Thermostatic assembly for incorporation in a pipeline (3) conveying liquid (2), designed to prevent damage to said pipeline (3) as a result of freezing, by evacuating only the quantity of liquid (2) which has achieved crystallization conditions, comprising a first automatic sealing device (19) for said pipe (3) linked with a second automatic bleed device (1) for said pipe (3), characterized in that the first and second devices are provided with appropriate means for reacting to the same effects linked with the temperature of the liquid (2) conveyed in the pipe (3) in such a manner that the first device (19) closes off the pipe (3) by means of a cushion (23) before the second device (1) bleeds said pipe (3) by opening a bleed point (5) which is normally closed off by a flap valve (4). |