OIL SPILL RESPONSE Self-inflating boom offers high breaking strain

Bohus Invest has added to its range of oil-related environmental products with the Walboom 450 oil containment boom. Deliveries of the boom, which has been designed to be deployed by one man, have been made to the Swedish coast guard and to customers in Taiwan and South Korea.

Bohus Invest has added to its range of oil-related environmental products with the Walboom 450 oil containment boom. Deliveries of the boom, which has been designed to be deployed by one man, have been made to the Swedish coast guard and to customers in Taiwan and South Korea.

The Walboom 450 is made of a tough polyurethane compound and polyester fibre for strength and durability. It is suitable for temperatures of -10 C to +50 C and wave heights up to 2.5 meters. At 6.7 kg/meter, the boom is comparatively lightweight. It is supplied in 15.4-meter lengths which can be locked together with a rod and slide system. Up to 500 metres of boom can be reeled on a cassette. Cassettes are supplied with the length of boom required by the customer.

What distinguishes Walboom 450 from most of the competition is its ability to self-inflate, according to managing director Christer Hassleback. The boom is given its shape by diamond-shaped frames along its length which lie folded flat while the boom is reeled but spring into shape thanks to the operation of a spring and the force in the frame-legs as the boom is deployed from the reel.

Air is drawn in through inlets at the top of the boom. These inlets consist of small hoses rather than valves, though they operate in such a way as to prevent the air from escaping while the boom is deployed, while allowing the air to be expelled when the boom is being reeled in after use. Air-tight bulkheads are placed at intervals of one-two metres along the boom so that if one section is punctured and the air escapes, the buoyancy of the boom as a whole is not affected.

The frame itself consists of plastic parts, apart from the springs which are of stainless steel. It is assembled in specially welded pockets inside the boom, thus making it easy to replace any part if maintenance is necessary. Ballast for the boom is provided in the shape of galvanised chain running the length of the skirt.

The boom can be towed from either or both ends. The company recommends a maximum towing speed of 10 knots, but with a breaking strain of 4 tons, the Walboom 450 can withstand the roughest treatment, Hassleback says. The Walboom 450 takes its name from its 450 mm freeboard. A smaller version, the Walboom 350, is also available.

Skimmers

Complementing its boom products is Bohus Invest's Walosep oil skimmer. Well established in the market with sales numbering more than 300, the Walosep uses a slow turning submerged rotor to create a suction effect at the surface, thus drawing the oil into the centre off the skimmer from where it is pumped into tanks for later disposal. The system collects oil with a minimum amount of water and can handle a range of conditions from moonshine-thick slicks to glutinous lumps several inches thick, the company claims.

The Walsoep comes in three sizes, of which the largest, W4, is intended for offshore use - it has a pump capacity of 90 cu meter/hour and can operate in waves up to three meters high and winds of 9 meter/sec.

For more information contact Christer Hassleback, Bohus Invest: telephone +46 522 980 82 or fax +46 522 194 78.

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