| 摘要 |
FIELD: ventilation of subways and underground tunnels. SUBSTANCE: metal air ducts of ventilation plant bringing the upper horizontal workings in communication with lower ones are rigidly secured only on body of lower horizontal working. Upper ends of above-mentioned air ducts are freely received by holes in body of upper horizontal working; air ducts are provided with cylindrical casing with heat and hydroinsulation. In case of change in temperature of air being ventilated, working pipes of air ducts are not subjected to mechanical stresses at thermal contraction. Besides that, diameter of pipes of upper portion of casing exceeds diameter of pipes the main (lower) portion of casing by at least 1.4 times, thus facilitating erection of air ducts from ground surface. EFFECT: avoidance of damage to air ducts in case of sharp change in surrounding temperature. 1 dwgn
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