Installation comprising a furnace, said furnace comprising: • a chamber defined on the one hand, by a floor and, on the other hand, by a refractory jacket, said jacket comprising walls (112, 113, 114, 115) and a vault, and said chamber comprising a smoke outlet, and • between four and twenty oxygen burners (107, 109) directed towards the inside of the chamber, at least one first series of said oxygen burners being aligned in a first wall of the chamber along a first direction, said installation also comprising: • a heating device to heat a heat-transfer fluid by means of smoke released from the chamber obtaining hot heat-transfer fluid, said heating device being connected to the smoke outlet of the chamber, • a primary heat exchanger to preheat industrial oxygen by heat exchange through a wall with the hot heat-transfer fluid so as to obtain the preheated industrial oxygen, said primary exchanger being adjacent to the jacket of the chamber and connected to the heating device and comprising at least one preheated industrial oxygen outlet (1, 2, 3, 4, 131, 132) to provide preheated industrial oxygen to at least one of the oxygen burners (107, 109), characterised: • in that the installation comprises a splitter to split the industrial oxygen to be preheated into several oxygen flows to be preheated, said splitter being positioned upstream of the primary exchanger or in an oxygen inlet zone inside the primary exchanger, and • in that the primary exchanger comprises several outlets to provide a preheated industrial oxygen flow (1, 2, 3, 4, 131, 132), each oxygen burner of the first series being connected to an outlet (1, 2, 3, 4, 131, 132) of the primary heat exchanger to provide a preheated industrial oxygen flow to said oxygen burner, no outlet of the primary exchanger being connected to several oxygen burners. • a chamber defined on the one hand, by a floor and, on the other hand, by a refractory jacket, said jacket comprising walls (112, 113, 114, 115) and a vault, and said chamber comprising a smoke outlet, and • between four and twenty oxygen burners (107, 109) directed towards the inside of the chamber, at least one first series of said oxygen burners being aligned in a first wall of the chamber along a first direction, • a heating device to heat a heat-transfer fluid by means of smoke released from the chamber obtaining hot heat-transfer fluid, said heating device being connected to the smoke outlet of the chamber, • a primary heat exchanger to preheat industrial oxygen by heat exchange through a wall with the hot heat-transfer fluid so as to obtain the preheated industrial oxygen, said primary exchanger being adjacent to the jacket of the chamber and connected to the heating device and comprising at least one preheated industrial oxygen outlet (1, 2, 3, 4, 131, 132) to provide preheated industrial oxygen to at least one of the oxygen burners (107, 109), characterised: • in that the installation comprises a splitter to split the industrial oxygen to be preheated into several oxygen flows to be preheated, said splitter being positioned upstream of the primary exchanger or in an oxygen inlet zone inside the primary exchanger, and • in that the primary exchanger comprises several outlets to provide a preheated industrial oxygen flow (1, 2, 3, 4, 131, 132),