A process for producing exchange devices for medical use and exchange device produced thereby

An exchange device for medical use, such as a dialyser, comprises a bundle of hollow exchange fibres (12), arranged in a housing (14) that receives the fibres (12), defining a first flow path for a first fluid, such as blood, which can flow within the fibres, and a second flow path on the outside of the fibres for a second fluid, such as a dialysis bath. The ends of the fibres (12) are incorporated in potting masses (16) that co-operate with the housing (14) for separating from one another in a sealed way the paths of flow of the blood and of the dialysis bath. Associated to the potting masses (16) are seals (26) having a branch (26b) co-operating the respective potting mass (16). The potting mass (16) has for this purpose a steplike formation (16a) forming a shoulder for the branch (26b) of the static seal (26). The device is subjected to thermal sterilization, for example steam sterilization, and the steplike formation (16a) is made with a height (h) that, prior to thermal sterilization, is at least equal to 0.7 millimetres.