19 u2033 19 u2033 u2032 which are connected to each other through overflow ducts 28 and 29 an actor 30 30 u2032 and 30 u2033 is assigned to each of the transporting ducts 19 u2032 19 u2033 and 19 u2033 u2032 by successively actuating the actors a fluid can be transported from an inlet duct 8 to an outlet duct 9 or vice versa the volume of the transporting duct 19 formed by deflection of the films 2 3 may also depend through the extent of the deflection of the film 3 beyond the film 2 on the input pressure of the fluid to be transported in order to be able to take into consideration volumes of the transporting duct of different sizes during the fluid transport it is essential to know the respective size of the transporting duct fig9 shows various possibilities for measuring the deflection or the magnitude of the volume of the transporting duct in particular in applications in which the input pressure of a fluid to be transported is variable for example in the field of medicament dosing it may be necessary to control the deflection of the films in order to be thereby able to control the flow through.