Rotating reciprocating piston pump with a barrel cam

A metering pump assembly comprising:

• a motor, wherein the motor comprises a motor shaft positioned along an axis aligned with the motor shaft, wherein the motor shaft moves in a rotational manner along an axis of the motor shaft when energized by the motor;
• a pump housing, wherein the pump housing comprises a trailing end and a closed leading end;
• a piston positioned within the pump housing, wherein the piston comprises a trailing end and a leading end, wherein the trailing end of the piston is connected to the motor shaft and the motor along the axis of the motor shaft, wherein a space is provided between the leading end of the piston and the closed leading end of the pump housing, wherein the space fluctuates in size depending on a position of the piston within the pump housing;
• an inlet port, wherein the inlet port extends through the pump housing;
• an outlet port, wherein the outlet port extends through the pump housing;
• a first barrel cam half, wherein the first barrel cam half comprises a first barrel cam half first angled cam edge, a first barrel cam half second angled cam edge on a side opposing the first barrel cam half first angled cam edge, wherein the first barrel cam half first angled cam edge and the first barrel cam half second angled cam edge converge to form a first barrel cam half first cam flat on a first barrel cam half trailing end and wherein the first barrel cam half first angled cam edge and the first barrel cam half second angled cam edge converge to form a first barrel cam half second cam flat on a first barrel cam half leading end, wherein the first barrel cam flat first cam flat and the first barrel cam flat second cam flat are positioned to face a first same direction;
• a second barrel cam half, wherein the second barrel cam half comprises a second barrel cam half first angled cam edge, a second barrel cam half second angled cam edge on a side opposing the second barrel cam half first angled cam edge, wherein the second barrel cam half first angled cam edge and the second barrel cam half second angled cam edge converge to form a second barrel cam half first cam flat on a second barrel cam half trailing end and wherein the second barrel cam half first angled cam edge and the second barrel cam half second angled cam edge converge to form a second barrel cam half second cam flat on a second barrel cam half leading end, wherein the second barrel cam flat first cam flat and the second barrel cam flat second cam flat are positioned to face a second same direction;
• a cam follower pin, wherein the cam follower pin is positioned within a peripheral slot between the first barrel cam half and the second barrel cam half,
• wherein the first barrel cam half and the second barrel cam half circumscribe the piston,
• wherein rotational movement of the motor shaft imparts rotational movement upon the piston and indirectly imparts reciprocal movement of the piston through movement of the cam follower pin within the peripheral slot between the first barrel cam half and the second barrel cam half, and
• wherein the piston remains aligned with the axis of the motor shaft during rotational and reciprocal movement of the piston without having to angle the piston with respect to the motor shaft to generate reciprocal movement of the piston within the pump housing.