Abstract: A fluid dispensing system includes a motor housing and a piston pump assembly connected to the motor housing. A motor is mounted within the motor housing. The piston pump assembly includes a pump housing, a cartridge having a first end that extends into a second end of the pump housing, a piston that extends into a first end of the pump housing and the first end of the cartridge, and a packing stack within the cartridge and adjacent an inner surface of the cartridge and through which the piston extends. The cartridge is configured to be removed from the pump housing, and removal of the cartridge removes the packing stack from within the pump housing while leaving the pump housing connected to the motor housing.

Abstract: A piston rod assembly includes a piston rod having a first end configured to contact fluid, a packing retainer through which the piston rod extends, and one or more packing rings. The packing retainer includes one or more leakage ports forming passageways between an inner surface and an outer surface of the packing retainer. The one or more packing rings surround the piston rod, are adjacent the inner surface of the packing retainer, and are positioned between the one or more leakage ports and a bottom end of the packing retainer. The one or more leakage ports are positioned so that fluid that leaks past the one or more packing rings will flow through the one or more leakage ports.

Abstract: A paint sprayer includes an end bell, a motor connected to the end bell, a pump drive connected to the end bell, a pair of protrusions attached to an extending from the end bell such that each protrusion is cantilevered from the end bell, and a pump assembly comprising a pair of mounting holes and containing a piston. The pair of mounting holes is adapted to receive and slide onto the pair of protrusions to mount the pump assembly on the end bell as well as slide off of the pair of protrusions to remove the pump assembly from the end bell. The pump drive is configured to covert rotational motion output by the motor to reciprocal motion. The pump assembly is configured to pump paint when reciprocated by the pump drive while mounted on the end bell.

Abstract: A piston rod for pumping paint includes an elongated cylindrical stem and a piston rod cap connected to the cylindrical stem. The cylindrical stem is formed from metal and has an outer diameter that is uniform along most or all of a length of the cylindrical stem. The piston rod cap is cylindrical and formed from metal. The piston rod cap includes an annular top portion that has an outer diameter that is larger than the outer diameter of the cylindrical stem, an annular bottom portion that has an outer diameter that is larger than the outer diameter of the cylindrical stem, and an exterior recess located between the annular top and bottom portions. The recess has an outer diameter that is smaller than the outer diameters of the annular top and bottom portions.