ARRANGEMENT FOR HOLDING TELEPHONE AND GAS-FILLED POWER CABLES UNDER GAGE PRESSURE Russian patent published in 2001 - IPC

FIELD: electrical engineering; power cables and urban telephone networks. SUBSTANCE: arrangement is used to protect cables against ingress of moisture and to check their sheaths for tightness. To this end, use is made of gas-control gas and air medium held at gage pressure. It has membrane-type gas- separation apparatus operating without periodic loading cycles due to provision for check valve 11 inserted between condenser post and apparatus and compressor that depends for its operation on gas-mixture flowrate within cable in pressure build-up mode whose operating time under these conditions is reduced due to preventing abrupt pressure rise in gas-separation apparatus and ingress of humid air in cables. Power- actuated valves 13 and 14 are installed at infiltrated air and nitrogen- enriched dry air vent communicating with atmosphere so that mentioned valves are open during pressure build-up in receiver 16 and close as soon as desired pressure is built up. In this way, pressure within gas-separation apparatus rises only once during starting period and then does not come down upon stopping the compressor. It is known fact that selectivity of gas-separation apparatus and, hence, degree of air drying, increases with pressure drop across membranes. Novelty is that these advantages are implemented by mounting receiver 3, pressure-control reducer 6, and power-operated valve 7 downstream of compressor. Pressure within receiver 7 is maintained slightly above desired value by means of pressure relay 5. Air pressure is decreased in pressure reducer to optimal value just upon passing through power-actuated valve 7 controlled by pressure relay 4, then air is passed to pre-drying facility and to gas- separation apparatus wherein optimal pressure drop is attained. Pressure relay controls operation of compressor 1 with the result that optimal working pressure is immediately applied to membrane-type gas- separation apparatus voiding periodic loading cycles. EFFECT: enhanced life of gas-separation apparatus, eliminated air ingress in cable, reduced time of compressor operation in pressure build-up mode. 3 cl, 1 dwg