Patent ID: 8864479

Claim:
A multi-stage scroll machine intended to compress and/or expand a fluid, comprising: first and second volute casing describing an orbital relative movement, the first volute casing being equipped with at least one scroll and the second volute casing being equipped with at least one first scroll and at least one second scroll, the at least one first scroll of the second volute casing being engaged in the scroll of the first volute casing so as to delimit at least a first series of variable-volume chambers belonging to a first compression or expansion stage, and the at least one second scroll of the second volute casing being engaged in the scroll of the first volute casing so as to delimit at least one second series of variable-volume chambers belonging to a second compression or expansion stage, each compression or expansion stage comprising at least one high-pressure fluid passage arranged to open into at least one of the chambers of the respective stage and at least one low-pressure fluid passage arranged to open into at least one of the chambers of the respective stage, the high-pressure fluid passage of the first stage and the high-pressure fluid passage of the second stage being configured so that the fluid passing through the high-pressure fluid passage of the first stage has a lower pressure than that of the fluid passing through the high-pressure fluid passage of the second stage or, the lower-pressure fluid passage of the first stage and the low-pressure fluid passage of the second stage being configured so that the fluid passing through the low-pressure fluid passage of the first stage has a pressure lower than that of the fluid passing through the low-pressure fluid passage of the second stage, wherein a portion of the low-pressure fluid passage of the second stage that is arranged to open into at least one of the chambers of the second stage is further from a first convergence zone of the scrolls delimiting the variable-volume chambers of the second stage than a portion of the high-pressure fluid passage of the first stage that is arranged to open into at least one of the chambers of the first stage, the first convergence zone being located at a center portion of the first volute casing; and wherein the at least one first scroll and the at least one second scroll of the second volute overlap one another so that, according to at least one radial cross-section of the second volute casing along a radius in which the at least one first scroll and the at least one second scroll overlap, at least one alternation of the at least one first scroll and the at least one second scroll of the second volute casing is achieved from a second convergence zone of the at least one first scroll and the at least one second scroll of the second volute casing, the second convergence zone being located at a center portion of the second volute casing.