Irrigation/aspiration system, cartridge, pump unit, surgical machine, method for controlling

An irrigation/aspiration system for irrigating and aspirating a surgical site comprising:

• an irrigation flow path for directing fluid towards the surgical site via an irrigation connection;
• and
• an aspiration flow path for directing fluid away from the surgical site via an aspiration connection,
• wherein in the aspiration flow path a membrane pump is arranged for pumping fluid through the aspiration flow path, and
• wherein the membrane pump comprises a main pump chamber, at least two valves including a first valve and a second valve for opening and/or closing the main pump chamber and, an auxiliary pump chamber having both its input and its output connection arranged between the aspiration connection and the main pump chamber for compensating movement of a main pump plunger element in the main pump chamber to provide for an approximately even fluid flow from the surgical site, and
• wherein the main pump chamber is arranged with the auxiliary pump chamber in series along the aspiration flow path,
• wherein the first valve is located between the main pump chamber and the auxiliary pump chamber, and the second valve is located downstream from the main pump chamber in the aspiration flow path,
• wherein the second valve is configured to be closed when the main pump plunger element moves upwardly to open the aspiration flow path such that the fluid is smoothly pumped out of the surgical site towards the main pump chamber and the auxiliary pump chamber.