Abstract: A volumetric expander comprising a casing having a general inlet and outlet, a piston operating inside the casing and adapted to define an expansion chamber with variable volume, a main shaft connected to the piston, and a valve for selectively opening and closing an inlet and an outlet of the expansion chamber allowing: a condition of introduction of the working fluid in the expansion chamber, a condition of expansion of the working fluid in the expansion chamber, and a condition of discharge of the working fluid from said expansion chamber. The casing defines a discharge chamber in direct communication with the general outlet and configured for being put in direct fluid communication with the outlet of the expansion chamber during the condition of discharging the working fluid from the expansion chamber itself.

Abstract: 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).