Patent ID: 8708665

Claim:
A pumping system comprising a membrane pump ( 1 ) for pumping a medium, the membrane pump ( 1 ) comprising: a pump housing ( 2 ), a membrane ( 3 ), which is mounted to the pump housing ( 2 ) and delimits a pump chamber ( 4 ) inside the pump housing ( 2 ), an inlet ( 5 ) for feeding medium into the pump chamber ( 4 ), the inlet ( 5 ) having a first non-return valve ( 6 ) connected thereto, an outlet ( 7 ) for discharging medium from the pump chamber ( 4 ), the outlet ( 7 ) having a second non-return valve ( 8 ) connected thereto, an axle ( 11 ) attached to the membrane ( 3 ), an actuating electromagnet ( 9 ) for moving the axle ( 11 ) and membrane ( 3 ) to and fro to expand and contract the pump chamber ( 4 ), wherein the actuating electromagnet ( 9 ) is arranged to operate in two separate and distinct operating modes, in a first operating mode moving the membrane ( 3 ) in an inaudible frequency suitable for pumping a medium into and out of the pump chamber ( 4 ), and in a second operating mode moving the membrane ( 3 ) in a frequency in an audible frequency region for generating an audible alarm, and a control unit for increasing the frequency by activation and deactivation of the electromagnet ( 9 ) to increase vibration frequency of the membrane ( 3 ) to vibrate in the second operating mode where response time of the oscillating membrane ( 3 ) results in a smaller oscillation amplitude of the membrane ( 3 ) and the non-return valves ( 6 , 8 ) are unaffected by the membrane ( 3 ) oscillation and thus prevented from opening and closing.