Abstract: An intermediate duct (108) is connected between first and second positive displacement machines (104, 106). An inlet duct (107) is connected to the first positive displacement machine (104). An outlet duct (109) is connected to the second positive displacement machine (106). A heater (102) raises the temperature and pressure of a gaseous working fluid in the intermediate duct (108). There is a kinematic connection (111) between the first and second positive displacement machines (104, 106) and the arrangement is such that, in operation, the first positive displacement machine (104) causes the working fluid to flow through the intermediate duct (108) to the second positive displacement machine (106), the heated working fluid drives the second positive displacement machine (106), and the second positive displacement machine (106) drives the first positive displacement machine (104) via the kinematic connection (111). The positive displacement machines include at least one orbiting piston.

Abstract: A rotary displacement machine includes a casing having a circular cylindrical internal surface and a rotor disposed in the chamber mounted to orbit about a chamber axis, with the rotor having a circular cylindrical external surface. A vane member is mounted on the casing and pivotable about a pivot axis parallel to the chamber axis. The vane member has a passage way communicating between the exterior of the casing and the operating chamber. A linkage connects the vane member to the rotor so as to keep a tip face of the vane member in sealing contact with an external surface of the rotor.