Centrifugal pump

1. A centrifugal pump comprising:

one or more pumping stages;

a pressure controlled valve inside the centrifugal pump for supporting self-priming, the pressure controlled valve comprising a pretensioned leaf spring and a valve seat, the pretensioned leaf spring being configured to move from an opened position, in which the leaf spring is distanced from the valve seat to a closed position, in which the pretensioned leaf spring closes the valve seat, with a speed caused by fluid flow from said one or more pumping stages, the pretensioned leaf spring and the valve seat being arranged for dampening the speed of the pretensioned leaf spring caused by the fluid flow, wherein the pretensioned leaf spring has a preclosed position, in which the pressure controlled valve is partially closed;

a leaf spring support, wherein the valve seat is arranged eccentric with respect to a center of the leaf spring support.

2. The centrifugal pump according to claim 1 , wherein the pretensioned leaf spring has at least one inherent stable position, which is the opened position and is forced into the preclosed and the closed positions by fluid forces acting on the pretensioned leaf spring.

3. The centrifugal pump according to according claim 1 , wherein the pretensioned leaf spring has two inherent stable positions, the opened position and the closed position, wherein the pretensioned leaf spring is held in the closed position by fluid forces.

4. The centrifugal pump according to claim 1 , wherein the pretensioned leaf spring has a semi-stable position which is the preclosed position.

5. The centrifugal pump according to claim 1 , wherein the valve seat is distanced from the pretensioned leaf spring in the pre-closed position of the pretensioned leaf spring.

6. The centrifugal pump according to claim 1 , further comprising a bypass in parallel to the pressure controlled valve, wherein the bypass is closed by the pretensioned leaf spring in the preclosing position of the pretensioned leaf spring.

7. The centrifugal pump according to claim 1 , wherein the one or more pumping stages comprises a plurality of pumping stages to form a multistage centrifugal pump, wherein the pressure controlled valve is arranged between a suction side of the multistage centrifugal pump and a pressure side of the multistage centrifugal pump.

8. A domestic waterworks comprising a centrifugal pump, the centrifugal pump comprising:

one or more pumping stages; and

a pressure controlled valve inside the centrifugal pump for supporting self-priming, the pressure controlled valve comprising a pretensioned leaf spring and a valve seat, the pretensioned leaf spring being configured to move from an opened position, in which the pretensioned leaf spring is distanced from the valve seat to a closed position with a speed caused by fluid flow from said one or more pumping stages, in which the pretensioned leaf spring closes the valve seat, a center of the pretensioned leaf spring and a center of the valve seat being arranged offset relative to each other.

9. The domestic waterworks according to claim 8 , wherein the pretensioned leaf spring has a preclosed position, in which the pressure controlled valve is partially closed.

10. The domestic waterworks according to claim 9 , wherein the pretensioned leaf spring has at least one inherent stable position, which is the opened position and is forced into the preclosed and the closed positions by fluid forces acting on the pretensioned leaf spring.

11. The domestic waterworks according to claim 9 , wherein the pretensioned leaf spring has two inherent stable positions, the opened position and the closed position, wherein the pretensioned leaf spring is held in the closed position by fluid forces.

12. The domestic waterworks according to claim 9 , wherein the pretensioned leaf spring has a semi-stable position which is the preclosed position.

13. The domestic waterworks according to claim 8 , further comprising a leaf spring support, wherein the valve seat is arranged off-center with respect to the leaf spring support.

14. A centrifugal pump comprising:

a pumping stage;

a pressure controlled valve in flow communication with said pumping stage, said pressure controlled valve including a valve seat and a leaf spring movable between a closed position and an opened position, said closed position having said leaf spring arranged against said valve seat and blocking fluid flow through said valve seat, said opened position having said leaf spring spaced from said valve seat and allowing the fluid flow through said valve seat, said leaf spring being pretensioned into said opened position, said pressure control valve being configured to move said leaf spring from said open position to said closed position with a speed caused by a force of fluid from said pumping stage, said valve seat defining a bypass for the fluid flow;

dampening means for slowing said speed of said leaf spring as said leaf spring approaches said valve seat, said dampening means including a center of said bypass being offset from a center of said leaf spring.

15. The centrifugal pump in accordance with claim 14 , wherein:

said dampening means slows the speed of the leaf spring before the leaf spring closes the valve seat.