Patent ID: 8459961

Claim:
Multistage compressor unit consisting of a low-pressure charging device ( 2 ) having a low-pressure compressor housing ( 4 ), a high-pressure charging device ( 1 ) having a high-pressure compressor housing ( 3 ) and a cooling device ( 10 ), characterised in that the cooling device ( 10 ) comprises a cooling device housing ( 13 ) and the cooling device housing ( 13 ) of the cooling device ( 10 ) is indirectly connected to the low-pressure compressor housing ( 4 ) of the low-pressure charging device ( 2 ) and the high-pressure compressor housing ( 3 ) of the high-pressure charging device ( 1 ), wherein at least one compressor housing ( 3 , 4 ) of a pressure charging device ( 1 , 2 ) comprises a flange ( 9 ) which defines passages for compressed air and at least one stream of coolant, wherein the passages for at least one stream of coolant pass through a cross section of the flange which extends outwardly from the at least one compressor housing ( 3 , 4 ), and wherein a connection between an outlet or inlet of a pressure charging device ( 1 , 2 ) and an inlet or outlet of the cooling device ( 10 ) is constructed as a flange connection ( 7 ), wherein a portion of the flange which extends outwardly from the at least one compressor housing ( 3 , 4 ) defines the passages for the at least one stream of coolant.