Liquid hand cleaner foam dispensing as spray and liquid stream

A piston pump arrangement for dispensing a liquid from at least one discharge outlet comprising:

• the pump arrangement including a piston-forming element coaxially reciprocally slidable along an axis within a piston chamber-forming body between a retracted position and a withdrawn position in a cycle of operation in which movement from the retracted position to the withdrawn position is a withdrawal stroke and movement from the withdrawn position to the retracted position is a retraction stroke,
• the piston chamber-forming body including an inner chamber coaxial about the axis having a cylindrical chamber wall, an inner end and an open outer end, the inner end of the inner chamber in communication with a reservoir of the liquid to be dispensed via a first liquid inlet, a one-way inlet valve across the first liquid inlet permitting liquid flow from the reservoir to into the inner chamber but preventing liquid flow from the inner chamber to the reservoir,
• the piston chamber-forming body including a stepped outer chamber coaxial about the axis having a chamber wall, an open inner end and an open outer end,
• the open outer end of the inner chamber opening axially outwardly into the open inner end of the outer chamber,
• the chamber wall of the outer chamber having a cylindrical inner portion having a diameter and a cylindrical outer portion having a diameter which is less than the diameter of the cylindrical inner portion, the cylindrical inner portion opening axially outwardly into the cylindrical outer portion,
• the piston-forming element having an inner end and an outer end,
• the piston-forming element coaxially received within the piston chamber-forming body with the inner end of the piston-forming element within the inner chamber and the outer end of the end piston-forming element extending axially outwardly from the open outer end of the outer chamber,
• the piston-forming element having a central stem coaxially about the axis with at least one passageway within the stem extending axially outwardly from a closed inner end to an outer outlet end at the outer end of the end piston-forming element in communication with the at least one discharge outlet,
• a first inner disc extending radially outwardly from the stem into engagement with the chamber wall of the inner chamber to permit liquid flow axially outwardly therepast but prevent liquid flow axially inwardly therepast,
• a first outer disc extending radially outwardly from the stem into engagement with the chamber wall of the inner chamber to prevent liquid flow axially inwardly and outwardly therepast, the first outer disc located on the stem spaced axially outwardly from the first inner disc,
• a first port on the stem axially between the first inner disc and the first outer disc providing communication radially through the stem to the passageway,
• a sealing disc extending radially outwardly from the stem into engagement with the cylindrical inner portion of chamber wall of the outer chamber to prevent liquid flow axially inwardly and outwardly therepast,
• the sealing disc located on the stem spaced axially outwardly from the first outer disc,
• a second inner disc extending radially outwardly from the stem into engagement with the cylindrical outer portion of chamber wall of the outer chamber to permit liquid flow axially outwardly therepast but prevent liquid flow axially inwardly therepast, the second inner disc located on the stem spaced axially outwardly from the sealing disc,
• a second outer disc extending radially outwardly from the stem into engagement with the cylindrical outer portion of chamber wall of the outer chamber to prevent liquid flow axially inwardly and outwardly therepast, the second outer disc located on the stem spaced axially outwardly from the second inner disc,
• a second port on the stem axially between the first outer disc and the second outer disc providing communication radially through the stem to the passageway,
• a variable volume first liquid compartment defined in the inner chamber between the one-way inlet valve and the first outer disc, the first liquid compartment having a volume that increases in the withdrawal stroke drawing liquid from the reservoir through the first liquid inlet past the one-way inlet valve into the first liquid compartment, the volume of the first liquid compartment decreases in the retraction stroke forcing liquid axially outwardly past the first inner disc to between the first inner disc and the second inner disc to the first port, through the first port into the passageway and via the passageway to the at least one discharge outlet,
• a variable volume second liquid compartment defined in the outer chamber between the sealing disc and the second outer disc,
• the piston-forming element having a second liquid inlet placing the second liquid compartment in communication with the reservoir,
• the second liquid compartment having a volume that increases in the reaction stroke drawing liquid from the reservoir through the second liquid inlet past the sealing disc into the second liquid compartment, the volume of the second liquid compartment decreases in the withdrawal stroke forcing the liquid axially outwardly past the second inner disc to between the second inner disc and the second outer disc to the second port and through the second port into the passageway and via the passageway to the at least one discharge outlet.