Multi-chamber impeller pump

A pump comprising:

• an impeller including a hub and a plurality of blades extending radially from the hub, each blade having an end;
• a plurality of circumferentially spaced cams defining an impeller chamber within which the impeller is rotatably mounted;
• wherein each cam includes an engagement edge, an arcuate cam surface sloping radially inward from the engagement edge, and a lobe that extends radially inward from the arcuate cam surface;
• and
• a plurality of circumferentially spaced evacuation ports, each evacuation port being proximal to the intersection of the arcuate cam surface and the lobe of a respective cam;
• wherein, as the impeller rotates, a corresponding end of a leading blade of the plurality of blades contacts a respective engagement edge and then a corresponding end of a trailing blade of the plurality of blades subsequently contacts the respective engagement edge thereby forming a unit chamber between:
• the leading and trailing blades;
• the impeller hub;
• and the respective cam of the plurality of circumferentially spaced cams;
• and
• wherein, as the impeller continues to rotate, the end of the leading blade contacts a respective lobe and displaces the leading blade to decrease the volume of the unit chamber and expel fluid from the unit chamber through a respective evacuation port.