SYSTEM FOR DRAINING A LIQUID STORAGE TANK

摘要

The present invention relates to a system which makes it possible to remove undesirable liquids, generally an aqueous phase, which precipitate to the bottom of tanks for storing liquid products. Use is made of a drainage devic e (30) which comprises a concave body (31), a seat (26), and an interface floa t (8) which has a plug portion (25). This interface float (8) is designed to sink into the product and to float on the aqueous phase. As the level of the aqueous phase drops, the plug portion (25) settles sealingly on the seat (26 ), halting the drainage operations since all the accumulated aqueous phase has already been drained off. The drainage system may be automatic or manual. In the former case, use is made of a sensor (12) for detecting the presence of an aqueous phase and commanding the process of opening a shut-off valve (11) an d allowing drainage of the accumulated aqueous phase. In the manual case, an operator periodically checks for the presence of an aqueous phase inside de storage tank (1), through a port (28) for inspecting the level. If such a phase were to accumulate, he opens a manual shut-off valve (29) so as to all ow all the accumulated aqueous phase to drain away.