A pump engine, comprising: an accumulator, comprising: a first opening at one end of the accumulator; a second opening at an end opposite the first opening; a valve seat positioned on an interior of the accumulator between the first opening and the second opening; a product chamber between the valve seat and the second opening; a retaining ring circumscribing the second opening and projecting outward therefrom; a valve seated in the valve seat; a piston seal seated in the product chamber of the accumulator, the piston seal comprising: a central portion; a piston seal opening through the central portion; an output cylinder, comprising: a base wall; a cylindrical wall extending off of the base wall and defining a cavity; at least one output stop within the cavity; a plug seal wall extending off of the base wall in a direction opposite the cylindrical wall; a latch wall extending off of the base wall in the same direction as the plug seal wall; a piston stem, comprising: a fluid lock at one end of the piston stem; an output opening at an end opposite the fluid lock; at least one input opening adjacent the fluid lock; a piston stem flange extending outward from an exterior wall of the piston stem; wherein a portion of the piston stem and the piston stem flange are positioned within the cavity of the output cylinder, the output opening of the piston stem is outside of the output cylinder, a portion of the piston stem extends through the piston seal opening, the fluid lock is on a side of the piston seal opposite the output cylinder, and the accumulator retaining ring is seated between the plug seal wall and the latch wall of the output cylinder; wherein application of an actuation force on the piston stem moves the fluid lock into a volume in the product chamber and exposes the at least one input opening to product in the product chamber, allowing fluid to flow through the at least one input opening; and wherein release of the actuation force on the piston stem moves the fluid lock out of the volume in the product chamber, creating a vacuum, drawing product back into the product chamber through the at least one input opening. an accumulator, comprising: a first opening at one end of the accumulator; a second opening at an end opposite the first opening; a valve seat positioned on an interior of the accumulator between the first opening and the second opening; a product chamber between the valve seat and the second opening; a retaining ring circumscribing the second opening and projecting outward therefrom; a first opening at one end of the accumulator; a second opening at an end opposite the first opening; a valve seat positioned on an interior of the accumulator between the first opening and the second opening; a product chamber between the valve seat and the second opening; a retaining ring circumscribing the second opening and projecting outward therefrom; a valve seated in the valve seat; a piston seal seated in the product chamber of the accumulator, the piston seal comprising: a central portion; a piston seal opening through the central portion; a central portion; a piston seal opening through the central portion; an output cylinder, comprising: a base wall; a cylindrical wall extending off of the base wall and defining a cavity; at least one output stop within the cavity; a plug seal wall extending off of the base wall in a direction opposite the cylindrical wall; a latch wall extending off of the base wall in the same direction as the plug seal wall; a base wall; a cylindrical wall extending off of the base wall and defining a cavity; at least one output stop within the cavity; a plug seal wall extending off of the base wall in a direction opposite the cylindrical wall; a latch wall extending off of the base wall in the same direction as the plug seal wall; a piston stem, comprising: a fluid lock at one end of the piston stem; an output opening at an end opposite the fluid lock; at least one input opening adjacent the fluid lock; a piston stem flange extending outward from an exterior wall of the piston stem; a fluid lock at one end of the piston stem; an output opening at an end opposite the fluid lock; at least one input opening adjacent the fluid lock; a piston stem flange extending outward from an exterior wall of the piston stem; wherein a portion of the piston stem and the piston stem flange are positioned within the cavity of the output cylinder, the output opening of the piston stem is outside of the output cylinder, a portion of the piston stem extends through the piston seal opening, the fluid lock is on a side of the piston seal opposite the output cylinder, and the accumulator retaining ring is seated between the plug seal wall and the latch wall of the output cylinder; wherein application of an actuation force on the piston stem moves the fluid lock into a volume in the product chamber and exposes the at least one input opening to product in the product chamber, allowing fluid to flow through the at least one input opening; and wherein release of the actuation force on the piston stem moves the fluid lock out of the volume in the product chamber, creating a vacuum, drawing product back into the product chamber through the at least one input opening.