A turbine for a breathing assistance apparatus with improved gas tightness. Abstract: The invention concerns a turbine for a breathing assistance apparatus comprising an electric motor (1) cooperating with a vaned rotor (2) to generate a gas stream, and a volute (3, 4) comprising a lower volute portion (3) and an upper volute portion (4) with a gas inlet passage (5), which couple together and are shaped so as to form an internal compartment in which the vaned rotor (2) is disposed, and in which the lower volute portion (3) comprises a first peripheral rim (3a) and the upper volute portion (4) comprises a second peripheral rim (4a), said first peripheral rim (3a) and second peripheral rim (4a) facing each other when the lower volute portion (3) is coupled to the upper volute portion (4). At least one structure made from an elastomeric material is arranged between or around at least a portion of the peripheral rims (3a, 4a) of the two volute portions (3, 4). A breathing assistance apparatus equipped with a turbine according to the invention. Figure
