STEPPED PUMP FOAM DISPENSER

摘要

A pump (10) for dispensing liquid from a reservoir (60) comprising: a piston-forming element (14) axially received in a piston chamber-forming member (12) and having a central axially extending hollow stem (38) with a central passageway (46) having an outlet (48) from which liquid is dispensed, at least one annular chamber (64,66) formed annularly about the stem (38) between the piston forming element (14) and the piston chamber-forming member (12) wherein said piston-forming element (14) has a bellows member (200) with a bellows chamber (186) open to the passageway (46), the bellows member (200) being collapsible to increase and decrease the volume of the bellows chamber (186) with reciprocal sliding of the piston-forming element (14) between a retracted position and an extended position to draw fluid through the outlet (48) and to expel fluid in the bellows chamber (186) out the outlet (48).