US Patent 11596273 Sequentially activated multi-diaphragm foam pumps, refill units and dispenser systems

A foam dispenser includes a housing, a drive motor, and a foam pump. The foam pump includes a pump housing, and a molded multi-chamber diaphragm. The molded multi-chamber diaphragm includes a liquid pump diaphragm having a liquid pump stem and two or more air pump chambers each having an air pump stem. The length of the liquid pump stem is longer than the air pump stem. The foam pump further includes one or more outlet valves, a mixing chamber, an outlet for dispensing foam wherein the outlet is in fluid communication with the foam cartridge; and an actuator for sequentially actuating the liquid pump chamber and the two or more air pump chambers, wherein there is lost motion between the actuator and the liquid pump diaphragm.