GB2247708A - Trap for matter suspended in water - Google Patents

Abstract

A trap (1) for trapping matter suspended in water comprises an elongate member of plastics material having a first and a second compartment (2, 3). The first compartment (2) containing a plurality of concrete balls (11) held in situ by a plastics mesh 12. The second compartment comprises a chamber having a first (20) and second opening for ingress of suspended material. <IMAGE>

Description

MARINE TRAP This invention relates to a marine trap. The traps are for trapping solid material such as sand, mud, pebbles, clay and the like. The traps of the invention are intended for use in the construction of breakwaters, artificial islands and reefs. These and other uses will become apparent hereinafter.

According to the invention there is provided a trap for trapping matter suspended in water the trap comprising a ballast compartment containing ballast and a trap compartment each compartment provided with means for the ingress of suspended matter.

An embodiment of the invention will be illustrated by reference to the accompanying figures of which Figure 1 is a cross-sectional elevation of a trap, and Figure 2 is a top-plan view of the trap.

Figure 3 is an end elevation of the trap.

The trap can comprise a semi-cylindrical member 1. Member 1 comprises a first, ballast, compartment 2 and a second, trap, compartment 3. Member 1 is conveniently made of thermoplastics material and preferably is made by injection moulding. The ballast compartment 2 contains ballast 10.

Typical suitable ballasts include, sand, scrap iron, rubble and concrete. A particularly preferred ballast comprises a plurality of lumps, especially balls 11 of low aggregate concrete. The balls may be reinforced with glass or other fibres. The ballast 10 is secured in the ballast compartment 2. In the case of sand, compartment 2 may be completely sealed or the sand held within a relatively impervious bag or other container.

The other materials may be held in this manner or by a mesh 12. Mesh 12 is advantageously of plastics material.

Sufficient ballast is provided to sink the trap in water.

Preferably sufficient ballast is provided so that little wave and current induced movement of the trap will occur in use. Typically a semi-cylindrical trap of length 1.5m, width 0.5m and height 0.25m will be provided with a ballast compartment taking up the extreme 0.25m of an end.

In the preferred embodiment the balls 11 are held in place by a plastics mesh 12 and the ballast compartment 10 is provided with one or more holes 13 a function of which will become clear hereinafter.

The trap compartment 3 is provided with a relatively large opening 20 preferable at or near one end thereof and one or more smaller holes 21.

When manufactured the traps are of light weight and thus a vessel may carry a large quantity thereof. When cast into the water the traps rapidly sink to the bed. Sand and other debris 100 is washed into the trap compartment 3 and settles further securing the trap on the bed.

In the preferred embodiment suspended material 200 is also carried into the ballast compartment 2 via hole 13 and settles increasing the trap's capacity. Suspended matter also collects on the outside of the trap especially when a large number of traps are deposited at one site. Eventually the traps may become completely enveloped forming sandbanks, islands or breakwaters apparently natural to the casual observer.

The traps of the invention prevent the full force of waves from reaching the shore and other structures thereby reducing erosion and undercutting. The traps of the invention can also prevent silting of channels by trapping suspended matter before it reaches the point were it would normally be deposited.

Modification will be apparent to those skilled in the art.

For example the ballast compartment may lie along the base 14 of the trap 50 as to increase the likelihood of the trap lying of the bed with base 14 downwards. Furthermore it is not essential that eithe rcompartment be situate at a free end of the trap.

Claims (7)

1. A trap for trapping matter suspended in water,r the trap comprising an elongate member of plastics material having a first and a second compartment, the first compartment comprising a plurality of concrete balls held in situ by a plastics mesh, the second compartment comprising a chamber having a first and a second opening for ingress of suspended material.

2. A trap as claimed in claim 1 wherein the first compartment occupies one end of the member.

3. A trap as claimed in claim 1 or claim 2 wherein an opening of the second compartment is situate at a free end of the member.

4. A trap as claimed in any one of the preceding claims wherein the elongate member is a semi-cylinder.

5. A trap substantially as described herein.

6. The use of a trap as claimed in any one of the preceding claims in the construction of breakwaters, artificial banks or islands.

7. The use of a trap as claimed in any one of claims 1 to 5 in reducing the silting of waterways.

7. The use of a trap as claimed in any one of claims 1 to 5 in reducing the silting of waterways.

AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS CLAIMS 1. A trap for trapping matter suspended in water, the trap comprising an elongate member of plastics material having a first and a second compartment, the first compartment comprising a plurality of concrete lumps held in situ by a plastics mesh, the second compartment comprising a chamber having a first and a second opening for ingress of suspended material.

2. A trap as claimed in claim 1 wherein the first compartment occupies one end of the member.

3. A trap as claimed in claim 1 or claim 2 wherein an opening of the second compartment is situate at a free end of the member.

4. A trap as claimed in any one of the preceding claims wherein the elongate member is a semi-cylinder.

5. A trap substantially as described herein.

6. The use of a trap as claimed in any one of the preceding claims in the construction of breakwaters, artificial banks or islands.