Cables with neutral or positive buoyancy
Cables with neutral or positive buoyancy are used for special operations at sea when towed by a vessel. The cables divided by function as generative cables and receiving cables.
Providing necessary drowning, the cable can have different structure on length with additional reinforcing or loading elements.
Designs of generative cables have power conductor with section up to 150 mm2, performed as central flexible copper or aluminium conductor or as a winding by thin copper wires or copper tapes on cable core.
Examples of designs and appearance of cables of this group indicated on Fig.1.
Cable for profiling of sea bedÊP 16õ0,2/10-22PU
Generative cableÊP 16õ0,2/30-37
Fig.1 – Examples of cables with neutral buoyancy
The cables contain up to 16 signal conductors with section 0,2 mm2 (1), power conductors made by winding wire or tape 10 and 30 mm2 (2), load-carrying elements made as strand of fibres “Armos” (3); the cables have positive buoyancy 0-10%, longitudinal sealing and sheath of high pressure polyethylene (4).
One of the latest development of OOO “Pskovgeokabel” is the cable with variable buoyancy mark KPG (6GK 6/9+9×0,2)/Ê40. This cable can change buoyancy from -6% up to +6%.
Fig.2 – design of cable KPG (6GÊ 6/9+9×0,2)/Ê40
Cable KPG (6ÃÊ 6/9+9õ0,2)/Ê40 consists of:
1 – load-carrying element from synthetic yarn with tensile force not less 10 kN;
2 – sheath of load-carrying element;
3 – 9 control conductors with section 0,2 mm2;
4 – insulation of control conductors made of high-pressure polyethylene;
5 – core winded with water blocking nonwoven material with diameter 9 mm;
6 – water blocking nonwoven tape;
7 – 6 hydrochannels produced of low-pressure polyethylene with inside diameter 6 mm and outside diameter 9 mm;
8 – space between hydrochannels is filled with EVA;
9 – intermediary sheath;
10 – screen of soft copper wires with section 40 mm2 winded with of semi-conductive, water blocking nonwoven material;
11 – intermediary sheath of foamed high-pressure polyethylene;
12 – protective sheath of high-pressure polyethylene.