Cable Layer

a mechanism for laying underground and submerged cables. Cable layers in common use can be classified according to the design of their operational member as blade-type (loosening action), hydraulic, and rotor-type mechanisms.

A blade-type cable layer is intended to lay cables in thawed clayey or sandy soils or in previously loosened frozen and stony soils. This type of mechanism can also be used to lay cables across small rivers, canals, and other bodies of water (for cables buried in the bottom). If tractors cannot pass through a river or swamp because of depth greater than 1 m or slimy bottom, the tractive effort from the tractor or towing winch is applied to the cable layer through long cables. When a cable layer is towed by tractors, the blade loosens the soil to a depth of up to 1.5 m and forms a narrow slit between the loosening part and the surface of the soil. A hollow container is fastened by hinges to the rear side of the blade; one or more cables pass through it and are laid on the bottom of the slit. The forward blade loosens the top layer of soil and removes obstacles, such as stones or roots. The tractive effort required depends on the density of soil and on the desired depth of the cable run; it ranges from 150 to 500 kilonew-tons (15-50 tons-force). The tractive effort can be provided by three to seven tractors. The output of blade-type cable layers is up to 5 km of cable run per shift (8 hr). There are also blade-type underwater cable layers, which are used to bury coastal sections of marine and ocean cables in the bottom to protect them against damage caused by trawling or dredging operations. An underwater cable layer is towed by a ship at a speed of 1-3 km/hr and slides along the bottom (at depths up to 200 m) on skids, digging a trench approximately 0.1 m wide and 0.6-0.7 m deep. Such a cable layer is equipped with a television camera, a hydrophone, and instruments to measure the speed and the distance covered. All data from the bottom are transmitted to the ship through a special connecting cable.

A hydraulic cable layer is intended for laying cables across large rivers. For this purpose a pump on the ship discharges water through a pipe at a head of 10 m. Water leaves the pipe through a nozzle at the desired depth and forms a strong jet that washes away the soil. Another pipe is mounted along the water pipe. The cable passes through this second pipe, corresponding to the movement of the ship, and unwinds from a cable drum mounted on the ship. The cable is laid in the trench formed by the action of the water jet. The output of a hydraulic cable layer is 10-30 m/hr.

A rotor-type cable layer is intended for laying cables in thawed and frozen soils. It consists of a self-propelled rotor excavator, of a trailer carriage, and of equipment for loading, transporting, and laying the cable. The main working member of the mechanism is a disk or wheel with cutting teeth. The output of a rotor-type cable layer is up to 1 km per shift (8 hr).