Foam pump with improved piston structure

摘要

A foam pump includes a piston housing and a piston assembly received in the piston housing thereby defining a collapsible liquid chamber and a collapsible air chamber. The piston assembly includes a premix chamber separated from both the collapsible liquid chamber and the collapsible air chamber by a premix chamber wall and fluidly communicating with both the collapsible liquid chamber and the collapsible air chamber through a mix aperture in the premix chamber wall. A biasing member urges the piston assembly to a non-actuated position. The foam pump is actuated by urging the piston assembly against the biasing member to an actuated position in which the collapsible air chamber and the collapsible liquid chamber are reduced in volume such that air and foamable liquid are expelled from their respective collapsible air chamber and collapsible liquid chamber through the mix aperture. The simultaneous movement of the air and foamable liquid through the mix aperture causes a turbulent mixing thereof.