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Filter Unit Applications

The many applications of filter units include subsea solutions such as anti-scouring measures at the base of wind turbines and other underwater towers, and protection of marine cables where swaying or friction at cable crossing points could otherwise occur. In addition these versatile rock bags are used as a flexible means of levelling uneven seabeds prior to cable laying.

Their uses also include river bank and emergency zone protection to shore up and prevent further erosion in aquatic environments. They can be installed alongside gabions when used for river bank applications.

1. Scour protection

Without counter measures against scouring

Base of turbine without anti-scouring measures.

Scouring was observed around the foundation of a turbine.

Scouring observed over time.

Filter Units installed for scour protection of foundation of wind turbine

Filter Units were installed.

Scouring was prevented by Filter Unit.

Scouring prevented by Filter Unit.

1. Cable Protection

Without counter measures against scouring

Undersea cable without anti-scouring measures in place.

Cable sways

Cable sways.

If cable sways continuously, it may be seriously damaged.

If cable sways continuously, it may be seriously damaged.

Swaying of cable is restrained by weight of Filter Unit.

Filter Units were installed.

Swaying of cable is restrained by weight of Filter Unit.

Swaying of cable is restrained by weight of Filter Unit.

Filter Unit will be applied in multiple lines when velocity of flow is fast.

Filter Unit installed in multiple lines in an area of high velocity flow.

3. Adjustment of uneven seabed for cable and pipeline installation

Uneven seabed is adjusted by Filter Unit at cable and pipeline installation.

rock bags

Place Filter Unit where cable or pipeline is installed.

rock bags

Filter Units are installed into the gap.

Adjustment of unevenness of the seabed for cable and pipeline

Cable or pipeline is installed.

4. Creation of crossing for cable or pipeline.

Filter Units installed at the crossing point of “cable and cable” or “cable and pipeline.” Required gaps are created preventing contact between the cable and pipeline, thus stabilizing the crossing.

Cable and pipeline protection and counter measures of pipeline floating.

Install Filter Units on the top of cable or pipeline.

Creation of cable and pipeline crossing.

Cable or pipeline will be installed on the top of existing cable or pipeline.

rock bag filter units

Filter Unit will be installed on the top of crossing to stabilize the crossing.

Example Of Construction

Use of Filter Unit For Offshore Wind Farm Construction

filter unit application1

1. Application: Scour Protection at base of Wind Turbine

filter unit application 2

2. Application: Protection Of Export Cable

filter unit application 3

3. Application: Adjustment Of Uneven Seabed

filter unit application 4

4. Application: Protection Of Array Cable

filter unit application 5

5. Application: Protection Of Crossing Point

filter unit application6

6. Application: Protection at base of J-tube

Application Illustration Note Example
River Bank Protection The bag is used at the front of bank independently as foot protection. The installation methods are step piling and random piling.
Foot Protection Filter Unit installed on riverbed. In order to construct it without gaps small size filling is recommended.
River Dike Protection Step pilling applies at a slope of 1:2 or less (steep).
Level installation applies at a slope which is more than 1:2 (gradual incline).
Riverbed Protection Installation on riverbed. In order to construct it without gaps small size filling is recommended.
Application Illustration Note Example
Over Block Filter Unit is used on foot protection blocks. It may be used as a vegetation base with earth covering.
Under Block By using it under a foot protection block or a covering stone, the structure on top is protected from subsidence by sucking etc.
With Other
Filter Unit installed in wooden pile or other methods of construction at inside, back and front. This fits easily with other construction methods.
Protection Of Front Part Bank protection such as gabions, sandbags and sheet pile etc. are stabilized by installing the filter unit in front.
Emergency Procedure Filter unit is installed at an emergency zone and further erosion is prevented. Additional units can be added due to flexibility.
Temporary Road To avoid damage to the Filter Units by placing heavy construction machinery directly on them, please install a steel plate on top.
Filter Unit With Gabion We recommend the use of Filter Units along with gabions in marine or other aquatic environments, where installing  gabions alone is difficult.