Patent ID: 8746652

Claim:
A method comprising: operating a valve, wherein the valve has at least one valve seat, a valve plunger and a stepper motor for moving the valve plunger with respect to the or each valve seat, namely for moving the valve plunger from a first position into a second position in which the valve plunger is pressed against a valve seat and for compressing a flexible element assigned to the valve plunger in said second position, whereby the stepper motor is driven in such a way that the stepper motor provides a defined number of steps (N TOTAL ) in order to move the valve plunger from the first position into the second position and in order to compress the flexible element thereby providing tightness between the valve plunger and the valve seat, wherein operating the valve comprises driving the stepper motor in such a way that: for a first number of steps (N 1 ) of said defined number of steps (N TOTAL ), the stepper motor is operated at a first current level (I 1 ); for a subsequent second number (N 2 ) of steps of said defined number of steps (N TOTAL ), the stepper motor is operated at a second current level (I 2 ) being lower than the first current level (I 1 ); and for a subsequent third number of steps (N 3 ) of said defined number of steps (N TOTAL ), the stepper motor is operated at a third current (I 3 ) level being higher than the second current level (I 2 ).