Volumetric expander, process of starting the volumetric expander, closed-cycle plant, and process for converting thermal energy into electric energy using said plant

摘要

A volumetric expander (4) comprising a casing (50) having a general inlet and outlet (51, 52), a piston (6) operating inside the casing and adapted to define an expansion chamber (7) with variable volume, a main shaft (11) connected to the piston (6), and a valve (6) for selectively opening and closing an inlet and an outlet (8, 9) of the expansion chamber (7) allowing: a condition of introduction of the working fluid in the expansion chamber (7), a condition of expansion of the working fluid in the expansion chamber (7), and a condition of discharge of the working fluid from said expansion chamber (7). The expander comprises a transmission member (53) connected—on one side—to the valve (10) and—on the other side—to the main shaft (11). The casing (50) defines a discharge chamber in direct communication with the general outlet (52) and configured for being put in direct fluid communication with the outlet (9) of the expansion chamber (7) during the condition of discharging the working fluid from the expansion chamber (7) itself. The transmission member (53) is disposed in the casing (50) inside the working fluid discharge chamber. The casing (50) comprises an auxiliary inlet (59) which is only directly in communication with the discharge chamber of the casing (50) and through this latter, with the general outlet (52); the auxiliary inlet (59) is configured for enabling the working fluid to directly enter the casing (50).