Rotational metering gasket pump

A rotational metering pump comprising:

• a sleeve comprising a side hole, the sleeve receiving a gasket having a first gasket opening arranged around the side hole, the sleeve and gasket adapted to rotate axially within a housing having an inlet port connected to a fluid reservoir and an outlet port connected to a delivery cannula;
• the sleeve further comprising a helical groove having a first end and a second end;
• a plunger received within the sleeve and adapted to rotate and translate axially within the sleeve, wherein axial translation of the plunger within the sleeve changes a pump volume, the pump volume being in fluid communication with the side hole of the sleeve, the plunger further comprising a coupling member adapted to move within the helical groove and between the first end and the second end of the helical groove to cause the plunger to translate axially within the sleeve as the plunger is rotated;
• a motor adapted to rotate the plunger in a first direction causing the pump volume to increase when the sleeve is in the first orientation, and to rotate the sleeve and plunger together when the coupling member reaches the first end of the helical groove, such that the sleeve moves into the second orientation;
• an output gear transmits movement of the motor to the plunger;
• wherein the gasket is cylindrical and assembled onto the sleeve such that the sleeve is received within the cylindrical gasket;
• wherein the gasket forms a seal between the sleeve and housing permitting fluid to pass through the first gasket opening between the pump volume and the inlet port or the outlet port.