Patent ID: 8512011

Claim:
A fluid pump for a fuel dispensing unit comprising: a pump housing with a first chamber having a first side and a second chamber having a second side; a first fluid inlet and a first fluid outlet coupled to the first chamber; a first outlet valve disposed on the first fluid outlet; a second fluid inlet and a second fluid outlet coupled to the second chamber; an inlet valve disposed on the second fluid inlet; the first chamber and the second chamber being separated by a movable piston having a cross sectional area and arranged to repeatedly decrease and increase a volume of the first chamber and a volume of the second chamber, the piston comprising a magnetic device, wherein an electromagnetic controller is configured to move the piston by altering a magnetic field, for repeatedly-decreasing and increasing the volume of the first chamber and the volume of the second chamber; a fluid flow passage directly connected to first chamber near the first side and to the second chamber near the second side, the fluid flow passage permitting fluid to flow from the first chamber to the second chamber without passing through any of the first fluid inlet, the first fluid outlet, the second fluid inlet and the second fluid outlet; and a control unit that controls how much fluid passes from the first chamber through the fluid flow passage to the second chamber.