A rotary machine comprising: an inner rotor and an outer shell, the rotor rotating on a first axis and the shell rotating on a second axis parallel to and offset from the first axis, an external support structure which holds the first and second axes in alignment to each other, and wherein the said axes are substantially stationary relative to the support structure, the said shell having two or more sealing points on its inner surface which interact with the outer surface of the rotor to define two or more working chambers (A, B, C) between the rotor and the shell, said outer surface including a fluid transfer port, a shaft attached to the rotor and concentric with the first axis of rotation, said shaft containing a duct substantially parallel to the first axis of rotation, which duct is connected to a further duct in the rotor and said further duct connected to the port, the duct and further duct together forming a continuous passageway for fluid from the port to a point where the shaft interacts with the support structure, characterised in that: the passageway is bounded entirely by one or more parts, the one or more parts being joined together such that, during operation of the rotary machine, the one or more parts remain stationary relative to one another, thereby allowing fluid flow through the passageway throughout operation of the rotary machine and during operation of the rotary machine the passageway rotates about an axis which is substantially stationary relative to the support structure, such that in use the relative rotation of the rotor to the shell causes the working chambers (A, B, C) to change in size, and whereby the relative movement of the sealing points across the port controls the transfer of fluid between the port and the working chambers (A, B, C), and wherein the passageway is configured such that, during operation of the rotary machine in which the relative rotation of the rotor to the shell is in a first rotational direction, fluid within the passageway flows continuously in a first direction through the passageway between the working chambers (A, B, C) and the point where the shaft interacts with the support structure. an inner rotor and an outer shell, the rotor rotating on a first axis and the shell rotating on a second axis parallel to and offset from the first axis, an external support structure which holds the first and second axes in alignment to each other, and wherein the said axes are substantially stationary relative to the support structure, the said shell having two or more sealing points on its inner surface which interact with the outer surface of the rotor to define two or more working chambers (A, B, C) between the rotor and the shell, said outer surface including a fluid transfer port, a shaft attached to the rotor and concentric with the first axis of rotation, said shaft containing a duct substantially parallel to the first axis of rotation, which duct is connected to a further duct in the rotor and said further duct connected to the port, the duct and further duct together forming a continuous passageway for fluid from the port to a point where the shaft interacts with the support structure, characterised in that: the passageway is bounded entirely by one or more parts, the one or more parts being joined together such that, during operation of the rotary machine, the one or more parts remain stationary relative to one another, thereby allowing fluid flow through the passageway throughout operation of the rotary machine and during operation of the rotary machine the passageway rotates about an axis which is substantially stationary relative to the support structure, such that in use the relative rotation of the rotor to the shell causes the working chambers (A, B, C) to change in size, and whereby the relative movement of the sealing points across the port controls the transfer of fluid between the port and the working chambers (A, B, C), and wherein the passageway is configured such that, during operation of the rotary machine in which the relative rotation of the rotor to the shell is in a first rotational direction, fluid within the passageway flows continuously in a first direction through the passageway between the working chambers (A, B, C) and the point where the shaft interacts with the support structure. the passageway is bounded entirely by one or more parts, the one or more parts being joined together such that, during operation of the rotary machine, the one or more parts remain stationary relative to one another, thereby allowing fluid flow through the passageway throughout operation of the rotary machine and during operation of the rotary machine the passageway rotates about an axis which is substantially stationary relative to the support structure, such that in use the relative rotation of the rotor to the shell causes the working chambers (A, B, C) to change in size, and whereby the relative movement of the sealing points across the port controls the transfer of fluid between the port and the working chambers (A, B, C), and wherein the passageway is configured such that, during operation of the rotary machine in which the relative rotation of the rotor to the shell is in a first rotational direction, fluid within the passageway flows continuously in a first direction through the passageway between the working chambers (A, B, C) and the point where the shaft interacts with the support structure.