Abstract: The invention relates to a pump housing (2) comprising a dual-wall casing (3) which enables a first fluid (4) to flow at least partially around a compression chamber (5) for compressing a second fluid (6), said compression being performed with at least two elongated rotors (7, 8). The dual-wall casing (3) comprises: (i) a first wall (10) which defines the volume of the compression chamber (5), and (ii) a second wall (11) which extends around the first wall (10) at a distance (12) from same such as to enable the first fluid (4) to flow therethrough. The pump housing (2) consists of two subassemblies (13, 14), namely a first subassembly (13) and a second subassembly (14), which are assembled along a sealing surface (15) that is essentially orthogonal to the longitudinal axes (70, 80) of the rotors (7, 8).

Abstract: Rotary displacement machine having a housing and at least two twinned rotors of asymmetrical profile, the twinned rotors each made of a core on which projects a helicoidal thread which extends above the core like a tooth. The helicoidal thread having a first predetermined dimension in a direction radial to the longitudinal axis of the twinned rotors and above the surface of a rotor. The machine having a first flank with a position and length of arc predetermined such that the shape of the first flank and the shape of the second flank each connect to one of the opposite ends of a connecting segment which constitutes a helicoidal surface. The connecting segment having a second predetermined dimension in a direction radial to the longitudinal axis of the twinned rotors such that the ratio of the second dimension over the first dimension ranges between 0.005 and 0.1.

Abstract: Rotary displacement machine comprising un housing and at least two twinned rotors referred to as being of asymmetrical profile, these twinned rotors each being made up of a core on which projects a helicoidal thread which extends above said core in the manner of a tooth which tooth has a first predetermined dimension in a direction radial to the longitudinal axis of that of the twinned rotors under consideration and above the surface of this rotor, this machine being characterized in that instead of comprising a first flank and a second flank of which the conventional shapes and connect at a first point in such a way as to form a sharp edge along the helicoidal thread: on the one hand, said first flank has a shape, referred to as modified shape, of which the position and the length of arc are predetermined such that said modified shape of this first flank and the conventional shape of the second flank each connect to one of the opposite ends and of a short segment, referred to as connecting segment, whic