024] FIG. 1 illustrates the flexible rope net gabion in accordance with one of the embodiments of the invention.

[0025] FIG. 2 illustrates the open state of the polymer net 3.

[0026] FIG. 3 illustrates one embodiment of using the flexible rope net gabion 3 of the invention for anchoring the structure.

[0027] FIGS. 4A and 4B illustrate turbidity from immersing polymeric ropes suitable for making the rope net gabion of FIG. 1 in water.

[0028] FIGS. 5A and 5B illustrate turbidity from immersing polyester ropes suitable for making the rope net gabion of FIG. 1 in water.

DETAILED DESCRIPTION OF THE INVENTION

[0029] As used herein, the term “polyethylene” refers to a polymer including ethylene monomers. The terms “high density polyethylene” and “ HDPE” refer to a polyethylene with a density of 930 to 970 kg/m.sup.3, and little branching. High density polyethylene may be a iomopolymer of ethylene, or may contain a limited amount of another olefin as a comonomer.

[0030] As used herein, the term “ethylene” refers to an olefin monomer with the formula CH.sub.2═CH.sub.2. Unless otherwise specified, ethylene may be obtained by any method known in the art, including:

Thermal cracking of hydrocarbons found in petroleum;
Oxidative coupling of methane found in natural gas;
Fischer-Tropsch synthesis from carbon dioxide; and
Catalytic dehydrogenation of alcohol.

[0031] As used herein, the term “bioethylene” refers to:

ethylene produced by dehydrogenation of ethanol obtained from a renewable source; or
ethylene produced enzymatically from S-adenosyl-L-methionine.
Polymerization of bioethylene produces HDPE which is structurally and functionally similar to HDPE produced by polymerization of conventionally sourced ethylene, while avoiding environmental issues caused by processes such as thermal cracking of hydrocarbons.

[0032] As applied to polymers herein, the term “virgin” means that the polymer has never been processed into any product before, i.e., the polymer is new. As applied to polymers herein, the term “recycled” means that the polymer has been previously processed into a product; the recycled polymer may have been contaminated with other polymers or other materials.

[0033] The flexible rope net gabion 5 comprises of a lifting ring 1, a plurality of polymer ropes 2, a polymer net 3 and stones or boulders 4.

[0034] The lifting ring 1 functions as a lifting element to facilitate easy lifting of the flexible rope net gabion 5 for positioning, as required. The lifting ring 1 can be hung to a crane. The material used for construction of the lifting ring 1 is a polymer or stainless steel or the like.

[0035] The plurality of polymer ropes 2 which are connected to the ring 1 function as lifting ropes for suspending the flexible rope net gabion 5 from the crane.

[0036] The polymer net 3 is monolithically connected to the plurality of polymer ropes 2. The net is manufactured from a polymer yarn made from a mix of polymer netting and polymer ropes.

[0037] The boulders or stones 4 are held in the polymer net 3. The stones or boulders 4 act as porous structure which provide scour protection to the embedded structure. The size of the boulders is immaterial for efficient implementation of the current invention.

[0038] FIG. 2 details the open state of the polymer net 3 of the flexible rope net gabion 5, having a conical top end and open bottom end. The polymer net 3 comprises of two lacing twines 31A and 31B. The twines 31A and 31B are configured for facilitating tying of the open end after filling the polymer net 3 with stones of boulders 4.

[0039] The polymer net 3 is further adorned with a bottom 10 mm twisted polyester rope 34, disposed close to the top open end, which functions as a load-bearing portion for hanging to hook 1. The polymer net 3 further comprises of multitude of structural ropes 33, which are 6 mm polyester twisted ropes. The structural ropes 33 extend from the top 10 mm twisted polyester ring 32 till a top 10 mm twisted polyester rope ring 34. In accordance with this embodiment the 34 has a diameter which is substantially larger than the diameter of top 10 mm twisted polyester rope ring 34, such that the structural ropes 33 along with the rings 32 and 34 form a substantially conical structure.

[0040] As illustrated in FIG. 3, the flexible rope net gabion 3 packed with rock to an extent of 45% allows the flexible rope gabion 3 to be evenly positioned around the structure 100 to be supported thereby ensuring that it is anchored in a balanced fashion.

[0041] The flexible rope net gabion is used to provide scour protection for bridges, piles, offshore structures, wind turbines, river training, channel lining, erosion control, etc.

[0042] In an embodiment, the material used for construction of the lifting ring 1 is a polymer or stainless steel or the like.

[0043] The polymer ropes 2 and/or polymer net 3 of the flexible rope net gabion 5 is made from a polymer yarn constructed from a mix of polymer netting and polymer ropes. Further, in accordance with current embodiment, said polymer net 3 can be a knotted net or knotless net.

[0044] The net 3 and/or the rope 2 can be made of twisted/braided yarn. The polymer net 3 could be either knotless net or knotted net.

[0045] The polymer net 3 and/or ropes 2 could be made of yarn containing polyolefin with a polyester content varying from 0% to less than 100%, e.g., 10-80% polyester, 0-50% polyester, or 0-25% polyester.

[0046] The polymer net 3 and/or ropes 2 could be made of yarn containing 20-90% polyolefin and 10-80% polyester, 50-100% polyolefin and 0-50% polyester, or 75-100% polyolefin and 0-25% polyester.

[0047] The polyolefin may be high density polyethylene (HDPE) produced using conventionally sourced ethylene or bioethylene. The polyolefin may be virgin HDPE.

[0048] Recycled HDPE is frequently used for preparation of ropes or nets. However, recycled HDPE frequently contains polypropylene or branched polyethylene copolymers as contaminants. Due to their increased levels of tertiary carbon atoms in the polymer backbone, polypropylene and branched polyethylene copolymers are more susceptible to oxidative reactions. These oxidation reactions can lead to chain scission, to produce shorter polymer chains. Additionally, intermediate radicals produced during oxidation of polypropylene or polyethylene copolymers may attack C—H bonds in HDPE, shortening these polymer chains as well. Such degradation may produce microplastics, which are damaging to the environment.

[0049] Similarly, recycled polyethylene terephthalate is also used for preparation of ropes or nets. However, recycled polyethylene terephthalate is also susceptible to oxidative reactions. These oxidation reactions lead to chain scission, leading to shorter polymer chains and production of microplastics.

[0050] The present disclosure shows that ropes or nets made from virgin HDPE or virgin polyethylene terephthalate produce very low levels of microplastics, compared to recycled HDPE or recycled polyethylene terephthalate.

[0051] Similarly, ropes or nets made using threads or yarns containing combinations of virgin HDPE and virgin polyethylene terephthalate produce very low levels of microplastics, compared to ropes or nets made using recycled HDPE, recycled polyethylene terephthalate, or a mixture thereof. Additionally, such combinations of virgin HDPE and virgin polyethylene terephthalate offer advantages not found in either polymer alone. As virgin polyethylene terephthalate has higher tensile strength than virgin HDPE, the presence of virgin polyethylene terephthalate may increase the overall strength of the ropes or nets. Also, virgin HDPE is less prone to chain scission or microparticle formation than virgin polyethylene terephthalate. Thus, if virgin PET and virgin HDPE are used in combination, the virgin polyester increases the strength of the resulting rope or net while the virgin HDPE reduces the susceptibility of the resulting rope or net to chain scission and/or microparticle formation.

[0052] The present disclosure shows that ropes or nets made from virgin HDPE produced using conventionally sourced ethylene or bioethylene produce very low levels of microplastics, compared to recycled HDPE, recycled polyethylene terephthalate, or virgin polyethylene terephthalate.

[0053] The present disclosure shows that ropes or nets made from virgin HDPE produced from polymerization of bioethylene, i.e., ethylene produced from dehydration of ethanol, produce very low levels of microplastics, compared to recycled HDPE, recycled polyethylene terephthalate, or virgin polyethylene terephthalate.

[0054] The yarn used for production of the polymer net 3 and/or ropes 2 is a bio-based yarn.

[0055] The polymer net 3 is packed with rocks to the extent of 45% of the volume of the Net 3. Packing the rock to an extent of 45% of the total volume of polymer net 3 which allows the flexible rope net gabion 5 to be evenly positioned around the structure 100 to be supported thereby, ensuring that the structure is anchored in a balanced manner.

[0056] In an embodiment, the polymer net 3 is monolithically connected to plurality of polymer ropes 2.

[0057] The flexible rope net gabion 5 forms a porous and flexible structure containing stones or boulders 4. Said stones or boulders 4 provide excellent protection from scouring. In accordance with this embodiment, it is possible to achieve effective implementation of the current invention irrespective of the size of the boulders. Further, in accordance with this embodiment, the flexible rope net gabion 5 of the invention could be evenly positioned around the structure to be supported thereby ensuring that it is anchored in a balanced manner.

[0058] In accordance with one of the embodiments, the polymer net 3 of the flexible rope net gabion 5 has a conical top end and open bottom end. The polymer net 3 is equipped of two lacing twines 21A and 21B. The twines 21A and 21B are designed for facilitating tying of the open end after filling the polymer net 3 with stones of boulders 4.

[0059] The plurality of polymer ropes 2 comprises of a bottom 10 mm twisted polyester rope 24, disposed close to the open end of the polymer net 3, which functions as a load-bearing portion for hanging to hook 1. The polymer rope 2 further comprises of multitude of structural ropes 23, which are 6 mm polyester twisted ropes. The structural ropes 23 extend from the top 10 mm twisted polyester ring 22 till a top 10 mm twisted polyester rope ring 24. In accordance with this embodiment the 24 has a diameter which is substantially larger than the diameter of top 10 mm twisted polyester rope ring 22, such that the structural ropes 23 along with the rings 22 and 24 form a substantially conical structure.

[0060] In accordance with one of the embodiments of the invention, the flexible rope net gabion 5 packed with rock to an extent of 45%. The 45% packing allows the flexible rope gabion 5 to be evenly positioned around the structure 100 to be supported, thereby ensuring that the structure 100 is anchored in a balanced fashion.

[0061] In an advantageous embodiment, the flexible rope net gabion of the invention also ensures lower micro-plastic release and lower harm to environment.

[0062] In an advantageous embodiment, the flexible rope net gabion of the invention is eco-friendly.

[0063] In another advantageous embodiment, the specific gravity of the yarn is increased so as to achieve efficient submersion of the flexible net gabions of the invention.

[0064] In another advantageous embodiment, the flexible rope net gabion of the invention provides a porous flexible structure that provides excellent scour protection and is durable.

[0065] In an embodiment of the invention, the flexible rope net gabion of the current invention could be effectively used for preventing scouring or soil erosion from on the water body bed or sea-shore or river bank or riverbed or streambed or stream bank.

[0066] The invention has the following novel features: [0067] The flexible rope net gabion of current invention is flexible and easy-to-transport. [0068] The flexible rope net gabion of current invention is eco-friendly. [0069] The flexible rope net gabion of current invention ensures lower micro-plastic release and lower harm to environment, owing to the composition of the yarns used for construction of the polymer ropes and the polymer net. [0070] The flexible rope net gabion of current invention is durable. [0071] The flexible rope net gabion of current invention could be manufactured using synthetic yarn or a bio-based yarn. [0072] The polymer net 3 of the flexible rope net gabion of current invention could be either knotless net or knotted net. [0073] The polymer net is monolithically connected to plurality of polymer ropes. The effective implementation of the flexible rope net gabions of current invention can be achieved irrespective of the size and shape of the boulders. [0074] The flexible rope net gabion of the current invention could be effectively used for preventing scouring or soil erosion from the water body bed or sea-shore or river bank or riverbed or streambed or stream bank.

[0075] In the examples below, all HDPE ropes are manufactured from virgin high density polyethylene, using bioethylene produced by dehydration of ethanol.

EXAMPLES

[0076] The following examples describe tests carried out on net materials containing polyester and/or HDPE. Studies of turbidity were carried out by placing a sample of a net (10 gm) to be tested and sea water in a steel vessel together, and sealing the vessel. The vessel was tumbled at 75 RPM, for a time period ranging from 0 hours to 6 hours, while maintaining a desired temperature. At the end of the test period, residual water was removed from the sealed vessel and analyzed for turbidity.

Example 1. Resistance of HDPE Net Products to Oxidation

[0077] Test specimens of HDPE net were stored in water at 80° C. for a period of 28 days, with the water changed at least every seven days and moved at least once per day. Test specimens were exposed, freely hanging, in a regulated laboratory oven at an elevated temperature of 100° C. for a period of 112 days. After completion of this oxidation process the test specimens were subjected to a tensile strength test. For the machine direction test, the test specimens incorporated 12 yarn connection points, i.e., 22 complete yarns, and for the cross direction test, the test specimens incorporated 4 yarn connection points, i.e., 18 complete yarns

[0078] Control specimens of HDPE were nominally identical to the test specimens. The control specimens were stored in water at 80° C. for a period of 28 days, with the water changed at least every seven days and moved at least once per day. The control specimens were not subjected to oxidation in a laboratory oven. A tensile strength test was conducted on the test and control specimens. The results are shown in Table 1.

[0079] Based on the data in Table 1, the retained strength values for the above test specimens can be calculated relative to the control specimens. Retained strength of the test specimens is 98% of the strength of the control specimens in the machine direction. Retained strength of the test specimens is 95% of the strength of the control specimens in the cross direction. Thus, the HDPE net do not undergo significant degradation from oxidation.

TABLE-US-00001 TABLE 1 Results of tensile strength test on control and test (exposed) specimens. CONTROL EXPOSED SPECIMENS SPECIMENS Length/ Width Length/ Width machine cross machine cross Direction of specimens direction direction direction direction Mean force at peak (kN) 16.3 3.9 16.0 3.7 Mean force at peak 81.6 15.2 80.0 14.3 (kN/m) Time to peak (secs) 138.3 151.1 143.6 141.1 Elongation at peak (%) 33.1 137.6 34.7 129.3

[0080] Example 2. Percentage weight loss of HDPE net products in water. Test specimens of virgin HDPE net were immersed in water for a period of six hours, at a temperature of 10° C. or 26° C. Test specimens were then removed from the water, completely dried, and weighed. The weight after immersion was compared to the weight before immersion. The test was repeated with virgin PET polyester nets. The virgin HDPE nets and virgin PET polyester nets are 36 ply nets, suitable for preparation of an 8 Ton (lifting capacity) flexible rope net. As seen in Table 2, at both 10° C. and 26° C., the weight loss from virgin polyester was higher than the weight loss from virgin HDPE by a factor of ˜2. Higher weight loss from polyester correlates with increased release of particles of microplastics.

TABLE-US-00002 TABLE 2 Results of HDPE weight loss test on virgin HDPE and virgin PET specimens. Polymer Temperature (° C) Weight Loss (%) Virgin HDPE 10 0.87 Virgin PET 10 1.63 Virgin HDPE 26 0.32 Virgin PET 26 0.69

Example 3. Turbidity of HDPE Net Products in Water

[0081] Test specimens of 36 ply virgin HDPE net were immersed in water for a period of six hours, at a temperature of 10° C. or 26° C. Turbidity of the water was measured hourly in NTU (Nephelometric Turbidity Units; 3 NTU=1 mg/l). The test was repeated with virgin PET polyester nets. Higher turbidity from polyester correlates with increased release of particles of microplastics. As shown in Table 3, and also in FIGS. 4A and 4B, turbidity from virgin polyester after 6 h exceeds turbidity from virgin HDPE by a factor of about 6 to about 8.25, depending on temperature.

TABLE-US-00003 TABLE 3 Turbidity of HDPE and polyester in water. Turbidity (NTU) Time (hr) HDPE, 10° C. HDPE, 26° C. PET, 10° C. PET, 26° C. 0 10.6 10.7 97.1 36.6 1 16.4 13.7 139 101 2 24.6 19.3 200 130 3 27.7 20.4 234 140 4 29.2 26.6 262 197 5 32.5 33.3 280 212 6 34.9 36.6 287 221

Example 4. Turbidity of Polyester Net Products in Water

[0082] Test specimens of 18 ply virgin polyethylene terephthalate net were immersed in water for a period of six hours, at a temperature of 10° C. or 20° C. Turbidity of the water was measured hourly in NTU (Nephelometric Turbidity Units; 3 NTU=1 mg/l). The test was repeated with recycled polyethylene terephthalate nets. As seen in Table 4 at both 10° C. and 20° C., turbidity of water exposed to recycled polyethylene terephthalate was higher than the turbidity of water exposed to virgin polyethylene terephthalate. Higher turbidity from polyester correlates with increased release of particles of microplastics. As shown in Table 4, and also in FIGS. 5A and 5B, turbidity from recycled polyester after 6 h exceeds turbidity from virgin polyester by a factor of about 2 to about 3, depending on temperature.

TABLE-US-00004 TABLE 4 Turbidity of polyester in water. Turbidity (NTU) Virgin PET, Virgin PET, Recycled PET, Recycled PET, Time (hr) 10° C. 20° C. 10° C. 20° C. 0 10.2 10.5 12.2 12.7 1 28.4 35.4 67.2 81.7 2 27.6 37.8 68.2 109 3 28.1 39.5 82.2 125 4 34.4 39.8 81.9 135 5 35.7 53.6 76.4 156 6 58.4 63.7 119 174

[0083] It is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments will be apparent to a person skilled in the art upon reviewing the description. The scope of the invention should therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.