New antifoam formulations for the thermal desalination process of water

Formulation F comprising A) 50 to 90 parts by weight of at least one block copolymer P of ethyleneoxide and propylene oxide, B) 0.5 to 10 parts by weight of at least one salt of an alkyl sulfate S, C) 0.05 to 0.5 parts by weight of a composition C comprising C1 ) 5 to 10 parts by weight of at least one polydimethylsiloxane bearing only terminal alkyl groups, C2) 1 to 3 parts by weight of at least one polydimethylsiloxane bearing at least alkoxylated hydroxy group, C3) at least one solvent, wherein said formulation F is an aqueous formulation.