Apparatus for exchanging heat between at least three fluids

An installation for heat exchange between at least three fluids A, B and C, said installation comprising:

• (a) a sealed vessel (1) of elongate shape;
• (b) at least two separate plate bundles (10;
• 40) arranged inside said sealed vessel (1) and each formed of a stack of metal heat-exchange plates (11;
• 41) having corrugations (12;
• 42) and delimiting between them two circuits for circulation of two independent fluids;
• (c) inlet means (13, 14) for introducing a first fluid A into a corresponding circuit of a first of said plate bundles (1);
• (d) means (15, 16, 43) for connecting said first plate bundle (10) with one circuit of a second of said plate bundles (40) to allow said first fluid A to circulate between said first and second plate bundles (10;
• 40);
• (e) outlet means (44, 45) for letting said first fluid A out of the corresponding circuit of said second plate bundle (40);
• (f) inlet means (17, 18) and outlet means (19, 20) for introducing a second fluid B into and letting said second fluid B out of the corresponding circuit of said first plate bundle (10);
• (g) inlet means (46) and outlet means (47, 48) for introducing a third fluid C into and letting said third fluid C out of the corresponding circuit of said second plate bundle (40);
• and
• (h) means for holding each plate bundle (10;
• 40) in said sealed vessel (1).