A device (1) for dispensing charges of a fluid includes a housing (2) provided with a first (3) and a second (4) inlet for a first and a second flow of fluid to flow into the device. First and second fluid communication elements (9, 10) are arranged between the first (3) and second (4) inlets and a first chamber (6). A piston (11) in the first chamber (6) is arranged for keeping the first and the second flows separated. A plunger (13) in a second chamber (14) is arranged for establishing alternately a first charge out of the first flow and a second charge out of the second flow. Third (17), fourth (18) and fifth (19) fluid communication elements arranged between the first and the second chambers and an outlet (20) in cooperation with the piston and the plunger enable alternately dispensing the first and second charges at the outlet.